quoted
Orion use generic chip interrupts, both for the main interrupts and
the GPIO interrupts. This does not yet support irq domain, so i have
to layer a legacy domain on top. The legacy domain needs to know the
first IRQ and the number of IRQs. For the primary IRQs that is
easy. However, GPIO IRQ is not so easy, it depends on how many primary
IRQs there are. This is not fixed. Orion5x has 32, Dove 64, kirkwood,
64, and mv78xx0 has 96. I need to know this number when adding the
GPIO secondary IRQ legacy domain. By calling orion_gpio_of_init() in
the orion_add_irq_domain() i have this number to hand. If i used to
entries in the match table, i would have to put this number into some
global variable, or somehow ask the IRQ subsystem what the next free
IRQ number is.
But couldn't you store the number of interrupts for the primary controller
in a local variable? I think the of_irq code already guarantees that
the parent is probed first.
Sure i could. But what is the advantage of that?
Andrew