[Linux-ia64] Re: 64 Bits DMA Addresses for Alloc Consistent Interfaces.

David Mosberger
2003-05-15T15:06:04Z

>>>>> On Thu, 15 May 2003 08:17:58 -0500, Colin Ngam <cngam@sgi.com> said:

Colin> Anyway, to make a long story short, we like to "extend" these
Colin> interfaces to return DMA addresses of 64 bits if and when the
Colin> driver has the full capabality to support DAC - via it's DMA
Colin> mask capability setting.

Colin> This extention will not break current usages of these
Colin> interface, and as driver changes, this extension will enable
Colin> platforms to support all of it's Physical Memory via the
Colin> above 2 Interfaces without exhausting limited system mapping
Colin> resources.

James and I have been discussing this very point for the last week or
so. My preferred solution is to add an explicit dma-mask argument to
coherent/non-coherent allocators, but James prefers to do this via a
new GFP flag (GFP_DMA32 or some such).

--david