[PATCH 4/6] arm64/ls1043a: add DTS for Freescale LS1043A SoC

[Sharma Bhupesh]

> -----Original Message-----
> From: Li Yang-Leo-R58472
> Sent: Tuesday, September 22, 2015 10:53 PM
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> Subject: RE: [PATCH 4/6] arm64/ls1043a: add DTS for Freescale LS1043A SoC
> 
> > >
> > > Hi,
> > >
> > > > +/memreserve/ 0x80000000 0x00010000;
> > >
> > > Why is this necessary?
> >
> > This memory region is pre-reserved for the spin-table/psci, although
> > didn't add Enable method of secondary cores.
> 
> Can this be reserved by bootloader?

No need to reserve this for PSCI based secondary bootup.

> >
> > > If this is necessary, please add a comment stating what this is for.
> > >
> > > > +               cpu at 3 {
> > > > +                       device_type = "cpu";
> > > > +                       compatible = "arm,cortex-a53";
> > > > +                       reg = <0x0 0x3>;
> > > > +                       clocks = <&clockgen 1 0>;
> > > > +               };
> > >
> > > Missing enable-method properties on all the secondary CPUs.
> > >
> >
> > There are two methods (spin-table and psci) to bring up secondary
> > cores, which one do you think is better?
> 
> Do we have the PSCI support ready in both UEFI and u-boot?  If not, we
> should use spin-table for now.

UEFI has been using PSCI with Arm Trusted Firmware (ATF) since some time. U-boot can also work with ATF seamlessly.

Spin-table method is deprecated and newer patches should support PSCI. If not, all intelligence should be left to the
Bootloader and the Linux DTS should not mention the 'enable-method' and the 'memreserve' regions. 

For details please see the LS2085A Freescale DTS already present in mainline kernel.

Regards,
Bhupesh