Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754128AbbDNTtS (ORCPT ); Tue, 14 Apr 2015 15:49:18 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:60278 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752972AbbDNTtH convert rfc822-to-8bit (ORCPT ); Tue, 14 Apr 2015 15:49:07 -0400 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2098\)) Subject: Re: [RFC PATCH 0/5] Add smp booting support for Qualcomm ARMv8 SoCs From: Kumar Gala In-Reply-To: <20150414163613.GM28709@leverpostej> Date: Tue, 14 Apr 2015 14:49:04 -0500 Cc: Catalin Marinas , "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" Content-Transfer-Encoding: 8BIT Message-Id: <07185B2C-3F37-4E70-9096-1EF5EA8D68CE@codeaurora.org> References: <1428601031-5366-1-git-send-email-galak@codeaurora.org> <20150410100529.GA6854@e104818-lin.cambridge.arm.com> <20150414163613.GM28709@leverpostej> To: Mark Rutland X-Mailer: Apple Mail (2.2098) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2439 Lines: 55 > On Apr 14, 2015, at 11:36 AM, Mark Rutland wrote: > > 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. But what is someone to do between the period of getting PSCI spec updated and needing to ship a product with firmware? The take still sounds like if you don’t implement an exact version of PSCI you are screwed from being supported in the upstream ARM64 kernel. - k -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project -- 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/