USB mass storage and ARM cache coherency

Andy Green andy at
Mon Feb 8 05:03:14 EST 2010

On 02/08/10 10:51, Somebody in the thread at some point said:

> We could of course flush the caches every time we get a page fault but
> that's far from optimal, especially since DMA-capable drivers to do not
> pollute the D-cache and don't need this extra flushing. Note that the
> recent ARM processors have PIPT caches but separate for I and D and it's
> the PIO drivers that pollute the D-cache.

Just noting that AFAIK iMX31 USB and MMC drivers both are PIO at the 
moment, for lack of any platform DMA support of its unusual DMA engine.


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