x86: let 64 bit to use 32 bit calibrate_apic_clock

Use the 32-bit APIC calibration code - it's more mature.

Signed-of-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 2 insertions, 86 deletions

diff --git a/arch/x86/kernel/apic.c b/arch/x86/kernel/apic.c
index 6e99af5ce678..ca5ef71f4208 100644
--- a/arch/x86/kernel/apic.c
+++ b/arch/x86/kernel/apic.c
@@ -478,90 +478,6 @@ static void __cpuinit setup_APIC_timer(void)
         clockevents_register_device(levt);
 }
 
-#ifdef CONFIG_X86_64
-/*
- * In this function we calibrate APIC bus clocks to the external
- * timer. Unfortunately we cannot use jiffies and the timer irq
- * to calibrate, since some later bootup code depends on getting
- * the first irq? Ugh.
- *
- * We want to do the calibration only once since we
- * want to have local timer irqs syncron. CPUs connected
- * by the same APIC bus have the very same bus frequency.
- * And we want to have irqs off anyways, no accidental
- * APIC irq that way.
- */
-
-#define TICK_COUNT 100000000
-
-static int __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,
-                                       lapic_clockevent.shift);
-        lapic_clockevent.max_delta_ns =
-                clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
-        lapic_clockevent.min_delta_ns =
-                clockevent_delta2ns(0xF, &lapic_clockevent);
-
-        calibration_result = (result * APIC_DIVISOR) / HZ;
-
-        /*
-         * Do a sanity check on the APIC calibration result
-         */
-        if (calibration_result < (1000000 / HZ)) {
-                printk(KERN_WARNING
-                        "APIC frequency too slow, disabling apic timer\n");
-                return -1;
-        }
-
-        return 0;
-}
-
-#else
 /*
  * In this functions we calibrate APIC bus clocks to the external timer.
  *
@@ -659,6 +575,7 @@ static int __init calibrate_APIC_clock(void)
         delta = lapic_cal_t1 - lapic_cal_t2;
         apic_printk(APIC_VERBOSE, "... lapic delta = %ld\n", delta);
 
+#ifdef CONFIG_X86_PM_TIMER
         /* Check, if the PM timer is available */
         deltapm = lapic_cal_pm2 - lapic_cal_pm1;
         apic_printk(APIC_VERBOSE, "... PM timer delta = %ld\n", deltapm);
@@ -687,6 +604,7 @@ static int __init calibrate_APIC_clock(void)
                 }
                 pm_referenced = 1;
         }
+#endif
 
         /* Calculate the scaled math multiplication factor */
         lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
@@ -773,8 +691,6 @@ static int __init calibrate_APIC_clock(void)
         return 0;
 }
 
-#endif
-
 /*
  * Setup the boot APIC
  *