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![Shaokun Zhang](/assets/img/avatar_default.png)
Local variable 'count' will be initialized and 'ret' is also not required, so remove the redundant initialization and get rid of 'ret'. Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
290 lines
7.1 KiB
C
290 lines
7.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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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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#include <linux/cpu.h>
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#include <linux/cpufreq.h>
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#include <linux/module.h>
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#include <linux/sched/clock.h>
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#include <linux/slab.h>
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struct cpufreq_stats {
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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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unsigned int *trans_table;
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/* Deferred reset */
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unsigned int reset_pending;
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unsigned long long reset_time;
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};
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static void cpufreq_stats_update(struct cpufreq_stats *stats,
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unsigned long long time)
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{
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unsigned long long cur_time = local_clock();
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stats->time_in_state[stats->last_index] += cur_time - time;
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stats->last_time = cur_time;
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}
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static void cpufreq_stats_reset_table(struct cpufreq_stats *stats)
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{
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unsigned int count = stats->max_state;
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memset(stats->time_in_state, 0, count * sizeof(u64));
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memset(stats->trans_table, 0, count * count * sizeof(int));
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stats->last_time = local_clock();
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stats->total_trans = 0;
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/* Adjust for the time elapsed since reset was requested */
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WRITE_ONCE(stats->reset_pending, 0);
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/*
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* Prevent the reset_time read from being reordered before the
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* reset_pending accesses in cpufreq_stats_record_transition().
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*/
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smp_rmb();
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cpufreq_stats_update(stats, READ_ONCE(stats->reset_time));
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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 *stats = policy->stats;
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if (READ_ONCE(stats->reset_pending))
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return sprintf(buf, "%d\n", 0);
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else
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return sprintf(buf, "%u\n", stats->total_trans);
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}
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cpufreq_freq_attr_ro(total_trans);
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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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struct cpufreq_stats *stats = policy->stats;
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bool pending = READ_ONCE(stats->reset_pending);
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unsigned long long time;
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ssize_t len = 0;
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int i;
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for (i = 0; i < stats->state_num; i++) {
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if (pending) {
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if (i == stats->last_index) {
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/*
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* Prevent the reset_time read from occurring
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* before the reset_pending read above.
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*/
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smp_rmb();
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time = local_clock() - READ_ONCE(stats->reset_time);
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} else {
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time = 0;
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}
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} else {
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time = stats->time_in_state[i];
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if (i == stats->last_index)
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time += local_clock() - stats->last_time;
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}
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len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],
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nsec_to_clock_t(time));
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}
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return len;
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}
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cpufreq_freq_attr_ro(time_in_state);
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/* We don't care what is written to the attribute */
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static ssize_t store_reset(struct cpufreq_policy *policy, const char *buf,
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size_t count)
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{
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struct cpufreq_stats *stats = policy->stats;
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/*
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* Defer resetting of stats to cpufreq_stats_record_transition() to
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* avoid races.
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*/
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WRITE_ONCE(stats->reset_time, local_clock());
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/*
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* The memory barrier below is to prevent the readers of reset_time from
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* seeing a stale or partially updated value.
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*/
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smp_wmb();
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WRITE_ONCE(stats->reset_pending, 1);
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return count;
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}
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cpufreq_freq_attr_wo(reset);
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static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
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{
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struct cpufreq_stats *stats = policy->stats;
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bool pending = READ_ONCE(stats->reset_pending);
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ssize_t len = 0;
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int i, j, count;
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len += scnprintf(buf + len, PAGE_SIZE - len, " From : To\n");
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len += scnprintf(buf + len, PAGE_SIZE - len, " : ");
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for (i = 0; i < stats->state_num; i++) {
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if (len >= PAGE_SIZE)
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break;
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len += scnprintf(buf + len, PAGE_SIZE - len, "%9u ",
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stats->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 += scnprintf(buf + len, PAGE_SIZE - len, "\n");
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for (i = 0; i < stats->state_num; i++) {
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if (len >= PAGE_SIZE)
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break;
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len += scnprintf(buf + len, PAGE_SIZE - len, "%9u: ",
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stats->freq_table[i]);
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for (j = 0; j < stats->state_num; j++) {
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if (len >= PAGE_SIZE)
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break;
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if (pending)
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count = 0;
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else
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count = stats->trans_table[i * stats->max_state + j];
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len += scnprintf(buf + len, PAGE_SIZE - len, "%9u ", count);
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}
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if (len >= PAGE_SIZE)
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break;
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len += scnprintf(buf + len, PAGE_SIZE - len, "\n");
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}
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if (len >= PAGE_SIZE) {
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pr_warn_once("cpufreq transition table exceeds PAGE_SIZE. Disabling\n");
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return -EFBIG;
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}
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return len;
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}
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cpufreq_freq_attr_ro(trans_table);
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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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&reset.attr,
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&trans_table.attr,
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NULL
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};
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static const 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 *stats, unsigned int freq)
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{
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int index;
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for (index = 0; index < stats->max_state; index++)
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if (stats->freq_table[index] == freq)
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return index;
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return -1;
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}
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void cpufreq_stats_free_table(struct cpufreq_policy *policy)
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{
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struct cpufreq_stats *stats = policy->stats;
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/* Already freed */
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if (!stats)
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return;
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pr_debug("%s: Free stats table\n", __func__);
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sysfs_remove_group(&policy->kobj, &stats_attr_group);
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kfree(stats->time_in_state);
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kfree(stats);
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policy->stats = NULL;
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}
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void cpufreq_stats_create_table(struct cpufreq_policy *policy)
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{
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unsigned int i = 0, count;
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struct cpufreq_stats *stats;
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unsigned int alloc_size;
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struct cpufreq_frequency_table *pos;
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count = cpufreq_table_count_valid_entries(policy);
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if (!count)
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return;
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/* stats already initialized */
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if (policy->stats)
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return;
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stats = kzalloc(sizeof(*stats), GFP_KERNEL);
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if (!stats)
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return;
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alloc_size = count * sizeof(int) + count * sizeof(u64);
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alloc_size += count * count * sizeof(int);
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/* Allocate memory for time_in_state/freq_table/trans_table in one go */
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stats->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
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if (!stats->time_in_state)
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goto free_stat;
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stats->freq_table = (unsigned int *)(stats->time_in_state + count);
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stats->trans_table = stats->freq_table + count;
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stats->max_state = count;
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/* Find valid-unique entries */
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cpufreq_for_each_valid_entry(pos, policy->freq_table)
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if (freq_table_get_index(stats, pos->frequency) == -1)
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stats->freq_table[i++] = pos->frequency;
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stats->state_num = i;
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stats->last_time = local_clock();
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stats->last_index = freq_table_get_index(stats, policy->cur);
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policy->stats = stats;
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if (!sysfs_create_group(&policy->kobj, &stats_attr_group))
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return;
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/* We failed, release resources */
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policy->stats = NULL;
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kfree(stats->time_in_state);
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free_stat:
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kfree(stats);
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}
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void cpufreq_stats_record_transition(struct cpufreq_policy *policy,
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unsigned int new_freq)
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{
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struct cpufreq_stats *stats = policy->stats;
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int old_index, new_index;
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if (unlikely(!stats))
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return;
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if (unlikely(READ_ONCE(stats->reset_pending)))
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cpufreq_stats_reset_table(stats);
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old_index = stats->last_index;
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new_index = freq_table_get_index(stats, new_freq);
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/* We can't do stats->time_in_state[-1]= .. */
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if (unlikely(old_index == -1 || new_index == -1 || old_index == new_index))
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return;
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cpufreq_stats_update(stats, stats->last_time);
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stats->last_index = new_index;
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stats->trans_table[old_index * stats->max_state + new_index]++;
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stats->total_trans++;
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}
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