Chander Kashyap wrote:
>
> Exynos7 supports multiple idle states. Core power down is one such
> idle state, where cores can be powered off independently.
>
> This patch adds support for core power down idle state.
>
> Entry latency for core power down idle state is calculated as follows:
> 1. Time difference is measured between cpuidle entry and exit.
> 2. WFI is skipped for measuring the time.
> 3. Select the worst case time in a set of 100000 cpuidle transactions,
> with varying load.
>
> Exit latency and min residency values are supplied as per HW team.
>
> Signed-off-by: Chander Kashyap <k.chan...@samsung.com>
> Acked-by: Lorenzo Pieralisi <lorenzo.pieral...@arm.com>
Lorenzo, thanks for your ack. Will apply.
- Kukjin
> ---
> This patch has following dependencies:
> - [PATCH v5 0/8] arch: arm64: Enable support for Samsung Exynos7 SoC
> www.spinics.net/lists/arm-kernel/msg375961.html
> Changes in v2:
> - Moved the cpu-idle-state property after reg property
> - removed the status property.
> Changes in v3:
> - Added the Entry latency calculation in commit message.
> Changes in v4:
> - Corrected the commit message.
> - Corrected the entry latency value.
> Changes in v5:
> - Commit message modified
>
> arch/arm64/boot/dts/exynos/exynos7.dtsi | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/exynos/exynos7.dtsi
> b/arch/arm64/boot/dts/exynos/exynos7.dtsi
> index d7a37c3..891eef4 100644
> --- a/arch/arm64/boot/dts/exynos/exynos7.dtsi
> +++ b/arch/arm64/boot/dts/exynos/exynos7.dtsi
> @@ -37,6 +37,7 @@
> compatible = "arm,cortex-a57", "arm,armv8";
> reg = <0x0>;
> enable-method = "psci";
> + cpu-idle-states = <&CPU_SLEEP>;
> };
>
> cpu@1 {
> @@ -44,6 +45,7 @@
> compatible = "arm,cortex-a57", "arm,armv8";
> reg = <0x1>;
> enable-method = "psci";
> + cpu-idle-states = <&CPU_SLEEP>;
> };
>
> cpu@2 {
> @@ -51,6 +53,7 @@
> compatible = "arm,cortex-a57", "arm,armv8";
> reg = <0x2>;
> enable-method = "psci";
> + cpu-idle-states = <&CPU_SLEEP>;
> };
>
> cpu@3 {
> @@ -58,6 +61,20 @@
> compatible = "arm,cortex-a57", "arm,armv8";
> reg = <0x3>;
> enable-method = "psci";
> + cpu-idle-states = <&CPU_SLEEP>;
> + };
> +
> + 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 = <34>;
> + exit-latency-us = <150>;
> + min-residency-us = <2100>;
> + };
> };
> };
>
> --
> 1.9.1
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