From owner-freebsd-hackers Mon May 29 12:15:26 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from anchor-post-33.mail.demon.net (anchor-post-33.mail.demon.net [194.217.242.91]) by hub.freebsd.org (Postfix) with ESMTP id A268637B87F; Mon, 29 May 2000 12:15:19 -0700 (PDT) (envelope-from dfr@nlsystems.com) Received: from nlsys.demon.co.uk ([158.152.125.33] helo=herring.nlsystems.com) by anchor-post-33.mail.demon.net with esmtp (Exim 2.12 #1) id 12wV0H-000Byk-0X; Mon, 29 May 2000 20:15:10 +0100 Received: from salmon.nlsystems.com (salmon.nlsystems.com [10.0.0.3]) by herring.nlsystems.com (8.9.3/8.8.8) with ESMTP id UAA33495; Mon, 29 May 2000 20:15:56 +0100 (BST) (envelope-from dfr@nlsystems.com) Date: Mon, 29 May 2000 20:20:31 +0100 (BST) From: Doug Rabson To: Dennis Cc: Mike Smith , Jeroen Ruigrok van der Werven , John Hay , hackers@freebsd.org Subject: Re: 4.0 - Isa devices not being probed In-Reply-To: <200005291700.NAA23834@etinc.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Mon, 29 May 2000, Dennis wrote: > At 06:36 PM 5/27/00 -0700, Mike Smith wrote: > >> Existing bus abstractions tend to let think that the same software driver > >> can deal with different buses, bridges or IO methods without having to > >> care about how these things actually behave, notably regarding buffering > >> and ordering rules. This is untrue. > > > >A good bus abstraction lets you care as much or as little as necessary. > >The NetBSD framework (which we use) allows you to do this. > > The best "portable" coding method is with memory-mapped registers, which > seems to have been omitted from this "implementation", which is the gripe > here. Perhaps "portable" within the OS was your goal, but in the mean time > "portable" between very different OSs has been tainted. After an OS > specific initialization, the driver can be completely OS independent (as > are our LINUX and FreeBSD drivers) using memory-mapped registers. Using normal C pointers to memory-mapped registers is not portable. -- Doug Rabson Mail: dfr@nlsystems.com Nonlinear Systems Ltd. Phone: +44 20 8442 9037 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message