[mirror_ubuntu-artful-kernel.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 <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 DECLARE_MUTEX	(userspace_sem); 

#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);

	down(&userspace_sem);
	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_sem lock. If we were calling
	 * cpufreq_driver_target, a deadlock situation might occur:
	 * A: cpufreq_set (lock userspace_sem) -> cpufreq_driver_target(lock policy->lock)
	 * B: cpufreq_set_policy(lock policy->lock) -> __cpufreq_governor -> cpufreq_governor_userspace (lock userspace_sem)
	 */
	ret = __cpufreq_driver_target(&current_policy[cpu], freq, 
	      CPUFREQ_RELATION_L);

 err:
	up(&userspace_sem);
	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);
		down(&userspace_sem);
		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]);
		up(&userspace_sem);
		break;
	case CPUFREQ_GOV_STOP:
		down(&userspace_sem);
		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);
		up(&userspace_sem);
		break;
	case CPUFREQ_GOV_LIMITS:
		down(&userspace_sem);
		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));
		up(&userspace_sem);
		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>
	24
	25	#include <asm/uaccess.h>
	26
	27
	28	/**
	29	* A few values needed by the userspace governor
	30	*/
	31	static unsigned int cpu_max_freq[NR_CPUS];
	32	static unsigned int cpu_min_freq[NR_CPUS];
	33	static unsigned int cpu_cur_freq[NR_CPUS]; /* current CPU freq */
	34	static unsigned int cpu_set_freq[NR_CPUS]; /* CPU freq desired by userspace */
	35	static unsigned int cpu_is_managed[NR_CPUS];
	36	static struct cpufreq_policy current_policy[NR_CPUS];
	37
	38	static DECLARE_MUTEX (userspace_sem);
	39
	40	#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_GOVERNOR, "userspace", msg)
	41
	42	/* keep track of frequency transitions */
	43	static int
	44	userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
	45	void *data)
	46	{
	47	struct cpufreq_freqs *freq = data;
	48
	49	dprintk("saving cpu_cur_freq of cpu %u to be %u kHz\n", freq->cpu, freq->new);
	50	cpu_cur_freq[freq->cpu] = freq->new;
	51
	52	return 0;
	53	}
	54
	55	static struct notifier_block userspace_cpufreq_notifier_block = {
	56	.notifier_call = userspace_cpufreq_notifier
	57	};
	58
	59
	60	/**
	61	* cpufreq_set - set the CPU frequency
	62	* @freq: target frequency in kHz
	63	* @cpu: CPU for which the frequency is to be set
	64	*
65	* Sets the CPU frequency to freq.
66	*/
67	static int cpufreq_set(unsigned int freq, unsigned int cpu)
68	{
69	int ret = -EINVAL;
70
71	dprintk("cpufreq_set for cpu %u, freq %u kHz\n", cpu, freq);
72
73	down(&userspace_sem);
74	if (!cpu_is_managed[cpu])
75	goto err;
76
77	cpu_set_freq[cpu] = freq;
78
79	if (freq < cpu_min_freq[cpu])
80	freq = cpu_min_freq[cpu];
81	if (freq > cpu_max_freq[cpu])
82	freq = cpu_max_freq[cpu];
83
84	/*
85	* We're safe from concurrent calls to ->target() here
86	* as we hold the userspace_sem lock. If we were calling
87	* cpufreq_driver_target, a deadlock situation might occur:
88	* A: cpufreq_set (lock userspace_sem) -> cpufreq_driver_target(lock policy->lock)
89	* B: cpufreq_set_policy(lock policy->lock) -> __cpufreq_governor -> cpufreq_governor_userspace (lock userspace_sem)
90	*/
91	ret = __cpufreq_driver_target(&current_policy[cpu], freq,
92	CPUFREQ_RELATION_L);
93
94	err:
95	up(&userspace_sem);
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
116	cpufreq_set(freq, policy->cpu);
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);
137	down(&userspace_sem);
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);
144	memcpy (&current_policy[cpu], policy, sizeof(struct cpufreq_policy));
145	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]);
146	up(&userspace_sem);
147	break;
148	case CPUFREQ_GOV_STOP:
149	down(&userspace_sem);
150	cpu_is_managed[cpu] = 0;
151	cpu_min_freq[cpu] = 0;
152	cpu_max_freq[cpu] = 0;
153	cpu_set_freq[cpu] = 0;
154	sysfs_remove_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);
155	dprintk("managing cpu %u stopped\n", cpu);
156	up(&userspace_sem);
157	break;
158	case CPUFREQ_GOV_LIMITS:
159	down(&userspace_sem);
160	cpu_min_freq[cpu] = policy->min;
161	cpu_max_freq[cpu] = policy->max;
162	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]);
163	if (policy->max < cpu_set_freq[cpu]) {
164	__cpufreq_driver_target(&current_policy[cpu], policy->max,
165	CPUFREQ_RELATION_H);
166	} else if (policy->min > cpu_set_freq[cpu]) {
167	__cpufreq_driver_target(&current_policy[cpu], policy->min,
168	CPUFREQ_RELATION_L);
169	} else {
170	__cpufreq_driver_target(&current_policy[cpu], cpu_set_freq[cpu],
171	CPUFREQ_RELATION_L);
172	}
173	memcpy (&current_policy[cpu], policy, sizeof(struct cpufreq_policy));
174	up(&userspace_sem);
175	break;
176	}
177	return 0;
178	}
179
180
181	struct cpufreq_governor cpufreq_gov_userspace = {
182	.name = "userspace",
183	.governor = cpufreq_governor_userspace,
184	.owner = THIS_MODULE,
185	};
186	EXPORT_SYMBOL(cpufreq_gov_userspace);
187
188	static int __init cpufreq_gov_userspace_init(void)
189	{
190	cpufreq_register_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
191	return cpufreq_register_governor(&cpufreq_gov_userspace);
192	}
193
194
195	static void __exit cpufreq_gov_userspace_exit(void)
196	{
197	cpufreq_unregister_governor(&cpufreq_gov_userspace);
198	cpufreq_unregister_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
199	}
200
201
202	MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>, Russell King <rmk@arm.linux.org.uk>");
203	MODULE_DESCRIPTION ("CPUfreq policy governor 'userspace'");
204	MODULE_LICENSE ("GPL");
205
206	fs_initcall(cpufreq_gov_userspace_init);
207	module_exit(cpufreq_gov_userspace_exit);