[S] Change in coreboot[master]: device/pci_rom: Set VBIOS checksum when filling VFCT table

[Martin L Roth (Code Review)]

Attention is currently required from: CoolStar, Paul Menzel.

Martin L Roth has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/77628?usp=email )

Change subject: device/pci_rom: Set VBIOS checksum when filling VFCT table
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Patch Set 1:

(3 comments)

File src/device/pci_rom.c:

https://review.coreboot.org/c/coreboot/+/77628/comment/000b5f65_cdac369e :
PS1, Line 221: #define ATOMBIOS_CHECKSUM_OFFSET  0x21
Would it make more sense to put this in a header file like acpi/acpi.h along with the acpi_vfct_image_hdr structure?

https://review.coreboot.org/c/coreboot/+/77628/comment/66d2ec0b_f8a7b176 :
PS1, Line 254: 	/* Calculate checksum for VBIOS data. */
I don't think that this is something that can be done universally. It's looks like it's overwriting the 3rd byte of the 4-byte Option Rom "Init Entry" field. We should probably make sure that this is only run on AtomBIOS option ROMs that will just be used for the GOP driver.

See table A2 on page 33 of the Bios Boot Specification V1.01

https://www.intel.com/content/www/us/en/content-details/772756/bios-boot-spe...

File src/include/acpi/acpi.h:

https://review.coreboot.org/c/coreboot/+/77628/comment/9cfd2cb3_68f52b97 :
PS1, Line 481:  VbiosContent[1]
We're actually getting rid of all 0 & 1 length arrays in coreboot right now.
Please change this to a C99 flexible array: `VbiosContent[];`

See https://developers.redhat.com/articles/2022/09/29/benefits-limitations-flexi...