Subject: Re: PCI-audio & endianness (eso.c/mulaw.c)
To: Eduardo E. Horvath <>
From: Jason Thorpe <>
List: tech-kern
Date: 10/27/1999 10:45:54
On Wed, 27 Oct 1999 09:17:31 -0700 (PDT) (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).

        -- Jason R. Thorpe <>