[M] Change in coreboot[main]: soc/amd/common/block/lpc: Use ROM3 window if possible

[Patrick Rudolph (Code Review)]

Attention is currently required from: Felix Held, Fred Reitberger, Jason Glenesk, Martin L Roth, Matt DeVillier, Maximilian Brune, Paul Menzel, Varshit Pandya.

Patrick Rudolph has posted comments on this change by Patrick Rudolph. ( https://review.coreboot.org/c/coreboot/+/86584?usp=email )

Change subject: soc/amd/common/block/lpc: Use ROM3 window if possible
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Patch Set 11:

(1 comment)

File src/soc/amd/common/block/spi/mmap_boot_rom3.c:

https://review.coreboot.org/c/coreboot/+/86584/comment/d4347ae7_3417cacb?usp... :
PS11, Line 62:  *             0   +------------+ ------------------------------0xFF0000000--+--------------+- rom2_start
> hmm, i don't like that smmstorev2 interface design too much and i still don't think that we should o […]

Document 56780 describes the remapping for ROM3 as well.
Reading through the document it sounds remapping isn't yet supported.

You would need another valid EFS in the second 16MByte page as well as all necessary structures to boot (FMAP, CBFS, ...).