summaryrefslogtreecommitdiff
path: root/kernel/time/time.c
diff options
context:
space:
mode:
authorJohn Stultz <john.stultz@linaro.org>2014-07-16 21:03:59 +0000
committerJohn Stultz <john.stultz@linaro.org>2014-07-23 10:17:53 -0700
commit49cd6f869984692547c57621bf42697aaa7f5622 (patch)
treef0bb760b91afa73f12f6f90db14b190728c0780b /kernel/time/time.c
parent361a3bf00582469877f8d18ff20f1efa6b781274 (diff)
time: More core infrastructure for timespec64
Helper and conversion functions for timespec64. Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
Diffstat (limited to 'kernel/time/time.c')
-rw-r--r--kernel/time/time.c62
1 files changed, 62 insertions, 0 deletions
diff --git a/kernel/time/time.c b/kernel/time/time.c
index 7c7964c33ae7..e8121a67fd74 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -420,6 +420,68 @@ struct timeval ns_to_timeval(const s64 nsec)
}
EXPORT_SYMBOL(ns_to_timeval);
+#if BITS_PER_LONG == 32
+/**
+ * set_normalized_timespec - set timespec sec and nsec parts and normalize
+ *
+ * @ts: pointer to timespec variable to be set
+ * @sec: seconds to set
+ * @nsec: nanoseconds to set
+ *
+ * Set seconds and nanoseconds field of a timespec variable and
+ * normalize to the timespec storage format
+ *
+ * Note: The tv_nsec part is always in the range of
+ * 0 <= tv_nsec < NSEC_PER_SEC
+ * For negative values only the tv_sec field is negative !
+ */
+void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec)
+{
+ while (nsec >= NSEC_PER_SEC) {
+ /*
+ * The following asm() prevents the compiler from
+ * optimising this loop into a modulo operation. See
+ * also __iter_div_u64_rem() in include/linux/time.h
+ */
+ asm("" : "+rm"(nsec));
+ nsec -= NSEC_PER_SEC;
+ ++sec;
+ }
+ while (nsec < 0) {
+ asm("" : "+rm"(nsec));
+ nsec += NSEC_PER_SEC;
+ --sec;
+ }
+ ts->tv_sec = sec;
+ ts->tv_nsec = nsec;
+}
+EXPORT_SYMBOL(set_normalized_timespec64);
+
+/**
+ * ns_to_timespec64 - Convert nanoseconds to timespec64
+ * @nsec: the nanoseconds value to be converted
+ *
+ * Returns the timespec64 representation of the nsec parameter.
+ */
+struct timespec64 ns_to_timespec64(const s64 nsec)
+{
+ struct timespec64 ts;
+ s32 rem;
+
+ if (!nsec)
+ return (struct timespec64) {0, 0};
+
+ ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem);
+ if (unlikely(rem < 0)) {
+ ts.tv_sec--;
+ rem += NSEC_PER_SEC;
+ }
+ ts.tv_nsec = rem;
+
+ return ts;
+}
+EXPORT_SYMBOL(ns_to_timespec64);
+#endif
/*
* When we convert to jiffies then we interpret incoming values
* the following way: