At 10:45 AM 10/27/99 , Jason Thorpe wrote:
>On Wed, 27 Oct 1999 09:17:31 -0700 (PDT) 
>  eeh@one-o.com (Eduardo E. Horvath) wrote:
>
>  > > I guess most PCI bus-master devices assume the host is little endian,
>  > > so bswap*() functions are needed on passing non-bytestream data via DMA.
>  > > (i.e. on accessing variables allocated by bus_dmamem_alloc(9) and
>  > >  bus_dmamem_map(9))
>  > 
>  > Once again this should be handled by bus_space(9) macros.  We may need
>  > to add some new ones specifically for the host to access DMA memory,
>  > if it's only being mapped in once and used statically as an area for
>  > host/device communication.  
>
>Since it's obviously not "bus space", random memory being DMA'd to a
>device can't be handled with bus_space(9).

But it can be handled by bus_dma(9).  Specifically, bus_dma_sync can
do any required endian conversions.
-- 
Matt Thomas               Internet:   matt@3am-software.com
3am Software Foundry      WWW URL:    http://www.3am-software.com/bio/matt/
Cupertino, CA             Disclaimer: I avow all knowledge of this message