Geert,
On Tue, 31 May 2011, Geert Uytterhoeven wrote:
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)
You still can setup all those handlers setup via request_irq() and
handle the demux part by calling generic_handle_irq() from the handler
which deals with that demux hardware. irq_set_chained_handler() is
merily an optimization which does not apply to potentially shared
primary interrupts.
Thanks,
tglx
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