mb/google/brox: Fix booting to kernel without battery

When battery is disconnected and only adaptor is connected higher PL2
power draw causes cpu brown out and system does not boot to kernel. To
avoid this set Boot frequency UPD to 1. Reduce PL4 value to overcome
power spikes from SoC during boot. Remove Psys implementation as it
impacts active state platform performance.

BUG=b:335046538,b:329722827
BRANCH=None
TEST=Able to successfully boot on 3 different Brox proto2 SKU1
     and SKU2 boards with 65W, 45W and 30W adaptors for 3
     iterations of cold boot.
Change-Id: I58e136c607ea9290ecac0cee453d6632760a6433
Signed-off-by: Sowmya Aralguppe <sowmya.aralguppe@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83752
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>

4 files changed, 52 insertions, 23 deletions

diff --git a/src/mainboard/google/brox/Kconfig b/src/mainboard/google/brox/Kconfig
index a1d284b553..8fd43f4cb7 100644
--- a/src/mainboard/google/brox/Kconfig
+++ b/src/mainboard/google/brox/Kconfig
@@ -117,6 +117,19 @@ config DRIVER_TPM_I2C_BUS
 	hex
 	default 0x4 if BOARD_GOOGLE_BASEBOARD_BROX
 
+config PL4_LIMIT_FOR_CRITICAL_BAT_BOOT
+	int
+	default 9
+	help
+	  Select this if the variant has to boot even with low battery, critical battery
+	  threshold, or when the battery is physically disconnected. PL4, which stands for
+	  Processor Instantaneous Power or Absolute Peak Power, controls the highest power draw
+	  from the processor at any given moment within the Pl1Tau duration. Therefore, PL4
+	  acts as a failsafe mechanism to set an upper threshold limit for the processor's
+	  instantaneous power draw. For a 30W adapter, the maximum peak power is set at 9
+	  watts, which is 30W multiplied by 32% efficiency. This default pl4 value is set for
+	  30W or any higher adapter rating, such as 45W or 65W.
+
 config DRIVER_TPM_I2C_ADDR
 	hex
 	default 0x50
diff --git a/src/mainboard/google/brox/romstage.c b/src/mainboard/google/brox/romstage.c
index 4e88eca617..ced918457d 100644
--- a/src/mainboard/google/brox/romstage.c
+++ b/src/mainboard/google/brox/romstage.c
@@ -2,6 +2,7 @@
 
 #include <baseboard/gpio.h>
 #include <baseboard/variants.h>
+#include <ec/google/chromeec/ec.h>
 #include <fsp/api.h>
 #include <gpio.h>
 #include <soc/romstage.h>
@@ -19,6 +20,14 @@ void mainboard_memory_init_params(FSPM_UPD *memupd)
 	const struct pad_config *pads;
 	size_t pads_num;
 
+	/* If battery is not present - Boot with maximum non-turbo frequency */
+	if (CONFIG(EC_GOOGLE_CHROMEEC) &&
+			!google_chromeec_is_battery_present_and_above_critical_threshold()) {
+		FSP_M_CONFIG *mem_cfg = &memupd->FspmConfig;
+		mem_cfg->BootFrequency = MAX_NONTURBO_PERFORMANCE;
+		printk(BIOS_DEBUG, "Boot Frequency is set to %u\n", mem_cfg->BootFrequency);
+	}
+
 	memcfg_init(memupd, mem_config, &spd_info, half_populated);
 
 	pads = variant_romstage_gpio_table(&pads_num);
diff --git a/src/mainboard/google/brox/variants/baseboard/brox/ramstage.c b/src/mainboard/google/brox/variants/baseboard/brox/ramstage.c
index 038255f98e..85c3c488fa 100644
--- a/src/mainboard/google/brox/variants/baseboard/brox/ramstage.c
+++ b/src/mainboard/google/brox/variants/baseboard/brox/ramstage.c
@@ -42,13 +42,27 @@ static bool get_sku_index(const struct cpu_power_limits *limits, size_t num_entr
 	}
 
 	if (i == num_entries) {
-		printk(BIOS_ERR, "Cannot find correct brox sku index (mchid = %u).\n", mchid);
+		printk(BIOS_ERR, "Cannot find brox sku index (mchid = %u)\n", mchid);
 		return false;
 	}
 
 	return true;
 }
 
+static void variant_pl4_override(struct soc_power_limits_config *config,
+					const struct cpu_power_limits *limits, size_t brox_idx)
+{
+	if (!config->tdp_pl4)
+		return;
+
+	/* limiting PL4 value for battery disconnected or below critical threshold */
+	if (CONFIG_PL4_LIMIT_FOR_CRITICAL_BAT_BOOT &&
+	     (!google_chromeec_is_battery_present_and_above_critical_threshold()))
+		config->tdp_pl4 = CONFIG_PL4_LIMIT_FOR_CRITICAL_BAT_BOOT;
+	else
+		config->tdp_pl4 = DIV_ROUND_UP(limits[brox_idx].pl4_power, MILLIWATTS_TO_WATTS);
+}
+
 void variant_update_power_limits(const struct cpu_power_limits *limits, size_t num_entries)
 {
 	const struct device *policy_dev;
@@ -61,30 +75,33 @@ void variant_update_power_limits(const struct cpu_power_limits *limits, size_t n
 	if (!num_entries)
 		return;
 
-	policy_dev = DEV_PTR(dptf_policy);
-	if (!policy_dev)
-		return;
-
 	if (!get_sku_index(limits, num_entries, &intel_idx, &brox_idx))
 		return;
 
-	config = policy_dev->chip_info;
-	settings = &config->controls.power_limits;
 	conf = config_of_soc();
 	soc_config = &conf->power_limits_config[intel_idx];
+	variant_pl4_override(soc_config, limits, brox_idx);
+
+	policy_dev = DEV_PTR(dptf_policy);
+	if (!policy_dev) {
+		printk(BIOS_INFO, "DPTF policy not set\n");
+		return;
+	}
+	config = policy_dev->chip_info;
+	settings = &config->controls.power_limits;
 	settings->pl1.min_power = limits[brox_idx].pl1_min_power;
 	settings->pl1.max_power = limits[brox_idx].pl1_max_power;
 	settings->pl2.min_power = limits[brox_idx].pl2_min_power;
 	settings->pl2.max_power = limits[brox_idx].pl2_max_power;
 
 	if (soc_config->tdp_pl2_override != 0) {
-		settings->pl2.max_power = soc_config->tdp_pl2_override * 1000;
+		settings->pl2.max_power = soc_config->tdp_pl2_override * MILLIWATTS_TO_WATTS;
 		settings->pl2.min_power = settings->pl2.max_power;
 	}
 
-	if (soc_config->tdp_pl4 == 0)
-		soc_config->tdp_pl4 = DIV_ROUND_UP(limits[brox_idx].pl4_power,
-						MILLIWATTS_TO_WATTS);
+	printk(BIOS_INFO, "Overriding power limits PL1 (%u, %u) PL2 (%u, %u) PL4 (%u)\n",
+		settings->pl1.min_power, settings->pl1.max_power, settings->pl2.min_power,
+		settings->pl2.max_power, soc_config->tdp_pl4);
 }
 
 /*
@@ -138,7 +155,8 @@ void variant_update_psys_power_limits(const struct cpu_power_limits *limits,
 		watts = ((u32)current_ma * volts_mv) / 1000000;
 	}
 	/* If battery is present and has enough charge, add discharge rate */
-	if (CONFIG(EC_GOOGLE_CHROMEEC) && google_chromeec_is_battery_present_and_above_critical_threshold()) {
+	if (CONFIG(EC_GOOGLE_CHROMEEC) &&
+		google_chromeec_is_battery_present_and_above_critical_threshold()) {
 		watts += 65;
 	}
 
diff --git a/src/mainboard/google/brox/variants/brox/ramstage.c b/src/mainboard/google/brox/variants/brox/ramstage.c
index 78e03caccb..aef7a00f72 100644
--- a/src/mainboard/google/brox/variants/brox/ramstage.c
+++ b/src/mainboard/google/brox/variants/brox/ramstage.c
@@ -33,16 +33,6 @@ const struct cpu_power_limits performance_efficient_limits[] = {
 	},
 };
 
-const struct system_power_limits sys_limits[] = {
-	/* SKU_ID, TDP (Watts), psys_pl2 (Watts) */
-	{ PCI_DID_INTEL_RPL_P_ID_3, 15, 60 },
-	{ PCI_DID_INTEL_RPL_P_ID_4, 15, 60 },
-};
-
-const struct psys_config psys_config = {
-	.efficiency = 86,
-};
-
 void __weak variant_devtree_update(void)
 {
 	uint32_t board_version = board_id();
@@ -52,7 +42,6 @@ void __weak variant_devtree_update(void)
 	size_t limits_size = ARRAY_SIZE(performance_efficient_limits);
 
 	variant_update_power_limits(limits, limits_size);
-	variant_update_psys_power_limits(limits, sys_limits, limits_size, &psys_config);
 
 	/* Disable I2C bus device for Touchscreen */
 	if (board_version >= 1) {