Re: [PATCH v2] arm64: dts: sdm845: Add PSCI cpuidle low power states
From: Amit Kucheria
Date: Tue May 07 2019 - 18:21:49 EST
On Tue, Oct 30, 2018 at 10:53 PM Raju P.L.S.S.S.N
<rplsssn@xxxxxxxxxxxxxx> wrote:
>
> Add device bindings for cpuidle states for cpu devices.
Raju: Did this patch fall through the cracks? It would be nice to land
this while Lina works on setting up the infrastructure to do
hierarchical power domains.
> Cc: <devicetree@xxxxxxxxxxxxxxx>
> Signed-off-by: Raju P.L.S.S.S.N <rplsssn@xxxxxxxxxxxxxx>
> ---
> Changes in v2
> - Address comments from Doug
> ---
> ---
> arch/arm64/boot/dts/qcom/sdm845.dtsi | 62 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 62 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/qcom/sdm845.dtsi b/arch/arm64/boot/dts/qcom/sdm845.dtsi
> index 0c9a2aa..3a8381e 100644
> --- a/arch/arm64/boot/dts/qcom/sdm845.dtsi
> +++ b/arch/arm64/boot/dts/qcom/sdm845.dtsi
> @@ -96,6 +96,7 @@
> reg = <0x0 0x0>;
> enable-method = "psci";
> next-level-cache = <&L2_0>;
> + cpu-idle-states = <&C0_CPU_PD &C0_CPU_RPD &CLUSTER_PD>;
May I suggest using more generic names here instead of C0_CPU_PD and
move the QC-specific description to the idle-state-name property? C0
and C4 isn't easy to understand at a glance. Neither is PD and RPD.
Something like big_cpu_retention, big_cpu_sleep, little_cpu_retention,
little_cpu_sleep, cluster_sleep?
Or big_cpu_idle_0, big_cpu_idle_1, big_cpu_idle_2 for states with
increasing breakeven times.
I've commented below on what it might look like.
> L2_0: l2-cache {
> compatible = "cache";
> next-level-cache = <&L3_0>;
> @@ -111,6 +112,7 @@
> reg = <0x0 0x100>;
> enable-method = "psci";
> next-level-cache = <&L2_100>;
> + cpu-idle-states = <&C0_CPU_PD &C0_CPU_RPD &CLUSTER_PD>;
> L2_100: l2-cache {
> compatible = "cache";
> next-level-cache = <&L3_0>;
> @@ -123,6 +125,7 @@
> reg = <0x0 0x200>;
> enable-method = "psci";
> next-level-cache = <&L2_200>;
> + cpu-idle-states = <&C0_CPU_PD &C0_CPU_RPD &CLUSTER_PD>;
> L2_200: l2-cache {
> compatible = "cache";
> next-level-cache = <&L3_0>;
> @@ -135,6 +138,7 @@
> reg = <0x0 0x300>;
> enable-method = "psci";
> next-level-cache = <&L2_300>;
> + cpu-idle-states = <&C0_CPU_PD &C0_CPU_RPD &CLUSTER_PD>;
> L2_300: l2-cache {
> compatible = "cache";
> next-level-cache = <&L3_0>;
> @@ -147,6 +151,7 @@
> reg = <0x0 0x400>;
> enable-method = "psci";
> next-level-cache = <&L2_400>;
> + cpu-idle-states = <&C4_CPU_PD &C4_CPU_RPD &CLUSTER_PD>;
> L2_400: l2-cache {
> compatible = "cache";
> next-level-cache = <&L3_0>;
> @@ -159,6 +164,7 @@
> reg = <0x0 0x500>;
> enable-method = "psci";
> next-level-cache = <&L2_500>;
> + cpu-idle-states = <&C4_CPU_PD &C4_CPU_RPD &CLUSTER_PD>;
> L2_500: l2-cache {
> compatible = "cache";
> next-level-cache = <&L3_0>;
> @@ -171,6 +177,7 @@
> reg = <0x0 0x600>;
> enable-method = "psci";
> next-level-cache = <&L2_600>;
> + cpu-idle-states = <&C4_CPU_PD &C4_CPU_RPD &CLUSTER_PD>;
> L2_600: l2-cache {
> compatible = "cache";
> next-level-cache = <&L3_0>;
> @@ -183,11 +190,66 @@
> reg = <0x0 0x700>;
> enable-method = "psci";
> next-level-cache = <&L2_700>;
> + cpu-idle-states = <&C4_CPU_PD &C4_CPU_RPD &CLUSTER_PD>;
> L2_700: l2-cache {
> compatible = "cache";
> next-level-cache = <&L3_0>;
> };
> };
> +
> + idle-states {
> + entry-method = "psci";
> +
> + C0_CPU_PD: c0-power-down {
big_cpu_retention: big-cpu-retention
> + compatible = "arm,idle-state";
> + arm,psci-suspend-param = <0x40000003>;
> + entry-latency-us = <350>;
> + exit-latency-us = <461>;
> + min-residency-us = <1890>;
> + local-timer-stop;
> + idle-state-name = "power-down";
"big-cpu-power-down"
> + };
> +
> + C0_CPU_RPD: c0-rail-power-down {
big_cpu_sleep: big-cpu-sleep
> + compatible = "arm,idle-state";
> + arm,psci-suspend-param = <0x40000004>;
> + entry-latency-us = <360>;
> + exit-latency-us = <531>;
> + min-residency-us = <3934>;
> + local-timer-stop;
> + idle-state-name = "rail-power-down";
"big-cpu-rail-power-down"
> + };
> +
> + C4_CPU_PD: c4-power-down {
little_cpu_retention: little-cpu-retention
> + compatible = "arm,idle-state";
> + arm,psci-suspend-param = <0x40000003>;
> + entry-latency-us = <264>;
> + exit-latency-us = <621>;
> + min-residency-us = <952>;
> + local-timer-stop;
> + idle-state-name = "power-down";
"little-cpu-power-down" and so and so forth. You get the idea.
> + };
> +
> + C4_CPU_RPD: c4-rail-power-down {
> + compatible = "arm,idle-state";
> + arm,psci-suspend-param = <0x40000004>;
> + entry-latency-us = <702>;
> + exit-latency-us = <1061>;
> + min-residency-us = <4488>;
> + local-timer-stop;
> + idle-state-name = "rail-power-down";
> + };
> +
> + CLUSTER_PD: cluster-power-down {
> + compatible = "arm,idle-state";
> + arm,psci-suspend-param = <0x400000F4>;
> + entry-latency-us = <3263>;
> + exit-latency-us = <6562>;
> + min-residency-us = <9987>;
> + local-timer-stop;
> + idle-state-name = "cluster-power-down";
> + };
> + };
> };
>
> pmu {
> --
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