freq_table.c

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/*
 * linux/drivers/cpufreq/freq_table.c
 *
 * Copyright (C) 2002 - 2003 Dominik Brodowski
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>

/*********************************************************************
 *                     FREQUENCY TABLE HELPERS                       *
 *********************************************************************/

int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
                    struct cpufreq_frequency_table *table)
{
    unsigned int min_freq = ~0;
    unsigned int max_freq = 0;
    unsigned int i;

    for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
        unsigned int freq = table[i].frequency;
        if (freq == CPUFREQ_ENTRY_INVALID) {
            pr_debug("table entry %u is invalid, skipping\n", i);

            continue;
        }
        pr_debug("table entry %u: %u kHz, %u index\n",
                    i, freq, table[i].index);
        if (freq < min_freq)
            min_freq = freq;
        if (freq > max_freq)
            max_freq = freq;
    }

    policy->min = policy->cpuinfo.min_freq = min_freq;
    policy->max = policy->cpuinfo.max_freq = max_freq;

    if (policy->min == ~0)
        return -EINVAL;
    else
        return 0;
}
EXPORT_SYMBOL_GPL(cpufreq_frequency_table_cpuinfo);


int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
                   struct cpufreq_frequency_table *table)
{
    unsigned int next_larger = ~0;
    unsigned int i;
    unsigned int count = 0;

    pr_debug("request for verification of policy (%u - %u kHz) for cpu %u\n",
                    policy->min, policy->max, policy->cpu);

    if (!cpu_online(policy->cpu))
        return -EINVAL;

    cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
                     policy->cpuinfo.max_freq);

    for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
        unsigned int freq = table[i].frequency;
        if (freq == CPUFREQ_ENTRY_INVALID)
            continue;
        if ((freq >= policy->min) && (freq <= policy->max))
            count++;
        else if ((next_larger > freq) && (freq > policy->max))
            next_larger = freq;
    }

    if (!count)
        policy->max = next_larger;

    cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
                     policy->cpuinfo.max_freq);

    pr_debug("verification lead to (%u - %u kHz) for cpu %u\n",
                policy->min, policy->max, policy->cpu);

    return 0;
}
EXPORT_SYMBOL_GPL(cpufreq_frequency_table_verify);


int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
                   struct cpufreq_frequency_table *table,
                   unsigned int target_freq,
                   unsigned int relation,
                   unsigned int *index)
{
    struct cpufreq_frequency_table optimal = {
        .index = ~0,
        .frequency = 0,
    };
    struct cpufreq_frequency_table suboptimal = {
        .index = ~0,
        .frequency = 0,
    };
    unsigned int i;

    pr_debug("request for target %u kHz (relation: %u) for cpu %u\n",
                    target_freq, relation, policy->cpu);

    switch (relation) {
    case CPUFREQ_RELATION_H:
        suboptimal.frequency = ~0;
        break;
    case CPUFREQ_RELATION_L:
        optimal.frequency = ~0;
        break;
    }

    if (!cpu_online(policy->cpu))
        return -EINVAL;

    for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
        unsigned int freq = table[i].frequency;
        if (freq == CPUFREQ_ENTRY_INVALID)
            continue;
        if ((freq < policy->min) || (freq > policy->max))
            continue;
        switch (relation) {
        case CPUFREQ_RELATION_H:
            if (freq <= target_freq) {
                if (freq >= optimal.frequency) {
                    optimal.frequency = freq;
                    optimal.index = i;
                }
            } else {
                if (freq <= suboptimal.frequency) {
                    suboptimal.frequency = freq;
                    suboptimal.index = i;
                }
            }
            break;
        case CPUFREQ_RELATION_L:
            if (freq >= target_freq) {
                if (freq <= optimal.frequency) {
                    optimal.frequency = freq;
                    optimal.index = i;
                }
            } else {
                if (freq >= suboptimal.frequency) {
                    suboptimal.frequency = freq;
                    suboptimal.index = i;
                }
            }
            break;
        }
    }
    if (optimal.index > i) {
        if (suboptimal.index > i)
            return -EINVAL;
        *index = suboptimal.index;
    } else
        *index = optimal.index;

    pr_debug("target is %u (%u kHz, %u)\n", *index, table[*index].frequency,
        table[*index].index);

    return 0;
}
EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);

static DEFINE_PER_CPU(struct cpufreq_frequency_table *, cpufreq_show_table);
static ssize_t show_available_freqs(struct cpufreq_policy *policy, char *buf)
{
    unsigned int i = 0;
    unsigned int cpu = policy->cpu;
    ssize_t count = 0;
    struct cpufreq_frequency_table *table;

    if (!per_cpu(cpufreq_show_table, cpu))
        return -ENODEV;

    table = per_cpu(cpufreq_show_table, cpu);

    for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
        if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
            continue;
        count += sprintf(&buf[count], "%d ", table[i].frequency);
    }
    count += sprintf(&buf[count], "\n");

    return count;

}

struct freq_attr cpufreq_freq_attr_scaling_available_freqs = {
    .attr = { .name = "scaling_available_frequencies",
          .mode = 0444,
        },
    .show = show_available_freqs,
};
EXPORT_SYMBOL_GPL(cpufreq_freq_attr_scaling_available_freqs);

/*
 * if you use these, you must assure that the frequency table is valid
 * all the time between get_attr and put_attr!
 */
void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
                      unsigned int cpu)
{
    pr_debug("setting show_table for cpu %u to %p\n", cpu, table);
    per_cpu(cpufreq_show_table, cpu) = table;
}
EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_attr);

void cpufreq_frequency_table_put_attr(unsigned int cpu)
{
    pr_debug("clearing show_table for cpu %u\n", cpu);
    per_cpu(cpufreq_show_table, cpu) = NULL;
}
EXPORT_SYMBOL_GPL(cpufreq_frequency_table_put_attr);

struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu)
{
    return per_cpu(cpufreq_show_table, cpu);
}
EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table);

MODULE_AUTHOR("Dominik Brodowski <[email protected]>");
MODULE_DESCRIPTION("CPUfreq frequency table helpers");
MODULE_LICENSE("GPL");