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