[GitHub/mt8127/android_kernel_alcatel_ttab.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 struct cpufreq_policy current_policy[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, unsigned int cpu)
{
	int ret = -EINVAL;

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

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

	cpu_set_freq[cpu] = freq;

	if (freq < cpu_min_freq[cpu])
		freq = cpu_min_freq[cpu];
	if (freq > cpu_max_freq[cpu])
		freq = cpu_max_freq[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(&current_policy[cpu], 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->cpu);

	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);
		memcpy (&current_policy[cpu], policy, sizeof(struct cpufreq_policy));
		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);
		cpu_min_freq[cpu] = policy->min;
		cpu_max_freq[cpu] = policy->max;
		dprintk("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n", cpu, cpu_min_freq[cpu], cpu_max_freq[cpu], cpu_cur_freq[cpu], cpu_set_freq[cpu]);
		if (policy->max < cpu_set_freq[cpu]) {
			__cpufreq_driver_target(&current_policy[cpu], policy->max, 
			      CPUFREQ_RELATION_H);
		} else if (policy->min > cpu_set_freq[cpu]) {
			__cpufreq_driver_target(&current_policy[cpu], policy->min, 
			      CPUFREQ_RELATION_L);
		} else {
			__cpufreq_driver_target(&current_policy[cpu], cpu_set_freq[cpu],
			      CPUFREQ_RELATION_L);
		}
		memcpy (&current_policy[cpu], policy, sizeof(struct cpufreq_policy));
		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
1da177e4 LT	1	/*
	2	* linux/drivers/cpufreq/cpufreq_userspace.c
	3	*
	4	* Copyright (C) 2001 Russell King
	5	* (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*
	11	*/
	12
	13	#include <linux/config.h>
	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>
	21	#include <linux/types.h>
	22	#include <linux/fs.h>
	23	#include <linux/sysfs.h>
3fc54d37	24	#include <linux/mutex.h>
1da177e4 LT	25
	26	#include <asm/uaccess.h>
	27
	28
	29	/**
	30	* A few values needed by the userspace governor
	31	*/
	32	static unsigned int cpu_max_freq[NR_CPUS];
	33	static unsigned int cpu_min_freq[NR_CPUS];
	34	static unsigned int cpu_cur_freq[NR_CPUS]; /* current CPU freq */
	35	static unsigned int cpu_set_freq[NR_CPUS]; /* CPU freq desired by userspace */
	36	static unsigned int cpu_is_managed[NR_CPUS];
	37	static struct cpufreq_policy current_policy[NR_CPUS];
	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	*/
	68	static int cpufreq_set(unsigned int freq, unsigned int cpu)
	69	{
	70	int ret = -EINVAL;
	71
	72	dprintk("cpufreq_set for cpu %u, freq %u kHz\n", cpu, freq);
	73
3fc54d37	74	mutex_lock(&userspace_mutex);
1da177e4 LT	75	if (!cpu_is_managed[cpu])
	76	goto err;
	77
	78	cpu_set_freq[cpu] = freq;
	79
	80	if (freq < cpu_min_freq[cpu])
	81	freq = cpu_min_freq[cpu];
	82	if (freq > cpu_max_freq[cpu])
	83	freq = cpu_max_freq[cpu];
	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 AM	89	* A: cpufreq_set (lock userspace_mutex) -> cpufreq_driver_target(lock policy->lock)
3fc54d37 AM	90	* B: cpufreq_set_policy(lock policy->lock) -> __cpufreq_governor -> cpufreq_governor_userspace (lock userspace_mutex)
1da177e4 LT	91	*/
	92	ret = __cpufreq_driver_target(&current_policy[cpu], freq,
	93	CPUFREQ_RELATION_L);
	94
	95	err:
3fc54d37	96	mutex_unlock(&userspace_mutex);
1da177e4 LT	97	return ret;
	98	}
	99
	100
	101	/************************ sysfs interface **********************/
	102	static ssize_t show_speed (struct cpufreq_policy policy, char buf)
	103	{
	104	return sprintf (buf, "%u\n", cpu_cur_freq[policy->cpu]);
	105	}
	106
	107	static ssize_t
	108	store_speed (struct cpufreq_policy policy, const char buf, size_t count)
	109	{
	110	unsigned int freq = 0;
	111	unsigned int ret;
	112
	113	ret = sscanf (buf, "%u", &freq);
	114	if (ret != 1)
	115	return -EINVAL;
	116
	117	cpufreq_set(freq, policy->cpu);
	118
	119	return count;
	120	}
	121
	122	static struct freq_attr freq_attr_scaling_setspeed =
	123	{
	124	.attr = { .name = "scaling_setspeed", .mode = 0644, .owner = THIS_MODULE },
	125	.show = show_speed,
	126	.store = store_speed,
	127	};
	128
	129	static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
	130	unsigned int event)
	131	{
	132	unsigned int cpu = policy->cpu;
	133	switch (event) {
	134	case CPUFREQ_GOV_START:
	135	if (!cpu_online(cpu))
	136	return -EINVAL;
	137	BUG_ON(!policy->cur);
3fc54d37	138	mutex_lock(&userspace_mutex);
1da177e4 LT	139	cpu_is_managed[cpu] = 1;
	140	cpu_min_freq[cpu] = policy->min;
	141	cpu_max_freq[cpu] = policy->max;
	142	cpu_cur_freq[cpu] = policy->cur;
	143	cpu_set_freq[cpu] = policy->cur;
	144	sysfs_create_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);
	145	memcpy (&current_policy[cpu], policy, sizeof(struct cpufreq_policy));
	146	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	147	mutex_unlock(&userspace_mutex);
1da177e4 LT	148	break;
1da177e4 LT	149	case CPUFREQ_GOV_STOP:
3fc54d37	150	mutex_lock(&userspace_mutex);
1da177e4 LT	151	cpu_is_managed[cpu] = 0;
	152	cpu_min_freq[cpu] = 0;
	153	cpu_max_freq[cpu] = 0;
	154	cpu_set_freq[cpu] = 0;
	155	sysfs_remove_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);
	156	dprintk("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);
1da177e4 LT	161	cpu_min_freq[cpu] = policy->min;
	162	cpu_max_freq[cpu] = policy->max;
	163	dprintk("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n", cpu, cpu_min_freq[cpu], cpu_max_freq[cpu], cpu_cur_freq[cpu], cpu_set_freq[cpu]);
	164	if (policy->max < cpu_set_freq[cpu]) {
	165	__cpufreq_driver_target(&current_policy[cpu], policy->max,
	166	CPUFREQ_RELATION_H);
	167	} else if (policy->min > cpu_set_freq[cpu]) {
	168	__cpufreq_driver_target(&current_policy[cpu], policy->min,
	169	CPUFREQ_RELATION_L);
	170	} else {
	171	__cpufreq_driver_target(&current_policy[cpu], cpu_set_freq[cpu],
	172	CPUFREQ_RELATION_L);
	173	}
	174	memcpy (&current_policy[cpu], policy, sizeof(struct cpufreq_policy));
3fc54d37	175	mutex_unlock(&userspace_mutex);
1da177e4 LT	176	break;
	177	}
	178	return 0;
	179	}
	180
	181
	182	struct cpufreq_governor cpufreq_gov_userspace = {
	183	.name = "userspace",
	184	.governor = cpufreq_governor_userspace,
	185	.owner = THIS_MODULE,
	186	};
	187	EXPORT_SYMBOL(cpufreq_gov_userspace);
	188
	189	static int __init cpufreq_gov_userspace_init(void)
	190	{
	191	cpufreq_register_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
	192	return cpufreq_register_governor(&cpufreq_gov_userspace);
	193	}
	194
	195
	196	static void __exit cpufreq_gov_userspace_exit(void)
	197	{
	198	cpufreq_unregister_governor(&cpufreq_gov_userspace);
	199	cpufreq_unregister_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
	200	}
	201
	202
	203	MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>, Russell King <rmk@arm.linux.org.uk>");
	204	MODULE_DESCRIPTION ("CPUfreq policy governor 'userspace'");
	205	MODULE_LICENSE ("GPL");
	206
	207	fs_initcall(cpufreq_gov_userspace_init);
	208	module_exit(cpufreq_gov_userspace_exit);