[XS] Change in coreboot[main]: drivers/vpd: Return NULL for missing "feature_device_info"

[Subrata Banik (Code Review)]

Attention is currently required from: Gwendal Grignou, Nick Vaccaro, Shelley Chen.

Subrata Banik has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/80805?usp=email )

Change subject: drivers/vpd: Return NULL for missing "feature_device_info"
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Patch Set 1:

(1 comment)

File src/drivers/vpd/vpd_device_feature.c:

https://review.coreboot.org/c/coreboot/+/80805/comment/45356a99_98508781 :
PS1, Line 10: 	static char device_info[VPD_FEATURE_DEVICE_INFO_LEN];
> > Could |device_info| be in the stack and give as an argument to the function? The function is called only once and there is no logic to cache the data.
>
> in that case the caller (outside drivers/vpd) of the vpd_get_feature_device_info() has to pass the `device_info` buffer and also needs to know the possible size (VPD_FEATURE_DEVICE_INFO_LEN) which may not required to be exposed outside of this file.
>
> I don't think there is any problem of using static variable as we are in ramstage (and there is no memory specific restriction)

more reference here, https://github.com/coreboot/coreboot/blob/main/src/drivers/vpd/vpd_serial.c#...

I don't see any caller of VPD API are actually passing the argument over stack.