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/sched.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 #include <linux/irq.h> 32 33 #include <linux/mc146818rtc.h> 34 35 #include <asm/leds.h> 36 #include <asm/thread_info.h> 37 #include <asm/stacktrace.h> 38 #include <asm/mach/time.h> 39 40 /* 41 * Our system timer. 42 */ 43 struct sys_timer *system_timer; 44 45 #if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE) 46 /* this needs a better home */ 47 DEFINE_SPINLOCK(rtc_lock); 48 49 #ifdef CONFIG_RTC_DRV_CMOS_MODULE 50 EXPORT_SYMBOL(rtc_lock); 51 #endif 52 #endif /* pc-style 'CMOS' RTC support */ 53 54 /* change this if you have some constant time drift */ 55 #define USECS_PER_JIFFY (1000000/HZ) 56 57 #ifdef CONFIG_SMP 58 unsigned long profile_pc(struct pt_regs *regs) 59 { 60 struct stackframe frame; 61 62 if (!in_lock_functions(regs->ARM_pc)) 63 return regs->ARM_pc; 64 65 frame.fp = regs->ARM_fp; 66 frame.sp = regs->ARM_sp; 67 frame.lr = regs->ARM_lr; 68 frame.pc = regs->ARM_pc; 69 do { 70 int ret = unwind_frame(&frame); 71 if (ret < 0) 72 return 0; 73 } while (in_lock_functions(frame.pc)); 74 75 return frame.pc; 76 } 77 EXPORT_SYMBOL(profile_pc); 78 #endif 79 80 /* 81 * hook for setting the RTC's idea of the current time. 82 */ 83 int (*set_rtc)(void); 84 85 #ifndef CONFIG_GENERIC_TIME 86 static unsigned long dummy_gettimeoffset(void) 87 { 88 return 0; 89 } 90 #endif 91 92 static unsigned long next_rtc_update; 93 94 /* 95 * If we have an externally synchronized linux clock, then update 96 * CMOS clock accordingly every ~11 minutes. set_rtc() has to be 97 * called as close as possible to 500 ms before the new second 98 * starts. 99 */ 100 static inline void do_set_rtc(void) 101 { 102 if (!ntp_synced() || set_rtc == NULL) 103 return; 104 105 if (next_rtc_update && 106 time_before((unsigned long)xtime.tv_sec, next_rtc_update)) 107 return; 108 109 if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) && 110 xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1)) 111 return; 112 113 if (set_rtc()) 114 /* 115 * rtc update failed. Try again in 60s 116 */ 117 next_rtc_update = xtime.tv_sec + 60; 118 else 119 next_rtc_update = xtime.tv_sec + 660; 120 } 121 122 #ifdef CONFIG_LEDS 123 124 static void dummy_leds_event(led_event_t evt) 125 { 126 } 127 128 void (*leds_event)(led_event_t) = dummy_leds_event; 129 130 struct leds_evt_name { 131 const char name[8]; 132 int on; 133 int off; 134 }; 135 136 static const struct leds_evt_name evt_names[] = { 137 { "amber", led_amber_on, led_amber_off }, 138 { "blue", led_blue_on, led_blue_off }, 139 { "green", led_green_on, led_green_off }, 140 { "red", led_red_on, led_red_off }, 141 }; 142 143 static ssize_t leds_store(struct sys_device *dev, 144 struct sysdev_attribute *attr, 145 const char *buf, size_t size) 146 { 147 int ret = -EINVAL, len = strcspn(buf, " "); 148 149 if (len > 0 && buf[len] == '\0') 150 len--; 151 152 if (strncmp(buf, "claim", len) == 0) { 153 leds_event(led_claim); 154 ret = size; 155 } else if (strncmp(buf, "release", len) == 0) { 156 leds_event(led_release); 157 ret = size; 158 } else { 159 int i; 160 161 for (i = 0; i < ARRAY_SIZE(evt_names); i++) { 162 if (strlen(evt_names[i].name) != len || 163 strncmp(buf, evt_names[i].name, len) != 0) 164 continue; 165 if (strncmp(buf+len, " on", 3) == 0) { 166 leds_event(evt_names[i].on); 167 ret = size; 168 } else if (strncmp(buf+len, " off", 4) == 0) { 169 leds_event(evt_names[i].off); 170 ret = size; 171 } 172 break; 173 } 174 } 175 return ret; 176 } 177 178 static SYSDEV_ATTR(event, 0200, NULL, leds_store); 179 180 static int leds_suspend(struct sys_device *dev, pm_message_t state) 181 { 182 leds_event(led_stop); 183 return 0; 184 } 185 186 static int leds_resume(struct sys_device *dev) 187 { 188 leds_event(led_start); 189 return 0; 190 } 191 192 static int leds_shutdown(struct sys_device *dev) 193 { 194 leds_event(led_halted); 195 return 0; 196 } 197 198 static struct sysdev_class leds_sysclass = { 199 .name = "leds", 200 .shutdown = leds_shutdown, 201 .suspend = leds_suspend, 202 .resume = leds_resume, 203 }; 204 205 static struct sys_device leds_device = { 206 .id = 0, 207 .cls = &leds_sysclass, 208 }; 209 210 static int __init leds_init(void) 211 { 212 int ret; 213 ret = sysdev_class_register(&leds_sysclass); 214 if (ret == 0) 215 ret = sysdev_register(&leds_device); 216 if (ret == 0) 217 ret = sysdev_create_file(&leds_device, &attr_event); 218 return ret; 219 } 220 221 device_initcall(leds_init); 222 223 EXPORT_SYMBOL(leds_event); 224 #endif 225 226 #ifdef CONFIG_LEDS_TIMER 227 static inline void do_leds(void) 228 { 229 static unsigned int count = HZ/2; 230 231 if (--count == 0) { 232 count = HZ/2; 233 leds_event(led_timer); 234 } 235 } 236 #else 237 #define do_leds() 238 #endif 239 240 #ifndef CONFIG_GENERIC_TIME 241 void do_gettimeofday(struct timeval *tv) 242 { 243 unsigned long flags; 244 unsigned long seq; 245 unsigned long usec, sec; 246 247 do { 248 seq = read_seqbegin_irqsave(&xtime_lock, flags); 249 usec = system_timer->offset(); 250 sec = xtime.tv_sec; 251 usec += xtime.tv_nsec / 1000; 252 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); 253 254 /* usec may have gone up a lot: be safe */ 255 while (usec >= 1000000) { 256 usec -= 1000000; 257 sec++; 258 } 259 260 tv->tv_sec = sec; 261 tv->tv_usec = usec; 262 } 263 264 EXPORT_SYMBOL(do_gettimeofday); 265 266 int do_settimeofday(struct timespec *tv) 267 { 268 time_t wtm_sec, sec = tv->tv_sec; 269 long wtm_nsec, nsec = tv->tv_nsec; 270 271 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) 272 return -EINVAL; 273 274 write_seqlock_irq(&xtime_lock); 275 /* 276 * This is revolting. We need to set "xtime" correctly. However, the 277 * value in this location is the value at the most recent update of 278 * wall time. Discover what correction gettimeofday() would have 279 * done, and then undo it! 280 */ 281 nsec -= system_timer->offset() * NSEC_PER_USEC; 282 283 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); 284 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); 285 286 set_normalized_timespec(&xtime, sec, nsec); 287 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); 288 289 ntp_clear(); 290 write_sequnlock_irq(&xtime_lock); 291 clock_was_set(); 292 return 0; 293 } 294 295 EXPORT_SYMBOL(do_settimeofday); 296 #endif /* !CONFIG_GENERIC_TIME */ 297 298 /** 299 * save_time_delta - Save the offset between system time and RTC time 300 * @delta: pointer to timespec to store delta 301 * @rtc: pointer to timespec for current RTC time 302 * 303 * Return a delta between the system time and the RTC time, such 304 * that system time can be restored later with restore_time_delta() 305 */ 306 void save_time_delta(struct timespec *delta, struct timespec *rtc) 307 { 308 set_normalized_timespec(delta, 309 xtime.tv_sec - rtc->tv_sec, 310 xtime.tv_nsec - rtc->tv_nsec); 311 } 312 EXPORT_SYMBOL(save_time_delta); 313 314 /** 315 * restore_time_delta - Restore the current system time 316 * @delta: delta returned by save_time_delta() 317 * @rtc: pointer to timespec for current RTC time 318 */ 319 void restore_time_delta(struct timespec *delta, struct timespec *rtc) 320 { 321 struct timespec ts; 322 323 set_normalized_timespec(&ts, 324 delta->tv_sec + rtc->tv_sec, 325 delta->tv_nsec + rtc->tv_nsec); 326 327 do_settimeofday(&ts); 328 } 329 EXPORT_SYMBOL(restore_time_delta); 330 331 #ifndef CONFIG_GENERIC_CLOCKEVENTS 332 /* 333 * Kernel system timer support. 334 */ 335 void timer_tick(void) 336 { 337 profile_tick(CPU_PROFILING); 338 do_leds(); 339 do_set_rtc(); 340 write_seqlock(&xtime_lock); 341 do_timer(1); 342 write_sequnlock(&xtime_lock); 343 #ifndef CONFIG_SMP 344 update_process_times(user_mode(get_irq_regs())); 345 #endif 346 } 347 #endif 348 349 #if defined(CONFIG_PM) && !defined(CONFIG_GENERIC_CLOCKEVENTS) 350 static int timer_suspend(struct sys_device *dev, pm_message_t state) 351 { 352 struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 353 354 if (timer->suspend != NULL) 355 timer->suspend(); 356 357 return 0; 358 } 359 360 static int timer_resume(struct sys_device *dev) 361 { 362 struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 363 364 if (timer->resume != NULL) 365 timer->resume(); 366 367 return 0; 368 } 369 #else 370 #define timer_suspend NULL 371 #define timer_resume NULL 372 #endif 373 374 static struct sysdev_class timer_sysclass = { 375 .name = "timer", 376 .suspend = timer_suspend, 377 .resume = timer_resume, 378 }; 379 380 static int __init timer_init_sysfs(void) 381 { 382 int ret = sysdev_class_register(&timer_sysclass); 383 if (ret == 0) { 384 system_timer->dev.cls = &timer_sysclass; 385 ret = sysdev_register(&system_timer->dev); 386 } 387 388 return ret; 389 } 390 391 device_initcall(timer_init_sysfs); 392 393 void __init time_init(void) 394 { 395 #ifndef CONFIG_GENERIC_TIME 396 if (system_timer->offset == NULL) 397 system_timer->offset = dummy_gettimeoffset; 398 #endif 399 system_timer->init(); 400 } 401 402