1/* $Id: time.c,v 1.1.1.1 2007/08/03 18:51:42 Exp $ 2 * 3 * linux/arch/cris/kernel/time.c 4 * 5 * Copyright (C) 1991, 1992, 1995 Linus Torvalds 6 * Copyright (C) 1999, 2000, 2001 Axis Communications AB 7 * 8 * 1994-07-02 Alan Modra 9 * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime 10 * 1995-03-26 Markus Kuhn 11 * fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887 12 * precision CMOS clock update 13 * 1996-05-03 Ingo Molnar 14 * fixed time warps in do_[slow|fast]_gettimeoffset() 15 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 16 * "A Kernel Model for Precision Timekeeping" by Dave Mills 17 * 18 * Linux/CRIS specific code: 19 * 20 * Authors: Bjorn Wesen 21 * Johan Adolfsson 22 * 23 */ 24 25#include <asm/rtc.h> 26#include <linux/errno.h> 27#include <linux/module.h> 28#include <linux/param.h> 29#include <linux/jiffies.h> 30#include <linux/bcd.h> 31#include <linux/timex.h> 32#include <linux/init.h> 33#include <linux/profile.h> 34#include <linux/sched.h> /* just for sched_clock() - funny that */ 35 36int have_rtc; /* used to remember if we have an RTC or not */; 37 38#define TICK_SIZE tick 39 40extern unsigned long loops_per_jiffy; /* init/main.c */ 41unsigned long loops_per_usec; 42 43extern unsigned long do_slow_gettimeoffset(void); 44static unsigned long (*do_gettimeoffset)(void) = do_slow_gettimeoffset; 45 46/* 47 * This version of gettimeofday has near microsecond resolution. 48 * 49 * Note: Division is quite slow on CRIS and do_gettimeofday is called 50 * rather often. Maybe we should do some kind of approximation here 51 * (a naive approximation would be to divide by 1024). 52 */ 53void do_gettimeofday(struct timeval *tv) 54{ 55 unsigned long flags; 56 signed long usec, sec; 57 local_irq_save(flags); 58 usec = do_gettimeoffset(); 59 60 /* 61 * If time_adjust is negative then NTP is slowing the clock 62 * so make sure not to go into next possible interval. 63 * Better to lose some accuracy than have time go backwards.. 64 */ 65 if (unlikely(time_adjust < 0) && usec > tickadj) 66 usec = tickadj; 67 68 sec = xtime.tv_sec; 69 usec += xtime.tv_nsec / 1000; 70 local_irq_restore(flags); 71 72 while (usec >= 1000000) { 73 usec -= 1000000; 74 sec++; 75 } 76 77 tv->tv_sec = sec; 78 tv->tv_usec = usec; 79} 80 81EXPORT_SYMBOL(do_gettimeofday); 82 83int do_settimeofday(struct timespec *tv) 84{ 85 time_t wtm_sec, sec = tv->tv_sec; 86 long wtm_nsec, nsec = tv->tv_nsec; 87 88 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) 89 return -EINVAL; 90 91 write_seqlock_irq(&xtime_lock); 92 /* 93 * This is revolting. We need to set "xtime" correctly. However, the 94 * value in this location is the value at the most recent update of 95 * wall time. Discover what correction gettimeofday() would have 96 * made, and then undo it! 97 */ 98 nsec -= do_gettimeoffset() * NSEC_PER_USEC; 99 100 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); 101 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); 102 103 set_normalized_timespec(&xtime, sec, nsec); 104 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); 105 106 ntp_clear(); 107 write_sequnlock_irq(&xtime_lock); 108 clock_was_set(); 109 return 0; 110} 111 112EXPORT_SYMBOL(do_settimeofday); 113 114 115/* 116 * BUG: This routine does not handle hour overflow properly; it just 117 * sets the minutes. Usually you'll only notice that after reboot! 118 */ 119 120int set_rtc_mmss(unsigned long nowtime) 121{ 122 int retval = 0; 123 int real_seconds, real_minutes, cmos_minutes; 124 125 printk(KERN_DEBUG "set_rtc_mmss(%lu)\n", nowtime); 126 127 if(!have_rtc) 128 return 0; 129 130 cmos_minutes = CMOS_READ(RTC_MINUTES); 131 BCD_TO_BIN(cmos_minutes); 132 133 /* 134 * since we're only adjusting minutes and seconds, 135 * don't interfere with hour overflow. This avoids 136 * messing with unknown time zones but requires your 137 * RTC not to be off by more than 15 minutes 138 */ 139 real_seconds = nowtime % 60; 140 real_minutes = nowtime / 60; 141 if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1) 142 real_minutes += 30; /* correct for half hour time zone */ 143 real_minutes %= 60; 144 145 if (abs(real_minutes - cmos_minutes) < 30) { 146 BIN_TO_BCD(real_seconds); 147 BIN_TO_BCD(real_minutes); 148 CMOS_WRITE(real_seconds,RTC_SECONDS); 149 CMOS_WRITE(real_minutes,RTC_MINUTES); 150 } else { 151 printk(KERN_WARNING 152 "set_rtc_mmss: can't update from %d to %d\n", 153 cmos_minutes, real_minutes); 154 retval = -1; 155 } 156 157 return retval; 158} 159 160/* grab the time from the RTC chip */ 161 162unsigned long 163get_cmos_time(void) 164{ 165 unsigned int year, mon, day, hour, min, sec; 166 167 sec = CMOS_READ(RTC_SECONDS); 168 min = CMOS_READ(RTC_MINUTES); 169 hour = CMOS_READ(RTC_HOURS); 170 day = CMOS_READ(RTC_DAY_OF_MONTH); 171 mon = CMOS_READ(RTC_MONTH); 172 year = CMOS_READ(RTC_YEAR); 173 174 printk(KERN_DEBUG 175 "rtc: sec 0x%x min 0x%x hour 0x%x day 0x%x mon 0x%x year 0x%x\n", 176 sec, min, hour, day, mon, year); 177 178 BCD_TO_BIN(sec); 179 BCD_TO_BIN(min); 180 BCD_TO_BIN(hour); 181 BCD_TO_BIN(day); 182 BCD_TO_BIN(mon); 183 BCD_TO_BIN(year); 184 185 if ((year += 1900) < 1970) 186 year += 100; 187 188 return mktime(year, mon, day, hour, min, sec); 189} 190 191/* update xtime from the CMOS settings. used when /dev/rtc gets a SET_TIME. 192 * TODO: this doesn't reset the fancy NTP phase stuff as do_settimeofday does. 193 */ 194 195void 196update_xtime_from_cmos(void) 197{ 198 if(have_rtc) { 199 xtime.tv_sec = get_cmos_time(); 200 xtime.tv_nsec = 0; 201 } 202} 203 204extern void cris_profile_sample(struct pt_regs* regs); 205 206void 207cris_do_profile(struct pt_regs* regs) 208{ 209 210#if CONFIG_SYSTEM_PROFILER 211 cris_profile_sample(regs); 212#endif 213 214#if CONFIG_PROFILING 215 profile_tick(CPU_PROFILING, regs); 216#endif 217} 218 219static int 220__init init_udelay(void) 221{ 222 loops_per_usec = (loops_per_jiffy * HZ) / 1000000; 223 return 0; 224} 225 226__initcall(init_udelay); 227