Re: PCI DMA to small buffers on cache-incoherent arch

Tom Rini
2002-06-10T19:15:18Z

On Mon, Jun 10, 2002 at 12:03:19PM -0700, Roland Dreier wrote:
> >>>>> "Tom" == Tom Rini <trini@kernel.crashing.org> writes:
>
> Tom> No. We should just make it come out to a nop for arches that
> Tom> don't need it. Otherwise we'll end up with ugly things like:
> Tom> #ifdef CONFIG_NOT_CACHE_COHERENT ... #else ... #endif
> Tom> All over things like USB...
>
> Good point. How about the following: add a file to each arch named
> say, <asm/dma_buffer.h>, that defines a macro __dma_buffer. This
> macro would be used as follows to mark DMA buffers (example taken from
> <linux/usb.h>):
[snip]
> Comments?

SMP_CACHE_BYTES is non-sensical on 4xx (and 8xx) since they don't do
SMP..

--
Tom Rini (TR1265)