ARM: SMP: Always enable clock event broadcast support

The TWD local timers are unable to wake up the CPU when it is placed
into a low power mode, eg. C3.  Therefore, we need to adapt things
such that the TWD code can cope with this.

We do this by always providing a broadcast tick function, and marking
the fact that the TWD local timer will stop in low power modes.  This
means that when the CPU is placed into a low power mode, the core
timer code marks this fact, and allows an IPI to be given to the core.
Tested-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>

arch/arm/Kconfig

@@ -56,7 +56,7 @@ config GENERIC_CLOCKEVENTS
 config GENERIC_CLOCKEVENTS_BROADCAST
 	bool
 	depends on GENERIC_CLOCKEVENTS
-	default y if SMP && !LOCAL_TIMERS
+	default y if SMP
 
 config HAVE_TCM
 	bool

arch/arm/kernel/smp.c

@@ -429,7 +429,11 @@ static void smp_timer_broadcast(const struct cpumask *mask)
 {
 	send_ipi_message(mask, IPI_TIMER);
 }
+#else
+#define smp_timer_broadcast	NULL
+#endif
 
+#ifndef CONFIG_LOCAL_TIMERS
 static void broadcast_timer_set_mode(enum clock_event_mode mode,
 	struct clock_event_device *evt)
 {
@@ -444,7 +448,6 @@ static void local_timer_setup(struct clock_event_device *evt)
 	evt->rating	= 400;
 	evt->mult	= 1;
 	evt->set_mode	= broadcast_timer_set_mode;
-	evt->broadcast	= smp_timer_broadcast;
 
 	clockevents_register_device(evt);
 }
@@ -456,6 +459,7 @@ void __cpuinit percpu_timer_setup(void)
 	struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
 
 	evt->cpumask = cpumask_of(cpu);
+	evt->broadcast = smp_timer_broadcast;
 
 	local_timer_setup(evt);
 }

arch/arm/kernel/smp_twd.c

@@ -132,7 +132,8 @@ void __cpuinit twd_timer_setup(struct clock_event_device *clk)
 	twd_calibrate_rate();
 
 	clk->name = "local_timer";
-	clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+	clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
+			CLOCK_EVT_FEAT_C3STOP;
 	clk->rating = 350;
 	clk->set_mode = twd_set_mode;
 	clk->set_next_event = twd_set_next_event;