tree 0a2880f81e615e400cdd3f6cfdb1a229e390411c
parent 6e303aa89b906dc12b0bbf6024a23de339634eb1
author Sean Rhodes <sean@starlabs.systems> 1681890435 +0100
committer Lean Sheng Tan <sheng.tan@9elements.com> 1687177659 +0000

soc/intel/cometlake: Enable early caching of RAMTOP region

Enable early caching of the TOM region to optimize the boot time by
selecting `SOC_INTEL_COMMON_BASECODE_RAMTOP` config.

Purpose of this feature is to cache the TOM (with a fixed size of
16MB) for all consecutive boots even before calling into the FSP.
Otherwise, this range remains un-cached until postcar boot stage
updates the MTRR programming. FSP-M and late romstage uses this
uncached TOM range for various purposes (like relocating services
between SPI mapped cached memory to DRAM based uncache memory) hence
having the ability to cache this range beforehand would help to
optimize the boot time (more than 50ms as applicable).

Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Change-Id: I579f85e84e0aba7f192ff81a6725d65b7f79ff75
Reviewed-on: https://review.coreboot.org/c/coreboot/+/74517
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>