[U-Boot] [PATCH 05/10] ARM: highbank: set timer prescaler to 256

Rob Herring
2013-05-15T19:56:11Z

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 | 6 ++++--
arch/arm/include/asm/arch-armv7/systimer.h | 2 ++
2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/arm/cpu/armv7/highbank/timer.c b/arch/arm/cpu/armv7/highbank/timer.c
index da33d3c..d93de1e 100644
--- a/arch/arm/cpu/armv7/highbank/timer.c
+++ b/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();

diff --git a/arch/arm/include/asm/arch-armv7/systimer.h b/arch/arm/include/asm/arch-armv7/systimer.h
index e745e37..08125f7 100644
--- a/arch/arm/include/asm/arch-armv7/systimer.h
+++ b/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 */
--
1.8.1.2