Inbound PCI and Memory Corruption

[Benjamin Herrenschmidt]

On Fri, 2013-06-21 at 10:14 -0700, Peter LaDow wrote:
> After a (finally!) successful search of the list archive, I did find
> this:
> 
> http://web.archiveorange.com/archive/v/9IQA26gPvdf4foaTcmCV
> 
> Which seems very related to my problem.  However, the patch that is
> ultimately referenced is in place in 3.0.80 (see
> https://lists.ozlabs.org/pipermail/linuxppc-dev/2006-February/021267.html).
> 
> Hmmm...  perhaps our FDT is bad?

Afaik e300 is slightly out of order, maybe it's missing a memory barrier
somewhere.... One thing to try is to add some to the dma_map/unmap ops.

Also audit the driver to ensure that it properly uses barriers when
populating descriptors (and maybe compare to a more recent version of
the driver upstream).

Ben.