1 /* 2 * Kernel interface to machine-dependent clock driver. 3 * Garrett Wollman, September 1994. 4 * This file is in the public domain. 5 * 6 * $Id: clock.h,v 1.19 1996/10/17 17:31:25 bde Exp $ 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 */ 29 extern int adjkerntz; 30 extern int disable_rtc_set; 31 #if defined(I586_CPU) || defined(I686_CPU) 32 extern u_int i586_ctr_bias; 33 extern u_int i586_ctr_comultiplier; 34 extern u_int i586_ctr_freq; 35 extern u_int i586_ctr_multiplier; 36 #endif 37 extern int statclock_disable; 38 extern u_int timer_freq; 39 extern int timer0_max_count; 40 extern u_int timer0_overflow_threshold; 41 extern u_int timer0_prescaler_count; 42 extern int wall_cmos_clock; 43 44 /* 45 * Driver to clock driver interface. 46 */ 47 struct clockframe; 48 49 void DELAY __P((int usec)); 50 int acquire_timer0 __P((int rate, 51 void (*function)(struct clockframe *frame))); 52 int acquire_timer2 __P((int mode)); 53 int release_timer0 __P((void)); 54 int release_timer2 __P((void)); 55 #ifndef PC98 56 int rtcin __P((int val)); 57 #else 58 int acquire_timer1 __P((int mode)); 59 int release_timer1 __P((void)); 60 void rtc_serialcombit __P((int i)); 61 void rtc_serialcom __P((int i)); 62 void rtc_outb __P((int val)); 63 #endif 64 int sysbeep __P((int pitch, int period)); 65 66 #ifdef CLOCK_HAIR 67 68 #include <i386/isa/isa.h> /* XXX */ 69 #include <i386/isa/timerreg.h> /* XXX */ 70 71 static __inline u_int 72 clock_latency(void) 73 { 74 u_char high, low; 75 76 outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH); 77 low = inb(TIMER_CNTR0); 78 high = inb(TIMER_CNTR0); 79 return (timer0_prescaler_count + timer0_max_count 80 - ((high << 8) | low)); 81 } 82 83 #if defined(I586_CPU) || defined(I686_CPU) 84 /* 85 * When we update `time', on i586's we also update `i586_ctr_bias' 86 * atomically. `i586_ctr_bias' is the best available approximation to 87 * the value of the i586 counter (mod 2^32) at the time of the i8254 88 * counter transition that caused the clock interrupt that caused the 89 * update. clock_latency() gives the time between the transition and 90 * the update to within a few usec provided another such transition 91 * hasn't occurred. We don't bother checking for counter overflow as 92 * in microtime(), since if it occurs then we're close to losing clock 93 * interrupts. 94 */ 95 static __inline void 96 cpu_clockupdate(volatile struct timeval *otime, struct timeval *ntime) 97 { 98 if (i586_ctr_freq != 0) { 99 u_int i586_count; /* truncated */ 100 u_int i8254_count; 101 102 disable_intr(); 103 i8254_count = clock_latency(); 104 i586_count = rdtsc(); 105 i586_ctr_bias = i586_count 106 - (u_int) 107 (((unsigned long long)i586_ctr_comultiplier 108 * i8254_count) 109 >> I586_CTR_COMULTIPLIER_SHIFT); 110 *otime = *ntime; 111 enable_intr(); 112 } else 113 *otime = *ntime; 114 } 115 #endif /* I586_CPU || I686_CPU */ 116 117 #endif /* CLOCK_HAIR */ 118 119 #endif /* KERNEL */ 120 121 #endif /* !_MACHINE_CLOCK_H_ */ 122