On 15/04/2020 01:36, Laurent Pinchart wrote:
> Hi Hans,
>
> On Tue, Apr 14, 2020 at 01:42:46PM +0200, Hans Verkuil wrote:
>> On 13/04/2020 22:23, 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.
>>>
>>> Suggested-by: Hans Verkuil <hverkuil@xxxxxxxxx>
>>> Signed-off-by: Helen Koike <helen.koike@xxxxxxxxxxxxx>
>>> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
>>> Acked-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
>>> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
>>> ---
>>> .../media/uapi/v4l/vidioc-querycap.rst | 6 ++
>>> .../media/videodev2.h.rst.exceptions | 1 +
>>> drivers/media/v4l2-core/v4l2-dev.c | 25 ++++++--
>>> drivers/media/v4l2-core/v4l2-ioctl.c | 57 +++++++++++++++++--
>>> include/uapi/linux/videodev2.h | 2 +
>>> 5 files changed, 81 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/Documentation/media/uapi/v4l/vidioc-querycap.rst b/Documentation/media/uapi/v4l/vidioc-querycap.rst
>>> index 5f9930195d624c73..497a6aa2cbebad71 100644
>>> --- a/Documentation/media/uapi/v4l/vidioc-querycap.rst
>>> +++ b/Documentation/media/uapi/v4l/vidioc-querycap.rst
>>> @@ -264,6 +264,12 @@ 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. The whole
>>> + video topology configuration, including which I/O entity is routed to
>>> + the input/output, is configured by userspace via 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 97b6a3af13614639..3048811450182185 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);
>>>
>>> @@ -725,9 +726,15 @@ 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);
>>> + if (is_io_mc && !is_meta) {
>>
>> I noticed the addition of !is_meta. Digging into the history I saw that it was
>> a request from Sakari in the v4 review. I must have missed that since I disagree
>> with that change.
>>
>> If IO_MC is set, then this applies to video/meta/vbi. After all, vbi is just a
>> special kind of metadata (and we'd use a metadata device node if we would design
>> that today), so it makes no sense to do something different for metadata.
>>
>> Another issue here is that video devices can be for video, for metadata, or for
>> both. So if is_io_mc is true, then you would get different behavior depending
>> on the type of video device: if it is just video, then it supports the INPUT
>> ioctls, if it supports metadata as well, then it doesn't.
>
> As expressed before, I think we really should drop VIDIOC_ENUMINPUT,
> VIDIOC_G_INPUT and VIDIOC_S_INPUT for devices that have V4L2_CAP_IO_MC
> set. They can't be supported by generic video node-centric applications
> that expect those ioctls to be supported in any case, so it makes little
> sense. With V4L2_CAP_IO_MC added, the v4l2-compliance tool can ignore
> those ioctls (or, even better, report an error if they're implemented).
I know your opinion on this, and I disagree. All non-MC video capture or output
devices support the input/output ioctls, and to suddenly make an exception is
not a good idea IMHO. On the other hand, I do agree that it makes no sense that
MC drivers would have to implement dummy ioctls. So having the core do this is,
I think, a good compromise.
In general I believe we should avoid introducing exceptions in the public API
unless there is no alternative. In this case there is a workable alternative
(dummy ioctls provided by the core).
Regards,
Hans
>
>> I would just keep this as it was originally:
>>
>> 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);
>>> + }
>>> 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);
>>> @@ -735,9 +742,15 @@ static void determine_valid_ioctls(struct video_device *vdev)
>>> SET_VALID_IOCTL(ops, VIDIOC_S_EDID, vidioc_s_edid);
>>> }
>>> 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);
>>> + if (is_io_mc && !is_meta) {
>>
>> Same here.
>>
>> The remainder of the series looks good (except that an additional cx18 patch is
>> needed as Andrey pointed out on irc).
>>
>>> + set_bit(_IOC_NR(VIDIOC_ENUMOUTPUT), valid_ioctls);
>>> + set_bit(_IOC_NR(VIDIOC_G_OUTPUT), valid_ioctls);
>>> + set_bit(_IOC_NR(VIDIOC_S_OUTPUT), valid_ioctls);
>>> + } else {
>>> + 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_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);
>>> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
>>> index b2ef8e60ea7da19d..afd1f427df557f71 100644
>>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
>>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
>>> @@ -1085,6 +1085,32 @@ 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)
>>> +{
>>> + struct video_device *vfd = video_devdata(file);
>>> +
>>> + if (vfd->device_caps & V4L2_CAP_IO_MC) {
>>> + *(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)
>>> +{
>>> + struct video_device *vfd = video_devdata(file);
>>> +
>>> + if (vfd->device_caps & V4L2_CAP_IO_MC) {
>>> + *(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 +1120,21 @@ static int v4l_s_input(const struct v4l2_ioctl_ops *ops,
>>> ret = v4l_enable_media_source(vfd);
>>> if (ret)
>>> return ret;
>>> +
>>> + if (vfd->device_caps & V4L2_CAP_IO_MC)
>>> + return *(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)
>>> {
>>> + struct video_device *vfd = video_devdata(file);
>>> +
>>> + if (vfd->device_caps & V4L2_CAP_IO_MC)
>>> + return *(int *)arg ? -EINVAL : 0;
>>> +
>>> return ops->vidioc_s_output(file, fh, *(unsigned int *)arg);
>>> }
>>>
>>> @@ -1143,6 +1178,14 @@ 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) {
>>> + if (p->index)
>>> + return -EINVAL;
>>> + strscpy(p->name, vfd->name, sizeof(p->name));
>>> + p->type = V4L2_INPUT_TYPE_CAMERA;
>>> + return 0;
>>> + }
>>> +
>>> return ops->vidioc_enum_input(file, fh, p);
>>> }
>>>
>>> @@ -1161,6 +1204,14 @@ 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) {
>>> + if (p->index)
>>> + return -EINVAL;
>>> + strscpy(p->name, vfd->name, sizeof(p->name));
>>> + p->type = V4L2_OUTPUT_TYPE_ANALOG;
>>> + return 0;
>>> + }
>>> +
>>> return ops->vidioc_enum_output(file, fh, p);
>>> }
>>>
>>> @@ -2683,10 +2734,8 @@ 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)
>>> @@ -2735,11 +2784,11 @@ 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 9817b7e2c968fd04..b18f3f7cde31c2e4 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 */
>>>
>>> /*
>
