Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2001 MontaVista Software Inc. |
| 3 | * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net |
| 4 | * Copyright (c) 2003, 2004 Maciej W. Rozycki |
| 5 | * |
| 6 | * Common time service routines for MIPS machines. See |
| 7 | * Documentation/mips/time.README. |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify it |
| 10 | * under the terms of the GNU General Public License as published by the |
| 11 | * Free Software Foundation; either version 2 of the License, or (at your |
| 12 | * option) any later version. |
| 13 | */ |
Pete Popov | bdf21b1 | 2005-07-14 17:47:57 +0000 | [diff] [blame] | 14 | #include <linux/config.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | #include <linux/types.h> |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/init.h> |
| 18 | #include <linux/sched.h> |
| 19 | #include <linux/param.h> |
| 20 | #include <linux/time.h> |
| 21 | #include <linux/timex.h> |
| 22 | #include <linux/smp.h> |
| 23 | #include <linux/kernel_stat.h> |
| 24 | #include <linux/spinlock.h> |
| 25 | #include <linux/interrupt.h> |
| 26 | #include <linux/module.h> |
| 27 | |
| 28 | #include <asm/bootinfo.h> |
Ralf Baechle | ec74e36 | 2005-07-13 11:48:45 +0000 | [diff] [blame] | 29 | #include <asm/cache.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | #include <asm/compiler.h> |
| 31 | #include <asm/cpu.h> |
| 32 | #include <asm/cpu-features.h> |
| 33 | #include <asm/div64.h> |
| 34 | #include <asm/sections.h> |
| 35 | #include <asm/time.h> |
| 36 | |
| 37 | /* |
| 38 | * The integer part of the number of usecs per jiffy is taken from tick, |
| 39 | * but the fractional part is not recorded, so we calculate it using the |
| 40 | * initial value of HZ. This aids systems where tick isn't really an |
| 41 | * integer (e.g. for HZ = 128). |
| 42 | */ |
| 43 | #define USECS_PER_JIFFY TICK_SIZE |
| 44 | #define USECS_PER_JIFFY_FRAC ((unsigned long)(u32)((1000000ULL << 32) / HZ)) |
| 45 | |
| 46 | #define TICK_SIZE (tick_nsec / 1000) |
| 47 | |
| 48 | u64 jiffies_64 = INITIAL_JIFFIES; |
| 49 | |
| 50 | EXPORT_SYMBOL(jiffies_64); |
| 51 | |
| 52 | /* |
| 53 | * forward reference |
| 54 | */ |
| 55 | extern volatile unsigned long wall_jiffies; |
| 56 | |
| 57 | DEFINE_SPINLOCK(rtc_lock); |
| 58 | |
| 59 | /* |
| 60 | * By default we provide the null RTC ops |
| 61 | */ |
| 62 | static unsigned long null_rtc_get_time(void) |
| 63 | { |
| 64 | return mktime(2000, 1, 1, 0, 0, 0); |
| 65 | } |
| 66 | |
| 67 | static int null_rtc_set_time(unsigned long sec) |
| 68 | { |
| 69 | return 0; |
| 70 | } |
| 71 | |
| 72 | unsigned long (*rtc_get_time)(void) = null_rtc_get_time; |
| 73 | int (*rtc_set_time)(unsigned long) = null_rtc_set_time; |
| 74 | int (*rtc_set_mmss)(unsigned long); |
| 75 | |
| 76 | |
| 77 | /* usecs per counter cycle, shifted to left by 32 bits */ |
| 78 | static unsigned int sll32_usecs_per_cycle; |
| 79 | |
| 80 | /* how many counter cycles in a jiffy */ |
Ralf Baechle | ec74e36 | 2005-07-13 11:48:45 +0000 | [diff] [blame] | 81 | static unsigned long cycles_per_jiffy __read_mostly; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | |
| 83 | /* Cycle counter value at the previous timer interrupt.. */ |
| 84 | static unsigned int timerhi, timerlo; |
| 85 | |
| 86 | /* expirelo is the count value for next CPU timer interrupt */ |
| 87 | static unsigned int expirelo; |
| 88 | |
| 89 | |
| 90 | /* |
| 91 | * Null timer ack for systems not needing one (e.g. i8254). |
| 92 | */ |
| 93 | static void null_timer_ack(void) { /* nothing */ } |
| 94 | |
| 95 | /* |
| 96 | * Null high precision timer functions for systems lacking one. |
| 97 | */ |
| 98 | static unsigned int null_hpt_read(void) |
| 99 | { |
| 100 | return 0; |
| 101 | } |
| 102 | |
Ralf Baechle | ec74e36 | 2005-07-13 11:48:45 +0000 | [diff] [blame] | 103 | static void null_hpt_init(unsigned int count) |
| 104 | { |
| 105 | /* nothing */ |
| 106 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 107 | |
| 108 | |
| 109 | /* |
| 110 | * Timer ack for an R4k-compatible timer of a known frequency. |
| 111 | */ |
| 112 | static void c0_timer_ack(void) |
| 113 | { |
| 114 | unsigned int count; |
| 115 | |
Pete Popov | bdf21b1 | 2005-07-14 17:47:57 +0000 | [diff] [blame] | 116 | #ifndef CONFIG_SOC_PNX8550 /* pnx8550 resets to zero */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | /* Ack this timer interrupt and set the next one. */ |
| 118 | expirelo += cycles_per_jiffy; |
Pete Popov | bdf21b1 | 2005-07-14 17:47:57 +0000 | [diff] [blame] | 119 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | write_c0_compare(expirelo); |
| 121 | |
| 122 | /* Check to see if we have missed any timer interrupts. */ |
| 123 | count = read_c0_count(); |
| 124 | if ((count - expirelo) < 0x7fffffff) { |
| 125 | /* missed_timer_count++; */ |
| 126 | expirelo = count + cycles_per_jiffy; |
| 127 | write_c0_compare(expirelo); |
| 128 | } |
| 129 | } |
| 130 | |
| 131 | /* |
| 132 | * High precision timer functions for a R4k-compatible timer. |
| 133 | */ |
| 134 | static unsigned int c0_hpt_read(void) |
| 135 | { |
| 136 | return read_c0_count(); |
| 137 | } |
| 138 | |
| 139 | /* For use solely as a high precision timer. */ |
| 140 | static void c0_hpt_init(unsigned int count) |
| 141 | { |
| 142 | write_c0_count(read_c0_count() - count); |
| 143 | } |
| 144 | |
| 145 | /* For use both as a high precision timer and an interrupt source. */ |
| 146 | static void c0_hpt_timer_init(unsigned int count) |
| 147 | { |
| 148 | count = read_c0_count() - count; |
| 149 | expirelo = (count / cycles_per_jiffy + 1) * cycles_per_jiffy; |
| 150 | write_c0_count(expirelo - cycles_per_jiffy); |
| 151 | write_c0_compare(expirelo); |
| 152 | write_c0_count(count); |
| 153 | } |
| 154 | |
| 155 | int (*mips_timer_state)(void); |
| 156 | void (*mips_timer_ack)(void); |
| 157 | unsigned int (*mips_hpt_read)(void); |
| 158 | void (*mips_hpt_init)(unsigned int); |
| 159 | |
| 160 | |
| 161 | /* |
| 162 | * This version of gettimeofday has microsecond resolution and better than |
| 163 | * microsecond precision on fast machines with cycle counter. |
| 164 | */ |
| 165 | void do_gettimeofday(struct timeval *tv) |
| 166 | { |
| 167 | unsigned long seq; |
| 168 | unsigned long lost; |
| 169 | unsigned long usec, sec; |
| 170 | unsigned long max_ntp_tick = tick_usec - tickadj; |
| 171 | |
| 172 | do { |
| 173 | seq = read_seqbegin(&xtime_lock); |
| 174 | |
| 175 | usec = do_gettimeoffset(); |
| 176 | |
| 177 | lost = jiffies - wall_jiffies; |
| 178 | |
| 179 | /* |
| 180 | * If time_adjust is negative then NTP is slowing the clock |
| 181 | * so make sure not to go into next possible interval. |
| 182 | * Better to lose some accuracy than have time go backwards.. |
| 183 | */ |
| 184 | if (unlikely(time_adjust < 0)) { |
| 185 | usec = min(usec, max_ntp_tick); |
| 186 | |
| 187 | if (lost) |
| 188 | usec += lost * max_ntp_tick; |
| 189 | } else if (unlikely(lost)) |
| 190 | usec += lost * tick_usec; |
| 191 | |
| 192 | sec = xtime.tv_sec; |
| 193 | usec += (xtime.tv_nsec / 1000); |
| 194 | |
| 195 | } while (read_seqretry(&xtime_lock, seq)); |
| 196 | |
| 197 | while (usec >= 1000000) { |
| 198 | usec -= 1000000; |
| 199 | sec++; |
| 200 | } |
| 201 | |
| 202 | tv->tv_sec = sec; |
| 203 | tv->tv_usec = usec; |
| 204 | } |
| 205 | |
| 206 | EXPORT_SYMBOL(do_gettimeofday); |
| 207 | |
| 208 | int do_settimeofday(struct timespec *tv) |
| 209 | { |
| 210 | time_t wtm_sec, sec = tv->tv_sec; |
| 211 | long wtm_nsec, nsec = tv->tv_nsec; |
| 212 | |
| 213 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) |
| 214 | return -EINVAL; |
| 215 | |
| 216 | write_seqlock_irq(&xtime_lock); |
| 217 | |
| 218 | /* |
| 219 | * This is revolting. We need to set "xtime" correctly. However, |
| 220 | * the value in this location is the value at the most recent update |
| 221 | * of wall time. Discover what correction gettimeofday() would have |
| 222 | * made, and then undo it! |
| 223 | */ |
| 224 | nsec -= do_gettimeoffset() * NSEC_PER_USEC; |
| 225 | nsec -= (jiffies - wall_jiffies) * tick_nsec; |
| 226 | |
| 227 | wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); |
| 228 | wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); |
| 229 | |
| 230 | set_normalized_timespec(&xtime, sec, nsec); |
| 231 | set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); |
| 232 | |
john stultz | b149ee2 | 2005-09-06 15:17:46 -0700 | [diff] [blame] | 233 | ntp_clear(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 234 | write_sequnlock_irq(&xtime_lock); |
| 235 | clock_was_set(); |
| 236 | return 0; |
| 237 | } |
| 238 | |
| 239 | EXPORT_SYMBOL(do_settimeofday); |
| 240 | |
| 241 | /* |
| 242 | * Gettimeoffset routines. These routines returns the time duration |
| 243 | * since last timer interrupt in usecs. |
| 244 | * |
| 245 | * If the exact CPU counter frequency is known, use fixed_rate_gettimeoffset. |
| 246 | * Otherwise use calibrate_gettimeoffset() |
| 247 | * |
| 248 | * If the CPU does not have the counter register, you can either supply |
| 249 | * your own gettimeoffset() routine, or use null_gettimeoffset(), which |
| 250 | * gives the same resolution as HZ. |
| 251 | */ |
| 252 | |
| 253 | static unsigned long null_gettimeoffset(void) |
| 254 | { |
| 255 | return 0; |
| 256 | } |
| 257 | |
| 258 | |
| 259 | /* The function pointer to one of the gettimeoffset funcs. */ |
| 260 | unsigned long (*do_gettimeoffset)(void) = null_gettimeoffset; |
| 261 | |
| 262 | |
| 263 | static unsigned long fixed_rate_gettimeoffset(void) |
| 264 | { |
| 265 | u32 count; |
| 266 | unsigned long res; |
| 267 | |
| 268 | /* Get last timer tick in absolute kernel time */ |
| 269 | count = mips_hpt_read(); |
| 270 | |
| 271 | /* .. relative to previous jiffy (32 bits is enough) */ |
| 272 | count -= timerlo; |
| 273 | |
| 274 | __asm__("multu %1,%2" |
| 275 | : "=h" (res) |
| 276 | : "r" (count), "r" (sll32_usecs_per_cycle) |
| 277 | : "lo", GCC_REG_ACCUM); |
| 278 | |
| 279 | /* |
| 280 | * Due to possible jiffies inconsistencies, we need to check |
| 281 | * the result so that we'll get a timer that is monotonic. |
| 282 | */ |
| 283 | if (res >= USECS_PER_JIFFY) |
| 284 | res = USECS_PER_JIFFY - 1; |
| 285 | |
| 286 | return res; |
| 287 | } |
| 288 | |
| 289 | |
| 290 | /* |
| 291 | * Cached "1/(clocks per usec) * 2^32" value. |
| 292 | * It has to be recalculated once each jiffy. |
| 293 | */ |
| 294 | static unsigned long cached_quotient; |
| 295 | |
| 296 | /* Last jiffy when calibrate_divXX_gettimeoffset() was called. */ |
| 297 | static unsigned long last_jiffies; |
| 298 | |
| 299 | /* |
| 300 | * This is moved from dec/time.c:do_ioasic_gettimeoffset() by Maciej. |
| 301 | */ |
| 302 | static unsigned long calibrate_div32_gettimeoffset(void) |
| 303 | { |
| 304 | u32 count; |
| 305 | unsigned long res, tmp; |
| 306 | unsigned long quotient; |
| 307 | |
| 308 | tmp = jiffies; |
| 309 | |
| 310 | quotient = cached_quotient; |
| 311 | |
| 312 | if (last_jiffies != tmp) { |
| 313 | last_jiffies = tmp; |
| 314 | if (last_jiffies != 0) { |
| 315 | unsigned long r0; |
| 316 | do_div64_32(r0, timerhi, timerlo, tmp); |
| 317 | do_div64_32(quotient, USECS_PER_JIFFY, |
| 318 | USECS_PER_JIFFY_FRAC, r0); |
| 319 | cached_quotient = quotient; |
| 320 | } |
| 321 | } |
| 322 | |
| 323 | /* Get last timer tick in absolute kernel time */ |
| 324 | count = mips_hpt_read(); |
| 325 | |
| 326 | /* .. relative to previous jiffy (32 bits is enough) */ |
| 327 | count -= timerlo; |
| 328 | |
| 329 | __asm__("multu %1,%2" |
| 330 | : "=h" (res) |
| 331 | : "r" (count), "r" (quotient) |
| 332 | : "lo", GCC_REG_ACCUM); |
| 333 | |
| 334 | /* |
| 335 | * Due to possible jiffies inconsistencies, we need to check |
| 336 | * the result so that we'll get a timer that is monotonic. |
| 337 | */ |
| 338 | if (res >= USECS_PER_JIFFY) |
| 339 | res = USECS_PER_JIFFY - 1; |
| 340 | |
| 341 | return res; |
| 342 | } |
| 343 | |
| 344 | static unsigned long calibrate_div64_gettimeoffset(void) |
| 345 | { |
| 346 | u32 count; |
| 347 | unsigned long res, tmp; |
| 348 | unsigned long quotient; |
| 349 | |
| 350 | tmp = jiffies; |
| 351 | |
| 352 | quotient = cached_quotient; |
| 353 | |
| 354 | if (last_jiffies != tmp) { |
| 355 | last_jiffies = tmp; |
| 356 | if (last_jiffies) { |
| 357 | unsigned long r0; |
| 358 | __asm__(".set push\n\t" |
| 359 | ".set mips3\n\t" |
| 360 | "lwu %0,%3\n\t" |
| 361 | "dsll32 %1,%2,0\n\t" |
| 362 | "or %1,%1,%0\n\t" |
| 363 | "ddivu $0,%1,%4\n\t" |
| 364 | "mflo %1\n\t" |
| 365 | "dsll32 %0,%5,0\n\t" |
| 366 | "or %0,%0,%6\n\t" |
| 367 | "ddivu $0,%0,%1\n\t" |
| 368 | "mflo %0\n\t" |
| 369 | ".set pop" |
| 370 | : "=&r" (quotient), "=&r" (r0) |
| 371 | : "r" (timerhi), "m" (timerlo), |
| 372 | "r" (tmp), "r" (USECS_PER_JIFFY), |
| 373 | "r" (USECS_PER_JIFFY_FRAC) |
| 374 | : "hi", "lo", GCC_REG_ACCUM); |
| 375 | cached_quotient = quotient; |
| 376 | } |
| 377 | } |
| 378 | |
| 379 | /* Get last timer tick in absolute kernel time */ |
| 380 | count = mips_hpt_read(); |
| 381 | |
| 382 | /* .. relative to previous jiffy (32 bits is enough) */ |
| 383 | count -= timerlo; |
| 384 | |
| 385 | __asm__("multu %1,%2" |
| 386 | : "=h" (res) |
| 387 | : "r" (count), "r" (quotient) |
| 388 | : "lo", GCC_REG_ACCUM); |
| 389 | |
| 390 | /* |
| 391 | * Due to possible jiffies inconsistencies, we need to check |
| 392 | * the result so that we'll get a timer that is monotonic. |
| 393 | */ |
| 394 | if (res >= USECS_PER_JIFFY) |
| 395 | res = USECS_PER_JIFFY - 1; |
| 396 | |
| 397 | return res; |
| 398 | } |
| 399 | |
| 400 | |
| 401 | /* last time when xtime and rtc are sync'ed up */ |
| 402 | static long last_rtc_update; |
| 403 | |
| 404 | /* |
| 405 | * local_timer_interrupt() does profiling and process accounting |
| 406 | * on a per-CPU basis. |
| 407 | * |
| 408 | * In UP mode, it is invoked from the (global) timer_interrupt. |
| 409 | * |
| 410 | * In SMP mode, it might invoked by per-CPU timer interrupt, or |
| 411 | * a broadcasted inter-processor interrupt which itself is triggered |
| 412 | * by the global timer interrupt. |
| 413 | */ |
| 414 | void local_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) |
| 415 | { |
| 416 | if (current->pid) |
| 417 | profile_tick(CPU_PROFILING, regs); |
| 418 | update_process_times(user_mode(regs)); |
| 419 | } |
| 420 | |
| 421 | /* |
| 422 | * High-level timer interrupt service routines. This function |
| 423 | * is set as irqaction->handler and is invoked through do_IRQ. |
| 424 | */ |
| 425 | irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) |
| 426 | { |
| 427 | unsigned long j; |
| 428 | unsigned int count; |
| 429 | |
| 430 | count = mips_hpt_read(); |
| 431 | mips_timer_ack(); |
| 432 | |
| 433 | /* Update timerhi/timerlo for intra-jiffy calibration. */ |
| 434 | timerhi += count < timerlo; /* Wrap around */ |
| 435 | timerlo = count; |
| 436 | |
| 437 | /* |
| 438 | * call the generic timer interrupt handling |
| 439 | */ |
| 440 | do_timer(regs); |
| 441 | |
| 442 | /* |
| 443 | * If we have an externally synchronized Linux clock, then update |
| 444 | * CMOS clock accordingly every ~11 minutes. rtc_set_time() has to be |
| 445 | * called as close as possible to 500 ms before the new second starts. |
| 446 | */ |
| 447 | write_seqlock(&xtime_lock); |
john stultz | b149ee2 | 2005-09-06 15:17:46 -0700 | [diff] [blame] | 448 | if (ntp_synced() && |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 449 | xtime.tv_sec > last_rtc_update + 660 && |
| 450 | (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 && |
| 451 | (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) { |
| 452 | if (rtc_set_mmss(xtime.tv_sec) == 0) { |
| 453 | last_rtc_update = xtime.tv_sec; |
| 454 | } else { |
| 455 | /* do it again in 60 s */ |
| 456 | last_rtc_update = xtime.tv_sec - 600; |
| 457 | } |
| 458 | } |
| 459 | write_sequnlock(&xtime_lock); |
| 460 | |
| 461 | /* |
| 462 | * If jiffies has overflown in this timer_interrupt, we must |
| 463 | * update the timer[hi]/[lo] to make fast gettimeoffset funcs |
| 464 | * quotient calc still valid. -arca |
| 465 | * |
| 466 | * The first timer interrupt comes late as interrupts are |
| 467 | * enabled long after timers are initialized. Therefore the |
| 468 | * high precision timer is fast, leading to wrong gettimeoffset() |
| 469 | * calculations. We deal with it by setting it based on the |
| 470 | * number of its ticks between the second and the third interrupt. |
| 471 | * That is still somewhat imprecise, but it's a good estimate. |
| 472 | * --macro |
| 473 | */ |
| 474 | j = jiffies; |
| 475 | if (j < 4) { |
| 476 | static unsigned int prev_count; |
| 477 | static int hpt_initialized; |
| 478 | |
| 479 | switch (j) { |
| 480 | case 0: |
| 481 | timerhi = timerlo = 0; |
| 482 | mips_hpt_init(count); |
| 483 | break; |
| 484 | case 2: |
| 485 | prev_count = count; |
| 486 | break; |
| 487 | case 3: |
| 488 | if (!hpt_initialized) { |
| 489 | unsigned int c3 = 3 * (count - prev_count); |
| 490 | |
| 491 | timerhi = 0; |
| 492 | timerlo = c3; |
| 493 | mips_hpt_init(count - c3); |
| 494 | hpt_initialized = 1; |
| 495 | } |
| 496 | break; |
| 497 | default: |
| 498 | break; |
| 499 | } |
| 500 | } |
| 501 | |
| 502 | /* |
| 503 | * In UP mode, we call local_timer_interrupt() to do profiling |
| 504 | * and process accouting. |
| 505 | * |
| 506 | * In SMP mode, local_timer_interrupt() is invoked by appropriate |
| 507 | * low-level local timer interrupt handler. |
| 508 | */ |
| 509 | local_timer_interrupt(irq, dev_id, regs); |
| 510 | |
| 511 | return IRQ_HANDLED; |
| 512 | } |
| 513 | |
| 514 | asmlinkage void ll_timer_interrupt(int irq, struct pt_regs *regs) |
| 515 | { |
| 516 | irq_enter(); |
| 517 | kstat_this_cpu.irqs[irq]++; |
| 518 | |
| 519 | /* we keep interrupt disabled all the time */ |
| 520 | timer_interrupt(irq, NULL, regs); |
| 521 | |
| 522 | irq_exit(); |
| 523 | } |
| 524 | |
| 525 | asmlinkage void ll_local_timer_interrupt(int irq, struct pt_regs *regs) |
| 526 | { |
| 527 | irq_enter(); |
| 528 | if (smp_processor_id() != 0) |
| 529 | kstat_this_cpu.irqs[irq]++; |
| 530 | |
| 531 | /* we keep interrupt disabled all the time */ |
| 532 | local_timer_interrupt(irq, NULL, regs); |
| 533 | |
| 534 | irq_exit(); |
| 535 | } |
| 536 | |
| 537 | /* |
| 538 | * time_init() - it does the following things. |
| 539 | * |
| 540 | * 1) board_time_init() - |
| 541 | * a) (optional) set up RTC routines, |
| 542 | * b) (optional) calibrate and set the mips_hpt_frequency |
| 543 | * (only needed if you intended to use fixed_rate_gettimeoffset |
| 544 | * or use cpu counter as timer interrupt source) |
| 545 | * 2) setup xtime based on rtc_get_time(). |
| 546 | * 3) choose a appropriate gettimeoffset routine. |
| 547 | * 4) calculate a couple of cached variables for later usage |
| 548 | * 5) board_timer_setup() - |
| 549 | * a) (optional) over-write any choices made above by time_init(). |
| 550 | * b) machine specific code should setup the timer irqaction. |
| 551 | * c) enable the timer interrupt |
| 552 | */ |
| 553 | |
| 554 | void (*board_time_init)(void); |
| 555 | void (*board_timer_setup)(struct irqaction *irq); |
| 556 | |
| 557 | unsigned int mips_hpt_frequency; |
| 558 | |
| 559 | static struct irqaction timer_irqaction = { |
| 560 | .handler = timer_interrupt, |
| 561 | .flags = SA_INTERRUPT, |
| 562 | .name = "timer", |
| 563 | }; |
| 564 | |
| 565 | static unsigned int __init calibrate_hpt(void) |
| 566 | { |
| 567 | u64 frequency; |
| 568 | u32 hpt_start, hpt_end, hpt_count, hz; |
| 569 | |
| 570 | const int loops = HZ / 10; |
| 571 | int log_2_loops = 0; |
| 572 | int i; |
| 573 | |
| 574 | /* |
| 575 | * We want to calibrate for 0.1s, but to avoid a 64-bit |
| 576 | * division we round the number of loops up to the nearest |
| 577 | * power of 2. |
| 578 | */ |
| 579 | while (loops > 1 << log_2_loops) |
| 580 | log_2_loops++; |
| 581 | i = 1 << log_2_loops; |
| 582 | |
| 583 | /* |
| 584 | * Wait for a rising edge of the timer interrupt. |
| 585 | */ |
| 586 | while (mips_timer_state()); |
| 587 | while (!mips_timer_state()); |
| 588 | |
| 589 | /* |
| 590 | * Now see how many high precision timer ticks happen |
| 591 | * during the calculated number of periods between timer |
| 592 | * interrupts. |
| 593 | */ |
| 594 | hpt_start = mips_hpt_read(); |
| 595 | do { |
| 596 | while (mips_timer_state()); |
| 597 | while (!mips_timer_state()); |
| 598 | } while (--i); |
| 599 | hpt_end = mips_hpt_read(); |
| 600 | |
| 601 | hpt_count = hpt_end - hpt_start; |
| 602 | hz = HZ; |
| 603 | frequency = (u64)hpt_count * (u64)hz; |
| 604 | |
| 605 | return frequency >> log_2_loops; |
| 606 | } |
| 607 | |
| 608 | void __init time_init(void) |
| 609 | { |
| 610 | if (board_time_init) |
| 611 | board_time_init(); |
| 612 | |
| 613 | if (!rtc_set_mmss) |
| 614 | rtc_set_mmss = rtc_set_time; |
| 615 | |
| 616 | xtime.tv_sec = rtc_get_time(); |
| 617 | xtime.tv_nsec = 0; |
| 618 | |
| 619 | set_normalized_timespec(&wall_to_monotonic, |
| 620 | -xtime.tv_sec, -xtime.tv_nsec); |
| 621 | |
| 622 | /* Choose appropriate high precision timer routines. */ |
| 623 | if (!cpu_has_counter && !mips_hpt_read) { |
| 624 | /* No high precision timer -- sorry. */ |
| 625 | mips_hpt_read = null_hpt_read; |
| 626 | mips_hpt_init = null_hpt_init; |
| 627 | } else if (!mips_hpt_frequency && !mips_timer_state) { |
| 628 | /* A high precision timer of unknown frequency. */ |
| 629 | if (!mips_hpt_read) { |
| 630 | /* No external high precision timer -- use R4k. */ |
| 631 | mips_hpt_read = c0_hpt_read; |
| 632 | mips_hpt_init = c0_hpt_init; |
| 633 | } |
| 634 | |
| 635 | if ((current_cpu_data.isa_level == MIPS_CPU_ISA_M32) || |
| 636 | (current_cpu_data.isa_level == MIPS_CPU_ISA_I) || |
| 637 | (current_cpu_data.isa_level == MIPS_CPU_ISA_II)) |
| 638 | /* |
| 639 | * We need to calibrate the counter but we don't have |
| 640 | * 64-bit division. |
| 641 | */ |
| 642 | do_gettimeoffset = calibrate_div32_gettimeoffset; |
| 643 | else |
| 644 | /* |
| 645 | * We need to calibrate the counter but we *do* have |
| 646 | * 64-bit division. |
| 647 | */ |
| 648 | do_gettimeoffset = calibrate_div64_gettimeoffset; |
| 649 | } else { |
| 650 | /* We know counter frequency. Or we can get it. */ |
| 651 | if (!mips_hpt_read) { |
| 652 | /* No external high precision timer -- use R4k. */ |
| 653 | mips_hpt_read = c0_hpt_read; |
| 654 | |
| 655 | if (mips_timer_state) |
| 656 | mips_hpt_init = c0_hpt_init; |
| 657 | else { |
| 658 | /* No external timer interrupt -- use R4k. */ |
| 659 | mips_hpt_init = c0_hpt_timer_init; |
| 660 | mips_timer_ack = c0_timer_ack; |
| 661 | } |
| 662 | } |
| 663 | if (!mips_hpt_frequency) |
| 664 | mips_hpt_frequency = calibrate_hpt(); |
| 665 | |
| 666 | do_gettimeoffset = fixed_rate_gettimeoffset; |
| 667 | |
| 668 | /* Calculate cache parameters. */ |
| 669 | cycles_per_jiffy = (mips_hpt_frequency + HZ / 2) / HZ; |
| 670 | |
| 671 | /* sll32_usecs_per_cycle = 10^6 * 2^32 / mips_counter_freq */ |
| 672 | do_div64_32(sll32_usecs_per_cycle, |
| 673 | 1000000, mips_hpt_frequency / 2, |
| 674 | mips_hpt_frequency); |
| 675 | |
| 676 | /* Report the high precision timer rate for a reference. */ |
| 677 | printk("Using %u.%03u MHz high precision timer.\n", |
| 678 | ((mips_hpt_frequency + 500) / 1000) / 1000, |
| 679 | ((mips_hpt_frequency + 500) / 1000) % 1000); |
| 680 | } |
| 681 | |
| 682 | if (!mips_timer_ack) |
| 683 | /* No timer interrupt ack (e.g. i8254). */ |
| 684 | mips_timer_ack = null_timer_ack; |
| 685 | |
| 686 | /* This sets up the high precision timer for the first interrupt. */ |
| 687 | mips_hpt_init(mips_hpt_read()); |
| 688 | |
| 689 | /* |
| 690 | * Call board specific timer interrupt setup. |
| 691 | * |
| 692 | * this pointer must be setup in machine setup routine. |
| 693 | * |
| 694 | * Even if a machine chooses to use a low-level timer interrupt, |
| 695 | * it still needs to setup the timer_irqaction. |
| 696 | * In that case, it might be better to set timer_irqaction.handler |
| 697 | * to be NULL function so that we are sure the high-level code |
| 698 | * is not invoked accidentally. |
| 699 | */ |
| 700 | board_timer_setup(&timer_irqaction); |
| 701 | } |
| 702 | |
| 703 | #define FEBRUARY 2 |
| 704 | #define STARTOFTIME 1970 |
| 705 | #define SECDAY 86400L |
| 706 | #define SECYR (SECDAY * 365) |
| 707 | #define leapyear(y) ((!((y) % 4) && ((y) % 100)) || !((y) % 400)) |
| 708 | #define days_in_year(y) (leapyear(y) ? 366 : 365) |
| 709 | #define days_in_month(m) (month_days[(m) - 1]) |
| 710 | |
| 711 | static int month_days[12] = { |
| 712 | 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 |
| 713 | }; |
| 714 | |
| 715 | void to_tm(unsigned long tim, struct rtc_time *tm) |
| 716 | { |
| 717 | long hms, day, gday; |
| 718 | int i; |
| 719 | |
| 720 | gday = day = tim / SECDAY; |
| 721 | hms = tim % SECDAY; |
| 722 | |
| 723 | /* Hours, minutes, seconds are easy */ |
| 724 | tm->tm_hour = hms / 3600; |
| 725 | tm->tm_min = (hms % 3600) / 60; |
| 726 | tm->tm_sec = (hms % 3600) % 60; |
| 727 | |
| 728 | /* Number of years in days */ |
| 729 | for (i = STARTOFTIME; day >= days_in_year(i); i++) |
| 730 | day -= days_in_year(i); |
| 731 | tm->tm_year = i; |
| 732 | |
| 733 | /* Number of months in days left */ |
| 734 | if (leapyear(tm->tm_year)) |
| 735 | days_in_month(FEBRUARY) = 29; |
| 736 | for (i = 1; day >= days_in_month(i); i++) |
| 737 | day -= days_in_month(i); |
| 738 | days_in_month(FEBRUARY) = 28; |
| 739 | tm->tm_mon = i - 1; /* tm_mon starts from 0 to 11 */ |
| 740 | |
| 741 | /* Days are what is left over (+1) from all that. */ |
| 742 | tm->tm_mday = day + 1; |
| 743 | |
| 744 | /* |
| 745 | * Determine the day of week |
| 746 | */ |
| 747 | tm->tm_wday = (gday + 4) % 7; /* 1970/1/1 was Thursday */ |
| 748 | } |
| 749 | |
| 750 | EXPORT_SYMBOL(rtc_lock); |
| 751 | EXPORT_SYMBOL(to_tm); |
| 752 | EXPORT_SYMBOL(rtc_set_time); |
| 753 | EXPORT_SYMBOL(rtc_get_time); |
| 754 | |
| 755 | unsigned long long sched_clock(void) |
| 756 | { |
| 757 | return (unsigned long long)jiffies*(1000000000/HZ); |
| 758 | } |