[PATCH] ARM:SAMSUNG: Move S3C DMA driver to drivers/dma

[Jassi Brar]

On Tue, Jun 7, 2011 at 1:45 PM, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:
> On Tue, Jun 07, 2011 at 01:39:43PM +0530, Jassi Brar wrote:
>> Unfortunately, no. There are some features of Samsung's DMA API that
>> the drivers have come to rely upon.
>> Besides, I am not particularly a fan of the generic API. And IIRC,
>> neither is Ben Dooks, the designer of the
>> Samsung's DMA API.
>
> We are now at the point where this is non-optional.  If the generic API
> doesn't fit what Samsung needs, then that needs to be discussed and
> whatever problems there are need to be resolved.
The discussion did take off a few months ago, but we didn't reach anywhere.
Being able to queue request from the 'done' callback, the need of
circular buffer
API (possibly a free-running one too) and callbacks in irq-context, as
they happen,
were a few requirements for having fast peripherals with shallow fifo
work without underruns.