[deliverable/linux.git] / drivers / cpufreq / cpufreq_userspace.c


/*
 *  linux/drivers/cpufreq/cpufreq_userspace.c
 *
 *  Copyright (C)  2001 Russell King
 *            (C)  2002 - 2004 Dominik Brodowski <linux@brodo.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/cpufreq.h>
#include <linux/cpu.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/sysfs.h>
#include <linux/mutex.h>

/**
 * A few values needed by the userspace governor
 */
static DEFINE_PER_CPU(unsigned int, cpu_max_freq);
static DEFINE_PER_CPU(unsigned int, cpu_min_freq);
static DEFINE_PER_CPU(unsigned int, cpu_cur_freq); /* current CPU freq */
static DEFINE_PER_CPU(unsigned int, cpu_set_freq); /* CPU freq desired by
							userspace */
static DEFINE_PER_CPU(unsigned int, cpu_is_managed);

static DEFINE_MUTEX(userspace_mutex);
static int cpus_using_userspace_governor;

/* keep track of frequency transitions */
static int
userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
	void *data)
{
	struct cpufreq_freqs *freq = data;

	if (!per_cpu(cpu_is_managed, freq->cpu))
		return 0;

	if (val == CPUFREQ_POSTCHANGE) {
		pr_debug("saving cpu_cur_freq of cpu %u to be %u kHz\n",
				freq->cpu, freq->new);
		per_cpu(cpu_cur_freq, freq->cpu) = freq->new;
	}

	return 0;
}

static struct notifier_block userspace_cpufreq_notifier_block = {
	.notifier_call  = userspace_cpufreq_notifier
};


/**
 * cpufreq_set - set the CPU frequency
 * @policy: pointer to policy struct where freq is being set
 * @freq: target frequency in kHz
 *
 * Sets the CPU frequency to freq.
 */
static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq)
{
	int ret = -EINVAL;

	pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);

	mutex_lock(&userspace_mutex);
	if (!per_cpu(cpu_is_managed, policy->cpu))
		goto err;

	per_cpu(cpu_set_freq, policy->cpu) = freq;

	if (freq < per_cpu(cpu_min_freq, policy->cpu))
		freq = per_cpu(cpu_min_freq, policy->cpu);
	if (freq > per_cpu(cpu_max_freq, policy->cpu))
		freq = per_cpu(cpu_max_freq, policy->cpu);

	/*
	 * We're safe from concurrent calls to ->target() here
	 * as we hold the userspace_mutex lock. If we were calling
	 * cpufreq_driver_target, a deadlock situation might occur:
	 * A: cpufreq_set (lock userspace_mutex) ->
	 *      cpufreq_driver_target(lock policy->lock)
	 * B: cpufreq_set_policy(lock policy->lock) ->
	 *      __cpufreq_governor ->
	 *         cpufreq_governor_userspace (lock userspace_mutex)
	 */
	ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);

 err:
	mutex_unlock(&userspace_mutex);
	return ret;
}


static ssize_t show_speed(struct cpufreq_policy *policy, char *buf)
{
	return sprintf(buf, "%u\n", per_cpu(cpu_cur_freq, policy->cpu));
}

static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
				   unsigned int event)
{
	unsigned int cpu = policy->cpu;
	int rc = 0;

	switch (event) {
	case CPUFREQ_GOV_START:
		if (!cpu_online(cpu))
			return -EINVAL;
		BUG_ON(!policy->cur);
		mutex_lock(&userspace_mutex);

		if (cpus_using_userspace_governor == 0) {
			cpufreq_register_notifier(
					&userspace_cpufreq_notifier_block,
					CPUFREQ_TRANSITION_NOTIFIER);
		}
		cpus_using_userspace_governor++;

		per_cpu(cpu_is_managed, cpu) = 1;
		per_cpu(cpu_min_freq, cpu) = policy->min;
		per_cpu(cpu_max_freq, cpu) = policy->max;
		per_cpu(cpu_cur_freq, cpu) = policy->cur;
		per_cpu(cpu_set_freq, cpu) = policy->cur;
		pr_debug("managing cpu %u started "
			"(%u - %u kHz, currently %u kHz)\n",
				cpu,
				per_cpu(cpu_min_freq, cpu),
				per_cpu(cpu_max_freq, cpu),
				per_cpu(cpu_cur_freq, cpu));

		mutex_unlock(&userspace_mutex);
		break;
	case CPUFREQ_GOV_STOP:
		mutex_lock(&userspace_mutex);
		cpus_using_userspace_governor--;
		if (cpus_using_userspace_governor == 0) {
			cpufreq_unregister_notifier(
					&userspace_cpufreq_notifier_block,
					CPUFREQ_TRANSITION_NOTIFIER);
		}

		per_cpu(cpu_is_managed, cpu) = 0;
		per_cpu(cpu_min_freq, cpu) = 0;
		per_cpu(cpu_max_freq, cpu) = 0;
		per_cpu(cpu_set_freq, cpu) = 0;
		pr_debug("managing cpu %u stopped\n", cpu);
		mutex_unlock(&userspace_mutex);
		break;
	case CPUFREQ_GOV_LIMITS:
		mutex_lock(&userspace_mutex);
		pr_debug("limit event for cpu %u: %u - %u kHz, "
			"currently %u kHz, last set to %u kHz\n",
			cpu, policy->min, policy->max,
			per_cpu(cpu_cur_freq, cpu),
			per_cpu(cpu_set_freq, cpu));
		if (policy->max < per_cpu(cpu_set_freq, cpu)) {
			__cpufreq_driver_target(policy, policy->max,
						CPUFREQ_RELATION_H);
		} else if (policy->min > per_cpu(cpu_set_freq, cpu)) {
			__cpufreq_driver_target(policy, policy->min,
						CPUFREQ_RELATION_L);
		} else {
			__cpufreq_driver_target(policy,
						per_cpu(cpu_set_freq, cpu),
						CPUFREQ_RELATION_L);
		}
		per_cpu(cpu_min_freq, cpu) = policy->min;
		per_cpu(cpu_max_freq, cpu) = policy->max;
		per_cpu(cpu_cur_freq, cpu) = policy->cur;
		mutex_unlock(&userspace_mutex);
		break;
	}
	return rc;
}


#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
static
#endif
struct cpufreq_governor cpufreq_gov_userspace = {
	.name		= "userspace",
	.governor	= cpufreq_governor_userspace,
	.store_setspeed	= cpufreq_set,
	.show_setspeed	= show_speed,
	.owner		= THIS_MODULE,
};

static int __init cpufreq_gov_userspace_init(void)
{
	return cpufreq_register_governor(&cpufreq_gov_userspace);
}


static void __exit cpufreq_gov_userspace_exit(void)
{
	cpufreq_unregister_governor(&cpufreq_gov_userspace);
}


MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, "
		"Russell King <rmk@arm.linux.org.uk>");
MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'");
MODULE_LICENSE("GPL");

#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
fs_initcall(cpufreq_gov_userspace_init);
#else
module_init(cpufreq_gov_userspace_init);
#endif
module_exit(cpufreq_gov_userspace_exit);
Commit	Line	Data
c0672860	1
1da177e4 LT	2	/*
	3	* linux/drivers/cpufreq/cpufreq_userspace.c
	4	*
	5	* Copyright (C) 2001 Russell King
	6	* (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*
	12	*/
	13
db701151 VK	14	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
db701151 VK	15
1da177e4 LT	16	#include <linux/kernel.h>
	17	#include <linux/module.h>
	18	#include <linux/smp.h>
	19	#include <linux/init.h>
	20	#include <linux/spinlock.h>
	21	#include <linux/interrupt.h>
	22	#include <linux/cpufreq.h>
153d7f3f	23	#include <linux/cpu.h>
1da177e4 LT	24	#include <linux/types.h>
	25	#include <linux/fs.h>
	26	#include <linux/sysfs.h>
3fc54d37	27	#include <linux/mutex.h>
1da177e4	28
1da177e4 LT	29	/**
	30	* A few values needed by the userspace governor
	31	*/
b38868aa MT	32	static DEFINE_PER_CPU(unsigned int, cpu_max_freq);
	33	static DEFINE_PER_CPU(unsigned int, cpu_min_freq);
	34	static DEFINE_PER_CPU(unsigned int, cpu_cur_freq); /* current CPU freq */
	35	static DEFINE_PER_CPU(unsigned int, cpu_set_freq); /* CPU freq desired by
	36	userspace */
	37	static DEFINE_PER_CPU(unsigned int, cpu_is_managed);
1da177e4	38
1bceb8d1	39	static DEFINE_MUTEX(userspace_mutex);
c7f652e0	40	static int cpus_using_userspace_governor;
1da177e4	41
1da177e4	42	/* keep track of frequency transitions */
32ee8c3e	43	static int
1da177e4	44	userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
1bceb8d1	45	void *data)
1da177e4	46	{
1bceb8d1	47	struct cpufreq_freqs *freq = data;
1da177e4	48
b38868aa	49	if (!per_cpu(cpu_is_managed, freq->cpu))
c7f652e0 VP	50	return 0;
c7f652e0 VP	51
226dd019 AM	52	if (val == CPUFREQ_POSTCHANGE) {
	53	pr_debug("saving cpu_cur_freq of cpu %u to be %u kHz\n",
	54	freq->cpu, freq->new);
	55	per_cpu(cpu_cur_freq, freq->cpu) = freq->new;
	56	}
1da177e4	57
1bceb8d1	58	return 0;
1da177e4 LT	59	}
	60
	61	static struct notifier_block userspace_cpufreq_notifier_block = {
1bceb8d1	62	.notifier_call = userspace_cpufreq_notifier
1da177e4 LT	63	};
	64
	65
32ee8c3e	66	/**
1da177e4	67	* cpufreq_set - set the CPU frequency
9e76988e	68	* @policy: pointer to policy struct where freq is being set
1da177e4	69	* @freq: target frequency in kHz
1da177e4 LT	70	*
	71	* Sets the CPU frequency to freq.
	72	*/
9e76988e	73	static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq)
1da177e4 LT	74	{
	75	int ret = -EINVAL;
	76
2d06d8c4	77	pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
1da177e4	78
3fc54d37	79	mutex_lock(&userspace_mutex);
b38868aa	80	if (!per_cpu(cpu_is_managed, policy->cpu))
1da177e4 LT	81	goto err;
1da177e4 LT	82
b38868aa	83	per_cpu(cpu_set_freq, policy->cpu) = freq;
1da177e4	84
b38868aa MT	85	if (freq < per_cpu(cpu_min_freq, policy->cpu))
	86	freq = per_cpu(cpu_min_freq, policy->cpu);
	87	if (freq > per_cpu(cpu_max_freq, policy->cpu))
	88	freq = per_cpu(cpu_max_freq, policy->cpu);
1da177e4 LT	89
	90	/*
	91	* We're safe from concurrent calls to ->target() here
3fc54d37	92	* as we hold the userspace_mutex lock. If we were calling
1da177e4	93	* cpufreq_driver_target, a deadlock situation might occur:
1bceb8d1 DJ	94	* A: cpufreq_set (lock userspace_mutex) ->
	95	* cpufreq_driver_target(lock policy->lock)
	96	* B: cpufreq_set_policy(lock policy->lock) ->
	97	* __cpufreq_governor ->
	98	* cpufreq_governor_userspace (lock userspace_mutex)
1da177e4	99	*/
c0672860	100	ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
1da177e4 LT	101
1da177e4 LT	102	err:
3fc54d37	103	mutex_unlock(&userspace_mutex);
1da177e4 LT	104	return ret;
	105	}
	106
	107
9e76988e	108	static ssize_t show_speed(struct cpufreq_policy policy, char buf)
1da177e4	109	{
b38868aa	110	return sprintf(buf, "%u\n", per_cpu(cpu_cur_freq, policy->cpu));
1da177e4 LT	111	}
1da177e4 LT	112
1da177e4 LT	113	static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
	114	unsigned int event)
	115	{
	116	unsigned int cpu = policy->cpu;
914f7c31 JG	117	int rc = 0;
914f7c31 JG	118
1da177e4 LT	119	switch (event) {
	120	case CPUFREQ_GOV_START:
	121	if (!cpu_online(cpu))
	122	return -EINVAL;
	123	BUG_ON(!policy->cur);
3fc54d37	124	mutex_lock(&userspace_mutex);
914f7c31	125
c7f652e0 VP	126	if (cpus_using_userspace_governor == 0) {
	127	cpufreq_register_notifier(
	128	&userspace_cpufreq_notifier_block,
	129	CPUFREQ_TRANSITION_NOTIFIER);
	130	}
	131	cpus_using_userspace_governor++;
	132
b38868aa MT	133	per_cpu(cpu_is_managed, cpu) = 1;
	134	per_cpu(cpu_min_freq, cpu) = policy->min;
	135	per_cpu(cpu_max_freq, cpu) = policy->max;
	136	per_cpu(cpu_cur_freq, cpu) = policy->cur;
	137	per_cpu(cpu_set_freq, cpu) = policy->cur;
2d06d8c4	138	pr_debug("managing cpu %u started "
b38868aa MT	139	"(%u - %u kHz, currently %u kHz)\n",
	140	cpu,
	141	per_cpu(cpu_min_freq, cpu),
	142	per_cpu(cpu_max_freq, cpu),
	143	per_cpu(cpu_cur_freq, cpu));
9e76988e	144
3fc54d37	145	mutex_unlock(&userspace_mutex);
1da177e4 LT	146	break;
1da177e4 LT	147	case CPUFREQ_GOV_STOP:
3fc54d37	148	mutex_lock(&userspace_mutex);
c7f652e0 VP	149	cpus_using_userspace_governor--;
	150	if (cpus_using_userspace_governor == 0) {
	151	cpufreq_unregister_notifier(
	152	&userspace_cpufreq_notifier_block,
	153	CPUFREQ_TRANSITION_NOTIFIER);
	154	}
	155
b38868aa MT	156	per_cpu(cpu_is_managed, cpu) = 0;
	157	per_cpu(cpu_min_freq, cpu) = 0;
	158	per_cpu(cpu_max_freq, cpu) = 0;
	159	per_cpu(cpu_set_freq, cpu) = 0;
2d06d8c4	160	pr_debug("managing cpu %u stopped\n", cpu);
3fc54d37	161	mutex_unlock(&userspace_mutex);
1da177e4 LT	162	break;
1da177e4 LT	163	case CPUFREQ_GOV_LIMITS:
3fc54d37	164	mutex_lock(&userspace_mutex);
2d06d8c4	165	pr_debug("limit event for cpu %u: %u - %u kHz, "
c0672860 TR	166	"currently %u kHz, last set to %u kHz\n",
c0672860 TR	167	cpu, policy->min, policy->max,
b38868aa MT	168	per_cpu(cpu_cur_freq, cpu),
	169	per_cpu(cpu_set_freq, cpu));
	170	if (policy->max < per_cpu(cpu_set_freq, cpu)) {
c0672860 TR	171	__cpufreq_driver_target(policy, policy->max,
c0672860 TR	172	CPUFREQ_RELATION_H);
b38868aa	173	} else if (policy->min > per_cpu(cpu_set_freq, cpu)) {
c0672860 TR	174	__cpufreq_driver_target(policy, policy->min,
c0672860 TR	175	CPUFREQ_RELATION_L);
b38868aa MT	176	} else {
	177	__cpufreq_driver_target(policy,
	178	per_cpu(cpu_set_freq, cpu),
c0672860 TR	179	CPUFREQ_RELATION_L);
c0672860 TR	180	}
b38868aa MT	181	per_cpu(cpu_min_freq, cpu) = policy->min;
	182	per_cpu(cpu_max_freq, cpu) = policy->max;
	183	per_cpu(cpu_cur_freq, cpu) = policy->cur;
3fc54d37	184	mutex_unlock(&userspace_mutex);
1da177e4 LT	185	break;
1da177e4 LT	186	}
914f7c31	187	return rc;
1da177e4 LT	188	}
	189
	190
c4d14bc0 SW	191	#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
	192	static
	193	#endif
1da177e4 LT	194	struct cpufreq_governor cpufreq_gov_userspace = {
	195	.name = "userspace",
	196	.governor = cpufreq_governor_userspace,
9e76988e VP	197	.store_setspeed = cpufreq_set,
9e76988e VP	198	.show_setspeed = show_speed,
1da177e4 LT	199	.owner = THIS_MODULE,
1da177e4 LT	200	};
1da177e4 LT	201
	202	static int __init cpufreq_gov_userspace_init(void)
	203	{
1da177e4 LT	204	return cpufreq_register_governor(&cpufreq_gov_userspace);
	205	}
	206
	207
	208	static void __exit cpufreq_gov_userspace_exit(void)
	209	{
	210	cpufreq_unregister_governor(&cpufreq_gov_userspace);
1da177e4 LT	211	}
	212
	213
1bceb8d1 DJ	214	MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, "
	215	"Russell King <rmk@arm.linux.org.uk>");
	216	MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'");
	217	MODULE_LICENSE("GPL");
1da177e4	218
6915719b	219	#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
1da177e4	220	fs_initcall(cpufreq_gov_userspace_init);
6915719b JW	221	#else
	222	module_init(cpufreq_gov_userspace_init);
	223	#endif
1da177e4	224	module_exit(cpufreq_gov_userspace_exit);