1 files changed, 357 insertions, 0 deletions

diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
new file mode 100644
index 000000000..5e370a30a
--- /dev/null
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -0,0 +1,357 @@
+/*
+ *  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/cpu.h>
+#include <linux/cpufreq.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/cputime.h>
+
+static spinlock_t cpufreq_stats_lock;
+
+struct cpufreq_stats {
+	unsigned int total_trans;
+	unsigned long long last_time;
+	unsigned int max_state;
+	unsigned int state_num;
+	unsigned int last_index;
+	u64 *time_in_state;
+	unsigned int *freq_table;
+#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
+	unsigned int *trans_table;
+#endif
+};
+
+static int cpufreq_stats_update(struct cpufreq_stats *stats)
+{
+	unsigned long long cur_time = get_jiffies_64();
+
+	spin_lock(&cpufreq_stats_lock);
+	stats->time_in_state[stats->last_index] += cur_time - stats->last_time;
+	stats->last_time = cur_time;
+	spin_unlock(&cpufreq_stats_lock);
+	return 0;
+}
+
+static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
+{
+	return sprintf(buf, "%d\n", policy->stats->total_trans);
+}
+
+static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
+{
+	struct cpufreq_stats *stats = policy->stats;
+	ssize_t len = 0;
+	int i;
+
+	cpufreq_stats_update(stats);
+	for (i = 0; i < stats->state_num; i++) {
+		len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],
+			(unsigned long long)
+			jiffies_64_to_clock_t(stats->time_in_state[i]));
+	}
+	return len;
+}
+
+#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
+static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
+{
+	struct cpufreq_stats *stats = policy->stats;
+	ssize_t len = 0;
+	int i, j;
+
+	len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
+	len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
+	for (i = 0; i < stats->state_num; i++) {
+		if (len >= PAGE_SIZE)
+			break;
+		len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
+				stats->freq_table[i]);
+	}
+	if (len >= PAGE_SIZE)
+		return PAGE_SIZE;
+
+	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
+
+	for (i = 0; i < stats->state_num; i++) {
+		if (len >= PAGE_SIZE)
+			break;
+
+		len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
+				stats->freq_table[i]);
+
+		for (j = 0; j < stats->state_num; j++) {
+			if (len >= PAGE_SIZE)
+				break;
+			len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
+					stats->trans_table[i*stats->max_state+j]);
+		}
+		if (len >= PAGE_SIZE)
+			break;
+		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
+	}
+	if (len >= PAGE_SIZE)
+		return PAGE_SIZE;
+	return len;
+}
+cpufreq_freq_attr_ro(trans_table);
+#endif
+
+cpufreq_freq_attr_ro(total_trans);
+cpufreq_freq_attr_ro(time_in_state);
+
+static struct attribute *default_attrs[] = {
+	&total_trans.attr,
+	&time_in_state.attr,
+#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
+	&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 *stats, unsigned int freq)
+{
+	int index;
+	for (index = 0; index < stats->max_state; index++)
+		if (stats->freq_table[index] == freq)
+			return index;
+	return -1;
+}
+
+static void __cpufreq_stats_free_table(struct cpufreq_policy *policy)
+{
+	struct cpufreq_stats *stats = policy->stats;
+
+	/* Already freed */
+	if (!stats)
+		return;
+
+	pr_debug("%s: Free stats table\n", __func__);
+
+	sysfs_remove_group(&policy->kobj, &stats_attr_group);
+	kfree(stats->time_in_state);
+	kfree(stats);
+	policy->stats = NULL;
+}
+
+static void cpufreq_stats_free_table(unsigned int cpu)
+{
+	struct cpufreq_policy *policy;
+
+	policy = cpufreq_cpu_get(cpu);
+	if (!policy)
+		return;
+
+	__cpufreq_stats_free_table(policy);
+
+	cpufreq_cpu_put(policy);
+}
+
+static int __cpufreq_stats_create_table(struct cpufreq_policy *policy)
+{
+	unsigned int i = 0, count = 0, ret = -ENOMEM;
+	struct cpufreq_stats *stats;
+	unsigned int alloc_size;
+	unsigned int cpu = policy->cpu;
+	struct cpufreq_frequency_table *pos, *table;
+
+	/* We need cpufreq table for creating stats table */
+	table = cpufreq_frequency_get_table(cpu);
+	if (unlikely(!table))
+		return 0;
+
+	/* stats already initialized */
+	if (policy->stats)
+		return -EEXIST;
+
+	stats = kzalloc(sizeof(*stats), GFP_KERNEL);
+	if (!stats)
+		return -ENOMEM;
+
+	/* Find total allocation size */
+	cpufreq_for_each_valid_entry(pos, table)
+		count++;
+
+	alloc_size = count * sizeof(int) + count * sizeof(u64);
+
+#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
+	alloc_size += count * count * sizeof(int);
+#endif
+
+	/* Allocate memory for time_in_state/freq_table/trans_table in one go */
+	stats->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
+	if (!stats->time_in_state)
+		goto free_stat;
+
+	stats->freq_table = (unsigned int *)(stats->time_in_state + count);
+
+#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
+	stats->trans_table = stats->freq_table + count;
+#endif
+
+	stats->max_state = count;
+
+	/* Find valid-unique entries */
+	cpufreq_for_each_valid_entry(pos, table)
+		if (freq_table_get_index(stats, pos->frequency) == -1)
+			stats->freq_table[i++] = pos->frequency;
+
+	stats->state_num = i;
+	stats->last_time = get_jiffies_64();
+	stats->last_index = freq_table_get_index(stats, policy->cur);
+
+	policy->stats = stats;
+	ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
+	if (!ret)
+		return 0;
+
+	/* We failed, release resources */
+	policy->stats = NULL;
+	kfree(stats->time_in_state);
+free_stat:
+	kfree(stats);
+
+	return ret;
+}
+
+static void cpufreq_stats_create_table(unsigned int cpu)
+{
+	struct cpufreq_policy *policy;
+
+	/*
+	 * "likely(!policy)" because normally cpufreq_stats will be registered
+	 * before cpufreq driver
+	 */
+	policy = cpufreq_cpu_get(cpu);
+	if (likely(!policy))
+		return;
+
+	__cpufreq_stats_create_table(policy);
+
+	cpufreq_cpu_put(policy);
+}
+
+static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
+		unsigned long val, void *data)
+{
+	int ret = 0;
+	struct cpufreq_policy *policy = data;
+
+	if (val == CPUFREQ_CREATE_POLICY)
+		ret = __cpufreq_stats_create_table(policy);
+	else if (val == CPUFREQ_REMOVE_POLICY)
+		__cpufreq_stats_free_table(policy);
+
+	return ret;
+}
+
+static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
+		unsigned long val, void *data)
+{
+	struct cpufreq_freqs *freq = data;
+	struct cpufreq_policy *policy = cpufreq_cpu_get(freq->cpu);
+	struct cpufreq_stats *stats;
+	int old_index, new_index;
+
+	if (!policy) {
+		pr_err("%s: No policy found\n", __func__);
+		return 0;
+	}
+
+	if (val != CPUFREQ_POSTCHANGE)
+		goto put_policy;
+
+	if (!policy->stats) {
+		pr_debug("%s: No stats found\n", __func__);
+		goto put_policy;
+	}
+
+	stats = policy->stats;
+
+	old_index = stats->last_index;
+	new_index = freq_table_get_index(stats, freq->new);
+
+	/* We can't do stats->time_in_state[-1]= .. */
+	if (old_index == -1 || new_index == -1)
+		goto put_policy;
+
+	if (old_index == new_index)
+		goto put_policy;
+
+	cpufreq_stats_update(stats);
+
+	stats->last_index = new_index;
+#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
+	stats->trans_table[old_index * stats->max_state + new_index]++;
+#endif
+	stats->total_trans++;
+
+put_policy:
+	cpufreq_cpu_put(policy);
+	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);
+	ret = cpufreq_register_notifier(&notifier_policy_block,
+				CPUFREQ_POLICY_NOTIFIER);
+	if (ret)
+		return ret;
+
+	for_each_online_cpu(cpu)
+		cpufreq_stats_create_table(cpu);
+
+	ret = cpufreq_register_notifier(&notifier_trans_block,
+				CPUFREQ_TRANSITION_NOTIFIER);
+	if (ret) {
+		cpufreq_unregister_notifier(&notifier_policy_block,
+				CPUFREQ_POLICY_NOTIFIER);
+		for_each_online_cpu(cpu)
+			cpufreq_stats_free_table(cpu);
+		return ret;
+	}
+
+	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_online_cpu(cpu)
+		cpufreq_stats_free_table(cpu);
+}
+
+MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
+MODULE_DESCRIPTION("Export cpufreq stats via sysfs");
+MODULE_LICENSE("GPL");
+
+module_init(cpufreq_stats_init);
+module_exit(cpufreq_stats_exit);