IRQ numbering (was: Better timer and RTC handling for 8641HPCN.)

[Paul Mackerras]

Zhang Wei-r63237 writes:

> I think creating some debugfs or sysfs info that translates VIRQ to HW
> irq is a _good_ idea, or just add some fields (irq host, hwirq) in
> /proc/interrupts. If we have this, I'll fix all irqs in dts file and
> remove the fake irq hole.

It would have to be a (host, hwirq) pair.  A "hwirq" has no meaning by
itself, since in general we can have multiple interrupt controllers
and they will each have their own space of interrupt numbers.

> Before we have a virq-hwirq mapping list, I keep my option about the irq
> number.

There is no point trying to fake things up in the .dts so that you get
virq numbers that you expect.  The numbers in the .dts should be the
controller-relative "hwirq" numbers.

Paul.