fdt: Allow non-FDT kernels to boot when CONFIG_OF_LIBFDT is defined

[karo-tx-uboot.git] / README

diff --git a/README b/README
index c3a9dfc4f0b3851580818217703882dc30e7f0c1..bfefa21b3bfd568bee43322e6210ff39dc151257 100644 (file)
--- a/README
+++ b/README
@@ -623,6 +623,120 @@ The following options need to be configured:
                exists, unlike the similar options in the Linux kernel. Do not
                set these options unless they apply!
 
                exists, unlike the similar options in the Linux kernel. Do not
                set these options unless they apply!
 

+- Driver Model
+               Driver model is a new framework for devices in U-Boot
+               introduced in early 2014. U-Boot is being progressively
+               moved over to this. It offers a consistent device structure,
+               supports grouping devices into classes and has built-in
+               handling of platform data and device tree.
+
+               To enable transition to driver model in a relatively
+               painful fashion, each subsystem can be independently
+               switched between the legacy/ad-hoc approach and the new
+               driver model using the options below. Also, many uclass
+               interfaces include compatibility features which may be
+               removed once the conversion of that subsystem is complete.
+               As a result, the API provided by the subsystem may in fact
+               not change with driver model.
+
+               See doc/driver-model/README.txt for more information.
+
+               CONFIG_DM
+
+               Enable driver model. This brings in the core support,
+               including scanning of platform data on start-up. If
+               CONFIG_OF_CONTROL is enabled, the device tree will be
+               scanned also when available.
+
+               CONFIG_CMD_DM
+
+               Enable driver model test commands. These allow you to print
+               out the driver model tree and the uclasses.
+
+               CONFIG_DM_DEMO
+
+               Enable some demo devices and the 'demo' command. These are
+               really only useful for playing around while trying to
+               understand driver model in sandbox.
+
+               CONFIG_SPL_DM
+
+               Enable driver model in SPL. You will need to provide a
+               suitable malloc() implementation. If you are not using the
+               full malloc() enabled by CONFIG_SYS_SPL_MALLOC_START,
+               consider using CONFIG_SYS_MALLOC_SIMPLE. In that case you
+               must provide CONFIG_SYS_MALLOC_F_LEN to set the size.
+               In most cases driver model will only allocate a few uclasses
+               and devices in SPL, so 1KB should be enable. See
+               CONFIG_SYS_MALLOC_F_LEN for more details on how to enable
+               it.
+
+               CONFIG_DM_SERIAL
+
+               Enable driver model for serial. This replaces
+               drivers/serial/serial.c with the serial uclass, which
+               implements serial_putc() etc. The uclass interface is
+               defined in include/serial.h.
+
+               CONFIG_DM_GPIO
+
+               Enable driver model for GPIO access. The standard GPIO
+               interface (gpio_get_value(), etc.) is then implemented by
+               the GPIO uclass. Drivers provide methods to query the
+               particular GPIOs that they provide. The uclass interface
+               is defined in include/asm-generic/gpio.h.
+
+               CONFIG_DM_SPI
+
+               Enable driver model for SPI. The SPI slave interface
+               (spi_setup_slave(), spi_xfer(), etc.) is then implemented by
+               the SPI uclass. Drivers provide methods to access the SPI
+               buses that they control. The uclass interface is defined in
+               include/spi.h. The existing spi_slave structure is attached
+               as 'parent data' to every slave on each bus. Slaves
+               typically use driver-private data instead of extending the
+               spi_slave structure.
+
+               CONFIG_DM_SPI_FLASH
+
+               Enable driver model for SPI flash. This SPI flash interface
+               (spi_flash_probe(), spi_flash_write(), etc.) is then
+               implemented by the SPI flash uclass. There is one standard
+               SPI flash driver which knows how to probe most chips
+               supported by U-Boot. The uclass interface is defined in
+               include/spi_flash.h, but is currently fully compatible
+               with the old interface to avoid confusion and duplication
+               during the transition parent. SPI and SPI flash must be
+               enabled together (it is not possible to use driver model
+               for one and not the other).
+
+               CONFIG_DM_CROS_EC
+
+               Enable driver model for the Chrome OS EC interface. This
+               allows the cros_ec SPI driver to operate with CONFIG_DM_SPI
+               but otherwise makes few changes. Since cros_ec also supports
+               I2C and LPC (which don't support driver model yet), a full
+               conversion is not yet possible.
+
+
+               ** Code size options: The following options are enabled by
+               default except in SPL. Enable them explicitly to get these
+               features in SPL.
+
+               CONFIG_DM_WARN
+
+               Enable the dm_warn() function. This can use up quite a bit
+               of space for its strings.
+
+               CONFIG_DM_STDIO
+
+               Enable registering a serial device with the stdio library.
+
+               CONFIG_DM_DEVICE_REMOVE
+
+               Enable removing of devices.
+
+

 - Linux Kernel Interface:
                CONFIG_CLOCKS_IN_MHZ
 
 - Linux Kernel Interface:
                CONFIG_CLOCKS_IN_MHZ
 


@@ -669,6 +783,13 @@ The following options need to be configured:
                Board code has addition modification that it wants to make
                to the flat device tree before handing it off to the kernel
 
                Board code has addition modification that it wants to make
                to the flat device tree before handing it off to the kernel
 

+               CONFIG_OF_SYSTEM_SETUP
+
+               Other code has addition modification that it wants to make
+               to the flat device tree before handing it off to the kernel.
+               This causes ft_system_setup() to be called before booting
+               the kernel.
+

                CONFIG_OF_BOOT_CPU
 
                This define fills in the correct boot CPU in the boot
                CONFIG_OF_BOOT_CPU
 
                This define fills in the correct boot CPU in the boot


@@ -989,6 +1110,7 @@ The following options need to be configured:
                CONFIG_CMD_EXT4         * ext4 command support
                CONFIG_CMD_FS_GENERIC   * filesystem commands (e.g. load, ls)
                                          that work for multiple fs types
                CONFIG_CMD_EXT4         * ext4 command support
                CONFIG_CMD_FS_GENERIC   * filesystem commands (e.g. load, ls)
                                          that work for multiple fs types

+               CONFIG_CMD_FS_UUID      * Look up a filesystem UUID

                CONFIG_CMD_SAVEENV        saveenv
                CONFIG_CMD_FDC          * Floppy Disk Support
                CONFIG_CMD_FAT          * FAT command support
                CONFIG_CMD_SAVEENV        saveenv
                CONFIG_CMD_FDC          * Floppy Disk Support
                CONFIG_CMD_FAT          * FAT command support


@@ -2834,18 +2956,6 @@ CBFS (Coreboot Filesystem) support
 
                Enable auto completion of commands using TAB.
 
 
                Enable auto completion of commands using TAB.
 

-               CONFIG_SYS_HUSH_PARSER
-
-               Define this variable to enable the "hush" shell (from
-               Busybox) as command line interpreter, thus enabling
-               powerful command line syntax like
-               if...then...else...fi conditionals or `&&' and '||'
-               constructs ("shell scripts").
-
-               If undefined, you get the old, much simpler behaviour
-               with a somewhat smaller memory footprint.
-
-

                CONFIG_SYS_PROMPT_HUSH_PS2
 
                This defines the secondary prompt string, which is
                CONFIG_SYS_PROMPT_HUSH_PS2
 
                This defines the secondary prompt string, which is


@@ -3407,7 +3517,7 @@ FIT uImage format:
                to 128 or 256, although it does not have to be power of 2).
 
                default: 4096
                to 128 or 256, although it does not have to be power of 2).
 
                default: 4096

-               
+

                CONFIG_MTD_UBI_BEB_LIMIT
                This option specifies the maximum bad physical eraseblocks UBI
                expects on the MTD device (per 1024 eraseblocks). If the
                CONFIG_MTD_UBI_BEB_LIMIT
                This option specifies the maximum bad physical eraseblocks UBI
                expects on the MTD device (per 1024 eraseblocks). If the


@@ -3547,10 +3657,13 @@ FIT uImage format:
 
                CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
                CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
 
                CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
                CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,

-               CONFIG_SYS_MMC_SD_FS_BOOT_PARTITION
-               Address, size and partition on the MMC to load U-Boot from
+               Address and partition on the MMC to load U-Boot from

                when the MMC is being used in raw mode.
 
                when the MMC is being used in raw mode.
 

+               CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
+               Partition on the MMC to load U-Boot from when the MMC is being
+               used in raw mode
+

                CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
                Sector to load kernel uImage from when MMC is being
                used in raw mode (for Falcon mode)
                CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
                Sector to load kernel uImage from when MMC is being
                used in raw mode (for Falcon mode)


@@ -3561,6 +3674,10 @@ FIT uImage format:
                parameters from when MMC is being used in raw mode
                (for falcon mode)
 
                parameters from when MMC is being used in raw mode
                (for falcon mode)
 

+               CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
+               Partition on the MMC to load U-Boot from when the MMC is being
+               used in fs mode
+

                CONFIG_SPL_FAT_SUPPORT
                Support for fs/fat/libfat.o in SPL binary
 
                CONFIG_SPL_FAT_SUPPORT
                Support for fs/fat/libfat.o in SPL binary
 


@@ -3605,6 +3722,10 @@ FIT uImage format:
                Support for the MTD subsystem within SPL.  Useful for
                environment on NAND support within SPL.
 
                Support for the MTD subsystem within SPL.  Useful for
                environment on NAND support within SPL.
 

+               CONFIG_SPL_NAND_RAW_ONLY
+               Support to boot only raw u-boot.bin images. Use this only
+               if you need to save space.
+

                CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
                Set for the SPL on PPC mpc8xxx targets, support for
                drivers/ddr/fsl/libddr.o in SPL binary.
                CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
                Set for the SPL on PPC mpc8xxx targets, support for
                drivers/ddr/fsl/libddr.o in SPL binary.


@@ -3877,6 +3998,11 @@ Configuration Settings:
                Pre-relocation malloc() is only supported on ARM and sandbox
                at present but is fairly easy to enable for other archs.
 
                Pre-relocation malloc() is only supported on ARM and sandbox
                at present but is fairly easy to enable for other archs.
 

+- CONFIG_SYS_MALLOC_SIMPLE
+               Provides a simple and small malloc() and calloc() for those
+               boards which do not use the full malloc in SPL (which is
+               enabled with CONFIG_SYS_SPL_MALLOC_START).
+

 - CONFIG_SYS_BOOTM_LEN:
                Normally compressed uImages are limited to an
                uncompressed size of 8 MBytes. If this is not enough,
 - CONFIG_SYS_BOOTM_LEN:
                Normally compressed uImages are limited to an
                uncompressed size of 8 MBytes. If this is not enough,