Re: [RFC PATCH 2/5] clockevents: Add generic timer broadcast receiver

From: Santosh Shilimkar
Date: Fri Dec 21 2012 - 05:02:02 EST


On Tuesday 18 December 2012 05:36 PM, Mark Rutland wrote:
Currently the broadcast mechanism used for timers is abstracted by a
function pointer on struct clock_event_device. As the fundamental
mechanism for broadcast is architecture-specific, this ties each
clock_event_device driver to a single architecture, even where the
driver is otherwise generic.

This patch adds a standard path for the receipt of timer broadcasts, so
drivers and/or architecture backends need not manage redundant lists of
timers for the purpose of routing broadcast timer ticks.

Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
---
include/linux/clockchips.h | 4 ++++
kernel/time/tick-broadcast.c | 15 +++++++++++++++
2 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h
index 8a7096f..e1089aa 100644
--- a/include/linux/clockchips.h
+++ b/include/linux/clockchips.h
@@ -161,6 +161,10 @@ clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec)
extern void clockevents_suspend(void);
extern void clockevents_resume(void);

+#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+extern int tick_receive_broadcast(void);
+#endif
+
As mentioned in earlier patch, CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
isn't must for SMP kernel and hence when build with
!GENERIC_CLOCKEVENTS_BROADCAST, $subject patch will break the build.

Below is the fix for the same. Feel free to fold it if you agree.

diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h
index 6634652..921568b 100644
--- a/include/linux/clockchips.h
+++ b/include/linux/clockchips.h
@@ -168,6 +168,11 @@ extern void tick_broadcast(const struct cpumask *mask);
#define tick_broadcast NULL
#endif
extern int tick_receive_broadcast(void);
+#else
+static inline int tick_receive_broadcast(void)
+{
+ return 0;
+}
#endif

#ifdef CONFIG_GENERIC_CLOCKEVENTS

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