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1da177e4 LT |
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 | */ | |
bdf21b18 | 14 | #include <linux/config.h> |
1da177e4 LT |
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> | |
ec74e361 | 29 | #include <asm/cache.h> |
1da177e4 LT |
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 | ||
1da177e4 LT |
48 | /* |
49 | * forward reference | |
50 | */ | |
51 | extern volatile unsigned long wall_jiffies; | |
52 | ||
53 | DEFINE_SPINLOCK(rtc_lock); | |
54 | ||
55 | /* | |
56 | * By default we provide the null RTC ops | |
57 | */ | |
58 | static unsigned long null_rtc_get_time(void) | |
59 | { | |
60 | return mktime(2000, 1, 1, 0, 0, 0); | |
61 | } | |
62 | ||
63 | static int null_rtc_set_time(unsigned long sec) | |
64 | { | |
65 | return 0; | |
66 | } | |
67 | ||
d23ee8fe YY |
68 | unsigned long (*rtc_mips_get_time)(void) = null_rtc_get_time; |
69 | int (*rtc_mips_set_time)(unsigned long) = null_rtc_set_time; | |
70 | int (*rtc_mips_set_mmss)(unsigned long); | |
1da177e4 LT |
71 | |
72 | ||
73 | /* usecs per counter cycle, shifted to left by 32 bits */ | |
74 | static unsigned int sll32_usecs_per_cycle; | |
75 | ||
76 | /* how many counter cycles in a jiffy */ | |
ec74e361 | 77 | static unsigned long cycles_per_jiffy __read_mostly; |
1da177e4 LT |
78 | |
79 | /* Cycle counter value at the previous timer interrupt.. */ | |
80 | static unsigned int timerhi, timerlo; | |
81 | ||
82 | /* expirelo is the count value for next CPU timer interrupt */ | |
83 | static unsigned int expirelo; | |
84 | ||
85 | ||
86 | /* | |
87 | * Null timer ack for systems not needing one (e.g. i8254). | |
88 | */ | |
89 | static void null_timer_ack(void) { /* nothing */ } | |
90 | ||
91 | /* | |
92 | * Null high precision timer functions for systems lacking one. | |
93 | */ | |
94 | static unsigned int null_hpt_read(void) | |
95 | { | |
96 | return 0; | |
97 | } | |
98 | ||
ec74e361 RB |
99 | static void null_hpt_init(unsigned int count) |
100 | { | |
101 | /* nothing */ | |
102 | } | |
1da177e4 LT |
103 | |
104 | ||
105 | /* | |
106 | * Timer ack for an R4k-compatible timer of a known frequency. | |
107 | */ | |
108 | static void c0_timer_ack(void) | |
109 | { | |
110 | unsigned int count; | |
111 | ||
bdf21b18 | 112 | #ifndef CONFIG_SOC_PNX8550 /* pnx8550 resets to zero */ |
1da177e4 LT |
113 | /* Ack this timer interrupt and set the next one. */ |
114 | expirelo += cycles_per_jiffy; | |
bdf21b18 | 115 | #endif |
1da177e4 LT |
116 | write_c0_compare(expirelo); |
117 | ||
118 | /* Check to see if we have missed any timer interrupts. */ | |
41c594ab | 119 | while (((count = read_c0_count()) - expirelo) < 0x7fffffff) { |
1da177e4 LT |
120 | /* missed_timer_count++; */ |
121 | expirelo = count + cycles_per_jiffy; | |
122 | write_c0_compare(expirelo); | |
123 | } | |
124 | } | |
125 | ||
126 | /* | |
127 | * High precision timer functions for a R4k-compatible timer. | |
128 | */ | |
129 | static unsigned int c0_hpt_read(void) | |
130 | { | |
131 | return read_c0_count(); | |
132 | } | |
133 | ||
134 | /* For use solely as a high precision timer. */ | |
135 | static void c0_hpt_init(unsigned int count) | |
136 | { | |
137 | write_c0_count(read_c0_count() - count); | |
138 | } | |
139 | ||
140 | /* For use both as a high precision timer and an interrupt source. */ | |
141 | static void c0_hpt_timer_init(unsigned int count) | |
142 | { | |
143 | count = read_c0_count() - count; | |
144 | expirelo = (count / cycles_per_jiffy + 1) * cycles_per_jiffy; | |
145 | write_c0_count(expirelo - cycles_per_jiffy); | |
146 | write_c0_compare(expirelo); | |
147 | write_c0_count(count); | |
148 | } | |
149 | ||
150 | int (*mips_timer_state)(void); | |
151 | void (*mips_timer_ack)(void); | |
152 | unsigned int (*mips_hpt_read)(void); | |
153 | void (*mips_hpt_init)(unsigned int); | |
154 | ||
155 | ||
156 | /* | |
157 | * This version of gettimeofday has microsecond resolution and better than | |
158 | * microsecond precision on fast machines with cycle counter. | |
159 | */ | |
160 | void do_gettimeofday(struct timeval *tv) | |
161 | { | |
162 | unsigned long seq; | |
163 | unsigned long lost; | |
164 | unsigned long usec, sec; | |
800d1142 | 165 | unsigned long max_ntp_tick; |
1da177e4 LT |
166 | |
167 | do { | |
168 | seq = read_seqbegin(&xtime_lock); | |
169 | ||
170 | usec = do_gettimeoffset(); | |
171 | ||
172 | lost = jiffies - wall_jiffies; | |
173 | ||
174 | /* | |
175 | * If time_adjust is negative then NTP is slowing the clock | |
176 | * so make sure not to go into next possible interval. | |
177 | * Better to lose some accuracy than have time go backwards.. | |
178 | */ | |
179 | if (unlikely(time_adjust < 0)) { | |
800d1142 | 180 | max_ntp_tick = (USEC_PER_SEC / HZ) - tickadj; |
1da177e4 LT |
181 | usec = min(usec, max_ntp_tick); |
182 | ||
183 | if (lost) | |
184 | usec += lost * max_ntp_tick; | |
185 | } else if (unlikely(lost)) | |
800d1142 | 186 | usec += lost * (USEC_PER_SEC / HZ); |
1da177e4 LT |
187 | |
188 | sec = xtime.tv_sec; | |
189 | usec += (xtime.tv_nsec / 1000); | |
190 | ||
191 | } while (read_seqretry(&xtime_lock, seq)); | |
192 | ||
193 | while (usec >= 1000000) { | |
194 | usec -= 1000000; | |
195 | sec++; | |
196 | } | |
197 | ||
198 | tv->tv_sec = sec; | |
199 | tv->tv_usec = usec; | |
200 | } | |
201 | ||
202 | EXPORT_SYMBOL(do_gettimeofday); | |
203 | ||
204 | int do_settimeofday(struct timespec *tv) | |
205 | { | |
206 | time_t wtm_sec, sec = tv->tv_sec; | |
207 | long wtm_nsec, nsec = tv->tv_nsec; | |
208 | ||
209 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
210 | return -EINVAL; | |
211 | ||
212 | write_seqlock_irq(&xtime_lock); | |
213 | ||
214 | /* | |
215 | * This is revolting. We need to set "xtime" correctly. However, | |
216 | * the value in this location is the value at the most recent update | |
217 | * of wall time. Discover what correction gettimeofday() would have | |
218 | * made, and then undo it! | |
219 | */ | |
220 | nsec -= do_gettimeoffset() * NSEC_PER_USEC; | |
221 | nsec -= (jiffies - wall_jiffies) * tick_nsec; | |
222 | ||
223 | wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); | |
224 | wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); | |
225 | ||
226 | set_normalized_timespec(&xtime, sec, nsec); | |
227 | set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); | |
228 | ||
b149ee22 | 229 | ntp_clear(); |
1da177e4 LT |
230 | write_sequnlock_irq(&xtime_lock); |
231 | clock_was_set(); | |
232 | return 0; | |
233 | } | |
234 | ||
235 | EXPORT_SYMBOL(do_settimeofday); | |
236 | ||
237 | /* | |
238 | * Gettimeoffset routines. These routines returns the time duration | |
239 | * since last timer interrupt in usecs. | |
240 | * | |
241 | * If the exact CPU counter frequency is known, use fixed_rate_gettimeoffset. | |
242 | * Otherwise use calibrate_gettimeoffset() | |
243 | * | |
244 | * If the CPU does not have the counter register, you can either supply | |
245 | * your own gettimeoffset() routine, or use null_gettimeoffset(), which | |
246 | * gives the same resolution as HZ. | |
247 | */ | |
248 | ||
249 | static unsigned long null_gettimeoffset(void) | |
250 | { | |
251 | return 0; | |
252 | } | |
253 | ||
254 | ||
255 | /* The function pointer to one of the gettimeoffset funcs. */ | |
256 | unsigned long (*do_gettimeoffset)(void) = null_gettimeoffset; | |
257 | ||
258 | ||
259 | static unsigned long fixed_rate_gettimeoffset(void) | |
260 | { | |
261 | u32 count; | |
262 | unsigned long res; | |
263 | ||
264 | /* Get last timer tick in absolute kernel time */ | |
265 | count = mips_hpt_read(); | |
266 | ||
267 | /* .. relative to previous jiffy (32 bits is enough) */ | |
268 | count -= timerlo; | |
269 | ||
270 | __asm__("multu %1,%2" | |
271 | : "=h" (res) | |
272 | : "r" (count), "r" (sll32_usecs_per_cycle) | |
273 | : "lo", GCC_REG_ACCUM); | |
274 | ||
275 | /* | |
276 | * Due to possible jiffies inconsistencies, we need to check | |
277 | * the result so that we'll get a timer that is monotonic. | |
278 | */ | |
279 | if (res >= USECS_PER_JIFFY) | |
280 | res = USECS_PER_JIFFY - 1; | |
281 | ||
282 | return res; | |
283 | } | |
284 | ||
285 | ||
286 | /* | |
287 | * Cached "1/(clocks per usec) * 2^32" value. | |
288 | * It has to be recalculated once each jiffy. | |
289 | */ | |
290 | static unsigned long cached_quotient; | |
291 | ||
292 | /* Last jiffy when calibrate_divXX_gettimeoffset() was called. */ | |
293 | static unsigned long last_jiffies; | |
294 | ||
295 | /* | |
296 | * This is moved from dec/time.c:do_ioasic_gettimeoffset() by Maciej. | |
297 | */ | |
298 | static unsigned long calibrate_div32_gettimeoffset(void) | |
299 | { | |
300 | u32 count; | |
301 | unsigned long res, tmp; | |
302 | unsigned long quotient; | |
303 | ||
304 | tmp = jiffies; | |
305 | ||
306 | quotient = cached_quotient; | |
307 | ||
308 | if (last_jiffies != tmp) { | |
309 | last_jiffies = tmp; | |
310 | if (last_jiffies != 0) { | |
311 | unsigned long r0; | |
312 | do_div64_32(r0, timerhi, timerlo, tmp); | |
313 | do_div64_32(quotient, USECS_PER_JIFFY, | |
314 | USECS_PER_JIFFY_FRAC, r0); | |
315 | cached_quotient = quotient; | |
316 | } | |
317 | } | |
318 | ||
319 | /* Get last timer tick in absolute kernel time */ | |
320 | count = mips_hpt_read(); | |
321 | ||
322 | /* .. relative to previous jiffy (32 bits is enough) */ | |
323 | count -= timerlo; | |
324 | ||
325 | __asm__("multu %1,%2" | |
326 | : "=h" (res) | |
327 | : "r" (count), "r" (quotient) | |
328 | : "lo", GCC_REG_ACCUM); | |
329 | ||
330 | /* | |
331 | * Due to possible jiffies inconsistencies, we need to check | |
332 | * the result so that we'll get a timer that is monotonic. | |
333 | */ | |
334 | if (res >= USECS_PER_JIFFY) | |
335 | res = USECS_PER_JIFFY - 1; | |
336 | ||
337 | return res; | |
338 | } | |
339 | ||
340 | static unsigned long calibrate_div64_gettimeoffset(void) | |
341 | { | |
342 | u32 count; | |
343 | unsigned long res, tmp; | |
344 | unsigned long quotient; | |
345 | ||
346 | tmp = jiffies; | |
347 | ||
348 | quotient = cached_quotient; | |
349 | ||
350 | if (last_jiffies != tmp) { | |
351 | last_jiffies = tmp; | |
352 | if (last_jiffies) { | |
353 | unsigned long r0; | |
354 | __asm__(".set push\n\t" | |
355 | ".set mips3\n\t" | |
356 | "lwu %0,%3\n\t" | |
357 | "dsll32 %1,%2,0\n\t" | |
358 | "or %1,%1,%0\n\t" | |
359 | "ddivu $0,%1,%4\n\t" | |
360 | "mflo %1\n\t" | |
361 | "dsll32 %0,%5,0\n\t" | |
362 | "or %0,%0,%6\n\t" | |
363 | "ddivu $0,%0,%1\n\t" | |
364 | "mflo %0\n\t" | |
365 | ".set pop" | |
366 | : "=&r" (quotient), "=&r" (r0) | |
367 | : "r" (timerhi), "m" (timerlo), | |
368 | "r" (tmp), "r" (USECS_PER_JIFFY), | |
369 | "r" (USECS_PER_JIFFY_FRAC) | |
370 | : "hi", "lo", GCC_REG_ACCUM); | |
371 | cached_quotient = quotient; | |
372 | } | |
373 | } | |
374 | ||
375 | /* Get last timer tick in absolute kernel time */ | |
376 | count = mips_hpt_read(); | |
377 | ||
378 | /* .. relative to previous jiffy (32 bits is enough) */ | |
379 | count -= timerlo; | |
380 | ||
381 | __asm__("multu %1,%2" | |
382 | : "=h" (res) | |
383 | : "r" (count), "r" (quotient) | |
384 | : "lo", GCC_REG_ACCUM); | |
385 | ||
386 | /* | |
387 | * Due to possible jiffies inconsistencies, we need to check | |
388 | * the result so that we'll get a timer that is monotonic. | |
389 | */ | |
390 | if (res >= USECS_PER_JIFFY) | |
391 | res = USECS_PER_JIFFY - 1; | |
392 | ||
393 | return res; | |
394 | } | |
395 | ||
396 | ||
397 | /* last time when xtime and rtc are sync'ed up */ | |
398 | static long last_rtc_update; | |
399 | ||
400 | /* | |
401 | * local_timer_interrupt() does profiling and process accounting | |
402 | * on a per-CPU basis. | |
403 | * | |
404 | * In UP mode, it is invoked from the (global) timer_interrupt. | |
405 | * | |
406 | * In SMP mode, it might invoked by per-CPU timer interrupt, or | |
407 | * a broadcasted inter-processor interrupt which itself is triggered | |
408 | * by the global timer interrupt. | |
409 | */ | |
410 | void local_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) | |
411 | { | |
412 | if (current->pid) | |
413 | profile_tick(CPU_PROFILING, regs); | |
414 | update_process_times(user_mode(regs)); | |
415 | } | |
416 | ||
417 | /* | |
418 | * High-level timer interrupt service routines. This function | |
419 | * is set as irqaction->handler and is invoked through do_IRQ. | |
420 | */ | |
421 | irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) | |
422 | { | |
423 | unsigned long j; | |
424 | unsigned int count; | |
425 | ||
d6bd0e6b RB |
426 | write_seqlock(&xtime_lock); |
427 | ||
1da177e4 LT |
428 | count = mips_hpt_read(); |
429 | mips_timer_ack(); | |
430 | ||
431 | /* Update timerhi/timerlo for intra-jiffy calibration. */ | |
432 | timerhi += count < timerlo; /* Wrap around */ | |
433 | timerlo = count; | |
434 | ||
435 | /* | |
436 | * call the generic timer interrupt handling | |
437 | */ | |
438 | do_timer(regs); | |
439 | ||
440 | /* | |
441 | * If we have an externally synchronized Linux clock, then update | |
d23ee8fe | 442 | * CMOS clock accordingly every ~11 minutes. rtc_mips_set_time() has to be |
1da177e4 LT |
443 | * called as close as possible to 500 ms before the new second starts. |
444 | */ | |
b149ee22 | 445 | if (ntp_synced() && |
1da177e4 LT |
446 | xtime.tv_sec > last_rtc_update + 660 && |
447 | (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 && | |
448 | (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) { | |
d23ee8fe | 449 | if (rtc_mips_set_mmss(xtime.tv_sec) == 0) { |
1da177e4 LT |
450 | last_rtc_update = xtime.tv_sec; |
451 | } else { | |
452 | /* do it again in 60 s */ | |
453 | last_rtc_update = xtime.tv_sec - 600; | |
454 | } | |
455 | } | |
1da177e4 LT |
456 | |
457 | /* | |
458 | * If jiffies has overflown in this timer_interrupt, we must | |
459 | * update the timer[hi]/[lo] to make fast gettimeoffset funcs | |
460 | * quotient calc still valid. -arca | |
461 | * | |
462 | * The first timer interrupt comes late as interrupts are | |
463 | * enabled long after timers are initialized. Therefore the | |
464 | * high precision timer is fast, leading to wrong gettimeoffset() | |
465 | * calculations. We deal with it by setting it based on the | |
466 | * number of its ticks between the second and the third interrupt. | |
467 | * That is still somewhat imprecise, but it's a good estimate. | |
468 | * --macro | |
469 | */ | |
470 | j = jiffies; | |
471 | if (j < 4) { | |
472 | static unsigned int prev_count; | |
473 | static int hpt_initialized; | |
474 | ||
475 | switch (j) { | |
476 | case 0: | |
477 | timerhi = timerlo = 0; | |
478 | mips_hpt_init(count); | |
479 | break; | |
480 | case 2: | |
481 | prev_count = count; | |
482 | break; | |
483 | case 3: | |
484 | if (!hpt_initialized) { | |
485 | unsigned int c3 = 3 * (count - prev_count); | |
486 | ||
487 | timerhi = 0; | |
488 | timerlo = c3; | |
489 | mips_hpt_init(count - c3); | |
490 | hpt_initialized = 1; | |
491 | } | |
492 | break; | |
493 | default: | |
494 | break; | |
495 | } | |
496 | } | |
497 | ||
d6bd0e6b RB |
498 | write_sequnlock(&xtime_lock); |
499 | ||
1da177e4 LT |
500 | /* |
501 | * In UP mode, we call local_timer_interrupt() to do profiling | |
502 | * and process accouting. | |
503 | * | |
504 | * In SMP mode, local_timer_interrupt() is invoked by appropriate | |
505 | * low-level local timer interrupt handler. | |
506 | */ | |
507 | local_timer_interrupt(irq, dev_id, regs); | |
508 | ||
509 | return IRQ_HANDLED; | |
510 | } | |
511 | ||
ba339c03 RB |
512 | int null_perf_irq(struct pt_regs *regs) |
513 | { | |
514 | return 0; | |
515 | } | |
516 | ||
517 | int (*perf_irq)(struct pt_regs *regs) = null_perf_irq; | |
518 | ||
519 | EXPORT_SYMBOL(null_perf_irq); | |
520 | EXPORT_SYMBOL(perf_irq); | |
521 | ||
1da177e4 LT |
522 | asmlinkage void ll_timer_interrupt(int irq, struct pt_regs *regs) |
523 | { | |
ba339c03 RB |
524 | int r2 = cpu_has_mips_r2; |
525 | ||
1da177e4 LT |
526 | irq_enter(); |
527 | kstat_this_cpu.irqs[irq]++; | |
528 | ||
ba339c03 RB |
529 | /* |
530 | * Suckage alert: | |
531 | * Before R2 of the architecture there was no way to see if a | |
532 | * performance counter interrupt was pending, so we have to run the | |
533 | * performance counter interrupt handler anyway. | |
534 | */ | |
535 | if (!r2 || (read_c0_cause() & (1 << 26))) | |
536 | if (perf_irq(regs)) | |
537 | goto out; | |
538 | ||
1da177e4 | 539 | /* we keep interrupt disabled all the time */ |
ba339c03 RB |
540 | if (!r2 || (read_c0_cause() & (1 << 30))) |
541 | timer_interrupt(irq, NULL, regs); | |
1da177e4 | 542 | |
ba339c03 | 543 | out: |
1da177e4 LT |
544 | irq_exit(); |
545 | } | |
546 | ||
547 | asmlinkage void ll_local_timer_interrupt(int irq, struct pt_regs *regs) | |
548 | { | |
549 | irq_enter(); | |
550 | if (smp_processor_id() != 0) | |
551 | kstat_this_cpu.irqs[irq]++; | |
552 | ||
553 | /* we keep interrupt disabled all the time */ | |
554 | local_timer_interrupt(irq, NULL, regs); | |
555 | ||
556 | irq_exit(); | |
557 | } | |
558 | ||
559 | /* | |
560 | * time_init() - it does the following things. | |
561 | * | |
562 | * 1) board_time_init() - | |
563 | * a) (optional) set up RTC routines, | |
564 | * b) (optional) calibrate and set the mips_hpt_frequency | |
565 | * (only needed if you intended to use fixed_rate_gettimeoffset | |
566 | * or use cpu counter as timer interrupt source) | |
d23ee8fe | 567 | * 2) setup xtime based on rtc_mips_get_time(). |
1da177e4 LT |
568 | * 3) choose a appropriate gettimeoffset routine. |
569 | * 4) calculate a couple of cached variables for later usage | |
570 | * 5) board_timer_setup() - | |
571 | * a) (optional) over-write any choices made above by time_init(). | |
572 | * b) machine specific code should setup the timer irqaction. | |
573 | * c) enable the timer interrupt | |
574 | */ | |
575 | ||
576 | void (*board_time_init)(void); | |
577 | void (*board_timer_setup)(struct irqaction *irq); | |
578 | ||
579 | unsigned int mips_hpt_frequency; | |
580 | ||
581 | static struct irqaction timer_irqaction = { | |
582 | .handler = timer_interrupt, | |
583 | .flags = SA_INTERRUPT, | |
584 | .name = "timer", | |
585 | }; | |
586 | ||
587 | static unsigned int __init calibrate_hpt(void) | |
588 | { | |
589 | u64 frequency; | |
590 | u32 hpt_start, hpt_end, hpt_count, hz; | |
591 | ||
592 | const int loops = HZ / 10; | |
593 | int log_2_loops = 0; | |
594 | int i; | |
595 | ||
596 | /* | |
597 | * We want to calibrate for 0.1s, but to avoid a 64-bit | |
598 | * division we round the number of loops up to the nearest | |
599 | * power of 2. | |
600 | */ | |
601 | while (loops > 1 << log_2_loops) | |
602 | log_2_loops++; | |
603 | i = 1 << log_2_loops; | |
604 | ||
605 | /* | |
606 | * Wait for a rising edge of the timer interrupt. | |
607 | */ | |
608 | while (mips_timer_state()); | |
609 | while (!mips_timer_state()); | |
610 | ||
611 | /* | |
612 | * Now see how many high precision timer ticks happen | |
613 | * during the calculated number of periods between timer | |
614 | * interrupts. | |
615 | */ | |
616 | hpt_start = mips_hpt_read(); | |
617 | do { | |
618 | while (mips_timer_state()); | |
619 | while (!mips_timer_state()); | |
620 | } while (--i); | |
621 | hpt_end = mips_hpt_read(); | |
622 | ||
623 | hpt_count = hpt_end - hpt_start; | |
624 | hz = HZ; | |
625 | frequency = (u64)hpt_count * (u64)hz; | |
626 | ||
627 | return frequency >> log_2_loops; | |
628 | } | |
629 | ||
630 | void __init time_init(void) | |
631 | { | |
632 | if (board_time_init) | |
633 | board_time_init(); | |
634 | ||
d23ee8fe YY |
635 | if (!rtc_mips_set_mmss) |
636 | rtc_mips_set_mmss = rtc_mips_set_time; | |
1da177e4 | 637 | |
d23ee8fe | 638 | xtime.tv_sec = rtc_mips_get_time(); |
1da177e4 LT |
639 | xtime.tv_nsec = 0; |
640 | ||
641 | set_normalized_timespec(&wall_to_monotonic, | |
642 | -xtime.tv_sec, -xtime.tv_nsec); | |
643 | ||
644 | /* Choose appropriate high precision timer routines. */ | |
645 | if (!cpu_has_counter && !mips_hpt_read) { | |
646 | /* No high precision timer -- sorry. */ | |
647 | mips_hpt_read = null_hpt_read; | |
648 | mips_hpt_init = null_hpt_init; | |
649 | } else if (!mips_hpt_frequency && !mips_timer_state) { | |
650 | /* A high precision timer of unknown frequency. */ | |
651 | if (!mips_hpt_read) { | |
652 | /* No external high precision timer -- use R4k. */ | |
653 | mips_hpt_read = c0_hpt_read; | |
654 | mips_hpt_init = c0_hpt_init; | |
655 | } | |
656 | ||
b4672d37 RB |
657 | if (cpu_has_mips32r1 || cpu_has_mips32r2 || |
658 | (current_cpu_data.isa_level == MIPS_CPU_ISA_I) || | |
659 | (current_cpu_data.isa_level == MIPS_CPU_ISA_II)) | |
1da177e4 LT |
660 | /* |
661 | * We need to calibrate the counter but we don't have | |
662 | * 64-bit division. | |
663 | */ | |
664 | do_gettimeoffset = calibrate_div32_gettimeoffset; | |
665 | else | |
666 | /* | |
667 | * We need to calibrate the counter but we *do* have | |
668 | * 64-bit division. | |
669 | */ | |
670 | do_gettimeoffset = calibrate_div64_gettimeoffset; | |
671 | } else { | |
672 | /* We know counter frequency. Or we can get it. */ | |
673 | if (!mips_hpt_read) { | |
674 | /* No external high precision timer -- use R4k. */ | |
675 | mips_hpt_read = c0_hpt_read; | |
676 | ||
677 | if (mips_timer_state) | |
678 | mips_hpt_init = c0_hpt_init; | |
679 | else { | |
680 | /* No external timer interrupt -- use R4k. */ | |
681 | mips_hpt_init = c0_hpt_timer_init; | |
682 | mips_timer_ack = c0_timer_ack; | |
683 | } | |
684 | } | |
685 | if (!mips_hpt_frequency) | |
686 | mips_hpt_frequency = calibrate_hpt(); | |
687 | ||
688 | do_gettimeoffset = fixed_rate_gettimeoffset; | |
689 | ||
690 | /* Calculate cache parameters. */ | |
691 | cycles_per_jiffy = (mips_hpt_frequency + HZ / 2) / HZ; | |
692 | ||
693 | /* sll32_usecs_per_cycle = 10^6 * 2^32 / mips_counter_freq */ | |
694 | do_div64_32(sll32_usecs_per_cycle, | |
695 | 1000000, mips_hpt_frequency / 2, | |
696 | mips_hpt_frequency); | |
697 | ||
698 | /* Report the high precision timer rate for a reference. */ | |
699 | printk("Using %u.%03u MHz high precision timer.\n", | |
700 | ((mips_hpt_frequency + 500) / 1000) / 1000, | |
701 | ((mips_hpt_frequency + 500) / 1000) % 1000); | |
702 | } | |
703 | ||
704 | if (!mips_timer_ack) | |
705 | /* No timer interrupt ack (e.g. i8254). */ | |
706 | mips_timer_ack = null_timer_ack; | |
707 | ||
708 | /* This sets up the high precision timer for the first interrupt. */ | |
709 | mips_hpt_init(mips_hpt_read()); | |
710 | ||
711 | /* | |
712 | * Call board specific timer interrupt setup. | |
713 | * | |
714 | * this pointer must be setup in machine setup routine. | |
715 | * | |
716 | * Even if a machine chooses to use a low-level timer interrupt, | |
717 | * it still needs to setup the timer_irqaction. | |
718 | * In that case, it might be better to set timer_irqaction.handler | |
719 | * to be NULL function so that we are sure the high-level code | |
720 | * is not invoked accidentally. | |
721 | */ | |
722 | board_timer_setup(&timer_irqaction); | |
723 | } | |
724 | ||
725 | #define FEBRUARY 2 | |
726 | #define STARTOFTIME 1970 | |
727 | #define SECDAY 86400L | |
728 | #define SECYR (SECDAY * 365) | |
729 | #define leapyear(y) ((!((y) % 4) && ((y) % 100)) || !((y) % 400)) | |
730 | #define days_in_year(y) (leapyear(y) ? 366 : 365) | |
731 | #define days_in_month(m) (month_days[(m) - 1]) | |
732 | ||
733 | static int month_days[12] = { | |
734 | 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 | |
735 | }; | |
736 | ||
737 | void to_tm(unsigned long tim, struct rtc_time *tm) | |
738 | { | |
739 | long hms, day, gday; | |
740 | int i; | |
741 | ||
742 | gday = day = tim / SECDAY; | |
743 | hms = tim % SECDAY; | |
744 | ||
745 | /* Hours, minutes, seconds are easy */ | |
746 | tm->tm_hour = hms / 3600; | |
747 | tm->tm_min = (hms % 3600) / 60; | |
748 | tm->tm_sec = (hms % 3600) % 60; | |
749 | ||
750 | /* Number of years in days */ | |
751 | for (i = STARTOFTIME; day >= days_in_year(i); i++) | |
752 | day -= days_in_year(i); | |
753 | tm->tm_year = i; | |
754 | ||
755 | /* Number of months in days left */ | |
756 | if (leapyear(tm->tm_year)) | |
757 | days_in_month(FEBRUARY) = 29; | |
758 | for (i = 1; day >= days_in_month(i); i++) | |
759 | day -= days_in_month(i); | |
760 | days_in_month(FEBRUARY) = 28; | |
761 | tm->tm_mon = i - 1; /* tm_mon starts from 0 to 11 */ | |
762 | ||
763 | /* Days are what is left over (+1) from all that. */ | |
764 | tm->tm_mday = day + 1; | |
765 | ||
766 | /* | |
767 | * Determine the day of week | |
768 | */ | |
769 | tm->tm_wday = (gday + 4) % 7; /* 1970/1/1 was Thursday */ | |
770 | } | |
771 | ||
772 | EXPORT_SYMBOL(rtc_lock); | |
773 | EXPORT_SYMBOL(to_tm); | |
d23ee8fe YY |
774 | EXPORT_SYMBOL(rtc_mips_set_time); |
775 | EXPORT_SYMBOL(rtc_mips_get_time); | |
1da177e4 LT |
776 | |
777 | unsigned long long sched_clock(void) | |
778 | { | |
779 | return (unsigned long long)jiffies*(1000000000/HZ); | |
780 | } |