- According to ARM Dual-Timer Module (SP804) TRM (ARM DDI0271),
-- Timer Value Register @ TIMER Base + 4 is Read-only.
-- Prescale Value (Bits 3-2 of TIMER Control register)
can only be one of 00,01,10. 11 is undefined.
-- CFG_HZ for Versatile board is set to
#define CFG_HZ (1000000 / 256)
So Prescale bits is set to indicate
- 8 Stages of Prescale, Clock divided by 256
- The Timer Control Register has one Undefined/Shouldn't Use Bit
So we should do read/modify/write Operation
Signed-off-by: Gururaja Hebbar <[EMAIL PROTECTED]>
---
cpu/arm926ejs/versatile/timer.c | 37 +++++++++++++++++++++++++++++++++----
1 files changed, 33 insertions(+), 4 deletions(-)
diff --git a/cpu/arm926ejs/versatile/timer.c b/cpu/arm926ejs/versatile/timer.c
index 32872d2..17ba387 100755
--- a/cpu/arm926ejs/versatile/timer.c
+++ b/cpu/arm926ejs/versatile/timer.c
@@ -46,12 +46,41 @@
static ulong timestamp;
static ulong lastdec;
-/* nothing really to do with interrupts, just starts up a counter. */
+#define TIMER_ENABLE (1 << 7)
+#define TIMER_MODE_MSK (1 << 6)
+#define TIMER_MODE_FR (0 << 6)
+#define TIMER_MODE_PD (1 << 6)
+
+#define TIMER_INT_EN (1 << 5)
+#define TIMER_PRS_MSK (3 << 2)
+#define TIMER_PRS_8S (1 << 3)
+#define TIMER_SIZE_MSK (1 << 2)
+#define TIMER_ONE_SHT (1 << 0)
+
int timer_init (void)
{
- *(volatile ulong *)(CFG_TIMERBASE + 0) = CFG_TIMER_RELOAD; /*
TimerLoad */
- *(volatile ulong *)(CFG_TIMERBASE + 4) = CFG_TIMER_RELOAD; /*
TimerValue */
- *(volatile ulong *)(CFG_TIMERBASE + 8) = 0x8C;
+ ulong TmrCntrlVal;
+
+ /*1st disable the Timer*/
+ TmrCntrlVal = *(volatile ulong *)(CFG_TIMERBASE + 8);
+ TmrCntrlVal &= ~TIMER_ENABLE;
+ *(volatile ulong *)(CFG_TIMERBASE + 8) = TmrCntrlVal;
+
+ /* The Timer Control Register has one Undefined/Shouldn't Use Bit
+ * So we should do read/modify/write Operation
+ */
+
+ /* Timer Mode : Free Running
+ * Interrupt : Disabled
+ * Prescale : 8 Stage, Clk/256
+ * Tmr Siz : 16 Bit Counter
+ * Tmr in Wrapping Mode
+ */
+ TmrCntrlVal = *(volatile ulong *)(CFG_TIMERBASE + 8);
+ TmrCntrlVal &= ~(TIMER_MODE_MSK | TIMER_INT_EN | TIMER_PRS_MSK |
TIMER_SIZE_MSK | TIMER_ONE_SHT );
+ TmrCntrlVal |= (TIMER_ENABLE | TIMER_PRS_8S);
+
+ *(volatile ulong *)(CFG_TIMERBASE + 8) = TmrCntrlVal;
/* init the timestamp and lastdec value */
reset_timer_masked();
--
1.5.6.4
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