From owner-freebsd-hackers Sat Mar 10 11:11:37 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from prism.flugsvamp.com (cb58709-a.mdsn1.wi.home.com [24.17.241.9]) by hub.freebsd.org (Postfix) with ESMTP id 3B7C037B718 for ; Sat, 10 Mar 2001 11:11:35 -0800 (PST) (envelope-from jlemon@flugsvamp.com) Received: (from jlemon@localhost) by prism.flugsvamp.com (8.11.0/8.11.0) id f2AJ8wr76450; Sat, 10 Mar 2001 13:08:58 -0600 (CST) (envelope-from jlemon) Date: Sat, 10 Mar 2001 13:08:58 -0600 (CST) From: Jonathan Lemon Message-Id: <200103101908.f2AJ8wr76450@prism.flugsvamp.com> To: romain@kzsu.stanford.edu, hackers@freebsd.org Subject: Re: if_fxp - the real point X-Newsgroups: local.mail.freebsd-hackers In-Reply-To: Organization: Cc: Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In article you write: >As a newcomer to this, I'm a little confused. There's a slew >of datasheets at Intel's web site > http://www.intel.com/design/network/datashts/index.htm >that don't seem to require NDA. (Just this week, I used the >82559 docs to implement a polled version of if_fxp). > >If the components in question are not there, can anyone identify them? Datasheets != manuals. The datasheet simply tells you "this is the overall purpose of this feature". "This is a high level view of selected registers". What it doesn't tell you is how to put everything together, nor does it provide critical information such as the layout of the datastructures needed. Take a concrete example, the datasheet for the 82558: http://www.intel.com/design/network/datashts/297360.htm S 4.1.2.7 describes how the chip DMAs data to/from host memory. What is the layout of the control block for the transfer? S 4.2 talks about the EEPROM interface. How do you determine the size of the attached EEPROM, which is needed in order to know how many address bits to shift in? S 4.3.2 mentions PHY flow control; PHY based and flow based. How do you select between these two? Where do you set up the flow control parameters? You can't find the answers to any of these in the datasheets. The datasheets may provide a tiny bit of information, and hint at how things actually operate, but there is not sufficient information to develop a driver from them. -- Jonathan To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message