On Fri, 29 Mar 2013, Rob Herring wrote: > On 03/29/2013 12:53 PM, Nicolas Pitre wrote: > > On Fri, 29 Mar 2013, Stefano Stabellini wrote: > > > >> 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.stabell...@eu.citrix.com> > >>>> CC: will.dea...@arm.com > >>>> CC: a...@arndb.de > >>>> CC: marc.zyng...@arm.com > >>>> CC: li...@arm.linux.org.uk > >>>> CC: n...@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. > > > > Maybe I'm missing something obvious, but why can't xen declare a mdesc > > of its own? Given it is going to tweak the DT passed to the kernel > > anyway that shouldn't be a problem. > > Xen does have it's own mdesc. It is (or will be) mach-virt, but that is > only for DomU guests. For Dom0, you still need all the platform specific > code except smp_ops. However, I'm doubtful this would work without other > changes on more complicated platforms like OMAP. > > I would say wait to add this until you have platforms that actually need > the first case.
OK, that is not unreasonable. What are the platforms that are going to use smp_init? Do we know how do they intend to use it? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
