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 31 #include <asm/leds.h> 32 #include <asm/thread_info.h> 33 #include <asm/mach/time.h> 34 35 /* 36 * Our system timer. 37 */ 38 struct sys_timer *system_timer; 39 40 extern unsigned long wall_jiffies; 41 42 /* this needs a better home */ 43 DEFINE_SPINLOCK(rtc_lock); 44 45 #ifdef CONFIG_SA1100_RTC_MODULE 46 EXPORT_SYMBOL(rtc_lock); 47 #endif 48 49 /* change this if you have some constant time drift */ 50 #define USECS_PER_JIFFY (1000000/HZ) 51 52 #ifdef CONFIG_SMP 53 unsigned long profile_pc(struct pt_regs *regs) 54 { 55 unsigned long fp, pc = instruction_pointer(regs); 56 57 if (in_lock_functions(pc)) { 58 fp = regs->ARM_fp; 59 pc = pc_pointer(((unsigned long *)fp)[-1]); 60 } 61 62 return pc; 63 } 64 EXPORT_SYMBOL(profile_pc); 65 #endif 66 67 /* 68 * hook for setting the RTC's idea of the current time. 69 */ 70 int (*set_rtc)(void); 71 72 static unsigned long dummy_gettimeoffset(void) 73 { 74 return 0; 75 } 76 77 /* 78 * Scheduler clock - returns current time in nanosec units. 79 * This is the default implementation. Sub-architecture 80 * implementations can override this. 81 */ 82 unsigned long long __attribute__((weak)) sched_clock(void) 83 { 84 return (unsigned long long)jiffies * (1000000000 / HZ); 85 } 86 87 static unsigned long next_rtc_update; 88 89 /* 90 * If we have an externally synchronized linux clock, then update 91 * CMOS clock accordingly every ~11 minutes. set_rtc() has to be 92 * called as close as possible to 500 ms before the new second 93 * starts. 94 */ 95 static inline void do_set_rtc(void) 96 { 97 if (!ntp_synced() || set_rtc == NULL) 98 return; 99 100 if (next_rtc_update && 101 time_before((unsigned long)xtime.tv_sec, next_rtc_update)) 102 return; 103 104 if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) && 105 xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1)) 106 return; 107 108 if (set_rtc()) 109 /* 110 * rtc update failed. Try again in 60s 111 */ 112 next_rtc_update = xtime.tv_sec + 60; 113 else 114 next_rtc_update = xtime.tv_sec + 660; 115 } 116 117 #ifdef CONFIG_LEDS 118 119 static void dummy_leds_event(led_event_t evt) 120 { 121 } 122 123 void (*leds_event)(led_event_t) = dummy_leds_event; 124 125 struct leds_evt_name { 126 const char name[8]; 127 int on; 128 int off; 129 }; 130 131 static const struct leds_evt_name evt_names[] = { 132 { "amber", led_amber_on, led_amber_off }, 133 { "blue", led_blue_on, led_blue_off }, 134 { "green", led_green_on, led_green_off }, 135 { "red", led_red_on, led_red_off }, 136 }; 137 138 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size) 139 { 140 int ret = -EINVAL, len = strcspn(buf, " "); 141 142 if (len > 0 && buf[len] == '\0') 143 len--; 144 145 if (strncmp(buf, "claim", len) == 0) { 146 leds_event(led_claim); 147 ret = size; 148 } else if (strncmp(buf, "release", len) == 0) { 149 leds_event(led_release); 150 ret = size; 151 } else { 152 int i; 153 154 for (i = 0; i < ARRAY_SIZE(evt_names); i++) { 155 if (strlen(evt_names[i].name) != len || 156 strncmp(buf, evt_names[i].name, len) != 0) 157 continue; 158 if (strncmp(buf+len, " on", 3) == 0) { 159 leds_event(evt_names[i].on); 160 ret = size; 161 } else if (strncmp(buf+len, " off", 4) == 0) { 162 leds_event(evt_names[i].off); 163 ret = size; 164 } 165 break; 166 } 167 } 168 return ret; 169 } 170 171 static SYSDEV_ATTR(event, 0200, NULL, leds_store); 172 173 static int leds_suspend(struct sys_device *dev, pm_message_t state) 174 { 175 leds_event(led_stop); 176 return 0; 177 } 178 179 static int leds_resume(struct sys_device *dev) 180 { 181 leds_event(led_start); 182 return 0; 183 } 184 185 static int leds_shutdown(struct sys_device *dev) 186 { 187 leds_event(led_halted); 188 return 0; 189 } 190 191 static struct sysdev_class leds_sysclass = { 192 set_kset_name("leds"), 193 .shutdown = leds_shutdown, 194 .suspend = leds_suspend, 195 .resume = leds_resume, 196 }; 197 198 static struct sys_device leds_device = { 199 .id = 0, 200 .cls = &leds_sysclass, 201 }; 202 203 static int __init leds_init(void) 204 { 205 int ret; 206 ret = sysdev_class_register(&leds_sysclass); 207 if (ret == 0) 208 ret = sysdev_register(&leds_device); 209 if (ret == 0) 210 ret = sysdev_create_file(&leds_device, &attr_event); 211 return ret; 212 } 213 214 device_initcall(leds_init); 215 216 EXPORT_SYMBOL(leds_event); 217 #endif 218 219 #ifdef CONFIG_LEDS_TIMER 220 static inline void do_leds(void) 221 { 222 static unsigned int count = 50; 223 224 if (--count == 0) { 225 count = 50; 226 leds_event(led_timer); 227 } 228 } 229 #else 230 #define do_leds() 231 #endif 232 233 void do_gettimeofday(struct timeval *tv) 234 { 235 unsigned long flags; 236 unsigned long seq; 237 unsigned long usec, sec, lost; 238 239 do { 240 seq = read_seqbegin_irqsave(&xtime_lock, flags); 241 usec = system_timer->offset(); 242 243 lost = jiffies - wall_jiffies; 244 if (lost) 245 usec += lost * USECS_PER_JIFFY; 246 247 sec = xtime.tv_sec; 248 usec += xtime.tv_nsec / 1000; 249 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); 250 251 /* usec may have gone up a lot: be safe */ 252 while (usec >= 1000000) { 253 usec -= 1000000; 254 sec++; 255 } 256 257 tv->tv_sec = sec; 258 tv->tv_usec = usec; 259 } 260 261 EXPORT_SYMBOL(do_gettimeofday); 262 263 int do_settimeofday(struct timespec *tv) 264 { 265 time_t wtm_sec, sec = tv->tv_sec; 266 long wtm_nsec, nsec = tv->tv_nsec; 267 268 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) 269 return -EINVAL; 270 271 write_seqlock_irq(&xtime_lock); 272 /* 273 * This is revolting. We need to set "xtime" correctly. However, the 274 * value in this location is the value at the most recent update of 275 * wall time. Discover what correction gettimeofday() would have 276 * done, and then undo it! 277 */ 278 nsec -= system_timer->offset() * NSEC_PER_USEC; 279 nsec -= (jiffies - wall_jiffies) * TICK_NSEC; 280 281 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); 282 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); 283 284 set_normalized_timespec(&xtime, sec, nsec); 285 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); 286 287 ntp_clear(); 288 write_sequnlock_irq(&xtime_lock); 289 clock_was_set(); 290 return 0; 291 } 292 293 EXPORT_SYMBOL(do_settimeofday); 294 295 /** 296 * save_time_delta - Save the offset between system time and RTC time 297 * @delta: pointer to timespec to store delta 298 * @rtc: pointer to timespec for current RTC time 299 * 300 * Return a delta between the system time and the RTC time, such 301 * that system time can be restored later with restore_time_delta() 302 */ 303 void save_time_delta(struct timespec *delta, struct timespec *rtc) 304 { 305 set_normalized_timespec(delta, 306 xtime.tv_sec - rtc->tv_sec, 307 xtime.tv_nsec - rtc->tv_nsec); 308 } 309 EXPORT_SYMBOL(save_time_delta); 310 311 /** 312 * restore_time_delta - Restore the current system time 313 * @delta: delta returned by save_time_delta() 314 * @rtc: pointer to timespec for current RTC time 315 */ 316 void restore_time_delta(struct timespec *delta, struct timespec *rtc) 317 { 318 struct timespec ts; 319 320 set_normalized_timespec(&ts, 321 delta->tv_sec + rtc->tv_sec, 322 delta->tv_nsec + rtc->tv_nsec); 323 324 do_settimeofday(&ts); 325 } 326 EXPORT_SYMBOL(restore_time_delta); 327 328 /* 329 * Kernel system timer support. 330 */ 331 void timer_tick(struct pt_regs *regs) 332 { 333 profile_tick(CPU_PROFILING, regs); 334 do_leds(); 335 do_set_rtc(); 336 do_timer(regs); 337 #ifndef CONFIG_SMP 338 update_process_times(user_mode(regs)); 339 #endif 340 } 341 342 #ifdef CONFIG_PM 343 static int timer_suspend(struct sys_device *dev, pm_message_t state) 344 { 345 struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 346 347 if (timer->suspend != NULL) 348 timer->suspend(); 349 350 return 0; 351 } 352 353 static int timer_resume(struct sys_device *dev) 354 { 355 struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 356 357 if (timer->resume != NULL) 358 timer->resume(); 359 360 return 0; 361 } 362 #else 363 #define timer_suspend NULL 364 #define timer_resume NULL 365 #endif 366 367 static struct sysdev_class timer_sysclass = { 368 set_kset_name("timer"), 369 .suspend = timer_suspend, 370 .resume = timer_resume, 371 }; 372 373 #ifdef CONFIG_NO_IDLE_HZ 374 static int timer_dyn_tick_enable(void) 375 { 376 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 377 unsigned long flags; 378 int ret = -ENODEV; 379 380 if (dyn_tick) { 381 spin_lock_irqsave(&dyn_tick->lock, flags); 382 ret = 0; 383 if (!(dyn_tick->state & DYN_TICK_ENABLED)) { 384 ret = dyn_tick->enable(); 385 386 if (ret == 0) 387 dyn_tick->state |= DYN_TICK_ENABLED; 388 } 389 spin_unlock_irqrestore(&dyn_tick->lock, flags); 390 } 391 392 return ret; 393 } 394 395 static int timer_dyn_tick_disable(void) 396 { 397 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 398 unsigned long flags; 399 int ret = -ENODEV; 400 401 if (dyn_tick) { 402 spin_lock_irqsave(&dyn_tick->lock, flags); 403 ret = 0; 404 if (dyn_tick->state & DYN_TICK_ENABLED) { 405 ret = dyn_tick->disable(); 406 407 if (ret == 0) 408 dyn_tick->state &= ~DYN_TICK_ENABLED; 409 } 410 spin_unlock_irqrestore(&dyn_tick->lock, flags); 411 } 412 413 return ret; 414 } 415 416 /* 417 * Reprogram the system timer for at least the calculated time interval. 418 * This function should be called from the idle thread with IRQs disabled, 419 * immediately before sleeping. 420 */ 421 void timer_dyn_reprogram(void) 422 { 423 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick; 424 unsigned long next, seq, flags; 425 426 if (!dyn_tick) 427 return; 428 429 spin_lock_irqsave(&dyn_tick->lock, flags); 430 if (dyn_tick->state & DYN_TICK_ENABLED) { 431 next = next_timer_interrupt(); 432 do { 433 seq = read_seqbegin(&xtime_lock); 434 dyn_tick->reprogram(next - jiffies); 435 } while (read_seqretry(&xtime_lock, seq)); 436 } 437 spin_unlock_irqrestore(&dyn_tick->lock, flags); 438 } 439 440 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf) 441 { 442 return sprintf(buf, "%i\n", 443 (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1); 444 } 445 446 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf, 447 size_t count) 448 { 449 unsigned int enable = simple_strtoul(buf, NULL, 2); 450 451 if (enable) 452 timer_dyn_tick_enable(); 453 else 454 timer_dyn_tick_disable(); 455 456 return count; 457 } 458 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick); 459 460 /* 461 * dyntick=enable|disable 462 */ 463 static char dyntick_str[4] __initdata = ""; 464 465 static int __init dyntick_setup(char *str) 466 { 467 if (str) 468 strlcpy(dyntick_str, str, sizeof(dyntick_str)); 469 return 1; 470 } 471 472 __setup("dyntick=", dyntick_setup); 473 #endif 474 475 static int __init timer_init_sysfs(void) 476 { 477 int ret = sysdev_class_register(&timer_sysclass); 478 if (ret == 0) { 479 system_timer->dev.cls = &timer_sysclass; 480 ret = sysdev_register(&system_timer->dev); 481 } 482 483 #ifdef CONFIG_NO_IDLE_HZ 484 if (ret == 0 && system_timer->dyn_tick) { 485 ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick); 486 487 /* 488 * Turn on dynamic tick after calibrate delay 489 * for correct bogomips 490 */ 491 if (ret == 0 && dyntick_str[0] == 'e') 492 ret = timer_dyn_tick_enable(); 493 } 494 #endif 495 496 return ret; 497 } 498 499 device_initcall(timer_init_sysfs); 500 501 void __init time_init(void) 502 { 503 if (system_timer->offset == NULL) 504 system_timer->offset = dummy_gettimeoffset; 505 system_timer->init(); 506 507 #ifdef CONFIG_NO_IDLE_HZ 508 if (system_timer->dyn_tick) 509 system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED; 510 #endif 511 } 512 513