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/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/rtc.h> 21 #include <linux/platform_device.h> 22 23 #include <asm/machdep.h> 24 #include <asm/io.h> 25 #include <asm/irq_regs.h> 26 27 #include <linux/time.h> 28 #include <linux/timex.h> 29 #include <linux/profile.h> 30 31 static 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 */ 42 static irqreturn_t timer_interrupt(int irq, void *dummy) 43 { 44 do_timer(1); 45 #ifndef CONFIG_SMP 46 update_process_times(user_mode(get_irq_regs())); 47 #endif 48 profile_tick(CPU_PROFILING); 49 50 #ifdef CONFIG_HEARTBEAT 51 /* use power LED as a heartbeat instead -- much more useful 52 for debugging -- based on the version for PReP by Cort */ 53 /* acts like an actual heart beat -- ie thump-thump-pause... */ 54 if (mach_heartbeat) { 55 static unsigned cnt = 0, period = 0, dist = 0; 56 57 if (cnt == 0 || cnt == dist) 58 mach_heartbeat( 1 ); 59 else if (cnt == 7 || cnt == dist+7) 60 mach_heartbeat( 0 ); 61 62 if (++cnt > period) { 63 cnt = 0; 64 /* The hyperbolic function below modifies the heartbeat period 65 * length in dependency of the current (5min) load. It goes 66 * through the points f(0)=126, f(1)=86, f(5)=51, 67 * f(inf)->30. */ 68 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30; 69 dist = period / 4; 70 } 71 } 72 #endif /* CONFIG_HEARTBEAT */ 73 return IRQ_HANDLED; 74 } 75 76 void __init time_init(void) 77 { 78 struct rtc_time time; 79 80 if (mach_hwclk) { 81 mach_hwclk(0, &time); 82 83 if ((time.tm_year += 1900) < 1970) 84 time.tm_year += 100; 85 xtime.tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday, 86 time.tm_hour, time.tm_min, time.tm_sec); 87 xtime.tv_nsec = 0; 88 } 89 wall_to_monotonic.tv_sec = -xtime.tv_sec; 90 91 mach_sched_init(timer_interrupt); 92 } 93 94 /* 95 * This version of gettimeofday has near microsecond resolution. 96 */ 97 void do_gettimeofday(struct timeval *tv) 98 { 99 unsigned long flags; 100 unsigned long seq; 101 unsigned long usec, sec; 102 unsigned long max_ntp_tick = tick_usec - tickadj; 103 104 do { 105 seq = read_seqbegin_irqsave(&xtime_lock, flags); 106 107 usec = mach_gettimeoffset(); 108 109 /* 110 * If time_adjust is negative then NTP is slowing the clock 111 * so make sure not to go into next possible interval. 112 * Better to lose some accuracy than have time go backwards.. 113 */ 114 if (unlikely(time_adjust < 0)) 115 usec = min(usec, max_ntp_tick); 116 117 sec = xtime.tv_sec; 118 usec += xtime.tv_nsec/1000; 119 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); 120 121 122 while (usec >= 1000000) { 123 usec -= 1000000; 124 sec++; 125 } 126 127 tv->tv_sec = sec; 128 tv->tv_usec = usec; 129 } 130 131 EXPORT_SYMBOL(do_gettimeofday); 132 133 int do_settimeofday(struct timespec *tv) 134 { 135 time_t wtm_sec, sec = tv->tv_sec; 136 long wtm_nsec, nsec = tv->tv_nsec; 137 138 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) 139 return -EINVAL; 140 141 write_seqlock_irq(&xtime_lock); 142 /* This is revolting. We need to set the xtime.tv_nsec 143 * correctly. However, the value in this location is 144 * is value at the last tick. 145 * Discover what correction gettimeofday 146 * would have done, and then undo it! 147 */ 148 nsec -= 1000 * mach_gettimeoffset(); 149 150 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); 151 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); 152 153 set_normalized_timespec(&xtime, sec, nsec); 154 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); 155 156 ntp_clear(); 157 write_sequnlock_irq(&xtime_lock); 158 clock_was_set(); 159 return 0; 160 } 161 162 EXPORT_SYMBOL(do_settimeofday); 163 164 165 static int __init rtc_init(void) 166 { 167 struct platform_device *pdev; 168 169 if (!mach_hwclk) 170 return -ENODEV; 171 172 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0); 173 if (IS_ERR(pdev)) 174 return PTR_ERR(pdev); 175 176 return 0; 177 } 178 179 module_init(rtc_init); 180