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https://github.com/edk2-porting/linux-next.git
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x86: apic copy calibrate_APIC_clock to each other in apic_32/64.c
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Yinghai Lu
Ingo Molnar
parent
dc1528dd86
commit
2f04fa888d
@ -424,6 +424,90 @@ static void __cpuinit setup_APIC_timer(void)
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clockevents_register_device(levt);
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clockevents_register_device(levt);
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}
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}
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#ifdef CONFIG_X86_64
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/*
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* In this function we calibrate APIC bus clocks to the external
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* timer. Unfortunately we cannot use jiffies and the timer irq
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* to calibrate, since some later bootup code depends on getting
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* the first irq? Ugh.
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*
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* We want to do the calibration only once since we
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* want to have local timer irqs syncron. CPUs connected
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* by the same APIC bus have the very same bus frequency.
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* And we want to have irqs off anyways, no accidental
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* APIC irq that way.
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*/
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#define TICK_COUNT 100000000
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static int __init calibrate_APIC_clock(void)
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{
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unsigned apic, apic_start;
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unsigned long tsc, tsc_start;
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int result;
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local_irq_disable();
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/*
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* Put whatever arbitrary (but long enough) timeout
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* value into the APIC clock, we just want to get the
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* counter running for calibration.
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*
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* No interrupt enable !
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*/
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__setup_APIC_LVTT(250000000, 0, 0);
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apic_start = apic_read(APIC_TMCCT);
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#ifdef CONFIG_X86_PM_TIMER
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if (apic_calibrate_pmtmr && pmtmr_ioport) {
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pmtimer_wait(5000); /* 5ms wait */
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apic = apic_read(APIC_TMCCT);
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result = (apic_start - apic) * 1000L / 5;
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} else
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#endif
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{
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rdtscll(tsc_start);
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do {
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apic = apic_read(APIC_TMCCT);
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rdtscll(tsc);
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} while ((tsc - tsc_start) < TICK_COUNT &&
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(apic_start - apic) < TICK_COUNT);
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result = (apic_start - apic) * 1000L * tsc_khz /
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(tsc - tsc_start);
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}
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local_irq_enable();
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printk(KERN_DEBUG "APIC timer calibration result %d\n", result);
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printk(KERN_INFO "Detected %d.%03d MHz APIC timer.\n",
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result / 1000 / 1000, result / 1000 % 1000);
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/* Calculate the scaled math multiplication factor */
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lapic_clockevent.mult = div_sc(result, NSEC_PER_SEC,
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lapic_clockevent.shift);
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lapic_clockevent.max_delta_ns =
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clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
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lapic_clockevent.min_delta_ns =
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clockevent_delta2ns(0xF, &lapic_clockevent);
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calibration_result = (result * APIC_DIVISOR) / HZ;
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/*
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* Do a sanity check on the APIC calibration result
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*/
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if (calibration_result < (1000000 / HZ)) {
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printk(KERN_WARNING
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"APIC frequency too slow, disabling apic timer\n");
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return -1;
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}
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return 0;
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}
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#else
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/*
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/*
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* In this functions we calibrate APIC bus clocks to the external timer.
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* In this functions we calibrate APIC bus clocks to the external timer.
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*
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*
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@ -635,6 +719,8 @@ static int __init calibrate_APIC_clock(void)
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return 0;
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return 0;
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}
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}
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#endif
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/*
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/*
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* Setup the boot APIC
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* Setup the boot APIC
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*
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*
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@ -478,6 +478,7 @@ static void __cpuinit setup_APIC_timer(void)
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clockevents_register_device(levt);
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clockevents_register_device(levt);
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}
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}
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#ifdef CONFIG_X86_64
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/*
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/*
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* In this function we calibrate APIC bus clocks to the external
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* In this function we calibrate APIC bus clocks to the external
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* timer. Unfortunately we cannot use jiffies and the timer irq
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* timer. Unfortunately we cannot use jiffies and the timer irq
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@ -560,6 +561,220 @@ static int __init calibrate_APIC_clock(void)
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return 0;
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return 0;
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}
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}
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#else
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/*
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* In this functions we calibrate APIC bus clocks to the external timer.
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*
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* We want to do the calibration only once since we want to have local timer
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* irqs syncron. CPUs connected by the same APIC bus have the very same bus
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* frequency.
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*
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* This was previously done by reading the PIT/HPET and waiting for a wrap
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* around to find out, that a tick has elapsed. I have a box, where the PIT
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* readout is broken, so it never gets out of the wait loop again. This was
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* also reported by others.
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*
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* Monitoring the jiffies value is inaccurate and the clockevents
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* infrastructure allows us to do a simple substitution of the interrupt
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* handler.
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*
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* The calibration routine also uses the pm_timer when possible, as the PIT
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* happens to run way too slow (factor 2.3 on my VAIO CoreDuo, which goes
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* back to normal later in the boot process).
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*/
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#define LAPIC_CAL_LOOPS (HZ/10)
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static __initdata int lapic_cal_loops = -1;
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static __initdata long lapic_cal_t1, lapic_cal_t2;
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static __initdata unsigned long long lapic_cal_tsc1, lapic_cal_tsc2;
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static __initdata unsigned long lapic_cal_pm1, lapic_cal_pm2;
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static __initdata unsigned long lapic_cal_j1, lapic_cal_j2;
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/*
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* Temporary interrupt handler.
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*/
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static void __init lapic_cal_handler(struct clock_event_device *dev)
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{
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unsigned long long tsc = 0;
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long tapic = apic_read(APIC_TMCCT);
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unsigned long pm = acpi_pm_read_early();
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if (cpu_has_tsc)
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rdtscll(tsc);
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switch (lapic_cal_loops++) {
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case 0:
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lapic_cal_t1 = tapic;
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lapic_cal_tsc1 = tsc;
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lapic_cal_pm1 = pm;
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lapic_cal_j1 = jiffies;
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break;
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case LAPIC_CAL_LOOPS:
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lapic_cal_t2 = tapic;
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lapic_cal_tsc2 = tsc;
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if (pm < lapic_cal_pm1)
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pm += ACPI_PM_OVRRUN;
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lapic_cal_pm2 = pm;
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lapic_cal_j2 = jiffies;
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break;
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}
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}
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static int __init calibrate_APIC_clock(void)
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{
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struct clock_event_device *levt = &__get_cpu_var(lapic_events);
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const long pm_100ms = PMTMR_TICKS_PER_SEC/10;
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const long pm_thresh = pm_100ms/100;
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void (*real_handler)(struct clock_event_device *dev);
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unsigned long deltaj;
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long delta, deltapm;
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int pm_referenced = 0;
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local_irq_disable();
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/* Replace the global interrupt handler */
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real_handler = global_clock_event->event_handler;
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global_clock_event->event_handler = lapic_cal_handler;
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/*
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* Setup the APIC counter to 1e9. There is no way the lapic
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* can underflow in the 100ms detection time frame
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*/
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__setup_APIC_LVTT(1000000000, 0, 0);
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/* Let the interrupts run */
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local_irq_enable();
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while (lapic_cal_loops <= LAPIC_CAL_LOOPS)
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cpu_relax();
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local_irq_disable();
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/* Restore the real event handler */
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global_clock_event->event_handler = real_handler;
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/* Build delta t1-t2 as apic timer counts down */
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delta = lapic_cal_t1 - lapic_cal_t2;
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apic_printk(APIC_VERBOSE, "... lapic delta = %ld\n", delta);
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/* Check, if the PM timer is available */
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deltapm = lapic_cal_pm2 - lapic_cal_pm1;
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apic_printk(APIC_VERBOSE, "... PM timer delta = %ld\n", deltapm);
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if (deltapm) {
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unsigned long mult;
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u64 res;
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mult = clocksource_hz2mult(PMTMR_TICKS_PER_SEC, 22);
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if (deltapm > (pm_100ms - pm_thresh) &&
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deltapm < (pm_100ms + pm_thresh)) {
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apic_printk(APIC_VERBOSE, "... PM timer result ok\n");
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} else {
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res = (((u64) deltapm) * mult) >> 22;
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do_div(res, 1000000);
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printk(KERN_WARNING "APIC calibration not consistent "
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"with PM Timer: %ldms instead of 100ms\n",
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(long)res);
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/* Correct the lapic counter value */
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res = (((u64) delta) * pm_100ms);
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do_div(res, deltapm);
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printk(KERN_INFO "APIC delta adjusted to PM-Timer: "
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"%lu (%ld)\n", (unsigned long) res, delta);
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delta = (long) res;
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}
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pm_referenced = 1;
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}
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/* Calculate the scaled math multiplication factor */
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lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
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lapic_clockevent.shift);
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lapic_clockevent.max_delta_ns =
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clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
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lapic_clockevent.min_delta_ns =
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clockevent_delta2ns(0xF, &lapic_clockevent);
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calibration_result = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS;
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apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta);
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apic_printk(APIC_VERBOSE, "..... mult: %ld\n", lapic_clockevent.mult);
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apic_printk(APIC_VERBOSE, "..... calibration result: %u\n",
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calibration_result);
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if (cpu_has_tsc) {
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delta = (long)(lapic_cal_tsc2 - lapic_cal_tsc1);
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apic_printk(APIC_VERBOSE, "..... CPU clock speed is "
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"%ld.%04ld MHz.\n",
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(delta / LAPIC_CAL_LOOPS) / (1000000 / HZ),
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(delta / LAPIC_CAL_LOOPS) % (1000000 / HZ));
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}
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apic_printk(APIC_VERBOSE, "..... host bus clock speed is "
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"%u.%04u MHz.\n",
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calibration_result / (1000000 / HZ),
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calibration_result % (1000000 / HZ));
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/*
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* Do a sanity check on the APIC calibration result
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*/
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if (calibration_result < (1000000 / HZ)) {
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local_irq_enable();
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printk(KERN_WARNING
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"APIC frequency too slow, disabling apic timer\n");
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return -1;
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}
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levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
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/* We trust the pm timer based calibration */
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if (!pm_referenced) {
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apic_printk(APIC_VERBOSE, "... verify APIC timer\n");
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/*
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* Setup the apic timer manually
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*/
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levt->event_handler = lapic_cal_handler;
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lapic_timer_setup(CLOCK_EVT_MODE_PERIODIC, levt);
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lapic_cal_loops = -1;
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/* Let the interrupts run */
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local_irq_enable();
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while (lapic_cal_loops <= LAPIC_CAL_LOOPS)
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cpu_relax();
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local_irq_disable();
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/* Stop the lapic timer */
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lapic_timer_setup(CLOCK_EVT_MODE_SHUTDOWN, levt);
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local_irq_enable();
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/* Jiffies delta */
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deltaj = lapic_cal_j2 - lapic_cal_j1;
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apic_printk(APIC_VERBOSE, "... jiffies delta = %lu\n", deltaj);
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/* Check, if the jiffies result is consistent */
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if (deltaj >= LAPIC_CAL_LOOPS-2 && deltaj <= LAPIC_CAL_LOOPS+2)
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apic_printk(APIC_VERBOSE, "... jiffies result ok\n");
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else
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levt->features |= CLOCK_EVT_FEAT_DUMMY;
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} else
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local_irq_enable();
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if (levt->features & CLOCK_EVT_FEAT_DUMMY) {
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printk(KERN_WARNING
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"APIC timer disabled due to verification failure.\n");
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return -1;
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}
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return 0;
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}
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#endif
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/*
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/*
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* Setup the boot APIC
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* Setup the boot APIC
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*
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*
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