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Fix timer overflow in DaVinci 

Signed-off-by: Dirk Behme <dirk.behme@gmail.com>
This commit is contained in:
Peter Pearse 2008-02-01 16:50:24 +00:00
parent fe891ecf4d
commit ea686f52e4
1 changed files with 9 additions and 4 deletions
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13
cpu/arm926ejs/davinci/timer.c
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@ -61,6 +61,11 @@ davinci_timer *timer = (davinci_timer *)CFG_TIMERBASE;
#define TIMER_LOAD_VAL (CFG_HZ_CLOCK / CFG_HZ)
#define READ_TIMER timer->tim34
/* Timer runs with CFG_HZ_CLOCK, currently 27MHz. To avoid wrap
around of timestamp already after min ~159s, divide it, e.g. by 16.
timestamp will then wrap around all min ~42min */
#define DIV(x) ((x) >> 4)
static ulong timestamp;
static ulong lastinc;
@ -101,20 +106,20 @@ void udelay(unsigned long usec)
void reset_timer_masked(void)
{
lastinc = READ_TIMER;
lastinc = DIV(READ_TIMER);
timestamp = 0;
}
ulong get_timer_raw(void)
{
ulong now = READ_TIMER;
ulong now = DIV(READ_TIMER);
if (now >= lastinc) {
/* normal mode */
timestamp += now - lastinc;
} else {
/* overflow ... */
timestamp += now + TIMER_LOAD_VAL - lastinc;
timestamp += now + DIV(TIMER_LOAD_VAL) - lastinc;
}
lastinc = now;
return timestamp;
@ -122,7 +127,7 @@ ulong get_timer_raw(void)
ulong get_timer_masked(void)
{
return(get_timer_raw() / TIMER_LOAD_VAL);
return(get_timer_raw() / DIV(TIMER_LOAD_VAL));
}
void udelay_masked(unsigned long usec)