Re: bus_dmamap_sync() for USB

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Tue, Jun 24, 2008 at 04:33:47PM -0400, Michael Lorenz wrote:
> >I guess some of it is because the descriptors are mapped uncached  
> >on the
> >mips. This includes some parts that are never accessed by hardware.
> >This could be improved by splitting memory allocation in 2 parts
> >(one for descriptors used by hardware, and one for the host-only part
> >of the descriptors).
> 
> They would be mapped uncached on sparc64 as well, wouldn't they? The  
> U60 should have much more bandwidth between RAM and CPU but somehow I  
> doubt the impact would be that big.

I'm not sure. reading sources, BUS_DMAMAP_COHERENT disables the vcache for
the mapping, but I'm not sure this is the CPU cache. sparc64 also has a
BUS_DMA_NOCACHE which makes different things.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--