Re: [PATCH v4 2/5] irqchip: add virtual demultiplexer implementation

Boris Brezillon
2015-02-10T15:20:17Z

Hello Peter,

On Tue, 10 Feb 2015 16:00:13 +0100
Peter Zijlstra <peterz@infradead.org> wrote:

> On Thu, Jan 29, 2015 at 11:33:37AM +0100, Boris Brezillon wrote:
> > +#ifdef CONFIG_VIRT_IRQ_DEMUX_CHIP
> > +/**
> > + * struct irq_chip_virt_demux - Dumb demultiplexer irq chip data structure
>
> s/Dumb/Virtual/ ?
>
> > + * @domain: irq domain pointer
> > + * @available: Bitfield of valid irqs
> > + * @unmasked: Bitfield containing irqs status
> > + * @flags: irq_virt_demux_flags flags
> > + * @src_irq: irq feeding the virt demux chip
> > + *
> > + * Note, that irq_chip_generic can have multiple irq_chip_type
> > + * implementations which can be associated to a particular irq line of
> > + * an irq_chip_generic instance. That allows to share and protect
> > + * state in an irq_chip_generic instance when we need to implement
> > + * different flow mechanisms (level/edge) for it.
>
> This seems like a copy/paste from struct irq_chip_generic; it seems not
> relevant, seeing how irq_chip_virt_demux does not even have an
> irq_chip_type pointer list.
>
> Also, with a demuxer like this, we're bound to whatever flow type its
> host is, no?

Absolutely, I'll fix the comment by removing those lines.

>
> > +# Dumb interrupt demuxer chip implementation
>
> s/Dumb/Virtual/ ?

Yep, I'll fix that one too.

>
> > +#ifdef CONFIG_VIRT_IRQ_DEMUX_CHIP
> > +/**
> > + * handle_virt_demux_irq - Dumb demuxer irq handle function.
>
> idem
>
> > + * @irq: the interrupt number
> > + * @desc: the interrupt description structure for this irq
> > + *
> > + * Dumb demux interrupts are sent from a demultiplexing interrupt handler
>
> idem
>
> > + * which is not able to decide which child interrupt handler should be
> > + * called.
> > + *
> > + * Note: The caller is expected to handle the ack, clear, mask and
> > + * unmask issues if necessary.
> > + */
>
> If we're calling multiple handlers, how can they all do this and not
> collide?

It's the same problem as you noted above: a copy/paste that should have
been reworded.
I'll remove those lines too.

>
> Over all it looks good -- in as far as my (admittedly stale IRQ
> braincells) go.
>
> I'll go queue up these bits, if you could send me a delta patch
> addressing these 'minor' comment issues?

Thanks, I'll send you a patch addressing your comments (it would be
great if you could squash it with this patch).

Regards,

Boris

--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering