From owner-freebsd-arm@FreeBSD.ORG Fri Jan 3 19:48:48 2014 Return-Path: Delivered-To: freebsd-arm@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 0A909DF5; Fri, 3 Jan 2014 19:48:48 +0000 (UTC) Received: from smtpauth3.wiscmail.wisc.edu (wmauth3.doit.wisc.edu [144.92.197.226]) (using TLSv1 with cipher RC4-MD5 (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id C9CB61DCC; Fri, 3 Jan 2014 19:48:47 +0000 (UTC) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; CHARSET=US-ASCII Received: from avs-daemon.smtpauth3.wiscmail.wisc.edu by smtpauth3.wiscmail.wisc.edu (Oracle Communications Messaging Server 7u4-27.01(7.0.4.27.0) 64bit (built Aug 30 2012)) id <0MYU00A00CCX5A00@smtpauth3.wiscmail.wisc.edu>; Fri, 03 Jan 2014 13:48:46 -0600 (CST) X-Spam-PmxInfo: Server=avs-3, Version=6.0.3.2322014, Antispam-Engine: 2.7.2.2107409, Antispam-Data: 2014.1.3.193914, SenderIP=0.0.0.0 X-Spam-Report: AuthenticatedSender=yes, SenderIP=0.0.0.0 Received: from wanderer.tachypleus.net (pool-72-66-107-173.washdc.fios.verizon.net [72.66.107.173]) by smtpauth3.wiscmail.wisc.edu (Oracle Communications Messaging Server 7u4-27.01(7.0.4.27.0) 64bit (built Aug 30 2012)) with ESMTPSA id <0MYU008BVCD8S300@smtpauth3.wiscmail.wisc.edu>; Fri, 03 Jan 2014 13:48:45 -0600 (CST) Message-id: <52C7141C.2040801@freebsd.org> Date: Fri, 03 Jan 2014 14:48:44 -0500 From: Nathan Whitehorn User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 To: Ian Lepore Subject: Re: FreeBSD 10 on Dockstar (Marvell Kirkwood) References: <20131231211054.GA90299@moore.morphism.de> <1388770603.1158.273.camel@revolution.hippie.lan> <20140103175914.GC98342@moore.morphism.de> <52C70B9B.9090205@freebsd.org> <1388778165.1158.302.camel@revolution.hippie.lan> In-reply-to: <1388778165.1158.302.camel@revolution.hippie.lan> X-Enigmail-Version: 1.6 Cc: freebsd-arm@FreeBSD.org, Markus Pfeiffer X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 03 Jan 2014 19:48:48 -0000 On 01/03/14 14:42, Ian Lepore wrote: > On Fri, 2014-01-03 at 14:12 -0500, Nathan Whitehorn wrote: >> On 01/03/14 12:59, Markus Pfeiffer wrote: >>> Hi Ian, >>> >>> On Fri, Jan 03, 2014 at 10:36:43AM -0700, Ian Lepore wrote: >>>> On Tue, 2013-12-31 at 21:10 +0000, Markus Pfeiffer wrote: >>>>> Hi all, >>>>> >>>>> I managed "fixing" it by editing the dockstar.dts file and putting for ranges: >>>>> >>>>> ranges = <0x0 0x2f 0xf9300000 0x00100000> >>>>> >>>>> Now I just have to figure out why this "fixes" it, and what damage that patch >>>>> does. >>>>> I also have some pathces for the LED on the dockstar which will tip up in my >>>>> github soon. >>>>> >>>>> Cheers, >>>>> markus >>>> After looking at the marvell code and docs, and some info I found about >>>> the dockstar at OpenWRT.org, I think the attached patch is the right fix >>>> for a dockstar (it maps the nand flash, and removes mappings for NOR >>>> flash and an LED; the dockstar doesn't seem to have NOR flash, and the >>>> LED thing seems to be out of place). >>>> >>> Can I find information anywhere as to what this ranges command actually means? >>> I was assuming it has something to do with memory mappings, but I didn't find >>> any info as to what in particular the 0x2f _means_. >>> >>> >> The ranges field, as per IEEE 1275 (page 175), provides a mapping from >> addresses in a child address space to the parent. It is a set of tuples >> of (child base address, parent base address, size), with the field >> widths being (#address-cells on this node [2], #address-cells of parent >> bus [1], #size-cells on this node [1]). This mapping table is used for >> resource allocation of children, to map bus-local requests for addresses >> to addresses on the parent bus (in this case, physical memory >> addresses). In this case, the following: >> >> ranges = <0x0 0x2f 0xf9300000 0x00100000> >> >> means that addresses 0x2f-0x0010002f in "localbus" should map linearly to physical addresses 0xf9300000-0xf9310000. This is used for drivers on the attached sub-bus so that their resources (in the "reg" properties, or in "ranges" if there are further sub-buses) can be specified in bus-local address units. The kernel code probably misinterprets it badly if changing this affects anything, which in turn implies that our kernel code is horribly bug-riddled. >> >> Note also that this replacement is not equivalent to the old mappings, since it shifts all the mappings downward by 0x20 bytes. >> -Nathan > So now we're back to the usual question... do we adhere to published or > defacto standards? The defacto standards for arm dts files are > basically "whatever linux does is right by definition" (::sigh::), and > what we've got in the marvell dts files right now is basically similar > to what linux uses (I think linux has evolved a bit since our dts files > were created; they were probably compatible at some point). > > Here's what linux is doing these days. I notice they've moved the > mapping info from "mrvl,lbc" to "marvell,kirkwood-mbus", "simple-bus"; > > https://github.com/torvalds/linux/blob/master/arch/arm/boot/dts/kirkwood.dtsi > > -- Ian > > > I don't see any particular way in which these files violate the standards. Did I miss something? In this case, so long as a 1:1 linear mapping can be made, it's perfectly alright for "child bus addresses" to be basically arbitrary codes, as here. IEEE 1275 PCI does this, for example, with 96-bit "child address" ranges that are a combination of the bus, slot, and function for the card along with actual 64-bit memory locations. In general, Linux's device tree support seems to be much more standards-compliant than ours. It's FreeBSD that seems to take the more fragile and ad-hoc approach, which is what usually creates this "I have to go patch my DTS now" problem. -Nathan