Re: [Xen-devel] [PATCH 1/4] arm: parse PSCI node from the host device-tree

[Andre Przywara <andre.przywara@xxxxxxxxxx>]

On 11/26/2013 12:12 PM, Ian Campbell wrote:
> On Mon, 2013-11-25 at 13:02 +0100, Andre Przywara wrote:
> > +
> > +    if ( !dt_property_read_u32(psci, "cpu_on", &psci_host_cpu_on_nr) )
> > +    {
> > +        printk("/psci node is missing the \"cpu_on\" property\n");
> > +        return 4;
> > +    }
> http://www.spinics.net/lists/devicetree/msg05348.html updates the
> bindings for PSCI 0.2. I suppose Midway must only support 0.1?
>
> I'd be OK with only supporting 0.1 right now, but it would be useful to
> comment either in the code or in the commit message.
>
> (nb: I'm not sure of v4 was the final version of that series)
If I look at http://www.spinics.net/lists/devicetree/msg12293.html
I would keep it as it is - at least until the binding changes. Hopefully 
there will be a compatibility fallback if cpu_on should change to 
cpu_on-{32,64}. I will talk to Rob about this and will later send a fix 
if that is needed.
Midway provides an implementation conforming to PSCI 0.2, however the 
device tree binding is still the one from the current kernel git HEAD.
> > +
> > +    return 0;
> > +}
> > +
> >   /* Parse the device tree and build the logical map array containing
> >    * MPIDR values related to logical cpus
> >    * Code base on Linux arch/arm/kernel/devtree.c
> > @@ -107,6 +145,11 @@ void __init smp_init_cpus(void)
> >       bool_t bootcpu_valid = 0;
> >       int rc;
> >
> > +    if ( psci_host_init() == 0 )
> > +    {
> > +        printk(XENLOG_INFO "Using PSCI for SMP bringup\n");
> > +    }
> > +
> >       if ( (rc = arch_smp_init()) < 0 )
> arch_smp_init is empty on both platforms. arm32 has a comment "TODO:
> PSCI" ;-)
>
> I think we can nuke this function while we are here, since it's only
> purpose was as a PSCI placehoder.
But arch_smp_init() calls platform_smp_init(), which is not empty for 
the Exynos, VExpress and OMAP5 (it contains the native SMP bringup for 
these platforms).
So shall I skip the superfluous arch_smp_init() and call 
platform_smp_init() directly from smpboot.c?
Or keep it as it is and we clean it up later?

Thanks,
Andre.


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