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authorRussell King <rmk+kernel@arm.linux.org.uk>2010-12-20 14:28:02 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2010-12-20 15:09:16 +0000
commit10034aabca9032246762daaca3152f3e79380ea0 (patch)
tree32c0143b054ab6c5beeeb9726eaf86b87f2abd80
parente3d9c625f5e4158014e041f492b46e38ad10987e (diff)
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>
-rw-r--r--arch/arm/include/asm/localtimer.h12
-rw-r--r--arch/arm/include/asm/smp_twd.h1
-rw-r--r--arch/arm/kernel/smp.c19
-rw-r--r--arch/arm/kernel/smp_twd.c10
4 files changed, 18 insertions, 24 deletions
diff --git a/arch/arm/include/asm/localtimer.h b/arch/arm/include/asm/localtimer.h
index 50c7e7cfd67..6bc63ab498c 100644
--- a/arch/arm/include/asm/localtimer.h
+++ b/arch/arm/include/asm/localtimer.h
@@ -30,7 +30,6 @@ asmlinkage void do_local_timer(struct pt_regs *);
#include "smp_twd.h"
#define local_timer_ack() twd_timer_ack()
-#define local_timer_stop() twd_timer_stop()
#else
@@ -40,11 +39,6 @@ asmlinkage void do_local_timer(struct pt_regs *);
*/
int local_timer_ack(void);
-/*
- * Stop a local timer interrupt.
- */
-void local_timer_stop(void);
-
#endif
/*
@@ -52,12 +46,6 @@ void local_timer_stop(void);
*/
void local_timer_setup(struct clock_event_device *);
-#else
-
-static inline void local_timer_stop(void)
-{
-}
-
#endif
#endif
diff --git a/arch/arm/include/asm/smp_twd.h b/arch/arm/include/asm/smp_twd.h
index 634f357be6b..fed9981fba0 100644
--- a/arch/arm/include/asm/smp_twd.h
+++ b/arch/arm/include/asm/smp_twd.h
@@ -22,7 +22,6 @@ struct clock_event_device;
extern void __iomem *twd_base;
-void twd_timer_stop(void);
int twd_timer_ack(void);
void twd_timer_setup(struct clock_event_device *);
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 6afaf6f7306..4dc864ef9cd 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 35882fbf37f..24585d97c10 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