[ARM] 3946/1: AT91: at91_arch_reset and at91_extern_irq

The external interrupt sources are different on the various AT91
processors.  This patch introduces the global 'at91_extern_irq' variable
that contains a bitset of the available external interrupt sources.

The processor reset mechanism also differs on the various AT91
processors.  This patch also adds a global 'at91_arch_reset' callback
(from system.h) into the processor-specific code to perform the reset.

Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/include/asm-arm/arch-at91rm9200/system.h b/include/asm-arm/arch-at91rm9200/system.h
index 8a2ff47..1d54185 100644
--- a/include/asm-arm/arch-at91rm9200/system.h
+++ b/include/asm-arm/arch-at91rm9200/system.h
@@ -39,13 +39,15 @@
 	cpu_do_idle();
 }
 
+void (*at91_arch_reset)(void);
+
 static inline void arch_reset(char mode)
 {
-	/*
-	 * Perform a hardware reset with the use of the Watchdog timer.
-	 */
-	at91_sys_write(AT91_ST_WDMR, AT91_ST_RSTEN | AT91_ST_EXTEN | 1);
-	at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);
+	/* call the CPU-specific reset function */
+	if (at91_arch_reset)
+		(at91_arch_reset)();
+
+	for (;;) {}	/* wait fovever */
 }
 
 #define ARCH_ID_AT91RM9200	0x09200080