From owner-freebsd-ppc@FreeBSD.ORG Fri Oct 27 14:32:50 2006 Return-Path: X-Original-To: freebsd-ppc@freebsd.org Delivered-To: freebsd-ppc@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8D1A416A415; Fri, 27 Oct 2006 14:32:50 +0000 (UTC) (envelope-from raj@semihalf.com) Received: from mail.semihalf.com (mail.semihalf.com [62.233.211.107]) by mx1.FreeBSD.org (Postfix) with ESMTP id E8AAD43D5D; Fri, 27 Oct 2006 14:32:49 +0000 (GMT) (envelope-from raj@semihalf.com) Received: from localhost (localhost [127.0.0.1]) by mail.semihalf.com (Postfix) with ESMTP id 3BFA7143C5; Fri, 27 Oct 2006 16:32:47 +0200 (CEST) Received: from mail.semihalf.com ([127.0.0.1]) by localhost (mail.semihalf.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 28531-08; Fri, 27 Oct 2006 16:32:45 +0200 (CEST) Message-ID: <4542188D.6010600@semihalf.com> Date: Fri, 27 Oct 2006 16:32:45 +0200 From: Rafal Jaworowski MIME-Version: 1.0 To: Peter Grehan Content-Type: text/plain; charset=ISO-8859-2; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: by amavisd-new at semihalf.com Cc: freebsd-ppc@freebsd.org Subject: PowerPC architecture directory layout X-BeenThere: freebsd-ppc@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Porting FreeBSD to the PowerPC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 27 Oct 2006 14:32:50 -0000 Hi Peter, we're in the process of porting FreeBSD 6.1 to the Freescale MPC85555 embedded PowerPC platform. This is PowerQUICC3 integrated telecom controller based on the e500 (Book E compliant) core, which is different in some important aspects from the "traditional" PowerPC family (AIM). We'd like to get our port integrated into the FreeBSD source tree eventually to mark the start of bringing embedded PowerPC support to the project. There are some general issues we identified and we'd like to discuss: Current FreeBSD/powerpc port is deeply entangled with OF and Mac dependencies: when adding support for a new architecture variant one is faced with sys/powerpc/powerpc which is the low-level stuff, quite often strictly OF/Mac-oriented. What would be the strategy for adding a new sub-arch within PowerPC as in current shape it's not very extensible and prepared for such addition? Our initial thoughts and approach was splitting out the existing low-level code into the following hierarchy: sys/powerpc/powerpc - files common to all PowerPC variants sys/powerpc/aim - specific to "traditional" PowerPC specs (most of present sys/powerpc/powerpc) sys/powerpc/{e500, others} - specific to e500 or other specs to be supported The problem with current PowerPC port however is OF dependencies, so to have really clean separation for potential further platforms support the current port should be also split into strict AIM part (which would be used by all AIM ports) and strict OF part. What is your view and recommended route to follow? Can we work together on redisigning the sys/powerpc layout to make it more extensible when new platforms are added etc.? I believe FreeBSD/ARM folks must have had similar considerations exercise as they have a number of different variations within ARM family, maybe we can learn from them somehow? kind regards, Rafal