/*
 * Copyright (c) 2016-2017, NVIDIA CORPORATION. All rights reserved
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.
 */

#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_domain.h>
#include <linux/slab.h>
#include <linux/version.h>

#include <soc/tegra/bpmp.h>
#include <soc/tegra/bpmp-abi.h>

struct tegra_powergate_info {
	unsigned int id;
	char *name;
};

struct tegra_powergate {
	struct generic_pm_domain genpd;
	struct tegra_bpmp *bpmp;
	unsigned int id;
};

static inline struct tegra_powergate *
to_tegra_powergate(struct generic_pm_domain *genpd)
{
	return container_of(genpd, struct tegra_powergate, genpd);
}

static int tegra_bpmp_powergate_set_state(struct tegra_bpmp *bpmp,
					  unsigned int id, u32 state)
{
	struct mrq_pg_request request;
	struct tegra_bpmp_message msg;

	memset(&request, 0, sizeof(request));
	request.cmd = CMD_PG_SET_STATE;
	request.id = id;
	request.set_state.state = state;

	memset(&msg, 0, sizeof(msg));
	msg.mrq = MRQ_PG;
	msg.tx.data = &request;
	msg.tx.size = sizeof(request);

	return tegra_bpmp_transfer(bpmp, &msg);
}

static int tegra_bpmp_powergate_get_state(struct tegra_bpmp *bpmp,
					  unsigned int id)
{
	struct mrq_pg_response response;
	struct mrq_pg_request request;
	struct tegra_bpmp_message msg;
	int err;

	memset(&request, 0, sizeof(request));
	request.cmd = CMD_PG_GET_STATE;
	request.id = id;

	memset(&response, 0, sizeof(response));

	memset(&msg, 0, sizeof(msg));
	msg.mrq = MRQ_PG;
	msg.tx.data = &request;
	msg.tx.size = sizeof(request);
	msg.rx.data = &response;
	msg.rx.size = sizeof(response);

	err = tegra_bpmp_transfer(bpmp, &msg);
	if (err < 0)
		return PG_STATE_OFF;

	return response.get_state.state;
}

static int tegra_bpmp_powergate_get_max_id(struct tegra_bpmp *bpmp)
{
	struct mrq_pg_response response;
	struct mrq_pg_request request;
	struct tegra_bpmp_message msg;
	int err;

	memset(&request, 0, sizeof(request));
	request.cmd = CMD_PG_GET_MAX_ID;

	memset(&response, 0, sizeof(response));

	memset(&msg, 0, sizeof(msg));
	msg.mrq = MRQ_PG;
	msg.tx.data = &request;
	msg.tx.size = sizeof(request);
	msg.rx.data = &response;
	msg.rx.size = sizeof(response);

	err = tegra_bpmp_transfer(bpmp, &msg);
	if (err < 0)
		return err;

	return response.get_max_id.max_id;
}

static char *tegra_bpmp_powergate_get_name(struct tegra_bpmp *bpmp,
					   unsigned int id)
{
	struct mrq_pg_response response;
	struct mrq_pg_request request;
	struct tegra_bpmp_message msg;
	int err;

	memset(&request, 0, sizeof(request));
	request.cmd = CMD_PG_GET_NAME;
	request.id = id;

	memset(&response, 0, sizeof(response));

	memset(&msg, 0, sizeof(msg));
	msg.mrq = MRQ_PG;
	msg.tx.data = &request;
	msg.tx.size = sizeof(request);
	msg.rx.data = &response;
	msg.rx.size = sizeof(response);

	err = tegra_bpmp_transfer(bpmp, &msg);
	if (err < 0)
		return NULL;

	return kstrdup(response.get_name.name, GFP_KERNEL);
}

static inline bool tegra_bpmp_powergate_is_powered(struct tegra_bpmp *bpmp,
						   unsigned int id)
{
	return tegra_bpmp_powergate_get_state(bpmp, id) != PG_STATE_OFF;
}

static int tegra_powergate_power_on(struct generic_pm_domain *domain)
{
	struct tegra_powergate *powergate = to_tegra_powergate(domain);
	struct tegra_bpmp *bpmp = powergate->bpmp;

	return tegra_bpmp_powergate_set_state(bpmp, powergate->id,
					      PG_STATE_ON);
}

static int tegra_powergate_power_off(struct generic_pm_domain *domain)
{
	struct tegra_powergate *powergate = to_tegra_powergate(domain);
	struct tegra_bpmp *bpmp = powergate->bpmp;

	return tegra_bpmp_powergate_set_state(bpmp, powergate->id,
					      PG_STATE_OFF);
}

static struct tegra_powergate *
tegra_powergate_add(struct tegra_bpmp *bpmp,
		    const struct tegra_powergate_info *info)
{
	struct tegra_powergate *powergate;
	bool off;
	int err;

	off = !tegra_bpmp_powergate_is_powered(bpmp, info->id);

	powergate = devm_kzalloc(bpmp->dev, sizeof(*powergate), GFP_KERNEL);
	if (!powergate)
		return ERR_PTR(-ENOMEM);

	powergate->id = info->id;
	powergate->bpmp = bpmp;

	powergate->genpd.name = kstrdup(info->name, GFP_KERNEL);
	powergate->genpd.power_on = tegra_powergate_power_on;
	powergate->genpd.power_off = tegra_powergate_power_off;

	err = pm_genpd_init(&powergate->genpd, NULL, off);
	if (err < 0) {
		kfree(powergate->genpd.name);
		return ERR_PTR(err);
	}

	return powergate;
}

static void tegra_powergate_remove(struct tegra_powergate *powergate)
{
	struct generic_pm_domain *genpd = &powergate->genpd;
	struct tegra_bpmp *bpmp = powergate->bpmp;
	int err;

	err = pm_genpd_remove(genpd);
	if (err < 0)
		dev_err(bpmp->dev, "failed to remove power domain %s: %d\n",
			genpd->name, err);

	kfree(genpd->name);
}

static int
tegra_bpmp_probe_powergates(struct tegra_bpmp *bpmp,
			    struct tegra_powergate_info **powergatesp)
{
	struct tegra_powergate_info *powergates;
	unsigned int max_id, id, count = 0;
	unsigned int num_holes = 0;
	int err;

	err = tegra_bpmp_powergate_get_max_id(bpmp);
	if (err < 0)
		return err;

	max_id = err;

	dev_dbg(bpmp->dev, "maximum powergate ID: %u\n", max_id);

	powergates = kcalloc(max_id + 1, sizeof(*powergates), GFP_KERNEL);
	if (!powergates)
		return -ENOMEM;

	for (id = 0; id <= max_id; id++) {
		struct tegra_powergate_info *info = &powergates[count];

		info->name = tegra_bpmp_powergate_get_name(bpmp, id);
		if (!info->name || info->name[0] == '\0') {
			num_holes++;
			continue;
		}

		info->id = id;
		count++;
	}

	dev_dbg(bpmp->dev, "holes: %u\n", num_holes);

	*powergatesp = powergates;

	return count;
}

static int tegra_bpmp_add_powergates(struct tegra_bpmp *bpmp,
				     struct tegra_powergate_info *powergates,
				     unsigned int count)
{
	struct genpd_onecell_data *genpd = &bpmp->genpd;
	struct generic_pm_domain **domains;
	struct tegra_powergate *powergate;
	unsigned int i;
	int err;

	domains = kcalloc(count, sizeof(*domains), GFP_KERNEL);
	if (!domains)
		return -ENOMEM;

	for (i = 0; i < count; i++) {
		powergate = tegra_powergate_add(bpmp, &powergates[i]);
		if (IS_ERR(powergate)) {
			err = PTR_ERR(powergate);
			goto remove;
		}

		dev_dbg(bpmp->dev, "added power domain %s\n",
			powergate->genpd.name);
		domains[i] = &powergate->genpd;
	}

	genpd->num_domains = count;
	genpd->domains = domains;

	return 0;

remove:
	while (i--) {
		powergate = to_tegra_powergate(domains[i]);
		tegra_powergate_remove(powergate);
	}

	kfree(genpd->domains);
	return err;
}

static void tegra_bpmp_remove_powergates(struct tegra_bpmp *bpmp)
{
	struct genpd_onecell_data *genpd = &bpmp->genpd;
	unsigned int i = genpd->num_domains;
	struct tegra_powergate *powergate;

	while (i--) {
		dev_dbg(bpmp->dev, "removing power domain %s\n",
			genpd->domains[i]->name);
		powergate = to_tegra_powergate(genpd->domains[i]);
		tegra_powergate_remove(powergate);
	}
}

static struct generic_pm_domain *
tegra_powergate_xlate(struct of_phandle_args *spec, void *data)
{
	struct generic_pm_domain *domain = ERR_PTR(-ENOENT);
	struct genpd_onecell_data *genpd = data;
	unsigned int i;

	for (i = 0; i < genpd->num_domains; i++) {
		struct tegra_powergate *powergate;

		powergate = to_tegra_powergate(genpd->domains[i]);
		if (powergate->id == spec->args[0]) {
			domain = &powergate->genpd;
			break;
		}
	}

	return domain;
}

int tegra_bpmp_init_powergates(struct tegra_bpmp *bpmp)
{
	struct device_node *np = bpmp->dev->of_node;
	struct tegra_powergate_info *powergates;
	struct device *dev = bpmp->dev;
	unsigned int count, i;
	int err;

	err = tegra_bpmp_probe_powergates(bpmp, &powergates);
	if (err < 0)
		return err;

	count = err;

	dev_dbg(dev, "%u power domains probed\n", count);

	err = tegra_bpmp_add_powergates(bpmp, powergates, count);
	if (err < 0)
		goto free;

	bpmp->genpd.xlate = tegra_powergate_xlate;

	err = of_genpd_add_provider_onecell(np, &bpmp->genpd);
	if (err < 0) {
		dev_err(dev, "failed to add power domain provider: %d\n", err);
		tegra_bpmp_remove_powergates(bpmp);
	}

free:
	for (i = 0; i < count; i++)
		kfree(powergates[i].name);

	kfree(powergates);
	return err;
}