drivers/acpi/processor_thermal.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * processor_thermal.c - Passive cooling submodule of the ACPI processor driver
  *
  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
  *  			- Added processor hotplug support
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/cpufreq.h>
 #include <linux/acpi.h>
 #include <acpi/processor.h>
 #include <linux/uaccess.h>

 #include "internal.h"

 #ifdef CONFIG_CPU_FREQ

 /* If a passive cooling situation is detected, primarily CPUfreq is used, as it
  * offers (in most cases) voltage scaling in addition to frequency scaling, and
  * thus a cubic (instead of linear) reduction of energy. Also, we allow for
  * _any_ cpufreq driver and not only the acpi-cpufreq driver.
  */

 #define CPUFREQ_THERMAL_MIN_STEP 0

 static int cpufreq_thermal_max_step __read_mostly = 3;

 /*
  * Minimum throttle percentage for processor_thermal cooling device.
  * The processor_thermal driver uses it to calculate the percentage amount by
  * which cpu frequency must be reduced for each cooling state. This is also used
  * to calculate the maximum number of throttling steps or cooling states.
  */
 static int cpufreq_thermal_reduction_pctg __read_mostly = 20;

 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_step);

 #define reduction_step(cpu) \
 	per_cpu(cpufreq_thermal_reduction_step, phys_package_first_cpu(cpu))

 /*
  * Emulate "per package data" using per cpu data (which should really be
  * provided elsewhere)
  *
  * Note we can lose a CPU on cpu hotunplug, in this case we forget the state
  * temporarily. Fortunately that's not a big issue here (I hope)
  */
 static int phys_package_first_cpu(int cpu)
 {
 	int i;
 	int id = topology_physical_package_id(cpu);

 	for_each_online_cpu(i)
 		if (topology_physical_package_id(i) == id)
 			return i;
 	return 0;
 }

 static int cpu_has_cpufreq(unsigned int cpu)
 {
 	struct cpufreq_policy *policy;

 	if (!acpi_processor_cpufreq_init)
 		return 0;

 	policy = cpufreq_cpu_get(cpu);
 	if (policy) {
 		cpufreq_cpu_put(policy);
 		return 1;
 	}
 	return 0;
 }

 static int cpufreq_get_max_state(unsigned int cpu)
 {
 	if (!cpu_has_cpufreq(cpu))
 		return 0;

 	return cpufreq_thermal_max_step;
 }

 static int cpufreq_get_cur_state(unsigned int cpu)
 {
 	if (!cpu_has_cpufreq(cpu))
 		return 0;

 	return reduction_step(cpu);
 }

 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 {
 	struct cpufreq_policy *policy;
 	struct acpi_processor *pr;
 	unsigned long max_freq;
 	int i, ret;

 	if (!cpu_has_cpufreq(cpu))
 		return 0;

 	reduction_step(cpu) = state;

 	/*
 	 * Update all the CPUs in the same package because they all
 	 * contribute to the temperature and often share the same
 	 * frequency.
 	 */
 	for_each_online_cpu(i) {
 		if (topology_physical_package_id(i) !=
 		    topology_physical_package_id(cpu))
 			continue;

 		pr = per_cpu(processors, i);

 		if (unlikely(!freq_qos_request_active(&pr->thermal_req)))
 			continue;

 		policy = cpufreq_cpu_get(i);
 		if (!policy)
 			return -EINVAL;

 		max_freq = (policy->cpuinfo.max_freq *
 			    (100 - reduction_step(i) * cpufreq_thermal_reduction_pctg)) / 100;

 		cpufreq_cpu_put(policy);

 		ret = freq_qos_update_request(&pr->thermal_req, max_freq);
 		if (ret < 0) {
 			pr_warn("Failed to update thermal freq constraint: CPU%d (%d)\n",
 				pr->id, ret);
 		}
 	}
 	return 0;
 }

 static void acpi_thermal_cpufreq_config(void)
 {
 	int cpufreq_pctg = acpi_arch_thermal_cpufreq_pctg();

 	if (!cpufreq_pctg)
 		return;

 	cpufreq_thermal_reduction_pctg = cpufreq_pctg;

 	/*
 	 * Derive the MAX_STEP from minimum throttle percentage so that the reduction
 	 * percentage doesn't end up becoming negative. Also, cap the MAX_STEP so that
 	 * the CPU performance doesn't become 0.
 	 */
 	cpufreq_thermal_max_step = (100 / cpufreq_pctg) - 2;
 }

 void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy)
 {
 	unsigned int cpu;

 	acpi_thermal_cpufreq_config();

 	for_each_cpu(cpu, policy->related_cpus) {
 		struct acpi_processor *pr = per_cpu(processors, cpu);
 		int ret;

 		if (!pr)
 			continue;

 		ret = freq_qos_add_request(&policy->constraints,
 					   &pr->thermal_req,
 					   FREQ_QOS_MAX, INT_MAX);
 		if (ret < 0) {
 			pr_err("Failed to add freq constraint for CPU%d (%d)\n",
 			       cpu, ret);
 			continue;
 		}

 		thermal_cooling_device_update(pr->cdev);
 	}
 }

 void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
 {
 	unsigned int cpu;

 	for_each_cpu(cpu, policy->related_cpus) {
 		struct acpi_processor *pr = per_cpu(processors, cpu);

 		if (!pr)
 			continue;

 		freq_qos_remove_request(&pr->thermal_req);

 		thermal_cooling_device_update(pr->cdev);
 	}
 }
 #else				/* ! CONFIG_CPU_FREQ */
 static int cpufreq_get_max_state(unsigned int cpu)
 {
 	return 0;
 }

 static int cpufreq_get_cur_state(unsigned int cpu)
 {
 	return 0;
 }

 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 {
 	return 0;
 }

 #endif

 /* thermal cooling device callbacks */
 static int acpi_processor_max_state(struct acpi_processor *pr)
 {
 	int max_state = 0;

 	/*
 	 * There exists four states according to
 	 * cpufreq_thermal_reduction_step. 0, 1, 2, 3
 	 */
 	max_state += cpufreq_get_max_state(pr->id);
 	if (pr->flags.throttling)
 		max_state += (pr->throttling.state_count -1);

 	return max_state;
 }
 static int
 processor_get_max_state(struct thermal_cooling_device *cdev,
 			unsigned long *state)
 {
 	struct acpi_device *device = cdev->devdata;
 	struct acpi_processor *pr;

 	if (!device)
 		return -EINVAL;

 	pr = acpi_driver_data(device);
 	if (!pr)
 		return -EINVAL;

 	*state = acpi_processor_max_state(pr);
 	return 0;
 }

 static int
 processor_get_cur_state(struct thermal_cooling_device *cdev,
 			unsigned long *cur_state)
 {
 	struct acpi_device *device = cdev->devdata;
 	struct acpi_processor *pr;

 	if (!device)
 		return -EINVAL;

 	pr = acpi_driver_data(device);
 	if (!pr)
 		return -EINVAL;

 	*cur_state = cpufreq_get_cur_state(pr->id);
 	if (pr->flags.throttling)
 		*cur_state += pr->throttling.state;
 	return 0;
 }

 static int
 processor_set_cur_state(struct thermal_cooling_device *cdev,
 			unsigned long state)
 {
 	struct acpi_device *device = cdev->devdata;
 	struct acpi_processor *pr;
 	int result = 0;
 	int max_pstate;

 	if (!device)
 		return -EINVAL;

 	pr = acpi_driver_data(device);
 	if (!pr)
 		return -EINVAL;

 	max_pstate = cpufreq_get_max_state(pr->id);

 	if (state > acpi_processor_max_state(pr))
 		return -EINVAL;

 	if (state <= max_pstate) {
 		if (pr->flags.throttling && pr->throttling.state)
 			result = acpi_processor_set_throttling(pr, 0, false);
 		cpufreq_set_cur_state(pr->id, state);
 	} else {
 		cpufreq_set_cur_state(pr->id, max_pstate);
 		result = acpi_processor_set_throttling(pr,
 				state - max_pstate, false);
 	}
 	return result;
 }

 const struct thermal_cooling_device_ops processor_cooling_ops = {
 	.get_max_state = processor_get_max_state,
 	.get_cur_state = processor_get_cur_state,
 	.set_cur_state = processor_set_cur_state,
 };

 int acpi_processor_thermal_init(struct acpi_processor *pr,
 				struct acpi_device *device)
 {
 	int result = 0;

 	pr->cdev = thermal_cooling_device_register("Processor", device,
 						   &processor_cooling_ops);
 	if (IS_ERR(pr->cdev)) {
 		result = PTR_ERR(pr->cdev);
 		return result;
 	}

 	dev_dbg(&device->dev, "registered as cooling_device%d\n",
 		pr->cdev->id);

 	result = sysfs_create_link(&device->dev.kobj,
 				   &pr->cdev->device.kobj,
 				   "thermal_cooling");
 	if (result) {
 		dev_err(&device->dev,
 			"Failed to create sysfs link 'thermal_cooling'\n");
 		goto err_thermal_unregister;
 	}

 	result = sysfs_create_link(&pr->cdev->device.kobj,
 				   &device->dev.kobj,
 				   "device");
 	if (result) {
 		dev_err(&pr->cdev->device,
 			"Failed to create sysfs link 'device'\n");
 		goto err_remove_sysfs_thermal;
 	}

 	return 0;

 err_remove_sysfs_thermal:
 	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
 err_thermal_unregister:
 	thermal_cooling_device_unregister(pr->cdev);

 	return result;
 }

 void acpi_processor_thermal_exit(struct acpi_processor *pr,
 				 struct acpi_device *device)
 {
 	if (pr->cdev) {
 		sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
 		sysfs_remove_link(&pr->cdev->device.kobj, "device");
 		thermal_cooling_device_unregister(pr->cdev);
 		pr->cdev = NULL;
 	}
 }
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* processor_thermal.c - Passive cooling submodule of the ACPI processor driver
	*
	* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
	* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
	* Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>
	* Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
	* - Added processor hotplug support
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/cpufreq.h>
	#include <linux/acpi.h>
	#include <acpi/processor.h>
	#include <linux/uaccess.h>

	#include "internal.h"

	#ifdef CONFIG_CPU_FREQ

	/* If a passive cooling situation is detected, primarily CPUfreq is used, as it
	* offers (in most cases) voltage scaling in addition to frequency scaling, and
	* thus a cubic (instead of linear) reduction of energy. Also, we allow for
	* _any_ cpufreq driver and not only the acpi-cpufreq driver.
	*/

	#define CPUFREQ_THERMAL_MIN_STEP 0

	static int cpufreq_thermal_max_step __read_mostly = 3;

	/*
	* Minimum throttle percentage for processor_thermal cooling device.
	* The processor_thermal driver uses it to calculate the percentage amount by
	* which cpu frequency must be reduced for each cooling state. This is also used
	* to calculate the maximum number of throttling steps or cooling states.
	*/
	static int cpufreq_thermal_reduction_pctg __read_mostly = 20;

	static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_step);

	#define reduction_step(cpu) \
	per_cpu(cpufreq_thermal_reduction_step, phys_package_first_cpu(cpu))

	/*
	* Emulate "per package data" using per cpu data (which should really be
	* provided elsewhere)
	*
	* Note we can lose a CPU on cpu hotunplug, in this case we forget the state
	* temporarily. Fortunately that's not a big issue here (I hope)
	*/
	static int phys_package_first_cpu(int cpu)
	{
	int i;
	int id = topology_physical_package_id(cpu);

	for_each_online_cpu(i)
	if (topology_physical_package_id(i) == id)
	return i;
	return 0;
	}

	static int cpu_has_cpufreq(unsigned int cpu)
	{
	struct cpufreq_policy *policy;

	if (!acpi_processor_cpufreq_init)
	return 0;

	policy = cpufreq_cpu_get(cpu);
	if (policy) {
	cpufreq_cpu_put(policy);
	return 1;
	}
	return 0;
	}

	static int cpufreq_get_max_state(unsigned int cpu)
	{
	if (!cpu_has_cpufreq(cpu))
	return 0;

	return cpufreq_thermal_max_step;
	}

	static int cpufreq_get_cur_state(unsigned int cpu)
	{
	if (!cpu_has_cpufreq(cpu))
	return 0;

	return reduction_step(cpu);
	}

	static int cpufreq_set_cur_state(unsigned int cpu, int state)
	{
	struct cpufreq_policy *policy;
	struct acpi_processor *pr;
	unsigned long max_freq;
	int i, ret;

	if (!cpu_has_cpufreq(cpu))
	return 0;

	reduction_step(cpu) = state;

	/*
	* Update all the CPUs in the same package because they all
	* contribute to the temperature and often share the same
	* frequency.
	*/
	for_each_online_cpu(i) {
	if (topology_physical_package_id(i) !=
	topology_physical_package_id(cpu))
	continue;

	pr = per_cpu(processors, i);

	if (unlikely(!freq_qos_request_active(&pr->thermal_req)))
	continue;

	policy = cpufreq_cpu_get(i);
	if (!policy)
	return -EINVAL;

	max_freq = (policy->cpuinfo.max_freq *
	(100 - reduction_step(i) * cpufreq_thermal_reduction_pctg)) / 100;

	cpufreq_cpu_put(policy);

	ret = freq_qos_update_request(&pr->thermal_req, max_freq);
	if (ret < 0) {
	pr_warn("Failed to update thermal freq constraint: CPU%d (%d)\n",
	pr->id, ret);
	}
	}
	return 0;
	}

	static void acpi_thermal_cpufreq_config(void)
	{
	int cpufreq_pctg = acpi_arch_thermal_cpufreq_pctg();

	if (!cpufreq_pctg)
	return;

	cpufreq_thermal_reduction_pctg = cpufreq_pctg;

	/*
	* Derive the MAX_STEP from minimum throttle percentage so that the reduction
	* percentage doesn't end up becoming negative. Also, cap the MAX_STEP so that
	* the CPU performance doesn't become 0.
	*/
	cpufreq_thermal_max_step = (100 / cpufreq_pctg) - 2;
	}

	void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy)
	{
	unsigned int cpu;

	acpi_thermal_cpufreq_config();

	for_each_cpu(cpu, policy->related_cpus) {
	struct acpi_processor *pr = per_cpu(processors, cpu);
	int ret;

	if (!pr)
	continue;

	ret = freq_qos_add_request(&policy->constraints,
	&pr->thermal_req,
	FREQ_QOS_MAX, INT_MAX);
	if (ret < 0) {
	pr_err("Failed to add freq constraint for CPU%d (%d)\n",
	cpu, ret);
	continue;
	}

	thermal_cooling_device_update(pr->cdev);
	}
	}

	void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
	{
	unsigned int cpu;

	for_each_cpu(cpu, policy->related_cpus) {
	struct acpi_processor *pr = per_cpu(processors, cpu);

	if (!pr)
	continue;

	freq_qos_remove_request(&pr->thermal_req);

	thermal_cooling_device_update(pr->cdev);
	}
	}
	#else /* ! CONFIG_CPU_FREQ */
	static int cpufreq_get_max_state(unsigned int cpu)
	{
	return 0;
	}

	static int cpufreq_get_cur_state(unsigned int cpu)
	{
	return 0;
	}

	static int cpufreq_set_cur_state(unsigned int cpu, int state)
	{
	return 0;
	}

	#endif

	/* thermal cooling device callbacks */
	static int acpi_processor_max_state(struct acpi_processor *pr)
	{
	int max_state = 0;

	/*
	* There exists four states according to
	* cpufreq_thermal_reduction_step. 0, 1, 2, 3
	*/
	max_state += cpufreq_get_max_state(pr->id);
	if (pr->flags.throttling)
	max_state += (pr->throttling.state_count -1);

	return max_state;
	}
	static int
	processor_get_max_state(struct thermal_cooling_device *cdev,
	unsigned long *state)
	{
	struct acpi_device *device = cdev->devdata;
	struct acpi_processor *pr;

	if (!device)
	return -EINVAL;

	pr = acpi_driver_data(device);
	if (!pr)
	return -EINVAL;

	*state = acpi_processor_max_state(pr);
	return 0;
	}

	static int
	processor_get_cur_state(struct thermal_cooling_device *cdev,
	unsigned long *cur_state)
	{
	struct acpi_device *device = cdev->devdata;
	struct acpi_processor *pr;

	if (!device)
	return -EINVAL;

	pr = acpi_driver_data(device);
	if (!pr)
	return -EINVAL;

	*cur_state = cpufreq_get_cur_state(pr->id);
	if (pr->flags.throttling)
	*cur_state += pr->throttling.state;
	return 0;
	}

	static int
	processor_set_cur_state(struct thermal_cooling_device *cdev,
	unsigned long state)
	{
	struct acpi_device *device = cdev->devdata;
	struct acpi_processor *pr;
	int result = 0;
	int max_pstate;

	if (!device)
	return -EINVAL;

	pr = acpi_driver_data(device);
	if (!pr)
	return -EINVAL;

	max_pstate = cpufreq_get_max_state(pr->id);

	if (state > acpi_processor_max_state(pr))
	return -EINVAL;

	if (state <= max_pstate) {
	if (pr->flags.throttling && pr->throttling.state)
	result = acpi_processor_set_throttling(pr, 0, false);
	cpufreq_set_cur_state(pr->id, state);
	} else {
	cpufreq_set_cur_state(pr->id, max_pstate);
	result = acpi_processor_set_throttling(pr,
	state - max_pstate, false);
	}
	return result;
	}

	const struct thermal_cooling_device_ops processor_cooling_ops = {
	.get_max_state = processor_get_max_state,
	.get_cur_state = processor_get_cur_state,
	.set_cur_state = processor_set_cur_state,
	};

	int acpi_processor_thermal_init(struct acpi_processor *pr,
	struct acpi_device *device)
	{
	int result = 0;

	pr->cdev = thermal_cooling_device_register("Processor", device,
	&processor_cooling_ops);
	if (IS_ERR(pr->cdev)) {
	result = PTR_ERR(pr->cdev);
	return result;
	}

	dev_dbg(&device->dev, "registered as cooling_device%d\n",
	pr->cdev->id);

	result = sysfs_create_link(&device->dev.kobj,
	&pr->cdev->device.kobj,
	"thermal_cooling");
	if (result) {
	dev_err(&device->dev,
	"Failed to create sysfs link 'thermal_cooling'\n");
	goto err_thermal_unregister;
	}

	result = sysfs_create_link(&pr->cdev->device.kobj,
	&device->dev.kobj,
	"device");
	if (result) {
	dev_err(&pr->cdev->device,
	"Failed to create sysfs link 'device'\n");
	goto err_remove_sysfs_thermal;
	}

	return 0;

	err_remove_sysfs_thermal:
	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
	err_thermal_unregister:
	thermal_cooling_device_unregister(pr->cdev);

	return result;
	}

	void acpi_processor_thermal_exit(struct acpi_processor *pr,
	struct acpi_device *device)
	{
	if (pr->cdev) {
	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
	sysfs_remove_link(&pr->cdev->device.kobj, "device");
	thermal_cooling_device_unregister(pr->cdev);
	pr->cdev = NULL;
	}
	}