Re: [PATCH] spi/pxa2xx-pci: Enable DMA binding through device name

[Andy Shevchenko <andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>]

On Fri, 2014-07-25 at 12:19 +0200, Arnd Bergmann wrote:
> On Friday 25 July 2014 12:55:59 Mika Westerberg wrote:
> > On Fri, Jul 25, 2014 at 12:07:14PM +0300, Mika Westerberg wrote:
> > > On Fri, Jul 25, 2014 at 10:38:36AM +0200, Arnd Bergmann wrote:
> > > > On Friday 25 July 2014 11:22:49 Mika Westerberg wrote:

[]

> > Something like this?

Arnd, this dependency to certain DMA driver looks really bad.

If we go that way, can we split that part to [another] module and make
it dependent to DW_DMAC?

Or shall we introduce a dmaengine type field in the platform data and
dynamically choose proper filter-whatever-function to get the channel?

> > Hock Leong / Chiaue Ee, are you able to check if this works on your BYT
> > machines?

> What I think you got wrong here (by following my bad advice) is the master
> number. Looking at the code for dw_dma, I think src_master needs to be '1'
> for your driver.

On some SoCs we have up to 4 masters. It's blurry for me how the SPI
should choose those masters. Currently it works fine, but I suspect
there are [might be] performance issues.

What about AVR32 case? We have to fix drivers as well there.

> the dw_dma driver can be simplified a little by removing the special
> case for the request line setting.

Yes, this part I like.

-- 
Andy Shevchenko <andriy.shevchenko-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Intel Finland Oy

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