diff options
| author | Felix Held <felix-coreboot@felixheld.de> | 2024-07-30 15:24:08 +0200 |
|---|---|---|
| committer | Felix Held <felix-coreboot@felixheld.de> | 2024-07-31 20:07:17 +0000 |
| commit | e6c40f62724c9d0157b5b102c01aade30bc4c47e (patch) | |
| tree | 6b951d4eb3b2b44c136489a7b3098c218b670345 /src/soc/amd/common | |
| parent | 9c366417dfca97cb3aacfaf684ceafc18d6419e6 (diff) | |
soc/amd/common/psp_smm: add comments to psp_notify_smm
The reasoning behind this and the positive side effects of this aren't
too clear from the code, so point those out in a comment.
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I4f4121031fc1ef600cdf5551f61f1ef4e03b56a5
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83699
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@amd.corp-partner.google.com>
Diffstat (limited to 'src/soc/amd/common')
| -rw-r--r-- | src/soc/amd/common/block/psp/psp_smm.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/src/soc/amd/common/block/psp/psp_smm.c b/src/soc/amd/common/block/psp/psp_smm.c index 114cf12add..eecdf02be7 100644 --- a/src/soc/amd/common/block/psp/psp_smm.c +++ b/src/soc/amd/common/block/psp/psp_smm.c @@ -47,6 +47,13 @@ static void clear_smm_flag(void) smm_flag = 0; } +/* + * The MBOX_BIOS_CMD_SMM_INFO PSP mailbox command doesn't necessarily need be sent from SMM, + * but doing so allows the linker to sort out the addresses of c2p_buffer, p2c_buffer and + * smm_flag without us needing to pass this info between ramstage and smm. In the PSP gen2 case + * this will also make sure that the PSP MMIO base will be cached in SMM before the OS takes + * over so no SMN accesses will be needed during OS runtime. + */ int psp_notify_smm(void) { msr_t msr; |