A quick review:

On 11/08/2016 07:34 AM, Rick Chang wrote:

You probably don't need the name since it is filled in by the v4l2 core
(v4l2-ioctls.c).

+	},
+};
+
+#define MTK_JPEG_NUM_FORMATS ARRAY_SIZE(mtk_jpeg_formats)
+
+enum {
+	MTK_JPEG_BUF_FLAGS_INIT			= 0,
+	MTK_JPEG_BUF_FLAGS_LAST_FRAME		= 1,
+};
+
+struct mtk_jpeg_src_buf {
+	struct vb2_v4l2_buffer b;
+	struct list_head list;
+	int flags;
+	struct mtk_jpeg_dec_param dec_param;
+};
+
+static int debug;
+module_param(debug, int, 0644);
+
+static inline struct mtk_jpeg_ctx *mtk_jpeg_fh_to_ctx(struct v4l2_fh *fh)
+{
+	return container_of(fh, struct mtk_jpeg_ctx, fh);
+}
+
+static inline struct mtk_jpeg_src_buf *mtk_jpeg_vb2_to_srcbuf(
+							struct vb2_buffer *vb)
+{
+	return container_of(to_vb2_v4l2_buffer(vb), struct mtk_jpeg_src_buf, b);
+}
+
+static int mtk_jpeg_querycap(struct file *file, void *priv,
+			     struct v4l2_capability *cap)
+{
+	struct mtk_jpeg_dev *jpeg = video_drvdata(file);
+
+	strlcpy(cap->driver, MTK_JPEG_NAME " decoder", sizeof(cap->driver));
+	strlcpy(cap->card, MTK_JPEG_NAME " decoder", sizeof(cap->card));
+	snprintf(cap->bus_info, sizeof(cap->bus_info), "platform:%s",
+		 dev_name(jpeg->dev));
+
+	return 0;
+}
+
+static int mtk_jpeg_enum_fmt(struct mtk_jpeg_fmt *mtk_jpeg_formats, int n,
+			     struct v4l2_fmtdesc *f, u32 type)
+{
+	int i, num = 0;
+
+	for (i = 0; i < n; ++i) {
+		if (mtk_jpeg_formats[i].flags & type) {
+			if (num == f->index)
+				break;
+			++num;
+		}
+	}
+
+	if (i >= n)
+		return -EINVAL;
+
+	f->pixelformat = mtk_jpeg_formats[i].fourcc;
+
+	return 0;
+}
+
+static int mtk_jpeg_enum_fmt_vid_cap(struct file *file, void *priv,
+				     struct v4l2_fmtdesc *f)
+{
+	return mtk_jpeg_enum_fmt(mtk_jpeg_formats, MTK_JPEG_NUM_FORMATS, f,
+				 MTK_JPEG_FMT_FLAG_DEC_CAPTURE);
+}
+
+static int mtk_jpeg_enum_fmt_vid_out(struct file *file, void *priv,
+				     struct v4l2_fmtdesc *f)
+{
+	return mtk_jpeg_enum_fmt(mtk_jpeg_formats, MTK_JPEG_NUM_FORMATS, f,
+				 MTK_JPEG_FMT_FLAG_DEC_OUTPUT);
+}
+
+static struct mtk_jpeg_q_data *mtk_jpeg_get_q_data(struct mtk_jpeg_ctx *ctx,
+						   enum v4l2_buf_type type)
+{
+	if (V4L2_TYPE_IS_OUTPUT(type))
+		return &ctx->out_q;
+	else

No need for 'else'.

+		return &ctx->cap_q;
+}
+
+static struct mtk_jpeg_fmt *mtk_jpeg_find_format(struct mtk_jpeg_ctx *ctx,
+						 u32 pixelformat,
+						 unsigned int fmt_type)
+{
+	unsigned int k, fmt_flag;
+
+	fmt_flag = (fmt_type == MTK_JPEG_FMT_TYPE_OUTPUT) ?
+		   MTK_JPEG_FMT_FLAG_DEC_OUTPUT :
+		   MTK_JPEG_FMT_FLAG_DEC_CAPTURE;
+
+	for (k = 0; k < MTK_JPEG_NUM_FORMATS; k++) {
+		struct mtk_jpeg_fmt *fmt = &mtk_jpeg_formats[k];
+
+		if (fmt->fourcc == pixelformat && fmt->flags & fmt_flag)
+			return fmt;
+	}
+
+	return NULL;
+}
+
+static void mtk_jpeg_bound_align_image(u32 *w, unsigned int wmin,
+				       unsigned int wmax, unsigned int walign,
+				       u32 *h, unsigned int hmin,
+				       unsigned int hmax, unsigned int halign)
+{
+	int width, height, w_step, h_step;
+
+	width = *w;
+	height = *h;
+	w_step = 1 << walign;
+	h_step = 1 << halign;
+
+	v4l_bound_align_image(w, wmin, wmax, walign, h, hmin, hmax, halign, 0);
+	if (*w < width && (*w + w_step) <= wmax)
+		*w += w_step;
+	if (*h < height && (*h + h_step) <= hmax)
+		*h += h_step;
+}
+
+static void mtk_jpeg_adjust_fmt_mplane(struct mtk_jpeg_ctx *ctx,
+				       struct v4l2_format *f)
+{
+	struct v4l2_pix_format_mplane *pix_mp = &f->fmt.pix_mp;
+	struct mtk_jpeg_q_data *q_data;
+	int i;
+
+	q_data = mtk_jpeg_get_q_data(ctx, f->type);
+
+	pix_mp->width = q_data->w;
+	pix_mp->height = q_data->h;
+	pix_mp->pixelformat = q_data->fmt->fourcc;
+	pix_mp->num_planes = q_data->fmt->colplanes;
+
+	for (i = 0; i < pix_mp->num_planes; i++) {
+		pix_mp->plane_fmt[i].bytesperline = q_data->bytesperline[i];
+		pix_mp->plane_fmt[i].sizeimage = q_data->sizeimage[i];
+	}
+}
+
+static int mtk_jpeg_try_fmt_mplane(struct v4l2_format *f,
+				   struct mtk_jpeg_fmt *fmt,
+				   struct mtk_jpeg_ctx *ctx, int q_type)
+{
+	struct v4l2_pix_format_mplane *pix_mp = &f->fmt.pix_mp;
+	struct mtk_jpeg_dev *jpeg = ctx->jpeg;
+	int i;
+
+	memset(pix_mp->reserved, 0, sizeof(pix_mp->reserved));
+	pix_mp->field = V4L2_FIELD_NONE;
+
+	if (ctx->state != MTK_JPEG_INIT) {
+		mtk_jpeg_adjust_fmt_mplane(ctx, f);
+		goto end;
+	}
+
+	pix_mp->num_planes = fmt->colplanes;
+	pix_mp->pixelformat = fmt->fourcc;
+
+	if (q_type == MTK_JPEG_FMT_TYPE_OUTPUT) {
+		struct v4l2_plane_pix_format *pfmt = &pix_mp->plane_fmt[0];
+
+		mtk_jpeg_bound_align_image(&pix_mp->width, MTK_JPEG_MIN_WIDTH,
+					   MTK_JPEG_MAX_WIDTH, 0,
+					   &pix_mp->height, MTK_JPEG_MIN_HEIGHT,
+					   MTK_JPEG_MAX_HEIGHT, 0);
+
+		memset(pfmt->reserved, 0, sizeof(pfmt->reserved));
+		pfmt->bytesperline = 0;
+		/* Source size must be aligned to 128 */
+		pfmt->sizeimage = mtk_jpeg_align(pfmt->sizeimage, 128);
+		if (pfmt->sizeimage == 0)
+			pfmt->sizeimage = MTK_JPEG_DEFAULT_SIZEIMAGE;
+		goto end;
+	}
+
+	/* type is MTK_JPEG_FMT_TYPE_CAPTURE */
+	mtk_jpeg_bound_align_image(&pix_mp->width, MTK_JPEG_MIN_WIDTH,
+				   MTK_JPEG_MAX_WIDTH, fmt->h_align,
+				   &pix_mp->height, MTK_JPEG_MIN_HEIGHT,
+				   MTK_JPEG_MAX_HEIGHT, fmt->v_align);
+
+	for (i = 0; i < fmt->colplanes; i++) {
+		struct v4l2_plane_pix_format *pfmt = &pix_mp->plane_fmt[i];
+		u32 stride = pix_mp->width * fmt->h_sample[i] / 4;
+		u32 h = pix_mp->height * fmt->v_sample[i] / 4;
+
+		memset(pfmt->reserved, 0, sizeof(pfmt->reserved));
+		pfmt->bytesperline = stride;
+		pfmt->sizeimage = stride * h;
+	}
+end:
+	v4l2_dbg(2, debug, &jpeg->v4l2_dev, "wxh:%ux%u\n",
+		 pix_mp->width, pix_mp->height);
+	for (i = 0; i < pix_mp->num_planes; i++) {
+		v4l2_dbg(2, debug, &jpeg->v4l2_dev,
+			 "plane[%d] bpl=%u, size=%u\n",
+			 i,
+			 pix_mp->plane_fmt[i].bytesperline,
+			 pix_mp->plane_fmt[i].sizeimage);
+	}
+	return 0;
+}
+
+static int mtk_jpeg_g_fmt_vid_mplane(struct file *file, void *priv,
+				     struct v4l2_format *f)
+{
+	struct vb2_queue *vq;
+	struct mtk_jpeg_q_data *q_data = NULL;
+	struct v4l2_pix_format_mplane *pix_mp = &f->fmt.pix_mp;
+	struct mtk_jpeg_ctx *ctx = mtk_jpeg_fh_to_ctx(priv);
+	struct mtk_jpeg_dev *jpeg = ctx->jpeg;
+	int i;
+
+	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
+	if (!vq)
+		return -EINVAL;
+
+	q_data = mtk_jpeg_get_q_data(ctx, f->type);
+
+	memset(pix_mp->reserved, 0, sizeof(pix_mp->reserved));
+	pix_mp->width = q_data->w;
+	pix_mp->height = q_data->h;
+	pix_mp->field = V4L2_FIELD_NONE;
+	pix_mp->pixelformat = q_data->fmt->fourcc;
+	pix_mp->num_planes = q_data->fmt->colplanes;
+	pix_mp->colorspace = ctx->colorspace;
+	pix_mp->ycbcr_enc = ctx->ycbcr_enc;
+	pix_mp->xfer_func = ctx->xfer_func;
+	pix_mp->quantization = ctx->quantization;
+
+	v4l2_dbg(1, debug, &jpeg->v4l2_dev, "(%d) g_fmt:%s wxh:%ux%u\n",
+		 f->type, q_data->fmt->name, pix_mp->width, pix_mp->height);
+
+	for (i = 0; i < pix_mp->num_planes; i++) {
+		struct v4l2_plane_pix_format *pfmt = &pix_mp->plane_fmt[i];
+
+		pfmt->bytesperline = q_data->bytesperline[i];
+		pfmt->sizeimage = q_data->sizeimage[i];
+		memset(pfmt->reserved, 0, sizeof(pfmt->reserved));
+
+		v4l2_dbg(1, debug, &jpeg->v4l2_dev,
+			 "plane[%d] bpl=%u, size=%u\n",
+			 i,
+			 pfmt->bytesperline,
+			 pfmt->sizeimage);
+	}
+	return 0;
+}
+
+static int mtk_jpeg_try_fmt_vid_cap_mplane(struct file *file, void *priv,
+					   struct v4l2_format *f)
+{
+	struct mtk_jpeg_ctx *ctx = mtk_jpeg_fh_to_ctx(priv);
+	struct mtk_jpeg_fmt *fmt;
+
+	fmt = mtk_jpeg_find_format(ctx, f->fmt.pix_mp.pixelformat,
+				   MTK_JPEG_FMT_TYPE_CAPTURE);
+	if (!fmt)
+		fmt = ctx->cap_q.fmt;
+
+	v4l2_dbg(2, debug, &ctx->jpeg->v4l2_dev, "(%d) try_fmt:%s\n",
+		 f->type, fmt->name);
+
+	return mtk_jpeg_try_fmt_mplane(f, fmt, ctx, MTK_JPEG_FMT_TYPE_CAPTURE);
+}
+
+static int mtk_jpeg_try_fmt_vid_out_mplane(struct file *file, void *priv,
+					   struct v4l2_format *f)
+{
+	struct mtk_jpeg_ctx *ctx = mtk_jpeg_fh_to_ctx(priv);
+	struct mtk_jpeg_fmt *fmt;
+
+	fmt = mtk_jpeg_find_format(ctx, f->fmt.pix_mp.pixelformat,
+				   MTK_JPEG_FMT_TYPE_OUTPUT);
+	if (!fmt)
+		fmt = ctx->out_q.fmt;
+
+	v4l2_dbg(2, debug, &ctx->jpeg->v4l2_dev, "(%d) try_fmt:%s\n",
+		 f->type, fmt->name);
+
+	return mtk_jpeg_try_fmt_mplane(f, fmt, ctx, MTK_JPEG_FMT_TYPE_OUTPUT);
+}
+
+static int mtk_jpeg_s_fmt_mplane(struct mtk_jpeg_ctx *ctx,
+				 struct v4l2_format *f)
+{
+	struct vb2_queue *vq;
+	struct mtk_jpeg_q_data *q_data = NULL;
+	struct v4l2_pix_format_mplane *pix_mp = &f->fmt.pix_mp;
+	struct mtk_jpeg_dev *jpeg = ctx->jpeg;
+	unsigned int f_type;
+	int i;
+
+	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
+	if (!vq)
+		return -EINVAL;
+
+	q_data = mtk_jpeg_get_q_data(ctx, f->type);
+
+	if (vb2_is_busy(vq)) {
+		v4l2_err(&jpeg->v4l2_dev, "queue busy\n");
+		return -EBUSY;
+	}
+
+	f_type = V4L2_TYPE_IS_OUTPUT(f->type) ?
+			 MTK_JPEG_FMT_TYPE_OUTPUT : MTK_JPEG_FMT_TYPE_CAPTURE;
+
+	q_data->fmt = mtk_jpeg_find_format(ctx, pix_mp->pixelformat, f_type);
+	q_data->w = pix_mp->width;
+	q_data->h = pix_mp->height;
+	ctx->colorspace = pix_mp->colorspace;
+	ctx->ycbcr_enc = pix_mp->ycbcr_enc;
+	ctx->xfer_func = pix_mp->xfer_func;
+	ctx->quantization = pix_mp->quantization;
+
+	v4l2_dbg(1, debug, &jpeg->v4l2_dev, "(%d) s_fmt:%s wxh:%ux%u\n",
+		 f->type, q_data->fmt->name, q_data->w, q_data->h);
+
+	for (i = 0; i < q_data->fmt->colplanes; i++) {
+		q_data->bytesperline[i] = pix_mp->plane_fmt[i].bytesperline;
+		q_data->sizeimage[i] = pix_mp->plane_fmt[i].sizeimage;
+
+		v4l2_dbg(1, debug, &jpeg->v4l2_dev,
+			 "plane[%d] bpl=%u, size=%u\n",
+			 i, q_data->bytesperline[i], q_data->sizeimage[i]);
+	}
+
+	return 0;
+}
+
+static int mtk_jpeg_s_fmt_vid_out_mplane(struct file *file, void *priv,
+					 struct v4l2_format *f)
+{
+	int ret;
+
+	ret = mtk_jpeg_try_fmt_vid_out_mplane(file, priv, f);
+	if (ret)
+		return ret;
+
+	return mtk_jpeg_s_fmt_mplane(mtk_jpeg_fh_to_ctx(priv), f);
+}
+
+static int mtk_jpeg_s_fmt_vid_cap_mplane(struct file *file, void *priv,
+					 struct v4l2_format *f)
+{
+	int ret;
+
+	ret = mtk_jpeg_try_fmt_vid_cap_mplane(file, priv, f);
+	if (ret)
+		return ret;
+
+	return mtk_jpeg_s_fmt_mplane(mtk_jpeg_fh_to_ctx(priv), f);
+}
+
+static void mtk_jpeg_queue_src_chg_event(struct mtk_jpeg_ctx *ctx)
+{
+	static const struct v4l2_event ev_src_ch = {
+		.type = V4L2_EVENT_SOURCE_CHANGE,
+		.u.src_change.changes =
+		V4L2_EVENT_SRC_CH_RESOLUTION,
+	};
+
+	v4l2_event_queue_fh(&ctx->fh, &ev_src_ch);
+}
+
+static int mtk_jpeg_subscribe_event(struct v4l2_fh *fh,
+				    const struct v4l2_event_subscription *sub)
+{
+	switch (sub->type) {
+	case V4L2_EVENT_SOURCE_CHANGE:
+		return v4l2_src_change_event_subscribe(fh, sub);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int mtk_jpeg_g_selection(struct file *file, void *priv,
+				struct v4l2_selection *s)
+{
+	struct mtk_jpeg_ctx *ctx = mtk_jpeg_fh_to_ctx(priv);
+
+	if (s->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+		return -EINVAL;
+
+	switch (s->target) {
+	case V4L2_SEL_TGT_COMPOSE:
+	case V4L2_SEL_TGT_COMPOSE_DEFAULT:
+		s->r.width = ctx->out_q.w;
+		s->r.height = ctx->out_q.h;
+		s->r.left = 0;
+		s->r.top = 0;
+		break;
+	case V4L2_SEL_TGT_COMPOSE_BOUNDS:
+	case V4L2_SEL_TGT_COMPOSE_PADDED:
+		s->r.width = ctx->cap_q.w;
+		s->r.height = ctx->cap_q.h;
+		s->r.left = 0;
+		s->r.top = 0;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int mtk_jpeg_s_selection(struct file *file, void *priv,
+				struct v4l2_selection *s)
+{
+	struct mtk_jpeg_ctx *ctx = mtk_jpeg_fh_to_ctx(priv);
+
+	if (s->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+		return -EINVAL;
+
+	switch (s->target) {
+	case V4L2_SEL_TGT_COMPOSE:
+		s->r.left = 0;
+		s->r.top = 0;
+		s->r.width = ctx->out_q.w;
+		s->r.height = ctx->out_q.h;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int mtk_jpeg_qbuf(struct file *file, void *priv, struct v4l2_buffer *buf)
+{
+	struct v4l2_fh *fh = file->private_data;
+	struct vb2_queue *vq;
+	struct vb2_buffer *vb;
+	struct mtk_jpeg_src_buf *jpeg_src_buf;
+
+	if (buf->type != V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE)
+		goto end;
+
+	vq = v4l2_m2m_get_vq(fh->m2m_ctx, buf->type);
+	vb = vq->bufs[buf->index];
+	jpeg_src_buf = mtk_jpeg_vb2_to_srcbuf(vb);
+	jpeg_src_buf->flags = (buf->m.planes[0].bytesused == 0) ?
+		MTK_JPEG_BUF_FLAGS_LAST_FRAME : MTK_JPEG_BUF_FLAGS_INIT;
+end:
+	return v4l2_m2m_qbuf(file, fh->m2m_ctx, buf);
+}
+
+static const struct v4l2_ioctl_ops mtk_jpeg_ioctl_ops = {
+	.vidioc_querycap                = mtk_jpeg_querycap,
+	.vidioc_enum_fmt_vid_cap_mplane = mtk_jpeg_enum_fmt_vid_cap,
+	.vidioc_enum_fmt_vid_out_mplane = mtk_jpeg_enum_fmt_vid_out,
+	.vidioc_try_fmt_vid_cap_mplane	= mtk_jpeg_try_fmt_vid_cap_mplane,
+	.vidioc_try_fmt_vid_out_mplane	= mtk_jpeg_try_fmt_vid_out_mplane,
+	.vidioc_g_fmt_vid_cap_mplane    = mtk_jpeg_g_fmt_vid_mplane,
+	.vidioc_g_fmt_vid_out_mplane    = mtk_jpeg_g_fmt_vid_mplane,
+	.vidioc_s_fmt_vid_cap_mplane    = mtk_jpeg_s_fmt_vid_cap_mplane,
+	.vidioc_s_fmt_vid_out_mplane    = mtk_jpeg_s_fmt_vid_out_mplane,
+	.vidioc_qbuf                    = mtk_jpeg_qbuf,
+	.vidioc_subscribe_event         = mtk_jpeg_subscribe_event,
+	.vidioc_g_selection		= mtk_jpeg_g_selection,
+	.vidioc_s_selection		= mtk_jpeg_s_selection,
+
+	.vidioc_create_bufs		= v4l2_m2m_ioctl_create_bufs,
+	.vidioc_prepare_buf		= v4l2_m2m_ioctl_prepare_buf,
+	.vidioc_reqbufs                 = v4l2_m2m_ioctl_reqbufs,
+	.vidioc_querybuf                = v4l2_m2m_ioctl_querybuf,
+	.vidioc_dqbuf                   = v4l2_m2m_ioctl_dqbuf,
+	.vidioc_expbuf                  = v4l2_m2m_ioctl_expbuf,
+	.vidioc_streamon                = v4l2_m2m_ioctl_streamon,
+	.vidioc_streamoff               = v4l2_m2m_ioctl_streamoff,
+
+	.vidioc_unsubscribe_event	= v4l2_event_unsubscribe,
+};
+
+static int mtk_jpeg_queue_setup(struct vb2_queue *q,
+				unsigned int *num_buffers,
+				unsigned int *num_planes,
+				unsigned int sizes[],
+				struct device *alloc_ctxs[])
+{
+	struct mtk_jpeg_ctx *ctx = vb2_get_drv_priv(q);
+	struct mtk_jpeg_q_data *q_data = NULL;
+	struct mtk_jpeg_dev *jpeg = ctx->jpeg;
+	int i;
+
+	v4l2_dbg(1, debug, &jpeg->v4l2_dev, "(%d) buf_req count=%u\n",
+		 q->type, *num_buffers);
+
+	q_data = mtk_jpeg_get_q_data(ctx, q->type);
+	if (!q_data)
+		return -EINVAL;
+
+	*num_planes = q_data->fmt->colplanes;
+	for (i = 0; i < q_data->fmt->colplanes; i++) {
+		sizes[i] = q_data->sizeimage[i];
+		v4l2_dbg(1, debug, &jpeg->v4l2_dev, "sizeimage[%d]=%u\n",
+			 i, sizes[i]);
+	}
+
+	return 0;
+}
+
+static int mtk_jpeg_buf_prepare(struct vb2_buffer *vb)
+{
+	struct mtk_jpeg_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
+	struct mtk_jpeg_q_data *q_data = NULL;
+	int i;
+
+	q_data = mtk_jpeg_get_q_data(ctx, vb->vb2_queue->type);
+	if (!q_data)
+		return -EINVAL;
+
+	for (i = 0; i < q_data->fmt->colplanes; i++)
+		vb2_set_plane_payload(vb, i, q_data->sizeimage[i]);
+
+	return 0;
+}
+
+static bool mtk_jpeg_check_resolution_change(struct mtk_jpeg_ctx *ctx,
+					     struct mtk_jpeg_dec_param *param)
+{
+	struct mtk_jpeg_dev *jpeg = ctx->jpeg;
+	struct mtk_jpeg_q_data *q_data;
+
+	q_data = &ctx->out_q;
+	if (q_data->w != param->pic_w || q_data->h != param->pic_h) {
+		v4l2_dbg(1, debug, &jpeg->v4l2_dev, "Picture size change\n");
+		return true;
+	}
+
+	q_data = &ctx->cap_q;
+	if (q_data->fmt != mtk_jpeg_find_format(ctx, param->dst_fourcc,
+						MTK_JPEG_FMT_TYPE_CAPTURE)) {
+		v4l2_dbg(1, debug, &jpeg->v4l2_dev, "format change\n");
+		return true;
+	}
+	return false;
+}
+
+static void mtk_jpeg_set_queue_data(struct mtk_jpeg_ctx *ctx,
+				    struct mtk_jpeg_dec_param *param)
+{
+	struct mtk_jpeg_dev *jpeg = ctx->jpeg;
+	struct mtk_jpeg_q_data *q_data;
+	int i;
+
+	q_data = &ctx->out_q;
+	q_data->w = param->pic_w;
+	q_data->h = param->pic_h;
+
+	q_data = &ctx->cap_q;
+	q_data->w = param->dec_w;
+	q_data->h = param->dec_h;
+	q_data->fmt = mtk_jpeg_find_format(ctx,
+					   param->dst_fourcc,
+					   MTK_JPEG_FMT_TYPE_CAPTURE);
+
+	for (i = 0; i < q_data->fmt->colplanes; i++) {
+		q_data->bytesperline[i] = param->mem_stride[i];
+		q_data->sizeimage[i] = param->comp_size[i];
+	}
+
+	v4l2_dbg(1, debug, &jpeg->v4l2_dev,
+		 "set_parse cap:%s pic(%u, %u), buf(%u, %u)\n",
+		 q_data->fmt->name, param->pic_w, param->pic_h,
+		 param->dec_w, param->dec_h);
+}
+
+static void mtk_jpeg_buf_queue(struct vb2_buffer *vb)
+{
+	struct mtk_jpeg_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
+	struct mtk_jpeg_dec_param *param;
+	struct mtk_jpeg_dev *jpeg = ctx->jpeg;
+	struct mtk_jpeg_src_buf *jpeg_src_buf;
+	bool header_valid;
+
+	v4l2_dbg(2, debug, &jpeg->v4l2_dev, "(%d) buf_q id=%d, vb=%p",
+		 vb->vb2_queue->type, vb->index, vb);
+
+	if (vb->vb2_queue->type != V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE)
+		goto end;
+
+	jpeg_src_buf = mtk_jpeg_vb2_to_srcbuf(vb);
+	param = &jpeg_src_buf->dec_param;
+	memset(param, 0, sizeof(*param));
+
+	if (jpeg_src_buf->flags & MTK_JPEG_BUF_FLAGS_LAST_FRAME) {
+		v4l2_dbg(1, debug, &jpeg->v4l2_dev, "Got eos");
+		goto end;
+	}
+	header_valid = mtk_jpeg_parse(param, (u8 *)vb2_plane_vaddr(vb, 0),
+				      vb2_get_plane_payload(vb, 0));
+	if (!header_valid) {
+		v4l2_err(&jpeg->v4l2_dev, "Header invalid.\n");
+		vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
+		return;
+	}
+
+	if (ctx->state == MTK_JPEG_INIT) {
+		mtk_jpeg_queue_src_chg_event(ctx);
+		mtk_jpeg_set_queue_data(ctx, param);
+		ctx->state = MTK_JPEG_RUNNING;
+	}
+end:
+	v4l2_m2m_buf_queue(ctx->fh.m2m_ctx, to_vb2_v4l2_buffer(vb));
+}
+
+static void *mtk_jpeg_buf_remove(struct mtk_jpeg_ctx *ctx,
+				 enum v4l2_buf_type type)
+{
+	if (V4L2_TYPE_IS_OUTPUT(type))
+		return v4l2_m2m_src_buf_remove(ctx->fh.m2m_ctx);
+	else
+		return v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx);
+}
+
+static int mtk_jpeg_start_streaming(struct vb2_queue *q, unsigned int count)
+{
+	struct mtk_jpeg_ctx *ctx = vb2_get_drv_priv(q);
+	int ret = 0;
+
+	ret = pm_runtime_get_sync(ctx->jpeg->dev);
+

If start_streaming returns an error, then you must call
v4l2_m2m_buf_done(to_vb2_v4l2_buffer(vb), VB2_BUF_STATE_QUEUED) for all
buffers. Similar to what happens in stop_streaming, but with a different VB2_BUF_STATE.

+	return ret > 0 ? 0 : ret;
+}
+
+static void mtk_jpeg_stop_streaming(struct vb2_queue *q)
+{
+	struct mtk_jpeg_ctx *ctx = vb2_get_drv_priv(q);
+	struct vb2_buffer *vb;
+
+	/*
+	 * STREAMOFF is an acknowledgment for source change event.
+	 * Before STREAMOFF, we still have to return the old resolution and
+	 * subsampling. Update capture queue when the stream is off.
+	 */
+	if (ctx->state == MTK_JPEG_SOURCE_CHANGE &&
+	    !V4L2_TYPE_IS_OUTPUT(q->type)) {
+		struct mtk_jpeg_src_buf *src_buf;
+
+		vb = v4l2_m2m_next_src_buf(ctx->fh.m2m_ctx);
+		src_buf = mtk_jpeg_vb2_to_srcbuf(vb);
+		mtk_jpeg_set_queue_data(ctx, &src_buf->dec_param);
+		ctx->state = MTK_JPEG_RUNNING;
+	} else if (V4L2_TYPE_IS_OUTPUT(q->type)) {
+		ctx->state = MTK_JPEG_INIT;
+	}
+
+	vb = mtk_jpeg_buf_remove(ctx, q->type);
+	while (vb) {
+		v4l2_m2m_buf_done(to_vb2_v4l2_buffer(vb), VB2_BUF_STATE_ERROR);
+		vb = mtk_jpeg_buf_remove(ctx, q->type);
+	}
+
+	pm_runtime_put_sync(ctx->jpeg->dev);
+}
+
+static struct vb2_ops mtk_jpeg_qops = {
+	.queue_setup        = mtk_jpeg_queue_setup,
+	.buf_prepare        = mtk_jpeg_buf_prepare,
+	.buf_queue          = mtk_jpeg_buf_queue,
+	.wait_prepare       = vb2_ops_wait_prepare,
+	.wait_finish        = vb2_ops_wait_finish,
+	.start_streaming    = mtk_jpeg_start_streaming,
+	.stop_streaming     = mtk_jpeg_stop_streaming,
+};
+
+static void mtk_jpeg_set_dec_src(struct mtk_jpeg_ctx *ctx,
+				 struct vb2_buffer *src_buf,
+				 struct mtk_jpeg_bs *bs)
+{
+	bs->str_addr = vb2_dma_contig_plane_dma_addr(src_buf, 0);
+	bs->end_addr = bs->str_addr +
+			 mtk_jpeg_align(vb2_get_plane_payload(src_buf, 0), 16);
+	bs->size = mtk_jpeg_align(vb2_plane_size(src_buf, 0), 128);
+}
+
+static int mtk_jpeg_set_dec_dst(struct mtk_jpeg_ctx *ctx,
+				struct mtk_jpeg_dec_param *param,
+				struct vb2_buffer *dst_buf,
+				struct mtk_jpeg_fb *fb)
+{
+	int i;
+
+	if (param->comp_num != dst_buf->num_planes) {
+		dev_err(ctx->jpeg->dev, "plane number mismatch (%u != %u)\n",
+			param->comp_num, dst_buf->num_planes);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < dst_buf->num_planes; i++) {
+		if (vb2_plane_size(dst_buf, i) < param->comp_size[i]) {
+			dev_err(ctx->jpeg->dev,
+				"buffer size is underflow (%lu < %u)\n",
+				vb2_plane_size(dst_buf, 0),
+				param->comp_size[i]);
+			return -EINVAL;
+		}
+		fb->plane_addr[i] = vb2_dma_contig_plane_dma_addr(dst_buf, i);
+	}
+
+	return 0;
+}
+
+static void mtk_jpeg_device_run(void *priv)
+{
+	struct mtk_jpeg_ctx *ctx = priv;
+	struct mtk_jpeg_dev *jpeg = ctx->jpeg;
+	struct vb2_buffer *src_buf, *dst_buf;
+	enum vb2_buffer_state buf_state = VB2_BUF_STATE_ERROR;
+	unsigned long flags;
+	struct mtk_jpeg_src_buf *jpeg_src_buf;
+	struct mtk_jpeg_bs bs;
+	struct mtk_jpeg_fb fb;
+	int i;
+
+	src_buf = v4l2_m2m_next_src_buf(ctx->fh.m2m_ctx);
+	dst_buf = v4l2_m2m_next_dst_buf(ctx->fh.m2m_ctx);
+	jpeg_src_buf = mtk_jpeg_vb2_to_srcbuf(src_buf);
+
+	if (jpeg_src_buf->flags & MTK_JPEG_BUF_FLAGS_LAST_FRAME) {
+		for (i = 0; i < dst_buf->num_planes; i++)
+			vb2_set_plane_payload(dst_buf, i, 0);
+		buf_state = VB2_BUF_STATE_DONE;
+		goto dec_end;
+	}
+
+	if (mtk_jpeg_check_resolution_change(ctx, &jpeg_src_buf->dec_param)) {
+		mtk_jpeg_queue_src_chg_event(ctx);
+		ctx->state = MTK_JPEG_SOURCE_CHANGE;
+		v4l2_m2m_job_finish(jpeg->m2m_dev, ctx->fh.m2m_ctx);
+		return;
+	}
+
+	mtk_jpeg_set_dec_src(ctx, src_buf, &bs);
+	if (mtk_jpeg_set_dec_dst(ctx, &jpeg_src_buf->dec_param, dst_buf, &fb))
+		goto dec_end;
+
+	spin_lock_irqsave(&jpeg->hw_lock, flags);
+	mtk_jpeg_dec_reset(jpeg->dec_reg_base);
+	mtk_jpeg_dec_set_config(jpeg->dec_reg_base,
+				&jpeg_src_buf->dec_param, &bs, &fb);
+
+	mtk_jpeg_dec_start(jpeg->dec_reg_base);
+	spin_unlock_irqrestore(&jpeg->hw_lock, flags);
+	return;
+
+dec_end:
+	v4l2_m2m_src_buf_remove(ctx->fh.m2m_ctx);
+	v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx);
+	v4l2_m2m_buf_done(to_vb2_v4l2_buffer(src_buf), buf_state);
+	v4l2_m2m_buf_done(to_vb2_v4l2_buffer(dst_buf), buf_state);
+	v4l2_m2m_job_finish(jpeg->m2m_dev, ctx->fh.m2m_ctx);
+}
+
+static int mtk_jpeg_job_ready(void *priv)
+{
+	struct mtk_jpeg_ctx *ctx = priv;
+
+	return (ctx->state == MTK_JPEG_RUNNING) ? 1 : 0;
+}
+
+static void mtk_jpeg_job_abort(void *priv)
+{
+	struct mtk_jpeg_ctx *ctx = priv;
+	struct mtk_jpeg_dev *jpeg = ctx->jpeg;
+	struct vb2_buffer *src_buf, *dst_buf;
+
+	src_buf = v4l2_m2m_src_buf_remove(ctx->fh.m2m_ctx);
+	dst_buf = v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx);
+	v4l2_m2m_buf_done(to_vb2_v4l2_buffer(src_buf), VB2_BUF_STATE_ERROR);
+	v4l2_m2m_buf_done(to_vb2_v4l2_buffer(dst_buf), VB2_BUF_STATE_ERROR);
+	v4l2_m2m_job_finish(jpeg->m2m_dev, ctx->fh.m2m_ctx);
+}
+
+static struct v4l2_m2m_ops mtk_jpeg_m2m_ops = {
+	.device_run = mtk_jpeg_device_run,
+	.job_ready  = mtk_jpeg_job_ready,
+	.job_abort  = mtk_jpeg_job_abort,
+};
+
+static int mtk_jpeg_queue_init(void *priv, struct vb2_queue *src_vq,
+			       struct vb2_queue *dst_vq)
+{
+	struct mtk_jpeg_ctx *ctx = priv;
+	int ret;
+
+	src_vq->type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+	src_vq->io_modes = VB2_DMABUF | VB2_MMAP | VB2_USERPTR;

I would drop USERPTR, it really makes little sense for dma_contig.

+	src_vq->drv_priv = ctx;
+	src_vq->buf_struct_size = sizeof(struct mtk_jpeg_src_buf);
+	src_vq->ops = &mtk_jpeg_qops;
+	src_vq->mem_ops = &vb2_dma_contig_memops;
+	src_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
+	src_vq->lock = &ctx->jpeg->lock;
+	src_vq->dev = ctx->jpeg->dev;
+	ret = vb2_queue_init(src_vq);
+	if (ret)
+		return ret;
+
+	dst_vq->type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+	dst_vq->io_modes = VB2_DMABUF | VB2_MMAP | VB2_USERPTR;

Ditto.

No need for 'else' here since the previous 'if' always returns if true.

+
+	return MTK_JPEG_DEC_RESULT_ERROR_UNKNOWN;
+}
+
+void mtk_jpeg_dec_start(void __iomem *base)
+{
+	writel(0, base + JPGDEC_REG_TRIG);
+}
+
+static void mtk_jpeg_dec_soft_reset(void __iomem *base)
+{
+	writel(0x0000FFFF, base + JPGDEC_REG_INTERRUPT_STATUS);
+	writel(0x00, base + JPGDEC_REG_RESET);
+	writel(0x01, base + JPGDEC_REG_RESET);
+}
+
+static void mtk_jpeg_dec_hard_reset(void __iomem *base)
+{
+	writel(0x00, base + JPGDEC_REG_RESET);
+	writel(0x10, base + JPGDEC_REG_RESET);
+}
+
+void mtk_jpeg_dec_reset(void __iomem *base)
+{
+	mtk_jpeg_dec_soft_reset(base);
+	mtk_jpeg_dec_hard_reset(base);
+}
+
+static void mtk_jpeg_dec_set_brz_factor(void __iomem *base, u8 yscale_w,
+					u8 yscale_h, u8 uvscale_w, u8 uvscale_h)
+{
+	u32 val;
+
+	val = (uvscale_h << 12) | (uvscale_w << 8) |
+	      (yscale_h << 4) | yscale_w;
+	writel(val, base + JPGDEC_REG_BRZ_FACTOR);
+}
+
+static void mtk_jpeg_dec_set_dst_bank0(void __iomem *base, u32 addr_y,
+				       u32 addr_u, u32 addr_v)
+{
+	mtk_jpeg_verify_align(addr_y, 16, JPGDEC_REG_DEST_ADDR0_Y);
+	writel(addr_y, base + JPGDEC_REG_DEST_ADDR0_Y);
+	mtk_jpeg_verify_align(addr_u, 16, JPGDEC_REG_DEST_ADDR0_U);
+	writel(addr_u, base + JPGDEC_REG_DEST_ADDR0_U);
+	mtk_jpeg_verify_align(addr_v, 16, JPGDEC_REG_DEST_ADDR0_V);
+	writel(addr_v, base + JPGDEC_REG_DEST_ADDR0_V);
+}
+
+static void mtk_jpeg_dec_set_dst_bank1(void __iomem *base, u32 addr_y,
+				       u32 addr_u, u32 addr_v)
+{
+	writel(addr_y, base + JPGDEC_REG_DEST_ADDR1_Y);
+	writel(addr_u, base + JPGDEC_REG_DEST_ADDR1_U);
+	writel(addr_v, base + JPGDEC_REG_DEST_ADDR1_V);
+}
+
+static void mtk_jpeg_dec_set_mem_stride(void __iomem *base, u32 stride_y,
+					u32 stride_uv)
+{
+	writel((stride_y & 0xFFFF), base + JPGDEC_REG_STRIDE_Y);
+	writel((stride_uv & 0xFFFF), base + JPGDEC_REG_STRIDE_UV);
+}
+
+static void mtk_jpeg_dec_set_img_stride(void __iomem *base, u32 stride_y,
+					u32 stride_uv)
+{
+	writel((stride_y & 0xFFFF), base + JPGDEC_REG_IMG_STRIDE_Y);
+	writel((stride_uv & 0xFFFF), base + JPGDEC_REG_IMG_STRIDE_UV);
+}
+
+static void mtk_jpeg_dec_set_pause_mcu_idx(void __iomem *base, u32 idx)
+{
+	writel(idx & 0x0003FFFFFF, base + JPGDEC_REG_PAUSE_MCU_NUM);
+}
+
+static void mtk_jpeg_dec_set_dec_mode(void __iomem *base, u32 mode)
+{
+	writel(mode & 0x03, base + JPGDEC_REG_OPERATION_MODE);
+}
+
+static void mtk_jpeg_dec_set_bs_write_ptr(void __iomem *base, u32 ptr)
+{
+	mtk_jpeg_verify_align(ptr, 16, JPGDEC_REG_FILE_BRP);
+	writel(ptr, base + JPGDEC_REG_FILE_BRP);
+}
+
+static void mtk_jpeg_dec_set_bs_info(void __iomem *base, u32 addr, u32 size)
+{
+	mtk_jpeg_verify_align(addr, 16, JPGDEC_REG_FILE_ADDR);
+	mtk_jpeg_verify_align(size, 128, JPGDEC_REG_FILE_TOTAL_SIZE);
+	writel(addr, base + JPGDEC_REG_FILE_ADDR);
+	writel(size, base + JPGDEC_REG_FILE_TOTAL_SIZE);
+}
+
+static void mtk_jpeg_dec_set_comp_id(void __iomem *base, u32 id_y, u32 id_u,
+				     u32 id_v)
+{
+	u32 val;
+
+	val = ((id_y & 0x00FF) << 24) | ((id_u & 0x00FF) << 16) |
+	      ((id_v & 0x00FF) << 8);
+	writel(val, base + JPGDEC_REG_COMP_ID);
+}
+
+static void mtk_jpeg_dec_set_total_mcu(void __iomem *base, u32 num)
+{
+	writel(num - 1, base + JPGDEC_REG_TOTAL_MCU_NUM);
+}
+
+static void mtk_jpeg_dec_set_comp0_du(void __iomem *base, u32 num)
+{
+	writel(num - 1, base + JPGDEC_REG_COMP0_DATA_UNIT_NUM);
+}
+
+static void mtk_jpeg_dec_set_du_membership(void __iomem *base, u32 member,
+					   u32 gmc, u32 isgray)
+{
+	if (isgray)
+		member = 0x3FFFFFFC;
+	member |= (isgray << 31) | (gmc << 30);
+	writel(member, base + JPGDEC_REG_DU_CTRL);
+}
+
+static void mtk_jpeg_dec_set_q_table(void __iomem *base, u32 id0, u32 id1,
+				     u32 id2)
+{
+	u32 val;
+
+	val = ((id0 & 0x0f) << 8) | ((id1 & 0x0f) << 4) | ((id2 & 0x0f) << 0);
+	writel(val, base + JPGDEC_REG_QT_ID);
+}
+
+static void mtk_jpeg_dec_set_dma_group(void __iomem *base, u32 mcu_group,
+				       u32 group_num, u32 last_mcu)
+{
+	u32 val;
+
+	val = (((mcu_group - 1) & 0x00FF) << 16) |
+	      (((group_num - 1) & 0x007F) << 8) |
+	      ((last_mcu - 1) & 0x00FF);
+	writel(val, base + JPGDEC_REG_WDMA_CTRL);
+}
+
+static void mtk_jpeg_dec_set_sampling_factor(void __iomem *base, u32 comp_num,
+					     u32 y_w, u32 y_h, u32 u_w,
+					     u32 u_h, u32 v_w, u32 v_h)
+{
+	u32 val;
+	u32 y_wh = (MTK_JPEG_DUNUM_MASK(y_w) << 2) | MTK_JPEG_DUNUM_MASK(y_h);
+	u32 u_wh = (MTK_JPEG_DUNUM_MASK(u_w) << 2) | MTK_JPEG_DUNUM_MASK(u_h);
+	u32 v_wh = (MTK_JPEG_DUNUM_MASK(v_w) << 2) | MTK_JPEG_DUNUM_MASK(v_h);
+
+	if (comp_num == 1)
+		val = 0;
+	else
+		val = (y_wh << 8) | (u_wh << 4) | v_wh;
+	writel(val, base + JPGDEC_REG_DU_NUM);
+}
+
+void mtk_jpeg_dec_set_config(void __iomem *base,
+			     struct mtk_jpeg_dec_param *config,
+			     struct mtk_jpeg_bs *bs,
+			     struct mtk_jpeg_fb *fb)
+{
+	mtk_jpeg_dec_set_brz_factor(base, 0, 0, config->uv_brz_w, 0);
+	mtk_jpeg_dec_set_dec_mode(base, 0);
+	mtk_jpeg_dec_set_comp0_du(base, config->unit_num);
+	mtk_jpeg_dec_set_total_mcu(base, config->total_mcu);
+	mtk_jpeg_dec_set_bs_info(base, bs->str_addr, bs->size);
+	mtk_jpeg_dec_set_bs_write_ptr(base, bs->end_addr);
+	mtk_jpeg_dec_set_du_membership(base, config->membership, 1,
+				       (config->comp_num == 1) ? 1 : 0);
+	mtk_jpeg_dec_set_comp_id(base, config->comp_id[0], config->comp_id[1],
+				 config->comp_id[2]);
+	mtk_jpeg_dec_set_q_table(base, config->qtbl_num[0],
+				 config->qtbl_num[1], config->qtbl_num[2]);
+	mtk_jpeg_dec_set_sampling_factor(base, config->comp_num,
+					 config->sampling_w[0],
+					 config->sampling_h[0],
+					 config->sampling_w[1],
+					 config->sampling_h[1],
+					 config->sampling_w[2],
+					 config->sampling_h[2]);
+	mtk_jpeg_dec_set_mem_stride(base, config->mem_stride[0],
+				    config->mem_stride[1]);
+	mtk_jpeg_dec_set_img_stride(base, config->img_stride[0],
+				    config->img_stride[1]);
+	mtk_jpeg_dec_set_dst_bank0(base, fb->plane_addr[0],
+				   fb->plane_addr[1], fb->plane_addr[2]);
+	mtk_jpeg_dec_set_dst_bank1(base, 0, 0, 0);
+	mtk_jpeg_dec_set_dma_group(base, config->dma_mcu, config->dma_group,
+				   config->dma_last_mcu);
+	mtk_jpeg_dec_set_pause_mcu_idx(base, config->total_mcu);
+}

Regards,

	Hans