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/module.h>
  20 #include <linux/kernel.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/time.h>
  23 #include <linux/init.h>
  24 #include <linux/sched.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 #include <linux/irq.h>
  32
  33 #include <linux/mc146818rtc.h>
  34
  35 #include <asm/leds.h>
  36 #include <asm/thread_info.h>
  37 #include <asm/stacktrace.h>
  38 #include <asm/mach/time.h>
  39
  40 /*
  41  * Our system timer.
  42  */
  43 struct sys_timer *system_timer;
  44
  45 #if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE)
  46 /* this needs a better home */
  47 DEFINE_SPINLOCK(rtc_lock);
  48
  49 #ifdef CONFIG_RTC_DRV_CMOS_MODULE
  50 EXPORT_SYMBOL(rtc_lock);
  51 #endif
  52 #endif  /* pc-style 'CMOS' RTC support */
  53
  54 /* change this if you have some constant time drift */
  55 #define USECS_PER_JIFFY (1000000/HZ)
  56
  57 #ifdef CONFIG_SMP
  58 unsigned long profile_pc(struct pt_regs *regs)
  59 {
  60         struct stackframe frame;
  61
  62         if (!in_lock_functions(regs->ARM_pc))
  63                 return regs->ARM_pc;
  64
  65         frame.fp = regs->ARM_fp;
  66         frame.sp = regs->ARM_sp;
  67         frame.lr = regs->ARM_lr;
  68         frame.pc = regs->ARM_pc;
  69         do {
  70                 int ret = unwind_frame(&frame);
  71                 if (ret < 0)
  72                         return 0;
  73         } while (in_lock_functions(frame.pc));
  74
  75         return frame.pc;
  76 }
  77 EXPORT_SYMBOL(profile_pc);
  78 #endif
  79
  80 /*
  81  * hook for setting the RTC's idea of the current time.
  82  */
  83 int (*set_rtc)(void);
  84
  85 #ifndef CONFIG_GENERIC_TIME
  86 static unsigned long dummy_gettimeoffset(void)
  87 {
  88         return 0;
  89 }
  90 #endif
  91
  92 static unsigned long next_rtc_update;
  93
  94 /*
  95  * If we have an externally synchronized linux clock, then update
  96  * CMOS clock accordingly every ~11 minutes.  set_rtc() has to be
  97  * called as close as possible to 500 ms before the new second
  98  * starts.
  99  */
 100 static inline void do_set_rtc(void)
 101 {
 102         if (!ntp_synced() || set_rtc == NULL)
 103                 return;
 104
 105         if (next_rtc_update &&
 106             time_before((unsigned long)xtime.tv_sec, next_rtc_update))
 107                 return;
 108
 109         if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
 110             xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
 111                 return;
 112
 113         if (set_rtc())
 114                 /*
 115                  * rtc update failed.  Try again in 60s
 116                  */
 117                 next_rtc_update = xtime.tv_sec + 60;
 118         else
 119                 next_rtc_update = xtime.tv_sec + 660;
 120 }
 121
 122 #ifdef CONFIG_LEDS
 123
 124 static void dummy_leds_event(led_event_t evt)
 125 {
 126 }
 127
 128 void (*leds_event)(led_event_t) = dummy_leds_event;
 129
 130 struct leds_evt_name {
 131         const char      name[8];
 132         int             on;
 133         int             off;
 134 };
 135
 136 static const struct leds_evt_name evt_names[] = {
 137         { "amber", led_amber_on, led_amber_off },
 138         { "blue",  led_blue_on,  led_blue_off  },
 139         { "green", led_green_on, led_green_off },
 140         { "red",   led_red_on,   led_red_off   },
 141 };
 142
 143 static ssize_t leds_store(struct sys_device *dev,
 144                         struct sysdev_attribute *attr,
 145                         const char *buf, size_t size)
 146 {
 147         int ret = -EINVAL, len = strcspn(buf, " ");
 148
 149         if (len > 0 && buf[len] == '\0')
 150                 len--;
 151
 152         if (strncmp(buf, "claim", len) == 0) {
 153                 leds_event(led_claim);
 154                 ret = size;
 155         } else if (strncmp(buf, "release", len) == 0) {
 156                 leds_event(led_release);
 157                 ret = size;
 158         } else {
 159                 int i;
 160
 161                 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
 162                         if (strlen(evt_names[i].name) != len ||
 163                             strncmp(buf, evt_names[i].name, len) != 0)
 164                                 continue;
 165                         if (strncmp(buf+len, " on", 3) == 0) {
 166                                 leds_event(evt_names[i].on);
 167                                 ret = size;
 168                         } else if (strncmp(buf+len, " off", 4) == 0) {
 169                                 leds_event(evt_names[i].off);
 170                                 ret = size;
 171                         }
 172                         break;
 173                 }
 174         }
 175         return ret;
 176 }
 177
 178 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
 179
 180 static int leds_suspend(struct sys_device *dev, pm_message_t state)
 181 {
 182         leds_event(led_stop);
 183         return 0;
 184 }
 185
 186 static int leds_resume(struct sys_device *dev)
 187 {
 188         leds_event(led_start);
 189         return 0;
 190 }
 191
 192 static int leds_shutdown(struct sys_device *dev)
 193 {
 194         leds_event(led_halted);
 195         return 0;
 196 }
 197
 198 static struct sysdev_class leds_sysclass = {
 199         .name           = "leds",
 200         .shutdown       = leds_shutdown,
 201         .suspend        = leds_suspend,
 202         .resume         = leds_resume,
 203 };
 204
 205 static struct sys_device leds_device = {
 206         .id             = 0,
 207         .cls            = &leds_sysclass,
 208 };
 209
 210 static int __init leds_init(void)
 211 {
 212         int ret;
 213         ret = sysdev_class_register(&leds_sysclass);
 214         if (ret == 0)
 215                 ret = sysdev_register(&leds_device);
 216         if (ret == 0)
 217                 ret = sysdev_create_file(&leds_device, &attr_event);
 218         return ret;
 219 }
 220
 221 device_initcall(leds_init);
 222
 223 EXPORT_SYMBOL(leds_event);
 224 #endif
 225
 226 #ifdef CONFIG_LEDS_TIMER
 227 static inline void do_leds(void)
 228 {
 229         static unsigned int count = HZ/2;
 230
 231         if (--count == 0) {
 232                 count = HZ/2;
 233                 leds_event(led_timer);
 234         }
 235 }
 236 #else
 237 #define do_leds()
 238 #endif
 239
 240 #ifndef CONFIG_GENERIC_TIME
 241 void do_gettimeofday(struct timeval *tv)
 242 {
 243         unsigned long flags;
 244         unsigned long seq;
 245         unsigned long usec, sec;
 246
 247         do {
 248                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 249                 usec = system_timer->offset();
 250                 sec = xtime.tv_sec;
 251                 usec += xtime.tv_nsec / 1000;
 252         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 253
 254         /* usec may have gone up a lot: be safe */
 255         while (usec >= 1000000) {
 256                 usec -= 1000000;
 257                 sec++;
 258         }
 259
 260         tv->tv_sec = sec;
 261         tv->tv_usec = usec;
 262 }
 263
 264 EXPORT_SYMBOL(do_gettimeofday);
 265
 266 int do_settimeofday(struct timespec *tv)
 267 {
 268         time_t wtm_sec, sec = tv->tv_sec;
 269         long wtm_nsec, nsec = tv->tv_nsec;
 270
 271         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 272                 return -EINVAL;
 273
 274         write_seqlock_irq(&xtime_lock);
 275         /*
 276          * This is revolting. We need to set "xtime" correctly. However, the
 277          * value in this location is the value at the most recent update of
 278          * wall time.  Discover what correction gettimeofday() would have
 279          * done, and then undo it!
 280          */
 281         nsec -= system_timer->offset() * NSEC_PER_USEC;
 282
 283         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 284         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 285
 286         set_normalized_timespec(&xtime, sec, nsec);
 287         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 288
 289         ntp_clear();
 290         write_sequnlock_irq(&xtime_lock);
 291         clock_was_set();
 292         return 0;
 293 }
 294
 295 EXPORT_SYMBOL(do_settimeofday);
 296 #endif /* !CONFIG_GENERIC_TIME */
 297
 298 /**
 299  * save_time_delta - Save the offset between system time and RTC time
 300  * @delta: pointer to timespec to store delta
 301  * @rtc: pointer to timespec for current RTC time
 302  *
 303  * Return a delta between the system time and the RTC time, such
 304  * that system time can be restored later with restore_time_delta()
 305  */
 306 void save_time_delta(struct timespec *delta, struct timespec *rtc)
 307 {
 308         set_normalized_timespec(delta,
 309                                 xtime.tv_sec - rtc->tv_sec,
 310                                 xtime.tv_nsec - rtc->tv_nsec);
 311 }
 312 EXPORT_SYMBOL(save_time_delta);
 313
 314 /**
 315  * restore_time_delta - Restore the current system time
 316  * @delta: delta returned by save_time_delta()
 317  * @rtc: pointer to timespec for current RTC time
 318  */
 319 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
 320 {
 321         struct timespec ts;
 322
 323         set_normalized_timespec(&ts,
 324                                 delta->tv_sec + rtc->tv_sec,
 325                                 delta->tv_nsec + rtc->tv_nsec);
 326
 327         do_settimeofday(&ts);
 328 }
 329 EXPORT_SYMBOL(restore_time_delta);
 330
 331 #ifndef CONFIG_GENERIC_CLOCKEVENTS
 332 /*
 333  * Kernel system timer support.
 334  */
 335 void timer_tick(void)
 336 {
 337         profile_tick(CPU_PROFILING);
 338         do_leds();
 339         do_set_rtc();
 340         write_seqlock(&xtime_lock);
 341         do_timer(1);
 342         write_sequnlock(&xtime_lock);
 343 #ifndef CONFIG_SMP
 344         update_process_times(user_mode(get_irq_regs()));
 345 #endif
 346 }
 347 #endif
 348
 349 #if defined(CONFIG_PM) && !defined(CONFIG_GENERIC_CLOCKEVENTS)
 350 static int timer_suspend(struct sys_device *dev, pm_message_t state)
 351 {
 352         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 353
 354         if (timer->suspend != NULL)
 355                 timer->suspend();
 356
 357         return 0;
 358 }
 359
 360 static int timer_resume(struct sys_device *dev)
 361 {
 362         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 363
 364         if (timer->resume != NULL)
 365                 timer->resume();
 366
 367         return 0;
 368 }
 369 #else
 370 #define timer_suspend NULL
 371 #define timer_resume NULL
 372 #endif
 373
 374 static struct sysdev_class timer_sysclass = {
 375         .name           = "timer",
 376         .suspend        = timer_suspend,
 377         .resume         = timer_resume,
 378 };
 379
 380 static int __init timer_init_sysfs(void)
 381 {
 382         int ret = sysdev_class_register(&timer_sysclass);
 383         if (ret == 0) {
 384                 system_timer->dev.cls = &timer_sysclass;
 385                 ret = sysdev_register(&system_timer->dev);
 386         }
 387
 388         return ret;
 389 }
 390
 391 device_initcall(timer_init_sysfs);
 392
 393 void __init time_init(void)
 394 {
 395 #ifndef CONFIG_GENERIC_TIME
 396         if (system_timer->offset == NULL)
 397                 system_timer->offset = dummy_gettimeoffset;
 398 #endif
 399         system_timer->init();
 400 }
 401