X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=doc%2FREADME.x86;h=ef13fb45f4ce953d2188db040287a20521f4e2c1;hb=f0db144d459e33ed77a6aaaa06cb71e041a46877;hp=5fab04491f3b04a43a8a1d37e476e5119a1f2e54;hpb=b4a0b4006fe4d6542899abf402c0569b11aa18e2;p=karo-tx-uboot.git diff --git a/doc/README.x86 b/doc/README.x86 index 5fab04491f..ef13fb45f4 100644 --- a/doc/README.x86 +++ b/doc/README.x86 @@ -18,11 +18,11 @@ U-Boot supports running as a coreboot [1] payload on x86. So far only Link on other x86 boards since coreboot deals with most of the low-level details. U-Boot also supports booting directly from x86 reset vector without coreboot, -aka raw support or bare support. Currently Link and Intel Crown Bay board -support running U-Boot 'bare metal'. +aka raw support or bare support. Currently Link, Intel Crown Bay, Intel +Minnowboard Max and Intel Galileo support running U-Boot 'bare metal'. -As for loading OS, U-Boot supports directly booting a 32-bit or 64-bit Linux -kernel as part of a FIT image. It also supports a compressed zImage. +As for loading an OS, U-Boot supports directly booting a 32-bit or 64-bit +Linux kernel as part of a FIT image. It also supports a compressed zImage. Build Instructions ------------------ @@ -32,13 +32,30 @@ on other architectures, like below: $ make coreboot-x86_defconfig $ make all -Building ROM version of U-Boot (hereafter referred to as u-boot.rom) is a +Note this default configuration will build a U-Boot payload for the Link board. +To build a coreboot payload against another board, you can change the build +configuration during the 'make menuconfig' process. + +x86 architecture ---> + ... + (chromebook_link) Board configuration file + (chromebook_link) Board Device Tree Source (dts) file + (0x19200000) Board specific Cache-As-RAM (CAR) address + (0x4000) Board specific Cache-As-RAM (CAR) size + +Change the 'Board configuration file' and 'Board Device Tree Source (dts) file' +to point to a new board. You can also change the Cache-As-RAM (CAR) related +settings here if the default values do not fit your new board. + +Building a ROM version of U-Boot (hereafter referred to as u-boot.rom) is a little bit tricky, as generally it requires several binary blobs which are not shipped in the U-Boot source tree. Due to this reason, the u-boot.rom build is not turned on by default in the U-Boot source tree. Firstly, you need turn it -on by uncommenting the following line in the main U-Boot Makefile: +on by enabling the ROM build: + +$ export BUILD_ROM=y -# ALL-$(CONFIG_X86_RESET_VECTOR) += u-boot.rom +This tells the Makefile to build u-boot.rom as a target. Link-specific instructions: @@ -58,7 +75,7 @@ Find the following files: * ./mainboard/google/link/descriptor.bin * ./mainboard/google/link/me.bin -* ./northbridge/intel/sandybridge/systemagent-ivybridge.bin +* ./northbridge/intel/sandybridge/systemagent-r6.bin The 3rd one should be renamed to mrc.bin. As for the video ROM, you can get it here [2]. @@ -88,14 +105,112 @@ in this FSP package too. Rename the first one to fsp.bin and second one to cmc.bin and put them in the board directory. -Now you can build U-Boot and obtaim u-boot.rom +Note the FSP release version 001 has a bug which could cause random endless +loop during the FspInit call. This bug was published by Intel although Intel +did not describe any details. We need manually apply the patch to the FSP +binary using any hex editor (eg: bvi). Go to the offset 0x1fcd8 of the FSP +binary, change the following five bytes values from orginally E8 42 FF FF FF +to B8 00 80 0B 00. + +Now you can build U-Boot and obtain u-boot.rom $ make crownbay_defconfig $ make all +Intel Minnowboard Max instructions: + +This uses as FSP as with Crown Bay, except it is for the Atom E3800 series. +Download this and get the .fd file (BAYTRAIL_FSP_GOLD_003_16-SEP-2014.fd at +the time of writing). Put it in the board directory: +board/intel/minnowmax/fsp.bin + +Obtain the VGA RAM (Vga.dat at the time of writing) and put it into the same +directory: board/intel/minnowmax/vga.bin + +You still need two more binary blobs. The first comes from the original +firmware image available from: + +http://firmware.intel.com/sites/default/files/2014-WW42.4-MinnowBoardMax.73-64-bit.bin_Release.zip + +Unzip it: + + $ unzip 2014-WW42.4-MinnowBoardMax.73-64-bit.bin_Release.zip + +Use ifdtool in the U-Boot tools directory to extract the images from that +file, for example: + + $ ./tools/ifdtool -x MNW2MAX1.X64.0073.R02.1409160934.bin + +This will provide the descriptor file - copy this into the correct place: + + $ cp flashregion_0_flashdescriptor.bin board/intel/minnowmax/descriptor.bin + +Then do the same with the sample SPI image provided in the FSP (SPI.bin at +the time of writing) to obtain the last image. Note that this will also +produce a flash descriptor file, but it does not seem to work, probably +because it is not designed for the Minnowmax. That is why you need to get +the flash descriptor from the original firmware as above. + + $ ./tools/ifdtool -x BayleyBay/SPI.bin + $ cp flashregion_2_intel_me.bin board/intel/minnowmax/me.bin + +Now you can build U-Boot and obtain u-boot.rom + +$ make minnowmax_defconfig +$ make all + +Intel Galileo instructions: + +Only one binary blob is needed for Remote Management Unit (RMU) within Intel +Quark SoC. Not like FSP, U-Boot does not call into the binary. The binary is +needed by the Quark SoC itself. + +You can get the binary blob from Quark Board Support Package from Intel website: + +* ./QuarkSocPkg/QuarkNorthCluster/Binary/QuarkMicrocode/RMU.bin + +Rename the file and put it to the board directory by: + + $ cp RMU.bin board/intel/galileo/rmu.bin + +Now you can build U-Boot and obtain u-boot.rom + +$ make galileo_defconfig +$ make all + +Test with coreboot +------------------ +For testing U-Boot as the coreboot payload, there are things that need be paid +attention to. coreboot supports loading an ELF executable and a 32-bit plain +binary, as well as other supported payloads. With the default configuration, +U-Boot is set up to use a separate Device Tree Blob (dtb). As of today, the +generated u-boot-dtb.bin needs to be packaged by the cbfstool utility (a tool +provided by coreboot) manually as coreboot's 'make menuconfig' does not provide +this capability yet. The command is as follows: + +# in the coreboot root directory +$ ./build/util/cbfstool/cbfstool build/coreboot.rom add-flat-binary \ + -f u-boot-dtb.bin -n fallback/payload -c lzma -l 0x1110000 -e 0x1110015 + +Make sure 0x1110000 matches CONFIG_SYS_TEXT_BASE and 0x1110015 matches the +symbol address of _start (in arch/x86/cpu/start.S). + +If you want to use ELF as the coreboot payload, change U-Boot configuration to +use CONFIG_OF_EMBED instead of CONFIG_OF_SEPARATE. + +To enable video you must enable these options in coreboot: + + - Set framebuffer graphics resolution (1280x1024 32k-color (1:5:5)) + - Keep VESA framebuffer + +At present it seems that for Minnowboard Max, coreboot does not pass through +the video information correctly (it always says the resolution is 0x0). This +works correctly for link though. + + CPU Microcode ------------- -Modern CPU usually requires a special bit stream called microcode [5] to be +Modern CPUs usually require a special bit stream called microcode [5] to be loaded on the processor after power up in order to function properly. U-Boot has already integrated these as hex dumps in the source tree. @@ -106,13 +221,92 @@ x86 has been converted to use driver model for serial and GPIO. Device Tree ----------- x86 uses device tree to configure the board thus requires CONFIG_OF_CONTROL to -be turned on. Not every device on the board is configured via devie tree, but +be turned on. Not every device on the board is configured via device tree, but more and more devices will be added as time goes by. Check out the directory arch/x86/dts/ for these device tree source files. +Useful Commands +--------------- + +In keeping with the U-Boot philosophy of providing functions to check and +adjust internal settings, there are several x86-specific commands that may be +useful: + +hob - Display information about Firmware Support Package (FSP) Hand-off + Block. This is only available on platforms which use FSP, mostly + Atom. +iod - Display I/O memory +iow - Write I/O memory +mtrr - List and set the Memory Type Range Registers (MTRR). These are used to + tell the CPU whether memory is cacheable and if so the cache write + mode to use. U-Boot sets up some reasonable values but you can + adjust then with this command. + +Development Flow +---------------- +These notes are for those who want to port U-Boot to a new x86 platform. + +Since x86 CPUs boot from SPI flash, a SPI flash emulator is a good investment. +The Dediprog em100 can be used on Linux. The em100 tool is available here: + + http://review.coreboot.org/p/em100.git + +On Minnowboard Max the following command line can be used: + + sudo em100 -s -p LOW -d u-boot.rom -c W25Q64DW -r + +A suitable clip for connecting over the SPI flash chip is here: + + http://www.dediprog.com/pd/programmer-accessories/EM-TC-8 + +This allows you to override the SPI flash contents for development purposes. +Typically you can write to the em100 in around 1200ms, considerably faster +than programming the real flash device each time. The only important +limitation of the em100 is that it only supports SPI bus speeds up to 20MHz. +This means that images must be set to boot with that speed. This is an +Intel-specific feature - e.g. tools/ifttool has an option to set the SPI +speed in the SPI descriptor region. + +If your chip/board uses an Intel Firmware Support Package (FSP) it is fairly +easy to fit it in. You can follow the Minnowboard Max implementation, for +example. Hopefully you will just need to create new files similar to those +in arch/x86/cpu/baytrail which provide Bay Trail support. + +If you are not using an FSP you have more freedom and more responsibility. +The ivybridge support works this way, although it still uses a ROM for +graphics and still has binary blobs containing Intel code. You should aim to +support all important peripherals on your platform including video and storage. +Use the device tree for configuration where possible. + +For the microcode you can create a suitable device tree file using the +microcode tool: + + ./tools/microcode-tool -d microcode.dat create + +or if you only have header files and not the full Intel microcode.dat database: + + ./tools/microcode-tool -H BAY_TRAIL_FSP_KIT/Microcode/M0130673322.h \ + -H BAY_TRAIL_FSP_KIT/Microcode/M0130679901.h \ + create all + +These are written to arch/x86/dts/microcode/ by default. + +Note that it is possible to just add the micrcode for your CPU if you know its +model. U-Boot prints this information when it starts + + CPU: x86_64, vendor Intel, device 30673h + +so here we can use the M0130673322 file. + +If you platform can display POST codes on two little 7-segment displays on +the board, then you can use post_code() calls from C or assembler to monitor +boot progress. This can be good for debugging. + +If not, you can try to get serial working as early as possible. The early +debug serial port may be useful here. See setup_early_uart() for an example. + TODO List --------- -- MTRR support (for performance) - Audio - Chrome OS verified boot - SMI and ACPI support, to provide platform info and facilities to Linux