Re: m68k: Convert to genirq (WIP)

From: Geert Uytterhoeven
Date: Tue May 31 2011 - 15:54:33 EST


Hi Thomas,

On Sat, May 28, 2011 at 20:32, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
> Next on my list is Amiga, which will cover autovectored and chained interrupts.

Plain chained interrupts should be handled by calling irq_set_chained_handler()
to register an irq_flow_handler_t, and let the handler call
generic_handle_irq() for
each successive interrupt, right?

However, on Amiga we have interrupts (IRQ_AMIGA_PORTS and
IRQ_AMIGA_EXTER) that are a combination of chained (for the CIA interrupt
controllers) and shared level interrupts (for motherboard hardware and
Zorro expansion
boards).
But irq_set_chained_handler() sets IRQ_NOREQUEST, i.e. the interrupt cannot
be requested anymore via request_irq(), so this rules out using it with shared
level interrupts.

What's the preferred way to handle this? Is there are standard way, or should I
write my own specialized irq_flow_handler_t that handles both?

In the old scheme, we just registered the chain handlers with
request_irq(), so they
worked nicely together with the shared level interrupts (cfr.
arch/m68k/amiga/cia.c)

Thanks!

Gr{oetje,eeting}s,

            Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
             Â Â -- Linus Torvalds
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