Re: [PATCH 3/4] arm64: dts: Add mediatek MT8173 SoC and evaluation board dts and Makefile

[Eddie Huang <eddie.huang@mediatek.com>]

Hi,

On Mon, 2014-12-15 at 12:59 +0000, Mark Rutland wrote:
> On Fri, Dec 12, 2014 at 08:08:25AM +0000, Eddie Huang wrote:
> > Hi Mark,
> > 
> > On Thu, 2014-12-11 at 18:02 +0000, Mark Rutland wrote:
> > > Hi,
> > > 
> > > On Wed, Dec 10, 2014 at 10:50:01AM +0000, Eddie Huang wrote:
> > > > Add device tree support for MT8173 SoC and evalutaion board based on it.
> > > > 
> > 
> > > > +
> > > > +	psci {
> > > > +		compatible = "arm,psci-0.2";
> > > > +		method = "smc";
> > > > +	};
> > > 
> > > What are you using as your PSCI 0.2 implementation?
> > > 
> > > Is it fully compliant? (e.g. are the reset and power off functions
> > > implemented, may CPU0 be hotplugged)?
> > > 
> > > Given only portions of the GIC seem to be described below, what
> > > exception level is your kernel entered at? Per the spec it should be
> > > EL2, but given the brokenness below with the GIC I'm suspicious.
> > > 
> > 
> > Currently we only implement CPU boot, no power off, no CPU0 hotplug
> > either. And enter kernel at EL2. Actually, we run ATF in EL3, then
> > switch to EL2 to run lk and kernel.
> 
> Ok. In the absence of CPU_OFF, this is not yet a conforming PSCI 0.2
> implementation, so I'm wary of marking this as PSCI 0.2 until that is
> the case. Any attempt to power of CPUs will hit a BUG() in cpu_die(),
> and we don't want that.

We are still developing PSCI related functions, CPU_ON, CPU_OFF,
CPU_SUSPEND are ready, others are going. PSCI 0.2 is our target although
lacks some implements

> 
> Is CPU0 hotplug planned?

No

> 
> If not, does your PSCI implementation report CPU0 as
> non-hotpluggable via MIGRATE_INFO_TYPE reporting a UP not migratable
> trusted OS (and MIGRATE_INFO_UP_CPU reporting CPU0 as the resident CPU)?
> 
Will check whether add this

> Are SYSTEM_OFF and SYSTEM_RESET available?

No yet

> 
> Thanks,
> Mark.

Since we miss some PSCI-0.2 implements, I don't know whether I should
remove PSCI stuff in this patch.