powerpc/powernv: Separate function for OPAL IRQ setup

The patch put the OPAL interrupt setup logic in opal_init() into
seperate function opal_irq_init() for easier code maintaining. The
patch doesn't introduce logic changes except:

   * Rename variable names.
   * Release virtual IRQ upon error from request_irq().
   * Don't cache the virtual IRQ to opal_irqs[] upon error from
     request_irq().

Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/powernv/opal.c

@@ -701,11 +701,49 @@ static void opal_i2c_create_devs(void)
 		of_platform_device_create(np, NULL, NULL);
 }
 
+static void __init opal_irq_init(struct device_node *dn)
+{
+	const __be32 *irqs;
+	int i, irqlen;
+
+	/* Get interrupt property */
+	irqs = of_get_property(opal_node, "opal-interrupts", &irqlen);
+	pr_debug("Found %d interrupts reserved for OPAL\n",
+		 irqs ? (irqlen / 4) : 0);
+
+	/* Install interrupt handlers */
+	opal_irq_count = irqlen / 4;
+	opal_irqs = kzalloc(opal_irq_count * sizeof(unsigned int), GFP_KERNEL);
+	for (i = 0; irqs && i < opal_irq_count; i++, irqs++) {
+		unsigned int irq, virq;
+		int rc;
+
+		/* Get hardware and virtual IRQ */
+		irq = be32_to_cpup(irqs);
+		virq = irq_create_mapping(NULL, irq);
+		if (virq == NO_IRQ) {
+			pr_warn("Failed to map irq 0x%x\n", irq);
+			continue;
+		}
+
+		/* Install interrupt handler */
+		rc = request_irq(virq, opal_interrupt, 0, "opal", NULL);
+		if (rc) {
+			irq_dispose_mapping(virq);
+			pr_warn("Error %d requesting irq %d (0x%x)\n",
+				 rc, virq, irq);
+			continue;
+		}
+
+		/* Cache IRQ */
+		opal_irqs[i] = virq;
+	}
+}
+
 static int __init opal_init(void)
 {
 	struct device_node *np, *consoles;
-	const __be32 *irqs;
-	int rc, i, irqlen;
+	int rc;
 
 	opal_node = of_find_node_by_path("/ibm,opal");
 	if (!opal_node) {
@@ -731,24 +769,7 @@ static int __init opal_init(void)
 	opal_i2c_create_devs();
 
 	/* Find all OPAL interrupts and request them */
-	irqs = of_get_property(opal_node, "opal-interrupts", &irqlen);
-	pr_debug("Found %d interrupts reserved for OPAL\n",
-		 irqs ? (irqlen / 4) : 0);
-	opal_irq_count = irqlen / 4;
-	opal_irqs = kzalloc(opal_irq_count * sizeof(unsigned int), GFP_KERNEL);
-	for (i = 0; irqs && i < (irqlen / 4); i++, irqs++) {
-		unsigned int hwirq = be32_to_cpup(irqs);
-		unsigned int irq = irq_create_mapping(NULL, hwirq);
-		if (irq == NO_IRQ) {
-			pr_warning("Failed to map irq 0x%x\n", hwirq);
-			continue;
-		}
-		rc = request_irq(irq, opal_interrupt, 0, "opal", NULL);
-		if (rc)
-			pr_warning("Error %d requesting irq %d (0x%x)\n",
-				    rc, irq, hwirq);
-		opal_irqs[i] = irq;
-	}
+	opal_irq_init(opal_node);
 
 	/* Create "opal" kobject under /sys/firmware */
 	rc = opal_sysfs_init();