![Viresh Kumar](/assets/img/avatar_default.png)
With debug options on, it is difficult to locate cpufreq core's debug prints. Fix this by prefixing debug prints with KBUILD_MODNAME. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
225 lines
6 KiB
C
225 lines
6 KiB
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.
|
|
*
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#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;
|
|
|
|
if (val == CPUFREQ_POSTCHANGE) {
|
|
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);
|