Re: [PATCH v4 5/5] arm64: dts: Add dts files for Hisilicon Hi6220 SoC

[Mark Rutland <mark.rutland@arm.com>]

On Wed, May 06, 2015 at 04:51:20AM +0100, Leo Yan wrote:
> On Wed, May 06, 2015 at 11:16:12AM +0800, Bintian Wang wrote:
> > On 2015/5/6 1:13, Mark Rutland wrote:
> > >[...]
> > >
> > >>+	psci {
> > >>+		compatible = "arm,psci-0.2";
> > >>+		method = "smc";
> > >>+	};
> > >
> > >Are all the PSCI 0.2 mandatory features implemented?
> >
> > The system off/suspend is under development, and system off will
> > be released in next months, and system suspend may be released in the
> > following two months.
> 
> Yes; now for mandatory features, except SYSTEM_OFF others have supported.

Ok. Do you mean in the next month, or in a number of months?

> for PSCI 0.2, SYSTEM_SUSPEND even is not supported, right?

SYSTEM_SUSPEND was introduced in PSCI 1.0, and is optional.

So long as PSCI_VERSION reports 0.2 or PSCI_FEATURES reports
NOT_SUPPORTED for SYSTEM_SUSPEND, it's ok to not implement.

I guess PSCI_VERSION reports PSCI 0.2?

> > So can I keep "arm,psci-0.2" here?
> > 
> > >Can CPU0 be hot unplugged?
> > Yes, CPU0~CPU7 all can be hot unplugged.
> 
> Just clarify: now use s/w method to emulate CPU and cluster's low
> power state; all cores can be hotplugged [1].

So long as CPUs brought online are reset appropriately, and "offline"
CPUs can't bring down the system somehow, that should be fine. For now
the important part is the interface.

Thanks,
Mark.