Fix timer code for ARM systems: make sure that udelay() does not

reset timers so it's save to use udelay() in timeout code.

1 files changed, 6 insertions, 3 deletions

diff --git a/cpu/arm920t/imx/interrupts.c b/cpu/arm920t/imx/interrupts.c
index 12ae2faf28d..2f2e7545699 100644
--- a/cpu/arm920t/imx/interrupts.c
+++ b/cpu/arm920t/imx/interrupts.c
@@ -81,10 +81,13 @@ ulong get_timer_masked (void)
 
 void udelay_masked (unsigned long usec)
 {
-	ulong start = get_timer_masked();
+	ulong endtime = get_timer_masked() + usec;
+	signed long diff;
 
-	while (get_timer_masked () - start < usec )
-		/*NOP*/;
+	do {
+		ulong now = get_timer_masked ();
+		diff = endtime - now;
+	} while (diff >= 0);
 }
 
 void udelay (unsigned long usec)