// SPDX-License-Identifier: GPL-2.0+
/*
 * TI OMAP4 ISS V4L2 Driver - Generic video node
 *
 * Copyright (C) 2012 Texas Instruments, Inc.
 *
 * Author: Sergio Aguirre <sergio.a.aguirre@gmail.com>
 */

#include <linux/clk.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/module.h>

#include <media/v4l2-dev.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-mc.h>

#include <asm/cacheflush.h>

#include "iss_video.h"
#include "iss.h"

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

static struct iss_format_info formats[] = {
        { MEDIA_BUS_FMT_Y8_1X8, MEDIA_BUS_FMT_Y8_1X8,
          MEDIA_BUS_FMT_Y8_1X8, MEDIA_BUS_FMT_Y8_1X8,
          V4L2_PIX_FMT_GREY, 8, "Greyscale 8 bpp", },
        { MEDIA_BUS_FMT_Y10_1X10, MEDIA_BUS_FMT_Y10_1X10,
          MEDIA_BUS_FMT_Y10_1X10, MEDIA_BUS_FMT_Y8_1X8,
          V4L2_PIX_FMT_Y10, 10, "Greyscale 10 bpp", },
        { MEDIA_BUS_FMT_Y12_1X12, MEDIA_BUS_FMT_Y10_1X10,
          MEDIA_BUS_FMT_Y12_1X12, MEDIA_BUS_FMT_Y8_1X8,
          V4L2_PIX_FMT_Y12, 12, "Greyscale 12 bpp", },
        { MEDIA_BUS_FMT_SBGGR8_1X8, MEDIA_BUS_FMT_SBGGR8_1X8,
          MEDIA_BUS_FMT_SBGGR8_1X8, MEDIA_BUS_FMT_SBGGR8_1X8,
          V4L2_PIX_FMT_SBGGR8, 8, "BGGR Bayer 8 bpp", },
        { MEDIA_BUS_FMT_SGBRG8_1X8, MEDIA_BUS_FMT_SGBRG8_1X8,
          MEDIA_BUS_FMT_SGBRG8_1X8, MEDIA_BUS_FMT_SGBRG8_1X8,
          V4L2_PIX_FMT_SGBRG8, 8, "GBRG Bayer 8 bpp", },
        { MEDIA_BUS_FMT_SGRBG8_1X8, MEDIA_BUS_FMT_SGRBG8_1X8,
          MEDIA_BUS_FMT_SGRBG8_1X8, MEDIA_BUS_FMT_SGRBG8_1X8,
          V4L2_PIX_FMT_SGRBG8, 8, "GRBG Bayer 8 bpp", },
        { MEDIA_BUS_FMT_SRGGB8_1X8, MEDIA_BUS_FMT_SRGGB8_1X8,
          MEDIA_BUS_FMT_SRGGB8_1X8, MEDIA_BUS_FMT_SRGGB8_1X8,
          V4L2_PIX_FMT_SRGGB8, 8, "RGGB Bayer 8 bpp", },
        { MEDIA_BUS_FMT_SGRBG10_DPCM8_1X8, MEDIA_BUS_FMT_SGRBG10_DPCM8_1X8,
          MEDIA_BUS_FMT_SGRBG10_1X10, 0,
          V4L2_PIX_FMT_SGRBG10DPCM8, 8, "GRBG Bayer 10 bpp DPCM8",  },
        { MEDIA_BUS_FMT_SBGGR10_1X10, MEDIA_BUS_FMT_SBGGR10_1X10,
          MEDIA_BUS_FMT_SBGGR10_1X10, MEDIA_BUS_FMT_SBGGR8_1X8,
          V4L2_PIX_FMT_SBGGR10, 10, "BGGR Bayer 10 bpp", },
        { MEDIA_BUS_FMT_SGBRG10_1X10, MEDIA_BUS_FMT_SGBRG10_1X10,
          MEDIA_BUS_FMT_SGBRG10_1X10, MEDIA_BUS_FMT_SGBRG8_1X8,
          V4L2_PIX_FMT_SGBRG10, 10, "GBRG Bayer 10 bpp", },
        { MEDIA_BUS_FMT_SGRBG10_1X10, MEDIA_BUS_FMT_SGRBG10_1X10,
          MEDIA_BUS_FMT_SGRBG10_1X10, MEDIA_BUS_FMT_SGRBG8_1X8,
          V4L2_PIX_FMT_SGRBG10, 10, "GRBG Bayer 10 bpp", },
        { MEDIA_BUS_FMT_SRGGB10_1X10, MEDIA_BUS_FMT_SRGGB10_1X10,
          MEDIA_BUS_FMT_SRGGB10_1X10, MEDIA_BUS_FMT_SRGGB8_1X8,
          V4L2_PIX_FMT_SRGGB10, 10, "RGGB Bayer 10 bpp", },
        { MEDIA_BUS_FMT_SBGGR12_1X12, MEDIA_BUS_FMT_SBGGR10_1X10,
          MEDIA_BUS_FMT_SBGGR12_1X12, MEDIA_BUS_FMT_SBGGR8_1X8,
          V4L2_PIX_FMT_SBGGR12, 12, "BGGR Bayer 12 bpp", },
        { MEDIA_BUS_FMT_SGBRG12_1X12, MEDIA_BUS_FMT_SGBRG10_1X10,
          MEDIA_BUS_FMT_SGBRG12_1X12, MEDIA_BUS_FMT_SGBRG8_1X8,
          V4L2_PIX_FMT_SGBRG12, 12, "GBRG Bayer 12 bpp", },
        { MEDIA_BUS_FMT_SGRBG12_1X12, MEDIA_BUS_FMT_SGRBG10_1X10,
          MEDIA_BUS_FMT_SGRBG12_1X12, MEDIA_BUS_FMT_SGRBG8_1X8,
          V4L2_PIX_FMT_SGRBG12, 12, "GRBG Bayer 12 bpp", },
        { MEDIA_BUS_FMT_SRGGB12_1X12, MEDIA_BUS_FMT_SRGGB10_1X10,
          MEDIA_BUS_FMT_SRGGB12_1X12, MEDIA_BUS_FMT_SRGGB8_1X8,
          V4L2_PIX_FMT_SRGGB12, 12, "RGGB Bayer 12 bpp", },
        { MEDIA_BUS_FMT_UYVY8_1X16, MEDIA_BUS_FMT_UYVY8_1X16,
          MEDIA_BUS_FMT_UYVY8_1X16, 0,
          V4L2_PIX_FMT_UYVY, 16, "YUV 4:2:2 (UYVY)", },
        { MEDIA_BUS_FMT_YUYV8_1X16, MEDIA_BUS_FMT_YUYV8_1X16,
          MEDIA_BUS_FMT_YUYV8_1X16, 0,
          V4L2_PIX_FMT_YUYV, 16, "YUV 4:2:2 (YUYV)", },
        { MEDIA_BUS_FMT_YUYV8_1_5X8, MEDIA_BUS_FMT_YUYV8_1_5X8,
          MEDIA_BUS_FMT_YUYV8_1_5X8, 0,
          V4L2_PIX_FMT_NV12, 8, "YUV 4:2:0 (NV12)", },
};

const struct iss_format_info *
omap4iss_video_format_info(u32 code)
{
        unsigned int i;

        for (i = 0; i < ARRAY_SIZE(formats); ++i) {
                if (formats[i].code == code)
                        return &formats[i];
        }

        return NULL;
}

/*
 * iss_video_mbus_to_pix - Convert v4l2_mbus_framefmt to v4l2_pix_format
 * @video: ISS video instance
 * @mbus: v4l2_mbus_framefmt format (input)
 * @pix: v4l2_pix_format format (output)
 *
 * Fill the output pix structure with information from the input mbus format.
 * The bytesperline and sizeimage fields are computed from the requested bytes
 * per line value in the pix format and information from the video instance.
 *
 * Return the number of padding bytes at end of line.
 */
static unsigned int iss_video_mbus_to_pix(const struct iss_video *video,
                                          const struct v4l2_mbus_framefmt *mbus,
                                          struct v4l2_pix_format *pix)
{
        unsigned int bpl = pix->bytesperline;
        unsigned int min_bpl;
        unsigned int i;

        memset(pix, 0, sizeof(*pix));
        pix->width = mbus->width;
        pix->height = mbus->height;

        /*
         * Skip the last format in the loop so that it will be selected if no
         * match is found.
         */
        for (i = 0; i < ARRAY_SIZE(formats) - 1; ++i) {
                if (formats[i].code == mbus->code)
                        break;
        }

        min_bpl = pix->width * ALIGN(formats[i].bpp, 8) / 8;

        /*
         * Clamp the requested bytes per line value. If the maximum bytes per
         * line value is zero, the module doesn't support user configurable line
         * sizes. Override the requested value with the minimum in that case.
         */
        if (video->bpl_max)
                bpl = clamp(bpl, min_bpl, video->bpl_max);
        else
                bpl = min_bpl;

        if (!video->bpl_zero_padding || bpl != min_bpl)
                bpl = ALIGN(bpl, video->bpl_alignment);

        pix->pixelformat = formats[i].pixelformat;
        pix->bytesperline = bpl;
        pix->sizeimage = pix->bytesperline * pix->height;
        pix->colorspace = mbus->colorspace;
        pix->field = mbus->field;

        /* FIXME: Special case for NV12! We should make this nicer... */
        if (pix->pixelformat == V4L2_PIX_FMT_NV12)
                pix->sizeimage += (pix->bytesperline * pix->height) / 2;

        return bpl - min_bpl;
}

static void iss_video_pix_to_mbus(const struct v4l2_pix_format *pix,
                                  struct v4l2_mbus_framefmt *mbus)
{
        unsigned int i;

        memset(mbus, 0, sizeof(*mbus));
        mbus->width = pix->width;
        mbus->height = pix->height;

        /*
         * Skip the last format in the loop so that it will be selected if no
         * match is found.
         */
        for (i = 0; i < ARRAY_SIZE(formats) - 1; ++i) {
                if (formats[i].pixelformat == pix->pixelformat)
                        break;
        }

        mbus->code = formats[i].code;
        mbus->colorspace = pix->colorspace;
        mbus->field = pix->field;
}

static struct v4l2_subdev *
iss_video_remote_subdev(struct iss_video *video, u32 *pad)
{
        struct media_pad *remote;

        remote = media_entity_remote_pad(&video->pad);

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

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

        return media_entity_to_v4l2_subdev(remote->entity);
}

/* Return a pointer to the ISS video instance at the far end of the pipeline. */
static struct iss_video *
iss_video_far_end(struct iss_video *video)
{
        struct media_graph graph;
        struct media_entity *entity = &video->video.entity;
        struct media_device *mdev = entity->graph_obj.mdev;
        struct iss_video *far_end = NULL;

        mutex_lock(&mdev->graph_mutex);

        if (media_graph_walk_init(&graph, mdev)) {
                mutex_unlock(&mdev->graph_mutex);
                return NULL;
        }

        media_graph_walk_start(&graph, entity);

        while ((entity = media_graph_walk_next(&graph))) {
                if (entity == &video->video.entity)
                        continue;

                if (!is_media_entity_v4l2_video_device(entity))
                        continue;

                far_end = to_iss_video(media_entity_to_video_device(entity));
                if (far_end->type != video->type)
                        break;

                far_end = NULL;
        }

        mutex_unlock(&mdev->graph_mutex);

        media_graph_walk_cleanup(&graph);

        return far_end;
}

static int
__iss_video_get_format(struct iss_video *video,
                       struct v4l2_mbus_framefmt *format)
{
        struct v4l2_subdev_format fmt;
        struct v4l2_subdev *subdev;
        u32 pad;
        int ret;

        subdev = iss_video_remote_subdev(video, &pad);
        if (!subdev)
                return -EINVAL;

        memset(&fmt, 0, sizeof(fmt));
        fmt.pad = pad;
        fmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;

        mutex_lock(&video->mutex);
        ret = v4l2_subdev_call(subdev, pad, get_fmt, NULL, &fmt);
        mutex_unlock(&video->mutex);

        if (ret)
                return ret;

        *format = fmt.format;
        return 0;
}

static int
iss_video_check_format(struct iss_video *video, struct iss_video_fh *vfh)
{
        struct v4l2_mbus_framefmt format;
        struct v4l2_pix_format pixfmt;
        int ret;

        ret = __iss_video_get_format(video, &format);
        if (ret < 0)
                return ret;

        pixfmt.bytesperline = 0;
        ret = iss_video_mbus_to_pix(video, &format, &pixfmt);

        if (vfh->format.fmt.pix.pixelformat != pixfmt.pixelformat ||
            vfh->format.fmt.pix.height != pixfmt.height ||
            vfh->format.fmt.pix.width != pixfmt.width ||
            vfh->format.fmt.pix.bytesperline != pixfmt.bytesperline ||
            vfh->format.fmt.pix.sizeimage != pixfmt.sizeimage)
                return -EINVAL;

        return ret;
}

/* -----------------------------------------------------------------------------
 * Video queue operations
 */

static int iss_video_queue_setup(struct vb2_queue *vq,
                                 unsigned int *count, unsigned int *num_planes,
                                 unsigned int sizes[],
                                 struct device *alloc_devs[])
{
        struct iss_video_fh *vfh = vb2_get_drv_priv(vq);
        struct iss_video *video = vfh->video;

        /* Revisit multi-planar support for NV12 */
        *num_planes = 1;

        sizes[0] = vfh->format.fmt.pix.sizeimage;
        if (sizes[0] == 0)
                return -EINVAL;

        *count = min(*count, video->capture_mem / PAGE_ALIGN(sizes[0]));

        return 0;
}

static void iss_video_buf_cleanup(struct vb2_buffer *vb)
{
        struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
        struct iss_buffer *buffer = container_of(vbuf, struct iss_buffer, vb);

        if (buffer->iss_addr)
                buffer->iss_addr = 0;
}

static int iss_video_buf_prepare(struct vb2_buffer *vb)
{
        struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
        struct iss_video_fh *vfh = vb2_get_drv_priv(vb->vb2_queue);
        struct iss_buffer *buffer = container_of(vbuf, struct iss_buffer, vb);
        struct iss_video *video = vfh->video;
        unsigned long size = vfh->format.fmt.pix.sizeimage;
        dma_addr_t addr;

        if (vb2_plane_size(vb, 0) < size)
                return -ENOBUFS;

        addr = vb2_dma_contig_plane_dma_addr(vb, 0);
        if (!IS_ALIGNED(addr, 32)) {
                dev_dbg(video->iss->dev,
                        "Buffer address must be aligned to 32 bytes boundary.\n");
                return -EINVAL;
        }

        vb2_set_plane_payload(vb, 0, size);
        buffer->iss_addr = addr;
        return 0;
}

static void iss_video_buf_queue(struct vb2_buffer *vb)
{
        struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
        struct iss_video_fh *vfh = vb2_get_drv_priv(vb->vb2_queue);
        struct iss_video *video = vfh->video;
        struct iss_buffer *buffer = container_of(vbuf, struct iss_buffer, vb);
        struct iss_pipeline *pipe = to_iss_pipeline(&video->video.entity);
        unsigned long flags;
        bool empty;

        spin_lock_irqsave(&video->qlock, flags);

        /*
         * Mark the buffer is faulty and give it back to the queue immediately
         * if the video node has registered an error. vb2 will perform the same
         * check when preparing the buffer, but that is inherently racy, so we
         * need to handle the race condition with an authoritative check here.
         */
        if (unlikely(video->error)) {
                vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
                spin_unlock_irqrestore(&video->qlock, flags);
                return;
        }

        empty = list_empty(&video->dmaqueue);
        list_add_tail(&buffer->list, &video->dmaqueue);

        spin_unlock_irqrestore(&video->qlock, flags);

        if (empty) {
                enum iss_pipeline_state state;
                unsigned int start;

                if (video->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
                        state = ISS_PIPELINE_QUEUE_OUTPUT;
                else
                        state = ISS_PIPELINE_QUEUE_INPUT;

                spin_lock_irqsave(&pipe->lock, flags);
                pipe->state |= state;
                video->ops->queue(video, buffer);
                video->dmaqueue_flags |= ISS_VIDEO_DMAQUEUE_QUEUED;

                start = iss_pipeline_ready(pipe);
                if (start)
                        pipe->state |= ISS_PIPELINE_STREAM;
                spin_unlock_irqrestore(&pipe->lock, flags);

                if (start)
                        omap4iss_pipeline_set_stream(pipe,
                                                ISS_PIPELINE_STREAM_SINGLESHOT);
        }
}

static const struct vb2_ops iss_video_vb2ops = {
        .queue_setup    = iss_video_queue_setup,
        .buf_prepare    = iss_video_buf_prepare,
        .buf_queue      = iss_video_buf_queue,
        .buf_cleanup    = iss_video_buf_cleanup,
};

/*
 * omap4iss_video_buffer_next - Complete the current buffer and return the next
 * @video: ISS video object
 *
 * Remove the current video buffer from the DMA queue and fill its timestamp,
 * field count and state fields before waking up its completion handler.
 *
 * For capture video nodes, the buffer state is set to VB2_BUF_STATE_DONE if no
 * error has been flagged in the pipeline, or to VB2_BUF_STATE_ERROR otherwise.
 *
 * The DMA queue is expected to contain at least one buffer.
 *
 * Return a pointer to the next buffer in the DMA queue, or NULL if the queue is
 * empty.
 */
struct iss_buffer *omap4iss_video_buffer_next(struct iss_video *video)
{
        struct iss_pipeline *pipe = to_iss_pipeline(&video->video.entity);
        enum iss_pipeline_state state;
        struct iss_buffer *buf;
        unsigned long flags;

        spin_lock_irqsave(&video->qlock, flags);
        if (WARN_ON(list_empty(&video->dmaqueue))) {
                spin_unlock_irqrestore(&video->qlock, flags);
                return NULL;
        }

        buf = list_first_entry(&video->dmaqueue, struct iss_buffer,
                               list);
        list_del(&buf->list);
        spin_unlock_irqrestore(&video->qlock, flags);

        buf->vb.vb2_buf.timestamp = ktime_get_ns();

        /*
         * Do frame number propagation only if this is the output video node.
         * Frame number either comes from the CSI receivers or it gets
         * incremented here if H3A is not active.
         * Note: There is no guarantee that the output buffer will finish
         * first, so the input number might lag behind by 1 in some cases.
         */
        if (video == pipe->output && !pipe->do_propagation)
                buf->vb.sequence =
                        atomic_inc_return(&pipe->frame_number);
        else
                buf->vb.sequence = atomic_read(&pipe->frame_number);

        vb2_buffer_done(&buf->vb.vb2_buf, pipe->error ?
                        VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
        pipe->error = false;

        spin_lock_irqsave(&video->qlock, flags);
        if (list_empty(&video->dmaqueue)) {
                spin_unlock_irqrestore(&video->qlock, flags);
                if (video->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
                        state = ISS_PIPELINE_QUEUE_OUTPUT
                              | ISS_PIPELINE_STREAM;
                else
                        state = ISS_PIPELINE_QUEUE_INPUT
                              | ISS_PIPELINE_STREAM;

                spin_lock_irqsave(&pipe->lock, flags);
                pipe->state &= ~state;
                if (video->pipe.stream_state == ISS_PIPELINE_STREAM_CONTINUOUS)
                        video->dmaqueue_flags |= ISS_VIDEO_DMAQUEUE_UNDERRUN;
                spin_unlock_irqrestore(&pipe->lock, flags);
                return NULL;
        }

        if (video->type == V4L2_BUF_TYPE_VIDEO_CAPTURE && pipe->input) {
                spin_lock(&pipe->lock);
                pipe->state &= ~ISS_PIPELINE_STREAM;
                spin_unlock(&pipe->lock);
        }

        buf = list_first_entry(&video->dmaqueue, struct iss_buffer,
                               list);
        spin_unlock_irqrestore(&video->qlock, flags);
        buf->vb.vb2_buf.state = VB2_BUF_STATE_ACTIVE;
        return buf;
}

/*
 * omap4iss_video_cancel_stream - Cancel stream on a video node
 * @video: ISS video object
 *
 * Cancelling a stream mark all buffers on the video node as erroneous and makes
 * sure no new buffer can be queued.
 */
void omap4iss_video_cancel_stream(struct iss_video *video)
{
        unsigned long flags;

        spin_lock_irqsave(&video->qlock, flags);

        while (!list_empty(&video->dmaqueue)) {
                struct iss_buffer *buf;

                buf = list_first_entry(&video->dmaqueue, struct iss_buffer,
                                       list);
                list_del(&buf->list);
                vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
        }

        vb2_queue_error(video->queue);
        video->error = true;

        spin_unlock_irqrestore(&video->qlock, flags);
}

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

static int
iss_video_querycap(struct file *file, void *fh, struct v4l2_capability *cap)
{
        struct iss_video *video = video_drvdata(file);

        strscpy(cap->driver, ISS_VIDEO_DRIVER_NAME, sizeof(cap->driver));
        strscpy(cap->card, video->video.name, sizeof(cap->card));
        strscpy(cap->bus_info, "media", sizeof(cap->bus_info));
        cap->capabilities = V4L2_CAP_DEVICE_CAPS | V4L2_CAP_STREAMING
                          | V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_VIDEO_OUTPUT;

        return 0;
}

static int
iss_video_enum_format(struct file *file, void *fh, struct v4l2_fmtdesc *f)
{
        struct iss_video *video = video_drvdata(file);
        struct v4l2_mbus_framefmt format;
        unsigned int index = f->index;
        unsigned int i;
        int ret;

        if (f->type != video->type)
                return -EINVAL;

        ret = __iss_video_get_format(video, &format);
        if (ret < 0)
                return ret;

        for (i = 0; i < ARRAY_SIZE(formats); ++i) {
                const struct iss_format_info *info = &formats[i];

                if (format.code != info->code)
                        continue;

                if (index == 0) {
                        f->pixelformat = info->pixelformat;
                        strscpy(f->description, info->description,
                                sizeof(f->description));
                        return 0;
                }

                index--;
        }

        return -EINVAL;
}

static int
iss_video_get_format(struct file *file, void *fh, struct v4l2_format *format)
{
        struct iss_video_fh *vfh = to_iss_video_fh(fh);
        struct iss_video *video = video_drvdata(file);

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

        mutex_lock(&video->mutex);
        *format = vfh->format;
        mutex_unlock(&video->mutex);

        return 0;
}

static int
iss_video_set_format(struct file *file, void *fh, struct v4l2_format *format)
{
        struct iss_video_fh *vfh = to_iss_video_fh(fh);
        struct iss_video *video = video_drvdata(file);
        struct v4l2_mbus_framefmt fmt;

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

        mutex_lock(&video->mutex);

        /*
         * Fill the bytesperline and sizeimage fields by converting to media bus
         * format and back to pixel format.
         */
        iss_video_pix_to_mbus(&format->fmt.pix, &fmt);
        iss_video_mbus_to_pix(video, &fmt, &format->fmt.pix);

        vfh->format = *format;

        mutex_unlock(&video->mutex);
        return 0;
}

static int
iss_video_try_format(struct file *file, void *fh, struct v4l2_format *format)
{
        struct iss_video *video = video_drvdata(file);
        struct v4l2_subdev_format fmt;
        struct v4l2_subdev *subdev;
        u32 pad;
        int ret;

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

        subdev = iss_video_remote_subdev(video, &pad);
        if (!subdev)
                return -EINVAL;

        iss_video_pix_to_mbus(&format->fmt.pix, &fmt.format);

        fmt.pad = pad;
        fmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
        ret = v4l2_subdev_call(subdev, pad, get_fmt, NULL, &fmt);
        if (ret)
                return ret;

        iss_video_mbus_to_pix(video, &fmt.format, &format->fmt.pix);
        return 0;
}

static int
iss_video_get_selection(struct file *file, void *fh, struct v4l2_selection *sel)
{
        struct iss_video *video = video_drvdata(file);
        struct v4l2_subdev_format format;
        struct v4l2_subdev *subdev;
        struct v4l2_subdev_selection sdsel = {
                .which = V4L2_SUBDEV_FORMAT_ACTIVE,
                .target = sel->target,
        };
        u32 pad;
        int ret;

        switch (sel->target) {
        case V4L2_SEL_TGT_CROP:
        case V4L2_SEL_TGT_CROP_BOUNDS:
        case V4L2_SEL_TGT_CROP_DEFAULT:
                if (video->type == V4L2_BUF_TYPE_VIDEO_OUTPUT)
                        return -EINVAL;
                break;
        case V4L2_SEL_TGT_COMPOSE:
        case V4L2_SEL_TGT_COMPOSE_BOUNDS:
        case V4L2_SEL_TGT_COMPOSE_DEFAULT:
                if (video->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
                        return -EINVAL;
                break;
        default:
                return -EINVAL;
        }
        subdev = iss_video_remote_subdev(video, &pad);
        if (subdev == NULL)
                return -EINVAL;

        /*
         * Try the get selection operation first and fallback to get format if
         * not implemented.
         */
        sdsel.pad = pad;
        ret = v4l2_subdev_call(subdev, pad, get_selection, NULL, &sdsel);
        if (!ret)
                sel->r = sdsel.r;
        if (ret != -ENOIOCTLCMD)
                return ret;

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

        sel->r.left = 0;
        sel->r.top = 0;
        sel->r.width = format.format.width;
        sel->r.height = format.format.height;

        return 0;
}

static int
iss_video_set_selection(struct file *file, void *fh, struct v4l2_selection *sel)
{
        struct iss_video *video = video_drvdata(file);
        struct v4l2_subdev *subdev;
        struct v4l2_subdev_selection sdsel = {
                .which = V4L2_SUBDEV_FORMAT_ACTIVE,
                .target = sel->target,
                .flags = sel->flags,
                .r = sel->r,
        };
        u32 pad;
        int ret;

        switch (sel->target) {
        case V4L2_SEL_TGT_CROP:
                if (video->type == V4L2_BUF_TYPE_VIDEO_OUTPUT)
                        return -EINVAL;
                break;
        case V4L2_SEL_TGT_COMPOSE:
                if (video->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
                        return -EINVAL;
                break;
        default:
                return -EINVAL;
        }
        subdev = iss_video_remote_subdev(video, &pad);
        if (subdev == NULL)
                return -EINVAL;

        sdsel.pad = pad;
        mutex_lock(&video->mutex);
        ret = v4l2_subdev_call(subdev, pad, set_selection, NULL, &sdsel);
        mutex_unlock(&video->mutex);
        if (!ret)
                sel->r = sdsel.r;

        return ret == -ENOIOCTLCMD ? -ENOTTY : ret;
}

static int
iss_video_get_param(struct file *file, void *fh, struct v4l2_streamparm *a)
{
        struct iss_video_fh *vfh = to_iss_video_fh(fh);
        struct iss_video *video = video_drvdata(file);

        if (video->type != V4L2_BUF_TYPE_VIDEO_OUTPUT ||
            video->type != a->type)
                return -EINVAL;

        memset(a, 0, sizeof(*a));
        a->type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
        a->parm.output.capability = V4L2_CAP_TIMEPERFRAME;
        a->parm.output.timeperframe = vfh->timeperframe;

        return 0;
}

static int
iss_video_set_param(struct file *file, void *fh, struct v4l2_streamparm *a)
{
        struct iss_video_fh *vfh = to_iss_video_fh(fh);
        struct iss_video *video = video_drvdata(file);

        if (video->type != V4L2_BUF_TYPE_VIDEO_OUTPUT ||
            video->type != a->type)
                return -EINVAL;

        if (a->parm.output.timeperframe.denominator == 0)
                a->parm.output.timeperframe.denominator = 1;

        vfh->timeperframe = a->parm.output.timeperframe;

        return 0;
}

static int
iss_video_reqbufs(struct file *file, void *fh, struct v4l2_requestbuffers *rb)
{
        struct iss_video_fh *vfh = to_iss_video_fh(fh);

        return vb2_reqbufs(&vfh->queue, rb);
}

static int
iss_video_querybuf(struct file *file, void *fh, struct v4l2_buffer *b)
{
        struct iss_video_fh *vfh = to_iss_video_fh(fh);

        return vb2_querybuf(&vfh->queue, b);
}

static int
iss_video_qbuf(struct file *file, void *fh, struct v4l2_buffer *b)
{
        struct iss_video *video = video_drvdata(file);
        struct iss_video_fh *vfh = to_iss_video_fh(fh);

        return vb2_qbuf(&vfh->queue, video->video.v4l2_dev->mdev, b);
}

static int
iss_video_expbuf(struct file *file, void *fh, struct v4l2_exportbuffer *e)
{
        struct iss_video_fh *vfh = to_iss_video_fh(fh);

        return vb2_expbuf(&vfh->queue, e);
}

static int
iss_video_dqbuf(struct file *file, void *fh, struct v4l2_buffer *b)
{
        struct iss_video_fh *vfh = to_iss_video_fh(fh);

        return vb2_dqbuf(&vfh->queue, b, file->f_flags & O_NONBLOCK);
}

/*
 * Stream management
 *
 * Every ISS pipeline has a single input and a single output. The input can be
 * either a sensor or a video node. The output is always a video node.
 *
 * As every pipeline has an output video node, the ISS video objects at the
 * pipeline output stores the pipeline state. It tracks the streaming state of
 * both the input and output, as well as the availability of buffers.
 *
 * In sensor-to-memory mode, frames are always available at the pipeline input.
 * Starting the sensor usually requires I2C transfers and must be done in
 * interruptible context. The pipeline is started and stopped synchronously
 * to the stream on/off commands. All modules in the pipeline will get their
 * subdev set stream handler called. The module at the end of the pipeline must
 * delay starting the hardware until buffers are available at its output.
 *
 * In memory-to-memory mode, starting/stopping the stream requires
 * synchronization between the input and output. ISS modules can't be stopped
 * in the middle of a frame, and at least some of the modules seem to become
 * busy as soon as they're started, even if they don't receive a frame start
 * event. For that reason frames need to be processed in single-shot mode. The
 * driver needs to wait until a frame is completely processed and written to
 * memory before restarting the pipeline for the next frame. Pipelined
 * processing might be possible but requires more testing.
 *
 * Stream start must be delayed until buffers are available at both the input
 * and output. The pipeline must be started in the videobuf queue callback with
 * the buffers queue spinlock held. The modules subdev set stream operation must
 * not sleep.
 */
static int
iss_video_streamon(struct file *file, void *fh, enum v4l2_buf_type type)
{
        struct iss_video_fh *vfh = to_iss_video_fh(fh);
        struct iss_video *video = video_drvdata(file);
        struct media_graph graph;
        struct media_entity *entity = &video->video.entity;
        enum iss_pipeline_state state;
        struct iss_pipeline *pipe;
        struct iss_video *far_end;
        unsigned long flags;
        int ret;

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

        mutex_lock(&video->stream_lock);

        /*
         * Start streaming on the pipeline. No link touching an entity in the
         * pipeline can be activated or deactivated once streaming is started.
         */
        pipe = entity->pipe
             ? to_iss_pipeline(entity) : &video->pipe;
        pipe->external = NULL;
        pipe->external_rate = 0;
        pipe->external_bpp = 0;

        ret = media_entity_enum_init(&pipe->ent_enum, entity->graph_obj.mdev);
        if (ret)
                goto err_graph_walk_init;

        ret = media_graph_walk_init(&graph, entity->graph_obj.mdev);
        if (ret)
                goto err_graph_walk_init;

        if (video->iss->pdata->set_constraints)
                video->iss->pdata->set_constraints(video->iss, true);

        ret = media_pipeline_start(entity, &pipe->pipe);
        if (ret < 0)
                goto err_media_pipeline_start;

        media_graph_walk_start(&graph, entity);
        while ((entity = media_graph_walk_next(&graph)))
                media_entity_enum_set(&pipe->ent_enum, entity);

        /*
         * Verify that the currently configured format matches the output of
         * the connected subdev.
         */
        ret = iss_video_check_format(video, vfh);
        if (ret < 0)
                goto err_iss_video_check_format;

        video->bpl_padding = ret;
        video->bpl_value = vfh->format.fmt.pix.bytesperline;

        /*
         * Find the ISS video node connected at the far end of the pipeline and
         * update the pipeline.
         */
        far_end = iss_video_far_end(video);

        if (video->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
                state = ISS_PIPELINE_STREAM_OUTPUT | ISS_PIPELINE_IDLE_OUTPUT;
                pipe->input = far_end;
                pipe->output = video;
        } else {
                if (!far_end) {
                        ret = -EPIPE;
                        goto err_iss_video_check_format;
                }

                state = ISS_PIPELINE_STREAM_INPUT | ISS_PIPELINE_IDLE_INPUT;
                pipe->input = video;
                pipe->output = far_end;
        }

        spin_lock_irqsave(&pipe->lock, flags);
        pipe->state &= ~ISS_PIPELINE_STREAM;
        pipe->state |= state;
        spin_unlock_irqrestore(&pipe->lock, flags);

        /*
         * Set the maximum time per frame as the value requested by userspace.
         * This is a soft limit that can be overridden if the hardware doesn't
         * support the request limit.
         */
        if (video->type == V4L2_BUF_TYPE_VIDEO_OUTPUT)
                pipe->max_timeperframe = vfh->timeperframe;

        video->queue = &vfh->queue;
        INIT_LIST_HEAD(&video->dmaqueue);
        video->error = false;
        atomic_set(&pipe->frame_number, -1);

        ret = vb2_streamon(&vfh->queue, type);
        if (ret < 0)
                goto err_iss_video_check_format;

        /*
         * In sensor-to-memory mode, the stream can be started synchronously
         * to the stream on command. In memory-to-memory mode, it will be
         * started when buffers are queued on both the input and output.
         */
        if (!pipe->input) {
                unsigned long flags;

                ret = omap4iss_pipeline_set_stream(pipe,
                                              ISS_PIPELINE_STREAM_CONTINUOUS);
                if (ret < 0)
                        goto err_omap4iss_set_stream;
                spin_lock_irqsave(&video->qlock, flags);
                if (list_empty(&video->dmaqueue))
                        video->dmaqueue_flags |= ISS_VIDEO_DMAQUEUE_UNDERRUN;
                spin_unlock_irqrestore(&video->qlock, flags);
        }

        media_graph_walk_cleanup(&graph);

        mutex_unlock(&video->stream_lock);

        return 0;

err_omap4iss_set_stream:
        vb2_streamoff(&vfh->queue, type);
err_iss_video_check_format:
        media_pipeline_stop(&video->video.entity);
err_media_pipeline_start:
        if (video->iss->pdata->set_constraints)
                video->iss->pdata->set_constraints(video->iss, false);
        video->queue = NULL;

        media_graph_walk_cleanup(&graph);

err_graph_walk_init:
        media_entity_enum_cleanup(&pipe->ent_enum);

        mutex_unlock(&video->stream_lock);

        return ret;
}

static int
iss_video_streamoff(struct file *file, void *fh, enum v4l2_buf_type type)
{
        struct iss_video_fh *vfh = to_iss_video_fh(fh);
        struct iss_video *video = video_drvdata(file);

        struct iss_pipeline *pipe = to_iss_pipeline(&video->video.entity);
        enum iss_pipeline_state state;
        unsigned long flags;

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

        mutex_lock(&video->stream_lock);

        if (!vb2_is_streaming(&vfh->queue))
                goto done;

        /* Update the pipeline state. */
        if (video->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
                state = ISS_PIPELINE_STREAM_OUTPUT
                      | ISS_PIPELINE_QUEUE_OUTPUT;
        else
                state = ISS_PIPELINE_STREAM_INPUT
                      | ISS_PIPELINE_QUEUE_INPUT;

        spin_lock_irqsave(&pipe->lock, flags);
        pipe->state &= ~state;
        spin_unlock_irqrestore(&pipe->lock, flags);

        /* Stop the stream. */
        omap4iss_pipeline_set_stream(pipe, ISS_PIPELINE_STREAM_STOPPED);
        vb2_streamoff(&vfh->queue, type);
        video->queue = NULL;

        media_entity_enum_cleanup(&pipe->ent_enum);

        if (video->iss->pdata->set_constraints)
                video->iss->pdata->set_constraints(video->iss, false);
        media_pipeline_stop(&video->video.entity);

done:
        mutex_unlock(&video->stream_lock);
        return 0;
}

static int
iss_video_enum_input(struct file *file, void *fh, struct v4l2_input *input)
{
        if (input->index > 0)
                return -EINVAL;

        strscpy(input->name, "camera", sizeof(input->name));
        input->type = V4L2_INPUT_TYPE_CAMERA;

        return 0;
}

static int
iss_video_g_input(struct file *file, void *fh, unsigned int *input)
{
        *input = 0;

        return 0;
}

static int
iss_video_s_input(struct file *file, void *fh, unsigned int input)
{
        return input == 0 ? 0 : -EINVAL;
}

static const struct v4l2_ioctl_ops iss_video_ioctl_ops = {
        .vidioc_querycap                = iss_video_querycap,
        .vidioc_enum_fmt_vid_cap        = iss_video_enum_format,
        .vidioc_g_fmt_vid_cap           = iss_video_get_format,
        .vidioc_s_fmt_vid_cap           = iss_video_set_format,
        .vidioc_try_fmt_vid_cap         = iss_video_try_format,
        .vidioc_g_fmt_vid_out           = iss_video_get_format,
        .vidioc_s_fmt_vid_out           = iss_video_set_format,
        .vidioc_try_fmt_vid_out         = iss_video_try_format,
        .vidioc_g_selection             = iss_video_get_selection,
        .vidioc_s_selection             = iss_video_set_selection,
        .vidioc_g_parm                  = iss_video_get_param,
        .vidioc_s_parm                  = iss_video_set_param,
        .vidioc_reqbufs                 = iss_video_reqbufs,
        .vidioc_querybuf                = iss_video_querybuf,
        .vidioc_qbuf                    = iss_video_qbuf,
        .vidioc_expbuf                  = iss_video_expbuf,
        .vidioc_dqbuf                   = iss_video_dqbuf,
        .vidioc_streamon                = iss_video_streamon,
        .vidioc_streamoff               = iss_video_streamoff,
        .vidioc_enum_input              = iss_video_enum_input,
        .vidioc_g_input                 = iss_video_g_input,
        .vidioc_s_input                 = iss_video_s_input,
};

/* -----------------------------------------------------------------------------
 * V4L2 file operations
 */

static int iss_video_open(struct file *file)
{
        struct iss_video *video = video_drvdata(file);
        struct iss_video_fh *handle;
        struct vb2_queue *q;
        int ret = 0;

        handle = kzalloc(sizeof(*handle), GFP_KERNEL);
        if (!handle)
                return -ENOMEM;

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

        /* If this is the first user, initialise the pipeline. */
        if (!omap4iss_get(video->iss)) {
                ret = -EBUSY;
                goto done;
        }

        ret = v4l2_pipeline_pm_use(&video->video.entity, 1);
        if (ret < 0) {
                omap4iss_put(video->iss);
                goto done;
        }

        q = &handle->queue;

        q->type = video->type;
        q->io_modes = VB2_MMAP | VB2_DMABUF;
        q->drv_priv = handle;
        q->ops = &iss_video_vb2ops;
        q->mem_ops = &vb2_dma_contig_memops;
        q->buf_struct_size = sizeof(struct iss_buffer);
        q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
        q->dev = video->iss->dev;

        ret = vb2_queue_init(q);
        if (ret) {
                omap4iss_put(video->iss);
                goto done;
        }

        memset(&handle->format, 0, sizeof(handle->format));
        handle->format.type = video->type;
        handle->timeperframe.denominator = 1;

        handle->video = video;
        file->private_data = &handle->vfh;

done:
        if (ret < 0) {
                v4l2_fh_del(&handle->vfh);
                v4l2_fh_exit(&handle->vfh);
                kfree(handle);
        }

        return ret;
}

static int iss_video_release(struct file *file)
{
        struct iss_video *video = video_drvdata(file);
        struct v4l2_fh *vfh = file->private_data;
        struct iss_video_fh *handle = to_iss_video_fh(vfh);

        /* Disable streaming and free the buffers queue resources. */
        iss_video_streamoff(file, vfh, video->type);

        v4l2_pipeline_pm_use(&video->video.entity, 0);

        /* Release the videobuf2 queue */
        vb2_queue_release(&handle->queue);

        v4l2_fh_del(vfh);
        v4l2_fh_exit(vfh);
        kfree(handle);
        file->private_data = NULL;

        omap4iss_put(video->iss);

        return 0;
}

static __poll_t iss_video_poll(struct file *file, poll_table *wait)
{
        struct iss_video_fh *vfh = to_iss_video_fh(file->private_data);

        return vb2_poll(&vfh->queue, file, wait);
}

static int iss_video_mmap(struct file *file, struct vm_area_struct *vma)
{
        struct iss_video_fh *vfh = to_iss_video_fh(file->private_data);

        return vb2_mmap(&vfh->queue, vma);
}

static const struct v4l2_file_operations iss_video_fops = {
        .owner = THIS_MODULE,
        .unlocked_ioctl = video_ioctl2,
        .open = iss_video_open,
        .release = iss_video_release,
        .poll = iss_video_poll,
        .mmap = iss_video_mmap,
};

/* -----------------------------------------------------------------------------
 * ISS video core
 */

static const struct iss_video_operations iss_video_dummy_ops = {
};

int omap4iss_video_init(struct iss_video *video, const char *name)
{
        const char *direction;
        int ret;

        switch (video->type) {
        case V4L2_BUF_TYPE_VIDEO_CAPTURE:
                direction = "output";
                video->pad.flags = MEDIA_PAD_FL_SINK;
                break;
        case V4L2_BUF_TYPE_VIDEO_OUTPUT:
                direction = "input";
                video->pad.flags = MEDIA_PAD_FL_SOURCE;
                break;

        default:
                return -EINVAL;
        }

        ret = media_entity_pads_init(&video->video.entity, 1, &video->pad);
        if (ret < 0)
                return ret;

        spin_lock_init(&video->qlock);
        mutex_init(&video->mutex);
        atomic_set(&video->active, 0);

        spin_lock_init(&video->pipe.lock);
        mutex_init(&video->stream_lock);

        /* Initialize the video device. */
        if (!video->ops)
                video->ops = &iss_video_dummy_ops;

        video->video.fops = &iss_video_fops;
        snprintf(video->video.name, sizeof(video->video.name),
                 "OMAP4 ISS %s %s", name, direction);
        video->video.vfl_type = VFL_TYPE_GRABBER;
        video->video.release = video_device_release_empty;
        video->video.ioctl_ops = &iss_video_ioctl_ops;
        video->pipe.stream_state = ISS_PIPELINE_STREAM_STOPPED;

        video_set_drvdata(&video->video, video);

        return 0;
}

void omap4iss_video_cleanup(struct iss_video *video)
{
        media_entity_cleanup(&video->video.entity);
        mutex_destroy(&video->stream_lock);
        mutex_destroy(&video->mutex);
}

int omap4iss_video_register(struct iss_video *video, struct v4l2_device *vdev)
{
        int ret;

        video->video.v4l2_dev = vdev;
        if (video->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
                video->video.device_caps = V4L2_CAP_VIDEO_CAPTURE;
        else
                video->video.device_caps = V4L2_CAP_VIDEO_OUTPUT;
        video->video.device_caps |= V4L2_CAP_STREAMING;

        ret = video_register_device(&video->video, VFL_TYPE_GRABBER, -1);
        if (ret < 0)
                dev_err(video->iss->dev,
                        "could not register video device (%d)\n", ret);

        return ret;
}

void omap4iss_video_unregister(struct iss_video *video)
{
        video_unregister_device(&video->video);
}