freebsd-dev/sys/i386/include/clock.h
Poul-Henning Kamp d1b40f007d i386/i386/tsc.c was repo-copied from i386/isa/clock.c.
Remove all the stuff that does not relate to the TSC.

Change the calibration to use DELAY(1000000) rather than trying to check
it against the CMOS RTC, this drastically increases precision:

Using 25 samples on a Athlon 700MHz UP machine I find:

                stddev          min          max        average
CMOS             22200 Hz    -74980 Hz     34301 Hz   704928721 Hz
DELAY             1805 Hz     -1984 Hz      2678 Hz   704937583 Hz

(The difference between the two averages is not statistically significant.)

expressed in PPM of the frequency:
                stddev          min          max
CMOS             31.49 PPM  -106.37 PPM    48.66 PPM
DELAY             2.56 PPM     2.81 PPM     3.80 PPM

This code will not be used until a followup commit to sys/isa/clock.c
and sys/pc98/pc98/clock.c which will only happen after some field testing.
2003-02-05 09:20:40 +00:00

53 lines
1.1 KiB
C

/*
* Kernel interface to machine-dependent clock driver.
* Garrett Wollman, September 1994.
* This file is in the public domain.
*
* $FreeBSD$
*/
#ifndef _MACHINE_CLOCK_H_
#define _MACHINE_CLOCK_H_
#ifdef _KERNEL
/*
* i386 to clock driver interface.
* XXX large parts of the driver and its interface are misplaced.
*/
extern int adjkerntz;
extern int disable_rtc_set;
extern int pscnt;
extern int psdiv;
extern int statclock_disable;
extern u_int timer_freq;
extern int timer0_max_count;
extern uint64_t tsc_freq;
extern int tsc_is_broken;
extern int wall_cmos_clock;
#ifdef APIC_IO
extern int apic_8254_intr;
#endif
/*
* Driver to clock driver interface.
*/
struct clockframe;
int acquire_timer0(int rate, void (*function)(struct clockframe *frame));
int acquire_timer2(int mode);
int release_timer0(void);
int release_timer2(void);
#ifndef PC98
int rtcin(int val);
#else
int acquire_timer1(int mode);
int release_timer1(void);
#endif
int sysbeep(int pitch, int period);
void timer_restore(void);
void init_TSC(void);
#endif /* _KERNEL */
#endif /* !_MACHINE_CLOCK_H_ */