1 files changed, 21 insertions, 0 deletions
diff --git a/chip/npcx/hwtimer.c b/chip/npcx/hwtimer.c
index 76f1822a94..75b026c939 100644
--- a/chip/npcx/hwtimer.c
+++ b/chip/npcx/hwtimer.c
@@ -16,6 +16,7 @@
 #include "console.h"
 #include "task.h"
 #include "timer.h"
+#include "registers.h"
 #include "util.h"
 
 /* Depth of event timer */
@@ -340,3 +341,23 @@ int __hw_clock_source_init(uint32_t start_t)
 
 	return NPCX_IRQ_ITIM32;
 }
+
+/*
+ * Unrolled udelay. It preserves LR, which points to the root cause of WD crash.
+ */
+__override void udelay(unsigned us)
+{
+	uint32_t cnt, cnt2, t0;
+
+	cnt = NPCX_ITCNT32;
+	while ((cnt2 = NPCX_ITCNT32) != cnt)
+		cnt = cnt2;
+
+	t0 = TICK_ITIM32_MAX_CNT - cnt;
+
+	do {
+		cnt = NPCX_ITCNT32;
+		while ((cnt2 = NPCX_ITCNT32) != cnt)
+			cnt = cnt2;
+	} while (TICK_ITIM32_MAX_CNT - cnt - t0 <= us);
+}