mb/google/{rex,ovis}: Disable package C-state auto demotion

Package C-state auto demotion feature allows hardware to determine lower
C-state as per platform policy. Since platform sets performance policy
to balanced from hardware, auto demotion can be disabled without
performance impact.

Also, disabling this feature results soc to enter below PC8 state and
additional power savings ~30mW in Local-Video-Playback scenario.

BUG=b:303546334
TEST=Local build successfully & Boot to OS successfully
 - Also check platform enter PC8 state in local video playback
 - before this change: # iotools rdmsr 0 0xE2 -> 0x0000000060008008
 - After # iotools rdmsr 0 0xE2 -> 0x0000000000008008

Change-Id: Ia4cf4a7cb6bd5eaae26197b55f9385c078960d7b
Signed-off-by: Sukumar Ghorai <sukumar.ghorai@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78250
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Eric Lai <ericllai@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>

src/mainboard/google/rex/variants/baseboard/ovis/devicetree.cb

@@ -36,6 +36,9 @@ chip soc/intel/meteorlake
 	# Disable C1 C-state auto-demotion
 	register "disable_c1_state_auto_demotion" = "1"
 
+	# Disable PKGC-state demotion
+	register "disable_package_c_state_demotion" = "1"
+
 	# Enable Energy Reporting
 	register "pch_pm_energy_report_enable" = "1"
 

src/mainboard/google/rex/variants/baseboard/rex/devicetree.cb

@@ -36,6 +36,9 @@ chip soc/intel/meteorlake
 	# Disable C1 C-state auto-demotion
 	register "disable_c1_state_auto_demotion" = "1"
 
+	# Disable PKGC-state demotion
+	register "disable_package_c_state_demotion" = "1"
+
 	# Enable Energy Reporting
 	register "pch_pm_energy_report_enable" = "1"
 

src/soc/intel/meteorlake/chip.h

@@ -419,6 +419,8 @@ struct soc_intel_meteorlake_config {
 	 * Enable or Disable Package C-state Demotion.
 	 * Default is set to 0.
 	 * Set this to 1 in order to disable Package C-state demotion.
+	 * NOTE: Un-Demotion from demoted Package C-state needs to be disabled
+	 *       when auto demotion is disabled.
 	 */
 	bool disable_package_c_state_demotion;
 

src/soc/intel/meteorlake/fsp_params.c

@@ -666,6 +666,7 @@ static void fill_fsps_misc_power_params(FSP_S_CONFIG *s_cfg,
 	s_cfg->C1StateUnDemotion = !config->disable_c1_state_auto_demotion;
 	s_cfg->C1StateAutoDemotion = !config->disable_c1_state_auto_demotion;
 	s_cfg->PkgCStateDemotion = !config->disable_package_c_state_demotion;
+	s_cfg->PkgCStateUnDemotion = !config->disable_package_c_state_demotion;
 	s_cfg->PmcV1p05PhyExtFetControlEn = 1;
 
 	/* Enable PCH to CPU energy report feature. */