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 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, "freq-table", msg)
  13
  14 /*********************************************************************
  15  *                     FREQUENCY TABLE HELPERS                       *
  16  *********************************************************************/
  17
  18 int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
  19                                     struct cpufreq_frequency_table *table)
  20 {
  21         unsigned int min_freq = ~0;
  22         unsigned int max_freq = 0;
  23         unsigned int i;
  24
  25         for (i=0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
  26                 unsigned int freq = table[i].frequency;
  27                 if (freq == CPUFREQ_ENTRY_INVALID) {
  28                         dprintk("table entry %u is invalid, skipping\n", i);
  29
  30                         continue;
  31                 }
  32                 dprintk("table entry %u: %u kHz, %u index\n", i, freq, table[i].index);
  33                 if (freq < min_freq)
  34                         min_freq = freq;
  35                 if (freq > max_freq)
  36                         max_freq = freq;
  37         }
  38
  39         policy->min = policy->cpuinfo.min_freq = min_freq;
  40         policy->max = policy->cpuinfo.max_freq = max_freq;
  41
  42         if (policy->min == ~0)
  43                 return -EINVAL;
  44         else
  45                 return 0;
  46 }
  47 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_cpuinfo);
  48
  49
  50 int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
  51                                    struct cpufreq_frequency_table *table)
  52 {
  53         unsigned int next_larger = ~0;
  54         unsigned int i;
  55         unsigned int count = 0;
  56
  57         dprintk("request for verification of policy (%u - %u kHz) for cpu %u\n", policy->min, policy->max, policy->cpu);
  58
  59         if (!cpu_online(policy->cpu))
  60                 return -EINVAL;
  61
  62         cpufreq_verify_within_limits(policy,
  63                                      policy->cpuinfo.min_freq, policy->cpuinfo.max_freq);
  64
  65         for (i=0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
  66                 unsigned int freq = table[i].frequency;
  67                 if (freq == CPUFREQ_ENTRY_INVALID)
  68                         continue;
  69                 if ((freq >= policy->min) && (freq <= policy->max))
  70                         count++;
  71                 else if ((next_larger > freq) && (freq > policy->max))
  72                         next_larger = freq;
  73         }
  74
  75         if (!count)
  76                 policy->max = next_larger;
  77
  78         cpufreq_verify_within_limits(policy,
  79                                      policy->cpuinfo.min_freq, policy->cpuinfo.max_freq);
  80
  81         dprintk("verification lead to (%u - %u kHz) for cpu %u\n", policy->min, policy->max, policy->cpu);
  82
  83         return 0;
  84 }
  85 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_verify);
  86
  87
  88 int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
  89                                    struct cpufreq_frequency_table *table,
  90                                    unsigned int target_freq,
  91                                    unsigned int relation,
  92                                    unsigned int *index)
  93 {
  94         struct cpufreq_frequency_table optimal = {
  95                 .index = ~0,
  96                 .frequency = 0,
  97         };
  98         struct cpufreq_frequency_table suboptimal = {
  99                 .index = ~0,
 100                 .frequency = 0,
 101         };
 102         unsigned int i;
 103
 104         dprintk("request for target %u kHz (relation: %u) for cpu %u\n", target_freq, relation, policy->cpu);
 105
 106         switch (relation) {
 107         case CPUFREQ_RELATION_H:
 108                 suboptimal.frequency = ~0;
 109                 break;
 110         case CPUFREQ_RELATION_L:
 111                 optimal.frequency = ~0;
 112                 break;
 113         }
 114
 115         if (!cpu_online(policy->cpu))
 116                 return -EINVAL;
 117
 118         for (i=0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
 119                 unsigned int freq = table[i].frequency;
 120                 if (freq == CPUFREQ_ENTRY_INVALID)
 121                         continue;
 122                 if ((freq < policy->min) || (freq > policy->max))
 123                         continue;
 124                 switch(relation) {
 125                 case CPUFREQ_RELATION_H:
 126                         if (freq <= target_freq) {
 127                                 if (freq >= optimal.frequency) {
 128                                         optimal.frequency = freq;
 129                                         optimal.index = i;
 130                                 }
 131                         } else {
 132                                 if (freq <= suboptimal.frequency) {
 133                                         suboptimal.frequency = freq;
 134                                         suboptimal.index = i;
 135                                 }
 136                         }
 137                         break;
 138                 case CPUFREQ_RELATION_L:
 139                         if (freq >= target_freq) {
 140                                 if (freq <= optimal.frequency) {
 141                                         optimal.frequency = freq;
 142                                         optimal.index = i;
 143                                 }
 144                         } else {
 145                                 if (freq >= suboptimal.frequency) {
 146                                         suboptimal.frequency = freq;
 147                                         suboptimal.index = i;
 148                                 }
 149                         }
 150                         break;
 151                 }
 152         }
 153         if (optimal.index > i) {
 154                 if (suboptimal.index > i)
 155                         return -EINVAL;
 156                 *index = suboptimal.index;
 157         } else
 158                 *index = optimal.index;
 159
 160         dprintk("target is %u (%u kHz, %u)\n", *index, table[*index].frequency,
 161                 table[*index].index);
 162
 163         return 0;
 164 }
 165 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);
 166
 167 static struct cpufreq_frequency_table *show_table[NR_CPUS];
 168 /**
 169  * show_scaling_governor - show the current policy for the specified CPU
 170  */
 171 static ssize_t show_available_freqs (struct cpufreq_policy *policy, char *buf)
 172 {
 173         unsigned int i = 0;
 174         unsigned int cpu = policy->cpu;
 175         ssize_t count = 0;
 176         struct cpufreq_frequency_table *table;
 177
 178         if (!show_table[cpu])
 179                 return -ENODEV;
 180
 181         table = show_table[cpu];
 182
 183         for (i=0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
 184                 if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
 185                         continue;
 186                 count += sprintf(&buf[count], "%d ", table[i].frequency);
 187         }
 188         count += sprintf(&buf[count], "\n");
 189
 190         return count;
 191
 192 }
 193
 194 struct freq_attr cpufreq_freq_attr_scaling_available_freqs = {
 195         .attr = { .name = "scaling_available_frequencies", .mode = 0444, .owner=THIS_MODULE },
 196         .show = show_available_freqs,
 197 };
 198 EXPORT_SYMBOL_GPL(cpufreq_freq_attr_scaling_available_freqs);
 199
 200 /*
 201  * if you use these, you must assure that the frequency table is valid
 202  * all the time between get_attr and put_attr!
 203  */
 204 void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
 205                                       unsigned int cpu)
 206 {
 207         dprintk("setting show_table for cpu %u to %p\n", cpu, table);
 208         show_table[cpu] = table;
 209 }
 210 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_attr);
 211
 212 void cpufreq_frequency_table_put_attr(unsigned int cpu)
 213 {
 214         dprintk("clearing show_table for cpu %u\n", cpu);
 215         show_table[cpu] = NULL;
 216 }
 217 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_put_attr);
 218
 219 struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu)
 220 {
 221         return show_table[cpu];
 222 }
 223 EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table);
 224
 225 MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>");
 226 MODULE_DESCRIPTION ("CPUfreq frequency table helpers");
 227 MODULE_LICENSE ("GPL");