/* Copyright (c) 2014-2018, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#define pr_fmt(fmt) "%s: " fmt, KBUILD_MODNAME

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/err.h>
#include <linux/sysfs.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/moduleparam.h>
#include "lpm-levels.h"

enum lpm_type {
	IDLE = 0,
	SUSPEND,
	LATENCY,
	LPM_TYPE_NR
};

struct lpm_type_str {
	enum lpm_type type;
	char *str;
};

static const struct lpm_type_str lpm_types[] = {
	{IDLE, "idle_enabled"},
	{SUSPEND, "suspend_enabled"},
	{LATENCY, "exit_latency_us"},
};

static struct lpm_level_avail *cpu_level_available[NR_CPUS];
static struct platform_device *lpm_pdev;

static void *get_enabled_ptr(struct kobj_attribute *attr,
					struct lpm_level_avail *avail)
{
	void *arg = NULL;

	if (!strcmp(attr->attr.name, lpm_types[IDLE].str))
		arg = (void *) &avail->idle_enabled;
	else if (!strcmp(attr->attr.name, lpm_types[SUSPEND].str))
		arg = (void *) &avail->suspend_enabled;

	return arg;
}

static struct lpm_level_avail *get_avail_ptr(struct kobject *kobj,
					struct kobj_attribute *attr)
{
	struct lpm_level_avail *avail = NULL;

	if (!strcmp(attr->attr.name, lpm_types[IDLE].str))
		avail = container_of(attr, struct lpm_level_avail,
					idle_enabled_attr);
	else if (!strcmp(attr->attr.name, lpm_types[SUSPEND].str))
		avail = container_of(attr, struct lpm_level_avail,
					suspend_enabled_attr);
	else if (!strcmp(attr->attr.name, lpm_types[LATENCY].str))
		avail = container_of(attr, struct lpm_level_avail,
					latency_attr);

	return avail;
}

static ssize_t lpm_latency_show(struct kobject *kobj,
		struct kobj_attribute *attr, char *buf)
{
	int ret = 0;
	struct kernel_param kp;
	struct lpm_level_avail *avail = get_avail_ptr(kobj, attr);

	if (WARN_ON(!avail))
		return -EINVAL;

	kp.arg = &avail->exit_latency;

	ret = param_get_uint(buf, &kp);
	if (ret > 0) {
		strlcat(buf, "\n", PAGE_SIZE);
		ret++;
	}

	return ret;
}

ssize_t lpm_enable_show(struct kobject *kobj, struct kobj_attribute *attr,
				char *buf)
{
	int ret = 0;
	struct kernel_param kp;
	struct lpm_level_avail *avail = get_avail_ptr(kobj, attr);

	if (WARN_ON(!avail))
		return -EINVAL;

	kp.arg = get_enabled_ptr(attr, avail);
	if (WARN_ON(!kp.arg))
		return -EINVAL;

	ret = param_get_bool(buf, &kp);
	if (ret > 0) {
		strlcat(buf, "\n", PAGE_SIZE);
		ret++;
	}

	return ret;
}

ssize_t lpm_enable_store(struct kobject *kobj, struct kobj_attribute *attr,
				const char *buf, size_t len)
{
	int ret = 0;
	struct kernel_param kp;
	struct lpm_level_avail *avail;

	avail = get_avail_ptr(kobj, attr);
	if (WARN_ON(!avail))
		return -EINVAL;

	kp.arg = get_enabled_ptr(attr, avail);
	ret = param_set_bool(buf, &kp);

	return ret ? ret : len;
}

static int create_lvl_avail_nodes(const char *name,
			struct kobject *parent, struct lpm_level_avail *avail,
			void *data, int index, bool cpu_node)
{
	struct attribute_group *attr_group = NULL;
	struct attribute **attr = NULL;
	struct kobject *kobj = NULL;
	int ret = 0;

	kobj = kobject_create_and_add(name, parent);
	if (!kobj)
		return -ENOMEM;

	attr_group = devm_kzalloc(&lpm_pdev->dev, sizeof(*attr_group),
					GFP_KERNEL);
	if (!attr_group) {
		ret = -ENOMEM;
		goto failed;
	}

	attr = devm_kzalloc(&lpm_pdev->dev,
		sizeof(*attr) * (LPM_TYPE_NR + 1), GFP_KERNEL);
	if (!attr) {
		ret = -ENOMEM;
		goto failed;
	}

	sysfs_attr_init(&avail->idle_enabled_attr.attr);
	avail->idle_enabled_attr.attr.name = lpm_types[IDLE].str;
	avail->idle_enabled_attr.attr.mode = 0644;
	avail->idle_enabled_attr.show = lpm_enable_show;
	avail->idle_enabled_attr.store = lpm_enable_store;

	sysfs_attr_init(&avail->suspend_enabled_attr.attr);
	avail->suspend_enabled_attr.attr.name = lpm_types[SUSPEND].str;
	avail->suspend_enabled_attr.attr.mode = 0644;
	avail->suspend_enabled_attr.show = lpm_enable_show;
	avail->suspend_enabled_attr.store = lpm_enable_store;

	sysfs_attr_init(&avail->latency_attr.attr);
	avail->latency_attr.attr.name = lpm_types[LATENCY].str;
	avail->latency_attr.attr.mode = 0444;
	avail->latency_attr.show = lpm_latency_show;
	avail->latency_attr.store = NULL;

	attr[0] = &avail->idle_enabled_attr.attr;
	attr[1] = &avail->suspend_enabled_attr.attr;
	attr[2] = &avail->latency_attr.attr;
	attr[3] = NULL;
	attr_group->attrs = attr;

	ret = sysfs_create_group(kobj, attr_group);
	if (ret) {
		ret = -ENOMEM;
		goto failed;
	}

	avail->idle_enabled = true;
	avail->suspend_enabled = true;
	avail->kobj = kobj;
	avail->data = data;
	avail->idx = index;
	avail->cpu_node = cpu_node;

	return ret;

failed:
	kobject_put(kobj);
	return ret;
}

static int create_cpu_lvl_nodes(struct lpm_cluster *p, struct kobject *parent)
{
	int cpu;
	int i, cpu_idx;
	struct kobject **cpu_kobj = NULL;
	struct lpm_level_avail *level_list = NULL;
	char cpu_name[20] = {0};
	int ret = 0;
	struct list_head *pos;

	cpu_kobj = devm_kzalloc(&lpm_pdev->dev, sizeof(*cpu_kobj) *
			cpumask_weight(&p->child_cpus), GFP_KERNEL);
	if (!cpu_kobj)
		return -ENOMEM;

	cpu_idx = 0;
	list_for_each(pos, &p->cpu) {
		struct lpm_cpu *lpm_cpu = list_entry(pos, struct lpm_cpu, list);

		for_each_cpu(cpu, &lpm_cpu->related_cpus) {
			snprintf(cpu_name, sizeof(cpu_name), "cpu%d", cpu);
			cpu_kobj[cpu_idx] = kobject_create_and_add(cpu_name,
					parent);
			if (!cpu_kobj[cpu_idx]) {
				ret = -ENOMEM;
				goto release_kobj;
			}

			level_list = devm_kzalloc(&lpm_pdev->dev,
					lpm_cpu->nlevels * sizeof(*level_list),
					GFP_KERNEL);
			if (!level_list) {
				ret = -ENOMEM;
				goto release_kobj;
			}

			/*
			 * Skip enable/disable for WFI. cpuidle expects WFI to
			 * be available at all times.
			 */
			for (i = 1; i < lpm_cpu->nlevels; i++) {
				level_list[i].exit_latency =
					p->levels[i].pwr.exit_latency;
				ret = create_lvl_avail_nodes(
						lpm_cpu->levels[i].name,
						cpu_kobj[cpu_idx],
						&level_list[i],
						(void *)lpm_cpu, cpu, true);
				if (ret)
					goto release_kobj;
			}

			cpu_level_available[cpu] = level_list;
			cpu_idx++;
		}
	}

	return ret;

release_kobj:
	for (i = 0; i < cpumask_weight(&p->child_cpus); i++)
		kobject_put(cpu_kobj[i]);

	return ret;
}

int create_cluster_lvl_nodes(struct lpm_cluster *p, struct kobject *kobj)
{
	int ret = 0;
	struct lpm_cluster *child = NULL;
	int i;
	struct kobject *cluster_kobj = NULL;

	if (!p)
		return -ENODEV;

	cluster_kobj = kobject_create_and_add(p->cluster_name, kobj);
	if (!cluster_kobj)
		return -ENOMEM;

	for (i = 0; i < p->nlevels; i++) {
		p->levels[i].available.exit_latency =
					p->levels[i].pwr.exit_latency;
		ret = create_lvl_avail_nodes(p->levels[i].level_name,
				cluster_kobj, &p->levels[i].available,
				(void *)p, 0, false);
		if (ret)
			return ret;
	}

	list_for_each_entry(child, &p->child, list) {
		ret = create_cluster_lvl_nodes(child, cluster_kobj);
		if (ret)
			return ret;
	}

	if (!list_empty(&p->cpu)) {
		ret = create_cpu_lvl_nodes(p, cluster_kobj);
		if (ret)
			return ret;
	}

	return ret;
}

bool lpm_cpu_mode_allow(unsigned int cpu,
		unsigned int index, bool from_idle)
{
	struct lpm_level_avail *avail = cpu_level_available[cpu];

	if (lpm_pdev && !index)
		return 1;

	if (!lpm_pdev || !avail)
		return !from_idle;

	return !!(from_idle ? avail[index].idle_enabled :
				avail[index].suspend_enabled);
}

bool lpm_cluster_mode_allow(struct lpm_cluster *cluster,
		unsigned int mode, bool from_idle)
{
	struct lpm_level_avail *avail = &cluster->levels[mode].available;

	if (!lpm_pdev || !avail)
		return false;

	return !!(from_idle ? avail->idle_enabled :
				avail->suspend_enabled);
}

static int parse_cluster_params(struct device_node *node,
		struct lpm_cluster *c)
{
	char *key;
	int ret;

	key = "label";
	ret = of_property_read_string(node, key, &c->cluster_name);
	if (ret)
		goto fail;

	key = "qcom,psci-mode-shift";
	ret = of_property_read_u32(node, key, &c->psci_mode_shift);
	if (ret)
		goto fail;

	key = "qcom,psci-mode-mask";
	ret = of_property_read_u32(node, key, &c->psci_mode_mask);
	if (ret)
		goto fail;

	key = "qcom,disable-prediction";
	c->lpm_prediction = !(of_property_read_bool(node, key));

	if (c->lpm_prediction) {
		key = "qcom,clstr-tmr-add";
		ret = of_property_read_u32(node, key, &c->tmr_add);
		if (ret || c->tmr_add < TIMER_ADD_LOW ||
					c->tmr_add > TIMER_ADD_HIGH)
			c->tmr_add = DEFAULT_TIMER_ADD;
	}

	/* Set default_level to 0 as default */
	c->default_level = 0;

	return 0;
fail:
	pr_err("Failed to read key: %s ret: %d\n", key, ret);

	return ret;
}

static int parse_power_params(struct device_node *node,
		struct power_params *pwr)
{
	char *key;
	int ret;

	key = "qcom,entry-latency-us";
	ret  = of_property_read_u32(node, key, &pwr->entry_latency);
	if (ret)
		goto fail;

	key = "qcom,exit-latency-us";
	ret  = of_property_read_u32(node, key, &pwr->exit_latency);
	if (ret)
		goto fail;

	key = "qcom,min-residency-us";
	ret = of_property_read_u32(node, key, &pwr->min_residency);
	if (ret)
		goto fail;

	return ret;
fail:
	pr_err("Failed to read key: %s node: %s\n", key, node->name);

	return ret;
}

static int parse_cluster_level(struct device_node *node,
		struct lpm_cluster *cluster)
{
	struct lpm_cluster_level *level = &cluster->levels[cluster->nlevels];
	int ret = -ENOMEM;
	char *key;

	key = "label";
	ret = of_property_read_string(node, key, &level->level_name);
	if (ret)
		goto failed;

	key = "qcom,psci-mode";
	ret = of_property_read_u32(node, key, &level->psci_id);
	if (ret)
		goto failed;

	level->is_reset = of_property_read_bool(node, "qcom,is-reset");

	if (cluster->nlevels != cluster->default_level) {
		key = "qcom,min-child-idx";
		ret = of_property_read_u32(node, key, &level->min_child_level);
		if (ret)
			goto failed;

		if (cluster->min_child_level > level->min_child_level)
			cluster->min_child_level = level->min_child_level;
	}

	level->notify_rpm = of_property_read_bool(node, "qcom,notify-rpm");

	key = "parse_power_params";
	ret = parse_power_params(node, &level->pwr);
	if (ret)
		goto failed;

	key = "qcom,reset-level";
	ret = of_property_read_u32(node, key, &level->reset_level);
	if (ret == -EINVAL)
		level->reset_level = LPM_RESET_LVL_NONE;
	else if (ret)
		goto failed;

	cluster->nlevels++;

	return 0;
failed:
	pr_err("Failed to read key: %s ret: %d\n", key, ret);

	return ret;
}

static int parse_cpu_mode(struct device_node *n, struct lpm_cpu_level *l)
{
	char *key;
	int ret;

	key = "label";
	ret = of_property_read_string(n, key, &l->name);
	if (ret)
		goto fail;

	key = "qcom,psci-cpu-mode";
	ret = of_property_read_u32(n, key, &l->psci_id);
	if (ret)
		goto fail;

	return ret;
fail:
	pr_err("Failed to read key: %s level: %s\n", key, l->name);

	return ret;
}

static int get_cpumask_for_node(struct device_node *node, struct cpumask *mask)
{
	struct device_node *cpu_node;
	int cpu;
	int idx = 0;

	cpu_node = of_parse_phandle(node, "qcom,cpu", idx++);
	if (!cpu_node) {
		pr_info("%s: No CPU phandle, assuming single cluster\n",
				node->full_name);
		/*
		 * Not all targets have the cpu node populated in the device
		 * tree. If cpu node is not populated assume all possible
		 * nodes belong to this cluster
		 */
		cpumask_copy(mask, cpu_possible_mask);
		return 0;
	}

	while (cpu_node) {
		for_each_possible_cpu(cpu) {
			if (of_get_cpu_node(cpu, NULL) == cpu_node) {
				cpumask_set_cpu(cpu, mask);
				break;
			}
		}
		of_node_put(cpu_node);
		cpu_node = of_parse_phandle(node, "qcom,cpu", idx++);
	}

	return 0;
}

static int parse_cpu(struct device_node *node, struct lpm_cpu *cpu)
{

	struct device_node *n;
	int ret, i;
	const char *key;

	for_each_child_of_node(node, n) {
		struct lpm_cpu_level *l = &cpu->levels[cpu->nlevels];

		cpu->nlevels++;

		ret = parse_cpu_mode(n, l);
		if (ret) {
			of_node_put(n);
			return ret;
		}

		ret = parse_power_params(n, &l->pwr);
		if (ret) {
			of_node_put(n);
			return ret;
		}
		key = "qcom,use-broadcast-timer";
		l->use_bc_timer = of_property_read_bool(n, key);

		key = "qcom,is-reset";
		l->is_reset = of_property_read_bool(n, key);

		key = "qcom,reset-level";
		ret = of_property_read_u32(n, key, &l->reset_level);
		of_node_put(n);
		if (ret == -EINVAL)
			l->reset_level = LPM_RESET_LVL_NONE;
		else if (ret)
			return ret;
	}

	for (i = 1; i < cpu->nlevels; i++)
		cpu->levels[i-1].pwr.max_residency =
			cpu->levels[i].pwr.min_residency - 1;

	cpu->levels[i-1].pwr.max_residency = UINT_MAX;

	return 0;
}

static int parse_cpu_levels(struct device_node *node, struct lpm_cluster *c)
{
	int ret;
	char *key;
	struct lpm_cpu *cpu;

	cpu = devm_kzalloc(&lpm_pdev->dev, sizeof(*cpu), GFP_KERNEL);
	if (!cpu)
		return -ENOMEM;

	if (get_cpumask_for_node(node, &cpu->related_cpus))
		return -EINVAL;

	cpu->parent = c;

	key = "qcom,psci-mode-shift";
	ret = of_property_read_u32(node, key, &cpu->psci_mode_shift);
	if (ret)
		goto failed;

	key = "qcom,psci-mode-mask";
	ret = of_property_read_u32(node, key, &cpu->psci_mode_mask);
	if (ret)
		goto failed;

	key = "qcom,disable-prediction";
	cpu->lpm_prediction = !(of_property_read_bool(node, key));

	if (cpu->lpm_prediction) {
		key = "qcom,ref-stddev";
		ret = of_property_read_u32(node, key, &cpu->ref_stddev);
		if (ret || cpu->ref_stddev < STDDEV_LOW ||
					cpu->ref_stddev > STDDEV_HIGH)
			cpu->ref_stddev = DEFAULT_STDDEV;

		key = "qcom,tmr-add";
		ret = of_property_read_u32(node, key, &cpu->tmr_add);
		if (ret || cpu->tmr_add < TIMER_ADD_LOW ||
					cpu->tmr_add > TIMER_ADD_HIGH)
			cpu->tmr_add = DEFAULT_TIMER_ADD;

		key = "qcom,ref-premature-cnt";
		ret = of_property_read_u32(node, key, &cpu->ref_premature_cnt);
		if (ret || cpu->ref_premature_cnt < PREMATURE_CNT_LOW ||
				cpu->ref_premature_cnt > PREMATURE_CNT_HIGH)
			cpu->ref_premature_cnt = DEFAULT_PREMATURE_CNT;
	}

	key = "parse_cpu";
	ret = parse_cpu(node, cpu);
	if (ret)
		goto failed;

	cpumask_or(&c->child_cpus, &c->child_cpus, &cpu->related_cpus);
	list_add(&cpu->list, &c->cpu);

	return ret;

failed:
	pr_err("Failed to read key: %s node: %s\n", key, node->name);
	return ret;
}

void free_cluster_node(struct lpm_cluster *cluster)
{
	struct lpm_cpu *cpu, *n;
	struct lpm_cluster *cl, *m;

	list_for_each_entry_safe(cl, m, &cluster->child, list) {
		list_del(&cl->list);
		free_cluster_node(cl);
	};

	list_for_each_entry_safe(cpu, n, &cluster->cpu, list)
		list_del(&cpu->list);
}

/*
 * TODO:
 * Expects a CPU or a cluster only. This ensures that affinity
 * level of a cluster is consistent with reference to its
 * child nodes.
 */
struct lpm_cluster *parse_cluster(struct device_node *node,
		struct lpm_cluster *parent)
{
	struct lpm_cluster *c;
	struct device_node *n;
	char *key;
	int ret = 0, i;

	c = devm_kzalloc(&lpm_pdev->dev, sizeof(*c), GFP_KERNEL);
	if (!c)
		return ERR_PTR(-ENOMEM);

	ret = parse_cluster_params(node, c);
	if (ret)
		return NULL;

	INIT_LIST_HEAD(&c->child);
	INIT_LIST_HEAD(&c->cpu);
	c->parent = parent;
	spin_lock_init(&c->sync_lock);
	c->min_child_level = NR_LPM_LEVELS;

	for_each_child_of_node(node, n) {

		if (!n->name) {
			of_node_put(n);
			continue;
		}

		if (!of_node_cmp(n->name, "qcom,pm-cluster-level")) {
			key = "qcom,pm-cluster-level";
			if (parse_cluster_level(n, c))
				goto failed_parse_cluster;
		} else if (!of_node_cmp(n->name, "qcom,pm-cluster")) {
			struct lpm_cluster *child;

			key = "qcom,pm-cluster";
			child = parse_cluster(n, c);
			if (!child)
				goto failed_parse_cluster;

			list_add(&child->list, &c->child);
			cpumask_or(&c->child_cpus, &c->child_cpus,
					&child->child_cpus);
			c->aff_level = child->aff_level + 1;
		} else if (!of_node_cmp(n->name, "qcom,pm-cpu")) {
			key = "qcom,pm-cpu";
			if (parse_cpu_levels(n, c))
				goto failed_parse_cluster;

			c->aff_level = 1;
		}

		of_node_put(n);
	}

	if (cpumask_intersects(&c->child_cpus, cpu_online_mask))
		c->last_level = c->default_level;
	else
		c->last_level = c->nlevels-1;

	for (i = 1; i < c->nlevels; i++)
		c->levels[i-1].pwr.max_residency =
			c->levels[i].pwr.min_residency - 1;

	c->levels[i-1].pwr.max_residency = UINT_MAX;

	return c;

failed_parse_cluster:
	pr_err("Failed parse cluster:%s\n", key);
	of_node_put(n);
	if (parent)
		list_del(&c->list);
	free_cluster_node(c);
	return NULL;
}

struct lpm_cluster *lpm_of_parse_cluster(struct platform_device *pdev)
{
	struct device_node *top = NULL;
	struct lpm_cluster *c;

	top = of_find_node_by_name(pdev->dev.of_node, "qcom,pm-cluster");
	if (!top) {
		pr_err("Failed to find root node\n");
		return ERR_PTR(-ENODEV);
	}

	lpm_pdev = pdev;
	c = parse_cluster(top, NULL);
	of_node_put(top);
	return c;
}

void cluster_dt_walkthrough(struct lpm_cluster *cluster)
{
	struct list_head *list;
	struct lpm_cpu *cpu;
	int i, j;
	static int id;
	char str[10] = {0};

	if (!cluster)
		return;

	for (i = 0; i < id; i++)
		snprintf(str+i, 10 - i, "\t");
	pr_info("%d\n", __LINE__);

	for (i = 0; i < cluster->nlevels; i++) {
		struct lpm_cluster_level *l = &cluster->levels[i];
		pr_info("cluster: %s \t level: %s\n", cluster->cluster_name,
							l->level_name);
	}

	list_for_each_entry(cpu, &cluster->cpu, list) {
		pr_info("%d\n", __LINE__);
		for (j = 0; j < cpu->nlevels; j++)
			pr_info("%s\tCPU level name: %s\n", str,
						cpu->levels[j].name);
	}

	id++;

	list_for_each(list, &cluster->child) {
		struct lpm_cluster *n;

		pr_info("%d\n", __LINE__);
		n = list_entry(list, typeof(*n), list);
		cluster_dt_walkthrough(n);
	}
	id--;
}