// SPDX-License-Identifier: GPL-2.0-only
/*
 * TI SCI Generic Power Domain Driver
 *
 * Copyright (C) 2015-2017 Texas Instruments Incorporated - http://www.ti.com/
 *      J Keerthy <j-keerthy@ti.com>
 *      Dave Gerlach <d-gerlach@ti.com>
 */

#include <linux/err.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_domain.h>
#include <linux/pm_qos.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/soc/ti/ti_sci_protocol.h>
#include <dt-bindings/soc/ti,sci_pm_domain.h>

/**
 * struct ti_sci_genpd_provider: holds common TI SCI genpd provider data
 * @ti_sci: handle to TI SCI protocol driver that provides ops to
 *          communicate with system control processor.
 * @dev: pointer to dev for the driver for devm allocs
 * @pd_list: list of all the power domains on the device
 * @data: onecell data for genpd core
 */
struct ti_sci_genpd_provider {
        const struct ti_sci_handle *ti_sci;
        struct device *dev;
        struct list_head pd_list;
        struct genpd_onecell_data data;
};

/**
 * struct ti_sci_pm_domain: TI specific data needed for power domain
 * @idx: index of the device that identifies it with the system
 *       control processor.
 * @exclusive: Permissions for exclusive request or shared request of the
 *             device.
 * @pd: generic_pm_domain for use with the genpd framework
 * @node: link for the genpd list
 * @parent: link to the parent TI SCI genpd provider
 */
struct ti_sci_pm_domain {
        int idx;
        u8 exclusive;
        struct generic_pm_domain pd;
        struct list_head node;
        struct ti_sci_genpd_provider *parent;
};

#define genpd_to_ti_sci_pd(gpd) container_of(gpd, struct ti_sci_pm_domain, pd)

static inline bool ti_sci_pd_is_valid_constraint(s32 val)
{
        return val != PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
}

#ifdef CONFIG_PM_SLEEP
static void ti_sci_pd_set_lat_constraint(struct device *dev, s32 val)
{
        struct generic_pm_domain *genpd = pd_to_genpd(dev->pm_domain);
        struct ti_sci_pm_domain *pd = genpd_to_ti_sci_pd(genpd);
        const struct ti_sci_handle *ti_sci = pd->parent->ti_sci;
        u16 val_ms;
        int ret;

        /* PM QoS latency unit is usecs, TI SCI uses msecs */
        val_ms = val / USEC_PER_MSEC;
        ret = ti_sci->ops.pm_ops.set_latency_constraint(ti_sci, val_ms, TISCI_MSG_CONSTRAINT_SET);
        if (ret)
                dev_err(dev, "ti_sci_pd: set latency constraint failed: ret=%d\n",
                        ret);
        else
                dev_dbg(dev, "ti_sci_pd: ID:%d set latency constraint %d\n",
                        pd->idx, val);
}
#endif

static inline void ti_sci_pd_set_wkup_constraint(struct device *dev)
{
        struct generic_pm_domain *genpd = pd_to_genpd(dev->pm_domain);
        struct ti_sci_pm_domain *pd = genpd_to_ti_sci_pd(genpd);
        const struct ti_sci_handle *ti_sci = pd->parent->ti_sci;
        int ret;

        if (device_may_wakeup(dev)) {
                /*
                 * If device can wakeup using IO daisy chain wakeups,
                 * we do not want to set a constraint.
                 */
                if (dev->power.wakeirq) {
                        dev_dbg(dev, "%s: has wake IRQ, not setting constraints\n", __func__);
                        return;
                }

                ret = ti_sci->ops.pm_ops.set_device_constraint(ti_sci, pd->idx,
                                                               TISCI_MSG_CONSTRAINT_SET);
                if (!ret)
                        dev_dbg(dev, "ti_sci_pd: ID:%d set device constraint.\n", pd->idx);
        }
}

/*
 * ti_sci_pd_power_off(): genpd power down hook
 * @domain: pointer to the powerdomain to power off
 */
static int ti_sci_pd_power_off(struct generic_pm_domain *domain)
{
        struct ti_sci_pm_domain *pd = genpd_to_ti_sci_pd(domain);
        const struct ti_sci_handle *ti_sci = pd->parent->ti_sci;

        return ti_sci->ops.dev_ops.put_device(ti_sci, pd->idx);
}

/*
 * ti_sci_pd_power_on(): genpd power up hook
 * @domain: pointer to the powerdomain to power on
 */
static int ti_sci_pd_power_on(struct generic_pm_domain *domain)
{
        struct ti_sci_pm_domain *pd = genpd_to_ti_sci_pd(domain);
        const struct ti_sci_handle *ti_sci = pd->parent->ti_sci;

        if (pd->exclusive)
                return ti_sci->ops.dev_ops.get_device_exclusive(ti_sci,
                                                                pd->idx);
        else
                return ti_sci->ops.dev_ops.get_device(ti_sci, pd->idx);
}

#ifdef CONFIG_PM_SLEEP
static int ti_sci_pd_suspend(struct device *dev)
{
        int ret;
        s32 val;

        ret = pm_generic_suspend(dev);
        if (ret)
                return ret;

        val = dev_pm_qos_read_value(dev, DEV_PM_QOS_RESUME_LATENCY);
        if (ti_sci_pd_is_valid_constraint(val))
                ti_sci_pd_set_lat_constraint(dev, val);

        ti_sci_pd_set_wkup_constraint(dev);

        return 0;
}
#else
#define ti_sci_pd_suspend               NULL
#endif

/*
 * ti_sci_pd_xlate(): translation service for TI SCI genpds
 * @genpdspec: DT identification data for the genpd
 * @data: genpd core data for all the powerdomains on the device
 */
static struct generic_pm_domain *ti_sci_pd_xlate(
                                        const struct of_phandle_args *genpdspec,
                                        void *data)
{
        struct genpd_onecell_data *genpd_data = data;
        unsigned int idx = genpdspec->args[0];

        if (genpdspec->args_count != 1 && genpdspec->args_count != 2)
                return ERR_PTR(-EINVAL);

        if (idx >= genpd_data->num_domains) {
                pr_err("%s: invalid domain index %u\n", __func__, idx);
                return ERR_PTR(-EINVAL);
        }

        if (!genpd_data->domains[idx])
                return ERR_PTR(-ENOENT);

        genpd_to_ti_sci_pd(genpd_data->domains[idx])->exclusive =
                genpdspec->args[1];

        return genpd_data->domains[idx];
}

static const struct of_device_id ti_sci_pm_domain_matches[] = {
        { .compatible = "ti,sci-pm-domain", },
        { },
};
MODULE_DEVICE_TABLE(of, ti_sci_pm_domain_matches);

static bool ti_sci_pm_idx_exists(struct ti_sci_genpd_provider *pd_provider, u32 idx)
{
        struct ti_sci_pm_domain *pd;

        list_for_each_entry(pd, &pd_provider->pd_list, node) {
                if (pd->idx == idx)
                        return true;
        }

        return false;
}

static bool ti_sci_pm_pd_is_on(struct ti_sci_genpd_provider *pd_provider,
                               int pd_idx)
{
        bool is_on;
        int ret;

        if (!pd_provider->ti_sci->ops.dev_ops.is_on)
                return false;

        ret = pd_provider->ti_sci->ops.dev_ops.is_on(pd_provider->ti_sci,
                                                     pd_idx, NULL, &is_on);
        if (ret)
                return false;

        return is_on;
}

static int ti_sci_pm_domain_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct ti_sci_genpd_provider *pd_provider;
        struct ti_sci_pm_domain *pd;
        struct device_node *np __free(device_node) = NULL;
        struct of_phandle_args args;
        u32 max_id = 0;
        int index;

        pd_provider = devm_kzalloc(dev, sizeof(*pd_provider), GFP_KERNEL);
        if (!pd_provider)
                return -ENOMEM;

        pd_provider->ti_sci = devm_ti_sci_get_handle(dev);
        if (IS_ERR(pd_provider->ti_sci))
                return PTR_ERR(pd_provider->ti_sci);

        pd_provider->dev = dev;

        INIT_LIST_HEAD(&pd_provider->pd_list);

        /* Find highest device ID used for power domains */
        for_each_node_with_property(np, "power-domains") {
                index = 0;

                while (!of_parse_phandle_with_args(np, "power-domains",
                                                   "#power-domain-cells",
                                                   index, &args)) {

                        if (args.args_count >= 1 && args.np == dev->of_node) {
                                bool is_on;

                                of_node_put(args.np);
                                if (args.args[0] > max_id) {
                                        max_id = args.args[0];
                                } else {
                                        if (ti_sci_pm_idx_exists(pd_provider, args.args[0])) {
                                                index++;
                                                continue;
                                        }
                                }

                                pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
                                if (!pd)
                                        return -ENOMEM;

                                pd->pd.name = devm_kasprintf(dev, GFP_KERNEL,
                                                             "pd:%d",
                                                             args.args[0]);
                                if (!pd->pd.name)
                                        return -ENOMEM;

                                pd->pd.power_off = ti_sci_pd_power_off;
                                pd->pd.power_on = ti_sci_pd_power_on;
                                pd->pd.flags |= GENPD_FLAG_ACTIVE_WAKEUP;
                                pd->idx = args.args[0];
                                pd->parent = pd_provider;
                                /*
                                 * If SCI constraint functions are present, then firmware
                                 * supports the constraints API.
                                 */
                                if (pd_provider->ti_sci->ops.pm_ops.set_device_constraint &&
                                    pd_provider->ti_sci->ops.pm_ops.set_latency_constraint)
                                        pd->pd.domain.ops.suspend = ti_sci_pd_suspend;

                                is_on = ti_sci_pm_pd_is_on(pd_provider,
                                                           pd->idx);

                                pm_genpd_init(&pd->pd, NULL, !is_on);

                                list_add(&pd->node, &pd_provider->pd_list);
                        } else {
                                of_node_put(args.np);
                        }

                        index++;
                }
        }

        pd_provider->data.domains =
                devm_kcalloc(dev, max_id + 1,
                             sizeof(*pd_provider->data.domains),
                             GFP_KERNEL);
        if (!pd_provider->data.domains)
                return -ENOMEM;

        pd_provider->data.num_domains = max_id + 1;
        pd_provider->data.xlate = ti_sci_pd_xlate;

        list_for_each_entry(pd, &pd_provider->pd_list, node)
                pd_provider->data.domains[pd->idx] = &pd->pd;

        return of_genpd_add_provider_onecell(dev->of_node, &pd_provider->data);
}

static struct platform_driver ti_sci_pm_domains_driver = {
        .probe = ti_sci_pm_domain_probe,
        .driver = {
                .name = "ti_sci_pm_domains",
                .of_match_table = ti_sci_pm_domain_matches,
        },
};
module_platform_driver(ti_sci_pm_domains_driver);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("TI System Control Interface (SCI) Power Domain driver");
MODULE_AUTHOR("Dave Gerlach");