Re: [RFC PATCH v2 12/18] media: tegra-video: Add support for selection ioctl ops

[Sowjanya Komatineni <skomatineni@nvidia.com>]

On 7/2/20 6:54 AM, Hans Verkuil wrote:
> On 17/06/2020 03:41, Sowjanya Komatineni wrote:
>> This patch adds selection v4l2 ioctl operations to allow configuring
>> a selection rectangle in the sensor through the Tegra video device
>> node.
>>
>> Some sensor drivers supporting crop uses try_crop rectangle from
>> v4l2_subdev_pad_config during try format for computing binning.
>>
>> So with selection ops support, this patch also updates try format
>> to use try crop rectangle either from subdev frame size enumeration
>> or from subdev crop boundary.
>>
>> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
>> ---
>>   drivers/staging/media/tegra-video/vi.c | 106 +++++++++++++++++++++++++++++++++
>>   1 file changed, 106 insertions(+)
>>
>> diff --git a/drivers/staging/media/tegra-video/vi.c b/drivers/staging/media/tegra-video/vi.c
>> index 506c263..f9eb96b 100644
>> --- a/drivers/staging/media/tegra-video/vi.c
>> +++ b/drivers/staging/media/tegra-video/vi.c
>> @@ -427,6 +427,13 @@ static int __tegra_channel_try_format(struct tegra_vi_channel *chan,
>>   	struct v4l2_subdev *subdev;
>>   	struct v4l2_subdev_format fmt;
>>   	struct v4l2_subdev_pad_config *pad_cfg;
>> +	struct v4l2_subdev_frame_size_enum fse = {
>> +		.which = V4L2_SUBDEV_FORMAT_TRY,
>> +	};
>> +	struct v4l2_subdev_selection sdsel = {
>> +		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
>> +		.target = V4L2_SEL_TGT_CROP_BOUNDS,
>> +	};
>>   	int ret;
>>   
>>   	subdev = tegra_channel_get_remote_subdev(chan, true);
>> @@ -449,6 +456,24 @@ static int __tegra_channel_try_format(struct tegra_vi_channel *chan,
>>   	fmt.which = V4L2_SUBDEV_FORMAT_TRY;
>>   	fmt.pad = 0;
>>   	v4l2_fill_mbus_format(&fmt.format, pix, fmtinfo->code);
>> +
>> +	/*
>> +	 * Attempt to obtain the format size from subdev.
>> +	 * If not available, try to get crop boundary from subdev.
>> +	 */
>> +	fse.code = fmtinfo->code;
>> +	ret = v4l2_subdev_call(subdev, pad, enum_frame_size, pad_cfg, &fse);
>> +	if (ret) {
>> +		ret = v4l2_subdev_call(subdev, pad, get_selection, NULL, &sdsel);
>> +		if (ret)
>> +			return -EINVAL;
>> +		pad_cfg->try_crop.width = sdsel.r.width;
>> +		pad_cfg->try_crop.height = sdsel.r.height;
>> +	} else {
>> +		pad_cfg->try_crop.width = fse.max_width;
>> +		pad_cfg->try_crop.height = fse.max_height;
>> +	}
>> +
>>   	ret = v4l2_subdev_call(subdev, pad, set_fmt, pad_cfg, &fmt);
>>   	if (ret < 0)
>>   		return ret;
>> @@ -540,6 +565,85 @@ static int tegra_channel_set_subdev_active_fmt(struct tegra_vi_channel *chan)
>>   	return 0;
>>   }
>>   
>> +static int tegra_channel_g_selection(struct file *file, void *priv,
>> +				     struct v4l2_selection *sel)
>> +{
>> +	struct tegra_vi_channel *chan = video_drvdata(file);
>> +	struct v4l2_subdev *subdev;
>> +	struct v4l2_subdev_format fmt = {
>> +		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
>> +	};
>> +	struct v4l2_subdev_selection sdsel = {
>> +		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
>> +		.target = sel->target,
>> +	};
>> +	int ret;
>> +
>> +	if (IS_ENABLED(CONFIG_VIDEO_TEGRA_TPG))
>> +		return -ENOTTY;
>> +
>> +	if (sel->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
>> +		return -EINVAL;
>> +	/*
>> +	 * Try the get selection operation and fallback to get format if not
>> +	 * implemented.
>> +	 */
>> +	subdev = tegra_channel_get_remote_subdev(chan, true);
>> +	ret = v4l2_subdev_call(subdev, pad, get_selection, NULL, &sdsel);
>> +	if (!ret)
>> +		sel->r = sdsel.r;
>> +	if (ret != -ENOIOCTLCMD)
>> +		return ret;
>> +
>> +	ret = v4l2_subdev_call(subdev, pad, get_fmt, NULL, &fmt);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	sel->r.left = 0;
>> +	sel->r.top = 0;
>> +	sel->r.width = fmt.format.width;
>> +	sel->r.height = fmt.format.height;
>> +
>> +	return 0;
>> +}
>> +
>> +static int tegra_channel_s_selection(struct file *file, void *fh,
>> +				     struct v4l2_selection *sel)
>> +{
>> +	struct tegra_vi_channel *chan = video_drvdata(file);
>> +	struct v4l2_subdev *subdev;
>> +	int ret;
>> +	struct v4l2_subdev_selection sdsel = {
>> +		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
>> +		.target = sel->target,
>> +		.flags = sel->flags,
>> +		.r = sel->r,
>> +	};
>> +
> This function doesn't check if the subdev actually supports set_selection.
> The imx219 is one such driver: it supports get_selection, but not set_selection.
>
> So this code should add these lines to fix the v4l2-compliance fail:
>
>         subdev = tegra_channel_get_remote_subdev(chan, true);
>
>         if (!v4l2_subdev_has_op(subdev, pad, set_selection))
>                 return -ENOTTY;
>
v4l2_subdev_call() does that check and returns -ENOIOCTLCMD when 
specified subdev ops does not exist.
>> +	if (IS_ENABLED(CONFIG_VIDEO_TEGRA_TPG))
>> +		return -ENOTTY;
>> +
>> +	if (sel->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
>> +		return -EINVAL;
>> +
>> +	if (vb2_is_busy(&chan->queue))
>> +		return -EBUSY;
>> +
>> +	subdev = tegra_channel_get_remote_subdev(chan, true);
> And this line can be dropped.
>
> Regards,
>
> 	Hans
>
>> +	ret = v4l2_subdev_call(subdev, pad, set_selection, NULL, &sdsel);
>> +	if (!ret) {
>> +		sel->r = sdsel.r;
>> +		/*
>> +		 * Subdev active format resolution may have changed during
>> +		 * set selection operation. So, update channel format to
>> +		 * the sub-device active format.
>> +		 */
>> +		return tegra_channel_set_subdev_active_fmt(chan);
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>>   static int tegra_channel_enum_input(struct file *file, void *fh,
>>   				    struct v4l2_input *inp)
>>   {
>> @@ -597,6 +701,8 @@ static const struct v4l2_ioctl_ops tegra_channel_ioctl_ops = {
>>   	.vidioc_streamoff		= vb2_ioctl_streamoff,
>>   	.vidioc_subscribe_event		= v4l2_ctrl_subscribe_event,
>>   	.vidioc_unsubscribe_event	= v4l2_event_unsubscribe,
>> +	.vidioc_g_selection		= tegra_channel_g_selection,
>> +	.vidioc_s_selection		= tegra_channel_s_selection,
>>   };
>>   
>>   /*
>>