arm64: Use irqchip_init() for interrupt controller initialisation

This patch uses the generic irqchip_init() function for initialising the
interrupt controller on arm64. It also adds several definitions required
by the ARM GIC irqchip driver but does not enable ARM_GIC yet.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/include/asm/exception.h

@@ -19,5 +19,6 @@
 #define __ASM_EXCEPTION_H
 
 #define __exception	__attribute__((section(".exception.text")))
+#define __exception_irq_entry	__exception
 
 #endif	/* __ASM_EXCEPTION_H */

arch/arm64/include/asm/hardirq.h

@@ -49,4 +49,9 @@ static inline void ack_bad_irq(unsigned int irq)
 
 extern void handle_IRQ(unsigned int, struct pt_regs *);
 
+/*
+ * No arch-specific IRQ flags.
+ */
+#define set_irq_flags(irq, flags)
+
 #endif /* __ASM_HARDIRQ_H */

arch/arm64/include/asm/irq.h

@@ -4,5 +4,6 @@
 #include <asm-generic/irq.h>
 
 extern void (*handle_arch_irq)(struct pt_regs *);
+extern void set_handle_irq(void (*handle_irq)(struct pt_regs *));
 
 #endif

arch/arm64/kernel/irq.c

@@ -25,7 +25,7 @@
 #include <linux/irq.h>
 #include <linux/smp.h>
 #include <linux/init.h>
-#include <linux/of_irq.h>
+#include <linux/irqchip.h>
 #include <linux/seq_file.h>
 #include <linux/ratelimit.h>
 
@@ -67,18 +67,17 @@ void handle_IRQ(unsigned int irq, struct pt_regs *regs)
 	set_irq_regs(old_regs);
 }
 
-/*
- * Interrupt controllers supported by the kernel.
- */
-static const struct of_device_id intctrl_of_match[] __initconst = {
-	/* IRQ controllers { .compatible, .data } info to go here */
-	{}
-};
+void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
+{
+	if (handle_arch_irq)
+		return;
+
+	handle_arch_irq = handle_irq;
+}
 
 void __init init_IRQ(void)
 {
-	of_irq_init(intctrl_of_match);
-
+	irqchip_init();
 	if (!handle_arch_irq)
 		panic("No interrupt controller found.");
 }