C6X: remove megamod-pic requirement on direct-mapped core pic

The megamodule PIC cascades a number of interrupt sources into the core
priority PIC. The megamodule code depends on the core hardware interrupt
numbers being mapped one-to-one with regard to linux interrupt numbers.
This patch removes that dependence in order to pave the way for removing
the direct mapping in the core PIC code.
Signed-off-by: Mark Salter <msalter@redhat.com>

arch/c6x/platforms/megamod-pic.c

@@ -243,27 +243,37 @@ static struct megamod_pic * __init init_megamod_pic(struct device_node *np)
 	 * as their interrupt parent.
 	 */
 	for (i = 0; i < NR_COMBINERS; i++) {
+		struct irq_data *irq_data;
+		irq_hw_number_t hwirq;
 
 		irq = irq_of_parse_and_map(np, i);
 		if (irq == NO_IRQ)
 			continue;
 
+		irq_data = irq_get_irq_data(irq);
+		if (!irq_data) {
+			pr_err("%s: combiner-%d no irq_data for virq %d!\n",
+			       np->full_name, i, irq);
+			continue;
+		}
+
+		hwirq = irq_data->hwirq;
+
 		/*
-		 * We count on the core priority interrupts (4 - 15) being
-		 * direct mapped. Check that device tree provided something
-		 * in that range.
+		 * Check that device tree provided something in the range
+		 * of the core priority interrupts (4 - 15).
 		 */
-		if (irq < 4 || irq >= NR_PRIORITY_IRQS) {
-			pr_err("%s: combiner-%d virq %d out of range!\n",
-				 np->full_name, i, irq);
+		if (hwirq < 4 || hwirq >= NR_PRIORITY_IRQS) {
+			pr_err("%s: combiner-%d core irq %ld out of range!\n",
+			       np->full_name, i, hwirq);
 			continue;
 		}
 
 		/* record the mapping */
-		mapping[irq - 4] = i;
+		mapping[hwirq - 4] = i;
 
-		pr_debug("%s: combiner-%d cascading to virq %d\n",
-			 np->full_name, i, irq);
+		pr_debug("%s: combiner-%d cascading to hwirq %ld\n",
+			 np->full_name, i, hwirq);
 
 		cascade_data[i].pic = pic;
 		cascade_data[i].index = i;