From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751389AbZHJG2W (ORCPT ); Mon, 10 Aug 2009 02:28:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750952AbZHJG2W (ORCPT ); Mon, 10 Aug 2009 02:28:22 -0400 Received: from qw-out-2122.google.com ([74.125.92.25]:25171 "EHLO qw-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750823AbZHJG2V (ORCPT ); Mon, 10 Aug 2009 02:28:21 -0400 MIME-Version: 1.0 Date: Mon, 10 Aug 2009 16:28:22 +1000 Message-ID: <1d3f23370908092328l6e980f3ft2d5a8f8f37c26fcf@mail.gmail.com> Subject: Rethinking MicroBlaze commandline precedence From: John Williams To: Michal Simek , John Linn , David DeBonis Cc: microblaze-uclinux@itee.uq.edu.au, Linux Kernel list Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Currently, MicroBlaze commandline handling in order of lowest to highest priority, looks like this: 1. pointer in r5 from bootloader 2. CONFIG_CMDLINE=... 3. "chosen" section in DTS/DT 4. CONFIG_CMDLINE=... && CONFIG_CMDLINE_FORCE I'm wondering if a cmdline in r5 should override the DTS. My thinking is based on two observations: (a) not everyone will use a bootloader like u-boot that can manipulate DTBs easily before kernel boot (b) a custom cmdline string in r5 allows the latest possible binding (runtime), where as the DTB is typically created at compile time. So, how about this order instead: 1. CONFIG_CMDLINE=... 2. "chosen" section in DTS/DT 3. pointer in r5 from bootloader 4. CONFIG_CMDLINE=... and CONFIG_CMDLINE_FORCE Then, apart from CMDLINE_FORCE, the precedence goes from earliest binding (kernel build) to latest (runtime via bootloader/r5). Thoughts? John -- John Williams, PhD, B.Eng, B.IT PetaLogix - Linux Solutions for a Reconfigurable World w: www.petalogix.com p: +61-7-30090663 f: +61-7-30090663