diff options
| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-12-20 15:28:02 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-12-20 16:09:16 +0100 |
| commit | 10034aabca9032246762daaca3152f3e79380ea0 (patch) | |
| tree | 32c0143b054ab6c5beeeb9726eaf86b87f2abd80 /arch/arm/kernel | |
| parent | ARM: CPU hotplug: fix hard-coded control register constants (diff) | |
| download | linux-10034aabca9032246762daaca3152f3e79380ea0.tar.xz linux-10034aabca9032246762daaca3152f3e79380ea0.zip | |
ARM: localtimer: clean up local timer on hot unplug
When a CPU is hot unplugged, the generic tick code cleans up the
clock event device, but fails to call down to the device's set_mode
function to actually shut the device down.
To work around this, we've historically had a local_timer_stop()
callback out of the hotplug code. However, this adds needless
complexity when we have the clock event device itself available.
Explicitly call the clock event device's set_mode function with
CLOCK_EVT_MODE_UNUSED, so that the hardware can be cleanly shutdown
without any special external callbacks. When/if the generic code
is fixed, percpu_timer_stop() can be killed off.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel')
| -rw-r--r-- | arch/arm/kernel/smp.c | 19 | ||||
| -rw-r--r-- | arch/arm/kernel/smp_twd.c | 10 |
2 files changed, 18 insertions, 11 deletions
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 6afaf6f73069..4dc864ef9cdf 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -189,6 +189,8 @@ int __cpuinit __cpu_up(unsigned int cpu) } #ifdef CONFIG_HOTPLUG_CPU +static void percpu_timer_stop(void); + /* * __cpu_disable runs on the processor to be shutdown. */ @@ -216,7 +218,7 @@ int __cpu_disable(void) /* * Stop the local timer for this CPU. */ - local_timer_stop(); + percpu_timer_stop(); /* * Flush user cache and TLB mappings, and then remove this CPU @@ -539,6 +541,21 @@ void __cpuinit percpu_timer_setup(void) local_timer_setup(evt); } +#ifdef CONFIG_HOTPLUG_CPU +/* + * The generic clock events code purposely does not stop the local timer + * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it + * manually here. + */ +static void percpu_timer_stop(void) +{ + unsigned int cpu = smp_processor_id(); + struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu); + + evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt); +} +#endif + static DEFINE_SPINLOCK(stop_lock); /* diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c index 35882fbf37f9..24585d97c104 100644 --- a/arch/arm/kernel/smp_twd.c +++ b/arch/arm/kernel/smp_twd.c @@ -150,13 +150,3 @@ void __cpuinit twd_timer_setup(struct clock_event_device *clk) clockevents_register_device(clk); } - -#ifdef CONFIG_HOTPLUG_CPU -/* - * take a local timer down - */ -void twd_timer_stop(void) -{ - __raw_writel(0, twd_base + TWD_TIMER_CONTROL); -} -#endif |