[U-Boot-Users] [PATCH][RFC] lib_ppc: make the flush_cache stronger
Dave Liu
r63238 at freescale.com
Fri Apr 25 12:28:04 CEST 2008
> > Current flush_cache code does
> >
> > 1. clean the dcache with dcbst, but not invalidate dcache
> > 2. invalidate icache
> >
> > This patch use the dcbf instead of dcbst to have stronger
> > semantic, clean the dcache and invalidate dcache.
>
> On which processors did you test the changes? I have some unclear
> memories of dcbf having problems on for example MPC8xx ?
on 83xx parts.
I remember the 601 processor not support the dcbf.
> > We have two options:
> >
> > 1. Separate functions for them like linux kernel.
> > A. clean dcache (dcbst) for DMA_TO_DEVICE
> > B. invalidate dcache (dcbi) for DMA_FROM_DEVICE
> > C. flush dcache (dcbf) for DMA_BIDIRECTIONAL.
> > 2. Make current flush_cache stronger semanctic.
> > use the dcbf instead of dcbst.
> >
> > Which one is better? or you have better option?
> > Please suggest.
>
> We discussed this a bit on IRC; Kumar suggested to go for 1., and I
> agree.
Where is the IRC? Could you point it to me?
Thanks,
Dave
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