/*
 * Media driver for Freescale i.MX5/6 SOC
 *
 * Open Firmware parsing.
 *
 * Copyright (c) 2016 Mentor Graphics Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */
#include <linux/of_platform.h>
#include <media/v4l2-ctrls.h>
#include <media/v4l2-device.h>
#include <media/v4l2-fwnode.h>
#include <media/v4l2-subdev.h>
#include <media/videobuf2-dma-contig.h>
#include <linux/of_graph.h>
#include <video/imx-ipu-v3.h>
#include "imx-media.h"

static int of_get_port_count(const struct device_node *np)
{
        struct device_node *ports, *child;
        int num = 0;

        /* check if this node has a ports subnode */
        ports = of_get_child_by_name(np, "ports");
        if (ports)
                np = ports;

        for_each_child_of_node(np, child)
                if (of_node_cmp(child->name, "port") == 0)
                        num++;

        of_node_put(ports);
        return num;
}

/*
 * find the remote device node given local endpoint node
 */
static bool of_get_remote(struct device_node *epnode,
                          struct device_node **remote_node)
{
        struct device_node *rp, *rpp;
        struct device_node *remote;
        bool is_csi_port;

        rp = of_graph_get_remote_port(epnode);
        rpp = of_graph_get_remote_port_parent(epnode);

        if (of_device_is_compatible(rpp, "fsl,imx6q-ipu")) {
                /* the remote is one of the CSI ports */
                remote = rp;
                of_node_put(rpp);
                is_csi_port = true;
        } else {
                remote = rpp;
                of_node_put(rp);
                is_csi_port = false;
        }

        if (!of_device_is_available(remote)) {
                of_node_put(remote);
                *remote_node = NULL;
        } else {
                *remote_node = remote;
        }

        return is_csi_port;
}

static int
of_parse_subdev(struct imx_media_dev *imxmd, struct device_node *sd_np,
                bool is_csi_port)
{
        int i, num_ports, ret;

        if (!of_device_is_available(sd_np)) {
                dev_dbg(imxmd->md.dev, "%s: %s not enabled\n", __func__,
                        sd_np->name);
                /* unavailable is not an error */
                return 0;
        }

        /* register this subdev with async notifier */
        ret = imx_media_add_async_subdev(imxmd, of_fwnode_handle(sd_np),
                                         NULL);
        if (ret) {
                if (ret == -EEXIST) {
                        /* already added, everything is fine */
                        return 0;
                }

                /* other error, can't continue */
                return ret;
        }

        /*
         * the ipu-csi has one sink port. The source pads are not
         * represented in the device tree by port nodes, but are
         * described by the internal pads and links later.
         */
        num_ports = is_csi_port ? 1 : of_get_port_count(sd_np);

        for (i = 0; i < num_ports; i++) {
                struct device_node *epnode = NULL, *port, *remote_np;

                port = is_csi_port ? sd_np : of_graph_get_port_by_id(sd_np, i);
                if (!port)
                        continue;

                for_each_child_of_node(port, epnode) {
                        bool remote_is_csi;

                        remote_is_csi = of_get_remote(epnode, &remote_np);
                        if (!remote_np)
                                continue;

                        ret = of_parse_subdev(imxmd, remote_np, remote_is_csi);
                        of_node_put(remote_np);
                        if (ret)
                                break;
                }

                if (port != sd_np)
                        of_node_put(port);
                if (ret) {
                        of_node_put(epnode);
                        break;
                }
        }

        return ret;
}

int imx_media_add_of_subdevs(struct imx_media_dev *imxmd,
                             struct device_node *np)
{
        struct device_node *csi_np;
        int i, ret;

        for (i = 0; ; i++) {
                csi_np = of_parse_phandle(np, "ports", i);
                if (!csi_np)
                        break;

                ret = of_parse_subdev(imxmd, csi_np, true);
                of_node_put(csi_np);
                if (ret)
                        return ret;
        }

        return 0;
}

/*
 * Create a single media link to/from sd using a fwnode link.
 *
 * NOTE: this function assumes an OF port node is equivalent to
 * a media pad (port id equal to media pad index), and that an
 * OF endpoint node is equivalent to a media link.
 */
static int create_of_link(struct imx_media_dev *imxmd,
                          struct v4l2_subdev *sd,
                          struct v4l2_fwnode_link *link)
{
        struct v4l2_subdev *remote, *src, *sink;
        int src_pad, sink_pad;

        if (link->local_port >= sd->entity.num_pads)
                return -EINVAL;

        remote = imx_media_find_subdev_by_fwnode(imxmd, link->remote_node);
        if (!remote)
                return 0;

        if (sd->entity.pads[link->local_port].flags & MEDIA_PAD_FL_SINK) {
                src = remote;
                src_pad = link->remote_port;
                sink = sd;
                sink_pad = link->local_port;
        } else {
                src = sd;
                src_pad = link->local_port;
                sink = remote;
                sink_pad = link->remote_port;
        }

        /* make sure link doesn't already exist before creating */
        if (media_entity_find_link(&src->entity.pads[src_pad],
                                   &sink->entity.pads[sink_pad]))
                return 0;

        v4l2_info(sd->v4l2_dev, "%s:%d -> %s:%d\n",
                  src->name, src_pad, sink->name, sink_pad);

        return media_create_pad_link(&src->entity, src_pad,
                                     &sink->entity, sink_pad, 0);
}

/*
 * Create media links to/from sd using its device-tree endpoints.
 */
int imx_media_create_of_links(struct imx_media_dev *imxmd,
                              struct v4l2_subdev *sd)
{
        struct v4l2_fwnode_link link;
        struct device_node *ep;
        int ret;

        for_each_endpoint_of_node(sd->dev->of_node, ep) {
                ret = v4l2_fwnode_parse_link(of_fwnode_handle(ep), &link);
                if (ret)
                        continue;

                ret = create_of_link(imxmd, sd, &link);
                v4l2_fwnode_put_link(&link);
                if (ret)
                        return ret;
        }

        return 0;
}

/*
 * Create media links to the given CSI subdevice's sink pads,
 * using its device-tree endpoints.
 */
int imx_media_create_csi_of_links(struct imx_media_dev *imxmd,
                                  struct v4l2_subdev *csi)
{
        struct device_node *csi_np = csi->dev->of_node;
        struct fwnode_handle *fwnode, *csi_ep;
        struct v4l2_fwnode_link link;
        struct device_node *ep;
        int ret;

        link.local_node = of_fwnode_handle(csi_np);
        link.local_port = CSI_SINK_PAD;

        for_each_child_of_node(csi_np, ep) {
                csi_ep = of_fwnode_handle(ep);

                fwnode = fwnode_graph_get_remote_endpoint(csi_ep);
                if (!fwnode)
                        continue;

                fwnode = fwnode_get_parent(fwnode);
                fwnode_property_read_u32(fwnode, "reg", &link.remote_port);
                fwnode = fwnode_get_next_parent(fwnode);
                if (is_of_node(fwnode) &&
                    of_node_cmp(to_of_node(fwnode)->name, "ports") == 0)
                        fwnode = fwnode_get_next_parent(fwnode);
                link.remote_node = fwnode;

                ret = create_of_link(imxmd, csi, &link);
                fwnode_handle_put(link.remote_node);
                if (ret)
                        return ret;
        }

        return 0;
}