[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.
 *
 */

#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;

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