Re: [PATCH/RFC] dmaengine: add a slave parameter to__dma_request_channel()

From: Russell King - ARM Linux
Date: Fri Mar 30 2012 - 06:44:07 EST

On Fri, Mar 30, 2012 at 12:40:12PM +0200, Guennadi Liakhovetski wrote:
> On Fri, 30 Mar 2012, Russell King - ARM Linux wrote:
> > On Fri, Mar 16, 2012 at 03:28:39PM +0100, Guennadi Liakhovetski wrote:
> > > Yessss!!! Let's do that! :-D Now, you're proposing exactly the same, as
> > > what I was proposing! :-) Now you just have to remove the filter function
> > > parameter from dma_request_channel() - it is anyway the same for all and
> > > implemented in the dmaengine core - and you get
> > >
> > > dma_request_channel(mask, slave_desc)
> > >
> > > which is exactly what I was proposing! :-)
> >
> > Bollocks it is. You're wanting to use the peripheral address, width
> > and burst size to try to determine what channel to use. That's a
> > totally crackpot idea, and as I've already said several times it won't
> > work in many real life cases we have already.
> I'm afraid I'm just somehow failing to explain my thoughts to you,
> Russell. I don't think I ever said about using addresses, widths etc.

Not directly - what you said was about combining the request functionality
along with the slave_config functionality. The slave_config functionality
takes exactly what I said above: the addresses, widths, burst size of the

Therefore, you did _by implication of what the functions you have been
referring to do_ been talking exactly about using addresses, widths and
burst sizes to select the channel.
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