drivers/cpufreq/freq_table.c

   1 /*
   2  * linux/drivers/cpufreq/freq_table.c
   3  *
   4  * Copyright (C) 2002 - 2003 Dominik Brodowski
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/module.h>
   9 #include <linux/init.h>
  10 #include <linux/cpufreq.h>
  11
  12 /*********************************************************************
  13  *                     FREQUENCY TABLE HELPERS                       *
  14  *********************************************************************/
  15
  16 int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
  17                                     struct cpufreq_frequency_table *table)
  18 {
  19         unsigned int min_freq = ~0;
  20         unsigned int max_freq = 0;
  21         unsigned int i = 0;
  22
  23         for (i=0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
  24                 unsigned int freq = table[i].frequency;
  25                 if (freq == CPUFREQ_ENTRY_INVALID)
  26                         continue;
  27                 if (freq < min_freq)
  28                         min_freq = freq;
  29                 if (freq > max_freq)
  30                         max_freq = freq;
  31         }
  32
  33         policy->min = policy->cpuinfo.min_freq = min_freq;
  34         policy->max = policy->cpuinfo.max_freq = max_freq;
  35
  36         if (policy->min == ~0)
  37                 return -EINVAL;
  38         else
  39                 return 0;
  40 }
  41 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_cpuinfo);
  42
  43
  44 int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
  45                                    struct cpufreq_frequency_table *table)
  46 {
  47         unsigned int next_larger = ~0;
  48         unsigned int i = 0;
  49         unsigned int count = 0;
  50
  51         if (!cpu_online(policy->cpu))
  52                 return -EINVAL;
  53
  54         cpufreq_verify_within_limits(policy,
  55                                      policy->cpuinfo.min_freq,
  56                                      policy->cpuinfo.max_freq);
  57
  58         for (i=0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
  59                 unsigned int freq = table[i].frequency;
  60                 if (freq == CPUFREQ_ENTRY_INVALID)
  61                         continue;
  62                 if ((freq >= policy->min) && (freq <= policy->max))
  63                         count++;
  64                 else if ((next_larger > freq) && (freq > policy->max))
  65                         next_larger = freq;
  66         }
  67
  68         if (!count)
  69                 policy->max = next_larger;
  70
  71         cpufreq_verify_within_limits(policy,
  72                                      policy->cpuinfo.min_freq,
  73                                      policy->cpuinfo.max_freq);
  74
  75         return 0;
  76 }
  77 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_verify);
  78
  79
  80 int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
  81                                    struct cpufreq_frequency_table *table,
  82                                    unsigned int target_freq,
  83                                    unsigned int relation,
  84                                    unsigned int *index)
  85 {
  86         struct cpufreq_frequency_table optimal = { .index = ~0, };
  87         struct cpufreq_frequency_table suboptimal = { .index = ~0, };
  88         unsigned int i;
  89
  90         switch (relation) {
  91         case CPUFREQ_RELATION_H:
  92                 optimal.frequency = 0;
  93                 suboptimal.frequency = ~0;
  94                 break;
  95         case CPUFREQ_RELATION_L:
  96                 optimal.frequency = ~0;
  97                 suboptimal.frequency = 0;
  98                 break;
  99         }
 100
 101         if (!cpu_online(policy->cpu))
 102                 return -EINVAL;
 103
 104         for (i=0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
 105                 unsigned int freq = table[i].frequency;
 106                 if (freq == CPUFREQ_ENTRY_INVALID)
 107                         continue;
 108                 if ((freq < policy->min) || (freq > policy->max))
 109                         continue;
 110                 switch(relation) {
 111                 case CPUFREQ_RELATION_H:
 112                         if (freq <= target_freq) {
 113                                 if (freq >= optimal.frequency) {
 114                                         optimal.frequency = freq;
 115                                         optimal.index = i;
 116                                 }
 117                         } else {
 118                                 if (freq <= suboptimal.frequency) {
 119                                         suboptimal.frequency = freq;
 120                                         suboptimal.index = i;
 121                                 }
 122                         }
 123                         break;
 124                 case CPUFREQ_RELATION_L:
 125                         if (freq >= target_freq) {
 126                                 if (freq <= optimal.frequency) {
 127                                         optimal.frequency = freq;
 128                                         optimal.index = i;
 129                                 }
 130                         } else {
 131                                 if (freq >= suboptimal.frequency) {
 132                                         suboptimal.frequency = freq;
 133                                         suboptimal.index = i;
 134                                 }
 135                         }
 136                         break;
 137                 }
 138         }
 139         if (optimal.index > i) {
 140                 if (suboptimal.index > i)
 141                         return -EINVAL;
 142                 *index = suboptimal.index;
 143         } else
 144                 *index = optimal.index;
 145
 146         return 0;
 147 }
 148 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);
 149
 150 static struct cpufreq_frequency_table *show_table[NR_CPUS];
 151 /**
 152  * show_scaling_governor - show the current policy for the specified CPU
 153  */
 154 static ssize_t show_available_freqs (struct cpufreq_policy *policy, char *buf)
 155 {
 156         unsigned int i = 0;
 157         unsigned int cpu = policy->cpu;
 158         ssize_t count = 0;
 159         struct cpufreq_frequency_table *table;
 160
 161         if (!show_table[cpu])
 162                 return -ENODEV;
 163
 164         table = show_table[cpu];
 165
 166         for (i=0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
 167                 if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
 168                         continue;
 169                 count += sprintf(&buf[count], "%d ", table[i].frequency);
 170         }
 171         count += sprintf(&buf[count], "\n");
 172
 173         return count;
 174
 175 }
 176
 177 struct freq_attr cpufreq_freq_attr_scaling_available_freqs = {
 178         .attr = { .name = "scaling_available_frequencies", .mode = 0444 },
 179         .show = show_available_freqs,
 180 };
 181 EXPORT_SYMBOL_GPL(cpufreq_freq_attr_scaling_available_freqs);
 182
 183 /*
 184  * if you use these, you must assure that the frequency table is valid
 185  * all the time between get_attr and put_attr!
 186  */
 187 void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
 188                                       unsigned int cpu)
 189 {
 190         show_table[cpu] = table;
 191 }
 192 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_attr);
 193
 194 void cpufreq_frequency_table_put_attr(unsigned int cpu)
 195 {
 196         show_table[cpu] = NULL;
 197 }
 198 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_put_attr);
 199
 200
 201 MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>");
 202 MODULE_DESCRIPTION ("CPUfreq frequency table helpers");
 203 MODULE_LICENSE ("GPL");