Re: [PATCH v11 21/32] rcar-vin: use different v4l2 operations in media controller mode

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Niklas,

Thank you for the patch.

On Friday, 2 March 2018 03:57:40 EET Niklas Söderlund wrote:
> When the driver runs in media controller mode it should not directly
> control the subdevice instead userspace will be responsible for
> configuring the pipeline. To be able to run in this mode a different set
> of v4l2 operations needs to be used.
> 
> Add a new set of v4l2 operations to support operation without directly
> interacting with the source subdevice.
> 
> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com>
> ---
>  drivers/media/platform/rcar-vin/rcar-dma.c  |   3 +-
>  drivers/media/platform/rcar-vin/rcar-v4l2.c | 161 ++++++++++++++++++++++++-
>  2 files changed, 160 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/platform/rcar-vin/rcar-dma.c
> b/drivers/media/platform/rcar-vin/rcar-dma.c index
> 3fb9c325285c5a5a..27d0c098f1da40f9 100644
> --- a/drivers/media/platform/rcar-vin/rcar-dma.c
> +++ b/drivers/media/platform/rcar-vin/rcar-dma.c
> @@ -628,7 +628,8 @@ static int rvin_setup(struct rvin_dev *vin)
>  		/* Default to TB */
>  		vnmc = VNMC_IM_FULL;
>  		/* Use BT if video standard can be read and is 60 Hz format */
> -		if (!v4l2_subdev_call(vin_to_source(vin), video, g_std, &std)) {
> +		if (!vin->info->use_mc &&
> +		    !v4l2_subdev_call(vin_to_source(vin), video, g_std, &std)) {

To avoid spreading the discussion across several mail threads, I'll repeat my 
comment made today on v9:

> > I think the subdev should be queried in rcar-v4l2.c and the information
> > cached in the rvin_dev structure instead of queried here. Interactions
> > with the subdev should be minimized in rvin-dma.c. You can fix this in a
> > separate patch if you prefer.
>
> This can't be a cached value it needs to be read at stream on time. The
> input source could have changed format, e.g. the user may have
> disconnected a NTSC source and plugged in a PAL.

Please note that in that case the source subdev will not have changed its 
format yet, it only does so when the s_std operation is called.

> This is a shame as I otherwise agree with you that interactions with the
> subdevice should be kept at a minimum.

>  			if (std & V4L2_STD_525_60)
>  				vnmc = VNMC_IM_FULL | VNMC_FOC;
>  		}
> diff --git a/drivers/media/platform/rcar-vin/rcar-v4l2.c
> b/drivers/media/platform/rcar-vin/rcar-v4l2.c index
> 20be21cb1cf521e5..8d92710efffa7276 100644
> --- a/drivers/media/platform/rcar-vin/rcar-v4l2.c
> +++ b/drivers/media/platform/rcar-vin/rcar-v4l2.c
> @@ -18,12 +18,16 @@
> 
>  #include <media/v4l2-event.h>
>  #include <media/v4l2-ioctl.h>
> +#include <media/v4l2-mc.h>
>  #include <media/v4l2-rect.h>
> 
>  #include "rcar-vin.h"
> 
>  #define RVIN_DEFAULT_FORMAT	V4L2_PIX_FMT_YUYV
> +#define RVIN_DEFAULT_WIDTH	800
> +#define RVIN_DEFAULT_HEIGHT	600
>  #define RVIN_DEFAULT_FIELD	V4L2_FIELD_NONE
> +#define RVIN_DEFAULT_COLORSPACE	V4L2_COLORSPACE_SRGB
> 
>  /* ------------------------------------------------------------------------
>   * Format Conversions
> @@ -667,6 +671,74 @@ static const struct v4l2_ioctl_ops rvin_ioctl_ops = {
>  	.vidioc_unsubscribe_event	= v4l2_event_unsubscribe,
>  };
> 
> +/* ------------------------------------------------------------------------
> + * V4L2 Media Controller
> + */
> +
> +static int rvin_mc_try_fmt_vid_cap(struct file *file, void *priv,
> +				   struct v4l2_format *f)
> +{
> +	struct rvin_dev *vin = video_drvdata(file);
> +
> +	return rvin_format_align(vin, &f->fmt.pix);
> +}
> +
> +static int rvin_mc_s_fmt_vid_cap(struct file *file, void *priv,
> +				 struct v4l2_format *f)
> +{
> +	struct rvin_dev *vin = video_drvdata(file);
> +	int ret;
> +
> +	if (vb2_is_busy(&vin->queue))
> +		return -EBUSY;
> +
> +	ret = rvin_format_align(vin, &f->fmt.pix);
> +	if (ret)
> +		return ret;
> +
> +	vin->format = f->fmt.pix;
> +
> +	return 0;
> +}
> +
> +static int rvin_mc_enum_input(struct file *file, void *priv,
> +			      struct v4l2_input *i)
> +{
> +	if (i->index != 0)
> +		return -EINVAL;
> +
> +	i->type = V4L2_INPUT_TYPE_CAMERA;
> +	strlcpy(i->name, "Camera", sizeof(i->name));
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_ioctl_ops rvin_mc_ioctl_ops = {
> +	.vidioc_querycap		= rvin_querycap,
> +	.vidioc_try_fmt_vid_cap		= rvin_mc_try_fmt_vid_cap,
> +	.vidioc_g_fmt_vid_cap		= rvin_g_fmt_vid_cap,
> +	.vidioc_s_fmt_vid_cap		= rvin_mc_s_fmt_vid_cap,
> +	.vidioc_enum_fmt_vid_cap	= rvin_enum_fmt_vid_cap,
> +
> +	.vidioc_enum_input		= rvin_mc_enum_input,
> +	.vidioc_g_input			= rvin_g_input,
> +	.vidioc_s_input			= rvin_s_input,
> +
> +	.vidioc_reqbufs			= vb2_ioctl_reqbufs,
> +	.vidioc_create_bufs		= vb2_ioctl_create_bufs,
> +	.vidioc_querybuf		= vb2_ioctl_querybuf,
> +	.vidioc_qbuf			= vb2_ioctl_qbuf,
> +	.vidioc_dqbuf			= vb2_ioctl_dqbuf,
> +	.vidioc_expbuf			= vb2_ioctl_expbuf,
> +	.vidioc_prepare_buf		= vb2_ioctl_prepare_buf,
> +	.vidioc_streamon		= vb2_ioctl_streamon,
> +	.vidioc_streamoff		= vb2_ioctl_streamoff,
> +
> +	.vidioc_log_status		= v4l2_ctrl_log_status,
> +	.vidioc_subscribe_event		= rvin_subscribe_event,
> +	.vidioc_unsubscribe_event	= v4l2_event_unsubscribe,
> +};
> +
>  /* ------------------------------------------------------------------------
>   * File Operations
>   */
> @@ -810,6 +882,74 @@ static const struct v4l2_file_operations rvin_fops = {
>  	.read		= vb2_fop_read,
>  };
> 
> +/* ------------------------------------------------------------------------
> + * Media controller file operations
> + */
> +
> +static int rvin_mc_open(struct file *file)
> +{
> +	struct rvin_dev *vin = video_drvdata(file);
> +	int ret;
> +
> +	ret = mutex_lock_interruptible(&vin->lock);
> +	if (ret)
> +		return ret;
> +
> +	ret = pm_runtime_get_sync(vin->dev);
> +	if (ret < 0)
> +		goto err_pm;
> +
> +	ret = v4l2_pipeline_pm_use(&vin->vdev.entity, 1);
> +	if (ret < 0)
> +		goto err_v4l2pm;
> +
> +	file->private_data = vin;
> +
> +	ret = v4l2_fh_open(file);
> +	if (ret)
> +		goto err_open;
> +
> +	mutex_unlock(&vin->lock);
> +
> +	return 0;
> +err_open:
> +	v4l2_pipeline_pm_use(&vin->vdev.entity, 0);
> +err_v4l2pm:
> +	pm_runtime_put(vin->dev);
> +err_pm:
> +	mutex_unlock(&vin->lock);

Error labels should be named according to the action performed in the cleanup 
path, not based on the error that causes to jump to them.

> +	return ret;
> +}
> +
> +static int rvin_mc_release(struct file *file)
> +{
> +	struct rvin_dev *vin = video_drvdata(file);
> +	int ret;
> +
> +	mutex_lock(&vin->lock);
> +
> +	/* the release helper will cleanup any on-going streaming. */
> +	ret = _vb2_fop_release(file, NULL);
> +
> +	v4l2_pipeline_pm_use(&vin->vdev.entity, 0);
> +	pm_runtime_put(vin->dev);
> +
> +	mutex_unlock(&vin->lock);
> +
> +	return ret;
> +}
> +
> +static const struct v4l2_file_operations rvin_mc_fops = {
> +	.owner		= THIS_MODULE,
> +	.unlocked_ioctl	= video_ioctl2,
> +	.open		= rvin_mc_open,
> +	.release	= rvin_mc_release,
> +	.poll		= vb2_fop_poll,
> +	.mmap		= vb2_fop_mmap,
> +	.read		= vb2_fop_read,
> +};
> +
>  void rvin_v4l2_unregister(struct rvin_dev *vin)
>  {
>  	if (!video_is_registered(&vin->vdev))
> @@ -845,18 +985,33 @@ int rvin_v4l2_register(struct rvin_dev *vin)
>  	vin->v4l2_dev.notify = rvin_notify;
> 
>  	/* video node */
> -	vdev->fops = &rvin_fops;
>  	vdev->v4l2_dev = &vin->v4l2_dev;
>  	vdev->queue = &vin->queue;
>  	strlcpy(vdev->name, KBUILD_MODNAME, sizeof(vdev->name));
>  	vdev->release = video_device_release_empty;
> -	vdev->ioctl_ops = &rvin_ioctl_ops;
>  	vdev->lock = &vin->lock;
>  	vdev->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING |
>  		V4L2_CAP_READWRITE;
> 
> +	/* Set a default format */
>  	vin->format.pixelformat	= RVIN_DEFAULT_FORMAT;
> -	rvin_reset_format(vin);
> +	vin->format.width = RVIN_DEFAULT_WIDTH;
> +	vin->format.height = RVIN_DEFAULT_HEIGHT;
> +	vin->format.field = RVIN_DEFAULT_FIELD;
> +	vin->format.colorspace = RVIN_DEFAULT_COLORSPACE;
> +
> +	if (vin->info->use_mc) {
> +		vdev->fops = &rvin_mc_fops;
> +		vdev->ioctl_ops = &rvin_mc_ioctl_ops;
> +	} else {
> +		vdev->fops = &rvin_fops;
> +		vdev->ioctl_ops = &rvin_ioctl_ops;
> +		rvin_reset_format(vin);
> +	}
> +
> +	ret = rvin_format_align(vin, &vin->format);
> +	if (ret)
> +		return ret;
> 
>  	ret = video_register_device(&vin->vdev, VFL_TYPE_GRABBER, -1);
>  	if (ret) {

-- 
Regards,

Laurent Pinchart