ARM: highbank: set timer prescaler to 256

The 150MHz clock rate gives u-boot time functions problems and there's no
benefit to a fast clock, so lower the rate.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>

arch/arm/cpu/armv7/highbank/timer.c

@@ -26,7 +26,7 @@
 
 #undef SYSTIMER_BASE
 #define SYSTIMER_BASE		0xFFF34000	/* Timer 0 and 1 base	*/
-#define SYSTIMER_RATE		150000000
+#define SYSTIMER_RATE		(150000000 / 256)
 
 static ulong timestamp;
 static ulong lastinc;
@@ -40,9 +40,11 @@ int timer_init(void)
 	/*
 	 * Setup timer0
 	 */
+	writel(0, &systimer_base->timer0control);
 	writel(SYSTIMER_RELOAD, &systimer_base->timer0load);
 	writel(SYSTIMER_RELOAD, &systimer_base->timer0value);
-	writel(SYSTIMER_EN | SYSTIMER_32BIT, &systimer_base->timer0control);
+	writel(SYSTIMER_EN | SYSTIMER_32BIT | SYSTIMER_PRESC_256,
+		&systimer_base->timer0control);
 
 	reset_timer_masked();
 

arch/arm/include/asm/arch-armv7/systimer.h

@@ -30,6 +30,8 @@
 #define SYSTIMER_RELOAD		0xFFFFFFFF
 #define SYSTIMER_EN		(1 << 7)
 #define SYSTIMER_32BIT		(1 << 1)
+#define SYSTIMER_PRESC_16	(1 << 2)
+#define SYSTIMER_PRESC_256	(1 << 3)
 
 struct systimer {
 	u32 timer0load;		/* 0x00 */