1 /* 2 * linux/arch/m68k/kernel/time.c 3 * 4 * Copyright (C) 1991, 1992, 1995 Linus Torvalds 5 * 6 * This file contains the m68k-specific time handling details. 7 * Most of the stuff is located in the machine specific files. 8 * 9 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 10 * "A Kernel Model for Precision Timekeeping" by Dave Mills 11 */ 12 13 #include <linux/config.h> /* CONFIG_HEARTBEAT */ 14 #include <linux/errno.h> 15 #include <linux/module.h> 16 #include <linux/sched.h> 17 #include <linux/kernel.h> 18 #include <linux/param.h> 19 #include <linux/string.h> 20 #include <linux/mm.h> 21 #include <linux/rtc.h> 22 23 #include <asm/machdep.h> 24 #include <asm/io.h> 25 26 #include <linux/time.h> 27 #include <linux/timex.h> 28 #include <linux/profile.h> 29 30 u64 jiffies_64 = INITIAL_JIFFIES; 31 32 EXPORT_SYMBOL(jiffies_64); 33 34 static inline int set_rtc_mmss(unsigned long nowtime) 35 { 36 if (mach_set_clock_mmss) 37 return mach_set_clock_mmss (nowtime); 38 return -1; 39 } 40 41 /* 42 * timer_interrupt() needs to keep up the real-time clock, 43 * as well as call the "do_timer()" routine every clocktick 44 */ 45 static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs) 46 { 47 do_timer(regs); 48 #ifndef CONFIG_SMP 49 update_process_times(user_mode(regs)); 50 #endif 51 profile_tick(CPU_PROFILING, regs); 52 53 #ifdef CONFIG_HEARTBEAT 54 /* use power LED as a heartbeat instead -- much more useful 55 for debugging -- based on the version for PReP by Cort */ 56 /* acts like an actual heart beat -- ie thump-thump-pause... */ 57 if (mach_heartbeat) { 58 static unsigned cnt = 0, period = 0, dist = 0; 59 60 if (cnt == 0 || cnt == dist) 61 mach_heartbeat( 1 ); 62 else if (cnt == 7 || cnt == dist+7) 63 mach_heartbeat( 0 ); 64 65 if (++cnt > period) { 66 cnt = 0; 67 /* The hyperbolic function below modifies the heartbeat period 68 * length in dependency of the current (5min) load. It goes 69 * through the points f(0)=126, f(1)=86, f(5)=51, 70 * f(inf)->30. */ 71 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30; 72 dist = period / 4; 73 } 74 } 75 #endif /* CONFIG_HEARTBEAT */ 76 return IRQ_HANDLED; 77 } 78 79 void time_init(void) 80 { 81 struct rtc_time time; 82 83 if (mach_hwclk) { 84 mach_hwclk(0, &time); 85 86 if ((time.tm_year += 1900) < 1970) 87 time.tm_year += 100; 88 xtime.tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday, 89 time.tm_hour, time.tm_min, time.tm_sec); 90 xtime.tv_nsec = 0; 91 } 92 wall_to_monotonic.tv_sec = -xtime.tv_sec; 93 94 mach_sched_init(timer_interrupt); 95 } 96 97 /* 98 * This version of gettimeofday has near microsecond resolution. 99 */ 100 void do_gettimeofday(struct timeval *tv) 101 { 102 unsigned long flags; 103 extern unsigned long wall_jiffies; 104 unsigned long seq; 105 unsigned long usec, sec, lost; 106 unsigned long max_ntp_tick = tick_usec - tickadj; 107 108 do { 109 seq = read_seqbegin_irqsave(&xtime_lock, flags); 110 111 usec = mach_gettimeoffset(); 112 lost = jiffies - wall_jiffies; 113 114 /* 115 * If time_adjust is negative then NTP is slowing the clock 116 * so make sure not to go into next possible interval. 117 * Better to lose some accuracy than have time go backwards.. 118 */ 119 if (unlikely(time_adjust < 0)) { 120 usec = min(usec, max_ntp_tick); 121 122 if (lost) 123 usec += lost * max_ntp_tick; 124 } 125 else if (unlikely(lost)) 126 usec += lost * tick_usec; 127 128 sec = xtime.tv_sec; 129 usec += xtime.tv_nsec/1000; 130 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); 131 132 133 while (usec >= 1000000) { 134 usec -= 1000000; 135 sec++; 136 } 137 138 tv->tv_sec = sec; 139 tv->tv_usec = usec; 140 } 141 142 EXPORT_SYMBOL(do_gettimeofday); 143 144 int do_settimeofday(struct timespec *tv) 145 { 146 time_t wtm_sec, sec = tv->tv_sec; 147 long wtm_nsec, nsec = tv->tv_nsec; 148 extern unsigned long wall_jiffies; 149 150 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) 151 return -EINVAL; 152 153 write_seqlock_irq(&xtime_lock); 154 /* This is revolting. We need to set the xtime.tv_nsec 155 * correctly. However, the value in this location is 156 * is value at the last tick. 157 * Discover what correction gettimeofday 158 * would have done, and then undo it! 159 */ 160 nsec -= 1000 * (mach_gettimeoffset() + 161 (jiffies - wall_jiffies) * (1000000 / HZ)); 162 163 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); 164 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); 165 166 set_normalized_timespec(&xtime, sec, nsec); 167 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); 168 169 time_adjust = 0; /* stop active adjtime() */ 170 time_status |= STA_UNSYNC; 171 time_maxerror = NTP_PHASE_LIMIT; 172 time_esterror = NTP_PHASE_LIMIT; 173 write_sequnlock_irq(&xtime_lock); 174 clock_was_set(); 175 return 0; 176 } 177 178 EXPORT_SYMBOL(do_settimeofday); 179 180 /* 181 * Scheduler clock - returns current time in ns units. 182 */ 183 unsigned long long sched_clock(void) 184 { 185 return (unsigned long long)jiffies*(1000000000/HZ); 186 } 187 188