mb/google/rex/var/baseboard/ovis: Support CPU power limits per variant

There is no direct way to override CPU default power_limits for
different SKUs.

This CL add structure variant_get_soc_power_limit_config() for
variants to define and configure the values of soc_power_limits_config
for current CPU SKU.

Variants can override these values i.e. pl1, pl2, psyspl2
in variant_devtree_update().

BUG=b:320410462
BRANCH=firmware-rex-15709.B
TEST=FSP debug emerge-ovis coreboot intelfsp
     check overrides setting

Change-Id: Ib60fa4e3fc502d0aeb0c94ad46ba5a55b4dd027c
Signed-off-by: Tony Huang <tony-huang@quanta.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82199
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Eric Lai <ericllai@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

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

@@ -24,6 +24,9 @@ int variant_memory_sku(void);
 bool variant_is_half_populated(void);
 void variant_update_soc_chip_config(struct soc_intel_meteorlake_config *config);
 
+/* Get soc power limit config struct for current CPU sku */
+struct soc_power_limits_config *variant_get_soc_power_limit_config(void);
+
 enum s0ix_entry {
 	S0IX_EXIT,
 	S0IX_ENTRY,

src/mainboard/google/rex/variants/baseboard/ovis/ramstage.c

@@ -1,8 +1,35 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later */
 
 #include <baseboard/variants.h>
+#include <console/console.h>
 #include <device/pci_ids.h>
+#include <device/pci_ops.h>
 #include <intelblocks/power_limit.h>
+#include <soc/pci_devs.h>
+
+struct soc_power_limits_config *variant_get_soc_power_limit_config(void)
+{
+	config_t *config = config_of_soc();
+	uint16_t mchid = pci_s_read_config16(PCI_DEV(0, 0, 0), PCI_DEVICE_ID);
+	u8 tdp = get_cpu_tdp();
+	size_t i = 0;
+
+	if (mchid == 0xffff)
+		return NULL;
+
+	for (i = 0; i < ARRAY_SIZE(cpuid_to_mtl); i++) {
+		if (mchid == cpuid_to_mtl[i].cpu_id && tdp == cpuid_to_mtl[i].cpu_tdp) {
+			return &config->power_limits_config[cpuid_to_mtl[i].limits];
+		}
+	}
+
+	if (i == ARRAY_SIZE(cpuid_to_mtl)) {
+		printk(BIOS_ERR, "Cannot find correct ovis sku index.\n");
+		return NULL;
+	}
+
+	return NULL;
+}
 
 /*
  * SKU_ID, TDP (Watts), pl1_min (milliWatts), pl1_max (milliWatts),