[coreboot-gerrit] Change in coreboot[master]: intel/fsp2_0: Add soc_validate_fsp_version for FSP version check

[Jonathan Zhang (Code Review)]

Jonathan Zhang has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/47559 )

Change subject: intel/fsp2_0: Add soc_validate_fsp_version for FSP version check
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Patch Set 1:

Hi,

So far CPX-SP FSP releases do not have version updated. If the FSP binary and coreboot (in particular FSP header files) are mismatched, serious problems happen, so it makes sense to add version check, and bail out loud and early when mismatch is detected.

We are pushing hard on Intel to version CPX-SP FSP releases appropriately. That being said, CPX-SP FSP engineering is winding down, so we do not have much wiggle room. The current (proposed) design is following:
The build number is the last digit with 8 bit encoding scheme:
|7             6|5 ………………  0|
|Year number % 4| WW number|
So the 6-bit can have 64 work weeks number, enough for a year, and the 2-bit year number can cover 4 year span (with 2020 as the first year).
Note that other fields (spec major/minor, rev major/minor/ver remain constant as 2.1-0.2.1.

Our plan is:
a. Update CPX-SP FSP version string display, for instance from 2.1-0.2.1.45 to 2.1-0.2.1-1.45. In other words, display the year number as well.
b. Add check in soc code [CB:47560] to check minimum/maximum required FSP binary version.
c. Work with Intel to make sure there is a sound design in this aspect for next generation xeon-sp FSP. I am not sure whether utilizing FirmwareVersionInfoHob.h is a good idea.

Your feedback is appreciated. We need to close on this quickly.

Thanks,
Jonathan