irqchip: armada-370-xp: Add helper for the MSI IRQ handling

Introduce a helper function to handle the MSI interrupts. This makes
the code more readable. In addition, this will allow to introduce a
chained IRQ handler mechanism, which is needed in situations where the
MPIC is used as a slave to another interrupt controller.
Reviewed-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

drivers/irqchip/irq-armada-370-xp.c

@@ -352,29 +352,9 @@ static struct irq_domain_ops armada_370_xp_mpic_irq_ops = {
 	.xlate = irq_domain_xlate_onecell,
 };
 
-static asmlinkage void __exception_irq_entry
-armada_370_xp_handle_irq(struct pt_regs *regs)
-{
-	u32 irqstat, irqnr;
-
-	do {
-		irqstat = readl_relaxed(per_cpu_int_base +
-					ARMADA_370_XP_CPU_INTACK_OFFS);
-		irqnr = irqstat & 0x3FF;
-
-		if (irqnr > 1022)
-			break;
-
-		if (irqnr > 1) {
-			irqnr =	irq_find_mapping(armada_370_xp_mpic_domain,
-					irqnr);
-			handle_IRQ(irqnr, regs);
-			continue;
-		}
-
 #ifdef CONFIG_PCI_MSI
-		/* MSI handling */
-		if (irqnr == 1) {
+static void armada_370_xp_handle_msi_irq(struct pt_regs *regs)
+{
 	u32 msimask, msinr;
 
 	msimask = readl_relaxed(per_cpu_int_base +
@@ -395,9 +375,35 @@ armada_370_xp_handle_irq(struct pt_regs *regs)
 				       msinr - 16);
 		handle_IRQ(irq, regs);
 	}
-		}
+}
+#else
+static void armada_370_xp_handle_msi_irq(struct pt_regs *r) {}
 #endif
 
+static asmlinkage void __exception_irq_entry
+armada_370_xp_handle_irq(struct pt_regs *regs)
+{
+	u32 irqstat, irqnr;
+
+	do {
+		irqstat = readl_relaxed(per_cpu_int_base +
+					ARMADA_370_XP_CPU_INTACK_OFFS);
+		irqnr = irqstat & 0x3FF;
+
+		if (irqnr > 1022)
+			break;
+
+		if (irqnr > 1) {
+			irqnr =	irq_find_mapping(armada_370_xp_mpic_domain,
+					irqnr);
+			handle_IRQ(irqnr, regs);
+			continue;
+		}
+
+		/* MSI handling */
+		if (irqnr == 1)
+			armada_370_xp_handle_msi_irq(regs);
+
 #ifdef CONFIG_SMP
 		/* IPI Handling */
 		if (irqnr == 0) {