diff options
Diffstat (limited to 'arch/x86/kernel/apic/apic.c')
| -rw-r--r-- | arch/x86/kernel/apic/apic.c | 33 |
1 files changed, 26 insertions, 7 deletions
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index a2fd72e0ab35..f98d84caf94c 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -186,7 +186,7 @@ static struct resource lapic_resource = { .flags = IORESOURCE_MEM | IORESOURCE_BUSY, }; -static unsigned int calibration_result; +unsigned int lapic_timer_frequency = 0; static void apic_pm_activate(void); @@ -454,7 +454,7 @@ static void lapic_timer_setup(enum clock_event_mode mode, switch (mode) { case CLOCK_EVT_MODE_PERIODIC: case CLOCK_EVT_MODE_ONESHOT: - __setup_APIC_LVTT(calibration_result, + __setup_APIC_LVTT(lapic_timer_frequency, mode != CLOCK_EVT_MODE_PERIODIC, 1); break; case CLOCK_EVT_MODE_UNUSED: @@ -638,6 +638,25 @@ static int __init calibrate_APIC_clock(void) long delta, deltatsc; int pm_referenced = 0; + /** + * check if lapic timer has already been calibrated by platform + * specific routine, such as tsc calibration code. if so, we just fill + * in the clockevent structure and return. + */ + + if (lapic_timer_frequency) { + apic_printk(APIC_VERBOSE, "lapic timer already calibrated %d\n", + lapic_timer_frequency); + lapic_clockevent.mult = div_sc(lapic_timer_frequency/APIC_DIVISOR, + TICK_NSEC, lapic_clockevent.shift); + lapic_clockevent.max_delta_ns = + clockevent_delta2ns(0x7FFFFF, &lapic_clockevent); + lapic_clockevent.min_delta_ns = + clockevent_delta2ns(0xF, &lapic_clockevent); + lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY; + return 0; + } + local_irq_disable(); /* Replace the global interrupt handler */ @@ -679,12 +698,12 @@ static int __init calibrate_APIC_clock(void) lapic_clockevent.min_delta_ns = clockevent_delta2ns(0xF, &lapic_clockevent); - calibration_result = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS; + lapic_timer_frequency = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS; apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta); apic_printk(APIC_VERBOSE, "..... mult: %u\n", lapic_clockevent.mult); apic_printk(APIC_VERBOSE, "..... calibration result: %u\n", - calibration_result); + lapic_timer_frequency); if (cpu_has_tsc) { apic_printk(APIC_VERBOSE, "..... CPU clock speed is " @@ -695,13 +714,13 @@ static int __init calibrate_APIC_clock(void) apic_printk(APIC_VERBOSE, "..... host bus clock speed is " "%u.%04u MHz.\n", - calibration_result / (1000000 / HZ), - calibration_result % (1000000 / HZ)); + lapic_timer_frequency / (1000000 / HZ), + lapic_timer_frequency % (1000000 / HZ)); /* * Do a sanity check on the APIC calibration result */ - if (calibration_result < (1000000 / HZ)) { + if (lapic_timer_frequency < (1000000 / HZ)) { local_irq_enable(); pr_warning("APIC frequency too slow, disabling apic timer\n"); return -1; |
