Exemple #1
0
static int __init calibrate_APIC_clock(void)
{
	int apic, apic_start, tsc, tsc_start;
	int result;
	u64 wallclock_nsecs;
	/*
	 * Put whatever arbitrary (but long enough) timeout
	 * value into the APIC clock, we just want to get the
	 * counter running for calibration.
	 */
	__setup_APIC_LVTT(1000000000, 0);

	apic_start = apic_read(APIC_TMCCT);
#ifdef CONFIG_X86_PM_TIMER
	if (apic_calibrate_pmtmr && pmtmr_ioport) {
		pmtimer_wait(5000);  /* 5ms wait */
		apic = apic_read(APIC_TMCCT);
		result = (apic_start - apic) * 1000L / 5;
		printk("using pmtimer for lapic calibration\n");
		wallclock_nsecs = 5000000;
	} else
#endif
	{
		rdtscl(tsc_start);

		do {
			apic = apic_read(APIC_TMCCT);
			rdtscl(tsc);
		} while ((tsc - tsc_start) < TICK_COUNT &&
				(apic - apic_start) < TICK_COUNT);

		result = (apic_start - apic) * 1000L * cpu_khz /
					(tsc - tsc_start);
		wallclock_nsecs = ((u64)tsc - (u64)tsc_start) * 1000000 / (u64)cpu_khz;

	}
	printk("result %d\n", result);


	printk(KERN_INFO "Detected %d.%03d MHz APIC timer.\n",
		result / 1000 / 1000, result / 1000 % 1000);




	/* Calculate the scaled math multiplication factor */
	lapic_clockevent.mult = div_sc(apic_start - apic, wallclock_nsecs, 32);

	lapic_clockevent.max_delta_ns =
		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
	printk("lapic max_delta_ns: %ld\n", lapic_clockevent.max_delta_ns);
	lapic_clockevent.min_delta_ns =
		clockevent_delta2ns(0xF, &lapic_clockevent);


	return result * APIC_DIVISOR / HZ;
}
Exemple #2
0
static void __init calibrate_APIC_clock(void)
{
	unsigned apic, apic_start;
	unsigned long tsc, tsc_start;
	int result;

	local_irq_disable();

	/*
	 * Put whatever arbitrary (but long enough) timeout
	 * value into the APIC clock, we just want to get the
	 * counter running for calibration.
	 *
	 * No interrupt enable !
	 */
	__setup_APIC_LVTT(250000000, 0, 0);

	apic_start = apic_read(APIC_TMCCT);
#ifdef CONFIG_X86_PM_TIMER
	if (apic_calibrate_pmtmr && pmtmr_ioport) {
		pmtimer_wait(5000);  /* 5ms wait */
		apic = apic_read(APIC_TMCCT);
		result = (apic_start - apic) * 1000L / 5;
	} else
#endif
	{
		rdtscll(tsc_start);

		do {
			apic = apic_read(APIC_TMCCT);
			rdtscll(tsc);
		} while ((tsc - tsc_start) < TICK_COUNT &&
				(apic_start - apic) < TICK_COUNT);

		result = (apic_start - apic) * 1000L * tsc_khz /
					(tsc - tsc_start);
	}

	local_irq_enable();

	printk(KERN_DEBUG "APIC timer calibration result %d\n", result);

	printk(KERN_INFO "Detected %d.%03d MHz APIC timer.\n",
		result / 1000 / 1000, result / 1000 % 1000);

	/* Calculate the scaled math multiplication factor */
	lapic_clockevent.mult = div_sc(result, NSEC_PER_SEC, 32);
	lapic_clockevent.max_delta_ns =
		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
	lapic_clockevent.min_delta_ns =
		clockevent_delta2ns(0xF, &lapic_clockevent);

	calibration_result = result / HZ;
}
Exemple #3
0
static int __init calibrate_APIC_clock(void)
{
	unsigned apic, apic_start;
	unsigned long tsc, tsc_start;
	int result;
	/*
	 * Put whatever arbitrary (but long enough) timeout
	 * value into the APIC clock, we just want to get the
	 * counter running for calibration.
	 */
	__setup_APIC_LVTT(4000000000);

	apic_start = apic_read(APIC_TMCCT);
#ifdef CONFIG_X86_PM_TIMER
	if (apic_calibrate_pmtmr && pmtmr_ioport) {
		pmtimer_wait(5000);  /* 5ms wait */
		apic = apic_read(APIC_TMCCT);
		result = (apic_start - apic) * 1000L / 5;
	} else
#endif
	{
		rdtscll(tsc_start);

		do {
			apic = apic_read(APIC_TMCCT);
			rdtscll(tsc);
		} while ((tsc - tsc_start) < TICK_COUNT &&
				(apic_start - apic) < TICK_COUNT);

		result = (apic_start - apic) * 1000L * tsc_khz /
					(tsc - tsc_start);
	}
	printk("result %d\n", result);


	printk(KERN_INFO "Detected %d.%03d MHz APIC timer.\n",
		result / 1000 / 1000, result / 1000 % 1000);

	return result * APIC_DIVISOR / HZ;
}