[RFC PATCH] irqchip: add dumb demultiplexer implementation

[tglx@linutronix.de (Thomas Gleixner)]

On Tue, 13 Jan 2015, Boris Brezillon wrote:
> On Tue, 13 Jan 2015 11:38:14 +0100 (CET)
> Thomas Gleixner <tglx@linutronix.de> wrote:
> > 
> > > +/**
> > > + *	handle_dumb_demux_irq - Dumb demuxer irq handle function.
> > > + *	@irq:	the interrupt number
> > > + *	@desc:	the interrupt description structure for this irq
> > > + *
> > > + *	Dumb demux interrupts are sent from a demultiplexing interrupt handler
> > > + *	which is not able to decide which child interrupt interrupt handler
> > > + *	should be called.
> > > + *
> > > + *	Note: The caller is expected to handle the ack, clear, mask and
> > > + *	unmask issues if necessary.
> > > + */
> > > +irqreturn_t
> > > +handle_dumb_demux_irq(unsigned int irq, struct irq_desc *desc)
> > > +{
> > > +	irqreturn_t retval = IRQ_NONE;
> > > +
> > > +	raw_spin_lock(&desc->lock);
> > > +
> > > +	if (!irq_may_run(desc))
> > > +		goto out_unlock;
> > > +
> > > +	desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
> > > +	kstat_incr_irqs_this_cpu(irq, desc);
> > > +
> > > +	if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
> > > +		desc->istate |= IRQS_PENDING;
> > > +		goto out_unlock;
> > > +	}
> > > +
> > > +	retval = handle_irq_event_no_spurious_check(desc);
> > > +
> > > +out_unlock:
> > > +	raw_spin_unlock(&desc->lock);
> > > +
> > > +	return retval;
> > > +}
> > > +EXPORT_SYMBOL_GPL(handle_dumb_demux_irq);
> > 
> > This should go into the new file as well, so it gets compiled out when
> > not enabled.
> 
> Actually, I can't move that function out of kernel/irq/chip.c because
> it calls irq_may_run which is statically defined in this file.
> Should I export this function or just enclose it in a
> #ifdef DUMB_IRQ_DEMUX section ?

Missed that. Make it conditional then.