[PATCH 4/4] POWERPC: Merge 32 and 64-bit dma code

[Benjamin Herrenschmidt]

> Yeah, the statement this time should be why do you keep _single :)
> It don't really mind which one we keep, but having both and both
> optional seems rather odd.

It would be more logic to implement _single on top of _page.. as long as
we can still do sub-page mappings (needed on ppc64) which I think we can
using the offset / size args of _page...

But that means more work changing the existing ppc64 backends :-) So
probably a worthwhile long term goal but what Becky did is ok for the
transition. I can look at fixing up the ppc64 ones to implement page
(and see if that causes any problem) some time after Plumbers conf.

Cheers,
Ben.