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