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