drivers/cpufreq/cpufreq_stats.c

   1 /*
   2  *  drivers/cpufreq/cpufreq_stats.c
   3  *
   4  *  Copyright (C) 2003-2004 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
   5  *  (C) 2004 Zou Nan hai <nanhai.zou@intel.com>.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/cpu.h>
  13 #include <linux/cpufreq.h>
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16
  17 static DEFINE_SPINLOCK(cpufreq_stats_lock);
  18
  19 struct cpufreq_stats {
  20         unsigned int total_trans;
  21         unsigned long long last_time;
  22         unsigned int max_state;
  23         unsigned int state_num;
  24         unsigned int last_index;
  25         u64 *time_in_state;
  26         unsigned int *freq_table;
  27         unsigned int *trans_table;
  28 };
  29
  30 static int cpufreq_stats_update(struct cpufreq_stats *stats)
  31 {
  32         unsigned long long cur_time = get_jiffies_64();
  33
  34         spin_lock(&cpufreq_stats_lock);
  35         stats->time_in_state[stats->last_index] += cur_time - stats->last_time;
  36         stats->last_time = cur_time;
  37         spin_unlock(&cpufreq_stats_lock);
  38         return 0;
  39 }
  40
  41 static void cpufreq_stats_clear_table(struct cpufreq_stats *stats)
  42 {
  43         unsigned int count = stats->max_state;
  44
  45         memset(stats->time_in_state, 0, count * sizeof(u64));
  46         memset(stats->trans_table, 0, count * count * sizeof(int));
  47         stats->last_time = get_jiffies_64();
  48         stats->total_trans = 0;
  49 }
  50
  51 static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
  52 {
  53         return sprintf(buf, "%d\n", policy->stats->total_trans);
  54 }
  55
  56 static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
  57 {
  58         struct cpufreq_stats *stats = policy->stats;
  59         ssize_t len = 0;
  60         int i;
  61
  62         if (policy->fast_switch_enabled)
  63                 return 0;
  64
  65         cpufreq_stats_update(stats);
  66         for (i = 0; i < stats->state_num; i++) {
  67                 len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],
  68                         (unsigned long long)
  69                         jiffies_64_to_clock_t(stats->time_in_state[i]));
  70         }
  71         return len;
  72 }
  73
  74 static ssize_t store_reset(struct cpufreq_policy *policy, const char *buf,
  75                            size_t count)
  76 {
  77         /* We don't care what is written to the attribute. */
  78         cpufreq_stats_clear_table(policy->stats);
  79         return count;
  80 }
  81
  82 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
  83 {
  84         struct cpufreq_stats *stats = policy->stats;
  85         ssize_t len = 0;
  86         int i, j;
  87
  88         if (policy->fast_switch_enabled)
  89                 return 0;
  90
  91         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
  92         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
  93         for (i = 0; i < stats->state_num; i++) {
  94                 if (len >= PAGE_SIZE)
  95                         break;
  96                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
  97                                 stats->freq_table[i]);
  98         }
  99         if (len >= PAGE_SIZE)
 100                 return PAGE_SIZE;
 101
 102         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 103
 104         for (i = 0; i < stats->state_num; i++) {
 105                 if (len >= PAGE_SIZE)
 106                         break;
 107
 108                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
 109                                 stats->freq_table[i]);
 110
 111                 for (j = 0; j < stats->state_num; j++) {
 112                         if (len >= PAGE_SIZE)
 113                                 break;
 114                         len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 115                                         stats->trans_table[i*stats->max_state+j]);
 116                 }
 117                 if (len >= PAGE_SIZE)
 118                         break;
 119                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 120         }
 121
 122         if (len >= PAGE_SIZE) {
 123                 pr_warn_once("cpufreq transition table exceeds PAGE_SIZE. Disabling\n");
 124                 return -EFBIG;
 125         }
 126         return len;
 127 }
 128 cpufreq_freq_attr_ro(trans_table);
 129
 130 cpufreq_freq_attr_ro(total_trans);
 131 cpufreq_freq_attr_ro(time_in_state);
 132 cpufreq_freq_attr_wo(reset);
 133
 134 static struct attribute *default_attrs[] = {
 135         &total_trans.attr,
 136         &time_in_state.attr,
 137         &reset.attr,
 138         &trans_table.attr,
 139         NULL
 140 };
 141 static const struct attribute_group stats_attr_group = {
 142         .attrs = default_attrs,
 143         .name = "stats"
 144 };
 145
 146 static int freq_table_get_index(struct cpufreq_stats *stats, unsigned int freq)
 147 {
 148         int index;
 149         for (index = 0; index < stats->max_state; index++)
 150                 if (stats->freq_table[index] == freq)
 151                         return index;
 152         return -1;
 153 }
 154
 155 void cpufreq_stats_free_table(struct cpufreq_policy *policy)
 156 {
 157         struct cpufreq_stats *stats = policy->stats;
 158
 159         /* Already freed */
 160         if (!stats)
 161                 return;
 162
 163         pr_debug("%s: Free stats table\n", __func__);
 164
 165         sysfs_remove_group(&policy->kobj, &stats_attr_group);
 166         kfree(stats->time_in_state);
 167         kfree(stats);
 168         policy->stats = NULL;
 169 }
 170
 171 void cpufreq_stats_create_table(struct cpufreq_policy *policy)
 172 {
 173         unsigned int i = 0, count = 0, ret = -ENOMEM;
 174         struct cpufreq_stats *stats;
 175         unsigned int alloc_size;
 176         struct cpufreq_frequency_table *pos;
 177
 178         count = cpufreq_table_count_valid_entries(policy);
 179         if (!count)
 180                 return;
 181
 182         /* stats already initialized */
 183         if (policy->stats)
 184                 return;
 185
 186         stats = kzalloc(sizeof(*stats), GFP_KERNEL);
 187         if (!stats)
 188                 return;
 189
 190         alloc_size = count * sizeof(int) + count * sizeof(u64);
 191
 192         alloc_size += count * count * sizeof(int);
 193
 194         /* Allocate memory for time_in_state/freq_table/trans_table in one go */
 195         stats->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 196         if (!stats->time_in_state)
 197                 goto free_stat;
 198
 199         stats->freq_table = (unsigned int *)(stats->time_in_state + count);
 200
 201         stats->trans_table = stats->freq_table + count;
 202
 203         stats->max_state = count;
 204
 205         /* Find valid-unique entries */
 206         cpufreq_for_each_valid_entry(pos, policy->freq_table)
 207                 if (freq_table_get_index(stats, pos->frequency) == -1)
 208                         stats->freq_table[i++] = pos->frequency;
 209
 210         stats->state_num = i;
 211         stats->last_time = get_jiffies_64();
 212         stats->last_index = freq_table_get_index(stats, policy->cur);
 213
 214         policy->stats = stats;
 215         ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
 216         if (!ret)
 217                 return;
 218
 219         /* We failed, release resources */
 220         policy->stats = NULL;
 221         kfree(stats->time_in_state);
 222 free_stat:
 223         kfree(stats);
 224 }
 225
 226 void cpufreq_stats_record_transition(struct cpufreq_policy *policy,
 227                                      unsigned int new_freq)
 228 {
 229         struct cpufreq_stats *stats = policy->stats;
 230         int old_index, new_index;
 231
 232         if (!stats) {
 233                 pr_debug("%s: No stats found\n", __func__);
 234                 return;
 235         }
 236
 237         old_index = stats->last_index;
 238         new_index = freq_table_get_index(stats, new_freq);
 239
 240         /* We can't do stats->time_in_state[-1]= .. */
 241         if (old_index == -1 || new_index == -1 || old_index == new_index)
 242                 return;
 243
 244         cpufreq_stats_update(stats);
 245
 246         stats->last_index = new_index;
 247         stats->trans_table[old_index * stats->max_state + new_index]++;
 248         stats->total_trans++;
 249 }