Is there a binding for IORESOURCE_DMA population?

[Shawn Guo]

On Sat, Jul 16, 2011 at 02:16:40PM -0500, Rob Herring wrote:
> On 07/16/2011 09:40 AM, Shawn Guo wrote:
> > On Sat, Jul 16, 2011 at 08:55:41PM +0800, Tabi Timur-B04825 wrote:
> >> Arnd Bergmann wrote:
> >>> Right, this is what I had in mind. I think this is reasonable.
> >>> If you need so many channels, the device tree will be huge already,
> >>> so this doesn't add that much bloat either.
> >>
> >> I'm not sure I agree.  It seems that specifying nodes for each DMA channel 
> >> (virtual or physical) is meaningless because the only property in the node 
> >> is the "reg", which is really just a cell-index in disguise.
> >>
> > Yes, that's exactly why I do not appreciate the solution.
> > 
> >> My vote is to have a node only for the DMA engine, and let the DMA handle 
> >> the virtual and physical channels internally.
> >>
> > It's not about virtual or physical channel.  I'm asking suggestion on
> > how we bind the channel number for each dma client device in device
> > tree and how they will get the number from device tree when they get
> > probed.
> > 
> 
> In this case, it is the event (or request line) that is important not
> the channel assignment.

Exactly.

> This is how the hardware is wired up and the
> main variation between chips with SDMA. Since DT describes the h/w, this
> needs to be described.
> 
We absolutely need to describe the events.  The topic here is how.

-- 
Regards,
Shawn