[uClinux-dev] Caches and DMA

David McCullough davidm at snapgear.com
Fri Apr 19 00:16:37 EDT 2002


Jivin Fabrice Gautier lays it down ...
> Hi,
> 
> Can someone tell me if the kernel expect DMA memory to be not cacheable? ie:
> does the kernel sync the caches after a DMA transfert or does it expect this
> memory not be cacheable/cached in the first place ? 

I think it depends on your PCI implementation (HW).  I was working on a
SuperH a while back and I needed to flush/invalidate the areas I was using
for DMA to get sane behaviour.  It was hooked in somewhere quite cleanly, I
can dig it up if you like,

Cheers,
Davidm

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