mb/google/rex/var/rex: Configure cpu power limits by battery status

When battery level is below critical level or battery is not present,
cpus need to run with a power optimized configuration to avoid platform
instabilities. This will check the current battery status and configure
cpu power limits properly.

BUG=b:296952944
TEST=Build rex0 and check cpu power limits are configured with
a performance efficient configuration and the platform boots to OS if
battery level is above the critical level. And check cpu power limits
are configured with a power optimized configuration and boots to OS
without an issue if battery is not present or battery level is at or
below critical level.

Change-Id: I12fd40abda76c8e7522b06a5aee72665f32ddec8
Signed-off-by: Jamie Ryu <jamie.m.ryu@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78322
Reviewed-by: Subrata Banik <subratabanik@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 30 insertions, 3 deletions

diff --git a/src/mainboard/google/rex/variants/baseboard/rex/ramstage.c b/src/mainboard/google/rex/variants/baseboard/rex/ramstage.c
index aee3d888a1..f33db733fa 100644
--- a/src/mainboard/google/rex/variants/baseboard/rex/ramstage.c
+++ b/src/mainboard/google/rex/variants/baseboard/rex/ramstage.c
@@ -2,6 +2,7 @@
 
 #include <baseboard/variants.h>
 #include <device/pci_ids.h>
+#include <ec/google/chromeec/ec.h>
 #include <intelblocks/power_limit.h>
 
 /*
@@ -9,7 +10,7 @@
  * pl2_min (milliWatts), pl2_max (milliWatts), pl4 (milliWatts)
  * Following values are for performance config as per document #640982
  */
-const struct cpu_tdp_power_limits limits[] = {
+const struct cpu_tdp_power_limits performance_efficient_limits[] = {
 	{
 		.mch_id = PCI_DID_INTEL_MTL_P_ID_2,
 		.cpu_tdp = 15,
@@ -21,8 +22,34 @@ const struct cpu_tdp_power_limits limits[] = {
 	},
 };
 
+const struct cpu_tdp_power_limits power_optimized_limits[] = {
+	{
+		.mch_id = PCI_DID_INTEL_MTL_P_ID_2,
+		.cpu_tdp = 15,
+		.pl1_min_power = 10000,
+		.pl1_max_power = 15000,
+		.pl2_min_power = 57000,
+		.pl2_max_power = 57000,
+		.pl4_power = 64000
+	},
+};
+
 void variant_devtree_update(void)
 {
-	size_t total_entries = ARRAY_SIZE(limits);
-	variant_update_cpu_power_limits(limits, total_entries);
+	const struct cpu_tdp_power_limits *limits = performance_efficient_limits;
+	size_t limits_size = ARRAY_SIZE(performance_efficient_limits);
+
+	/*
+	 * If battery is not present or battery level is at or below critical threshold
+	 * to boot a platform with the performance efficient configuration, boot with
+	 * the power optimized configuration.
+	 */
+	if (CONFIG(EC_GOOGLE_CHROMEEC)) {
+		if (!google_chromeec_is_battery_present_and_above_critical_threshold()) {
+			limits = power_optimized_limits;
+			limits_size = ARRAY_SIZE(power_optimized_limits);
+		}
+	}
+
+	variant_update_cpu_power_limits(limits, limits_size);
 }