x86: Add a 64-bit 'coreboot64' build

Coreboot is a first-stage bootloader mostly used on x86 devices as an
alternative to UEFI. Coreboot runs in 32-bit mode.

U-Boot currently supports booting from coreboot as a second-stage
bootloader, also in 32-bit mode. However it is useful to be able to run
U-Boot in 64-bit mode. To do this we can have a 32-bit SPL which switches
over the CPU and jumps to a 64-bit U-Boot proper.

Add a new 'coreboot64' board for running 64-bit U-Boot from coreboot. This
uses binman to create an image with a 32-bit SPL and a 64-bit U-Boot.

This allows running 64-bit EFI images on x86, for example, without needing
a native U-Boot port for a board.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>

3 files changed, 65 insertions, 0 deletions

diff --git a/board/coreboot/coreboot/MAINTAINERS b/board/coreboot/coreboot/MAINTAINERS
index 188906b0803..a05673bb0be 100644
--- a/board/coreboot/coreboot/MAINTAINERS
+++ b/board/coreboot/coreboot/MAINTAINERS
@@ -4,3 +4,10 @@ S:	Maintained
 F:	board/coreboot/coreboot/
 F:	include/configs/chromebook_link.h
 F:	configs/coreboot_defconfig
+
+COREBOOT64 BOARD
+M:	Simon Glass <sjg@chromium.org>
+S:	Maintained
+F:	board/coreboot/coreboot/
+F:	include/configs/chromebook_link.h
+F:	configs/coreboot64_defconfig
diff --git a/configs/coreboot64_defconfig b/configs/coreboot64_defconfig
new file mode 100644
index 00000000000..80353b8eb36
--- /dev/null
+++ b/configs/coreboot64_defconfig
@@ -0,0 +1,48 @@
+CONFIG_X86=y
+CONFIG_SYS_TEXT_BASE=0x1120000
+CONFIG_ENV_SIZE=0x1000
+CONFIG_NR_DRAM_BANKS=8
+CONFIG_PRE_CON_BUF_ADDR=0x100000
+CONFIG_X86_RUN_64BIT=y
+CONFIG_VENDOR_COREBOOT=y
+CONFIG_TARGET_COREBOOT=y
+CONFIG_SPL_TEXT_BASE=0x1110000
+CONFIG_FIT=y
+CONFIG_FIT_SIGNATURE=y
+CONFIG_SHOW_BOOT_PROGRESS=y
+CONFIG_USE_BOOTARGS=y
+CONFIG_BOOTARGS="root=/dev/sdb3 init=/sbin/init rootwait ro"
+CONFIG_PRE_CONSOLE_BUFFER=y
+CONFIG_SYS_CONSOLE_INFO_QUIET=y
+CONFIG_DISPLAY_BOARDINFO_LATE=y
+CONFIG_LAST_STAGE_INIT=y
+CONFIG_HUSH_PARSER=y
+CONFIG_CMD_IDE=y
+CONFIG_CMD_MMC=y
+CONFIG_CMD_PART=y
+CONFIG_CMD_USB=y
+# CONFIG_CMD_SETEXPR is not set
+CONFIG_CMD_DHCP=y
+# CONFIG_CMD_NFS is not set
+CONFIG_CMD_PING=y
+CONFIG_CMD_TIME=y
+CONFIG_CMD_SOUND=y
+CONFIG_CMD_EXT2=y
+CONFIG_CMD_EXT4=y
+CONFIG_CMD_EXT4_WRITE=y
+CONFIG_CMD_FAT=y
+CONFIG_CMD_FS_GENERIC=y
+CONFIG_MAC_PARTITION=y
+# CONFIG_SPL_MAC_PARTITION is not set
+# CONFIG_SPL_DOS_PARTITION is not set
+CONFIG_ISO_PARTITION=y
+CONFIG_EFI_PARTITION=y
+# CONFIG_SPL_EFI_PARTITION is not set
+CONFIG_DEFAULT_DEVICE_TREE="coreboot"
+CONFIG_SYS_RELOC_GD_ENV_ADDR=y
+CONFIG_REGMAP=y
+CONFIG_SYSCON=y
+# CONFIG_PCI_PNP is not set
+CONFIG_SOUND=y
+CONFIG_SOUND_I8254=y
+CONFIG_CONSOLE_SCROLL_LINES=5
diff --git a/doc/board/coreboot/coreboot.rst b/doc/board/coreboot/coreboot.rst
index fd974229eb4..9c44c025a48 100644
--- a/doc/board/coreboot/coreboot.rst
+++ b/doc/board/coreboot/coreboot.rst
@@ -40,3 +40,13 @@ To enable video you must enable these options in coreboot:
 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.
+
+64-bit U-Boot
+-------------
+
+In addition to the 32-bit 'coreboot' build there is a 'coreboot64' build. This
+produces an image which can be booted from coreboot (32-bit). Internally it
+works by using a 32-bit SPL binary to switch to 64-bit for running U-Boot. It
+can be useful for running UEFI applications, for example.
+
+This has only been lightly tested.