1 files changed, 26 insertions, 0 deletions

diff --git a/arch/arm/plat-omap/common.c b/arch/arm/plat-omap/common.c
index bf1eaf3a27d4..dddc0273bc8b 100644
--- a/arch/arm/plat-omap/common.c
+++ b/arch/arm/plat-omap/common.c
@@ -172,6 +172,32 @@ unsigned long long sched_clock(void)
                                   clocksource_32k.mult, clocksource_32k.shift);
 }
 
+/**
+ * read_persistent_clock -  Return time from a persistent clock.
+ *
+ * Reads the time from a source which isn't disabled during PM, the
+ * 32k sync timer.  Convert the cycles elapsed since last read into
+ * nsecs and adds to a monotonically increasing timespec.
+ */
+static struct timespec persistent_ts;
+static cycles_t cycles, last_cycles;
+void read_persistent_clock(struct timespec *ts)
+{
+        unsigned long long nsecs;
+        cycles_t delta;
+        struct timespec *tsp = &persistent_ts;
+
+        last_cycles = cycles;
+        cycles = clocksource_32k.read(&clocksource_32k);
+        delta = cycles - last_cycles;
+
+        nsecs = clocksource_cyc2ns(delta,
+                                   clocksource_32k.mult, clocksource_32k.shift);
+
+        timespec_add_ns(tsp, nsecs);
+        *ts = *tsp;
+}
+
 static int __init omap_init_clocksource_32k(void)
 {
         static char err[] __initdata = KERN_ERR