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// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/drivers/cpufreq/cpufreq_userspace.c
*
* Copyright (C) 2001 Russell King
* (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/cpufreq.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
static DEFINE_PER_CPU(unsigned int, cpu_is_managed);
static DEFINE_MUTEX(userspace_mutex);
/**
* 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;
unsigned int *setspeed = policy->governor_data;
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;
*setspeed = freq;
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", policy->cur);
}
static int cpufreq_userspace_policy_init(struct cpufreq_policy *policy)
{
unsigned int *setspeed;
setspeed = kzalloc(sizeof(*setspeed), GFP_KERNEL);
if (!setspeed)
return -ENOMEM;
policy->governor_data = setspeed;
return 0;
}
static void cpufreq_userspace_policy_exit(struct cpufreq_policy *policy)
{
mutex_lock(&userspace_mutex);
kfree(policy->governor_data);
policy->governor_data = NULL;
mutex_unlock(&userspace_mutex);
}
static int cpufreq_userspace_policy_start(struct cpufreq_policy *policy)
{
unsigned int *setspeed = policy->governor_data;
BUG_ON(!policy->cur);
pr_debug("started managing cpu %u\n", policy->cpu);
mutex_lock(&userspace_mutex);
per_cpu(cpu_is_managed, policy->cpu) = 1;
*setspeed = policy->cur;
mutex_unlock(&userspace_mutex);
return 0;
}
static void cpufreq_userspace_policy_stop(struct cpufreq_policy *policy)
{
unsigned int *setspeed = policy->governor_data;
pr_debug("managing cpu %u stopped\n", policy->cpu);
mutex_lock(&userspace_mutex);
per_cpu(cpu_is_managed, policy->cpu) = 0;
*setspeed = 0;
mutex_unlock(&userspace_mutex);
}
static void cpufreq_userspace_policy_limits(struct cpufreq_policy *policy)
{
unsigned int *setspeed = policy->governor_data;
mutex_lock(&userspace_mutex);
pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n",
policy->cpu, policy->min, policy->max, policy->cur, *setspeed);
if (policy->max < *setspeed)
__cpufreq_driver_target(policy, policy->max, CPUFREQ_RELATION_H);
else if (policy->min > *setspeed)
__cpufreq_driver_target(policy, policy->min, CPUFREQ_RELATION_L);
else
__cpufreq_driver_target(policy, *setspeed, CPUFREQ_RELATION_L);
mutex_unlock(&userspace_mutex);
}
static struct cpufreq_governor cpufreq_gov_userspace = {
.name = "userspace",
.init = cpufreq_userspace_policy_init,
.exit = cpufreq_userspace_policy_exit,
.start = cpufreq_userspace_policy_start,
.stop = cpufreq_userspace_policy_stop,
.limits = cpufreq_userspace_policy_limits,
.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
struct cpufreq_governor *cpufreq_default_governor(void)
{
return &cpufreq_gov_userspace;
}
core_initcall(cpufreq_gov_userspace_init);
#else
module_init(cpufreq_gov_userspace_init);
#endif
module_exit(cpufreq_gov_userspace_exit);
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