1/* 2 * linux/arch/m68knommu/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/errno.h> 14#include <linux/module.h> 15#include <linux/sched.h> 16#include <linux/kernel.h> 17#include <linux/param.h> 18#include <linux/string.h> 19#include <linux/mm.h> 20#include <linux/profile.h> 21#include <linux/time.h> 22#include <linux/timex.h> 23 24#include <asm/machdep.h> 25#include <asm/io.h> 26#include <asm/irq_regs.h> 27 28#define TICK_SIZE (tick_nsec / 1000) 29 30 31static inline int set_rtc_mmss(unsigned long nowtime) 32{ 33 if (mach_set_clock_mmss) 34 return mach_set_clock_mmss (nowtime); 35 return -1; 36} 37 38/* 39 * timer_interrupt() needs to keep up the real-time clock, 40 * as well as call the "do_timer()" routine every clocktick 41 */ 42static irqreturn_t timer_interrupt(int irq, void *dummy) 43{ 44 /* last time the cmos clock got updated */ 45 static long last_rtc_update=0; 46 47 /* may need to kick the hardware timer */ 48 if (mach_tick) 49 mach_tick(); 50 51 write_seqlock(&xtime_lock); 52 53 do_timer(1); 54#ifndef CONFIG_SMP 55 update_process_times(user_mode(get_irq_regs())); 56#endif 57 if (current->pid) 58 profile_tick(CPU_PROFILING); 59 60 /* 61 * If we have an externally synchronized Linux clock, then update 62 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be 63 * called as close as possible to 500 ms before the new second starts. 64 */ 65 if (ntp_synced() && 66 xtime.tv_sec > last_rtc_update + 660 && 67 (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 && 68 (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) { 69 if (set_rtc_mmss(xtime.tv_sec) == 0) 70 last_rtc_update = xtime.tv_sec; 71 else 72 last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */ 73 } 74#ifdef CONFIG_HEARTBEAT 75 /* use power LED as a heartbeat instead -- much more useful 76 for debugging -- based on the version for PReP by Cort */ 77 /* acts like an actual heart beat -- ie thump-thump-pause... */ 78 if (mach_heartbeat) { 79 static unsigned cnt = 0, period = 0, dist = 0; 80 81 if (cnt == 0 || cnt == dist) 82 mach_heartbeat( 1 ); 83 else if (cnt == 7 || cnt == dist+7) 84 mach_heartbeat( 0 ); 85 86 if (++cnt > period) { 87 cnt = 0; 88 /* The hyperbolic function below modifies the heartbeat period 89 * length in dependency of the current (5min) load. It goes 90 * through the points f(0)=126, f(1)=86, f(5)=51, 91 * f(inf)->30. */ 92 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30; 93 dist = period / 4; 94 } 95 } 96#endif /* CONFIG_HEARTBEAT */ 97 98 write_sequnlock(&xtime_lock); 99 return(IRQ_HANDLED); 100} 101 102void time_init(void) 103{ 104 unsigned int year, mon, day, hour, min, sec; 105 106 extern void arch_gettod(int *year, int *mon, int *day, int *hour, 107 int *min, int *sec); 108 109 arch_gettod(&year, &mon, &day, &hour, &min, &sec); 110 111 if ((year += 1900) < 1970) 112 year += 100; 113 xtime.tv_sec = mktime(year, mon, day, hour, min, sec); 114 xtime.tv_nsec = 0; 115 wall_to_monotonic.tv_sec = -xtime.tv_sec; 116 117 mach_sched_init(timer_interrupt); 118} 119 120/* 121 * This version of gettimeofday has near microsecond resolution. 122 */ 123void do_gettimeofday(struct timeval *tv) 124{ 125 unsigned long flags; 126 unsigned long seq; 127 unsigned long usec, sec; 128 129 do { 130 seq = read_seqbegin_irqsave(&xtime_lock, flags); 131 usec = mach_gettimeoffset ? mach_gettimeoffset() : 0; 132 sec = xtime.tv_sec; 133 usec += (xtime.tv_nsec / 1000); 134 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); 135 136 while (usec >= 1000000) { 137 usec -= 1000000; 138 sec++; 139 } 140 141 tv->tv_sec = sec; 142 tv->tv_usec = usec; 143} 144 145EXPORT_SYMBOL(do_gettimeofday); 146 147int do_settimeofday(struct timespec *tv) 148{ 149 time_t wtm_sec, sec = tv->tv_sec; 150 long wtm_nsec, nsec = tv->tv_nsec; 151 152 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) 153 return -EINVAL; 154 155 write_seqlock_irq(&xtime_lock); 156 /* 157 * This is revolting. We need to set the xtime.tv_usec 158 * correctly. However, the value in this location is 159 * is value at the last tick. 160 * Discover what correction gettimeofday 161 * would have done, and then undo it! 162 */ 163 if (mach_gettimeoffset) 164 nsec -= (mach_gettimeoffset() * 1000); 165 166 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); 167 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); 168 169 set_normalized_timespec(&xtime, sec, nsec); 170 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); 171 172 ntp_clear(); 173 write_sequnlock_irq(&xtime_lock); 174 clock_was_set(); 175 return 0; 176} 177EXPORT_SYMBOL(do_settimeofday); 178