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authorjohn stultz <johnstul@us.ibm.com>2009-05-01 16:10:26 -0400
committerThomas Gleixner <tglx@linutronix.de>2009-05-02 05:45:15 -0400
commit7d27558c4138ac6b3684dea35c2f4379b940a7dd (patch)
treec10f5cee4dda1e6bc7977d016db020377f97feab /include
parenta25cbd045a2ffc42787d4dbcbb9c7118f5f42732 (diff)
timekeeping: create arch_gettimeoffset infrastructure
Some arches don't supply their own clocksource. This is mainly the case in architectures that get their inter-tick times by reading the counter on their interval timer. Since these timers wrap every tick, they're not really useful as clocksources. Wrapping them to act like one is possible but not very efficient. So we provide a callout these arches can implement for use with the jiffies clocksource to provide finer then tick granular time. [ Impact: ease the migration to generic time keeping ] Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include')
-rw-r--r--include/linux/time.h15
1 files changed, 15 insertions, 0 deletions
diff --git a/include/linux/time.h b/include/linux/time.h
index 242f62499bb7..ea16c1a01d51 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -113,6 +113,21 @@ struct timespec current_kernel_time(void);
113#define CURRENT_TIME (current_kernel_time()) 113#define CURRENT_TIME (current_kernel_time())
114#define CURRENT_TIME_SEC ((struct timespec) { get_seconds(), 0 }) 114#define CURRENT_TIME_SEC ((struct timespec) { get_seconds(), 0 })
115 115
116/* Some architectures do not supply their own clocksource.
117 * This is mainly the case in architectures that get their
118 * inter-tick times by reading the counter on their interval
119 * timer. Since these timers wrap every tick, they're not really
120 * useful as clocksources. Wrapping them to act like one is possible
121 * but not very efficient. So we provide a callout these arches
122 * can implement for use with the jiffies clocksource to provide
123 * finer then tick granular time.
124 */
125#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
126extern u32 arch_gettimeoffset(void);
127#else
128static inline u32 arch_gettimeoffset(void) { return 0; }
129#endif
130
116extern void do_gettimeofday(struct timeval *tv); 131extern void do_gettimeofday(struct timeval *tv);
117extern int do_settimeofday(struct timespec *tv); 132extern int do_settimeofday(struct timespec *tv);
118extern int do_sys_settimeofday(struct timespec *tv, struct timezone *tz); 133extern int do_sys_settimeofday(struct timespec *tv, struct timezone *tz);