From owner-freebsd-hackers@FreeBSD.ORG Tue Jul 14 14:08:54 2009 Return-Path: <owner-freebsd-hackers@FreeBSD.ORG> Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 7C7CF106566C for <freebsd-hackers@freebsd.org>; Tue, 14 Jul 2009 14:08:54 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id 4EC938FC20 for <freebsd-hackers@freebsd.org>; Tue, 14 Jul 2009 14:08:54 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from bigwig.baldwin.cx (66.111.2.69.static.nyinternet.net [66.111.2.69]) by cyrus.watson.org (Postfix) with ESMTPSA id CB0DB46B5C; Tue, 14 Jul 2009 10:08:53 -0400 (EDT) Received: from jhbbsd.hudson-trading.com (unknown [209.249.190.8]) by bigwig.baldwin.cx (Postfix) with ESMTPA id CEE568A098; Tue, 14 Jul 2009 10:08:52 -0400 (EDT) From: John Baldwin <jhb@freebsd.org> To: Norbert Koch <nkoch@demig.de> Date: Tue, 14 Jul 2009 08:49:51 -0400 User-Agent: KMail/1.9.7 References: <4A5B3F1B.3040207@demig.de> <200907131435.30452.jhb@freebsd.org> <4A5C2EF8.3080208@demig.de> In-Reply-To: <4A5C2EF8.3080208@demig.de> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Message-Id: <200907140849.51702.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0.1 (bigwig.baldwin.cx); Tue, 14 Jul 2009 10:08:52 -0400 (EDT) X-Virus-Scanned: clamav-milter 0.95.1 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-2.5 required=4.2 tests=AWL,BAYES_00,RDNS_NONE autolearn=no version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on bigwig.baldwin.cx Cc: freebsd-hackers@freebsd.org Subject: Re: bus device driver X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD <freebsd-hackers.freebsd.org> List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, <mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers> List-Post: <mailto:freebsd-hackers@freebsd.org> List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help> List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, <mailto:freebsd-hackers-request@freebsd.org?subject=subscribe> X-List-Received-Date: Tue, 14 Jul 2009 14:08:54 -0000 On Tuesday 14 July 2009 3:08:40 am Norbert Koch wrote: >=20 > John Baldwin schrieb: > > On Monday 13 July 2009 10:05:15 am Norbert Koch wrote: > > =20 > >> Hello. > >> > >> I just started to write a device > >> driver for a multi-function pci card. > >> This card replaces a number of > >> independant isa hardware devices. > >> This pci card contains memory, i/o > >> and interrupt sources. > >> I want my device driver to > >> serve as a bus driver between > >> the pci driver and the specific > >> device drivers. > >> > >> Do I need more than the following (see below)? > >> Do I have to do any bookkeeping for allocated resources? > >> =20 > > > > How do the child devices receive resources? Do they suballocate region= s=20 from=20 > > BARs in the PCI device or is your device a subtractive bridge that will= =20 > > forward requests for ISA ranges and your devices all use ISA ranges? > > > > =20 > I am not quite sure that I understand what you mean. What is the differen= ce? > My old device drivers were isa based. We had all our resources in the=20 > 15-16M isa hole. > So I want to change them to just allocate resources from the pci bus=20 > through the bus device driver. > I thought it would be sufficient to just forward *_alloc_resource calls=20 > directly to the pci driver. > Clearly, my drivers will have to know that they are just forwarded=20 > through to pci > and have to know what sub-resources to allocate. =46rom a hardware perspective, how do your devices know which addresses to= =20 decode? Do they consume subranges of BARs or are they assigned fixed=20 addresses somehow? Do they have programmable decoders of some sort=20 themselves? If you wish to have the PCI bus assign you resources then that= =20 implies that your PCI device has a BAR and that you want to request resourc= es=20 for that BAR and then hand out subranges of that to your children. If that= =20 is the case, then you will need to allocate the resources for the BAR for t= he=20 PCI device from the PCI bus. Then your bus driver for the PCI device will= =20 need to suballoc from that BAR to your children devices. =2D-=20 John Baldwin