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:

quoted

quoted

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 ID0–ID28 are private events per CPU. Thus, each 
processor has a different set of events map interrupts ID0–ID28."

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