irqchip/gic: Report that effective affinity is a single target

The GIC driver only targets a single CPU at a time, even if
the notional affinity is wider. Let's inform the core code
about this.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Wei Xu <xuwei5@hisilicon.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Gregory Clement <gregory.clement@free-electrons.com>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Link: http://lkml.kernel.org/r/20170818083925.10108-4-marc.zyngier@arm.com

drivers/irqchip/Kconfig

@@ -7,6 +7,7 @@ config ARM_GIC
 	select IRQ_DOMAIN
 	select IRQ_DOMAIN_HIERARCHY
 	select MULTI_IRQ_HANDLER
+	select GENERIC_IRQ_EFFECTIVE_AFF_MASK
 
 config ARM_GIC_PM
 	bool

drivers/irqchip/irq-gic.c

@@ -344,6 +344,8 @@ static int gic_set_affinity(struct irq_data *d, const struct cpumask *mask_val,
 	writel_relaxed(val | bit, reg);
 	gic_unlock_irqrestore(flags);
 
+	irq_data_update_effective_affinity(d, cpumask_of(cpu));
+
 	return IRQ_SET_MASK_OK_DONE;
 }
 #endif
@@ -966,6 +968,7 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq,
 		irq_domain_set_info(d, irq, hw, &gic->chip, d->host_data,
 				    handle_fasteoi_irq, NULL, NULL);
 		irq_set_probe(irq);
+		irqd_set_single_target(irq_desc_get_irq_data(irq_to_desc(irq)));
 	}
 	return 0;
 }