Re: [PATCH] ARM: DTS: am33xx: Use the new DT bindings for the eDMA3

[Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>]

On Tuesday 08 December 2015 12:22:09 Peter Ujfalusi wrote:
> On 12/08/2015 11:51 AM, Arnd Bergmann wrote:
> > On Tuesday 08 December 2015 09:42:26 Peter Ujfalusi wrote:
> >> On 12/04/2015 11:51 PM, Tony Lindgren wrote:
> >>>>
> >>>> Please just drop the /bits/ 16 and use normal cells.
> >>>
> >>> Yeah agreed, makes things less confusing for sure 
> >>
> >> 4.4 will be the first kernel where we will have the new eDMA bindings. I have
> >> chosen to use 16bit array for specifying the channels used for memcpy
> >> (ti,edma-memcpy-channels) and for the reserving paRAM slots
> >> (ti,edma-reserved-slot-ranges). As of now we have maximum of 64 channels and
> >> 512 paRAM slots. 16bit is more than enough to store this information and it
> >> even gives us enough room if ever in the future these numbers are going to
> >> increase (which  they are not).
> >>
> >> But in order to change them to 32bit the driver needs to be changed as well.
> >> Currently we do not have drivers (in 4.4) using the new bindings, 4.4 is not
> >> yet out, so it might be possible to change the binding document and the driver
> >> to use 32bit arrays. The driver internally uses 16bit type for these which I'm
> >> not going to change, but the code parsing the DT needs to be adjusted for the
> >> new data type.
> >>
> >> If Vinod is willing to take update for the DT binding of eDMA for 4.4-rc, I
> >> can cook up the patch(es) to do so.
> > 
> > I hadn't realized that it was already in 4.4-rc. The change should be trivial
> > enough though, so I'd still do it. If Vinod would rather not change it now,
> > it's not overly important though.
> 
> But this change must be done before we have actual users of these properties,
> which is the am33xx, am437x and the da850 conversion series I have sent recently.
> We might want to have this changed for 4.4 since it is going to be an LTS
> release...

Yes, that's what I meant: We either get the patch into 4.4 by creating a
branch for Vinod to pull with this change, and base all other changes in your
4.5 series on the same branch, or we don't change it at all.

	Arnd
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