Hi Lorenzo, On Wed, Oct 15, 2014 at 2:30 PM, Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> wrote: > On Wed, Oct 15, 2014 at 07:35:20AM +0100, Chander Kashyap wrote: >> Exynos7 has core power down state where cores can be powered off independently. >> This patch adds support for this state. > > Please tell us more about the idle-state values you are adding, in particular > entry, exit latencies and min-residency values. Entry latency: This value is calculated as follows: On entry to arm64_enter_idle_state: timestamp1 = ktimeget(); after returning from cpu_suspend() timestamp2 = ktimeget(); latency = timestamp2-timestamp1; Cpu is not allowed to enter core powerdown by skipping wfi instruction at end. Hence calculated time contains entry time + failure exit time. Regarding exit-latency and target-residency time, got these values from HW team. I am using these as initial values and I will be working on optimizing these values with further experiments. If you could suggest any formal method of deriving these values, i can try those methods as well. > >> Signed-off-by: Chander Kashyap <k.chander@xxxxxxxxxxx> >> --- >> This patch has following dependencies: >> - [PATCH v5 0/8] arch: arm64: Enable support for Samsung Exynos7 SoC >> http://www.spinics.net/lists/linux-samsung-soc/msg37047.html >> - [PATCH v9 0/8] ARM generic idle states >> http://permalink.gmane.org/gmane.linux.power-management.general/49224 > > Series above was merged, so dependency is stale. i will remove this > >> arch/arm64/boot/dts/exynos/exynos7.dtsi | 18 ++++++++++++++++++ >> 1 file changed, 18 insertions(+)dont >> >> diff --git a/arch/arm64/boot/dts/exynos/exynos7.dtsi b/arch/arm64/boot/dts/exynos/exynos7.dtsi >> index ce221ac..8e0a034 100644 >> --- a/arch/arm64/boot/dts/exynos/exynos7.dtsi >> +++ b/arch/arm64/boot/dts/exynos/exynos7.dtsi >> @@ -36,6 +36,7 @@ >> device_type = "cpu"; >> compatible = "arm,cortex-a57", "arm,armv8"; >> enable-method = "psci"; >> + cpu-idle-states = <&CPU_SLEEP>; > > I would add cpu-idle-states phandle after the reg property, as defined > in the idle states bindings. i will move this after reg property. > >> reg = <0x0>; >> }; >> >> @@ -43,6 +44,7 @@ >> device_type = "cpu"; >> compatible = "arm,cortex-a57", "arm,armv8"; >> enable-method = "psci"; >> + cpu-idle-states = <&CPU_SLEEP>; >> reg = <0x1>; >> }; >> >> @@ -50,6 +52,7 @@ >> device_type = "cpu"; >> compatible = "arm,cortex-a57", "arm,armv8"; >> enable-method = "psci"; >> + cpu-idle-states = <&CPU_SLEEP>; >> reg = <0x2>; >> }; >> >> @@ -57,8 +60,23 @@ >> device_type = "cpu"; >> compatible = "arm,cortex-a57", "arm,armv8"; >> enable-method = "psci"; >> + cpu-idle-states = <&CPU_SLEEP>; >> reg = <0x3>; >> }; >> + >> + idle-states { >> + entry-method = "arm,psci"; >> + >> + CPU_SLEEP: cpu-sleep { >> + compatible = "arm,idle-state"; >> + local-timer-stop; >> + arm,psci-suspend-param = <0x0010000>; >> + entry-latency-us = <20>; >> + exit-latency-us = <150>; >> + min-residency-us = <2100>; >> + status = "enabled"; > > status ? This is not a documented property. If you need it please explain > why, define its bindings and we can see how to accommodate it. I will add okay for status property. As per the bindings posted by you. regards, > > Thank you, > Lorenzo > >> + }; >> + }; >> }; >> >> psci { >> -- >> 1.7.9.5 >> >> > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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