API change for bus_dma

Tue Jul 1 02:30:32 PDT 2003

On Mon, Jun 30, 2003 at 10:03:46AM -0400, Andrew Gallatin wrote:
> The idea is that I want to establish a mapping that can be used many
> times without any driver or kernel attention.  I don't want to do
> anything in terms of a system call, or interrupt, etc, to sync the
> cache with the state of the DMA'ed page before a DMA read or after a DMA
> write.
> 
> For example, scatter gather mapping on alphas (if FreeBSD supported it
> for PCI devices) would be fine with me since its cache-coherent and
> doesn't require any ddi_dma_sync() operations.

What makes you shure about alpha dma to be cache-coherent?
I'm not shure that the current implementation of _bus_dmamap_sync()
without barriers is correct.

-- 
B.Walter                   BWCT                http://www.bwct.de
ticso at bwct.de                                  info at bwct.de