From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: Re: [PATCH v7 2/8] Documentation: arm: define DT idle states bindings Date: Mon, 18 Aug 2014 15:20:41 +0100 Message-ID: <20140818142041.GC20043@localhost> References: <1407945127-27554-1-git-send-email-lorenzo.pieralisi@arm.com> <1407945127-27554-3-git-send-email-lorenzo.pieralisi@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1407945127-27554-3-git-send-email-lorenzo.pieralisi@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Lorenzo Pieralisi Cc: Mark Rutland , Tomasz Figa , Lina Iyer , Chander Kashyap , Vincent Guittot , Nicolas Pitre , Daniel Lezcano , "linux-arm-kernel@lists.infradead.org" , "grant.likely@linaro.org" , Charles Garcia-Tobin , "devicetree@vger.kernel.org" , Kevin Hilman , "linux-pm@vger.kernel.org" , Sebastian Capella , Mark Brown , Antti Miettinen , Paul Walmsley , Geoff Levand , Peter De Schrijver , Stephen Boyd , Amit Kucheria List-Id: devicetree@vger.kernel.org On Wed, Aug 13, 2014 at 04:52:01PM +0100, Lorenzo Pieralisi wrote: > ARM based platforms implement a variety of power management schemes that > allow processors to enter idle states at run-time. > The parameters defining these idle states vary on a per-platform basis forcing > the OS to hardcode the state parameters in platform specific static tables > whose size grows as the number of platforms supported in the kernel increases > and hampers device drivers standardization. > > Therefore, this patch aims at standardizing idle state device tree bindings > for ARM platforms. Bindings define idle state parameters inclusive of entry > methods and state latencies, to allow operating systems to retrieve the > configuration entries from the device tree and initialize the related power > management drivers, paving the way for common code in the kernel to deal with > idle states and removing the need for static data in current and previous > kernel versions. > > ARM64 platforms require the DT to define an entry-method property > for idle states. > > On system implementing PSCI as an enable-method to enter low-power > states the PSCI CPU suspend method requires the power_state parameter to > be passed to the PSCI CPU suspend function. > > This parameter is specific to a power state and platform specific, > therefore must be provided by firmware to the OS in order to enable > proper call sequence. > > Thus, this patch also adds a property in the PSCI bindings that > describes how the PSCI CPU suspend power_state parameter should be > defined in DT in all device nodes that rely on PSCI CPU suspend method usage. > > Acked-by: Daniel Lezcano > Acked-by: Nicolas Pitre > Reviewed-by: Rob Herring > Reviewed-by: Sebastian Capella > Signed-off-by: Lorenzo Pieralisi > --- > Documentation/devicetree/bindings/arm/cpus.txt | 8 + > .../devicetree/bindings/arm/idle-states.txt | 679 +++++++++++++++++++++ > Documentation/devicetree/bindings/arm/psci.txt | 14 +- > 3 files changed, 700 insertions(+), 1 deletion(-) > create mode 100644 Documentation/devicetree/bindings/arm/idle-states.txt Acked-by: Catalin Marinas From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Mon, 18 Aug 2014 15:20:41 +0100 Subject: [PATCH v7 2/8] Documentation: arm: define DT idle states bindings In-Reply-To: <1407945127-27554-3-git-send-email-lorenzo.pieralisi@arm.com> References: <1407945127-27554-1-git-send-email-lorenzo.pieralisi@arm.com> <1407945127-27554-3-git-send-email-lorenzo.pieralisi@arm.com> Message-ID: <20140818142041.GC20043@localhost> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Aug 13, 2014 at 04:52:01PM +0100, Lorenzo Pieralisi wrote: > ARM based platforms implement a variety of power management schemes that > allow processors to enter idle states at run-time. > The parameters defining these idle states vary on a per-platform basis forcing > the OS to hardcode the state parameters in platform specific static tables > whose size grows as the number of platforms supported in the kernel increases > and hampers device drivers standardization. > > Therefore, this patch aims at standardizing idle state device tree bindings > for ARM platforms. Bindings define idle state parameters inclusive of entry > methods and state latencies, to allow operating systems to retrieve the > configuration entries from the device tree and initialize the related power > management drivers, paving the way for common code in the kernel to deal with > idle states and removing the need for static data in current and previous > kernel versions. > > ARM64 platforms require the DT to define an entry-method property > for idle states. > > On system implementing PSCI as an enable-method to enter low-power > states the PSCI CPU suspend method requires the power_state parameter to > be passed to the PSCI CPU suspend function. > > This parameter is specific to a power state and platform specific, > therefore must be provided by firmware to the OS in order to enable > proper call sequence. > > Thus, this patch also adds a property in the PSCI bindings that > describes how the PSCI CPU suspend power_state parameter should be > defined in DT in all device nodes that rely on PSCI CPU suspend method usage. > > Acked-by: Daniel Lezcano > Acked-by: Nicolas Pitre > Reviewed-by: Rob Herring > Reviewed-by: Sebastian Capella > Signed-off-by: Lorenzo Pieralisi > --- > Documentation/devicetree/bindings/arm/cpus.txt | 8 + > .../devicetree/bindings/arm/idle-states.txt | 679 +++++++++++++++++++++ > Documentation/devicetree/bindings/arm/psci.txt | 14 +- > 3 files changed, 700 insertions(+), 1 deletion(-) > create mode 100644 Documentation/devicetree/bindings/arm/idle-states.txt Acked-by: Catalin Marinas