This patch refactors RAMTOP MTRR type selection to address a critical
NEM logic bug on SoCs with non-power-of-two cache sets. This bug can
cause runtime hangs when Write Back (WB) caching is enabled.
Workaround: Force MTRR type to WC (Write Combining) on affected SoCs
when the cache set count is not a power of two.
BUG=b:306677879
BRANCH=firmware-rex-15709.B
TEST=Verified boot on google/ovis and google/rex (including Ovis with
non-power-of-two cache configuration).
Change-Id: Ia9a8f0d37d581b05c19ea7f9b1a07933caa956d4
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81269
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
9355f318fa