Commit-ID: 852db46d55e85b475a72e665ca08d3317769ceef
Gitweb: http://git.kernel.org/tip/852db46d55e85b475a72e665ca08d3317769ceef
Author: John Stultz <johnstul@xxxxxxxxxx>
AuthorDate: Tue, 13 Jul 2010 17:56:28 -0700
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 27 Jul 2010 12:40:55 +0200
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@xxxxxxxxxx>
LKML-Reference: <1279068988-21864-12-git-send-email-johnstul@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
include/linux/clocksource.h | 11 +++++++++++
kernel/time/clocksource.c | 29 ++++++++++++++++++++++++-----
2 files changed, 35 insertions(+), 5 deletions(-)
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 21677d9..c37b21a 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -292,6 +292,8 @@ clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec);
*/
extern int
__clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq);
+extern void
+__clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq);
static inline int clocksource_register_hz(struct clocksource *cs, u32 hz)
{
@@ -303,6 +305,15 @@ static inline int clocksource_register_khz(struct clocksource *cs, u32 khz)
return __clocksource_register_scale(cs, 1000, khz);
}
+static inline void __clocksource_updatefreq_hz(struct clocksource *cs, u32 hz)
+{
+ __clocksource_updatefreq_scale(cs, 1, hz);
+}
+
+static inline void __clocksource_updatefreq_khz(struct clocksource *cs, u32 khz)
+{
+ __clocksource_updatefreq_scale(cs, 1000, khz);
+}
static inline void
clocksource_calc_mult_shift(struct clocksource *cs, u32 freq, u32 minsec)
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index c543d21..c18d7ef 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();
--
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