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 1.26 1997/05/04 14:25:00 peter Exp $ 7 */ 8 9 #ifndef _MACHINE_CLOCK_H_ 10 #define _MACHINE_CLOCK_H_ 11 12 #if (defined(I586_CPU) || defined(I686_CPU)) && !defined(SMP) 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 #ifndef SMP 33 extern u_int i586_ctr_bias; 34 extern u_int i586_ctr_comultiplier; 35 #endif 36 extern u_int i586_ctr_freq; 37 #ifndef SMP 38 extern u_int i586_ctr_multiplier; 39 #endif 40 #endif 41 extern int statclock_disable; 42 extern u_int timer_freq; 43 extern int timer0_max_count; 44 extern u_int timer0_overflow_threshold; 45 extern u_int timer0_prescaler_count; 46 extern int wall_cmos_clock; 47 48 /* 49 * Driver to clock driver interface. 50 */ 51 struct clockframe; 52 53 void DELAY __P((int usec)); 54 int acquire_timer0 __P((int rate, 55 void (*function)(struct clockframe *frame))); 56 int acquire_timer2 __P((int mode)); 57 int release_timer0 __P((void)); 58 int release_timer2 __P((void)); 59 #ifndef PC98 60 int rtcin __P((int val)); 61 #else 62 int acquire_timer1 __P((int mode)); 63 int release_timer1 __P((void)); 64 #endif 65 int sysbeep __P((int pitch, int period)); 66 67 #ifdef CLOCK_HAIR 68 69 #ifdef PC98 70 #include <pc98/pc98/pc98.h> /* XXX */ 71 #else 72 #include <i386/isa/isa.h> /* XXX */ 73 #endif 74 #include <i386/isa/timerreg.h> /* XXX */ 75 76 static __inline u_int 77 clock_latency(void) 78 { 79 u_char high, low; 80 81 outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH); 82 low = inb(TIMER_CNTR0); 83 high = inb(TIMER_CNTR0); 84 return (timer0_prescaler_count + timer0_max_count 85 - ((high << 8) | low)); 86 } 87 88 #if (defined(I586_CPU) || defined(I686_CPU)) && !defined(SMP) 89 /* 90 * When we update `time', on i586's we also update `i586_ctr_bias' 91 * atomically. `i586_ctr_bias' is the best available approximation to 92 * the value of the i586 counter (mod 2^32) at the time of the i8254 93 * counter transition that caused the clock interrupt that caused the 94 * update. clock_latency() gives the time between the transition and 95 * the update to within a few usec provided another such transition 96 * hasn't occurred. We don't bother checking for counter overflow as 97 * in microtime(), since if it occurs then we're close to losing clock 98 * interrupts. 99 */ 100 static __inline void 101 cpu_clockupdate(volatile struct timeval *otime, struct timeval *ntime) 102 { 103 if (i586_ctr_freq != 0) { 104 u_int i586_count; /* truncated */ 105 u_int i8254_count; 106 107 disable_intr(); 108 i8254_count = clock_latency(); 109 i586_count = rdtsc(); 110 i586_ctr_bias = i586_count 111 - (u_int) 112 (((unsigned long long)i586_ctr_comultiplier 113 * i8254_count) 114 >> I586_CTR_COMULTIPLIER_SHIFT); 115 *otime = *ntime; 116 enable_intr(); 117 } else 118 *otime = *ntime; 119 } 120 #endif /* I586_CPU || I686_CPU */ 121 122 #endif /* CLOCK_HAIR */ 123 124 #endif /* KERNEL */ 125 126 #endif /* !_MACHINE_CLOCK_H_ */ 127