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

[Changhuang Liang]

Hi, Guenter

Thanks for the review.

> On 9/3/26 06:34, 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.
> >
> 
> After reading the next patch of the series: Are you sure that this is the case, or
> is it possible that Granite Rapids just uses a different access mechanism to
> provide the information ?
> 

This is the information I obtained by referring to the commit below. 
Of course, it would be best if Iwona could also help verify it.

https://github.com/ocp-hm-openbmc-opf-ami/linux/commit/94b4b0c83d33bec70dcc92f687c4a32e1a1e253c

> Thanks,
> Guenter
> 
> > 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@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);

Best Regards,
Changhuang