U-Boot can be chainloaded from vendor firmware on ARM64 chromebooks from
a GPT partition (roughly the same as in doc/chromium/chainload.rst), but
an appropriate image header must be built-in to the U-Boot binary by
enabling LINUX_KERNEL_IMAGE_HEADER.
This header has a field for an image load offset from 2MiB alignment
which must also be customized through LNX_KRNL_IMG_TEXT_OFFSET_BASE.
Set it equal to SYS_TEXT_BASE by default for Rockchip boards, which
happens to make this offset zero and works fine on chromebook_kevin
both for chainloading and bare-metal use.
Signed-off-by: Alper Nebi Yasak <alpernebiya...@gmail.com>
---
Looks like ARM64 chromebooks also need POSITION_INDEPENDENT=y to
chainload that way, but I'm not enabling the configs here. I'm thinking
of selecting these from new configs that also enable binman definitions
for the kernel partition and legacy boot images.
arch/arm/mach-rockchip/Kconfig | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/arm/mach-rockchip/Kconfig b/arch/arm/mach-rockchip/Kconfig
index 92f35309e4a6..308dc09b0389 100644
--- a/arch/arm/mach-rockchip/Kconfig
+++ b/arch/arm/mach-rockchip/Kconfig
@@ -390,6 +390,9 @@ config ROCKCHIP_SPI_IMAGE
containing U-Boot. The image is built by binman. U-Boot sits near
the start of the image.
+config LNX_KRNL_IMG_TEXT_OFFSET_BASE
+ default SYS_TEXT_BASE
+
source "arch/arm/mach-rockchip/px30/Kconfig"
source "arch/arm/mach-rockchip/rk3036/Kconfig"
source "arch/arm/mach-rockchip/rk3128/Kconfig"
--
2.34.1
