[M] Change in coreboot[master]: mb/google/skyrim: Use CMOS bit to toggle ABL WA for Hynix DRAM

[Matt DeVillier (Code Review)]

Attention is currently required from: Felix Held, Jason Glenesk, Jason Nien, Karthik Ramasubramanian, Martin Roth, Paul Menzel.

Matt DeVillier has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/75698?usp=email )

Change subject: mb/google/skyrim: Use CMOS bit to toggle ABL WA for Hynix DRAM
......................................................................

Patch Set 3:

(5 comments)

File src/mainboard/google/skyrim/bootblock.c:

https://review.coreboot.org/c/coreboot/+/75698/comment/c93a78b6_aa7874d8 :
PS2, Line 17: 18
> Agreed - I was more thinking about creating the cbi_part_number array though.

I'm using the full length allowed the SPD spec for the cbi_part_number array, which is 33 bytes, so no concern there

https://review.coreboot.org/c/coreboot/+/75698/comment/188732d8_ae32f282 :
PS2, Line 43: 	/* If problematic Hynix module, ensure bit set */
> I think if we're worried about it, we should get rid of most of the log messages. […]

they're all filtered on SPEW level already, so do we really care if there are too many?

https://review.coreboot.org/c/coreboot/+/75698/comment/1253eae1_4627e8ea :
PS2, Line 94: hynix_dram_cmos_check();
> YAGNI. […]

I'm perfectly happy to just restict this to just FF, adding another Kconfig seems unnecessary

File src/mainboard/google/skyrim/bootblock.c:

https://review.coreboot.org/c/coreboot/+/75698/comment/558ffd93_082cdaf7 :
PS3, Line 32: google_chromeec_cbi_get_dram_part_num
> Part of the reason I was asking for the termination byte for the string is just because I don't have […]

since it's passed directly to the EC via a host cmd, it appears it would overflow if too short. cbi_get_string() ensures it's null-terminated

https://review.coreboot.org/c/coreboot/+/75698/comment/21d6f62f_2c9d2d4c :
PS3, Line 35: return;
> Should we clear the cmos bit in this case? Can we assume that if there's an error here, the bad hyni […]

I think there are reasonable arguments for leaving it and for clearing it. I don't have a preference either way