Re: [PATCH v4 5/6] hwmon: (peci/cputemp) Add support for Granite Rapids (GNR)

[Guenter Roeck <linux@roeck-us.net>]

On Mon, Oct 19, 2026 at 04:45:01AM -0700, Changhuang Liang wrote:
> Add Granite Rapids (GNR) CPU support to the PECI cputemp driver.
> 
> For Granite Rapids, the resolved cores mask must be collected from each
> compute core. This implementation is relatively complex. Since we do not
> use the resolved cores information for these CPUs, we can explicitly
> state in the driver that the core mask is not supported for this model.
> 
> Define new cpu_info structure for GNR with minimum PECI revision 0x42 and
> the thermal margin conversion function dts_ten_dot_six_to_millidegree().
> 
> Signed-off-by: Changhuang Liang <changhuang.liang@starfivetech.com>
> Reviewed-by: Iwona Winiarska <iwona.winiarska@intel.com>

Acked-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  drivers/hwmon/peci/cputemp.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/drivers/hwmon/peci/cputemp.c b/drivers/hwmon/peci/cputemp.c
> index 457089c561b4..69c4a07b99f7 100644
> --- a/drivers/hwmon/peci/cputemp.c
> +++ b/drivers/hwmon/peci/cputemp.c
> @@ -339,6 +339,18 @@ static int init_core_mask(struct peci_cputemp *priv)
>  	u32 data;
>  	int ret;
>  
> +	/*
> +	 * For Granite Rapids, the resolved cores mask is relatively complex to implement.
> +	 * Since we do not use the resolved cores information for this CPU, the driver
> +	 * explicitly does not support the core mask for this model.
> +	 */
> +	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 +555,11 @@ 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 = 0x42,
> +	.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 +593,10 @@ 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);