| #endif␊ |
| ␊ |
| /*␊ |
| * timeRDTSC()␊ |
| * This routine sets up PIT counter 2 to count down 1/20 of a second.␊ |
| * It pauses until the value is latched in the counter␊ |
| * and then reads the time stamp counter to return to the caller.␊ |
| */␊ |
| uint64_t timeRDTSC(void)␊ |
| {␊ |
| int␉␉attempts = 0;␊ |
| uint64_t latchTime;␊ |
| uint64_t␉saveTime,intermediate;␊ |
| unsigned int timerValue, lastValue;␊ |
| //boolean_t␉int_enabled;␊ |
| /*␊ |
| * Table of correction factors to account for␊ |
| *␉ - timer counter quantization errors, and␊ |
| *␉ - undercounts 0..5␊ |
| */␊ |
| #define SAMPLE_CLKS_EXACT␉(((double) CLKNUM) / 20.0)␊ |
| #define SAMPLE_CLKS_INT␉␉((int) CLKNUM / 20)␊ |
| #define SAMPLE_NSECS␉␉(2000000000LL)␊ |
| #define SAMPLE_MULTIPLIER␉(((double)SAMPLE_NSECS)*SAMPLE_CLKS_EXACT)␊ |
| #define ROUND64(x)␉␉((uint64_t)((x) + 0.5))␊ |
| uint64_t␉scale[6] = {␊ |
| ␉␉ROUND64(SAMPLE_MULTIPLIER/(double)(SAMPLE_CLKS_INT-0)), ␊ |
| ␉␉ROUND64(SAMPLE_MULTIPLIER/(double)(SAMPLE_CLKS_INT-1)), ␊ |
| ␉␉ROUND64(SAMPLE_MULTIPLIER/(double)(SAMPLE_CLKS_INT-2)), ␊ |
| ␉␉ROUND64(SAMPLE_MULTIPLIER/(double)(SAMPLE_CLKS_INT-3)), ␊ |
| ␉␉ROUND64(SAMPLE_MULTIPLIER/(double)(SAMPLE_CLKS_INT-4)), ␊ |
| ␉␉ROUND64(SAMPLE_MULTIPLIER/(double)(SAMPLE_CLKS_INT-5))␊ |
| };␊ |
| ␊ |
| restart:␊ |
| if (attempts >= 9) // increase to up to 9 attempts.␊ |
| // This will flash-reboot. TODO: Use tscPanic instead.␊ |
| printf("Timestamp counter calibation failed with %d attempts\n", attempts);␊ |
| attempts++;␊ |
| enable_PIT2();␉␉// turn on PIT2␊ |
| set_PIT2(0);␉␉// reset timer 2 to be zero␊ |
| latchTime = rdtsc64();␉// get the time stamp to time ␊ |
| latchTime = get_PIT2(&timerValue) - latchTime; // time how long this takes␊ |
| set_PIT2(SAMPLE_CLKS_INT);␉// set up the timer for (almost) 1/20th a second␊ |
| saveTime = rdtsc64();␉// now time how long a 20th a second is...␊ |
| get_PIT2(&lastValue);␊ |
| get_PIT2(&lastValue);␉// read twice, first value may be unreliable␊ |
| do {␊ |
| ␉␉intermediate = get_PIT2(&timerValue);␊ |
| ␉␉if (timerValue > lastValue) {␊ |
| ␉␉␉// Timer wrapped␊ |
| ␉␉␉set_PIT2(0);␊ |
| ␉␉␉disable_PIT2();␊ |
| ␉␉␉goto restart;␊ |
| ␉␉}␊ |
| ␉␉lastValue = timerValue;␊ |
| } while (timerValue > 5);␊ |
| printf("timerValue␉ %d\n",timerValue);␊ |
| printf("intermediate 0x%016llx\n",intermediate);␊ |
| printf("saveTime␉ 0x%016llx\n",saveTime);␊ |
| ␊ |
| intermediate -= saveTime;␉␉// raw count for about 1/20 second␊ |
| intermediate *= scale[timerValue];␉// rescale measured time spent␊ |
| intermediate /= SAMPLE_NSECS;␉// so its exactly 1/20 a second␊ |
| intermediate += latchTime;␉␉// add on our save fudge␊ |
| ␊ |
| set_PIT2(0);␉␉␉// reset timer 2 to be zero␊ |
| disable_PIT2();␉␉␉// turn off PIT 2␊ |
| ␉␊ |
| return intermediate;␊ |
| }␊ |
| ␊ |
| /*␊ |
| * DFE: Measures the TSC frequency in Hz (64-bit) using the ACPI PM timer␊ |
| */␊ |
| static uint64_t measure_tsc_frequency(void)␊ |
|
| ␉}␊ |
| ␉␊ |
| ␉tscFrequency = measure_tsc_frequency();␊ |
| ␉/* if usual method failed */␊ |
| ␉if ( tscFrequency < 1000 )␊ |
| ␉{␊ |
| ␉tscFrequency = timeRDTSC() * 20;␊ |
| ␉}␊ |
| ␉fsbFrequency = 0;␊ |
| ␉cpuFrequency = 0;␊ |
| ␉␊ |
