busdma_machdep.c with more than 512M memory

[M. Warner Losh]

In message: <AANLkTikOKU8KOaw6aFd1dMqpcZW+cMkU72mrDBcUncVq at mail.gmail.com>
            Neel Natu <neelnatu at gmail.com> writes:
: This assumes that pmap_mapdev() always returns an uncached mapping
: which is true for n64 kernels but not for o32 kernels with memory
: beyond 512MB.
: 
: Any objections if I commit the following patch that makes
: pmap_mapdev() always return an uncached mapping.

Is there ever a time on MIPS you'd want to make a device you are
talking to cached?

I'd say it is a vanishingly rare event, if ever.  If we come up with
one, we, at that time, should implement a way to do that mapping.

I have no objections to this patch, but I've not gone over it with a
fine tooth comb.

Warner