arch/arm/kernel/time.c

   1 /*
   2  *  linux/arch/arm/kernel/time.c
   3  *
   4  *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
   5  *  Modifications for ARM (C) 1994-2001 Russell King
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  *  This file contains the ARM-specific time handling details:
  12  *  reading the RTC at bootup, etc...
  13  *
  14  *  1994-07-02  Alan Modra
  15  *              fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
  16  *  1998-12-20  Updated NTP code according to technical memorandum Jan '96
  17  *              "A Kernel Model for Precision Timekeeping" by Dave Mills
  18  */
  19 #include <linux/config.h>
  20 #include <linux/module.h>
  21 #include <linux/kernel.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/time.h>
  24 #include <linux/init.h>
  25 #include <linux/smp.h>
  26 #include <linux/timex.h>
  27 #include <linux/errno.h>
  28 #include <linux/profile.h>
  29 #include <linux/sysdev.h>
  30 #include <linux/timer.h>
  31
  32 #include <asm/hardware.h>
  33 #include <asm/io.h>
  34 #include <asm/irq.h>
  35 #include <asm/leds.h>
  36 #include <asm/thread_info.h>
  37 #include <asm/mach/time.h>
  38
  39 u64 jiffies_64 = INITIAL_JIFFIES;
  40
  41 EXPORT_SYMBOL(jiffies_64);
  42
  43 extern unsigned long wall_jiffies;
  44
  45 /* this needs a better home */
  46 spinlock_t rtc_lock = SPIN_LOCK_UNLOCKED;
  47
  48 #ifdef CONFIG_SA1100_RTC_MODULE
  49 EXPORT_SYMBOL(rtc_lock);
  50 #endif
  51
  52 /* change this if you have some constant time drift */
  53 #define USECS_PER_JIFFY (1000000/HZ)
  54
  55 #ifdef CONFIG_SMP
  56 unsigned long profile_pc(struct pt_regs *regs)
  57 {
  58         unsigned long fp, pc = instruction_pointer(regs);
  59
  60         if (in_lock_functions(pc)) {
  61                 fp = thread_saved_fp(current);
  62                 pc = pc_pointer(((unsigned long *)fp)[-1]);
  63         }
  64
  65         return pc;
  66 }
  67 EXPORT_SYMBOL(profile_pc);
  68 #endif
  69
  70 /*
  71  * hook for setting the RTC's idea of the current time.
  72  */
  73 int (*set_rtc)(void);
  74
  75 static unsigned long dummy_gettimeoffset(void)
  76 {
  77         return 0;
  78 }
  79
  80 /*
  81  * hook for getting the time offset.  Note that it is
  82  * always called with interrupts disabled.
  83  */
  84 unsigned long (*gettimeoffset)(void) = dummy_gettimeoffset;
  85
  86 /*
  87  * Scheduler clock - returns current time in nanosec units.
  88  * This is the default implementation.  Sub-architecture
  89  * implementations can override this.
  90  */
  91 unsigned long long __attribute__((weak)) sched_clock(void)
  92 {
  93 #if 1   // mask by Victor Yu. 06-06-2005
  94         return (unsigned long long)jiffies * (1000000000 / HZ);
  95 #else   // add by Victor Yu. 06-06-2005
  96         unsigned long long      ret;
  97
  98         ret = (unsigned long long)((unsigned long long)1000000000 / (unsigned long long)HZ);
  99         ret *= (unsigned long long)jiffies;
 100         return ret;
 101 #endif
 102 }
 103
 104 static unsigned long next_rtc_update;
 105
 106 /*
 107  * If we have an externally synchronized linux clock, then update
 108  * CMOS clock accordingly every ~11 minutes.  set_rtc() has to be
 109  * called as close as possible to 500 ms before the new second
 110  * starts.
 111  */
 112 static inline void do_set_rtc(void)
 113 {
 114         if (time_status & STA_UNSYNC || set_rtc == NULL)
 115                 return;
 116
 117         if (next_rtc_update &&
 118             time_before((unsigned long)xtime.tv_sec, next_rtc_update))
 119                 return;
 120
 121         if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
 122             xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
 123                 return;
 124
 125         if (set_rtc())
 126                 /*
 127                  * rtc update failed.  Try again in 60s
 128                  */
 129                 next_rtc_update = xtime.tv_sec + 60;
 130         else
 131                 next_rtc_update = xtime.tv_sec + 660;
 132 }
 133
 134 #ifdef CONFIG_LEDS
 135
 136 static void dummy_leds_event(led_event_t evt)
 137 {
 138 }
 139
 140 void (*leds_event)(led_event_t) = dummy_leds_event;
 141
 142 struct leds_evt_name {
 143         const char      name[8];
 144         int             on;
 145         int             off;
 146 };
 147
 148 static const struct leds_evt_name evt_names[] = {
 149         { "amber", led_amber_on, led_amber_off },
 150         { "blue",  led_blue_on,  led_blue_off  },
 151         { "green", led_green_on, led_green_off },
 152         { "red",   led_red_on,   led_red_off   },
 153 };
 154
 155 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
 156 {
 157         int ret = -EINVAL, len = strcspn(buf, " ");
 158
 159         if (len > 0 && buf[len] == '\0')
 160                 len--;
 161
 162         if (strncmp(buf, "claim", len) == 0) {
 163                 leds_event(led_claim);
 164                 ret = size;
 165         } else if (strncmp(buf, "release", len) == 0) {
 166                 leds_event(led_release);
 167                 ret = size;
 168         } else {
 169                 int i;
 170
 171                 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
 172                         if (strlen(evt_names[i].name) != len ||
 173                             strncmp(buf, evt_names[i].name, len) != 0)
 174                                 continue;
 175                         if (strncmp(buf+len, " on", 3) == 0) {
 176                                 leds_event(evt_names[i].on);
 177                                 ret = size;
 178                         } else if (strncmp(buf+len, " off", 4) == 0) {
 179                                 leds_event(evt_names[i].off);
 180                                 ret = size;
 181                         }
 182                         break;
 183                 }
 184         }
 185         return ret;
 186 }
 187
 188 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
 189
 190 static int leds_suspend(struct sys_device *dev, u32 state)
 191 {
 192         leds_event(led_stop);
 193         return 0;
 194 }
 195
 196 static int leds_resume(struct sys_device *dev)
 197 {
 198         leds_event(led_start);
 199         return 0;
 200 }
 201
 202 static int leds_shutdown(struct sys_device *dev)
 203 {
 204         leds_event(led_halted);
 205         return 0;
 206 }
 207
 208 static struct sysdev_class leds_sysclass = {
 209         set_kset_name("leds"),
 210         .shutdown       = leds_shutdown,
 211         .suspend        = leds_suspend,
 212         .resume         = leds_resume,
 213 };
 214
 215 static struct sys_device leds_device = {
 216         .id             = 0,
 217         .cls            = &leds_sysclass,
 218 };
 219
 220 static int __init leds_init(void)
 221 {
 222         int ret;
 223         ret = sysdev_class_register(&leds_sysclass);
 224         if (ret == 0)
 225                 ret = sysdev_register(&leds_device);
 226         if (ret == 0)
 227                 ret = sysdev_create_file(&leds_device, &attr_event);
 228         return ret;
 229 }
 230
 231 device_initcall(leds_init);
 232
 233 EXPORT_SYMBOL(leds_event);
 234 #endif
 235
 236 #ifdef CONFIG_LEDS_TIMER
 237 static inline void do_leds(void)
 238 {
 239         static unsigned int count = 50;
 240
 241         if (--count == 0) {
 242                 count = 50;
 243                 leds_event(led_timer);
 244         }
 245 }
 246 #else
 247 #define do_leds()
 248 #endif
 249
 250 void do_gettimeofday(struct timeval *tv)
 251 {
 252         unsigned long flags;
 253         unsigned long seq;
 254         unsigned long usec, sec, lost;
 255
 256         do {
 257                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 258                 usec = gettimeoffset();
 259
 260                 lost = jiffies - wall_jiffies;
 261                 if (lost)
 262                         usec += lost * USECS_PER_JIFFY;
 263
 264                 sec = xtime.tv_sec;
 265                 usec += xtime.tv_nsec / 1000;
 266         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 267
 268         /* usec may have gone up a lot: be safe */
 269         while (usec >= 1000000) {
 270                 usec -= 1000000;
 271                 sec++;
 272         }
 273
 274         tv->tv_sec = sec;
 275         tv->tv_usec = usec;
 276 }
 277
 278 EXPORT_SYMBOL(do_gettimeofday);
 279
 280 int do_settimeofday(struct timespec *tv)
 281 {
 282         time_t wtm_sec, sec = tv->tv_sec;
 283         long wtm_nsec, nsec = tv->tv_nsec;
 284
 285         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 286                 return -EINVAL;
 287
 288         write_seqlock_irq(&xtime_lock);
 289         /*
 290          * This is revolting. We need to set "xtime" correctly. However, the
 291          * value in this location is the value at the most recent update of
 292          * wall time.  Discover what correction gettimeofday() would have
 293          * done, and then undo it!
 294          */
 295         nsec -= gettimeoffset() * NSEC_PER_USEC;
 296         nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
 297
 298         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 299         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 300
 301         set_normalized_timespec(&xtime, sec, nsec);
 302         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 303
 304         time_adjust = 0;                /* stop active adjtime() */
 305         time_status |= STA_UNSYNC;
 306         time_maxerror = NTP_PHASE_LIMIT;
 307         time_esterror = NTP_PHASE_LIMIT;
 308         write_sequnlock_irq(&xtime_lock);
 309         clock_was_set();
 310         return 0;
 311 }
 312
 313 EXPORT_SYMBOL(do_settimeofday);
 314
 315 /**
 316  * save_time_delta - Save the offset between system time and RTC time
 317  * @delta: pointer to timespec to store delta
 318  * @rtc: pointer to timespec for current RTC time
 319  *
 320  * Return a delta between the system time and the RTC time, such
 321  * that system time can be restored later with restore_time_delta()
 322  */
 323 void save_time_delta(struct timespec *delta, struct timespec *rtc)
 324 {
 325         set_normalized_timespec(delta,
 326                                 xtime.tv_sec - rtc->tv_sec,
 327                                 xtime.tv_nsec - rtc->tv_nsec);
 328 }
 329 EXPORT_SYMBOL(save_time_delta);
 330
 331 /**
 332  * restore_time_delta - Restore the current system time
 333  * @delta: delta returned by save_time_delta()
 334  * @rtc: pointer to timespec for current RTC time
 335  */
 336 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
 337 {
 338         struct timespec ts;
 339
 340         set_normalized_timespec(&ts,
 341                                 delta->tv_sec + rtc->tv_sec,
 342                                 delta->tv_nsec + rtc->tv_nsec);
 343
 344         do_settimeofday(&ts);
 345 }
 346 EXPORT_SYMBOL(restore_time_delta);
 347
 348 void timer_tick(struct pt_regs *regs)
 349 {
 350         profile_tick(CPU_PROFILING, regs);
 351         do_leds();
 352         do_set_rtc();
 353         do_timer(regs);
 354 }
 355
 356 void (*init_arch_time)(void);
 357
 358 void __init time_init(void)
 359 {
 360         init_arch_time();
 361 }
 362