Re: irq consolidation

From: Andrey Panin (
Date: Mon Jun 16 2003 - 07:09:12 EST

On 163, 06 12, 2003 at 09:34:06PM +1000, Anton Blanchard wrote:
> > I believe Andrey's IRQ consolidation provides a single flat IRQ
> > structure. Unfortunately, this doesn't reflect the reality that we
> > have on many ARM platforms - it remains the case that we need to
> > decode IRQs on a multi-level basis.
> Yes its still a flat structure. On ppc32/64 we offset the interrupts on
> the main controller to provide a space for ISA interrupts to go. Not
> great but it works for us.

May be I missed the point, but it isn't flat.

You can define HAVE_ARCH_IRQ_DESC and provide your own irq_desc(irq)
function which will translate irq number to the corresponding
irq_desc_t structure. You are free to implement any irq mappings
behind the irq_desc(). NR_IRQS is used only as maximal irq number.
So what is the problem ?
> One thing Paul suggested was to have a flag to mark an interrupt as a
> cascade in the irq descriptor. If its set then we also provide a
> get_irq() method (perhaps stashed away in the ->action field). That gives
> us nested interrupt handling in generic code. (assuming you can
> partition your irq numbers somehow)
> Anton

Andrey Panin		| Linux and UNIX system administrator		| PGP key:

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