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Commit 5388a6b2 authored by Russell King's avatar Russell King
Browse files

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: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
parent 9ca03a21

arch/arm/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -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

+5 −1
Original line number Diff line number Diff line
@@ -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

+2 −1
Original line number Diff line number Diff line
@@ -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;