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From: Segher Boessenkool <segher@kernel.crashing.org>
Subject: Re: [Cbe-oss-dev] [PATCH] Implement check_legacy_ioport() on PS3
Date: Fri, 30 Mar 2007 15:44:02 +0200
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Olof Johansson <olof@lixom.net>, linuxppc-dev@ozlabs.org,
	David Woodhouse <dwmw2@infradead.org>, cbe-oss-dev@ozlabs.org
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> I was thinking that we could have one single helper shared by most
> platforms who allow that legacy ISA crap which checks the device-tree
> for known ISA devices. That would cover PREP, CHRP and pSeries at
> least...

Make the helper check every device node under the ISA
node and translate the "reg" in there.  If the requested
legacy I/O region is a subset of the union of all those,
allow the access, otherwise not.  This should cover all
cases (well at least those with a valid device tree, heh).


Segher