irqchip/gic: Allow self-SGIs for SMP on UP configurations
On systems where a single CPU is present, the GIC may not support
having SGIs delivered to a target list. In that case, we use the
self-SGI mechanism to allow the interrupt to be delivered locally.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index c2cab57..390fac5 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -769,6 +769,13 @@
int cpu;
unsigned long flags, map = 0;
+ if (unlikely(nr_cpu_ids == 1)) {
+ /* Only one CPU? let's do a self-IPI... */
+ writel_relaxed(2 << 24 | irq,
+ gic_data_dist_base(&gic_data[0]) + GIC_DIST_SOFTINT);
+ return;
+ }
+
raw_spin_lock_irqsave(&irq_controller_lock, flags);
/* Convert our logical CPU mask into a physical one. */
