powerpc: make irq_choose_cpu() available to all PIC drivers

Move irq_choose_cpu() into arch/powerpc/kernel/irq.c so that it can be used
by other PIC drivers.  The function is not MPIC-specific.

Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com>
Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 5b428e3..38dd10e 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -882,6 +882,41 @@
 }
 EXPORT_SYMBOL_GPL(irq_find_mapping);
 
+#ifdef CONFIG_SMP
+int irq_choose_cpu(const struct cpumask *mask)
+{
+	int cpuid;
+
+	if (cpumask_equal(mask, cpu_all_mask)) {
+		static int irq_rover;
+		static DEFINE_RAW_SPINLOCK(irq_rover_lock);
+		unsigned long flags;
+
+		/* Round-robin distribution... */
+do_round_robin:
+		raw_spin_lock_irqsave(&irq_rover_lock, flags);
+
+		irq_rover = cpumask_next(irq_rover, cpu_online_mask);
+		if (irq_rover >= nr_cpu_ids)
+			irq_rover = cpumask_first(cpu_online_mask);
+
+		cpuid = irq_rover;
+
+		raw_spin_unlock_irqrestore(&irq_rover_lock, flags);
+	} else {
+		cpuid = cpumask_first_and(mask, cpu_online_mask);
+		if (cpuid >= nr_cpu_ids)
+			goto do_round_robin;
+	}
+
+	return get_hard_smp_processor_id(cpuid);
+}
+#else
+int irq_choose_cpu(const struct cpumask *mask)
+{
+	return hard_smp_processor_id();
+}
+#endif
 
 unsigned int irq_radix_revmap_lookup(struct irq_host *host,
 				     irq_hw_number_t hwirq)