ARM: GIC: Add global gic_handle_irq() function

Provide the GIC code with a low level handler that can be used
by platforms using CONFIG_MULTI_IRQ_HANDLER.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

arch/arm/common/gic.c

@@ -40,6 +40,7 @@
 #include <linux/slab.h>
 
 #include <asm/irq.h>
+#include <asm/exception.h>
 #include <asm/mach/irq.h>
 #include <asm/hardware/gic.h>
 
@@ -272,6 +273,32 @@ static int gic_set_wake(struct irq_data *d, unsigned int on)
 #define gic_set_wake	NULL
 #endif
 
+asmlinkage void __exception_irq_entry gic_handle_irq(struct pt_regs *regs)
+{
+	u32 irqstat, irqnr;
+	struct gic_chip_data *gic = &gic_data[0];
+	void __iomem *cpu_base = gic_data_cpu_base(gic);
+
+	do {
+		irqstat = readl_relaxed(cpu_base + GIC_CPU_INTACK);
+		irqnr = irqstat & ~0x1c00;
+
+		if (likely(irqnr > 15 && irqnr < 1021)) {
+			irqnr = irq_domain_to_irq(&gic->domain, irqnr);
+			handle_IRQ(irqnr, regs);
+			continue;
+		}
+		if (irqnr < 16) {
+			writel_relaxed(irqstat, cpu_base + GIC_CPU_EOI);
+#ifdef CONFIG_SMP
+			handle_IPI(irqnr, regs);
+#endif
+			continue;
+		}
+		break;
+	} while (1);
+}
+
 static void gic_handle_cascade_irq(unsigned int irq, struct irq_desc *desc)
 {
 	struct gic_chip_data *chip_data = irq_get_handler_data(irq);