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Diffstat (limited to 'doc/board/google/chromebook_samus.rst')
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diff --git a/doc/board/google/chromebook_samus.rst b/doc/board/google/chromebook_samus.rst new file mode 100644 index 0000000000..eab1128e4f --- /dev/null +++ b/doc/board/google/chromebook_samus.rst @@ -0,0 +1,101 @@ +.. SPDX-License-Identifier: GPL-2.0+ +.. sectionauthor:: Simon Glass <sjg@chromium.org> + +Chromebook Samus +================ + +First, you need the following binary blobs: + + * descriptor.bin - Intel flash descriptor + * me.bin - Intel Management Engine + * mrc.bin - Memory Reference Code, which sets up SDRAM + * refcode.elf - Additional Reference code + * vga.bin - video ROM, which sets up the display + +If you have a samus you can obtain them from your flash, for example, in +developer mode on the Chromebook (use Ctrl-Alt-F2 to obtain a terminal and +log in as 'root'):: + + cd /tmp + flashrom -w samus.bin + scp samus.bin username@ip_address:/path/to/somewhere + +If not see the coreboot tree where you can use:: + + bash crosfirmware.sh samus + +to get the image. There is also an 'extract_blobs.sh' scripts that you can use +on the 'coreboot-Google_Samus.*' file to short-circuit some of the below. + +Then 'ifdtool -x samus.bin' on your development machine will produce:: + + flashregion_0_flashdescriptor.bin + flashregion_1_bios.bin + flashregion_2_intel_me.bin + +Rename flashregion_0_flashdescriptor.bin to descriptor.bin +Rename flashregion_2_intel_me.bin to me.bin +You can ignore flashregion_1_bios.bin - it is not used. + +To get the rest, use 'cbfstool samus.bin print':: + + samus.bin: 8192 kB, bootblocksize 2864, romsize 8388608, offset 0x700000 + alignment: 64 bytes, architecture: x86 + +============================ ======== =========== ====== +Name Offset Type Size +============================ ======== =========== ====== +cmos_layout.bin 0x700000 cmos_layout 1164 +pci8086,0406.rom 0x7004c0 optionrom 65536 +spd.bin 0x710500 (unknown) 4096 +cpu_microcode_blob.bin 0x711540 microcode 70720 +fallback/romstage 0x722a00 stage 54210 +fallback/ramstage 0x72fe00 stage 96382 +config 0x7476c0 raw 6075 +fallback/vboot 0x748ec0 stage 15980 +fallback/refcode 0x74cd80 stage 75578 +fallback/payload 0x75f500 payload 62878 +u-boot.dtb 0x76eb00 (unknown) 5318 +(empty) 0x770000 null 196504 +mrc.bin 0x79ffc0 (unknown) 222876 +(empty) 0x7d66c0 null 167320 +============================ ======== =========== ====== + +You can extract what you need:: + + cbfstool samus.bin extract -n pci8086,0406.rom -f vga.bin + cbfstool samus.bin extract -n fallback/refcode -f refcode.rmod + cbfstool samus.bin extract -n mrc.bin -f mrc.bin + cbfstool samus.bin extract -n fallback/refcode -f refcode.bin -U + +Note that the -U flag is only supported by the latest cbfstool. It unpacks +and decompresses the stage to produce a coreboot rmodule. This is a simple +representation of an ELF file. You need the patch "Support decoding a stage +with compression". + +Put all 5 files into board/google/chromebook_samus. + +Now you can build U-Boot and obtain u-boot.rom:: + + $ make chromebook_samus_defconfig + $ make all + +If you are using em100, then this command will flash write -Boot:: + + em100 -s -d filename.rom -c W25Q64CV -r + +Flash map for samus / broadwell: + + :fffff800: SYS_X86_START16 + :ffff0000: RESET_SEG_START + :fffd8000: TPL_TEXT_BASE + :fffa0000: X86_MRC_ADDR + :fff90000: VGA_BIOS_ADDR + :ffed0000: SYS_TEXT_BASE + :ffea0000: X86_REFCODE_ADDR + :ffe70000: SPL_TEXT_BASE + :ffbf8000: CONFIG_ENV_OFFSET (environemnt offset) + :ffbe0000: rw-mrc-cache (Memory-reference-code cache) + :ffa00000: <spare> + :ff801000: intel-me (address set by descriptor.bin) + :ff800000: intel-descriptor |