Re: [U-Boot-Users] [PATCH][RFC] lib_ppc: make the flush_cache stronger

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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.

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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