Subject: Re: how to allocate physically contiguous memory?
To: Andrew Gallatin <gallatin@cs.duke.edu>
From: Fred L. Templin <templin@nas.nasa.gov>
List: port-alpha
Date: 05/07/1997 17:19:38
Drew,

If you find out, please let me know because I'm currently in a similar
situation (porting a driver; would be nice to be able to allocate phys.
contiguous buffers). However, I have written a DMA mapping facility which
will create a "scatter/gather" vector given a kernel virtual address and
byte count. The scatter/gather vector gives the physical addresses and
lengths of all physically dis-contiguous segments of the buffer, and
most hardware is smart enough to do scatter/gather (i.e. accept a list
of segments which comprise the larger buffer) if you map the segments
onto the hardware properly. Let me know if something like this would be
helpful to you...

Regards,

Fred
templin@nas.nasa.gov