Re: [PATCH v5 8/8] arm64: boot: dts: update rtsm aemv8 dts with PSCI and idle states

Mark Rutland
2014-06-25T14:27:19Z

Hi Lorenzo,

On Wed, Jun 25, 2014 at 03:10:21PM +0100, Lorenzo Pieralisi wrote:
> This patch updates the RTSM dts file with PSCI bindings and nodes
> describing the AEMv8 model idle states parameters.
>
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> ---
> arch/arm64/boot/dts/rtsm_ve-aemv8a.dts | 44 +++++++++++++++++++++++++++-------
> 1 file changed, 36 insertions(+), 8 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/rtsm_ve-aemv8a.dts b/arch/arm64/boot/dts/rtsm_ve-aemv8a.dts
> index d79de9c..4051ffb 100644
> --- a/arch/arm64/boot/dts/rtsm_ve-aemv8a.dts
> +++ b/arch/arm64/boot/dts/rtsm_ve-aemv8a.dts
> @@ -27,37 +27,65 @@
> serial3 = &v2m_serial3;
> };
>
> + psci {
> + compatible = "arm,psci-0.2";

Where can I find a PSCI 0.2 implementation for the RTSM VE model? I
couldn't find a link in the cover.

The upstream bootwrapper is not PSCI 0.2 compliant and it does not
implement CPU_SUSPEND.

> + method = "smc";
> + cpu_suspend = <0xc4000001>;
> + cpu_off = <0x84000002>;
> + cpu_on = <0xc4000003>;

Without "arm,psci" in the compatible list, these three properties are
meaningless.

> + };
> +
> cpus {
> #address-cells = <2>;
> #size-cells = <0>;
>
> + idle-states {
> + entry-method = "arm,psci";
> +
> + CPU_SLEEP_0: cpu-sleep-0 {
> + compatible = "arm,idle-state";
> + entry-method-param = <0x0010000>;
> + entry-latency-us = <40>;
> + exit-latency-us = <100>;
> + min-residency-us = <150>;
> + };
> +
> + CLUSTER_SLEEP_0: cluster-sleep-0 {
> + compatible = "arm,idle-state";
> + entry-method-param = <0x1010000>;
> + entry-latency-us = <500>;
> + exit-latency-us = <1000>;
> + min-residency-us = <2500>;
> + };
> + };
> +

If this is going to live in the /cpus node, could it please be placed
after the cpu nodes?

> cpu@0 {
> device_type = "cpu";
> compatible = "arm,armv8";
> reg = <0x0 0x0>;
> - enable-method = "spin-table";
> - cpu-release-addr = <0x0 0x8000fff8>;
> + enable-method = "psci";

Changing the enable-method will break boot on a model when using a
bootwrapper without PSCI support. Really we should leave it up to the
bootwrapper to inject the enable method...

Mark.