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/smp.h>
  25 #include <linux/timex.h>
  26 #include <linux/errno.h>
  27 #include <linux/profile.h>
  28 #include <linux/sysdev.h>
  29 #include <linux/timer.h>
  30 #include <linux/irq.h>
  31
  32 #include <linux/mc146818rtc.h>
  33
  34 #include <asm/leds.h>
  35 #include <asm/thread_info.h>
  36 #include <asm/stacktrace.h>
  37 #include <asm/mach/time.h>
  38
  39 /*
  40  * Our system timer.
  41  */
  42 struct sys_timer *system_timer;
  43
  44 #if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE)
  45 /* this needs a better home */
  46 DEFINE_SPINLOCK(rtc_lock);
  47
  48 #ifdef CONFIG_RTC_DRV_CMOS_MODULE
  49 EXPORT_SYMBOL(rtc_lock);
  50 #endif
  51 #endif  /* pc-style 'CMOS' RTC support */
  52
  53 /* change this if you have some constant time drift */
  54 #define USECS_PER_JIFFY (1000000/HZ)
  55
  56 #ifdef CONFIG_SMP
  57 unsigned long profile_pc(struct pt_regs *regs)
  58 {
  59         struct stackframe frame;
  60
  61         if (!in_lock_functions(regs->ARM_pc))
  62                 return regs->ARM_pc;
  63
  64         frame.fp = regs->ARM_fp;
  65         frame.sp = regs->ARM_sp;
  66         frame.lr = regs->ARM_lr;
  67         frame.pc = regs->ARM_pc;
  68         do {
  69                 int ret = unwind_frame(&frame);
  70                 if (ret < 0)
  71                         return 0;
  72         } while (in_lock_functions(frame.pc));
  73
  74         return frame.pc;
  75 }
  76 EXPORT_SYMBOL(profile_pc);
  77 #endif
  78
  79 /*
  80  * hook for setting the RTC's idea of the current time.
  81  */
  82 int (*set_rtc)(void);
  83
  84 #ifndef CONFIG_GENERIC_TIME
  85 static unsigned long dummy_gettimeoffset(void)
  86 {
  87         return 0;
  88 }
  89 #endif
  90
  91 static unsigned long next_rtc_update;
  92
  93 /*
  94  * If we have an externally synchronized linux clock, then update
  95  * CMOS clock accordingly every ~11 minutes.  set_rtc() has to be
  96  * called as close as possible to 500 ms before the new second
  97  * starts.
  98  */
  99 static inline void do_set_rtc(void)
 100 {
 101         if (!ntp_synced() || set_rtc == NULL)
 102                 return;
 103
 104         if (next_rtc_update &&
 105             time_before((unsigned long)xtime.tv_sec, next_rtc_update))
 106                 return;
 107
 108         if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
 109             xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
 110                 return;
 111
 112         if (set_rtc())
 113                 /*
 114                  * rtc update failed.  Try again in 60s
 115                  */
 116                 next_rtc_update = xtime.tv_sec + 60;
 117         else
 118                 next_rtc_update = xtime.tv_sec + 660;
 119 }
 120
 121 #ifdef CONFIG_LEDS
 122
 123 static void dummy_leds_event(led_event_t evt)
 124 {
 125 }
 126
 127 void (*leds_event)(led_event_t) = dummy_leds_event;
 128
 129 struct leds_evt_name {
 130         const char      name[8];
 131         int             on;
 132         int             off;
 133 };
 134
 135 static const struct leds_evt_name evt_names[] = {
 136         { "amber", led_amber_on, led_amber_off },
 137         { "blue",  led_blue_on,  led_blue_off  },
 138         { "green", led_green_on, led_green_off },
 139         { "red",   led_red_on,   led_red_off   },
 140 };
 141
 142 static ssize_t leds_store(struct sys_device *dev,
 143                         struct sysdev_attribute *attr,
 144                         const char *buf, size_t size)
 145 {
 146         int ret = -EINVAL, len = strcspn(buf, " ");
 147
 148         if (len > 0 && buf[len] == '\0')
 149                 len--;
 150
 151         if (strncmp(buf, "claim", len) == 0) {
 152                 leds_event(led_claim);
 153                 ret = size;
 154         } else if (strncmp(buf, "release", len) == 0) {
 155                 leds_event(led_release);
 156                 ret = size;
 157         } else {
 158                 int i;
 159
 160                 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
 161                         if (strlen(evt_names[i].name) != len ||
 162                             strncmp(buf, evt_names[i].name, len) != 0)
 163                                 continue;
 164                         if (strncmp(buf+len, " on", 3) == 0) {
 165                                 leds_event(evt_names[i].on);
 166                                 ret = size;
 167                         } else if (strncmp(buf+len, " off", 4) == 0) {
 168                                 leds_event(evt_names[i].off);
 169                                 ret = size;
 170                         }
 171                         break;
 172                 }
 173         }
 174         return ret;
 175 }
 176
 177 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
 178
 179 static int leds_suspend(struct sys_device *dev, pm_message_t state)
 180 {
 181         leds_event(led_stop);
 182         return 0;
 183 }
 184
 185 static int leds_resume(struct sys_device *dev)
 186 {
 187         leds_event(led_start);
 188         return 0;
 189 }
 190
 191 static int leds_shutdown(struct sys_device *dev)
 192 {
 193         leds_event(led_halted);
 194         return 0;
 195 }
 196
 197 static struct sysdev_class leds_sysclass = {
 198         .name           = "leds",
 199         .shutdown       = leds_shutdown,
 200         .suspend        = leds_suspend,
 201         .resume         = leds_resume,
 202 };
 203
 204 static struct sys_device leds_device = {
 205         .id             = 0,
 206         .cls            = &leds_sysclass,
 207 };
 208
 209 static int __init leds_init(void)
 210 {
 211         int ret;
 212         ret = sysdev_class_register(&leds_sysclass);
 213         if (ret == 0)
 214                 ret = sysdev_register(&leds_device);
 215         if (ret == 0)
 216                 ret = sysdev_create_file(&leds_device, &attr_event);
 217         return ret;
 218 }
 219
 220 device_initcall(leds_init);
 221
 222 EXPORT_SYMBOL(leds_event);
 223 #endif
 224
 225 #ifdef CONFIG_LEDS_TIMER
 226 static inline void do_leds(void)
 227 {
 228         static unsigned int count = HZ/2;
 229
 230         if (--count == 0) {
 231                 count = HZ/2;
 232                 leds_event(led_timer);
 233         }
 234 }
 235 #else
 236 #define do_leds()
 237 #endif
 238
 239 #ifndef CONFIG_GENERIC_TIME
 240 void do_gettimeofday(struct timeval *tv)
 241 {
 242         unsigned long flags;
 243         unsigned long seq;
 244         unsigned long usec, sec;
 245
 246         do {
 247                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 248                 usec = system_timer->offset();
 249                 sec = xtime.tv_sec;
 250                 usec += xtime.tv_nsec / 1000;
 251         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 252
 253         /* usec may have gone up a lot: be safe */
 254         while (usec >= 1000000) {
 255                 usec -= 1000000;
 256                 sec++;
 257         }
 258
 259         tv->tv_sec = sec;
 260         tv->tv_usec = usec;
 261 }
 262
 263 EXPORT_SYMBOL(do_gettimeofday);
 264
 265 int do_settimeofday(struct timespec *tv)
 266 {
 267         time_t wtm_sec, sec = tv->tv_sec;
 268         long wtm_nsec, nsec = tv->tv_nsec;
 269
 270         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 271                 return -EINVAL;
 272
 273         write_seqlock_irq(&xtime_lock);
 274         /*
 275          * This is revolting. We need to set "xtime" correctly. However, the
 276          * value in this location is the value at the most recent update of
 277          * wall time.  Discover what correction gettimeofday() would have
 278          * done, and then undo it!
 279          */
 280         nsec -= system_timer->offset() * NSEC_PER_USEC;
 281
 282         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 283         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 284
 285         set_normalized_timespec(&xtime, sec, nsec);
 286         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 287
 288         ntp_clear();
 289         write_sequnlock_irq(&xtime_lock);
 290         clock_was_set();
 291         return 0;
 292 }
 293
 294 EXPORT_SYMBOL(do_settimeofday);
 295 #endif /* !CONFIG_GENERIC_TIME */
 296
 297 /**
 298  * save_time_delta - Save the offset between system time and RTC time
 299  * @delta: pointer to timespec to store delta
 300  * @rtc: pointer to timespec for current RTC time
 301  *
 302  * Return a delta between the system time and the RTC time, such
 303  * that system time can be restored later with restore_time_delta()
 304  */
 305 void save_time_delta(struct timespec *delta, struct timespec *rtc)
 306 {
 307         set_normalized_timespec(delta,
 308                                 xtime.tv_sec - rtc->tv_sec,
 309                                 xtime.tv_nsec - rtc->tv_nsec);
 310 }
 311 EXPORT_SYMBOL(save_time_delta);
 312
 313 /**
 314  * restore_time_delta - Restore the current system time
 315  * @delta: delta returned by save_time_delta()
 316  * @rtc: pointer to timespec for current RTC time
 317  */
 318 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
 319 {
 320         struct timespec ts;
 321
 322         set_normalized_timespec(&ts,
 323                                 delta->tv_sec + rtc->tv_sec,
 324                                 delta->tv_nsec + rtc->tv_nsec);
 325
 326         do_settimeofday(&ts);
 327 }
 328 EXPORT_SYMBOL(restore_time_delta);
 329
 330 #ifndef CONFIG_GENERIC_CLOCKEVENTS
 331 /*
 332  * Kernel system timer support.
 333  */
 334 void timer_tick(void)
 335 {
 336         profile_tick(CPU_PROFILING);
 337         do_leds();
 338         do_set_rtc();
 339         write_seqlock(&xtime_lock);
 340         do_timer(1);
 341         write_sequnlock(&xtime_lock);
 342 #ifndef CONFIG_SMP
 343         update_process_times(user_mode(get_irq_regs()));
 344 #endif
 345 }
 346 #endif
 347
 348 #if defined(CONFIG_PM) && !defined(CONFIG_GENERIC_CLOCKEVENTS)
 349 static int timer_suspend(struct sys_device *dev, pm_message_t state)
 350 {
 351         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 352
 353         if (timer->suspend != NULL)
 354                 timer->suspend();
 355
 356         return 0;
 357 }
 358
 359 static int timer_resume(struct sys_device *dev)
 360 {
 361         struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
 362
 363         if (timer->resume != NULL)
 364                 timer->resume();
 365
 366         return 0;
 367 }
 368 #else
 369 #define timer_suspend NULL
 370 #define timer_resume NULL
 371 #endif
 372
 373 static struct sysdev_class timer_sysclass = {
 374         .name           = "timer",
 375         .suspend        = timer_suspend,
 376         .resume         = timer_resume,
 377 };
 378
 379 static int __init timer_init_sysfs(void)
 380 {
 381         int ret = sysdev_class_register(&timer_sysclass);
 382         if (ret == 0) {
 383                 system_timer->dev.cls = &timer_sysclass;
 384                 ret = sysdev_register(&system_timer->dev);
 385         }
 386
 387         return ret;
 388 }
 389
 390 device_initcall(timer_init_sysfs);
 391
 392 void __init time_init(void)
 393 {
 394 #ifndef CONFIG_GENERIC_TIME
 395         if (system_timer->offset == NULL)
 396                 system_timer->offset = dummy_gettimeoffset;
 397 #endif
 398         system_timer->init();
 399 }
 400