Re: [PATCH 13/36] dt-bindings: arm: Convert PMU binding to json-schema

[Thomas Petazzoni]

Hello,

I'm jumping into the discussion, but I clearly don't have all the
context of the discussion.

On Thu, 8 Nov 2018 15:54:31 +0000, Robin Murphy wrote:

> >> This seems like a semantic different between the two representations, or am
> >> I missing something here? Specifically, both the introduction of
> >> interrupts-extended and also dropping any mention of using a single per-cpu
> >> interrupt (the single combined case is no longer support by Linux; not sure
> >> if you want to keep it in the binding).  
> > 
> > In regards to no support for the single combined interrupt, it looks
> > like Marvell Armada SoCs at least (armada-375 is what I'm looking at)
> > have only a single interrupt. Though the interrupt gets routed to MPIC
> > which then has a GIC PPI. So it isn't supported or happens to work
> > still since it is a PPI?  
> 
> Well, the description of the MPIC in the Armada XP functional spec says:
> 
> "Interrupt sources ID0âID28 are private events per CPU. Thus, each 
> processor has a different set of events map interrupts ID0âID28."
> 
> Odd grammar aside, that would seem to imply that <&mpic 3> is a per-cpu 
> interrupt itself, thus AFAICS so long as it's cascaded to a GIC PPI and 
> not an SPI then there's no issue there.

The Armada XP does not have a GIC at all, but only a MPIC as the
primary interrupt controller.

However the Armada 38x has both a GIC and a MPIC, and indeed the parent
interrupts of the MPIC towards the GIC is:

	interrupts = <GIC_PPI 15 IRQ_TYPE_LEVEL_HIGH>;

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com