From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from fed1rmmtao05.cox.net (fed1rmmtao05.cox.net [68.230.241.34]) by ozlabs.org (Postfix) with ESMTP id 8177E67FE5 for ; Wed, 10 Aug 2005 02:21:35 +1000 (EST) Date: Tue, 9 Aug 2005 09:21:33 -0700 From: Tom Rini To: Kumar Gala Message-ID: <20050809162133.GL3187@smtp.west.cox.net> References: <200508091647.32925.arnd@arndb.de> <80BD2461-35F1-4B9D-983E-E2BCFFC08C77@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <80BD2461-35F1-4B9D-983E-E2BCFFC08C77@freescale.com> Cc: linuxppc64-dev@ozlabs.org, Geert Uytterhoeven , Arnd Bergmann , Linux/PPC Development Subject: Re: Merging ppc32 and ppc64 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Aug 09, 2005 at 10:01:05AM -0500, Kumar Gala wrote: > >I think you are both right, just using different terminology. The > >running kernel uses its own representation of the device tree, which > >is neither the flattened stuff nor using the OF interfaces. The > >conversion from OF to the flattened tree is done by the kernel itself. > > > > Apple OF \ > > SLOF \ > > pSeries |-1- prom_init------, > > PIBS / \ > > ... / \ > > \ > > other -----------------------------2-- > >unflatten_device_tree--3-- > > boot loader / > > / > > iSeries ----------- early_setup---` > > > >All "regular" machines enter in the traditional prom_init path (1) > >from Open Firmware. The embedded machines that are too memory > >constraint > >to use SLOF have a flattened device tree in their boot loader and the > >legacy iSeries boxes can fake the device tree in their > >iSeries_early_setup > >function. The main entry point (2) is entered by all machines when the > >flattened device tree is there and the kernel builds its tree > >representation > >for run time (3). > > I guess my point is that in the "new" powerpc arch doing steps 1 & 3 > should no longer be part of the kernel proper. The should be handled > by boot wrappers of some form. I know Ben tool care to ensure that > prom_init was isolated from kernel proper and I'm suggesting we move > it into a boot wrapper going forward. That's not 100% true because as Segher said, prom_init.c is part of the kernel (tree, image), but is what does the translation. -- Tom Rini http://gate.crashing.org/~trini/