Provide interfaces similar to the ktime_get*() family which provide access
to the auxiliary clocks.
These interfaces have a boolean return value, which indicates whether the
accessed clock is valid or not.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/timekeeping.h | 11 +++++++
kernel/time/timekeeping.c | 62 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 73 insertions(+)
---
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -263,6 +263,17 @@ extern bool timekeeping_rtc_skipresume(v
extern void timekeeping_inject_sleeptime64(const struct timespec64 *delta);
+/*
+ * Auxiliary clock interfaces
+ */
+#ifdef CONFIG_POSIX_AUX_CLOCKS
+extern bool ktime_get_aux(clockid_t id, ktime_t *kt);
+extern bool ktime_get_aux_ts64(clockid_t id, struct timespec64 *kt);
+#else
+static inline bool ktime_get_aux(clockid_t id, ktime_t *kt) { return false; }
+static inline bool ktime_get_aux_ts64(clockid_t id, struct timespec64 *kt) { return false; }
+#endif
+
/**
* struct system_time_snapshot - simultaneous raw/real time capture with
* counter value
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -2659,6 +2659,23 @@ EXPORT_SYMBOL(hardpps);
/* Bitmap for the activated auxiliary timekeepers */
static unsigned long aux_timekeepers;
+static inline bool aux_valid_clockid(clockid_t id)
+{
+ return id >= CLOCK_AUX && id <= CLOCK_AUX_LAST;
+}
+
+static inline unsigned int clockid_to_tkid(unsigned int id)
+{
+ return TIMEKEEPER_AUX + id - CLOCK_AUX;
+}
+
+static inline struct tk_data *aux_get_tk_data(clockid_t id)
+{
+ if (!aux_valid_clockid(id))
+ return NULL;
+ return &timekeeper_data[clockid_to_tkid(id)];
+}
+
/* Invoked from timekeeping after a clocksource change */
static void tk_aux_update_clocksource(void)
{
@@ -2679,6 +2696,51 @@ static void tk_aux_update_clocksource(vo
}
}
+/**
+ * ktime_get_aux - Get TAI time for a AUX clock
+ * @id: ID of the clock to read (CLOCK_AUX...)
+ * @kt: Pointer to ktime_t to store the time stamp
+ *
+ * Returns: True if the timestamp is valid, false otherwise
+ */
+bool ktime_get_aux(clockid_t id, ktime_t *kt)
+{
+ struct tk_data *tkd = aux_get_tk_data(id);
+ struct timekeeper *tk;
+ unsigned int seq;
+ ktime_t base;
+ u64 nsecs;
+
+ WARN_ON(timekeeping_suspended);
+
+ if (!tkd)
+ return false;
+
+ tk = &tkd->timekeeper;
+ do {
+ seq = read_seqcount_begin(&tkd->seq);
+ if (!tk->clock_valid)
+ return false;
+
+ base = ktime_add(tk->tkr_mono.base, tk->offs_aux);
+ nsecs = timekeeping_get_ns(&tk->tkr_mono);
+ } while (read_seqcount_retry(&tkd->seq, seq));
+
+ *kt = ktime_add_ns(base, nsecs);
+ return true;
+}
+EXPORT_SYMBOL_GPL(ktime_get_aux);
+
+bool ktime_get_aux_ts64(clockid_t id, struct timespec64 *ts)
+{
+ ktime_t now;
+
+ if (!ktime_get_aux(id, &now))
+ return false;
+ *ts = ktime_to_timespec64(now);
+ return true;
+}
+
static __init void tk_aux_setup(void)
{
for (int i = TIMEKEEPER_AUX; i <= TIMEKEEPER_AUX_LAST; i++)