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

[Winiarska, Iwona]

On Thu, 2026-09-03 at 06:34 -0700, Changhuang Liang wrote:
> 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

PECI revision for GNR is 4.2.

Thanks
-Iwona

> the thermal margin conversion function dts_ten_dot_six_to_millidegree().
> 
> Signed-off-by: Changhuang Liang <changhuang.liang@xxxxxxxxxxxxxxxx>
> ---
>  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);