From mboxrd@z Thu Jan 1 00:00:00 1970 From: shawnguo@kernel.org (Shawn Guo) Date: Fri, 18 Sep 2015 22:15:24 +0800 Subject: [PATCH v8 2/2] ARM: imx: support suspend states on imx7D In-Reply-To: References: <1438378439-11569-1-git-send-email-shenwei.wang@freescale.com> <1438378439-11569-3-git-send-email-shenwei.wang@freescale.com> <20150907151106.GA30723@tiger> Message-ID: <20150918141524.GC3770@tiger> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.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