Correct ARM Versatile Timer Initialization

 - 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 <gururajakr@sanyo.co.in>

diff --git a/cpu/arm926ejs/versatile/timer.c b/cpu/arm926ejs/versatile/timer.c
old mode 100644 (file)
new mode 100755 (executable)
index 32872d2..f01f318
--- a/cpu/arm926ejs/versatile/timer.c
+++ b/cpu/arm926ejs/versatile/timer.c
@@ -46,12 +46,43 @@
 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   tmr_ctrl_val;
+
+       /* 1st disable the Timer */
+       tmr_ctrl_val = *(volatile ulong *)(CFG_TIMERBASE + 8);
+       tmr_ctrl_val &= ~TIMER_ENABLE;
+       *(volatile ulong *)(CFG_TIMERBASE + 8) = tmr_ctrl_val;
+
+       /*
+        * 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
+        */
+       tmr_ctrl_val = *(volatile ulong *)(CFG_TIMERBASE + 8);
+       tmr_ctrl_val &= ~(TIMER_MODE_MSK | TIMER_INT_EN | TIMER_PRS_MSK | TIMER_SIZE_MSK | TIMER_ONE_SHT );
+       tmr_ctrl_val |= (TIMER_ENABLE | TIMER_PRS_8S);
+
+       *(volatile ulong *)(CFG_TIMERBASE + 8) = tmr_ctrl_val;
 
        /* init the timestamp and lastdec value */
        reset_timer_masked();