Subject: Re: [PATCH v2 1/3] media: V3s: Add support for Allwinner CSI.
To: Yong Deng <yong.deng@magewell.com>, maxime.ripard@free-electrons.com
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>,
        Rob Herring <robh+dt@kernel.org>, Mark Rutland <mark.rutland@arm.com>,
        Chen-Yu Tsai <wens@csie.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "David S. Miller" <davem@davemloft.net>, Arnd Bergmann <arnd@arndb.de>,
        Hugues Fruchet <hugues.fruchet@st.com>,
        Yannick Fertre <yannick.fertre@st.com>,
        Philipp Zabel <p.zabel@pengutronix.de>, Benoit Parrot <bparrot@ti.com>,
        Benjamin Gaignard <benjamin.gaignard@linaro.org>,
        Jean-Christophe Trotin <jean-christophe.trotin@st.com>,
        Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com>,
        Minghsiu Tsai <minghsiu.tsai@mediatek.com>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Robert Jarzmik <robert.jarzmik@free.fr>, linux-media@vger.kernel.org,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com
References: <1501131697-1359-1-git-send-email-yong.deng@magewell.com>
 <1501131697-1359-2-git-send-email-yong.deng@magewell.com>
From: Hans Verkuil <hverkuil@xs4all.nl>
Message-ID: <5082b6d6-29a7-f101-8cba-13fce8983c89@xs4all.nl>
Date: Mon, 21 Aug 2017 16:37:41 +0200
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Hi Yong,

First two high-level comments before I start the review:

1) Can you provide the v4l2-compliance output? I can't merge this unless I
   see that it passes the compliance tests. Make sure you compile from the git
   repo (https://git.linuxtv.org/v4l-utils.git/) so you are using the latest
   version of the compliance test. Test with just 'v4l2-compliance' and also
   with the -s option (to test streaming) and with the -f option (to test all
   the various pixel formats).

2) I see you support interlaced formats. Did you actually test that? Interlaced
   is tricky and you shouldn't add support for it unless you know it works and
   that it passes the 'v4l2-compliance -s' test.

On 07/27/2017 07:01 AM, Yong Deng wrote:
> Allwinner V3s SoC have two CSI module. CSI0 is used for MIPI interface
> and CSI1 is used for parallel interface. This is not documented in
> datasheet but by testing and guess.
> 
> This patch implement a v4l2 framework driver for it.
> 
> Currently, the driver only support the parallel interface. MIPI-CSI2,
> ISP's support are not included in this patch.
> 
> Signed-off-by: Yong Deng <yong.deng@magewell.com>
> ---
>  drivers/media/platform/Kconfig                   |   1 +
>  drivers/media/platform/Makefile                  |   2 +
>  drivers/media/platform/sun6i-csi/Kconfig         |   9 +
>  drivers/media/platform/sun6i-csi/Makefile        |   3 +
>  drivers/media/platform/sun6i-csi/sun6i_csi.c     | 545 +++++++++++++++
>  drivers/media/platform/sun6i-csi/sun6i_csi.h     | 203 ++++++
>  drivers/media/platform/sun6i-csi/sun6i_csi_v3s.c | 827 +++++++++++++++++++++++
>  drivers/media/platform/sun6i-csi/sun6i_csi_v3s.h | 206 ++++++
>  drivers/media/platform/sun6i-csi/sun6i_video.c   | 663 ++++++++++++++++++
>  drivers/media/platform/sun6i-csi/sun6i_video.h   |  61 ++
>  10 files changed, 2520 insertions(+)
>  create mode 100644 drivers/media/platform/sun6i-csi/Kconfig
>  create mode 100644 drivers/media/platform/sun6i-csi/Makefile
>  create mode 100644 drivers/media/platform/sun6i-csi/sun6i_csi.c
>  create mode 100644 drivers/media/platform/sun6i-csi/sun6i_csi.h
>  create mode 100644 drivers/media/platform/sun6i-csi/sun6i_csi_v3s.c
>  create mode 100644 drivers/media/platform/sun6i-csi/sun6i_csi_v3s.h
>  create mode 100644 drivers/media/platform/sun6i-csi/sun6i_video.c
>  create mode 100644 drivers/media/platform/sun6i-csi/sun6i_video.h
> 

<snip>

> diff --git a/drivers/media/platform/sun6i-csi/sun6i_video.c b/drivers/media/platform/sun6i-csi/sun6i_video.c
> new file mode 100644
> index 0000000..0c5dbd2
> --- /dev/null
> +++ b/drivers/media/platform/sun6i-csi/sun6i_video.c
> @@ -0,0 +1,663 @@
> +/*
> + * Copyright (c) 2017 Magewell Electronics Co., Ltd. (Nanjing).
> + * All rights reserved.
> + * Author: Yong Deng <yong.deng@magewell.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/of.h>
> +
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-ioctl.h>
> +#include <media/v4l2-mc.h>
> +#include <media/videobuf2-dma-contig.h>
> +#include <media/videobuf2-v4l2.h>
> +
> +#include "sun6i_csi.h"
> +#include "sun6i_video.h"
> +
> +struct sun6i_csi_buffer {
> +	struct vb2_v4l2_buffer		vb;
> +	struct list_head		list;
> +
> +	dma_addr_t			dma_addr;
> +};
> +
> +static struct sun6i_csi_format *
> +find_format_by_fourcc(struct sun6i_video *video, unsigned int fourcc)
> +{
> +	unsigned int num_formats = video->num_formats;
> +	struct sun6i_csi_format *fmt;
> +	unsigned int i;
> +
> +	for (i = 0; i < num_formats; i++) {
> +		fmt = &video->formats[i];
> +		if (fmt->fourcc == fourcc)
> +			return fmt;
> +	}
> +
> +	return NULL;
> +}
> +
> +static struct v4l2_subdev *
> +sun6i_video_remote_subdev(struct sun6i_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);
> +}
> +
> +static int sun6i_video_queue_setup(struct vb2_queue *vq,
> +				 unsigned int *nbuffers, unsigned int *nplanes,
> +				 unsigned int sizes[],
> +				 struct device *alloc_devs[])
> +{
> +	struct sun6i_video *video = vb2_get_drv_priv(vq);
> +	unsigned int size = video->fmt.fmt.pix.sizeimage;
> +
> +	if (*nplanes)
> +		return sizes[0] < size ? -EINVAL : 0;
> +
> +	*nplanes = 1;
> +	sizes[0] = size;
> +
> +	return 0;
> +}
> +
> +static int sun6i_video_buffer_prepare(struct vb2_buffer *vb)
> +{
> +	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
> +	struct sun6i_csi_buffer *buf =
> +			container_of(vbuf, struct sun6i_csi_buffer, vb);
> +	struct sun6i_video *video = vb2_get_drv_priv(vb->vb2_queue);
> +	unsigned long size = video->fmt.fmt.pix.sizeimage;
> +
> +	if (vb2_plane_size(vb, 0) < size) {
> +		v4l2_err(video->vdev.v4l2_dev, "buffer too small (%lu < %lu)\n",
> +			 vb2_plane_size(vb, 0), size);
> +		return -EINVAL;
> +	}
> +
> +	vb2_set_plane_payload(vb, 0, size);
> +
> +	buf->dma_addr = vb2_dma_contig_plane_dma_addr(vb, 0);
> +
> +	vbuf->field = video->fmt.fmt.pix.field;
> +
> +	return 0;
> +}
> +
> +static int sun6i_pipeline_set_stream(struct sun6i_video *video, bool enable)
> +{
> +	struct media_entity *entity;
> +	struct media_pad *pad;
> +	struct v4l2_subdev *subdev;
> +	int ret;
> +
> +	entity = &video->vdev.entity;
> +	while (1) {
> +		pad = &entity->pads[0];
> +		if (!(pad->flags & MEDIA_PAD_FL_SINK))
> +			break;
> +
> +		pad = media_entity_remote_pad(pad);
> +		if (!pad || !is_media_entity_v4l2_subdev(pad->entity))
> +			break;
> +
> +		entity = pad->entity;
> +		subdev = media_entity_to_v4l2_subdev(entity);
> +
> +		ret = v4l2_subdev_call(subdev, video, s_stream, enable);
> +		if (enable && ret < 0 && ret != -ENOIOCTLCMD)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int sun6i_video_start_streaming(struct vb2_queue *vq, unsigned int count)
> +{
> +	struct sun6i_video *video = vb2_get_drv_priv(vq);
> +	struct sun6i_csi_buffer *buf;
> +	struct sun6i_csi_config config;
> +	unsigned long flags;
> +	int ret;
> +
> +	video->sequence = 0;
> +
> +	ret = media_pipeline_start(&video->vdev.entity, &video->vdev.pipe);
> +	if (ret < 0)
> +		goto err_start_pipeline;
> +
> +	ret = sun6i_pipeline_set_stream(video, true);
> +	if (ret < 0)
> +		goto err_start_stream;
> +
> +	config.pixelformat = video->fmt.fmt.pix.pixelformat;
> +	config.code = video->current_fmt->mbus_code;
> +	config.field = video->fmt.fmt.pix.field;
> +	config.width = video->fmt.fmt.pix.width;
> +	config.height = video->fmt.fmt.pix.height;
> +
> +	ret = sun6i_csi_update_config(video->csi, &config);
> +	if (ret < 0)
> +		goto err_update_config;
> +
> +	spin_lock_irqsave(&video->dma_queue_lock, flags);
> +	video->cur_frm = list_first_entry(&video->dma_queue,
> +					  struct sun6i_csi_buffer, list);
> +	list_del(&video->cur_frm->list);
> +	spin_unlock_irqrestore(&video->dma_queue_lock, flags);
> +
> +	ret = sun6i_csi_update_buf_addr(video->csi, video->cur_frm->dma_addr);
> +	if (ret < 0)
> +		goto err_update_addr;
> +
> +	ret = sun6i_csi_set_stream(video->csi, true);
> +	if (ret < 0)
> +		goto err_csi_stream;
> +
> +	return 0;
> +
> +err_csi_stream:
> +err_update_addr:
> +err_update_config:
> +	sun6i_pipeline_set_stream(video, false);
> +err_start_stream:
> +	media_pipeline_stop(&video->vdev.entity);
> +err_start_pipeline:
> +	spin_lock_irqsave(&video->dma_queue_lock, flags);
> +	list_for_each_entry(buf, &video->dma_queue, list)
> +		vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_QUEUED);
> +	INIT_LIST_HEAD(&video->dma_queue);
> +	spin_unlock_irqrestore(&video->dma_queue_lock, flags);
> +
> +	return ret;
> +}
> +
> +static void sun6i_video_stop_streaming(struct vb2_queue *vq)
> +{
> +	struct sun6i_video *video = vb2_get_drv_priv(vq);
> +	unsigned long flags;
> +	struct sun6i_csi_buffer *buf;
> +
> +	sun6i_pipeline_set_stream(video, false);
> +
> +	sun6i_csi_set_stream(video->csi, false);
> +
> +	media_pipeline_stop(&video->vdev.entity);
> +
> +	/* Release all active buffers */
> +	spin_lock_irqsave(&video->dma_queue_lock, flags);
> +	if (unlikely(video->cur_frm)) {
> +		vb2_buffer_done(&video->cur_frm->vb.vb2_buf,
> +				VB2_BUF_STATE_ERROR);
> +		video->cur_frm = NULL;
> +	}
> +	list_for_each_entry(buf, &video->dma_queue, list)
> +		vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
> +	INIT_LIST_HEAD(&video->dma_queue);
> +	spin_unlock_irqrestore(&video->dma_queue_lock, flags);
> +}
> +
> +static void sun6i_video_buffer_queue(struct vb2_buffer *vb)
> +{
> +	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
> +	struct sun6i_csi_buffer *buf =
> +			container_of(vbuf, struct sun6i_csi_buffer, vb);
> +	struct sun6i_video *video = vb2_get_drv_priv(vb->vb2_queue);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&video->dma_queue_lock, flags);
> +	if (!video->cur_frm && list_empty(&video->dma_queue) &&
> +		vb2_is_streaming(vb->vb2_queue)) {
> +		video->cur_frm = buf;
> +		sun6i_csi_update_buf_addr(video->csi, video->cur_frm->dma_addr);
> +		sun6i_csi_set_stream(video->csi, 1);
> +	} else
> +		list_add_tail(&buf->list, &video->dma_queue);
> +	spin_unlock_irqrestore(&video->dma_queue_lock, flags);
> +}
> +
> +void sun6i_video_frame_done(struct sun6i_video *video)
> +{
> +	spin_lock(&video->dma_queue_lock);
> +
> +	if (video->cur_frm) {
> +		struct vb2_v4l2_buffer *vbuf = &video->cur_frm->vb;
> +		struct vb2_buffer *vb = &vbuf->vb2_buf;
> +
> +		vb->timestamp = ktime_get_ns();
> +		vbuf->sequence = video->sequence++;
> +		vb2_buffer_done(vb, VB2_BUF_STATE_DONE);
> +		video->cur_frm = NULL;
> +	}
> +
> +	if (!list_empty(&video->dma_queue)
> +	    && vb2_is_streaming(&video->vb2_vidq)) {
> +		video->cur_frm = list_first_entry(&video->dma_queue,
> +				struct sun6i_csi_buffer, list);
> +		list_del(&video->cur_frm->list);
> +		sun6i_csi_update_buf_addr(video->csi, video->cur_frm->dma_addr);
> +	} else
> +		sun6i_csi_set_stream(video->csi, 0);
> +
> +	spin_unlock(&video->dma_queue_lock);
> +}
> +
> +static struct vb2_ops sun6i_csi_vb2_ops = {
> +	.queue_setup		= sun6i_video_queue_setup,
> +	.wait_prepare		= vb2_ops_wait_prepare,
> +	.wait_finish		= vb2_ops_wait_finish,
> +	.buf_prepare		= sun6i_video_buffer_prepare,
> +	.start_streaming	= sun6i_video_start_streaming,
> +	.stop_streaming		= sun6i_video_stop_streaming,
> +	.buf_queue		= sun6i_video_buffer_queue,
> +};
> +
> +static int vidioc_querycap(struct file *file, void *priv,
> +				struct v4l2_capability *cap)
> +{
> +	struct sun6i_video *video = video_drvdata(file);
> +
> +	strlcpy(cap->driver, "sun6i-video", sizeof(cap->driver));
> +	strlcpy(cap->card, video->vdev.name, sizeof(cap->card));
> +	snprintf(cap->bus_info, sizeof(cap->bus_info), "platform:%s",
> +		 video->csi->dev->of_node->name);
> +
> +	return 0;
> +}
> +
> +static int vidioc_enum_fmt_vid_cap(struct file *file, void *priv,
> +				   struct v4l2_fmtdesc *f)
> +{
> +	struct sun6i_video *video = video_drvdata(file);
> +	u32 index = f->index;
> +
> +	if (index >= video->num_formats)
> +		return -EINVAL;
> +
> +	f->pixelformat = video->formats[index].fourcc;
> +
> +	return 0;
> +}
> +
> +static int vidioc_g_fmt_vid_cap(struct file *file, void *priv,
> +				struct v4l2_format *fmt)
> +{
> +	struct sun6i_video *video = video_drvdata(file);
> +
> +	*fmt = video->fmt;
> +
> +	return 0;
> +}
> +
> +static int sun6i_video_try_fmt(struct sun6i_video *video, struct v4l2_format *f,
> +			       struct sun6i_csi_format **current_fmt)
> +{
> +	struct sun6i_csi_format *csi_fmt;
> +	struct v4l2_pix_format *pixfmt = &f->fmt.pix;
> +	struct v4l2_subdev_format format;
> +	struct v4l2_subdev *subdev;
> +	u32 pad;
> +	int ret;
> +
> +	subdev = sun6i_video_remote_subdev(video, &pad);
> +	if (subdev == NULL)
> +		return -ENXIO;
> +
> +	csi_fmt = find_format_by_fourcc(video, pixfmt->pixelformat);
> +	if (csi_fmt == NULL)
> +		return -EINVAL;
> +
> +	format.pad = pad;
> +	format.which = V4L2_SUBDEV_FORMAT_TRY;
> +	v4l2_fill_mbus_format(&format.format, pixfmt, csi_fmt->mbus_code);
> +	ret = v4l2_subdev_call(subdev, pad, get_fmt, NULL, &format);
> +	if (ret)
> +		return ret;
> +
> +	v4l2_fill_pix_format(pixfmt, &format.format);
> +
> +	pixfmt->bytesperline = (pixfmt->width * csi_fmt->bpp) >> 3;
> +	pixfmt->sizeimage = (pixfmt->width * csi_fmt->bpp * pixfmt->height) / 8;
> +
> +	if (current_fmt)
> +		*current_fmt = csi_fmt;
> +
> +	return 0;
> +}
> +
> +static int sun6i_video_set_fmt(struct sun6i_video *video, struct v4l2_format *f)
> +{
> +	struct v4l2_subdev_format format;
> +	struct sun6i_csi_format *current_fmt;
> +	struct v4l2_subdev *subdev;
> +	u32 pad;
> +	int ret;
> +
> +	subdev = sun6i_video_remote_subdev(video, &pad);
> +	if (subdev == NULL)
> +		return -ENXIO;
> +
> +	ret = sun6i_video_try_fmt(video, f, &current_fmt);
> +	if (ret)
> +		return ret;
> +
> +	format.which = V4L2_SUBDEV_FORMAT_ACTIVE;
> +	v4l2_fill_mbus_format(&format.format, &f->fmt.pix,
> +			      current_fmt->mbus_code);
> +	ret = v4l2_subdev_call(subdev, pad, set_fmt, NULL, &format);
> +	if (ret < 0)
> +		return ret;
> +
> +	video->fmt = *f;
> +	video->current_fmt = current_fmt;
> +
> +	return 0;
> +}
> +
> +static int vidioc_s_fmt_vid_cap(struct file *file, void *priv,
> +				struct v4l2_format *f)
> +{
> +	struct sun6i_video *video = video_drvdata(file);
> +
> +	if (vb2_is_streaming(&video->vb2_vidq))

This should be vb2_is_busy(). Once buffers are allocated you are no longer allowed
to change the format, regardless of whether you are streaming or not.

> +		return -EBUSY;
> +
> +	return sun6i_video_set_fmt(video, f);
> +}
> +
> +static int vidioc_try_fmt_vid_cap(struct file *file, void *priv,
> +				  struct v4l2_format *f)
> +{
> +	struct sun6i_video *video = video_drvdata(file);
> +
> +	return sun6i_video_try_fmt(video, f, NULL);
> +}
> +
> +static const struct v4l2_ioctl_ops sun6i_video_ioctl_ops = {
> +	.vidioc_querycap		= vidioc_querycap,
> +	.vidioc_enum_fmt_vid_cap	= vidioc_enum_fmt_vid_cap,
> +	.vidioc_g_fmt_vid_cap		= vidioc_g_fmt_vid_cap,
> +	.vidioc_s_fmt_vid_cap		= vidioc_s_fmt_vid_cap,
> +	.vidioc_try_fmt_vid_cap		= vidioc_try_fmt_vid_cap,
> +
> +	.vidioc_reqbufs			= vb2_ioctl_reqbufs,
> +	.vidioc_querybuf		= vb2_ioctl_querybuf,
> +	.vidioc_qbuf			= vb2_ioctl_qbuf,
> +	.vidioc_expbuf			= vb2_ioctl_expbuf,
> +	.vidioc_dqbuf			= vb2_ioctl_dqbuf,
> +	.vidioc_create_bufs		= vb2_ioctl_create_bufs,
> +	.vidioc_prepare_buf		= vb2_ioctl_prepare_buf,
> +	.vidioc_streamon		= vb2_ioctl_streamon,
> +	.vidioc_streamoff		= vb2_ioctl_streamoff,
> +};
> +
> +/* -----------------------------------------------------------------------------
> + * V4L2 file operations
> + */
> +static int sun6i_video_open(struct file *file)
> +{
> +	struct sun6i_video *video = video_drvdata(file);
> +	struct v4l2_format format;
> +	int ret;
> +
> +	if (mutex_lock_interruptible(&video->lock))
> +		return -ERESTARTSYS;
> +
> +	ret = v4l2_fh_open(file);
> +	if (ret < 0)
> +		goto unlock;
> +
> +	ret = v4l2_pipeline_pm_use(&video->vdev.entity, 1);
> +	if (ret < 0)
> +		goto fh_release;
> +
> +	if (!v4l2_fh_is_singular_file(file))
> +		goto unlock;
> +
> +	ret = sun6i_csi_set_power(video->csi, true);
> +	if (ret < 0)
> +		goto fh_release;
> +
> +	/* setup default format */
> +	if (video->num_formats > 0) {
> +		format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> +		format.fmt.pix.width = 1280;
> +		format.fmt.pix.height = 720;
> +		format.fmt.pix.pixelformat = video->formats[0].fourcc;
> +		sun6i_video_set_fmt(video, &format);
> +	}

No, this should happen when the driver is initialized. The format is
persistent over open()/close() calls so should not be re-initialized
here.

> +
> +	mutex_unlock(&video->lock);
> +	return 0;
> +
> +fh_release:
> +	v4l2_fh_release(file);
> +unlock:
> +	mutex_unlock(&video->lock);
> +	return ret;
> +}
> +
> +static int sun6i_video_close(struct file *file)
> +{
> +	struct sun6i_video *video = video_drvdata(file);
> +	bool last_fh;
> +
> +	mutex_lock(&video->lock);
> +
> +	last_fh = v4l2_fh_is_singular_file(file);
> +
> +	_vb2_fop_release(file, NULL);
> +
> +	v4l2_pipeline_pm_use(&video->vdev.entity, 0);
> +
> +	if (last_fh)
> +		sun6i_csi_set_power(video->csi, false);
> +
> +	mutex_unlock(&video->lock);
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_file_operations sun6i_video_fops = {
> +	.owner		= THIS_MODULE,
> +	.open		= sun6i_video_open,
> +	.release	= sun6i_video_close,
> +	.unlocked_ioctl	= video_ioctl2,
> +	.mmap		= vb2_fop_mmap,
> +	.poll		= vb2_fop_poll
> +};
> +
> +/* -----------------------------------------------------------------------------
> + * Media Operations
> + */
> +static int sun6i_video_formats_init(struct sun6i_video *video)
> +{
> +	struct v4l2_subdev_mbus_code_enum mbus_code = { 0 };
> +	struct sun6i_csi *csi = video->csi;
> +	struct v4l2_subdev *subdev;
> +	u32 pad;
> +	const u32 *pixformats;
> +	int pixformat_count = 0;
> +	u32 subdev_codes[32]; /* subdev format codes, 32 should be enough */
> +	int codes_count = 0;
> +	int num_fmts = 0;
> +	int i, j;
> +
> +	subdev = sun6i_video_remote_subdev(video, &pad);
> +	if (subdev == NULL)
> +		return -ENXIO;
> +
> +	/* Get supported pixformats of CSI */
> +	pixformat_count = sun6i_csi_get_supported_pixformats(csi, &pixformats);
> +	if (pixformat_count <= 0)
> +		return -ENXIO;
> +
> +	/* Get subdev formats codes */
> +	mbus_code.pad = pad;
> +	mbus_code.which = V4L2_SUBDEV_FORMAT_ACTIVE;
> +	while (!v4l2_subdev_call(subdev, pad, enum_mbus_code, NULL,
> +			&mbus_code)) {
> +		subdev_codes[codes_count] = mbus_code.code;

This definitely needs a check when codes_count >= ARRAY_SIZE(subdev_codes).

> +		codes_count++;
> +		mbus_code.index++;
> +	}
> +
> +	if (!codes_count)
> +		return -ENXIO;
> +
> +	/* Get supported formats count */
> +	for (i = 0; i < codes_count; i++) {
> +		for (j = 0; j < pixformat_count; j++) {
> +			if (!sun6i_csi_is_format_support(csi, pixformats[j],
> +					mbus_code.code)) {
> +				continue;
> +			}
> +			num_fmts++;
> +		}
> +	}
> +
> +	if (!num_fmts)
> +		return -ENXIO;
> +
> +	video->num_formats = num_fmts;
> +	video->formats = devm_kcalloc(video->csi->dev, num_fmts,
> +			sizeof(struct sun6i_csi_format), GFP_KERNEL);
> +	if (!video->formats) {
> +		dev_err(video->csi->dev, "could not allocate memory\n");
> +		return -ENOMEM;
> +	}
> +
> +	/* Get supported formats */
> +	num_fmts = 0;
> +	for (i = 0; i < codes_count; i++) {
> +		for (j = 0; j < pixformat_count; j++) {
> +			if (!sun6i_csi_is_format_support(csi, pixformats[j],
> +					mbus_code.code)) {
> +				continue;
> +			}
> +
> +			video->formats[num_fmts].fourcc = pixformats[j];
> +			video->formats[num_fmts].mbus_code =
> +					mbus_code.code;
> +			video->formats[num_fmts].bpp =
> +					v4l2_pixformat_get_bpp(pixformats[j]);
> +			num_fmts++;
> +		}
> +	}

As mentioned above, the initial format should probably be configure here.

> +
> +	return 0;
> +}
> +
> +static int sun6i_video_link_setup(struct media_entity *entity,
> +				  const struct media_pad *local,
> +				  const struct media_pad *remote, u32 flags)
> +{
> +	struct video_device *vdev = media_entity_to_video_device(entity);
> +	struct sun6i_video *video = video_get_drvdata(vdev);
> +
> +	if (WARN_ON(video == NULL))
> +		return 0;
> +
> +	return sun6i_video_formats_init(video);

Why is this called here? Why not in video_init()?

> +}
> +
> +static const struct media_entity_operations sun6i_video_media_ops = {
> +	.link_setup = sun6i_video_link_setup,
> +};
> +
> +int sun6i_video_init(struct sun6i_video *video, struct sun6i_csi *csi,
> +		     const char *name)
> +{
> +	struct video_device *vdev = &video->vdev;
> +	struct vb2_queue *vidq = &video->vb2_vidq;
> +	int ret;
> +
> +	video->csi = csi;
> +
> +	/* Initialize the media entity... */
> +	video->pad.flags = MEDIA_PAD_FL_SINK | MEDIA_PAD_FL_MUST_CONNECT;
> +	vdev->entity.ops = &sun6i_video_media_ops;
> +	ret = media_entity_pads_init(&vdev->entity, 1, &video->pad);
> +	if (ret < 0)
> +		return ret;
> +
> +	mutex_init(&video->lock);
> +
> +	INIT_LIST_HEAD(&video->dma_queue);
> +	spin_lock_init(&video->dma_queue_lock);
> +
> +	video->cur_frm = NULL;
> +	video->sequence = 0;
> +	video->num_formats = 0;
> +
> +	/* Initialize videobuf2 queue */
> +	vidq->type			= V4L2_BUF_TYPE_VIDEO_CAPTURE;
> +	vidq->io_modes			= VB2_MMAP | VB2_DMABUF;
> +	vidq->drv_priv			= video;
> +	vidq->buf_struct_size		= sizeof(struct sun6i_csi_buffer);
> +	vidq->ops			= &sun6i_csi_vb2_ops;
> +	vidq->mem_ops			= &vb2_dma_contig_memops;
> +	vidq->timestamp_flags		= V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
> +	vidq->lock			= &video->lock;
> +	vidq->min_buffers_needed	= 1;
> +	vidq->dev			= csi->dev;
> +
> +	ret = vb2_queue_init(vidq);
> +	if (ret) {
> +		v4l2_err(&csi->v4l2_dev, "vb2_queue_init failed: %d\n", ret);
> +		goto error;
> +	}
> +
> +	/* Register video device */
> +	strlcpy(vdev->name, name, sizeof(vdev->name));
> +	vdev->release		= video_device_release_empty;
> +	vdev->fops		= &sun6i_video_fops;
> +	vdev->ioctl_ops		= &sun6i_video_ioctl_ops;
> +	vdev->vfl_type		= VFL_TYPE_GRABBER;
> +	vdev->vfl_dir		= VFL_DIR_RX;
> +	vdev->v4l2_dev		= &csi->v4l2_dev;
> +	vdev->queue		= vidq;
> +	vdev->lock		= &video->lock;
> +	vdev->device_caps	= V4L2_CAP_STREAMING | V4L2_CAP_VIDEO_CAPTURE;
> +	video_set_drvdata(vdev, video);
> +
> +	ret = video_register_device(vdev, VFL_TYPE_GRABBER, -1);
> +	if (ret < 0) {
> +		v4l2_err(&csi->v4l2_dev,
> +			 "video_register_device failed: %d\n", ret);
> +		goto error;
> +	}
> +
> +	return 0;
> +
> +error:
> +	sun6i_video_cleanup(video);
> +	return ret;
> +}
> +
> +void sun6i_video_cleanup(struct sun6i_video *video)
> +{
> +	if (video_is_registered(&video->vdev))
> +		video_unregister_device(&video->vdev);
> +
> +	media_entity_cleanup(&video->vdev.entity);
> +}
> diff --git a/drivers/media/platform/sun6i-csi/sun6i_video.h b/drivers/media/platform/sun6i-csi/sun6i_video.h
> new file mode 100644
> index 0000000..14eac6e
> --- /dev/null
> +++ b/drivers/media/platform/sun6i-csi/sun6i_video.h
> @@ -0,0 +1,61 @@
> +/*
> + * Copyright (c) 2017 Yong Deng <yong.deng@magewell.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.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#ifndef __SUN6I_VIDEO_H__
> +#define __SUN6I_VIDEO_H__
> +
> +#include <media/v4l2-dev.h>
> +#include <media/videobuf2-core.h>
> +
> +/*
> + * struct sun6i_csi_format - CSI media bus format information
> + * @fourcc: Fourcc code for this format
> + * @mbus_code: V4L2 media bus format code.
> + * @bpp: Bytes per pixel (when stored in memory)
> + */
> +struct sun6i_csi_format {
> +	u32				fourcc;
> +	u32				mbus_code;
> +	u8				bpp;
> +};
> +
> +struct sun6i_csi;
> +
> +struct sun6i_video {
> +	struct video_device		vdev;
> +	struct media_pad		pad;
> +	struct sun6i_csi		*csi;
> +
> +	struct mutex			lock;
> +
> +	struct vb2_queue		vb2_vidq;
> +	spinlock_t			dma_queue_lock;
> +	struct list_head		dma_queue;
> +
> +	struct sun6i_csi_buffer		*cur_frm;
> +	unsigned int			sequence;
> +
> +	struct sun6i_csi_format		*formats;
> +	unsigned int			num_formats;
> +	struct sun6i_csi_format		*current_fmt;
> +	struct v4l2_format		fmt;
> +};
> +
> +int sun6i_video_init(struct sun6i_video *video, struct sun6i_csi *csi,
> +		     const char *name);
> +void sun6i_video_cleanup(struct sun6i_video *video);
> +
> +void sun6i_video_frame_done(struct sun6i_video *video);
> +
> +#endif /* __SUN6I_VIDEO_H__ */
> 

Regards,

	Hans