linux-imx

​

/*

 *  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/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;