tree b05b8f222ddd6027f7a9ee15bcfe9c82f9ebfbf2
parent a464af451e4765cfb65b65fbe9314c309a1671b3
author Subrata Banik <subratabanik@google.com> 1673861702 +0530
committer Sridhar Siricilla <sridhar.siricilla@intel.com> 1674031308 +0000

soc/intel/cannonlake: Fix incorrect `prev_sleep_state` issue

The patch fixes indication of incorrect `prev_sleep_state` on the next
boot after global reset trigger. The existing code misses an important check about `if PCH doesn't set the WAK_STS` while checking power
failure. As a result, every early warm/global reset is considered
as power failure after looking into the PMC MMIO CON-A register
alone (as ignoring the ACPI PM_CTRL.WAK_STS bit).

As per the code comment this code logic is expected to check the power
failure reason if PCH doesn't set the WAK_STS while waking from G3
state.

TEST=Able to build and boot google/hatch.

Without this patch:

Observation: Resuming after a warm reset is considered as
`prev_sleep_state 5` although the SLP_TYP is zero and WAK_STS bit
is set.

    pm1_sts: 8100 pm1_en: 0000 pm1_cnt: 00000000
    GEN_PMCON: d1215238 00002200
    ....
    prev_sleep_state 5

With this patch:

Observation: Resuming after a warm reset is considered as
`prev_sleep_state 0`. It matches with the SLP_TYP is zero and
WAK_STS bit is set.

    pm1_sts: 8100 pm1_en: 0000 pm1_cnt: 00000000
    GEN_PMCON: d1215238 00002200
    ....
    prev_sleep_state 0

Signed-off-by: Subrata Banik <subratabanik@google.com>
Change-Id: I05a2fab75c3d931651885db0003ab8c5748a1568
Reviewed-on: https://review.coreboot.org/c/coreboot/+/71934
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>
Reviewed-by: Sean Rhodes <sean@starlabs.systems>
Reviewed-by: Sridhar Siricilla <sridhar.siricilla@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>