From owner-freebsd-arch  Thu Jan 11  7:20:21 2001
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From: Terry Lambert <tlambert@primenet.com>
Message-Id: <200101111518.IAA15411@usr08.primenet.com>
Subject: Re: cvs commit: src/sys/gnu/i386/isa dgb.c dgm.c dgmreg.h dgreg.h
To: peter@netplex.com.au (Peter Wemm)
Date: Thu, 11 Jan 2001 15:18:32 +0000 (GMT)
Cc: msmith@FreeBSD.ORG (Mike Smith),
	jlemon@flugsvamp.com (Jonathan Lemon),
	peter.jeremy@alcatel.com.au (Peter Jeremy),
	babkin@FreeBSD.ORG (Sergey Babkin), freebsd-arch@FreeBSD.ORG
In-Reply-To: <200101110323.f0B3N4Q64114@mobile.wemm.org> from "Peter Wemm" at Jan 10, 2001 07:23:04 PM
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> > > ie:
> > >   if (IS_PCI(board_type)) {
> > > 	value = *mem[reg];
> > >   } else {
> > >         if (board->window != window(reg))
> > > 	   board->window = window(reg);
> > > 	value = inb(base + (reg % winsize));
> > >   }
> > 
> > Typically, if you have half a clue, you will separate the ISA-aware parts 
> > of the driver from the PCI-aware parts and use a set of function vectors. 
> > Makes for much cleaner code. 8)
> 
> Yes, that is what Peter Jeremy said in the original email..  It can be
> done but doesn't come for free.  I was merely responding to the suggestion
> to use the bus_space_ macros with a reason why they cannot be used in this
> scenario to hide the different access methods.  Yes, bus_space can be used
> in the backend functions, but not at the top level driver.

Surely, this is a problem which has to be solved similarly
for multiple cards with similar function.

Rather than being a one-off, the abstraction should at _least_
have a recommended form, if not a documented DKI mechanism.


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.


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