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, 9 insertions, 5 deletions

diff --git a/cpu/arm925t/interrupts.c b/cpu/arm925t/interrupts.c
index ea4aa3b..57bb4ea 100644
--- a/cpu/arm925t/interrupts.c
+++ b/cpu/arm925t/interrupts.c
@@ -275,20 +275,24 @@ void udelay_masked (unsigned long usec)
 #else
 
 	ulong tmo;
+	ulong endtime;
+	signed long diff;
 
-	if(usec >= 1000){		/* if "big" number, spread normalization to seconds */
+	if (usec >= 1000) {		/* if "big" number, spread normalization to seconds */
 		tmo = usec / 1000;	/* start to normalize for usec to ticks per sec */
 		tmo *= CFG_HZ;		/* find number of "ticks" to wait to achieve target */
 		tmo /= 1000;		/* finish normalize. */
-	}else{				/* else small number, don't kill it prior to HZ multiply */
+	} else {			/* else small number, don't kill it prior to HZ multiply */
 		tmo = usec * CFG_HZ;
 		tmo /= (1000*1000);
 	}
 
-	reset_timer_masked ();	/* set "advancing" timestamp to 0, set lastdec vaule */
+	endtime = get_timer_masked () + tmo;
 
-	while (get_timer_masked () < tmo) /* wait for time stamp to overtake tick number.*/
-		/*NOP*/;
+	do {
+		ulong now = get_timer_masked ();
+		diff = endtime - now;
+	} while (diff >= 0);
 #endif
 }