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authorMark Rutland <mark.rutland@arm.com>2013-01-14 17:05:22 +0000
committerThomas Gleixner <tglx@linutronix.de>2013-01-31 22:15:36 +0100
commit12ad10004645d38356b14d1fbba379c523a61916 (patch)
treefe8b798176191c681c6b2fa1c81aa55dc98568dc
parent12572dbb53638c6e454ef831c8fee7de3df24389 (diff)
clockevents: Add generic timer broadcast function
Currently, the timer broadcast mechanism is defined by a function pointer on struct clock_event_device. As the fundamental mechanism for broadcast is architecture-specific, this means that clock_event_device drivers cannot be shared across multiple architectures. This patch adds an (optional) architecture-specific function for timer tick broadcast, allowing drivers which may require broadcast functionality to be shared across multiple architectures. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: linux-arm-kernel@lists.infradead.org Cc: nico@linaro.org Cc: Will.Deacon@arm.com Cc: Marc.Zyngier@arm.com Cc: john.stultz@linaro.org Link: http://lkml.kernel.org/r/1358183124-28461-3-git-send-email-mark.rutland@arm.com Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--include/linux/clockchips.h5
-rw-r--r--kernel/time/Kconfig4
-rw-r--r--kernel/time/tick-broadcast.c13
3 files changed, 22 insertions, 0 deletions
diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h
index e1089aa7816d..66346521cb65 100644
--- a/include/linux/clockchips.h
+++ b/include/linux/clockchips.h
@@ -162,6 +162,11 @@ extern void clockevents_suspend(void);
extern void clockevents_resume(void);
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+#ifdef CONFIG_ARCH_HAS_TICK_BROADCAST
+extern void tick_broadcast(const struct cpumask *mask);
+#else
+#define tick_broadcast NULL
+#endif
extern int tick_receive_broadcast(void);
#endif
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index 8601f0db1261..b69692250af4 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -38,6 +38,10 @@ config GENERIC_CLOCKEVENTS_BUILD
default y
depends on GENERIC_CLOCKEVENTS
+# Architecture can handle broadcast in a driver-agnostic way
+config ARCH_HAS_TICK_BROADCAST
+ bool
+
# Clockevents broadcasting infrastructure
config GENERIC_CLOCKEVENTS_BROADCAST
bool
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 7cc81c57eb31..f726537d24eb 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -18,6 +18,7 @@
#include <linux/percpu.h>
#include <linux/profile.h>
#include <linux/sched.h>
+#include <linux/smp.h>
#include "tick-internal.h"
@@ -86,6 +87,11 @@ int tick_is_broadcast_device(struct clock_event_device *dev)
return (dev && tick_broadcast_device.evtdev == dev);
}
+static void err_broadcast(const struct cpumask *mask)
+{
+ pr_crit_once("Failed to broadcast timer tick. Some CPUs may be unresponsive.\n");
+}
+
/*
* Check, if the device is disfunctional and a place holder, which
* needs to be handled by the broadcast device.
@@ -105,6 +111,13 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
*/
if (!tick_device_is_functional(dev)) {
dev->event_handler = tick_handle_periodic;
+ if (!dev->broadcast)
+ dev->broadcast = tick_broadcast;
+ if (!dev->broadcast) {
+ pr_warn_once("%s depends on broadcast, but no broadcast function available\n",
+ dev->name);
+ dev->broadcast = err_broadcast;
+ }
cpumask_set_cpu(cpu, tick_get_broadcast_mask());
tick_broadcast_start_periodic(tick_broadcast_device.evtdev);
ret = 1;