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

Vinod Koul
2020-11-09T11:45:40Z

Hey Peter,

On 28-10-20, 11:56, Peter Ujfalusi wrote:
> 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.

We get 'channel' in xlate, so wont that help? I think I am still missing
something here :(

--
~Vinod