Re: [PATCH 01/18] dmaengine: of-dma: Add support for optional router configuration callback

Peter Ujfalusi
2020-10-29T02:38:55Z

Hi Vinod,

On 28/10/2020 7.55, Vinod Koul wrote:

>> To summarize:
>> In of_dma_route_allocate() the router does not yet know the channel we
>> are going to get.
>> In of_dma_xlate() the DMA driver does not yet know if the channel will
>> use router or not.
>> I need to tell the router the event number it has to send, which is
>> based on the channel number I got.
>
> Sounds reasonable, btw why not pass this information in xlate. Router
> will have a different xlate rather than non router right, or is it same.

Yes, the router's have their separate xlate, but in that xlate we do not
yet have a channel. I don't know what is the event I need to send from
the router to trigger the channel.

> If this information is anyway available in DT might be better to get it
> and use from DT

Without a channel number I can not do anything.
It is close to a chicken and egg problem.

- Péter