// SPDX-License-Identifier: GPL-2.0-only
/*
 * OMAP Display Subsystem Base
 *
 * Copyright (C) 2015-2017 Texas Instruments Incorporated - https://www.ti.com/
 */

#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_graph.h>
#include <linux/platform_device.h>

#include "dss.h"
#include "omapdss.h"

struct dispc_device *dispc_get_dispc(struct dss_device *dss)
{
        return dss->dispc;
}

/* -----------------------------------------------------------------------------
 * OMAP DSS Devices Handling
 */

static LIST_HEAD(omapdss_devices_list);
static DEFINE_MUTEX(omapdss_devices_lock);

void omapdss_device_register(struct omap_dss_device *dssdev)
{
        mutex_lock(&omapdss_devices_lock);
        list_add_tail(&dssdev->list, &omapdss_devices_list);
        mutex_unlock(&omapdss_devices_lock);
}

void omapdss_device_unregister(struct omap_dss_device *dssdev)
{
        mutex_lock(&omapdss_devices_lock);
        list_del(&dssdev->list);
        mutex_unlock(&omapdss_devices_lock);
}

static bool omapdss_device_is_registered(struct device_node *node)
{
        struct omap_dss_device *dssdev;
        bool found = false;

        mutex_lock(&omapdss_devices_lock);

        list_for_each_entry(dssdev, &omapdss_devices_list, list) {
                if (dssdev->dev->of_node == node) {
                        found = true;
                        break;
                }
        }

        mutex_unlock(&omapdss_devices_lock);
        return found;
}

struct omap_dss_device *omapdss_device_get(struct omap_dss_device *dssdev)
{
        if (get_device(dssdev->dev) == NULL)
                return NULL;

        return dssdev;
}

void omapdss_device_put(struct omap_dss_device *dssdev)
{
        put_device(dssdev->dev);
}

struct omap_dss_device *omapdss_find_device_by_node(struct device_node *node)
{
        struct omap_dss_device *dssdev;

        list_for_each_entry(dssdev, &omapdss_devices_list, list) {
                if (dssdev->dev->of_node == node)
                        return omapdss_device_get(dssdev);
        }

        return NULL;
}

/*
 * Search for the next output device starting at @from. Release the reference to
 * the @from device, and acquire a reference to the returned device if found.
 */
struct omap_dss_device *omapdss_device_next_output(struct omap_dss_device *from)
{
        struct omap_dss_device *dssdev;
        struct list_head *list;

        mutex_lock(&omapdss_devices_lock);

        if (list_empty(&omapdss_devices_list)) {
                dssdev = NULL;
                goto done;
        }

        /*
         * Start from the from entry if given or from omapdss_devices_list
         * otherwise.
         */
        list = from ? &from->list : &omapdss_devices_list;

        list_for_each_entry(dssdev, list, list) {
                /*
                 * Stop if we reach the omapdss_devices_list, that's the end of
                 * the list.
                 */
                if (&dssdev->list == &omapdss_devices_list) {
                        dssdev = NULL;
                        goto done;
                }

                if (dssdev->id && dssdev->bridge)
                        goto done;
        }

        dssdev = NULL;

done:
        if (from)
                omapdss_device_put(from);
        if (dssdev)
                omapdss_device_get(dssdev);

        mutex_unlock(&omapdss_devices_lock);
        return dssdev;
}

static bool omapdss_device_is_connected(struct omap_dss_device *dssdev)
{
        return dssdev->dss;
}

int omapdss_device_connect(struct dss_device *dss,
                           struct omap_dss_device *src,
                           struct omap_dss_device *dst)
{
        dev_dbg(&dss->pdev->dev, "connect(%s, %s)\n",
                src ? dev_name(src->dev) : "NULL",
                dst ? dev_name(dst->dev) : "NULL");

        if (!dst) {
                /*
                 * The destination is NULL when the source is connected to a
                 * bridge instead of a DSS device. Stop here, we will attach
                 * the bridge later when we will have a DRM encoder.
                 */
                return src && src->bridge ? 0 : -EINVAL;
        }

        if (omapdss_device_is_connected(dst))
                return -EBUSY;

        dst->dss = dss;

        return 0;
}

void omapdss_device_disconnect(struct omap_dss_device *src,
                               struct omap_dss_device *dst)
{
        struct dss_device *dss = src ? src->dss : dst->dss;

        dev_dbg(&dss->pdev->dev, "disconnect(%s, %s)\n",
                src ? dev_name(src->dev) : "NULL",
                dst ? dev_name(dst->dev) : "NULL");

        if (!dst) {
                WARN_ON(!src->bridge);
                return;
        }

        if (!dst->id && !omapdss_device_is_connected(dst)) {
                WARN_ON(1);
                return;
        }

        dst->dss = NULL;
}

/* -----------------------------------------------------------------------------
 * Components Handling
 */

static struct list_head omapdss_comp_list;

struct omapdss_comp_node {
        struct list_head list;
        struct device_node *node;
        bool dss_core_component;
        const char *compat;
};

static bool omapdss_list_contains(const struct device_node *node)
{
        struct omapdss_comp_node *comp;

        list_for_each_entry(comp, &omapdss_comp_list, list) {
                if (comp->node == node)
                        return true;
        }

        return false;
}

static void omapdss_walk_device(struct device *dev, struct device_node *node,
                                bool dss_core)
{
        struct omapdss_comp_node *comp;
        struct device_node *n;
        const char *compat;
        int ret;

        ret = of_property_read_string(node, "compatible", &compat);
        if (ret < 0)
                return;

        comp = devm_kzalloc(dev, sizeof(*comp), GFP_KERNEL);
        if (comp) {
                comp->node = node;
                comp->dss_core_component = dss_core;
                comp->compat = compat;
                list_add(&comp->list, &omapdss_comp_list);
        }

        /*
         * of_graph_get_remote_port_parent() prints an error if there is no
         * port/ports node. To avoid that, check first that there's the node.
         */
        n = of_get_child_by_name(node, "ports");
        if (!n)
                n = of_get_child_by_name(node, "port");
        if (!n)
                return;

        of_node_put(n);

        n = NULL;
        while ((n = of_graph_get_next_endpoint(node, n)) != NULL) {
                struct device_node *pn = of_graph_get_remote_port_parent(n);

                if (!pn)
                        continue;

                if (!of_device_is_available(pn) || omapdss_list_contains(pn)) {
                        of_node_put(pn);
                        continue;
                }

                omapdss_walk_device(dev, pn, false);
        }
}

void omapdss_gather_components(struct device *dev)
{
        struct device_node *child;

        INIT_LIST_HEAD(&omapdss_comp_list);

        omapdss_walk_device(dev, dev->of_node, true);

        for_each_available_child_of_node(dev->of_node, child)
                omapdss_walk_device(dev, child, true);
}

static bool omapdss_component_is_loaded(struct omapdss_comp_node *comp)
{
        if (comp->dss_core_component)
                return true;
        if (!strstarts(comp->compat, "omapdss,"))
                return true;
        if (omapdss_device_is_registered(comp->node))
                return true;

        return false;
}

bool omapdss_stack_is_ready(void)
{
        struct omapdss_comp_node *comp;

        list_for_each_entry(comp, &omapdss_comp_list, list) {
                if (!omapdss_component_is_loaded(comp))
                        return false;
        }

        return true;
}