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/*

 *  drivers/cpufreq/cpufreq_stats.c

 *

 *  Copyright (C) 2003-2004 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.

 *            (C) 2004 Zou Nan hai <nanhai.zou@intel.com>.

 *

 * 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/sysdev.h>

#include <linux/cpu.h>

#include <linux/sysfs.h>

#include <linux/cpufreq.h>

#include <linux/jiffies.h>

#include <linux/percpu.h>

#include <linux/kobject.h>

#include <linux/spinlock.h>

#include <linux/notifier.h>

#include <asm/cputime.h>

static spinlock_t cpufreq_stats_lock;

#define CPUFREQ_STATDEVICE_ATTR(_name,_mode,_show) \

static struct freq_attr _attr_##_name = {\

        .attr = {.name = __stringify(_name), .mode = _mode, }, \

        .show = _show,\

};

struct cpufreq_stats {

        unsigned int cpu;

        unsigned int total_trans;

        unsigned long long  last_time;

        unsigned int max_state;

        unsigned int state_num;

        unsigned int last_index;

        cputime64_t *time_in_state;

        unsigned int *freq_table;

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS

        unsigned int *trans_table;

#endif

};

static struct cpufreq_stats *cpufreq_stats_table[NR_CPUS];

struct cpufreq_stats_attribute {

        struct attribute attr;

        ssize_t(*show) (struct cpufreq_stats *, char *);

};

static int

cpufreq_stats_update (unsigned int cpu)

{

        struct cpufreq_stats *stat;

        unsigned long long cur_time;

        cur_time = get_jiffies_64();

        spin_lock(&cpufreq_stats_lock);

        stat = cpufreq_stats_table[cpu];

        if (stat->time_in_state)

                stat->time_in_state[stat->last_index] =

                        cputime64_add(stat->time_in_state[stat->last_index],

                                      cputime_sub(cur_time, stat->last_time));

        stat->last_time = cur_time;

        spin_unlock(&cpufreq_stats_lock);

        return 0;

}

static ssize_t

show_total_trans(struct cpufreq_policy *policy, char *buf)

{

        struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];

        if (!stat)

                return 0;

        return sprintf(buf, "%d\n",

                        cpufreq_stats_table[stat->cpu]->total_trans);

}

static ssize_t

show_time_in_state(struct cpufreq_policy *policy, char *buf)

{

        ssize_t len = 0;

        int i;

        struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];

        if (!stat)

                return 0;

        cpufreq_stats_update(stat->cpu);

        for (i = 0; i < stat->state_num; i++) {

                len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],

                        (unsigned long long)cputime64_to_clock_t(stat->time_in_state[i]));

        }

        return len;

}

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS

static ssize_t

show_trans_table(struct cpufreq_policy *policy, char *buf)

{

        ssize_t len = 0;

        int i, j;

        struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];

        if (!stat)

                return 0;

        cpufreq_stats_update(stat->cpu);

        len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");

        len += snprintf(buf + len, PAGE_SIZE - len, "         : ");

        for (i = 0; i < stat->state_num; i++) {

                if (len >= PAGE_SIZE)

                        break;

                len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",

                                stat->freq_table[i]);

        }

        if (len >= PAGE_SIZE)

                return len;

        len += snprintf(buf + len, PAGE_SIZE - len, "\n");

        for (i = 0; i < stat->state_num; i++) {

                if (len >= PAGE_SIZE)

                        break;

                len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",

                                stat->freq_table[i]);

                for (j = 0; j < stat->state_num; j++)   {

                        if (len >= PAGE_SIZE)

                                break;

                        len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",

                                        stat->trans_table[i*stat->max_state+j]);

                }

                len += snprintf(buf + len, PAGE_SIZE - len, "\n");

        }

        return len;

}

CPUFREQ_STATDEVICE_ATTR(trans_table,0444,show_trans_table);

#endif

CPUFREQ_STATDEVICE_ATTR(total_trans,0444,show_total_trans);

CPUFREQ_STATDEVICE_ATTR(time_in_state,0444,show_time_in_state);

static struct attribute *default_attrs[] = {

        &_attr_total_trans.attr,

        &_attr_time_in_state.attr,

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS

        &_attr_trans_table.attr,

#endif

        NULL

};

static struct attribute_group stats_attr_group = {

        .attrs = default_attrs,

        .name = "stats"

};

static int

freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)

{

        int index;

        for (index = 0; index < stat->max_state; index++)

                if (stat->freq_table[index] == freq)

                        return index;

        return -1;

}

static void cpufreq_stats_free_table(unsigned int cpu)

{

        struct cpufreq_stats *stat = cpufreq_stats_table[cpu];

        struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);

        if (policy && policy->cpu == cpu)

                sysfs_remove_group(&policy->kobj, &stats_attr_group);

        if (stat) {

                kfree(stat->time_in_state);

                kfree(stat);

        }

        cpufreq_stats_table[cpu] = NULL;

        if (policy)

                cpufreq_cpu_put(policy);

}

static int

cpufreq_stats_create_table (struct cpufreq_policy *policy,

                struct cpufreq_frequency_table *table)

{

        unsigned int i, j, count = 0, ret = 0;

        struct cpufreq_stats *stat;

        struct cpufreq_policy *data;

        unsigned int alloc_size;

        unsigned int cpu = policy->cpu;

        if (cpufreq_stats_table[cpu])

                return -EBUSY;

        if ((stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == NULL)

                return -ENOMEM;

        data = cpufreq_cpu_get(cpu);

        if (data == NULL) {

                ret = -EINVAL;

                goto error_get_fail;

        }

        if ((ret = sysfs_create_group(&data->kobj, &stats_attr_group)))

                goto error_out;

        stat->cpu = cpu;

        cpufreq_stats_table[cpu] = stat;

        for (i=0; table[i].frequency != CPUFREQ_TABLE_END; i++) {

                unsigned int freq = table[i].frequency;

                if (freq == CPUFREQ_ENTRY_INVALID)

                        continue;

                count++;

        }

        alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS

        alloc_size += count * count * sizeof(int);

#endif

        stat->max_state = count;

        stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);

        if (!stat->time_in_state) {

                ret = -ENOMEM;

                goto error_out;

        }

        stat->freq_table = (unsigned int *)(stat->time_in_state + count);

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS

        stat->trans_table = stat->freq_table + count;

#endif

        j = 0;

        for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {

                unsigned int freq = table[i].frequency;

                if (freq == CPUFREQ_ENTRY_INVALID)

                        continue;

                if (freq_table_get_index(stat, freq) == -1)

                        stat->freq_table[j++] = freq;

        }

        stat->state_num = j;

        spin_lock(&cpufreq_stats_lock);

        stat->last_time = get_jiffies_64();

        stat->last_index = freq_table_get_index(stat, policy->cur);

        spin_unlock(&cpufreq_stats_lock);

        cpufreq_cpu_put(data);

        return 0;

error_out:

        cpufreq_cpu_put(data);

error_get_fail:

        kfree(stat);

        cpufreq_stats_table[cpu] = NULL;

        return ret;

}

static int

cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val,

                void *data)

{

        int ret;

        struct cpufreq_policy *policy = data;

        struct cpufreq_frequency_table *table;

        unsigned int cpu = policy->cpu;

        if (val != CPUFREQ_NOTIFY)

                return 0;

        table = cpufreq_frequency_get_table(cpu);

        if (!table)

                return 0;

        if ((ret = cpufreq_stats_create_table(policy, table)))

                return ret;

        return 0;

}

static int

cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val,

                void *data)

{

        struct cpufreq_freqs *freq = data;

        struct cpufreq_stats *stat;

        int old_index, new_index;

        if (val != CPUFREQ_POSTCHANGE)

                return 0;

        stat = cpufreq_stats_table[freq->cpu];

        if (!stat)

                return 0;

        old_index = freq_table_get_index(stat, freq->old);

        new_index = freq_table_get_index(stat, freq->new);

        cpufreq_stats_update(freq->cpu);

        if (old_index == new_index)

                return 0;

        if (old_index == -1 || new_index == -1)

                return 0;

        spin_lock(&cpufreq_stats_lock);

        stat->last_index = new_index;

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS

        stat->trans_table[old_index * stat->max_state + new_index]++;

#endif

        stat->total_trans++;

        spin_unlock(&cpufreq_stats_lock);

        return 0;

}

static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,

                                               unsigned long action,

                                               void *hcpu)

{

        unsigned int cpu = (unsigned long)hcpu;

        switch (action) {

        case CPU_ONLINE:

        case CPU_ONLINE_FROZEN:

                cpufreq_update_policy(cpu);

                break;

        case CPU_DEAD:

        case CPU_DEAD_FROZEN:

                cpufreq_stats_free_table(cpu);

                break;

        }

        return NOTIFY_OK;

}

static struct notifier_block cpufreq_stat_cpu_notifier __cpuinitdata =

{

        .notifier_call = cpufreq_stat_cpu_callback,

};

static struct notifier_block notifier_policy_block = {

        .notifier_call = cpufreq_stat_notifier_policy

};

static struct notifier_block notifier_trans_block = {

        .notifier_call = cpufreq_stat_notifier_trans

};

static int

__init cpufreq_stats_init(void)

{

        int ret;

        unsigned int cpu;

        spin_lock_init(&cpufreq_stats_lock);

        if ((ret = cpufreq_register_notifier(&notifier_policy_block,

                                CPUFREQ_POLICY_NOTIFIER)))

                return ret;

        if ((ret = cpufreq_register_notifier(&notifier_trans_block,

                                CPUFREQ_TRANSITION_NOTIFIER))) {

                cpufreq_unregister_notifier(&notifier_policy_block,

                                CPUFREQ_POLICY_NOTIFIER);

                return ret;

        }

        register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);

        for_each_online_cpu(cpu) {

                cpufreq_update_policy(cpu);

        }

        return 0;

}

static void

__exit cpufreq_stats_exit(void)

{

        unsigned int cpu;

        cpufreq_unregister_notifier(&notifier_policy_block,

                        CPUFREQ_POLICY_NOTIFIER);

        cpufreq_unregister_notifier(&notifier_trans_block,

                        CPUFREQ_TRANSITION_NOTIFIER);

        unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);

        for_each_online_cpu(cpu) {

                cpufreq_stats_free_table(cpu);

        }

}

MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>");

MODULE_DESCRIPTION ("'cpufreq_stats' - A driver to export cpufreq stats "

                                "through sysfs filesystem");

MODULE_LICENSE ("GPL");

module_init(cpufreq_stats_init);

module_exit(cpufreq_stats_exit);