Re: [PATCH v3 1/5] v4l2-dev/ioctl: Add V4L2_CAP_IO_MC

[Helen Koike <helen.koike@collabora.com>]

On 2/14/20 11:25 AM, Hans Verkuil wrote:
> On 1/22/20 10:50 PM, Helen Koike wrote:
>> Hi Niklas,
>>
>> On 1/12/20 9:24 PM, Niklas Söderlund wrote:
>>> Add a video device capability flag to indicate that its inputs and/or
>>> outputs are controlled by the Media Controller instead of the V4L2 API.
>>> When this flag is set, ioctl for enum inputs and outputs are
>>> automatically enabled and programmed to call a helper function.
>>>
>>> As a bonus fallback default handlers for VIDIOC_{G,S}_{INPUT,OUTPUT} are
>>> provided which can be used by drivers who only provide one input/output.
>>> Such drivers need just not declare vidioc_{g,s}_{input,output} in its
>>> struct v4l2_ioctl_ops and v4l2 will fallback to the single input/output
>>> defaults.
>>>
>>> Suggested-by: Hans Verkuil <hverkuil@xs4all.nl>
>>> Signed-off-by: Helen Koike <helen.koike@collabora.com>
>>> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
>>> ---
>>> * Changes since v2
>>> - Merged the two patches touching V4L2 core stuff to a single patch.
>>> - Updated documentation for V4L2_CAP_IO_MC
>>> - Added is_io_mc bool in determine_valid_ioctls()
>>> - Folded or moved code closer to where it's used
>>> - Remove unneeded memset()
>>> - Use strscpy() instead of strlcpy()
>>> ---
>>>  .../media/uapi/v4l/vidioc-querycap.rst        |  5 ++
>>>  .../media/videodev2.h.rst.exceptions          |  1 +
>>>  drivers/media/v4l2-core/v4l2-dev.c            | 19 +++--
>>>  drivers/media/v4l2-core/v4l2-ioctl.c          | 69 +++++++++++++++++--
>>>  include/uapi/linux/videodev2.h                |  2 +
>>>  5 files changed, 86 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/Documentation/media/uapi/v4l/vidioc-querycap.rst b/Documentation/media/uapi/v4l/vidioc-querycap.rst
>>> index 5f9930195d624c73..da17e0e3c6f9a571 100644
>>> --- a/Documentation/media/uapi/v4l/vidioc-querycap.rst
>>> +++ b/Documentation/media/uapi/v4l/vidioc-querycap.rst
>>> @@ -264,6 +264,11 @@ specification the ioctl returns an ``EINVAL`` error code.
>>>      * - ``V4L2_CAP_TOUCH``
>>>        - 0x10000000
>>>        - This is a touch device.
>>> +    * - ``V4L2_CAP_IO_MC``
>>> +      - 0x20000000
>>> +      - There is only one input and/or output seen from userspace. Which I/O
>>> +        entity is routed to the input/output is controlled by the Media
>>> +        Controller. See :ref:`media_controller`.
>>>      * - ``V4L2_CAP_DEVICE_CAPS``
>>>        - 0x80000000
>>>        - The driver fills the ``device_caps`` field. This capability can
>>> diff --git a/Documentation/media/videodev2.h.rst.exceptions b/Documentation/media/videodev2.h.rst.exceptions
>>> index cb6ccf91776e6b56..a625fb90e3a989a7 100644
>>> --- a/Documentation/media/videodev2.h.rst.exceptions
>>> +++ b/Documentation/media/videodev2.h.rst.exceptions
>>> @@ -176,6 +176,7 @@ replace define V4L2_CAP_STREAMING device-capabilities
>>>  replace define V4L2_CAP_META_OUTPUT device-capabilities
>>>  replace define V4L2_CAP_DEVICE_CAPS device-capabilities
>>>  replace define V4L2_CAP_TOUCH device-capabilities
>>> +replace define V4L2_CAP_IO_MC device-capabilities
>>>  
>>>  # V4L2 pix flags
>>>  replace define V4L2_PIX_FMT_PRIV_MAGIC :c:type:`v4l2_pix_format`
>>> diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
>>> index da42d172714adcb5..3c1a1200aa1fa9f3 100644
>>> --- a/drivers/media/v4l2-core/v4l2-dev.c
>>> +++ b/drivers/media/v4l2-core/v4l2-dev.c
>>> @@ -552,6 +552,7 @@ static void determine_valid_ioctls(struct video_device *vdev)
>>>  		       (vdev->device_caps & meta_caps);
>>>  	bool is_rx = vdev->vfl_dir != VFL_DIR_TX;
>>>  	bool is_tx = vdev->vfl_dir != VFL_DIR_RX;
>>> +	bool is_io_mc = vdev->device_caps & V4L2_CAP_IO_MC;
>>>  
>>>  	bitmap_zero(valid_ioctls, BASE_VIDIOC_PRIVATE);
>>>  
>>> @@ -725,22 +726,28 @@ static void determine_valid_ioctls(struct video_device *vdev)
>>>  		SET_VALID_IOCTL(ops, VIDIOC_G_STD, vidioc_g_std);
>>>  		if (is_rx) {
>>>  			SET_VALID_IOCTL(ops, VIDIOC_QUERYSTD, vidioc_querystd);
>>> -			SET_VALID_IOCTL(ops, VIDIOC_ENUMINPUT, vidioc_enum_input);
>>> -			SET_VALID_IOCTL(ops, VIDIOC_G_INPUT, vidioc_g_input);
>>> -			SET_VALID_IOCTL(ops, VIDIOC_S_INPUT, vidioc_s_input);
>>> +			set_bit(_IOC_NR(VIDIOC_G_INPUT), valid_ioctls);
>>> +			set_bit(_IOC_NR(VIDIOC_S_INPUT), valid_ioctls);
>>
>> Maybe I'm reading this wrong, but from what I understand, in case where
>> (!is_io_mc && !ops->vidioc_enum_input) is true, shouldn't {G,S}_INPUT be invalid?
>> Same for output.
> 
> Yup, that's right.
> 
> Niklas, why not just do:
> 
> 			if (is_io_mc) {
> 				set_bit(_IOC_NR(VIDIOC_ENUMINPUT), valid_ioctls);
> 				set_bit(_IOC_NR(VIDIOC_G_INPUT), valid_ioctls);
> 				set_bit(_IOC_NR(VIDIOC_S_INPUT), valid_ioctls);
> 			} else {
> 				SET_VALID_IOCTL(ops, VIDIOC_ENUMINPUT, vidioc_enum_input);
> 				SET_VALID_IOCTL(ops, VIDIOC_G_INPUT, vidioc_g_input);
> 				SET_VALID_IOCTL(ops, VIDIOC_S_INPUT, vidioc_s_input);
> 			}
> 
> and ditto for output.
> 
>>
>> Also, if this is a MC device, the default with your patch is to enumerate one input and one output right?
>> I'm just wondering if vimc should be updated too, as it doesn't implement these ioctls.
>> (or other drivers who doesn't implement them).
> 
> Yes, vimc should certainly be updated.
> 
>>
>> Maybe I understood this wrong (very likely), but does it make sense to enumerate
>> output in a Capture node? Or to enumerate input in an Output node?
> 
> No, that doesn't make sense. But why do you ask? That doesn't happen here, or am I
> missing something?

Please ignore, I misread something.

Regards,
Helen

> 
> Regards,
> 
> 	Hans
> 
>>
>> Regards,
>> Helen
>>
>>>  			SET_VALID_IOCTL(ops, VIDIOC_ENUMAUDIO, vidioc_enumaudio);
>>>  			SET_VALID_IOCTL(ops, VIDIOC_G_AUDIO, vidioc_g_audio);
>>>  			SET_VALID_IOCTL(ops, VIDIOC_S_AUDIO, vidioc_s_audio);
>>>  			SET_VALID_IOCTL(ops, VIDIOC_QUERY_DV_TIMINGS, vidioc_query_dv_timings);
>>>  			SET_VALID_IOCTL(ops, VIDIOC_S_EDID, vidioc_s_edid);
>>> +			if (is_io_mc)
>>> +				set_bit(_IOC_NR(VIDIOC_ENUMINPUT), valid_ioctls);
>>> +			else
>>> +				SET_VALID_IOCTL(ops, VIDIOC_ENUMINPUT, vidioc_enum_input);
>>>  		}
>>>  		if (is_tx) {
>>> -			SET_VALID_IOCTL(ops, VIDIOC_ENUMOUTPUT, vidioc_enum_output);
>>> -			SET_VALID_IOCTL(ops, VIDIOC_G_OUTPUT, vidioc_g_output);
>>> -			SET_VALID_IOCTL(ops, VIDIOC_S_OUTPUT, vidioc_s_output);
>>> +			set_bit(_IOC_NR(VIDIOC_G_OUTPUT), valid_ioctls);
>>> +			set_bit(_IOC_NR(VIDIOC_S_OUTPUT), valid_ioctls);
>>>  			SET_VALID_IOCTL(ops, VIDIOC_ENUMAUDOUT, vidioc_enumaudout);
>>>  			SET_VALID_IOCTL(ops, VIDIOC_G_AUDOUT, vidioc_g_audout);
>>>  			SET_VALID_IOCTL(ops, VIDIOC_S_AUDOUT, vidioc_s_audout);
>>> +			if (is_io_mc)
>>> +				set_bit(_IOC_NR(VIDIOC_ENUMOUTPUT), valid_ioctls);
>>> +			else
>>> +				SET_VALID_IOCTL(ops, VIDIOC_ENUMOUTPUT, vidioc_enum_output);
>>>  		}
>>>  		if (ops->vidioc_g_parm || ops->vidioc_g_std)
>>>  			set_bit(_IOC_NR(VIDIOC_G_PARM), valid_ioctls);
>>> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
>>> index aaf83e25427288fd..e8e15deeb8f36a9d 100644
>>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
>>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
>>> @@ -1085,6 +1085,28 @@ static int v4l_querycap(const struct v4l2_ioctl_ops *ops,
>>>  	return ret;
>>>  }
>>>  
>>> +static int v4l_g_input(const struct v4l2_ioctl_ops *ops,
>>> +		       struct file *file, void *fh, void *arg)
>>> +{
>>> +	if (!ops->vidioc_g_input) {
>>> +		*(unsigned int *)arg = 0;
>>> +		return 0;
>>> +	}
>>> +
>>> +	return ops->vidioc_g_input(file, fh, arg);
>>> +}
>>> +
>>> +static int v4l_g_output(const struct v4l2_ioctl_ops *ops,
>>> +		       struct file *file, void *fh, void *arg)
>>> +{
>>> +	if (!ops->vidioc_g_output) {
>>> +		*(unsigned int *)arg = 0;
>>> +		return 0;
>>> +	}
>>> +
>>> +	return ops->vidioc_g_output(file, fh, arg);
>>> +}
>>> +
>>>  static int v4l_s_input(const struct v4l2_ioctl_ops *ops,
>>>  				struct file *file, void *fh, void *arg)
>>>  {
>>> @@ -1094,12 +1116,19 @@ static int v4l_s_input(const struct v4l2_ioctl_ops *ops,
>>>  	ret = v4l_enable_media_source(vfd);
>>>  	if (ret)
>>>  		return ret;
>>> +
>>> +	if (!ops->vidioc_s_input)
>>> +		return  *(unsigned int *)arg ? -EINVAL : 0;
>>> +
>>>  	return ops->vidioc_s_input(file, fh, *(unsigned int *)arg);
>>>  }
>>>  
>>>  static int v4l_s_output(const struct v4l2_ioctl_ops *ops,
>>>  				struct file *file, void *fh, void *arg)
>>>  {
>>> +	if (!ops->vidioc_s_output)
>>> +		return  *(unsigned int *)arg ? -EINVAL : 0;
>>> +
>>>  	return ops->vidioc_s_output(file, fh, *(unsigned int *)arg);
>>>  }
>>>  
>>> @@ -1128,6 +1157,20 @@ static int v4l_s_priority(const struct v4l2_ioctl_ops *ops,
>>>  	return v4l2_prio_change(vfd->prio, &vfh->prio, *p);
>>>  }
>>>  
>>> +static int v4l2_ioctl_enum_input_mc(struct file *file, void *priv,
>>> +				    struct v4l2_input *i)
>>> +{
>>> +	struct video_device *vfd = video_devdata(file);
>>> +
>>> +	if (i->index)
>>> +		return -EINVAL;
>>> +
>>> +	strscpy(i->name, vfd->name, sizeof(i->name));
>>> +	i->type = V4L2_INPUT_TYPE_CAMERA;
>>> +
>>> +	return 0;
>>> +}
>>> +
>>>  static int v4l_enuminput(const struct v4l2_ioctl_ops *ops,
>>>  				struct file *file, void *fh, void *arg)
>>>  {
>>> @@ -1143,9 +1186,26 @@ static int v4l_enuminput(const struct v4l2_ioctl_ops *ops,
>>>  	if (is_valid_ioctl(vfd, VIDIOC_S_STD))
>>>  		p->capabilities |= V4L2_IN_CAP_STD;
>>>  
>>> +	if (vfd->device_caps & V4L2_CAP_IO_MC)
>>> +		return v4l2_ioctl_enum_input_mc(file, fh, p);
>>> +
>>>  	return ops->vidioc_enum_input(file, fh, p);
>>>  }
>>>  
>>> +static int v4l2_ioctl_enum_output_mc(struct file *file, void *priv,
>>> +				     struct v4l2_output *o)
>>> +{
>>> +	struct video_device *vfd = video_devdata(file);
>>> +
>>> +	if (o->index)
>>> +		return -EINVAL;
>>> +
>>> +	strscpy(o->name, vfd->name, sizeof(o->name));
>>> +	o->type = V4L2_OUTPUT_TYPE_ANALOG;
>>> +
>>> +	return 0;
>>> +}
>>> +
>>>  static int v4l_enumoutput(const struct v4l2_ioctl_ops *ops,
>>>  				struct file *file, void *fh, void *arg)
>>>  {
>>> @@ -1161,6 +1221,9 @@ static int v4l_enumoutput(const struct v4l2_ioctl_ops *ops,
>>>  	if (is_valid_ioctl(vfd, VIDIOC_S_STD))
>>>  		p->capabilities |= V4L2_OUT_CAP_STD;
>>>  
>>> +	if (vfd->device_caps & V4L2_CAP_IO_MC)
>>> +		return v4l2_ioctl_enum_output_mc(file, fh, p);
>>> +
>>>  	return ops->vidioc_enum_output(file, fh, p);
>>>  }
>>>  
>>> @@ -2678,10 +2741,8 @@ DEFINE_V4L_STUB_FUNC(expbuf)
>>>  DEFINE_V4L_STUB_FUNC(g_std)
>>>  DEFINE_V4L_STUB_FUNC(g_audio)
>>>  DEFINE_V4L_STUB_FUNC(s_audio)
>>> -DEFINE_V4L_STUB_FUNC(g_input)
>>>  DEFINE_V4L_STUB_FUNC(g_edid)
>>>  DEFINE_V4L_STUB_FUNC(s_edid)
>>> -DEFINE_V4L_STUB_FUNC(g_output)
>>>  DEFINE_V4L_STUB_FUNC(g_audout)
>>>  DEFINE_V4L_STUB_FUNC(s_audout)
>>>  DEFINE_V4L_STUB_FUNC(g_jpegcomp)
>>> @@ -2730,11 +2791,11 @@ static const struct v4l2_ioctl_info v4l2_ioctls[] = {
>>>  	IOCTL_INFO(VIDIOC_S_AUDIO, v4l_stub_s_audio, v4l_print_audio, INFO_FL_PRIO),
>>>  	IOCTL_INFO(VIDIOC_QUERYCTRL, v4l_queryctrl, v4l_print_queryctrl, INFO_FL_CTRL | INFO_FL_CLEAR(v4l2_queryctrl, id)),
>>>  	IOCTL_INFO(VIDIOC_QUERYMENU, v4l_querymenu, v4l_print_querymenu, INFO_FL_CTRL | INFO_FL_CLEAR(v4l2_querymenu, index)),
>>> -	IOCTL_INFO(VIDIOC_G_INPUT, v4l_stub_g_input, v4l_print_u32, 0),
>>> +	IOCTL_INFO(VIDIOC_G_INPUT, v4l_g_input, v4l_print_u32, 0),
>>>  	IOCTL_INFO(VIDIOC_S_INPUT, v4l_s_input, v4l_print_u32, INFO_FL_PRIO),
>>>  	IOCTL_INFO(VIDIOC_G_EDID, v4l_stub_g_edid, v4l_print_edid, INFO_FL_ALWAYS_COPY),
>>>  	IOCTL_INFO(VIDIOC_S_EDID, v4l_stub_s_edid, v4l_print_edid, INFO_FL_PRIO | INFO_FL_ALWAYS_COPY),
>>> -	IOCTL_INFO(VIDIOC_G_OUTPUT, v4l_stub_g_output, v4l_print_u32, 0),
>>> +	IOCTL_INFO(VIDIOC_G_OUTPUT, v4l_g_output, v4l_print_u32, 0),
>>>  	IOCTL_INFO(VIDIOC_S_OUTPUT, v4l_s_output, v4l_print_u32, INFO_FL_PRIO),
>>>  	IOCTL_INFO(VIDIOC_ENUMOUTPUT, v4l_enumoutput, v4l_print_enumoutput, INFO_FL_CLEAR(v4l2_output, index)),
>>>  	IOCTL_INFO(VIDIOC_G_AUDOUT, v4l_stub_g_audout, v4l_print_audioout, 0),
>>> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
>>> index 5f9357dcb0602126..c793263a37052856 100644
>>> --- a/include/uapi/linux/videodev2.h
>>> +++ b/include/uapi/linux/videodev2.h
>>> @@ -487,6 +487,8 @@ struct v4l2_capability {
>>>  
>>>  #define V4L2_CAP_TOUCH                  0x10000000  /* Is a touch device */
>>>  
>>> +#define V4L2_CAP_IO_MC			0x20000000  /* Is input/output controlled by the media controller */
>>> +
>>>  #define V4L2_CAP_DEVICE_CAPS            0x80000000  /* sets device capabilities field */
>>>  
>>>  /*
>>>
>