Kyösti Mälkki has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/42073 )
Change subject: [WIP] sb,soc/amd: Allow dynamic ACPIMMIO base address ......................................................................
Patch Set 1:
(1 comment)
https://review.coreboot.org/c/coreboot/+/42073/1/src/soc/amd/common/block/ac... File src/soc/amd/common/block/acpimmio/mmio_util.c:
https://review.coreboot.org/c/coreboot/+/42073/1/src/soc/amd/common/block/ac... PS1, Line 32: update_acpimmio_base
The psp maps each block individually. See https://source.chromium. […]
I am not setup to build for PSP and I don't have documentation access either.
Not sure if there is some actual IOMMU, and each bank mapping eats a resource from that. Maybe there is some security implication why they did not allow mapping the entire ACPIMMIO space as one 8 kB block. Or then it was just never requested?
If you come up with a need for verstage to access some new bank, you are looking at changes to PSP kernel to implmement additional service calls for the new mapping...