timer: Add timestamp_expired() to check for expiry

Rather than open code this each time, create a function for this. The
wrap-around condition may not be needed, if the timer starts at zero,
since we have 64 bits to play with.

BUG=chrome-os-partner:9424
TEST=build and boot on daisy

Change-Id: I84ae651212769b5927c452bc03f31f60a25a829e
Signed-off-by: Simon Glass <sjg@chromium.org>

2 files changed, 14 insertions, 0 deletions

diff --git a/core/cortex-m/timer.c b/core/cortex-m/timer.c
index ba45bc8783..0078936f5a 100644
--- a/core/cortex-m/timer.c
+++ b/core/cortex-m/timer.c
@@ -37,6 +37,12 @@ static void expire_timer(task_id_t tskid)
 	task_set_event(tskid, TASK_EVENT_TIMER, 0);
 }
 
+int timestamp_expired(timestamp_t deadline)
+{
+	timestamp_t now = get_time();
+
+	return ((int64_t)(now.val - deadline.val) >= 0);
+}
 
 void process_timers(int overflow)
 {
diff --git a/include/timer.h b/include/timer.h
index 4e132ebd6f..796318a1d0 100644
--- a/include/timer.h
+++ b/include/timer.h
@@ -30,6 +30,14 @@ int timer_arm(timestamp_t tstamp, task_id_t tskid);
 /* Cancel a running timer for the specified task id. */
 int timer_cancel(task_id_t tskid);
 
+/**
+ * Check if a timestamp has passed / expired
+ *
+ * @param deadline	deadline timer value to check
+ * @return 0 if deadline has not yet passed, 1 if it has passed
+ */
+int timestamp_expired(timestamp_t deadline);
+
 /* Busy-wait the selected number of microseconds.  Note that calling this
  * with us>1000 may impact system performance; use usleep for longer delays. */
 void udelay(unsigned us);