From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753874AbbIROPd (ORCPT ); Fri, 18 Sep 2015 10:15:33 -0400 Received: from mail.kernel.org ([198.145.29.136]:50995 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752031AbbIROPc (ORCPT ); Fri, 18 Sep 2015 10:15:32 -0400 Date: Fri, 18 Sep 2015 22:15:24 +0800 From: Shawn Guo To: Shenwei Wang Cc: "jason@lakedaemon.net" , Huang Anson , "linux-kernel@vger.kernel.org" , "kernel@pengutronix.de" , Sudeep Holla , "tglx@linutronix.de" , "shawn.guo@linaro.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v8 2/2] ARM: imx: support suspend states on imx7D Message-ID: <20150918141524.GC3770@tiger> References: <1438378439-11569-1-git-send-email-shenwei.wang@freescale.com> <1438378439-11569-3-git-send-email-shenwei.wang@freescale.com> <20150907151106.GA30723@tiger> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 On Tue, Sep 08, 2015 at 03:01:07PM +0000, Shenwei Wang wrote: > > > arch/arm/mach-imx/Kconfig | 1 + > > > arch/arm/mach-imx/Makefile | 2 + > > > arch/arm/mach-imx/common.h | 4 + > > > arch/arm/mach-imx/pm-imx7.c | 917 > > +++++++++++++++++++++++++++++++++++++++ > > > arch/arm/mach-imx/suspend-imx7.S | 529 ++++++++++++++++++++++ > > > 5 files changed, 1453 insertions(+) > > > > 1453 lines addition to kernel only for i.MX7D suspend support. Yes, this is the > > way we support suspend on i.MX6, but that's enough, and we have to stop this > > somewhere. I would ask you to take Sudeep's comment and adopt PSCI for > > i.MX7D power management. > > According to PSCI spec, a supervisory software must be implemented under either > HVC(EL2) or SMC(EL3) privilege level. I agree that, with this idea, we could finally move > these 1453 lines of codes from kernel into a platform specific firmware. The problem > is we don't have the firmware so far, and we haven't even had a plan to enable the > hypervisor or secure software on this platform. Because low power consumption is > the key feature of this i.MX7D platform, please continue to consider the current > implementation and get this feature supported first. Can't U-Boot be considered as a firmware to implement PSCI? I have seen an initial ARMv7 PSCI core support for U-Boot added by Marc Zyngier. Shawn [1] http://lists.denx.de/pipermail/u-boot/2013-December/168655.html