2 # (C) Copyright 2000 - 2013
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # SPDX-License-Identifier: GPL-2.0+
11 This directory contains the source code for U-Boot, a boot loader for
12 Embedded boards based on PowerPC, ARM, MIPS and several other
13 processors, which can be installed in a boot ROM and used to
14 initialize and test the hardware or to download and run application
17 The development of U-Boot is closely related to Linux: some parts of
18 the source code originate in the Linux source tree, we have some
19 header files in common, and special provision has been made to
20 support booting of Linux images.
22 Some attention has been paid to make this software easily
23 configurable and extendable. For instance, all monitor commands are
24 implemented with the same call interface, so that it's very easy to
25 add new commands. Also, instead of permanently adding rarely used
26 code (for instance hardware test utilities) to the monitor, you can
27 load and run it dynamically.
33 In general, all boards for which a configuration option exists in the
34 Makefile have been tested to some extent and can be considered
35 "working". In fact, many of them are used in production systems.
37 In case of problems see the CHANGELOG and CREDITS files to find out
38 who contributed the specific port. The boards.cfg file lists board
41 Note: There is no CHANGELOG file in the actual U-Boot source tree;
42 it can be created dynamically from the Git log using:
50 In case you have questions about, problems with or contributions for
51 U-Boot you should send a message to the U-Boot mailing list at
52 <u-boot@lists.denx.de>. There is also an archive of previous traffic
53 on the mailing list - please search the archive before asking FAQ's.
54 Please see http://lists.denx.de/pipermail/u-boot and
55 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
58 Where to get source code:
59 =========================
61 The U-Boot source code is maintained in the git repository at
62 git://www.denx.de/git/u-boot.git ; you can browse it online at
63 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
65 The "snapshot" links on this page allow you to download tarballs of
66 any version you might be interested in. Official releases are also
67 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
70 Pre-built (and tested) images are available from
71 ftp://ftp.denx.de/pub/u-boot/images/
77 - start from 8xxrom sources
78 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
80 - make it easier to add custom boards
81 - make it possible to add other [PowerPC] CPUs
82 - extend functions, especially:
83 * Provide extended interface to Linux boot loader
86 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
87 - create ARMBoot project (http://sourceforge.net/projects/armboot)
88 - add other CPU families (starting with ARM)
89 - create U-Boot project (http://sourceforge.net/projects/u-boot)
90 - current project page: see http://www.denx.de/wiki/U-Boot
96 The "official" name of this project is "Das U-Boot". The spelling
97 "U-Boot" shall be used in all written text (documentation, comments
98 in source files etc.). Example:
100 This is the README file for the U-Boot project.
102 File names etc. shall be based on the string "u-boot". Examples:
104 include/asm-ppc/u-boot.h
106 #include <asm/u-boot.h>
108 Variable names, preprocessor constants etc. shall be either based on
109 the string "u_boot" or on "U_BOOT". Example:
111 U_BOOT_VERSION u_boot_logo
112 IH_OS_U_BOOT u_boot_hush_start
118 Starting with the release in October 2008, the names of the releases
119 were changed from numerical release numbers without deeper meaning
120 into a time stamp based numbering. Regular releases are identified by
121 names consisting of the calendar year and month of the release date.
122 Additional fields (if present) indicate release candidates or bug fix
123 releases in "stable" maintenance trees.
126 U-Boot v2009.11 - Release November 2009
127 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
128 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
134 /arch Architecture specific files
135 /arc Files generic to ARC architecture
136 /cpu CPU specific files
137 /arc700 Files specific to ARC 700 CPUs
138 /lib Architecture specific library files
139 /arm Files generic to ARM architecture
140 /cpu CPU specific files
141 /arm720t Files specific to ARM 720 CPUs
142 /arm920t Files specific to ARM 920 CPUs
143 /at91 Files specific to Atmel AT91RM9200 CPU
144 /imx Files specific to Freescale MC9328 i.MX CPUs
145 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
146 /arm926ejs Files specific to ARM 926 CPUs
147 /arm1136 Files specific to ARM 1136 CPUs
148 /pxa Files specific to Intel XScale PXA CPUs
149 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
150 /lib Architecture specific library files
151 /avr32 Files generic to AVR32 architecture
152 /cpu CPU specific files
153 /lib Architecture specific library files
154 /blackfin Files generic to Analog Devices Blackfin architecture
155 /cpu CPU specific files
156 /lib Architecture specific library files
157 /m68k Files generic to m68k architecture
158 /cpu CPU specific files
159 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
160 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
161 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
162 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
163 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
164 /lib Architecture specific library files
165 /microblaze Files generic to microblaze architecture
166 /cpu CPU specific files
167 /lib Architecture specific library files
168 /mips Files generic to MIPS architecture
169 /cpu CPU specific files
170 /mips32 Files specific to MIPS32 CPUs
171 /mips64 Files specific to MIPS64 CPUs
172 /lib Architecture specific library files
173 /nds32 Files generic to NDS32 architecture
174 /cpu CPU specific files
175 /n1213 Files specific to Andes Technology N1213 CPUs
176 /lib Architecture specific library files
177 /nios2 Files generic to Altera NIOS2 architecture
178 /cpu CPU specific files
179 /lib Architecture specific library files
180 /openrisc Files generic to OpenRISC architecture
181 /cpu CPU specific files
182 /lib Architecture specific library files
183 /powerpc Files generic to PowerPC architecture
184 /cpu CPU specific files
185 /mpc5xx Files specific to Freescale MPC5xx CPUs
186 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
187 /mpc8xx Files specific to Freescale MPC8xx CPUs
188 /mpc8260 Files specific to Freescale MPC8260 CPUs
189 /mpc85xx Files specific to Freescale MPC85xx CPUs
190 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
191 /lib Architecture specific library files
192 /sh Files generic to SH architecture
193 /cpu CPU specific files
194 /sh2 Files specific to sh2 CPUs
195 /sh3 Files specific to sh3 CPUs
196 /sh4 Files specific to sh4 CPUs
197 /lib Architecture specific library files
198 /sparc Files generic to SPARC architecture
199 /cpu CPU specific files
200 /leon2 Files specific to Gaisler LEON2 SPARC CPU
201 /leon3 Files specific to Gaisler LEON3 SPARC CPU
202 /lib Architecture specific library files
203 /x86 Files generic to x86 architecture
204 /cpu CPU specific files
205 /lib Architecture specific library files
206 /api Machine/arch independent API for external apps
207 /board Board dependent files
208 /common Misc architecture independent functions
209 /disk Code for disk drive partition handling
210 /doc Documentation (don't expect too much)
211 /drivers Commonly used device drivers
212 /dts Contains Makefile for building internal U-Boot fdt.
213 /examples Example code for standalone applications, etc.
214 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
215 /include Header Files
216 /lib Files generic to all architectures
217 /libfdt Library files to support flattened device trees
218 /lzma Library files to support LZMA decompression
219 /lzo Library files to support LZO decompression
221 /post Power On Self Test
222 /spl Secondary Program Loader framework
223 /tools Tools to build S-Record or U-Boot images, etc.
225 Software Configuration:
226 =======================
228 Configuration is usually done using C preprocessor defines; the
229 rationale behind that is to avoid dead code whenever possible.
231 There are two classes of configuration variables:
233 * Configuration _OPTIONS_:
234 These are selectable by the user and have names beginning with
237 * Configuration _SETTINGS_:
238 These depend on the hardware etc. and should not be meddled with if
239 you don't know what you're doing; they have names beginning with
242 Later we will add a configuration tool - probably similar to or even
243 identical to what's used for the Linux kernel. Right now, we have to
244 do the configuration by hand, which means creating some symbolic
245 links and editing some configuration files. We use the TQM8xxL boards
249 Selection of Processor Architecture and Board Type:
250 ---------------------------------------------------
252 For all supported boards there are ready-to-use default
253 configurations available; just type "make <board_name>_defconfig".
255 Example: For a TQM823L module type:
258 make TQM823L_defconfig
260 For the Cogent platform, you need to specify the CPU type as well;
261 e.g. "make cogent_mpc8xx_defconfig". And also configure the cogent
262 directory according to the instructions in cogent/README.
268 U-Boot can be built natively to run on a Linux host using the 'sandbox'
269 board. This allows feature development which is not board- or architecture-
270 specific to be undertaken on a native platform. The sandbox is also used to
271 run some of U-Boot's tests.
273 See board/sandbox/README.sandbox for more details.
276 Board Initialisation Flow:
277 --------------------------
279 This is the intended start-up flow for boards. This should apply for both
280 SPL and U-Boot proper (i.e. they both follow the same rules). At present SPL
281 mostly uses a separate code path, but the funtion names and roles of each
282 function are the same. Some boards or architectures may not conform to this.
283 At least most ARM boards which use CONFIG_SPL_FRAMEWORK conform to this.
285 Execution starts with start.S with three functions called during init after
286 that. The purpose and limitations of each is described below.
289 - purpose: essential init to permit execution to reach board_init_f()
290 - no global_data or BSS
291 - there is no stack (ARMv7 may have one but it will soon be removed)
292 - must not set up SDRAM or use console
293 - must only do the bare minimum to allow execution to continue to
295 - this is almost never needed
296 - return normally from this function
299 - purpose: set up the machine ready for running board_init_r():
300 i.e. SDRAM and serial UART
301 - global_data is available
303 - BSS is not available, so you cannot use global/static variables,
304 only stack variables and global_data
306 Non-SPL-specific notes:
307 - dram_init() is called to set up DRAM. If already done in SPL this
311 - you can override the entire board_init_f() function with your own
313 - preloader_console_init() can be called here in extremis
314 - should set up SDRAM, and anything needed to make the UART work
315 - these is no need to clear BSS, it will be done by crt0.S
316 - must return normally from this function (don't call board_init_r()
319 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
320 this point the stack and global_data are relocated to below
321 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
325 - purpose: main execution, common code
326 - global_data is available
328 - BSS is available, all static/global variables can be used
329 - execution eventually continues to main_loop()
331 Non-SPL-specific notes:
332 - U-Boot is relocated to the top of memory and is now running from
336 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
337 CONFIG_SPL_STACK_R_ADDR points into SDRAM
338 - preloader_console_init() can be called here - typically this is
339 done by defining CONFIG_SPL_BOARD_INIT and then supplying a
340 spl_board_init() function containing this call
341 - loads U-Boot or (in falcon mode) Linux
345 Configuration Options:
346 ----------------------
348 Configuration depends on the combination of board and CPU type; all
349 such information is kept in a configuration file
350 "include/configs/<board_name>.h".
352 Example: For a TQM823L module, all configuration settings are in
353 "include/configs/TQM823L.h".
356 Many of the options are named exactly as the corresponding Linux
357 kernel configuration options. The intention is to make it easier to
358 build a config tool - later.
361 The following options need to be configured:
363 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
365 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
367 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
368 Define exactly one, e.g. CONFIG_ATSTK1002
370 - CPU Module Type: (if CONFIG_COGENT is defined)
371 Define exactly one of
373 --- FIXME --- not tested yet:
374 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
375 CONFIG_CMA287_23, CONFIG_CMA287_50
377 - Motherboard Type: (if CONFIG_COGENT is defined)
378 Define exactly one of
379 CONFIG_CMA101, CONFIG_CMA102
381 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
382 Define one or more of
385 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
386 Define one or more of
387 CONFIG_LCD_HEARTBEAT - update a character position on
388 the LCD display every second with
391 - Marvell Family Member
392 CONFIG_SYS_MVFS - define it if you want to enable
393 multiple fs option at one time
394 for marvell soc family
396 - 8xx CPU Options: (if using an MPC8xx CPU)
397 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
398 get_gclk_freq() cannot work
399 e.g. if there is no 32KHz
400 reference PIT/RTC clock
401 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
404 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
405 CONFIG_SYS_8xx_CPUCLK_MIN
406 CONFIG_SYS_8xx_CPUCLK_MAX
407 CONFIG_8xx_CPUCLK_DEFAULT
408 See doc/README.MPC866
410 CONFIG_SYS_MEASURE_CPUCLK
412 Define this to measure the actual CPU clock instead
413 of relying on the correctness of the configured
414 values. Mostly useful for board bringup to make sure
415 the PLL is locked at the intended frequency. Note
416 that this requires a (stable) reference clock (32 kHz
417 RTC clock or CONFIG_SYS_8XX_XIN)
419 CONFIG_SYS_DELAYED_ICACHE
421 Define this option if you want to enable the
422 ICache only when Code runs from RAM.
427 Specifies that the core is a 64-bit PowerPC implementation (implements
428 the "64" category of the Power ISA). This is necessary for ePAPR
429 compliance, among other possible reasons.
431 CONFIG_SYS_FSL_TBCLK_DIV
433 Defines the core time base clock divider ratio compared to the
434 system clock. On most PQ3 devices this is 8, on newer QorIQ
435 devices it can be 16 or 32. The ratio varies from SoC to Soc.
437 CONFIG_SYS_FSL_PCIE_COMPAT
439 Defines the string to utilize when trying to match PCIe device
440 tree nodes for the given platform.
442 CONFIG_SYS_PPC_E500_DEBUG_TLB
444 Enables a temporary TLB entry to be used during boot to work
445 around limitations in e500v1 and e500v2 external debugger
446 support. This reduces the portions of the boot code where
447 breakpoints and single stepping do not work. The value of this
448 symbol should be set to the TLB1 entry to be used for this
451 CONFIG_SYS_FSL_ERRATUM_A004510
453 Enables a workaround for erratum A004510. If set,
454 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
455 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
457 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
458 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
460 Defines one or two SoC revisions (low 8 bits of SVR)
461 for which the A004510 workaround should be applied.
463 The rest of SVR is either not relevant to the decision
464 of whether the erratum is present (e.g. p2040 versus
465 p2041) or is implied by the build target, which controls
466 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
468 See Freescale App Note 4493 for more information about
471 CONFIG_A003399_NOR_WORKAROUND
472 Enables a workaround for IFC erratum A003399. It is only
473 required during NOR boot.
475 CONFIG_A008044_WORKAROUND
476 Enables a workaround for T1040/T1042 erratum A008044. It is only
477 required during NAND boot and valid for Rev 1.0 SoC revision
479 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
481 This is the value to write into CCSR offset 0x18600
482 according to the A004510 workaround.
484 CONFIG_SYS_FSL_DSP_DDR_ADDR
485 This value denotes start offset of DDR memory which is
486 connected exclusively to the DSP cores.
488 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
489 This value denotes start offset of M2 memory
490 which is directly connected to the DSP core.
492 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
493 This value denotes start offset of M3 memory which is directly
494 connected to the DSP core.
496 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
497 This value denotes start offset of DSP CCSR space.
499 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
500 Single Source Clock is clocking mode present in some of FSL SoC's.
501 In this mode, a single differential clock is used to supply
502 clocks to the sysclock, ddrclock and usbclock.
504 CONFIG_SYS_CPC_REINIT_F
505 This CONFIG is defined when the CPC is configured as SRAM at the
506 time of U-boot entry and is required to be re-initialized.
509 Indicates this SoC supports deep sleep feature. If deep sleep is
510 supported, core will start to execute uboot when wakes up.
512 - Generic CPU options:
513 CONFIG_SYS_GENERIC_GLOBAL_DATA
514 Defines global data is initialized in generic board board_init_f().
515 If this macro is defined, global data is created and cleared in
516 generic board board_init_f(). Without this macro, architecture/board
517 should initialize global data before calling board_init_f().
519 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
521 Defines the endianess of the CPU. Implementation of those
522 values is arch specific.
525 Freescale DDR driver in use. This type of DDR controller is
526 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
529 CONFIG_SYS_FSL_DDR_ADDR
530 Freescale DDR memory-mapped register base.
532 CONFIG_SYS_FSL_DDR_EMU
533 Specify emulator support for DDR. Some DDR features such as
534 deskew training are not available.
536 CONFIG_SYS_FSL_DDRC_GEN1
537 Freescale DDR1 controller.
539 CONFIG_SYS_FSL_DDRC_GEN2
540 Freescale DDR2 controller.
542 CONFIG_SYS_FSL_DDRC_GEN3
543 Freescale DDR3 controller.
545 CONFIG_SYS_FSL_DDRC_GEN4
546 Freescale DDR4 controller.
548 CONFIG_SYS_FSL_DDRC_ARM_GEN3
549 Freescale DDR3 controller for ARM-based SoCs.
552 Board config to use DDR1. It can be enabled for SoCs with
553 Freescale DDR1 or DDR2 controllers, depending on the board
557 Board config to use DDR2. It can be eanbeld for SoCs with
558 Freescale DDR2 or DDR3 controllers, depending on the board
562 Board config to use DDR3. It can be enabled for SoCs with
563 Freescale DDR3 or DDR3L controllers.
566 Board config to use DDR3L. It can be enabled for SoCs with
570 Board config to use DDR4. It can be enabled for SoCs with
573 CONFIG_SYS_FSL_IFC_BE
574 Defines the IFC controller register space as Big Endian
576 CONFIG_SYS_FSL_IFC_LE
577 Defines the IFC controller register space as Little Endian
579 CONFIG_SYS_FSL_PBL_PBI
580 It enables addition of RCW (Power on reset configuration) in built image.
581 Please refer doc/README.pblimage for more details
583 CONFIG_SYS_FSL_PBL_RCW
584 It adds PBI(pre-boot instructions) commands in u-boot build image.
585 PBI commands can be used to configure SoC before it starts the execution.
586 Please refer doc/README.pblimage for more details
589 It adds a target to create boot binary having SPL binary in PBI format
590 concatenated with u-boot binary.
592 CONFIG_SYS_FSL_DDR_BE
593 Defines the DDR controller register space as Big Endian
595 CONFIG_SYS_FSL_DDR_LE
596 Defines the DDR controller register space as Little Endian
598 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
599 Physical address from the view of DDR controllers. It is the
600 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
601 it could be different for ARM SoCs.
603 CONFIG_SYS_FSL_DDR_INTLV_256B
604 DDR controller interleaving on 256-byte. This is a special
605 interleaving mode, handled by Dickens for Freescale layerscape
608 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
609 Number of controllers used as main memory.
611 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
612 Number of controllers used for other than main memory.
614 CONFIG_SYS_FSL_SEC_BE
615 Defines the SEC controller register space as Big Endian
617 CONFIG_SYS_FSL_SEC_LE
618 Defines the SEC controller register space as Little Endian
620 - Intel Monahans options:
621 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
623 Defines the Monahans run mode to oscillator
624 ratio. Valid values are 8, 16, 24, 31. The core
625 frequency is this value multiplied by 13 MHz.
627 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
629 Defines the Monahans turbo mode to oscillator
630 ratio. Valid values are 1 (default if undefined) and
631 2. The core frequency as calculated above is multiplied
635 CONFIG_SYS_INIT_SP_OFFSET
637 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
638 pointer. This is needed for the temporary stack before
641 CONFIG_SYS_MIPS_CACHE_MODE
643 Cache operation mode for the MIPS CPU.
644 See also arch/mips/include/asm/mipsregs.h.
646 CONF_CM_CACHABLE_NO_WA
649 CONF_CM_CACHABLE_NONCOHERENT
653 CONF_CM_CACHABLE_ACCELERATED
655 CONFIG_SYS_XWAY_EBU_BOOTCFG
657 Special option for Lantiq XWAY SoCs for booting from NOR flash.
658 See also arch/mips/cpu/mips32/start.S.
660 CONFIG_XWAY_SWAP_BYTES
662 Enable compilation of tools/xway-swap-bytes needed for Lantiq
663 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
664 be swapped if a flash programmer is used.
667 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
669 Select high exception vectors of the ARM core, e.g., do not
670 clear the V bit of the c1 register of CP15.
672 CONFIG_SYS_THUMB_BUILD
674 Use this flag to build U-Boot using the Thumb instruction
675 set for ARM architectures. Thumb instruction set provides
676 better code density. For ARM architectures that support
677 Thumb2 this flag will result in Thumb2 code generated by
680 CONFIG_ARM_ERRATA_716044
681 CONFIG_ARM_ERRATA_742230
682 CONFIG_ARM_ERRATA_743622
683 CONFIG_ARM_ERRATA_751472
684 CONFIG_ARM_ERRATA_794072
685 CONFIG_ARM_ERRATA_761320
687 If set, the workarounds for these ARM errata are applied early
688 during U-Boot startup. Note that these options force the
689 workarounds to be applied; no CPU-type/version detection
690 exists, unlike the similar options in the Linux kernel. Do not
691 set these options unless they apply!
694 CONFIG_TEGRA_SUPPORT_NON_SECURE
696 Support executing U-Boot in non-secure (NS) mode. Certain
697 impossible actions will be skipped if the CPU is in NS mode,
698 such as ARM architectural timer initialization.
701 Driver model is a new framework for devices in U-Boot
702 introduced in early 2014. U-Boot is being progressively
703 moved over to this. It offers a consistent device structure,
704 supports grouping devices into classes and has built-in
705 handling of platform data and device tree.
707 To enable transition to driver model in a relatively
708 painful fashion, each subsystem can be independently
709 switched between the legacy/ad-hoc approach and the new
710 driver model using the options below. Also, many uclass
711 interfaces include compatibility features which may be
712 removed once the conversion of that subsystem is complete.
713 As a result, the API provided by the subsystem may in fact
714 not change with driver model.
716 See doc/driver-model/README.txt for more information.
720 Enable driver model. This brings in the core support,
721 including scanning of platform data on start-up. If
722 CONFIG_OF_CONTROL is enabled, the device tree will be
723 scanned also when available.
727 Enable driver model test commands. These allow you to print
728 out the driver model tree and the uclasses.
732 Enable some demo devices and the 'demo' command. These are
733 really only useful for playing around while trying to
734 understand driver model in sandbox.
738 Enable driver model in SPL. You will need to provide a
739 suitable malloc() implementation. If you are not using the
740 full malloc() enabled by CONFIG_SYS_SPL_MALLOC_START,
741 consider using CONFIG_SYS_MALLOC_SIMPLE. In that case you
742 must provide CONFIG_SYS_MALLOC_F_LEN to set the size.
743 In most cases driver model will only allocate a few uclasses
744 and devices in SPL, so 1KB should be enable. See
745 CONFIG_SYS_MALLOC_F_LEN for more details on how to enable
750 Enable driver model for serial. This replaces
751 drivers/serial/serial.c with the serial uclass, which
752 implements serial_putc() etc. The uclass interface is
753 defined in include/serial.h.
757 Enable driver model for GPIO access. The standard GPIO
758 interface (gpio_get_value(), etc.) is then implemented by
759 the GPIO uclass. Drivers provide methods to query the
760 particular GPIOs that they provide. The uclass interface
761 is defined in include/asm-generic/gpio.h.
765 Enable driver model for SPI. The SPI slave interface
766 (spi_setup_slave(), spi_xfer(), etc.) is then implemented by
767 the SPI uclass. Drivers provide methods to access the SPI
768 buses that they control. The uclass interface is defined in
769 include/spi.h. The existing spi_slave structure is attached
770 as 'parent data' to every slave on each bus. Slaves
771 typically use driver-private data instead of extending the
776 Enable driver model for SPI flash. This SPI flash interface
777 (spi_flash_probe(), spi_flash_write(), etc.) is then
778 implemented by the SPI flash uclass. There is one standard
779 SPI flash driver which knows how to probe most chips
780 supported by U-Boot. The uclass interface is defined in
781 include/spi_flash.h, but is currently fully compatible
782 with the old interface to avoid confusion and duplication
783 during the transition parent. SPI and SPI flash must be
784 enabled together (it is not possible to use driver model
785 for one and not the other).
789 Enable driver model for the Chrome OS EC interface. This
790 allows the cros_ec SPI driver to operate with CONFIG_DM_SPI
791 but otherwise makes few changes. Since cros_ec also supports
792 I2C and LPC (which don't support driver model yet), a full
793 conversion is not yet possible.
796 ** Code size options: The following options are enabled by
797 default except in SPL. Enable them explicitly to get these
802 Enable the dm_warn() function. This can use up quite a bit
803 of space for its strings.
807 Enable registering a serial device with the stdio library.
809 CONFIG_DM_DEVICE_REMOVE
811 Enable removing of devices.
813 - Linux Kernel Interface:
816 U-Boot stores all clock information in Hz
817 internally. For binary compatibility with older Linux
818 kernels (which expect the clocks passed in the
819 bd_info data to be in MHz) the environment variable
820 "clocks_in_mhz" can be defined so that U-Boot
821 converts clock data to MHZ before passing it to the
823 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
824 "clocks_in_mhz=1" is automatically included in the
827 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
829 When transferring memsize parameter to Linux, some versions
830 expect it to be in bytes, others in MB.
831 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
835 New kernel versions are expecting firmware settings to be
836 passed using flattened device trees (based on open firmware
840 * New libfdt-based support
841 * Adds the "fdt" command
842 * The bootm command automatically updates the fdt
844 OF_CPU - The proper name of the cpus node (only required for
845 MPC512X and MPC5xxx based boards).
846 OF_SOC - The proper name of the soc node (only required for
847 MPC512X and MPC5xxx based boards).
848 OF_TBCLK - The timebase frequency.
849 OF_STDOUT_PATH - The path to the console device
851 boards with QUICC Engines require OF_QE to set UCC MAC
854 CONFIG_OF_BOARD_SETUP
856 Board code has addition modification that it wants to make
857 to the flat device tree before handing it off to the kernel
859 CONFIG_OF_SYSTEM_SETUP
861 Other code has addition modification that it wants to make
862 to the flat device tree before handing it off to the kernel.
863 This causes ft_system_setup() to be called before booting
868 This define fills in the correct boot CPU in the boot
869 param header, the default value is zero if undefined.
873 U-Boot can detect if an IDE device is present or not.
874 If not, and this new config option is activated, U-Boot
875 removes the ATA node from the DTS before booting Linux,
876 so the Linux IDE driver does not probe the device and
877 crash. This is needed for buggy hardware (uc101) where
878 no pull down resistor is connected to the signal IDE5V_DD7.
880 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
882 This setting is mandatory for all boards that have only one
883 machine type and must be used to specify the machine type
884 number as it appears in the ARM machine registry
885 (see http://www.arm.linux.org.uk/developer/machines/).
886 Only boards that have multiple machine types supported
887 in a single configuration file and the machine type is
888 runtime discoverable, do not have to use this setting.
890 - vxWorks boot parameters:
892 bootvx constructs a valid bootline using the following
893 environments variables: bootfile, ipaddr, serverip, hostname.
894 It loads the vxWorks image pointed bootfile.
896 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
897 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
898 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
899 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
901 CONFIG_SYS_VXWORKS_ADD_PARAMS
903 Add it at the end of the bootline. E.g "u=username pw=secret"
905 Note: If a "bootargs" environment is defined, it will overwride
906 the defaults discussed just above.
908 - Cache Configuration:
909 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
910 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
911 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
913 - Cache Configuration for ARM:
914 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
916 CONFIG_SYS_PL310_BASE - Physical base address of PL310
917 controller register space
922 Define this if you want support for Amba PrimeCell PL010 UARTs.
926 Define this if you want support for Amba PrimeCell PL011 UARTs.
930 If you have Amba PrimeCell PL011 UARTs, set this variable to
931 the clock speed of the UARTs.
935 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
936 define this to a list of base addresses for each (supported)
937 port. See e.g. include/configs/versatile.h
939 CONFIG_PL011_SERIAL_RLCR
941 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
942 have separate receive and transmit line control registers. Set
943 this variable to initialize the extra register.
945 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
947 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
948 boot loader that has already initialized the UART. Define this
949 variable to flush the UART at init time.
951 CONFIG_SERIAL_HW_FLOW_CONTROL
953 Define this variable to enable hw flow control in serial driver.
954 Current user of this option is drivers/serial/nsl16550.c driver
957 Depending on board, define exactly one serial port
958 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
959 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
960 console by defining CONFIG_8xx_CONS_NONE
962 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
963 port routines must be defined elsewhere
964 (i.e. serial_init(), serial_getc(), ...)
967 Enables console device for a color framebuffer. Needs following
968 defines (cf. smiLynxEM, i8042)
969 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
971 VIDEO_HW_RECTFILL graphic chip supports
974 VIDEO_HW_BITBLT graphic chip supports
975 bit-blit (cf. smiLynxEM)
976 VIDEO_VISIBLE_COLS visible pixel columns
978 VIDEO_VISIBLE_ROWS visible pixel rows
979 VIDEO_PIXEL_SIZE bytes per pixel
980 VIDEO_DATA_FORMAT graphic data format
981 (0-5, cf. cfb_console.c)
982 VIDEO_FB_ADRS framebuffer address
983 VIDEO_KBD_INIT_FCT keyboard int fct
984 (i.e. i8042_kbd_init())
985 VIDEO_TSTC_FCT test char fct
987 VIDEO_GETC_FCT get char fct
989 CONFIG_CONSOLE_CURSOR cursor drawing on/off
990 (requires blink timer
992 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
993 CONFIG_CONSOLE_TIME display time/date info in
995 (requires CONFIG_CMD_DATE)
996 CONFIG_VIDEO_LOGO display Linux logo in
998 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
999 linux_logo.h for logo.
1000 Requires CONFIG_VIDEO_LOGO
1001 CONFIG_CONSOLE_EXTRA_INFO
1002 additional board info beside
1005 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
1006 a limited number of ANSI escape sequences (cursor control,
1007 erase functions and limited graphics rendition control).
1009 When CONFIG_CFB_CONSOLE is defined, video console is
1010 default i/o. Serial console can be forced with
1011 environment 'console=serial'.
1013 When CONFIG_SILENT_CONSOLE is defined, all console
1014 messages (by U-Boot and Linux!) can be silenced with
1015 the "silent" environment variable. See
1016 doc/README.silent for more information.
1018 CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
1020 CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
1024 CONFIG_BAUDRATE - in bps
1025 Select one of the baudrates listed in
1026 CONFIG_SYS_BAUDRATE_TABLE, see below.
1027 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
1029 - Console Rx buffer length
1030 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
1031 the maximum receive buffer length for the SMC.
1032 This option is actual only for 82xx and 8xx possible.
1033 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
1034 must be defined, to setup the maximum idle timeout for
1037 - Pre-Console Buffer:
1038 Prior to the console being initialised (i.e. serial UART
1039 initialised etc) all console output is silently discarded.
1040 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
1041 buffer any console messages prior to the console being
1042 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
1043 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
1044 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
1045 bytes are output before the console is initialised, the
1046 earlier bytes are discarded.
1048 'Sane' compilers will generate smaller code if
1049 CONFIG_PRE_CON_BUF_SZ is a power of 2
1051 - Safe printf() functions
1052 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
1053 the printf() functions. These are defined in
1054 include/vsprintf.h and include snprintf(), vsnprintf() and
1055 so on. Code size increase is approximately 300-500 bytes.
1056 If this option is not given then these functions will
1057 silently discard their buffer size argument - this means
1058 you are not getting any overflow checking in this case.
1060 - Boot Delay: CONFIG_BOOTDELAY - in seconds
1061 Delay before automatically booting the default image;
1062 set to -1 to disable autoboot.
1063 set to -2 to autoboot with no delay and not check for abort
1064 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
1066 See doc/README.autoboot for these options that
1067 work with CONFIG_BOOTDELAY. None are required.
1068 CONFIG_BOOT_RETRY_TIME
1069 CONFIG_BOOT_RETRY_MIN
1070 CONFIG_AUTOBOOT_KEYED
1071 CONFIG_AUTOBOOT_PROMPT
1072 CONFIG_AUTOBOOT_DELAY_STR
1073 CONFIG_AUTOBOOT_STOP_STR
1074 CONFIG_AUTOBOOT_DELAY_STR2
1075 CONFIG_AUTOBOOT_STOP_STR2
1076 CONFIG_ZERO_BOOTDELAY_CHECK
1077 CONFIG_RESET_TO_RETRY
1081 Only needed when CONFIG_BOOTDELAY is enabled;
1082 define a command string that is automatically executed
1083 when no character is read on the console interface
1084 within "Boot Delay" after reset.
1087 This can be used to pass arguments to the bootm
1088 command. The value of CONFIG_BOOTARGS goes into the
1089 environment value "bootargs".
1091 CONFIG_RAMBOOT and CONFIG_NFSBOOT
1092 The value of these goes into the environment as
1093 "ramboot" and "nfsboot" respectively, and can be used
1094 as a convenience, when switching between booting from
1098 CONFIG_BOOTCOUNT_LIMIT
1099 Implements a mechanism for detecting a repeating reboot
1101 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
1103 CONFIG_BOOTCOUNT_ENV
1104 If no softreset save registers are found on the hardware
1105 "bootcount" is stored in the environment. To prevent a
1106 saveenv on all reboots, the environment variable
1107 "upgrade_available" is used. If "upgrade_available" is
1108 0, "bootcount" is always 0, if "upgrade_available" is
1109 1 "bootcount" is incremented in the environment.
1110 So the Userspace Applikation must set the "upgrade_available"
1111 and "bootcount" variable to 0, if a boot was successfully.
1113 - Pre-Boot Commands:
1116 When this option is #defined, the existence of the
1117 environment variable "preboot" will be checked
1118 immediately before starting the CONFIG_BOOTDELAY
1119 countdown and/or running the auto-boot command resp.
1120 entering interactive mode.
1122 This feature is especially useful when "preboot" is
1123 automatically generated or modified. For an example
1124 see the LWMON board specific code: here "preboot" is
1125 modified when the user holds down a certain
1126 combination of keys on the (special) keyboard when
1129 - Serial Download Echo Mode:
1131 If defined to 1, all characters received during a
1132 serial download (using the "loads" command) are
1133 echoed back. This might be needed by some terminal
1134 emulations (like "cu"), but may as well just take
1135 time on others. This setting #define's the initial
1136 value of the "loads_echo" environment variable.
1138 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
1139 CONFIG_KGDB_BAUDRATE
1140 Select one of the baudrates listed in
1141 CONFIG_SYS_BAUDRATE_TABLE, see below.
1143 - Monitor Functions:
1144 Monitor commands can be included or excluded
1145 from the build by using the #include files
1146 <config_cmd_all.h> and #undef'ing unwanted
1147 commands, or using <config_cmd_default.h>
1148 and augmenting with additional #define's
1149 for wanted commands.
1151 The default command configuration includes all commands
1152 except those marked below with a "*".
1154 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
1155 CONFIG_CMD_ASKENV * ask for env variable
1156 CONFIG_CMD_BDI bdinfo
1157 CONFIG_CMD_BEDBUG * Include BedBug Debugger
1158 CONFIG_CMD_BMP * BMP support
1159 CONFIG_CMD_BSP * Board specific commands
1160 CONFIG_CMD_BOOTD bootd
1161 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
1162 CONFIG_CMD_CACHE * icache, dcache
1163 CONFIG_CMD_CLK * clock command support
1164 CONFIG_CMD_CONSOLE coninfo
1165 CONFIG_CMD_CRC32 * crc32
1166 CONFIG_CMD_DATE * support for RTC, date/time...
1167 CONFIG_CMD_DHCP * DHCP support
1168 CONFIG_CMD_DIAG * Diagnostics
1169 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
1170 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
1171 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
1172 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
1173 CONFIG_CMD_DTT * Digital Therm and Thermostat
1174 CONFIG_CMD_ECHO echo arguments
1175 CONFIG_CMD_EDITENV edit env variable
1176 CONFIG_CMD_EEPROM * EEPROM read/write support
1177 CONFIG_CMD_ELF * bootelf, bootvx
1178 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
1179 CONFIG_CMD_ENV_FLAGS * display details about env flags
1180 CONFIG_CMD_ENV_EXISTS * check existence of env variable
1181 CONFIG_CMD_EXPORTENV * export the environment
1182 CONFIG_CMD_EXT2 * ext2 command support
1183 CONFIG_CMD_EXT4 * ext4 command support
1184 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
1185 that work for multiple fs types
1186 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
1187 CONFIG_CMD_SAVEENV saveenv
1188 CONFIG_CMD_FDC * Floppy Disk Support
1189 CONFIG_CMD_FAT * FAT command support
1190 CONFIG_CMD_FLASH flinfo, erase, protect
1191 CONFIG_CMD_FPGA FPGA device initialization support
1192 CONFIG_CMD_FUSE * Device fuse support
1193 CONFIG_CMD_GETTIME * Get time since boot
1194 CONFIG_CMD_GO * the 'go' command (exec code)
1195 CONFIG_CMD_GREPENV * search environment
1196 CONFIG_CMD_HASH * calculate hash / digest
1197 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
1198 CONFIG_CMD_I2C * I2C serial bus support
1199 CONFIG_CMD_IDE * IDE harddisk support
1200 CONFIG_CMD_IMI iminfo
1201 CONFIG_CMD_IMLS List all images found in NOR flash
1202 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
1203 CONFIG_CMD_IMMAP * IMMR dump support
1204 CONFIG_CMD_IOTRACE * I/O tracing for debugging
1205 CONFIG_CMD_IMPORTENV * import an environment
1206 CONFIG_CMD_INI * import data from an ini file into the env
1207 CONFIG_CMD_IRQ * irqinfo
1208 CONFIG_CMD_ITEST Integer/string test of 2 values
1209 CONFIG_CMD_JFFS2 * JFFS2 Support
1210 CONFIG_CMD_KGDB * kgdb
1211 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
1212 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
1214 CONFIG_CMD_LOADB loadb
1215 CONFIG_CMD_LOADS loads
1216 CONFIG_CMD_MD5SUM * print md5 message digest
1217 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
1218 CONFIG_CMD_MEMINFO * Display detailed memory information
1219 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
1221 CONFIG_CMD_MEMTEST * mtest
1222 CONFIG_CMD_MISC Misc functions like sleep etc
1223 CONFIG_CMD_MMC * MMC memory mapped support
1224 CONFIG_CMD_MII * MII utility commands
1225 CONFIG_CMD_MTDPARTS * MTD partition support
1226 CONFIG_CMD_NAND * NAND support
1227 CONFIG_CMD_NET bootp, tftpboot, rarpboot
1228 CONFIG_CMD_NFS NFS support
1229 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
1230 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
1231 CONFIG_CMD_PCI * pciinfo
1232 CONFIG_CMD_PCMCIA * PCMCIA support
1233 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
1235 CONFIG_CMD_PORTIO * Port I/O
1236 CONFIG_CMD_READ * Read raw data from partition
1237 CONFIG_CMD_REGINFO * Register dump
1238 CONFIG_CMD_RUN run command in env variable
1239 CONFIG_CMD_SANDBOX * sb command to access sandbox features
1240 CONFIG_CMD_SAVES * save S record dump
1241 CONFIG_CMD_SCSI * SCSI Support
1242 CONFIG_CMD_SDRAM * print SDRAM configuration information
1243 (requires CONFIG_CMD_I2C)
1244 CONFIG_CMD_SETGETDCR Support for DCR Register access
1246 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
1247 CONFIG_CMD_SHA1SUM * print sha1 memory digest
1248 (requires CONFIG_CMD_MEMORY)
1249 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
1250 CONFIG_CMD_SOURCE "source" command Support
1251 CONFIG_CMD_SPI * SPI serial bus support
1252 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
1253 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
1254 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
1255 CONFIG_CMD_TIMER * access to the system tick timer
1256 CONFIG_CMD_USB * USB support
1257 CONFIG_CMD_CDP * Cisco Discover Protocol support
1258 CONFIG_CMD_MFSL * Microblaze FSL support
1259 CONFIG_CMD_XIMG Load part of Multi Image
1260 CONFIG_CMD_UUID * Generate random UUID or GUID string
1262 EXAMPLE: If you want all functions except of network
1263 support you can write:
1265 #include "config_cmd_all.h"
1266 #undef CONFIG_CMD_NET
1269 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
1271 Note: Don't enable the "icache" and "dcache" commands
1272 (configuration option CONFIG_CMD_CACHE) unless you know
1273 what you (and your U-Boot users) are doing. Data
1274 cache cannot be enabled on systems like the 8xx or
1275 8260 (where accesses to the IMMR region must be
1276 uncached), and it cannot be disabled on all other
1277 systems where we (mis-) use the data cache to hold an
1278 initial stack and some data.
1281 XXX - this list needs to get updated!
1283 - Regular expression support:
1285 If this variable is defined, U-Boot is linked against
1286 the SLRE (Super Light Regular Expression) library,
1287 which adds regex support to some commands, as for
1288 example "env grep" and "setexpr".
1292 If this variable is defined, U-Boot will use a device tree
1293 to configure its devices, instead of relying on statically
1294 compiled #defines in the board file. This option is
1295 experimental and only available on a few boards. The device
1296 tree is available in the global data as gd->fdt_blob.
1298 U-Boot needs to get its device tree from somewhere. This can
1299 be done using one of the two options below:
1302 If this variable is defined, U-Boot will embed a device tree
1303 binary in its image. This device tree file should be in the
1304 board directory and called <soc>-<board>.dts. The binary file
1305 is then picked up in board_init_f() and made available through
1306 the global data structure as gd->blob.
1309 If this variable is defined, U-Boot will build a device tree
1310 binary. It will be called u-boot.dtb. Architecture-specific
1311 code will locate it at run-time. Generally this works by:
1313 cat u-boot.bin u-boot.dtb >image.bin
1315 and in fact, U-Boot does this for you, creating a file called
1316 u-boot-dtb.bin which is useful in the common case. You can
1317 still use the individual files if you need something more
1322 If this variable is defined, it enables watchdog
1323 support for the SoC. There must be support in the SoC
1324 specific code for a watchdog. For the 8xx and 8260
1325 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1326 register. When supported for a specific SoC is
1327 available, then no further board specific code should
1328 be needed to use it.
1331 When using a watchdog circuitry external to the used
1332 SoC, then define this variable and provide board
1333 specific code for the "hw_watchdog_reset" function.
1335 CONFIG_AT91_HW_WDT_TIMEOUT
1336 specify the timeout in seconds. default 2 seconds.
1339 CONFIG_VERSION_VARIABLE
1340 If this variable is defined, an environment variable
1341 named "ver" is created by U-Boot showing the U-Boot
1342 version as printed by the "version" command.
1343 Any change to this variable will be reverted at the
1348 When CONFIG_CMD_DATE is selected, the type of the RTC
1349 has to be selected, too. Define exactly one of the
1352 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1353 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1354 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1355 CONFIG_RTC_MC146818 - use MC146818 RTC
1356 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1357 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1358 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1359 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1360 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1361 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1362 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1363 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1364 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1367 Note that if the RTC uses I2C, then the I2C interface
1368 must also be configured. See I2C Support, below.
1371 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1373 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1374 chip-ngpio pairs that tell the PCA953X driver the number of
1375 pins supported by a particular chip.
1377 Note that if the GPIO device uses I2C, then the I2C interface
1378 must also be configured. See I2C Support, below.
1381 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1382 accesses and can checksum them or write a list of them out
1383 to memory. See the 'iotrace' command for details. This is
1384 useful for testing device drivers since it can confirm that
1385 the driver behaves the same way before and after a code
1386 change. Currently this is supported on sandbox and arm. To
1387 add support for your architecture, add '#include <iotrace.h>'
1388 to the bottom of arch/<arch>/include/asm/io.h and test.
1390 Example output from the 'iotrace stats' command is below.
1391 Note that if the trace buffer is exhausted, the checksum will
1392 still continue to operate.
1395 Start: 10000000 (buffer start address)
1396 Size: 00010000 (buffer size)
1397 Offset: 00000120 (current buffer offset)
1398 Output: 10000120 (start + offset)
1399 Count: 00000018 (number of trace records)
1400 CRC32: 9526fb66 (CRC32 of all trace records)
1402 - Timestamp Support:
1404 When CONFIG_TIMESTAMP is selected, the timestamp
1405 (date and time) of an image is printed by image
1406 commands like bootm or iminfo. This option is
1407 automatically enabled when you select CONFIG_CMD_DATE .
1409 - Partition Labels (disklabels) Supported:
1410 Zero or more of the following:
1411 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1412 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1413 Intel architecture, USB sticks, etc.
1414 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1415 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1416 bootloader. Note 2TB partition limit; see
1418 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1420 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1421 CONFIG_CMD_SCSI) you must configure support for at
1422 least one non-MTD partition type as well.
1425 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1426 board configurations files but used nowhere!
1428 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1429 be performed by calling the function
1430 ide_set_reset(int reset)
1431 which has to be defined in a board specific file
1436 Set this to enable ATAPI support.
1441 Set this to enable support for disks larger than 137GB
1442 Also look at CONFIG_SYS_64BIT_LBA.
1443 Whithout these , LBA48 support uses 32bit variables and will 'only'
1444 support disks up to 2.1TB.
1446 CONFIG_SYS_64BIT_LBA:
1447 When enabled, makes the IDE subsystem use 64bit sector addresses.
1451 At the moment only there is only support for the
1452 SYM53C8XX SCSI controller; define
1453 CONFIG_SCSI_SYM53C8XX to enable it.
1455 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1456 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1457 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1458 maximum numbers of LUNs, SCSI ID's and target
1460 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1462 The environment variable 'scsidevs' is set to the number of
1463 SCSI devices found during the last scan.
1465 - NETWORK Support (PCI):
1467 Support for Intel 8254x/8257x gigabit chips.
1470 Utility code for direct access to the SPI bus on Intel 8257x.
1471 This does not do anything useful unless you set at least one
1472 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1474 CONFIG_E1000_SPI_GENERIC
1475 Allow generic access to the SPI bus on the Intel 8257x, for
1476 example with the "sspi" command.
1479 Management command for E1000 devices. When used on devices
1480 with SPI support you can reprogram the EEPROM from U-Boot.
1482 CONFIG_E1000_FALLBACK_MAC
1483 default MAC for empty EEPROM after production.
1486 Support for Intel 82557/82559/82559ER chips.
1487 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1488 write routine for first time initialisation.
1491 Support for Digital 2114x chips.
1492 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1493 modem chip initialisation (KS8761/QS6611).
1496 Support for National dp83815 chips.
1499 Support for National dp8382[01] gigabit chips.
1501 - NETWORK Support (other):
1503 CONFIG_DRIVER_AT91EMAC
1504 Support for AT91RM9200 EMAC.
1507 Define this to use reduced MII inteface
1509 CONFIG_DRIVER_AT91EMAC_QUIET
1510 If this defined, the driver is quiet.
1511 The driver doen't show link status messages.
1513 CONFIG_CALXEDA_XGMAC
1514 Support for the Calxeda XGMAC device
1517 Support for SMSC's LAN91C96 chips.
1519 CONFIG_LAN91C96_BASE
1520 Define this to hold the physical address
1521 of the LAN91C96's I/O space
1523 CONFIG_LAN91C96_USE_32_BIT
1524 Define this to enable 32 bit addressing
1527 Support for SMSC's LAN91C111 chip
1529 CONFIG_SMC91111_BASE
1530 Define this to hold the physical address
1531 of the device (I/O space)
1533 CONFIG_SMC_USE_32_BIT
1534 Define this if data bus is 32 bits
1536 CONFIG_SMC_USE_IOFUNCS
1537 Define this to use i/o functions instead of macros
1538 (some hardware wont work with macros)
1540 CONFIG_DRIVER_TI_EMAC
1541 Support for davinci emac
1543 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1544 Define this if you have more then 3 PHYs.
1547 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1549 CONFIG_FTGMAC100_EGIGA
1550 Define this to use GE link update with gigabit PHY.
1551 Define this if FTGMAC100 is connected to gigabit PHY.
1552 If your system has 10/100 PHY only, it might not occur
1553 wrong behavior. Because PHY usually return timeout or
1554 useless data when polling gigabit status and gigabit
1555 control registers. This behavior won't affect the
1556 correctnessof 10/100 link speed update.
1559 Support for SMSC's LAN911x and LAN921x chips
1562 Define this to hold the physical address
1563 of the device (I/O space)
1565 CONFIG_SMC911X_32_BIT
1566 Define this if data bus is 32 bits
1568 CONFIG_SMC911X_16_BIT
1569 Define this if data bus is 16 bits. If your processor
1570 automatically converts one 32 bit word to two 16 bit
1571 words you may also try CONFIG_SMC911X_32_BIT.
1574 Support for Renesas on-chip Ethernet controller
1576 CONFIG_SH_ETHER_USE_PORT
1577 Define the number of ports to be used
1579 CONFIG_SH_ETHER_PHY_ADDR
1580 Define the ETH PHY's address
1582 CONFIG_SH_ETHER_CACHE_WRITEBACK
1583 If this option is set, the driver enables cache flush.
1587 Support for PWM modul on the imx6.
1591 Support TPM devices.
1594 Support for i2c bus TPM devices. Only one device
1595 per system is supported at this time.
1597 CONFIG_TPM_TIS_I2C_BUS_NUMBER
1598 Define the the i2c bus number for the TPM device
1600 CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1601 Define the TPM's address on the i2c bus
1603 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1604 Define the burst count bytes upper limit
1606 CONFIG_TPM_ATMEL_TWI
1607 Support for Atmel TWI TPM device. Requires I2C support.
1610 Support for generic parallel port TPM devices. Only one device
1611 per system is supported at this time.
1613 CONFIG_TPM_TIS_BASE_ADDRESS
1614 Base address where the generic TPM device is mapped
1615 to. Contemporary x86 systems usually map it at
1619 Add tpm monitor functions.
1620 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1621 provides monitor access to authorized functions.
1624 Define this to enable the TPM support library which provides
1625 functional interfaces to some TPM commands.
1626 Requires support for a TPM device.
1628 CONFIG_TPM_AUTH_SESSIONS
1629 Define this to enable authorized functions in the TPM library.
1630 Requires CONFIG_TPM and CONFIG_SHA1.
1633 At the moment only the UHCI host controller is
1634 supported (PIP405, MIP405, MPC5200); define
1635 CONFIG_USB_UHCI to enable it.
1636 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1637 and define CONFIG_USB_STORAGE to enable the USB
1640 Supported are USB Keyboards and USB Floppy drives
1642 MPC5200 USB requires additional defines:
1644 for 528 MHz Clock: 0x0001bbbb
1648 for differential drivers: 0x00001000
1649 for single ended drivers: 0x00005000
1650 for differential drivers on PSC3: 0x00000100
1651 for single ended drivers on PSC3: 0x00004100
1652 CONFIG_SYS_USB_EVENT_POLL
1653 May be defined to allow interrupt polling
1654 instead of using asynchronous interrupts
1656 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1657 txfilltuning field in the EHCI controller on reset.
1659 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1660 HW module registers.
1663 Define the below if you wish to use the USB console.
1664 Once firmware is rebuilt from a serial console issue the
1665 command "setenv stdin usbtty; setenv stdout usbtty" and
1666 attach your USB cable. The Unix command "dmesg" should print
1667 it has found a new device. The environment variable usbtty
1668 can be set to gserial or cdc_acm to enable your device to
1669 appear to a USB host as a Linux gserial device or a
1670 Common Device Class Abstract Control Model serial device.
1671 If you select usbtty = gserial you should be able to enumerate
1673 # modprobe usbserial vendor=0xVendorID product=0xProductID
1674 else if using cdc_acm, simply setting the environment
1675 variable usbtty to be cdc_acm should suffice. The following
1676 might be defined in YourBoardName.h
1679 Define this to build a UDC device
1682 Define this to have a tty type of device available to
1683 talk to the UDC device
1686 Define this to enable the high speed support for usb
1687 device and usbtty. If this feature is enabled, a routine
1688 int is_usbd_high_speed(void)
1689 also needs to be defined by the driver to dynamically poll
1690 whether the enumeration has succeded at high speed or full
1693 CONFIG_SYS_CONSOLE_IS_IN_ENV
1694 Define this if you want stdin, stdout &/or stderr to
1698 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1699 Derive USB clock from external clock "blah"
1700 - CONFIG_SYS_USB_EXTC_CLK 0x02
1702 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1703 Derive USB clock from brgclk
1704 - CONFIG_SYS_USB_BRG_CLK 0x04
1706 If you have a USB-IF assigned VendorID then you may wish to
1707 define your own vendor specific values either in BoardName.h
1708 or directly in usbd_vendor_info.h. If you don't define
1709 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1710 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1711 should pretend to be a Linux device to it's target host.
1713 CONFIG_USBD_MANUFACTURER
1714 Define this string as the name of your company for
1715 - CONFIG_USBD_MANUFACTURER "my company"
1717 CONFIG_USBD_PRODUCT_NAME
1718 Define this string as the name of your product
1719 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1721 CONFIG_USBD_VENDORID
1722 Define this as your assigned Vendor ID from the USB
1723 Implementors Forum. This *must* be a genuine Vendor ID
1724 to avoid polluting the USB namespace.
1725 - CONFIG_USBD_VENDORID 0xFFFF
1727 CONFIG_USBD_PRODUCTID
1728 Define this as the unique Product ID
1730 - CONFIG_USBD_PRODUCTID 0xFFFF
1732 - ULPI Layer Support:
1733 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1734 the generic ULPI layer. The generic layer accesses the ULPI PHY
1735 via the platform viewport, so you need both the genric layer and
1736 the viewport enabled. Currently only Chipidea/ARC based
1737 viewport is supported.
1738 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1739 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1740 If your ULPI phy needs a different reference clock than the
1741 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1742 the appropriate value in Hz.
1745 The MMC controller on the Intel PXA is supported. To
1746 enable this define CONFIG_MMC. The MMC can be
1747 accessed from the boot prompt by mapping the device
1748 to physical memory similar to flash. Command line is
1749 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1750 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1753 Support for Renesas on-chip MMCIF controller
1755 CONFIG_SH_MMCIF_ADDR
1756 Define the base address of MMCIF registers
1759 Define the clock frequency for MMCIF
1762 Enable the generic MMC driver
1764 CONFIG_SUPPORT_EMMC_BOOT
1765 Enable some additional features of the eMMC boot partitions.
1767 CONFIG_SUPPORT_EMMC_RPMB
1768 Enable the commands for reading, writing and programming the
1769 key for the Replay Protection Memory Block partition in eMMC.
1771 - USB Device Firmware Update (DFU) class support:
1773 This enables the USB portion of the DFU USB class
1776 This enables the command "dfu" which is used to have
1777 U-Boot create a DFU class device via USB. This command
1778 requires that the "dfu_alt_info" environment variable be
1779 set and define the alt settings to expose to the host.
1782 This enables support for exposing (e)MMC devices via DFU.
1785 This enables support for exposing NAND devices via DFU.
1788 This enables support for exposing RAM via DFU.
1789 Note: DFU spec refer to non-volatile memory usage, but
1790 allow usages beyond the scope of spec - here RAM usage,
1791 one that would help mostly the developer.
1793 CONFIG_SYS_DFU_DATA_BUF_SIZE
1794 Dfu transfer uses a buffer before writing data to the
1795 raw storage device. Make the size (in bytes) of this buffer
1796 configurable. The size of this buffer is also configurable
1797 through the "dfu_bufsiz" environment variable.
1799 CONFIG_SYS_DFU_MAX_FILE_SIZE
1800 When updating files rather than the raw storage device,
1801 we use a static buffer to copy the file into and then write
1802 the buffer once we've been given the whole file. Define
1803 this to the maximum filesize (in bytes) for the buffer.
1804 Default is 4 MiB if undefined.
1806 DFU_DEFAULT_POLL_TIMEOUT
1807 Poll timeout [ms], is the timeout a device can send to the
1808 host. The host must wait for this timeout before sending
1809 a subsequent DFU_GET_STATUS request to the device.
1811 DFU_MANIFEST_POLL_TIMEOUT
1812 Poll timeout [ms], which the device sends to the host when
1813 entering dfuMANIFEST state. Host waits this timeout, before
1814 sending again an USB request to the device.
1816 - USB Device Android Fastboot support:
1818 This enables the command "fastboot" which enables the Android
1819 fastboot mode for the platform's USB device. Fastboot is a USB
1820 protocol for downloading images, flashing and device control
1821 used on Android devices.
1822 See doc/README.android-fastboot for more information.
1824 CONFIG_ANDROID_BOOT_IMAGE
1825 This enables support for booting images which use the Android
1826 image format header.
1828 CONFIG_USB_FASTBOOT_BUF_ADDR
1829 The fastboot protocol requires a large memory buffer for
1830 downloads. Define this to the starting RAM address to use for
1833 CONFIG_USB_FASTBOOT_BUF_SIZE
1834 The fastboot protocol requires a large memory buffer for
1835 downloads. This buffer should be as large as possible for a
1836 platform. Define this to the size available RAM for fastboot.
1838 CONFIG_FASTBOOT_FLASH
1839 The fastboot protocol includes a "flash" command for writing
1840 the downloaded image to a non-volatile storage device. Define
1841 this to enable the "fastboot flash" command.
1843 CONFIG_FASTBOOT_FLASH_MMC_DEV
1844 The fastboot "flash" command requires additional information
1845 regarding the non-volatile storage device. Define this to
1846 the eMMC device that fastboot should use to store the image.
1848 CONFIG_FASTBOOT_GPT_NAME
1849 The fastboot "flash" command supports writing the downloaded
1850 image to the Protective MBR and the Primary GUID Partition
1851 Table. (Additionally, this downloaded image is post-processed
1852 to generate and write the Backup GUID Partition Table.)
1853 This occurs when the specified "partition name" on the
1854 "fastboot flash" command line matches this value.
1855 Default is GPT_ENTRY_NAME (currently "gpt") if undefined.
1857 - Journaling Flash filesystem support:
1858 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1859 CONFIG_JFFS2_NAND_DEV
1860 Define these for a default partition on a NAND device
1862 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1863 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1864 Define these for a default partition on a NOR device
1866 CONFIG_SYS_JFFS_CUSTOM_PART
1867 Define this to create an own partition. You have to provide a
1868 function struct part_info* jffs2_part_info(int part_num)
1870 If you define only one JFFS2 partition you may also want to
1871 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1872 to disable the command chpart. This is the default when you
1873 have not defined a custom partition
1875 - FAT(File Allocation Table) filesystem write function support:
1878 Define this to enable support for saving memory data as a
1879 file in FAT formatted partition.
1881 This will also enable the command "fatwrite" enabling the
1882 user to write files to FAT.
1884 CBFS (Coreboot Filesystem) support
1887 Define this to enable support for reading from a Coreboot
1888 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1891 - FAT(File Allocation Table) filesystem cluster size:
1892 CONFIG_FS_FAT_MAX_CLUSTSIZE
1894 Define the max cluster size for fat operations else
1895 a default value of 65536 will be defined.
1900 Define this to enable standard (PC-Style) keyboard
1904 Standard PC keyboard driver with US (is default) and
1905 GERMAN key layout (switch via environment 'keymap=de') support.
1906 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1907 for cfb_console. Supports cursor blinking.
1910 Enables a Chrome OS keyboard using the CROS_EC interface.
1911 This uses CROS_EC to communicate with a second microcontroller
1912 which provides key scans on request.
1917 Define this to enable video support (for output to
1920 CONFIG_VIDEO_CT69000
1922 Enable Chips & Technologies 69000 Video chip
1924 CONFIG_VIDEO_SMI_LYNXEM
1925 Enable Silicon Motion SMI 712/710/810 Video chip. The
1926 video output is selected via environment 'videoout'
1927 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1930 For the CT69000 and SMI_LYNXEM drivers, videomode is
1931 selected via environment 'videomode'. Two different ways
1933 - "videomode=num" 'num' is a standard LiLo mode numbers.
1934 Following standard modes are supported (* is default):
1936 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1937 -------------+---------------------------------------------
1938 8 bits | 0x301* 0x303 0x305 0x161 0x307
1939 15 bits | 0x310 0x313 0x316 0x162 0x319
1940 16 bits | 0x311 0x314 0x317 0x163 0x31A
1941 24 bits | 0x312 0x315 0x318 ? 0x31B
1942 -------------+---------------------------------------------
1943 (i.e. setenv videomode 317; saveenv; reset;)
1945 - "videomode=bootargs" all the video parameters are parsed
1946 from the bootargs. (See drivers/video/videomodes.c)
1949 CONFIG_VIDEO_SED13806
1950 Enable Epson SED13806 driver. This driver supports 8bpp
1951 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1952 or CONFIG_VIDEO_SED13806_16BPP
1955 Enable the Freescale DIU video driver. Reference boards for
1956 SOCs that have a DIU should define this macro to enable DIU
1957 support, and should also define these other macros:
1963 CONFIG_VIDEO_SW_CURSOR
1964 CONFIG_VGA_AS_SINGLE_DEVICE
1966 CONFIG_VIDEO_BMP_LOGO
1968 The DIU driver will look for the 'video-mode' environment
1969 variable, and if defined, enable the DIU as a console during
1970 boot. See the documentation file README.video for a
1971 description of this variable.
1975 Enable the VGA video / BIOS for x86. The alternative if you
1976 are using coreboot is to use the coreboot frame buffer
1983 Define this to enable a custom keyboard support.
1984 This simply calls drv_keyboard_init() which must be
1985 defined in your board-specific files.
1986 The only board using this so far is RBC823.
1988 - LCD Support: CONFIG_LCD
1990 Define this to enable LCD support (for output to LCD
1991 display); also select one of the supported displays
1992 by defining one of these:
1996 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1998 CONFIG_NEC_NL6448AC33:
2000 NEC NL6448AC33-18. Active, color, single scan.
2002 CONFIG_NEC_NL6448BC20
2004 NEC NL6448BC20-08. 6.5", 640x480.
2005 Active, color, single scan.
2007 CONFIG_NEC_NL6448BC33_54
2009 NEC NL6448BC33-54. 10.4", 640x480.
2010 Active, color, single scan.
2014 Sharp 320x240. Active, color, single scan.
2015 It isn't 16x9, and I am not sure what it is.
2017 CONFIG_SHARP_LQ64D341
2019 Sharp LQ64D341 display, 640x480.
2020 Active, color, single scan.
2024 HLD1045 display, 640x480.
2025 Active, color, single scan.
2029 Optrex CBL50840-2 NF-FW 99 22 M5
2031 Hitachi LMG6912RPFC-00T
2035 320x240. Black & white.
2037 Normally display is black on white background; define
2038 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
2040 CONFIG_LCD_ALIGNMENT
2042 Normally the LCD is page-aligned (typically 4KB). If this is
2043 defined then the LCD will be aligned to this value instead.
2044 For ARM it is sometimes useful to use MMU_SECTION_SIZE
2045 here, since it is cheaper to change data cache settings on
2046 a per-section basis.
2048 CONFIG_CONSOLE_SCROLL_LINES
2050 When the console need to be scrolled, this is the number of
2051 lines to scroll by. It defaults to 1. Increasing this makes
2052 the console jump but can help speed up operation when scrolling
2057 Support drawing of RLE8-compressed bitmaps on the LCD.
2061 Enables an 'i2c edid' command which can read EDID
2062 information over I2C from an attached LCD display.
2064 - Splash Screen Support: CONFIG_SPLASH_SCREEN
2066 If this option is set, the environment is checked for
2067 a variable "splashimage". If found, the usual display
2068 of logo, copyright and system information on the LCD
2069 is suppressed and the BMP image at the address
2070 specified in "splashimage" is loaded instead. The
2071 console is redirected to the "nulldev", too. This
2072 allows for a "silent" boot where a splash screen is
2073 loaded very quickly after power-on.
2075 CONFIG_SPLASHIMAGE_GUARD
2077 If this option is set, then U-Boot will prevent the environment
2078 variable "splashimage" from being set to a problematic address
2079 (see README.displaying-bmps).
2080 This option is useful for targets where, due to alignment
2081 restrictions, an improperly aligned BMP image will cause a data
2082 abort. If you think you will not have problems with unaligned
2083 accesses (for example because your toolchain prevents them)
2084 there is no need to set this option.
2086 CONFIG_SPLASH_SCREEN_ALIGN
2088 If this option is set the splash image can be freely positioned
2089 on the screen. Environment variable "splashpos" specifies the
2090 position as "x,y". If a positive number is given it is used as
2091 number of pixel from left/top. If a negative number is given it
2092 is used as number of pixel from right/bottom. You can also
2093 specify 'm' for centering the image.
2096 setenv splashpos m,m
2097 => image at center of screen
2099 setenv splashpos 30,20
2100 => image at x = 30 and y = 20
2102 setenv splashpos -10,m
2103 => vertically centered image
2104 at x = dspWidth - bmpWidth - 9
2106 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
2108 If this option is set, additionally to standard BMP
2109 images, gzipped BMP images can be displayed via the
2110 splashscreen support or the bmp command.
2112 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
2114 If this option is set, 8-bit RLE compressed BMP images
2115 can be displayed via the splashscreen support or the
2118 - Do compressing for memory range:
2121 If this option is set, it would use zlib deflate method
2122 to compress the specified memory at its best effort.
2124 - Compression support:
2127 Enabled by default to support gzip compressed images.
2131 If this option is set, support for bzip2 compressed
2132 images is included. If not, only uncompressed and gzip
2133 compressed images are supported.
2135 NOTE: the bzip2 algorithm requires a lot of RAM, so
2136 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
2141 If this option is set, support for lzma compressed
2144 Note: The LZMA algorithm adds between 2 and 4KB of code and it
2145 requires an amount of dynamic memory that is given by the
2148 (1846 + 768 << (lc + lp)) * sizeof(uint16)
2150 Where lc and lp stand for, respectively, Literal context bits
2151 and Literal pos bits.
2153 This value is upper-bounded by 14MB in the worst case. Anyway,
2154 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
2155 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
2156 a very small buffer.
2158 Use the lzmainfo tool to determinate the lc and lp values and
2159 then calculate the amount of needed dynamic memory (ensuring
2160 the appropriate CONFIG_SYS_MALLOC_LEN value).
2164 If this option is set, support for LZO compressed images
2170 The address of PHY on MII bus.
2172 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
2174 The clock frequency of the MII bus
2178 If this option is set, support for speed/duplex
2179 detection of gigabit PHY is included.
2181 CONFIG_PHY_RESET_DELAY
2183 Some PHY like Intel LXT971A need extra delay after
2184 reset before any MII register access is possible.
2185 For such PHY, set this option to the usec delay
2186 required. (minimum 300usec for LXT971A)
2188 CONFIG_PHY_CMD_DELAY (ppc4xx)
2190 Some PHY like Intel LXT971A need extra delay after
2191 command issued before MII status register can be read
2201 Define a default value for Ethernet address to use
2202 for the respective Ethernet interface, in case this
2203 is not determined automatically.
2208 Define a default value for the IP address to use for
2209 the default Ethernet interface, in case this is not
2210 determined through e.g. bootp.
2211 (Environment variable "ipaddr")
2213 - Server IP address:
2216 Defines a default value for the IP address of a TFTP
2217 server to contact when using the "tftboot" command.
2218 (Environment variable "serverip")
2220 CONFIG_KEEP_SERVERADDR
2222 Keeps the server's MAC address, in the env 'serveraddr'
2223 for passing to bootargs (like Linux's netconsole option)
2225 - Gateway IP address:
2228 Defines a default value for the IP address of the
2229 default router where packets to other networks are
2231 (Environment variable "gatewayip")
2236 Defines a default value for the subnet mask (or
2237 routing prefix) which is used to determine if an IP
2238 address belongs to the local subnet or needs to be
2239 forwarded through a router.
2240 (Environment variable "netmask")
2242 - Multicast TFTP Mode:
2245 Defines whether you want to support multicast TFTP as per
2246 rfc-2090; for example to work with atftp. Lets lots of targets
2247 tftp down the same boot image concurrently. Note: the Ethernet
2248 driver in use must provide a function: mcast() to join/leave a
2251 - BOOTP Recovery Mode:
2252 CONFIG_BOOTP_RANDOM_DELAY
2254 If you have many targets in a network that try to
2255 boot using BOOTP, you may want to avoid that all
2256 systems send out BOOTP requests at precisely the same
2257 moment (which would happen for instance at recovery
2258 from a power failure, when all systems will try to
2259 boot, thus flooding the BOOTP server. Defining
2260 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
2261 inserted before sending out BOOTP requests. The
2262 following delays are inserted then:
2264 1st BOOTP request: delay 0 ... 1 sec
2265 2nd BOOTP request: delay 0 ... 2 sec
2266 3rd BOOTP request: delay 0 ... 4 sec
2268 BOOTP requests: delay 0 ... 8 sec
2270 CONFIG_BOOTP_ID_CACHE_SIZE
2272 BOOTP packets are uniquely identified using a 32-bit ID. The
2273 server will copy the ID from client requests to responses and
2274 U-Boot will use this to determine if it is the destination of
2275 an incoming response. Some servers will check that addresses
2276 aren't in use before handing them out (usually using an ARP
2277 ping) and therefore take up to a few hundred milliseconds to
2278 respond. Network congestion may also influence the time it
2279 takes for a response to make it back to the client. If that
2280 time is too long, U-Boot will retransmit requests. In order
2281 to allow earlier responses to still be accepted after these
2282 retransmissions, U-Boot's BOOTP client keeps a small cache of
2283 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
2284 cache. The default is to keep IDs for up to four outstanding
2285 requests. Increasing this will allow U-Boot to accept offers
2286 from a BOOTP client in networks with unusually high latency.
2288 - DHCP Advanced Options:
2289 You can fine tune the DHCP functionality by defining
2290 CONFIG_BOOTP_* symbols:
2292 CONFIG_BOOTP_SUBNETMASK
2293 CONFIG_BOOTP_GATEWAY
2294 CONFIG_BOOTP_HOSTNAME
2295 CONFIG_BOOTP_NISDOMAIN
2296 CONFIG_BOOTP_BOOTPATH
2297 CONFIG_BOOTP_BOOTFILESIZE
2300 CONFIG_BOOTP_SEND_HOSTNAME
2301 CONFIG_BOOTP_NTPSERVER
2302 CONFIG_BOOTP_TIMEOFFSET
2303 CONFIG_BOOTP_VENDOREX
2304 CONFIG_BOOTP_MAY_FAIL
2306 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2307 environment variable, not the BOOTP server.
2309 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2310 after the configured retry count, the call will fail
2311 instead of starting over. This can be used to fail over
2312 to Link-local IP address configuration if the DHCP server
2315 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2316 serverip from a DHCP server, it is possible that more
2317 than one DNS serverip is offered to the client.
2318 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2319 serverip will be stored in the additional environment
2320 variable "dnsip2". The first DNS serverip is always
2321 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2324 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2325 to do a dynamic update of a DNS server. To do this, they
2326 need the hostname of the DHCP requester.
2327 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2328 of the "hostname" environment variable is passed as
2329 option 12 to the DHCP server.
2331 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2333 A 32bit value in microseconds for a delay between
2334 receiving a "DHCP Offer" and sending the "DHCP Request".
2335 This fixes a problem with certain DHCP servers that don't
2336 respond 100% of the time to a "DHCP request". E.g. On an
2337 AT91RM9200 processor running at 180MHz, this delay needed
2338 to be *at least* 15,000 usec before a Windows Server 2003
2339 DHCP server would reply 100% of the time. I recommend at
2340 least 50,000 usec to be safe. The alternative is to hope
2341 that one of the retries will be successful but note that
2342 the DHCP timeout and retry process takes a longer than
2345 - Link-local IP address negotiation:
2346 Negotiate with other link-local clients on the local network
2347 for an address that doesn't require explicit configuration.
2348 This is especially useful if a DHCP server cannot be guaranteed
2349 to exist in all environments that the device must operate.
2351 See doc/README.link-local for more information.
2354 CONFIG_CDP_DEVICE_ID
2356 The device id used in CDP trigger frames.
2358 CONFIG_CDP_DEVICE_ID_PREFIX
2360 A two character string which is prefixed to the MAC address
2365 A printf format string which contains the ascii name of
2366 the port. Normally is set to "eth%d" which sets
2367 eth0 for the first Ethernet, eth1 for the second etc.
2369 CONFIG_CDP_CAPABILITIES
2371 A 32bit integer which indicates the device capabilities;
2372 0x00000010 for a normal host which does not forwards.
2376 An ascii string containing the version of the software.
2380 An ascii string containing the name of the platform.
2384 A 32bit integer sent on the trigger.
2386 CONFIG_CDP_POWER_CONSUMPTION
2388 A 16bit integer containing the power consumption of the
2389 device in .1 of milliwatts.
2391 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2393 A byte containing the id of the VLAN.
2395 - Status LED: CONFIG_STATUS_LED
2397 Several configurations allow to display the current
2398 status using a LED. For instance, the LED will blink
2399 fast while running U-Boot code, stop blinking as
2400 soon as a reply to a BOOTP request was received, and
2401 start blinking slow once the Linux kernel is running
2402 (supported by a status LED driver in the Linux
2403 kernel). Defining CONFIG_STATUS_LED enables this
2409 The status LED can be connected to a GPIO pin.
2410 In such cases, the gpio_led driver can be used as a
2411 status LED backend implementation. Define CONFIG_GPIO_LED
2412 to include the gpio_led driver in the U-Boot binary.
2414 CONFIG_GPIO_LED_INVERTED_TABLE
2415 Some GPIO connected LEDs may have inverted polarity in which
2416 case the GPIO high value corresponds to LED off state and
2417 GPIO low value corresponds to LED on state.
2418 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2419 with a list of GPIO LEDs that have inverted polarity.
2421 - CAN Support: CONFIG_CAN_DRIVER
2423 Defining CONFIG_CAN_DRIVER enables CAN driver support
2424 on those systems that support this (optional)
2425 feature, like the TQM8xxL modules.
2427 - I2C Support: CONFIG_SYS_I2C
2429 This enable the NEW i2c subsystem, and will allow you to use
2430 i2c commands at the u-boot command line (as long as you set
2431 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2432 based realtime clock chips or other i2c devices. See
2433 common/cmd_i2c.c for a description of the command line
2436 ported i2c driver to the new framework:
2437 - drivers/i2c/soft_i2c.c:
2438 - activate first bus with CONFIG_SYS_I2C_SOFT define
2439 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2440 for defining speed and slave address
2441 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2442 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2443 for defining speed and slave address
2444 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2445 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2446 for defining speed and slave address
2447 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2448 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2449 for defining speed and slave address
2451 - drivers/i2c/fsl_i2c.c:
2452 - activate i2c driver with CONFIG_SYS_I2C_FSL
2453 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2454 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2455 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2457 - If your board supports a second fsl i2c bus, define
2458 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2459 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2460 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2463 - drivers/i2c/tegra_i2c.c:
2464 - activate this driver with CONFIG_SYS_I2C_TEGRA
2465 - This driver adds 4 i2c buses with a fix speed from
2466 100000 and the slave addr 0!
2468 - drivers/i2c/ppc4xx_i2c.c
2469 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2470 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2471 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2473 - drivers/i2c/i2c_mxc.c
2474 - activate this driver with CONFIG_SYS_I2C_MXC
2475 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2476 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2477 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2478 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2479 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2480 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2481 If those defines are not set, default value is 100000
2482 for speed, and 0 for slave.
2484 - drivers/i2c/rcar_i2c.c:
2485 - activate this driver with CONFIG_SYS_I2C_RCAR
2486 - This driver adds 4 i2c buses
2488 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2489 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2490 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2491 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2492 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2493 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2494 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2495 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2496 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2498 - drivers/i2c/sh_i2c.c:
2499 - activate this driver with CONFIG_SYS_I2C_SH
2500 - This driver adds from 2 to 5 i2c buses
2502 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2503 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2504 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2505 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2506 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2507 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2508 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2509 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2510 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2511 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2512 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2513 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2514 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2516 - drivers/i2c/omap24xx_i2c.c
2517 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2518 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2519 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2520 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2521 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2522 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2523 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2524 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2525 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2526 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2527 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2529 - drivers/i2c/zynq_i2c.c
2530 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2531 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2532 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2534 - drivers/i2c/s3c24x0_i2c.c:
2535 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2536 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2537 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2538 with a fix speed from 100000 and the slave addr 0!
2540 - drivers/i2c/ihs_i2c.c
2541 - activate this driver with CONFIG_SYS_I2C_IHS
2542 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2543 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2544 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2545 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2546 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2547 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2548 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2549 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2550 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2551 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2552 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2553 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2557 CONFIG_SYS_NUM_I2C_BUSES
2558 Hold the number of i2c buses you want to use. If you
2559 don't use/have i2c muxes on your i2c bus, this
2560 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2563 CONFIG_SYS_I2C_DIRECT_BUS
2564 define this, if you don't use i2c muxes on your hardware.
2565 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2568 CONFIG_SYS_I2C_MAX_HOPS
2569 define how many muxes are maximal consecutively connected
2570 on one i2c bus. If you not use i2c muxes, omit this
2573 CONFIG_SYS_I2C_BUSES
2574 hold a list of buses you want to use, only used if
2575 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2576 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2577 CONFIG_SYS_NUM_I2C_BUSES = 9:
2579 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2580 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2581 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2582 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2583 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2584 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2585 {1, {I2C_NULL_HOP}}, \
2586 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2587 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2591 bus 0 on adapter 0 without a mux
2592 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2593 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2594 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2595 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2596 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2597 bus 6 on adapter 1 without a mux
2598 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2599 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2601 If you do not have i2c muxes on your board, omit this define.
2603 - Legacy I2C Support: CONFIG_HARD_I2C
2605 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2606 provides the following compelling advantages:
2608 - more than one i2c adapter is usable
2609 - approved multibus support
2610 - better i2c mux support
2612 ** Please consider updating your I2C driver now. **
2614 These enable legacy I2C serial bus commands. Defining
2615 CONFIG_HARD_I2C will include the appropriate I2C driver
2616 for the selected CPU.
2618 This will allow you to use i2c commands at the u-boot
2619 command line (as long as you set CONFIG_CMD_I2C in
2620 CONFIG_COMMANDS) and communicate with i2c based realtime
2621 clock chips. See common/cmd_i2c.c for a description of the
2622 command line interface.
2624 CONFIG_HARD_I2C selects a hardware I2C controller.
2626 There are several other quantities that must also be
2627 defined when you define CONFIG_HARD_I2C.
2629 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2630 to be the frequency (in Hz) at which you wish your i2c bus
2631 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2632 the CPU's i2c node address).
2634 Now, the u-boot i2c code for the mpc8xx
2635 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2636 and so its address should therefore be cleared to 0 (See,
2637 eg, MPC823e User's Manual p.16-473). So, set
2638 CONFIG_SYS_I2C_SLAVE to 0.
2640 CONFIG_SYS_I2C_INIT_MPC5XXX
2642 When a board is reset during an i2c bus transfer
2643 chips might think that the current transfer is still
2644 in progress. Reset the slave devices by sending start
2645 commands until the slave device responds.
2647 That's all that's required for CONFIG_HARD_I2C.
2649 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2650 then the following macros need to be defined (examples are
2651 from include/configs/lwmon.h):
2655 (Optional). Any commands necessary to enable the I2C
2656 controller or configure ports.
2658 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2662 (Only for MPC8260 CPU). The I/O port to use (the code
2663 assumes both bits are on the same port). Valid values
2664 are 0..3 for ports A..D.
2668 The code necessary to make the I2C data line active
2669 (driven). If the data line is open collector, this
2672 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2676 The code necessary to make the I2C data line tri-stated
2677 (inactive). If the data line is open collector, this
2680 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2684 Code that returns true if the I2C data line is high,
2687 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2691 If <bit> is true, sets the I2C data line high. If it
2692 is false, it clears it (low).
2694 eg: #define I2C_SDA(bit) \
2695 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2696 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2700 If <bit> is true, sets the I2C clock line high. If it
2701 is false, it clears it (low).
2703 eg: #define I2C_SCL(bit) \
2704 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2705 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2709 This delay is invoked four times per clock cycle so this
2710 controls the rate of data transfer. The data rate thus
2711 is 1 / (I2C_DELAY * 4). Often defined to be something
2714 #define I2C_DELAY udelay(2)
2716 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2718 If your arch supports the generic GPIO framework (asm/gpio.h),
2719 then you may alternatively define the two GPIOs that are to be
2720 used as SCL / SDA. Any of the previous I2C_xxx macros will
2721 have GPIO-based defaults assigned to them as appropriate.
2723 You should define these to the GPIO value as given directly to
2724 the generic GPIO functions.
2726 CONFIG_SYS_I2C_INIT_BOARD
2728 When a board is reset during an i2c bus transfer
2729 chips might think that the current transfer is still
2730 in progress. On some boards it is possible to access
2731 the i2c SCLK line directly, either by using the
2732 processor pin as a GPIO or by having a second pin
2733 connected to the bus. If this option is defined a
2734 custom i2c_init_board() routine in boards/xxx/board.c
2735 is run early in the boot sequence.
2737 CONFIG_SYS_I2C_BOARD_LATE_INIT
2739 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2740 defined a custom i2c_board_late_init() routine in
2741 boards/xxx/board.c is run AFTER the operations in i2c_init()
2742 is completed. This callpoint can be used to unreset i2c bus
2743 using CPU i2c controller register accesses for CPUs whose i2c
2744 controller provide such a method. It is called at the end of
2745 i2c_init() to allow i2c_init operations to setup the i2c bus
2746 controller on the CPU (e.g. setting bus speed & slave address).
2748 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2750 This option enables configuration of bi_iic_fast[] flags
2751 in u-boot bd_info structure based on u-boot environment
2752 variable "i2cfast". (see also i2cfast)
2754 CONFIG_I2C_MULTI_BUS
2756 This option allows the use of multiple I2C buses, each of which
2757 must have a controller. At any point in time, only one bus is
2758 active. To switch to a different bus, use the 'i2c dev' command.
2759 Note that bus numbering is zero-based.
2761 CONFIG_SYS_I2C_NOPROBES
2763 This option specifies a list of I2C devices that will be skipped
2764 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2765 is set, specify a list of bus-device pairs. Otherwise, specify
2766 a 1D array of device addresses
2769 #undef CONFIG_I2C_MULTI_BUS
2770 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2772 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2774 #define CONFIG_I2C_MULTI_BUS
2775 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2777 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2779 CONFIG_SYS_SPD_BUS_NUM
2781 If defined, then this indicates the I2C bus number for DDR SPD.
2782 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2784 CONFIG_SYS_RTC_BUS_NUM
2786 If defined, then this indicates the I2C bus number for the RTC.
2787 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2789 CONFIG_SYS_DTT_BUS_NUM
2791 If defined, then this indicates the I2C bus number for the DTT.
2792 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2794 CONFIG_SYS_I2C_DTT_ADDR:
2796 If defined, specifies the I2C address of the DTT device.
2797 If not defined, then U-Boot uses predefined value for
2798 specified DTT device.
2800 CONFIG_SOFT_I2C_READ_REPEATED_START
2802 defining this will force the i2c_read() function in
2803 the soft_i2c driver to perform an I2C repeated start
2804 between writing the address pointer and reading the
2805 data. If this define is omitted the default behaviour
2806 of doing a stop-start sequence will be used. Most I2C
2807 devices can use either method, but some require one or
2810 - SPI Support: CONFIG_SPI
2812 Enables SPI driver (so far only tested with
2813 SPI EEPROM, also an instance works with Crystal A/D and
2814 D/As on the SACSng board)
2818 Enables the driver for SPI controller on SuperH. Currently
2819 only SH7757 is supported.
2823 Enables extended (16-bit) SPI EEPROM addressing.
2824 (symmetrical to CONFIG_I2C_X)
2828 Enables a software (bit-bang) SPI driver rather than
2829 using hardware support. This is a general purpose
2830 driver that only requires three general I/O port pins
2831 (two outputs, one input) to function. If this is
2832 defined, the board configuration must define several
2833 SPI configuration items (port pins to use, etc). For
2834 an example, see include/configs/sacsng.h.
2838 Enables a hardware SPI driver for general-purpose reads
2839 and writes. As with CONFIG_SOFT_SPI, the board configuration
2840 must define a list of chip-select function pointers.
2841 Currently supported on some MPC8xxx processors. For an
2842 example, see include/configs/mpc8349emds.h.
2846 Enables the driver for the SPI controllers on i.MX and MXC
2847 SoCs. Currently i.MX31/35/51 are supported.
2849 CONFIG_SYS_SPI_MXC_WAIT
2850 Timeout for waiting until spi transfer completed.
2851 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2853 - FPGA Support: CONFIG_FPGA
2855 Enables FPGA subsystem.
2857 CONFIG_FPGA_<vendor>
2859 Enables support for specific chip vendors.
2862 CONFIG_FPGA_<family>
2864 Enables support for FPGA family.
2865 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2869 Specify the number of FPGA devices to support.
2871 CONFIG_CMD_FPGA_LOADMK
2873 Enable support for fpga loadmk command
2875 CONFIG_CMD_FPGA_LOADP
2877 Enable support for fpga loadp command - load partial bitstream
2879 CONFIG_CMD_FPGA_LOADBP
2881 Enable support for fpga loadbp command - load partial bitstream
2884 CONFIG_SYS_FPGA_PROG_FEEDBACK
2886 Enable printing of hash marks during FPGA configuration.
2888 CONFIG_SYS_FPGA_CHECK_BUSY
2890 Enable checks on FPGA configuration interface busy
2891 status by the configuration function. This option
2892 will require a board or device specific function to
2897 If defined, a function that provides delays in the FPGA
2898 configuration driver.
2900 CONFIG_SYS_FPGA_CHECK_CTRLC
2901 Allow Control-C to interrupt FPGA configuration
2903 CONFIG_SYS_FPGA_CHECK_ERROR
2905 Check for configuration errors during FPGA bitfile
2906 loading. For example, abort during Virtex II
2907 configuration if the INIT_B line goes low (which
2908 indicated a CRC error).
2910 CONFIG_SYS_FPGA_WAIT_INIT
2912 Maximum time to wait for the INIT_B line to de-assert
2913 after PROB_B has been de-asserted during a Virtex II
2914 FPGA configuration sequence. The default time is 500
2917 CONFIG_SYS_FPGA_WAIT_BUSY
2919 Maximum time to wait for BUSY to de-assert during
2920 Virtex II FPGA configuration. The default is 5 ms.
2922 CONFIG_SYS_FPGA_WAIT_CONFIG
2924 Time to wait after FPGA configuration. The default is
2927 - Configuration Management:
2930 Some SoCs need special image types (e.g. U-Boot binary
2931 with a special header) as build targets. By defining
2932 CONFIG_BUILD_TARGET in the SoC / board header, this
2933 special image will be automatically built upon calling
2938 If defined, this string will be added to the U-Boot
2939 version information (U_BOOT_VERSION)
2941 - Vendor Parameter Protection:
2943 U-Boot considers the values of the environment
2944 variables "serial#" (Board Serial Number) and
2945 "ethaddr" (Ethernet Address) to be parameters that
2946 are set once by the board vendor / manufacturer, and
2947 protects these variables from casual modification by
2948 the user. Once set, these variables are read-only,
2949 and write or delete attempts are rejected. You can
2950 change this behaviour:
2952 If CONFIG_ENV_OVERWRITE is #defined in your config
2953 file, the write protection for vendor parameters is
2954 completely disabled. Anybody can change or delete
2957 Alternatively, if you #define _both_ CONFIG_ETHADDR
2958 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2959 Ethernet address is installed in the environment,
2960 which can be changed exactly ONCE by the user. [The
2961 serial# is unaffected by this, i. e. it remains
2964 The same can be accomplished in a more flexible way
2965 for any variable by configuring the type of access
2966 to allow for those variables in the ".flags" variable
2967 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2972 Define this variable to enable the reservation of
2973 "protected RAM", i. e. RAM which is not overwritten
2974 by U-Boot. Define CONFIG_PRAM to hold the number of
2975 kB you want to reserve for pRAM. You can overwrite
2976 this default value by defining an environment
2977 variable "pram" to the number of kB you want to
2978 reserve. Note that the board info structure will
2979 still show the full amount of RAM. If pRAM is
2980 reserved, a new environment variable "mem" will
2981 automatically be defined to hold the amount of
2982 remaining RAM in a form that can be passed as boot
2983 argument to Linux, for instance like that:
2985 setenv bootargs ... mem=\${mem}
2988 This way you can tell Linux not to use this memory,
2989 either, which results in a memory region that will
2990 not be affected by reboots.
2992 *WARNING* If your board configuration uses automatic
2993 detection of the RAM size, you must make sure that
2994 this memory test is non-destructive. So far, the
2995 following board configurations are known to be
2998 IVMS8, IVML24, SPD8xx, TQM8xxL,
2999 HERMES, IP860, RPXlite, LWMON,
3002 - Access to physical memory region (> 4GB)
3003 Some basic support is provided for operations on memory not
3004 normally accessible to U-Boot - e.g. some architectures
3005 support access to more than 4GB of memory on 32-bit
3006 machines using physical address extension or similar.
3007 Define CONFIG_PHYSMEM to access this basic support, which
3008 currently only supports clearing the memory.
3013 Define this variable to stop the system in case of a
3014 fatal error, so that you have to reset it manually.
3015 This is probably NOT a good idea for an embedded
3016 system where you want the system to reboot
3017 automatically as fast as possible, but it may be
3018 useful during development since you can try to debug
3019 the conditions that lead to the situation.
3021 CONFIG_NET_RETRY_COUNT
3023 This variable defines the number of retries for
3024 network operations like ARP, RARP, TFTP, or BOOTP
3025 before giving up the operation. If not defined, a
3026 default value of 5 is used.
3030 Timeout waiting for an ARP reply in milliseconds.
3034 Timeout in milliseconds used in NFS protocol.
3035 If you encounter "ERROR: Cannot umount" in nfs command,
3036 try longer timeout such as
3037 #define CONFIG_NFS_TIMEOUT 10000UL
3039 - Command Interpreter:
3040 CONFIG_AUTO_COMPLETE
3042 Enable auto completion of commands using TAB.
3044 CONFIG_SYS_PROMPT_HUSH_PS2
3046 This defines the secondary prompt string, which is
3047 printed when the command interpreter needs more input
3048 to complete a command. Usually "> ".
3052 In the current implementation, the local variables
3053 space and global environment variables space are
3054 separated. Local variables are those you define by
3055 simply typing `name=value'. To access a local
3056 variable later on, you have write `$name' or
3057 `${name}'; to execute the contents of a variable
3058 directly type `$name' at the command prompt.
3060 Global environment variables are those you use
3061 setenv/printenv to work with. To run a command stored
3062 in such a variable, you need to use the run command,
3063 and you must not use the '$' sign to access them.
3065 To store commands and special characters in a
3066 variable, please use double quotation marks
3067 surrounding the whole text of the variable, instead
3068 of the backslashes before semicolons and special
3071 - Command Line Editing and History:
3072 CONFIG_CMDLINE_EDITING
3074 Enable editing and History functions for interactive
3075 command line input operations
3077 - Default Environment:
3078 CONFIG_EXTRA_ENV_SETTINGS
3080 Define this to contain any number of null terminated
3081 strings (variable = value pairs) that will be part of
3082 the default environment compiled into the boot image.
3084 For example, place something like this in your
3085 board's config file:
3087 #define CONFIG_EXTRA_ENV_SETTINGS \
3091 Warning: This method is based on knowledge about the
3092 internal format how the environment is stored by the
3093 U-Boot code. This is NOT an official, exported
3094 interface! Although it is unlikely that this format
3095 will change soon, there is no guarantee either.
3096 You better know what you are doing here.
3098 Note: overly (ab)use of the default environment is
3099 discouraged. Make sure to check other ways to preset
3100 the environment like the "source" command or the
3103 CONFIG_ENV_VARS_UBOOT_CONFIG
3105 Define this in order to add variables describing the
3106 U-Boot build configuration to the default environment.
3107 These will be named arch, cpu, board, vendor, and soc.
3109 Enabling this option will cause the following to be defined:
3117 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
3119 Define this in order to add variables describing certain
3120 run-time determined information about the hardware to the
3121 environment. These will be named board_name, board_rev.
3123 CONFIG_DELAY_ENVIRONMENT
3125 Normally the environment is loaded when the board is
3126 initialised so that it is available to U-Boot. This inhibits
3127 that so that the environment is not available until
3128 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
3129 this is instead controlled by the value of
3130 /config/load-environment.
3132 - DataFlash Support:
3133 CONFIG_HAS_DATAFLASH
3135 Defining this option enables DataFlash features and
3136 allows to read/write in Dataflash via the standard
3139 - Serial Flash support
3142 Defining this option enables SPI flash commands
3143 'sf probe/read/write/erase/update'.
3145 Usage requires an initial 'probe' to define the serial
3146 flash parameters, followed by read/write/erase/update
3149 The following defaults may be provided by the platform
3150 to handle the common case when only a single serial
3151 flash is present on the system.
3153 CONFIG_SF_DEFAULT_BUS Bus identifier
3154 CONFIG_SF_DEFAULT_CS Chip-select
3155 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
3156 CONFIG_SF_DEFAULT_SPEED in Hz
3160 Define this option to include a destructive SPI flash
3163 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
3165 Define this option to use the Bank addr/Extended addr
3166 support on SPI flashes which has size > 16Mbytes.
3168 CONFIG_SF_DUAL_FLASH Dual flash memories
3170 Define this option to use dual flash support where two flash
3171 memories can be connected with a given cs line.
3172 Currently Xilinx Zynq qspi supports these type of connections.
3174 CONFIG_SYS_SPI_ST_ENABLE_WP_PIN
3175 enable the W#/Vpp signal to disable writing to the status
3176 register on ST MICRON flashes like the N25Q128.
3177 The status register write enable/disable bit, combined with
3178 the W#/VPP signal provides hardware data protection for the
3179 device as follows: When the enable/disable bit is set to 1,
3180 and the W#/VPP signal is driven LOW, the status register
3181 nonvolatile bits become read-only and the WRITE STATUS REGISTER
3182 operation will not execute. The only way to exit this
3183 hardware-protected mode is to drive W#/VPP HIGH.
3185 - SystemACE Support:
3188 Adding this option adds support for Xilinx SystemACE
3189 chips attached via some sort of local bus. The address
3190 of the chip must also be defined in the
3191 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
3193 #define CONFIG_SYSTEMACE
3194 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
3196 When SystemACE support is added, the "ace" device type
3197 becomes available to the fat commands, i.e. fatls.
3199 - TFTP Fixed UDP Port:
3202 If this is defined, the environment variable tftpsrcp
3203 is used to supply the TFTP UDP source port value.
3204 If tftpsrcp isn't defined, the normal pseudo-random port
3205 number generator is used.
3207 Also, the environment variable tftpdstp is used to supply
3208 the TFTP UDP destination port value. If tftpdstp isn't
3209 defined, the normal port 69 is used.
3211 The purpose for tftpsrcp is to allow a TFTP server to
3212 blindly start the TFTP transfer using the pre-configured
3213 target IP address and UDP port. This has the effect of
3214 "punching through" the (Windows XP) firewall, allowing
3215 the remainder of the TFTP transfer to proceed normally.
3216 A better solution is to properly configure the firewall,
3217 but sometimes that is not allowed.
3222 This enables a generic 'hash' command which can produce
3223 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
3227 Enable the hash verify command (hash -v). This adds to code
3230 CONFIG_SHA1 - This option enables support of hashing using SHA1
3231 algorithm. The hash is calculated in software.
3232 CONFIG_SHA256 - This option enables support of hashing using
3233 SHA256 algorithm. The hash is calculated in software.
3234 CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
3235 for SHA1/SHA256 hashing.
3236 This affects the 'hash' command and also the
3237 hash_lookup_algo() function.
3238 CONFIG_SHA_PROG_HW_ACCEL - This option enables
3239 hardware-acceleration for SHA1/SHA256 progressive hashing.
3240 Data can be streamed in a block at a time and the hashing
3241 is performed in hardware.
3243 Note: There is also a sha1sum command, which should perhaps
3244 be deprecated in favour of 'hash sha1'.
3246 - Freescale i.MX specific commands:
3247 CONFIG_CMD_HDMIDETECT
3248 This enables 'hdmidet' command which returns true if an
3249 HDMI monitor is detected. This command is i.MX 6 specific.
3252 This enables the 'bmode' (bootmode) command for forcing
3253 a boot from specific media.
3255 This is useful for forcing the ROM's usb downloader to
3256 activate upon a watchdog reset which is nice when iterating
3257 on U-Boot. Using the reset button or running bmode normal
3258 will set it back to normal. This command currently
3259 supports i.MX53 and i.MX6.
3264 This enables the RSA algorithm used for FIT image verification
3265 in U-Boot. See doc/uImage.FIT/signature.txt for more information.
3267 The Modular Exponentiation algorithm in RSA is implemented using
3268 driver model. So CONFIG_DM needs to be enabled by default for this
3269 library to function.
3271 The signing part is build into mkimage regardless of this
3272 option. The software based modular exponentiation is built into
3273 mkimage irrespective of this option.
3275 - bootcount support:
3276 CONFIG_BOOTCOUNT_LIMIT
3278 This enables the bootcounter support, see:
3279 http://www.denx.de/wiki/DULG/UBootBootCountLimit
3282 enable special bootcounter support on at91sam9xe based boards.
3284 enable special bootcounter support on blackfin based boards.
3286 enable special bootcounter support on da850 based boards.
3287 CONFIG_BOOTCOUNT_RAM
3288 enable support for the bootcounter in RAM
3289 CONFIG_BOOTCOUNT_I2C
3290 enable support for the bootcounter on an i2c (like RTC) device.
3291 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
3292 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
3294 CONFIG_BOOTCOUNT_ALEN = address len
3296 - Show boot progress:
3297 CONFIG_SHOW_BOOT_PROGRESS
3299 Defining this option allows to add some board-
3300 specific code (calling a user-provided function
3301 "show_boot_progress(int)") that enables you to show
3302 the system's boot progress on some display (for
3303 example, some LED's) on your board. At the moment,
3304 the following checkpoints are implemented:
3306 - Detailed boot stage timing
3308 Define this option to get detailed timing of each stage
3309 of the boot process.
3311 CONFIG_BOOTSTAGE_USER_COUNT
3312 This is the number of available user bootstage records.
3313 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
3314 a new ID will be allocated from this stash. If you exceed
3315 the limit, recording will stop.
3317 CONFIG_BOOTSTAGE_REPORT
3318 Define this to print a report before boot, similar to this:
3320 Timer summary in microseconds:
3323 3,575,678 3,575,678 board_init_f start
3324 3,575,695 17 arch_cpu_init A9
3325 3,575,777 82 arch_cpu_init done
3326 3,659,598 83,821 board_init_r start
3327 3,910,375 250,777 main_loop
3328 29,916,167 26,005,792 bootm_start
3329 30,361,327 445,160 start_kernel
3331 CONFIG_CMD_BOOTSTAGE
3332 Add a 'bootstage' command which supports printing a report
3333 and un/stashing of bootstage data.
3335 CONFIG_BOOTSTAGE_FDT
3336 Stash the bootstage information in the FDT. A root 'bootstage'
3337 node is created with each bootstage id as a child. Each child
3338 has a 'name' property and either 'mark' containing the
3339 mark time in microsecond, or 'accum' containing the
3340 accumulated time for that bootstage id in microseconds.
3345 name = "board_init_f";
3354 Code in the Linux kernel can find this in /proc/devicetree.
3356 Legacy uImage format:
3359 1 common/cmd_bootm.c before attempting to boot an image
3360 -1 common/cmd_bootm.c Image header has bad magic number
3361 2 common/cmd_bootm.c Image header has correct magic number
3362 -2 common/cmd_bootm.c Image header has bad checksum
3363 3 common/cmd_bootm.c Image header has correct checksum
3364 -3 common/cmd_bootm.c Image data has bad checksum
3365 4 common/cmd_bootm.c Image data has correct checksum
3366 -4 common/cmd_bootm.c Image is for unsupported architecture
3367 5 common/cmd_bootm.c Architecture check OK
3368 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
3369 6 common/cmd_bootm.c Image Type check OK
3370 -6 common/cmd_bootm.c gunzip uncompression error
3371 -7 common/cmd_bootm.c Unimplemented compression type
3372 7 common/cmd_bootm.c Uncompression OK
3373 8 common/cmd_bootm.c No uncompress/copy overwrite error
3374 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
3376 9 common/image.c Start initial ramdisk verification
3377 -10 common/image.c Ramdisk header has bad magic number
3378 -11 common/image.c Ramdisk header has bad checksum
3379 10 common/image.c Ramdisk header is OK
3380 -12 common/image.c Ramdisk data has bad checksum
3381 11 common/image.c Ramdisk data has correct checksum
3382 12 common/image.c Ramdisk verification complete, start loading
3383 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3384 13 common/image.c Start multifile image verification
3385 14 common/image.c No initial ramdisk, no multifile, continue.
3387 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3389 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3390 -31 post/post.c POST test failed, detected by post_output_backlog()
3391 -32 post/post.c POST test failed, detected by post_run_single()
3393 34 common/cmd_doc.c before loading a Image from a DOC device
3394 -35 common/cmd_doc.c Bad usage of "doc" command
3395 35 common/cmd_doc.c correct usage of "doc" command
3396 -36 common/cmd_doc.c No boot device
3397 36 common/cmd_doc.c correct boot device
3398 -37 common/cmd_doc.c Unknown Chip ID on boot device
3399 37 common/cmd_doc.c correct chip ID found, device available
3400 -38 common/cmd_doc.c Read Error on boot device
3401 38 common/cmd_doc.c reading Image header from DOC device OK
3402 -39 common/cmd_doc.c Image header has bad magic number
3403 39 common/cmd_doc.c Image header has correct magic number
3404 -40 common/cmd_doc.c Error reading Image from DOC device
3405 40 common/cmd_doc.c Image header has correct magic number
3406 41 common/cmd_ide.c before loading a Image from a IDE device
3407 -42 common/cmd_ide.c Bad usage of "ide" command
3408 42 common/cmd_ide.c correct usage of "ide" command
3409 -43 common/cmd_ide.c No boot device
3410 43 common/cmd_ide.c boot device found
3411 -44 common/cmd_ide.c Device not available
3412 44 common/cmd_ide.c Device available
3413 -45 common/cmd_ide.c wrong partition selected
3414 45 common/cmd_ide.c partition selected
3415 -46 common/cmd_ide.c Unknown partition table
3416 46 common/cmd_ide.c valid partition table found
3417 -47 common/cmd_ide.c Invalid partition type
3418 47 common/cmd_ide.c correct partition type
3419 -48 common/cmd_ide.c Error reading Image Header on boot device
3420 48 common/cmd_ide.c reading Image Header from IDE device OK
3421 -49 common/cmd_ide.c Image header has bad magic number
3422 49 common/cmd_ide.c Image header has correct magic number
3423 -50 common/cmd_ide.c Image header has bad checksum
3424 50 common/cmd_ide.c Image header has correct checksum
3425 -51 common/cmd_ide.c Error reading Image from IDE device
3426 51 common/cmd_ide.c reading Image from IDE device OK
3427 52 common/cmd_nand.c before loading a Image from a NAND device
3428 -53 common/cmd_nand.c Bad usage of "nand" command
3429 53 common/cmd_nand.c correct usage of "nand" command
3430 -54 common/cmd_nand.c No boot device
3431 54 common/cmd_nand.c boot device found
3432 -55 common/cmd_nand.c Unknown Chip ID on boot device
3433 55 common/cmd_nand.c correct chip ID found, device available
3434 -56 common/cmd_nand.c Error reading Image Header on boot device
3435 56 common/cmd_nand.c reading Image Header from NAND device OK
3436 -57 common/cmd_nand.c Image header has bad magic number
3437 57 common/cmd_nand.c Image header has correct magic number
3438 -58 common/cmd_nand.c Error reading Image from NAND device
3439 58 common/cmd_nand.c reading Image from NAND device OK
3441 -60 common/env_common.c Environment has a bad CRC, using default
3443 64 net/eth.c starting with Ethernet configuration.
3444 -64 net/eth.c no Ethernet found.
3445 65 net/eth.c Ethernet found.
3447 -80 common/cmd_net.c usage wrong
3448 80 common/cmd_net.c before calling NetLoop()
3449 -81 common/cmd_net.c some error in NetLoop() occurred
3450 81 common/cmd_net.c NetLoop() back without error
3451 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3452 82 common/cmd_net.c trying automatic boot
3453 83 common/cmd_net.c running "source" command
3454 -83 common/cmd_net.c some error in automatic boot or "source" command
3455 84 common/cmd_net.c end without errors
3460 100 common/cmd_bootm.c Kernel FIT Image has correct format
3461 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3462 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3463 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3464 102 common/cmd_bootm.c Kernel unit name specified
3465 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3466 103 common/cmd_bootm.c Found configuration node
3467 104 common/cmd_bootm.c Got kernel subimage node offset
3468 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3469 105 common/cmd_bootm.c Kernel subimage hash verification OK
3470 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3471 106 common/cmd_bootm.c Architecture check OK
3472 -106 common/cmd_bootm.c Kernel subimage has wrong type
3473 107 common/cmd_bootm.c Kernel subimage type OK
3474 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3475 108 common/cmd_bootm.c Got kernel subimage data/size
3476 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3477 -109 common/cmd_bootm.c Can't get kernel subimage type
3478 -110 common/cmd_bootm.c Can't get kernel subimage comp
3479 -111 common/cmd_bootm.c Can't get kernel subimage os
3480 -112 common/cmd_bootm.c Can't get kernel subimage load address
3481 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3483 120 common/image.c Start initial ramdisk verification
3484 -120 common/image.c Ramdisk FIT image has incorrect format
3485 121 common/image.c Ramdisk FIT image has correct format
3486 122 common/image.c No ramdisk subimage unit name, using configuration
3487 -122 common/image.c Can't get configuration for ramdisk subimage
3488 123 common/image.c Ramdisk unit name specified
3489 -124 common/image.c Can't get ramdisk subimage node offset
3490 125 common/image.c Got ramdisk subimage node offset
3491 -125 common/image.c Ramdisk subimage hash verification failed
3492 126 common/image.c Ramdisk subimage hash verification OK
3493 -126 common/image.c Ramdisk subimage for unsupported architecture
3494 127 common/image.c Architecture check OK
3495 -127 common/image.c Can't get ramdisk subimage data/size
3496 128 common/image.c Got ramdisk subimage data/size
3497 129 common/image.c Can't get ramdisk load address
3498 -129 common/image.c Got ramdisk load address
3500 -130 common/cmd_doc.c Incorrect FIT image format
3501 131 common/cmd_doc.c FIT image format OK
3503 -140 common/cmd_ide.c Incorrect FIT image format
3504 141 common/cmd_ide.c FIT image format OK
3506 -150 common/cmd_nand.c Incorrect FIT image format
3507 151 common/cmd_nand.c FIT image format OK
3509 - legacy image format:
3510 CONFIG_IMAGE_FORMAT_LEGACY
3511 enables the legacy image format support in U-Boot.
3514 enabled if CONFIG_FIT_SIGNATURE is not defined.
3516 CONFIG_DISABLE_IMAGE_LEGACY
3517 disable the legacy image format
3519 This define is introduced, as the legacy image format is
3520 enabled per default for backward compatibility.
3522 - FIT image support:
3524 Enable support for the FIT uImage format.
3526 CONFIG_FIT_BEST_MATCH
3527 When no configuration is explicitly selected, default to the
3528 one whose fdt's compatibility field best matches that of
3529 U-Boot itself. A match is considered "best" if it matches the
3530 most specific compatibility entry of U-Boot's fdt's root node.
3531 The order of entries in the configuration's fdt is ignored.
3533 CONFIG_FIT_SIGNATURE
3534 This option enables signature verification of FIT uImages,
3535 using a hash signed and verified using RSA. If
3536 CONFIG_SHA_PROG_HW_ACCEL is defined, i.e support for progressive
3537 hashing is available using hardware, RSA library will use it.
3538 See doc/uImage.FIT/signature.txt for more details.
3540 WARNING: When relying on signed FIT images with required
3541 signature check the legacy image format is default
3542 disabled. If a board need legacy image format support
3543 enable this through CONFIG_IMAGE_FORMAT_LEGACY
3545 CONFIG_FIT_DISABLE_SHA256
3546 Supporting SHA256 hashes has quite an impact on binary size.
3547 For constrained systems sha256 hash support can be disabled
3550 - Standalone program support:
3551 CONFIG_STANDALONE_LOAD_ADDR
3553 This option defines a board specific value for the
3554 address where standalone program gets loaded, thus
3555 overwriting the architecture dependent default
3558 - Frame Buffer Address:
3561 Define CONFIG_FB_ADDR if you want to use specific
3562 address for frame buffer. This is typically the case
3563 when using a graphics controller has separate video
3564 memory. U-Boot will then place the frame buffer at
3565 the given address instead of dynamically reserving it
3566 in system RAM by calling lcd_setmem(), which grabs
3567 the memory for the frame buffer depending on the
3568 configured panel size.
3570 Please see board_init_f function.
3572 - Automatic software updates via TFTP server
3574 CONFIG_UPDATE_TFTP_CNT_MAX
3575 CONFIG_UPDATE_TFTP_MSEC_MAX
3577 These options enable and control the auto-update feature;
3578 for a more detailed description refer to doc/README.update.
3580 - MTD Support (mtdparts command, UBI support)
3583 Adds the MTD device infrastructure from the Linux kernel.
3584 Needed for mtdparts command support.
3586 CONFIG_MTD_PARTITIONS
3588 Adds the MTD partitioning infrastructure from the Linux
3589 kernel. Needed for UBI support.
3591 CONFIG_MTD_NAND_VERIFY_WRITE
3592 verify if the written data is correct reread.
3597 Adds commands for interacting with MTD partitions formatted
3598 with the UBI flash translation layer
3600 Requires also defining CONFIG_RBTREE
3602 CONFIG_UBI_SILENCE_MSG
3604 Make the verbose messages from UBI stop printing. This leaves
3605 warnings and errors enabled.
3608 CONFIG_MTD_UBI_WL_THRESHOLD
3609 This parameter defines the maximum difference between the highest
3610 erase counter value and the lowest erase counter value of eraseblocks
3611 of UBI devices. When this threshold is exceeded, UBI starts performing
3612 wear leveling by means of moving data from eraseblock with low erase
3613 counter to eraseblocks with high erase counter.
3615 The default value should be OK for SLC NAND flashes, NOR flashes and
3616 other flashes which have eraseblock life-cycle 100000 or more.
3617 However, in case of MLC NAND flashes which typically have eraseblock
3618 life-cycle less than 10000, the threshold should be lessened (e.g.,
3619 to 128 or 256, although it does not have to be power of 2).
3623 CONFIG_MTD_UBI_BEB_LIMIT
3624 This option specifies the maximum bad physical eraseblocks UBI
3625 expects on the MTD device (per 1024 eraseblocks). If the
3626 underlying flash does not admit of bad eraseblocks (e.g. NOR
3627 flash), this value is ignored.
3629 NAND datasheets often specify the minimum and maximum NVM
3630 (Number of Valid Blocks) for the flashes' endurance lifetime.
3631 The maximum expected bad eraseblocks per 1024 eraseblocks
3632 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3633 which gives 20 for most NANDs (MaxNVB is basically the total
3634 count of eraseblocks on the chip).
3636 To put it differently, if this value is 20, UBI will try to
3637 reserve about 1.9% of physical eraseblocks for bad blocks
3638 handling. And that will be 1.9% of eraseblocks on the entire
3639 NAND chip, not just the MTD partition UBI attaches. This means
3640 that if you have, say, a NAND flash chip admits maximum 40 bad
3641 eraseblocks, and it is split on two MTD partitions of the same
3642 size, UBI will reserve 40 eraseblocks when attaching a
3647 CONFIG_MTD_UBI_FASTMAP
3648 Fastmap is a mechanism which allows attaching an UBI device
3649 in nearly constant time. Instead of scanning the whole MTD device it
3650 only has to locate a checkpoint (called fastmap) on the device.
3651 The on-flash fastmap contains all information needed to attach
3652 the device. Using fastmap makes only sense on large devices where
3653 attaching by scanning takes long. UBI will not automatically install
3654 a fastmap on old images, but you can set the UBI parameter
3655 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3656 that fastmap-enabled images are still usable with UBI implementations
3657 without fastmap support. On typical flash devices the whole fastmap
3658 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3660 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3661 Set this parameter to enable fastmap automatically on images
3668 Adds commands for interacting with UBI volumes formatted as
3669 UBIFS. UBIFS is read-only in u-boot.
3671 Requires UBI support as well as CONFIG_LZO
3673 CONFIG_UBIFS_SILENCE_MSG
3675 Make the verbose messages from UBIFS stop printing. This leaves
3676 warnings and errors enabled.
3680 Enable building of SPL globally.
3683 LDSCRIPT for linking the SPL binary.
3685 CONFIG_SPL_MAX_FOOTPRINT
3686 Maximum size in memory allocated to the SPL, BSS included.
3687 When defined, the linker checks that the actual memory
3688 used by SPL from _start to __bss_end does not exceed it.
3689 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3690 must not be both defined at the same time.
3693 Maximum size of the SPL image (text, data, rodata, and
3694 linker lists sections), BSS excluded.
3695 When defined, the linker checks that the actual size does
3698 CONFIG_SPL_TEXT_BASE
3699 TEXT_BASE for linking the SPL binary.
3701 CONFIG_SPL_RELOC_TEXT_BASE
3702 Address to relocate to. If unspecified, this is equal to
3703 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3705 CONFIG_SPL_BSS_START_ADDR
3706 Link address for the BSS within the SPL binary.
3708 CONFIG_SPL_BSS_MAX_SIZE
3709 Maximum size in memory allocated to the SPL BSS.
3710 When defined, the linker checks that the actual memory used
3711 by SPL from __bss_start to __bss_end does not exceed it.
3712 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3713 must not be both defined at the same time.
3716 Adress of the start of the stack SPL will use
3718 CONFIG_SPL_RELOC_STACK
3719 Adress of the start of the stack SPL will use after
3720 relocation. If unspecified, this is equal to
3723 CONFIG_SYS_SPL_MALLOC_START
3724 Starting address of the malloc pool used in SPL.
3726 CONFIG_SYS_SPL_MALLOC_SIZE
3727 The size of the malloc pool used in SPL.
3729 CONFIG_SPL_FRAMEWORK
3730 Enable the SPL framework under common/. This framework
3731 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3732 NAND loading of the Linux Kernel.
3735 Enable booting directly to an OS from SPL.
3736 See also: doc/README.falcon
3738 CONFIG_SPL_DISPLAY_PRINT
3739 For ARM, enable an optional function to print more information
3740 about the running system.
3742 CONFIG_SPL_INIT_MINIMAL
3743 Arch init code should be built for a very small image
3745 CONFIG_SPL_LIBCOMMON_SUPPORT
3746 Support for common/libcommon.o in SPL binary
3748 CONFIG_SPL_LIBDISK_SUPPORT
3749 Support for disk/libdisk.o in SPL binary
3751 CONFIG_SPL_I2C_SUPPORT
3752 Support for drivers/i2c/libi2c.o in SPL binary
3754 CONFIG_SPL_GPIO_SUPPORT
3755 Support for drivers/gpio/libgpio.o in SPL binary
3757 CONFIG_SPL_MMC_SUPPORT
3758 Support for drivers/mmc/libmmc.o in SPL binary
3760 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3761 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3762 Address and partition on the MMC to load U-Boot from
3763 when the MMC is being used in raw mode.
3765 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3766 Partition on the MMC to load U-Boot from when the MMC is being
3769 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3770 Sector to load kernel uImage from when MMC is being
3771 used in raw mode (for Falcon mode)
3773 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3774 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3775 Sector and number of sectors to load kernel argument
3776 parameters from when MMC is being used in raw mode
3779 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3780 Partition on the MMC to load U-Boot from when the MMC is being
3783 CONFIG_SPL_FAT_SUPPORT
3784 Support for fs/fat/libfat.o in SPL binary
3786 CONFIG_SPL_EXT_SUPPORT
3787 Support for EXT filesystem in SPL binary
3789 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3790 Filename to read to load U-Boot when reading from filesystem
3792 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3793 Filename to read to load kernel uImage when reading
3794 from filesystem (for Falcon mode)
3796 CONFIG_SPL_FS_LOAD_ARGS_NAME
3797 Filename to read to load kernel argument parameters
3798 when reading from filesystem (for Falcon mode)
3800 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3801 Set this for NAND SPL on PPC mpc83xx targets, so that
3802 start.S waits for the rest of the SPL to load before
3803 continuing (the hardware starts execution after just
3804 loading the first page rather than the full 4K).
3806 CONFIG_SPL_SKIP_RELOCATE
3807 Avoid SPL relocation
3809 CONFIG_SPL_NAND_BASE
3810 Include nand_base.c in the SPL. Requires
3811 CONFIG_SPL_NAND_DRIVERS.
3813 CONFIG_SPL_NAND_DRIVERS
3814 SPL uses normal NAND drivers, not minimal drivers.
3817 Include standard software ECC in the SPL
3819 CONFIG_SPL_NAND_SIMPLE
3820 Support for NAND boot using simple NAND drivers that
3821 expose the cmd_ctrl() interface.
3823 CONFIG_SPL_MTD_SUPPORT
3824 Support for the MTD subsystem within SPL. Useful for
3825 environment on NAND support within SPL.
3827 CONFIG_SPL_NAND_RAW_ONLY
3828 Support to boot only raw u-boot.bin images. Use this only
3829 if you need to save space.
3831 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3832 Set for the SPL on PPC mpc8xxx targets, support for
3833 drivers/ddr/fsl/libddr.o in SPL binary.
3835 CONFIG_SPL_COMMON_INIT_DDR
3836 Set for common ddr init with serial presence detect in
3839 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3840 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3841 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3842 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3843 CONFIG_SYS_NAND_ECCBYTES
3844 Defines the size and behavior of the NAND that SPL uses
3847 CONFIG_SPL_NAND_BOOT
3848 Add support NAND boot
3850 CONFIG_SYS_NAND_U_BOOT_OFFS
3851 Location in NAND to read U-Boot from
3853 CONFIG_SYS_NAND_U_BOOT_DST
3854 Location in memory to load U-Boot to
3856 CONFIG_SYS_NAND_U_BOOT_SIZE
3857 Size of image to load
3859 CONFIG_SYS_NAND_U_BOOT_START
3860 Entry point in loaded image to jump to
3862 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3863 Define this if you need to first read the OOB and then the
3864 data. This is used, for example, on davinci platforms.
3866 CONFIG_SPL_OMAP3_ID_NAND
3867 Support for an OMAP3-specific set of functions to return the
3868 ID and MFR of the first attached NAND chip, if present.
3870 CONFIG_SPL_SERIAL_SUPPORT
3871 Support for drivers/serial/libserial.o in SPL binary
3873 CONFIG_SPL_SPI_FLASH_SUPPORT
3874 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3876 CONFIG_SPL_SPI_SUPPORT
3877 Support for drivers/spi/libspi.o in SPL binary
3879 CONFIG_SPL_RAM_DEVICE
3880 Support for running image already present in ram, in SPL binary
3882 CONFIG_SPL_LIBGENERIC_SUPPORT
3883 Support for lib/libgeneric.o in SPL binary
3885 CONFIG_SPL_ENV_SUPPORT
3886 Support for the environment operating in SPL binary
3888 CONFIG_SPL_NET_SUPPORT
3889 Support for the net/libnet.o in SPL binary.
3890 It conflicts with SPL env from storage medium specified by
3891 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3894 Image offset to which the SPL should be padded before appending
3895 the SPL payload. By default, this is defined as
3896 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3897 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3898 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3901 Final target image containing SPL and payload. Some SPLs
3902 use an arch-specific makefile fragment instead, for
3903 example if more than one image needs to be produced.
3905 CONFIG_FIT_SPL_PRINT
3906 Printing information about a FIT image adds quite a bit of
3907 code to SPL. So this is normally disabled in SPL. Use this
3908 option to re-enable it. This will affect the output of the
3909 bootm command when booting a FIT image.
3913 Enable building of TPL globally.
3916 Image offset to which the TPL should be padded before appending
3917 the TPL payload. By default, this is defined as
3918 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3919 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3920 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3925 [so far only for SMDK2400 boards]
3927 - Modem support enable:
3928 CONFIG_MODEM_SUPPORT
3930 - RTS/CTS Flow control enable:
3933 - Modem debug support:
3934 CONFIG_MODEM_SUPPORT_DEBUG
3936 Enables debugging stuff (char screen[1024], dbg())
3937 for modem support. Useful only with BDI2000.
3939 - Interrupt support (PPC):
3941 There are common interrupt_init() and timer_interrupt()
3942 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3943 for CPU specific initialization. interrupt_init_cpu()
3944 should set decrementer_count to appropriate value. If
3945 CPU resets decrementer automatically after interrupt
3946 (ppc4xx) it should set decrementer_count to zero.
3947 timer_interrupt() calls timer_interrupt_cpu() for CPU
3948 specific handling. If board has watchdog / status_led
3949 / other_activity_monitor it works automatically from
3950 general timer_interrupt().
3954 In the target system modem support is enabled when a
3955 specific key (key combination) is pressed during
3956 power-on. Otherwise U-Boot will boot normally
3957 (autoboot). The key_pressed() function is called from
3958 board_init(). Currently key_pressed() is a dummy
3959 function, returning 1 and thus enabling modem
3962 If there are no modem init strings in the
3963 environment, U-Boot proceed to autoboot; the
3964 previous output (banner, info printfs) will be
3967 See also: doc/README.Modem
3969 Board initialization settings:
3970 ------------------------------
3972 During Initialization u-boot calls a number of board specific functions
3973 to allow the preparation of board specific prerequisites, e.g. pin setup
3974 before drivers are initialized. To enable these callbacks the
3975 following configuration macros have to be defined. Currently this is
3976 architecture specific, so please check arch/your_architecture/lib/board.c
3977 typically in board_init_f() and board_init_r().
3979 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3980 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3981 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3982 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3984 Configuration Settings:
3985 -----------------------
3987 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3988 Optionally it can be defined to support 64-bit memory commands.
3990 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3991 undefine this when you're short of memory.
3993 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3994 width of the commands listed in the 'help' command output.
3996 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3997 prompt for user input.
3999 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
4001 - CONFIG_SYS_PBSIZE: Buffer size for Console output
4003 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
4005 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
4006 the application (usually a Linux kernel) when it is
4009 - CONFIG_SYS_BAUDRATE_TABLE:
4010 List of legal baudrate settings for this board.
4012 - CONFIG_SYS_CONSOLE_INFO_QUIET
4013 Suppress display of console information at boot.
4015 - CONFIG_SYS_CONSOLE_IS_IN_ENV
4016 If the board specific function
4017 extern int overwrite_console (void);
4018 returns 1, the stdin, stderr and stdout are switched to the
4019 serial port, else the settings in the environment are used.
4021 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
4022 Enable the call to overwrite_console().
4024 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
4025 Enable overwrite of previous console environment settings.
4027 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
4028 Begin and End addresses of the area used by the
4031 - CONFIG_SYS_ALT_MEMTEST:
4032 Enable an alternate, more extensive memory test.
4034 - CONFIG_SYS_MEMTEST_SCRATCH:
4035 Scratch address used by the alternate memory test
4036 You only need to set this if address zero isn't writeable
4038 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
4039 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
4040 this specified memory area will get subtracted from the top
4041 (end) of RAM and won't get "touched" at all by U-Boot. By
4042 fixing up gd->ram_size the Linux kernel should gets passed
4043 the now "corrected" memory size and won't touch it either.
4044 This should work for arch/ppc and arch/powerpc. Only Linux
4045 board ports in arch/powerpc with bootwrapper support that
4046 recalculate the memory size from the SDRAM controller setup
4047 will have to get fixed in Linux additionally.
4049 This option can be used as a workaround for the 440EPx/GRx
4050 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
4053 WARNING: Please make sure that this value is a multiple of
4054 the Linux page size (normally 4k). If this is not the case,
4055 then the end address of the Linux memory will be located at a
4056 non page size aligned address and this could cause major
4059 - CONFIG_SYS_LOADS_BAUD_CHANGE:
4060 Enable temporary baudrate change while serial download
4062 - CONFIG_SYS_SDRAM_BASE:
4063 Physical start address of SDRAM. _Must_ be 0 here.
4065 - CONFIG_SYS_MBIO_BASE:
4066 Physical start address of Motherboard I/O (if using a
4069 - CONFIG_SYS_FLASH_BASE:
4070 Physical start address of Flash memory.
4072 - CONFIG_SYS_MONITOR_BASE:
4073 Physical start address of boot monitor code (set by
4074 make config files to be same as the text base address
4075 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
4076 CONFIG_SYS_FLASH_BASE when booting from flash.
4078 - CONFIG_SYS_MONITOR_LEN:
4079 Size of memory reserved for monitor code, used to
4080 determine _at_compile_time_ (!) if the environment is
4081 embedded within the U-Boot image, or in a separate
4084 - CONFIG_SYS_MALLOC_LEN:
4085 Size of DRAM reserved for malloc() use.
4087 - CONFIG_SYS_MALLOC_F_LEN
4088 Size of the malloc() pool for use before relocation. If
4089 this is defined, then a very simple malloc() implementation
4090 will become available before relocation. The address is just
4091 below the global data, and the stack is moved down to make
4094 This feature allocates regions with increasing addresses
4095 within the region. calloc() is supported, but realloc()
4096 is not available. free() is supported but does nothing.
4097 The memory will be freed (or in fact just forgotten) when
4098 U-Boot relocates itself.
4100 Pre-relocation malloc() is only supported on ARM and sandbox
4101 at present but is fairly easy to enable for other archs.
4103 - CONFIG_SYS_MALLOC_SIMPLE
4104 Provides a simple and small malloc() and calloc() for those
4105 boards which do not use the full malloc in SPL (which is
4106 enabled with CONFIG_SYS_SPL_MALLOC_START).
4108 - CONFIG_SYS_NONCACHED_MEMORY:
4109 Size of non-cached memory area. This area of memory will be
4110 typically located right below the malloc() area and mapped
4111 uncached in the MMU. This is useful for drivers that would
4112 otherwise require a lot of explicit cache maintenance. For
4113 some drivers it's also impossible to properly maintain the
4114 cache. For example if the regions that need to be flushed
4115 are not a multiple of the cache-line size, *and* padding
4116 cannot be allocated between the regions to align them (i.e.
4117 if the HW requires a contiguous array of regions, and the
4118 size of each region is not cache-aligned), then a flush of
4119 one region may result in overwriting data that hardware has
4120 written to another region in the same cache-line. This can
4121 happen for example in network drivers where descriptors for
4122 buffers are typically smaller than the CPU cache-line (e.g.
4123 16 bytes vs. 32 or 64 bytes).
4125 Non-cached memory is only supported on 32-bit ARM at present.
4127 - CONFIG_SYS_BOOTM_LEN:
4128 Normally compressed uImages are limited to an
4129 uncompressed size of 8 MBytes. If this is not enough,
4130 you can define CONFIG_SYS_BOOTM_LEN in your board config file
4131 to adjust this setting to your needs.
4133 - CONFIG_SYS_BOOTMAPSZ:
4134 Maximum size of memory mapped by the startup code of
4135 the Linux kernel; all data that must be processed by
4136 the Linux kernel (bd_info, boot arguments, FDT blob if
4137 used) must be put below this limit, unless "bootm_low"
4138 environment variable is defined and non-zero. In such case
4139 all data for the Linux kernel must be between "bootm_low"
4140 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
4141 variable "bootm_mapsize" will override the value of
4142 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
4143 then the value in "bootm_size" will be used instead.
4145 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
4146 Enable initrd_high functionality. If defined then the
4147 initrd_high feature is enabled and the bootm ramdisk subcommand
4150 - CONFIG_SYS_BOOT_GET_CMDLINE:
4151 Enables allocating and saving kernel cmdline in space between
4152 "bootm_low" and "bootm_low" + BOOTMAPSZ.
4154 - CONFIG_SYS_BOOT_GET_KBD:
4155 Enables allocating and saving a kernel copy of the bd_info in
4156 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
4158 - CONFIG_SYS_MAX_FLASH_BANKS:
4159 Max number of Flash memory banks
4161 - CONFIG_SYS_MAX_FLASH_SECT:
4162 Max number of sectors on a Flash chip
4164 - CONFIG_SYS_FLASH_ERASE_TOUT:
4165 Timeout for Flash erase operations (in ms)
4167 - CONFIG_SYS_FLASH_WRITE_TOUT:
4168 Timeout for Flash write operations (in ms)
4170 - CONFIG_SYS_FLASH_LOCK_TOUT
4171 Timeout for Flash set sector lock bit operation (in ms)
4173 - CONFIG_SYS_FLASH_UNLOCK_TOUT
4174 Timeout for Flash clear lock bits operation (in ms)
4176 - CONFIG_SYS_FLASH_PROTECTION
4177 If defined, hardware flash sectors protection is used
4178 instead of U-Boot software protection.
4180 - CONFIG_SYS_DIRECT_FLASH_TFTP:
4182 Enable TFTP transfers directly to flash memory;
4183 without this option such a download has to be
4184 performed in two steps: (1) download to RAM, and (2)
4185 copy from RAM to flash.
4187 The two-step approach is usually more reliable, since
4188 you can check if the download worked before you erase
4189 the flash, but in some situations (when system RAM is
4190 too limited to allow for a temporary copy of the
4191 downloaded image) this option may be very useful.
4193 - CONFIG_SYS_FLASH_CFI:
4194 Define if the flash driver uses extra elements in the
4195 common flash structure for storing flash geometry.
4197 - CONFIG_FLASH_CFI_DRIVER
4198 This option also enables the building of the cfi_flash driver
4199 in the drivers directory
4201 - CONFIG_FLASH_CFI_MTD
4202 This option enables the building of the cfi_mtd driver
4203 in the drivers directory. The driver exports CFI flash
4206 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
4207 Use buffered writes to flash.
4209 - CONFIG_FLASH_SPANSION_S29WS_N
4210 s29ws-n MirrorBit flash has non-standard addresses for buffered
4213 - CONFIG_SYS_FLASH_QUIET_TEST
4214 If this option is defined, the common CFI flash doesn't
4215 print it's warning upon not recognized FLASH banks. This
4216 is useful, if some of the configured banks are only
4217 optionally available.
4219 - CONFIG_FLASH_SHOW_PROGRESS
4220 If defined (must be an integer), print out countdown
4221 digits and dots. Recommended value: 45 (9..1) for 80
4222 column displays, 15 (3..1) for 40 column displays.
4224 - CONFIG_FLASH_VERIFY
4225 If defined, the content of the flash (destination) is compared
4226 against the source after the write operation. An error message
4227 will be printed when the contents are not identical.
4228 Please note that this option is useless in nearly all cases,
4229 since such flash programming errors usually are detected earlier
4230 while unprotecting/erasing/programming. Please only enable
4231 this option if you really know what you are doing.
4233 - CONFIG_SYS_RX_ETH_BUFFER:
4234 Defines the number of Ethernet receive buffers. On some
4235 Ethernet controllers it is recommended to set this value
4236 to 8 or even higher (EEPRO100 or 405 EMAC), since all
4237 buffers can be full shortly after enabling the interface
4238 on high Ethernet traffic.
4239 Defaults to 4 if not defined.
4241 - CONFIG_ENV_MAX_ENTRIES
4243 Maximum number of entries in the hash table that is used
4244 internally to store the environment settings. The default
4245 setting is supposed to be generous and should work in most
4246 cases. This setting can be used to tune behaviour; see
4247 lib/hashtable.c for details.
4249 - CONFIG_ENV_FLAGS_LIST_DEFAULT
4250 - CONFIG_ENV_FLAGS_LIST_STATIC
4251 Enable validation of the values given to environment variables when
4252 calling env set. Variables can be restricted to only decimal,
4253 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
4254 the variables can also be restricted to IP address or MAC address.
4256 The format of the list is:
4257 type_attribute = [s|d|x|b|i|m]
4258 access_attribute = [a|r|o|c]
4259 attributes = type_attribute[access_attribute]
4260 entry = variable_name[:attributes]
4263 The type attributes are:
4264 s - String (default)
4267 b - Boolean ([1yYtT|0nNfF])
4271 The access attributes are:
4277 - CONFIG_ENV_FLAGS_LIST_DEFAULT
4278 Define this to a list (string) to define the ".flags"
4279 environment variable in the default or embedded environment.
4281 - CONFIG_ENV_FLAGS_LIST_STATIC
4282 Define this to a list (string) to define validation that
4283 should be done if an entry is not found in the ".flags"
4284 environment variable. To override a setting in the static
4285 list, simply add an entry for the same variable name to the
4288 - CONFIG_ENV_ACCESS_IGNORE_FORCE
4289 If defined, don't allow the -f switch to env set override variable
4292 - CONFIG_SYS_GENERIC_BOARD
4293 This selects the architecture-generic board system instead of the
4294 architecture-specific board files. It is intended to move boards
4295 to this new framework over time. Defining this will disable the
4296 arch/foo/lib/board.c file and use common/board_f.c and
4297 common/board_r.c instead. To use this option your architecture
4298 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
4299 its config.mk file). If you find problems enabling this option on
4300 your board please report the problem and send patches!
4302 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
4303 This is set by OMAP boards for the max time that reset should
4304 be asserted. See doc/README.omap-reset-time for details on how
4305 the value can be calculated on a given board.
4308 If stdint.h is available with your toolchain you can define this
4309 option to enable it. You can provide option 'USE_STDINT=1' when
4310 building U-Boot to enable this.
4312 The following definitions that deal with the placement and management
4313 of environment data (variable area); in general, we support the
4314 following configurations:
4316 - CONFIG_BUILD_ENVCRC:
4318 Builds up envcrc with the target environment so that external utils
4319 may easily extract it and embed it in final U-Boot images.
4321 - CONFIG_ENV_IS_IN_FLASH:
4323 Define this if the environment is in flash memory.
4325 a) The environment occupies one whole flash sector, which is
4326 "embedded" in the text segment with the U-Boot code. This
4327 happens usually with "bottom boot sector" or "top boot
4328 sector" type flash chips, which have several smaller
4329 sectors at the start or the end. For instance, such a
4330 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
4331 such a case you would place the environment in one of the
4332 4 kB sectors - with U-Boot code before and after it. With
4333 "top boot sector" type flash chips, you would put the
4334 environment in one of the last sectors, leaving a gap
4335 between U-Boot and the environment.
4337 - CONFIG_ENV_OFFSET:
4339 Offset of environment data (variable area) to the
4340 beginning of flash memory; for instance, with bottom boot
4341 type flash chips the second sector can be used: the offset
4342 for this sector is given here.
4344 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
4348 This is just another way to specify the start address of
4349 the flash sector containing the environment (instead of
4352 - CONFIG_ENV_SECT_SIZE:
4354 Size of the sector containing the environment.
4357 b) Sometimes flash chips have few, equal sized, BIG sectors.
4358 In such a case you don't want to spend a whole sector for
4363 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
4364 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
4365 of this flash sector for the environment. This saves
4366 memory for the RAM copy of the environment.
4368 It may also save flash memory if you decide to use this
4369 when your environment is "embedded" within U-Boot code,
4370 since then the remainder of the flash sector could be used
4371 for U-Boot code. It should be pointed out that this is
4372 STRONGLY DISCOURAGED from a robustness point of view:
4373 updating the environment in flash makes it always
4374 necessary to erase the WHOLE sector. If something goes
4375 wrong before the contents has been restored from a copy in
4376 RAM, your target system will be dead.
4378 - CONFIG_ENV_ADDR_REDUND
4379 CONFIG_ENV_SIZE_REDUND
4381 These settings describe a second storage area used to hold
4382 a redundant copy of the environment data, so that there is
4383 a valid backup copy in case there is a power failure during
4384 a "saveenv" operation.
4386 BE CAREFUL! Any changes to the flash layout, and some changes to the
4387 source code will make it necessary to adapt <board>/u-boot.lds*
4391 - CONFIG_ENV_IS_IN_NVRAM:
4393 Define this if you have some non-volatile memory device
4394 (NVRAM, battery buffered SRAM) which you want to use for the
4400 These two #defines are used to determine the memory area you
4401 want to use for environment. It is assumed that this memory
4402 can just be read and written to, without any special
4405 BE CAREFUL! The first access to the environment happens quite early
4406 in U-Boot initialization (when we try to get the setting of for the
4407 console baudrate). You *MUST* have mapped your NVRAM area then, or
4410 Please note that even with NVRAM we still use a copy of the
4411 environment in RAM: we could work on NVRAM directly, but we want to
4412 keep settings there always unmodified except somebody uses "saveenv"
4413 to save the current settings.
4416 - CONFIG_ENV_IS_IN_EEPROM:
4418 Use this if you have an EEPROM or similar serial access
4419 device and a driver for it.
4421 - CONFIG_ENV_OFFSET:
4424 These two #defines specify the offset and size of the
4425 environment area within the total memory of your EEPROM.
4427 - CONFIG_SYS_I2C_EEPROM_ADDR:
4428 If defined, specified the chip address of the EEPROM device.
4429 The default address is zero.
4431 - CONFIG_SYS_I2C_EEPROM_BUS:
4432 If defined, specified the i2c bus of the EEPROM device.
4434 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
4435 If defined, the number of bits used to address bytes in a
4436 single page in the EEPROM device. A 64 byte page, for example
4437 would require six bits.
4439 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
4440 If defined, the number of milliseconds to delay between
4441 page writes. The default is zero milliseconds.
4443 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
4444 The length in bytes of the EEPROM memory array address. Note
4445 that this is NOT the chip address length!
4447 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
4448 EEPROM chips that implement "address overflow" are ones
4449 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
4450 address and the extra bits end up in the "chip address" bit
4451 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
4454 Note that we consider the length of the address field to
4455 still be one byte because the extra address bits are hidden
4456 in the chip address.
4458 - CONFIG_SYS_EEPROM_SIZE:
4459 The size in bytes of the EEPROM device.
4461 - CONFIG_ENV_EEPROM_IS_ON_I2C
4462 define this, if you have I2C and SPI activated, and your
4463 EEPROM, which holds the environment, is on the I2C bus.
4465 - CONFIG_I2C_ENV_EEPROM_BUS
4466 if you have an Environment on an EEPROM reached over
4467 I2C muxes, you can define here, how to reach this
4468 EEPROM. For example:
4470 #define CONFIG_I2C_ENV_EEPROM_BUS 1
4472 EEPROM which holds the environment, is reached over
4473 a pca9547 i2c mux with address 0x70, channel 3.
4475 - CONFIG_ENV_IS_IN_DATAFLASH:
4477 Define this if you have a DataFlash memory device which you
4478 want to use for the environment.
4480 - CONFIG_ENV_OFFSET:
4484 These three #defines specify the offset and size of the
4485 environment area within the total memory of your DataFlash placed
4486 at the specified address.
4488 - CONFIG_ENV_IS_IN_SPI_FLASH:
4490 Define this if you have a SPI Flash memory device which you
4491 want to use for the environment.
4493 - CONFIG_ENV_OFFSET:
4496 These two #defines specify the offset and size of the
4497 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
4498 aligned to an erase sector boundary.
4500 - CONFIG_ENV_SECT_SIZE:
4502 Define the SPI flash's sector size.
4504 - CONFIG_ENV_OFFSET_REDUND (optional):
4506 This setting describes a second storage area of CONFIG_ENV_SIZE
4507 size used to hold a redundant copy of the environment data, so
4508 that there is a valid backup copy in case there is a power failure
4509 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4510 aligned to an erase sector boundary.
4512 - CONFIG_ENV_SPI_BUS (optional):
4513 - CONFIG_ENV_SPI_CS (optional):
4515 Define the SPI bus and chip select. If not defined they will be 0.
4517 - CONFIG_ENV_SPI_MAX_HZ (optional):
4519 Define the SPI max work clock. If not defined then use 1MHz.
4521 - CONFIG_ENV_SPI_MODE (optional):
4523 Define the SPI work mode. If not defined then use SPI_MODE_3.
4525 - CONFIG_ENV_IS_IN_REMOTE:
4527 Define this if you have a remote memory space which you
4528 want to use for the local device's environment.
4533 These two #defines specify the address and size of the
4534 environment area within the remote memory space. The
4535 local device can get the environment from remote memory
4536 space by SRIO or PCIE links.
4538 BE CAREFUL! For some special cases, the local device can not use
4539 "saveenv" command. For example, the local device will get the
4540 environment stored in a remote NOR flash by SRIO or PCIE link,
4541 but it can not erase, write this NOR flash by SRIO or PCIE interface.
4543 - CONFIG_ENV_IS_IN_NAND:
4545 Define this if you have a NAND device which you want to use
4546 for the environment.
4548 - CONFIG_ENV_OFFSET:
4551 These two #defines specify the offset and size of the environment
4552 area within the first NAND device. CONFIG_ENV_OFFSET must be
4553 aligned to an erase block boundary.
4555 - CONFIG_ENV_OFFSET_REDUND (optional):
4557 This setting describes a second storage area of CONFIG_ENV_SIZE
4558 size used to hold a redundant copy of the environment data, so
4559 that there is a valid backup copy in case there is a power failure
4560 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4561 aligned to an erase block boundary.
4563 - CONFIG_ENV_RANGE (optional):
4565 Specifies the length of the region in which the environment
4566 can be written. This should be a multiple of the NAND device's
4567 block size. Specifying a range with more erase blocks than
4568 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4569 the range to be avoided.
4571 - CONFIG_ENV_OFFSET_OOB (optional):
4573 Enables support for dynamically retrieving the offset of the
4574 environment from block zero's out-of-band data. The
4575 "nand env.oob" command can be used to record this offset.
4576 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4577 using CONFIG_ENV_OFFSET_OOB.
4579 - CONFIG_NAND_ENV_DST
4581 Defines address in RAM to which the nand_spl code should copy the
4582 environment. If redundant environment is used, it will be copied to
4583 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4585 - CONFIG_ENV_IS_IN_UBI:
4587 Define this if you have an UBI volume that you want to use for the
4588 environment. This has the benefit of wear-leveling the environment
4589 accesses, which is important on NAND.
4591 - CONFIG_ENV_UBI_PART:
4593 Define this to a string that is the mtd partition containing the UBI.
4595 - CONFIG_ENV_UBI_VOLUME:
4597 Define this to the name of the volume that you want to store the
4600 - CONFIG_ENV_UBI_VOLUME_REDUND:
4602 Define this to the name of another volume to store a second copy of
4603 the environment in. This will enable redundant environments in UBI.
4604 It is assumed that both volumes are in the same MTD partition.
4606 - CONFIG_UBI_SILENCE_MSG
4607 - CONFIG_UBIFS_SILENCE_MSG
4609 You will probably want to define these to avoid a really noisy system
4610 when storing the env in UBI.
4612 - CONFIG_ENV_IS_IN_FAT:
4613 Define this if you want to use the FAT file system for the environment.
4615 - FAT_ENV_INTERFACE:
4617 Define this to a string that is the name of the block device.
4619 - FAT_ENV_DEV_AND_PART:
4621 Define this to a string to specify the partition of the device. It can
4624 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4625 - "D:P": device D partition P. Error occurs if device D has no
4628 - "D" or "D:": device D partition 1 if device D has partition
4629 table, or the whole device D if has no partition
4631 - "D:auto": first partition in device D with bootable flag set.
4632 If none, first valid partition in device D. If no
4633 partition table then means device D.
4637 It's a string of the FAT file name. This file use to store the
4641 This should be defined. Otherwise it cannot save the environment file.
4643 - CONFIG_ENV_IS_IN_MMC:
4645 Define this if you have an MMC device which you want to use for the
4648 - CONFIG_SYS_MMC_ENV_DEV:
4650 Specifies which MMC device the environment is stored in.
4652 - CONFIG_SYS_MMC_ENV_PART (optional):
4654 Specifies which MMC partition the environment is stored in. If not
4655 set, defaults to partition 0, the user area. Common values might be
4656 1 (first MMC boot partition), 2 (second MMC boot partition).
4658 - CONFIG_ENV_OFFSET:
4661 These two #defines specify the offset and size of the environment
4662 area within the specified MMC device.
4664 If offset is positive (the usual case), it is treated as relative to
4665 the start of the MMC partition. If offset is negative, it is treated
4666 as relative to the end of the MMC partition. This can be useful if
4667 your board may be fitted with different MMC devices, which have
4668 different sizes for the MMC partitions, and you always want the
4669 environment placed at the very end of the partition, to leave the
4670 maximum possible space before it, to store other data.
4672 These two values are in units of bytes, but must be aligned to an
4673 MMC sector boundary.
4675 - CONFIG_ENV_OFFSET_REDUND (optional):
4677 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4678 hold a redundant copy of the environment data. This provides a
4679 valid backup copy in case the other copy is corrupted, e.g. due
4680 to a power failure during a "saveenv" operation.
4682 This value may also be positive or negative; this is handled in the
4683 same way as CONFIG_ENV_OFFSET.
4685 This value is also in units of bytes, but must also be aligned to
4686 an MMC sector boundary.
4688 - CONFIG_ENV_SIZE_REDUND (optional):
4690 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4691 set. If this value is set, it must be set to the same value as
4694 - CONFIG_SYS_SPI_INIT_OFFSET
4696 Defines offset to the initial SPI buffer area in DPRAM. The
4697 area is used at an early stage (ROM part) if the environment
4698 is configured to reside in the SPI EEPROM: We need a 520 byte
4699 scratch DPRAM area. It is used between the two initialization
4700 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4701 to be a good choice since it makes it far enough from the
4702 start of the data area as well as from the stack pointer.
4704 Please note that the environment is read-only until the monitor
4705 has been relocated to RAM and a RAM copy of the environment has been
4706 created; also, when using EEPROM you will have to use getenv_f()
4707 until then to read environment variables.
4709 The environment is protected by a CRC32 checksum. Before the monitor
4710 is relocated into RAM, as a result of a bad CRC you will be working
4711 with the compiled-in default environment - *silently*!!! [This is
4712 necessary, because the first environment variable we need is the
4713 "baudrate" setting for the console - if we have a bad CRC, we don't
4714 have any device yet where we could complain.]
4716 Note: once the monitor has been relocated, then it will complain if
4717 the default environment is used; a new CRC is computed as soon as you
4718 use the "saveenv" command to store a valid environment.
4720 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4721 Echo the inverted Ethernet link state to the fault LED.
4723 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4724 also needs to be defined.
4726 - CONFIG_SYS_FAULT_MII_ADDR:
4727 MII address of the PHY to check for the Ethernet link state.
4729 - CONFIG_NS16550_MIN_FUNCTIONS:
4730 Define this if you desire to only have use of the NS16550_init
4731 and NS16550_putc functions for the serial driver located at
4732 drivers/serial/ns16550.c. This option is useful for saving
4733 space for already greatly restricted images, including but not
4734 limited to NAND_SPL configurations.
4736 - CONFIG_DISPLAY_BOARDINFO
4737 Display information about the board that U-Boot is running on
4738 when U-Boot starts up. The board function checkboard() is called
4741 - CONFIG_DISPLAY_BOARDINFO_LATE
4742 Similar to the previous option, but display this information
4743 later, once stdio is running and output goes to the LCD, if
4746 - CONFIG_BOARD_SIZE_LIMIT:
4747 Maximum size of the U-Boot image. When defined, the
4748 build system checks that the actual size does not
4751 Low Level (hardware related) configuration options:
4752 ---------------------------------------------------
4754 - CONFIG_SYS_CACHELINE_SIZE:
4755 Cache Line Size of the CPU.
4757 - CONFIG_SYS_DEFAULT_IMMR:
4758 Default address of the IMMR after system reset.
4760 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4761 and RPXsuper) to be able to adjust the position of
4762 the IMMR register after a reset.
4764 - CONFIG_SYS_CCSRBAR_DEFAULT:
4765 Default (power-on reset) physical address of CCSR on Freescale
4768 - CONFIG_SYS_CCSRBAR:
4769 Virtual address of CCSR. On a 32-bit build, this is typically
4770 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4772 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4773 for cross-platform code that uses that macro instead.
4775 - CONFIG_SYS_CCSRBAR_PHYS:
4776 Physical address of CCSR. CCSR can be relocated to a new
4777 physical address, if desired. In this case, this macro should
4778 be set to that address. Otherwise, it should be set to the
4779 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4780 is typically relocated on 36-bit builds. It is recommended
4781 that this macro be defined via the _HIGH and _LOW macros:
4783 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4784 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4786 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4787 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4788 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4789 used in assembly code, so it must not contain typecasts or
4790 integer size suffixes (e.g. "ULL").
4792 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4793 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4794 used in assembly code, so it must not contain typecasts or
4795 integer size suffixes (e.g. "ULL").
4797 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4798 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4799 forced to a value that ensures that CCSR is not relocated.
4801 - Floppy Disk Support:
4802 CONFIG_SYS_FDC_DRIVE_NUMBER
4804 the default drive number (default value 0)
4806 CONFIG_SYS_ISA_IO_STRIDE
4808 defines the spacing between FDC chipset registers
4811 CONFIG_SYS_ISA_IO_OFFSET
4813 defines the offset of register from address. It
4814 depends on which part of the data bus is connected to
4815 the FDC chipset. (default value 0)
4817 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4818 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4821 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4822 fdc_hw_init() is called at the beginning of the FDC
4823 setup. fdc_hw_init() must be provided by the board
4824 source code. It is used to make hardware-dependent
4828 Most IDE controllers were designed to be connected with PCI
4829 interface. Only few of them were designed for AHB interface.
4830 When software is doing ATA command and data transfer to
4831 IDE devices through IDE-AHB controller, some additional
4832 registers accessing to these kind of IDE-AHB controller
4835 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4836 DO NOT CHANGE unless you know exactly what you're
4837 doing! (11-4) [MPC8xx/82xx systems only]
4839 - CONFIG_SYS_INIT_RAM_ADDR:
4841 Start address of memory area that can be used for
4842 initial data and stack; please note that this must be
4843 writable memory that is working WITHOUT special
4844 initialization, i. e. you CANNOT use normal RAM which
4845 will become available only after programming the
4846 memory controller and running certain initialization
4849 U-Boot uses the following memory types:
4850 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4851 - MPC824X: data cache
4852 - PPC4xx: data cache
4854 - CONFIG_SYS_GBL_DATA_OFFSET:
4856 Offset of the initial data structure in the memory
4857 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4858 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4859 data is located at the end of the available space
4860 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4861 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4862 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4863 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4866 On the MPC824X (or other systems that use the data
4867 cache for initial memory) the address chosen for
4868 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4869 point to an otherwise UNUSED address space between
4870 the top of RAM and the start of the PCI space.
4872 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4874 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4876 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4878 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4880 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4882 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4884 - CONFIG_SYS_OR_TIMING_SDRAM:
4887 - CONFIG_SYS_MAMR_PTA:
4888 periodic timer for refresh
4890 - CONFIG_SYS_DER: Debug Event Register (37-47)
4892 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4893 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4894 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4895 CONFIG_SYS_BR1_PRELIM:
4896 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4898 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4899 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4900 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4901 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4903 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4904 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4905 Machine Mode Register and Memory Periodic Timer
4906 Prescaler definitions (SDRAM timing)
4908 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4909 enable I2C microcode relocation patch (MPC8xx);
4910 define relocation offset in DPRAM [DSP2]
4912 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4913 enable SMC microcode relocation patch (MPC8xx);
4914 define relocation offset in DPRAM [SMC1]
4916 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4917 enable SPI microcode relocation patch (MPC8xx);
4918 define relocation offset in DPRAM [SCC4]
4920 - CONFIG_SYS_USE_OSCCLK:
4921 Use OSCM clock mode on MBX8xx board. Be careful,
4922 wrong setting might damage your board. Read
4923 doc/README.MBX before setting this variable!
4925 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4926 Offset of the bootmode word in DPRAM used by post
4927 (Power On Self Tests). This definition overrides
4928 #define'd default value in commproc.h resp.
4931 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4932 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4933 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4934 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4935 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4936 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4937 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4938 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4939 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4941 - CONFIG_PCI_DISABLE_PCIE:
4942 Disable PCI-Express on systems where it is supported but not
4945 - CONFIG_PCI_ENUM_ONLY
4946 Only scan through and get the devices on the buses.
4947 Don't do any setup work, presumably because someone or
4948 something has already done it, and we don't need to do it
4949 a second time. Useful for platforms that are pre-booted
4950 by coreboot or similar.
4952 - CONFIG_PCI_INDIRECT_BRIDGE:
4953 Enable support for indirect PCI bridges.
4956 Chip has SRIO or not
4959 Board has SRIO 1 port available
4962 Board has SRIO 2 port available
4964 - CONFIG_SRIO_PCIE_BOOT_MASTER
4965 Board can support master function for Boot from SRIO and PCIE
4967 - CONFIG_SYS_SRIOn_MEM_VIRT:
4968 Virtual Address of SRIO port 'n' memory region
4970 - CONFIG_SYS_SRIOn_MEM_PHYS:
4971 Physical Address of SRIO port 'n' memory region
4973 - CONFIG_SYS_SRIOn_MEM_SIZE:
4974 Size of SRIO port 'n' memory region
4976 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4977 Defined to tell the NAND controller that the NAND chip is using
4979 Not all NAND drivers use this symbol.
4980 Example of drivers that use it:
4981 - drivers/mtd/nand/ndfc.c
4982 - drivers/mtd/nand/mxc_nand.c
4984 - CONFIG_SYS_NDFC_EBC0_CFG
4985 Sets the EBC0_CFG register for the NDFC. If not defined
4986 a default value will be used.
4989 Get DDR timing information from an I2C EEPROM. Common
4990 with pluggable memory modules such as SODIMMs
4993 I2C address of the SPD EEPROM
4995 - CONFIG_SYS_SPD_BUS_NUM
4996 If SPD EEPROM is on an I2C bus other than the first
4997 one, specify here. Note that the value must resolve
4998 to something your driver can deal with.
5000 - CONFIG_SYS_DDR_RAW_TIMING
5001 Get DDR timing information from other than SPD. Common with
5002 soldered DDR chips onboard without SPD. DDR raw timing
5003 parameters are extracted from datasheet and hard-coded into
5004 header files or board specific files.
5006 - CONFIG_FSL_DDR_INTERACTIVE
5007 Enable interactive DDR debugging. See doc/README.fsl-ddr.
5009 - CONFIG_FSL_DDR_SYNC_REFRESH
5010 Enable sync of refresh for multiple controllers.
5012 - CONFIG_SYS_83XX_DDR_USES_CS0
5013 Only for 83xx systems. If specified, then DDR should
5014 be configured using CS0 and CS1 instead of CS2 and CS3.
5016 - CONFIG_ETHER_ON_FEC[12]
5017 Define to enable FEC[12] on a 8xx series processor.
5019 - CONFIG_FEC[12]_PHY
5020 Define to the hardcoded PHY address which corresponds
5021 to the given FEC; i. e.
5022 #define CONFIG_FEC1_PHY 4
5023 means that the PHY with address 4 is connected to FEC1
5025 When set to -1, means to probe for first available.
5027 - CONFIG_FEC[12]_PHY_NORXERR
5028 The PHY does not have a RXERR line (RMII only).
5029 (so program the FEC to ignore it).
5032 Enable RMII mode for all FECs.
5033 Note that this is a global option, we can't
5034 have one FEC in standard MII mode and another in RMII mode.
5036 - CONFIG_CRC32_VERIFY
5037 Add a verify option to the crc32 command.
5040 => crc32 -v <address> <count> <crc32>
5042 Where address/count indicate a memory area
5043 and crc32 is the correct crc32 which the
5047 Add the "loopw" memory command. This only takes effect if
5048 the memory commands are activated globally (CONFIG_CMD_MEM).
5051 Add the "mdc" and "mwc" memory commands. These are cyclic
5056 This command will print 4 bytes (10,11,12,13) each 500 ms.
5058 => mwc.l 100 12345678 10
5059 This command will write 12345678 to address 100 all 10 ms.
5061 This only takes effect if the memory commands are activated
5062 globally (CONFIG_CMD_MEM).
5064 - CONFIG_SKIP_LOWLEVEL_INIT
5065 [ARM, NDS32, MIPS only] If this variable is defined, then certain
5066 low level initializations (like setting up the memory
5067 controller) are omitted and/or U-Boot does not
5068 relocate itself into RAM.
5070 Normally this variable MUST NOT be defined. The only
5071 exception is when U-Boot is loaded (to RAM) by some
5072 other boot loader or by a debugger which performs
5073 these initializations itself.
5076 Modifies the behaviour of start.S when compiling a loader
5077 that is executed before the actual U-Boot. E.g. when
5078 compiling a NAND SPL.
5081 Modifies the behaviour of start.S when compiling a loader
5082 that is executed after the SPL and before the actual U-Boot.
5083 It is loaded by the SPL.
5085 - CONFIG_SYS_MPC85XX_NO_RESETVEC
5086 Only for 85xx systems. If this variable is specified, the section
5087 .resetvec is not kept and the section .bootpg is placed in the
5088 previous 4k of the .text section.
5090 - CONFIG_ARCH_MAP_SYSMEM
5091 Generally U-Boot (and in particular the md command) uses
5092 effective address. It is therefore not necessary to regard
5093 U-Boot address as virtual addresses that need to be translated
5094 to physical addresses. However, sandbox requires this, since
5095 it maintains its own little RAM buffer which contains all
5096 addressable memory. This option causes some memory accesses
5097 to be mapped through map_sysmem() / unmap_sysmem().
5099 - CONFIG_USE_ARCH_MEMCPY
5100 CONFIG_USE_ARCH_MEMSET
5101 If these options are used a optimized version of memcpy/memset will
5102 be used if available. These functions may be faster under some
5103 conditions but may increase the binary size.
5105 - CONFIG_X86_RESET_VECTOR
5106 If defined, the x86 reset vector code is included. This is not
5107 needed when U-Boot is running from Coreboot.
5110 Defines the MPU clock speed (in MHz).
5112 NOTE : currently only supported on AM335x platforms.
5114 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
5115 Enables the RTC32K OSC on AM33xx based plattforms
5117 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
5118 Option to disable subpage write in NAND driver
5119 driver that uses this:
5120 drivers/mtd/nand/davinci_nand.c
5122 Freescale QE/FMAN Firmware Support:
5123 -----------------------------------
5125 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
5126 loading of "firmware", which is encoded in the QE firmware binary format.
5127 This firmware often needs to be loaded during U-Boot booting, so macros
5128 are used to identify the storage device (NOR flash, SPI, etc) and the address
5131 - CONFIG_SYS_FMAN_FW_ADDR
5132 The address in the storage device where the FMAN microcode is located. The
5133 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
5136 - CONFIG_SYS_QE_FW_ADDR
5137 The address in the storage device where the QE microcode is located. The
5138 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
5141 - CONFIG_SYS_QE_FMAN_FW_LENGTH
5142 The maximum possible size of the firmware. The firmware binary format
5143 has a field that specifies the actual size of the firmware, but it
5144 might not be possible to read any part of the firmware unless some
5145 local storage is allocated to hold the entire firmware first.
5147 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
5148 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
5149 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
5150 virtual address in NOR flash.
5152 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
5153 Specifies that QE/FMAN firmware is located in NAND flash.
5154 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
5156 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
5157 Specifies that QE/FMAN firmware is located on the primary SD/MMC
5158 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
5160 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
5161 Specifies that QE/FMAN firmware is located on the primary SPI
5162 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
5164 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
5165 Specifies that QE/FMAN firmware is located in the remote (master)
5166 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
5167 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
5168 window->master inbound window->master LAW->the ucode address in
5169 master's memory space.
5171 Freescale Layerscape Management Complex Firmware Support:
5172 ---------------------------------------------------------
5173 The Freescale Layerscape Management Complex (MC) supports the loading of
5175 This firmware often needs to be loaded during U-Boot booting, so macros
5176 are used to identify the storage device (NOR flash, SPI, etc) and the address
5179 - CONFIG_FSL_MC_ENET
5180 Enable the MC driver for Layerscape SoCs.
5182 - CONFIG_SYS_LS_MC_FW_ADDR
5183 The address in the storage device where the firmware is located. The
5184 meaning of this address depends on which CONFIG_SYS_LS_MC_FW_IN_xxx macro
5187 - CONFIG_SYS_LS_MC_FW_LENGTH
5188 The maximum possible size of the firmware. The firmware binary format
5189 has a field that specifies the actual size of the firmware, but it
5190 might not be possible to read any part of the firmware unless some
5191 local storage is allocated to hold the entire firmware first.
5193 - CONFIG_SYS_LS_MC_FW_IN_NOR
5194 Specifies that MC firmware is located in NOR flash, mapped as
5195 normal addressable memory via the LBC. CONFIG_SYS_LS_MC_FW_ADDR is the
5196 virtual address in NOR flash.
5198 Building the Software:
5199 ======================
5201 Building U-Boot has been tested in several native build environments
5202 and in many different cross environments. Of course we cannot support
5203 all possibly existing versions of cross development tools in all
5204 (potentially obsolete) versions. In case of tool chain problems we
5205 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
5206 which is extensively used to build and test U-Boot.
5208 If you are not using a native environment, it is assumed that you
5209 have GNU cross compiling tools available in your path. In this case,
5210 you must set the environment variable CROSS_COMPILE in your shell.
5211 Note that no changes to the Makefile or any other source files are
5212 necessary. For example using the ELDK on a 4xx CPU, please enter:
5214 $ CROSS_COMPILE=ppc_4xx-
5215 $ export CROSS_COMPILE
5217 Note: If you wish to generate Windows versions of the utilities in
5218 the tools directory you can use the MinGW toolchain
5219 (http://www.mingw.org). Set your HOST tools to the MinGW
5220 toolchain and execute 'make tools'. For example:
5222 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
5224 Binaries such as tools/mkimage.exe will be created which can
5225 be executed on computers running Windows.
5227 U-Boot is intended to be simple to build. After installing the
5228 sources you must configure U-Boot for one specific board type. This
5233 where "NAME_defconfig" is the name of one of the existing configu-
5234 rations; see boards.cfg for supported names.
5236 Note: for some board special configuration names may exist; check if
5237 additional information is available from the board vendor; for
5238 instance, the TQM823L systems are available without (standard)
5239 or with LCD support. You can select such additional "features"
5240 when choosing the configuration, i. e.
5242 make TQM823L_defconfig
5243 - will configure for a plain TQM823L, i. e. no LCD support
5245 make TQM823L_LCD_defconfig
5246 - will configure for a TQM823L with U-Boot console on LCD
5251 Finally, type "make all", and you should get some working U-Boot
5252 images ready for download to / installation on your system:
5254 - "u-boot.bin" is a raw binary image
5255 - "u-boot" is an image in ELF binary format
5256 - "u-boot.srec" is in Motorola S-Record format
5258 By default the build is performed locally and the objects are saved
5259 in the source directory. One of the two methods can be used to change
5260 this behavior and build U-Boot to some external directory:
5262 1. Add O= to the make command line invocations:
5264 make O=/tmp/build distclean
5265 make O=/tmp/build NAME_defconfig
5266 make O=/tmp/build all
5268 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
5270 export KBUILD_OUTPUT=/tmp/build
5275 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
5279 Please be aware that the Makefiles assume you are using GNU make, so
5280 for instance on NetBSD you might need to use "gmake" instead of
5284 If the system board that you have is not listed, then you will need
5285 to port U-Boot to your hardware platform. To do this, follow these
5288 1. Add a new configuration option for your board to the toplevel
5289 "boards.cfg" file, using the existing entries as examples.
5290 Follow the instructions there to keep the boards in order.
5291 2. Create a new directory to hold your board specific code. Add any
5292 files you need. In your board directory, you will need at least
5293 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
5294 3. Create a new configuration file "include/configs/<board>.h" for
5296 3. If you're porting U-Boot to a new CPU, then also create a new
5297 directory to hold your CPU specific code. Add any files you need.
5298 4. Run "make <board>_defconfig" with your new name.
5299 5. Type "make", and you should get a working "u-boot.srec" file
5300 to be installed on your target system.
5301 6. Debug and solve any problems that might arise.
5302 [Of course, this last step is much harder than it sounds.]
5305 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
5306 ==============================================================
5308 If you have modified U-Boot sources (for instance added a new board
5309 or support for new devices, a new CPU, etc.) you are expected to
5310 provide feedback to the other developers. The feedback normally takes
5311 the form of a "patch", i. e. a context diff against a certain (latest
5312 official or latest in the git repository) version of U-Boot sources.
5314 But before you submit such a patch, please verify that your modifi-
5315 cation did not break existing code. At least make sure that *ALL* of
5316 the supported boards compile WITHOUT ANY compiler warnings. To do so,
5317 just run the "MAKEALL" script, which will configure and build U-Boot
5318 for ALL supported system. Be warned, this will take a while. You can
5319 select which (cross) compiler to use by passing a `CROSS_COMPILE'
5320 environment variable to the script, i. e. to use the ELDK cross tools
5323 CROSS_COMPILE=ppc_8xx- MAKEALL
5325 or to build on a native PowerPC system you can type
5327 CROSS_COMPILE=' ' MAKEALL
5329 When using the MAKEALL script, the default behaviour is to build
5330 U-Boot in the source directory. This location can be changed by
5331 setting the BUILD_DIR environment variable. Also, for each target
5332 built, the MAKEALL script saves two log files (<target>.ERR and
5333 <target>.MAKEALL) in the <source dir>/LOG directory. This default
5334 location can be changed by setting the MAKEALL_LOGDIR environment
5335 variable. For example:
5337 export BUILD_DIR=/tmp/build
5338 export MAKEALL_LOGDIR=/tmp/log
5339 CROSS_COMPILE=ppc_8xx- MAKEALL
5341 With the above settings build objects are saved in the /tmp/build,
5342 log files are saved in the /tmp/log and the source tree remains clean
5343 during the whole build process.
5346 See also "U-Boot Porting Guide" below.
5349 Monitor Commands - Overview:
5350 ============================
5352 go - start application at address 'addr'
5353 run - run commands in an environment variable
5354 bootm - boot application image from memory
5355 bootp - boot image via network using BootP/TFTP protocol
5356 bootz - boot zImage from memory
5357 tftpboot- boot image via network using TFTP protocol
5358 and env variables "ipaddr" and "serverip"
5359 (and eventually "gatewayip")
5360 tftpput - upload a file via network using TFTP protocol
5361 rarpboot- boot image via network using RARP/TFTP protocol
5362 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
5363 loads - load S-Record file over serial line
5364 loadb - load binary file over serial line (kermit mode)
5366 mm - memory modify (auto-incrementing)
5367 nm - memory modify (constant address)
5368 mw - memory write (fill)
5370 cmp - memory compare
5371 crc32 - checksum calculation
5372 i2c - I2C sub-system
5373 sspi - SPI utility commands
5374 base - print or set address offset
5375 printenv- print environment variables
5376 setenv - set environment variables
5377 saveenv - save environment variables to persistent storage
5378 protect - enable or disable FLASH write protection
5379 erase - erase FLASH memory
5380 flinfo - print FLASH memory information
5381 nand - NAND memory operations (see doc/README.nand)
5382 bdinfo - print Board Info structure
5383 iminfo - print header information for application image
5384 coninfo - print console devices and informations
5385 ide - IDE sub-system
5386 loop - infinite loop on address range
5387 loopw - infinite write loop on address range
5388 mtest - simple RAM test
5389 icache - enable or disable instruction cache
5390 dcache - enable or disable data cache
5391 reset - Perform RESET of the CPU
5392 echo - echo args to console
5393 version - print monitor version
5394 help - print online help
5395 ? - alias for 'help'
5398 Monitor Commands - Detailed Description:
5399 ========================================
5403 For now: just type "help <command>".
5406 Environment Variables:
5407 ======================
5409 U-Boot supports user configuration using Environment Variables which
5410 can be made persistent by saving to Flash memory.
5412 Environment Variables are set using "setenv", printed using
5413 "printenv", and saved to Flash using "saveenv". Using "setenv"
5414 without a value can be used to delete a variable from the
5415 environment. As long as you don't save the environment you are
5416 working with an in-memory copy. In case the Flash area containing the
5417 environment is erased by accident, a default environment is provided.
5419 Some configuration options can be set using Environment Variables.
5421 List of environment variables (most likely not complete):
5423 baudrate - see CONFIG_BAUDRATE
5425 bootdelay - see CONFIG_BOOTDELAY
5427 bootcmd - see CONFIG_BOOTCOMMAND
5429 bootargs - Boot arguments when booting an RTOS image
5431 bootfile - Name of the image to load with TFTP
5433 bootm_low - Memory range available for image processing in the bootm
5434 command can be restricted. This variable is given as
5435 a hexadecimal number and defines lowest address allowed
5436 for use by the bootm command. See also "bootm_size"
5437 environment variable. Address defined by "bootm_low" is
5438 also the base of the initial memory mapping for the Linux
5439 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
5442 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
5443 This variable is given as a hexadecimal number and it
5444 defines the size of the memory region starting at base
5445 address bootm_low that is accessible by the Linux kernel
5446 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
5447 as the default value if it is defined, and bootm_size is
5450 bootm_size - Memory range available for image processing in the bootm
5451 command can be restricted. This variable is given as
5452 a hexadecimal number and defines the size of the region
5453 allowed for use by the bootm command. See also "bootm_low"
5454 environment variable.
5456 updatefile - Location of the software update file on a TFTP server, used
5457 by the automatic software update feature. Please refer to
5458 documentation in doc/README.update for more details.
5460 autoload - if set to "no" (any string beginning with 'n'),
5461 "bootp" will just load perform a lookup of the
5462 configuration from the BOOTP server, but not try to
5463 load any image using TFTP
5465 autostart - if set to "yes", an image loaded using the "bootp",
5466 "rarpboot", "tftpboot" or "diskboot" commands will
5467 be automatically started (by internally calling
5470 If set to "no", a standalone image passed to the
5471 "bootm" command will be copied to the load address
5472 (and eventually uncompressed), but NOT be started.
5473 This can be used to load and uncompress arbitrary
5476 fdt_high - if set this restricts the maximum address that the
5477 flattened device tree will be copied into upon boot.
5478 For example, if you have a system with 1 GB memory
5479 at physical address 0x10000000, while Linux kernel
5480 only recognizes the first 704 MB as low memory, you
5481 may need to set fdt_high as 0x3C000000 to have the
5482 device tree blob be copied to the maximum address
5483 of the 704 MB low memory, so that Linux kernel can
5484 access it during the boot procedure.
5486 If this is set to the special value 0xFFFFFFFF then
5487 the fdt will not be copied at all on boot. For this
5488 to work it must reside in writable memory, have
5489 sufficient padding on the end of it for u-boot to
5490 add the information it needs into it, and the memory
5491 must be accessible by the kernel.
5493 fdtcontroladdr- if set this is the address of the control flattened
5494 device tree used by U-Boot when CONFIG_OF_CONTROL is
5497 i2cfast - (PPC405GP|PPC405EP only)
5498 if set to 'y' configures Linux I2C driver for fast
5499 mode (400kHZ). This environment variable is used in
5500 initialization code. So, for changes to be effective
5501 it must be saved and board must be reset.
5503 initrd_high - restrict positioning of initrd images:
5504 If this variable is not set, initrd images will be
5505 copied to the highest possible address in RAM; this
5506 is usually what you want since it allows for
5507 maximum initrd size. If for some reason you want to
5508 make sure that the initrd image is loaded below the
5509 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
5510 variable to a value of "no" or "off" or "0".
5511 Alternatively, you can set it to a maximum upper
5512 address to use (U-Boot will still check that it
5513 does not overwrite the U-Boot stack and data).
5515 For instance, when you have a system with 16 MB
5516 RAM, and want to reserve 4 MB from use by Linux,
5517 you can do this by adding "mem=12M" to the value of
5518 the "bootargs" variable. However, now you must make
5519 sure that the initrd image is placed in the first
5520 12 MB as well - this can be done with
5522 setenv initrd_high 00c00000
5524 If you set initrd_high to 0xFFFFFFFF, this is an
5525 indication to U-Boot that all addresses are legal
5526 for the Linux kernel, including addresses in flash
5527 memory. In this case U-Boot will NOT COPY the
5528 ramdisk at all. This may be useful to reduce the
5529 boot time on your system, but requires that this
5530 feature is supported by your Linux kernel.
5532 ipaddr - IP address; needed for tftpboot command
5534 loadaddr - Default load address for commands like "bootp",
5535 "rarpboot", "tftpboot", "loadb" or "diskboot"
5537 loads_echo - see CONFIG_LOADS_ECHO
5539 serverip - TFTP server IP address; needed for tftpboot command
5541 bootretry - see CONFIG_BOOT_RETRY_TIME
5543 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
5545 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
5547 ethprime - controls which interface is used first.
5549 ethact - controls which interface is currently active.
5550 For example you can do the following
5552 => setenv ethact FEC
5553 => ping 192.168.0.1 # traffic sent on FEC
5554 => setenv ethact SCC
5555 => ping 10.0.0.1 # traffic sent on SCC
5557 ethrotate - When set to "no" U-Boot does not go through all
5558 available network interfaces.
5559 It just stays at the currently selected interface.
5561 netretry - When set to "no" each network operation will
5562 either succeed or fail without retrying.
5563 When set to "once" the network operation will
5564 fail when all the available network interfaces
5565 are tried once without success.
5566 Useful on scripts which control the retry operation
5569 npe_ucode - set load address for the NPE microcode
5571 silent_linux - If set then Linux will be told to boot silently, by
5572 changing the console to be empty. If "yes" it will be
5573 made silent. If "no" it will not be made silent. If
5574 unset, then it will be made silent if the U-Boot console
5577 tftpsrcport - If this is set, the value is used for TFTP's
5580 tftpdstport - If this is set, the value is used for TFTP's UDP
5581 destination port instead of the Well Know Port 69.
5583 tftpblocksize - Block size to use for TFTP transfers; if not set,
5584 we use the TFTP server's default block size
5586 tftptimeout - Retransmission timeout for TFTP packets (in milli-
5587 seconds, minimum value is 1000 = 1 second). Defines
5588 when a packet is considered to be lost so it has to
5589 be retransmitted. The default is 5000 = 5 seconds.
5590 Lowering this value may make downloads succeed
5591 faster in networks with high packet loss rates or
5592 with unreliable TFTP servers.
5594 vlan - When set to a value < 4095 the traffic over
5595 Ethernet is encapsulated/received over 802.1q
5598 The following image location variables contain the location of images
5599 used in booting. The "Image" column gives the role of the image and is
5600 not an environment variable name. The other columns are environment
5601 variable names. "File Name" gives the name of the file on a TFTP
5602 server, "RAM Address" gives the location in RAM the image will be
5603 loaded to, and "Flash Location" gives the image's address in NOR
5604 flash or offset in NAND flash.
5606 *Note* - these variables don't have to be defined for all boards, some
5607 boards currenlty use other variables for these purposes, and some
5608 boards use these variables for other purposes.
5610 Image File Name RAM Address Flash Location
5611 ----- --------- ----------- --------------
5612 u-boot u-boot u-boot_addr_r u-boot_addr
5613 Linux kernel bootfile kernel_addr_r kernel_addr
5614 device tree blob fdtfile fdt_addr_r fdt_addr
5615 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5617 The following environment variables may be used and automatically
5618 updated by the network boot commands ("bootp" and "rarpboot"),
5619 depending the information provided by your boot server:
5621 bootfile - see above
5622 dnsip - IP address of your Domain Name Server
5623 dnsip2 - IP address of your secondary Domain Name Server
5624 gatewayip - IP address of the Gateway (Router) to use
5625 hostname - Target hostname
5627 netmask - Subnet Mask
5628 rootpath - Pathname of the root filesystem on the NFS server
5629 serverip - see above
5632 There are two special Environment Variables:
5634 serial# - contains hardware identification information such
5635 as type string and/or serial number
5636 ethaddr - Ethernet address
5638 These variables can be set only once (usually during manufacturing of
5639 the board). U-Boot refuses to delete or overwrite these variables
5640 once they have been set once.
5643 Further special Environment Variables:
5645 ver - Contains the U-Boot version string as printed
5646 with the "version" command. This variable is
5647 readonly (see CONFIG_VERSION_VARIABLE).
5650 Please note that changes to some configuration parameters may take
5651 only effect after the next boot (yes, that's just like Windoze :-).
5654 Callback functions for environment variables:
5655 ---------------------------------------------
5657 For some environment variables, the behavior of u-boot needs to change
5658 when their values are changed. This functionality allows functions to
5659 be associated with arbitrary variables. On creation, overwrite, or
5660 deletion, the callback will provide the opportunity for some side
5661 effect to happen or for the change to be rejected.
5663 The callbacks are named and associated with a function using the
5664 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5666 These callbacks are associated with variables in one of two ways. The
5667 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5668 in the board configuration to a string that defines a list of
5669 associations. The list must be in the following format:
5671 entry = variable_name[:callback_name]
5674 If the callback name is not specified, then the callback is deleted.
5675 Spaces are also allowed anywhere in the list.
5677 Callbacks can also be associated by defining the ".callbacks" variable
5678 with the same list format above. Any association in ".callbacks" will
5679 override any association in the static list. You can define
5680 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5681 ".callbacks" environment variable in the default or embedded environment.
5684 Command Line Parsing:
5685 =====================
5687 There are two different command line parsers available with U-Boot:
5688 the old "simple" one, and the much more powerful "hush" shell:
5690 Old, simple command line parser:
5691 --------------------------------
5693 - supports environment variables (through setenv / saveenv commands)
5694 - several commands on one line, separated by ';'
5695 - variable substitution using "... ${name} ..." syntax
5696 - special characters ('$', ';') can be escaped by prefixing with '\',
5698 setenv bootcmd bootm \${address}
5699 - You can also escape text by enclosing in single apostrophes, for example:
5700 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5705 - similar to Bourne shell, with control structures like
5706 if...then...else...fi, for...do...done; while...do...done,
5707 until...do...done, ...
5708 - supports environment ("global") variables (through setenv / saveenv
5709 commands) and local shell variables (through standard shell syntax
5710 "name=value"); only environment variables can be used with "run"
5716 (1) If a command line (or an environment variable executed by a "run"
5717 command) contains several commands separated by semicolon, and
5718 one of these commands fails, then the remaining commands will be
5721 (2) If you execute several variables with one call to run (i. e.
5722 calling run with a list of variables as arguments), any failing
5723 command will cause "run" to terminate, i. e. the remaining
5724 variables are not executed.
5726 Note for Redundant Ethernet Interfaces:
5727 =======================================
5729 Some boards come with redundant Ethernet interfaces; U-Boot supports
5730 such configurations and is capable of automatic selection of a
5731 "working" interface when needed. MAC assignment works as follows:
5733 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5734 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5735 "eth1addr" (=>eth1), "eth2addr", ...
5737 If the network interface stores some valid MAC address (for instance
5738 in SROM), this is used as default address if there is NO correspon-
5739 ding setting in the environment; if the corresponding environment
5740 variable is set, this overrides the settings in the card; that means:
5742 o If the SROM has a valid MAC address, and there is no address in the
5743 environment, the SROM's address is used.
5745 o If there is no valid address in the SROM, and a definition in the
5746 environment exists, then the value from the environment variable is
5749 o If both the SROM and the environment contain a MAC address, and
5750 both addresses are the same, this MAC address is used.
5752 o If both the SROM and the environment contain a MAC address, and the
5753 addresses differ, the value from the environment is used and a
5756 o If neither SROM nor the environment contain a MAC address, an error
5759 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5760 will be programmed into hardware as part of the initialization process. This
5761 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5762 The naming convention is as follows:
5763 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5768 U-Boot is capable of booting (and performing other auxiliary operations on)
5769 images in two formats:
5771 New uImage format (FIT)
5772 -----------------------
5774 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5775 to Flattened Device Tree). It allows the use of images with multiple
5776 components (several kernels, ramdisks, etc.), with contents protected by
5777 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5783 Old image format is based on binary files which can be basically anything,
5784 preceded by a special header; see the definitions in include/image.h for
5785 details; basically, the header defines the following image properties:
5787 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5788 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5789 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5790 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5792 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5793 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5794 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5795 * Compression Type (uncompressed, gzip, bzip2)
5801 The header is marked by a special Magic Number, and both the header
5802 and the data portions of the image are secured against corruption by
5809 Although U-Boot should support any OS or standalone application
5810 easily, the main focus has always been on Linux during the design of
5813 U-Boot includes many features that so far have been part of some
5814 special "boot loader" code within the Linux kernel. Also, any
5815 "initrd" images to be used are no longer part of one big Linux image;
5816 instead, kernel and "initrd" are separate images. This implementation
5817 serves several purposes:
5819 - the same features can be used for other OS or standalone
5820 applications (for instance: using compressed images to reduce the
5821 Flash memory footprint)
5823 - it becomes much easier to port new Linux kernel versions because
5824 lots of low-level, hardware dependent stuff are done by U-Boot
5826 - the same Linux kernel image can now be used with different "initrd"
5827 images; of course this also means that different kernel images can
5828 be run with the same "initrd". This makes testing easier (you don't
5829 have to build a new "zImage.initrd" Linux image when you just
5830 change a file in your "initrd"). Also, a field-upgrade of the
5831 software is easier now.
5837 Porting Linux to U-Boot based systems:
5838 ---------------------------------------
5840 U-Boot cannot save you from doing all the necessary modifications to
5841 configure the Linux device drivers for use with your target hardware
5842 (no, we don't intend to provide a full virtual machine interface to
5845 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5847 Just make sure your machine specific header file (for instance
5848 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5849 Information structure as we define in include/asm-<arch>/u-boot.h,
5850 and make sure that your definition of IMAP_ADDR uses the same value
5851 as your U-Boot configuration in CONFIG_SYS_IMMR.
5853 Note that U-Boot now has a driver model, a unified model for drivers.
5854 If you are adding a new driver, plumb it into driver model. If there
5855 is no uclass available, you are encouraged to create one. See
5859 Configuring the Linux kernel:
5860 -----------------------------
5862 No specific requirements for U-Boot. Make sure you have some root
5863 device (initial ramdisk, NFS) for your target system.
5866 Building a Linux Image:
5867 -----------------------
5869 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5870 not used. If you use recent kernel source, a new build target
5871 "uImage" will exist which automatically builds an image usable by
5872 U-Boot. Most older kernels also have support for a "pImage" target,
5873 which was introduced for our predecessor project PPCBoot and uses a
5874 100% compatible format.
5878 make TQM850L_defconfig
5883 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5884 encapsulate a compressed Linux kernel image with header information,
5885 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5887 * build a standard "vmlinux" kernel image (in ELF binary format):
5889 * convert the kernel into a raw binary image:
5891 ${CROSS_COMPILE}-objcopy -O binary \
5892 -R .note -R .comment \
5893 -S vmlinux linux.bin
5895 * compress the binary image:
5899 * package compressed binary image for U-Boot:
5901 mkimage -A ppc -O linux -T kernel -C gzip \
5902 -a 0 -e 0 -n "Linux Kernel Image" \
5903 -d linux.bin.gz uImage
5906 The "mkimage" tool can also be used to create ramdisk images for use
5907 with U-Boot, either separated from the Linux kernel image, or
5908 combined into one file. "mkimage" encapsulates the images with a 64
5909 byte header containing information about target architecture,
5910 operating system, image type, compression method, entry points, time
5911 stamp, CRC32 checksums, etc.
5913 "mkimage" can be called in two ways: to verify existing images and
5914 print the header information, or to build new images.
5916 In the first form (with "-l" option) mkimage lists the information
5917 contained in the header of an existing U-Boot image; this includes
5918 checksum verification:
5920 tools/mkimage -l image
5921 -l ==> list image header information
5923 The second form (with "-d" option) is used to build a U-Boot image
5924 from a "data file" which is used as image payload:
5926 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5927 -n name -d data_file image
5928 -A ==> set architecture to 'arch'
5929 -O ==> set operating system to 'os'
5930 -T ==> set image type to 'type'
5931 -C ==> set compression type 'comp'
5932 -a ==> set load address to 'addr' (hex)
5933 -e ==> set entry point to 'ep' (hex)
5934 -n ==> set image name to 'name'
5935 -d ==> use image data from 'datafile'
5937 Right now, all Linux kernels for PowerPC systems use the same load
5938 address (0x00000000), but the entry point address depends on the
5941 - 2.2.x kernels have the entry point at 0x0000000C,
5942 - 2.3.x and later kernels have the entry point at 0x00000000.
5944 So a typical call to build a U-Boot image would read:
5946 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5947 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5948 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5949 > examples/uImage.TQM850L
5950 Image Name: 2.4.4 kernel for TQM850L
5951 Created: Wed Jul 19 02:34:59 2000
5952 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5953 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5954 Load Address: 0x00000000
5955 Entry Point: 0x00000000
5957 To verify the contents of the image (or check for corruption):
5959 -> tools/mkimage -l examples/uImage.TQM850L
5960 Image Name: 2.4.4 kernel for TQM850L
5961 Created: Wed Jul 19 02:34:59 2000
5962 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5963 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5964 Load Address: 0x00000000
5965 Entry Point: 0x00000000
5967 NOTE: for embedded systems where boot time is critical you can trade
5968 speed for memory and install an UNCOMPRESSED image instead: this
5969 needs more space in Flash, but boots much faster since it does not
5970 need to be uncompressed:
5972 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5973 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5974 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5975 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5976 > examples/uImage.TQM850L-uncompressed
5977 Image Name: 2.4.4 kernel for TQM850L
5978 Created: Wed Jul 19 02:34:59 2000
5979 Image Type: PowerPC Linux Kernel Image (uncompressed)
5980 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5981 Load Address: 0x00000000
5982 Entry Point: 0x00000000
5985 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5986 when your kernel is intended to use an initial ramdisk:
5988 -> tools/mkimage -n 'Simple Ramdisk Image' \
5989 > -A ppc -O linux -T ramdisk -C gzip \
5990 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5991 Image Name: Simple Ramdisk Image
5992 Created: Wed Jan 12 14:01:50 2000
5993 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5994 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5995 Load Address: 0x00000000
5996 Entry Point: 0x00000000
5998 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5999 option performs the converse operation of the mkimage's second form (the "-d"
6000 option). Given an image built by mkimage, the dumpimage extracts a "data file"
6003 tools/dumpimage -i image -T type -p position data_file
6004 -i ==> extract from the 'image' a specific 'data_file'
6005 -T ==> set image type to 'type'
6006 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
6009 Installing a Linux Image:
6010 -------------------------
6012 To downloading a U-Boot image over the serial (console) interface,
6013 you must convert the image to S-Record format:
6015 objcopy -I binary -O srec examples/image examples/image.srec
6017 The 'objcopy' does not understand the information in the U-Boot
6018 image header, so the resulting S-Record file will be relative to
6019 address 0x00000000. To load it to a given address, you need to
6020 specify the target address as 'offset' parameter with the 'loads'
6023 Example: install the image to address 0x40100000 (which on the
6024 TQM8xxL is in the first Flash bank):
6026 => erase 40100000 401FFFFF
6032 ## Ready for S-Record download ...
6033 ~>examples/image.srec
6034 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
6036 15989 15990 15991 15992
6037 [file transfer complete]
6039 ## Start Addr = 0x00000000
6042 You can check the success of the download using the 'iminfo' command;
6043 this includes a checksum verification so you can be sure no data
6044 corruption happened:
6048 ## Checking Image at 40100000 ...
6049 Image Name: 2.2.13 for initrd on TQM850L
6050 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6051 Data Size: 335725 Bytes = 327 kB = 0 MB
6052 Load Address: 00000000
6053 Entry Point: 0000000c
6054 Verifying Checksum ... OK
6060 The "bootm" command is used to boot an application that is stored in
6061 memory (RAM or Flash). In case of a Linux kernel image, the contents
6062 of the "bootargs" environment variable is passed to the kernel as
6063 parameters. You can check and modify this variable using the
6064 "printenv" and "setenv" commands:
6067 => printenv bootargs
6068 bootargs=root=/dev/ram
6070 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
6072 => printenv bootargs
6073 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
6076 ## Booting Linux kernel at 40020000 ...
6077 Image Name: 2.2.13 for NFS on TQM850L
6078 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6079 Data Size: 381681 Bytes = 372 kB = 0 MB
6080 Load Address: 00000000
6081 Entry Point: 0000000c
6082 Verifying Checksum ... OK
6083 Uncompressing Kernel Image ... OK
6084 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
6085 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
6086 time_init: decrementer frequency = 187500000/60
6087 Calibrating delay loop... 49.77 BogoMIPS
6088 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
6091 If you want to boot a Linux kernel with initial RAM disk, you pass
6092 the memory addresses of both the kernel and the initrd image (PPBCOOT
6093 format!) to the "bootm" command:
6095 => imi 40100000 40200000
6097 ## Checking Image at 40100000 ...
6098 Image Name: 2.2.13 for initrd on TQM850L
6099 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6100 Data Size: 335725 Bytes = 327 kB = 0 MB
6101 Load Address: 00000000
6102 Entry Point: 0000000c
6103 Verifying Checksum ... OK
6105 ## Checking Image at 40200000 ...
6106 Image Name: Simple Ramdisk Image
6107 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
6108 Data Size: 566530 Bytes = 553 kB = 0 MB
6109 Load Address: 00000000
6110 Entry Point: 00000000
6111 Verifying Checksum ... OK
6113 => bootm 40100000 40200000
6114 ## Booting Linux kernel at 40100000 ...
6115 Image Name: 2.2.13 for initrd on TQM850L
6116 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6117 Data Size: 335725 Bytes = 327 kB = 0 MB
6118 Load Address: 00000000
6119 Entry Point: 0000000c
6120 Verifying Checksum ... OK
6121 Uncompressing Kernel Image ... OK
6122 ## Loading RAMDisk Image at 40200000 ...
6123 Image Name: Simple Ramdisk Image
6124 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
6125 Data Size: 566530 Bytes = 553 kB = 0 MB
6126 Load Address: 00000000
6127 Entry Point: 00000000
6128 Verifying Checksum ... OK
6129 Loading Ramdisk ... OK
6130 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
6131 Boot arguments: root=/dev/ram
6132 time_init: decrementer frequency = 187500000/60
6133 Calibrating delay loop... 49.77 BogoMIPS
6135 RAMDISK: Compressed image found at block 0
6136 VFS: Mounted root (ext2 filesystem).
6140 Boot Linux and pass a flat device tree:
6143 First, U-Boot must be compiled with the appropriate defines. See the section
6144 titled "Linux Kernel Interface" above for a more in depth explanation. The
6145 following is an example of how to start a kernel and pass an updated
6151 oft=oftrees/mpc8540ads.dtb
6152 => tftp $oftaddr $oft
6153 Speed: 1000, full duplex
6155 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
6156 Filename 'oftrees/mpc8540ads.dtb'.
6157 Load address: 0x300000
6160 Bytes transferred = 4106 (100a hex)
6161 => tftp $loadaddr $bootfile
6162 Speed: 1000, full duplex
6164 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
6166 Load address: 0x200000
6167 Loading:############
6169 Bytes transferred = 1029407 (fb51f hex)
6174 => bootm $loadaddr - $oftaddr
6175 ## Booting image at 00200000 ...
6176 Image Name: Linux-2.6.17-dirty
6177 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6178 Data Size: 1029343 Bytes = 1005.2 kB
6179 Load Address: 00000000
6180 Entry Point: 00000000
6181 Verifying Checksum ... OK
6182 Uncompressing Kernel Image ... OK
6183 Booting using flat device tree at 0x300000
6184 Using MPC85xx ADS machine description
6185 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
6189 More About U-Boot Image Types:
6190 ------------------------------
6192 U-Boot supports the following image types:
6194 "Standalone Programs" are directly runnable in the environment
6195 provided by U-Boot; it is expected that (if they behave
6196 well) you can continue to work in U-Boot after return from
6197 the Standalone Program.
6198 "OS Kernel Images" are usually images of some Embedded OS which
6199 will take over control completely. Usually these programs
6200 will install their own set of exception handlers, device
6201 drivers, set up the MMU, etc. - this means, that you cannot
6202 expect to re-enter U-Boot except by resetting the CPU.
6203 "RAMDisk Images" are more or less just data blocks, and their
6204 parameters (address, size) are passed to an OS kernel that is
6206 "Multi-File Images" contain several images, typically an OS
6207 (Linux) kernel image and one or more data images like
6208 RAMDisks. This construct is useful for instance when you want
6209 to boot over the network using BOOTP etc., where the boot
6210 server provides just a single image file, but you want to get
6211 for instance an OS kernel and a RAMDisk image.
6213 "Multi-File Images" start with a list of image sizes, each
6214 image size (in bytes) specified by an "uint32_t" in network
6215 byte order. This list is terminated by an "(uint32_t)0".
6216 Immediately after the terminating 0 follow the images, one by
6217 one, all aligned on "uint32_t" boundaries (size rounded up to
6218 a multiple of 4 bytes).
6220 "Firmware Images" are binary images containing firmware (like
6221 U-Boot or FPGA images) which usually will be programmed to
6224 "Script files" are command sequences that will be executed by
6225 U-Boot's command interpreter; this feature is especially
6226 useful when you configure U-Boot to use a real shell (hush)
6227 as command interpreter.
6229 Booting the Linux zImage:
6230 -------------------------
6232 On some platforms, it's possible to boot Linux zImage. This is done
6233 using the "bootz" command. The syntax of "bootz" command is the same
6234 as the syntax of "bootm" command.
6236 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
6237 kernel with raw initrd images. The syntax is slightly different, the
6238 address of the initrd must be augmented by it's size, in the following
6239 format: "<initrd addres>:<initrd size>".
6245 One of the features of U-Boot is that you can dynamically load and
6246 run "standalone" applications, which can use some resources of
6247 U-Boot like console I/O functions or interrupt services.
6249 Two simple examples are included with the sources:
6254 'examples/hello_world.c' contains a small "Hello World" Demo
6255 application; it is automatically compiled when you build U-Boot.
6256 It's configured to run at address 0x00040004, so you can play with it
6260 ## Ready for S-Record download ...
6261 ~>examples/hello_world.srec
6262 1 2 3 4 5 6 7 8 9 10 11 ...
6263 [file transfer complete]
6265 ## Start Addr = 0x00040004
6267 => go 40004 Hello World! This is a test.
6268 ## Starting application at 0x00040004 ...
6279 Hit any key to exit ...
6281 ## Application terminated, rc = 0x0
6283 Another example, which demonstrates how to register a CPM interrupt
6284 handler with the U-Boot code, can be found in 'examples/timer.c'.
6285 Here, a CPM timer is set up to generate an interrupt every second.
6286 The interrupt service routine is trivial, just printing a '.'
6287 character, but this is just a demo program. The application can be
6288 controlled by the following keys:
6290 ? - print current values og the CPM Timer registers
6291 b - enable interrupts and start timer
6292 e - stop timer and disable interrupts
6293 q - quit application
6296 ## Ready for S-Record download ...
6297 ~>examples/timer.srec
6298 1 2 3 4 5 6 7 8 9 10 11 ...
6299 [file transfer complete]
6301 ## Start Addr = 0x00040004
6304 ## Starting application at 0x00040004 ...
6307 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
6310 [q, b, e, ?] Set interval 1000000 us
6313 [q, b, e, ?] ........
6314 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
6317 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
6320 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
6323 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
6325 [q, b, e, ?] ...Stopping timer
6327 [q, b, e, ?] ## Application terminated, rc = 0x0
6333 Over time, many people have reported problems when trying to use the
6334 "minicom" terminal emulation program for serial download. I (wd)
6335 consider minicom to be broken, and recommend not to use it. Under
6336 Unix, I recommend to use C-Kermit for general purpose use (and
6337 especially for kermit binary protocol download ("loadb" command), and
6338 use "cu" for S-Record download ("loads" command). See
6339 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
6340 for help with kermit.
6343 Nevertheless, if you absolutely want to use it try adding this
6344 configuration to your "File transfer protocols" section:
6346 Name Program Name U/D FullScr IO-Red. Multi
6347 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
6348 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
6354 Starting at version 0.9.2, U-Boot supports NetBSD both as host
6355 (build U-Boot) and target system (boots NetBSD/mpc8xx).
6357 Building requires a cross environment; it is known to work on
6358 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
6359 need gmake since the Makefiles are not compatible with BSD make).
6360 Note that the cross-powerpc package does not install include files;
6361 attempting to build U-Boot will fail because <machine/ansi.h> is
6362 missing. This file has to be installed and patched manually:
6364 # cd /usr/pkg/cross/powerpc-netbsd/include
6366 # ln -s powerpc machine
6367 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
6368 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
6370 Native builds *don't* work due to incompatibilities between native
6371 and U-Boot include files.
6373 Booting assumes that (the first part of) the image booted is a
6374 stage-2 loader which in turn loads and then invokes the kernel
6375 proper. Loader sources will eventually appear in the NetBSD source
6376 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
6377 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
6380 Implementation Internals:
6381 =========================
6383 The following is not intended to be a complete description of every
6384 implementation detail. However, it should help to understand the
6385 inner workings of U-Boot and make it easier to port it to custom
6389 Initial Stack, Global Data:
6390 ---------------------------
6392 The implementation of U-Boot is complicated by the fact that U-Boot
6393 starts running out of ROM (flash memory), usually without access to
6394 system RAM (because the memory controller is not initialized yet).
6395 This means that we don't have writable Data or BSS segments, and BSS
6396 is not initialized as zero. To be able to get a C environment working
6397 at all, we have to allocate at least a minimal stack. Implementation
6398 options for this are defined and restricted by the CPU used: Some CPU
6399 models provide on-chip memory (like the IMMR area on MPC8xx and
6400 MPC826x processors), on others (parts of) the data cache can be
6401 locked as (mis-) used as memory, etc.
6403 Chris Hallinan posted a good summary of these issues to the
6404 U-Boot mailing list:
6406 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
6407 From: "Chris Hallinan" <clh@net1plus.com>
6408 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
6411 Correct me if I'm wrong, folks, but the way I understand it
6412 is this: Using DCACHE as initial RAM for Stack, etc, does not
6413 require any physical RAM backing up the cache. The cleverness
6414 is that the cache is being used as a temporary supply of
6415 necessary storage before the SDRAM controller is setup. It's
6416 beyond the scope of this list to explain the details, but you
6417 can see how this works by studying the cache architecture and
6418 operation in the architecture and processor-specific manuals.
6420 OCM is On Chip Memory, which I believe the 405GP has 4K. It
6421 is another option for the system designer to use as an
6422 initial stack/RAM area prior to SDRAM being available. Either
6423 option should work for you. Using CS 4 should be fine if your
6424 board designers haven't used it for something that would
6425 cause you grief during the initial boot! It is frequently not
6428 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
6429 with your processor/board/system design. The default value
6430 you will find in any recent u-boot distribution in
6431 walnut.h should work for you. I'd set it to a value larger
6432 than your SDRAM module. If you have a 64MB SDRAM module, set
6433 it above 400_0000. Just make sure your board has no resources
6434 that are supposed to respond to that address! That code in
6435 start.S has been around a while and should work as is when
6436 you get the config right.
6441 It is essential to remember this, since it has some impact on the C
6442 code for the initialization procedures:
6444 * Initialized global data (data segment) is read-only. Do not attempt
6447 * Do not use any uninitialized global data (or implicitly initialized
6448 as zero data - BSS segment) at all - this is undefined, initiali-
6449 zation is performed later (when relocating to RAM).
6451 * Stack space is very limited. Avoid big data buffers or things like
6454 Having only the stack as writable memory limits means we cannot use
6455 normal global data to share information between the code. But it
6456 turned out that the implementation of U-Boot can be greatly
6457 simplified by making a global data structure (gd_t) available to all
6458 functions. We could pass a pointer to this data as argument to _all_
6459 functions, but this would bloat the code. Instead we use a feature of
6460 the GCC compiler (Global Register Variables) to share the data: we
6461 place a pointer (gd) to the global data into a register which we
6462 reserve for this purpose.
6464 When choosing a register for such a purpose we are restricted by the
6465 relevant (E)ABI specifications for the current architecture, and by
6466 GCC's implementation.
6468 For PowerPC, the following registers have specific use:
6470 R2: reserved for system use
6471 R3-R4: parameter passing and return values
6472 R5-R10: parameter passing
6473 R13: small data area pointer
6477 (U-Boot also uses R12 as internal GOT pointer. r12
6478 is a volatile register so r12 needs to be reset when
6479 going back and forth between asm and C)
6481 ==> U-Boot will use R2 to hold a pointer to the global data
6483 Note: on PPC, we could use a static initializer (since the
6484 address of the global data structure is known at compile time),
6485 but it turned out that reserving a register results in somewhat
6486 smaller code - although the code savings are not that big (on
6487 average for all boards 752 bytes for the whole U-Boot image,
6488 624 text + 127 data).
6490 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
6491 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
6493 ==> U-Boot will use P3 to hold a pointer to the global data
6495 On ARM, the following registers are used:
6497 R0: function argument word/integer result
6498 R1-R3: function argument word
6499 R9: platform specific
6500 R10: stack limit (used only if stack checking is enabled)
6501 R11: argument (frame) pointer
6502 R12: temporary workspace
6505 R15: program counter
6507 ==> U-Boot will use R9 to hold a pointer to the global data
6509 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
6511 On Nios II, the ABI is documented here:
6512 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
6514 ==> U-Boot will use gp to hold a pointer to the global data
6516 Note: on Nios II, we give "-G0" option to gcc and don't use gp
6517 to access small data sections, so gp is free.
6519 On NDS32, the following registers are used:
6521 R0-R1: argument/return
6523 R15: temporary register for assembler
6524 R16: trampoline register
6525 R28: frame pointer (FP)
6526 R29: global pointer (GP)
6527 R30: link register (LP)
6528 R31: stack pointer (SP)
6529 PC: program counter (PC)
6531 ==> U-Boot will use R10 to hold a pointer to the global data
6533 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
6534 or current versions of GCC may "optimize" the code too much.
6539 U-Boot runs in system state and uses physical addresses, i.e. the
6540 MMU is not used either for address mapping nor for memory protection.
6542 The available memory is mapped to fixed addresses using the memory
6543 controller. In this process, a contiguous block is formed for each
6544 memory type (Flash, SDRAM, SRAM), even when it consists of several
6545 physical memory banks.
6547 U-Boot is installed in the first 128 kB of the first Flash bank (on
6548 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
6549 booting and sizing and initializing DRAM, the code relocates itself
6550 to the upper end of DRAM. Immediately below the U-Boot code some
6551 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
6552 configuration setting]. Below that, a structure with global Board
6553 Info data is placed, followed by the stack (growing downward).
6555 Additionally, some exception handler code is copied to the low 8 kB
6556 of DRAM (0x00000000 ... 0x00001FFF).
6558 So a typical memory configuration with 16 MB of DRAM could look like
6561 0x0000 0000 Exception Vector code
6564 0x0000 2000 Free for Application Use
6570 0x00FB FF20 Monitor Stack (Growing downward)
6571 0x00FB FFAC Board Info Data and permanent copy of global data
6572 0x00FC 0000 Malloc Arena
6575 0x00FE 0000 RAM Copy of Monitor Code
6576 ... eventually: LCD or video framebuffer
6577 ... eventually: pRAM (Protected RAM - unchanged by reset)
6578 0x00FF FFFF [End of RAM]
6581 System Initialization:
6582 ----------------------
6584 In the reset configuration, U-Boot starts at the reset entry point
6585 (on most PowerPC systems at address 0x00000100). Because of the reset
6586 configuration for CS0# this is a mirror of the on board Flash memory.
6587 To be able to re-map memory U-Boot then jumps to its link address.
6588 To be able to implement the initialization code in C, a (small!)
6589 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6590 which provide such a feature like MPC8xx or MPC8260), or in a locked
6591 part of the data cache. After that, U-Boot initializes the CPU core,
6592 the caches and the SIU.
6594 Next, all (potentially) available memory banks are mapped using a
6595 preliminary mapping. For example, we put them on 512 MB boundaries
6596 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6597 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6598 programmed for SDRAM access. Using the temporary configuration, a
6599 simple memory test is run that determines the size of the SDRAM
6602 When there is more than one SDRAM bank, and the banks are of
6603 different size, the largest is mapped first. For equal size, the first
6604 bank (CS2#) is mapped first. The first mapping is always for address
6605 0x00000000, with any additional banks following immediately to create
6606 contiguous memory starting from 0.
6608 Then, the monitor installs itself at the upper end of the SDRAM area
6609 and allocates memory for use by malloc() and for the global Board
6610 Info data; also, the exception vector code is copied to the low RAM
6611 pages, and the final stack is set up.
6613 Only after this relocation will you have a "normal" C environment;
6614 until that you are restricted in several ways, mostly because you are
6615 running from ROM, and because the code will have to be relocated to a
6619 U-Boot Porting Guide:
6620 ----------------------
6622 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6626 int main(int argc, char *argv[])
6628 sighandler_t no_more_time;
6630 signal(SIGALRM, no_more_time);
6631 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6633 if (available_money > available_manpower) {
6634 Pay consultant to port U-Boot;
6638 Download latest U-Boot source;
6640 Subscribe to u-boot mailing list;
6643 email("Hi, I am new to U-Boot, how do I get started?");
6646 Read the README file in the top level directory;
6647 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6648 Read applicable doc/*.README;
6649 Read the source, Luke;
6650 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6653 if (available_money > toLocalCurrency ($2500))
6656 Add a lot of aggravation and time;
6658 if (a similar board exists) { /* hopefully... */
6659 cp -a board/<similar> board/<myboard>
6660 cp include/configs/<similar>.h include/configs/<myboard>.h
6662 Create your own board support subdirectory;
6663 Create your own board include/configs/<myboard>.h file;
6665 Edit new board/<myboard> files
6666 Edit new include/configs/<myboard>.h
6671 Add / modify source code;
6675 email("Hi, I am having problems...");
6677 Send patch file to the U-Boot email list;
6678 if (reasonable critiques)
6679 Incorporate improvements from email list code review;
6681 Defend code as written;
6687 void no_more_time (int sig)
6696 All contributions to U-Boot should conform to the Linux kernel
6697 coding style; see the file "Documentation/CodingStyle" and the script
6698 "scripts/Lindent" in your Linux kernel source directory.
6700 Source files originating from a different project (for example the
6701 MTD subsystem) are generally exempt from these guidelines and are not
6702 reformatted to ease subsequent migration to newer versions of those
6705 Please note that U-Boot is implemented in C (and to some small parts in
6706 Assembler); no C++ is used, so please do not use C++ style comments (//)
6709 Please also stick to the following formatting rules:
6710 - remove any trailing white space
6711 - use TAB characters for indentation and vertical alignment, not spaces
6712 - make sure NOT to use DOS '\r\n' line feeds
6713 - do not add more than 2 consecutive empty lines to source files
6714 - do not add trailing empty lines to source files
6716 Submissions which do not conform to the standards may be returned
6717 with a request to reformat the changes.
6723 Since the number of patches for U-Boot is growing, we need to
6724 establish some rules. Submissions which do not conform to these rules
6725 may be rejected, even when they contain important and valuable stuff.
6727 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6729 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6730 see http://lists.denx.de/mailman/listinfo/u-boot
6732 When you send a patch, please include the following information with
6735 * For bug fixes: a description of the bug and how your patch fixes
6736 this bug. Please try to include a way of demonstrating that the
6737 patch actually fixes something.
6739 * For new features: a description of the feature and your
6742 * A CHANGELOG entry as plaintext (separate from the patch)
6744 * For major contributions, your entry to the CREDITS file
6746 * When you add support for a new board, don't forget to add a
6747 maintainer e-mail address to the boards.cfg file, too.
6749 * If your patch adds new configuration options, don't forget to
6750 document these in the README file.
6752 * The patch itself. If you are using git (which is *strongly*
6753 recommended) you can easily generate the patch using the
6754 "git format-patch". If you then use "git send-email" to send it to
6755 the U-Boot mailing list, you will avoid most of the common problems
6756 with some other mail clients.
6758 If you cannot use git, use "diff -purN OLD NEW". If your version of
6759 diff does not support these options, then get the latest version of
6762 The current directory when running this command shall be the parent
6763 directory of the U-Boot source tree (i. e. please make sure that
6764 your patch includes sufficient directory information for the
6767 We prefer patches as plain text. MIME attachments are discouraged,
6768 and compressed attachments must not be used.
6770 * If one logical set of modifications affects or creates several
6771 files, all these changes shall be submitted in a SINGLE patch file.
6773 * Changesets that contain different, unrelated modifications shall be
6774 submitted as SEPARATE patches, one patch per changeset.
6779 * Before sending the patch, run the MAKEALL script on your patched
6780 source tree and make sure that no errors or warnings are reported
6781 for any of the boards.
6783 * Keep your modifications to the necessary minimum: A patch
6784 containing several unrelated changes or arbitrary reformats will be
6785 returned with a request to re-formatting / split it.
6787 * If you modify existing code, make sure that your new code does not
6788 add to the memory footprint of the code ;-) Small is beautiful!
6789 When adding new features, these should compile conditionally only
6790 (using #ifdef), and the resulting code with the new feature
6791 disabled must not need more memory than the old code without your
6794 * Remember that there is a size limit of 100 kB per message on the
6795 u-boot mailing list. Bigger patches will be moderated. If they are
6796 reasonable and not too big, they will be acknowledged. But patches
6797 bigger than the size limit should be avoided.
projects / karo-tx-uboot.git / blob