1 files changed, 334 insertions, 0 deletions

diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
new file mode 100644
index 000000000000..2084593937c6
--- /dev/null
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -0,0 +1,334 @@
+/*
+ *  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/config.h>
+#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>
+
+static spinlock_t cpufreq_stats_lock;
+
+#define CPUFREQ_STATDEVICE_ATTR(_name,_mode,_show) \
+static struct freq_attr _attr_##_name = {\
+        .attr = {.name = __stringify(_name), .owner = THIS_MODULE, \
+                .mode = _mode, }, \
+        .show = _show,\
+};
+
+static unsigned long
+delta_time(unsigned long old, unsigned long new)
+{
+        return (old > new) ? (old - new): (new + ~old + 1);
+}
+
+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;
+        unsigned long long *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;
+        spin_lock(&cpufreq_stats_lock);
+        stat = cpufreq_stats_table[cpu];
+        if (stat->time_in_state)
+                stat->time_in_state[stat->last_index] +=
+                        delta_time(stat->last_time, jiffies);
+        stat->last_time = jiffies;
+        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], 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);
+        for (i = 0; i < stat->state_num; i++) {
+                if (len >= PAGE_SIZE)
+                        break;
+                len += snprintf(buf + len, PAGE_SIZE - len, "%9u:\t",
+                                stat->freq_table[i]);
+
+                for (j = 0; j < stat->state_num; j++)   {
+                        if (len >= PAGE_SIZE)
+                                break;
+                        len += snprintf(buf + len, PAGE_SIZE - len, "%u\t",
+                                        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 = kmalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == NULL)
+                return -ENOMEM;
+        memset(stat, 0, sizeof (struct cpufreq_stats));
+
+        data = cpufreq_cpu_get(cpu);
+        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(long long);
+
+#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
+        alloc_size += count * count * sizeof(int);
+#endif
+        stat->max_state = count;
+        stat->time_in_state = kmalloc(alloc_size, GFP_KERNEL);
+        if (!stat->time_in_state) {
+                ret = -ENOMEM;
+                goto error_out;
+        }
+        memset(stat->time_in_state, 0, alloc_size);
+        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 = jiffies;
+        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);
+        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;
+
+        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 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;
+        }
+
+        for_each_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);
+        for_each_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);