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/*
* Copyright (c) 2012, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* TODO:
* Use standard cpufreq APIs to limit CPU min/max frequencies
*
*/
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/module.h>
#include <mach/cpufreq.h>
#define CPUFREQ_LIMIT "cpufreq_limit"
static uint32_t limited_max_freq = MSM_CPUFREQ_NO_LIMIT;
static uint32_t limited_min_freq = MSM_CPUFREQ_NO_LIMIT;
static int update_cpu_freq_limits(unsigned int cpu,
uint32_t min_freq, uint32_t max_freq)
{
int ret;
ret = msm_cpufreq_set_freq_limits(cpu, min_freq, max_freq);
if (ret)
goto err;
ret = cpufreq_update_policy(cpu);
err:
return ret;
}
static ssize_t show_limited_min_freq(struct kobject *kobj,
struct attribute *attr, char *buf)
{
return sprintf(buf, "%u\n", limited_min_freq);
}
static ssize_t store_limited_min_freq(struct kobject *kobj,
struct attribute *attr, const char *buf, size_t count)
{
int ret;
unsigned long new_freq;
uint32_t cpu;
ret = kstrtoul(buf, 0, &new_freq);
if (ret < 0)
return ret;
if (new_freq == 384000)
new_freq = MSM_CPUFREQ_NO_LIMIT;
for_each_possible_cpu(cpu) {
ret = update_cpu_freq_limits(cpu, new_freq, limited_max_freq);
if (ret)
pr_debug("%s: Failed to limit cpu%u min freq to %lu\n",
__func__, cpu, new_freq);
}
limited_min_freq = new_freq;
return count;
}
static struct global_attr limited_min_freq_attr = __ATTR(limited_min_freq,
S_IRUGO | S_IWUSR | S_IWGRP,
show_limited_min_freq,
store_limited_min_freq);
static ssize_t show_limited_max_freq(struct kobject *kobj,
struct attribute *attr, char *buf)
{
return sprintf(buf, "%u\n", limited_max_freq);
}
static ssize_t store_limited_max_freq(struct kobject *kobj,
struct attribute *attr, const char *buf, size_t count)
{
int ret;
unsigned long new_freq;
uint32_t cpu;
ret = kstrtoul(buf, 0, &new_freq);
if (ret < 0)
return ret;
if (new_freq == 1512000)
new_freq = MSM_CPUFREQ_NO_LIMIT;
for_each_possible_cpu(cpu) {
ret = update_cpu_freq_limits(cpu, limited_min_freq, new_freq);
if (ret)
pr_debug("%s: Failed to limit cpu%u max freq to %lu\n",
__func__, cpu, new_freq);
}
limited_max_freq = new_freq;
return count;
}
static struct global_attr limited_max_freq_attr = __ATTR(limited_max_freq,
S_IRUGO | S_IWUSR | S_IWGRP,
show_limited_max_freq,
store_limited_max_freq);
static struct attribute *cpufreq_limit_attributes[] = {
&limited_max_freq_attr.attr,
&limited_min_freq_attr.attr,
NULL
};
static struct attribute_group cpufreq_limit_attr_group = {
.attrs = cpufreq_limit_attributes,
.name = CPUFREQ_LIMIT,
};
static int cpufreq_limit_init(void)
{
int ret;
ret = sysfs_create_group(kernel_kobj, &cpufreq_limit_attr_group);
if (ret)
pr_err("%s: sysfs_creation failed, ret=%d\n", __func__, ret);
return ret;
}
static void cpufreq_limit_exit(void)
{
sysfs_remove_group(kernel_kobj, &cpufreq_limit_attr_group);
}
module_init(cpufreq_limit_init);
module_exit(cpufreq_limit_exit);
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