[deliverable/linux.git] / drivers / acpi / processor_thermal.c

/*
 * 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.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#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 <asm/uaccess.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

/* 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_pctg. 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,
};
Commit	Line	Data
	1	/*
	2	* processor_thermal.c - Passive cooling submodule of the ACPI processor driver
	3	*
	4	* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
	5	* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
	6	* Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>
	7	* Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
	8	* - Added processor hotplug support
	9	*
	10	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	11	*
	12	* This program is free software; you can redistribute it and/or modify
	13	* it under the terms of the GNU General Public License as published by
	14	* the Free Software Foundation; either version 2 of the License, or (at
	15	* your option) any later version.
	16	*
	17	* This program is distributed in the hope that it will be useful, but
	18	* WITHOUT ANY WARRANTY; without even the implied warranty of
	19	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	20	* General Public License for more details.
	21	*
	22	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	23	*/
	24
	25	#include <linux/kernel.h>
	26	#include <linux/module.h>
	27	#include <linux/init.h>
	28	#include <linux/cpufreq.h>
	29	#include <linux/acpi.h>
	30	#include <acpi/processor.h>
	31	#include <asm/uaccess.h>
	32
	33	#define PREFIX "ACPI: "
	34
	35	#define ACPI_PROCESSOR_CLASS "processor"
	36	#define _COMPONENT ACPI_PROCESSOR_COMPONENT
	37	ACPI_MODULE_NAME("processor_thermal");
	38
	39	#ifdef CONFIG_CPU_FREQ
	40
	41	/* If a passive cooling situation is detected, primarily CPUfreq is used, as it
	42	* offers (in most cases) voltage scaling in addition to frequency scaling, and
	43	* thus a cubic (instead of linear) reduction of energy. Also, we allow for
	44	* _any_ cpufreq driver and not only the acpi-cpufreq driver.
	45	*/
	46
	47	#define CPUFREQ_THERMAL_MIN_STEP 0
	48	#define CPUFREQ_THERMAL_MAX_STEP 3
	49
	50	static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
	51	static unsigned int acpi_thermal_cpufreq_is_init = 0;
	52
	53	#define reduction_pctg(cpu) \
	54	per_cpu(cpufreq_thermal_reduction_pctg, phys_package_first_cpu(cpu))
	55
	56	/*
	57	* Emulate "per package data" using per cpu data (which should really be
	58	* provided elsewhere)
	59	*
	60	* Note we can lose a CPU on cpu hotunplug, in this case we forget the state
	61	* temporarily. Fortunately that's not a big issue here (I hope)
	62	*/
	63	static int phys_package_first_cpu(int cpu)
	64	{
	65	int i;
	66	int id = topology_physical_package_id(cpu);
	67
	68	for_each_online_cpu(i)
	69	if (topology_physical_package_id(i) == id)
	70	return i;
	71	return 0;
	72	}
	73
	74	static int cpu_has_cpufreq(unsigned int cpu)
	75	{
	76	struct cpufreq_policy policy;
	77	if (!acpi_thermal_cpufreq_is_init \|\| cpufreq_get_policy(&policy, cpu))
	78	return 0;
	79	return 1;
	80	}
	81
	82	static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
	83	unsigned long event, void *data)
	84	{
	85	struct cpufreq_policy *policy = data;
	86	unsigned long max_freq = 0;
	87
	88	if (event != CPUFREQ_ADJUST)
	89	goto out;
	90
	91	max_freq = (
	92	policy->cpuinfo.max_freq *
	93	(100 - reduction_pctg(policy->cpu) * 20)
	94	) / 100;
	95
	96	cpufreq_verify_within_limits(policy, 0, max_freq);
	97
	98	out:
	99	return 0;
	100	}
	101
	102	static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
	103	.notifier_call = acpi_thermal_cpufreq_notifier,
	104	};
	105
	106	static int cpufreq_get_max_state(unsigned int cpu)
	107	{
	108	if (!cpu_has_cpufreq(cpu))
	109	return 0;
	110
	111	return CPUFREQ_THERMAL_MAX_STEP;
	112	}
	113
	114	static int cpufreq_get_cur_state(unsigned int cpu)
	115	{
	116	if (!cpu_has_cpufreq(cpu))
	117	return 0;
	118
	119	return reduction_pctg(cpu);
	120	}
	121
	122	static int cpufreq_set_cur_state(unsigned int cpu, int state)
	123	{
	124	int i;
	125
	126	if (!cpu_has_cpufreq(cpu))
	127	return 0;
	128
	129	reduction_pctg(cpu) = state;
	130
	131	/*
	132	* Update all the CPUs in the same package because they all
	133	* contribute to the temperature and often share the same
	134	* frequency.
	135	*/
	136	for_each_online_cpu(i) {
	137	if (topology_physical_package_id(i) ==
	138	topology_physical_package_id(cpu))
	139	cpufreq_update_policy(i);
	140	}
	141	return 0;
	142	}
	143
	144	void acpi_thermal_cpufreq_init(void)
	145	{
	146	int i;
	147
	148	i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
	149	CPUFREQ_POLICY_NOTIFIER);
	150	if (!i)
	151	acpi_thermal_cpufreq_is_init = 1;
	152	}
	153
	154	void acpi_thermal_cpufreq_exit(void)
	155	{
	156	if (acpi_thermal_cpufreq_is_init)
	157	cpufreq_unregister_notifier
	158	(&acpi_thermal_cpufreq_notifier_block,
	159	CPUFREQ_POLICY_NOTIFIER);
	160
	161	acpi_thermal_cpufreq_is_init = 0;
	162	}
	163
	164	#else /* ! CONFIG_CPU_FREQ */
	165	static int cpufreq_get_max_state(unsigned int cpu)
	166	{
	167	return 0;
	168	}
	169
	170	static int cpufreq_get_cur_state(unsigned int cpu)
	171	{
	172	return 0;
	173	}
	174
	175	static int cpufreq_set_cur_state(unsigned int cpu, int state)
	176	{
	177	return 0;
	178	}
	179
	180	#endif
	181
	182	/* thermal cooling device callbacks */
	183	static int acpi_processor_max_state(struct acpi_processor *pr)
	184	{
	185	int max_state = 0;
	186
	187	/*
	188	* There exists four states according to
	189	* cpufreq_thermal_reduction_pctg. 0, 1, 2, 3
	190	*/
	191	max_state += cpufreq_get_max_state(pr->id);
	192	if (pr->flags.throttling)
	193	max_state += (pr->throttling.state_count -1);
	194
	195	return max_state;
	196	}
	197	static int
	198	processor_get_max_state(struct thermal_cooling_device *cdev,
	199	unsigned long *state)
	200	{
	201	struct acpi_device *device = cdev->devdata;
	202	struct acpi_processor *pr;
	203
	204	if (!device)
	205	return -EINVAL;
	206
	207	pr = acpi_driver_data(device);
	208	if (!pr)
	209	return -EINVAL;
	210
	211	*state = acpi_processor_max_state(pr);
	212	return 0;
	213	}
	214
	215	static int
	216	processor_get_cur_state(struct thermal_cooling_device *cdev,
	217	unsigned long *cur_state)
	218	{
	219	struct acpi_device *device = cdev->devdata;
	220	struct acpi_processor *pr;
	221
	222	if (!device)
	223	return -EINVAL;
	224
	225	pr = acpi_driver_data(device);
	226	if (!pr)
	227	return -EINVAL;
	228
	229	*cur_state = cpufreq_get_cur_state(pr->id);
	230	if (pr->flags.throttling)
	231	*cur_state += pr->throttling.state;
	232	return 0;
	233	}
	234
	235	static int
	236	processor_set_cur_state(struct thermal_cooling_device *cdev,
	237	unsigned long state)
	238	{
	239	struct acpi_device *device = cdev->devdata;
	240	struct acpi_processor *pr;
	241	int result = 0;
	242	int max_pstate;
	243
	244	if (!device)
	245	return -EINVAL;
	246
	247	pr = acpi_driver_data(device);
	248	if (!pr)
	249	return -EINVAL;
	250
	251	max_pstate = cpufreq_get_max_state(pr->id);
	252
	253	if (state > acpi_processor_max_state(pr))
	254	return -EINVAL;
	255
	256	if (state <= max_pstate) {
	257	if (pr->flags.throttling && pr->throttling.state)
	258	result = acpi_processor_set_throttling(pr, 0, false);
	259	cpufreq_set_cur_state(pr->id, state);
	260	} else {
	261	cpufreq_set_cur_state(pr->id, max_pstate);
	262	result = acpi_processor_set_throttling(pr,
	263	state - max_pstate, false);
	264	}
	265	return result;
	266	}
	267
	268	const struct thermal_cooling_device_ops processor_cooling_ops = {
	269	.get_max_state = processor_get_max_state,
	270	.get_cur_state = processor_get_cur_state,
	271	.set_cur_state = processor_set_cur_state,
	272	};