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Re: LOADADDR and low physical addresses?

To: Jun Sun <>
Subject: Re: LOADADDR and low physical addresses?
From: "Maciej W. Rozycki" <>
Date: Mon, 9 Sep 2002 20:17:53 +0200 (MET DST)
Cc: Matthew Dharm <>, Linux-MIPS <>
In-reply-to: <>
Organization: Technical University of Gdansk
Original-recipient: rfc822;
On Fri, 6 Sep 2002, Jun Sun wrote:

> > And this is where I think the add_memory_region() magic might need to
> > happen.  Do I need to add the on-chip SRAM and control registers using
> > add_memory_region()?  
> I don't think you have to.  I *think* it works if you don't.  Not sure
> know if you actuall do add.

 Well, you have to register usable RAM areas with add_memory_region(), if
you want to make them available to Linux.  Adding other ranges is optional
but you have to consider a part of the kernel may want to know if the
range is usable or occupied (consider e.g. the PCI setup code modifying
BARs).  It's also nice and sometimes useful to a user to let him see what
space is occupied.

 What you register with add_memory_region() is printed upon boot and
available from /proc/iomem.

+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+        e-mail:, PGP key available        +

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