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SubjectRe: [PATCH 17/18] arm64: dts: Convert to the hierarchical CPU topology layout for MSM8916
On Mon, May 13, 2019 at 09:22:59PM +0200, Ulf Hansson wrote:
> From: Lina Iyer <lina.iyer@linaro.org>
>
> In the hierarchical layout, we are creating power domains around each CPU
> and describes the idle states for them inside the power domain provider
> node. Note that, the CPU's idle states still needs to be compatible with
> "arm,idle-state".
>
> Furthermore, represent the CPU cluster as a separate master power domain,
> powering the CPU's power domains. The cluster node, contains the idle
> states for the cluster and each idle state needs to be compatible with the
> "domain-idle-state".
>
> If the running platform is using a PSCI FW that supports the OS initiated
> CPU suspend mode, which likely should be the case unless the PSCI FW is
> very old, this change triggers the PSCI driver to enable it.
>
> Cc: Andy Gross <andy.gross@linaro.org>
> Cc: David Brown <david.brown@linaro.org>
> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
> Co-developed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---

[...]

> @@ -166,12 +170,57 @@
> min-residency-us = <2000>;
> local-timer-stop;
> };
> +
> + CLUSTER_RET: cluster-retention {
> + compatible = "domain-idle-state";
> + arm,psci-suspend-param = <0x1000010>;
> + entry-latency-us = <500>;
> + exit-latency-us = <500>;
> + min-residency-us = <2000>;
> + };
> +
> + CLUSTER_PWRDN: cluster-gdhs {
> + compatible = "domain-idle-state";
> + arm,psci-suspend-param = <0x1000030>;
> + entry-latency-us = <2000>;
> + exit-latency-us = <2000>;
> + min-residency-us = <6000>;
> + };
> };
> };

I was trying to understand the composition of composite state parameters
in this series and that made me look at these DT examples.

What format does the above platform use ? I tried matching them to
both original as well as extended format and I fail to understand.
Assuming original format:
State power_state PowerLevel StateType StateID
SPC 0x40000002 0(core) 0(Retention) 0x2 (Res0 b[29]=1?)
CLUSTER_RET 0x1000010 1(clusters) 0(Retention) 0x10
CLUSTER_PWRDN 0x1000030 1(clusters) 0(Retention?) 0x30
Now extended format:
State power_state StateType StateID
SPC 0x40000002 0(Retention) 0x40000002 (Res0 b[29]=1?)
CLUSTER_RET 0x1000010 0(Retention) 0x1000010
CLUSTER_PWRDN 0x1000030 0(Retention?) 0x1000030

What am I missing ?

--
Regards,
Sudeep

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