sh: dyntick infrastructure.

This adds basic NO_IDLE_HZ support to the SH timer API so timers
are able to wire it up. Taken from the ARM version, as it fit in
to our API with very few changes needed.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/include/asm-sh/timer.h b/include/asm-sh/timer.h
index 5a014bc..17b5e76 100644
--- a/include/asm-sh/timer.h
+++ b/include/asm-sh/timer.h
@@ -18,8 +18,29 @@
 
 	struct sys_device	dev;
 	struct sys_timer_ops	*ops;
+
+#ifdef CONFIG_NO_IDLE_HZ
+	struct dyn_tick_timer	*dyn_tick;
+#endif
 };
 
+#ifdef CONFIG_NO_IDLE_HZ
+#define DYN_TICK_ENABLED	(1 << 1)
+
+struct dyn_tick_timer {
+	spinlock_t	lock;
+	unsigned int	state;			/* Current state */
+	int		(*enable)(void);	/* Enables dynamic tick */
+	int		(*disable)(void);	/* Disables dynamic tick */
+	void		(*reprogram)(unsigned long); /* Reprograms the timer */
+	int		(*handler)(int, void *);
+};
+
+void timer_dyn_reprogram(void);
+#else
+#define timer_dyn_reprogram()	do { } while (0)
+#endif
+
 #define TICK_SIZE (tick_nsec / 1000)
 
 extern struct sys_timer tmu_timer, cmt_timer, mtu2_timer;