/*
 * vsp1_video.c  --  R-Car VSP1 Video Node
 *
 * Copyright (C) 2013-2015 Renesas Electronics Corporation
 *
 * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
 *
 * 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/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/v4l2-mediabus.h>
#include <linux/videodev2.h>
#include <linux/wait.h>

#include <media/media-entity.h>
#include <media/v4l2-dev.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-subdev.h>
#include <media/videobuf2-v4l2.h>
#include <media/videobuf2-dma-contig.h>

#include "vsp1.h"
#include "vsp1_bru.h"
#include "vsp1_entity.h"
#include "vsp1_pipe.h"
#include "vsp1_rwpf.h"
#include "vsp1_uds.h"
#include "vsp1_video.h"

#define VSP1_VIDEO_DEF_FORMAT           V4L2_PIX_FMT_YUYV
#define VSP1_VIDEO_DEF_WIDTH            1024
#define VSP1_VIDEO_DEF_HEIGHT           768

#define VSP1_VIDEO_MIN_WIDTH            2U
#define VSP1_VIDEO_MAX_WIDTH            8190U
#define VSP1_VIDEO_MIN_HEIGHT           2U
#define VSP1_VIDEO_MAX_HEIGHT           8190U

/* -----------------------------------------------------------------------------
 * Helper functions
 */

static struct v4l2_subdev *
vsp1_video_remote_subdev(struct media_pad *local, u32 *pad)
{
        struct media_pad *remote;

        remote = media_entity_remote_pad(local);
        if (!remote || !is_media_entity_v4l2_subdev(remote->entity))
                return NULL;

        if (pad)
                *pad = remote->index;

        return media_entity_to_v4l2_subdev(remote->entity);
}

static int vsp1_video_verify_format(struct vsp1_video *video)
{
        struct v4l2_subdev_format fmt;
        struct v4l2_subdev *subdev;
        int ret;

        subdev = vsp1_video_remote_subdev(&video->pad, &fmt.pad);
        if (subdev == NULL)
                return -EINVAL;

        fmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
        ret = v4l2_subdev_call(subdev, pad, get_fmt, NULL, &fmt);
        if (ret < 0)
                return ret == -ENOIOCTLCMD ? -EINVAL : ret;

        if (video->rwpf->fmtinfo->mbus != fmt.format.code ||
            video->rwpf->format.height != fmt.format.height ||
            video->rwpf->format.width != fmt.format.width)
                return -EINVAL;

        return 0;
}

static int __vsp1_video_try_format(struct vsp1_video *video,
                                   struct v4l2_pix_format_mplane *pix,
                                   const struct vsp1_format_info **fmtinfo)
{
        static const u32 xrgb_formats[][2] = {
                { V4L2_PIX_FMT_RGB444, V4L2_PIX_FMT_XRGB444 },
                { V4L2_PIX_FMT_RGB555, V4L2_PIX_FMT_XRGB555 },
                { V4L2_PIX_FMT_BGR32, V4L2_PIX_FMT_XBGR32 },
                { V4L2_PIX_FMT_RGB32, V4L2_PIX_FMT_XRGB32 },
        };

        const struct vsp1_format_info *info;
        unsigned int width = pix->width;
        unsigned int height = pix->height;
        unsigned int i;

        /* Backward compatibility: replace deprecated RGB formats by their XRGB
         * equivalent. This selects the format older userspace applications want
         * while still exposing the new format.
         */
        for (i = 0; i < ARRAY_SIZE(xrgb_formats); ++i) {
                if (xrgb_formats[i][0] == pix->pixelformat) {
                        pix->pixelformat = xrgb_formats[i][1];
                        break;
                }
        }

        /* Retrieve format information and select the default format if the
         * requested format isn't supported.
         */
        info = vsp1_get_format_info(pix->pixelformat);
        if (info == NULL)
                info = vsp1_get_format_info(VSP1_VIDEO_DEF_FORMAT);

        pix->pixelformat = info->fourcc;
        pix->colorspace = V4L2_COLORSPACE_SRGB;
        pix->field = V4L2_FIELD_NONE;
        memset(pix->reserved, 0, sizeof(pix->reserved));

        /* Align the width and height for YUV 4:2:2 and 4:2:0 formats. */
        width = round_down(width, info->hsub);
        height = round_down(height, info->vsub);

        /* Clamp the width and height. */
        pix->width = clamp(width, VSP1_VIDEO_MIN_WIDTH, VSP1_VIDEO_MAX_WIDTH);
        pix->height = clamp(height, VSP1_VIDEO_MIN_HEIGHT,
                            VSP1_VIDEO_MAX_HEIGHT);

        /* Compute and clamp the stride and image size. While not documented in
         * the datasheet, strides not aligned to a multiple of 128 bytes result
         * in image corruption.
         */
        for (i = 0; i < min(info->planes, 2U); ++i) {
                unsigned int hsub = i > 0 ? info->hsub : 1;
                unsigned int vsub = i > 0 ? info->vsub : 1;
                unsigned int align = 128;
                unsigned int bpl;

                bpl = clamp_t(unsigned int, pix->plane_fmt[i].bytesperline,
                              pix->width / hsub * info->bpp[i] / 8,
                              round_down(65535U, align));

                pix->plane_fmt[i].bytesperline = round_up(bpl, align);
                pix->plane_fmt[i].sizeimage = pix->plane_fmt[i].bytesperline
                                            * pix->height / vsub;
        }

        if (info->planes == 3) {
                /* The second and third planes must have the same stride. */
                pix->plane_fmt[2].bytesperline = pix->plane_fmt[1].bytesperline;
                pix->plane_fmt[2].sizeimage = pix->plane_fmt[1].sizeimage;
        }

        pix->num_planes = info->planes;

        if (fmtinfo)
                *fmtinfo = info;

        return 0;
}

/* -----------------------------------------------------------------------------
 * Pipeline Management
 */

static int vsp1_video_pipeline_validate_branch(struct vsp1_pipeline *pipe,
                                               struct vsp1_rwpf *input,
                                               struct vsp1_rwpf *output)
{
        struct vsp1_entity *entity;
        struct media_entity_enum ent_enum;
        struct media_pad *pad;
        int rval;
        bool bru_found = false;

        input->location.left = 0;
        input->location.top = 0;

        rval = media_entity_enum_init(
                &ent_enum, input->entity.pads[RWPF_PAD_SOURCE].graph_obj.mdev);
        if (rval)
                return rval;

        pad = media_entity_remote_pad(&input->entity.pads[RWPF_PAD_SOURCE]);

        while (1) {
                if (pad == NULL) {
                        rval = -EPIPE;
                        goto out;
                }

                /* We've reached a video node, that shouldn't have happened. */
                if (!is_media_entity_v4l2_subdev(pad->entity)) {
                        rval = -EPIPE;
                        goto out;
                }

                entity = to_vsp1_entity(
                        media_entity_to_v4l2_subdev(pad->entity));

                /* A BRU is present in the pipeline, store the compose rectangle
                 * location in the input RPF for use when configuring the RPF.
                 */
                if (entity->type == VSP1_ENTITY_BRU) {
                        struct vsp1_bru *bru = to_bru(&entity->subdev);
                        struct v4l2_rect *rect =
                                &bru->inputs[pad->index].compose;

                        bru->inputs[pad->index].rpf = input;

                        input->location.left = rect->left;
                        input->location.top = rect->top;

                        bru_found = true;
                }

                /* We've reached the WPF, we're done. */
                if (entity->type == VSP1_ENTITY_WPF)
                        break;

                /* Ensure the branch has no loop. */
                if (media_entity_enum_test_and_set(&ent_enum,
                                                   &entity->subdev.entity)) {
                        rval = -EPIPE;
                        goto out;
                }

                /* UDS can't be chained. */
                if (entity->type == VSP1_ENTITY_UDS) {
                        if (pipe->uds) {
                                rval = -EPIPE;
                                goto out;
                        }

                        pipe->uds = entity;
                        pipe->uds_input = bru_found ? pipe->bru
                                        : &input->entity;
                }

                /* Follow the source link. The link setup operations ensure
                 * that the output fan-out can't be more than one, there is thus
                 * no need to verify here that only a single source link is
                 * activated.
                 */
                pad = &entity->pads[entity->source_pad];
                pad = media_entity_remote_pad(pad);
        }

        /* The last entity must be the output WPF. */
        if (entity != &output->entity)
                rval = -EPIPE;

out:
        media_entity_enum_cleanup(&ent_enum);

        return rval;
}

static int vsp1_video_pipeline_validate(struct vsp1_pipeline *pipe,
                                        struct vsp1_video *video)
{
        struct media_entity_graph graph;
        struct media_entity *entity = &video->video.entity;
        struct media_device *mdev = entity->graph_obj.mdev;
        unsigned int i;
        int ret;

        mutex_lock(&mdev->graph_mutex);

        /* Walk the graph to locate the entities and video nodes. */
        ret = media_entity_graph_walk_init(&graph, mdev);
        if (ret) {
                mutex_unlock(&mdev->graph_mutex);
                return ret;
        }

        media_entity_graph_walk_start(&graph, entity);

        while ((entity = media_entity_graph_walk_next(&graph))) {
                struct v4l2_subdev *subdev;
                struct vsp1_rwpf *rwpf;
                struct vsp1_entity *e;

                if (!is_media_entity_v4l2_subdev(entity))
                        continue;

                subdev = media_entity_to_v4l2_subdev(entity);
                e = to_vsp1_entity(subdev);
                list_add_tail(&e->list_pipe, &pipe->entities);

                if (e->type == VSP1_ENTITY_RPF) {
                        rwpf = to_rwpf(subdev);
                        pipe->inputs[rwpf->entity.index] = rwpf;
                        rwpf->video->pipe_index = ++pipe->num_inputs;
                } else if (e->type == VSP1_ENTITY_WPF) {
                        rwpf = to_rwpf(subdev);
                        pipe->output = rwpf;
                        rwpf->video->pipe_index = 0;
                } else if (e->type == VSP1_ENTITY_LIF) {
                        pipe->lif = e;
                } else if (e->type == VSP1_ENTITY_BRU) {
                        pipe->bru = e;
                }
        }

        mutex_unlock(&mdev->graph_mutex);

        media_entity_graph_walk_cleanup(&graph);

        /* We need one output and at least one input. */
        if (pipe->num_inputs == 0 || !pipe->output) {
                ret = -EPIPE;
                goto error;
        }

        /* Follow links downstream for each input and make sure the graph
         * contains no loop and that all branches end at the output WPF.
         */
        for (i = 0; i < video->vsp1->info->rpf_count; ++i) {
                if (!pipe->inputs[i])
                        continue;

                ret = vsp1_video_pipeline_validate_branch(pipe, pipe->inputs[i],
                                                          pipe->output);
                if (ret < 0)
                        goto error;
        }

        return 0;

error:
        vsp1_pipeline_reset(pipe);
        return ret;
}

static int vsp1_video_pipeline_init(struct vsp1_pipeline *pipe,
                                    struct vsp1_video *video)
{
        int ret;

        mutex_lock(&pipe->lock);

        /* If we're the first user validate and initialize the pipeline. */
        if (pipe->use_count == 0) {
                ret = vsp1_video_pipeline_validate(pipe, video);
                if (ret < 0)
                        goto done;
        }

        pipe->use_count++;
        ret = 0;

done:
        mutex_unlock(&pipe->lock);
        return ret;
}

static void vsp1_video_pipeline_cleanup(struct vsp1_pipeline *pipe)
{
        mutex_lock(&pipe->lock);

        /* If we're the last user clean up the pipeline. */
        if (--pipe->use_count == 0)
                vsp1_pipeline_reset(pipe);

        mutex_unlock(&pipe->lock);
}

/*
 * vsp1_video_complete_buffer - Complete the current buffer
 * @video: the video node
 *
 * This function completes the current buffer by filling its sequence number,
 * time stamp and payload size, and hands it back to the videobuf core.
 *
 * When operating in DU output mode (deep pipeline to the DU through the LIF),
 * the VSP1 needs to constantly supply frames to the display. In that case, if
 * no other buffer is queued, reuse the one that has just been processed instead
 * of handing it back to the videobuf core.
 *
 * Return the next queued buffer or NULL if the queue is empty.
 */
static struct vsp1_vb2_buffer *
vsp1_video_complete_buffer(struct vsp1_video *video)
{
        struct vsp1_pipeline *pipe = to_vsp1_pipeline(&video->video.entity);
        struct vsp1_vb2_buffer *next = NULL;
        struct vsp1_vb2_buffer *done;
        unsigned long flags;
        unsigned int i;

        spin_lock_irqsave(&video->irqlock, flags);

        if (list_empty(&video->irqqueue)) {
                spin_unlock_irqrestore(&video->irqlock, flags);
                return NULL;
        }

        done = list_first_entry(&video->irqqueue,
                                struct vsp1_vb2_buffer, queue);

        /* In DU output mode reuse the buffer if the list is singular. */
        if (pipe->lif && list_is_singular(&video->irqqueue)) {
                spin_unlock_irqrestore(&video->irqlock, flags);
                return done;
        }

        list_del(&done->queue);

        if (!list_empty(&video->irqqueue))
                next = list_first_entry(&video->irqqueue,
                                        struct vsp1_vb2_buffer, queue);

        spin_unlock_irqrestore(&video->irqlock, flags);

        done->buf.sequence = video->sequence++;
        done->buf.vb2_buf.timestamp = ktime_get_ns();
        for (i = 0; i < done->buf.vb2_buf.num_planes; ++i)
                vb2_set_plane_payload(&done->buf.vb2_buf, i,
                                      done->mem.length[i]);
        vb2_buffer_done(&done->buf.vb2_buf, VB2_BUF_STATE_DONE);

        return next;
}

static void vsp1_video_frame_end(struct vsp1_pipeline *pipe,
                                 struct vsp1_rwpf *rwpf)
{
        struct vsp1_video *video = rwpf->video;
        struct vsp1_vb2_buffer *buf;
        unsigned long flags;

        buf = vsp1_video_complete_buffer(video);
        if (buf == NULL)
                return;

        spin_lock_irqsave(&pipe->irqlock, flags);

        video->rwpf->ops->set_memory(video->rwpf, &buf->mem);
        pipe->buffers_ready |= 1 << video->pipe_index;

        spin_unlock_irqrestore(&pipe->irqlock, flags);
}

static void vsp1_video_pipeline_frame_end(struct vsp1_pipeline *pipe)
{
        struct vsp1_device *vsp1 = pipe->output->entity.vsp1;
        unsigned int i;

        /* Complete buffers on all video nodes. */
        for (i = 0; i < vsp1->info->rpf_count; ++i) {
                if (!pipe->inputs[i])
                        continue;

                vsp1_video_frame_end(pipe, pipe->inputs[i]);
        }

        if (!pipe->lif)
                vsp1_video_frame_end(pipe, pipe->output);
}

/* -----------------------------------------------------------------------------
 * videobuf2 Queue Operations
 */

static int
vsp1_video_queue_setup(struct vb2_queue *vq,
                     unsigned int *nbuffers, unsigned int *nplanes,
                     unsigned int sizes[], void *alloc_ctxs[])
{
        struct vsp1_video *video = vb2_get_drv_priv(vq);
        const struct v4l2_pix_format_mplane *format = &video->rwpf->format;
        unsigned int i;

        if (*nplanes) {
                if (*nplanes != format->num_planes)
                        return -EINVAL;

                for (i = 0; i < *nplanes; i++) {
                        if (sizes[i] < format->plane_fmt[i].sizeimage)
                                return -EINVAL;
                        alloc_ctxs[i] = video->alloc_ctx;
                }
                return 0;
        }

        *nplanes = format->num_planes;

        for (i = 0; i < format->num_planes; ++i) {
                sizes[i] = format->plane_fmt[i].sizeimage;
                alloc_ctxs[i] = video->alloc_ctx;
        }

        return 0;
}

static int vsp1_video_buffer_prepare(struct vb2_buffer *vb)
{
        struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
        struct vsp1_video *video = vb2_get_drv_priv(vb->vb2_queue);
        struct vsp1_vb2_buffer *buf = to_vsp1_vb2_buffer(vbuf);
        const struct v4l2_pix_format_mplane *format = &video->rwpf->format;
        unsigned int i;

        if (vb->num_planes < format->num_planes)
                return -EINVAL;

        buf->mem.num_planes = vb->num_planes;

        for (i = 0; i < vb->num_planes; ++i) {
                buf->mem.addr[i] = vb2_dma_contig_plane_dma_addr(vb, i);
                buf->mem.length[i] = vb2_plane_size(vb, i);

                if (buf->mem.length[i] < format->plane_fmt[i].sizeimage)
                        return -EINVAL;
        }

        return 0;
}

static void vsp1_video_buffer_queue(struct vb2_buffer *vb)
{
        struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
        struct vsp1_video *video = vb2_get_drv_priv(vb->vb2_queue);
        struct vsp1_pipeline *pipe = to_vsp1_pipeline(&video->video.entity);
        struct vsp1_vb2_buffer *buf = to_vsp1_vb2_buffer(vbuf);
        unsigned long flags;
        bool empty;

        spin_lock_irqsave(&video->irqlock, flags);
        empty = list_empty(&video->irqqueue);
        list_add_tail(&buf->queue, &video->irqqueue);
        spin_unlock_irqrestore(&video->irqlock, flags);

        if (!empty)
                return;

        spin_lock_irqsave(&pipe->irqlock, flags);

        video->rwpf->ops->set_memory(video->rwpf, &buf->mem);
        pipe->buffers_ready |= 1 << video->pipe_index;

        if (vb2_is_streaming(&video->queue) &&
            vsp1_pipeline_ready(pipe))
                vsp1_pipeline_run(pipe);

        spin_unlock_irqrestore(&pipe->irqlock, flags);
}

static int vsp1_video_start_streaming(struct vb2_queue *vq, unsigned int count)
{
        struct vsp1_video *video = vb2_get_drv_priv(vq);
        struct vsp1_pipeline *pipe = to_vsp1_pipeline(&video->video.entity);
        struct vsp1_entity *entity;
        unsigned long flags;
        int ret;

        mutex_lock(&pipe->lock);
        if (pipe->stream_count == pipe->num_inputs) {
                if (pipe->uds) {
                        struct vsp1_uds *uds = to_uds(&pipe->uds->subdev);

                        /* If a BRU is present in the pipeline before the UDS,
                         * the alpha component doesn't need to be scaled as the
                         * BRU output alpha value is fixed to 255. Otherwise we
                         * need to scale the alpha component only when available
                         * at the input RPF.
                         */
                        if (pipe->uds_input->type == VSP1_ENTITY_BRU) {
                                uds->scale_alpha = false;
                        } else {
                                struct vsp1_rwpf *rpf =
                                        to_rwpf(&pipe->uds_input->subdev);

                                uds->scale_alpha = rpf->fmtinfo->alpha;
                        }
                }

                list_for_each_entry(entity, &pipe->entities, list_pipe) {
                        vsp1_entity_route_setup(entity);

                        ret = v4l2_subdev_call(&entity->subdev, video,
                                               s_stream, 1);
                        if (ret < 0) {
                                mutex_unlock(&pipe->lock);
                                return ret;
                        }
                }
        }

        pipe->stream_count++;
        mutex_unlock(&pipe->lock);

        spin_lock_irqsave(&pipe->irqlock, flags);
        if (vsp1_pipeline_ready(pipe))
                vsp1_pipeline_run(pipe);
        spin_unlock_irqrestore(&pipe->irqlock, flags);

        return 0;
}

static void vsp1_video_stop_streaming(struct vb2_queue *vq)
{
        struct vsp1_video *video = vb2_get_drv_priv(vq);
        struct vsp1_pipeline *pipe = to_vsp1_pipeline(&video->video.entity);
        struct vsp1_vb2_buffer *buffer;
        unsigned long flags;
        int ret;

        mutex_lock(&pipe->lock);
        if (--pipe->stream_count == 0) {
                /* Stop the pipeline. */
                ret = vsp1_pipeline_stop(pipe);
                if (ret == -ETIMEDOUT)
                        dev_err(video->vsp1->dev, "pipeline stop timeout\n");
        }
        mutex_unlock(&pipe->lock);

        vsp1_video_pipeline_cleanup(pipe);
        media_entity_pipeline_stop(&video->video.entity);

        /* Remove all buffers from the IRQ queue. */
        spin_lock_irqsave(&video->irqlock, flags);
        list_for_each_entry(buffer, &video->irqqueue, queue)
                vb2_buffer_done(&buffer->buf.vb2_buf, VB2_BUF_STATE_ERROR);
        INIT_LIST_HEAD(&video->irqqueue);
        spin_unlock_irqrestore(&video->irqlock, flags);
}

static struct vb2_ops vsp1_video_queue_qops = {
        .queue_setup = vsp1_video_queue_setup,
        .buf_prepare = vsp1_video_buffer_prepare,
        .buf_queue = vsp1_video_buffer_queue,
        .wait_prepare = vb2_ops_wait_prepare,
        .wait_finish = vb2_ops_wait_finish,
        .start_streaming = vsp1_video_start_streaming,
        .stop_streaming = vsp1_video_stop_streaming,
};

/* -----------------------------------------------------------------------------
 * V4L2 ioctls
 */

static int
vsp1_video_querycap(struct file *file, void *fh, struct v4l2_capability *cap)
{
        struct v4l2_fh *vfh = file->private_data;
        struct vsp1_video *video = to_vsp1_video(vfh->vdev);

        cap->capabilities = V4L2_CAP_DEVICE_CAPS | V4L2_CAP_STREAMING
                          | V4L2_CAP_VIDEO_CAPTURE_MPLANE
                          | V4L2_CAP_VIDEO_OUTPUT_MPLANE;

        if (video->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE)
                cap->device_caps = V4L2_CAP_VIDEO_CAPTURE_MPLANE
                                 | V4L2_CAP_STREAMING;
        else
                cap->device_caps = V4L2_CAP_VIDEO_OUTPUT_MPLANE
                                 | V4L2_CAP_STREAMING;

        strlcpy(cap->driver, "vsp1", sizeof(cap->driver));
        strlcpy(cap->card, video->video.name, sizeof(cap->card));
        snprintf(cap->bus_info, sizeof(cap->bus_info), "platform:%s",
                 dev_name(video->vsp1->dev));

        return 0;
}

static int
vsp1_video_get_format(struct file *file, void *fh, struct v4l2_format *format)
{
        struct v4l2_fh *vfh = file->private_data;
        struct vsp1_video *video = to_vsp1_video(vfh->vdev);

        if (format->type != video->queue.type)
                return -EINVAL;

        mutex_lock(&video->lock);
        format->fmt.pix_mp = video->rwpf->format;
        mutex_unlock(&video->lock);

        return 0;
}

static int
vsp1_video_try_format(struct file *file, void *fh, struct v4l2_format *format)
{
        struct v4l2_fh *vfh = file->private_data;
        struct vsp1_video *video = to_vsp1_video(vfh->vdev);

        if (format->type != video->queue.type)
                return -EINVAL;

        return __vsp1_video_try_format(video, &format->fmt.pix_mp, NULL);
}

static int
vsp1_video_set_format(struct file *file, void *fh, struct v4l2_format *format)
{
        struct v4l2_fh *vfh = file->private_data;
        struct vsp1_video *video = to_vsp1_video(vfh->vdev);
        const struct vsp1_format_info *info;
        int ret;

        if (format->type != video->queue.type)
                return -EINVAL;

        ret = __vsp1_video_try_format(video, &format->fmt.pix_mp, &info);
        if (ret < 0)
                return ret;

        mutex_lock(&video->lock);

        if (vb2_is_busy(&video->queue)) {
                ret = -EBUSY;
                goto done;
        }

        video->rwpf->format = format->fmt.pix_mp;
        video->rwpf->fmtinfo = info;

done:
        mutex_unlock(&video->lock);
        return ret;
}

static int
vsp1_video_streamon(struct file *file, void *fh, enum v4l2_buf_type type)
{
        struct v4l2_fh *vfh = file->private_data;
        struct vsp1_video *video = to_vsp1_video(vfh->vdev);
        struct vsp1_pipeline *pipe;
        int ret;

        if (video->queue.owner && video->queue.owner != file->private_data)
                return -EBUSY;

        video->sequence = 0;

        /* Start streaming on the pipeline. No link touching an entity in the
         * pipeline can be activated or deactivated once streaming is started.
         *
         * Use the VSP1 pipeline object embedded in the first video object that
         * starts streaming.
         */
        pipe = video->video.entity.pipe
             ? to_vsp1_pipeline(&video->video.entity) : &video->pipe;

        ret = media_entity_pipeline_start(&video->video.entity, &pipe->pipe);
        if (ret < 0)
                return ret;

        /* Verify that the configured format matches the output of the connected
         * subdev.
         */
        ret = vsp1_video_verify_format(video);
        if (ret < 0)
                goto err_stop;

        ret = vsp1_video_pipeline_init(pipe, video);
        if (ret < 0)
                goto err_stop;

        /* Start the queue. */
        ret = vb2_streamon(&video->queue, type);
        if (ret < 0)
                goto err_cleanup;

        return 0;

err_cleanup:
        vsp1_video_pipeline_cleanup(pipe);
err_stop:
        media_entity_pipeline_stop(&video->video.entity);
        return ret;
}

static const struct v4l2_ioctl_ops vsp1_video_ioctl_ops = {
        .vidioc_querycap                = vsp1_video_querycap,
        .vidioc_g_fmt_vid_cap_mplane    = vsp1_video_get_format,
        .vidioc_s_fmt_vid_cap_mplane    = vsp1_video_set_format,
        .vidioc_try_fmt_vid_cap_mplane  = vsp1_video_try_format,
        .vidioc_g_fmt_vid_out_mplane    = vsp1_video_get_format,
        .vidioc_s_fmt_vid_out_mplane    = vsp1_video_set_format,
        .vidioc_try_fmt_vid_out_mplane  = vsp1_video_try_format,
        .vidioc_reqbufs                 = vb2_ioctl_reqbufs,
        .vidioc_querybuf                = vb2_ioctl_querybuf,
        .vidioc_qbuf                    = vb2_ioctl_qbuf,
        .vidioc_dqbuf                   = vb2_ioctl_dqbuf,
        .vidioc_create_bufs             = vb2_ioctl_create_bufs,
        .vidioc_prepare_buf             = vb2_ioctl_prepare_buf,
        .vidioc_streamon                = vsp1_video_streamon,
        .vidioc_streamoff               = vb2_ioctl_streamoff,
};

/* -----------------------------------------------------------------------------
 * V4L2 File Operations
 */

static int vsp1_video_open(struct file *file)
{
        struct vsp1_video *video = video_drvdata(file);
        struct v4l2_fh *vfh;
        int ret = 0;

        vfh = kzalloc(sizeof(*vfh), GFP_KERNEL);
        if (vfh == NULL)
                return -ENOMEM;

        v4l2_fh_init(vfh, &video->video);
        v4l2_fh_add(vfh);

        file->private_data = vfh;

        ret = vsp1_device_get(video->vsp1);
        if (ret < 0) {
                v4l2_fh_del(vfh);
                kfree(vfh);
        }

        return ret;
}

static int vsp1_video_release(struct file *file)
{
        struct vsp1_video *video = video_drvdata(file);
        struct v4l2_fh *vfh = file->private_data;

        mutex_lock(&video->lock);
        if (video->queue.owner == vfh) {
                vb2_queue_release(&video->queue);
                video->queue.owner = NULL;
        }
        mutex_unlock(&video->lock);

        vsp1_device_put(video->vsp1);

        v4l2_fh_release(file);

        file->private_data = NULL;

        return 0;
}

static struct v4l2_file_operations vsp1_video_fops = {
        .owner = THIS_MODULE,
        .unlocked_ioctl = video_ioctl2,
        .open = vsp1_video_open,
        .release = vsp1_video_release,
        .poll = vb2_fop_poll,
        .mmap = vb2_fop_mmap,
};

/* -----------------------------------------------------------------------------
 * Initialization and Cleanup
 */

struct vsp1_video *vsp1_video_create(struct vsp1_device *vsp1,
                                     struct vsp1_rwpf *rwpf)
{
        struct vsp1_video *video;
        const char *direction;
        int ret;

        video = devm_kzalloc(vsp1->dev, sizeof(*video), GFP_KERNEL);
        if (!video)
                return ERR_PTR(-ENOMEM);

        rwpf->video = video;

        video->vsp1 = vsp1;
        video->rwpf = rwpf;

        if (rwpf->entity.type == VSP1_ENTITY_RPF) {
                direction = "input";
                video->type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
                video->pad.flags = MEDIA_PAD_FL_SOURCE;
                video->video.vfl_dir = VFL_DIR_TX;
        } else {
                direction = "output";
                video->type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
                video->pad.flags = MEDIA_PAD_FL_SINK;
                video->video.vfl_dir = VFL_DIR_RX;
        }

        mutex_init(&video->lock);
        spin_lock_init(&video->irqlock);
        INIT_LIST_HEAD(&video->irqqueue);

        vsp1_pipeline_init(&video->pipe);
        video->pipe.frame_end = vsp1_video_pipeline_frame_end;

        /* Initialize the media entity... */
        ret = media_entity_pads_init(&video->video.entity, 1, &video->pad);
        if (ret < 0)
                return ERR_PTR(ret);

        /* ... and the format ... */
        rwpf->fmtinfo = vsp1_get_format_info(VSP1_VIDEO_DEF_FORMAT);
        rwpf->format.pixelformat = rwpf->fmtinfo->fourcc;
        rwpf->format.colorspace = V4L2_COLORSPACE_SRGB;
        rwpf->format.field = V4L2_FIELD_NONE;
        rwpf->format.width = VSP1_VIDEO_DEF_WIDTH;
        rwpf->format.height = VSP1_VIDEO_DEF_HEIGHT;
        rwpf->format.num_planes = 1;
        rwpf->format.plane_fmt[0].bytesperline =
                rwpf->format.width * rwpf->fmtinfo->bpp[0] / 8;
        rwpf->format.plane_fmt[0].sizeimage =
                rwpf->format.plane_fmt[0].bytesperline * rwpf->format.height;

        /* ... and the video node... */
        video->video.v4l2_dev = &video->vsp1->v4l2_dev;
        video->video.fops = &vsp1_video_fops;
        snprintf(video->video.name, sizeof(video->video.name), "%s %s",
                 rwpf->entity.subdev.name, direction);
        video->video.vfl_type = VFL_TYPE_GRABBER;
        video->video.release = video_device_release_empty;
        video->video.ioctl_ops = &vsp1_video_ioctl_ops;

        video_set_drvdata(&video->video, video);

        /* ... and the buffers queue... */
        video->alloc_ctx = vb2_dma_contig_init_ctx(video->vsp1->dev);
        if (IS_ERR(video->alloc_ctx)) {
                ret = PTR_ERR(video->alloc_ctx);
                goto error;
        }

        video->queue.type = video->type;
        video->queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
        video->queue.lock = &video->lock;
        video->queue.drv_priv = video;
        video->queue.buf_struct_size = sizeof(struct vsp1_vb2_buffer);
        video->queue.ops = &vsp1_video_queue_qops;
        video->queue.mem_ops = &vb2_dma_contig_memops;
        video->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
        ret = vb2_queue_init(&video->queue);
        if (ret < 0) {
                dev_err(video->vsp1->dev, "failed to initialize vb2 queue\n");
                goto error;
        }

        /* ... and register the video device. */
        video->video.queue = &video->queue;
        ret = video_register_device(&video->video, VFL_TYPE_GRABBER, -1);
        if (ret < 0) {
                dev_err(video->vsp1->dev, "failed to register video device\n");
                goto error;
        }

        return video;

error:
        vb2_dma_contig_cleanup_ctx(video->alloc_ctx);
        vsp1_video_cleanup(video);
        return ERR_PTR(ret);
}

void vsp1_video_cleanup(struct vsp1_video *video)
{
        if (video_is_registered(&video->video))
                video_unregister_device(&video->video);

        vb2_dma_contig_cleanup_ctx(video->alloc_ctx);
        media_entity_cleanup(&video->video.entity);
}