linux/drivers/cpufreq/freq_table.c
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   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
  21int 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}
  51EXPORT_SYMBOL_GPL(cpufreq_frequency_table_cpuinfo);
  52
  53
  54int 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}
  91EXPORT_SYMBOL_GPL(cpufreq_frequency_table_verify);
  92
  93
  94int 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}
 172EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);
 173
 174static DEFINE_PER_CPU(struct cpufreq_frequency_table *, cpufreq_show_table);
 175/**
 176 * show_available_freqs - show available frequencies for the specified CPU
 177 */
 178static 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
 201struct freq_attr cpufreq_freq_attr_scaling_available_freqs = {
 202        .attr = { .name = "scaling_available_frequencies",
 203                  .mode = 0444,
 204                },
 205        .show = show_available_freqs,
 206};
 207EXPORT_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 */
 213void 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}
 219EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_attr);
 220
 221void 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}
 226EXPORT_SYMBOL_GPL(cpufreq_frequency_table_put_attr);
 227
 228struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu)
 229{
 230        return per_cpu(cpufreq_show_table, cpu);
 231}
 232EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table);
 233
 234MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
 235MODULE_DESCRIPTION("CPUfreq frequency table helpers");
 236MODULE_LICENSE("GPL");
 237
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