drivers/acpi/processor_thermal.c - kernel/mindspeed - Git at Google

 /*
  * 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
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or (at
  *  your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful, but
  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  *  General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License along
  *  with this program; if not, write to the Free Software Foundation, Inc.,
  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/cpufreq.h>
 #include <linux/sysdev.h>

 #include <asm/uaccess.h>

 #include <acpi/acpi_bus.h>
 #include <acpi/processor.h>
 #include <acpi/acpi_drivers.h>

 #define PREFIX "ACPI: "

 #define ACPI_PROCESSOR_CLASS            "processor"
 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
 ACPI_MODULE_NAME("processor_thermal");

 #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
 #define CPUFREQ_THERMAL_MAX_STEP 3

 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
 static unsigned int acpi_thermal_cpufreq_is_init = 0;

 #define reduction_pctg(cpu) \
 	per_cpu(cpufreq_thermal_reduction_pctg, 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_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu))
 		return 0;
 	return 1;
 }

 static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
 					 unsigned long event, void *data)
 {
 	struct cpufreq_policy *policy = data;
 	unsigned long max_freq = 0;

 	if (event != CPUFREQ_ADJUST)
 		goto out;

 	max_freq = (
 	    policy->cpuinfo.max_freq *
 	    (100 - reduction_pctg(policy->cpu) * 20)
 	) / 100;

 	cpufreq_verify_within_limits(policy, 0, max_freq);

       out:
 	return 0;
 }

 static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
 	.notifier_call = acpi_thermal_cpufreq_notifier,
 };

 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_pctg(cpu);
 }

 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 {
 	int i;

 	if (!cpu_has_cpufreq(cpu))
 		return 0;

 	reduction_pctg(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))
 			cpufreq_update_policy(i);
 	}
 	return 0;
 }

 void acpi_thermal_cpufreq_init(void)
 {
 	int i;

 	i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
 				      CPUFREQ_POLICY_NOTIFIER);
 	if (!i)
 		acpi_thermal_cpufreq_is_init = 1;
 }

 void acpi_thermal_cpufreq_exit(void)
 {
 	if (acpi_thermal_cpufreq_is_init)
 		cpufreq_unregister_notifier
 		    (&acpi_thermal_cpufreq_notifier_block,
 		     CPUFREQ_POLICY_NOTIFIER);

 	acpi_thermal_cpufreq_is_init = 0;
 }

 #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

 int acpi_processor_get_limit_info(struct acpi_processor *pr)
 {

 	if (!pr)
 		return -EINVAL;

 	if (pr->flags.throttling)
 		pr->flags.limit = 1;

 	return 0;
 }

 /* thermal coolign 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_ptg. 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 = acpi_driver_data(device);

 	if (!device || !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 = acpi_driver_data(device);

 	if (!device || !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 = acpi_driver_data(device);
 	int result = 0;
 	int max_pstate;

 	if (!device || !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,
 };
	/*
	* 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
	*
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or (at
	* your option) any later version.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License along
	* with this program; if not, write to the Free Software Foundation, Inc.,
	* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
	*
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/cpufreq.h>
	#include <linux/sysdev.h>

	#include <asm/uaccess.h>

	#include <acpi/acpi_bus.h>
	#include <acpi/processor.h>
	#include <acpi/acpi_drivers.h>

	#define PREFIX "ACPI: "

	#define ACPI_PROCESSOR_CLASS "processor"
	#define _COMPONENT ACPI_PROCESSOR_COMPONENT
	ACPI_MODULE_NAME("processor_thermal");

	#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
	#define CPUFREQ_THERMAL_MAX_STEP 3

	static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
	static unsigned int acpi_thermal_cpufreq_is_init = 0;

	#define reduction_pctg(cpu) \
	per_cpu(cpufreq_thermal_reduction_pctg, 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_thermal_cpufreq_is_init \|\| cpufreq_get_policy(&policy, cpu))
	return 0;
	return 1;
	}

	static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
	unsigned long event, void *data)
	{
	struct cpufreq_policy *policy = data;
	unsigned long max_freq = 0;

	if (event != CPUFREQ_ADJUST)
	goto out;

	max_freq = (
	policy->cpuinfo.max_freq *
	(100 - reduction_pctg(policy->cpu) * 20)
	) / 100;

	cpufreq_verify_within_limits(policy, 0, max_freq);

	out:
	return 0;
	}

	static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
	.notifier_call = acpi_thermal_cpufreq_notifier,
	};

	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_pctg(cpu);
	}

	static int cpufreq_set_cur_state(unsigned int cpu, int state)
	{
	int i;

	if (!cpu_has_cpufreq(cpu))
	return 0;

	reduction_pctg(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))
	cpufreq_update_policy(i);
	}
	return 0;
	}

	void acpi_thermal_cpufreq_init(void)
	{
	int i;

	i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
	CPUFREQ_POLICY_NOTIFIER);
	if (!i)
	acpi_thermal_cpufreq_is_init = 1;
	}

	void acpi_thermal_cpufreq_exit(void)
	{
	if (acpi_thermal_cpufreq_is_init)
	cpufreq_unregister_notifier
	(&acpi_thermal_cpufreq_notifier_block,
	CPUFREQ_POLICY_NOTIFIER);

	acpi_thermal_cpufreq_is_init = 0;
	}

	#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

	int acpi_processor_get_limit_info(struct acpi_processor *pr)
	{

	if (!pr)
	return -EINVAL;

	if (pr->flags.throttling)
	pr->flags.limit = 1;

	return 0;
	}

	/* thermal coolign 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_ptg. 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 = acpi_driver_data(device);

	if (!device \|\| !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 = acpi_driver_data(device);

	if (!device \|\| !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 = acpi_driver_data(device);
	int result = 0;
	int max_pstate;

	if (!device \|\| !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,
	};