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Introduce common timer functions

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Many platforms duplicate pretty much the same timer code yet they all have
a 32-bit freerunning counter register. Create a common implementation that
minimally requires 2 or 3 defines to add timer support:

CONFIG_SYS_TIMER_RATE - Clock rate of the timer counter
CONFIG_SYS_TIMER_COUNTER - Address of 32-bit counter
CONFIG_SYS_TIMER_COUNTS_DOWN - Define if counter counts down

All functions are weak or ifdef'ed so they can still be overriden by any
platform.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
This commit is contained in:
Rob Herring 2013-10-04 10:22:41 -05:00 committed by Tom Rini
parent e32a268b6f
commit 8dfafdde88
2 changed files with 75 additions and 0 deletions
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2
include/asm-generic/global_data.h
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@ -72,6 +72,8 @@ typedef struct global_data {
#if defined(CONFIG_SYS_I2C)
int cur_i2c_bus; /* current used i2c bus */
#endif
unsigned long timebase_h;
unsigned long timebase_l;
struct arch_global_data arch; /* architecture-specific data */
} gd_t;
#endif

73
lib/time.c
View file

@ -7,6 +7,8 @@
#include <common.h>
#include <watchdog.h>
#include <div64.h>
#include <asm/io.h>
#if CONFIG_SYS_HZ != 1000
#warning "CONFIG_SYS_HZ must be 1000 and should not be defined by platforms"
@ -16,6 +18,77 @@
# define CONFIG_WD_PERIOD (10 * 1000 * 1000) /* 10 seconds default*/
#endif
DECLARE_GLOBAL_DATA_PTR;
#ifdef CONFIG_SYS_TIMER_RATE
ulong notrace get_tbclk(void)
{
return CONFIG_SYS_TIMER_RATE;
}
#endif
#ifdef CONFIG_SYS_TIMER_COUNTER
unsigned long notrace timer_read_counter(void)
{
#ifdef CONFIG_SYS_TIMER_COUNTS_DOWN
return ~readl(CONFIG_SYS_TIMER_COUNTER);
#else
return readl(CONFIG_SYS_TIMER_COUNTER);
#endif
}
#else
extern unsigned long timer_read_counter(void);
#endif
unsigned long long __weak notrace get_ticks(void)
{
unsigned long now = timer_read_counter();
/* increment tbu if tbl has rolled over */
if (now < gd->timebase_l)
gd->timebase_h++;
gd->timebase_l = now;
return ((unsigned long long)gd->timebase_h << 32) | gd->timebase_l;
}
static unsigned long long notrace tick_to_time(unsigned long long tick)
{
unsigned int div = get_tbclk();
tick *= CONFIG_SYS_HZ;
do_div(tick, div);
return tick;
}
ulong __weak get_timer(ulong base)
{
return tick_to_time(get_ticks()) - base;
}
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)
{
unsigned long long tick = usec * get_tbclk();
usec *= get_tbclk();
do_div(tick, 1000000);
return tick;
}
void __weak __udelay(unsigned long usec)
{
unsigned long long tmp;
ulong tmo;
tmo = usec_to_tick(usec);
tmp = get_ticks() + tmo; /* get current timestamp */
while (get_ticks() < tmp) /* loop till event */
/*NOP*/;
}
/* ------------------------------------------------------------------------- */
void udelay(unsigned long usec)