![Srivatsa S. Bhat](/assets/img/avatar_default.png)
The file permissions of cpufreq per-cpu sysfs files are not preserved across suspend/resume because we internally go through the CPU Hotplug path which reinitializes the file permissions on CPU online. But the user is not supposed to know that we are using CPU hotplug internally within suspend/resume (IOW, the kernel should not silently wreck the user-set file permissions across a suspend cycle). Therefore, we need to preserve the file permissions as they are across suspend/resume. The simplest way to achieve that is to just not touch the sysfs files at all - ie., just ignore the CPU hotplug notifications in the suspend/resume path (_FROZEN) in the cpufreq hotplug callback. Reported-by: Robert Jarzmik <robert.jarzmik@intel.com> Reported-by: Durgadoss R <durgadoss.r@intel.com> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
432 lines
11 KiB
C
432 lines
11 KiB
C
/*
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* drivers/cpufreq/cpufreq_stats.c
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*
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* Copyright (C) 2003-2004 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
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* (C) 2004 Zou Nan hai <nanhai.zou@intel.com>.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/cpu.h>
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#include <linux/sysfs.h>
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#include <linux/cpufreq.h>
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#include <linux/module.h>
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#include <linux/jiffies.h>
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#include <linux/percpu.h>
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#include <linux/kobject.h>
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#include <linux/spinlock.h>
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#include <linux/notifier.h>
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#include <asm/cputime.h>
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static spinlock_t cpufreq_stats_lock;
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struct cpufreq_stats {
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unsigned int cpu;
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unsigned int total_trans;
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unsigned long long last_time;
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unsigned int max_state;
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unsigned int state_num;
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unsigned int last_index;
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u64 *time_in_state;
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unsigned int *freq_table;
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#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
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unsigned int *trans_table;
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#endif
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};
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static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
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struct cpufreq_stats_attribute {
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struct attribute attr;
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ssize_t(*show) (struct cpufreq_stats *, char *);
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};
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static int cpufreq_stats_update(unsigned int cpu)
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{
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struct cpufreq_stats *stat;
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unsigned long long cur_time;
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cur_time = get_jiffies_64();
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spin_lock(&cpufreq_stats_lock);
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stat = per_cpu(cpufreq_stats_table, cpu);
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if (stat->time_in_state)
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stat->time_in_state[stat->last_index] +=
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cur_time - stat->last_time;
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stat->last_time = cur_time;
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spin_unlock(&cpufreq_stats_lock);
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return 0;
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}
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static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
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{
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struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
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if (!stat)
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return 0;
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return sprintf(buf, "%d\n",
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per_cpu(cpufreq_stats_table, stat->cpu)->total_trans);
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}
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static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
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{
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ssize_t len = 0;
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int i;
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struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
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if (!stat)
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return 0;
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cpufreq_stats_update(stat->cpu);
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for (i = 0; i < stat->state_num; i++) {
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len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
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(unsigned long long)
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cputime64_to_clock_t(stat->time_in_state[i]));
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}
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return len;
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}
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#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
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static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
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{
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ssize_t len = 0;
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int i, j;
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struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
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if (!stat)
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return 0;
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cpufreq_stats_update(stat->cpu);
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len += snprintf(buf + len, PAGE_SIZE - len, " From : To\n");
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len += snprintf(buf + len, PAGE_SIZE - len, " : ");
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for (i = 0; i < stat->state_num; i++) {
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if (len >= PAGE_SIZE)
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break;
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len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
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stat->freq_table[i]);
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}
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if (len >= PAGE_SIZE)
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return PAGE_SIZE;
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len += snprintf(buf + len, PAGE_SIZE - len, "\n");
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for (i = 0; i < stat->state_num; i++) {
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if (len >= PAGE_SIZE)
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break;
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len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
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stat->freq_table[i]);
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for (j = 0; j < stat->state_num; j++) {
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if (len >= PAGE_SIZE)
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break;
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len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
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stat->trans_table[i*stat->max_state+j]);
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}
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if (len >= PAGE_SIZE)
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break;
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len += snprintf(buf + len, PAGE_SIZE - len, "\n");
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}
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if (len >= PAGE_SIZE)
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return PAGE_SIZE;
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return len;
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}
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cpufreq_freq_attr_ro(trans_table);
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#endif
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cpufreq_freq_attr_ro(total_trans);
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cpufreq_freq_attr_ro(time_in_state);
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static struct attribute *default_attrs[] = {
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&total_trans.attr,
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&time_in_state.attr,
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#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
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&trans_table.attr,
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#endif
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NULL
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};
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static struct attribute_group stats_attr_group = {
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.attrs = default_attrs,
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.name = "stats"
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};
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static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
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{
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int index;
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for (index = 0; index < stat->max_state; index++)
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if (stat->freq_table[index] == freq)
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return index;
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return -1;
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}
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/* should be called late in the CPU removal sequence so that the stats
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* memory is still available in case someone tries to use it.
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*/
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static void cpufreq_stats_free_table(unsigned int cpu)
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{
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struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
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if (stat) {
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pr_debug("%s: Free stat table\n", __func__);
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kfree(stat->time_in_state);
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kfree(stat);
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per_cpu(cpufreq_stats_table, cpu) = NULL;
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}
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}
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/* must be called early in the CPU removal sequence (before
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* cpufreq_remove_dev) so that policy is still valid.
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*/
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static void cpufreq_stats_free_sysfs(unsigned int cpu)
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{
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struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
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if (!policy)
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return;
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if (!cpufreq_frequency_get_table(cpu))
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goto put_ref;
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if (!policy_is_shared(policy)) {
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pr_debug("%s: Free sysfs stat\n", __func__);
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sysfs_remove_group(&policy->kobj, &stats_attr_group);
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}
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put_ref:
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cpufreq_cpu_put(policy);
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}
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static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
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struct cpufreq_frequency_table *table)
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{
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unsigned int i, j, count = 0, ret = 0;
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struct cpufreq_stats *stat;
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struct cpufreq_policy *data;
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unsigned int alloc_size;
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unsigned int cpu = policy->cpu;
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if (per_cpu(cpufreq_stats_table, cpu))
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return -EBUSY;
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stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL);
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if ((stat) == NULL)
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return -ENOMEM;
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data = cpufreq_cpu_get(cpu);
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if (data == NULL) {
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ret = -EINVAL;
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goto error_get_fail;
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}
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ret = sysfs_create_group(&data->kobj, &stats_attr_group);
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if (ret)
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goto error_out;
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stat->cpu = cpu;
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per_cpu(cpufreq_stats_table, cpu) = stat;
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for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
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unsigned int freq = table[i].frequency;
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if (freq == CPUFREQ_ENTRY_INVALID)
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continue;
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count++;
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}
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alloc_size = count * sizeof(int) + count * sizeof(u64);
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#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
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alloc_size += count * count * sizeof(int);
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#endif
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stat->max_state = count;
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stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
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if (!stat->time_in_state) {
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ret = -ENOMEM;
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goto error_out;
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}
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stat->freq_table = (unsigned int *)(stat->time_in_state + count);
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#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
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stat->trans_table = stat->freq_table + count;
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#endif
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j = 0;
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for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
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unsigned int freq = table[i].frequency;
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if (freq == CPUFREQ_ENTRY_INVALID)
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continue;
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if (freq_table_get_index(stat, freq) == -1)
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stat->freq_table[j++] = freq;
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}
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stat->state_num = j;
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spin_lock(&cpufreq_stats_lock);
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stat->last_time = get_jiffies_64();
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stat->last_index = freq_table_get_index(stat, policy->cur);
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spin_unlock(&cpufreq_stats_lock);
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cpufreq_cpu_put(data);
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return 0;
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error_out:
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cpufreq_cpu_put(data);
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error_get_fail:
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kfree(stat);
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per_cpu(cpufreq_stats_table, cpu) = NULL;
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return ret;
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}
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static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)
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{
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struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table,
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policy->last_cpu);
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pr_debug("Updating stats_table for new_cpu %u from last_cpu %u\n",
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policy->cpu, policy->last_cpu);
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per_cpu(cpufreq_stats_table, policy->cpu) = per_cpu(cpufreq_stats_table,
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policy->last_cpu);
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per_cpu(cpufreq_stats_table, policy->last_cpu) = NULL;
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stat->cpu = policy->cpu;
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}
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static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
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unsigned long val, void *data)
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{
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int ret;
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struct cpufreq_policy *policy = data;
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struct cpufreq_frequency_table *table;
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unsigned int cpu = policy->cpu;
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if (val == CPUFREQ_UPDATE_POLICY_CPU) {
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cpufreq_stats_update_policy_cpu(policy);
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return 0;
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}
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if (val != CPUFREQ_NOTIFY)
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return 0;
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table = cpufreq_frequency_get_table(cpu);
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if (!table)
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return 0;
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ret = cpufreq_stats_create_table(policy, table);
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if (ret)
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return ret;
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return 0;
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}
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static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
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unsigned long val, void *data)
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{
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struct cpufreq_freqs *freq = data;
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struct cpufreq_stats *stat;
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int old_index, new_index;
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if (val != CPUFREQ_POSTCHANGE)
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return 0;
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stat = per_cpu(cpufreq_stats_table, freq->cpu);
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if (!stat)
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return 0;
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old_index = stat->last_index;
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new_index = freq_table_get_index(stat, freq->new);
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/* We can't do stat->time_in_state[-1]= .. */
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if (old_index == -1 || new_index == -1)
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return 0;
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cpufreq_stats_update(freq->cpu);
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if (old_index == new_index)
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return 0;
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spin_lock(&cpufreq_stats_lock);
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stat->last_index = new_index;
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#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
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stat->trans_table[old_index * stat->max_state + new_index]++;
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#endif
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stat->total_trans++;
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spin_unlock(&cpufreq_stats_lock);
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return 0;
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}
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static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
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unsigned long action,
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void *hcpu)
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{
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unsigned int cpu = (unsigned long)hcpu;
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switch (action) {
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case CPU_ONLINE:
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cpufreq_update_policy(cpu);
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break;
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case CPU_DOWN_PREPARE:
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cpufreq_stats_free_sysfs(cpu);
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break;
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case CPU_DEAD:
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cpufreq_stats_free_table(cpu);
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break;
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case CPU_UP_CANCELED_FROZEN:
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cpufreq_stats_free_sysfs(cpu);
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cpufreq_stats_free_table(cpu);
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break;
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}
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return NOTIFY_OK;
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}
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/* priority=1 so this will get called before cpufreq_remove_dev */
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static struct notifier_block cpufreq_stat_cpu_notifier __refdata = {
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.notifier_call = cpufreq_stat_cpu_callback,
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.priority = 1,
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};
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static struct notifier_block notifier_policy_block = {
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.notifier_call = cpufreq_stat_notifier_policy
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};
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static struct notifier_block notifier_trans_block = {
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.notifier_call = cpufreq_stat_notifier_trans
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};
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static int __init cpufreq_stats_init(void)
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{
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int ret;
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unsigned int cpu;
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spin_lock_init(&cpufreq_stats_lock);
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ret = cpufreq_register_notifier(¬ifier_policy_block,
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CPUFREQ_POLICY_NOTIFIER);
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if (ret)
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return ret;
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register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
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for_each_online_cpu(cpu)
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cpufreq_update_policy(cpu);
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ret = cpufreq_register_notifier(¬ifier_trans_block,
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CPUFREQ_TRANSITION_NOTIFIER);
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if (ret) {
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cpufreq_unregister_notifier(¬ifier_policy_block,
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CPUFREQ_POLICY_NOTIFIER);
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unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
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for_each_online_cpu(cpu)
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cpufreq_stats_free_table(cpu);
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return ret;
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}
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return 0;
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}
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static void __exit cpufreq_stats_exit(void)
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{
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unsigned int cpu;
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cpufreq_unregister_notifier(¬ifier_policy_block,
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CPUFREQ_POLICY_NOTIFIER);
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cpufreq_unregister_notifier(¬ifier_trans_block,
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CPUFREQ_TRANSITION_NOTIFIER);
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unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
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for_each_online_cpu(cpu) {
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cpufreq_stats_free_table(cpu);
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cpufreq_stats_free_sysfs(cpu);
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}
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}
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MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
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MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
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"through sysfs filesystem");
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MODULE_LICENSE("GPL");
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module_init(cpufreq_stats_init);
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module_exit(cpufreq_stats_exit);
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