-----Original Message-----
From: David Laight [mailto:David.Laight@ACULAB.COM]
Sent: Tuesday, March 05, 2013 1:16 AM
To: Jia Hongtao-B38951; linuxppc-dev@lists.ozlabs.org;
galak@kernel.crashing.org
Cc: Wood Scott-B07421
Subject: RE: [PATCH V4] powerpc/85xx: Add machine check handler to fix
PCIe erratum on mpc85xx
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quoted

A PCIe erratum of mpc85xx may causes a core hang when a link of PCIe
goes down. when the link goes down, Non-posted transactions issued via
the ATMU requiring completion result in an instruction stall.
At the same time a machine-check exception is generated to the core to
allow further processing by the handler. We implements the handler
which skips the instruction caused the stall.

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Just skipping the instruction doesn't seem a good idea.
But I suspect that re-initialising the PCI interface is also almost
impossible.

This *skipping* is the best way I thought for this errata.
It's not perfect but works.

-Hongtao.

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Does the mpc83xx have the same errata?
We've seen machine-check faults using the CSB bridge on an 83xx doing a
'pio' access after a PEX_DMA transfer to certain target addresses stalls
- software gives up waiting for the dma.
The target is an fpga, nothing is mapped at those addesses - but we'd
expect to get ~0u back as happens on other slave windows.
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I also remember some problems with single word DMA.
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	David
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