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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>
struct userspace_policy {
unsigned int is_managed;
unsigned int setspeed;
struct mutex 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;
struct userspace_policy *userspace = policy->governor_data;
pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
mutex_lock(&userspace->mutex);
if (!userspace->is_managed)
goto err;
userspace->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)
{
struct userspace_policy *userspace;
userspace = kzalloc(sizeof(*userspace), GFP_KERNEL);
if (!userspace)
return -ENOMEM;
mutex_init(&userspace->mutex);
policy->governor_data = userspace;
return 0;
}
/*
* Any routine that writes to the policy struct will hold the "rwsem" of
* policy struct that means it is free to free "governor_data" here.
*/
static void cpufreq_userspace_policy_exit(struct cpufreq_policy *policy)
{
kfree(policy->governor_data);
policy->governor_data = NULL;
}
static int cpufreq_userspace_policy_start(struct cpufreq_policy *policy)
{
struct userspace_policy *userspace = policy->governor_data;
BUG_ON(!policy->cur);
pr_debug("started managing cpu %u\n", policy->cpu);
mutex_lock(&userspace->mutex);
userspace->is_managed = 1;
userspace->setspeed = policy->cur;
mutex_unlock(&userspace->mutex);
return 0;
}
static void cpufreq_userspace_policy_stop(struct cpufreq_policy *policy)
{
struct userspace_policy *userspace = policy->governor_data;
pr_debug("managing cpu %u stopped\n", policy->cpu);
mutex_lock(&userspace->mutex);
userspace->is_managed = 0;
userspace->setspeed = 0;
mutex_unlock(&userspace->mutex);
}
static void cpufreq_userspace_policy_limits(struct cpufreq_policy *policy)
{
struct userspace_policy *userspace = 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, userspace->setspeed);
if (policy->max < userspace->setspeed)
__cpufreq_driver_target(policy, policy->max,
CPUFREQ_RELATION_H);
else if (policy->min > userspace->setspeed)
__cpufreq_driver_target(policy, policy->min,
CPUFREQ_RELATION_L);
else
__cpufreq_driver_target(policy, userspace->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,
};
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;
}
#endif
cpufreq_governor_init(cpufreq_gov_userspace);
cpufreq_governor_exit(cpufreq_gov_userspace);
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