Re: [PATCH v6 3/9] v4l: platform: Add Renesas CEU driver

Hans Verkuil
2018-01-19T12:25:53Z

On 01/19/18 13:20, Laurent Pinchart wrote:
> Hi Hans,
>
> On Friday, 19 January 2018 13:20:19 EET Hans Verkuil wrote:
>> On 01/16/18 22:44, Jacopo Mondi wrote:
>>> Add driver for Renesas Capture Engine Unit (CEU).
>>>
>>> The CEU interface supports capturing 'data' (YUV422) and 'images'
>>> (NV[12|21|16|61]).
>>>
>>> This driver aims to replace the soc_camera-based sh_mobile_ceu one.
>>>
>>> Tested with ov7670 camera sensor, providing YUYV_2X8 data on Renesas RZ
>>> platform GR-Peach.
>>>
>>> Tested with ov7725 camera sensor on SH4 platform Migo-R.
>>>
>>> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
>>> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>>> ---
>>>
>>> drivers/media/platform/Kconfig | 9 +
>>> drivers/media/platform/Makefile | 1 +
>>> drivers/media/platform/renesas-ceu.c | 1659 +++++++++++++++++++++++++++++
>>> 3 files changed, 1669 insertions(+)
>>> create mode 100644 drivers/media/platform/renesas-ceu.c
>
> [snip]
>
>>> diff --git a/drivers/media/platform/renesas-ceu.c
>>> b/drivers/media/platform/renesas-ceu.c new file mode 100644
>>> index 0000000..1b8f0ef
>>> --- /dev/null
>>> +++ b/drivers/media/platform/renesas-ceu.c
>
> [snip]
>
>>> +static void ceu_update_plane_sizes(struct v4l2_plane_pix_format *plane,
>>> + unsigned int bpl, unsigned int szimage)
>>> +{
>>> + if (plane->bytesperline < bpl)
>>> + plane->bytesperline = bpl;
>>> + if (plane->sizeimage < szimage)
>>> + plane->sizeimage = szimage;
>>
>> As mentioned in your cover letter, you do need to check for invalid
>> bytesperline values. The v4l2-compliance test is to see what happens
>> when userspace gives insane values, so yes, drivers need to be able
>> to handle that.
>
> What limit would you set, what is an acceptable large value versus an invalid
> large value ? I think we should have rules for this at the API level (or at
> least, if not part of the API, rules that are consistent across drivers).

I would expect this to be the max of what the hardware can support. If
that's really high, then this can be, say, 4 times the width.

Note that there are very few drivers that can handle a user-specified
stride.

>> plane->sizeimage is set by the driver, so drop the 'if' before the
>> assignment.
>
> I don't think that's correct. Userspace should be able to control padding
> lines at the end of the image, the same way it controls padding pixels at the
> end of lines.

If userspace wants larger buffers, then it should use VIDIOC_CREATE_BUFS.

sizeimage is exclusively set by the driver, applications rely on that.

>
>>> +}
>
> [snip]
>
>>> +static const struct v4l2_ioctl_ops ceu_ioctl_ops = {
>>> + .vidioc_querycap = ceu_querycap,
>>> +
>>> + .vidioc_enum_fmt_vid_cap_mplane = ceu_enum_fmt_vid_cap,
>>> + .vidioc_try_fmt_vid_cap_mplane = ceu_try_fmt_vid_cap,
>>> + .vidioc_s_fmt_vid_cap_mplane = ceu_s_fmt_vid_cap,
>>> + .vidioc_g_fmt_vid_cap_mplane = ceu_g_fmt_vid_cap,
>>> +
>>> + .vidioc_enum_input = ceu_enum_input,
>>> + .vidioc_g_input = ceu_g_input,
>>> + .vidioc_s_input = ceu_s_input,
>>> +
>>> + .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,
>>> +
>>> + .vidioc_g_parm = ceu_g_parm,
>>> + .vidioc_s_parm = ceu_s_parm,
>>> + .vidioc_enum_framesizes = ceu_enum_framesizes,
>>> + .vidioc_enum_frameintervals = ceu_enum_frameintervals,
>>
>> You're missing these ioctls:
>>
>> .vidioc_log_status = v4l2_ctrl_log_status,
>
> Is log status mandatory ?

No, but it doesn't hurt to add this one. It comes for free.

>
>> .vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
>> .vidioc_unsubscribe_event = v4l2_event_unsubscribe,
>>
>> These missing _event ops are the reason for this compliance failure:
>>
>> fail: v4l2-test-controls.cpp(782): subscribe event for control 'User
>> Controls' failed
>>> +};
>
> [snip]
>

Regards,

Hans