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authorManikandan Pillai <mani.pillai@ti.com>2009-04-21 17:29:05 +0200
committerWolfgang Denk <wd@denx.de>2009-04-30 23:56:01 +0200
commitd3a513c23ba4100d6983161cdc1f747dfd087bbd (patch)
treec14a0214a8b84b28094385b8cc2d285ca4f6e260 /cpu/arm_cortexa8/omap3
parent9d5e4d368129ae343ebdd340859ab144e2fb87c4 (diff)
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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>
Diffstat (limited to 'cpu/arm_cortexa8/omap3')
-rw-r--r--cpu/arm_cortexa8/omap3/interrupts.c87
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;
}