diff options
Diffstat (limited to 'src/timer.c')
-rw-r--r-- | src/timer.c | 52 |
1 files changed, 28 insertions, 24 deletions
diff --git a/src/timer.c b/src/timer.c index c92ebc2..9c3c0a9 100644 --- a/src/timer.c +++ b/src/timer.c @@ -33,6 +33,8 @@ u16 pmtimer_ioport VARFSEG; u32 pmtimer_wraps VARLOW; u32 pmtimer_last VARLOW; +u8 ShiftTSC VARFSEG; + void timer_setup(void) { @@ -76,21 +78,25 @@ timer_setup(void) u64 diff = end - start; dprintf(6, "tsc calibrate start=%u end=%u diff=%u\n" , (u32)start, (u32)end, (u32)diff); - u32 t = DIV_ROUND_UP(diff * PMTIMER_HZ, CALIBRATE_COUNT); - TimerKHz = DIV_ROUND_UP(t, 1000 * PMTIMER_TO_PIT); + u64 t = DIV_ROUND_UP(diff * PMTIMER_HZ, CALIBRATE_COUNT); + while (t >= (1<<24)) { + ShiftTSC++; + t = (t + 1) >> 1; + } + TimerKHz = DIV_ROUND_UP((u32)t, 1000 * PMTIMER_TO_PIT); - dprintf(1, "CPU Mhz=%u\n", t / (1000000 * PMTIMER_TO_PIT)); + dprintf(1, "CPU Mhz=%u\n", (TimerKHz << ShiftTSC) / 1000); } /* TSC emulation timekeepers */ -u64 TSC_8254 VARLOW; +u32 TSC_8254 VARLOW; int Last_TSC_8254 VARLOW; -static u64 +static u32 emulate_tsc(void) { /* read timer 0 current count */ - u64 ret = GET_LOW(TSC_8254); + u32 ret = GET_LOW(TSC_8254); /* readback mode has slightly shifted registers, works on all * 8254, readback PIT0 latch */ outb(PM_SEL_READBACK | PM_READ_VALUE | PM_READ_COUNTER0, PORT_PIT_MODE); @@ -112,7 +118,7 @@ void pmtimer_setup(u16 ioport) TimerKHz = DIV_ROUND_UP(PMTIMER_HZ, 1000); } -static u64 pmtimer_get(void) +static u32 pmtimer_get(void) { u16 ioport = GET_GLOBAL(pmtimer_ioport); u32 wraps = GET_LOW(pmtimer_wraps); @@ -125,39 +131,39 @@ static u64 pmtimer_get(void) SET_LOW(pmtimer_last, pmtimer); dprintf(9, "pmtimer: %u:%u\n", wraps, pmtimer); - return (u64)wraps << 24 | pmtimer; + return wraps << 24 | pmtimer; } -static u64 +static u32 get_tsc(void) { if (unlikely(GET_GLOBAL(no_tsc))) return emulate_tsc(); if (CONFIG_PMTIMER && GET_GLOBAL(pmtimer_ioport)) return pmtimer_get(); - return rdtscll(); + return rdtscll() >> GET_GLOBAL(ShiftTSC); } int -check_tsc(u64 end) +check_tsc(u32 end) { - return (s64)(get_tsc() - end) > 0; + return (s32)(get_tsc() - end) > 0; } static void -tscdelay(u64 diff) +tscdelay(u32 diff) { - u64 start = get_tsc(); - u64 end = start + diff; + u32 start = get_tsc(); + u32 end = start + diff; while (!check_tsc(end)) cpu_relax(); } static void -tscsleep(u64 diff) +tscsleep(u32 diff) { - u64 start = get_tsc(); - u64 end = start + diff; + u32 start = get_tsc(); + u32 end = start + diff; while (!check_tsc(end)) yield(); } @@ -183,17 +189,15 @@ void msleep(u32 count) { } // Return the TSC value that is 'msecs' time in the future. -u64 +u32 calc_future_tsc(u32 msecs) { - u32 khz = GET_GLOBAL(TimerKHz); - return get_tsc() + ((u64)khz * msecs); + return get_tsc() + (GET_GLOBAL(TimerKHz) * msecs); } -u64 +u32 calc_future_tsc_usec(u32 usecs) { - u32 khz = GET_GLOBAL(TimerKHz); - return get_tsc() + ((u64)DIV_ROUND_UP(khz, 1000) * usecs); + return get_tsc() + DIV_ROUND_UP(GET_GLOBAL(TimerKHz) * usecs, 1000); } |