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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>
This commit is contained in:
Russell King 2010-07-26 13:19:43 +01:00
parent 9ca03a21e3
commit 5388a6b266
3 changed files with 8 additions and 3 deletions
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2
arch/arm/Kconfig
View File

@ -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

6
arch/arm/kernel/smp.c
View File

@ -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);
}

3
arch/arm/kernel/smp_twd.c
View File

@ -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;