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 /*
  44  * Our system timer.
  45  */
  46 struct sys_timer *system_timer;
  47
  48 extern unsigned long wall_jiffies;
  49
  50 /* this needs a better home */
  51 DEFINE_SPINLOCK(rtc_lock);
  52
  53 #ifdef CONFIG_SA1100_RTC_MODULE
  54 EXPORT_SYMBOL(rtc_lock);
  55 #endif
  56
  57 /* change this if you have some constant time drift */
  58 #define USECS_PER_JIFFY (1000000/HZ)
  59
  60 #ifdef CONFIG_SMP
  61 unsigned long profile_pc(struct pt_regs *regs)
  62 {
  63         unsigned long fp, pc = instruction_pointer(regs);
  64
  65         if (in_lock_functions(pc)) {
  66                 fp = regs->ARM_fp;
  67                 pc = pc_pointer(((unsigned long *)fp)[-1]);
  68         }
  69
  70         return pc;
  71 }
  72 EXPORT_SYMBOL(profile_pc);
  73 #endif
  74
  75 /*
  76  * hook for setting the RTC's idea of the current time.
  77  */
  78 int (*set_rtc)(void);
  79
  80 static unsigned long dummy_gettimeoffset(void)
  81 {
  82         return 0;
  83 }
  84
  85 /*
  86  * Scheduler clock - returns current time in nanosec units.
  87  * This is the default implementation.  Sub-architecture
  88  * implementations can override this.
  89  */
  90 unsigned long long __attribute__((weak)) sched_clock(void)
  91 {
  92         return (unsigned long long)jiffies * (1000000000 / HZ);
  93 }
  94
  95 static unsigned long next_rtc_update;
  96
  97 /*
  98  * If we have an externally synchronized linux clock, then update
  99  * CMOS clock accordingly every ~11 minutes.  set_rtc() has to be
 100  * called as close as possible to 500 ms before the new second
 101  * starts.
 102  */
 103 static inline void do_set_rtc(void)
 104 {
 105         if (time_status & STA_UNSYNC || set_rtc == NULL)
 106                 return;
 107
 108         if (next_rtc_update &&
 109             time_before((unsigned long)xtime.tv_sec, next_rtc_update))
 110                 return;
 111
 112         if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
 113             xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
 114                 return;
 115
 116         if (set_rtc())
 117                 /*
 118                  * rtc update failed.  Try again in 60s
 119                  */
 120                 next_rtc_update = xtime.tv_sec + 60;
 121         else
 122                 next_rtc_update = xtime.tv_sec + 660;
 123 }
 124
 125 #ifdef CONFIG_LEDS
 126
 127 static void dummy_leds_event(led_event_t evt)
 128 {
 129 }
 130
 131 void (*leds_event)(led_event_t) = dummy_leds_event;
 132
 133 struct leds_evt_name {
 134         const char      name[8];
 135         int             on;
 136         int             off;
 137 };
 138
 139 static const struct leds_evt_name evt_names[] = {
 140         { "amber", led_amber_on, led_amber_off },
 141         { "blue",  led_blue_on,  led_blue_off  },
 142         { "green", led_green_on, led_green_off },
 143         { "red",   led_red_on,   led_red_off   },
 144 };
 145
 146 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
 147 {
 148         int ret = -EINVAL, len = strcspn(buf, " ");
 149
 150         if (len > 0 && buf[len] == '\0')
 151                 len--;
 152
 153         if (strncmp(buf, "claim", len) == 0) {
 154                 leds_event(led_claim);
 155                 ret = size;
 156         } else if (strncmp(buf, "release", len) == 0) {
 157                 leds_event(led_release);
 158                 ret = size;
 159         } else {
 160                 int i;
 161
 162                 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
 163                         if (strlen(evt_names[i].name) != len ||
 164                             strncmp(buf, evt_names[i].name, len) != 0)
 165                                 continue;
 166                         if (strncmp(buf+len, " on", 3) == 0) {
 167                                 leds_event(evt_names[i].on);
 168                                 ret = size;
 169                         } else if (strncmp(buf+len, " off", 4) == 0) {
 170                                 leds_event(evt_names[i].off);
 171                                 ret = size;
 172                         }
 173                         break;
 174                 }
 175         }
 176         return ret;
 177 }
 178
 179 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
 180
 181 static int leds_suspend(struct sys_device *dev, pm_message_t state)
 182 {
 183         leds_event(led_stop);
 184         return 0;
 185 }
 186
 187 static int leds_resume(struct sys_device *dev)
 188 {
 189         leds_event(led_start);
 190         return 0;
 191 }
 192
 193 static int leds_shutdown(struct sys_device *dev)
 194 {
 195         leds_event(led_halted);
 196         return 0;
 197 }
 198
 199 static struct sysdev_class leds_sysclass = {
 200         set_kset_name("leds"),
 201         .shutdown       = leds_shutdown,
 202         .suspend        = leds_suspend,
 203         .resume         = leds_resume,
 204 };
 205
 206 static struct sys_device leds_device = {
 207         .id             = 0,
 208         .cls            = &leds_sysclass,
 209 };
 210
 211 static int __init leds_init(void)
 212 {
 213         int ret;
 214         ret = sysdev_class_register(&leds_sysclass);
 215         if (ret == 0)
 216                 ret = sysdev_register(&leds_device);
 217         if (ret == 0)
 218                 ret = sysdev_create_file(&leds_device, &attr_event);
 219         return ret;
 220 }
 221
 222 device_initcall(leds_init);
 223
 224 EXPORT_SYMBOL(leds_event);
 225 #endif
 226
 227 #ifdef CONFIG_LEDS_TIMER
 228 static inline void do_leds(void)
 229 {
 230         static unsigned int count = 50;
 231
 232         if (--count == 0) {
 233                 count = 50;
 234                 leds_event(led_timer);
 235         }
 236 }
 237 #else
 238 #define do_leds()
 239 #endif
 240
 241 void do_gettimeofday(struct timeval *tv)
 242 {
 243         unsigned long flags;
 244         unsigned long seq;
 245         unsigned long usec, sec, lost;
 246
 247         do {
 248                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 249                 usec = system_timer->offset();
 250
 251                 lost = jiffies - wall_jiffies;
 252                 if (lost)
 253                         usec += lost * USECS_PER_JIFFY;
 254
 255                 sec = xtime.tv_sec;
 256                 usec += xtime.tv_nsec / 1000;
 257         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 258
 259         /* usec may have gone up a lot: be safe */
 260         while (usec >= 1000000) {
 261                 usec -= 1000000;
 262                 sec++;
 263         }
 264
 265         tv->tv_sec = sec;
 266         tv->tv_usec = usec;
 267 }
 268
 269 EXPORT_SYMBOL(do_gettimeofday);
 270
 271 int do_settimeofday(struct timespec *tv)
 272 {
 273         time_t wtm_sec, sec = tv->tv_sec;
 274         long wtm_nsec, nsec = tv->tv_nsec;
 275
 276         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 277                 return -EINVAL;
 278
 279         write_seqlock_irq(&xtime_lock);
 280         /*
 281          * This is revolting. We need to set "xtime" correctly. However, the
 282          * value in this location is the value at the most recent update of
 283          * wall time.  Discover what correction gettimeofday() would have
 284          * done, and then undo it!
 285          */
 286         nsec -= system_timer->offset() * NSEC_PER_USEC;
 287         nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
 288
 289         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 290         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 291
 292         set_normalized_timespec(&xtime, sec, nsec);
 293         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 294
 295         time_adjust = 0;                /* stop active adjtime() */
 296         time_status |= STA_UNSYNC;
 297         time_maxerror = NTP_PHASE_LIMIT;
 298         time_esterror = NTP_PHASE_LIMIT;
 299         write_sequnlock_irq(&xtime_lock);
 300         clock_was_set();
 301         return 0;
 302 }
 303
 304 EXPORT_SYMBOL(do_settimeofday);
 305
 306 /**
 307  * save_time_delta - Save the offset between system time and RTC time
 308  * @delta: pointer to timespec to store delta
 309  * @rtc: pointer to timespec for current RTC time
 310  *
 311  * Return a delta between the system time and the RTC time, such
 312  * that system time can be restored later with restore_time_delta()
 313  */
 314 void save_time_delta(struct timespec *delta, struct timespec *rtc)
 315 {
 316         set_normalized_timespec(delta,
 317                                 xtime.tv_sec - rtc->tv_sec,
 318                                 xtime.tv_nsec - rtc->tv_nsec);
 319 }
 320 EXPORT_SYMBOL(save_time_delta);
 321
 322 /**
 323  * restore_time_delta - Restore the current system time
 324  * @delta: delta returned by save_time_delta()
 325  * @rtc: pointer to timespec for current RTC time
 326  */
 327 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
 328 {
 329         struct timespec ts;
 330
 331         set_normalized_timespec(&ts,
 332                                 delta->tv_sec + rtc->tv_sec,
 333                                 delta->tv_nsec + rtc->tv_nsec);
 334
 335         do_settimeofday(&ts);
 336 }
 337 EXPORT_SYMBOL(restore_time_delta);
 338
 339 /*
 340  * Kernel system timer support.
 341  */
 342 void timer_tick(struct pt_regs *regs)
 343 {
 344         profile_tick(CPU_PROFILING, regs);
 345         do_leds();
 346         do_set_rtc();
 347         do_timer(regs);
 348 #ifndef CONFIG_SMP
 349         update_process_times(user_mode(regs));
 350 #endif
 351 }
 352
 353 #ifdef CONFIG_PM
 354 static int timer_suspend(struct sys_device *dev, pm_message_t state)
 355 {
 356         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 357
 358         if (timer->suspend != NULL)
 359                 timer->suspend();
 360
 361         return 0;
 362 }
 363
 364 static int timer_resume(struct sys_device *dev)
 365 {
 366         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 367
 368         if (timer->resume != NULL)
 369                 timer->resume();
 370
 371         return 0;
 372 }
 373 #else
 374 #define timer_suspend NULL
 375 #define timer_resume NULL
 376 #endif
 377
 378 static struct sysdev_class timer_sysclass = {
 379         set_kset_name("timer"),
 380         .suspend        = timer_suspend,
 381         .resume         = timer_resume,
 382 };
 383
 384 static int __init timer_init_sysfs(void)
 385 {
 386         int ret = sysdev_class_register(&timer_sysclass);
 387         if (ret == 0) {
 388                 system_timer->dev.cls = &timer_sysclass;
 389                 ret = sysdev_register(&system_timer->dev);
 390         }
 391         return ret;
 392 }
 393
 394 device_initcall(timer_init_sysfs);
 395
 396 void __init time_init(void)
 397 {
 398         if (system_timer->offset == NULL)
 399                 system_timer->offset = dummy_gettimeoffset;
 400         system_timer->init();
 401 }
 402