On 2021-01-21 13:32, Mark Rutland wrote:
On Thu, Jan 21, 2021 at 01:22:37PM +0000, Marc Zyngier wrote:
On 2021-01-21 12:50, Mohamed Mediouni wrote:
> > On 21 Jan 2021, at 13:44, Arnd Bergmann <a...@kernel.org> wrote:
> >
> > On Wed, Jan 20, 2021 at 2:27 PM Mohamed Mediouni
[...]
> > > + aic.fast_ipi = of_property_read_bool(node, "fast-ipi");
> >
> > Where is this property documented, and what decides which one to use?
> It’s getting documented in the next patch set.
>
> This property is there to enable support for older iPhone processors
> later on, some of which do not have fast IPI support.
>
> On Apple M1, fast-ipi is always on.
Then please focus on a single implementation. Additional features can
always be merged later once something is up and running.
Also, there sysregs can be detected by matching the MIDR, so I don't
think we need a DT property for that.
Generally we do not detect IMP-DEF sysregs based on MIDR because they
won't necessarily be exposed to a VM, so I suspect that we do need DT
properties to describe that IMP-DEF sysregs are accessible, and should
not rely on the MIDR alone. Maybe that's implicit in another property,
but worth bearing in mind.
Hmm. That's a good point. I think this could be keyed off
the compatible property, which should accurately reflect
the version of the interrupt controller.
Thanks,
M.
--
Jazz is not dead. It just smells funny...