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authorSimon Glass2020-05-01 07:36:10 -0600
committerBin Meng2020-05-04 15:28:28 +0800
commit538437ed39e01b7ecfa79669982fe7db51fb2e1b (patch)
tree50ff767d8d52438b551ae11641c9d42d4274ea36 /doc
parent8d99d5434b1c98c832f7a1aa0a0e0c9ab4c284a1 (diff)
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>
Diffstat (limited to 'doc')
-rw-r--r--doc/board/coreboot/coreboot.rst10
1 files changed, 10 insertions, 0 deletions
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.