RE: [PATCH] arm64: dts: Added syscon-reboot node for FSL's LS2085A SoC

[Stuart Yoder]

> -----Original Message-----
> From: Arnd Bergmann [mailto:arnd@xxxxxxxx]
> Sent: Friday, October 30, 2015 8:36 AM
> To: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Cc: Yoder Stuart-B08248; Mark Rutland; devicetree@xxxxxxxxxxxxxxx; Sharma Bhupesh-B45370; Rivera Jose-B46482;
> linux-kernel@xxxxxxxxxxxxxxx; robh+dt@xxxxxxxxxx; Li Yang-Leo-R58472
> Subject: Re: [PATCH] arm64: dts: Added syscon-reboot node for FSL's LS2085A SoC
> 
> On Tuesday 27 October 2015 18:25:04 Stuart Yoder wrote:
> > I think that comment "Currently supported enable-method is psci v0.2" is a statement of
> > intent, not what is available currently.   And the only plan I am aware of is PSCI
> > with UEFI based firmware.
> >
> > U-boot is a key firmware platform for us and has no PSCI implementation available.
> 
> I believe U-boot has supported PSCI since 2013. Maybe you just need to update
> to a newer version?

We are using a very recent u-boot.  U-boot for ARMv8, which is what this SoC is
based on, does not have PSCI as far as I can tell.  We (Freescale) plan to 
eventually have an EL3 firmware component that could remain resident for 
u-boot based systems, but it is a roadmap thing and I don't know when
we're going to get it.

So, for now, most straightforward thing is to get reboot functionality is
to expose the reset register via syscon-reboot in the DT...no new driver needed.

Once a PSCI component is available we'll move to it.

Thanks,
Stuart
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