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From: Arnd Bergmann <arnd@arndb.de>
To: Matt Porter <mporter@ti.com>
Subject: Re: [PATCH v6 03/10] ARM: edma: add AM33XX support to the private EDMA API
Date: Thu, 31 Jan 2013 20:58:39 +0000
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On Thursday 31 January 2013, Matt Porter wrote:
> On Wed, Jan 30, 2013 at 09:32:58AM +0000, Arnd Bergmann wrote:
> > On Wednesday 30 January 2013, Matt Porter wrote:
> > > +               dma_cap_set(DMA_SLAVE, edma_filter_info.dma_cap);
> > > +               of_dma_controller_register(dev->of_node,
> > > +                                          of_dma_simple_xlate,
> > > +                                          &edma_filter_info);
> > > +       }
> > 
> > How do you actually deal with the problem mentioned by Padma, that
> > the filter function does not know which edma instance it is looking
> > at? If you assume that there can only be a single edma instance in
> > the system, that is probably a limitation that should be documented
> > somewhere, and ideally the probe() function should check for that.
> 
> I make an assumption of one edma instance in the system in the case of
> DT being populated. This is always true right now as the only SoC with
> two EDMA controllers in existence is Davinci DA850. Until recently,
> Davinci had no DT support. Given the steady work being done today on DT
> support for DA850, it'll probably be something needed in 3.10.
> 
> I will add a comment and check in probe() to capture this assumption
> and then plan to update separately to support DA850 booting from DT.

Ok, sounds good. Hopefully by then we will already have a nicer
way to write an xlate function that does not rely on a filter
function.

	Arnd