Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 |
/*
* 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;
/* 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;
pr_debug("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;
pr_debug("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;
pr_debug("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;
pr_debug("managing cpu %u stopped\n", cpu);
mutex_unlock(&userspace_mutex);
break;
case CPUFREQ_GOV_LIMITS:
mutex_lock(&userspace_mutex);
pr_debug("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);
|