From 0077dc60f274b9a7e9aa705a34784fefb87e0eee Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 16 Jul 2014 21:04:13 +0000
Subject: [PATCH] timekeeping: Provide ktime_get_with_offset()
Provide a helper function which lets us implement ktime_t based
interfaces for real, boot and tai clocks.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
include/linux/timekeeping.h | 9 +++++++++
kernel/time/timekeeping.c | 27 +++++++++++++++++++++++++++
2 files changed, 36 insertions(+)
diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 3eb19e34cc204..a58e4b1879db5 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -98,7 +98,16 @@ extern void getboottime(struct timespec *ts);
/*
* ktime_t based interfaces
*/
+
+enum tk_offsets {
+ TK_OFFS_REAL,
+ TK_OFFS_BOOT,
+ TK_OFFS_TAI,
+ TK_OFFS_MAX,
+};
+
extern ktime_t ktime_get(void);
+extern ktime_t ktime_get_with_offset(enum tk_offsets offs);
extern ktime_t ktime_get_real(void);
extern ktime_t ktime_get_boottime(void);
extern ktime_t ktime_get_monotonic_offset(void);
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index d5be1425cc03e..7c5f5e4a006ce 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -423,6 +423,33 @@ ktime_t ktime_get(void)
}
EXPORT_SYMBOL_GPL(ktime_get);
+static ktime_t *offsets[TK_OFFS_MAX] = {
+ [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real,
+ [TK_OFFS_BOOT] = &tk_core.timekeeper.offs_boot,
+ [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai,
+};
+
+ktime_t ktime_get_with_offset(enum tk_offsets offs)
+{
+ struct timekeeper *tk = &tk_core.timekeeper;
+ unsigned int seq;
+ ktime_t base, *offset = offsets[offs];
+ s64 nsecs;
+
+ WARN_ON(timekeeping_suspended);
+
+ do {
+ seq = read_seqcount_begin(&tk_core.seq);
+ base = ktime_add(tk->base_mono, *offset);
+ nsecs = timekeeping_get_ns(tk);
+
+ } while (read_seqcount_retry(&tk_core.seq, seq));
+
+ return ktime_add_ns(base, nsecs);
+
+}
+EXPORT_SYMBOL_GPL(ktime_get_with_offset);
+
/**
* ktime_get_ts64 - get the monotonic clock in timespec64 format
* @ts: pointer to timespec variable
--
2.30.2