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

[Rishikesh Donadkar <r-donadkar@ti.com>]

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@ti.com>
>>>
>>> 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@ti.com>
>>> Co-developed-by: Pratyush Yadav <p.yadav@ti.com>
>>> Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
>>> Signed-off-by: Jai Luthra <j-luthra@ti.com>
>>> Co-developed-by: Rishikesh Donadkar <r-donadkar@ti.com>
>>> Signed-off-by: Rishikesh Donadkar <r-donadkar@ti.com>
> [snip]