drivers/cpufreq/freq_table.c

   1 /*
   2  * linux/drivers/cpufreq/freq_table.c
   3  *
   4  * Copyright (C) 2002 - 2003 Dominik Brodowski
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/cpufreq.h>
  15 #include <linux/module.h>
  16
  17 /*********************************************************************
  18  *                     FREQUENCY TABLE HELPERS                       *
  19  *********************************************************************/
  20
  21 int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
  22                                     struct cpufreq_frequency_table *table)
  23 {
  24         unsigned int min_freq = ~0;
  25         unsigned int max_freq = 0;
  26         unsigned int i;
  27
  28         for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
  29                 unsigned int freq = table[i].frequency;
  30                 if (freq == CPUFREQ_ENTRY_INVALID) {
  31                         pr_debug("table entry %u is invalid, skipping\n", i);
  32
  33                         continue;
  34                 }
  35                 pr_debug("table entry %u: %u kHz, %u driver_data\n",
  36                                         i, freq, table[i].driver_data);
  37                 if (freq < min_freq)
  38                         min_freq = freq;
  39                 if (freq > max_freq)
  40                         max_freq = freq;
  41         }
  42
  43         policy->min = policy->cpuinfo.min_freq = min_freq;
  44         policy->max = policy->cpuinfo.max_freq = max_freq;
  45
  46         if (policy->min == ~0)
  47                 return -EINVAL;
  48         else
  49                 return 0;
  50 }
  51 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_cpuinfo);
  52
  53
  54 int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
  55                                    struct cpufreq_frequency_table *table)
  56 {
  57         unsigned int next_larger = ~0, freq, i = 0;
  58         bool found = false;
  59
  60         pr_debug("request for verification of policy (%u - %u kHz) for cpu %u\n",
  61                                         policy->min, policy->max, policy->cpu);
  62
  63         cpufreq_verify_within_cpu_limits(policy);
  64
  65         for (; freq = table[i].frequency, freq != CPUFREQ_TABLE_END; i++) {
  66                 if (freq == CPUFREQ_ENTRY_INVALID)
  67                         continue;
  68                 if ((freq >= policy->min) && (freq <= policy->max)) {
  69                         found = true;
  70                         break;
  71                 }
  72
  73                 if ((next_larger > freq) && (freq > policy->max))
  74                         next_larger = freq;
  75         }
  76
  77         if (!found) {
  78                 policy->max = next_larger;
  79                 cpufreq_verify_within_cpu_limits(policy);
  80         }
  81
  82         pr_debug("verification lead to (%u - %u kHz) for cpu %u\n",
  83                                 policy->min, policy->max, policy->cpu);
  84
  85         return 0;
  86 }
  87 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_verify);
  88
  89
  90 int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
  91                                    struct cpufreq_frequency_table *table,
  92                                    unsigned int target_freq,
  93                                    unsigned int relation,
  94                                    unsigned int *index)
  95 {
  96         struct cpufreq_frequency_table optimal = {
  97                 .driver_data = ~0,
  98                 .frequency = 0,
  99         };
 100         struct cpufreq_frequency_table suboptimal = {
 101                 .driver_data = ~0,
 102                 .frequency = 0,
 103         };
 104         unsigned int i;
 105
 106         pr_debug("request for target %u kHz (relation: %u) for cpu %u\n",
 107                                         target_freq, relation, policy->cpu);
 108
 109         switch (relation) {
 110         case CPUFREQ_RELATION_H:
 111                 suboptimal.frequency = ~0;
 112                 break;
 113         case CPUFREQ_RELATION_L:
 114                 optimal.frequency = ~0;
 115                 break;
 116         }
 117
 118         for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
 119                 unsigned int freq = table[i].frequency;
 120                 if (freq == CPUFREQ_ENTRY_INVALID)
 121                         continue;
 122                 if ((freq < policy->min) || (freq > policy->max))
 123                         continue;
 124                 switch (relation) {
 125                 case CPUFREQ_RELATION_H:
 126                         if (freq <= target_freq) {
 127                                 if (freq >= optimal.frequency) {
 128                                         optimal.frequency = freq;
 129                                         optimal.driver_data = i;
 130                                 }
 131                         } else {
 132                                 if (freq <= suboptimal.frequency) {
 133                                         suboptimal.frequency = freq;
 134                                         suboptimal.driver_data = i;
 135                                 }
 136                         }
 137                         break;
 138                 case CPUFREQ_RELATION_L:
 139                         if (freq >= target_freq) {
 140                                 if (freq <= optimal.frequency) {
 141                                         optimal.frequency = freq;
 142                                         optimal.driver_data = i;
 143                                 }
 144                         } else {
 145                                 if (freq >= suboptimal.frequency) {
 146                                         suboptimal.frequency = freq;
 147                                         suboptimal.driver_data = i;
 148                                 }
 149                         }
 150                         break;
 151                 }
 152         }
 153         if (optimal.driver_data > i) {
 154                 if (suboptimal.driver_data > i)
 155                         return -EINVAL;
 156                 *index = suboptimal.driver_data;
 157         } else
 158                 *index = optimal.driver_data;
 159
 160         pr_debug("target is %u (%u kHz, %u)\n", *index, table[*index].frequency,
 161                 table[*index].driver_data);
 162
 163         return 0;
 164 }
 165 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);
 166
 167 static DEFINE_PER_CPU(struct cpufreq_frequency_table *, cpufreq_show_table);
 168 /**
 169  * show_available_freqs - show available frequencies for the specified CPU
 170  */
 171 static ssize_t show_available_freqs(struct cpufreq_policy *policy, char *buf)
 172 {
 173         unsigned int i = 0;
 174         unsigned int cpu = policy->cpu;
 175         ssize_t count = 0;
 176         struct cpufreq_frequency_table *table;
 177
 178         if (!per_cpu(cpufreq_show_table, cpu))
 179                 return -ENODEV;
 180
 181         table = per_cpu(cpufreq_show_table, cpu);
 182
 183         for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
 184                 if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
 185                         continue;
 186                 count += sprintf(&buf[count], "%d ", table[i].frequency);
 187         }
 188         count += sprintf(&buf[count], "\n");
 189
 190         return count;
 191
 192 }
 193
 194 struct freq_attr cpufreq_freq_attr_scaling_available_freqs = {
 195         .attr = { .name = "scaling_available_frequencies",
 196                   .mode = 0444,
 197                 },
 198         .show = show_available_freqs,
 199 };
 200 EXPORT_SYMBOL_GPL(cpufreq_freq_attr_scaling_available_freqs);
 201
 202 /*
 203  * if you use these, you must assure that the frequency table is valid
 204  * all the time between get_attr and put_attr!
 205  */
 206 void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
 207                                       unsigned int cpu)
 208 {
 209         pr_debug("setting show_table for cpu %u to %p\n", cpu, table);
 210         per_cpu(cpufreq_show_table, cpu) = table;
 211 }
 212 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_attr);
 213
 214 void cpufreq_frequency_table_put_attr(unsigned int cpu)
 215 {
 216         pr_debug("clearing show_table for cpu %u\n", cpu);
 217         per_cpu(cpufreq_show_table, cpu) = NULL;
 218 }
 219 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_put_attr);
 220
 221 int cpufreq_table_validate_and_show(struct cpufreq_policy *policy,
 222                                       struct cpufreq_frequency_table *table)
 223 {
 224         int ret = cpufreq_frequency_table_cpuinfo(policy, table);
 225
 226         if (!ret)
 227                 cpufreq_frequency_table_get_attr(table, policy->cpu);
 228
 229         return ret;
 230 }
 231 EXPORT_SYMBOL_GPL(cpufreq_table_validate_and_show);
 232
 233 void cpufreq_frequency_table_update_policy_cpu(struct cpufreq_policy *policy)
 234 {
 235         pr_debug("Updating show_table for new_cpu %u from last_cpu %u\n",
 236                         policy->cpu, policy->last_cpu);
 237         per_cpu(cpufreq_show_table, policy->cpu) = per_cpu(cpufreq_show_table,
 238                         policy->last_cpu);
 239         per_cpu(cpufreq_show_table, policy->last_cpu) = NULL;
 240 }
 241
 242 struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu)
 243 {
 244         return per_cpu(cpufreq_show_table, cpu);
 245 }
 246 EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table);
 247
 248 MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
 249 MODULE_DESCRIPTION("CPUfreq frequency table helpers");
 250 MODULE_LICENSE("GPL");