diff options
Diffstat (limited to 'arch/x86/kernel/hpet_64.c')
| -rw-r--r-- | arch/x86/kernel/hpet_64.c | 49 |
1 files changed, 0 insertions, 49 deletions
diff --git a/arch/x86/kernel/hpet_64.c b/arch/x86/kernel/hpet_64.c index e2d1b912e15..1ebce2ec7ea 100644 --- a/arch/x86/kernel/hpet_64.c +++ b/arch/x86/kernel/hpet_64.c @@ -184,55 +184,6 @@ int hpet_reenable(void) return hpet_timer_stop_set_go(hpet_tick); } -/* - * calibrate_tsc() calibrates the processor TSC in a very simple way, comparing - * it to the HPET timer of known frequency. - */ - -#define TICK_COUNT 100000000 -#define SMI_THRESHOLD 50000 -#define MAX_TRIES 5 - -/* - * Some platforms take periodic SMI interrupts with 5ms duration. Make sure none - * occurs between the reads of the hpet & TSC. - */ -static void __init read_hpet_tsc(int *hpet, int *tsc) -{ - int tsc1, tsc2, hpet1, i; - - for (i = 0; i < MAX_TRIES; i++) { - tsc1 = get_cycles_sync(); - hpet1 = hpet_readl(HPET_COUNTER); - tsc2 = get_cycles_sync(); - if ((tsc2 - tsc1) < SMI_THRESHOLD) - break; - } - *hpet = hpet1; - *tsc = tsc2; -} - -unsigned int __init hpet_calibrate_tsc(void) -{ - int tsc_start, hpet_start; - int tsc_now, hpet_now; - unsigned long flags; - - local_irq_save(flags); - - read_hpet_tsc(&hpet_start, &tsc_start); - - do { - local_irq_disable(); - read_hpet_tsc(&hpet_now, &tsc_now); - local_irq_restore(flags); - } while ((tsc_now - tsc_start) < TICK_COUNT && - (hpet_now - hpet_start) < TICK_COUNT); - - return (tsc_now - tsc_start) * 1000000000L - / ((hpet_now - hpet_start) * hpet_period / 1000); -} - #ifdef CONFIG_HPET_EMULATE_RTC /* HPET in LegacyReplacement Mode eats up RTC interrupt line. When, HPET * is enabled, we support RTC interrupt functionality in software. |