At present U-Boot's x86 support requires Coreboot to run first, starting up the CPU and then setting up SDRAM and video among other tasks. U-Boot then runs as a payload. Notably U-Boot does not handle the ACPI fun on x86 where the kernel can call back into the 'BIOS' to perform certain tasks.
This Coreboot + U-Boot method is used for link (Chromebook Pixel) and it works fairly well.
However this does not remove the need for all x86-specific init in U-Boot. For each generation of chipset we need to adjust U-Boot to make it work, albeit sometimes not a lot. In any case this work has not been done so the x86 port risks being stranded.
There are also a few disadvantages to using two separate boot loaders. When Coreboot decides not set to up the video card, it is not possible for U-Boot to go back and do this.
Building an image which has both boot loaders in itis a little tricky, particularly with the binary blobs that are required.
After some experimentation prompted by a discussion at ELCE, it was found that while x86 is somewhat different to most of the other architectures that U-Boot supports, it actually fits the model fairly well. There is nothing magic about getting the platform running. Also it turns out that x86 likes running before relocation with no DRAM, using global_data, relocating and then starting up the full U-Boot, all within the same image (Coreboot splits this into three programs which run one after the other). Perhaps this is because U-Boot was conceived before the more modern SoCs with SRAM, FAT file system code in the ROM, etc.
This series contains a basic port of U-Boot to a bare x86 environment. It would be targeted at some generally available board, such as the Minnowmax, except that it doesn't seem to be generally available, at least for me. So while that remains a goal, for now the port targets link. It is already supported in U-Boot and the platform is well understood.
The following are implemented in this series: - ivybridge support with some peripherals enabled - SDRAM init using a binary blob (Memory Reference Code) - Use of Intel Management Engine via another binary blob - microcode update from device tree - ifttool for creating ROMs of the required format (u-boot.rom) - GPIO
Notably missing are: - PCI device support (USB, SATA) - Video support - MTRR setup (for performance) - Real time clock - Chrome OS EC - Documentation - Links to binary blobs
These will be addressed in a follow-up series. Things like ACPI and SMI will come later.
Unfortunately this series is quite long as it includes basic infrastructure needed on x86. But it is a solid step forward: with this series, link boots to a prompt.
This series is available at u-boot-x86/working
Simon Glass (39): Move early malloc() to before arch_cpu_init() fdt: Add a function to decode a variable-sized u32 array dm: serial: Move current serial port pointer to global_data dm: gpio: Add a function to read an ID from a list of GPIOs x86: Add ifdtool for working with Intel Flash Descriptor ROM images x86: config: Move common x86 configs to a common file x86: Add processor functions for cpuid and stack pointer x86: Remove REALMODE_BASE which is no longer used x86: Remove board_init16() call which is not used x86: Remove unused early_board_init() call x86: Invalidate TLB as early as possible x86: Tidy up global descriptor table setup x86: Use the standard dram_init() function x86: Use the standard arch_cpu_init() function x86: Remove unnecessary find_fdt() function x86: Fix up some missing prototypes x86: Add chromebook_link board x86: Save the BIST value on reset x86: Build a .rom file which can be flashed to an x86 machine x86: Emit post codes in startup code x86: chromebook_link: Implement CAR support (cache as RAM) x86: Move Coreboot PCI into common cpu area x86: Refactor PCI to permit alternate init x86: ivybridge: Enable PCI in early init x86: pci: Allow configuration before relocation x86: ivybridge: Add early LPC init so that serial works x86: Tidy up coreboot header usage x86: Add clr/setbits functions x86: Add msr read/write functions that use a structure x86: ivybridge: Perform initial CPU setup x86: ivybridge: Check BIST value on boot x86: ivybridge: Perform Intel microcode update on boot RFC: x86: dts: Add microcode updates for ivybridge CPU x86: ivybridge: Add early init for PCH devices x86: ivybridge: Add support for early GPIO init x86: chromebook_link: Enable GPIO support x86: Make show_boot_progress() common x86: ivybridge: Add LAPIC support x86: ivybridge: Implement SDRAM init
Makefile | 32 +- arch/x86/Kconfig | 54 ++ arch/x86/config.mk | 1 - arch/x86/cpu/Makefile | 1 + arch/x86/cpu/coreboot/Makefile | 1 - arch/x86/cpu/coreboot/coreboot.c | 44 +- arch/x86/cpu/coreboot/ipchecksum.c | 2 +- arch/x86/cpu/coreboot/pci.c | 49 - arch/x86/cpu/coreboot/sdram.c | 15 +- arch/x86/cpu/coreboot/tables.c | 6 +- arch/x86/cpu/cpu.c | 60 +- arch/x86/cpu/interrupts.c | 2 +- arch/x86/cpu/ivybridge/Kconfig | 157 ++++ arch/x86/cpu/ivybridge/Makefile | 15 + arch/x86/cpu/ivybridge/car.S | 174 ++++ arch/x86/cpu/ivybridge/cpu.c | 356 +++++++ arch/x86/cpu/ivybridge/early_init.c | 145 +++ arch/x86/cpu/ivybridge/early_me.c | 191 ++++ arch/x86/cpu/ivybridge/lpc.c | 48 + arch/x86/cpu/ivybridge/me_status.c | 195 ++++ arch/x86/cpu/ivybridge/microcode_intel.c | 150 +++ arch/x86/cpu/ivybridge/report_platform.c | 98 ++ arch/x86/cpu/ivybridge/sdram.c | 571 +++++++++++ arch/x86/cpu/pci.c | 150 +++ arch/x86/cpu/start.S | 66 +- arch/x86/cpu/start16.S | 18 +- arch/x86/dts/Makefile | 1 + arch/x86/dts/chromebook_link.dts | 1 + arch/x86/dts/link.dts | 127 ++- arch/x86/dts/m12206a7_00000028.dtsi | 622 ++++++++++++ arch/x86/dts/m12306a9_00000017.dtsi | 750 +++++++++++++++ arch/x86/include/asm/arch-coreboot/gpio.h | 5 - arch/x86/include/asm/arch-ivybridge/gpio.h | 10 + arch/x86/include/asm/arch-ivybridge/me.h | 357 +++++++ arch/x86/include/asm/arch-ivybridge/microcode.h | 20 + arch/x86/include/asm/arch-ivybridge/model_206ax.h | 82 ++ arch/x86/include/asm/arch-ivybridge/pch.h | 356 +++++++ arch/x86/include/asm/arch-ivybridge/pei_data.h | 121 +++ arch/x86/include/asm/arch-ivybridge/sandybridge.h | 109 +++ arch/x86/include/asm/config.h | 1 + arch/x86/include/asm/global_data.h | 24 + arch/x86/include/asm/gpio.h | 142 ++- arch/x86/include/asm/init_helpers.h | 1 - arch/x86/include/asm/io.h | 49 + arch/x86/include/asm/lapic.h | 59 ++ arch/x86/include/asm/lapic_def.h | 101 ++ arch/x86/include/asm/msr.h | 19 + arch/x86/include/asm/mtrr.h | 121 +++ arch/x86/include/asm/pci.h | 13 + arch/x86/include/asm/post.h | 50 + arch/x86/include/asm/processor.h | 135 +++ arch/x86/include/asm/u-boot-x86.h | 19 +- arch/x86/lib/Makefile | 1 + arch/x86/lib/ramtest.c | 79 ++ board/chromebook-x86/coreboot/Makefile | 2 +- board/chromebook-x86/coreboot/coreboot_start.S | 13 - board/google/chromebook_link/Kconfig | 31 + board/google/chromebook_link/MAINTAINERS | 6 + board/google/chromebook_link/Makefile | 15 + board/google/chromebook_link/link.c | 124 +++ common/board_f.c | 14 +- configs/chromebook_link_defconfig | 10 + doc/device-tree-bindings/misc/intel-lpc.txt | 23 + drivers/gpio/gpio-uclass.c | 19 + drivers/gpio/intel_ich6_gpio.c | 79 +- drivers/serial/serial-uclass.c | 35 +- include/asm-generic/global_data.h | 1 + include/asm-generic/gpio.h | 11 +- include/configs/chromebook_link.h | 68 ++ include/configs/coreboot.h | 289 +----- include/configs/x86-common.h | 272 ++++++ include/fdtdec.h | 18 + lib/asm-offsets.c | 3 + lib/fdtdec.c | 22 + tools/Makefile | 2 + tools/ifdtool.c | 1039 +++++++++++++++++++++ tools/ifdtool.h | 88 ++ 77 files changed, 7690 insertions(+), 470 deletions(-) delete mode 100644 arch/x86/cpu/coreboot/pci.c create mode 100644 arch/x86/cpu/ivybridge/Kconfig create mode 100644 arch/x86/cpu/ivybridge/Makefile create mode 100644 arch/x86/cpu/ivybridge/car.S create mode 100644 arch/x86/cpu/ivybridge/cpu.c create mode 100644 arch/x86/cpu/ivybridge/early_init.c create mode 100644 arch/x86/cpu/ivybridge/early_me.c create mode 100644 arch/x86/cpu/ivybridge/lpc.c create mode 100644 arch/x86/cpu/ivybridge/me_status.c create mode 100644 arch/x86/cpu/ivybridge/microcode_intel.c create mode 100644 arch/x86/cpu/ivybridge/report_platform.c create mode 100644 arch/x86/cpu/ivybridge/sdram.c create mode 100644 arch/x86/cpu/pci.c create mode 120000 arch/x86/dts/chromebook_link.dts create mode 100644 arch/x86/dts/m12206a7_00000028.dtsi create mode 100644 arch/x86/dts/m12306a9_00000017.dtsi create mode 100644 arch/x86/include/asm/arch-ivybridge/gpio.h create mode 100644 arch/x86/include/asm/arch-ivybridge/me.h create mode 100644 arch/x86/include/asm/arch-ivybridge/microcode.h create mode 100644 arch/x86/include/asm/arch-ivybridge/model_206ax.h create mode 100644 arch/x86/include/asm/arch-ivybridge/pch.h create mode 100644 arch/x86/include/asm/arch-ivybridge/pei_data.h create mode 100644 arch/x86/include/asm/arch-ivybridge/sandybridge.h create mode 100644 arch/x86/include/asm/lapic.h create mode 100644 arch/x86/include/asm/lapic_def.h create mode 100644 arch/x86/include/asm/mtrr.h create mode 100644 arch/x86/include/asm/post.h create mode 100644 arch/x86/lib/ramtest.c delete mode 100644 board/chromebook-x86/coreboot/coreboot_start.S create mode 100644 board/google/chromebook_link/Kconfig create mode 100644 board/google/chromebook_link/MAINTAINERS create mode 100644 board/google/chromebook_link/Makefile create mode 100644 board/google/chromebook_link/link.c create mode 100644 configs/chromebook_link_defconfig create mode 100644 doc/device-tree-bindings/misc/intel-lpc.txt create mode 100644 include/configs/chromebook_link.h create mode 100644 include/configs/x86-common.h create mode 100644 tools/ifdtool.c create mode 100644 tools/ifdtool.h