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 <tglx@linutronix.de>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
diff --git a/arch/x86/kernel/time_64.c b/arch/x86/kernel/time_64.c
index 2db4d69..e97a3ee 100644
--- a/arch/x86/kernel/time_64.c
+++ b/arch/x86/kernel/time_64.c
@@ -292,35 +292,6 @@
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 @@
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 &&