From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Schwebel Subject: Re: Representing Embedded Architectures at the Kernel Summit Date: Tue, 2 Jun 2009 23:40:05 +0200 Message-ID: <20090602214005.GL32630@pengutronix.de> References: <1243956140.4229.25.camel@mulgrave.int.hansenpartnership.com> <20090602211057.GA10800@flint.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Return-path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:57424 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752824AbZFBVkH (ORCPT ); Tue, 2 Jun 2009 17:40:07 -0400 Content-Disposition: inline In-Reply-To: <20090602211057.GA10800@flint.arm.linux.org.uk> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Grant Likely , James Bottomley , ksummit-2009-discuss@lists.linux-foundation.org, linux-arch@vger.kernel.org, linux-e On Tue, Jun 02, 2009 at 10:10:58PM +0100, Russell King wrote: > I really don't think combining SoC support is going to be realistic, > device tree or not. When we had just four machine types (RiscPC, > EBSA110, EBSA285, Netwinder) I did look into this and came to the > conclusion that it would be far too inefficient for there to be any > win. > > The big problem we have is that the only commonality between different > SoCs is that the CPU executes ARM instructions. Everything else is > entirely up to the SoC designer - eg location of memory, spacing of > memory banks, type of interrupt controller, etc is all highly SoC > specific. Nothing outside of the ARM CPU itself is standardized. And even with the cpu core, we usually build kernels with optimized toolchains for their cpu family. But nevertheless - describing hardware inside a mach* makes sense. rsc -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:57424 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752824AbZFBVkH (ORCPT ); Tue, 2 Jun 2009 17:40:07 -0400 Date: Tue, 2 Jun 2009 23:40:05 +0200 From: Robert Schwebel Subject: Re: Representing Embedded Architectures at the Kernel Summit Message-ID: <20090602214005.GL32630@pengutronix.de> References: <1243956140.4229.25.camel@mulgrave.int.hansenpartnership.com> <20090602211057.GA10800@flint.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20090602211057.GA10800@flint.arm.linux.org.uk> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Grant Likely , James Bottomley , ksummit-2009-discuss@lists.linux-foundation.org, linux-arch@vger.kernel.org, linux-embedded@vger.kernel.org, Josh Boyer , Tim Bird Message-ID: <20090602214005.egXoderhCM9rNVA4ntRVnDJnHYiinjcs0Ru_fDPsWic@z> On Tue, Jun 02, 2009 at 10:10:58PM +0100, Russell King wrote: > I really don't think combining SoC support is going to be realistic, > device tree or not. When we had just four machine types (RiscPC, > EBSA110, EBSA285, Netwinder) I did look into this and came to the > conclusion that it would be far too inefficient for there to be any > win. > > The big problem we have is that the only commonality between different > SoCs is that the CPU executes ARM instructions. Everything else is > entirely up to the SoC designer - eg location of memory, spacing of > memory banks, type of interrupt controller, etc is all highly SoC > specific. Nothing outside of the ARM CPU itself is standardized. And even with the cpu core, we usually build kernels with optimized toolchains for their cpu family. But nevertheless - describing hardware inside a mach* makes sense. rsc -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |