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  * Generic routine to verify policy & frequency table, requires driver to call
  91  * cpufreq_frequency_table_get_attr() prior to it.
  92  */
  93 int cpufreq_generic_frequency_table_verify(struct cpufreq_policy *policy)
  94 {
  95         struct cpufreq_frequency_table *table =
  96                 cpufreq_frequency_get_table(policy->cpu);
  97         if (!table)
  98                 return -ENODEV;
  99
 100         return cpufreq_frequency_table_verify(policy, table);
 101 }
 102 EXPORT_SYMBOL_GPL(cpufreq_generic_frequency_table_verify);
 103
 104 int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
 105                                    struct cpufreq_frequency_table *table,
 106                                    unsigned int target_freq,
 107                                    unsigned int relation,
 108                                    unsigned int *index)
 109 {
 110         struct cpufreq_frequency_table optimal = {
 111                 .driver_data = ~0,
 112                 .frequency = 0,
 113         };
 114         struct cpufreq_frequency_table suboptimal = {
 115                 .driver_data = ~0,
 116                 .frequency = 0,
 117         };
 118         unsigned int i;
 119
 120         pr_debug("request for target %u kHz (relation: %u) for cpu %u\n",
 121                                         target_freq, relation, policy->cpu);
 122
 123         switch (relation) {
 124         case CPUFREQ_RELATION_H:
 125                 suboptimal.frequency = ~0;
 126                 break;
 127         case CPUFREQ_RELATION_L:
 128                 optimal.frequency = ~0;
 129                 break;
 130         }
 131
 132         for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
 133                 unsigned int freq = table[i].frequency;
 134                 if (freq == CPUFREQ_ENTRY_INVALID)
 135                         continue;
 136                 if ((freq < policy->min) || (freq > policy->max))
 137                         continue;
 138                 switch (relation) {
 139                 case CPUFREQ_RELATION_H:
 140                         if (freq <= target_freq) {
 141                                 if (freq >= optimal.frequency) {
 142                                         optimal.frequency = freq;
 143                                         optimal.driver_data = i;
 144                                 }
 145                         } else {
 146                                 if (freq <= suboptimal.frequency) {
 147                                         suboptimal.frequency = freq;
 148                                         suboptimal.driver_data = i;
 149                                 }
 150                         }
 151                         break;
 152                 case CPUFREQ_RELATION_L:
 153                         if (freq >= target_freq) {
 154                                 if (freq <= optimal.frequency) {
 155                                         optimal.frequency = freq;
 156                                         optimal.driver_data = i;
 157                                 }
 158                         } else {
 159                                 if (freq >= suboptimal.frequency) {
 160                                         suboptimal.frequency = freq;
 161                                         suboptimal.driver_data = i;
 162                                 }
 163                         }
 164                         break;
 165                 }
 166         }
 167         if (optimal.driver_data > i) {
 168                 if (suboptimal.driver_data > i)
 169                         return -EINVAL;
 170                 *index = suboptimal.driver_data;
 171         } else
 172                 *index = optimal.driver_data;
 173
 174         pr_debug("target is %u (%u kHz, %u)\n", *index, table[*index].frequency,
 175                 table[*index].driver_data);
 176
 177         return 0;
 178 }
 179 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);
 180
 181 static DEFINE_PER_CPU(struct cpufreq_frequency_table *, cpufreq_show_table);
 182 /**
 183  * show_available_freqs - show available frequencies for the specified CPU
 184  */
 185 static ssize_t show_available_freqs(struct cpufreq_policy *policy, char *buf)
 186 {
 187         unsigned int i = 0;
 188         unsigned int cpu = policy->cpu;
 189         ssize_t count = 0;
 190         struct cpufreq_frequency_table *table;
 191
 192         if (!per_cpu(cpufreq_show_table, cpu))
 193                 return -ENODEV;
 194
 195         table = per_cpu(cpufreq_show_table, cpu);
 196
 197         for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
 198                 if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
 199                         continue;
 200                 count += sprintf(&buf[count], "%d ", table[i].frequency);
 201         }
 202         count += sprintf(&buf[count], "\n");
 203
 204         return count;
 205
 206 }
 207
 208 struct freq_attr cpufreq_freq_attr_scaling_available_freqs = {
 209         .attr = { .name = "scaling_available_frequencies",
 210                   .mode = 0444,
 211                 },
 212         .show = show_available_freqs,
 213 };
 214 EXPORT_SYMBOL_GPL(cpufreq_freq_attr_scaling_available_freqs);
 215
 216 struct freq_attr *cpufreq_generic_attr[] = {
 217         &cpufreq_freq_attr_scaling_available_freqs,
 218         NULL,
 219 };
 220 EXPORT_SYMBOL_GPL(cpufreq_generic_attr);
 221
 222 /*
 223  * if you use these, you must assure that the frequency table is valid
 224  * all the time between get_attr and put_attr!
 225  */
 226 void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
 227                                       unsigned int cpu)
 228 {
 229         pr_debug("setting show_table for cpu %u to %p\n", cpu, table);
 230         per_cpu(cpufreq_show_table, cpu) = table;
 231 }
 232 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_attr);
 233
 234 void cpufreq_frequency_table_put_attr(unsigned int cpu)
 235 {
 236         pr_debug("clearing show_table for cpu %u\n", cpu);
 237         per_cpu(cpufreq_show_table, cpu) = NULL;
 238 }
 239 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_put_attr);
 240
 241 int cpufreq_table_validate_and_show(struct cpufreq_policy *policy,
 242                                       struct cpufreq_frequency_table *table)
 243 {
 244         int ret = cpufreq_frequency_table_cpuinfo(policy, table);
 245
 246         if (!ret)
 247                 cpufreq_frequency_table_get_attr(table, policy->cpu);
 248
 249         return ret;
 250 }
 251 EXPORT_SYMBOL_GPL(cpufreq_table_validate_and_show);
 252
 253 void cpufreq_frequency_table_update_policy_cpu(struct cpufreq_policy *policy)
 254 {
 255         pr_debug("Updating show_table for new_cpu %u from last_cpu %u\n",
 256                         policy->cpu, policy->last_cpu);
 257         per_cpu(cpufreq_show_table, policy->cpu) = per_cpu(cpufreq_show_table,
 258                         policy->last_cpu);
 259         per_cpu(cpufreq_show_table, policy->last_cpu) = NULL;
 260 }
 261
 262 struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu)
 263 {
 264         return per_cpu(cpufreq_show_table, cpu);
 265 }
 266 EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table);
 267
 268 MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
 269 MODULE_DESCRIPTION("CPUfreq frequency table helpers");
 270 MODULE_LICENSE("GPL");