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authorJohn Stultz <johnstul@us.ibm.com>2010-07-13 17:56:28 -0700
committerThomas Gleixner <tglx@linutronix.de>2010-07-27 12:40:55 +0200
commit852db46d55e85b475a72e665ca08d3317769ceef (patch)
tree3802273b1135f0f650868fe9e048d7c0594195fe /kernel/time
parentf12a15be63d1de9a35971f35f06b73088fa25c3a (diff)
clocksource: Add __clocksource_updatefreq_hz/khz methods
To properly handle clocksources that change frequencies at the clocksource->enable() point, this patch adds a method that will update the clocksource's mult/shift and max_idle_ns values. Signed-off-by: John Stultz <johnstul@us.ibm.com> LKML-Reference: <1279068988-21864-12-git-send-email-johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/clocksource.c29
1 files changed, 24 insertions, 5 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index c543d21b4e54..c18d7efa1b4b 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -639,19 +639,18 @@ static void clocksource_enqueue(struct clocksource *cs)
#define MAX_UPDATE_LENGTH 5 /* Seconds */
/**
- * __clocksource_register_scale - Used to install new clocksources
+ * __clocksource_updatefreq_scale - Used update clocksource with new freq
* @t: clocksource to be registered
* @scale: Scale factor multiplied against freq to get clocksource hz
* @freq: clocksource frequency (cycles per second) divided by scale
*
- * Returns -EBUSY if registration fails, zero otherwise.
+ * This should only be called from the clocksource->enable() method.
*
* This *SHOULD NOT* be called directly! Please use the
- * clocksource_register_hz() or clocksource_register_khz helper functions.
+ * clocksource_updatefreq_hz() or clocksource_updatefreq_khz helper functions.
*/
-int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq)
+void __clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq)
{
-
/*
* Ideally we want to use some of the limits used in
* clocksource_max_deferment, to provide a more informed
@@ -662,7 +661,27 @@ int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq)
NSEC_PER_SEC/scale,
MAX_UPDATE_LENGTH*scale);
cs->max_idle_ns = clocksource_max_deferment(cs);
+}
+EXPORT_SYMBOL_GPL(__clocksource_updatefreq_scale);
+
+/**
+ * __clocksource_register_scale - Used to install new clocksources
+ * @t: clocksource to be registered
+ * @scale: Scale factor multiplied against freq to get clocksource hz
+ * @freq: clocksource frequency (cycles per second) divided by scale
+ *
+ * Returns -EBUSY if registration fails, zero otherwise.
+ *
+ * This *SHOULD NOT* be called directly! Please use the
+ * clocksource_register_hz() or clocksource_register_khz helper functions.
+ */
+int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq)
+{
+
+ /* Intialize mult/shift and max_idle_ns */
+ __clocksource_updatefreq_scale(cs, scale, freq);
+ /* Add clocksource to the clcoksource list */
mutex_lock(&clocksource_mutex);
clocksource_enqueue(cs);
clocksource_select();