[PATCH 3/3] [POWERPC] Add docs for Freescale DMA & DMA channel device tree nodes

[Timur Tabi]

Kumar Gala wrote:

>> Shouldn't we put some text somewhere that we're calling it the Elo 
>> controller even though that word isn't used in the reference manual?
> 
> we don't really have a place to put that.  its effectively documented 
> right here.

I still think we need something.  Otherwise, people are going to be confused. 
  I know I would.  I'd be searching the RM for the string "ELO" and wonder why 
it wasn't there.


>>> +  Example:
>>> +    dma at 21000 {
>>
>> Shouldn't this be dma at 21300?
> 
> its an example that has not basis is reality :)

Eh?

>> The DMA controller and the DMA channels need a "device-id", so that 
>> they can be identified by number.  Some peripherals, like the SSI, can 
>> only use the controller and channel number.  This is what I have in my 
>> 8610 DTS:
> 
> Why not use reg for this?  I don't see any reason to add another "unique 
> id" when there is already one.

There isn't one.  Why should the driver assume that reg/80 == channel #? 
Besides, I still can't differentiate between DMA controller 0 and DMA 
controller 1 that way.  No, we need a device-id.

-- 
Timur Tabi
Linux Kernel Developer @ Freescale