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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14#include <linux/kernel.h>
  15#include <linux/module.h>
  16#include <linux/init.h>
  17#include <linux/cpufreq.h>
  18
  19/*********************************************************************
  20 *                     FREQUENCY TABLE HELPERS                       *
  21 *********************************************************************/
  22
  23int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
  24                                    struct cpufreq_frequency_table *table)
  25{
  26        unsigned int min_freq = ~0;
  27        unsigned int max_freq = 0;
  28        unsigned int i;
  29
  30        for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
  31                unsigned int freq = table[i].frequency;
  32                if (freq == CPUFREQ_ENTRY_INVALID) {
  33                        pr_debug("table entry %u is invalid, skipping\n", i);
  34
  35                        continue;
  36                }
  37                pr_debug("table entry %u: %u kHz, %u index\n",
  38                                        i, freq, table[i].index);
  39                if (freq < min_freq)
  40                        min_freq = freq;
  41                if (freq > max_freq)
  42                        max_freq = freq;
  43        }
  44
  45        policy->min = policy->cpuinfo.min_freq = min_freq;
  46        policy->max = policy->cpuinfo.max_freq = max_freq;
  47
  48        if (policy->min == ~0)
  49                return -EINVAL;
  50        else
  51                return 0;
  52}
  53EXPORT_SYMBOL_GPL(cpufreq_frequency_table_cpuinfo);
  54
  55
  56int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
  57                                   struct cpufreq_frequency_table *table)
  58{
  59        unsigned int next_larger = ~0;
  60        unsigned int i;
  61        unsigned int count = 0;
  62
  63        pr_debug("request for verification of policy (%u - %u kHz) for cpu %u\n",
  64                                        policy->min, policy->max, policy->cpu);
  65
  66        cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
  67                                     policy->cpuinfo.max_freq);
  68
  69        for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
  70                unsigned int freq = table[i].frequency;
  71                if (freq == CPUFREQ_ENTRY_INVALID)
  72                        continue;
  73                if ((freq >= policy->min) && (freq <= policy->max))
  74                        count++;
  75                else if ((next_larger > freq) && (freq > policy->max))
  76                        next_larger = freq;
  77        }
  78
  79        if (!count)
  80                policy->max = next_larger;
  81
  82        cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
  83                                     policy->cpuinfo.max_freq);
  84
  85        pr_debug("verification lead to (%u - %u kHz) for cpu %u\n",
  86                                policy->min, policy->max, policy->cpu);
  87
  88        return 0;
  89}
  90EXPORT_SYMBOL_GPL(cpufreq_frequency_table_verify);
  91
  92
  93int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
  94                                   struct cpufreq_frequency_table *table,
  95                                   unsigned int target_freq,
  96                                   unsigned int relation,
  97                                   unsigned int *index)
  98{
  99        struct cpufreq_frequency_table optimal = {
 100                .index = ~0,
 101                .frequency = 0,
 102        };
 103        struct cpufreq_frequency_table suboptimal = {
 104                .index = ~0,
 105                .frequency = 0,
 106        };
 107        unsigned int i;
 108
 109        pr_debug("request for target %u kHz (relation: %u) for cpu %u\n",
 110                                        target_freq, relation, policy->cpu);
 111
 112        switch (relation) {
 113        case CPUFREQ_RELATION_H:
 114                suboptimal.frequency = ~0;
 115                break;
 116        case CPUFREQ_RELATION_L:
 117                optimal.frequency = ~0;
 118                break;
 119        }
 120
 121        for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
 122                unsigned int freq = table[i].frequency;
 123                if (freq == CPUFREQ_ENTRY_INVALID)
 124                        continue;
 125                if ((freq < policy->min) || (freq > policy->max))
 126                        continue;
 127                switch (relation) {
 128                case CPUFREQ_RELATION_H:
 129                        if (freq <= target_freq) {
 130                                if (freq >= optimal.frequency) {
 131                                        optimal.frequency = freq;
 132                                        optimal.index = i;
 133                                }
 134                        } else {
 135                                if (freq <= suboptimal.frequency) {
 136                                        suboptimal.frequency = freq;
 137                                        suboptimal.index = i;
 138                                }
 139                        }
 140                        break;
 141                case CPUFREQ_RELATION_L:
 142                        if (freq >= target_freq) {
 143                                if (freq <= optimal.frequency) {
 144                                        optimal.frequency = freq;
 145                                        optimal.index = i;
 146                                }
 147                        } else {
 148                                if (freq >= suboptimal.frequency) {
 149                                        suboptimal.frequency = freq;
 150                                        suboptimal.index = i;
 151                                }
 152                        }
 153                        break;
 154                }
 155        }
 156        if (optimal.index > i) {
 157                if (suboptimal.index > i)
 158                        return -EINVAL;
 159                *index = suboptimal.index;
 160        } else
 161                *index = optimal.index;
 162
 163        pr_debug("target is %u (%u kHz, %u)\n", *index, table[*index].frequency,
 164                table[*index].index);
 165
 166        return 0;
 167}
 168EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);
 169
 170static DEFINE_PER_CPU(struct cpufreq_frequency_table *, cpufreq_show_table);
 171/**
 172 * show_available_freqs - show available frequencies for the specified CPU
 173 */
 174static ssize_t show_available_freqs(struct cpufreq_policy *policy, char *buf)
 175{
 176        unsigned int i = 0;
 177        unsigned int cpu = policy->cpu;
 178        ssize_t count = 0;
 179        struct cpufreq_frequency_table *table;
 180
 181        if (!per_cpu(cpufreq_show_table, cpu))
 182                return -ENODEV;
 183
 184        table = per_cpu(cpufreq_show_table, cpu);
 185
 186        for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
 187                if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
 188                        continue;
 189                count += sprintf(&buf[count], "%d ", table[i].frequency);
 190        }
 191        count += sprintf(&buf[count], "\n");
 192
 193        return count;
 194
 195}
 196
 197struct freq_attr cpufreq_freq_attr_scaling_available_freqs = {
 198        .attr = { .name = "scaling_available_frequencies",
 199                  .mode = 0444,
 200                },
 201        .show = show_available_freqs,
 202};
 203EXPORT_SYMBOL_GPL(cpufreq_freq_attr_scaling_available_freqs);
 204
 205/*
 206 * if you use these, you must assure that the frequency table is valid
 207 * all the time between get_attr and put_attr!
 208 */
 209void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
 210                                      unsigned int cpu)
 211{
 212        pr_debug("setting show_table for cpu %u to %p\n", cpu, table);
 213        per_cpu(cpufreq_show_table, cpu) = table;
 214}
 215EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_attr);
 216
 217void cpufreq_frequency_table_put_attr(unsigned int cpu)
 218{
 219        pr_debug("clearing show_table for cpu %u\n", cpu);
 220        per_cpu(cpufreq_show_table, cpu) = NULL;
 221}
 222EXPORT_SYMBOL_GPL(cpufreq_frequency_table_put_attr);
 223
 224void cpufreq_frequency_table_update_policy_cpu(struct cpufreq_policy *policy)
 225{
 226        pr_debug("Updating show_table for new_cpu %u from last_cpu %u\n",
 227                        policy->cpu, policy->last_cpu);
 228        per_cpu(cpufreq_show_table, policy->cpu) = per_cpu(cpufreq_show_table,
 229                        policy->last_cpu);
 230        per_cpu(cpufreq_show_table, policy->last_cpu) = NULL;
 231}
 232
 233struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu)
 234{
 235        return per_cpu(cpufreq_show_table, cpu);
 236}
 237EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table);
 238
 239MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
 240MODULE_DESCRIPTION("CPUfreq frequency table helpers");
 241MODULE_LICENSE("GPL");
 242
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