[coreboot-gerrit] [M] Change in coreboot[master]: soc/intel/meteorlake: transition full control over PM Timer from FSP ...

[Felix Held (Code Review)]

Felix Held has submitted this change. ( https://review.coreboot.org/c/coreboot/+/69613 )

Change subject: soc/intel/meteorlake: transition full control over PM Timer from FSP to coreboot
......................................................................

soc/intel/meteorlake: transition full control over PM Timer from FSP to coreboot

Set `EnableTcoTimer=1` in order to keep FSP from
 1) enabling ACPI Timer emulation in uCode.
 2) disabling the PM ACPI Timer.

Both actions are now done in coreboot.

`EnableTcoTimer=1` makes FSP skip these steps in any possible case
including `SkipMpInit=0`, `SkipMpInit=1`, use of the MP PPI or FSP
Multiphase Init. This way full control is left to coreboot.

Port of commit 0e905801f8ff ("soc/intel: transition full control over PM
Timer from FSP to coreboot").

NOTE: This will have a huge power impact when it's enabled. If TCO timer
is disabled, uCode ACPI timer emulation must be enabled, and WDAT table
must not be exposed to the OS.

BUG=none
TEST=Boot to OS on google/rex.

Excerpt from google/rex coreboot log:
[SPEW ]   EnableTcoTimer                      = 1

Signed-off-by: Kapil Porwal 
Change-Id: I2693f0390e6c9fa92fec366ab87589c3bcea9027
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69613
Tested-by: build bot (Jenkins) 
Reviewed-by: Subrata Banik 
---
M src/soc/intel/meteorlake/fsp_params.c
1 file changed, 50 insertions(+), 0 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Subrata Banik: Looks good to me, approved

diff --git a/src/soc/intel/meteorlake/fsp_params.c b/src/soc/intel/meteorlake/fsp_params.c
index 4429dc0..2e1820e 100644
--- a/src/soc/intel/meteorlake/fsp_params.c
+++ b/src/soc/intel/meteorlake/fsp_params.c
@@ -349,6 +349,19 @@
    s_cfg->Enable8254ClockGatingOnS3 = !CONFIG(USE_LEGACY_8254_TIMER);
 }

+static void fill_fsps_pm_timer_params(FSP_S_CONFIG *s_cfg,
+		const struct soc_intel_meteorlake_config *config)
+{
+	/*
+	 * Legacy PM ACPI Timer (and TCO Timer)
+	 * This *must* be 1 in any case to keep FSP from
+	 *  1) enabling PM ACPI Timer emulation in uCode.
+	 *  2) disabling the PM ACPI Timer.
+	 * We handle both by ourself!
+	 */
+	s_cfg->EnableTcoTimer = 1;
+}
+
 static void fill_fsps_pcie_params(FSP_S_CONFIG *s_cfg,
    	const struct soc_intel_meteorlake_config *config)
 {
@@ -429,6 +442,7 @@
    	fill_fsps_vmd_params,
    	fill_fsps_tbt_params,
    	fill_fsps_8254_params,
+		fill_fsps_pm_timer_params,
    	fill_fsps_pcie_params,
    	fill_fsps_misc_power_params,
    	fill_fsps_ufs_params,