MPC860 reorder and invalidate dcache

Joakim Tjernlund Joakim.Tjernlund at
Mon Aug 19 08:04:52 EST 2002

> > ... The other mapping is used for flash commands and to write data to flash.
> > Each time I read I do a invalidate_dcache_range() to pick up updates made from
> > the uncached mapping.
> Why don't you do a single invalidate after the write to cover the region
> you just updated?

You read my mind :-). I tried this once before but failed, but that was problably due to
some stupid mistake. Now I am ready to give it another try.

Just to make sure, I only need to invalidate the address space that actually modify
the flash contents?
> > I was just hoping that the 'sync' instruction was an "accident", but now I know
> > better.
> Those of us that have programmed PowerPC all of these years seldom include
> a 'sync' instruction by accident.  We are more likely to not use them and
> then discover later they are necessary :-)

Amen :-)
But I still think it is a bit strange that you need a sync when you invalidate since all
you want to do is throw away the data in the cache, but what do I know :-)


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