From d371698efd45c3664fd1726780c360f02e1f9580 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 12 Oct 2007 23:04:06 +0200 Subject: x86_64: Consolidate tsc calibration Move the TSC calibration code to tsc.c. Reimplement it so the pm timer can be used as a reference as well. Signed-off-by: Thomas Gleixner Signed-off-by: Chris Wright Signed-off-by: Ingo Molnar Signed-off-by: Arjan van de Ven --- arch/x86/kernel/time_64.c | 33 ++------------------------------- 1 file changed, 2 insertions(+), 31 deletions(-) (limited to 'arch/x86/kernel/time_64.c') diff --git a/arch/x86/kernel/time_64.c b/arch/x86/kernel/time_64.c index 2db4d698a2d3..e97a3ee13551 100644 --- a/arch/x86/kernel/time_64.c +++ b/arch/x86/kernel/time_64.c @@ -292,35 +292,6 @@ static unsigned int __init tsc_calibrate_cpu_khz(void) return pmc_now * tsc_khz / (tsc_now - tsc_start); } -/* - * pit_calibrate_tsc() uses the speaker output (channel 2) of - * the PIT. This is better than using the timer interrupt output, - * because we can read the value of the speaker with just one inb(), - * where we need three i/o operations for the interrupt channel. - * We count how many ticks the TSC does in 50 ms. - */ - -static unsigned int __init pit_calibrate_tsc(void) -{ - unsigned long start, end; - unsigned long flags; - - spin_lock_irqsave(&i8253_lock, flags); - - outb((inb(0x61) & ~0x02) | 0x01, 0x61); - - outb(0xb0, 0x43); - outb((PIT_TICK_RATE / (1000 / 50)) & 0xff, 0x42); - outb((PIT_TICK_RATE / (1000 / 50)) >> 8, 0x42); - start = get_cycles_sync(); - while ((inb(0x61) & 0x20) == 0); - end = get_cycles_sync(); - - spin_unlock_irqrestore(&i8253_lock, flags); - - return (end - start) / 50; -} - #define PIT_MODE 0x43 #define PIT_CH0 0x40 @@ -376,14 +347,14 @@ void __init time_init(void) if (hpet_use_timer) { /* set tick_nsec to use the proper rate for HPET */ tick_nsec = TICK_NSEC_HPET; - tsc_khz = hpet_calibrate_tsc(); timename = "HPET"; } else { pit_init(); - tsc_khz = pit_calibrate_tsc(); timename = "PIT"; } + tsc_calibrate(); + cpu_khz = tsc_khz; if (cpu_has(&boot_cpu_data, X86_FEATURE_CONSTANT_TSC) && boot_cpu_data.x86_vendor == X86_VENDOR_AMD && -- cgit v1.2.2