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Date: Wed, 9 Jul 2008 20:44:35 -0400
From: Josh Boyer <jwboyer@linux.vnet.ibm.com>
To: benh@kernel.crashing.org
Subject: Re: [PATCH] powerpc: Fix problems with 32bit PPC's running with
	more than 2GB of RAM
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Cc: linuxppc-dev@ozlabs.org, Stefan Roese <sr@denx.de>
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On Thu, 10 Jul 2008 06:39:39 +1000
Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:

> On Wed, 2008-07-09 at 16:22 -0400, Josh Boyer wrote:
> > On Thu, 10 Jul 2008 06:02:38 +1000
> > Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
> > 
> > > On Wed, 2008-07-09 at 15:44 +0200, Stefan Roese wrote:
> > > > This patch enables 32bit PPC's (with 36bit physical address space, e.g.
> > > > IBM/AMCC PPC44x) to run with more than 2GB of RAM. Mostly its just
> > > > replacing types (unsigned long -> phys_addr_t).
> > > > 
> > > > Tested on an AMCC Katmai with 4GB of DDR2.
> > > > 
> > > > Signed-off-by: Stefan Roese <sr@denx.de>
> > > 
> > > But DMAs will break no ?
> > 
> > How?
> 
> Hrm... forget it. It's fine up to 4G of RAM... (ie. as long as DMA is
> below 32 bits).

Right.  We haven't really dealt with anything larger than 4 GiB, and we
certainly aren't dealing with discontiguous DRAM due to I/O ranges.

josh