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