diff options
| -rw-r--r-- | arch/arm/cpu/arm920t/a320/timer.c | 134 |
1 files changed, 50 insertions, 84 deletions
diff --git a/arch/arm/cpu/arm920t/a320/timer.c b/arch/arm/cpu/arm920t/a320/timer.c index 443d31d..4bfcef2 100644 --- a/arch/arm/cpu/arm920t/a320/timer.c +++ b/arch/arm/cpu/arm920t/a320/timer.c @@ -18,20 +18,35 @@ */ #include <common.h> +#include <div64.h> #include <asm/io.h> #include <faraday/ftpmu010.h> #include <faraday/fttmr010.h> -static ulong timestamp; -static ulong lastdec; - -static struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE; +DECLARE_GLOBAL_DATA_PTR; #define TIMER_CLOCK 32768 #define TIMER_LOAD_VAL 0xffffffff +static inline unsigned long long tick_to_time(unsigned long long tick) +{ + tick *= CONFIG_SYS_HZ; + do_div(tick, gd->timer_rate_hz); + + return tick; +} + +static inline unsigned long long usec_to_tick(unsigned long long usec) +{ + usec *= gd->timer_rate_hz; + do_div(usec, 1000000); + + return usec; +} + int timer_init(void) { + struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE; unsigned int cr; debug("%s()\n", __func__); @@ -59,106 +74,57 @@ int timer_init(void) cr |= FTTMR010_TM3_ENABLE; writel(cr, &tmr->cr); - /* init the timestamp and lastdec value */ - reset_timer_masked(); + gd->timer_rate_hz = TIMER_CLOCK; + gd->tbu = gd->tbl = 0; return 0; } /* - * timer without interrupts - */ - -/* - * reset time - */ -void reset_timer_masked(void) -{ - /* capure current decrementer value time */ - lastdec = readl(&tmr->timer3_counter) / (TIMER_CLOCK / CONFIG_SYS_HZ); - timestamp = 0; /* start "advancing" time stamp from 0 */ - - debug("%s(): lastdec = %lx\n", __func__, lastdec); -} - -/* - * return timer ticks - */ -ulong get_timer_masked(void) -{ - /* current tick value */ - ulong now = readl(&tmr->timer3_counter) / (TIMER_CLOCK / CONFIG_SYS_HZ); - - debug("%s(): now = %lx, lastdec = %lx\n", __func__, now, lastdec); - - if (lastdec >= now) { - /* - * normal mode (non roll) - * move stamp fordward with absoulte diff ticks - */ - timestamp += lastdec - now; - } else { - /* - * we have overflow of the count down timer - * - * nts = ts + ld + (TLV - now) - * ts=old stamp, ld=time that passed before passing through -1 - * (TLV-now) amount of time after passing though -1 - * nts = new "advancing time stamp"...it could also roll and - * cause problems. - */ - timestamp += lastdec + TIMER_LOAD_VAL - now; - } - - lastdec = now; - - debug("%s() returns %lx\n", __func__, timestamp); - - return timestamp; -} - -/* - * return difference between timer ticks and base + * Get the current 64 bit timer tick count */ -ulong get_timer(ulong base) +unsigned long long get_ticks(void) { - debug("%s(%lx)\n", __func__, base); - return get_timer_masked() - base; + struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE; + ulong now = TIMER_LOAD_VAL - readl(&tmr->timer3_counter); + + /* increment tbu if tbl has rolled over */ + if (now < gd->tbl) + gd->tbu++; + gd->tbl = now; + return (((unsigned long long)gd->tbu) << 32) | gd->tbl; } -/* delay x useconds AND preserve advance timestamp value */ void __udelay(unsigned long usec) { - long tmo = usec * (TIMER_CLOCK / 1000) / 1000; - unsigned long now, last = readl(&tmr->timer3_counter); - - debug("%s(%lu)\n", __func__, usec); - while (tmo > 0) { - now = readl(&tmr->timer3_counter); - if (now > last) /* count down timer overflow */ - tmo -= TIMER_LOAD_VAL + last - now; - else - tmo -= last - now; - last = now; - } + unsigned long long start; + ulong tmo; + + start = get_ticks(); /* get current timestamp */ + tmo = usec_to_tick(usec); /* convert usecs to ticks */ + while ((get_ticks() - start) < tmo) + ; /* loop till time has passed */ } /* - * This function is derived from PowerPC code (read timebase as long long). - * On ARM it just returns the timer value. + * get_timer(base) can be used to check for timeouts or + * to measure elasped time relative to an event: + * + * ulong start_time = get_timer(0) sets start_time to the current + * time value. + * get_timer(start_time) returns the time elapsed since then. + * + * The time is used in CONFIG_SYS_HZ units! */ -unsigned long long get_ticks(void) +ulong get_timer(ulong base) { - debug("%s()\n", __func__); - return get_timer(0); + return tick_to_time(get_ticks()) - base; } /* - * This function is derived from PowerPC code (timebase clock frequency). - * On ARM it returns the number of timer ticks per second. + * Return the number of timer ticks per second. */ ulong get_tbclk(void) { - debug("%s()\n", __func__); - return CONFIG_SYS_HZ; + return gd->timer_rate_hz; } |