[U-Boot] [PATCH] mpc83xx: Make it boot again

[Joakim Tjernlund]

>
> Timur Tabi wrote:
> > Wood Scott-B07421 wrote:
> > > To be totally safe, we probably want to do a readback plus twi (to turn
> > > a data dependency into a flow dependency) before the isync.
> >
> > twi == trap word immediate?
>
> Yes.
>
> > If so, I don't see how that will turn a data dependency into a flow dependency.
> > Is that some sort of side effect of twi?
>
> It decides based on the input register (data dependency) whether to cause a trap (flow dependency).  We never want it to actually trap, so we set a condition that says never trap, but the dependency is still there -- the hardware doesn't decode it as a no-op.
>
> See arch/powerpc/include/asm/io.h, it's used in the I/O read accessors.

Guys, unless you will do the twi stuff now I suggest you ACK this
patch so 83xx works again.