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. Thanks, Mark.
