mb/google/brya: create dynamic power limits mechanism for thermal

Add dynamic power limits selection mechanism for brya board based on
CPU SKUs which is detectable at runtime.

BUG=b:194745919
BRANCH=None
TEST=Build FW and test on brya with below messages,
 On brya (282):
  Overriding DPTF power limits PL1 (3000, 15000) PL2 (39000, 39000)
 On brya (482):
  Overriding DPTF power limits PL1 (4000, 28000) PL2 (43000, 43000)

Change-Id: I86619516adeec13642f02ba7faf9fc4945ad774e
Signed-off-by: Sumeet Pawnikar <sumeet.r.pawnikar@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/56515
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>

src/mainboard/google/brya/mainboard.c

@@ -26,6 +26,13 @@ static void mainboard_init(void *chip_info)
 	base_pads = variant_gpio_table(&base_num);
 	override_pads = variant_gpio_override_table(&override_num);
 	gpio_configure_pads_with_override(base_pads, base_num, override_pads, override_num);
+
+	variant_devtree_update();
+}
+
+void __weak variant_devtree_update(void)
+{
+	/* Override dev tree settings per board */
 }
 
 static void mainboard_dev_init(struct device *dev)

src/mainboard/google/brya/variants/baseboard/brya/Makefile.inc

@@ -3,3 +3,4 @@ bootblock-y += gpio.c
 romstage-y += memory.c
 
 ramstage-y += gpio.c
+ramstage-y += ramstage.c

src/mainboard/google/brya/variants/baseboard/brya/ramstage.c

@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <acpi/acpi_device.h>
+#include <baseboard/variants.h>
+#include <console/console.h>
+#include <device/pci_ops.h>
+#include <soc/pci_devs.h>
+
+#include <drivers/intel/dptf/chip.h>
+
+void variant_update_power_limits(const struct cpu_power_limits *limits, size_t num_entries)
+{
+	if (!num_entries)
+		return;
+
+	const struct device_path policy_path[] = {
+		{ .type = DEVICE_PATH_PCI, .pci.devfn = SA_DEVFN_DPTF},
+		{ .type = DEVICE_PATH_GENERIC, .generic.id = 0}
+	};
+
+	const struct device *policy_dev = find_dev_nested_path(pci_root_bus(),
+							policy_path, ARRAY_SIZE(policy_path));
+	if (!policy_dev)
+		return;
+
+	struct drivers_intel_dptf_config *config = policy_dev->chip_info;
+
+	uint16_t mchid = pci_s_read_config16(PCI_DEV(0, 0, 0), PCI_DEVICE_ID);
+
+	for (size_t i = 0; i < num_entries; i++) {
+		if (mchid == limits[i].mchid) {
+			struct dptf_power_limits *settings = &config->controls.power_limits;
+			settings->pl1.min_power = limits[i].pl1_min_power;
+			settings->pl1.max_power = limits[i].pl1_max_power;
+			settings->pl2.min_power = limits[i].pl2_min_power;
+			settings->pl2.max_power = limits[i].pl2_max_power;
+			printk(BIOS_INFO, "Overriding DPTF power limits PL1 (%u, %u) PL2 (%u, %u)\n",
+					limits[i].pl1_min_power,
+					limits[i].pl1_max_power,
+					limits[i].pl2_min_power,
+					limits[i].pl2_max_power);
+		}
+	}
+}

src/mainboard/google/brya/variants/baseboard/include/baseboard/variants.h

@@ -22,4 +22,19 @@ int variant_memory_sku(void);
 bool variant_is_half_populated(void);
 void variant_update_soc_chip_config(struct soc_intel_alderlake_config *config);
 
+/* Modify devictree settings during ramstage */
+void variant_devtree_update(void);
+
+struct cpu_power_limits {
+	uint16_t mchid;
+	unsigned int pl1_min_power;
+	unsigned int pl1_max_power;
+	unsigned int pl2_min_power;
+	unsigned int pl2_max_power;
+};
+
+/* Modify Power Limit devictree settings during ramstage */
+void variant_update_power_limits(const struct cpu_power_limits *limits,
+									size_t num_entries);
+
 #endif /*__BASEBOARD_VARIANTS_H__ */