From owner-freebsd-hackers@FreeBSD.ORG Tue Feb 15 21:03:28 2005 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2931916A4CE for ; Tue, 15 Feb 2005 21:03:28 +0000 (GMT) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.FreeBSD.org (Postfix) with ESMTP id 6CCAE43D2D for ; Tue, 15 Feb 2005 21:03:27 +0000 (GMT) (envelope-from scottl@samsco.org) Received: from [192.168.254.19] (ibook-nai.samsco.home [192.168.254.19]) (authenticated bits=0) by pooker.samsco.org (8.13.1/8.13.1) with ESMTP id j1FL3U02036080; Tue, 15 Feb 2005 14:03:31 -0700 (MST) (envelope-from scottl@samsco.org) Message-ID: <42126390.5020804@samsco.org> Date: Tue, 15 Feb 2005 14:03:12 -0700 From: Scott Long User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.7.5) Gecko/20041217 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Andrew Gallatin References: <16914.22016.593790.719399@grasshopper.cs.duke.edu> In-Reply-To: <16914.22016.593790.719399@grasshopper.cs.duke.edu> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-2.8 required=3.8 tests=ALL_TRUSTED autolearn=failed version=3.0.2 X-Spam-Checker-Version: SpamAssassin 3.0.2 (2004-11-16) on pooker.samsco.org cc: freebsd-hackers@freebsd.org Subject: Re: mapping small parts of a pci card to conserve KVA X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 15 Feb 2005 21:03:28 -0000 Andrew Gallatin wrote: > I maintain drivers for a PCI card which presents itself as having > 16MB of address space. Eg: > > mx0: mem 0xf9000000-0xf9ffffff irq 20 at device 3.0 on pci1 > > However, most of that address space does not need to be mapped into > the host. Really, only a little over 2MB needs to be mapped (3 regions > with length 1024 bytes, 256 bytes, and 2MB). > > I've tried to re-write things so that I make multiple calls > to bus_alloc_resource() with the (hopefully) appropriate offset and > lengths. Eg: > > rid = PCIR_MAPS; > *res = bus_alloc_resource(is->arch.dev, SYS_RES_MEMORY, &rid, > (u_long)offset, > (u_long)(offset + len - 1), len, > RF_ACTIVE|PCI_RF_DENSE); > > At least on 5.3R, I seem to get back the same struct resource * from > each call. rman_get_virtual() returns a different kva for each > mapping, yet they all seem to map to the same physical address. > Eg, I call vtophys() on the results of rman_get_virtual(), > for each segment, and they all map to 0xf9000000. > > Is there a way to just map what I need? > > Thanks, > > Drew > You can use pmap_mapdev() to create a KVA mapping of an arbitrary physaddr+len. In fact, this is exactly what newbus uses to create the PCI MEMIO resources when bus_alloc_resource() is called. I'm not sure if the range is mapped and activated before the driver makes that call, Warner or John might know for sure. Scott