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