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lib/time.c cleanups

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As I initially suspected overflow in time handling, I took a detailed
look at lib/time.c. This adds comments about units being used, reduces
amount of type casting being done, and makes __udelay() always wait at
least one tick. (Current code could do no delaying at all for short
delays).

Signed-off-by: Pavel Machek <pavel@denx.de>
This commit is contained in:
Pavel Machek 2014-07-13 13:14:27 +02:00 committed by Tom Rini
parent 288afdc9b9
commit fccacd3b4c
1 changed files with 10 additions and 8 deletions
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18
lib/time.c
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@ -15,12 +15,13 @@
#endif
#ifndef CONFIG_WD_PERIOD
# define CONFIG_WD_PERIOD (10 * 1000 * 1000) /* 10 seconds default*/
# define CONFIG_WD_PERIOD (10 * 1000 * 1000) /* 10 seconds default */
#endif
DECLARE_GLOBAL_DATA_PTR;
#ifdef CONFIG_SYS_TIMER_RATE
/* Returns tick rate in ticks per second */
ulong notrace get_tbclk(void)
{
return CONFIG_SYS_TIMER_RATE;
@ -51,9 +52,10 @@ unsigned long long __weak notrace get_ticks(void)
return ((unsigned long long)gd->timebase_h << 32) | gd->timebase_l;
}
static unsigned long long notrace tick_to_time(uint64_t tick)
/* Returns time in milliseconds */
static unsigned long long notrace tick_to_time(unsigned long long tick)
{
unsigned int div = get_tbclk();
ulong div = get_tbclk();
tick *= CONFIG_SYS_HZ;
do_div(tick, div);
@ -65,6 +67,7 @@ int __weak timer_init(void)
return 0;
}
/* Returns time in milliseconds */
ulong __weak get_timer(ulong base)
{
return tick_to_time(get_ticks()) - base;
@ -74,9 +77,10 @@ unsigned long __weak notrace timer_get_us(void)
{
return tick_to_time(get_ticks() * 1000);
}
static unsigned long long usec_to_tick(unsigned long usec)
{
uint64_t tick = usec;
unsigned long long tick = usec;
tick *= get_tbclk();
do_div(tick, 1000000);
return tick;
@ -85,12 +89,10 @@ static unsigned long long usec_to_tick(unsigned long usec)
void __weak __udelay(unsigned long usec)
{
unsigned long long tmp;
ulong tmo;
tmo = usec_to_tick(usec);
tmp = get_ticks() + tmo; /* get current timestamp */
tmp = get_ticks() + usec_to_tick(usec); /* get current timestamp */
while (get_ticks() < tmp) /* loop till event */
while (get_ticks() < tmp+1) /* loop till event */
/*NOP*/;
}