[net-next-2.6.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;

#define dprintk(msg...) \
	cpufreq_debug_printk(CPUFREQ_DEBUG_GOVERNOR, "userspace", msg)

/* 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;

	dprintk("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;

	dprintk("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;
		dprintk("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;
		dprintk("managing cpu %u stopped\n", cpu);
		mutex_unlock(&userspace_mutex);
		break;
	case CPUFREQ_GOV_LIMITS:
		mutex_lock(&userspace_mutex);
		dprintk("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
b38868aa MT	40	#define dprintk(msg...) \
b38868aa MT	41	cpufreq_debug_printk(CPUFREQ_DEBUG_GOVERNOR, "userspace", msg)
1da177e4 LT	42
1da177e4 LT	43	/* keep track of frequency transitions */
32ee8c3e	44	static int
1da177e4	45	userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
1bceb8d1	46	void *data)
1da177e4	47	{
1bceb8d1	48	struct cpufreq_freqs *freq = data;
1da177e4	49
b38868aa	50	if (!per_cpu(cpu_is_managed, freq->cpu))
c7f652e0 VP	51	return 0;
	52
	53	dprintk("saving cpu_cur_freq of cpu %u to be %u kHz\n",
	54	freq->cpu, freq->new);
b38868aa	55	per_cpu(cpu_cur_freq, freq->cpu) = freq->new;
1da177e4	56
1bceb8d1	57	return 0;
1da177e4 LT	58	}
	59
	60	static struct notifier_block userspace_cpufreq_notifier_block = {
1bceb8d1	61	.notifier_call = userspace_cpufreq_notifier
1da177e4 LT	62	};
	63
	64
32ee8c3e	65	/**
1da177e4	66	* cpufreq_set - set the CPU frequency
9e76988e	67	* @policy: pointer to policy struct where freq is being set
1da177e4	68	* @freq: target frequency in kHz
1da177e4 LT	69	*
	70	* Sets the CPU frequency to freq.
	71	*/
9e76988e	72	static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq)
1da177e4 LT	73	{
	74	int ret = -EINVAL;
	75
c0672860	76	dprintk("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
1da177e4	77
3fc54d37	78	mutex_lock(&userspace_mutex);
b38868aa	79	if (!per_cpu(cpu_is_managed, policy->cpu))
1da177e4 LT	80	goto err;
1da177e4 LT	81
b38868aa	82	per_cpu(cpu_set_freq, policy->cpu) = freq;
1da177e4	83
b38868aa MT	84	if (freq < per_cpu(cpu_min_freq, policy->cpu))
	85	freq = per_cpu(cpu_min_freq, policy->cpu);
	86	if (freq > per_cpu(cpu_max_freq, policy->cpu))
	87	freq = per_cpu(cpu_max_freq, policy->cpu);
1da177e4 LT	88
	89	/*
	90	* We're safe from concurrent calls to ->target() here
3fc54d37	91	* as we hold the userspace_mutex lock. If we were calling
1da177e4	92	* cpufreq_driver_target, a deadlock situation might occur:
1bceb8d1 DJ	93	* A: cpufreq_set (lock userspace_mutex) ->
	94	* cpufreq_driver_target(lock policy->lock)
	95	* B: cpufreq_set_policy(lock policy->lock) ->
	96	* __cpufreq_governor ->
	97	* cpufreq_governor_userspace (lock userspace_mutex)
1da177e4	98	*/
c0672860	99	ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
1da177e4 LT	100
1da177e4 LT	101	err:
3fc54d37	102	mutex_unlock(&userspace_mutex);
1da177e4 LT	103	return ret;
	104	}
	105
	106
9e76988e	107	static ssize_t show_speed(struct cpufreq_policy policy, char buf)
1da177e4	108	{
b38868aa	109	return sprintf(buf, "%u\n", per_cpu(cpu_cur_freq, policy->cpu));
1da177e4 LT	110	}
1da177e4 LT	111
1da177e4 LT	112	static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
	113	unsigned int event)
	114	{
	115	unsigned int cpu = policy->cpu;
914f7c31 JG	116	int rc = 0;
914f7c31 JG	117
1da177e4 LT	118	switch (event) {
	119	case CPUFREQ_GOV_START:
	120	if (!cpu_online(cpu))
	121	return -EINVAL;
	122	BUG_ON(!policy->cur);
3fc54d37	123	mutex_lock(&userspace_mutex);
914f7c31	124
c7f652e0 VP	125	if (cpus_using_userspace_governor == 0) {
	126	cpufreq_register_notifier(
	127	&userspace_cpufreq_notifier_block,
	128	CPUFREQ_TRANSITION_NOTIFIER);
	129	}
	130	cpus_using_userspace_governor++;
	131
b38868aa MT	132	per_cpu(cpu_is_managed, cpu) = 1;
	133	per_cpu(cpu_min_freq, cpu) = policy->min;
	134	per_cpu(cpu_max_freq, cpu) = policy->max;
	135	per_cpu(cpu_cur_freq, cpu) = policy->cur;
	136	per_cpu(cpu_set_freq, cpu) = policy->cur;
	137	dprintk("managing cpu %u started "
	138	"(%u - %u kHz, currently %u kHz)\n",
	139	cpu,
	140	per_cpu(cpu_min_freq, cpu),
	141	per_cpu(cpu_max_freq, cpu),
	142	per_cpu(cpu_cur_freq, cpu));
9e76988e	143
3fc54d37	144	mutex_unlock(&userspace_mutex);
1da177e4 LT	145	break;
1da177e4 LT	146	case CPUFREQ_GOV_STOP:
3fc54d37	147	mutex_lock(&userspace_mutex);
c7f652e0 VP	148	cpus_using_userspace_governor--;
	149	if (cpus_using_userspace_governor == 0) {
	150	cpufreq_unregister_notifier(
	151	&userspace_cpufreq_notifier_block,
	152	CPUFREQ_TRANSITION_NOTIFIER);
	153	}
	154
b38868aa MT	155	per_cpu(cpu_is_managed, cpu) = 0;
	156	per_cpu(cpu_min_freq, cpu) = 0;
	157	per_cpu(cpu_max_freq, cpu) = 0;
	158	per_cpu(cpu_set_freq, cpu) = 0;
1da177e4	159	dprintk("managing cpu %u stopped\n", cpu);
3fc54d37	160	mutex_unlock(&userspace_mutex);
1da177e4 LT	161	break;
1da177e4 LT	162	case CPUFREQ_GOV_LIMITS:
3fc54d37	163	mutex_lock(&userspace_mutex);
b38868aa	164	dprintk("limit event for cpu %u: %u - %u kHz, "
c0672860 TR	165	"currently %u kHz, last set to %u kHz\n",
c0672860 TR	166	cpu, policy->min, policy->max,
b38868aa MT	167	per_cpu(cpu_cur_freq, cpu),
	168	per_cpu(cpu_set_freq, cpu));
	169	if (policy->max < per_cpu(cpu_set_freq, cpu)) {
c0672860 TR	170	__cpufreq_driver_target(policy, policy->max,
c0672860 TR	171	CPUFREQ_RELATION_H);
b38868aa	172	} else if (policy->min > per_cpu(cpu_set_freq, cpu)) {
c0672860 TR	173	__cpufreq_driver_target(policy, policy->min,
c0672860 TR	174	CPUFREQ_RELATION_L);
b38868aa MT	175	} else {
	176	__cpufreq_driver_target(policy,
	177	per_cpu(cpu_set_freq, cpu),
c0672860 TR	178	CPUFREQ_RELATION_L);
c0672860 TR	179	}
b38868aa MT	180	per_cpu(cpu_min_freq, cpu) = policy->min;
	181	per_cpu(cpu_max_freq, cpu) = policy->max;
	182	per_cpu(cpu_cur_freq, cpu) = policy->cur;
3fc54d37	183	mutex_unlock(&userspace_mutex);
1da177e4 LT	184	break;
1da177e4 LT	185	}
914f7c31	186	return rc;
1da177e4 LT	187	}
	188
	189
c4d14bc0 SW	190	#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
	191	static
	192	#endif
1da177e4 LT	193	struct cpufreq_governor cpufreq_gov_userspace = {
	194	.name = "userspace",
	195	.governor = cpufreq_governor_userspace,
9e76988e VP	196	.store_setspeed = cpufreq_set,
9e76988e VP	197	.show_setspeed = show_speed,
1da177e4 LT	198	.owner = THIS_MODULE,
1da177e4 LT	199	};
1da177e4 LT	200
	201	static int __init cpufreq_gov_userspace_init(void)
	202	{
1da177e4 LT	203	return cpufreq_register_governor(&cpufreq_gov_userspace);
	204	}
	205
	206
	207	static void __exit cpufreq_gov_userspace_exit(void)
	208	{
	209	cpufreq_unregister_governor(&cpufreq_gov_userspace);
1da177e4 LT	210	}
	211
	212
1bceb8d1 DJ	213	MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, "
	214	"Russell King <rmk@arm.linux.org.uk>");
	215	MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'");
	216	MODULE_LICENSE("GPL");
1da177e4	217
6915719b	218	#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
1da177e4	219	fs_initcall(cpufreq_gov_userspace_init);
6915719b JW	220	#else
	221	module_init(cpufreq_gov_userspace_init);
	222	#endif
1da177e4	223	module_exit(cpufreq_gov_userspace_exit);