OMAP3: Fix timer handling to 1ms and CONFIG_SYS_HZ to 1000

Signed-off-by: Dirk Behme <dirk.behme@googlemail.com>
Signed-off-by: Manikandan Pillai <mani.pillai@ti.com>

1 files changed, 28 insertions, 59 deletions

diff --git a/cpu/arm_cortexa8/omap3/interrupts.c b/cpu/arm_cortexa8/omap3/interrupts.c
index 5d9c4e3..9f1189f 100644
--- a/cpu/arm_cortexa8/omap3/interrupts.c
+++ b/cpu/arm_cortexa8/omap3/interrupts.c
@@ -36,8 +36,6 @@
 #include <asm/io.h>
 #include <asm/proc-armv/ptrace.h>
 
-#define TIMER_LOAD_VAL 0
-
 #ifdef CONFIG_USE_IRQ
 /* enable IRQ interrupts */
 void enable_interrupts(void)
@@ -169,7 +167,17 @@ static ulong timestamp;
 static ulong lastinc;
 static gptimer_t *timer_base = (gptimer_t *)CONFIG_SYS_TIMERBASE;
 
-/* nothing really to do with interrupts, just starts up a counter. */
+/*
+ * Nothing really to do with interrupts, just starts up a counter.
+ * We run the counter with 13MHz, divided by 8, resulting in timer
+ * frequency of 1.625MHz. With 32bit counter register, counter
+ * overflows in ~44min
+ */
+
+/* 13MHz / 8 = 1.625MHz */
+#define TIMER_CLOCK	(V_SCLK / (2 << CONFIG_SYS_PTV))
+#define TIMER_LOAD_VAL	0xffffffff
+
 int interrupt_init(void)
 {
 	/* start the counter ticking up, reload value on overflow */
@@ -201,81 +209,44 @@ void set_timer(ulong t)
 	timestamp = t;
 }
 
-/* delay x useconds AND perserve advance timstamp value */
+/* delay x useconds */
 void udelay(unsigned long usec)
 {
-	ulong tmo, tmp;
-
-	/* if "big" number, spread normalization to seconds */
-	if (usec >= 1000) {
-		/* if "big" number, spread normalization to seconds */
-		tmo = usec / 1000;
-		/* find number of "ticks" to wait to achieve target */
-		tmo *= CONFIG_SYS_HZ;
-		tmo /= 1000;	/* finish normalize. */
-	} else {/* else small number, don't kill it prior to HZ multiply */
-		tmo = usec * CONFIG_SYS_HZ;
-		tmo /= (1000 * 1000);
+	long tmo = usec * (TIMER_CLOCK / 1000) / 1000;
+	unsigned long now, last = readl(&timer_base->tcrr);
+
+	while (tmo > 0) {
+		now = readl(&timer_base->tcrr);
+		if (last > now) /* count up timer overflow */
+			tmo -= TIMER_LOAD_VAL - last + now;
+		else
+			tmo -= now - last;
+		last = now;
 	}
-
-	tmp = get_timer(0);	/* get current timestamp */
-	/* if setting this forward will roll time stamp */
-	if ((tmo + tmp + 1) < tmp)
-		/* reset "advancing" timestamp to 0, set lastinc value */
-		reset_timer_masked();
-	else
-		tmo += tmp;	/* else, set advancing stamp wake up time */
-	while (get_timer_masked() < tmo)	/* loop till event */
-		 /*NOP*/;
 }
 
 void reset_timer_masked(void)
 {
 	/* reset time, capture current incrementer value time */
-	lastinc = readl(&timer_base->tcrr);
+	lastinc = readl(&timer_base->tcrr) / (TIMER_CLOCK / CONFIG_SYS_HZ);
 	timestamp = 0;		/* start "advancing" time stamp from 0 */
 }
 
 ulong get_timer_masked(void)
 {
-	ulong now = readl(&timer_base->tcrr); /* current tick value */
+	/* current tick value */
+	ulong now = readl(&timer_base->tcrr) / (TIMER_CLOCK / CONFIG_SYS_HZ);
 
 	if (now >= lastinc)	/* normal mode (non roll) */
 		/* move stamp fordward with absoulte diff ticks */
 		timestamp += (now - lastinc);
 	else	/* we have rollover of incrementer */
-		timestamp += (0xFFFFFFFF - lastinc) + now;
+		timestamp += ((TIMER_LOAD_VAL / (TIMER_CLOCK / CONFIG_SYS_HZ))
+				- lastinc) + now;
 	lastinc = now;
 	return timestamp;
 }
 
-/* waits specified delay value and resets timestamp */
-void udelay_masked(unsigned long usec)
-{
-	ulong tmo;
-	ulong endtime;
-	signed long diff;
-
-	/* if "big" number, spread normalization to seconds */
-	if (usec >= 1000) {
-		/* start to normalize for usec to ticks per sec */
-		tmo = usec / 1000;
-		/* find number of "ticks" to wait to achieve target */
-		tmo *= CONFIG_SYS_HZ;
-		tmo /= 1000;	/* finish normalize. */
-	} else {		/* else small number, */
-				/* don't kill it prior to HZ multiply */
-		tmo = usec * CONFIG_SYS_HZ;
-		tmo /= (1000 * 1000);
-	}
-	endtime = get_timer_masked() + tmo;
-
-	do {
-		ulong now = get_timer_masked();
-		diff = endtime - now;
-	} while (diff >= 0);
-}
-
 /*
  * This function is derived from PowerPC code (read timebase as long long).
  * On ARM it just returns the timer value.
@@ -291,7 +262,5 @@ unsigned long long get_ticks(void)
  */
 ulong get_tbclk(void)
 {
-	ulong tbclk;
-	tbclk = CONFIG_SYS_HZ;
-	return tbclk;
+	return CONFIG_SYS_HZ;
 }