[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/config.h>
#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/types.h>
#include <linux/fs.h>
#include <linux/sysfs.h>
#include <linux/mutex.h>

#include <asm/uaccess.h>


/**
 * A few values needed by the userspace governor
 */
static unsigned int	cpu_max_freq[NR_CPUS];
static unsigned int	cpu_min_freq[NR_CPUS];
static unsigned int	cpu_cur_freq[NR_CPUS]; /* current CPU freq */
static unsigned int	cpu_set_freq[NR_CPUS]; /* CPU freq desired by userspace */
static unsigned int	cpu_is_managed[NR_CPUS];

static DEFINE_MUTEX	(userspace_mutex);

#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;

	dprintk("saving cpu_cur_freq of cpu %u to be %u kHz\n", freq->cpu, freq->new);
	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
 * @freq: target frequency in kHz
 * @cpu: CPU for which the frequency is to be set
 *
 * Sets the CPU frequency to freq.
 */
static int cpufreq_set(unsigned int freq, struct cpufreq_policy *policy)
{
	int ret = -EINVAL;

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

	mutex_lock(&userspace_mutex);
	if (!cpu_is_managed[policy->cpu])
		goto err;

	cpu_set_freq[policy->cpu] = freq;

	if (freq < cpu_min_freq[policy->cpu])
		freq = cpu_min_freq[policy->cpu];
	if (freq > cpu_max_freq[policy->cpu])
		freq = 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;
}


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

static ssize_t 
store_speed (struct cpufreq_policy *policy, const char *buf, size_t count) 
{
	unsigned int freq = 0;
	unsigned int ret;

	ret = sscanf (buf, "%u", &freq);
	if (ret != 1)
		return -EINVAL;

	cpufreq_set(freq, policy);

	return count;
}

static struct freq_attr freq_attr_scaling_setspeed = 
{
	.attr = { .name = "scaling_setspeed", .mode = 0644, .owner = THIS_MODULE },
	.show = show_speed,
	.store = store_speed,
};

static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
				   unsigned int event)
{
	unsigned int cpu = policy->cpu;
	switch (event) {
	case CPUFREQ_GOV_START:
		if (!cpu_online(cpu))
			return -EINVAL;
		BUG_ON(!policy->cur);
		mutex_lock(&userspace_mutex);
		cpu_is_managed[cpu] = 1;		
		cpu_min_freq[cpu] = policy->min;
		cpu_max_freq[cpu] = policy->max;
		cpu_cur_freq[cpu] = policy->cur;
		cpu_set_freq[cpu] = policy->cur;
		sysfs_create_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);
		dprintk("managing cpu %u started (%u - %u kHz, currently %u kHz)\n", cpu, cpu_min_freq[cpu], cpu_max_freq[cpu], cpu_cur_freq[cpu]);
		mutex_unlock(&userspace_mutex);
		break;
	case CPUFREQ_GOV_STOP:
		mutex_lock(&userspace_mutex);
		cpu_is_managed[cpu] = 0;
		cpu_min_freq[cpu] = 0;
		cpu_max_freq[cpu] = 0;
		cpu_set_freq[cpu] = 0;
		sysfs_remove_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);
		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,
			cpu_cur_freq[cpu], cpu_set_freq[cpu]);
		if (policy->max < cpu_set_freq[cpu]) {
			__cpufreq_driver_target(policy, policy->max,
						CPUFREQ_RELATION_H);
		}
		else if (policy->min > cpu_set_freq[cpu]) {
			__cpufreq_driver_target(policy, policy->min,
						CPUFREQ_RELATION_L);
		}
		else {
			__cpufreq_driver_target(policy, cpu_set_freq[cpu],
						CPUFREQ_RELATION_L);
		}
		cpu_min_freq[cpu] = policy->min;
		cpu_max_freq[cpu] = policy->max;
		cpu_cur_freq[cpu] = policy->cur;
		mutex_unlock(&userspace_mutex);
		break;
	}
	return 0;
}


struct cpufreq_governor cpufreq_gov_userspace = {
	.name		= "userspace",
	.governor	= cpufreq_governor_userspace,
	.owner		= THIS_MODULE,
};
EXPORT_SYMBOL(cpufreq_gov_userspace);

static int __init cpufreq_gov_userspace_init(void)
{
	cpufreq_register_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
	return cpufreq_register_governor(&cpufreq_gov_userspace);
}


static void __exit cpufreq_gov_userspace_exit(void)
{
	cpufreq_unregister_governor(&cpufreq_gov_userspace);
        cpufreq_unregister_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
}


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

fs_initcall(cpufreq_gov_userspace_init);
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
	14	#include <linux/config.h>
	15	#include <linux/kernel.h>
	16	#include <linux/module.h>
	17	#include <linux/smp.h>
	18	#include <linux/init.h>
	19	#include <linux/spinlock.h>
	20	#include <linux/interrupt.h>
	21	#include <linux/cpufreq.h>
	22	#include <linux/types.h>
	23	#include <linux/fs.h>
	24	#include <linux/sysfs.h>
3fc54d37	25	#include <linux/mutex.h>
1da177e4 LT	26
	27	#include <asm/uaccess.h>
	28
	29
	30	/**
	31	* A few values needed by the userspace governor
	32	*/
	33	static unsigned int cpu_max_freq[NR_CPUS];
	34	static unsigned int cpu_min_freq[NR_CPUS];
	35	static unsigned int cpu_cur_freq[NR_CPUS]; /* current CPU freq */
	36	static unsigned int cpu_set_freq[NR_CPUS]; /* CPU freq desired by userspace */
	37	static unsigned int cpu_is_managed[NR_CPUS];
1da177e4	38
3fc54d37	39	static DEFINE_MUTEX (userspace_mutex);
1da177e4 LT	40
	41	#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_GOVERNOR, "userspace", msg)
	42
	43	/* keep track of frequency transitions */
	44	static int
	45	userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
	46	void *data)
	47	{
	48	struct cpufreq_freqs *freq = data;
	49
	50	dprintk("saving cpu_cur_freq of cpu %u to be %u kHz\n", freq->cpu, freq->new);
	51	cpu_cur_freq[freq->cpu] = freq->new;
	52
	53	return 0;
	54	}
	55
	56	static struct notifier_block userspace_cpufreq_notifier_block = {
	57	.notifier_call = userspace_cpufreq_notifier
	58	};
	59
	60
	61	/**
	62	* cpufreq_set - set the CPU frequency
	63	* @freq: target frequency in kHz
	64	* @cpu: CPU for which the frequency is to be set
	65	*
	66	* Sets the CPU frequency to freq.
	67	*/
c0672860	68	static int cpufreq_set(unsigned int freq, struct cpufreq_policy *policy)
1da177e4 LT	69	{
	70	int ret = -EINVAL;
	71
c0672860	72	dprintk("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
1da177e4	73
3fc54d37	74	mutex_lock(&userspace_mutex);
c0672860	75	if (!cpu_is_managed[policy->cpu])
1da177e4 LT	76	goto err;
1da177e4 LT	77
c0672860	78	cpu_set_freq[policy->cpu] = freq;
1da177e4	79
c0672860 TR	80	if (freq < cpu_min_freq[policy->cpu])
	81	freq = cpu_min_freq[policy->cpu];
	82	if (freq > cpu_max_freq[policy->cpu])
	83	freq = cpu_max_freq[policy->cpu];
1da177e4 LT	84
	85	/*
	86	* We're safe from concurrent calls to ->target() here
3fc54d37	87	* as we hold the userspace_mutex lock. If we were calling
1da177e4	88	* cpufreq_driver_target, a deadlock situation might occur:
3fc54d37	89	* A: cpufreq_set (lock userspace_mutex) -> cpufreq_driver_target(lock policy->lock)
3fc54d37	90	* B: cpufreq_set_policy(lock policy->lock) -> __cpufreq_governor -> cpufreq_governor_userspace (lock userspace_mutex)
1da177e4	91	*/
c0672860	92	ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
1da177e4 LT	93
1da177e4 LT	94	err:
3fc54d37	95	mutex_unlock(&userspace_mutex);
1da177e4 LT	96	return ret;
	97	}
	98
	99
	100	/************************ sysfs interface **********************/
	101	static ssize_t show_speed (struct cpufreq_policy policy, char buf)
	102	{
	103	return sprintf (buf, "%u\n", cpu_cur_freq[policy->cpu]);
	104	}
	105
	106	static ssize_t
	107	store_speed (struct cpufreq_policy policy, const char buf, size_t count)
	108	{
	109	unsigned int freq = 0;
	110	unsigned int ret;
	111
	112	ret = sscanf (buf, "%u", &freq);
	113	if (ret != 1)
	114	return -EINVAL;
	115
c0672860	116	cpufreq_set(freq, policy);
1da177e4 LT	117
	118	return count;
	119	}
	120
	121	static struct freq_attr freq_attr_scaling_setspeed =
	122	{
	123	.attr = { .name = "scaling_setspeed", .mode = 0644, .owner = THIS_MODULE },
	124	.show = show_speed,
	125	.store = store_speed,
	126	};
	127
	128	static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
	129	unsigned int event)
	130	{
	131	unsigned int cpu = policy->cpu;
	132	switch (event) {
	133	case CPUFREQ_GOV_START:
	134	if (!cpu_online(cpu))
	135	return -EINVAL;
	136	BUG_ON(!policy->cur);
3fc54d37	137	mutex_lock(&userspace_mutex);
1da177e4 LT	138	cpu_is_managed[cpu] = 1;
	139	cpu_min_freq[cpu] = policy->min;
	140	cpu_max_freq[cpu] = policy->max;
	141	cpu_cur_freq[cpu] = policy->cur;
	142	cpu_set_freq[cpu] = policy->cur;
	143	sysfs_create_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);
1da177e4	144	dprintk("managing cpu %u started (%u - %u kHz, currently %u kHz)\n", cpu, cpu_min_freq[cpu], cpu_max_freq[cpu], cpu_cur_freq[cpu]);
3fc54d37	145	mutex_unlock(&userspace_mutex);
1da177e4 LT	146	break;
1da177e4 LT	147	case CPUFREQ_GOV_STOP:
3fc54d37	148	mutex_lock(&userspace_mutex);
1da177e4 LT	149	cpu_is_managed[cpu] = 0;
	150	cpu_min_freq[cpu] = 0;
	151	cpu_max_freq[cpu] = 0;
	152	cpu_set_freq[cpu] = 0;
	153	sysfs_remove_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);
	154	dprintk("managing cpu %u stopped\n", cpu);
3fc54d37	155	mutex_unlock(&userspace_mutex);
1da177e4 LT	156	break;
1da177e4 LT	157	case CPUFREQ_GOV_LIMITS:
3fc54d37	158	mutex_lock(&userspace_mutex);
c0672860 TR	159	dprintk("limit event for cpu %u: %u - %u kHz,"
	160	"currently %u kHz, last set to %u kHz\n",
	161	cpu, policy->min, policy->max,
	162	cpu_cur_freq[cpu], cpu_set_freq[cpu]);
1da177e4	163	if (policy->max < cpu_set_freq[cpu]) {
c0672860 TR	164	__cpufreq_driver_target(policy, policy->max,
	165	CPUFREQ_RELATION_H);
	166	}
	167	else if (policy->min > cpu_set_freq[cpu]) {
	168	__cpufreq_driver_target(policy, policy->min,
	169	CPUFREQ_RELATION_L);
1da177e4	170	}
c0672860 TR	171	else {
	172	__cpufreq_driver_target(policy, cpu_set_freq[cpu],
	173	CPUFREQ_RELATION_L);
	174	}
	175	cpu_min_freq[cpu] = policy->min;
	176	cpu_max_freq[cpu] = policy->max;
	177	cpu_cur_freq[cpu] = policy->cur;
3fc54d37	178	mutex_unlock(&userspace_mutex);
1da177e4 LT	179	break;
	180	}
	181	return 0;
	182	}
	183
	184
	185	struct cpufreq_governor cpufreq_gov_userspace = {
	186	.name = "userspace",
	187	.governor = cpufreq_governor_userspace,
	188	.owner = THIS_MODULE,
	189	};
	190	EXPORT_SYMBOL(cpufreq_gov_userspace);
	191
	192	static int __init cpufreq_gov_userspace_init(void)
	193	{
	194	cpufreq_register_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
	195	return cpufreq_register_governor(&cpufreq_gov_userspace);
	196	}
	197
	198
	199	static void __exit cpufreq_gov_userspace_exit(void)
	200	{
	201	cpufreq_unregister_governor(&cpufreq_gov_userspace);
	202	cpufreq_unregister_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
	203	}
	204
	205
	206	MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>, Russell King <rmk@arm.linux.org.uk>");
	207	MODULE_DESCRIPTION ("CPUfreq policy governor 'userspace'");
	208	MODULE_LICENSE ("GPL");
	209
	210	fs_initcall(cpufreq_gov_userspace_init);
	211	module_exit(cpufreq_gov_userspace_exit);