irqchip/metag-ext: Report that effective affinity is a single target

The metag-ext 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/20170818083925.10108-10-marc.zyngier@arm.com

arch/metag/Kconfig

@@ -26,6 +26,7 @@ config METAG
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_UNDERSCORE_SYMBOL_PREFIX
 	select IRQ_DOMAIN
+	select GENERIC_IRQ_EFFECTIVE_AFF_MASK
 	select MODULES_USE_ELF_RELA
 	select OF
 	select OF_EARLY_FLATTREE

drivers/irqchip/irq-metag-ext.c

@@ -518,6 +518,8 @@ static int meta_intc_set_affinity(struct irq_data *data,
 
 	metag_out32(TBI_TRIG_VEC(TBID_SIGNUM_TR2(thread)), vec_addr);
 
+	irq_data_update_effective_affinity(data, cpumask_of(cpu));
+
 	return 0;
 }
 #else
@@ -578,6 +580,8 @@ static int meta_intc_map(struct irq_domain *d, unsigned int irq,
 	else
 		irq_set_chip_and_handler(irq, &meta_intc_edge_chip,
 					 handle_edge_irq);
+
+	irqd_set_single_target(irq_desc_get_irq_data(irq_to_desc(irq)));
 	return 0;
 }