[PATCH v4 2/2] arm: prefer PSCI for SMP bringup

[Stefano Stabellini]

On Fri, 29 Mar 2013, Nicolas Pitre wrote:
> On Fri, 29 Mar 2013, Stefano Stabellini wrote:
> 
> > If PSCI initializes correctly and PSCI SMP operations are available, use them.
> > This is required for SMP support in Dom0 on Xen.
> > 
> > Signed-off-by: Stefano Stabellini <stefano.stabellini at eu.citrix.com>
> > CC: will.deacon at arm.com
> > CC: arnd at arndb.de
> > CC: marc.zyngier at arm.com
> > CC: linux at arm.linux.org.uk
> > CC: nico at linaro.org
> 
> I'd suggest you also include in your series the patch I posted earlier 
> providing a runtime mdesc->smp_init method as well.

OK.


> This way the 
> priority order would be:
> 
> - If mdesc->smp_init is non null then use that.
> 
> - Otherwise, if PSCI is available then use that.
> 
> - Otherwise use mdesc->smp.
> 
> This way, if the PSCI default has to be overriden (like in the MCPM case 
> because it needs to wrap PSCI itself, or to cover Rob's concern) then 
> this can be achieved at run time on a per mdesc basis.

Actually that's not a bad idea, it could make everybody happy.
What about the following, in this precise order:

- if a xen hypervisor node is present on device tree, use PSCI;
- otherwise if mdesc->smp_init is non null then use it;
- otherwise if PSCI is available then use it;
- otherwise use mdesc->smp.

It's the most practical solution to satisfy everybody's needs.