----- Original Message -----
From: "Maciej W. Rozycki" <email@example.com>
To: "Jun Sun" <firstname.lastname@example.org>
Cc: <email@example.com>; <firstname.lastname@example.org>
Sent: Tuesday, December 18, 2001 8:50 PM
Subject: Re: ISA
> On Tue, 18 Dec 2001, Jun Sun wrote:
> > Now when people using ioremap/readb/writeb method to access ISA memory
> > which lives in the lower range of the "bus memory space", it will
> > system ram under 1:1 mapping assumption.
> Hmm, I believe there should be no such problem. For systems equipped
> with the PCI bus we may just assume the low 16MB of PCI memory address
> space is reserved for ISA memory addresses (it's hardwired for many
> platforms, so there should be no problem with it), i.e. avoid programming
> BARs to point to that space and make ioremap() (or __ioremap(), actually)
> act accordingly, i.e. assume a 1:1 mapping for addresses above 16MB and
> perform an ISA mapping for ones below 16MB.
That sounds like the simplest and best solution.