release/src-rt-6.x.4708/linux/linux-2.6.36/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 #define dprintk(msg...) \
  18         cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, "freq-table", msg)
  19
  20 /*********************************************************************
  21  *                     FREQUENCY TABLE HELPERS                       *
  22  *********************************************************************/
  23
  24 int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
  25                                     struct cpufreq_frequency_table *table)
  26 {
  27         unsigned int min_freq = ~0;
  28         unsigned int max_freq = 0;
  29         unsigned int i;
  30
  31         for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
  32                 unsigned int freq = table[i].frequency;
  33                 if (freq == CPUFREQ_ENTRY_INVALID) {
  34                         dprintk("table entry %u is invalid, skipping\n", i);
  35
  36                         continue;
  37                 }
  38                 dprintk("table entry %u: %u kHz, %u index\n",
  39                                         i, freq, table[i].index);
  40                 if (freq < min_freq)
  41                         min_freq = freq;
  42                 if (freq > max_freq)
  43                         max_freq = freq;
  44         }
  45
  46         policy->min = policy->cpuinfo.min_freq = min_freq;
  47         policy->max = policy->cpuinfo.max_freq = max_freq;
  48
  49         if (policy->min == ~0)
  50                 return -EINVAL;
  51         else
  52                 return 0;
  53 }
  54 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_cpuinfo);
  55
  56
  57 int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
  58                                    struct cpufreq_frequency_table *table)
  59 {
  60         unsigned int next_larger = ~0;
  61         unsigned int i;
  62         unsigned int count = 0;
  63
  64         dprintk("request for verification of policy (%u - %u kHz) for cpu %u\n",
  65                                         policy->min, policy->max, policy->cpu);
  66
  67         if (!cpu_online(policy->cpu))
  68                 return -EINVAL;
  69
  70         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
  71                                      policy->cpuinfo.max_freq);
  72
  73         for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
  74                 unsigned int freq = table[i].frequency;
  75                 if (freq == CPUFREQ_ENTRY_INVALID)
  76                         continue;
  77                 if ((freq >= policy->min) && (freq <= policy->max))
  78                         count++;
  79                 else if ((next_larger > freq) && (freq > policy->max))
  80                         next_larger = freq;
  81         }
  82
  83         if (!count)
  84                 policy->max = next_larger;
  85
  86         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
  87                                      policy->cpuinfo.max_freq);
  88
  89         dprintk("verification lead to (%u - %u kHz) for cpu %u\n",
  90                                 policy->min, policy->max, policy->cpu);
  91
  92         return 0;
  93 }
  94 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_verify);
  95
  96
  97 int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
  98                                    struct cpufreq_frequency_table *table,
  99                                    unsigned int target_freq,
 100                                    unsigned int relation,
 101                                    unsigned int *index)
 102 {
 103         struct cpufreq_frequency_table optimal = {
 104                 .index = ~0,
 105                 .frequency = 0,
 106         };
 107         struct cpufreq_frequency_table suboptimal = {
 108                 .index = ~0,
 109                 .frequency = 0,
 110         };
 111         unsigned int i;
 112
 113         dprintk("request for target %u kHz (relation: %u) for cpu %u\n",
 114                                         target_freq, relation, policy->cpu);
 115
 116         switch (relation) {
 117         case CPUFREQ_RELATION_H:
 118                 suboptimal.frequency = ~0;
 119                 break;
 120         case CPUFREQ_RELATION_L:
 121                 optimal.frequency = ~0;
 122                 break;
 123         }
 124
 125         if (!cpu_online(policy->cpu))
 126                 return -EINVAL;
 127
 128         for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
 129                 unsigned int freq = table[i].frequency;
 130                 if (freq == CPUFREQ_ENTRY_INVALID)
 131                         continue;
 132                 if ((freq < policy->min) || (freq > policy->max))
 133                         continue;
 134                 switch (relation) {
 135                 case CPUFREQ_RELATION_H:
 136                         if (freq <= target_freq) {
 137                                 if (freq >= optimal.frequency) {
 138                                         optimal.frequency = freq;
 139                                         optimal.index = i;
 140                                 }
 141                         } else {
 142                                 if (freq <= suboptimal.frequency) {
 143                                         suboptimal.frequency = freq;
 144                                         suboptimal.index = i;
 145                                 }
 146                         }
 147                         break;
 148                 case CPUFREQ_RELATION_L:
 149                         if (freq >= target_freq) {
 150                                 if (freq <= optimal.frequency) {
 151                                         optimal.frequency = freq;
 152                                         optimal.index = i;
 153                                 }
 154                         } else {
 155                                 if (freq >= suboptimal.frequency) {
 156                                         suboptimal.frequency = freq;
 157                                         suboptimal.index = i;
 158                                 }
 159                         }
 160                         break;
 161                 }
 162         }
 163         if (optimal.index > i) {
 164                 if (suboptimal.index > i)
 165                         return -EINVAL;
 166                 *index = suboptimal.index;
 167         } else
 168                 *index = optimal.index;
 169
 170         dprintk("target is %u (%u kHz, %u)\n", *index, table[*index].frequency,
 171                 table[*index].index);
 172
 173         return 0;
 174 }
 175 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);
 176
 177 static DEFINE_PER_CPU(struct cpufreq_frequency_table *, cpufreq_show_table);
 178 /**
 179  * show_available_freqs - show available frequencies for the specified CPU
 180  */
 181 static ssize_t show_available_freqs(struct cpufreq_policy *policy, char *buf)
 182 {
 183         unsigned int i = 0;
 184         unsigned int cpu = policy->cpu;
 185         ssize_t count = 0;
 186         struct cpufreq_frequency_table *table;
 187
 188         if (!per_cpu(cpufreq_show_table, cpu))
 189                 return -ENODEV;
 190
 191         table = per_cpu(cpufreq_show_table, cpu);
 192
 193         for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
 194                 if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
 195                         continue;
 196                 count += sprintf(&buf[count], "%d ", table[i].frequency);
 197         }
 198         count += sprintf(&buf[count], "\n");
 199
 200         return count;
 201
 202 }
 203
 204 struct freq_attr cpufreq_freq_attr_scaling_available_freqs = {
 205         .attr = { .name = "scaling_available_frequencies",
 206                   .mode = 0444,
 207                 },
 208         .show = show_available_freqs,
 209 };
 210 EXPORT_SYMBOL_GPL(cpufreq_freq_attr_scaling_available_freqs);
 211
 212 /*
 213  * if you use these, you must assure that the frequency table is valid
 214  * all the time between get_attr and put_attr!
 215  */
 216 void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
 217                                       unsigned int cpu)
 218 {
 219         dprintk("setting show_table for cpu %u to %p\n", cpu, table);
 220         per_cpu(cpufreq_show_table, cpu) = table;
 221 }
 222 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_attr);
 223
 224 void cpufreq_frequency_table_put_attr(unsigned int cpu)
 225 {
 226         dprintk("clearing show_table for cpu %u\n", cpu);
 227         per_cpu(cpufreq_show_table, cpu) = NULL;
 228 }
 229 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_put_attr);
 230
 231 struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu)
 232 {
 233         return per_cpu(cpufreq_show_table, cpu);
 234 }
 235 EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table);
 236
 237 MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
 238 MODULE_DESCRIPTION("CPUfreq frequency table helpers");
 239 MODULE_LICENSE("GPL");