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/mach/time.h> 37 38 /* 39 * Our system timer. 40 */ 41 struct sys_timer *system_timer; 42 43 /* this needs a better home */ 44 DEFINE_SPINLOCK(rtc_lock); 45 46 #ifdef CONFIG_SA1100_RTC_MODULE 47 EXPORT_SYMBOL(rtc_lock); 48 #endif 49 50 /* change this if you have some constant time drift */ 51 #define USECS_PER_JIFFY (1000000/HZ) 52 53 #ifdef CONFIG_SMP 54 unsigned long profile_pc(struct pt_regs *regs) 55 { 56 unsigned long fp, pc = instruction_pointer(regs); 57 58 if (in_lock_functions(pc)) { 59 fp = regs->ARM_fp; 60 pc = pc_pointer(((unsigned long *)fp)[-1]); 61 } 62 63 return pc; 64 } 65 EXPORT_SYMBOL(profile_pc); 66 #endif 67 68 /* 69 * hook for setting the RTC's idea of the current time. 70 */ 71 int (*set_rtc)(void); 72 73 #ifndef CONFIG_GENERIC_TIME 74 static unsigned long dummy_gettimeoffset(void) 75 { 76 return 0; 77 } 78 #endif 79 80 /* 81 * Scheduler clock - returns current time in nanosec units. 82 * This is the default implementation. Sub-architecture 83 * implementations can override this. 84 */ 85 unsigned long long __attribute__((weak)) sched_clock(void) 86 { 87 return (unsigned long long)jiffies * (1000000000 / HZ); 88 } 89 90 /* 91 * An implementation of printk_clock() independent from 92 * sched_clock(). This avoids non-bootable kernels when 93 * printk_clock is enabled. 94 */ 95 unsigned long long printk_clock(void) 96 { 97 return (unsigned long long)(jiffies - INITIAL_JIFFIES) * 98 (1000000000 / HZ); 99 } 100 101 static unsigned long next_rtc_update; 102 103 /* 104 * If we have an externally synchronized linux clock, then update 105 * CMOS clock accordingly every ~11 minutes. set_rtc() has to be 106 * called as close as possible to 500 ms before the new second 107 * starts. 108 */ 109 static inline void do_set_rtc(void) 110 { 111 if (!ntp_synced() || set_rtc == NULL) 112 return; 113 114 if (next_rtc_update && 115 time_before((unsigned long)xtime.tv_sec, next_rtc_update)) 116 return; 117 118 if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) && 119 xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1)) 120 return; 121 122 if (set_rtc()) 123 /* 124 * rtc update failed. Try again in 60s 125 */ 126 next_rtc_update = xtime.tv_sec + 60; 127 else 128 next_rtc_update = xtime.tv_sec + 660; 129 } 130 131 #ifdef CONFIG_LEDS 132 133 static void dummy_leds_event(led_event_t evt) 134 { 135 } 136 137 void (*leds_event)(led_event_t) = dummy_leds_event; 138 139 struct leds_evt_name { 140 const char name[8]; 141 int on; 142 int off; 143 }; 144 145 static const struct leds_evt_name evt_names[] = { 146 { "amber", led_amber_on, led_amber_off }, 147 { "blue", led_blue_on, led_blue_off }, 148 { "green", led_green_on, led_green_off }, 149 { "red", led_red_on, led_red_off }, 150 }; 151 152 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size) 153 { 154 int ret = -EINVAL, len = strcspn(buf, " "); 155 156 if (len > 0 && buf[len] == '\0') 157 len--; 158 159 if (strncmp(buf, "claim", len) == 0) { 160 leds_event(led_claim); 161 ret = size; 162 } else if (strncmp(buf, "release", len) == 0) { 163 leds_event(led_release); 164 ret = size; 165 } else { 166 int i; 167 168 for (i = 0; i < ARRAY_SIZE(evt_names); i++) { 169 if (strlen(evt_names[i].name) != len || 170 strncmp(buf, evt_names[i].name, len) != 0) 171 continue; 172 if (strncmp(buf+len, " on", 3) == 0) { 173 leds_event(evt_names[i].on); 174 ret = size; 175 } else if (strncmp(buf+len, " off", 4) == 0) { 176 leds_event(evt_names[i].off); 177 ret = size; 178 } 179 break; 180 } 181 } 182 return ret; 183 } 184 185 static SYSDEV_ATTR(event, 0200, NULL, leds_store); 186 187 static int leds_suspend(struct sys_device *dev, pm_message_t state) 188 { 189 leds_event(led_stop); 190 return 0; 191 } 192 193 static int leds_resume(struct sys_device *dev) 194 { 195 leds_event(led_start); 196 return 0; 197 } 198 199 static int leds_shutdown(struct sys_device *dev) 200 { 201 leds_event(led_halted); 202 return 0; 203 } 204 205 static struct sysdev_class leds_sysclass = { 206 set_kset_name("leds"), 207 .shutdown = leds_shutdown, 208 .suspend = leds_suspend, 209 .resume = leds_resume, 210 }; 211 212 static struct sys_device leds_device = { 213 .id = 0, 214 .cls = &leds_sysclass, 215 }; 216 217 static int __init leds_init(void) 218 { 219 int ret; 220 ret = sysdev_class_register(&leds_sysclass); 221 if (ret == 0) 222 ret = sysdev_register(&leds_device); 223 if (ret == 0) 224 ret = sysdev_create_file(&leds_device, &attr_event); 225 return ret; 226 } 227 228 device_initcall(leds_init); 229 230 EXPORT_SYMBOL(leds_event); 231 #endif 232 233 #ifdef CONFIG_LEDS_TIMER 234 static inline void do_leds(void) 235 { 236 static unsigned int count = HZ/2; 237 238 if (--count == 0) { 239 count = HZ/2; 240 leds_event(led_timer); 241 } 242 } 243 #else 244 #define do_leds() 245 #endif 246 247 #ifndef CONFIG_GENERIC_TIME 248 void do_gettimeofday(struct timeval *tv) 249 { 250 unsigned long flags; 251 unsigned long seq; 252 unsigned long usec, sec; 253 254 do { 255 seq = read_seqbegin_irqsave(&xtime_lock, flags); 256 usec = system_timer->offset(); 257 sec = xtime.tv_sec; 258 usec += xtime.tv_nsec / 1000; 259 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); 260 261 /* usec may have gone up a lot: be safe */ 262 while (usec >= 1000000) { 263 usec -= 1000000; 264 sec++; 265 } 266 267 tv->tv_sec = sec; 268 tv->tv_usec = usec; 269 } 270 271 EXPORT_SYMBOL(do_gettimeofday); 272 273 int do_settimeofday(struct timespec *tv) 274 { 275 time_t wtm_sec, sec = tv->tv_sec; 276 long wtm_nsec, nsec = tv->tv_nsec; 277 278 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) 279 return -EINVAL; 280 281 write_seqlock_irq(&xtime_lock); 282 /* 283 * This is revolting. We need to set "xtime" correctly. However, the 284 * value in this location is the value at the most recent update of 285 * wall time. Discover what correction gettimeofday() would have 286 * done, and then undo it! 287 */ 288 nsec -= system_timer->offset() * NSEC_PER_USEC; 289 290 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); 291 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); 292 293 set_normalized_timespec(&xtime, sec, nsec); 294 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); 295 296 ntp_clear(); 297 write_sequnlock_irq(&xtime_lock); 298 clock_was_set(); 299 return 0; 300 } 301 302 EXPORT_SYMBOL(do_settimeofday); 303 #endif /* !CONFIG_GENERIC_TIME */ 304 305 /** 306 * save_time_delta - Save the offset between system time and RTC time 307 * @delta: pointer to timespec to store delta 308 * @rtc: pointer to timespec for current RTC time 309 * 310 * Return a delta between the system time and the RTC time, such 311 * that system time can be restored later with restore_time_delta() 312 */ 313 void save_time_delta(struct timespec *delta, struct timespec *rtc) 314 { 315 set_normalized_timespec(delta, 316 xtime.tv_sec - rtc->tv_sec, 317 xtime.tv_nsec - rtc->tv_nsec); 318 } 319 EXPORT_SYMBOL(save_time_delta); 320 321 /** 322 * restore_time_delta - Restore the current system time 323 * @delta: delta returned by save_time_delta() 324 * @rtc: pointer to timespec for current RTC time 325 */ 326 void restore_time_delta(struct timespec *delta, struct timespec *rtc) 327 { 328 struct timespec ts; 329 330 set_normalized_timespec(&ts, 331 delta->tv_sec + rtc->tv_sec, 332 delta->tv_nsec + rtc->tv_nsec); 333 334 do_settimeofday(&ts); 335 } 336 EXPORT_SYMBOL(restore_time_delta); 337 338 /* 339 * Kernel system timer support. 340 */ 341 void timer_tick(void) 342 { 343 profile_tick(CPU_PROFILING); 344 do_leds(); 345 do_set_rtc(); 346 do_timer(1); 347 #ifndef CONFIG_SMP 348 update_process_times(user_mode(get_irq_regs())); 349 #endif 350 } 351 352 #ifdef CONFIG_PM 353 static int timer_suspend(struct sys_device *dev, pm_message_t state) 354 { 355 struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 356 357 if (timer->suspend != NULL) 358 timer->suspend(); 359 360 return 0; 361 } 362 363 static int timer_resume(struct sys_device *dev) 364 { 365 struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 366 367 if (timer->resume != NULL) 368 timer->resume(); 369 370 return 0; 371 } 372 #else 373 #define timer_suspend NULL 374 #define timer_resume NULL 375 #endif 376 377 static struct sysdev_class timer_sysclass = { 378 set_kset_name("timer"), 379 .suspend = timer_suspend, 380 .resume = timer_resume, 381 }; 382 383 #ifdef CONFIG_NO_IDLE_HZ 384 static int timer_dyn_tick_enable(void) 385 { 386 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 387 unsigned long flags; 388 int ret = -ENODEV; 389 390 if (dyn_tick) { 391 spin_lock_irqsave(&dyn_tick->lock, flags); 392 ret = 0; 393 if (!(dyn_tick->state & DYN_TICK_ENABLED)) { 394 ret = dyn_tick->enable(); 395 396 if (ret == 0) 397 dyn_tick->state |= DYN_TICK_ENABLED; 398 } 399 spin_unlock_irqrestore(&dyn_tick->lock, flags); 400 } 401 402 return ret; 403 } 404 405 static int timer_dyn_tick_disable(void) 406 { 407 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 408 unsigned long flags; 409 int ret = -ENODEV; 410 411 if (dyn_tick) { 412 spin_lock_irqsave(&dyn_tick->lock, flags); 413 ret = 0; 414 if (dyn_tick->state & DYN_TICK_ENABLED) { 415 ret = dyn_tick->disable(); 416 417 if (ret == 0) 418 dyn_tick->state &= ~DYN_TICK_ENABLED; 419 } 420 spin_unlock_irqrestore(&dyn_tick->lock, flags); 421 } 422 423 return ret; 424 } 425 426 /* 427 * Reprogram the system timer for at least the calculated time interval. 428 * This function should be called from the idle thread with IRQs disabled, 429 * immediately before sleeping. 430 */ 431 void timer_dyn_reprogram(void) 432 { 433 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 434 unsigned long next, seq, flags; 435 436 if (!dyn_tick) 437 return; 438 439 spin_lock_irqsave(&dyn_tick->lock, flags); 440 if (dyn_tick->state & DYN_TICK_ENABLED) { 441 next = next_timer_interrupt(); 442 do { 443 seq = read_seqbegin(&xtime_lock); 444 dyn_tick->reprogram(next - jiffies); 445 } while (read_seqretry(&xtime_lock, seq)); 446 } 447 spin_unlock_irqrestore(&dyn_tick->lock, flags); 448 } 449 450 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf) 451 { 452 return sprintf(buf, "%i\n", 453 (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1); 454 } 455 456 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf, 457 size_t count) 458 { 459 unsigned int enable = simple_strtoul(buf, NULL, 2); 460 461 if (enable) 462 timer_dyn_tick_enable(); 463 else 464 timer_dyn_tick_disable(); 465 466 return count; 467 } 468 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick); 469 470 /* 471 * dyntick=enable|disable 472 */ 473 static char dyntick_str[4] __initdata = ""; 474 475 static int __init dyntick_setup(char *str) 476 { 477 if (str) 478 strlcpy(dyntick_str, str, sizeof(dyntick_str)); 479 return 1; 480 } 481 482 __setup("dyntick=", dyntick_setup); 483 #endif 484 485 static int __init timer_init_sysfs(void) 486 { 487 int ret = sysdev_class_register(&timer_sysclass); 488 if (ret == 0) { 489 system_timer->dev.cls = &timer_sysclass; 490 ret = sysdev_register(&system_timer->dev); 491 } 492 493 #ifdef CONFIG_NO_IDLE_HZ 494 if (ret == 0 && system_timer->dyn_tick) { 495 ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick); 496 497 /* 498 * Turn on dynamic tick after calibrate delay 499 * for correct bogomips 500 */ 501 if (ret == 0 && dyntick_str[0] == 'e') 502 ret = timer_dyn_tick_enable(); 503 } 504 #endif 505 506 return ret; 507 } 508 509 device_initcall(timer_init_sysfs); 510 511 void __init time_init(void) 512 { 513 #ifndef CONFIG_GENERIC_TIME 514 if (system_timer->offset == NULL) 515 system_timer->offset = dummy_gettimeoffset; 516 #endif 517 system_timer->init(); 518 519 #ifdef CONFIG_NO_IDLE_HZ 520 if (system_timer->dyn_tick) 521 system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED; 522 #endif 523 } 524 525