Re: [PATCH v7 11/16] media: ti: j721e-csi2rx: add multistream support

[Rishikesh Donadkar]

On 07/10/25 17:22, Jai Luthra wrote:
> Hi Tomi,
>
> Quoting Tomi Valkeinen (2025-09-25 17:47:38)
> > Hi,
> >
> > On 11/09/2025 13:28, Rishikesh Donadkar wrote:
> > > From: Jai Luthra <j-luthra@xxxxxx>
> > >
> > > Each CSI2 stream can be multiplexed into 4 independent streams, each
> > > identified by its virtual channel number. To capture this multiplexed
> > The split can also be done with the datatype. I don't see it supported
> > in the driver, but afaics the HW supports it. Was there a reason not to
> > support DT filtering? I would think it would be very simple addition.
> I believe DT filtering should work as-is with the current driver, given we
> program the SHIM DMACNTX register with the correct datatype depending upon
> the v4l2 format of the video node.
>
> So if there is multi-stream source with two different datatypes, it should
> be possible to route it to different video devices and it "just" works. But
> I agree that it would be good if it can be tested once, and this commit
> message can mention that both VC and DT based filtering is supported.
>
> Rishikesh, would you be able to use an IMX219 to test capturing embedded
> data and frame data?


Yes, DT filtering works. I tried hard coding 0x12 (CSI DT for embedded 
data) in the DATTYP_CFG field of the DMACNTX_J register and captured 
frames from IMX219 using yavta and viewed that using xxd. I can see 
first few lines are that of embedded data, I can see the tags as 
mentioned in the 'CSI-2 Embedded Data Line' section of the IMX219 
datasheet[1]. I will mention this in the commit message as well.


[1] : https://www.opensourceinstruments.com/Electronics/Data/IMX219PQ.pdf


Thanks,

Rishikesh

> >   Tomi
> Thanks,
>      Jai
>
> > > stream, the application needs to tell the driver how it wants to route
> > > the data. It needs to specify which context should process which stream.
> > > This is done via the new routing APIs.
> > >
> > > Add ioctls to accept routing information from the application and save
> > > that in the driver. This can be used when starting streaming on a
> > > context to determine which route and consequently which virtual channel
> > > it should process.
> > >
> > > Support the new enable_stream()/disable_stream() APIs in the subdev
> > > instead of s_stream() hook.
> > >
> > > De-assert the pixel interface reset on first start_streaming() and assert
> > > it on the last stop_streaming().
> > >
> > > Reviewed-by: Yemike Abhilash Chandra <y-abhilashchandra@xxxxxx>
> > > Co-developed-by: Pratyush Yadav <p.yadav@xxxxxx>
> > > Signed-off-by: Pratyush Yadav <p.yadav@xxxxxx>
> > > Signed-off-by: Jai Luthra <j-luthra@xxxxxx>
> > > Co-developed-by: Rishikesh Donadkar <r-donadkar@xxxxxx>
> > > Signed-off-by: Rishikesh Donadkar <r-donadkar@xxxxxx>
> [snip]