tree bf45f43f69740640cd97be5787a15cc5bdcfd2c6
parent 0f910e7db903fe07698f01685b880065b2f6ca4e
author Reka Norman <rekanorman@google.com> 1696286821 +1100
committer Subrata Banik <subratabanik@google.com> 1704431543 +0000

util/ifdtool: Add support for disabling GPR0

On ChromeOS devices with updateable CSE firmware, the GPR0 (Global
Protected Range) register is used to ensure the CSE RO is write
protected even when the FLMSTR-based protection is temporarily disabled
by coreboot to allow updating the CSE RW. For more details see
Documentation/soc/intel/cse_fw_update/cse_fw_update.md

Therefore to allow modifying the CSE firmware from the CPU, the
descriptor must have both the FLMSTR-based protection disabled (which
can be done using ifdtool --unlock), and GPR0 disabled.

Add an ifdtool option for disabling GPR0. For now I've added support for
all platforms for which I have the SPI programming guide. Support for
more platforms can be added in the future if needed.

BUG=b:270275115
TEST=Run `ifdtool -p adl -g image.bin -O image-unlocked.bin` on a locked
craask image, check the GPR0 field is set to 0.

Change-Id: Iee13ce0b702b3c7a443501cb4fc282580869d03a
Signed-off-by: Reka Norman <rekanorman@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/79788
Reviewed-by: Subrata Banik <subratabanik@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>