irqchip/irq-csky-mpintc: Support auto irq deliver to all cpus

The csky,mpintc could deliver a external irq to one cpu or all cpus, but
it couldn't deliver a external irq to a group of cpus with cpu_mask. So
we only use auto deliver mode when affinity mask_val is equal to
cpu_present_mask.

There is no limitation for only two cpus in SMP system.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/irq-csky-mpintc.c

@@ -89,7 +89,18 @@ static int csky_irq_set_affinity(struct irq_data *d,
 	if (cpu >= nr_cpu_ids)
 		return -EINVAL;
 
-	/* Enable interrupt destination */
+	/*
+	 * The csky,mpintc could support auto irq deliver, but it only
+	 * could deliver external irq to one cpu or all cpus. So it
+	 * doesn't support deliver external irq to a group of cpus
+	 * with cpu_mask.
+	 * SO we only use auto deliver mode when affinity mask_val is
+	 * equal to cpu_present_mask.
+	 *
+	 */
+	if (cpumask_equal(mask_val, cpu_present_mask))
+		cpu = 0;
+	else
 		cpu |= BIT(31);
 
 	writel_relaxed(cpu, INTCG_base + INTCG_CIDSTR + offset);