Subject: Re: how to allocate physically contiguous memory?
To: Andrew Gallatin <>
From: Fred L. Templin <>
List: port-alpha
Date: 05/07/1997 17:19:38

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...