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