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Message-ID: <545fae8be782943a92d9df1c4a3ff90b7a865c76.camel@intel.com>
Date: Thu, 5 Jun 2025 02:18:07 +0000
From: "Zhang, Rui" <rui.zhang@...el.com>
To: "srinivas.pandruvada@...ux.intel.com"
<srinivas.pandruvada@...ux.intel.com>, "lukasz.luba@....com"
<lukasz.luba@....com>, "rafael@...nel.org" <rafael@...nel.org>,
"daniel.lezcano@...aro.org" <daniel.lezcano@...aro.org>
CC: "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] thermal: intel: int340x: Allow temperature override
On Wed, 2025-06-04 at 13:35 -0700, Srinivas Pandruvada wrote:
> Add debugfs interface to override hardware provide temperature. This
> interface can be used primarily for debug. Alternatively this can
> be also used to use hardware control loops to manage temperature for
> virtual sensors. Virtual sensors are soft sensors created by kernel/
> user space aggregating other sensors.
>
> There are three attributes to override the maximum three instances of
> platform temperature control.
> /sys/kernel/debug/plaftform_temperature_control/
> ├── temperature_0
> ├── temperature_1
> └── temperature_2
>
> These are write only attributes requires admin privilege. Any value
> greater than 0, will override the temperature. A value of 0 will
> stop overriding the temperature.
>
> Signed-off-by: Srinivas Pandruvada
> <srinivas.pandruvada@...ux.intel.com>
> ---
> .../platform_temperature_control.c | 64 +++++++++++++++++++
> 1 file changed, 64 insertions(+)
>
> diff --git
> a/drivers/thermal/intel/int340x_thermal/platform_temperature_control.c
> b/drivers/thermal/intel/int340x_thermal/platform_temperature_control.c
> index 6cd05783a52d..5dcfd2cc9082 100644
> ---
> a/drivers/thermal/intel/int340x_thermal/platform_temperature_control.c
> +++
> b/drivers/thermal/intel/int340x_thermal/platform_temperature_control.c
> @@ -38,6 +38,7 @@
>
> #include <linux/kernel.h>
> #include <linux/module.h>
> +#include <linux/debugfs.h>
> #include <linux/pci.h>
> #include "processor_thermal_device.h"
>
> @@ -53,6 +54,7 @@ struct mmio_reg {
>
> struct ptc_data {
> u32 offset;
> + struct pci_dev *pdev;
> struct attribute_group ptc_attr_group;
> struct attribute *ptc_attrs[PTC_MAX_ATTRS];
> struct device_attribute temperature_target_attr;
> @@ -222,6 +224,63 @@ static int ptc_create_groups(struct pci_dev *pdev,
> int instance, struct ptc_data
> }
>
> static struct ptc_data ptc_instance[PTC_MAX_INSTANCES];
> +static struct dentry *ptc_debugfs;
> +
> +#define PTC_TEMP_OVERRIDE_ENABLE_INDEX 4
> +#define PTC_TEMP_OVERRIDE_INDEX 5
> +
> +static ssize_t ptc_temperature_write(struct file *file, const char
> __user *data,
> + size_t count, loff_t *ppos)
> +{
> + struct ptc_data *ptc_instance = file->private_data;
> + struct pci_dev *pdev = ptc_instance->pdev;
> + char buf[32];
> + ssize_t len;
> + u32 value;
> +
> + len = min(count, sizeof(buf) - 1);
> + if (copy_from_user(buf, data, len))
> + return -EFAULT;
> +
> + buf[len] = '\0';
> + if (kstrtouint(buf, 0, &value))
> + return -EINVAL;
> +
> + if (ptc_mmio_regs[PTC_TEMP_OVERRIDE_INDEX].units)
> + value /= ptc_mmio_regs[PTC_TEMP_OVERRIDE_INDEX].units;
> +
> + if (value > ptc_mmio_regs[PTC_TEMP_OVERRIDE_INDEX].mask)
> + return -EINVAL;
> +
> + if (!value) {
> + ptc_mmio_write(pdev, ptc_instance->offset,
> PTC_TEMP_OVERRIDE_ENABLE_INDEX, 0);
> + } else {
> + ptc_mmio_write(pdev, ptc_instance->offset,
> PTC_TEMP_OVERRIDE_INDEX, value);
> + ptc_mmio_write(pdev, ptc_instance->offset,
> PTC_TEMP_OVERRIDE_ENABLE_INDEX, 1);
> + }
> +
> + return count;
> +}
> +
> +static const struct file_operations ptc_fops = {
> + .open = simple_open,
> + .write = ptc_temperature_write,
> + .llseek = generic_file_llseek,
> +};
> +
> +static void ptc_create_debugfs(void)
> +{
> + ptc_debugfs =
> debugfs_create_dir("plaftform_temperature_control", NULL);
s/platform/plaftform
And same in the changelog.
> +
> + debugfs_create_file("temperature_0", 0200, ptc_debugfs,
> &ptc_instance[0], &ptc_fops);
> + debugfs_create_file("temperature_1", 0200, ptc_debugfs,
> &ptc_instance[1], &ptc_fops);
> + debugfs_create_file("temperature_2", 0200, ptc_debugfs,
> &ptc_instance[2], &ptc_fops);
> +}
> +
> +static void ptc_delete_debugfs(void)
> +{
> + debugfs_remove_recursive(ptc_debugfs);
> +}
>
> int proc_thermal_ptc_add(struct pci_dev *pdev, struct
> proc_thermal_device *proc_priv)
> {
> @@ -230,10 +289,13 @@ int proc_thermal_ptc_add(struct pci_dev *pdev,
> struct proc_thermal_device *proc_
>
> for (i = 0; i < PTC_MAX_INSTANCES; i++) {
> ptc_instance[i].offset = ptc_offsets[i];
> + ptc_instance[i].pdev = pdev;
> ptc_create_groups(pdev, i, &ptc_instance[i]);
> }
> }
>
> + ptc_create_debugfs();
> +
should we create the debugfs only when PROC_THERMAL_FEATURE_PTC is set?
> return 0;
> }
> EXPORT_SYMBOL_GPL(proc_thermal_ptc_add);
> @@ -248,6 +310,8 @@ void proc_thermal_ptc_remove(struct pci_dev *pdev)
> for (i = 0; i < PTC_MAX_INSTANCES; i++)
> sysfs_remove_group(&pdev->dev.kobj,
> &ptc_instance[i].ptc_attr_group);
> }
> +
> + ptc_delete_debugfs();
ditto.
thanks,
rui
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