Re: [PATCH 2/4] irqdomain: augment add_simple() to allocate descs

From: Grant Likely
Date: Mon Nov 26 2012 - 16:34:18 EST


On Thu, 27 Sep 2012 08:41:53 -0500, Rob Herring <robherring2@xxxxxxxxx> wrote:
> On 09/27/2012 08:13 AM, Linus Walleij wrote:
> > ---
> > kernel/irq/irqdomain.c | 21 ++++++++++++++++-----
> > 1 file changed, 16 insertions(+), 5 deletions(-)
> >
> > diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
> > index 49a7772..a0655b6 100644
> > --- a/kernel/irq/irqdomain.c
> > +++ b/kernel/irq/irqdomain.c
> > @@ -148,7 +148,8 @@ static unsigned int irq_domain_legacy_revmap(struct irq_domain *domain,
> > * @host_data: Controller private data pointer
> > *
> > * Allocates a legacy irq_domain if irq_base is positive or a linear
> > - * domain otherwise.
> > + * domain otherwise. For the legacy domain, IRQ descriptors will also
> > + * be allocated.
> > *
> > * This is intended to implement the expected behaviour for most
> > * interrupt controllers which is that a linear mapping should
> > @@ -162,11 +163,21 @@ struct irq_domain *irq_domain_add_simple(struct device_node *of_node,
> > const struct irq_domain_ops *ops,
> > void *host_data)
> > {
> > - if (first_irq > 0)
> > - return irq_domain_add_legacy(of_node, size, first_irq, 0,
> > + if (first_irq > 0) {
> > + int irq_base;
> > +
> > + irq_base = irq_alloc_descs(first_irq, 0, size, numa_node_id());
>
> This will always fail for !SPARSE_IRQ, so we probably don't want warn in
> that case. So perhaps something like this:
>
> int irq_base = first_irq;
>
> if (is_enabled(CONFIG_SPARSE_IRQ)) {
> irq_base = irq_alloc_descs(first_irq, 0, size, numa_node_id());
> if (irq_base < 0) {
> WARN(1, "Cannot allocate irq_descs @ IRQ%d, assuming pre-allocated\n",
> first_irq);
> irq_base = first_irq;
> }
> }

Also, warn seems a little over-loud in this case. If the controller is
legitimately claiming irqs in the reserved range, then dumping out a
backtrace is kind of nasty.

g.
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