From bca0f7925cadbebf47c6b7d77a20cb5b03908bb4 Mon Sep 17 00:00:00 2001
From: Lorenz Meier <lorenz@px4.io>
Date: Sun, 20 Jan 2019 17:29:49 +0100
Subject: [PATCH] SAMv7: Add atomic and non-atomic HRT calls This reduces
 interrupt load significantly.

---
 src/drivers/samv7/drv_hrt.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/drivers/samv7/drv_hrt.c b/src/drivers/samv7/drv_hrt.c
index dfafe206f4..a38e42de5a 100644
--- a/src/drivers/samv7/drv_hrt.c
+++ b/src/drivers/samv7/drv_hrt.c
@@ -680,6 +680,17 @@ abstime_to_ts(struct timespec *ts, hrt_abstime abstime)
  */
 hrt_abstime
 hrt_elapsed_time(const volatile hrt_abstime *then)
+{
+	hrt_abstime delta = hrt_absolute_time() - *then;
+
+	return delta;
+}
+
+/**
+ * Compare a time value with the current time as atomic operation.
+ */
+hrt_abstime
+hrt_elapsed_time_atomic(const volatile hrt_abstime *then)
 {
 	irqstate_t flags = enter_critical_section();