linux-kernel-cpufreq_stats.c

/*
 *  drivers/cpufreq/cpufreq_stats.c
 *
 *  Copyright (C) 2003-2004 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
 *  (C) 2004 Zou Nan hai <nanhai.zou@intel.com>.
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/cpu.h>
#include <linux/sysfs.h>
#include <linux/cpufreq.h>
#include <linux/module.h>
#include <linux/jiffies.h>
#include <linux/percpu.h>
#include <linux/kobject.h>
#include <linux/spinlock.h>
#include <linux/notifier.h>
#include <asm/cputime.h>
#ifdef CONFIG_BL_SWITCHER
#include <asm/bL_switcher.h>
#endif

static spinlock_t cpufreq_stats_lock;

struct cpufreq_stats {
 unsigned int cpu;
 unsigned int total_trans;
 unsigned long long  last_time;
 unsigned int max_state;
 unsigned int state_num;
 unsigned int last_index;
 u64 *time_in_state;
 unsigned int *freq_table;
#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 unsigned int *trans_table;
#endif
};

static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);

struct cpufreq_stats_attribute {
 struct attribute attr;
 ssize_t(*show) (struct cpufreq_stats *, char *);
};

static int cpufreq_stats_update(unsigned int cpu)
{
 struct cpufreq_stats *stat;
 unsigned long long cur_time;

 cur_time = get_jiffies_64();
 spin_lock(&cpufreq_stats_lock);
 stat = per_cpu(cpufreq_stats_table, cpu);
 if (stat->time_in_state)
  stat->time_in_state[stat->last_index] +=
   cur_time - stat->last_time;
 stat->last_time = cur_time;
 spin_unlock(&cpufreq_stats_lock);
 return 0;
}

static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
{
 struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
 if (!stat)
  return 0;
 return sprintf(buf, "%d\n",
   per_cpu(cpufreq_stats_table, stat->cpu)->total_trans);
}

static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
{
 ssize_t len = 0;
 int i;
 struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
 if (!stat)
  return 0;
 cpufreq_stats_update(stat->cpu);
 for (i = 0; i < stat->state_num; i++) {
  len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
   (unsigned long long)
   cputime64_to_clock_t(stat->time_in_state[i]));
 }
 return len;
}

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
{
 ssize_t len = 0;
 int i, j;

 struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
 if (!stat)
  return 0;
 cpufreq_stats_update(stat->cpu);
 len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
 len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
 for (i = 0; i < stat->state_num; i++) {
  if (len >= PAGE_SIZE)
   break;
  len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
    stat->freq_table[i]);
 }
 if (len >= PAGE_SIZE)
  return PAGE_SIZE;

 len += snprintf(buf + len, PAGE_SIZE - len, "\n");

 for (i = 0; i < stat->state_num; i++) {
  if (len >= PAGE_SIZE)
   break;

  len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
    stat->freq_table[i]);

  for (j = 0; j < stat->state_num; j++)   {
   if (len >= PAGE_SIZE)
    break;
   len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
     stat->trans_table[i*stat->max_state+j]);
  }
  if (len >= PAGE_SIZE)
   break;
  len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 }
 if (len >= PAGE_SIZE)
  return PAGE_SIZE;
 return len;
}
cpufreq_freq_attr_ro(trans_table);
#endif

cpufreq_freq_attr_ro(total_trans);
cpufreq_freq_attr_ro(time_in_state);

static struct attribute *default_attrs[] = {
 &total_trans.attr,
 &time_in_state.attr,
#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 &trans_table.attr,
#endif
 NULL
};
static struct attribute_group stats_attr_group = {
 .attrs = default_attrs,
 .name = "stats"
};

static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
{
 int index;
 for (index = 0; index < stat->max_state; index++)
  if (stat->freq_table[index] == freq)
   return index;
#if defined CONFIG_HISI_3635_FPGA
 return 0;
#endif
 return -1;
}

/* should be called late in the CPU removal sequence so that the stats
 * memory is still available in case someone tries to use it.
 */
static void cpufreq_stats_free_table(unsigned int cpu)
{
 struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);

 if (stat) {
  pr_debug("%s: Free stat table\n", __func__);
  kfree(stat->time_in_state);
  kfree(stat);
  per_cpu(cpufreq_stats_table, cpu) = NULL;
 }
}

/* must be called early in the CPU removal sequence (before
 * cpufreq_remove_dev) so that policy is still valid.
 */
static void cpufreq_stats_free_sysfs(unsigned int cpu)
{
 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);

 if (!policy)
  return;

 if (!cpufreq_frequency_get_table(cpu))
  goto put_ref;

 if (!policy_is_shared(policy)) {
  pr_debug("%s: Free sysfs stat\n", __func__);
  sysfs_remove_group(&policy->kobj, &stats_attr_group);
 }

put_ref:
 cpufreq_cpu_put(policy);
}

static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
  struct cpufreq_frequency_table *table)
{
 unsigned int i, j, count = 0, ret = 0;
 struct cpufreq_stats *stat;
 struct cpufreq_policy *data;
 unsigned int alloc_size;
 unsigned int cpu = policy->cpu;
 if (per_cpu(cpufreq_stats_table, cpu))
  return -EBUSY;
 stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL);
 if ((stat) == NULL)
  return -ENOMEM;

 data = cpufreq_cpu_get(cpu);
 if (data == NULL) {
  ret = -EINVAL;
  goto error_get_fail;
 }

 ret = sysfs_create_group(&data->kobj, &stats_attr_group);
 if (ret)
  goto error_out;

 stat->cpu = cpu;
 per_cpu(cpufreq_stats_table, cpu) = stat;

 for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
  unsigned int freq = table[i].frequency;
  if (freq == CPUFREQ_ENTRY_INVALID)
   continue;
  count++;
 }

 alloc_size = count * sizeof(int) + count * sizeof(u64);

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 alloc_size += count * count * sizeof(int);
#endif
 stat->max_state = count;
 stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 if (!stat->time_in_state) {
  ret = -ENOMEM;
  goto error_out;
 }
 stat->freq_table = (unsigned int *)(stat->time_in_state + count);

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 stat->trans_table = stat->freq_table + count;
#endif
 j = 0;
 for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
  unsigned int freq = table[i].frequency;
  if (freq == CPUFREQ_ENTRY_INVALID)
   continue;
  if (freq_table_get_index(stat, freq) == -1)
   stat->freq_table[j++] = freq;
 }
 stat->state_num = j;
 spin_lock(&cpufreq_stats_lock);
 stat->last_time = get_jiffies_64();
 stat->last_index = freq_table_get_index(stat, policy->cur);
 spin_unlock(&cpufreq_stats_lock);
 cpufreq_cpu_put(data);
 return 0;
error_out:
 cpufreq_cpu_put(data);
error_get_fail:
 kfree(stat);
 per_cpu(cpufreq_stats_table, cpu) = NULL;
 return ret;
}

static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)
{
 struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table,
   policy->last_cpu);

 pr_debug("Updating stats_table for new_cpu %u from last_cpu %u\n",
   policy->cpu, policy->last_cpu);
 per_cpu(cpufreq_stats_table, policy->cpu) = per_cpu(cpufreq_stats_table,
   policy->last_cpu);
 per_cpu(cpufreq_stats_table, policy->last_cpu) = NULL;
 stat->cpu = policy->cpu;
}

static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
  unsigned long val, void *data)
{
 int ret;
 struct cpufreq_policy *policy = data;
 struct cpufreq_frequency_table *table;
 unsigned int cpu = policy->cpu;

 if (val == CPUFREQ_UPDATE_POLICY_CPU) {
  cpufreq_stats_update_policy_cpu(policy);
  return 0;
 }

 if (val != CPUFREQ_NOTIFY)
  return 0;
 table = cpufreq_frequency_get_table(cpu);
 if (!table)
  return 0;
 ret = cpufreq_stats_create_table(policy, table);
 if (ret)
  return ret;
 return 0;
}

static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
  unsigned long val, void *data)
{
 struct cpufreq_freqs *freq = data;
 struct cpufreq_stats *stat;
 int old_index, new_index;

 if (val != CPUFREQ_POSTCHANGE)
  return 0;

 stat = per_cpu(cpufreq_stats_table, freq->cpu);
 if (!stat)
  return 0;

 old_index = stat->last_index;
 new_index = freq_table_get_index(stat, freq->new);

 /* We can't do stat->time_in_state[-1]= .. */
 if (old_index == -1 || new_index == -1)
  return 0;

 cpufreq_stats_update(freq->cpu);

 if (old_index == new_index)
  return 0;

 spin_lock(&cpufreq_stats_lock);
 stat->last_index = new_index;
#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 stat->trans_table[old_index * stat->max_state + new_index]++;
#endif
 stat->total_trans++;
 spin_unlock(&cpufreq_stats_lock);
 return 0;
}

static int cpufreq_stats_create_table_cpu(unsigned int cpu)
{
 struct cpufreq_policy *policy;
 struct cpufreq_frequency_table *table;
 int ret = -ENODEV;

 policy = cpufreq_cpu_get(cpu);
 if (!policy)
  return -ENODEV;

 table = cpufreq_frequency_get_table(cpu);
 if (!table)
  goto out;

 ret = cpufreq_stats_create_table(policy, table);

out:
 cpufreq_cpu_put(policy);
 return ret;
}

static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
            unsigned long action,
            void *hcpu)
{
 unsigned int cpu = (unsigned long)hcpu;

 switch (action) {
 case CPU_ONLINE:
 case CPU_ONLINE_FROZEN:
  cpufreq_update_policy(cpu);
  break;
 case CPU_DOWN_PREPARE:
 case CPU_DOWN_PREPARE_FROZEN:
  cpufreq_stats_free_sysfs(cpu);
  break;
 case CPU_DEAD:
 case CPU_DEAD_FROZEN:
  cpufreq_stats_free_table(cpu);
  break;
 case CPU_DOWN_FAILED:
 case CPU_DOWN_FAILED_FROZEN:
  cpufreq_stats_create_table_cpu(cpu);
  break;
 }
 return NOTIFY_OK;
}

/* priority=1 so this will get called before cpufreq_remove_dev */
static struct notifier_block cpufreq_stat_cpu_notifier __refdata = {
 .notifier_call = cpufreq_stat_cpu_callback,
 .priority = 1,
};

static struct notifier_block notifier_policy_block = {
 .notifier_call = cpufreq_stat_notifier_policy
};

static struct notifier_block notifier_trans_block = {
 .notifier_call = cpufreq_stat_notifier_trans
};

static int cpufreq_stats_setup(void)
{
 int ret;
 unsigned int cpu;

 spin_lock_init(&cpufreq_stats_lock);
 ret = cpufreq_register_notifier(&notifier_policy_block,
    CPUFREQ_POLICY_NOTIFIER);
 if (ret)
  return ret;

 register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 for_each_online_cpu(cpu)
  cpufreq_update_policy(cpu);

 ret = cpufreq_register_notifier(&notifier_trans_block,
    CPUFREQ_TRANSITION_NOTIFIER);
 if (ret) {
  cpufreq_unregister_notifier(&notifier_policy_block,
    CPUFREQ_POLICY_NOTIFIER);
  unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
  for_each_online_cpu(cpu)
   cpufreq_stats_free_table(cpu);
  return ret;
 }

 return 0;
}

static void cpufreq_stats_cleanup(void)
{
 unsigned int cpu;

 cpufreq_unregister_notifier(&notifier_policy_block,
   CPUFREQ_POLICY_NOTIFIER);
 cpufreq_unregister_notifier(&notifier_trans_block,
   CPUFREQ_TRANSITION_NOTIFIER);
 unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 for_each_online_cpu(cpu) {
  cpufreq_stats_free_table(cpu);
  cpufreq_stats_free_sysfs(cpu);
 }
}

#ifdef CONFIG_BL_SWITCHER
static int cpufreq_stats_switcher_notifier(struct notifier_block *nfb,
     unsigned long action, void *_arg)
{
 switch (action) {
 case BL_NOTIFY_PRE_ENABLE:
 case BL_NOTIFY_PRE_DISABLE:
  cpufreq_stats_cleanup();
  break;

 case BL_NOTIFY_POST_ENABLE:
 case BL_NOTIFY_POST_DISABLE:
  cpufreq_stats_setup();
  break;

 default:
  return NOTIFY_DONE;
 }

 return NOTIFY_OK;
}

static struct notifier_block switcher_notifier = {
 .notifier_call = cpufreq_stats_switcher_notifier,
};
#endif

static int __init cpufreq_stats_init(void)
{
 int ret;
 spin_lock_init(&cpufreq_stats_lock);

 ret = cpufreq_stats_setup();
#ifdef CONFIG_BL_SWITCHER
 if (!ret)
  bL_switcher_register_notifier(&switcher_notifier);
#endif
 return ret;
}

static void __exit cpufreq_stats_exit(void)
{
#ifdef CONFIG_BL_SWITCHER
 bL_switcher_unregister_notifier(&switcher_notifier);
#endif
 cpufreq_stats_cleanup();
}

MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
    "through sysfs filesystem");
MODULE_LICENSE("GPL");

module_init(cpufreq_stats_init);
module_exit(cpufreq_stats_exit);