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