genirq: Add generic_handle_domain_irq() helper

Provide generic_handle_domain_irq() as a pendent to handle_domain_irq()
for non-root interrupt controllers
Signed-off-by: Marc Zyngier <maz@kernel.org>

include/linux/irqdesc.h

@@ -170,6 +170,8 @@ int generic_handle_irq(unsigned int irq);
 int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq,
 			bool lookup, struct pt_regs *regs);
 
+int generic_handle_domain_irq(struct irq_domain *domain, unsigned int hwirq);
+
 static inline int handle_domain_irq(struct irq_domain *domain,
 				    unsigned int hwirq, struct pt_regs *regs)
 {

kernel/irq/irqdesc.c

@@ -661,7 +661,24 @@ EXPORT_SYMBOL_GPL(generic_handle_irq);
 
 #ifdef CONFIG_HANDLE_DOMAIN_IRQ
 /**
- * __handle_domain_irq - Invoke the handler for a HW irq belonging to a domain
+ * generic_handle_domain_irq - Invoke the handler for a HW irq belonging
+ *                             to a domain, usually for a non-root interrupt
+ *                             controller
+ * @domain:	The domain where to perform the lookup
+ * @hwirq:	The HW irq number to convert to a logical one
+ *
+ * Returns:	0 on success, or -EINVAL if conversion has failed
+ *
+ */
+int generic_handle_domain_irq(struct irq_domain *domain, unsigned int hwirq)
+{
+	return handle_irq_desc(irq_resolve_mapping(domain, hwirq));
+}
+EXPORT_SYMBOL_GPL(generic_handle_domain_irq);
+
+/**
+ * __handle_domain_irq - Invoke the handler for a HW irq belonging to a domain,
+ *                       usually for a root interrupt controller
  * @domain:	The domain where to perform the lookup
  * @hwirq:	The HW irq number to convert to a logical one
  * @lookup:	Whether to perform the domain lookup or not