From: "Bradley D. LaRonde" <brad@ltc.com>
To: "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>, "Jun Sun" <jsun@mvista.com>
Cc: <jim@jtan.com>, <linux-mips@oss.sgi.com>
Subject: Re: ISA
Date: Tue, 18 Dec 2001 21:05:01 -0500 [thread overview]
Message-ID: <056a01c18831$919daf90$5601010a@prefect> (raw)
In-Reply-To: Pine.GSO.3.96.1011219023325.16267B-100000@delta.ds2.pg.gda.pl
----- Original Message -----
From: "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>
To: "Jun Sun" <jsun@mvista.com>
Cc: <jim@jtan.com>; <linux-mips@oss.sgi.com>
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
space,
> > which lives in the lower range of the "bus memory space", it will
collide with
> > 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.
Regards,
Brad
WARNING: multiple messages have this Message-ID (diff)
From: "Bradley D. LaRonde" <brad@ltc.com>
To: "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>, Jun Sun <jsun@mvista.com>
Cc: jim@jtan.com, linux-mips@oss.sgi.com
Subject: Re: ISA
Date: Tue, 18 Dec 2001 21:05:01 -0500 [thread overview]
Message-ID: <056a01c18831$919daf90$5601010a@prefect> (raw)
Message-ID: <20011219020501.FTcLKyT1gmQ0NMl8xe14L0EtJ3EJTgpCUCLe6fHXZ30@z> (raw)
In-Reply-To: Pine.GSO.3.96.1011219023325.16267B-100000@delta.ds2.pg.gda.pl
----- Original Message -----
From: "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>
To: "Jun Sun" <jsun@mvista.com>
Cc: <jim@jtan.com>; <linux-mips@oss.sgi.com>
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
space,
> > which lives in the lower range of the "bus memory space", it will
collide with
> > 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.
Regards,
Brad
next prev parent reply other threads:[~2001-12-19 3:04 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-12-18 20:04 ISA Jim Paris
2001-12-18 20:27 ` ISA Bradley D. LaRonde
2001-12-18 20:27 ` ISA Bradley D. LaRonde
2001-12-18 21:44 ` ISA Jim Paris
2001-12-18 22:01 ` ISA Maciej W. Rozycki
2001-12-18 22:24 ` ISA Jim Paris
2001-12-19 1:17 ` ISA Jun Sun
2001-12-19 1:50 ` ISA Maciej W. Rozycki
2001-12-19 2:05 ` Bradley D. LaRonde [this message]
2001-12-19 2:05 ` ISA Bradley D. LaRonde
2001-12-19 2:09 ` ISA Jun Sun
2001-12-19 2:30 ` ISA Maciej W. Rozycki
2001-12-19 9:52 ` ISA Geert Uytterhoeven
2001-12-19 13:59 ` ISA Alan Cox
2001-12-19 13:59 ` ISA Alan Cox
2001-12-19 14:06 ` ISA Geert Uytterhoeven
2001-12-20 13:09 ` ISA Maciej W. Rozycki
2001-12-20 13:14 ` ISA Geert Uytterhoeven
2001-12-20 13:39 ` ISA Maciej W. Rozycki
2001-12-20 13:45 ` ISA Geert Uytterhoeven
2001-12-20 14:06 ` ISA Maciej W. Rozycki
2001-12-21 16:12 ` ISA Alan Cox
2001-12-21 16:12 ` ISA Alan Cox
2001-12-21 18:44 ` ISA Jim Paris
2002-01-01 19:22 ` ISA Jun Sun
2002-01-01 19:34 ` ISA Bradley D. LaRonde
2002-01-02 1:03 ` ISA M. Warner Losh
2002-01-02 9:41 ` ISA Geert Uytterhoeven
2002-01-02 14:36 ` ISA Bradley D. LaRonde
2002-01-01 20:13 ` ISA Alan Cox
2002-01-01 20:13 ` ISA Alan Cox
2001-12-19 1:28 ` ISA Maciej W. Rozycki
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