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freq_table.c

/*
 * linux/drivers/cpufreq/freq_table.c
 *
 * Copyright (C) 2002 - 2003 Dominik Brodowski
 */

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

#define dprintk(msg...) \
      cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, "freq-table", msg)

/*********************************************************************
 *                     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) {
                  dprintk("table entry %u is invalid, skipping\n", i);

                  continue;
            }
            dprintk("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;

      dprintk("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);

      dprintk("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;

      dprintk("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;

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

      return 0;
}
EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);

static struct cpufreq_frequency_table *show_table[NR_CPUS];
/**
 * show_scaling_governor - show the current policy for the specified CPU
 */
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 (!show_table[cpu])
            return -ENODEV;

      table = 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)
{
      dprintk("setting show_table for cpu %u to %p\n", cpu, table);
      show_table[cpu] = table;
}
EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_attr);

void cpufreq_frequency_table_put_attr(unsigned int cpu)
{
      dprintk("clearing show_table for cpu %u\n", cpu);
      show_table[cpu] = NULL;
}
EXPORT_SYMBOL_GPL(cpufreq_frequency_table_put_attr);

struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu)
{
      return show_table[cpu];
}
EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table);

MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>");
MODULE_DESCRIPTION ("CPUfreq frequency table helpers");
MODULE_LICENSE ("GPL");

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