Re: [RFC PATCH 13/13] staging: vc04_services: Add a V4L2 M2M codec driver

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Hi,

Le dimanche 03 mars 2024 à 16:10 +0100, Maarten Vanraes a écrit :
> From: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> This adds a V4L2 memory to memory device that wraps the MMAL
> video decode and video_encode components for H264 and MJPEG encode
> and decode, MPEG4, H263, and VP8 decode (and MPEG2 decode
> if the appropriate licence has been purchased).
> 
> This patch squashes all the work done in developing the driver
> on the Raspberry Pi rpi-5.4.y kernel branch.
> Thanks to Kieran Bingham, Aman Gupta, Chen-Yu Tsai, and
> Marek Behún for their contributions. Please refer to the
> rpi-5.4.y branch for the full history.

It is really nice to see this RFC after all these years of downstream work. I
believe it will be nicer to just refer to your downstream tree and rewrite a
single commit message for the final submissions. As a companion information, we
ask all *new* drivers submitter to join a documented conformance tests result
(when the codec have a conformance suite publicly available). This can be placed
in the cover letter. We strongly suggest using Fluster from fluendo and
documenting the failires there. I believe it should not be a concern for this
driver, as my own tests on RPi4 seems to show very decent results downstream.
Reminder that the ISP based colorspace converison is faulty, and for conformance
it should be disabled (which is fine, as long as you mention it, so anyone else
can reproduce).


I'm not yet doing a full review, but you'll find some driver by general comments
below.

> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835-codec: Ensure OUTPUT timestamps are always forwarded
> 
> The firmware by default tries to ensure that decoded frame
> timestamps always increment. This is counter to the V4L2 API
> which wants exactly the OUTPUT queue timestamps passed to the
> CAPTURE queue buffers.
> 
> Disable the firmware option.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/vc04_services/codec: Add support for CID MPEG_HEADER_MODE
> 
> Control V4L2_CID_MPEG_VIDEO_HEADER_MODE controls whether the encoder
> is meant to emit the header bytes as a separate packet or with the
> first encoded frame.
> Add support for it.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/vc04_services/codec: Clear last buf dequeued flag on START
> 
> It appears that the V4L2 M2M framework requires the driver to manually
> call vb2_clear_last_buffer_dequeued on the CAPTURE queue during a
> V4L2_DEC_CMD_START.
> Add such a call.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/vc04-services/codec: Fix logical precedence issue
> 
> Two issues identified with operator precedence in logical
> expressions. Fix them.
> 
> https://github.com/raspberrypi/linux/issues/4040
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> vc04_services: bcm2835-codec: Switch to s32fract
> 
> staging/bcm2835-codec: Add the unpacked (16bpp) raw formats
> 
> Now that the firmware supports the unpacked (16bpp) variants
> of the MIPI raw formats, add the mappings.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835-codec: Log the number of excess supported formats
> 
> When logging that the firmware has provided more supported formats
> than we had allocated storage for, log the number allocated and
> returned.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835-codec: Add support for pixel aspect ratio
> 
> If the format is detected by the driver and a V4L2_EVENT_SOURCE_CHANGE
> event is generated, then pass on the pixel aspect ratio as well.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835-codec: Implement additional g_selection calls for decode
> 
> v4l_cropcap calls our vidioc_g_pixelaspect function to get the pixel
> aspect ratio, but also calls g_selection for V4L2_SEL_TGT_CROP_BOUNDS
> and V4L2_SEL_TGT_CROP_DEFAULT. Whilst it allows for vidioc_g_pixelaspect
> not to be implemented, it doesn't allow for either of the other two.
> 
> Add in support for the additional selection targets.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835-codec: Add VC-1 support.
> 
> Providing the relevant licence has been purchased, then Pi0-3
> can decode VC-1.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835-codec: Fix support for levels 4.1 and 4.2
> 
> The driver said it supported H264 levels 4.1 and 4.2, but
> was missing the V4L2 to MMAL mappings.
> 
> Add in those mappings.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835-codec: Set the colourspace appropriately for RGB formats
> 
> Video decode supports YUV and RGB formats. YUV needs to report SMPTE170M
> or REC709 appropriately, whilst RGB should report SRGB.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835-codec: Pass corrupt frame flag.
> 
> MMAL has the flag MMAL_BUFFER_HEADER_FLAG_CORRUPTED but that
> wasn't being passed through, so add it.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835-codec: Do not update crop from S_FMT after res change
> 
> During decode, setting the CAPTURE queue format was setting the crop
> rectangle to the requested height before aligning up the format to
> cater for simple clients that weren't expecting to deal with cropping
> and the SELECTION API.
> This caused problems on some resolution change events if the client
> didn't also then use the selection API.
> 
> Disable the crop update after a resolution change.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> bcm2835: Allow compressed frames to set sizeimage (#4386)
> 
> Allow the user to set sizeimage in TRY_FMT and S_FMT if the format
> flags have V4L2_FMT_FLAG_COMPRESSED set
> 
> Signed-off-by: John Cox <jc@xxxxxxxxxxxxx>
> 
> staging/bcm2835-codec: Change the default codec res to 32x32
> 
> In order to effectively guarantee that a V4L2_EVENT_SOURCE_CHANGE
> event occurs, adopt a default resolution of 32x32 so that it
> is incredibly unlikely to be decoding a stream of that resolution
> and therefore failing to note a "change" requiring the event.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835-codec: Add support for decoding interlaced streams
> 
> The video decoder can support decoding interlaced streams, so add
> the required plumbing to signal this correctly.
> 
> The encoder and ISP do NOT support interlaced data, so trying to
> configure an interlaced format on those nodes will be rejected.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835-codec: Correct ENUM_FRAMESIZES stepsize to 2
> 
> Being YUV420 formats, the step size is always 2 to avoid part
> chroma subsampling.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835-codec: Return buffers to QUEUED not ERROR state
> 
> Should start_streaming fail, or buffers be queued during
> stop_streaming, they should be returned to the core as QUEUED
> and not (as currently) as ERROR.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835_codec: Log MMAL flags in hex
> 
> The flags is a bitmask, so it's far easier to interpret as hex
> data instead of decimal.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging: bcm2835-codec: Allow custom specified strides/bytesperline.
> 
> If the client provides a bytesperline value in try_fmt/s_fmt then
> validate it and correct if necessary.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835_codec: Add support for image_fx to deinterlace
> 
> Adds another /dev/video node wrapping image_fx doing deinterlace.
> 
> Co-developed-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> Signed-off-by: Dom Cobley <popcornmix@xxxxxxxxx>
> 
> staging/bcm2835-v4l2_codec: Fix for encode selection API
> 
> Matches correct behaviour from DECODE and DEINTERLACE
> 
> Signed-off-by: Dom Cobley <popcornmix@xxxxxxxxx>
> 
> staging: bcm2835-codec: Allow decode res changed before STREAMON(CAPTURE)
> 
> The V4L2 stateful video decoder API requires that you can STREAMON
> on only the OUTPUT queue, feed in buffers, and wait for the
> SOURCE_CHANGE event.
> This requires that we enable the MMAL output port at the same time
> as the input port, because the output port is the one that creates
> the SOURCE_CHANGED event.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835-codec: Do not send buffers to the VPU unless streaming
> 
> With video decode we now enable both input and output ports on
> the component. This means that buffers will get passed to the VPU
> earlier than desired if they are queued befoer STREAMON.
> 
> Check that the queue is streaming before sending buffers to the VPU.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging: bcm2835-codec: Format changed should trigger drain
> 
> When a format changed event occurs, the spec says that it
> triggers an implicit drain, and that needs to be signalled
> via -EPIPE.
> 
> For BCM2835, the format changed event happens at the point
> the format change occurs, so no further buffers exist from
> before the resolution changed point. We therefore signal the
> last buffer immediately.
> We don't have a V4L2 available to us at this point, so set
> the videobuf2 queue last_buffer_dequeued flag directly.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging: bcm2835-codec: Signal the firmware to stop on all changes
> 
> The firmware defaults to not stopping video decode if only the
> pixel aspect ratio or colourspace change. V4L2 requires us
> to stop decoding on any change, therefore tell the firmware
> of the desire for this alternate behaviour.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging: bcm2835-codec: Queue flushed buffers instead of completing
> 
> When a buffer is returned on a port that is disabled, return it
> to the videobuf2 QUEUED state instead of DONE which returns it
> to the client.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging: bcm2835_codec: Correct flushing code for refcounting
> 
> Completions don't reference count, so setting the completion
> on the first buffer returned and then not reinitialising it
> means that the flush function doesn't behave as intended.
> 
> Signal the completion when the last buffer is returned.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging: bcm2835-codec: Ensure all ctrls are set on streamon
> 
> Currently the code was only setting some controls from
> bcm2835_codec_set_ctrls, but it's simpler to use
> v4l2_ctrl_handler_setup to avoid forgetting to adding new
> controls to the list.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging: bcm2835-codec: Add support for H&V Flips to ISP
> 
> The ISP can do H & V flips whilst resizing or converting
> the image, so expose that via V4L2_CID_[H|V]FLIP.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> bcm2835-v4l2-codec: Remove advertised support of VP8
> 
> The support for this format by firmware is very limited
> and won't be faster than the arm.
> 
> Signed-off-by: Dom Cobley <popcornmix@xxxxxxxxx>
> 
> Pass V4L2_CID_MPEG_VIDEO_H264_MIN_QP/MAX_QP to bcm2835-v4l2-codec
> 
> Following raspberrypi/linux#4704. This is necessary to set up
> quantization for variable bitrate to avoid video flickering.
> 
> staging/bcm2835-codec: bytesperline for YUV420/YVU420 needs to be 64
> 
> Matching https://github.com/raspberrypi/linux/pull/4419, the ISP
> block (which is also used on the input of the encoder, and output
> of the decoder) needs the base address of all planes to be aligned
> to multiples of 32. This includes the chroma planes of YUV420 and
> YVU420.
> If the height is only a multiple of 2 (not 4), then you get an odd
> number of lines in the second plane, which means the 3rd plane
> starts at a multiple of bytesperline/2.
> 
> Set the minimum bytesperline alignment to 64 for those formats
> so that the plane alignment is always right.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging/bcm2835-codec: Allow a different stride alignment per role
> 
> Deinterlace and decode aren't affected in the same way as encode
> and ISP by the alignment requirement on 3 plane YUV420.
> Decode would be affected, but it always aligns the height up to
> a macroblock, and uses the selection API to reflect that.
> 
> Add in the facility to set the bytesperline alignment per role.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging: vc04_services: codec: Add support for V4L2_PIX_FMT_RGBA32 format
> 
> We already support V4L2_PIX_FMT_BGR32 which is the same thing with red
> and blue swapped, so it makes sense to include this variant as well.
> 
> Signed-off-by: David Plowman <david.plowman@xxxxxxxxxxxxxxx>
> 
> bcm2835-codec: Return empty buffers to the VPU instead of queueing to vbuf2
> 
> The encoder can skip frames totally should rate control overshoot
> the target bitrate too far. In this situation it generates an
> output buffer of length 0.
> V4L2 treats a buffer of length 0 as an end of stream flag, which is
> not appropriate in this case, therefore we can not return that buffer
> to the client.
> 
> The driver was returning the buffer to videobuf2 in the QUEUED state,
> however that buffer was then not dequeued again, so the number of
> buffers was reduced each time this happened. In the pathological
> case of using GStreamer's videotestsrc in mode 1 for noise, this happens
> sufficiently frequently to totally stall the pipeline.
> 
> If the port is still enabled then return the buffer straight back to
> the VPU rather than to videobuf2.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> vc04_services: bcm2835-codec: Add support for V4L2_PIX_FMT_NV12_COL128
> 
> V4L2_PIX_FMT_NV12_COL128 is supported by the ISP and the input of
> video_encode, output of video_decode, and both input and output
> of the ISP.
> 
> Add in the plumbing to support the format on those ports.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> vc04_services: bcm2835-codec: Set crop_height for compressed formats
> 
> In particular for the encoder where the CAPTURE format dictates
> the parameters given to the codec we need to be able to set the
> value passed as the crop_height for the compressed format.
> There's no crop available for cropped modes, so always set
> crop_height to the requested height.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> vc04_services: bcm2835-codec: Set port format from s_selection
> 
> s_selection allows the crop region of an uncompressed pixel
> format to be specified, but it wasn't passing the setting on to
> the firmware. Depending on call order this would potentially
> mean that the crop wasn't actioned.
> 
> Set the port format on s_selection if we have a component created.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> bcm2835-codec: /dev/video31 as interface to image_encode JPEG encoder
> 
> Signed-off-by: Maxim Devaev <mdevaev@xxxxxxxxx>
> 
> bcm2835-v4l2-codec: support H.264 5.0 and 5.1 levels
> 
> vc04_services: bcm2835-codec:  Remove redundant role check
> 
> vidioc_try_encoder_cmd checks the role, but the ioctl is disabled
> for any roles in which it is invalid.
> 
> Remove the redundant check.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> vc04_services: bcm2835-codec: Allow encoder_cmd on ISP and deinterlace
> 
> ISP and deinterlace also need a mechanism for passing effectively
> an EOS through the pipeline to signal when all buffers have been
> processed.
> 
> VIDIOC_ENCODER_CMD does exactly this for encoders, so reuse the same
> function for ISP and deinterlace.
> (VIDIOC_DECODER_CMD is slightly different in that it also passes
> details of when and how to stop, so is not as relevant).
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> vc04_services: bcm2835_codec: Allow larger images through the ISP
> 
> Whilst the codecs are restricted to 1920x1080 / 1080x1920, the ISP
> isn't, but the limits advertised via V4L2 was 1920x1920 for all
> roles.
> 
> Increase the limit to 16k x 16k for the ISP.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> media: bcm2835-v4l2-codec: Enable selection ioctl for ISP
> 
> The ISP cases do nothing. Remove the break that separates them from the
> deinterlace case so they now do the same as deinterlace. This enables
> simple width & height setting, but does not enable setting left and
> top coordinates.
> 
> Signed-off-by: John Cox <jc@xxxxxxxxxxxxx>
> 
> media: bcm2835-v4l2-codec: Add profile & level ctrls to decode
> 
> In order to support discovery of what profile & levels are supported by
> stateful decoders implement the profile and level controls where they
> are defined by V4L2.
> 
> Signed-off-by: John Cox <jc@xxxxxxxxxxxxx>
> 
> vc04_services: bcm2835_codec: Ignore READ_ONLY ctrls in s_ctrl
> 
> In adding the MPEG2/MPEG4/H264 level and profile controls to
> the decoder, they weren't declared as read-only, nor handlers
> added to bcm2835_codec_s_ctrl. That resulted in an error message
> "Invalid control" being logged every time v4l2_ctrl_handler_setup
> was called from bcm2835_codec_create_component.
> 
> Define those controls as read only, and exit early from s_ctrl
> on read only controls.
> 
> Fixes: "media: bcm2835-v4l2-codec: Add profile & level ctrls to decode"
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> vc04_services: bcm2835_codec: Set MPEG2_LEVEL control to READ_ONLY
> 
> V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL  was missed from
> "vc04_services: bcm2835_codec: Ignore READ_ONLY ctrls in s_ctrl"
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging: bcm2835-codec: Add V4L2_CID_MPEG_VIDEO_B_FRAMES control
> 
> FFmpeg insists on trying to set V4L2_CID_MPEG_VIDEO_B_FRAMES to
> 0, and generates an error should it fail.
> As our encoder doesn't support B frames, add a stub handler for
> it to silence FFmpeg.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging: bcm2835-codec: Add support for V4L2_CID_MPEG_VIDEO_GOP_SIZE
> 
> For H264, V4L2_CID_MPEG_VIDEO_H264_I_PERIOD is meant to be the intra
> I-frame period, whilst V4L2_CID_MPEG_VIDEO_GOP_SIZE is the intra IDR
> frame period.
> The firmware encoder doesn't produce I-frames that aren't IDR as well,
> therefore V4L2_CID_MPEG_VIDEO_GOP_SIZE is technically the correct
> control, however users may have adopted V4L2_CID_MPEG_VIDEO_H264_I_PERIOD.
> 
> Add support for V4L2_CID_MPEG_VIDEO_GOP_SIZE controlling the encoder,
> and have VIDIOC_S_CTRL for V4L2_CID_MPEG_VIDEO_H264_I_PERIOD update
> the value for V4L2_CID_MPEG_VIDEO_GOP_SIZE (the reverse is not
> implemented).
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging: bcm2835-codec: Add missing alignment for V4L2_PIX_FMT_RGBA32
> 
> The patch adding image encode (JPEG) to the driver missed adding
> the alignment constraint for V4L2_PIX_FMT_RGBA32, which meant
> it ended up giving a stride and size of 0.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> vc04_services: bcm2835-codec: Correct alignment requirements for YUYV
> 
> The firmware wants the YUYV format stride alignment to be to a multiple
> of 32pixels / 64 bytes. The kernel driver was configuring it to a multiple
> of 16 pixels / 32 bytes, which then failed when it tried starting to
> stream.
> 
> Correct the alignment requirements.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> 
> staging: vchiq_arm: Register bcm2835-codec as a platform driver
> 
> Following the same pattern as bcm2835-camera and bcm2835-audio,
> register the V4L2 codec driver as a platform driver
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> Signed-off-by: Maarten Vanraes <maarten@xxxxxxxx>
> ---
>  drivers/staging/vc04_services/Kconfig         |    2 +
>  drivers/staging/vc04_services/Makefile        |    2 +
>  .../vc04_services/bcm2835-codec/Kconfig       |   11 +
>  .../vc04_services/bcm2835-codec/Makefile      |    5 +
>  .../bcm2835-codec/bcm2835-v4l2-codec.c        | 3973 +++++++++++++++++
>  .../interface/vchiq_arm/vchiq_arm.c           |    3 +
>  .../vchiq-mmal/mmal-parameters.h              |    8 +
>  7 files changed, 4004 insertions(+)
>  create mode 100644 drivers/staging/vc04_services/bcm2835-codec/Kconfig
>  create mode 100644 drivers/staging/vc04_services/bcm2835-codec/Makefile
>  create mode 100644 drivers/staging/vc04_services/bcm2835-codec/bcm2835-v4l2-codec.c
> 
> diff --git a/drivers/staging/vc04_services/Kconfig b/drivers/staging/vc04_services/Kconfig
> index e71e5a8b820a..568880ca9760 100644
> --- a/drivers/staging/vc04_services/Kconfig
> +++ b/drivers/staging/vc04_services/Kconfig
> @@ -44,6 +44,8 @@ source "drivers/staging/vc04_services/bcm2835-audio/Kconfig"
>  
>  source "drivers/staging/vc04_services/bcm2835-camera/Kconfig"
>  
> +source "drivers/staging/vc04_services/bcm2835-codec/Kconfig"
> +
>  source "drivers/staging/vc04_services/bcm2835-isp/Kconfig"
>  
>  source "drivers/staging/vc04_services/vchiq-mmal/Kconfig"
> diff --git a/drivers/staging/vc04_services/Makefile b/drivers/staging/vc04_services/Makefile
> index 2cebf92525a0..903c949a1ee5 100644
> --- a/drivers/staging/vc04_services/Makefile
> +++ b/drivers/staging/vc04_services/Makefile
> @@ -14,6 +14,8 @@ endif
>  
>  obj-$(CONFIG_SND_BCM2835)		+= bcm2835-audio/
>  obj-$(CONFIG_VIDEO_BCM2835)		+= bcm2835-camera/
> +obj-$(CONFIG_VIDEO_CODEC_BCM2835)	+= bcm2835-codec/
>  obj-$(CONFIG_BCM2835_VCHIQ_MMAL)	+= vchiq-mmal/
>  obj-$(CONFIG_BCM_VC_SM_CMA)		+= vc-sm-cma/
>  obj-$(CONFIG_VIDEO_ISP_BCM2835) 	+= bcm2835-isp/
> +
> diff --git a/drivers/staging/vc04_services/bcm2835-codec/Kconfig b/drivers/staging/vc04_services/bcm2835-codec/Kconfig
> new file mode 100644
> index 000000000000..761c8ba4b40f
> --- /dev/null
> +++ b/drivers/staging/vc04_services/bcm2835-codec/Kconfig
> @@ -0,0 +1,11 @@
> +config VIDEO_CODEC_BCM2835
> +	tristate "BCM2835 Video codec support"
> +	depends on MEDIA_SUPPORT && MEDIA_CONTROLLER
> +	depends on VIDEO_DEV && (ARCH_BCM2835 || COMPILE_TEST)
> +	select BCM2835_VCHIQ_MMAL
> +	select VIDEOBUF2_DMA_CONTIG
> +	select V4L2_MEM2MEM_DEV
> +	help
> +	  Say Y here to enable the V4L2 video codecs for
> +	  Broadcom BCM2835 SoC. This operates over the VCHIQ interface
> +	  to a service running on VideoCore.
> diff --git a/drivers/staging/vc04_services/bcm2835-codec/Makefile b/drivers/staging/vc04_services/bcm2835-codec/Makefile
> new file mode 100644
> index 000000000000..0efc20181aaf
> --- /dev/null
> +++ b/drivers/staging/vc04_services/bcm2835-codec/Makefile
> @@ -0,0 +1,5 @@
> +# SPDX-License-Identifier: GPL-2.0
> +bcm2835-codec-objs := bcm2835-v4l2-codec.o
> +
> +obj-$(CONFIG_VIDEO_CODEC_BCM2835) += bcm2835-codec.o
> +
> diff --git a/drivers/staging/vc04_services/bcm2835-codec/bcm2835-v4l2-codec.c b/drivers/staging/vc04_services/bcm2835-codec/bcm2835-v4l2-codec.c
> new file mode 100644
> index 000000000000..a76e198102fa
> --- /dev/null
> +++ b/drivers/staging/vc04_services/bcm2835-codec/bcm2835-v4l2-codec.c
> @@ -0,0 +1,3973 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +/*
> + * A v4l2-mem2mem device that wraps the video codec MMAL component.
> + *
> + * Copyright 2018 Raspberry Pi (Trading) Ltd.
> + * Author: Dave Stevenson (dave.stevenson@xxxxxxxxxxxxxxx)
> + *
> + * Loosely based on the vim2m virtual driver by Pawel Osciak
> + * Copyright (c) 2009-2010 Samsung Electronics Co., Ltd.
> + * Pawel Osciak, <pawel@xxxxxxxxxx>
> + * Marek Szyprowski, <m.szyprowski@xxxxxxxxxxx>
> + *
> + * Whilst this driver uses the v4l2_mem2mem framework, it does not need the
> + * scheduling aspects, so will always take the buffers, pass them to the VPU,
> + * and then signal the job as complete.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2 of the
> + * License, or (at your option) any later version
> + */
> +#include <linux/module.h>
> +#include <linux/delay.h>
> +#include <linux/fs.h>
> +#include <linux/timer.h>
> +#include <linux/sched.h>
> +#include <linux/syscalls.h>
> +
> +#include <media/v4l2-mem2mem.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-ioctl.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-event.h>
> +#include <media/videobuf2-dma-contig.h>
> +
> +#include "../vchiq-mmal/mmal-encodings.h"
> +#include "../vchiq-mmal/mmal-msg.h"
> +#include "../vchiq-mmal/mmal-parameters.h"
> +#include "../vchiq-mmal/mmal-vchiq.h"
> +
> +#include "../vc-sm-cma/vc_sm_knl.h"
> +
> +#include "../interface/vchiq_arm/vchiq_bus.h"
> +
> +MODULE_IMPORT_NS(DMA_BUF);
> +
> +/*
> + * Default /dev/videoN node numbers for decode and encode.
> + * Deliberately avoid the very low numbers as these are often taken by webcams
> + * etc, and simple apps tend to only go for /dev/video0.
> + */
> +static int decode_video_nr = 10;
> +module_param(decode_video_nr, int, 0644);
> +MODULE_PARM_DESC(decode_video_nr, "decoder video device number");
> +
> +static int encode_video_nr = 11;
> +module_param(encode_video_nr, int, 0644);
> +MODULE_PARM_DESC(encode_video_nr, "encoder video device number");
> +
> +static int isp_video_nr = 12;
> +module_param(isp_video_nr, int, 0644);
> +MODULE_PARM_DESC(isp_video_nr, "isp video device number");
> +
> +static int deinterlace_video_nr = 18;
> +module_param(deinterlace_video_nr, int, 0644);
> +MODULE_PARM_DESC(deinterlace_video_nr, "deinterlace video device number");
> +
> +static int encode_image_nr = 31;
> +module_param(encode_image_nr, int, 0644);
> +MODULE_PARM_DESC(encode_image_nr, "encoder image device number");

I'd drop this from upstream submission.

> +
> +/*
> + * Workaround for GStreamer v4l2convert component not considering Bayer formats
> + * as raw, and therefore not considering a V4L2 device that supports them as
> + * a suitable candidate.
> + */
> +static bool disable_bayer;
> +module_param(disable_bayer, bool, 0644);
> +MODULE_PARM_DESC(disable_bayer, "Disable support for Bayer formats");
> 

I'd drop this too, you can work with upstream GStreamer maintainers to fix this
issue instead (someone like me ?). I believe there is a pending (and aging) MR
from Mauro actually to address this, and some smaller parts have been rewritten
and merged meanwhile, so this issue might not even exist anymore.

> +
> +static unsigned int debug;
> +module_param(debug, uint, 0644);
> +MODULE_PARM_DESC(debug, "activates debug info (0-3)");
> 

Other V4L2 drivers uses a sysfs dev_debug file to turn on/off logging. The
logging can also be fine tuned with dynamic debug. 

> +
> +static bool advanced_deinterlace = true;
> +module_param(advanced_deinterlace, bool, 0644);
> +MODULE_PARM_DESC(advanced_deinterlace, "Use advanced deinterlace");
> +
> +static int field_override;
> +module_param(field_override, int, 0644);
> +MODULE_PARM_DESC(field_override, "force TB(8)/BT(9) field");

I'd drop this one too. If the driver can force a specific field order regardless
the input data, I'd suggest working on a control instead.

> +
> +enum bcm2835_codec_role {
> +	DECODE,
> +	ENCODE,
> +	ISP,
> +	DEINTERLACE,
> +	ENCODE_IMAGE,
> +	NUM_ROLES
> +};

I believe the organization or naming of the drive can be improved. Only 2/5
roles falls into the "CODEC" category. If you are making 5 drivers with shared
code, I'd split shared code properly, and submit these in their own commits.

> +
> +static const char * const roles[] = {
> +	"decode",
> +	"encode",
> +	"isp",
> +	"image_fx",
> +	"encode_image",
> +};
> +
> +static const char * const components[] = {
> +	"ril.video_decode",
> +	"ril.video_encode",
> +	"ril.isp",
> +	"ril.image_fx",
> +	"ril.image_encode",
> +};
> +
> +/* Timeout for stop_streaming to allow all buffers to return */
> +#define COMPLETE_TIMEOUT (2 * HZ)
> +
> +#define MIN_W		32
> +#define MIN_H		32
> +#define MAX_W_CODEC	1920
> +#define MAX_H_CODEC	1920
> +#define MAX_W_ISP	16384
> +#define MAX_H_ISP	16384
> +#define BPL_ALIGN	32
> +/*
> + * The decoder spec supports the V4L2_EVENT_SOURCE_CHANGE event, but the docs
> + * seem to want it to always be generated on startup, which prevents the client
> + * from configuring the CAPTURE queue based on any parsing it has already done
> + * which may save time and allow allocation of CAPTURE buffers early. Surely
> + * SOURCE_CHANGE means something has changed, not just "always notify".

Please don't try and bug report the spec in your code. In fact, this
interpretation of the spec is incorrect. If userspace have allocated and called
STREAMON on the capture queue, the source change event can safely be skipped.
The issue you had downstream was that the decision was only made based on the
format initialized from the OUTPUT queue format (indirect format setting). As a
side effect, userspace that did not want to risk having to allocate twice the
buffers, but did hint the width/height in the OUTPUT queue format could not
work.

> + *
> + * For those clients that don't set the CAPTURE resolution, adopt a default
> + * resolution that is seriously unlikely to be correct, therefore almost
> + * guaranteed to get the SOURCE_CHANGE event.
> + */
> +#define DEFAULT_WIDTH	32
> +#define DEFAULT_HEIGHT	32

You have to set a default format, this is mandated by the spec. Now, that format
should be updated if the client hint the display resolution (or even coded
resolution) in S_FMT(OUTPUT). In any case, it should not interfere with the
decision to sent SOURCE_CHANGE. If the CAPTURE queue is not configure, you send
SOURCE_CHANGE always (basically asking userspace to configure the queue),
otherwise you can send only if needed.

> +/*
> + * The unanswered question - what is the maximum size of a compressed frame?
> + * V4L2 mandates that the encoded frame must fit in a single buffer. Sizing
> + * that buffer is a compromise between wasting memory and risking not fitting.
> + * The 1080P version of Big Buck Bunny has some frames that exceed 512kB.
> + * Adopt a moderately arbitrary split at 720P for switching between 512 and
> + * 768kB buffers.
> + */
> +#define DEF_COMP_BUF_SIZE_GREATER_720P	(768 << 10)
> +#define DEF_COMP_BUF_SIZE_720P_OR_LESS	(512 << 10)

Your buffer size seems rather small by default (note that you should also accept
bigger size if userspace asked for it). In general though, this issue is true
for all drivers, we should certainly generalized this into v4l2-common at some
point, but its not your fault if it wasn't done yet, so not really needed.

> +/* JPEG image can be very large. For paranoid reasons 4MB is used */
> +#define DEF_COMP_BUF_SIZE_JPEG (4096 << 10)
> +
> +/* Flags that indicate a format can be used for capture/output */
> +#define MEM2MEM_CAPTURE		BIT(0)
> +#define MEM2MEM_OUTPUT		BIT(1)
> +
> +#define BCM2835_V4L_CODEC_NAME	"bcm2835-codec"
> +#define MEM2MEM_NAME		"bcm2835-codec"
> +
> +struct bcm2835_codec_fmt {
> +	u32	fourcc;
> +	int	depth;
> +	u8	bytesperline_align[NUM_ROLES];
> +	u32	flags;
> +	u32	mmal_fmt;
> +	int	size_multiplier_x2;
> +	bool	is_bayer;
> +};

For this and your following configuration structure, it would be nice to see if
you could make use of the v4l2-common. If the firmware is calculating the buffer
size, I'd say this is not important, but if the kernel driver is calculating it,
it would be much safer to keep this in one place. Broken stride and buffer size
calculation are unfortunately too common, and unavoidably cause security
concerns.

> +
> +static const struct bcm2835_codec_fmt supported_formats[] = {
> +	{
> +		/* YUV formats */
> +		.fourcc			= V4L2_PIX_FMT_YUV420,
> +		.depth			= 8,
> +		.bytesperline_align	= { 32, 64, 64, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_I420,
> +		.size_multiplier_x2	= 3,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_YVU420,
> +		.depth			= 8,
> +		.bytesperline_align	= { 32, 64, 64, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_YV12,
> +		.size_multiplier_x2	= 3,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_NV12,
> +		.depth			= 8,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_NV12,
> +		.size_multiplier_x2	= 3,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_NV21,
> +		.depth			= 8,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_NV21,
> +		.size_multiplier_x2	= 3,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_RGB565,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_RGB16,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_YUYV,
> +		.depth			= 16,
> +		.bytesperline_align	= { 64, 64, 64, 64, 64 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_YUYV,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_UYVY,
> +		.depth			= 16,
> +		.bytesperline_align	= { 64, 64, 64, 64, 64 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_UYVY,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_YVYU,
> +		.depth			= 16,
> +		.bytesperline_align	= { 64, 64, 64, 64, 64 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_YVYU,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_VYUY,
> +		.depth			= 16,
> +		.bytesperline_align	= { 64, 64, 64, 64, 64 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_VYUY,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_NV12_COL128,
> +		.depth			= 8,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_YUVUV128,
> +		.size_multiplier_x2	= 3,
> +	}, {
> +		/* RGB formats */
> +		.fourcc			= V4L2_PIX_FMT_RGB24,
> +		.depth			= 24,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_RGB24,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_BGR24,
> +		.depth			= 24,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BGR24,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_BGR32,
> +		.depth			= 32,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BGRA,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_RGBA32,
> +		.depth			= 32,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_RGBA,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		/* Bayer formats */
> +		/* 8 bit */
> +		.fourcc			= V4L2_PIX_FMT_SRGGB8,
> +		.depth			= 8,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SRGGB8,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SBGGR8,
> +		.depth			= 8,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SBGGR8,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGRBG8,
> +		.depth			= 8,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGRBG8,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGBRG8,
> +		.depth			= 8,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGBRG8,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		/* 10 bit */
> +		.fourcc			= V4L2_PIX_FMT_SRGGB10P,
> +		.depth			= 10,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SRGGB10P,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SBGGR10P,
> +		.depth			= 10,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SBGGR10P,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGRBG10P,
> +		.depth			= 10,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGRBG10P,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGBRG10P,
> +		.depth			= 10,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGBRG10P,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		/* 12 bit */
> +		.fourcc			= V4L2_PIX_FMT_SRGGB12P,
> +		.depth			= 12,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SRGGB12P,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SBGGR12P,
> +		.depth			= 12,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SBGGR12P,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGRBG12P,
> +		.depth			= 12,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGRBG12P,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGBRG12P,
> +		.depth			= 12,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGBRG12P,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		/* 14 bit */
> +		.fourcc			= V4L2_PIX_FMT_SRGGB14P,
> +		.depth			= 14,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SRGGB14P,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SBGGR14P,
> +		.depth			= 14,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SBGGR14P,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGRBG14P,
> +		.depth			= 14,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGRBG14P,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGBRG14P,
> +		.depth			= 14,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGBRG14P,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		/* 16 bit */
> +		.fourcc			= V4L2_PIX_FMT_SRGGB16,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SRGGB16,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SBGGR16,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SBGGR16,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGRBG16,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGRBG16,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGBRG16,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGBRG16,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		/* Bayer formats unpacked to 16bpp */
> +		/* 10 bit */
> +		.fourcc			= V4L2_PIX_FMT_SRGGB10,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SRGGB10,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SBGGR10,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SBGGR10,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGRBG10,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGRBG10,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGBRG10,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGBRG10,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		/* 12 bit */
> +		.fourcc			= V4L2_PIX_FMT_SRGGB12,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SRGGB12,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SBGGR12,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SBGGR12,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGRBG12,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGRBG12,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGBRG12,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGBRG12,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		/* 14 bit */
> +		.fourcc			= V4L2_PIX_FMT_SRGGB14,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SRGGB14,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SBGGR14,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SBGGR14,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGRBG14,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGRBG14,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_SGBRG14,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_BAYER_SGBRG14,
> +		.size_multiplier_x2	= 2,
> +		.is_bayer		= true,
> +	}, {
> +		/* Monochrome MIPI formats */
> +		/* 8 bit */
> +		.fourcc			= V4L2_PIX_FMT_GREY,
> +		.depth			= 8,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_GREY,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		/* 10 bit */
> +		.fourcc			= V4L2_PIX_FMT_Y10P,
> +		.depth			= 10,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_Y10P,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		/* 12 bit */
> +		.fourcc			= V4L2_PIX_FMT_Y12P,
> +		.depth			= 12,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_Y12P,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		/* 14 bit */
> +		.fourcc			= V4L2_PIX_FMT_Y14P,
> +		.depth			= 14,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_Y14P,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		/* 16 bit */
> +		.fourcc			= V4L2_PIX_FMT_Y16,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_Y16,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		/* 10 bit as 16bpp */
> +		.fourcc			= V4L2_PIX_FMT_Y10,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_Y10,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		/* 12 bit as 16bpp */
> +		.fourcc			= V4L2_PIX_FMT_Y12,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_Y12,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		/* 14 bit as 16bpp */
> +		.fourcc			= V4L2_PIX_FMT_Y14,
> +		.depth			= 16,
> +		.bytesperline_align	= { 32, 32, 32, 32, 32 },
> +		.flags			= 0,
> +		.mmal_fmt		= MMAL_ENCODING_Y14,
> +		.size_multiplier_x2	= 2,
> +	}, {
> +		/* Compressed formats */
> +		.fourcc			= V4L2_PIX_FMT_H264,
> +		.depth			= 0,
> +		.flags			= V4L2_FMT_FLAG_COMPRESSED,
> +		.mmal_fmt		= MMAL_ENCODING_H264,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_JPEG,
> +		.depth			= 0,
> +		.flags			= V4L2_FMT_FLAG_COMPRESSED,
> +		.mmal_fmt		= MMAL_ENCODING_JPEG,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_MJPEG,
> +		.depth			= 0,
> +		.flags			= V4L2_FMT_FLAG_COMPRESSED,
> +		.mmal_fmt		= MMAL_ENCODING_MJPEG,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_MPEG4,
> +		.depth			= 0,
> +		.flags			= V4L2_FMT_FLAG_COMPRESSED,
> +		.mmal_fmt		= MMAL_ENCODING_MP4V,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_H263,
> +		.depth			= 0,
> +		.flags			= V4L2_FMT_FLAG_COMPRESSED,
> +		.mmal_fmt		= MMAL_ENCODING_H263,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_MPEG2,
> +		.depth			= 0,
> +		.flags			= V4L2_FMT_FLAG_COMPRESSED,
> +		.mmal_fmt		= MMAL_ENCODING_MP2V,
> +	}, {
> +		.fourcc			= V4L2_PIX_FMT_VC1_ANNEX_G,
> +		.depth			= 0,
> +		.flags			= V4L2_FMT_FLAG_COMPRESSED,
> +		.mmal_fmt		= MMAL_ENCODING_WVC1,
> +	}
> +};
> +
> +struct bcm2835_codec_fmt_list {
> +	struct bcm2835_codec_fmt *list;
> +	unsigned int num_entries;
> +};
> +
> +struct m2m_mmal_buffer {
> +	struct v4l2_m2m_buffer	m2m;
> +	struct mmal_buffer	mmal;
> +};
> +
> +/* Per-queue, driver-specific private data */
> +struct bcm2835_codec_q_data {
> +	/*
> +	 * These parameters should be treated as gospel, with everything else
> +	 * being determined from them.
> +	 */
> +	/* Buffer width/height */
> +	unsigned int		bytesperline;
> +	unsigned int		height;
> +	/* Crop size used for selection handling */
> +	unsigned int		crop_width;
> +	unsigned int		crop_height;
> +	bool			selection_set;
> +	struct v4l2_fract	aspect_ratio;
> +	enum v4l2_field		field;
> +
> +	unsigned int		sizeimage;
> +	unsigned int		sequence;
> +	struct bcm2835_codec_fmt	*fmt;
> +
> +	/* One extra buffer header so we can send an EOS. */
> +	struct m2m_mmal_buffer	eos_buffer;
> +	bool			eos_buffer_in_use;	/* debug only */
> +};
> +
> +struct bcm2835_codec_dev {
> +	struct vchiq_device *device;
> +
> +	/* v4l2 devices */
> +	struct v4l2_device	v4l2_dev;
> +	struct video_device	vfd;
> +	/* mutex for the v4l2 device */
> +	struct mutex		dev_mutex;
> +	atomic_t		num_inst;
> +
> +	/* allocated mmal instance and components */
> +	enum bcm2835_codec_role	role;
> +	/* The list of formats supported on input and output queues. */
> +	struct bcm2835_codec_fmt_list	supported_fmts[2];
> +
> +	/*
> +	 * Max size supported varies based on role. Store during
> +	 * bcm2835_codec_create for use later.
> +	 */
> +	unsigned int max_w;
> +	unsigned int max_h;
> +
> +	struct vchiq_mmal_instance	*instance;
> +
> +	struct v4l2_m2m_dev	*m2m_dev;
> +};
> +
> +struct bcm2835_codec_ctx {
> +	struct v4l2_fh		fh;
> +	struct bcm2835_codec_dev	*dev;
> +
> +	struct v4l2_ctrl_handler hdl;
> +	struct v4l2_ctrl *gop_size;
> +
> +	struct vchiq_mmal_component  *component;
> +	bool component_enabled;
> +
> +	enum v4l2_colorspace	colorspace;
> +	enum v4l2_ycbcr_encoding ycbcr_enc;
> +	enum v4l2_xfer_func	xfer_func;
> +	enum v4l2_quantization	quant;
> +
> +	int hflip;
> +	int vflip;
> +
> +	/* Source and destination queue data */
> +	struct bcm2835_codec_q_data   q_data[2];
> +	s32  bitrate;
> +	unsigned int	framerate_num;
> +	unsigned int	framerate_denom;
> +
> +	bool aborting;
> +	int num_ip_buffers;
> +	int num_op_buffers;
> +	struct completion frame_cmplt;
> +};
> +
> +struct bcm2835_codec_driver {
> +	struct vchiq_device	*device;
> +	struct media_device	mdev;
> +
> +	struct bcm2835_codec_dev *encode;
> +	struct bcm2835_codec_dev *decode;
> +	struct bcm2835_codec_dev *isp;
> +	struct bcm2835_codec_dev *deinterlace;
> +	struct bcm2835_codec_dev *encode_image;
> +};
> +
> +enum {
> +	V4L2_M2M_SRC = 0,
> +	V4L2_M2M_DST = 1,
> +};
> +
> +static const struct bcm2835_codec_fmt *get_fmt(u32 mmal_fmt)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(supported_formats); i++) {
> +		if (supported_formats[i].mmal_fmt == mmal_fmt &&
> +		    (!disable_bayer || !supported_formats[i].is_bayer))
> +			return &supported_formats[i];
> +	}
> +	return NULL;
> +}
> +
> +static inline
> +struct bcm2835_codec_fmt_list *get_format_list(struct bcm2835_codec_dev *dev,
> +					       bool capture)
> +{
> +	return &dev->supported_fmts[capture ? 1 : 0];
> +}
> +
> +static
> +struct bcm2835_codec_fmt *get_default_format(struct bcm2835_codec_dev *dev,
> +					     bool capture)
> +{
> +	return &dev->supported_fmts[capture ? 1 : 0].list[0];
> +}
> +
> +static
> +struct bcm2835_codec_fmt *find_format_pix_fmt(u32 pix_fmt,
> +					      struct bcm2835_codec_dev *dev,
> +					      bool capture)
> +{
> +	struct bcm2835_codec_fmt *fmt;
> +	unsigned int k;
> +	struct bcm2835_codec_fmt_list *fmts =
> +					&dev->supported_fmts[capture ? 1 : 0];
> +
> +	for (k = 0; k < fmts->num_entries; k++) {
> +		fmt = &fmts->list[k];
> +		if (fmt->fourcc == pix_fmt)
> +			break;
> +	}
> +	if (k == fmts->num_entries)
> +		return NULL;
> +
> +	return &fmts->list[k];
> +}
> +
> +static inline
> +struct bcm2835_codec_fmt *find_format(struct v4l2_format *f,
> +				      struct bcm2835_codec_dev *dev,
> +				      bool capture)
> +{
> +	return find_format_pix_fmt(f->fmt.pix_mp.pixelformat, dev, capture);
> +}
> +
> +static inline struct bcm2835_codec_ctx *file2ctx(struct file *file)
> +{
> +	return container_of(file->private_data, struct bcm2835_codec_ctx, fh);
> +}
> +
> +static struct bcm2835_codec_q_data *get_q_data(struct bcm2835_codec_ctx *ctx,
> +					       enum v4l2_buf_type type)
> +{
> +	switch (type) {
> +	case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
> +		return &ctx->q_data[V4L2_M2M_SRC];
> +	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
> +		return &ctx->q_data[V4L2_M2M_DST];
> +	default:
> +		v4l2_err(&ctx->dev->v4l2_dev, "%s: Invalid queue type %u\n",
> +			 __func__, type);
> +		break;
> +	}
> +	return NULL;
> +}
> +
> +static struct vchiq_mmal_port *get_port_data(struct bcm2835_codec_ctx *ctx,
> +					     enum v4l2_buf_type type)
> +{
> +	if (!ctx->component)
> +		return NULL;
> +
> +	switch (type) {
> +	case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
> +		return &ctx->component->input[0];
> +	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
> +		return &ctx->component->output[0];
> +	default:
> +		v4l2_err(&ctx->dev->v4l2_dev, "%s: Invalid queue type %u\n",
> +			 __func__, type);
> +		break;
> +	}
> +	return NULL;
> +}
> +
> +/*
> + * mem2mem callbacks
> + */
> +
> +/*
> + * job_ready() - check whether an instance is ready to be scheduled to run
> + */
> +static int job_ready(void *priv)
> +{
> +	struct bcm2835_codec_ctx *ctx = priv;
> +
> +	if (!v4l2_m2m_num_src_bufs_ready(ctx->fh.m2m_ctx) &&
> +	    !v4l2_m2m_num_dst_bufs_ready(ctx->fh.m2m_ctx))
> +		return 0;
> +
> +	return 1;
> +}
> +
> +static void job_abort(void *priv)
> +{
> +	struct bcm2835_codec_ctx *ctx = priv;
> +
> +	v4l2_dbg(1, debug, &ctx->dev->v4l2_dev, "%s\n", __func__);
> +	/* Will cancel the transaction in the next interrupt handler */
> +	ctx->aborting = 1;
> +}
> +
> +static inline unsigned int get_sizeimage(int bpl, int width, int height,
> +					 struct bcm2835_codec_fmt *fmt)
> +{
> +	if (fmt->flags & V4L2_FMT_FLAG_COMPRESSED) {
> +		if (fmt->fourcc == V4L2_PIX_FMT_JPEG)
> +			return DEF_COMP_BUF_SIZE_JPEG;
> +
> +		if (width * height > 1280 * 720)
> +			return DEF_COMP_BUF_SIZE_GREATER_720P;
> +		else
> +			return DEF_COMP_BUF_SIZE_720P_OR_LESS;
> +	}
> +
> +	if (fmt->fourcc != V4L2_PIX_FMT_NV12_COL128)
> +		return (bpl * height * fmt->size_multiplier_x2) >> 1;
> +
> +	/*
> +	 * V4L2_PIX_FMT_NV12_COL128 is 128 pixel wide columns.
> +	 * bytesperline is the column stride in lines, so multiply by
> +	 * the number of columns and 128.
> +	 */
> +	return (ALIGN(width, 128) * bpl);

I'd like to see these into v4l2-common, though you seem to have made a good
effort to avoid duplicating it.

> +}
> +
> +static inline unsigned int get_bytesperline(int width, int height,
> +					    struct bcm2835_codec_fmt *fmt,
> +					    enum bcm2835_codec_role role)
> +{
> +	if (fmt->fourcc != V4L2_PIX_FMT_NV12_COL128)
> +		return ALIGN((width * fmt->depth) >> 3,
> +			     fmt->bytesperline_align[role]);
> +
> +	/*
> +	 * V4L2_PIX_FMT_NV12_COL128 passes the column stride in lines via
> +	 * bytesperline.
> +	 * The minimum value for this is sufficient for the base luma and chroma
> +	 * with no padding.
> +	 */
> +	return (height * 3) >> 1;

I'm not sure for multiplanar format, but I'll assume this is single allocaiton
since you named it NV12 rather then NV12M. In single allocation formats, it is
requires that the plane size matches:

  bytesperline * height

It seems like you are not respecting this rules, I will try and comment against
the original format definition. If its a multi-allocation format, maybe we can
skip that rule, but I'm not very keen too personally. I'll have to review the
associated format definition to comment further, but I sense there is a conflict
with best practices.

> +}
> +
> +static void setup_mmal_port_format(struct bcm2835_codec_ctx *ctx,
> +				   struct bcm2835_codec_q_data *q_data,
> +				   struct vchiq_mmal_port *port)
> +{
> +	port->format.encoding = q_data->fmt->mmal_fmt;
> +	port->format.flags = 0;
> +
> +	if (!(q_data->fmt->flags & V4L2_FMT_FLAG_COMPRESSED)) {
> +		if (q_data->fmt->mmal_fmt != MMAL_ENCODING_YUVUV128) {
> +			/* Raw image format - set width/height */
> +			port->es.video.width = (q_data->bytesperline << 3) /
> +							q_data->fmt->depth;
> +			port->es.video.height = q_data->height;
> +			port->es.video.crop.width = q_data->crop_width;
> +			port->es.video.crop.height = q_data->crop_height;
> +		} else {
> +			/* NV12_COL128 / YUVUV128 column format */
> +			/* Column stride in lines */
> +			port->es.video.width = q_data->bytesperline;
> +			port->es.video.height = q_data->height;
> +			port->es.video.crop.width = q_data->crop_width;
> +			port->es.video.crop.height = q_data->crop_height;
> +			port->format.flags = MMAL_ES_FORMAT_FLAG_COL_FMTS_WIDTH_IS_COL_STRIDE;
> +		}
> +		port->es.video.frame_rate.numerator = ctx->framerate_num;
> +		port->es.video.frame_rate.denominator = ctx->framerate_denom;
> +	} else {
> +		/* Compressed format - leave resolution as 0 for decode */
> +		if (ctx->dev->role == DECODE) {
> +			port->es.video.width = 0;
> +			port->es.video.height = 0;
> +			port->es.video.crop.width = 0;
> +			port->es.video.crop.height = 0;
> +		} else {
> +			port->es.video.width = q_data->crop_width;
> +			port->es.video.height = q_data->height;
> +			port->es.video.crop.width = q_data->crop_width;
> +			port->es.video.crop.height = q_data->crop_height;
> +			port->format.bitrate = ctx->bitrate;
> +			port->es.video.frame_rate.numerator = ctx->framerate_num;
> +			port->es.video.frame_rate.denominator = ctx->framerate_denom;
> +		}
> +	}
> +	port->es.video.crop.x = 0;
> +	port->es.video.crop.y = 0;
> +
> +	port->current_buffer.size = q_data->sizeimage;
> +};
> +
> +static void ip_buffer_cb(struct vchiq_mmal_instance *instance,
> +			 struct vchiq_mmal_port *port, int status,
> +			 struct mmal_buffer *mmal_buf)
> +{
> +	struct bcm2835_codec_ctx *ctx = port->cb_ctx/*, *curr_ctx*/;
> +	struct m2m_mmal_buffer *buf =
> +			container_of(mmal_buf, struct m2m_mmal_buffer, mmal);
> +
> +	v4l2_dbg(2, debug, &ctx->dev->v4l2_dev, "%s: port %p buf %p length %lu, flags %x\n",
> +		 __func__, port, mmal_buf, mmal_buf->length,
> +		 mmal_buf->mmal_flags);
> +
> +	if (buf == &ctx->q_data[V4L2_M2M_SRC].eos_buffer) {
> +		/* Do we need to add lcoking to prevent multiple submission of

Fake this a fixme perhaps ? also lcoking -> locking

> +		 * the EOS, and therefore handle mutliple return here?
> +		 */
> +		v4l2_dbg(1, debug, &ctx->dev->v4l2_dev, "%s: eos buffer returned.\n",
> +			 __func__);
> +		ctx->q_data[V4L2_M2M_SRC].eos_buffer_in_use = false;
> +		return;
> +	}
> +
> +	if (status) {
> +		/* error in transfer */
> +		if (buf)
> +			/* there was a buffer with the error so return it */
> +			vb2_buffer_done(&buf->m2m.vb.vb2_buf,
> +					VB2_BUF_STATE_ERROR);
> +		return;
> +	}
> +	if (mmal_buf->cmd) {
> +		v4l2_err(&ctx->dev->v4l2_dev, "%s: Not expecting cmd msgs on ip callback - %08x\n",
> +			 __func__, mmal_buf->cmd);
> +		/*
> +		 * CHECKME: Should we return here. The buffer shouldn't have a
> +		 * message context or vb2 buf associated.
> +		 */
> +	}
> +
> +	v4l2_dbg(3, debug, &ctx->dev->v4l2_dev, "%s: no error. Return buffer %p\n",
> +		 __func__, &buf->m2m.vb.vb2_buf);
> +	vb2_buffer_done(&buf->m2m.vb.vb2_buf,
> +			port->enabled ? VB2_BUF_STATE_DONE :
> +					VB2_BUF_STATE_QUEUED);
> +
> +	ctx->num_ip_buffers++;
> +	v4l2_dbg(2, debug, &ctx->dev->v4l2_dev, "%s: done %d input buffers\n",
> +		 __func__, ctx->num_ip_buffers);
> +
> +	if (!port->enabled && atomic_read(&port->buffers_with_vpu))
> +		complete(&ctx->frame_cmplt);
> +}
> +
> +static void queue_res_chg_event(struct bcm2835_codec_ctx *ctx)
> +{
> +	static const struct v4l2_event ev_src_ch = {
> +		.type = V4L2_EVENT_SOURCE_CHANGE,
> +		.u.src_change.changes =
> +		V4L2_EVENT_SRC_CH_RESOLUTION,
> +	};
> +
> +	v4l2_event_queue_fh(&ctx->fh, &ev_src_ch);
> +}
> +
> +static void send_eos_event(struct bcm2835_codec_ctx *ctx)
> +{
> +	static const struct v4l2_event ev = {
> +		.type = V4L2_EVENT_EOS,
> +	};
> +
> +	v4l2_dbg(1, debug, &ctx->dev->v4l2_dev, "Sending EOS event\n");
> +
> +	v4l2_event_queue_fh(&ctx->fh, &ev);
> +}
> +
> +static void color_mmal2v4l(struct bcm2835_codec_ctx *ctx, u32 encoding,
> +			   u32 color_space)
> +{
> +	int is_rgb;
> +
> +	switch (encoding) {
> +	case MMAL_ENCODING_I420:
> +	case MMAL_ENCODING_YV12:
> +	case MMAL_ENCODING_NV12:
> +	case MMAL_ENCODING_NV21:
> +	case V4L2_PIX_FMT_YUYV:
> +	case V4L2_PIX_FMT_YVYU:
> +	case V4L2_PIX_FMT_UYVY:
> +	case V4L2_PIX_FMT_VYUY:
> +		/* YUV based colourspaces */
> +		switch (color_space) {
> +		case MMAL_COLOR_SPACE_ITUR_BT601:
> +			ctx->colorspace = V4L2_COLORSPACE_SMPTE170M;
> +			break;
> +
> +		case MMAL_COLOR_SPACE_ITUR_BT709:
> +			ctx->colorspace = V4L2_COLORSPACE_REC709;
> +			break;
> +		default:
> +			break;
> +		}
> +		break;
> +	default:
> +		/* RGB based colourspaces */
> +		ctx->colorspace = V4L2_COLORSPACE_SRGB;
> +		break;
> +	}
> +	ctx->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(ctx->colorspace);
> +	ctx->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(ctx->colorspace);
> +	is_rgb = ctx->colorspace == V4L2_COLORSPACE_SRGB;
> +	ctx->quant = V4L2_MAP_QUANTIZATION_DEFAULT(is_rgb, ctx->colorspace,
> +						   ctx->ycbcr_enc);
> +}
> +
> +static void handle_fmt_changed(struct bcm2835_codec_ctx *ctx,
> +			       struct mmal_buffer *mmal_buf)
> +{
> +	struct bcm2835_codec_q_data *q_data;
> +	struct mmal_msg_event_format_changed *format =
> +		(struct mmal_msg_event_format_changed *)mmal_buf->buffer;
> +	struct mmal_parameter_video_interlace_type interlace;
> +	int interlace_size = sizeof(interlace);
> +	struct vb2_queue *vq;
> +	int ret;
> +
> +	v4l2_dbg(1, debug, &ctx->dev->v4l2_dev, "%s: Format changed: buff size min %u, rec %u, buff num min %u, rec %u\n",
> +		 __func__,
> +		 format->buffer_size_min,
> +		 format->buffer_size_recommended,
> +		 format->buffer_num_min,
> +		 format->buffer_num_recommended
> +		);
> +	if (format->format.type != MMAL_ES_TYPE_VIDEO) {
> +		v4l2_dbg(1, debug, &ctx->dev->v4l2_dev, "%s: Format changed but not video %u\n",
> +			 __func__, format->format.type);
> +		return;
> +	}
> +	v4l2_dbg(1, debug, &ctx->dev->v4l2_dev, "%s: Format changed to %ux%u, crop %ux%u, colourspace %08X\n",
> +		 __func__, format->es.video.width, format->es.video.height,
> +		 format->es.video.crop.width, format->es.video.crop.height,
> +		 format->es.video.color_space);
> +
> +	q_data = get_q_data(ctx, V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE);
> +	v4l2_dbg(1, debug, &ctx->dev->v4l2_dev, "%s: Format was %ux%u, crop %ux%u\n",
> +		 __func__, q_data->bytesperline, q_data->height,
> +		 q_data->crop_width, q_data->crop_height);
> +
> +	q_data->crop_width = format->es.video.crop.width;
> +	q_data->crop_height = format->es.video.crop.height;
> +	/*
> +	 * Stop S_FMT updating crop_height should it be unaligned.
> +	 * Client can still update the crop region via S_SELECTION should it
> +	 * really want to, but the decoder is likely to complain that the
> +	 * format then doesn't match.
> +	 */
> +	q_data->selection_set = true;
> +	q_data->bytesperline = get_bytesperline(format->es.video.width,
> +						format->es.video.height,
> +						q_data->fmt, ctx->dev->role);
> +
> +	q_data->height = format->es.video.height;
> +	q_data->sizeimage = format->buffer_size_min;
> +	if (format->es.video.color_space)
> +		color_mmal2v4l(ctx, format->format.encoding,
> +			       format->es.video.color_space);
> +
> +	q_data->aspect_ratio.numerator = format->es.video.par.numerator;
> +	q_data->aspect_ratio.denominator = format->es.video.par.denominator;
> +
> +	ret = vchiq_mmal_port_parameter_get(ctx->dev->instance,
> +					    &ctx->component->output[0],
> +					    MMAL_PARAMETER_VIDEO_INTERLACE_TYPE,
> +					    &interlace,
> +					    &interlace_size);
> +	if (!ret) {
> +		switch (interlace.mode) {
> +		case MMAL_INTERLACE_PROGRESSIVE:
> +		default:
> +			q_data->field = V4L2_FIELD_NONE;
> +			break;
> +		case MMAL_INTERLACE_FIELDS_INTERLEAVED_UPPER_FIRST:
> +			q_data->field = V4L2_FIELD_INTERLACED_TB;
> +			break;
> +		case MMAL_INTERLACE_FIELDS_INTERLEAVED_LOWER_FIRST:
> +			q_data->field = V4L2_FIELD_INTERLACED_BT;
> +			break;
> +		}
> +		v4l2_dbg(1, debug, &ctx->dev->v4l2_dev, "%s: interlace mode %u, v4l2 field %u\n",
> +			 __func__, interlace.mode, q_data->field);
> +	} else {
> +		q_data->field = V4L2_FIELD_NONE;
> +	}
> +
> +	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE);
> +	if (vq->streaming)
> +		vq->last_buffer_dequeued = true;
> +
> +	queue_res_chg_event(ctx);
> +}
> +
> +static void op_buffer_cb(struct vchiq_mmal_instance *instance,
> +			 struct vchiq_mmal_port *port, int status,
> +			 struct mmal_buffer *mmal_buf)
> +{
> +	struct bcm2835_codec_ctx *ctx = port->cb_ctx;
> +	enum vb2_buffer_state buf_state = VB2_BUF_STATE_DONE;
> +	struct m2m_mmal_buffer *buf;
> +	struct vb2_v4l2_buffer *vb2;
> +
> +	v4l2_dbg(2, debug, &ctx->dev->v4l2_dev,
> +		 "%s: status:%d, buf:%p, length:%lu, flags %04x, pts %lld\n",
> +		 __func__, status, mmal_buf, mmal_buf->length,
> +		 mmal_buf->mmal_flags, mmal_buf->pts);
> +
> +	buf = container_of(mmal_buf, struct m2m_mmal_buffer, mmal);
> +	vb2 = &buf->m2m.vb;
> +
> +	if (status) {
> +		/* error in transfer */
> +		if (vb2) {
> +			/* there was a buffer with the error so return it */
> +			vb2_buffer_done(&vb2->vb2_buf, VB2_BUF_STATE_ERROR);
> +		}
> +		return;
> +	}
> +
> +	if (mmal_buf->cmd) {
> +		switch (mmal_buf->cmd) {
> +		case MMAL_EVENT_FORMAT_CHANGED:
> +		{
> +			handle_fmt_changed(ctx, mmal_buf);
> +			break;
> +		}
> +		default:
> +			v4l2_err(&ctx->dev->v4l2_dev, "%s: Unexpected event on output callback - %08x\n",
> +				 __func__, mmal_buf->cmd);
> +			break;
> +		}
> +		return;
> +	}
> +
> +	v4l2_dbg(3, debug, &ctx->dev->v4l2_dev, "%s: length %lu, flags %x, idx %u\n",
> +		 __func__, mmal_buf->length, mmal_buf->mmal_flags,
> +		 vb2->vb2_buf.index);
> +
> +	if (mmal_buf->length == 0) {
> +		/* stream ended, or buffer being returned during disable. */
> +		v4l2_dbg(2, debug, &ctx->dev->v4l2_dev, "%s: Empty buffer - flags %04x",
> +			 __func__, mmal_buf->mmal_flags);
> +		if (!(mmal_buf->mmal_flags & MMAL_BUFFER_HEADER_FLAG_EOS)) {
> +			if (!port->enabled) {
> +				vb2_buffer_done(&vb2->vb2_buf, VB2_BUF_STATE_QUEUED);
> +				if (atomic_read(&port->buffers_with_vpu))
> +					complete(&ctx->frame_cmplt);
> +			} else {
> +				vchiq_mmal_submit_buffer(ctx->dev->instance,
> +							 &ctx->component->output[0],
> +							 mmal_buf);
> +			}
> +			return;
> +		}
> +	}
> +	if (mmal_buf->mmal_flags & MMAL_BUFFER_HEADER_FLAG_EOS) {
> +		/* EOS packet from the VPU */
> +		send_eos_event(ctx);
> +		vb2->flags |= V4L2_BUF_FLAG_LAST;
> +	}
> +
> +	if (mmal_buf->mmal_flags & MMAL_BUFFER_HEADER_FLAG_CORRUPTED)
> +		buf_state = VB2_BUF_STATE_ERROR;
> +
> +	/* vb2 timestamps in nsecs, mmal in usecs */
> +	vb2->vb2_buf.timestamp = mmal_buf->pts * 1000;

M2M drivers are not allowed to "interpret" the timesamp field. They can only
copy it over. This scaling of the timestamp seems problematic and may possibly
impair some userspace ability to match in and out buffers. Is there some other
user data that could be use to maintain the lower bits ?

I realized that it should not have worked for GStreamer, since it uses a frame
counter as timestamp (and no real timestamp), but accidentally, it only uses
tv_sec member (with a implicit cast from signed to unsigned, but lets not grab
other projects issues in, unlike stateless, there is a single representation of
it, so its less of an issue).

https://gitlab.freedesktop.org/gstreamer/gstreamer/-/blob/main/subprojects/gst-plugins-good/sys/v4l2/gstv4l2bufferpool.c?ref_type=heads#L1179

There is no requirement in the spec that tells userspace using forward counters
to only use the seconds, so I suppose this is far from ideal.

> +
> +	vb2_set_plane_payload(&vb2->vb2_buf, 0, mmal_buf->length);
> +	switch (mmal_buf->mmal_flags &
> +				(MMAL_BUFFER_HEADER_VIDEO_FLAG_INTERLACED |
> +				 MMAL_BUFFER_HEADER_VIDEO_FLAG_TOP_FIELD_FIRST)) {
> +	case 0:
> +	case MMAL_BUFFER_HEADER_VIDEO_FLAG_TOP_FIELD_FIRST: /* Bogus */
> +		vb2->field = V4L2_FIELD_NONE;
> +		break;
> +	case MMAL_BUFFER_HEADER_VIDEO_FLAG_INTERLACED:
> +		vb2->field = V4L2_FIELD_INTERLACED_BT;
> +		break;
> +	case (MMAL_BUFFER_HEADER_VIDEO_FLAG_INTERLACED |
> +	      MMAL_BUFFER_HEADER_VIDEO_FLAG_TOP_FIELD_FIRST):
> +		vb2->field = V4L2_FIELD_INTERLACED_TB;
> +		break;
> +	}
> +
> +	if (mmal_buf->mmal_flags & MMAL_BUFFER_HEADER_FLAG_KEYFRAME)
> +		vb2->flags |= V4L2_BUF_FLAG_KEYFRAME;
> +
> +	vb2_buffer_done(&vb2->vb2_buf, buf_state);
> +	ctx->num_op_buffers++;
> +
> +	v4l2_dbg(2, debug, &ctx->dev->v4l2_dev, "%s: done %d output buffers\n",
> +		 __func__, ctx->num_op_buffers);
> +
> +	if (!port->enabled && atomic_read(&port->buffers_with_vpu))
> +		complete(&ctx->frame_cmplt);
> +}
> +
> +/* vb2_to_mmal_buffer() - converts vb2 buffer header to MMAL
> + *
> + * Copies all the required fields from a VB2 buffer to the MMAL buffer header,
> + * ready for sending to the VPU.
> + */
> +static void vb2_to_mmal_buffer(struct m2m_mmal_buffer *buf,
> +			       struct vb2_v4l2_buffer *vb2)
> +{
> +	u64 pts;
> +
> +	buf->mmal.mmal_flags = 0;
> +	if (vb2->flags & V4L2_BUF_FLAG_KEYFRAME)
> +		buf->mmal.mmal_flags |= MMAL_BUFFER_HEADER_FLAG_KEYFRAME;
> +
> +	/*
> +	 * Adding this means that the data must be framed correctly as one frame
> +	 * per buffer. The underlying decoder has no such requirement, but it
> +	 * will reduce latency as the bistream parser will be kicked immediately
> +	 * to parse the frame, rather than relying on its own heuristics for
> +	 * when to wake up.
> +	 */
> +	buf->mmal.mmal_flags |= MMAL_BUFFER_HEADER_FLAG_FRAME_END;

We do the same in wave5, in fact, we could not reliably implement m2m jobs and
power management. Though, as you have no ring buffer, are you able to replay
multiple buffer when an incomplete frame is detected ? Or does it means you
don't support multiple qbuf per frames ? Not a defect though, the spec makes
this encouraged by optional really.

> +
> +	buf->mmal.length = vb2->vb2_buf.planes[0].bytesused;
> +	/*
> +	 * Minor ambiguity in the V4L2 spec as to whether passing in a 0 length
> +	 * buffer, or one with V4L2_BUF_FLAG_LAST set denotes end of stream.
> +	 * Handle either.
> +	 */

Zero length EOS method is deprecated and the framework prevents it by default.
If you strictly need to support such userspace, your driver should set
q->allow_zero_bytesused. Note that this is normally not expected in newly
written driver.

> +	if (!buf->mmal.length || vb2->flags & V4L2_BUF_FLAG_LAST)
> +		buf->mmal.mmal_flags |= MMAL_BUFFER_HEADER_FLAG_EOS;
> +
> +	/* vb2 timestamps in nsecs, mmal in usecs */
> +	pts = vb2->vb2_buf.timestamp;
> +	do_div(pts, 1000);
> +	buf->mmal.pts = pts;
> +	buf->mmal.dts = MMAL_TIME_UNKNOWN;

PTS division here, lost of data.

> +
> +	switch (field_override ? field_override : vb2->field) {
> +	default:
> +	case V4L2_FIELD_NONE:
> +		break;
> +	case V4L2_FIELD_INTERLACED_BT:
> +		buf->mmal.mmal_flags |= MMAL_BUFFER_HEADER_VIDEO_FLAG_INTERLACED;
> +		break;
> +	case V4L2_FIELD_INTERLACED_TB:
> +		buf->mmal.mmal_flags |= MMAL_BUFFER_HEADER_VIDEO_FLAG_INTERLACED |
> +					MMAL_BUFFER_HEADER_VIDEO_FLAG_TOP_FIELD_FIRST;
> +		break;
> +	}
> +}
> +
> +/* device_run() - prepares and starts the device
> + *
> + * This simulates all the immediate preparations required before starting
> + * a device. This will be called by the framework when it decides to schedule
> + * a particular instance.
> + */
> +static void device_run(void *priv)
> +{
> +	struct bcm2835_codec_ctx *ctx = priv;
> +	struct bcm2835_codec_dev *dev = ctx->dev;
> +	struct vb2_v4l2_buffer *src_buf, *dst_buf;
> +	struct m2m_mmal_buffer *src_m2m_buf = NULL, *dst_m2m_buf = NULL;
> +	struct v4l2_m2m_buffer *m2m;
> +	int ret;
> +
> +	v4l2_dbg(3, debug, &ctx->dev->v4l2_dev, "%s: off we go\n", __func__);
> +
> +	if (ctx->fh.m2m_ctx->out_q_ctx.q.streaming) {

The frameworks currently hardcode the requirement that the output queue is
streaming in order for device_run to be called. For this reason, this check is
always true.

> +		src_buf = v4l2_m2m_buf_remove(&ctx->fh.m2m_ctx->out_q_ctx);
> +		if (src_buf) {
> +			m2m = container_of(src_buf, struct v4l2_m2m_buffer, vb);
> +			src_m2m_buf = container_of(m2m, struct m2m_mmal_buffer,
> +						   m2m);
> +			vb2_to_mmal_buffer(src_m2m_buf, src_buf);
> +
> +			ret = vchiq_mmal_submit_buffer(dev->instance,
> +						       &ctx->component->input[0],
> +						       &src_m2m_buf->mmal);
> +			v4l2_dbg(3, debug, &ctx->dev->v4l2_dev,
> +				 "%s: Submitted ip buffer len %lu, pts %llu, flags %04x\n",
> +				 __func__, src_m2m_buf->mmal.length,
> +				 src_m2m_buf->mmal.pts,
> +				 src_m2m_buf->mmal.mmal_flags);
> +			if (ret)
> +				v4l2_err(&ctx->dev->v4l2_dev,
> +					 "%s: Failed submitting ip buffer\n",
> +					 __func__);
> +		}
> +	}
> +
> +	if (ctx->fh.m2m_ctx->cap_q_ctx.q.streaming) {
> +		dst_buf = v4l2_m2m_buf_remove(&ctx->fh.m2m_ctx->cap_q_ctx);
> +		if (dst_buf) {
> +			m2m = container_of(dst_buf, struct v4l2_m2m_buffer, vb);
> +			dst_m2m_buf = container_of(m2m, struct m2m_mmal_buffer,
> +						   m2m);
> +			vb2_to_mmal_buffer(dst_m2m_buf, dst_buf);
> +
> +			v4l2_dbg(3, debug, &ctx->dev->v4l2_dev,
> +				 "%s: Submitted op buffer\n", __func__);
> +			ret = vchiq_mmal_submit_buffer(dev->instance,
> +						       &ctx->component->output[0],
> +						       &dst_m2m_buf->mmal);
> +			if (ret)
> +				v4l2_err(&ctx->dev->v4l2_dev,
> +					 "%s: Failed submitting op buffer\n",
> +					 __func__);
> +		}
> +	}
> +
> +	v4l2_dbg(3, debug, &ctx->dev->v4l2_dev, "%s: Submitted src %p, dst %p\n",
> +		 __func__, src_m2m_buf, dst_m2m_buf);
> +
> +	/* Complete the job here. */
> +	v4l2_m2m_job_finish(ctx->dev->m2m_dev, ctx->fh.m2m_ctx);
> +}
> +
> +/*
> + * video ioctls
> + */
> +static int vidioc_querycap(struct file *file, void *priv,
> +			   struct v4l2_capability *cap)
> +{
> +	struct bcm2835_codec_dev *dev = video_drvdata(file);
> +
> +	strncpy(cap->driver, MEM2MEM_NAME, sizeof(cap->driver) - 1);
> +	strncpy(cap->card, dev->vfd.name, sizeof(cap->card) - 1);
> +	snprintf(cap->bus_info, sizeof(cap->bus_info), "platform:%s",
> +		 MEM2MEM_NAME);

You can drop this line, it will be filled for you.

> +	return 0;
> +}
> +
> +static int enum_fmt(struct v4l2_fmtdesc *f, struct bcm2835_codec_ctx *ctx,
> +		    bool capture)
> +{
> +	struct bcm2835_codec_fmt *fmt;
> +	struct bcm2835_codec_fmt_list *fmts =
> +					get_format_list(ctx->dev, capture);
> +
> +	if (f->index < fmts->num_entries) {
> +		/* Format found */
> +		fmt = &fmts->list[f->index];
> +		f->pixelformat = fmt->fourcc;
> +		f->flags = fmt->flags;
> +		return 0;
> +	}
> +
> +	/* Format not found */
> +	return -EINVAL;
> +}
> +
> +static int vidioc_enum_fmt_vid_cap(struct file *file, void *priv,
> +				   struct v4l2_fmtdesc *f)
> +{
> +	struct bcm2835_codec_ctx *ctx = file2ctx(file);
> +
> +	return enum_fmt(f, ctx, true);
> +}
> +
> +static int vidioc_enum_fmt_vid_out(struct file *file, void *priv,
> +				   struct v4l2_fmtdesc *f)
> +{
> +	struct bcm2835_codec_ctx *ctx = file2ctx(file);
> +
> +	return enum_fmt(f, ctx, false);
> +}
> +
> +static int vidioc_g_fmt(struct bcm2835_codec_ctx *ctx, struct v4l2_format *f)
> +{
> +	struct vb2_queue *vq;
> +	struct bcm2835_codec_q_data *q_data;
> +
> +	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
> +	if (!vq)
> +		return -EINVAL;
> +
> +	q_data = get_q_data(ctx, f->type);
> +
> +	f->fmt.pix_mp.width			= q_data->crop_width;
> +	f->fmt.pix_mp.height			= q_data->height;
> +	f->fmt.pix_mp.pixelformat		= q_data->fmt->fourcc;
> +	f->fmt.pix_mp.field			= q_data->field;
> +	f->fmt.pix_mp.colorspace		= ctx->colorspace;
> +	f->fmt.pix_mp.plane_fmt[0].sizeimage	= q_data->sizeimage;
> +	f->fmt.pix_mp.plane_fmt[0].bytesperline	= q_data->bytesperline;
> +	f->fmt.pix_mp.num_planes		= 1;
> +	f->fmt.pix_mp.ycbcr_enc			= ctx->ycbcr_enc;
> +	f->fmt.pix_mp.quantization		= ctx->quant;
> +	f->fmt.pix_mp.xfer_func			= ctx->xfer_func;
> +
> +	memset(f->fmt.pix_mp.plane_fmt[0].reserved, 0,
> +	       sizeof(f->fmt.pix_mp.plane_fmt[0].reserved));
> +
> +	return 0;
> +}
> +
> +static int vidioc_g_fmt_vid_out(struct file *file, void *priv,
> +				struct v4l2_format *f)
> +{
> +	return vidioc_g_fmt(file2ctx(file), f);
> +}
> +
> +static int vidioc_g_fmt_vid_cap(struct file *file, void *priv,
> +				struct v4l2_format *f)
> +{
> +	return vidioc_g_fmt(file2ctx(file), f);
> +}

My first impression is that these two wrappers are not useful, you can just fix
vidioc_g_fmt signature and use this twice in the op.

> +
> +static int vidioc_try_fmt(struct bcm2835_codec_ctx *ctx, struct v4l2_format *f,
> +			  struct bcm2835_codec_fmt *fmt)
> +{
> +	unsigned int sizeimage, min_bytesperline;
> +
> +	/*
> +	 * The V4L2 specification requires the driver to correct the format
> +	 * struct if any of the dimensions is unsupported
> +	 */
> +	if (f->fmt.pix_mp.width > ctx->dev->max_w)
> +		f->fmt.pix_mp.width = ctx->dev->max_w;
> +	if (f->fmt.pix_mp.height > ctx->dev->max_h)
> +		f->fmt.pix_mp.height = ctx->dev->max_h;
> +
> +	if (!(fmt->flags & V4L2_FMT_FLAG_COMPRESSED)) {
> +		/* Only clip min w/h on capture. Treat 0x0 as unknown. */
> +		if (f->fmt.pix_mp.width < MIN_W)
> +			f->fmt.pix_mp.width = MIN_W;
> +		if (f->fmt.pix_mp.height < MIN_H)
> +			f->fmt.pix_mp.height = MIN_H;
> +
> +		/*
> +		 * For decoders and image encoders the buffer must have
> +		 * a vertical alignment of 16 lines.
> +		 * The selection will reflect any cropping rectangle when only
> +		 * some of the pixels are active.
> +		 */
> +		if (ctx->dev->role == DECODE || ctx->dev->role == ENCODE_IMAGE)
> +			f->fmt.pix_mp.height = ALIGN(f->fmt.pix_mp.height, 16);
> +	}
> +	f->fmt.pix_mp.num_planes = 1;
> +	min_bytesperline = get_bytesperline(f->fmt.pix_mp.width,
> +					    f->fmt.pix_mp.height,
> +					    fmt, ctx->dev->role);
> +	if (f->fmt.pix_mp.plane_fmt[0].bytesperline < min_bytesperline)
> +		f->fmt.pix_mp.plane_fmt[0].bytesperline = min_bytesperline;
> +	f->fmt.pix_mp.plane_fmt[0].bytesperline =
> +		ALIGN(f->fmt.pix_mp.plane_fmt[0].bytesperline,
> +		      fmt->bytesperline_align[ctx->dev->role]);
> +
> +	sizeimage = get_sizeimage(f->fmt.pix_mp.plane_fmt[0].bytesperline,
> +				  f->fmt.pix_mp.width, f->fmt.pix_mp.height,
> +				  fmt);
> +	/*
> +	 * Drivers must set sizeimage for uncompressed formats
> +	 * Compressed formats allow the client to request an alternate
> +	 * size for the buffer.
> +	 */
> +	if (!(fmt->flags & V4L2_FMT_FLAG_COMPRESSED) ||
> +	    f->fmt.pix_mp.plane_fmt[0].sizeimage < sizeimage)
> +		f->fmt.pix_mp.plane_fmt[0].sizeimage = sizeimage;

nit: You can offer this to all formats really, no need to make it special. This
can be handy if you want to accommodate another driver requirement. It also
makes the code simpler.

> +
> +	memset(f->fmt.pix_mp.plane_fmt[0].reserved, 0,
> +	       sizeof(f->fmt.pix_mp.plane_fmt[0].reserved));

You can drop this, the ioctl layer already clears it with:

                memset_after(p, 0, fmt.pix_mp.xfer_func);
                for (i = 0; i < p->fmt.pix_mp.num_planes; i++)
                        memset_after(&p->fmt.pix_mp.plane_fmt[i],
                                     0, bytesperline);

> +
> +	if (ctx->dev->role == DECODE || ctx->dev->role == DEINTERLACE) {
> +		switch (f->fmt.pix_mp.field) {
> +		/*
> +		 * All of this is pretty much guesswork as we'll set the
> +		 * interlace format correctly come format changed, and signal
> +		 * it appropriately on each buffer.
> +		 */
> +		default:
> +		case V4L2_FIELD_NONE:
> +		case V4L2_FIELD_ANY:
> +			f->fmt.pix_mp.field = V4L2_FIELD_NONE;
> +			break;
> +		case V4L2_FIELD_INTERLACED:
> +			f->fmt.pix_mp.field = V4L2_FIELD_INTERLACED;
> +			break;
> +		case V4L2_FIELD_TOP:
> +		case V4L2_FIELD_BOTTOM:
> +		case V4L2_FIELD_INTERLACED_TB:
> +			f->fmt.pix_mp.field = V4L2_FIELD_INTERLACED_TB;
> +			break;
> +		case V4L2_FIELD_INTERLACED_BT:
> +			f->fmt.pix_mp.field = V4L2_FIELD_INTERLACED_BT;
> +			break;
> +		}
> +	} else {
> +		f->fmt.pix_mp.field = V4L2_FIELD_NONE;
> +	}
> +
> +	return 0;
> +}
> +
> +static int vidioc_try_fmt_vid_cap(struct file *file, void *priv,
> +				  struct v4l2_format *f)
> +{
> +	struct bcm2835_codec_fmt *fmt;
> +	struct bcm2835_codec_ctx *ctx = file2ctx(file);
> +
> +	fmt = find_format(f, ctx->dev, true);
> +	if (!fmt) {
> +		f->fmt.pix_mp.pixelformat = get_default_format(ctx->dev,
> +							       true)->fourcc;
> +		fmt = find_format(f, ctx->dev, true);
> +	}
> +
> +	return vidioc_try_fmt(ctx, f, fmt);
> +}
> +
> +static int vidioc_try_fmt_vid_out(struct file *file, void *priv,
> +				  struct v4l2_format *f)
> +{
> +	struct bcm2835_codec_fmt *fmt;
> +	struct bcm2835_codec_ctx *ctx = file2ctx(file);
> +
> +	fmt = find_format(f, ctx->dev, false);
> +	if (!fmt) {
> +		f->fmt.pix_mp.pixelformat = get_default_format(ctx->dev,
> +							       false)->fourcc;
> +		fmt = find_format(f, ctx->dev, false);
> +	}
> +
> +	if (!f->fmt.pix_mp.colorspace)
> +		f->fmt.pix_mp.colorspace = ctx->colorspace;
> +
> +	return vidioc_try_fmt(ctx, f, fmt);
> +}
> +
> +static int vidioc_s_fmt(struct bcm2835_codec_ctx *ctx, struct v4l2_format *f,
> +			unsigned int requested_height)
> +{
> +	struct bcm2835_codec_q_data *q_data;
> +	struct vb2_queue *vq;
> +	struct vchiq_mmal_port *port;
> +	bool update_capture_port = false;
> +	bool reenable_port = false;
> +	int ret;
> +
> +	v4l2_dbg(1, debug, &ctx->dev->v4l2_dev,	"Setting format for type %d, wxh: %dx%d, fmt: %08x, size %u\n",
> +		 f->type, f->fmt.pix_mp.width, f->fmt.pix_mp.height,
> +		 f->fmt.pix_mp.pixelformat,
> +		 f->fmt.pix_mp.plane_fmt[0].sizeimage);
> +
> +	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
> +	if (!vq)
> +		return -EINVAL;
> +
> +	q_data = get_q_data(ctx, f->type);
> +	if (!q_data)
> +		return -EINVAL;
> +
> +	if (vb2_is_busy(vq)) {
> +		v4l2_err(&ctx->dev->v4l2_dev, "%s queue busy\n", __func__);
> +		return -EBUSY;
> +	}
> +
> +	q_data->fmt = find_format(f, ctx->dev,
> +				  f->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE);
> +	q_data->crop_width = f->fmt.pix_mp.width;
> +	q_data->height = f->fmt.pix_mp.height;
> +	if (!q_data->selection_set ||
> +	    (q_data->fmt->flags & V4L2_FMT_FLAG_COMPRESSED))
> +		q_data->crop_height = requested_height;
> +
> +	/*
> +	 * Copying the behaviour of vicodec which retains a single set of
> +	 * colorspace parameters for both input and output.
> +	 */
> +	ctx->colorspace = f->fmt.pix_mp.colorspace;
> +	ctx->xfer_func = f->fmt.pix_mp.xfer_func;
> +	ctx->ycbcr_enc = f->fmt.pix_mp.ycbcr_enc;
> +	ctx->quant = f->fmt.pix_mp.quantization;
> +
> +	q_data->field = f->fmt.pix_mp.field;
> +
> +	/* All parameters should have been set correctly by try_fmt */
> +	q_data->bytesperline = f->fmt.pix_mp.plane_fmt[0].bytesperline;
> +	q_data->sizeimage = f->fmt.pix_mp.plane_fmt[0].sizeimage;
> +
> +	v4l2_dbg(1, debug, &ctx->dev->v4l2_dev,	"Calculated bpl as %u, size %u\n",
> +		 q_data->bytesperline, q_data->sizeimage);
> +
> +	if ((ctx->dev->role == DECODE || ctx->dev->role == ENCODE_IMAGE) &&
> +	    q_data->fmt->flags & V4L2_FMT_FLAG_COMPRESSED &&
> +	    q_data->crop_width && q_data->height) {
> +		/*
> +		 * On the decoder or image encoder, if provided with
> +		 * a resolution on the input side, then replicate that
> +		 * to the output side.
> +		 * GStreamer appears not to support V4L2_EVENT_SOURCE_CHANGE,
> +		 * nor set up a resolution on the output side, therefore
> +		 * we can't decode anything at a resolution other than the
> +		 * default one.
> +		 */

GStreamer fully supports this now. As I explain earlier, it actually let the
driver report the resolution before allocating the capture buffers now. For
backward compatibility with older GStreamer (and FFMPEG btw), which both had
implementation before SRC_CH spec even existed, you will want to guess the
capture format from the userspace provided display (or coded) resolution on the
output queue. In fact, as you have 32 or 64 pixel alignment, it will work in a
very wide variety of cases. Please reword the rationale for this (optional)
code.

> +		struct bcm2835_codec_q_data *q_data_dst =
> +						&ctx->q_data[V4L2_M2M_DST];
> +
> +		q_data_dst->crop_width = q_data->crop_width;
> +		q_data_dst->crop_height = q_data->crop_height;
> +		q_data_dst->height = ALIGN(q_data->crop_height, 16);
> +
> +		q_data_dst->bytesperline =
> +			get_bytesperline(f->fmt.pix_mp.width,
> +					 f->fmt.pix_mp.height,
> +					 q_data_dst->fmt, ctx->dev->role);
> +		q_data_dst->sizeimage = get_sizeimage(q_data_dst->bytesperline,
> +						      q_data_dst->crop_width,
> +						      q_data_dst->height,
> +						      q_data_dst->fmt);
> +		update_capture_port = true;
> +	}
> +
> +	/* If we have a component then setup the port as well */
> +	port = get_port_data(ctx, vq->type);
> +	if (!port)
> +		return 0;
> +
> +	if (port->enabled) {
> +		unsigned int num_buffers;
> +
> +		/*
> +		 * This should only ever happen with DECODE and the MMAL output
> +		 * port that has been enabled for resolution changed events.
> +		 * In this case no buffers have been allocated or sent to the
> +		 * component, so warn on that.
> +		 */
> +		WARN_ON(ctx->dev->role != DECODE ||
> +			f->type != V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE ||
> +			atomic_read(&port->buffers_with_vpu));
> +
> +		/*
> +		 * Disable will reread the port format, so retain buffer count.
> +		 */
> +		num_buffers = port->current_buffer.num;
> +
> +		ret = vchiq_mmal_port_disable(ctx->dev->instance, port);
> +		if (ret)
> +			v4l2_err(&ctx->dev->v4l2_dev, "%s: Error disabling port update buffer count, ret %d\n",
> +				 __func__, ret);
> +
> +		port->current_buffer.num = num_buffers;
> +
> +		reenable_port = true;
> +	}
> +
> +	setup_mmal_port_format(ctx, q_data, port);
> +	ret = vchiq_mmal_port_set_format(ctx->dev->instance, port);
> +	if (ret) {
> +		v4l2_err(&ctx->dev->v4l2_dev, "%s: Failed vchiq_mmal_port_set_format on port, ret %d\n",
> +			 __func__, ret);
> +		ret = -EINVAL;
> +	}
> +
> +	if (q_data->sizeimage < port->minimum_buffer.size) {
> +		v4l2_err(&ctx->dev->v4l2_dev, "%s: Current buffer size of %u < min buf size %u - driver mismatch to MMAL\n",
> +			 __func__, q_data->sizeimage,
> +			 port->minimum_buffer.size);
> +	}
> +
> +	if (reenable_port) {
> +		ret = vchiq_mmal_port_enable(ctx->dev->instance,
> +					     port,
> +					     op_buffer_cb);
> +		if (ret)
> +			v4l2_err(&ctx->dev->v4l2_dev, "%s: Failed enabling o/p port, ret %d\n",
> +				 __func__, ret);
> +	}
> +	v4l2_dbg(1, debug, &ctx->dev->v4l2_dev,	"Set format for type %d, wxh: %dx%d, fmt: %08x, size %u\n",
> +		 f->type, q_data->crop_width, q_data->height,
> +		 q_data->fmt->fourcc, q_data->sizeimage);
> +
> +	if (update_capture_port) {
> +		struct vchiq_mmal_port *port_dst = &ctx->component->output[0];
> +		struct bcm2835_codec_q_data *q_data_dst =
> +						&ctx->q_data[V4L2_M2M_DST];
> +
> +		setup_mmal_port_format(ctx, q_data_dst, port_dst);
> +		ret = vchiq_mmal_port_set_format(ctx->dev->instance, port_dst);
> +		if (ret) {
> +			v4l2_err(&ctx->dev->v4l2_dev, "%s: Failed vchiq_mmal_port_set_format on output port, ret %d\n",
> +				 __func__, ret);
> +			ret = -EINVAL;
> +		}
> +	}
> +	return ret;
> +}

nit: The mix of encoder, decoder and 1:1 filters in the same function introduce
a bit  of complexity. It would help to have specialized implementation per role,
and make turn that into an op table in the driver context.

> +
> +static int vidioc_s_fmt_vid_cap(struct file *file, void *priv,
> +				struct v4l2_format *f)
> +{
> +	unsigned int height = f->fmt.pix_mp.height;
> +	int ret;
> +
> +	ret = vidioc_try_fmt_vid_cap(file, priv, f);
> +	if (ret)
> +		return ret;
> +
> +	return vidioc_s_fmt(file2ctx(file), f, height);
> +}
> +
> +static int vidioc_s_fmt_vid_out(struct file *file, void *priv,
> +				struct v4l2_format *f)
> +{
> +	unsigned int height = f->fmt.pix_mp.height;
> +	int ret;
> +
> +	ret = vidioc_try_fmt_vid_out(file, priv, f);
> +	if (ret)
> +		return ret;
> +
> +	ret = vidioc_s_fmt(file2ctx(file), f, height);
> +	return ret;
> +}
> +
> +static int vidioc_g_selection(struct file *file, void *priv,
> +			      struct v4l2_selection *s)
> +{
> +	struct bcm2835_codec_ctx *ctx = file2ctx(file);
> +	struct bcm2835_codec_q_data *q_data;
> +
> +	/*
> +	 * The selection API takes V4L2_BUF_TYPE_VIDEO_CAPTURE and
> +	 * V4L2_BUF_TYPE_VIDEO_OUTPUT, even if the device implements the MPLANE
> +	 * API. The V4L2 core will have converted the MPLANE variants to
> +	 * non-MPLANE.
> +	 * Open code this instead of using get_q_data in this case.
> +	 */
> +	switch (s->type) {
> +	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
> +		/* CAPTURE on encoder is not valid. */
> +		if (ctx->dev->role == ENCODE || ctx->dev->role == ENCODE_IMAGE)
> +			return -EINVAL;
> +		q_data = &ctx->q_data[V4L2_M2M_DST];
> +		break;
> +	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> +		/* OUTPUT on deoder is not valid. */
> +		if (ctx->dev->role == DECODE)
> +			return -EINVAL;
> +		q_data = &ctx->q_data[V4L2_M2M_SRC];
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	switch (ctx->dev->role) {
> +	case DECODE:
> +		switch (s->target) {
> +		case V4L2_SEL_TGT_COMPOSE_DEFAULT:
> +		case V4L2_SEL_TGT_COMPOSE:
> +			s->r.left = 0;
> +			s->r.top = 0;
> +			s->r.width = q_data->crop_width;
> +			s->r.height = q_data->crop_height;
> +			break;
> +		case V4L2_SEL_TGT_COMPOSE_BOUNDS:
> +			s->r.left = 0;
> +			s->r.top = 0;
> +			s->r.width = q_data->crop_width;
> +			s->r.height = q_data->crop_height;
> +			break;
> +		case V4L2_SEL_TGT_CROP_BOUNDS:
> +		case V4L2_SEL_TGT_CROP_DEFAULT:
> +			s->r.left = 0;
> +			s->r.top = 0;
> +			s->r.width = (q_data->bytesperline << 3) /
> +						q_data->fmt->depth;
> +			s->r.height = q_data->height;
> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +		break;
> +	case ENCODE:
> +	case ENCODE_IMAGE:
> +		switch (s->target) {
> +		case V4L2_SEL_TGT_CROP_DEFAULT:
> +		case V4L2_SEL_TGT_CROP_BOUNDS:
> +			s->r.top = 0;
> +			s->r.left = 0;
> +			s->r.width = q_data->bytesperline;
> +			s->r.height = q_data->height;
> +			break;
> +		case V4L2_SEL_TGT_CROP:
> +			s->r.top = 0;
> +			s->r.left = 0;
> +			s->r.width = q_data->crop_width;
> +			s->r.height = q_data->crop_height;
> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +		break;
> +	case ISP:
> +	case DEINTERLACE:
> +		if (s->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
> +			switch (s->target) {
> +			case V4L2_SEL_TGT_COMPOSE_DEFAULT:
> +			case V4L2_SEL_TGT_COMPOSE:
> +				s->r.left = 0;
> +				s->r.top = 0;
> +				s->r.width = q_data->crop_width;
> +				s->r.height = q_data->crop_height;
> +				break;
> +			case V4L2_SEL_TGT_COMPOSE_BOUNDS:
> +				s->r.left = 0;
> +				s->r.top = 0;
> +				s->r.width = q_data->crop_width;
> +				s->r.height = q_data->crop_height;
> +				break;
> +			default:
> +				return -EINVAL;
> +			}
> +		} else {
> +			/* must be V4L2_BUF_TYPE_VIDEO_OUTPUT */
> +			switch (s->target) {
> +			case V4L2_SEL_TGT_CROP_DEFAULT:
> +			case V4L2_SEL_TGT_CROP_BOUNDS:
> +				s->r.top = 0;
> +				s->r.left = 0;
> +				s->r.width = q_data->bytesperline;
> +				s->r.height = q_data->height;
> +				break;
> +			case V4L2_SEL_TGT_CROP:
> +				s->r.top = 0;
> +				s->r.left = 0;
> +				s->r.width = q_data->crop_width;
> +				s->r.height = q_data->crop_height;
> +				break;
> +			default:
> +				return -EINVAL;
> +			}
> +		}
> +		break;
> +	case NUM_ROLES:
> +		break;
> +	}
> +
> +	return 0;
> +}
> +
> +static int vidioc_s_selection(struct file *file, void *priv,
> +			      struct v4l2_selection *s)
> +{
> +	struct bcm2835_codec_ctx *ctx = file2ctx(file);
> +	struct bcm2835_codec_q_data *q_data = NULL;
> +	struct vchiq_mmal_port *port = NULL;
> +	int ret;
> +
> +	/*
> +	 * The selection API takes V4L2_BUF_TYPE_VIDEO_CAPTURE and
> +	 * V4L2_BUF_TYPE_VIDEO_OUTPUT, even if the device implements the MPLANE
> +	 * API. The V4L2 core will have converted the MPLANE variants to
> +	 * non-MPLANE.
> +	 *
> +	 * Open code this instead of using get_q_data in this case.
> +	 */
> +	switch (s->type) {
> +	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
> +		/* CAPTURE on encoder is not valid. */
> +		if (ctx->dev->role == ENCODE || ctx->dev->role == ENCODE_IMAGE)
> +			return -EINVAL;
> +		q_data = &ctx->q_data[V4L2_M2M_DST];
> +		if (ctx->component)
> +			port = &ctx->component->output[0];
> +		break;
> +	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
> +		/* OUTPUT on deoder is not valid. */
> +		if (ctx->dev->role == DECODE)
> +			return -EINVAL;
> +		q_data = &ctx->q_data[V4L2_M2M_SRC];
> +		if (ctx->component)
> +			port = &ctx->component->input[0];
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	v4l2_dbg(1, debug, &ctx->dev->v4l2_dev, "%s: ctx %p, type %d, q_data %p, target %d, rect x/y %d/%d, w/h %ux%u\n",
> +		 __func__, ctx, s->type, q_data, s->target, s->r.left, s->r.top,
> +		 s->r.width, s->r.height);
> +
> +	switch (ctx->dev->role) {
> +	case DECODE:
> +		switch (s->target) {
> +		case V4L2_SEL_TGT_COMPOSE:
> +			/* Accept cropped image */
> +			s->r.left = 0;
> +			s->r.top = 0;
> +			s->r.width = min(s->r.width, q_data->crop_width);
> +			s->r.height = min(s->r.height, q_data->height);
> +			q_data->crop_width = s->r.width;
> +			q_data->crop_height = s->r.height;
> +			q_data->selection_set = true;
> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +		break;
> +	case ENCODE:
> +	case ENCODE_IMAGE:
> +		switch (s->target) {
> +		case V4L2_SEL_TGT_CROP:
> +			/* Only support crop from (0,0) */
> +			s->r.top = 0;
> +			s->r.left = 0;
> +			s->r.width = min(s->r.width, q_data->crop_width);
> +			s->r.height = min(s->r.height, q_data->height);
> +			q_data->crop_width = s->r.width;
> +			q_data->crop_height = s->r.height;
> +			q_data->selection_set = true;
> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +		break;
> +	case ISP:
> +	case DEINTERLACE:
> +		if (s->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
> +			switch (s->target) {
> +			case V4L2_SEL_TGT_COMPOSE:
> +				/* Accept cropped image */
> +				s->r.left = 0;
> +				s->r.top = 0;
> +				s->r.width = min(s->r.width, q_data->crop_width);
> +				s->r.height = min(s->r.height, q_data->height);
> +				q_data->crop_width = s->r.width;
> +				q_data->crop_height = s->r.height;
> +				q_data->selection_set = true;
> +				break;
> +			default:
> +				return -EINVAL;
> +			}
> +			break;
> +		} else {
> +			/* must be V4L2_BUF_TYPE_VIDEO_OUTPUT */
> +			switch (s->target) {
> +			case V4L2_SEL_TGT_CROP:
> +				/* Only support crop from (0,0) */
> +				s->r.top = 0;
> +				s->r.left = 0;
> +				s->r.width = min(s->r.width, q_data->crop_width);
> +				s->r.height = min(s->r.height, q_data->height);
> +				q_data->crop_width = s->r.width;
> +				q_data->crop_height = s->r.height;
> +				q_data->selection_set = true;
> +				break;
> +			default:
> +				return -EINVAL;
> +			}
> +			break;
> +		}
> +	case NUM_ROLES:
> +		break;
> +	}
> +
> +	if (!port)
> +		return 0;
> +
> +	setup_mmal_port_format(ctx, q_data, port);
> +	ret = vchiq_mmal_port_set_format(ctx->dev->instance, port);
> +	if (ret) {
> +		v4l2_err(&ctx->dev->v4l2_dev, "%s: Failed vchiq_mmal_port_set_format on port, ret %d\n",
> +			 __func__, ret);
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int vidioc_s_parm(struct file *file, void *priv,
> +			 struct v4l2_streamparm *parm)
> +{
> +	struct bcm2835_codec_ctx *ctx = file2ctx(file);
> +
> +	if (parm->type != V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE)
> +		return -EINVAL;
> +
> +	if (!parm->parm.output.timeperframe.denominator ||
> +	    !parm->parm.output.timeperframe.numerator)
> +		return -EINVAL;
> +
> +	ctx->framerate_num =
> +			parm->parm.output.timeperframe.denominator;
> +	ctx->framerate_denom =
> +			parm->parm.output.timeperframe.numerator;
> +
> +	parm->parm.output.capability = V4L2_CAP_TIMEPERFRAME;
> +
> +	return 0;
> +}
> +
> +static int vidioc_g_parm(struct file *file, void *priv,
> +			 struct v4l2_streamparm *parm)
> +{
> +	struct bcm2835_codec_ctx *ctx = file2ctx(file);
> +
> +	if (parm->type != V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE)
> +		return -EINVAL;
> +
> +	parm->parm.output.capability = V4L2_CAP_TIMEPERFRAME;
> +	parm->parm.output.timeperframe.denominator =
> +			ctx->framerate_num;
> +	parm->parm.output.timeperframe.numerator =
> +			ctx->framerate_denom;
> +
> +	return 0;
> +}
> +
> +static int vidioc_g_pixelaspect(struct file *file, void *fh, int type,
> +				struct v4l2_fract *f)
> +{
> +	struct bcm2835_codec_ctx *ctx = file2ctx(file);
> +
> +	/*
> +	 * The selection API takes V4L2_BUF_TYPE_VIDEO_CAPTURE and
> +	 * V4L2_BUF_TYPE_VIDEO_OUTPUT, even if the device implements the MPLANE
> +	 * API. The V4L2 core will have converted the MPLANE variants to
> +	 * non-MPLANE.
> +	 * Open code this instead of using get_q_data in this case.
> +	 */
> +	if (ctx->dev->role != DECODE)
> +		return -ENOIOCTLCMD;
> +
> +	if (type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
> +		return -EINVAL;
> +
> +	*f = ctx->q_data[V4L2_M2M_DST].aspect_ratio;
> +
> +	return 0;
> +}
> +
> +static int vidioc_subscribe_evt(struct v4l2_fh *fh,
> +				const struct v4l2_event_subscription *sub)
> +{
> +	switch (sub->type) {
> +	case V4L2_EVENT_EOS:
> +		return v4l2_event_subscribe(fh, sub, 2, NULL);
> +	case V4L2_EVENT_SOURCE_CHANGE:
> +		return v4l2_src_change_event_subscribe(fh, sub);
> +	default:
> +		return v4l2_ctrl_subscribe_event(fh, sub);
> +	}
> +}
> +
> +static int bcm2835_codec_set_level_profile(struct bcm2835_codec_ctx *ctx,
> +					   struct v4l2_ctrl *ctrl)
> +{
> +	struct mmal_parameter_video_profile param;
> +	int param_size = sizeof(param);
> +	int ret;
> +
> +	/*
> +	 * Level and Profile are set via the same MMAL parameter.
> +	 * Retrieve the current settings and amend the one that has changed.
> +	 */
> +	ret = vchiq_mmal_port_parameter_get(ctx->dev->instance,
> +					    &ctx->component->output[0],
> +					    MMAL_PARAMETER_PROFILE,
> +					    &param,
> +					    &param_size);
> +	if (ret)
> +		return ret;
> +
> +	switch (ctrl->id) {
> +	case V4L2_CID_MPEG_VIDEO_H264_PROFILE:
> +		switch (ctrl->val) {
> +		case V4L2_MPEG_VIDEO_H264_PROFILE_BASELINE:
> +			param.profile = MMAL_VIDEO_PROFILE_H264_BASELINE;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_PROFILE_CONSTRAINED_BASELINE:
> +			param.profile =
> +				MMAL_VIDEO_PROFILE_H264_CONSTRAINED_BASELINE;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_PROFILE_MAIN:
> +			param.profile = MMAL_VIDEO_PROFILE_H264_MAIN;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_PROFILE_HIGH:
> +			param.profile = MMAL_VIDEO_PROFILE_H264_HIGH;
> +			break;
> +		default:
> +			/* Should never get here */
> +			break;
> +		}
> +		break;
> +
> +	case V4L2_CID_MPEG_VIDEO_H264_LEVEL:
> +		switch (ctrl->val) {
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_1_0:
> +			param.level = MMAL_VIDEO_LEVEL_H264_1;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_1B:
> +			param.level = MMAL_VIDEO_LEVEL_H264_1b;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_1_1:
> +			param.level = MMAL_VIDEO_LEVEL_H264_11;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_1_2:
> +			param.level = MMAL_VIDEO_LEVEL_H264_12;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_1_3:
> +			param.level = MMAL_VIDEO_LEVEL_H264_13;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_2_0:
> +			param.level = MMAL_VIDEO_LEVEL_H264_2;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_2_1:
> +			param.level = MMAL_VIDEO_LEVEL_H264_21;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_2_2:
> +			param.level = MMAL_VIDEO_LEVEL_H264_22;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_3_0:
> +			param.level = MMAL_VIDEO_LEVEL_H264_3;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_3_1:
> +			param.level = MMAL_VIDEO_LEVEL_H264_31;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_3_2:
> +			param.level = MMAL_VIDEO_LEVEL_H264_32;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_4_0:
> +			param.level = MMAL_VIDEO_LEVEL_H264_4;
> +			break;
> +		/*
> +		 * Note that the hardware spec is level 4.0. Levels above that
> +		 * are there for correctly encoding the headers and may not
> +		 * be able to keep up with real-time.
> +		 */
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_4_1:
> +			param.level = MMAL_VIDEO_LEVEL_H264_41;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_4_2:
> +			param.level = MMAL_VIDEO_LEVEL_H264_42;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_5_0:
> +			param.level = MMAL_VIDEO_LEVEL_H264_5;
> +			break;
> +		case V4L2_MPEG_VIDEO_H264_LEVEL_5_1:
> +			param.level = MMAL_VIDEO_LEVEL_H264_51;
> +			break;
> +		default:
> +			/* Should never get here */
> +			break;
> +		}
> +	}
> +	ret = vchiq_mmal_port_parameter_set(ctx->dev->instance,
> +					    &ctx->component->output[0],
> +					    MMAL_PARAMETER_PROFILE,
> +					    &param,
> +					    param_size);
> +
> +	return ret;
> +}
> +
> +static int bcm2835_codec_s_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +	struct bcm2835_codec_ctx *ctx =
> +		container_of(ctrl->handler, struct bcm2835_codec_ctx, hdl);
> +	int ret = 0;
> +
> +	if (ctrl->flags & V4L2_CTRL_FLAG_READ_ONLY)
> +		return 0;
> +
> +	switch (ctrl->id) {
> +	case V4L2_CID_MPEG_VIDEO_BITRATE:
> +		ctx->bitrate = ctrl->val;
> +		if (!ctx->component)
> +			break;
> +
> +		ret = vchiq_mmal_port_parameter_set(ctx->dev->instance,
> +						    &ctx->component->output[0],
> +						    MMAL_PARAMETER_VIDEO_BIT_RATE,
> +						    &ctrl->val,
> +						    sizeof(ctrl->val));
> +		break;
> +
> +	case V4L2_CID_MPEG_VIDEO_BITRATE_MODE: {
> +		u32 bitrate_mode;
> +
> +		if (!ctx->component)
> +			break;
> +
> +		switch (ctrl->val) {
> +		default:
> +		case V4L2_MPEG_VIDEO_BITRATE_MODE_VBR:
> +			bitrate_mode = MMAL_VIDEO_RATECONTROL_VARIABLE;
> +			break;
> +		case V4L2_MPEG_VIDEO_BITRATE_MODE_CBR:
> +			bitrate_mode = MMAL_VIDEO_RATECONTROL_CONSTANT;
> +			break;
> +		}
> +
> +		ret = vchiq_mmal_port_parameter_set(ctx->dev->instance,
> +						    &ctx->component->output[0],
> +						    MMAL_PARAMETER_RATECONTROL,
> +						    &bitrate_mode,
> +						    sizeof(bitrate_mode));
> +		break;
> +	}
> +	case V4L2_CID_MPEG_VIDEO_REPEAT_SEQ_HEADER:
> +		if (!ctx->component)
> +			break;
> +
> +		ret = vchiq_mmal_port_parameter_set(ctx->dev->instance,
> +						    &ctx->component->output[0],
> +						    MMAL_PARAMETER_VIDEO_ENCODE_INLINE_HEADER,
> +						    &ctrl->val,
> +						    sizeof(ctrl->val));
> +		break;
> +
> +	case V4L2_CID_MPEG_VIDEO_HEADER_MODE:
> +		if (!ctx->component)
> +			break;
> +
> +		ret = vchiq_mmal_port_parameter_set(ctx->dev->instance,
> +						    &ctx->component->output[0],
> +						    MMAL_PARAMETER_VIDEO_ENCODE_HEADERS_WITH_FRAME,
> +						    &ctrl->val,
> +						    sizeof(ctrl->val));
> +		break;
> +
> +	case V4L2_CID_MPEG_VIDEO_H264_I_PERIOD:
> +		/*
> +		 * Incorrect initial implementation meant that H264_I_PERIOD
> +		 * was implemented to control intra-I period. As the MMAL
> +		 * encoder never produces I-frames that aren't IDR frames, it
> +		 * should actually have been GOP_SIZE.
> +		 * Support both controls, but writing to H264_I_PERIOD will
> +		 * update GOP_SIZE.
> +		 */
> +		__v4l2_ctrl_s_ctrl(ctx->gop_size, ctrl->val);

Drop this this unless you decide to keep backward compatibility in general. It
may confuse users having one control change another, so perhaps keep both stored
separately, and then use the smallest in practice ?

> +	fallthrough;
> +	case V4L2_CID_MPEG_VIDEO_GOP_SIZE:
> +		if (!ctx->component)
> +			break;
> +
> +		ret = vchiq_mmal_port_parameter_set(ctx->dev->instance,
> +						    &ctx->component->output[0],
> +						    MMAL_PARAMETER_INTRAPERIOD,
> +						    &ctrl->val,
> +						    sizeof(ctrl->val));
> +		break;
> +
> +	case V4L2_CID_MPEG_VIDEO_H264_PROFILE:
> +	case V4L2_CID_MPEG_VIDEO_H264_LEVEL:
> +		if (!ctx->component)
> +			break;
> +
> +		ret = bcm2835_codec_set_level_profile(ctx, ctrl);
> +		break;
> +
> +	case V4L2_CID_MPEG_VIDEO_H264_MIN_QP:
> +		if (!ctx->component)
> +			break;
> +
> +		ret = vchiq_mmal_port_parameter_set(ctx->dev->instance,
> +						    &ctx->component->output[0],
> +						    MMAL_PARAMETER_VIDEO_ENCODE_MIN_QUANT,
> +						    &ctrl->val,
> +						    sizeof(ctrl->val));
> +		break;
> +
> +	case V4L2_CID_MPEG_VIDEO_H264_MAX_QP:
> +		if (!ctx->component)
> +			break;
> +
> +		ret = vchiq_mmal_port_parameter_set(ctx->dev->instance,
> +						    &ctx->component->output[0],
> +						    MMAL_PARAMETER_VIDEO_ENCODE_MAX_QUANT,
> +						    &ctrl->val,
> +						    sizeof(ctrl->val));
> +		break;
> +
> +	case V4L2_CID_MPEG_VIDEO_FORCE_KEY_FRAME: {
> +		u32 mmal_bool = 1;
> +
> +		if (!ctx->component)
> +			break;
> +
> +		ret = vchiq_mmal_port_parameter_set(ctx->dev->instance,
> +						    &ctx->component->output[0],
> +						    MMAL_PARAMETER_VIDEO_REQUEST_I_FRAME,
> +						    &mmal_bool,
> +						    sizeof(mmal_bool));
> +		break;
> +	}
> +	case V4L2_CID_HFLIP:
> +	case V4L2_CID_VFLIP: {
> +		u32 u32_value;
> +
> +		if (ctrl->id == V4L2_CID_HFLIP)
> +			ctx->hflip = ctrl->val;
> +		else
> +			ctx->vflip = ctrl->val;
> +
> +		if (!ctx->component)
> +			break;
> +
> +		if (ctx->hflip && ctx->vflip)
> +			u32_value = MMAL_PARAM_MIRROR_BOTH;
> +		else if (ctx->hflip)
> +			u32_value = MMAL_PARAM_MIRROR_HORIZONTAL;
> +		else if (ctx->vflip)
> +			u32_value = MMAL_PARAM_MIRROR_VERTICAL;
> +		else
> +			u32_value = MMAL_PARAM_MIRROR_NONE;
> +
> +		ret = vchiq_mmal_port_parameter_set(ctx->dev->instance,
> +						    &ctx->component->input[0],
> +						    MMAL_PARAMETER_MIRROR,
> +						    &u32_value,
> +						    sizeof(u32_value));
> +		break;
> +	}
> +	case V4L2_CID_MPEG_VIDEO_B_FRAMES:
> +		ret = 0;
> +		break;
> 

Wouldn't it be simpleer to not implement it at all ?

> +
> +	case V4L2_CID_JPEG_COMPRESSION_QUALITY:
> +		if (!ctx->component)
> +			break;
> +
> +		ret = vchiq_mmal_port_parameter_set(ctx->dev->instance,
> +						    &ctx->component->output[0],
> +						    MMAL_PARAMETER_JPEG_Q_FACTOR,
> +						    &ctrl->val,
> +						    sizeof(ctrl->val));
> +		break;
> +
> +	default:
> +		v4l2_err(&ctx->dev->v4l2_dev, "Invalid control %08x\n", ctrl->id);
> +		return -EINVAL;
> +	}
> +
> +	if (ret)
> +		v4l2_err(&ctx->dev->v4l2_dev, "Failed setting ctrl %08x, ret %d\n",
> +			 ctrl->id, ret);
> +	return ret ? -EINVAL : 0;
> +}
> +
> +static const struct v4l2_ctrl_ops bcm2835_codec_ctrl_ops = {
> +	.s_ctrl = bcm2835_codec_s_ctrl,
> +};
> +
> +static int vidioc_try_decoder_cmd(struct file *file, void *priv,
> +				  struct v4l2_decoder_cmd *cmd)
> +{
> +	struct bcm2835_codec_ctx *ctx = file2ctx(file);
> +
> +	if (ctx->dev->role != DECODE)
> +		return -EINVAL;
> +
> +	switch (cmd->cmd) {
> +	case V4L2_DEC_CMD_STOP:
> +		if (cmd->flags & V4L2_DEC_CMD_STOP_TO_BLACK) {
> +			v4l2_err(&ctx->dev->v4l2_dev, "%s: DEC cmd->flags=%u stop to black not supported",
> +				 __func__, cmd->flags);
> +			return -EINVAL;
> +		}
> +		break;
> +	case V4L2_DEC_CMD_START:
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +	return 0;
> +}
> +
> +static int vidioc_decoder_cmd(struct file *file, void *priv,
> +			      struct v4l2_decoder_cmd *cmd)
> +{
> +	struct bcm2835_codec_ctx *ctx = file2ctx(file);
> +	struct bcm2835_codec_q_data *q_data = &ctx->q_data[V4L2_M2M_SRC];
> +	struct vb2_queue *dst_vq;
> +	int ret;
> +
> +	v4l2_dbg(2, debug, &ctx->dev->v4l2_dev, "%s, cmd %u", __func__,
> +		 cmd->cmd);
> +	ret = vidioc_try_decoder_cmd(file, priv, cmd);
> +	if (ret)
> +		return ret;
> +
> +	switch (cmd->cmd) {
> +	case V4L2_DEC_CMD_STOP:
> +		if (q_data->eos_buffer_in_use)
> +			v4l2_err(&ctx->dev->v4l2_dev, "EOS buffers already in use\n");
> +		q_data->eos_buffer_in_use = true;
> +
> +		q_data->eos_buffer.mmal.buffer_size = 0;
> +		q_data->eos_buffer.mmal.length = 0;
> +		q_data->eos_buffer.mmal.mmal_flags =
> +						MMAL_BUFFER_HEADER_FLAG_EOS;
> +		q_data->eos_buffer.mmal.pts = 0;
> +		q_data->eos_buffer.mmal.dts = 0;
> +
> +		if (!ctx->component)
> +			break;
> +
> +		ret = vchiq_mmal_submit_buffer(ctx->dev->instance,
> +					       &ctx->component->input[0],
> +					       &q_data->eos_buffer.mmal);
> +		if (ret)
> +			v4l2_err(&ctx->dev->v4l2_dev,
> +				 "%s: EOS buffer submit failed %d\n",
> +				 __func__, ret);
> +
> +		break;
> +
> +	case V4L2_DEC_CMD_START:
> +		dst_vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx,
> +					 V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE);
> +		vb2_clear_last_buffer_dequeued(dst_vq);
> +		break;
> +
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int vidioc_try_encoder_cmd(struct file *file, void *priv,
> +				  struct v4l2_encoder_cmd *cmd)
> +{
> +	switch (cmd->cmd) {
> +	case V4L2_ENC_CMD_STOP:
> +		break;
> +
> +	case V4L2_ENC_CMD_START:
> +		/* Do we need to do anything here? */
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +	return 0;
> +}
> +
> +static int vidioc_encoder_cmd(struct file *file, void *priv,
> +			      struct v4l2_encoder_cmd *cmd)
> +{
> +	struct bcm2835_codec_ctx *ctx = file2ctx(file);
> +	struct bcm2835_codec_q_data *q_data = &ctx->q_data[V4L2_M2M_SRC];
> +	int ret;
> +
> +	v4l2_dbg(2, debug, &ctx->dev->v4l2_dev, "%s, cmd %u", __func__,
> +		 cmd->cmd);
> +	ret = vidioc_try_encoder_cmd(file, priv, cmd);
> +	if (ret)
> +		return ret;
> +
> +	switch (cmd->cmd) {
> +	case V4L2_ENC_CMD_STOP:
> +		if (q_data->eos_buffer_in_use)
> +			v4l2_err(&ctx->dev->v4l2_dev, "EOS buffers already in use\n");
> +		q_data->eos_buffer_in_use = true;
> +
> +		q_data->eos_buffer.mmal.buffer_size = 0;
> +		q_data->eos_buffer.mmal.length = 0;
> +		q_data->eos_buffer.mmal.mmal_flags =
> +						MMAL_BUFFER_HEADER_FLAG_EOS;
> +		q_data->eos_buffer.mmal.pts = 0;
> +		q_data->eos_buffer.mmal.dts = 0;
> +
> +		if (!ctx->component)
> +			break;
> +
> +		ret = vchiq_mmal_submit_buffer(ctx->dev->instance,
> +					       &ctx->component->input[0],
> +					       &q_data->eos_buffer.mmal);
> +		if (ret)
> +			v4l2_err(&ctx->dev->v4l2_dev,
> +				 "%s: EOS buffer submit failed %d\n",
> +				 __func__, ret);
> +
> +		break;
> +	case V4L2_ENC_CMD_START:
> +		/* Do we need to do anything here? */
> +		break;
> 

As the lower part is identical as the one for decoders, you may want to clear
the last buffer dequeued flag to ?

> +
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int vidioc_enum_framesizes(struct file *file, void *fh,
> +				  struct v4l2_frmsizeenum *fsize)
> +{
> +	struct bcm2835_codec_ctx *ctx = file2ctx(file);
> +	struct bcm2835_codec_fmt *fmt;
> +
> +	fmt = find_format_pix_fmt(fsize->pixel_format, file2ctx(file)->dev,
> +				  true);
> +	if (!fmt)
> +		fmt = find_format_pix_fmt(fsize->pixel_format,
> +					  file2ctx(file)->dev,
> +					  false);
> +
> +	if (!fmt)
> +		return -EINVAL;
> +
> +	if (fsize->index)
> +		return -EINVAL;
> +
> +	fsize->type = V4L2_FRMSIZE_TYPE_STEPWISE;
> +
> +	fsize->stepwise.min_width = MIN_W;
> +	fsize->stepwise.max_width = ctx->dev->max_w;
> +	fsize->stepwise.step_width = 2;
> +	fsize->stepwise.min_height = MIN_H;
> +	fsize->stepwise.max_height = ctx->dev->max_h;
> +	fsize->stepwise.step_height = 2;
> 

nit: you could use a define. I believe 2 is because you use 420/422 subsampling,
and don't have no 444 support ?

> +
> +	return 0;
> +}
> +
> +static const struct v4l2_ioctl_ops bcm2835_codec_ioctl_ops = {
> +	.vidioc_querycap	= vidioc_querycap,
> +
> +	.vidioc_enum_fmt_vid_cap = vidioc_enum_fmt_vid_cap,
> +	.vidioc_g_fmt_vid_cap_mplane	= vidioc_g_fmt_vid_cap,
> +	.vidioc_try_fmt_vid_cap_mplane	= vidioc_try_fmt_vid_cap,
> +	.vidioc_s_fmt_vid_cap_mplane	= vidioc_s_fmt_vid_cap,
> +
> +	.vidioc_enum_fmt_vid_out = vidioc_enum_fmt_vid_out,
> +	.vidioc_g_fmt_vid_out_mplane	= vidioc_g_fmt_vid_out,
> +	.vidioc_try_fmt_vid_out_mplane	= vidioc_try_fmt_vid_out,
> +	.vidioc_s_fmt_vid_out_mplane	= vidioc_s_fmt_vid_out,
> +
> +	.vidioc_reqbufs		= v4l2_m2m_ioctl_reqbufs,
> +	.vidioc_querybuf	= v4l2_m2m_ioctl_querybuf,
> +	.vidioc_qbuf		= v4l2_m2m_ioctl_qbuf,
> +	.vidioc_dqbuf		= v4l2_m2m_ioctl_dqbuf,
> +	.vidioc_prepare_buf	= v4l2_m2m_ioctl_prepare_buf,
> +	.vidioc_create_bufs	= v4l2_m2m_ioctl_create_bufs,
> +	.vidioc_expbuf		= v4l2_m2m_ioctl_expbuf,
> +
> +	.vidioc_streamon	= v4l2_m2m_ioctl_streamon,
> +	.vidioc_streamoff	= v4l2_m2m_ioctl_streamoff,
> +
> +	.vidioc_g_selection	= vidioc_g_selection,
> +	.vidioc_s_selection	= vidioc_s_selection,
> +
> +	.vidioc_g_parm		= vidioc_g_parm,
> +	.vidioc_s_parm		= vidioc_s_parm,
> +
> +	.vidioc_g_pixelaspect	= vidioc_g_pixelaspect,
> +
> +	.vidioc_subscribe_event = vidioc_subscribe_evt,
> +	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
> +
> +	.vidioc_decoder_cmd = vidioc_decoder_cmd,
> +	.vidioc_try_decoder_cmd = vidioc_try_decoder_cmd,
> +	.vidioc_encoder_cmd = vidioc_encoder_cmd,
> +	.vidioc_try_encoder_cmd = vidioc_try_encoder_cmd,
> +	.vidioc_enum_framesizes = vidioc_enum_framesizes,
> +};
> +
> +static int bcm2835_codec_create_component(struct bcm2835_codec_ctx *ctx)
> +{
> +	struct bcm2835_codec_dev *dev = ctx->dev;
> +	unsigned int enable = 1;
> +	int ret;
> +
> +	ret = vchiq_mmal_component_init(dev->instance, components[dev->role],
> +					&ctx->component);
> +	if (ret < 0) {
> +		v4l2_err(&dev->v4l2_dev, "%s: failed to create component %s\n",
> +			 __func__, components[dev->role]);
> +		return -ENOMEM;
> +	}
> +
> +	vchiq_mmal_port_parameter_set(dev->instance, &ctx->component->input[0],
> +				      MMAL_PARAMETER_ZERO_COPY, &enable,
> +				      sizeof(enable));
> +	vchiq_mmal_port_parameter_set(dev->instance, &ctx->component->output[0],
> +				      MMAL_PARAMETER_ZERO_COPY, &enable,
> +				      sizeof(enable));
> +
> +	if (dev->role == DECODE) {
> +		/*
> +		 * Disable firmware option that ensures decoded timestamps
> +		 * always increase.
> +		 */
> +		enable = 0;
> +		vchiq_mmal_port_parameter_set(dev->instance,
> +					      &ctx->component->output[0],
> +					      MMAL_PARAMETER_VIDEO_VALIDATE_TIMESTAMPS,
> +					      &enable,
> +					      sizeof(enable));
> +		/*
> +		 * Enable firmware option to stop on colourspace and pixel
> +		 * aspect ratio changed
> +		 */
> +		enable = 1;
> +		vchiq_mmal_port_parameter_set(dev->instance,
> +					      &ctx->component->control,
> +					      MMAL_PARAMETER_VIDEO_STOP_ON_PAR_COLOUR_CHANGE,
> +					      &enable,
> +					      sizeof(enable));
> +	} else if (dev->role == DEINTERLACE) {
> +		/* Select the default deinterlace algorithm. */
> +		int half_framerate = 0;
> +		int default_frame_interval = -1; /* don't interpolate */
> +		int frame_type = 5; /* 0=progressive, 3=TFF, 4=BFF, 5=see frame */
> +		int use_qpus = 0;
> +		enum mmal_parameter_imagefx effect =
> +			advanced_deinterlace && ctx->q_data[V4L2_M2M_SRC].crop_width <= 800 ?
> +			MMAL_PARAM_IMAGEFX_DEINTERLACE_ADV :
> +			MMAL_PARAM_IMAGEFX_DEINTERLACE_FAST;
> +		struct mmal_parameter_imagefx_parameters params = {
> +			.effect = effect,
> +			.num_effect_params = 4,
> +			.effect_parameter = { frame_type,
> +					      default_frame_interval,
> +					      half_framerate,
> +					      use_qpus },
> +		};
> +
> +		vchiq_mmal_port_parameter_set(dev->instance,
> +					      &ctx->component->output[0],
> +					      MMAL_PARAMETER_IMAGE_EFFECT_PARAMETERS,
> +					      &params,
> +					      sizeof(params));
> +
> +	} else if (dev->role == ENCODE_IMAGE) {
> +		enable = 0;
> +		vchiq_mmal_port_parameter_set(dev->instance,
> +					      &ctx->component->control,
> +					      MMAL_PARAMETER_EXIF_DISABLE,
> +					      &enable,
> +					      sizeof(enable));
> +		enable = 1;
> +		vchiq_mmal_port_parameter_set(dev->instance,
> +					      &ctx->component->output[0],
> +						  MMAL_PARAMETER_JPEG_IJG_SCALING,
> +					      &enable,
> +					      sizeof(enable));
> +	}
> +
> +	setup_mmal_port_format(ctx, &ctx->q_data[V4L2_M2M_SRC],
> +			       &ctx->component->input[0]);
> +	ctx->component->input[0].cb_ctx = ctx;
> +
> +	setup_mmal_port_format(ctx, &ctx->q_data[V4L2_M2M_DST],
> +			       &ctx->component->output[0]);
> +	ctx->component->output[0].cb_ctx = ctx;
> +
> +	ret = vchiq_mmal_port_set_format(dev->instance,
> +					 &ctx->component->input[0]);
> +	if (ret < 0) {
> +		v4l2_dbg(1, debug, &dev->v4l2_dev,
> +			 "%s: vchiq_mmal_port_set_format ip port failed\n",
> +			 __func__);
> +		goto destroy_component;
> +	}
> +
> +	ret = vchiq_mmal_port_set_format(dev->instance,
> +					 &ctx->component->output[0]);
> +	if (ret < 0) {
> +		v4l2_dbg(1, debug, &dev->v4l2_dev,
> +			 "%s: vchiq_mmal_port_set_format op port failed\n",
> +			 __func__);
> +		goto destroy_component;
> +	}
> +
> +	if (dev->role == ENCODE || dev->role == ENCODE_IMAGE) {
> +		u32 param = 1;
> +
> +		if (ctx->q_data[V4L2_M2M_SRC].sizeimage <
> +			ctx->component->output[0].minimum_buffer.size)
> +			v4l2_err(&dev->v4l2_dev, "buffer size mismatch sizeimage %u < min size %u\n",
> +				 ctx->q_data[V4L2_M2M_SRC].sizeimage,
> +				 ctx->component->output[0].minimum_buffer.size);
> +
> +		if (dev->role == ENCODE) {
> +			/* Enable SPS Timing header so framerate information is encoded
> +			 * in the H264 header.
> +			 */
> +			vchiq_mmal_port_parameter_set(ctx->dev->instance,
> +						      &ctx->component->output[0],
> +						      MMAL_PARAMETER_VIDEO_ENCODE_SPS_TIMING,
> +						      &param, sizeof(param));
> +
> +			/* Enable inserting headers into the first frame */
> +			vchiq_mmal_port_parameter_set(ctx->dev->instance,
> +						      &ctx->component->control,
> +						      MMAL_PARAMETER_VIDEO_ENCODE_HEADERS_WITH_FRAME,
> +						      &param, sizeof(param));
> +			/*
> +			 * Avoid fragmenting the buffers over multiple frames (unless
> +			 * the frame is bigger than the whole buffer)
> +			 */
> +			vchiq_mmal_port_parameter_set(ctx->dev->instance,
> +						      &ctx->component->control,
> +						      MMAL_PARAMETER_MINIMISE_FRAGMENTATION,
> +						      &param, sizeof(param));
> +		}
> +	} else {
> +		if (ctx->q_data[V4L2_M2M_DST].sizeimage <
> +			ctx->component->output[0].minimum_buffer.size)
> +			v4l2_err(&dev->v4l2_dev, "buffer size mismatch sizeimage %u < min size %u\n",
> +				 ctx->q_data[V4L2_M2M_DST].sizeimage,
> +				 ctx->component->output[0].minimum_buffer.size);
> +	}
> +
> +	/* Now we have a component we can set all the ctrls */
> +	ret = v4l2_ctrl_handler_setup(&ctx->hdl);
> +
> +	v4l2_dbg(2, debug, &dev->v4l2_dev, "%s: component created as %s\n",
> +		 __func__, components[dev->role]);
> +
> +	return 0;
> +
> +destroy_component:
> +	vchiq_mmal_component_finalise(ctx->dev->instance, ctx->component);
> +	ctx->component = NULL;
> +
> +	return ret;
> +}
> +
> +/*
> + * Queue operations
> + */
> +
> +static int bcm2835_codec_queue_setup(struct vb2_queue *vq,
> +				     unsigned int *nbuffers,
> +				     unsigned int *nplanes,
> +				     unsigned int sizes[],
> +				     struct device *alloc_devs[])
> +{
> +	struct bcm2835_codec_ctx *ctx = vb2_get_drv_priv(vq);
> +	struct bcm2835_codec_q_data *q_data;
> +	struct vchiq_mmal_port *port;
> +	unsigned int size;
> +
> +	q_data = get_q_data(ctx, vq->type);
> +	if (!q_data)
> +		return -EINVAL;
> +
> +	if (!ctx->component)
> +		if (bcm2835_codec_create_component(ctx))
> +			return -EINVAL;
> +
> +	port = get_port_data(ctx, vq->type);
> +
> +	size = q_data->sizeimage;
> +
> +	if (*nplanes)
> +		return sizes[0] < size ? -EINVAL : 0;
> +
> +	*nplanes = 1;
> +
> +	sizes[0] = size;
> +	port->current_buffer.size = size;
> +
> +	if (*nbuffers < port->minimum_buffer.num)
> +		*nbuffers = port->minimum_buffer.num;
> +	/* Add one buffer to take an EOS */
> +	port->current_buffer.num = *nbuffers + 1;
> +
> +	return 0;
> +}
> +
> +static int bcm2835_codec_mmal_buf_cleanup(struct mmal_buffer *mmal_buf)
> +{
> +	mmal_vchi_buffer_cleanup(mmal_buf);
> +
> +	if (mmal_buf->dma_buf) {
> +		dma_buf_put(mmal_buf->dma_buf);
> +		mmal_buf->dma_buf = NULL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int bcm2835_codec_buf_init(struct vb2_buffer *vb)
> +{
> +	struct bcm2835_codec_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
> +	struct vb2_v4l2_buffer *vb2 = to_vb2_v4l2_buffer(vb);
> +	struct v4l2_m2m_buffer *m2m = container_of(vb2, struct v4l2_m2m_buffer,
> +						   vb);
> +	struct m2m_mmal_buffer *buf = container_of(m2m, struct m2m_mmal_buffer,
> +						   m2m);
> +
> +	v4l2_dbg(2, debug, &ctx->dev->v4l2_dev, "%s: ctx:%p, vb %p\n",
> +		 __func__, ctx, vb);
> +	buf->mmal.buffer = vb2_plane_vaddr(&buf->m2m.vb.vb2_buf, 0);
> +	buf->mmal.buffer_size = vb2_plane_size(&buf->m2m.vb.vb2_buf, 0);
> +
> +	mmal_vchi_buffer_init(ctx->dev->instance, &buf->mmal);
> +
> +	return 0;
> +}
> +
> +static int bcm2835_codec_buf_prepare(struct vb2_buffer *vb)
> +{
> +	struct bcm2835_codec_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
> +	struct bcm2835_codec_q_data *q_data;
> +	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
> +	struct v4l2_m2m_buffer *m2m = container_of(vbuf, struct v4l2_m2m_buffer,
> +						   vb);
> +	struct m2m_mmal_buffer *buf = container_of(m2m, struct m2m_mmal_buffer,
> +						   m2m);
> +	struct dma_buf *dma_buf;
> +	int ret;
> +
> +	v4l2_dbg(4, debug, &ctx->dev->v4l2_dev, "%s: type: %d ptr %p\n",
> +		 __func__, vb->vb2_queue->type, vb);
> +
> +	q_data = get_q_data(ctx, vb->vb2_queue->type);
> +	if (V4L2_TYPE_IS_OUTPUT(vb->vb2_queue->type)) {
> +		if (vbuf->field == V4L2_FIELD_ANY)
> +			vbuf->field = V4L2_FIELD_NONE;
> +	}
> +
> +	if (vb2_plane_size(vb, 0) < q_data->sizeimage) {
> +		v4l2_err(&ctx->dev->v4l2_dev, "%s data will not fit into plane (%lu < %lu)\n",
> +			 __func__, vb2_plane_size(vb, 0),
> +			 (long)q_data->sizeimage);
> +		return -EINVAL;
> +	}
> +
> +	if (!V4L2_TYPE_IS_OUTPUT(vb->vb2_queue->type))
> +		vb2_set_plane_payload(vb, 0, q_data->sizeimage);
> +
> +	switch (vb->memory) {
> +	case VB2_MEMORY_DMABUF:
> +		dma_buf = dma_buf_get(vb->planes[0].m.fd);
> +
> +		if (dma_buf != buf->mmal.dma_buf) {
> +			/* dmabuf either hasn't already been mapped, or it has
> +			 * changed.
> +			 */
> +			if (buf->mmal.dma_buf) {
> +				v4l2_err(&ctx->dev->v4l2_dev,
> +					 "%s Buffer changed - why did the core not call cleanup?\n",
> +					 __func__);
> +				bcm2835_codec_mmal_buf_cleanup(&buf->mmal);
> +			}
> +
> +			buf->mmal.dma_buf = dma_buf;
> +		} else {
> +			/* We already have a reference count on the dmabuf, so
> +			 * release the one we acquired above.
> +			 */
> +			dma_buf_put(dma_buf);
> +		}
> +		ret = 0;
> +		break;
> +	case VB2_MEMORY_MMAP:
> +		/*
> +		 * We want to do this at init, but vb2_core_expbuf checks that
> +		 * the index < q->num_buffers, and q->num_buffers only gets
> +		 * updated once all the buffers are allocated.
> +		 */
> +		if (!buf->mmal.dma_buf) {
> +			buf->mmal.dma_buf = vb2_core_expbuf_dmabuf(vb->vb2_queue,
> +						     vb->vb2_queue->type,
> +						     vb, 0,
> +						     O_CLOEXEC);
> +			v4l2_dbg(3, debug, &ctx->dev->v4l2_dev,
> +				 "%s: exporting ptr %p to dmabuf %p\n",
> +				 __func__, vb, buf->mmal.dma_buf);
> +			if (IS_ERR(buf->mmal.dma_buf)) {
> +				ret = PTR_ERR(buf->mmal.dma_buf);
> +				v4l2_err(&ctx->dev->v4l2_dev,
> +					 "%s: Failed to expbuf idx %d, ret %d\n",
> +					 __func__, vb->index, ret);
> +			}
> +		} else {
> +			ret = 0;
> +		}
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +static void bcm2835_codec_buf_queue(struct vb2_buffer *vb)
> +{
> +	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
> +	struct bcm2835_codec_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
> +
> +	v4l2_dbg(4, debug, &ctx->dev->v4l2_dev, "%s: type: %d ptr %p vbuf->flags %u, seq %u, bytesused %u\n",
> +		 __func__, vb->vb2_queue->type, vb, vbuf->flags, vbuf->sequence,
> +		 vb->planes[0].bytesused);
> +	v4l2_m2m_buf_queue(ctx->fh.m2m_ctx, vbuf);
> +}
> +
> +static void bcm2835_codec_buffer_cleanup(struct vb2_buffer *vb)
> +{
> +	struct bcm2835_codec_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
> +	struct vb2_v4l2_buffer *vb2 = to_vb2_v4l2_buffer(vb);
> +	struct v4l2_m2m_buffer *m2m = container_of(vb2, struct v4l2_m2m_buffer,
> +						   vb);
> +	struct m2m_mmal_buffer *buf = container_of(m2m, struct m2m_mmal_buffer,
> +						   m2m);
> +
> +	v4l2_dbg(2, debug, &ctx->dev->v4l2_dev, "%s: ctx:%p, vb %p\n",
> +		 __func__, ctx, vb);
> +
> +	bcm2835_codec_mmal_buf_cleanup(&buf->mmal);
> +}
> +
> +static void bcm2835_codec_flush_buffers(struct bcm2835_codec_ctx *ctx,
> +					struct vchiq_mmal_port *port)
> +{
> +	int ret;
> +
> +	if (atomic_read(&port->buffers_with_vpu)) {
> +		v4l2_dbg(1, debug, &ctx->dev->v4l2_dev, "%s: Waiting for buffers to be returned - %d outstanding\n",
> +			 __func__, atomic_read(&port->buffers_with_vpu));
> +		ret = wait_for_completion_timeout(&ctx->frame_cmplt,
> +						  COMPLETE_TIMEOUT);
> +		if (ret <= 0) {
> +			v4l2_err(&ctx->dev->v4l2_dev, "%s: Timeout waiting for buffers to be returned - %d outstanding\n",
> +				 __func__,
> +				 atomic_read(&port->buffers_with_vpu));
> +		}
> +	}
> +}
> +static int bcm2835_codec_start_streaming(struct vb2_queue *q,
> +					 unsigned int count)
> +{
> +	struct bcm2835_codec_ctx *ctx = vb2_get_drv_priv(q);
> +	struct bcm2835_codec_dev *dev = ctx->dev;
> +	struct bcm2835_codec_q_data *q_data = get_q_data(ctx, q->type);
> +	struct vchiq_mmal_port *port = get_port_data(ctx, q->type);
> +	int ret = 0;
> +
> +	v4l2_dbg(1, debug, &ctx->dev->v4l2_dev, "%s: type: %d count %d\n",
> +		 __func__, q->type, count);
> +	q_data->sequence = 0;
> +
> +	if (!ctx->component_enabled) {
> +		ret = vchiq_mmal_component_enable(dev->instance,
> +						  ctx->component);
> +		if (ret)
> +			v4l2_err(&ctx->dev->v4l2_dev, "%s: Failed enabling component, ret %d\n",
> +				 __func__, ret);
> +		ctx->component_enabled = true;
> +	}
> +
> +	if (port->enabled) {
> +		unsigned int num_buffers;
> +
> +		init_completion(&ctx->frame_cmplt);
> +
> +		/*
> +		 * This should only ever happen with DECODE and the MMAL output
> +		 * port that has been enabled for resolution changed events.
> +		 * In this case no buffers have been allocated or sent to the
> +		 * component, so warn on that.
> +		 */
> +		WARN_ON(ctx->dev->role != DECODE);
> +		WARN_ON(q->type != V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE);
> +		WARN_ON(atomic_read(&port->buffers_with_vpu));
> +
> +		/*
> +		 * Disable will reread the port format, so retain buffer count.
> +		 */
> +		num_buffers = port->current_buffer.num;
> +
> +		ret = vchiq_mmal_port_disable(dev->instance, port);
> +		if (ret)
> +			v4l2_err(&ctx->dev->v4l2_dev, "%s: Error disabling port update buffer count, ret %d\n",
> +				 __func__, ret);
> +		bcm2835_codec_flush_buffers(ctx, port);
> +		port->current_buffer.num = num_buffers;
> +	}
> +
> +	if (count < port->minimum_buffer.num)
> +		count = port->minimum_buffer.num;
> +
> +	if (port->current_buffer.num < count + 1) {
> +		v4l2_dbg(2, debug, &ctx->dev->v4l2_dev, "%s: ctx:%p, buffer count changed %u to %u\n",
> +			 __func__, ctx, port->current_buffer.num, count + 1);
> +
> +		port->current_buffer.num = count + 1;
> +		ret = vchiq_mmal_port_set_format(dev->instance, port);
> +		if (ret)
> +			v4l2_err(&ctx->dev->v4l2_dev, "%s: Error updating buffer count, ret %d\n",
> +				 __func__, ret);
> +	}
> +
> +	if (dev->role == DECODE &&
> +	    q->type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE &&
> +	    !ctx->component->output[0].enabled) {
> +		/*
> +		 * Decode needs to enable the MMAL output/V4L2 CAPTURE
> +		 * port at this point too so that we have everything
> +		 * set up for dynamic resolution changes.
> +		 */
> +		ret = vchiq_mmal_port_enable(dev->instance,
> +					     &ctx->component->output[0],
> +					     op_buffer_cb);
> +		if (ret)
> +			v4l2_err(&ctx->dev->v4l2_dev, "%s: Failed enabling o/p port, ret %d\n",
> +				 __func__, ret);
> +	}
> +
> +	if (q->type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE) {
> +		/*
> +		 * Create the EOS buffer.
> +		 * We only need the MMAL part, and want to NOT attach a memory
> +		 * buffer to it as it should only take flags.
> +		 */
> +		memset(&q_data->eos_buffer, 0, sizeof(q_data->eos_buffer));
> +		mmal_vchi_buffer_init(dev->instance,
> +				      &q_data->eos_buffer.mmal);
> +		q_data->eos_buffer_in_use = false;
> +
> +		ret = vchiq_mmal_port_enable(dev->instance,
> +					     port,
> +					     ip_buffer_cb);
> +		if (ret)
> +			v4l2_err(&ctx->dev->v4l2_dev, "%s: Failed enabling i/p port, ret %d\n",
> +				 __func__, ret);
> +	} else {
> +		if (!port->enabled) {
> +			ret = vchiq_mmal_port_enable(dev->instance,
> +						     port,
> +						     op_buffer_cb);
> +			if (ret)
> +				v4l2_err(&ctx->dev->v4l2_dev, "%s: Failed enabling o/p port, ret %d\n",
> +					 __func__, ret);
> +		}
> +	}
> +	v4l2_dbg(1, debug, &ctx->dev->v4l2_dev, "%s: Done, ret %d\n",
> +		 __func__, ret);
> +	return ret;
> +}
> +
> +static void bcm2835_codec_stop_streaming(struct vb2_queue *q)
> +{
> +	struct bcm2835_codec_ctx *ctx = vb2_get_drv_priv(q);
> +	struct bcm2835_codec_dev *dev = ctx->dev;
> +	struct bcm2835_codec_q_data *q_data = get_q_data(ctx, q->type);
> +	struct vchiq_mmal_port *port = get_port_data(ctx, q->type);
> +	struct vb2_v4l2_buffer *vbuf;
> +	int ret;
> +
> +	v4l2_dbg(1, debug, &ctx->dev->v4l2_dev, "%s: type: %d - return buffers\n",
> +		 __func__, q->type);
> +
> +	init_completion(&ctx->frame_cmplt);
> +
> +	/* Clear out all buffers held by m2m framework */
> +	for (;;) {
> +		if (V4L2_TYPE_IS_OUTPUT(q->type))
> +			vbuf = v4l2_m2m_src_buf_remove(ctx->fh.m2m_ctx);
> +		else
> +			vbuf = v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx);
> +		if (!vbuf)
> +			break;
> +		v4l2_dbg(1, debug, &ctx->dev->v4l2_dev, "%s: return buffer %p\n",
> +			 __func__, vbuf);
> +
> +		v4l2_m2m_buf_done(vbuf, VB2_BUF_STATE_QUEUED);
> +	}
> +
> +	/* Disable MMAL port - this will flush buffers back */
> +	ret = vchiq_mmal_port_disable(dev->instance, port);
> +	if (ret)
> +		v4l2_err(&ctx->dev->v4l2_dev, "%s: Failed disabling %s port, ret %d\n",
> +			 __func__, V4L2_TYPE_IS_OUTPUT(q->type) ? "i/p" : "o/p",
> +			 ret);
> +
> +	bcm2835_codec_flush_buffers(ctx, port);
> +
> +	if (dev->role == DECODE &&
> +	    q->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE &&
> +	    ctx->component->input[0].enabled) {
> +		/*
> +		 * For decode we need to keep the MMAL output port enabled for
> +		 * resolution changed events whenever the input is enabled.
> +		 */
> +		ret = vchiq_mmal_port_enable(dev->instance,
> +					     &ctx->component->output[0],
> +					     op_buffer_cb);
> +		if (ret)
> +			v4l2_err(&ctx->dev->v4l2_dev, "%s: Failed enabling o/p port, ret %d\n",
> +				 __func__, ret);
> +	}
> +
> +	/* If both ports disabled, then disable the component */
> +	if (ctx->component_enabled &&
> +	    !ctx->component->input[0].enabled &&
> +	    !ctx->component->output[0].enabled) {
> +		ret = vchiq_mmal_component_disable(dev->instance,
> +						   ctx->component);
> +		if (ret)
> +			v4l2_err(&ctx->dev->v4l2_dev, "%s: Failed enabling component, ret %d\n",
> +				 __func__, ret);
> +		ctx->component_enabled = false;
> +	}
> +
> +	if (V4L2_TYPE_IS_OUTPUT(q->type))
> +		mmal_vchi_buffer_cleanup(&q_data->eos_buffer.mmal);
> +
> +	v4l2_dbg(1, debug, &ctx->dev->v4l2_dev, "%s: done\n", __func__);
> +}
> +
> +static const struct vb2_ops bcm2835_codec_qops = {
> +	.queue_setup	 = bcm2835_codec_queue_setup,
> +	.buf_init	 = bcm2835_codec_buf_init,
> +	.buf_prepare	 = bcm2835_codec_buf_prepare,
> +	.buf_queue	 = bcm2835_codec_buf_queue,
> +	.buf_cleanup	 = bcm2835_codec_buffer_cleanup,
> +	.start_streaming = bcm2835_codec_start_streaming,
> +	.stop_streaming  = bcm2835_codec_stop_streaming,
> +	.wait_prepare	 = vb2_ops_wait_prepare,
> +	.wait_finish	 = vb2_ops_wait_finish,
> +};
> +
> +static int queue_init(void *priv, struct vb2_queue *src_vq,
> +		      struct vb2_queue *dst_vq)
> +{
> +	struct bcm2835_codec_ctx *ctx = priv;
> +	int ret;
> +
> +	src_vq->type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
> +	src_vq->io_modes = VB2_MMAP | VB2_DMABUF;
> +	src_vq->drv_priv = ctx;
> +	src_vq->buf_struct_size = sizeof(struct m2m_mmal_buffer);
> +	src_vq->ops = &bcm2835_codec_qops;
> +	src_vq->mem_ops = &vb2_dma_contig_memops;
> +	src_vq->dev = &ctx->dev->device->dev;
> +	src_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
> +	src_vq->lock = &ctx->dev->dev_mutex;
> +
> +	ret = vb2_queue_init(src_vq);
> +	if (ret)
> +		return ret;
> +
> +	dst_vq->type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
> +	dst_vq->io_modes = VB2_MMAP | VB2_DMABUF;
> +	dst_vq->drv_priv = ctx;
> +	dst_vq->buf_struct_size = sizeof(struct m2m_mmal_buffer);
> +	dst_vq->ops = &bcm2835_codec_qops;
> +	dst_vq->mem_ops = &vb2_dma_contig_memops;
> +	dst_vq->dev = &ctx->dev->device->dev;
> +	dst_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
> +	dst_vq->lock = &ctx->dev->dev_mutex;
> +
> +	return vb2_queue_init(dst_vq);
> +}
> +
> +static void dec_add_profile_ctrls(struct bcm2835_codec_dev *const dev,
> +				  struct v4l2_ctrl_handler *const hdl)
> +{
> +	struct v4l2_ctrl *ctrl;
> +	unsigned int i;
> +	const struct bcm2835_codec_fmt_list *const list = &dev->supported_fmts[0];
> +
> +	for (i = 0; i < list->num_entries; ++i) {
> +		switch (list->list[i].fourcc) {
> +		case V4L2_PIX_FMT_H264:
> +			ctrl = v4l2_ctrl_new_std_menu(hdl, &bcm2835_codec_ctrl_ops,
> +						      V4L2_CID_MPEG_VIDEO_H264_LEVEL,
> +						      V4L2_MPEG_VIDEO_H264_LEVEL_4_2,
> +						      ~(BIT(V4L2_MPEG_VIDEO_H264_LEVEL_1_0) |
> +							BIT(V4L2_MPEG_VIDEO_H264_LEVEL_1B) |
> +							BIT(V4L2_MPEG_VIDEO_H264_LEVEL_1_1) |
> +							BIT(V4L2_MPEG_VIDEO_H264_LEVEL_1_2) |
> +							BIT(V4L2_MPEG_VIDEO_H264_LEVEL_1_3) |
> +							BIT(V4L2_MPEG_VIDEO_H264_LEVEL_2_0) |
> +							BIT(V4L2_MPEG_VIDEO_H264_LEVEL_2_1) |
> +							BIT(V4L2_MPEG_VIDEO_H264_LEVEL_2_2) |
> +							BIT(V4L2_MPEG_VIDEO_H264_LEVEL_3_0) |
> +							BIT(V4L2_MPEG_VIDEO_H264_LEVEL_3_1) |
> +							BIT(V4L2_MPEG_VIDEO_H264_LEVEL_3_2) |
> +							BIT(V4L2_MPEG_VIDEO_H264_LEVEL_4_0) |
> +							BIT(V4L2_MPEG_VIDEO_H264_LEVEL_4_1) |
> +							BIT(V4L2_MPEG_VIDEO_H264_LEVEL_4_2)),
> +						       V4L2_MPEG_VIDEO_H264_LEVEL_4_0);
> +			ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +			ctrl = v4l2_ctrl_new_std_menu(hdl, &bcm2835_codec_ctrl_ops,
> +						      V4L2_CID_MPEG_VIDEO_H264_PROFILE,
> +						      V4L2_MPEG_VIDEO_H264_PROFILE_HIGH,
> +						      ~(BIT(V4L2_MPEG_VIDEO_H264_PROFILE_BASELINE) |
> +							BIT(V4L2_MPEG_VIDEO_H264_PROFILE_CONSTRAINED_BASELINE) |
> +							BIT(V4L2_MPEG_VIDEO_H264_PROFILE_MAIN) |
> +							BIT(V4L2_MPEG_VIDEO_H264_PROFILE_HIGH)),
> +						       V4L2_MPEG_VIDEO_H264_PROFILE_HIGH);
> +			ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +			break;
> +		case V4L2_PIX_FMT_MPEG2:
> +			ctrl = v4l2_ctrl_new_std_menu(hdl, &bcm2835_codec_ctrl_ops,
> +						      V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL,
> +						      V4L2_MPEG_VIDEO_MPEG2_LEVEL_HIGH,
> +						      ~(BIT(V4L2_MPEG_VIDEO_MPEG2_LEVEL_LOW) |
> +							BIT(V4L2_MPEG_VIDEO_MPEG2_LEVEL_MAIN) |
> +							BIT(V4L2_MPEG_VIDEO_MPEG2_LEVEL_HIGH_1440) |
> +							BIT(V4L2_MPEG_VIDEO_MPEG2_LEVEL_HIGH)),
> +						      V4L2_MPEG_VIDEO_MPEG2_LEVEL_MAIN);
> +			ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +			ctrl = v4l2_ctrl_new_std_menu(hdl, &bcm2835_codec_ctrl_ops,
> +						      V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE,
> +						      V4L2_MPEG_VIDEO_MPEG2_PROFILE_MAIN,
> +						      ~(BIT(V4L2_MPEG_VIDEO_MPEG2_PROFILE_SIMPLE) |
> +							BIT(V4L2_MPEG_VIDEO_MPEG2_PROFILE_MAIN)),
> +						      V4L2_MPEG_VIDEO_MPEG2_PROFILE_MAIN);
> +			ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +			break;
> +		case V4L2_PIX_FMT_MPEG4:
> +			ctrl = v4l2_ctrl_new_std_menu(hdl, &bcm2835_codec_ctrl_ops,
> +						      V4L2_CID_MPEG_VIDEO_MPEG4_LEVEL,
> +						      V4L2_MPEG_VIDEO_MPEG4_LEVEL_5,
> +						      ~(BIT(V4L2_MPEG_VIDEO_MPEG4_LEVEL_0) |
> +							BIT(V4L2_MPEG_VIDEO_MPEG4_LEVEL_0B) |
> +							BIT(V4L2_MPEG_VIDEO_MPEG4_LEVEL_1) |
> +							BIT(V4L2_MPEG_VIDEO_MPEG4_LEVEL_2) |
> +							BIT(V4L2_MPEG_VIDEO_MPEG4_LEVEL_3) |
> +							BIT(V4L2_MPEG_VIDEO_MPEG4_LEVEL_3B) |
> +							BIT(V4L2_MPEG_VIDEO_MPEG4_LEVEL_4) |
> +							BIT(V4L2_MPEG_VIDEO_MPEG4_LEVEL_5)),
> +						      V4L2_MPEG_VIDEO_MPEG4_LEVEL_4);
> +			ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +			ctrl = v4l2_ctrl_new_std_menu(hdl, &bcm2835_codec_ctrl_ops,
> +						      V4L2_CID_MPEG_VIDEO_MPEG4_PROFILE,
> +						      V4L2_MPEG_VIDEO_MPEG4_PROFILE_ADVANCED_SIMPLE,
> +						      ~(BIT(V4L2_MPEG_VIDEO_MPEG4_PROFILE_SIMPLE) |
> +							BIT(V4L2_MPEG_VIDEO_MPEG4_PROFILE_ADVANCED_SIMPLE)),
> +						      V4L2_MPEG_VIDEO_MPEG4_PROFILE_ADVANCED_SIMPLE);
> +			ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +			break;
> +		/* No profiles defined by V4L2 */
> +		case V4L2_PIX_FMT_H263:
> +		case V4L2_PIX_FMT_JPEG:
> +		case V4L2_PIX_FMT_MJPEG:
> +		case V4L2_PIX_FMT_VC1_ANNEX_G:
> +		default:
> +			break;
> +		}
> +	}
> +}
> +
> +/*
> + * File operations
> + */
> +static int bcm2835_codec_open(struct file *file)
> +{
> +	struct bcm2835_codec_dev *dev = video_drvdata(file);
> +	struct bcm2835_codec_ctx *ctx = NULL;
> +	struct v4l2_ctrl_handler *hdl;
> +	int rc = 0;
> +
> +	if (mutex_lock_interruptible(&dev->dev_mutex)) {
> +		v4l2_err(&dev->v4l2_dev, "Mutex fail\n");
> +		return -ERESTARTSYS;
> +	}
> +	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
> +	if (!ctx) {
> +		rc = -ENOMEM;
> +		goto open_unlock;
> +	}
> +
> +	ctx->q_data[V4L2_M2M_SRC].fmt = get_default_format(dev, false);
> +	ctx->q_data[V4L2_M2M_DST].fmt = get_default_format(dev, true);
> +
> +	ctx->q_data[V4L2_M2M_SRC].crop_width = DEFAULT_WIDTH;
> +	ctx->q_data[V4L2_M2M_SRC].crop_height = DEFAULT_HEIGHT;
> +	ctx->q_data[V4L2_M2M_SRC].height = DEFAULT_HEIGHT;
> +	ctx->q_data[V4L2_M2M_SRC].bytesperline =
> +			get_bytesperline(DEFAULT_WIDTH, DEFAULT_HEIGHT,
> +					 ctx->q_data[V4L2_M2M_SRC].fmt,
> +					 dev->role);
> +	ctx->q_data[V4L2_M2M_SRC].sizeimage =
> +		get_sizeimage(ctx->q_data[V4L2_M2M_SRC].bytesperline,
> +			      ctx->q_data[V4L2_M2M_SRC].crop_width,
> +			      ctx->q_data[V4L2_M2M_SRC].height,
> +			      ctx->q_data[V4L2_M2M_SRC].fmt);
> +	ctx->q_data[V4L2_M2M_SRC].field = V4L2_FIELD_NONE;
> +
> +	ctx->q_data[V4L2_M2M_DST].crop_width = DEFAULT_WIDTH;
> +	ctx->q_data[V4L2_M2M_DST].crop_height = DEFAULT_HEIGHT;
> +	ctx->q_data[V4L2_M2M_DST].height = DEFAULT_HEIGHT;
> +	ctx->q_data[V4L2_M2M_DST].bytesperline =
> +			get_bytesperline(DEFAULT_WIDTH, DEFAULT_HEIGHT,
> +					 ctx->q_data[V4L2_M2M_DST].fmt,
> +					 dev->role);
> +	ctx->q_data[V4L2_M2M_DST].sizeimage =
> +		get_sizeimage(ctx->q_data[V4L2_M2M_DST].bytesperline,
> +			      ctx->q_data[V4L2_M2M_DST].crop_width,
> +			      ctx->q_data[V4L2_M2M_DST].height,
> +			      ctx->q_data[V4L2_M2M_DST].fmt);
> +	ctx->q_data[V4L2_M2M_DST].aspect_ratio.numerator = 1;
> +	ctx->q_data[V4L2_M2M_DST].aspect_ratio.denominator = 1;
> +	ctx->q_data[V4L2_M2M_DST].field = V4L2_FIELD_NONE;
> +
> +	ctx->colorspace = V4L2_COLORSPACE_REC709;
> +	ctx->bitrate = 10 * 1000 * 1000;
> +
> +	ctx->framerate_num = 30;
> +	ctx->framerate_denom = 1;
> +
> +	/* Initialise V4L2 contexts */
> +	v4l2_fh_init(&ctx->fh, video_devdata(file));
> +	file->private_data = &ctx->fh;
> +	ctx->dev = dev;
> +	hdl = &ctx->hdl;
> +	switch (dev->role) {
> +	case ENCODE:
> +	{
> +		/* Encode controls */
> +		v4l2_ctrl_handler_init(hdl, 13);
> +
> +		v4l2_ctrl_new_std_menu(hdl, &bcm2835_codec_ctrl_ops,
> +				       V4L2_CID_MPEG_VIDEO_BITRATE_MODE,
> +				       V4L2_MPEG_VIDEO_BITRATE_MODE_CBR, 0,
> +				       V4L2_MPEG_VIDEO_BITRATE_MODE_VBR);
> +		v4l2_ctrl_new_std(hdl, &bcm2835_codec_ctrl_ops,
> +				  V4L2_CID_MPEG_VIDEO_BITRATE,
> +				  25 * 1000, 25 * 1000 * 1000,
> +				  25 * 1000, 10 * 1000 * 1000);
> +		v4l2_ctrl_new_std_menu(hdl, &bcm2835_codec_ctrl_ops,
> +				       V4L2_CID_MPEG_VIDEO_HEADER_MODE,
> +				       V4L2_MPEG_VIDEO_HEADER_MODE_JOINED_WITH_1ST_FRAME,
> +				       0, V4L2_MPEG_VIDEO_HEADER_MODE_JOINED_WITH_1ST_FRAME);
> +		v4l2_ctrl_new_std(hdl, &bcm2835_codec_ctrl_ops,
> +				  V4L2_CID_MPEG_VIDEO_REPEAT_SEQ_HEADER,
> +				  0, 1,
> +				  1, 0);
> +		v4l2_ctrl_new_std(hdl, &bcm2835_codec_ctrl_ops,
> +				  V4L2_CID_MPEG_VIDEO_H264_I_PERIOD,
> +				  0, 0x7FFFFFFF,
> +				  1, 60);
> +		v4l2_ctrl_new_std_menu(hdl, &bcm2835_codec_ctrl_ops,
> +				       V4L2_CID_MPEG_VIDEO_H264_LEVEL,
> +				       V4L2_MPEG_VIDEO_H264_LEVEL_5_1,
> +				       ~(BIT(V4L2_MPEG_VIDEO_H264_LEVEL_1_0) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_LEVEL_1B) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_LEVEL_1_1) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_LEVEL_1_2) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_LEVEL_1_3) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_LEVEL_2_0) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_LEVEL_2_1) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_LEVEL_2_2) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_LEVEL_3_0) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_LEVEL_3_1) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_LEVEL_3_2) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_LEVEL_4_0) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_LEVEL_4_1) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_LEVEL_4_2) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_LEVEL_5_0) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_LEVEL_5_1)),
> +				       V4L2_MPEG_VIDEO_H264_LEVEL_4_0);
> +		v4l2_ctrl_new_std_menu(hdl, &bcm2835_codec_ctrl_ops,
> +				       V4L2_CID_MPEG_VIDEO_H264_PROFILE,
> +				       V4L2_MPEG_VIDEO_H264_PROFILE_HIGH,
> +				       ~(BIT(V4L2_MPEG_VIDEO_H264_PROFILE_BASELINE) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_PROFILE_CONSTRAINED_BASELINE) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_PROFILE_MAIN) |
> +					 BIT(V4L2_MPEG_VIDEO_H264_PROFILE_HIGH)),
> +					V4L2_MPEG_VIDEO_H264_PROFILE_HIGH);
> +		v4l2_ctrl_new_std(hdl, &bcm2835_codec_ctrl_ops,
> +				  V4L2_CID_MPEG_VIDEO_H264_MIN_QP,
> +				  0, 51,
> +				  1, 20);
> +		v4l2_ctrl_new_std(hdl, &bcm2835_codec_ctrl_ops,
> +				  V4L2_CID_MPEG_VIDEO_H264_MAX_QP,
> +				  0, 51,
> +				  1, 51);
> +		v4l2_ctrl_new_std(hdl, &bcm2835_codec_ctrl_ops,
> +				  V4L2_CID_MPEG_VIDEO_FORCE_KEY_FRAME,
> +				  0, 0, 0, 0);
> +		v4l2_ctrl_new_std(hdl, &bcm2835_codec_ctrl_ops,
> +				  V4L2_CID_MPEG_VIDEO_B_FRAMES,
> +				  0, 0,
> +				  1, 0);
> +		ctx->gop_size = v4l2_ctrl_new_std(hdl, &bcm2835_codec_ctrl_ops,
> +						  V4L2_CID_MPEG_VIDEO_GOP_SIZE,
> +						  0, 0x7FFFFFFF, 1, 60);
> +		if (hdl->error) {
> +			rc = hdl->error;
> +			goto free_ctrl_handler;
> +		}
> +		ctx->fh.ctrl_handler = hdl;
> +		v4l2_ctrl_handler_setup(hdl);
> +	}
> +	break;
> +	case DECODE:
> +	{
> +		v4l2_ctrl_handler_init(hdl, 1 + dev->supported_fmts[0].num_entries * 2);
> +
> +		v4l2_ctrl_new_std(hdl, &bcm2835_codec_ctrl_ops,
> +				  V4L2_CID_MIN_BUFFERS_FOR_CAPTURE,
> +				  1, 1, 1, 1);
> +		dec_add_profile_ctrls(dev, hdl);
> +		if (hdl->error) {
> +			rc = hdl->error;
> +			goto free_ctrl_handler;
> +		}
> +		ctx->fh.ctrl_handler = hdl;
> +		v4l2_ctrl_handler_setup(hdl);
> +	}
> +	break;
> +	case ISP:
> +	{
> +		v4l2_ctrl_handler_init(hdl, 2);
> +
> +		v4l2_ctrl_new_std(hdl, &bcm2835_codec_ctrl_ops,
> +				  V4L2_CID_HFLIP,
> +				  1, 0, 1, 0);
> +		v4l2_ctrl_new_std(hdl, &bcm2835_codec_ctrl_ops,
> +				  V4L2_CID_VFLIP,
> +				  1, 0, 1, 0);
> +		if (hdl->error) {
> +			rc = hdl->error;
> +			goto free_ctrl_handler;
> +		}
> +		ctx->fh.ctrl_handler = hdl;
> +		v4l2_ctrl_handler_setup(hdl);
> +	}
> +	break;
> +	case DEINTERLACE:
> +	{
> +		v4l2_ctrl_handler_init(hdl, 0);
> +	}
> +	break;
> +	case ENCODE_IMAGE:
> +	{
> +		/* Encode image controls */
> +		v4l2_ctrl_handler_init(hdl, 1);
> +
> +		v4l2_ctrl_new_std(hdl, &bcm2835_codec_ctrl_ops,
> +				  V4L2_CID_JPEG_COMPRESSION_QUALITY,
> +				  1, 100,
> +				  1, 80);
> +		if (hdl->error) {
> +			rc = hdl->error;
> +			goto free_ctrl_handler;
> +		}
> +		ctx->fh.ctrl_handler = hdl;
> +		v4l2_ctrl_handler_setup(hdl);
> +	}
> +	break;
> +	case NUM_ROLES:
> +	break;
> +	}
> +
> +	ctx->fh.m2m_ctx = v4l2_m2m_ctx_init(dev->m2m_dev, ctx, &queue_init);
> +
> +	if (IS_ERR(ctx->fh.m2m_ctx)) {
> +		rc = PTR_ERR(ctx->fh.m2m_ctx);
> +
> +		goto free_ctrl_handler;
> +	}
> +
> +	/* Set both queues as buffered as we have buffering in the VPU. That
> +	 * means that we will be scheduled whenever either an input or output
> +	 * buffer is available (otherwise one of each are required).
> +	 */
> +	v4l2_m2m_set_src_buffered(ctx->fh.m2m_ctx, true);
> +	v4l2_m2m_set_dst_buffered(ctx->fh.m2m_ctx, true);

Makes a lot of sense for this firmware (for all roles).

> +
> +	v4l2_fh_add(&ctx->fh);
> +	atomic_inc(&dev->num_inst);
> +
> +	mutex_unlock(&dev->dev_mutex);
> +	return 0;
> +
> +free_ctrl_handler:
> +	v4l2_ctrl_handler_free(hdl);
> +	kfree(ctx);
> +open_unlock:
> +	mutex_unlock(&dev->dev_mutex);
> +	return rc;
> +}
> +
> +static int bcm2835_codec_release(struct file *file)
> +{
> +	struct bcm2835_codec_dev *dev = video_drvdata(file);
> +	struct bcm2835_codec_ctx *ctx = file2ctx(file);
> +
> +	v4l2_dbg(1, debug, &dev->v4l2_dev, "%s: Releasing instance %p\n",
> +		 __func__, ctx);
> +
> +	v4l2_fh_del(&ctx->fh);
> +	v4l2_fh_exit(&ctx->fh);
> +	v4l2_ctrl_handler_free(&ctx->hdl);
> +	mutex_lock(&dev->dev_mutex);
> +	v4l2_m2m_ctx_release(ctx->fh.m2m_ctx);
> +
> +	if (ctx->component)
> +		vchiq_mmal_component_finalise(dev->instance, ctx->component);
> +
> +	mutex_unlock(&dev->dev_mutex);
> +	kfree(ctx);
> +
> +	atomic_dec(&dev->num_inst);
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_file_operations bcm2835_codec_fops = {
> +	.owner		= THIS_MODULE,
> +	.open		= bcm2835_codec_open,
> +	.release	= bcm2835_codec_release,
> +	.poll		= v4l2_m2m_fop_poll,
> +	.unlocked_ioctl	= video_ioctl2,
> +	.mmap		= v4l2_m2m_fop_mmap,
> +};
> +
> +static const struct video_device bcm2835_codec_videodev = {
> +	.name		= MEM2MEM_NAME,
> +	.vfl_dir	= VFL_DIR_M2M,
> +	.fops		= &bcm2835_codec_fops,
> +	.ioctl_ops	= &bcm2835_codec_ioctl_ops,
> +	.minor		= -1,
> +	.release	= video_device_release_empty,
> +};
> +
> +static const struct v4l2_m2m_ops m2m_ops = {
> +	.device_run	= device_run,
> +	.job_ready	= job_ready,
> +	.job_abort	= job_abort,
> +};
> +
> +/* Size of the array to provide to the VPU when asking for the list of supported
> + * formats.
> + * The ISP component currently advertises 62 input formats, so add a small
> + * overhead on that.
> + */
> +#define MAX_SUPPORTED_ENCODINGS 70
> +
> +/* Populate dev->supported_fmts with the formats supported by those ports. */
> +static int bcm2835_codec_get_supported_fmts(struct bcm2835_codec_dev *dev)
> +{
> +	struct bcm2835_codec_fmt *list;
> +	struct vchiq_mmal_component *component;
> +	u32 fourccs[MAX_SUPPORTED_ENCODINGS];
> +	u32 param_size = sizeof(fourccs);
> +	unsigned int i, j, num_encodings;
> +	int ret;
> +
> +	ret = vchiq_mmal_component_init(dev->instance, components[dev->role],
> +					&component);
> +	if (ret < 0) {
> +		v4l2_err(&dev->v4l2_dev, "%s: failed to create component %s\n",
> +			 __func__, components[dev->role]);
> +		return -ENOMEM;
> +	}
> +
> +	ret = vchiq_mmal_port_parameter_get(dev->instance,
> +					    &component->input[0],
> +					    MMAL_PARAMETER_SUPPORTED_ENCODINGS,
> +					    &fourccs,
> +					    &param_size);
> +
> +	if (ret) {
> +		if (ret == MMAL_MSG_STATUS_ENOSPC) {
> +			v4l2_err(&dev->v4l2_dev,
> +				 "%s: port has more encodings than we provided space for. Some are dropped (%zu vs %u).\n",
> +				 __func__, param_size / sizeof(u32),
> +				 MAX_SUPPORTED_ENCODINGS);
> +			num_encodings = MAX_SUPPORTED_ENCODINGS;
> +		} else {
> +			v4l2_err(&dev->v4l2_dev, "%s: get_param ret %u.\n",
> +				 __func__, ret);
> +			ret = -EINVAL;
> +			goto destroy_component;
> +		}
> +	} else {
> +		num_encodings = param_size / sizeof(u32);
> +	}
> +
> +	/* Assume at this stage that all encodings will be supported in V4L2.
> +	 * Any that aren't supported will waste a very small amount of memory.
> +	 */
> +	list = devm_kzalloc(&dev->device->dev,
> +			    sizeof(struct bcm2835_codec_fmt) * num_encodings,
> +			    GFP_KERNEL);
> +	if (!list) {
> +		ret = -ENOMEM;
> +		goto destroy_component;
> +	}
> +	dev->supported_fmts[0].list = list;
> +
> +	for (i = 0, j = 0; i < num_encodings; i++) {
> +		const struct bcm2835_codec_fmt *fmt = get_fmt(fourccs[i]);
> +
> +		if (fmt) {
> +			list[j] = *fmt;
> +			j++;
> +		}
> +	}
> +	dev->supported_fmts[0].num_entries = j;
> +
> +	param_size = sizeof(fourccs);
> +	ret = vchiq_mmal_port_parameter_get(dev->instance,
> +					    &component->output[0],
> +					    MMAL_PARAMETER_SUPPORTED_ENCODINGS,
> +					    &fourccs,
> +					    &param_size);
> +
> +	if (ret) {
> +		if (ret == MMAL_MSG_STATUS_ENOSPC) {
> +			v4l2_err(&dev->v4l2_dev,
> +				 "%s: port has more encodings than we provided space for. Some are dropped (%zu vs %u).\n",
> +				 __func__, param_size / sizeof(u32),
> +				 MAX_SUPPORTED_ENCODINGS);
> +			num_encodings = MAX_SUPPORTED_ENCODINGS;
> +		} else {
> +			ret = -EINVAL;
> +			goto destroy_component;
> +		}
> +	} else {
> +		num_encodings = param_size / sizeof(u32);
> +	}
> +	/* Assume at this stage that all encodings will be supported in V4L2. */
> +	list = devm_kzalloc(&dev->device->dev,
> +			    sizeof(struct bcm2835_codec_fmt) * num_encodings,
> +			    GFP_KERNEL);
> +	if (!list) {
> +		ret = -ENOMEM;
> +		goto destroy_component;
> +	}
> +	dev->supported_fmts[1].list = list;
> +
> +	for (i = 0, j = 0; i < num_encodings; i++) {
> +		const struct bcm2835_codec_fmt *fmt = get_fmt(fourccs[i]);
> +
> +		if (fmt) {
> +			list[j] = *fmt;
> +			j++;
> +		}
> +	}
> +	dev->supported_fmts[1].num_entries = j;
> +
> +	ret = 0;
> +
> +destroy_component:
> +	vchiq_mmal_component_finalise(dev->instance, component);
> +
> +	return ret;
> +}
> +
> +static int bcm2835_codec_create(struct bcm2835_codec_driver *drv,
> +				struct bcm2835_codec_dev **new_dev,
> +				enum bcm2835_codec_role role)
> +{
> +	struct vchiq_device *device = drv->device;
> +	struct bcm2835_codec_dev *dev;
> +	struct video_device *vfd;
> +	int function;
> +	int video_nr;
> +	int ret;
> +
> +	dev = devm_kzalloc(&device->dev, sizeof(*dev), GFP_KERNEL);
> +	if (!dev)
> +		return -ENOMEM;
> +
> +	dev->device = device;
> +
> +	dev->role = role;
> +
> +	ret = vchiq_mmal_init(&dev->instance);
> +	if (ret)
> +		return ret;
> +
> +	ret = bcm2835_codec_get_supported_fmts(dev);
> +	if (ret)
> +		goto vchiq_finalise;
> +
> +	atomic_set(&dev->num_inst, 0);
> +	mutex_init(&dev->dev_mutex);
> +
> +	/* Initialise the video device */
> +	dev->vfd = bcm2835_codec_videodev;
> +
> +	vfd = &dev->vfd;
> +	vfd->lock = &dev->dev_mutex;
> +	vfd->v4l2_dev = &dev->v4l2_dev;
> +	vfd->device_caps = V4L2_CAP_VIDEO_M2M_MPLANE | V4L2_CAP_STREAMING;
> +	vfd->v4l2_dev->mdev = &drv->mdev;
> +
> +	ret = v4l2_device_register(&device->dev, &dev->v4l2_dev);
> +	if (ret)
> +		goto vchiq_finalise;
> +
> +	dev->max_w = MAX_W_CODEC;
> +	dev->max_h = MAX_H_CODEC;
> +
> +	switch (role) {
> +	case DECODE:
> +		v4l2_disable_ioctl(vfd, VIDIOC_ENCODER_CMD);
> +		v4l2_disable_ioctl(vfd, VIDIOC_TRY_ENCODER_CMD);
> +		v4l2_disable_ioctl(vfd, VIDIOC_S_PARM);
> +		v4l2_disable_ioctl(vfd, VIDIOC_G_PARM);
> +		function = MEDIA_ENT_F_PROC_VIDEO_DECODER;
> +		video_nr = decode_video_nr;
> +		break;
> +	case ENCODE:
> +		v4l2_disable_ioctl(vfd, VIDIOC_DECODER_CMD);
> +		v4l2_disable_ioctl(vfd, VIDIOC_TRY_DECODER_CMD);
> +		function = MEDIA_ENT_F_PROC_VIDEO_ENCODER;
> +		video_nr = encode_video_nr;
> +		break;
> +	case ISP:
> +		v4l2_disable_ioctl(vfd, VIDIOC_DECODER_CMD);
> +		v4l2_disable_ioctl(vfd, VIDIOC_TRY_DECODER_CMD);
> +		v4l2_disable_ioctl(vfd, VIDIOC_S_PARM);
> +		v4l2_disable_ioctl(vfd, VIDIOC_G_PARM);
> +		function = MEDIA_ENT_F_PROC_VIDEO_SCALER;

Strictly speaking, this is also a pixel format converter, should we add 2
virtual entity to express this ?

> +		video_nr = isp_video_nr;
> +		dev->max_w = MAX_W_ISP;
> +		dev->max_h = MAX_H_ISP;
> +		break;
> +	case DEINTERLACE:
> +		v4l2_disable_ioctl(vfd, VIDIOC_DECODER_CMD);
> +		v4l2_disable_ioctl(vfd, VIDIOC_TRY_DECODER_CMD);
> +		v4l2_disable_ioctl(vfd, VIDIOC_S_PARM);
> +		v4l2_disable_ioctl(vfd, VIDIOC_G_PARM);
> +		function = MEDIA_ENT_F_PROC_VIDEO_PIXEL_FORMATTER;

Its rare that stateful drivers implement a media controller, but now that you
do, can we introduce proper functions for deinterlacer ? This would be extremely
handy to standardise upon, since they are not 1:1, hence more complex userspace
is needed (the reason why v4l2transform does not work).

> +		video_nr = deinterlace_video_nr;
> +		break;
> +	case ENCODE_IMAGE:
> +		v4l2_disable_ioctl(vfd, VIDIOC_DECODER_CMD);
> +		v4l2_disable_ioctl(vfd, VIDIOC_TRY_DECODER_CMD);
> +		function = MEDIA_ENT_F_PROC_VIDEO_ENCODER;
> +		video_nr = encode_image_nr;
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		goto unreg_dev;
> +	}
> +
> +	ret = video_register_device(vfd, VFL_TYPE_VIDEO, video_nr);
> +	if (ret) {
> +		v4l2_err(&dev->v4l2_dev, "Failed to register video device\n");
> +		goto unreg_dev;
> +	}
> +
> +	video_set_drvdata(vfd, dev);
> +	snprintf(vfd->name, sizeof(vfd->name), "%s-%s",
> +		 bcm2835_codec_videodev.name, roles[role]);
> +	v4l2_info(&dev->v4l2_dev, "Device registered as /dev/video%d\n",
> +		  vfd->num);
> +
> +	*new_dev = dev;
> +
> +	dev->m2m_dev = v4l2_m2m_init(&m2m_ops);
> +	if (IS_ERR(dev->m2m_dev)) {
> +		v4l2_err(&dev->v4l2_dev, "Failed to init mem2mem device\n");
> +		ret = PTR_ERR(dev->m2m_dev);
> +		goto err_m2m;
> +	}
> +
> +	ret = v4l2_m2m_register_media_controller(dev->m2m_dev, vfd, function);
> +	if (ret)
> +		goto err_m2m;
> +
> +	v4l2_info(&dev->v4l2_dev, "Loaded V4L2 %s\n",
> +		  roles[role]);
> +	return 0;
> +
> +err_m2m:
> +	v4l2_m2m_release(dev->m2m_dev);
> +	video_unregister_device(&dev->vfd);
> +unreg_dev:
> +	v4l2_device_unregister(&dev->v4l2_dev);
> +vchiq_finalise:
> +	vchiq_mmal_finalise(dev->instance);
> +	return ret;
> +}
> +
> +static int bcm2835_codec_destroy(struct bcm2835_codec_dev *dev)
> +{
> +	if (!dev)
> +		return -ENODEV;
> +
> +	v4l2_info(&dev->v4l2_dev, "Removing " MEM2MEM_NAME ", %s\n",
> +		  roles[dev->role]);
> +	v4l2_m2m_unregister_media_controller(dev->m2m_dev);
> +	v4l2_m2m_release(dev->m2m_dev);
> +	video_unregister_device(&dev->vfd);
> +	v4l2_device_unregister(&dev->v4l2_dev);
> +	vchiq_mmal_finalise(dev->instance);
> +
> +	return 0;
> +}
> +
> +static int bcm2835_codec_probe(struct vchiq_device *device)
> +{
> +	struct bcm2835_codec_driver *drv;
> +	struct media_device *mdev;
> +	int ret = 0;
> +
> +	drv = devm_kzalloc(&device->dev, sizeof(*drv), GFP_KERNEL);
> +	if (!drv)
> +		return -ENOMEM;
> +
> +	drv->device = device;
> +	mdev = &drv->mdev;
> +	mdev->dev = &device->dev;
> +
> +	strscpy(mdev->model, "bcm2835-codec", sizeof(mdev->model));
> +	strscpy(mdev->bus_info, "platform:bcm2835-codec",
> +		sizeof(mdev->bus_info));
> +
> +	/* This should return the vgencmd version information or such .. */
> +	mdev->hw_revision = 1;
> +	media_device_init(mdev);
> +
> +	ret = bcm2835_codec_create(drv, &drv->decode, DECODE);
> +	if (ret)
> +		goto out;
> +
> +	ret = bcm2835_codec_create(drv, &drv->encode, ENCODE);
> +	if (ret)
> +		goto out;
> +
> +	ret = bcm2835_codec_create(drv, &drv->isp, ISP);
> +	if (ret)
> +		goto out;
> +
> +	ret = bcm2835_codec_create(drv, &drv->deinterlace, DEINTERLACE);
> +	if (ret)
> +		goto out;
> +
> +	ret = bcm2835_codec_create(drv, &drv->encode_image, ENCODE_IMAGE);
> +	if (ret)
> +		goto out;
> +
> +	/* Register the media device node */
> +	if (media_device_register(mdev) < 0)
> +		goto out;
> +
> +	vchiq_set_drvdata(device, drv);
> +
> +	return 0;
> +
> +out:
> +	if (drv->encode_image) {
> +		bcm2835_codec_destroy(drv->encode_image);
> +		drv->encode_image = NULL;
> +	}
> +	if (drv->deinterlace) {
> +		bcm2835_codec_destroy(drv->deinterlace);
> +		drv->deinterlace = NULL;
> +	}
> +	if (drv->isp) {
> +		bcm2835_codec_destroy(drv->isp);
> +		drv->isp = NULL;
> +	}
> +	if (drv->encode) {
> +		bcm2835_codec_destroy(drv->encode);
> +		drv->encode = NULL;
> +	}
> +	if (drv->decode) {
> +		bcm2835_codec_destroy(drv->decode);
> +		drv->decode = NULL;
> +	}
> +	return ret;
> +}
> +
> +static void bcm2835_codec_remove(struct vchiq_device *device)
> +{
> +	struct bcm2835_codec_driver *drv = vchiq_get_drvdata(device);
> +
> +	media_device_unregister(&drv->mdev);
> +
> +	bcm2835_codec_destroy(drv->encode_image);
> +
> +	bcm2835_codec_destroy(drv->deinterlace);
> +
> +	bcm2835_codec_destroy(drv->isp);
> +
> +	bcm2835_codec_destroy(drv->encode);
> +
> +	bcm2835_codec_destroy(drv->decode);
> +
> +	media_device_cleanup(&drv->mdev);
> +}
> +
> +static struct vchiq_device_id device_id_table[] = {
> +        { .name = "bcm2835-codec" },
> +        {}
> +};
> +MODULE_DEVICE_TABLE(vchiq, device_id_table);
> +
> +static struct vchiq_driver bcm2835_v4l2_codec = {
> +	.probe = bcm2835_codec_probe,
> +	.remove = bcm2835_codec_remove,
> +	.id_table = device_id_table,
> +	.driver = {
> +		   .name = BCM2835_V4L_CODEC_NAME,
> +	},
> +};
> +
> +module_vchiq_driver(bcm2835_v4l2_codec);
> +
> +MODULE_DESCRIPTION("BCM2835 codec V4L2 driver");
> +MODULE_AUTHOR("Dave Stevenson, <dave.stevenson@xxxxxxxxxxxxxxx>");
> +MODULE_LICENSE("GPL");
> +MODULE_VERSION("0.0.1");
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
> index eb15aa011a22..a6764dfd57f2 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
> @@ -74,6 +74,7 @@ struct vchiq_state g_state;
>   */
>  static struct vchiq_device *bcm2835_audio;
>  static struct vchiq_device *bcm2835_camera;
> +static struct vchiq_device *bcm2835_codec;
>  static struct vchiq_device *bcm2835_isp;
>  static struct vchiq_device *vcsm_cma;
>  
> @@ -1856,6 +1857,7 @@ static int vchiq_probe(struct platform_device *pdev)
>  	vcsm_cma = vchiq_device_register(&pdev->dev, "vcsm-cma");
>  	bcm2835_audio = vchiq_device_register(&pdev->dev, "bcm2835-audio");
>  	bcm2835_camera = vchiq_device_register(&pdev->dev, "bcm2835-camera");
> +	bcm2835_codec = vchiq_device_register(&pdev->dev, "bcm2835-codec");
>  	bcm2835_isp = vchiq_device_register(&pdev->dev, "bcm2835-isp");
>  
>  	return 0;
> @@ -1870,6 +1872,7 @@ static void vchiq_remove(struct platform_device *pdev)
>  {
>  	vchiq_device_unregister(bcm2835_audio);
>  	vchiq_device_unregister(bcm2835_camera);
> +	vchiq_device_unregister(bcm2835_codec);
>  	vchiq_device_unregister(bcm2835_isp);
>  	vchiq_device_unregister(vcsm_cma);
>  	vchiq_debugfs_deinit();
> diff --git a/drivers/staging/vc04_services/vchiq-mmal/mmal-parameters.h b/drivers/staging/vc04_services/vchiq-mmal/mmal-parameters.h
> index 5007625981a7..729b3d6f3021 100644
> --- a/drivers/staging/vc04_services/vchiq-mmal/mmal-parameters.h
> +++ b/drivers/staging/vc04_services/vchiq-mmal/mmal-parameters.h
> @@ -223,6 +223,8 @@ enum mmal_parameter_camera_type {
>  	MMAL_PARAMETER_SHUTTER_SPEED,
>  		/**< Takes a @ref MMAL_PARAMETER_AWB_GAINS_T */
>  	MMAL_PARAMETER_CUSTOM_AWB_GAINS,
> +		/**< Takes a @ref MMAL_PARAMETER_BOOLEAN_T */
> +	MMAL_PARAMETER_JPEG_IJG_SCALING,
>  		/**< Takes a @ref MMAL_PARAMETER_CAMERA_SETTINGS_T */
>  	MMAL_PARAMETER_CAMERA_SETTINGS,
>  		/**< Takes a @ref MMAL_PARAMETER_PRIVACY_INDICATOR_T */
> @@ -674,6 +676,12 @@ enum mmal_parameter_video_type {
>  
>  	/**< Take a @ref MMAL_PARAMETER_BOOLEAN_T */
>  	MMAL_PARAMETER_VIDEO_ENCODE_HEADERS_WITH_FRAME,
> +
> +	/**< Take a @ref MMAL_PARAMETER_BOOLEAN_T */
> +	MMAL_PARAMETER_VIDEO_VALIDATE_TIMESTAMPS,
> +
> +	/**< Takes a @ref MMAL_PARAMETER_BOOLEAN_T */
> +	MMAL_PARAMETER_VIDEO_STOP_ON_PAR_COLOUR_CHANGE,
>  };
>  
>  /** Valid mirror modes */

Overall, I'm not a big fan of the roles, this could certainly be improved, but
read this as my personal view. M2M jobs lifetime don't match driver activity,
but such is the case for most stateful driver (except wave5). I haven't seen
power management, is that entirely handled by the firmware ?

One thing you are missing is a TODO for this driver to get out of staging. We
don't want to keep drivers in staging forever. The TODO is meant to be an agreed
set of changes needed to move it.

thanks for working on this,
Nicolas





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