[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/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>

#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);
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 (!cpu_is_managed[freq->cpu])
		return 0;

	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
 * @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 (!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;
}


static ssize_t show_speed(struct cpufreq_policy *policy, char *buf)
{
	return sprintf(buf, "%u\n", 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++;

		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;
		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);
		cpus_using_userspace_governor--;
		if (cpus_using_userspace_governor == 0) {
			cpufreq_unregister_notifier(
					&userspace_cpufreq_notifier_block,
					CPUFREQ_TRANSITION_NOTIFIER);
		}

		cpu_is_managed[cpu] = 0;
		cpu_min_freq[cpu] = 0;
		cpu_max_freq[cpu] = 0;
		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,
			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 rc;
}


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

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