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To: Geert Uytterhoeven <>
Subject: Re: ISA
From: "Maciej W. Rozycki" <>
Date: Thu, 20 Dec 2001 14:09:03 +0100 (MET)
Cc: Alan Cox <>, Jun Sun <>,, Linux/MIPS Development <>
In-reply-to: <>
Organization: Technical University of Gdansk
On Wed, 19 Dec 2001, Geert Uytterhoeven wrote:

> OK, so I can check for < 16 MB in ioremap(), and readb() and friends will
> handle it fine. You're not supposed to call ioremap() for real RAM anyway, so
> there's no ambiguity.
> But what about request_mem_region() and friends? How can I distinguish between
> ISA memory and the first 16 MB of RAM (or ROM, or whatever my board has 
> there)?

 Well, as I stated in another mail (but in another thread, I think) you
may try request_mem_region(virt_to_phys(ioremap(...))), especially as you
really want to reserve an area in the CPU's physical address space and not
in the bus's one.

> Or am I not supposed to let those things show up in /proc/iomem?

 I think the appearance is not the point here.  The point is to prevent a
driver from accessing an already occupied area. 

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

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