/*
 *  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/of.h>
#include <linux/sched.h>
#include <linux/cputime.h>
#include <asm/smp_plat.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
};

struct cpufreq_power_stats {
	unsigned int state_num;
	unsigned int *curr;
	unsigned int *freq_table;
};

static DEFINE_PER_CPU(struct cpufreq_power_stats *, cpufreq_power_stats);

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;
}

void acct_update_power(struct task_struct *task, cputime_t cputime) {
	struct cpufreq_power_stats *powerstats;
	struct cpufreq_stats *stats;
	struct cpufreq_policy *policy;
	unsigned int cpu_num, curr;

	if (!task)
		return;

	cpu_num = task_cpu(task);

	policy = cpufreq_cpu_get(cpu_num);

	if (WARN_ON_ONCE(!policy))
		return;

	powerstats = per_cpu(cpufreq_power_stats, cpu_num);
	stats = policy->stats;
	if (!powerstats || !stats)
		return;

	curr = powerstats->curr[stats->last_index];
	task->cpu_power += curr * cputime_to_usecs(cputime);
	if (task->cpu_power != ULLONG_MAX)
		task->cpu_power += curr * cputime_to_usecs(cputime);
}
EXPORT_SYMBOL_GPL(acct_update_power);

static ssize_t show_current_in_state(struct kobject *kobj,
		struct kobj_attribute *attr, char *buf)
{
	ssize_t len = 0;
	unsigned int i, cpu;
	struct cpufreq_power_stats *powerstats;

	spin_lock(&cpufreq_stats_lock);
	for_each_possible_cpu(cpu) {
		powerstats = per_cpu(cpufreq_power_stats, cpu);
		if (!powerstats)
			continue;
		len += scnprintf(buf + len, PAGE_SIZE - len, "CPU%d:", cpu);
		for (i = 0; i < powerstats->state_num; i++)
			len += scnprintf(buf + len, PAGE_SIZE - len,
					"%d=%d ", powerstats->freq_table[i],
					powerstats->curr[i]);
		len += scnprintf(buf + len, PAGE_SIZE - len, "\n");
	}
	spin_unlock(&cpufreq_stats_lock);
	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 struct kobj_attribute _attr_current_in_state = __ATTR(current_in_state,
		0444, show_current_in_state, NULL);

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 void cpufreq_powerstats_free(void)
{
	int cpu;
	struct cpufreq_power_stats *powerstats;

	sysfs_remove_file(cpufreq_global_kobject, &_attr_current_in_state.attr);

	for_each_possible_cpu(cpu) {
		powerstats = per_cpu(cpufreq_power_stats, cpu);
		if (!powerstats)
			continue;
		kfree(powerstats->curr);
		kfree(powerstats);
		per_cpu(cpufreq_power_stats, cpu) = NULL;
	}
}

static int __cpufreq_stats_create_table(struct cpufreq_policy *policy,
		struct cpufreq_frequency_table *table, int count)
{
	unsigned int i = 0, ret = -ENOMEM;
	struct cpufreq_stats *stats;
	unsigned int alloc_size;
	struct cpufreq_frequency_table *pos;

	/* stats already initialized */
	if (policy->stats)
		return -EEXIST;

	stats = kzalloc(sizeof(*stats), GFP_KERNEL);
	if (!stats)
		return -ENOMEM;

	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_powerstats_create(unsigned int cpu,
		struct cpufreq_frequency_table *table, int count) {
	unsigned int alloc_size, i = 0, ret = 0;
	struct cpufreq_power_stats *powerstats;
	struct cpufreq_frequency_table *pos;
	struct device_node *cpu_node;
	char device_path[16];

	powerstats = kzalloc(sizeof(struct cpufreq_power_stats),
			GFP_KERNEL);
	if (!powerstats)
		return;

	/* Allocate memory for freq table per cpu as well as clockticks per
	 * freq*/
	alloc_size = count * sizeof(unsigned int) +
		count * sizeof(unsigned int);
	powerstats->curr = kzalloc(alloc_size, GFP_KERNEL);
	if (!powerstats->curr) {
		kfree(powerstats);
		return;
	}
	powerstats->freq_table = powerstats->curr + count;

	spin_lock(&cpufreq_stats_lock);
	i = 0;
	cpufreq_for_each_valid_entry(pos, table)
		powerstats->freq_table[i++] = pos->frequency;
	powerstats->state_num = i;

	snprintf(device_path, sizeof(device_path), "/cpus/cpu@%x", (int)cpu_logical_map(cpu));
	cpu_node = of_find_node_by_path(device_path);
	if (cpu_node) {
		ret = of_property_read_u32_array(cpu_node, "current",
				powerstats->curr, count);
		if (ret) {
			kfree(powerstats->curr);
			kfree(powerstats);
			powerstats = NULL;
		}
	}
	per_cpu(cpufreq_power_stats, cpu) = powerstats;
	spin_unlock(&cpufreq_stats_lock);
}

static void cpufreq_stats_create_table(unsigned int cpu)
{
	struct cpufreq_policy *policy;
	struct cpufreq_frequency_table *table, *pos;
	int count = 0;

	/*
	 * "likely(!policy)" because normally cpufreq_stats will be registered
	 * before cpufreq driver
	 */
	policy = cpufreq_cpu_get(cpu);
	if (likely(!policy))
		return;

	table = cpufreq_frequency_get_table(policy->cpu);
	if (likely(table)) {
		cpufreq_for_each_valid_entry(pos, table)
			count++;

		if (!per_cpu(cpufreq_power_stats, cpu))
			cpufreq_powerstats_create(cpu, table, count);

		__cpufreq_stats_create_table(policy, table, count);
	}

	cpufreq_cpu_put(policy);
}

#ifdef CONFIG_SCHED_HMP
extern struct cpumask hmp_slow_cpu_mask;
extern struct cpumask hmp_fast_cpu_mask;
#endif

static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
		unsigned long val, void *data)
{
	int ret = 0, count = 0;
	struct cpufreq_policy *policy = data;
	struct cpufreq_frequency_table *table, *pos;
	unsigned int cpu_num, cpu = policy->cpu;
#ifdef CONFIG_SCHED_HMP
	struct cpumask hmp_cpu_mask;
#endif


	table = cpufreq_frequency_get_table(cpu);
	if (!table)
		return 0;

	cpufreq_for_each_valid_entry(pos, table)
		count++;

#ifdef CONFIG_SCHED_HMP
	cpu_num = cpu;
	cpumask_and(&hmp_cpu_mask, cpu_coregroup_mask(cpu_num), cpu_online_mask);
	for_each_cpu(cpu_num, &hmp_cpu_mask) {
		if (!per_cpu(cpufreq_power_stats, cpu_num))
			cpufreq_powerstats_create(cpu_num, table, count);
	}
#else
	for_each_possible_cpu(cpu_num) {
		if (!per_cpu(cpufreq_power_stats, cpu_num))
			cpufreq_powerstats_create(cpu_num, table, count);
	}
#endif
	if (val == CPUFREQ_CREATE_POLICY)
		ret = __cpufreq_stats_create_table(policy, table, count);
	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;
	}

	ret = sysfs_create_file(cpufreq_global_kobject,
			&_attr_current_in_state.attr);
	if (ret)
		pr_warn("Cannot create sysfs file for cpufreq current stats\n");

	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);

	cpufreq_powerstats_free();
}

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);