[PATCH v1 5/6] hwmon: (peci/cputemp) Add support for Granite Rapids (GNR)

[Changhuang Liang <changhuang.liang@starfivetech.com>]

Add Granite Rapids (GNR) CPU support to the PECI cputemp driver. The GNR
platform does not support the core mask scan via PCI local read, so
handle this case explicitly by returning -EPERM and skipping the core
mask initialization.

Define new cpu_info structure for GNR with minimum PECI revision 0x40 and
the thermal margin conversion function dts_ten_dot_six_to_millidegree().

Signed-off-by: Changhuang Liang <changhuang.liang@starfivetech.com>
---
 drivers/hwmon/peci/cputemp.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/hwmon/peci/cputemp.c b/drivers/hwmon/peci/cputemp.c
index 457089c561b4..43e52a6db79b 100644
--- a/drivers/hwmon/peci/cputemp.c
+++ b/drivers/hwmon/peci/cputemp.c
@@ -339,6 +339,17 @@ static int init_core_mask(struct peci_cputemp *priv)
 	u32 data;
 	int ret;
 
+	/*
+	 * Some platforms (e.g. Granite Rapids) do not expose the RESOLVED_CORES
+	 * register over PECI - per-core temperatures are simply not available.
+	 */
+	if (!reg) {
+		dev_dbg(priv->dev,
+			"resolved cores scan is not supported on vendor-family-model 0x%x\n",
+			peci_dev->info.x86_vfm);
+		return -EOPNOTSUPP;
+	}
+
 	/* Get the RESOLVED_CORES register value */
 	switch (peci_dev->info.x86_vfm) {
 	case INTEL_ICELAKE_X:
@@ -543,6 +554,11 @@ static const struct cpu_info cpu_emr = {
 	.thermal_margin_to_millidegree = &dts_ten_dot_six_to_millidegree,
 };
 
+static const struct cpu_info cpu_gnr = {
+	.min_peci_revision = 0x40,
+	.thermal_margin_to_millidegree = &dts_ten_dot_six_to_millidegree,
+};
+
 static const struct auxiliary_device_id peci_cputemp_ids[] = {
 	{
 		.name = "peci_cpu.cputemp.hsx",
@@ -576,6 +592,10 @@ static const struct auxiliary_device_id peci_cputemp_ids[] = {
 		.name = "peci_cpu.cputemp.emr",
 		.driver_data = (kernel_ulong_t)&cpu_emr,
 	},
+	{
+		.name = "peci_cpu.cputemp.gnr",
+		.driver_data = (kernel_ulong_t)&cpu_gnr,
+	},
 	{ }
 };
 MODULE_DEVICE_TABLE(auxiliary, peci_cputemp_ids);
-- 
2.25.1