diff options
Diffstat (limited to 'cpu')
| -rw-r--r-- | cpu/arm926ejs/at91/timer.c | 82 |
1 files changed, 44 insertions, 38 deletions
diff --git a/cpu/arm926ejs/at91/timer.c b/cpu/arm926ejs/at91/timer.c index fec545b6652..c84cb5e96f7 100644 --- a/cpu/arm926ejs/at91/timer.c +++ b/cpu/arm926ejs/at91/timer.c @@ -27,7 +27,9 @@ #include <asm/arch/at91_pit.h> #include <asm/arch/at91_pmc.h> #include <asm/arch/at91_rstc.h> +#include <asm/arch/clk.h> #include <asm/arch/io.h> +#include <div64.h> /* * We're using the AT91CAP9/SAM9 PITC in 32 bit mode, by @@ -36,11 +38,26 @@ #define TIMER_LOAD_VAL 0xfffff #define READ_RESET_TIMER at91_sys_read(AT91_PIT_PIVR) #define READ_TIMER at91_sys_read(AT91_PIT_PIIR) -#define TIMER_FREQ (AT91C_MASTER_CLOCK << 4) -#define TICKS_TO_USEC(ticks) ((ticks) / 6) -ulong get_timer_masked(void); -ulong resettime; +static ulong timestamp; +static ulong lastinc; +static ulong timer_freq; + +static inline unsigned long long tick_to_time(unsigned long long tick) +{ + tick *= CONFIG_SYS_HZ; + do_div(tick, timer_freq); + + return tick; +} + +static inline unsigned long long usec_to_tick(unsigned long long usec) +{ + usec *= timer_freq; + do_div(usec, 1000000); + + return usec; +} /* nothing really to do with interrupts, just starts up a counter. */ int timer_init(void) @@ -56,41 +73,49 @@ int timer_init(void) reset_timer_masked(); + timer_freq = get_mck_clk_rate() >> 4; + return 0; } /* * timer without interrupts */ - -static inline ulong get_timer_raw(void) +unsigned long long get_ticks(void) { ulong now = READ_TIMER; - if (now >= resettime) - return now - resettime; - else - return 0xFFFFFFFFUL - (resettime - now) ; + if (now >= lastinc) /* normal mode (non roll) */ + /* move stamp forward with absolut diff ticks */ + timestamp += (now - lastinc); + else /* we have rollover of incrementer */ + timestamp += (0xFFFFFFFF - lastinc) + now; + lastinc = now; + return timestamp; } void reset_timer_masked(void) { - resettime = READ_TIMER; + /* reset time */ + lastinc = READ_TIMER; /* capture current incrementer value time */ + timestamp = 0; /* start "advancing" time stamp from 0 */ } ulong get_timer_masked(void) { - return TICKS_TO_USEC(get_timer_raw()); - + return tick_to_time(get_ticks()); } -void udelay_masked(unsigned long usec) +void udelay(unsigned long usec) { - ulong tmp; + unsigned long long tmp; + ulong tmo; - tmp = get_timer(0); - while (get_timer(tmp) < usec) /* our timer works in usecs */ - ; /* NOP */ + tmo = usec_to_tick(usec); + tmp = get_ticks() + tmo; /* get current timestamp */ + + while (get_ticks() < tmp) /* loop till event */ + /*NOP*/; } void reset_timer(void) @@ -100,26 +125,7 @@ void reset_timer(void) ulong get_timer(ulong base) { - ulong now = get_timer_masked(); - - if (now >= base) - return now - base; - else - return TICKS_TO_USEC(0xFFFFFFFFUL) - (base - now) ; -} - -void udelay(unsigned long usec) -{ - udelay_masked(usec); -} - -/* - * This function is derived from PowerPC code (read timebase as long long). - * On ARM it just returns the timer value. - */ -unsigned long long get_ticks(void) -{ - return get_timer(0); + return get_timer_masked () - base; } /* |