clock.h revision 21673
1/* 2 * Kernel interface to machine-dependent clock driver. 3 * Garrett Wollman, September 1994. 4 * This file is in the public domain. 5 * 6 * $FreeBSD: head/sys/amd64/include/clock.h 21673 1997-01-14 07:20:47Z jkh $ 7 */ 8 9#ifndef _MACHINE_CLOCK_H_ 10#define _MACHINE_CLOCK_H_ 11 12#if defined(I586_CPU) || defined(I686_CPU) 13#define CPU_CLOCKUPDATE(otime, ntime) cpu_clockupdate((otime), (ntime)) 14#else 15#define CPU_CLOCKUPDATE(otime, ntime) (*(otime) = *(ntime)) 16#endif 17 18#define CPU_THISTICKLEN(dflt) dflt 19 20#define I586_CTR_COMULTIPLIER_SHIFT 20 21#define I586_CTR_MULTIPLIER_SHIFT 32 22 23#ifdef KERNEL 24/* 25 * i386 to clock driver interface. 26 * XXX almost all of it is misplaced. i586 stuff is done in isa/clock.c 27 * and isa stuff is done in i386/microtime.s and i386/support.s. 28 */ 29extern int adjkerntz; 30extern int disable_rtc_set; 31#if defined(I586_CPU) || defined(I686_CPU) 32extern u_int i586_ctr_bias; 33extern u_int i586_ctr_comultiplier; 34extern u_int i586_ctr_freq; 35extern u_int i586_ctr_multiplier; 36#endif 37extern int statclock_disable; 38extern u_int timer_freq; 39extern int timer0_max_count; 40extern u_int timer0_overflow_threshold; 41extern u_int timer0_prescaler_count; 42extern int wall_cmos_clock; 43 44/* 45 * Driver to clock driver interface. 46 */ 47struct clockframe; 48 49void DELAY __P((int usec)); 50int acquire_timer0 __P((int rate, 51 void (*function)(struct clockframe *frame))); 52int acquire_timer2 __P((int mode)); 53int release_timer0 __P((void)); 54int release_timer2 __P((void)); 55#ifndef PC98 56int rtcin __P((int val)); 57#else 58int acquire_timer1 __P((int mode)); 59int release_timer1 __P((void)); 60#endif 61int sysbeep __P((int pitch, int period)); 62 63#ifdef CLOCK_HAIR 64 65#ifdef PC98 66#include <pc98/pc98/pc98.h> /* XXX */ 67#else 68#include <i386/isa/isa.h> /* XXX */ 69#endif 70#include <i386/isa/timerreg.h> /* XXX */ 71 72static __inline u_int 73clock_latency(void) 74{ 75 u_char high, low; 76 77 outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH); 78 low = inb(TIMER_CNTR0); 79 high = inb(TIMER_CNTR0); 80 return (timer0_prescaler_count + timer0_max_count 81 - ((high << 8) | low)); 82} 83 84#if defined(I586_CPU) || defined(I686_CPU) 85/* 86 * When we update `time', on i586's we also update `i586_ctr_bias' 87 * atomically. `i586_ctr_bias' is the best available approximation to 88 * the value of the i586 counter (mod 2^32) at the time of the i8254 89 * counter transition that caused the clock interrupt that caused the 90 * update. clock_latency() gives the time between the transition and 91 * the update to within a few usec provided another such transition 92 * hasn't occurred. We don't bother checking for counter overflow as 93 * in microtime(), since if it occurs then we're close to losing clock 94 * interrupts. 95 */ 96static __inline void 97cpu_clockupdate(volatile struct timeval *otime, struct timeval *ntime) 98{ 99 if (i586_ctr_freq != 0) { 100 u_int i586_count; /* truncated */ 101 u_int i8254_count; 102 103 disable_intr(); 104 i8254_count = clock_latency(); 105 i586_count = rdtsc(); 106 i586_ctr_bias = i586_count 107 - (u_int) 108 (((unsigned long long)i586_ctr_comultiplier 109 * i8254_count) 110 >> I586_CTR_COMULTIPLIER_SHIFT); 111 *otime = *ntime; 112 enable_intr(); 113 } else 114 *otime = *ntime; 115} 116#endif /* I586_CPU || I686_CPU */ 117 118#endif /* CLOCK_HAIR */ 119 120#endif /* KERNEL */ 121 122#endif /* !_MACHINE_CLOCK_H_ */ 123