[M] Change in coreboot[main]: drivers/option: Add CBFS file based option backend

[Nicholas Chin (Code Review)]

Attention is currently required from: Julius Werner, Subrata Banik.

Nicholas Chin has posted comments on this change by Nicholas Chin. ( https://review.coreboot.org/c/coreboot/+/85905?usp=email )

Change subject: drivers/option: Add CBFS file based option backend
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Patch Set 8:

(3 comments)

Patchset:

PS2:
> Oh, I didn't notice this by the time I pushed a new patchset. […]

@[e-mail] If it makes things easier feel free to push new patchsets. I won't be able to get back to this until later in the day.

File src/drivers/option/Makefile.mk:

https://review.coreboot.org/c/coreboot/+/85905/comment/d84eafa2_2567cf93?usp... :
PS6, Line 6: smm-$(CONFIG_USE_CBFS_FILE_OPTION_BACKEND) += cbfs_file_option.c
> > as we don't compile vboot library in smm mode, I'm getting compilation error due to undefined refe […]

Seems like the only user of the option api in SMM is the `power_on_after_fail` option, which defaults to a a value that can be set by Kconfig. So there isn't much lost by removing the ability to configure options in SMM, and keeping SMM as simple as possible and having fewer possible SMM runtime codepaths is probably not a bad idea anyway.

File src/include/option.h:

https://review.coreboot.org/c/coreboot/+/85905/comment/4f15264b_62273f9a?usp... :
PS7, Line 10: #if CONFIG(OPTION_BACKEND_NONE)
>

Done