Re: [PATCH v2 6/9] irqchip / gic: Add stacked irqdomain support for ACPI based GICv2 init

From: Lorenzo Pieralisi
Date: Tue Jun 23 2015 - 13:38:36 EST


On Tue, Jun 23, 2015 at 04:11:38PM +0100, Hanjun Guo wrote:

[...]

> >> diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
> >> index 8fc67bc..d1b2131 100644
> >> --- a/drivers/irqchip/irq-gic.c
> >> +++ b/drivers/irqchip/irq-gic.c
> >> @@ -851,15 +851,22 @@ static struct notifier_block gic_cpu_notifier = {
> >> static int gic_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
> >> unsigned int nr_irqs, void *arg)
> >> {
> >> - int i, ret;
> >> + int i;
> >> irq_hw_number_t hwirq;
> >> - unsigned int type = IRQ_TYPE_NONE;
> >> - struct of_phandle_args *irq_data = arg;
> >>
> >> - ret = gic_irq_domain_xlate(domain, irq_data->np, irq_data->args,
> >> - irq_data->args_count, &hwirq, &type);
> >> - if (ret)
> >> - return ret;
> >> + if (domain->of_node) { /* DT case */
> >> + int ret;
> >> + unsigned int type = IRQ_TYPE_NONE;
> >> + struct of_phandle_args *irq_data = arg;
> >> +
> >> + ret = gic_irq_domain_xlate(domain, irq_data->np,
> >> + irq_data->args,
> >> + irq_data->args_count, &hwirq, &type);
> >> + if (ret)
> >> + return ret;
> >> + } else { /* ACPI case */
> >> + hwirq = (irq_hw_number_t)*(u32 *)arg;
> >> + }
> >
> > If domain->of_node is NULL and system booted with DT the code above
> > does not fail (and if it fails almost certainly that won't be graceful)
> > but it should.
>
> how about the following logic?
>
> if (!domain->of_node && acpi_disabled)
> return -ENODEV;
> else if (domain->of_node)
> dt related code;
> else
> ACPI related code;

Code is not checking the node at present so:

if (acpi_disabled)
dt code;
else
ACPI code;

would do, but that's a nit.

> >> for (i = 0; i < nr_irqs; i++)
> >> gic_irq_domain_map(domain, virq + i, hwirq + i);
> >> @@ -945,11 +952,11 @@ void __init gic_init_bases(unsigned int gic_nr, int irq_start,
> >> gic_irqs = 1020;
> >> gic->gic_irqs = gic_irqs;
> >>
> >> - if (node) { /* DT case */
> >> + if (node || !acpi_disabled) { /* DT or ACPI case */
> >> gic->domain = irq_domain_add_linear(node, gic_irqs,
> >> &gic_irq_domain_hierarchy_ops,
> >> gic);

I think this is a bit more worrying, I mean passing a NULL node pointer to
the irqdomain layer which basically means you are booting out of ACPI
(for you, if that's true for the irq_domain_add_linear implementation
that's another story), the node pointer should be optional but you
need feedback from IRQ layer maintainers here.

Lorenzo
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