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