From owner-freebsd-arm@FreeBSD.ORG Sat Sep 14 15:43:33 2013 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 ESMTP id 53ABA4FF; Sat, 14 Sep 2013 15:43:33 +0000 (UTC) (envelope-from ian@FreeBSD.org) Received: from mho-01-ewr.mailhop.org (mho-03-ewr.mailhop.org [204.13.248.66]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 008BB2CC5; Sat, 14 Sep 2013 15:43:29 +0000 (UTC) Received: from c-24-8-230-52.hsd1.co.comcast.net ([24.8.230.52] helo=damnhippie.dyndns.org) by mho-01-ewr.mailhop.org with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.72) (envelope-from ) id 1VKs0O-000BuH-LE; Sat, 14 Sep 2013 15:43:28 +0000 Received: from [172.22.42.240] (revolution.hippie.lan [172.22.42.240]) by damnhippie.dyndns.org (8.14.3/8.14.3) with ESMTP id r8EFhPfO010734; Sat, 14 Sep 2013 09:43:25 -0600 (MDT) (envelope-from ian@FreeBSD.org) X-Mail-Handler: Dyn Standard SMTP by Dyn X-Originating-IP: 24.8.230.52 X-Report-Abuse-To: abuse@dyndns.com (see http://www.dyndns.com/services/sendlabs/outbound_abuse.html for abuse reporting information) X-MHO-User: U2FsdGVkX1+MaafYJZuieIDvKxh91f/m Subject: Re: Patch for Cross-Reference Phandles From: Ian Lepore To: Nathan Whitehorn In-Reply-To: <52346D71.4080407@freebsd.org> References: <522CC7E0.9060508@freebsd.org> <5231D8A6.9080501@freebsd.org> <20130914133155.GA32845@alchemy.franken.de> <52346D71.4080407@freebsd.org> Content-Type: text/plain; charset="us-ascii" Date: Sat, 14 Sep 2013 09:43:25 -0600 Message-ID: <1379173405.1197.7.camel@revolution.hippie.lan> Mime-Version: 1.0 X-Mailer: Evolution 2.32.1 FreeBSD GNOME Team Port Content-Transfer-Encoding: 7bit Cc: freebsd-arm@FreeBSD.org, freebsd-ppc@FreeBSD.org, freebsd-sparc64 X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Porting FreeBSD to the StrongARM Processor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 14 Sep 2013 15:43:33 -0000 On Sat, 2013-09-14 at 09:06 -0500, Nathan Whitehorn wrote: > On 09/14/13 08:31, Marius Strobl wrote: > > On Thu, Sep 12, 2013 at 10:07:18AM -0500, Nathan Whitehorn wrote: > >> On 09/08/13 13:54, Nathan Whitehorn wrote: > >>> Open Firmware has three namespaces for handles: > >>> 1. Instance handles, for open devices > >>> 2. Package handles for the client interface > >>> 3. Package handles for device tree cross references > >>> > >>> On Powermac hardware, we assume that (2) and (3) are identical and > >>> call both phandles. On embedded FDT systems, you can't open devices > >>> and so we abuse ihandle_t for (3). IBM pSeries hardware, however, has > >>> all three things. With that in mind, I'd like to start separating > >>> them. The patch at > >>> http://people.freebsd.org/~nwhitehorn/xref_phandle.diff adds a new > >>> function (OF_child_xref_phandle) that takes a phandle of type (3) and > >>> turns into one of type (2) by searching for entries named "phandle", > >>> "ibm,phandle", or "linux,phandle" in the tree. This should work for > >>> FDT as well, but is not connected in the patch to anything actually > >>> FDT related. > >>> > >>> Comments would be appreciated. I'd like to get to get this as in as > >>> soon as possible (given the HEAD freeze) otherwise. > >>> -Nathan > >> Since I haven't heard anything, it shouldn't affect any existing > >> platforms or code, and it would be nice to have this interface available > >> in the 10.x series, I plan to ask re@ for commit approval tomorrow. > >> Please let me know if there are any objections. > > Technically that patch is fine. It would be nice if you could fix the > > style bugs before committing, though. In OF_child_xref_phandle(), the > > variables should go above the comment and you don't need to initialize > > the static global one in ofw_pcibus.c to zero explicitly. If you do > > nevertheless, spaces should go before and after the '='. > > > > Thanks! I think the explicit zero initialization adds some clarity for > people reading the code, so I'd like to keep it. The rest of the changes > have been made. > -Nathan The explicit zero init also makes it 4 bytes harder to fit the kernel into a small flash on embedded systems. We should be eliminating zero-inits that move items from bss to data, not adding new ones. -- Ian