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Re: ISA

To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: ISA
From: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Date: Wed, 19 Dec 2001 15:06:32 +0100 (MET)
Cc: "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>, Jun Sun <jsun@mvista.com>, jim@jtan.com, Linux/MIPS Development <linux-mips@oss.sgi.com>
In-reply-to: <E16GhG0-0002zb-00@the-village.bc.nu>
Sender: owner-linux-mips@oss.sgi.com
On Wed, 19 Dec 2001, Alan Cox wrote:
> > You must _not_ use readb()/writeb() and friends with ISA memory space!
> > You must use isa_readb()/isa_writeb() and friends!
> 
> Linus is saying the reverse. Drivers are moving away from isa_
> 
> > But for memory accesses, ISA memory space is not necessarily at `address 0'.
> 
> ioremap uses ookies, its up to yoyu what you hide in the cookie from an ISA
> ioremap

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)?

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

Gr{oetje,eeting}s,

                                                Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                                            -- Linus Torvalds


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