[PATCH 1/4] Add DMA sector to Documentation/powerpc/booting-without-of.txt file.

[Segher Boessenkool]

>>> +    - extended : Set the DMA channel to work at extended
>> chain mode.
>>> +                 If not set, the DMA channel will work at basic
>>> +                 chain mode.
>>
>> Call it "extended-chain-mode", perhaps?
>
> Is it maybe too long?

Not really no.  It's only 19 characters, and it isn't used
all over the place, so that should be fine.

>>> +    - reserved : Reserve the DMA channel to device.
>>
>> What does this do?  Reserve it for what device, and where?
>> The OS driver?
>>
>
> Yes, it reserve for the special device, which must use the fixed
> channel. Thus, reserve channels requested by that device.
>
> And in the device node of dts file, you can use such as
> "dma-channel=<&dma-ch0>" to reference the below channel:
>
> dma-ch0: ch0 at 100 {
> ...
> }

Right, so you don't need a "reserved" property, that information
is in the tree already.

Alternatively, for ease of use, you could put a "reserved" bitmap
in the master DMA controller node.  I wouldn't make nodes per
channel anyway, just describe the channels using properties -- that
takes care of the "reg" vs. "ranges" thing too, etc.


Segher