From mboxrd@z Thu Jan  1 00:00:00 1970
From: arnd@arndb.de (Arnd Bergmann)
Date: Fri, 03 Jan 2014 14:58:53 +0100
Subject: [PATCH v2 1/3] ARM: clps711x: Add CLPS711X irqchip driver
In-Reply-To: <1388755605.639174335@f136.i.mail.ru>
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 <201401031410.27374.arnd@arndb.de> <1388755605.639174335@f136.i.mail.ru>
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To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Friday 03 January 2014 17:26:45 Alexander Shiyan wrote:
> > > +   err = irq_alloc_descs(-1, 0, ARRAY_SIZE(clps711x_irqs), numa_node_id());
> > > +   if (IS_ERR_VALUE(err))
> > > +           goto out_iounmap;
> > > +
> > > +   clps711x_intc->ops.map = clps711x_intc_irq_map;
> > > +   clps711x_intc->ops.xlate = irq_domain_xlate_onecell;
> > > +   clps711x_intc->domain =
> > > +           irq_domain_add_legacy(np, ARRAY_SIZE(clps711x_irqs),
> > > +                                 0, 0, &clps711x_intc->ops, NULL);
> > 
> > Can't you use irq_domain_add_simple() here? When you are booting with DT
> > and SPARSE_IRQ, you should not need to allocate the descriptors at boot time,
> > but only as needed.
> > 
> > You will have to pass '0' as the first_irq argument for the DT case then,
> > and '1' for the non-DT case to actually allocate virqs starting at number 1.
> 
> Using irq_domain_add_simple() cause double usage of irq_alloc_descs(),
> so we cannot do it. At least now.

Well, the idea would be to remove the irq_alloc_descs() from your code,
and have irq_domain_add_simple() call it for the ATAGS case but not
at all for the DT case. That is exactly the purpose of '_simple', i.e.
to let the irq_alloc_descs() part be handled automatically if needed.
 
> PS: Arnd, can you merge this series for 3.14-rc within arm-soc?

I'd feel more comfortable if Thomas could have a look first and either
merge it himself or provide an Ack. I'm not much of an irqchip expert
and I don't want to step on his toes there.

	Arnd