Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 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 | u64 jiffies_64 = INITIAL_JIFFIES; |
| 40 | |
| 41 | EXPORT_SYMBOL(jiffies_64); |
| 42 | |
| 43 | /* |
| 44 | * Our system timer. |
| 45 | */ |
| 46 | struct sys_timer *system_timer; |
| 47 | |
| 48 | extern unsigned long wall_jiffies; |
| 49 | |
| 50 | /* this needs a better home */ |
| 51 | DEFINE_SPINLOCK(rtc_lock); |
| 52 | |
| 53 | #ifdef CONFIG_SA1100_RTC_MODULE |
| 54 | EXPORT_SYMBOL(rtc_lock); |
| 55 | #endif |
| 56 | |
| 57 | /* change this if you have some constant time drift */ |
| 58 | #define USECS_PER_JIFFY (1000000/HZ) |
| 59 | |
| 60 | #ifdef CONFIG_SMP |
| 61 | unsigned long profile_pc(struct pt_regs *regs) |
| 62 | { |
| 63 | unsigned long fp, pc = instruction_pointer(regs); |
| 64 | |
| 65 | if (in_lock_functions(pc)) { |
| 66 | fp = regs->ARM_fp; |
| 67 | pc = pc_pointer(((unsigned long *)fp)[-1]); |
| 68 | } |
| 69 | |
| 70 | return pc; |
| 71 | } |
| 72 | EXPORT_SYMBOL(profile_pc); |
| 73 | #endif |
| 74 | |
| 75 | /* |
| 76 | * hook for setting the RTC's idea of the current time. |
| 77 | */ |
| 78 | int (*set_rtc)(void); |
| 79 | |
| 80 | static unsigned long dummy_gettimeoffset(void) |
| 81 | { |
| 82 | return 0; |
| 83 | } |
| 84 | |
| 85 | /* |
| 86 | * Scheduler clock - returns current time in nanosec units. |
| 87 | * This is the default implementation. Sub-architecture |
| 88 | * implementations can override this. |
| 89 | */ |
| 90 | unsigned long long __attribute__((weak)) sched_clock(void) |
| 91 | { |
| 92 | return (unsigned long long)jiffies * (1000000000 / HZ); |
| 93 | } |
| 94 | |
| 95 | static unsigned long next_rtc_update; |
| 96 | |
| 97 | /* |
| 98 | * If we have an externally synchronized linux clock, then update |
| 99 | * CMOS clock accordingly every ~11 minutes. set_rtc() has to be |
| 100 | * called as close as possible to 500 ms before the new second |
| 101 | * starts. |
| 102 | */ |
| 103 | static inline void do_set_rtc(void) |
| 104 | { |
| 105 | if (time_status & STA_UNSYNC || set_rtc == NULL) |
| 106 | return; |
| 107 | |
| 108 | if (next_rtc_update && |
| 109 | time_before((unsigned long)xtime.tv_sec, next_rtc_update)) |
| 110 | return; |
| 111 | |
| 112 | if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) && |
| 113 | xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1)) |
| 114 | return; |
| 115 | |
| 116 | if (set_rtc()) |
| 117 | /* |
| 118 | * rtc update failed. Try again in 60s |
| 119 | */ |
| 120 | next_rtc_update = xtime.tv_sec + 60; |
| 121 | else |
| 122 | next_rtc_update = xtime.tv_sec + 660; |
| 123 | } |
| 124 | |
| 125 | #ifdef CONFIG_LEDS |
| 126 | |
| 127 | static void dummy_leds_event(led_event_t evt) |
| 128 | { |
| 129 | } |
| 130 | |
| 131 | void (*leds_event)(led_event_t) = dummy_leds_event; |
| 132 | |
| 133 | struct leds_evt_name { |
| 134 | const char name[8]; |
| 135 | int on; |
| 136 | int off; |
| 137 | }; |
| 138 | |
| 139 | static const struct leds_evt_name evt_names[] = { |
| 140 | { "amber", led_amber_on, led_amber_off }, |
| 141 | { "blue", led_blue_on, led_blue_off }, |
| 142 | { "green", led_green_on, led_green_off }, |
| 143 | { "red", led_red_on, led_red_off }, |
| 144 | }; |
| 145 | |
| 146 | static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size) |
| 147 | { |
| 148 | int ret = -EINVAL, len = strcspn(buf, " "); |
| 149 | |
| 150 | if (len > 0 && buf[len] == '\0') |
| 151 | len--; |
| 152 | |
| 153 | if (strncmp(buf, "claim", len) == 0) { |
| 154 | leds_event(led_claim); |
| 155 | ret = size; |
| 156 | } else if (strncmp(buf, "release", len) == 0) { |
| 157 | leds_event(led_release); |
| 158 | ret = size; |
| 159 | } else { |
| 160 | int i; |
| 161 | |
| 162 | for (i = 0; i < ARRAY_SIZE(evt_names); i++) { |
| 163 | if (strlen(evt_names[i].name) != len || |
| 164 | strncmp(buf, evt_names[i].name, len) != 0) |
| 165 | continue; |
| 166 | if (strncmp(buf+len, " on", 3) == 0) { |
| 167 | leds_event(evt_names[i].on); |
| 168 | ret = size; |
| 169 | } else if (strncmp(buf+len, " off", 4) == 0) { |
| 170 | leds_event(evt_names[i].off); |
| 171 | ret = size; |
| 172 | } |
| 173 | break; |
| 174 | } |
| 175 | } |
| 176 | return ret; |
| 177 | } |
| 178 | |
| 179 | static SYSDEV_ATTR(event, 0200, NULL, leds_store); |
| 180 | |
| 181 | static int leds_suspend(struct sys_device *dev, pm_message_t state) |
| 182 | { |
| 183 | leds_event(led_stop); |
| 184 | return 0; |
| 185 | } |
| 186 | |
| 187 | static int leds_resume(struct sys_device *dev) |
| 188 | { |
| 189 | leds_event(led_start); |
| 190 | return 0; |
| 191 | } |
| 192 | |
| 193 | static int leds_shutdown(struct sys_device *dev) |
| 194 | { |
| 195 | leds_event(led_halted); |
| 196 | return 0; |
| 197 | } |
| 198 | |
| 199 | static struct sysdev_class leds_sysclass = { |
| 200 | set_kset_name("leds"), |
| 201 | .shutdown = leds_shutdown, |
| 202 | .suspend = leds_suspend, |
| 203 | .resume = leds_resume, |
| 204 | }; |
| 205 | |
| 206 | static struct sys_device leds_device = { |
| 207 | .id = 0, |
| 208 | .cls = &leds_sysclass, |
| 209 | }; |
| 210 | |
| 211 | static int __init leds_init(void) |
| 212 | { |
| 213 | int ret; |
| 214 | ret = sysdev_class_register(&leds_sysclass); |
| 215 | if (ret == 0) |
| 216 | ret = sysdev_register(&leds_device); |
| 217 | if (ret == 0) |
| 218 | ret = sysdev_create_file(&leds_device, &attr_event); |
| 219 | return ret; |
| 220 | } |
| 221 | |
| 222 | device_initcall(leds_init); |
| 223 | |
| 224 | EXPORT_SYMBOL(leds_event); |
| 225 | #endif |
| 226 | |
| 227 | #ifdef CONFIG_LEDS_TIMER |
| 228 | static inline void do_leds(void) |
| 229 | { |
| 230 | static unsigned int count = 50; |
| 231 | |
| 232 | if (--count == 0) { |
| 233 | count = 50; |
| 234 | leds_event(led_timer); |
| 235 | } |
| 236 | } |
| 237 | #else |
| 238 | #define do_leds() |
| 239 | #endif |
| 240 | |
| 241 | void do_gettimeofday(struct timeval *tv) |
| 242 | { |
| 243 | unsigned long flags; |
| 244 | unsigned long seq; |
| 245 | unsigned long usec, sec, lost; |
| 246 | |
| 247 | do { |
| 248 | seq = read_seqbegin_irqsave(&xtime_lock, flags); |
| 249 | usec = system_timer->offset(); |
| 250 | |
| 251 | lost = jiffies - wall_jiffies; |
| 252 | if (lost) |
| 253 | usec += lost * USECS_PER_JIFFY; |
| 254 | |
| 255 | sec = xtime.tv_sec; |
| 256 | usec += xtime.tv_nsec / 1000; |
| 257 | } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); |
| 258 | |
| 259 | /* usec may have gone up a lot: be safe */ |
| 260 | while (usec >= 1000000) { |
| 261 | usec -= 1000000; |
| 262 | sec++; |
| 263 | } |
| 264 | |
| 265 | tv->tv_sec = sec; |
| 266 | tv->tv_usec = usec; |
| 267 | } |
| 268 | |
| 269 | EXPORT_SYMBOL(do_gettimeofday); |
| 270 | |
| 271 | int do_settimeofday(struct timespec *tv) |
| 272 | { |
| 273 | time_t wtm_sec, sec = tv->tv_sec; |
| 274 | long wtm_nsec, nsec = tv->tv_nsec; |
| 275 | |
| 276 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) |
| 277 | return -EINVAL; |
| 278 | |
| 279 | write_seqlock_irq(&xtime_lock); |
| 280 | /* |
| 281 | * This is revolting. We need to set "xtime" correctly. However, the |
| 282 | * value in this location is the value at the most recent update of |
| 283 | * wall time. Discover what correction gettimeofday() would have |
| 284 | * done, and then undo it! |
| 285 | */ |
| 286 | nsec -= system_timer->offset() * NSEC_PER_USEC; |
| 287 | nsec -= (jiffies - wall_jiffies) * TICK_NSEC; |
| 288 | |
| 289 | wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); |
| 290 | wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); |
| 291 | |
| 292 | set_normalized_timespec(&xtime, sec, nsec); |
| 293 | set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); |
| 294 | |
| 295 | time_adjust = 0; /* stop active adjtime() */ |
| 296 | time_status |= STA_UNSYNC; |
| 297 | time_maxerror = NTP_PHASE_LIMIT; |
| 298 | time_esterror = NTP_PHASE_LIMIT; |
| 299 | write_sequnlock_irq(&xtime_lock); |
| 300 | clock_was_set(); |
| 301 | return 0; |
| 302 | } |
| 303 | |
| 304 | EXPORT_SYMBOL(do_settimeofday); |
| 305 | |
| 306 | /** |
| 307 | * save_time_delta - Save the offset between system time and RTC time |
| 308 | * @delta: pointer to timespec to store delta |
| 309 | * @rtc: pointer to timespec for current RTC time |
| 310 | * |
| 311 | * Return a delta between the system time and the RTC time, such |
| 312 | * that system time can be restored later with restore_time_delta() |
| 313 | */ |
| 314 | void save_time_delta(struct timespec *delta, struct timespec *rtc) |
| 315 | { |
| 316 | set_normalized_timespec(delta, |
| 317 | xtime.tv_sec - rtc->tv_sec, |
| 318 | xtime.tv_nsec - rtc->tv_nsec); |
| 319 | } |
| 320 | EXPORT_SYMBOL(save_time_delta); |
| 321 | |
| 322 | /** |
| 323 | * restore_time_delta - Restore the current system time |
| 324 | * @delta: delta returned by save_time_delta() |
| 325 | * @rtc: pointer to timespec for current RTC time |
| 326 | */ |
| 327 | void restore_time_delta(struct timespec *delta, struct timespec *rtc) |
| 328 | { |
| 329 | struct timespec ts; |
| 330 | |
| 331 | set_normalized_timespec(&ts, |
| 332 | delta->tv_sec + rtc->tv_sec, |
| 333 | delta->tv_nsec + rtc->tv_nsec); |
| 334 | |
| 335 | do_settimeofday(&ts); |
| 336 | } |
| 337 | EXPORT_SYMBOL(restore_time_delta); |
| 338 | |
| 339 | /* |
| 340 | * Kernel system timer support. |
| 341 | */ |
| 342 | void timer_tick(struct pt_regs *regs) |
| 343 | { |
| 344 | profile_tick(CPU_PROFILING, regs); |
| 345 | do_leds(); |
| 346 | do_set_rtc(); |
| 347 | do_timer(regs); |
| 348 | #ifndef CONFIG_SMP |
| 349 | update_process_times(user_mode(regs)); |
| 350 | #endif |
| 351 | } |
| 352 | |
| 353 | #ifdef CONFIG_PM |
| 354 | static int timer_suspend(struct sys_device *dev, pm_message_t state) |
| 355 | { |
| 356 | struct sys_timer *timer = container_of(dev, struct sys_timer, dev); |
| 357 | |
| 358 | if (timer->suspend != NULL) |
| 359 | timer->suspend(); |
| 360 | |
| 361 | return 0; |
| 362 | } |
| 363 | |
| 364 | static int timer_resume(struct sys_device *dev) |
| 365 | { |
| 366 | struct sys_timer *timer = container_of(dev, struct sys_timer, dev); |
| 367 | |
| 368 | if (timer->resume != NULL) |
| 369 | timer->resume(); |
| 370 | |
| 371 | return 0; |
| 372 | } |
| 373 | #else |
| 374 | #define timer_suspend NULL |
| 375 | #define timer_resume NULL |
| 376 | #endif |
| 377 | |
| 378 | static struct sysdev_class timer_sysclass = { |
| 379 | set_kset_name("timer"), |
| 380 | .suspend = timer_suspend, |
| 381 | .resume = timer_resume, |
| 382 | }; |
| 383 | |
| 384 | static int __init timer_init_sysfs(void) |
| 385 | { |
| 386 | int ret = sysdev_class_register(&timer_sysclass); |
| 387 | if (ret == 0) { |
| 388 | system_timer->dev.cls = &timer_sysclass; |
| 389 | ret = sysdev_register(&system_timer->dev); |
| 390 | } |
| 391 | return ret; |
| 392 | } |
| 393 | |
| 394 | device_initcall(timer_init_sysfs); |
| 395 | |
| 396 | void __init time_init(void) |
| 397 | { |
| 398 | if (system_timer->offset == NULL) |
| 399 | system_timer->offset = dummy_gettimeoffset; |
| 400 | system_timer->init(); |
| 401 | } |
| 402 | |