Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932991AbbDNQg1 (ORCPT ); Tue, 14 Apr 2015 12:36:27 -0400 Received: from foss.arm.com ([217.140.101.70]:34419 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932248AbbDNQgS (ORCPT ); Tue, 14 Apr 2015 12:36:18 -0400 Date: Tue, 14 Apr 2015 17:36:13 +0100 From: Mark Rutland To: Catalin Marinas Cc: Kumar Gala , "linux-arm-msm@vger.kernel.org" , "devicetree@vger.kernel.org" , "abhimany@codeaurora.org" , Will Deacon , "linux-kernel@vger.kernel.org" , "arm@kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [RFC PATCH 0/5] Add smp booting support for Qualcomm ARMv8 SoCs Message-ID: <20150414163613.GM28709@leverpostej> References: <1428601031-5366-1-git-send-email-galak@codeaurora.org> <20150410100529.GA6854@e104818-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150410100529.GA6854@e104818-lin.cambridge.arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1908 Lines: 42 On Fri, Apr 10, 2015 at 11:05:29AM +0100, Catalin Marinas wrote: > On Thu, Apr 09, 2015 at 12:37:06PM -0500, Kumar Gala wrote: > > This patch set adds support for SMP boot on the MSM8x16 family of Qualcomm SoCs. > > > > To support SMP on the MSM8x16 SoCs we need to add ARMv8/64-bit SCM interfaces to > > setup the boot/release addresses for the secondary CPUs. In addition we need > > a uniquie set of cpu ops. I'm aware the desired methods for booting secondary > > CPUs is either via spintable or PSCI. However, these SoCs are shipping with a > > firmware that does not support those methods. > > And the reason is? Some guesses: > > a) QC doesn't think boot interface (and cpuidle) standardisation is > worth the effort (to put it nicely) > b) The hardware was available before we even mentioned PSCI > c) PSCI is not suitable for the QC's SCM interface > d) Any combination of the above > > I strongly suspect it's point (a). Should we expect future QC hardware > to do the same? > > You could argue the reason was (b), though we've been discussing PSCI > for at least two years and, according to QC press releases, MSM8916 > started sampling in 2014. > > The only valid reason is (c) and if that's the case, I would expect a > proposal for a new firmware interface protocol (it could be PSCI-based), > well documented, that can be shared with others that may encounter the > same shortcomings. There's no need to even fork PSCI. The PSCI specification will evolve over time as vendors request changes and we try to accomodate them. If there's something that PSCI doesn't do that you need it to, contact ARM. Other vendors already have. Mark. -- 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/