Aaron Durbin has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/38512 )
Change subject: soc/intel/skylake: Only reserve TPM area for !CONFIG_TPM_CR50 device ......................................................................
Patch Set 3:
(1 comment)
https://review.coreboot.org/c/coreboot/+/38512/3/src/soc/intel/skylake/acpi/... File src/soc/intel/skylake/acpi/systemagent.asl:
https://review.coreboot.org/c/coreboot/+/38512/3/src/soc/intel/skylake/acpi/... PS3, Line 185: #if !CONFIG(TPM_CR50)
This is the confusing part: While TIS assumes that a SPI TPM has memory-mapped […]
'#if CONFIG(LPC_TPM)' is not necessarily correct either. I believe we need a semantic that specifically indicates memory mapped TPM that conforms to the PC client TPM spec (didn't want to locate the exact one).
https://trustedcomputinggroup.org/resources/?workgroups=PC%20Client&
However the memory mapped TPM support is provided is actually agnostic to the interconnect. For CR50 purposes, I can confirm it can't be used with current memory mapping assist, and I'm fairly certain we don't implement PC client spec fully.