Accessing flash directly from User Space [SOLVED]

[Joakim Tjernlund]

>
> > On Friday 30 October 2009 16:08:55 Alessandro Rubini wrote:
> > > > asm("eieio; sync");
> > >
> > > Hmm...
> > >    : : : "memory"
> > >
> > > And, doesn't ";" start a comment in assembly? (no, not on powerpc
> > it seems)
> >
> > Yes, I think the barrier is wrong.
> > Please try with
> >
> > #define mb()   __asm__ __volatile__("eieio\n sync\n" : : :
> > "memory")
>
> That definition worked great.  I must have missed the : : : "memory" bit when
> I was digging through code.
>
> Thanks, that gives me about a 2x speedup over the msync() calls.

Exactly when should you use the barrier? At every access,
every read or when changing from write to read?

 Jocke