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[13/13] OMAP: timekeeping: time should not stop during suspend

Message ID 1262973571-25796-14-git-send-email-khilman@deeprootsystems.com (mailing list archive)
State Accepted
Delegated to: Kevin Hilman
Headers show

Commit Message

Kevin Hilman Jan. 8, 2010, 5:59 p.m. UTC
None
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Patch

diff --git a/arch/arm/plat-omap/common.c b/arch/arm/plat-omap/common.c
index bf1eaf3..dddc027 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