1 files changed, 426 insertions, 0 deletions

diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
new file mode 100644
index 00000000..72f0093a
--- /dev/null
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -0,0 +1,426 @@
+/*
+ *  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/slab.h>
+#include <linux/cpu.h>
+#include <linux/sysfs.h>
+#include <linux/cpufreq.h>
+#include <linux/module.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 DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
+
+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 = per_cpu(cpufreq_stats_table, cpu);
+	if (stat->time_in_state)
+		stat->time_in_state[stat->last_index] +=
+			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 = per_cpu(cpufreq_stats_table, policy->cpu);
+	if (!stat)
+		return 0;
+	return sprintf(buf, "%d\n",
+			per_cpu(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 = per_cpu(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 = per_cpu(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 PAGE_SIZE;
+
+	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]);
+		}
+		if (len >= PAGE_SIZE)
+			break;
+		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
+	}
+	if (len >= PAGE_SIZE)
+		return PAGE_SIZE;
+	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;
+}
+
+/* should be called late in the CPU removal sequence so that the stats
+ * memory is still available in case someone tries to use it.
+ */
+static void cpufreq_stats_free_table(unsigned int cpu)
+{
+	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
+	if (stat) {
+		kfree(stat->time_in_state);
+		kfree(stat);
+	}
+	per_cpu(cpufreq_stats_table, cpu) = NULL;
+}
+
+/* must be called early in the CPU removal sequence (before
+ * cpufreq_remove_dev) so that policy is still valid.
+ */
+static void cpufreq_stats_free_sysfs(unsigned int cpu)
+{
+	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
+	if (policy && policy->cpu == cpu)
+		sysfs_remove_group(&policy->kobj, &stats_attr_group);
+	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 (per_cpu(cpufreq_stats_table, cpu))
+		return -EBUSY;
+	stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL);
+	if ((stat) == NULL)
+		return -ENOMEM;
+
+	data = cpufreq_cpu_get(cpu);
+	if (data == NULL) {
+		ret = -EINVAL;
+		goto error_get_fail;
+	}
+
+	ret = sysfs_create_group(&data->kobj, &stats_attr_group);
+	if (ret)
+		goto error_out;
+
+	stat->cpu = cpu;
+	per_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);
+	per_cpu(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;
+	ret = cpufreq_stats_create_table(policy, table);
+	if (ret)
+		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 = per_cpu(cpufreq_stats_table, freq->cpu);
+	if (!stat)
+		return 0;
+
+	old_index = stat->last_index;
+	new_index = freq_table_get_index(stat, freq->new);
+
+	/* We can't do stat->time_in_state[-1]= .. */
+	if (old_index == -1 || new_index == -1)
+		return 0;
+
+	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 int cpufreq_stats_create_table_cpu(unsigned int cpu)
+{
+	struct cpufreq_policy *policy;
+	struct cpufreq_frequency_table *table;
+	int ret = -ENODEV;
+
+	policy = cpufreq_cpu_get(cpu);
+	if (!policy)
+		return -ENODEV;
+
+	table = cpufreq_frequency_get_table(cpu);
+	if (!table)
+		goto out;
+
+	ret = cpufreq_stats_create_table(policy, table);
+
+out:
+	cpufreq_cpu_put(policy);
+	return ret;
+}
+
+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_DOWN_PREPARE:
+		cpufreq_stats_free_sysfs(cpu);
+		break;
+	case CPU_DEAD:
+	case CPU_DEAD_FROZEN:
+		cpufreq_stats_free_table(cpu);
+		break;
+	case CPU_DOWN_FAILED:
+	case CPU_DOWN_FAILED_FROZEN:
+		cpufreq_stats_create_table_cpu(cpu);
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+/* priority=1 so this will get called before cpufreq_remove_dev */
+static struct notifier_block cpufreq_stat_cpu_notifier __refdata = {
+	.notifier_call = cpufreq_stat_cpu_callback,
+	.priority = 1,
+};
+
+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;
+
+	ret = cpufreq_register_notifier(&notifier_trans_block,
+				CPUFREQ_TRANSITION_NOTIFIER);
+	if (ret) {
+		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);
+		cpufreq_stats_free_sysfs(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);