On Fri, Sep 18, 2015 at 02:38:39PM +0000, Shenwei Wang wrote: > > > > -----Original Message----- > > From: Shawn Guo [mailto:shawn...@kernel.org] > > Sent: 2015年9月18日 9:15 > > To: Wang Shenwei-B38339 > > Cc: ja...@lakedaemon.net; Huang Yongcai-B20788; > > linux-kernel@vger.kernel.org; ker...@pengutronix.de; Sudeep Holla; > > t...@linutronix.de; shawn....@linaro.org; > > linux-arm-ker...@lists.infradead.org > > Subject: Re: [PATCH v8 2/2] ARM: imx: support suspend states on imx7D > > > > 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. > > The current PSCI support in uboot is not complete. It can now support > cpuidle, shutdown, > and reset. But to support system suspend, there would be a lot more tasks. > For example, > even the current wakeup source management codes will have to move into the > firmware > too. It is not a short time task. Please continue to consider this platform > dependent implementation > first, meanwhile, we will start to migrate the solution to PSCI. However it > will take some time.
I have zero interest to maintain this pile of code in the mainline kernel. Take it as a motivation to move to PSCI soon, or you maintain it on your own as a out-of-tree patch for whatever long time you like. Shawn -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
