Re: [PATCH 17/18] arm64: dts: Convert to the hierarchical CPU topology layout for MSM8916

[Sudeep Holla <sudeep.holla@arm.com>]

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