From 101e8dfa2a8b045c6655bf2b3d6fba8d378453cd Mon Sep 17 00:00:00 2001
From: wdenk <wdenk>
Date: Mon, 4 Apr 2005 12:08:28 +0000
Subject: Fix timer code for ARM systems: make sure that udelay() does not
 reset timers so it's save to use udelay() in timeout code.

---
 cpu/arm720t/interrupts.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

(limited to 'cpu/arm720t')

diff --git a/cpu/arm720t/interrupts.c b/cpu/arm720t/interrupts.c
index a7ea70a26..ab28e602c 100644
--- a/cpu/arm720t/interrupts.c
+++ b/cpu/arm720t/interrupts.c
@@ -358,15 +358,24 @@ ulong get_timer_masked (void)
 void udelay_masked (unsigned long usec)
 {
 	ulong tmo;
+	ulong endtime;
+	signed long diff;
 
-	tmo = usec / 1000;
-	tmo *= CFG_HZ;
-	tmo /= 1000;
+	if (usec >= 1000) {
+		tmo = usec / 1000;
+		tmo *= CFG_HZ;
+		tmo /= 1000;
+	} else {
+		tmo = usec * CFG_HZ;
+		tmo /= (1000*1000);
+	}
 
-	reset_timer_masked ();
+	endtime = get_timer_masked () + tmo;
 
-	while (get_timer_masked () < tmo)
-		/*NOP*/;
+	do {
+		ulong now = get_timer_masked ();
+		diff = endtime - now;
+	} while (diff >= 0);
 }
 
 #elif defined(CONFIG_S3C4510B)
-- 
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