Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756516Ab3C1QG4 (ORCPT ); Thu, 28 Mar 2013 12:06:56 -0400 Received: from mail-qe0-f54.google.com ([209.85.128.54]:56629 "EHLO mail-qe0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756188Ab3C1QGz (ORCPT ); Thu, 28 Mar 2013 12:06:55 -0400 Date: Thu, 28 Mar 2013 12:06:52 -0400 (EDT) From: Nicolas Pitre To: Will Deacon cc: Rob Herring , Stefano Stabellini , "xen-devel@lists.xensource.com" , "linux@arm.linux.org.uk" , "arnd@arndb.de" , Marc Zyngier , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v3] [RFC] arm: use PSCI if available In-Reply-To: <20130328160026.GA3026@mudshark.cambridge.arm.com> Message-ID: References: <1364388639-11210-1-git-send-email-stefano.stabellini@eu.citrix.com> <20130327133811.GE18429@mudshark.cambridge.arm.com> <20130327172306.GB20990@mudshark.cambridge.arm.com> <51545BE4.9050206@gmail.com> <20130328160026.GA3026@mudshark.cambridge.arm.com> User-Agent: Alpine 2.03 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1736 Lines: 44 On Thu, 28 Mar 2013, Will Deacon wrote: > On Thu, Mar 28, 2013 at 03:39:42PM +0000, Nicolas Pitre wrote: > > On Thu, 28 Mar 2013, Rob Herring wrote: > > > > > On 03/28/2013 09:51 AM, Nicolas Pitre wrote: > > > > On Thu, 28 Mar 2013, Stefano Stabellini wrote: > > > > > > > >> - the interface to bring up secondary cpus is different and based on > > > >> PSCI, in fact Xen is going to add a PSCI node to the device tree so that > > > >> Dom0 can use it. > > > >> > > > >> Oh wait, Dom0 is not going to use the PSCI interface even if the node is > > > >> present on device tree because it's going to prefer the platform smp_ops > > > >> instead. > > > > > > > > Waitaminute... I must have missed this part. > > > > > > > > Who said platform specific methods must be used in preference to PSCI? > > > > > > I did. Specifically, I said the platform should be allowed to provide > > > its own smp_ops. A platform may need to do addtional things on top of > > > PSCI for example. > > > > Then the platform should have its special hook that would override the > > default PSCI methods. But, by *default* the PSCI methods should be used > > if the related DT information is present. > > I'm fine with a default PSCI-based implementation, providing that it's actually > a layer between the smp ops and the psci code, not just glueing pointers > together. Absolutely. Even in the MCPM case, the PSCI is wrapped into a MCPM backend while MCPM provides its own SMP ops methods. Nicolas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/