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: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 7 insertions, 2 deletions

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index b8c3d0f689d9..0170e248a1dd 100644
--- a/arch/arm/kernel/smp.c
+++ b/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);
 }
diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c
index 7c5f0c024db7..35882fbf37f9 100644
--- a/arch/arm/kernel/smp_twd.c
+++ b/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;