Date: Mon, 29 May 2000 20:20:31 +0100 (BST) From: Doug Rabson <dfr@nlsystems.com> To: Dennis <dennis@etinc.com> Cc: Mike Smith <msmith@freebsd.org>, Jeroen Ruigrok van der Werven <jruigrok@via-net-works.nl>, John Hay <jhay@mikom.csir.co.za>, hackers@freebsd.org Subject: Re: 4.0 - Isa devices not being probed Message-ID: <Pine.BSF.4.21.0005292019410.2947-100000@salmon.nlsystems.com> In-Reply-To: <200005291700.NAA23834@etinc.com>
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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
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