[PATCH 0/3] Platform Temperature Control interface

[PATCH 0/3] Platform Temperature Control interface

[Srinivas Pandruvada]

Platform Temperature Control is a dynamic control loop implemented in
hardware to manage the skin or any board temperature of a device. The
reported skin or board temperature is controlled by comparing to a
configured target temperature and adjusting the SoC (System on Chip)
performance accordingly.

This series supports optional controls from the user space.

Srinivas Pandruvada (3):
  thermal: intel: int340x: Add platform temperature control interface
  thermal: intel: int340x: Enable platform temperature control
  thermal: int340x: processor_thermal: Platform temperature control
    documentation

 .../driver-api/thermal/intel_dptf.rst         |  15 ++
 .../thermal/intel/int340x_thermal/Makefile    |   1 +
 .../platform_temperature_control.c            | 181 ++++++++++++++++++
 .../processor_thermal_device.c                |  15 +-
 .../processor_thermal_device.h                |   3 +
 .../processor_thermal_device_pci.c            |   6 +-
 6 files changed, 218 insertions(+), 3 deletions(-)
 create mode 100644 drivers/thermal/intel/int340x_thermal/platform_temperature_control.c

-- 
2.48.1

[PATCH 1/3] thermal: intel: int340x: Add platform temperature control interface

[Srinivas Pandruvada]

Platform Temperature Control is a dynamic control loop implemented in
hardware to manage the skin or any board temperature of a device. The
reported skin or board temperature is controlled by comparing to a
configured target temperature and adjusting the SoC (System on Chip)
performance accordingly. The feature supports up to three platform
sensors.

OEMs (Original Equipment Manufacturers) can configure this feature
through the BIOS and provide temperature input directly to the hardware
via the Platform Environment Control Interface (PECI). As a result,
this feature can operate independently of any OS-level control.

The OS interface can be used to further fine-tune the default OEM
configuration. Here are some scenarios where the OS interface is
beneficial:
Verification of Firmware Control: Check if firmware-based control is
enabled. If it is, thermal controls from the OS/user space can be
backed out.
Adjusting Target Limits: While OEMs can set an aggressive target limit,
the OS can adjust this to a less aggressive limit based on operating
modes or conditions.

The hardware control interface is via a MMIO offsets via processor
thermal device. There are three instances of MMIO registers. All
are 64 bit registers

Name: PLATFORM_TEMPERATURE_CONTROL
Offsets: 0x5B20, 0x5B28, 0x5B30

All values have RW access

Bits    Description
7:0     TARGET_TEMP : Target temperature limit to which the control
        mechanism is regulating. Units: 0.5C.
8:8     ENABLE: Read current enable status of the feature or enable
	feature.
11:9	GAIN: Sets the aggressiveness of control loop from 0 to 7
	7 graceful, favors performance at the expense of temperature
	overshoots
	0 aggressive, favors tight regulation over performance
12:12	TEMPERATURE_OVERRIDE_EN
	When set, hardware will use TEMPERATURE_OVERRIDE values instead
	of reading from corresponding sensor.
15:13	RESERVED
23:16	MIN_PERFORMANCE_LEVEL: Minimum Performance level below which the
	there will be no throttling. 0 - all levels of throttling allowed
	including survivability actions. 255 - no throttling allowed.
31:24	TEMPERATURE_OVERRIDE: Allows SW to override the input temperature.
	hardware will use this value instead of the sensor temperature.
	Units: 0.5C.
63:32	RESERVED

Out of the above controls, only "enable" and "temperature_target" is
exposed via sysfs.
There are three instances of this controls. So up to three different
sensors can be controlled independently.

Sysfs interface:
tree /sys/bus/pci/devices/0000\:00\:04.0/platform_temperature_?_control/
/sys/bus/pci/devices/0000:00:04.0/platform_temperature_0_control/
├── enable
├── temperature_target
/sys/bus/pci/devices/0000:00:04.0/platform_temperature_1_control/
├── enable
├── temperature_target
/sys/bus/pci/devices/0000:00:04.0/platform_temperature_2_control/
├── enable
├── temperature_target

Description of attributes:

Enable: 1 for enable, 0 for disable. This attribute can be used to
read the current status. User space can write 0 or 1 to disable or
enable this feature respectively.
temperature_target: Target temperature limit to which hardware
will try to limit in milli degree C.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 .../thermal/intel/int340x_thermal/Makefile    |   1 +
 .../platform_temperature_control.c            | 181 ++++++++++++++++++
 .../processor_thermal_device.c                |  15 +-
 .../processor_thermal_device.h                |   3 +
 4 files changed, 199 insertions(+), 1 deletion(-)
 create mode 100644 drivers/thermal/intel/int340x_thermal/platform_temperature_control.c

diff --git a/drivers/thermal/intel/int340x_thermal/Makefile b/drivers/thermal/intel/int340x_thermal/Makefile
index fe3f43924525..184318d1792b 100644
--- a/drivers/thermal/intel/int340x_thermal/Makefile
+++ b/drivers/thermal/intel/int340x_thermal/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_device_pci_legacy.o
 obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_device_pci.o
 obj-$(CONFIG_PROC_THERMAL_MMIO_RAPL) += processor_thermal_rapl.o
 obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_rfim.o
+obj-$(CONFIG_INT340X_THERMAL)	+= platform_temperature_control.o
 obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_mbox.o
 obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_wt_req.o
 obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_wt_hint.o
diff --git a/drivers/thermal/intel/int340x_thermal/platform_temperature_control.c b/drivers/thermal/intel/int340x_thermal/platform_temperature_control.c
new file mode 100644
index 000000000000..dd3ea7165800
--- /dev/null
+++ b/drivers/thermal/intel/int340x_thermal/platform_temperature_control.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * processor thermal device platform temperature controls
+ * Copyright (c) 2025, Intel Corporation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include "processor_thermal_device.h"
+
+struct mmio_reg {
+	int bits;
+	u16 mask;
+	u16 shift;
+	u16 units;
+};
+
+#define MAX_ATTR_GROUP_NAME_LEN 32
+
+struct ptc_data {
+	u32 offset;
+	struct attribute_group ptc_attr_group;
+	struct attribute *ptc_attrs[3];
+	struct device_attribute temperature_target_attr;
+	struct device_attribute enable_attr;
+	char group_name[MAX_ATTR_GROUP_NAME_LEN];
+};
+
+static const struct mmio_reg ptc_mmio_regs[] = {
+	{ 8, 0xFF, 0, 500}, /* temperature_target, units 0.5C*/
+	{ 1, 0x01, 8, 0}, /* enable */
+	{ 3, 0x7, 9, 0}, /* gain */
+	{ 8, 0xFF, 16, 0}, /* min_performance_level */
+	{ 1, 0x1, 12, 0}, /* temperature_override_enable */
+	{ 8, 0xFF, 24, 500}, /* temperature_override, units 0.5C */
+};
+
+/* Unique offset for each PTC instance */
+static u32 ptc_offsets[] = {0x5B20, 0x5B28, 0x5B30};
+
+/* These will represent sysfs attribute names */
+static const char * const ptc_strings[] = {
+	"temperature_target",
+	"enable",
+	NULL
+};
+
+#define PTC_SHOW(suffix)\
+static ssize_t suffix##_show(struct device *dev,\
+			     struct device_attribute *attr,\
+			     char *buf)\
+{\
+	struct ptc_data *data = container_of(attr, struct ptc_data, suffix##_attr);\
+	struct proc_thermal_device *proc_priv;\
+	struct pci_dev *pdev = to_pci_dev(dev);\
+	const struct mmio_reg *mmio_regs;\
+	int ret, units;\
+	u64 reg_val;\
+\
+	proc_priv = pci_get_drvdata(pdev);\
+	mmio_regs = ptc_mmio_regs;\
+	ret = match_string(ptc_strings, -1, attr->attr.name);\
+	if (ret < 0)\
+		return ret;\
+	units = mmio_regs[ret].units;\
+	reg_val = readq((void __iomem *) (proc_priv->mmio_base + data->offset));\
+	ret = (reg_val >> mmio_regs[ret].shift) & mmio_regs[ret].mask;\
+	if (units)\
+		ret *= units;\
+	return sysfs_emit(buf, "%d\n", ret);\
+}
+
+static void ptc_mmio_write(struct pci_dev *pdev, u32 offset, int index, u32 value)
+{
+	struct proc_thermal_device *proc_priv;
+	u64 mask, reg_val;
+
+	proc_priv = pci_get_drvdata(pdev);
+
+	mask = GENMASK(ptc_mmio_regs[index].shift + ptc_mmio_regs[index].bits - 1,
+		       ptc_mmio_regs[index].shift);
+	reg_val = readq((void __iomem *) (proc_priv->mmio_base + offset));
+	reg_val &= ~mask;
+	reg_val |= (value << ptc_mmio_regs[index].shift);
+	writeq(reg_val, (void __iomem *) (proc_priv->mmio_base + offset));
+}
+
+#define PTC_STORE(suffix)\
+static ssize_t suffix##_store(struct device *dev,\
+			      struct device_attribute *attr,\
+			      const char *buf, size_t count)\
+{\
+	struct ptc_data *data = container_of(attr, struct ptc_data, suffix##_attr);\
+	struct pci_dev *pdev = to_pci_dev(dev);\
+	unsigned int input;\
+	int ret;\
+\
+	ret = kstrtouint(buf, 10, &input);\
+	if (ret)\
+		return ret;\
+	ret = match_string(ptc_strings, -1, attr->attr.name);\
+	if (ret < 0)\
+		return ret;\
+	if (ptc_mmio_regs[ret].units)\
+		input /= ptc_mmio_regs[ret].units;\
+	if (input > ptc_mmio_regs[ret].mask)\
+		return -EINVAL;\
+	ptc_mmio_write(pdev, data->offset, ret, input);\
+	return count;\
+}
+
+PTC_SHOW(temperature_target);
+PTC_STORE(temperature_target);
+PTC_SHOW(enable);
+PTC_STORE(enable);
+
+#define ptc_init_attribute(_name)\
+	do {\
+		sysfs_attr_init(&data->_name##_attr.attr);\
+		data->_name##_attr.show = _name##_show;\
+		data->_name##_attr.store = _name##_store;\
+		data->_name##_attr.attr.name = #_name;\
+		data->_name##_attr.attr.mode = 0644;\
+	} while (0)
+
+static int ptc_create_groups(struct pci_dev *pdev, int instance, struct ptc_data *data)
+{
+	int ret, index = 0;
+
+	ptc_init_attribute(temperature_target);
+	ptc_init_attribute(enable);
+
+	data->ptc_attrs[index++] = &data->temperature_target_attr.attr;
+	data->ptc_attrs[index++] = &data->enable_attr.attr;
+	data->ptc_attrs[index] = NULL;
+
+	snprintf(data->group_name, MAX_ATTR_GROUP_NAME_LEN,
+		"platform_temperature_%d_control", instance);
+	data->ptc_attr_group.name = data->group_name;
+	data->ptc_attr_group.attrs = data->ptc_attrs;
+
+	ret = sysfs_create_group(&pdev->dev.kobj, &data->ptc_attr_group);
+
+	return ret;
+}
+
+#define PTC_MAX_INSTANCES	3
+static struct ptc_data ptc_instance[PTC_MAX_INSTANCES];
+
+int proc_thermal_ptc_add(struct pci_dev *pdev, struct proc_thermal_device *proc_priv)
+{
+	if (proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_PTC) {
+		int i;
+
+		for (i = 0; i < PTC_MAX_INSTANCES; i++) {
+			ptc_instance[i].offset = ptc_offsets[i];
+			ptc_create_groups(pdev, i, &ptc_instance[i]);
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(proc_thermal_ptc_add);
+
+void proc_thermal_ptc_remove(struct pci_dev *pdev)
+{
+	struct proc_thermal_device *proc_priv = pci_get_drvdata(pdev);
+
+	if (proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_PTC) {
+		int i;
+
+		for (i = 0; i < PTC_MAX_INSTANCES; i++)
+			sysfs_remove_group(&pdev->dev.kobj, &ptc_instance[i].ptc_attr_group);
+	}
+}
+EXPORT_SYMBOL_GPL(proc_thermal_ptc_remove);
+
+MODULE_IMPORT_NS("INT340X_THERMAL");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Processor Thermal PTC Interface");
diff --git a/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c b/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c
index c868d8b7bd1c..10841a37431c 100644
--- a/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c
+++ b/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c
@@ -399,13 +399,21 @@ int proc_thermal_mmio_add(struct pci_dev *pdev,
 		}
 	}
 
+	if (feature_mask & PROC_THERMAL_FEATURE_PTC) {
+		ret = proc_thermal_ptc_add(pdev, proc_priv);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to add PTC MMIO interface\n");
+			goto err_rem_rapl;
+		}
+	}
+
 	if (feature_mask & PROC_THERMAL_FEATURE_FIVR ||
 	    feature_mask & PROC_THERMAL_FEATURE_DVFS ||
 	    feature_mask & PROC_THERMAL_FEATURE_DLVR) {
 		ret = proc_thermal_rfim_add(pdev, proc_priv);
 		if (ret) {
 			dev_err(&pdev->dev, "failed to add RFIM interface\n");
-			goto err_rem_rapl;
+			goto err_rem_ptc;
 		}
 	}
 
@@ -427,6 +435,8 @@ int proc_thermal_mmio_add(struct pci_dev *pdev,
 
 err_rem_rfim:
 	proc_thermal_rfim_remove(pdev);
+err_rem_ptc:
+	proc_thermal_ptc_remove(pdev);
 err_rem_rapl:
 	proc_thermal_rapl_remove();
 
@@ -439,6 +449,9 @@ void proc_thermal_mmio_remove(struct pci_dev *pdev, struct proc_thermal_device *
 	if (proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_RAPL)
 		proc_thermal_rapl_remove();
 
+	if (proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_PTC)
+		proc_thermal_ptc_remove(pdev);
+
 	if (proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_FIVR ||
 	    proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_DVFS ||
 	    proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_DLVR)
diff --git a/drivers/thermal/intel/int340x_thermal/processor_thermal_device.h b/drivers/thermal/intel/int340x_thermal/processor_thermal_device.h
index ba2d89d3024c..9a6ca43b6fa2 100644
--- a/drivers/thermal/intel/int340x_thermal/processor_thermal_device.h
+++ b/drivers/thermal/intel/int340x_thermal/processor_thermal_device.h
@@ -67,6 +67,7 @@ struct rapl_mmio_regs {
 #define PROC_THERMAL_FEATURE_WT_HINT	0x20
 #define PROC_THERMAL_FEATURE_POWER_FLOOR	0x40
 #define PROC_THERMAL_FEATURE_MSI_SUPPORT	0x80
+#define PROC_THERMAL_FEATURE_PTC	0x100
 
 #if IS_ENABLED(CONFIG_PROC_THERMAL_MMIO_RAPL)
 int proc_thermal_rapl_add(struct pci_dev *pdev, struct proc_thermal_device *proc_priv);
@@ -123,4 +124,6 @@ int proc_thermal_mmio_add(struct pci_dev *pdev,
 			  struct proc_thermal_device *proc_priv,
 			  kernel_ulong_t feature_mask);
 void proc_thermal_mmio_remove(struct pci_dev *pdev, struct proc_thermal_device *proc_priv);
+int proc_thermal_ptc_add(struct pci_dev *pdev, struct proc_thermal_device *proc_priv);
+void proc_thermal_ptc_remove(struct pci_dev *pdev);
 #endif
-- 
2.48.1

Re: [PATCH 1/3] thermal: intel: int340x: Add platform temperature control interface

[Zhang, Rui]

On Sat, 2025-03-08 at 10:38 -0800, Srinivas Pandruvada wrote:
> Platform Temperature Control is a dynamic control loop implemented in
> hardware to manage the skin or any board temperature of a device. The
> reported skin or board temperature is controlled by comparing to a
> configured target temperature and adjusting the SoC (System on Chip)
> performance accordingly. The feature supports up to three platform
> sensors.
> 
> OEMs (Original Equipment Manufacturers) can configure this feature
> through the BIOS and provide temperature input directly to the
> hardware
> via the Platform Environment Control Interface (PECI).

Does this mean each PTC instance is bound to a certain skin/board
sensor? And writing the "temperature_target" sysfs tells firmware the
target temperature, as well as the target sensor that the temperature
applies to? if yes, is there a way for userspace to know which sensor
each PTC instance applies to?

>  As a result,
> this feature can operate independently of any OS-level control.
> 
> The OS interface can be used to further fine-tune the default OEM
> configuration. Here are some scenarios where the OS interface is
> beneficial:
> Verification of Firmware Control: Check if firmware-based control is
> enabled. If it is, thermal controls from the OS/user space can be
> backed out.
> Adjusting Target Limits: While OEMs can set an aggressive target
> limit,
> the OS can adjust this to a less aggressive limit based on operating
> modes or conditions.
> 
> The hardware control interface is via a MMIO offsets via processor
> thermal device. There are three instances of MMIO registers. All
> are 64 bit registers
> 
> Name: PLATFORM_TEMPERATURE_CONTROL
> Offsets: 0x5B20, 0x5B28, 0x5B30
> 
> All values have RW access
> 
> Bits    Description
> 7:0     TARGET_TEMP : Target temperature limit to which the control
>         mechanism is regulating. Units: 0.5C.
> 8:8     ENABLE: Read current enable status of the feature or enable
> 	feature.
> 11:9	GAIN: Sets the aggressiveness of control loop from 0 to 7
> 	7 graceful, favors performance at the expense of temperature
> 	overshoots
> 	0 aggressive, favors tight regulation over performance
> 12:12	TEMPERATURE_OVERRIDE_EN
> 	When set, hardware will use TEMPERATURE_OVERRIDE values
> instead
> 	of reading from corresponding sensor.
> 15:13	RESERVED
> 23:16	MIN_PERFORMANCE_LEVEL: Minimum Performance level below which
> the
> 	there will be no throttling. 0 - all levels of throttling
> allowed
> 	including survivability actions. 255 - no throttling
> allowed.
> 31:24	TEMPERATURE_OVERRIDE: Allows SW to override the input
> temperature.
> 	hardware will use this value instead of the sensor
> temperature.
> 	Units: 0.5C.
> 63:32	RESERVED
> 
> Out of the above controls, only "enable" and "temperature_target" is
> exposed via sysfs.
> There are three instances of this controls. So up to three different
> sensors can be controlled independently.
> 
> Sysfs interface:
> tree
> /sys/bus/pci/devices/0000\:00\:04.0/platform_temperature_?_control/
> /sys/bus/pci/devices/0000:00:04.0/platform_temperature_0_control/
> ├── enable
> ├── temperature_target
> /sys/bus/pci/devices/0000:00:04.0/platform_temperature_1_control/
> ├── enable
> ├── temperature_target
> /sys/bus/pci/devices/0000:00:04.0/platform_temperature_2_control/
> ├── enable
> ├── temperature_target
> 
> Description of attributes:
> 
> Enable: 1 for enable, 0 for disable. This attribute can be used to
> read the current status. User space can write 0 or 1 to disable or
> enable this feature respectively.
> temperature_target: Target temperature limit to which hardware
> will try to limit in milli degree C.
> 
> Signed-off-by: Srinivas Pandruvada
> <srinivas.pandruvada@linux.intel.com>
> ---
>  .../thermal/intel/int340x_thermal/Makefile    |   1 +
>  .../platform_temperature_control.c            | 181
> ++++++++++++++++++
>  .../processor_thermal_device.c                |  15 +-
>  .../processor_thermal_device.h                |   3 +
>  4 files changed, 199 insertions(+), 1 deletion(-)
>  create mode 100644
> drivers/thermal/intel/int340x_thermal/platform_temperature_control.c
> 
> diff --git a/drivers/thermal/intel/int340x_thermal/Makefile
> b/drivers/thermal/intel/int340x_thermal/Makefile
> index fe3f43924525..184318d1792b 100644
> --- a/drivers/thermal/intel/int340x_thermal/Makefile
> +++ b/drivers/thermal/intel/int340x_thermal/Makefile
> @@ -9,6 +9,7 @@ obj-$(CONFIG_INT340X_THERMAL)	+=
> processor_thermal_device_pci_legacy.o
>  obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_device_pci.o
>  obj-$(CONFIG_PROC_THERMAL_MMIO_RAPL) += processor_thermal_rapl.o
>  obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_rfim.o
> +obj-$(CONFIG_INT340X_THERMAL)	+= platform_temperature_control.o
>  obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_mbox.o
>  obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_wt_req.o
>  obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_wt_hint.o
> diff --git
> a/drivers/thermal/intel/int340x_thermal/platform_temperature_control.
> c
> b/drivers/thermal/intel/int340x_thermal/platform_temperature_control.
> c
> new file mode 100644
> index 000000000000..dd3ea7165800
> --- /dev/null
> +++
> b/drivers/thermal/intel/int340x_thermal/platform_temperature_control.
> c
> @@ -0,0 +1,181 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * processor thermal device platform temperature controls
> + * Copyright (c) 2025, Intel Corporation.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include "processor_thermal_device.h"
> +
> +struct mmio_reg {
> +	int bits;
> +	u16 mask;
> +	u16 shift;
> +	u16 units;
> +};
> +
> +#define MAX_ATTR_GROUP_NAME_LEN 32
> +
> +struct ptc_data {
> +	u32 offset;
> +	struct attribute_group ptc_attr_group;
> +	struct attribute *ptc_attrs[3];
> +	struct device_attribute temperature_target_attr;
> +	struct device_attribute enable_attr;
> +	char group_name[MAX_ATTR_GROUP_NAME_LEN];
> +};
> +
> +static const struct mmio_reg ptc_mmio_regs[] = {
> +	{ 8, 0xFF, 0, 500}, /* temperature_target, units 0.5C*/
> +	{ 1, 0x01, 8, 0}, /* enable */
> +	{ 3, 0x7, 9, 0}, /* gain */
> +	{ 8, 0xFF, 16, 0}, /* min_performance_level */
> +	{ 1, 0x1, 12, 0}, /* temperature_override_enable */
> +	{ 8, 0xFF, 24, 500}, /* temperature_override, units 0.5C */
> +};
> +
> +/* Unique offset for each PTC instance */
> +static u32 ptc_offsets[] = {0x5B20, 0x5B28, 0x5B30};

I'd prefer to define PTC_MAX_INSTANCES earlier and use
  static u32 ptc_offsets[PTC_MAX_INSTANCES] = {0x5B20, 0x5B28, 0x5B30};
instead.

thanks,
rui

Re: [PATCH 1/3] thermal: intel: int340x: Add platform temperature control interface

[srinivas pandruvada]

On Tue, 2025-03-11 at 05:56 +0000, Zhang, Rui wrote:
> On Sat, 2025-03-08 at 10:38 -0800, Srinivas Pandruvada wrote:
> > Platform Temperature Control is a dynamic control loop implemented
> > in
> > hardware to manage the skin or any board temperature of a device.
> > The
> > reported skin or board temperature is controlled by comparing to a
> > configured target temperature and adjusting the SoC (System on
> > Chip)
> > performance accordingly. The feature supports up to three platform
> > sensors.
> > 
> > OEMs (Original Equipment Manufacturers) can configure this feature
> > through the BIOS and provide temperature input directly to the
> > hardware
> > via the Platform Environment Control Interface (PECI).
> 
> Does this mean each PTC instance is bound to a certain skin/board
> sensor?
Yes.

>  And writing the "temperature_target" sysfs tells firmware the
> target temperature, as well as the target sensor that the temperature
> applies to? 
Yes

> if yes, is there a way for userspace to know which sensor
> each PTC instance applies to?
No.
You can just change threshold up and down by observation only.

Thanks,
Srinivas

> 
> >  As a result,
> > this feature can operate independently of any OS-level control.
> > 
> > The OS interface can be used to further fine-tune the default OEM
> > configuration. Here are some scenarios where the OS interface is
> > beneficial:
> > Verification of Firmware Control: Check if firmware-based control
> > is
> > enabled. If it is, thermal controls from the OS/user space can be
> > backed out.
> > Adjusting Target Limits: While OEMs can set an aggressive target
> > limit,
> > the OS can adjust this to a less aggressive limit based on
> > operating
> > modes or conditions.
> > 
> > The hardware control interface is via a MMIO offsets via processor
> > thermal device. There are three instances of MMIO registers. All
> > are 64 bit registers
> > 
> > Name: PLATFORM_TEMPERATURE_CONTROL
> > Offsets: 0x5B20, 0x5B28, 0x5B30
> > 
> > All values have RW access
> > 
> > Bits    Description
> > 7:0     TARGET_TEMP : Target temperature limit to which the control
> >         mechanism is regulating. Units: 0.5C.
> > 8:8     ENABLE: Read current enable status of the feature or enable
> > 	feature.
> > 11:9	GAIN: Sets the aggressiveness of control loop from 0 to 7
> > 	7 graceful, favors performance at the expense of
> > temperature
> > 	overshoots
> > 	0 aggressive, favors tight regulation over performance
> > 12:12	TEMPERATURE_OVERRIDE_EN
> > 	When set, hardware will use TEMPERATURE_OVERRIDE values
> > instead
> > 	of reading from corresponding sensor.
> > 15:13	RESERVED
> > 23:16	MIN_PERFORMANCE_LEVEL: Minimum Performance level below
> > which
> > the
> > 	there will be no throttling. 0 - all levels of throttling
> > allowed
> > 	including survivability actions. 255 - no throttling
> > allowed.
> > 31:24	TEMPERATURE_OVERRIDE: Allows SW to override the input
> > temperature.
> > 	hardware will use this value instead of the sensor
> > temperature.
> > 	Units: 0.5C.
> > 63:32	RESERVED
> > 
> > Out of the above controls, only "enable" and "temperature_target"
> > is
> > exposed via sysfs.
> > There are three instances of this controls. So up to three
> > different
> > sensors can be controlled independently.
> > 
> > Sysfs interface:
> > tree
> > /sys/bus/pci/devices/0000\:00\:04.0/platform_temperature_?_control/
> > /sys/bus/pci/devices/0000:00:04.0/platform_temperature_0_control/
> > ├── enable
> > ├── temperature_target
> > /sys/bus/pci/devices/0000:00:04.0/platform_temperature_1_control/
> > ├── enable
> > ├── temperature_target
> > /sys/bus/pci/devices/0000:00:04.0/platform_temperature_2_control/
> > ├── enable
> > ├── temperature_target
> > 
> > Description of attributes:
> > 
> > Enable: 1 for enable, 0 for disable. This attribute can be used to
> > read the current status. User space can write 0 or 1 to disable or
> > enable this feature respectively.
> > temperature_target: Target temperature limit to which hardware
> > will try to limit in milli degree C.
> > 
> > Signed-off-by: Srinivas Pandruvada
> > <srinivas.pandruvada@linux.intel.com>
> > ---
> >  .../thermal/intel/int340x_thermal/Makefile    |   1 +
> >  .../platform_temperature_control.c            | 181
> > ++++++++++++++++++
> >  .../processor_thermal_device.c                |  15 +-
> >  .../processor_thermal_device.h                |   3 +
> >  4 files changed, 199 insertions(+), 1 deletion(-)
> >  create mode 100644
> > drivers/thermal/intel/int340x_thermal/platform_temperature_control.
> > c
> > 
> > diff --git a/drivers/thermal/intel/int340x_thermal/Makefile
> > b/drivers/thermal/intel/int340x_thermal/Makefile
> > index fe3f43924525..184318d1792b 100644
> > --- a/drivers/thermal/intel/int340x_thermal/Makefile
> > +++ b/drivers/thermal/intel/int340x_thermal/Makefile
> > @@ -9,6 +9,7 @@ obj-$(CONFIG_INT340X_THERMAL)	+=
> > processor_thermal_device_pci_legacy.o
> >  obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_device_pci.o
> >  obj-$(CONFIG_PROC_THERMAL_MMIO_RAPL) += processor_thermal_rapl.o
> >  obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_rfim.o
> > +obj-$(CONFIG_INT340X_THERMAL)	+= platform_temperature_control.o
> >  obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_mbox.o
> >  obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_wt_req.o
> >  obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_wt_hint.o
> > diff --git
> > a/drivers/thermal/intel/int340x_thermal/platform_temperature_contro
> > l.
> > c
> > b/drivers/thermal/intel/int340x_thermal/platform_temperature_contro
> > l.
> > c
> > new file mode 100644
> > index 000000000000..dd3ea7165800
> > --- /dev/null
> > +++
> > b/drivers/thermal/intel/int340x_thermal/platform_temperature_contro
> > l.
> > c
> > @@ -0,0 +1,181 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * processor thermal device platform temperature controls
> > + * Copyright (c) 2025, Intel Corporation.
> > + */
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/pci.h>
> > +#include "processor_thermal_device.h"
> > +
> > +struct mmio_reg {
> > +	int bits;
> > +	u16 mask;
> > +	u16 shift;
> > +	u16 units;
> > +};
> > +
> > +#define MAX_ATTR_GROUP_NAME_LEN 32
> > +
> > +struct ptc_data {
> > +	u32 offset;
> > +	struct attribute_group ptc_attr_group;
> > +	struct attribute *ptc_attrs[3];
> > +	struct device_attribute temperature_target_attr;
> > +	struct device_attribute enable_attr;
> > +	char group_name[MAX_ATTR_GROUP_NAME_LEN];
> > +};
> > +
> > +static const struct mmio_reg ptc_mmio_regs[] = {
> > +	{ 8, 0xFF, 0, 500}, /* temperature_target, units 0.5C*/
> > +	{ 1, 0x01, 8, 0}, /* enable */
> > +	{ 3, 0x7, 9, 0}, /* gain */
> > +	{ 8, 0xFF, 16, 0}, /* min_performance_level */
> > +	{ 1, 0x1, 12, 0}, /* temperature_override_enable */
> > +	{ 8, 0xFF, 24, 500}, /* temperature_override, units 0.5C
> > */
> > +};
> > +
> > +/* Unique offset for each PTC instance */
> > +static u32 ptc_offsets[] = {0x5B20, 0x5B28, 0x5B30};
> 
> I'd prefer to define PTC_MAX_INSTANCES earlier and use
>   static u32 ptc_offsets[PTC_MAX_INSTANCES] = {0x5B20, 0x5B28,
> 0x5B30};
> instead.
> 
> thanks,
> rui

[PATCH 2/3] thermal: intel: int340x: Enable platform temperature control

[Srinivas Pandruvada]

Enable platform temperature control feature for Lunar Lake and
Panther Lake.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 .../intel/int340x_thermal/processor_thermal_device_pci.c    | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/thermal/intel/int340x_thermal/processor_thermal_device_pci.c b/drivers/thermal/intel/int340x_thermal/processor_thermal_device_pci.c
index a55aaa8cef42..f7f03159606a 100644
--- a/drivers/thermal/intel/int340x_thermal/processor_thermal_device_pci.c
+++ b/drivers/thermal/intel/int340x_thermal/processor_thermal_device_pci.c
@@ -486,7 +486,8 @@ static const struct pci_device_id proc_thermal_pci_ids[] = {
 	  PROC_THERMAL_FEATURE_FIVR | PROC_THERMAL_FEATURE_DVFS | PROC_THERMAL_FEATURE_WT_REQ) },
 	{ PCI_DEVICE_DATA(INTEL, LNLM_THERMAL, PROC_THERMAL_FEATURE_MSI_SUPPORT |
 	  PROC_THERMAL_FEATURE_RAPL | PROC_THERMAL_FEATURE_DLVR |
-	  PROC_THERMAL_FEATURE_WT_HINT | PROC_THERMAL_FEATURE_POWER_FLOOR) },
+	  PROC_THERMAL_FEATURE_WT_HINT | PROC_THERMAL_FEATURE_POWER_FLOOR |
+	  PROC_THERMAL_FEATURE_PTC) },
 	{ PCI_DEVICE_DATA(INTEL, MTLP_THERMAL, PROC_THERMAL_FEATURE_RAPL |
 	  PROC_THERMAL_FEATURE_FIVR | PROC_THERMAL_FEATURE_DVFS | PROC_THERMAL_FEATURE_DLVR |
 	  PROC_THERMAL_FEATURE_WT_HINT | PROC_THERMAL_FEATURE_POWER_FLOOR) },
@@ -496,7 +497,8 @@ static const struct pci_device_id proc_thermal_pci_ids[] = {
 	  PROC_THERMAL_FEATURE_FIVR | PROC_THERMAL_FEATURE_DVFS | PROC_THERMAL_FEATURE_WT_REQ) },
 	{ PCI_DEVICE_DATA(INTEL, PTL_THERMAL, PROC_THERMAL_FEATURE_RAPL |
 	  PROC_THERMAL_FEATURE_DLVR | PROC_THERMAL_FEATURE_MSI_SUPPORT |
-	  PROC_THERMAL_FEATURE_WT_HINT | PROC_THERMAL_FEATURE_POWER_FLOOR) },
+	  PROC_THERMAL_FEATURE_WT_HINT | PROC_THERMAL_FEATURE_POWER_FLOOR |
+	  PROC_THERMAL_FEATURE_PTC) },
 	{ },
 };
 
-- 
2.48.1

[PATCH 3/3] thermal: int340x: processor_thermal: Platform temperature control documentation

[Srinivas Pandruvada]

Update documentation of attributes for platform temperature control.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 Documentation/driver-api/thermal/intel_dptf.rst | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/driver-api/thermal/intel_dptf.rst b/Documentation/driver-api/thermal/intel_dptf.rst
index 8fb8c5b2d685..e7e387d60b7e 100644
--- a/Documentation/driver-api/thermal/intel_dptf.rst
+++ b/Documentation/driver-api/thermal/intel_dptf.rst
@@ -191,6 +191,21 @@ ABI.
 	User space can specify any one of the available workload type using
 	this interface.
 
+:file:`/sys/bus/pci/devices/0000\:00\:04.0/platform_temperature_0_control`
+:file:`/sys/bus/pci/devices/0000\:00\:04.0/platform_temperature_1_control`
+:file:`/sys/bus/pci/devices/0000\:00\:04.0/platform_temperature_2_control`
+
+All these controls needs admin privilege to update.
+
+``enable`` (RW)
+	1 for enable, 0 for disable. Shows the current enable status of
+	platform temperature control feature. User space can enable/disable
+	hardware controls.
+
+``temperature_target`` (RW)
+	Update a new temperature target in milli degree celsius for hardware to
+	use for the temperature control.
+
 DPTF Processor thermal RFIM interface
 --------------------------------------------
 
-- 
2.48.1

Re: [PATCH 0/3] Platform Temperature Control interface

[srinivas pandruvada]

On Sat, 2025-03-08 at 10:38 -0800, Srinivas Pandruvada wrote:
> Platform Temperature Control is a dynamic control loop implemented in
> hardware to manage the skin or any board temperature of a device. The
> reported skin or board temperature is controlled by comparing to a
> configured target temperature and adjusting the SoC (System on Chip)
> performance accordingly.
> 
> This series supports optional controls from the user space.
> 
Missed cc to linux-pm@vger.kernel.org to resent again.

Thanks,
Srinivas

> Srinivas Pandruvada (3):
>   thermal: intel: int340x: Add platform temperature control interface
>   thermal: intel: int340x: Enable platform temperature control
>   thermal: int340x: processor_thermal: Platform temperature control
>     documentation
> 
>  .../driver-api/thermal/intel_dptf.rst         |  15 ++
>  .../thermal/intel/int340x_thermal/Makefile    |   1 +
>  .../platform_temperature_control.c            | 181
> ++++++++++++++++++
>  .../processor_thermal_device.c                |  15 +-
>  .../processor_thermal_device.h                |   3 +
>  .../processor_thermal_device_pci.c            |   6 +-
>  6 files changed, 218 insertions(+), 3 deletions(-)
>  create mode 100644
> drivers/thermal/intel/int340x_thermal/platform_temperature_control.c
>