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

[Ulf Hansson]

On Tue, 16 Jul 2019 at 16:47, Sudeep Holla <sudeep.holla@xxxxxxx> wrote:
>
> On Mon, May 13, 2019 at 09:23:00PM +0200, Ulf Hansson wrote:
> > To enable the OS to manage last-man standing activities for a CPU, while an
> > idle state for a group of CPUs is selected, let's convert the Hikey
> > platform into using the hierarchical CPU topology layout.
> >
> > Cc: Wei Xu <xuwei5@xxxxxxxxxxxxx>
> > Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> > ---
> >
> > Changes:
> >       - None.
> >
> > ---
> >  arch/arm64/boot/dts/hisilicon/hi6220.dtsi | 87 ++++++++++++++++++++---
> >  1 file changed, 76 insertions(+), 11 deletions(-)
> >
> > diff --git a/arch/arm64/boot/dts/hisilicon/hi6220.dtsi b/arch/arm64/boot/dts/hisilicon/hi6220.dtsi
> > index 108e2a4227f6..36ff460f428f 100644
> > --- a/arch/arm64/boot/dts/hisilicon/hi6220.dtsi
> > +++ b/arch/arm64/boot/dts/hisilicon/hi6220.dtsi
> >       cpus {
>
> [...]
>
> > @@ -70,9 +128,8 @@
> >                       };
> >
> >                       CLUSTER_SLEEP: cluster-sleep {
> > -                             compatible = "arm,idle-state";
> > -                             local-timer-stop;
> > -                             arm,psci-suspend-param = <0x1010000>;
> > +                             compatible = "domain-idle-state";
> > +                             arm,psci-suspend-param = <0x1000000>;
> >                               entry-latency-us = <1000>;
> >                               exit-latency-us = <700>;
> >                               min-residency-us = <2700>;
>
> Again this must be original format and as per PSCI spec, your patch
> changes this cluster sleep state into cluster retention state which I
> think is not what you intended.

If the hierarchical topology is used, the parameter for cluster states
are ORed with the deepest idle state for the CPU.

CPU_SLEEP: 0x0010000
CLUSTER_SLEEP: 0x1000000

After the ORed operation
CLUSTER_SLEEP: 0x1010000

So, this indeed works as expected.

However, are you saying that ORing the state parameters like above has
other problems? I am reading your other replies...

Kind regards
Uffe