diff options
Diffstat (limited to 'cpu/arm_cortexa8/omap3')
-rw-r--r-- | cpu/arm_cortexa8/omap3/interrupts.c | 87 |
1 files changed, 28 insertions, 59 deletions
diff --git a/cpu/arm_cortexa8/omap3/interrupts.c b/cpu/arm_cortexa8/omap3/interrupts.c index 5d9c4e3..9f1189f 100644 --- a/cpu/arm_cortexa8/omap3/interrupts.c +++ b/cpu/arm_cortexa8/omap3/interrupts.c @@ -36,8 +36,6 @@ #include <asm/io.h> #include <asm/proc-armv/ptrace.h> -#define TIMER_LOAD_VAL 0 - #ifdef CONFIG_USE_IRQ /* enable IRQ interrupts */ void enable_interrupts(void) @@ -169,7 +167,17 @@ static ulong timestamp; static ulong lastinc; static gptimer_t *timer_base = (gptimer_t *)CONFIG_SYS_TIMERBASE; -/* nothing really to do with interrupts, just starts up a counter. */ +/* + * Nothing really to do with interrupts, just starts up a counter. + * We run the counter with 13MHz, divided by 8, resulting in timer + * frequency of 1.625MHz. With 32bit counter register, counter + * overflows in ~44min + */ + +/* 13MHz / 8 = 1.625MHz */ +#define TIMER_CLOCK (V_SCLK / (2 << CONFIG_SYS_PTV)) +#define TIMER_LOAD_VAL 0xffffffff + int interrupt_init(void) { /* start the counter ticking up, reload value on overflow */ @@ -201,81 +209,44 @@ void set_timer(ulong t) timestamp = t; } -/* delay x useconds AND perserve advance timstamp value */ +/* delay x useconds */ void udelay(unsigned long usec) { - ulong tmo, tmp; - - /* if "big" number, spread normalization to seconds */ - if (usec >= 1000) { - /* if "big" number, spread normalization to seconds */ - tmo = usec / 1000; - /* find number of "ticks" to wait to achieve target */ - tmo *= CONFIG_SYS_HZ; - tmo /= 1000; /* finish normalize. */ - } else {/* else small number, don't kill it prior to HZ multiply */ - tmo = usec * CONFIG_SYS_HZ; - tmo /= (1000 * 1000); + long tmo = usec * (TIMER_CLOCK / 1000) / 1000; + unsigned long now, last = readl(&timer_base->tcrr); + + while (tmo > 0) { + now = readl(&timer_base->tcrr); + if (last > now) /* count up timer overflow */ + tmo -= TIMER_LOAD_VAL - last + now; + else + tmo -= now - last; + last = now; } - - tmp = get_timer(0); /* get current timestamp */ - /* if setting this forward will roll time stamp */ - if ((tmo + tmp + 1) < tmp) - /* reset "advancing" timestamp to 0, set lastinc value */ - reset_timer_masked(); - else - tmo += tmp; /* else, set advancing stamp wake up time */ - while (get_timer_masked() < tmo) /* loop till event */ - /*NOP*/; } void reset_timer_masked(void) { /* reset time, capture current incrementer value time */ - lastinc = readl(&timer_base->tcrr); + lastinc = readl(&timer_base->tcrr) / (TIMER_CLOCK / CONFIG_SYS_HZ); timestamp = 0; /* start "advancing" time stamp from 0 */ } ulong get_timer_masked(void) { - ulong now = readl(&timer_base->tcrr); /* current tick value */ + /* current tick value */ + ulong now = readl(&timer_base->tcrr) / (TIMER_CLOCK / CONFIG_SYS_HZ); if (now >= lastinc) /* normal mode (non roll) */ /* move stamp fordward with absoulte diff ticks */ timestamp += (now - lastinc); else /* we have rollover of incrementer */ - timestamp += (0xFFFFFFFF - lastinc) + now; + timestamp += ((TIMER_LOAD_VAL / (TIMER_CLOCK / CONFIG_SYS_HZ)) + - lastinc) + now; lastinc = now; return timestamp; } -/* waits specified delay value and resets timestamp */ -void udelay_masked(unsigned long usec) -{ - ulong tmo; - ulong endtime; - signed long diff; - - /* if "big" number, spread normalization to seconds */ - if (usec >= 1000) { - /* start to normalize for usec to ticks per sec */ - tmo = usec / 1000; - /* find number of "ticks" to wait to achieve target */ - tmo *= CONFIG_SYS_HZ; - tmo /= 1000; /* finish normalize. */ - } else { /* else small number, */ - /* don't kill it prior to HZ multiply */ - tmo = usec * CONFIG_SYS_HZ; - tmo /= (1000 * 1000); - } - endtime = get_timer_masked() + tmo; - - do { - ulong now = get_timer_masked(); - diff = endtime - now; - } while (diff >= 0); -} - /* * This function is derived from PowerPC code (read timebase as long long). * On ARM it just returns the timer value. @@ -291,7 +262,5 @@ unsigned long long get_ticks(void) */ ulong get_tbclk(void) { - ulong tbclk; - tbclk = CONFIG_SYS_HZ; - return tbclk; + return CONFIG_SYS_HZ; } |