diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/mips/kernel/time.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/mips/kernel/time.c')
-rw-r--r-- | arch/mips/kernel/time.c | 755 |
1 files changed, 755 insertions, 0 deletions
diff --git a/arch/mips/kernel/time.c b/arch/mips/kernel/time.c new file mode 100644 index 000000000000..648c82292ed6 --- /dev/null +++ b/arch/mips/kernel/time.c | |||
@@ -0,0 +1,755 @@ | |||
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 | */ | ||
14 | #include <linux/types.h> | ||
15 | #include <linux/kernel.h> | ||
16 | #include <linux/init.h> | ||
17 | #include <linux/sched.h> | ||
18 | #include <linux/param.h> | ||
19 | #include <linux/time.h> | ||
20 | #include <linux/timex.h> | ||
21 | #include <linux/smp.h> | ||
22 | #include <linux/kernel_stat.h> | ||
23 | #include <linux/spinlock.h> | ||
24 | #include <linux/interrupt.h> | ||
25 | #include <linux/module.h> | ||
26 | |||
27 | #include <asm/bootinfo.h> | ||
28 | #include <asm/compiler.h> | ||
29 | #include <asm/cpu.h> | ||
30 | #include <asm/cpu-features.h> | ||
31 | #include <asm/div64.h> | ||
32 | #include <asm/sections.h> | ||
33 | #include <asm/time.h> | ||
34 | |||
35 | /* | ||
36 | * The integer part of the number of usecs per jiffy is taken from tick, | ||
37 | * but the fractional part is not recorded, so we calculate it using the | ||
38 | * initial value of HZ. This aids systems where tick isn't really an | ||
39 | * integer (e.g. for HZ = 128). | ||
40 | */ | ||
41 | #define USECS_PER_JIFFY TICK_SIZE | ||
42 | #define USECS_PER_JIFFY_FRAC ((unsigned long)(u32)((1000000ULL << 32) / HZ)) | ||
43 | |||
44 | #define TICK_SIZE (tick_nsec / 1000) | ||
45 | |||
46 | u64 jiffies_64 = INITIAL_JIFFIES; | ||
47 | |||
48 | EXPORT_SYMBOL(jiffies_64); | ||
49 | |||
50 | /* | ||
51 | * forward reference | ||
52 | */ | ||
53 | extern volatile unsigned long wall_jiffies; | ||
54 | |||
55 | DEFINE_SPINLOCK(rtc_lock); | ||
56 | |||
57 | /* | ||
58 | * By default we provide the null RTC ops | ||
59 | */ | ||
60 | static unsigned long null_rtc_get_time(void) | ||
61 | { | ||
62 | return mktime(2000, 1, 1, 0, 0, 0); | ||
63 | } | ||
64 | |||
65 | static int null_rtc_set_time(unsigned long sec) | ||
66 | { | ||
67 | return 0; | ||
68 | } | ||
69 | |||
70 | unsigned long (*rtc_get_time)(void) = null_rtc_get_time; | ||
71 | int (*rtc_set_time)(unsigned long) = null_rtc_set_time; | ||
72 | int (*rtc_set_mmss)(unsigned long); | ||
73 | |||
74 | |||
75 | /* usecs per counter cycle, shifted to left by 32 bits */ | ||
76 | static unsigned int sll32_usecs_per_cycle; | ||
77 | |||
78 | /* how many counter cycles in a jiffy */ | ||
79 | static unsigned long cycles_per_jiffy; | ||
80 | |||
81 | /* Cycle counter value at the previous timer interrupt.. */ | ||
82 | static unsigned int timerhi, timerlo; | ||
83 | |||
84 | /* expirelo is the count value for next CPU timer interrupt */ | ||
85 | static unsigned int expirelo; | ||
86 | |||
87 | |||
88 | /* | ||
89 | * Null timer ack for systems not needing one (e.g. i8254). | ||
90 | */ | ||
91 | static void null_timer_ack(void) { /* nothing */ } | ||
92 | |||
93 | /* | ||
94 | * Null high precision timer functions for systems lacking one. | ||
95 | */ | ||
96 | static unsigned int null_hpt_read(void) | ||
97 | { | ||
98 | return 0; | ||
99 | } | ||
100 | |||
101 | static void null_hpt_init(unsigned int count) { /* nothing */ } | ||
102 | |||
103 | |||
104 | /* | ||
105 | * Timer ack for an R4k-compatible timer of a known frequency. | ||
106 | */ | ||
107 | static void c0_timer_ack(void) | ||
108 | { | ||
109 | unsigned int count; | ||
110 | |||
111 | /* Ack this timer interrupt and set the next one. */ | ||
112 | expirelo += cycles_per_jiffy; | ||
113 | write_c0_compare(expirelo); | ||
114 | |||
115 | /* Check to see if we have missed any timer interrupts. */ | ||
116 | count = read_c0_count(); | ||
117 | if ((count - expirelo) < 0x7fffffff) { | ||
118 | /* missed_timer_count++; */ | ||
119 | expirelo = count + cycles_per_jiffy; | ||
120 | write_c0_compare(expirelo); | ||
121 | } | ||
122 | } | ||
123 | |||
124 | /* | ||
125 | * High precision timer functions for a R4k-compatible timer. | ||
126 | */ | ||
127 | static unsigned int c0_hpt_read(void) | ||
128 | { | ||
129 | return read_c0_count(); | ||
130 | } | ||
131 | |||
132 | /* For use solely as a high precision timer. */ | ||
133 | static void c0_hpt_init(unsigned int count) | ||
134 | { | ||
135 | write_c0_count(read_c0_count() - count); | ||
136 | } | ||
137 | |||
138 | /* For use both as a high precision timer and an interrupt source. */ | ||
139 | static void c0_hpt_timer_init(unsigned int count) | ||
140 | { | ||
141 | count = read_c0_count() - count; | ||
142 | expirelo = (count / cycles_per_jiffy + 1) * cycles_per_jiffy; | ||
143 | write_c0_count(expirelo - cycles_per_jiffy); | ||
144 | write_c0_compare(expirelo); | ||
145 | write_c0_count(count); | ||
146 | } | ||
147 | |||
148 | int (*mips_timer_state)(void); | ||
149 | void (*mips_timer_ack)(void); | ||
150 | unsigned int (*mips_hpt_read)(void); | ||
151 | void (*mips_hpt_init)(unsigned int); | ||
152 | |||
153 | |||
154 | /* | ||
155 | * This version of gettimeofday has microsecond resolution and better than | ||
156 | * microsecond precision on fast machines with cycle counter. | ||
157 | */ | ||
158 | void do_gettimeofday(struct timeval *tv) | ||
159 | { | ||
160 | unsigned long seq; | ||
161 | unsigned long lost; | ||
162 | unsigned long usec, sec; | ||
163 | unsigned long max_ntp_tick = tick_usec - tickadj; | ||
164 | |||
165 | do { | ||
166 | seq = read_seqbegin(&xtime_lock); | ||
167 | |||
168 | usec = do_gettimeoffset(); | ||
169 | |||
170 | lost = jiffies - wall_jiffies; | ||
171 | |||
172 | /* | ||
173 | * If time_adjust is negative then NTP is slowing the clock | ||
174 | * so make sure not to go into next possible interval. | ||
175 | * Better to lose some accuracy than have time go backwards.. | ||
176 | */ | ||
177 | if (unlikely(time_adjust < 0)) { | ||
178 | usec = min(usec, max_ntp_tick); | ||
179 | |||
180 | if (lost) | ||
181 | usec += lost * max_ntp_tick; | ||
182 | } else if (unlikely(lost)) | ||
183 | usec += lost * tick_usec; | ||
184 | |||
185 | sec = xtime.tv_sec; | ||
186 | usec += (xtime.tv_nsec / 1000); | ||
187 | |||
188 | } while (read_seqretry(&xtime_lock, seq)); | ||
189 | |||
190 | while (usec >= 1000000) { | ||
191 | usec -= 1000000; | ||
192 | sec++; | ||
193 | } | ||
194 | |||
195 | tv->tv_sec = sec; | ||
196 | tv->tv_usec = usec; | ||
197 | } | ||
198 | |||
199 | EXPORT_SYMBOL(do_gettimeofday); | ||
200 | |||
201 | int do_settimeofday(struct timespec *tv) | ||
202 | { | ||
203 | time_t wtm_sec, sec = tv->tv_sec; | ||
204 | long wtm_nsec, nsec = tv->tv_nsec; | ||
205 | |||
206 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | ||
207 | return -EINVAL; | ||
208 | |||
209 | write_seqlock_irq(&xtime_lock); | ||
210 | |||
211 | /* | ||
212 | * This is revolting. We need to set "xtime" correctly. However, | ||
213 | * the value in this location is the value at the most recent update | ||
214 | * of wall time. Discover what correction gettimeofday() would have | ||
215 | * made, and then undo it! | ||
216 | */ | ||
217 | nsec -= do_gettimeoffset() * NSEC_PER_USEC; | ||
218 | nsec -= (jiffies - wall_jiffies) * tick_nsec; | ||
219 | |||
220 | wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); | ||
221 | wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); | ||
222 | |||
223 | set_normalized_timespec(&xtime, sec, nsec); | ||
224 | set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); | ||
225 | |||
226 | time_adjust = 0; /* stop active adjtime() */ | ||
227 | time_status |= STA_UNSYNC; | ||
228 | time_maxerror = NTP_PHASE_LIMIT; | ||
229 | time_esterror = NTP_PHASE_LIMIT; | ||
230 | |||
231 | write_sequnlock_irq(&xtime_lock); | ||
232 | clock_was_set(); | ||
233 | return 0; | ||
234 | } | ||
235 | |||
236 | EXPORT_SYMBOL(do_settimeofday); | ||
237 | |||
238 | /* | ||
239 | * Gettimeoffset routines. These routines returns the time duration | ||
240 | * since last timer interrupt in usecs. | ||
241 | * | ||
242 | * If the exact CPU counter frequency is known, use fixed_rate_gettimeoffset. | ||
243 | * Otherwise use calibrate_gettimeoffset() | ||
244 | * | ||
245 | * If the CPU does not have the counter register, you can either supply | ||
246 | * your own gettimeoffset() routine, or use null_gettimeoffset(), which | ||
247 | * gives the same resolution as HZ. | ||
248 | */ | ||
249 | |||
250 | static unsigned long null_gettimeoffset(void) | ||
251 | { | ||
252 | return 0; | ||
253 | } | ||
254 | |||
255 | |||
256 | /* The function pointer to one of the gettimeoffset funcs. */ | ||
257 | unsigned long (*do_gettimeoffset)(void) = null_gettimeoffset; | ||
258 | |||
259 | |||
260 | static unsigned long fixed_rate_gettimeoffset(void) | ||
261 | { | ||
262 | u32 count; | ||
263 | unsigned long res; | ||
264 | |||
265 | /* Get last timer tick in absolute kernel time */ | ||
266 | count = mips_hpt_read(); | ||
267 | |||
268 | /* .. relative to previous jiffy (32 bits is enough) */ | ||
269 | count -= timerlo; | ||
270 | |||
271 | __asm__("multu %1,%2" | ||
272 | : "=h" (res) | ||
273 | : "r" (count), "r" (sll32_usecs_per_cycle) | ||
274 | : "lo", GCC_REG_ACCUM); | ||
275 | |||
276 | /* | ||
277 | * Due to possible jiffies inconsistencies, we need to check | ||
278 | * the result so that we'll get a timer that is monotonic. | ||
279 | */ | ||
280 | if (res >= USECS_PER_JIFFY) | ||
281 | res = USECS_PER_JIFFY - 1; | ||
282 | |||
283 | return res; | ||
284 | } | ||
285 | |||
286 | |||
287 | /* | ||
288 | * Cached "1/(clocks per usec) * 2^32" value. | ||
289 | * It has to be recalculated once each jiffy. | ||
290 | */ | ||
291 | static unsigned long cached_quotient; | ||
292 | |||
293 | /* Last jiffy when calibrate_divXX_gettimeoffset() was called. */ | ||
294 | static unsigned long last_jiffies; | ||
295 | |||
296 | /* | ||
297 | * This is moved from dec/time.c:do_ioasic_gettimeoffset() by Maciej. | ||
298 | */ | ||
299 | static unsigned long calibrate_div32_gettimeoffset(void) | ||
300 | { | ||
301 | u32 count; | ||
302 | unsigned long res, tmp; | ||
303 | unsigned long quotient; | ||
304 | |||
305 | tmp = jiffies; | ||
306 | |||
307 | quotient = cached_quotient; | ||
308 | |||
309 | if (last_jiffies != tmp) { | ||
310 | last_jiffies = tmp; | ||
311 | if (last_jiffies != 0) { | ||
312 | unsigned long r0; | ||
313 | do_div64_32(r0, timerhi, timerlo, tmp); | ||
314 | do_div64_32(quotient, USECS_PER_JIFFY, | ||
315 | USECS_PER_JIFFY_FRAC, r0); | ||
316 | cached_quotient = quotient; | ||
317 | } | ||
318 | } | ||
319 | |||
320 | /* Get last timer tick in absolute kernel time */ | ||
321 | count = mips_hpt_read(); | ||
322 | |||
323 | /* .. relative to previous jiffy (32 bits is enough) */ | ||
324 | count -= timerlo; | ||
325 | |||
326 | __asm__("multu %1,%2" | ||
327 | : "=h" (res) | ||
328 | : "r" (count), "r" (quotient) | ||
329 | : "lo", GCC_REG_ACCUM); | ||
330 | |||
331 | /* | ||
332 | * Due to possible jiffies inconsistencies, we need to check | ||
333 | * the result so that we'll get a timer that is monotonic. | ||
334 | */ | ||
335 | if (res >= USECS_PER_JIFFY) | ||
336 | res = USECS_PER_JIFFY - 1; | ||
337 | |||
338 | return res; | ||
339 | } | ||
340 | |||
341 | static unsigned long calibrate_div64_gettimeoffset(void) | ||
342 | { | ||
343 | u32 count; | ||
344 | unsigned long res, tmp; | ||
345 | unsigned long quotient; | ||
346 | |||
347 | tmp = jiffies; | ||
348 | |||
349 | quotient = cached_quotient; | ||
350 | |||
351 | if (last_jiffies != tmp) { | ||
352 | last_jiffies = tmp; | ||
353 | if (last_jiffies) { | ||
354 | unsigned long r0; | ||
355 | __asm__(".set push\n\t" | ||
356 | ".set mips3\n\t" | ||
357 | "lwu %0,%3\n\t" | ||
358 | "dsll32 %1,%2,0\n\t" | ||
359 | "or %1,%1,%0\n\t" | ||
360 | "ddivu $0,%1,%4\n\t" | ||
361 | "mflo %1\n\t" | ||
362 | "dsll32 %0,%5,0\n\t" | ||
363 | "or %0,%0,%6\n\t" | ||
364 | "ddivu $0,%0,%1\n\t" | ||
365 | "mflo %0\n\t" | ||
366 | ".set pop" | ||
367 | : "=&r" (quotient), "=&r" (r0) | ||
368 | : "r" (timerhi), "m" (timerlo), | ||
369 | "r" (tmp), "r" (USECS_PER_JIFFY), | ||
370 | "r" (USECS_PER_JIFFY_FRAC) | ||
371 | : "hi", "lo", GCC_REG_ACCUM); | ||
372 | cached_quotient = quotient; | ||
373 | } | ||
374 | } | ||
375 | |||
376 | /* Get last timer tick in absolute kernel time */ | ||
377 | count = mips_hpt_read(); | ||
378 | |||
379 | /* .. relative to previous jiffy (32 bits is enough) */ | ||
380 | count -= timerlo; | ||
381 | |||
382 | __asm__("multu %1,%2" | ||
383 | : "=h" (res) | ||
384 | : "r" (count), "r" (quotient) | ||
385 | : "lo", GCC_REG_ACCUM); | ||
386 | |||
387 | /* | ||
388 | * Due to possible jiffies inconsistencies, we need to check | ||
389 | * the result so that we'll get a timer that is monotonic. | ||
390 | */ | ||
391 | if (res >= USECS_PER_JIFFY) | ||
392 | res = USECS_PER_JIFFY - 1; | ||
393 | |||
394 | return res; | ||
395 | } | ||
396 | |||
397 | |||
398 | /* last time when xtime and rtc are sync'ed up */ | ||
399 | static long last_rtc_update; | ||
400 | |||
401 | /* | ||
402 | * local_timer_interrupt() does profiling and process accounting | ||
403 | * on a per-CPU basis. | ||
404 | * | ||
405 | * In UP mode, it is invoked from the (global) timer_interrupt. | ||
406 | * | ||
407 | * In SMP mode, it might invoked by per-CPU timer interrupt, or | ||
408 | * a broadcasted inter-processor interrupt which itself is triggered | ||
409 | * by the global timer interrupt. | ||
410 | */ | ||
411 | void local_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) | ||
412 | { | ||
413 | if (current->pid) | ||
414 | profile_tick(CPU_PROFILING, regs); | ||
415 | update_process_times(user_mode(regs)); | ||
416 | } | ||
417 | |||
418 | /* | ||
419 | * High-level timer interrupt service routines. This function | ||
420 | * is set as irqaction->handler and is invoked through do_IRQ. | ||
421 | */ | ||
422 | irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) | ||
423 | { | ||
424 | unsigned long j; | ||
425 | unsigned int count; | ||
426 | |||
427 | count = mips_hpt_read(); | ||
428 | mips_timer_ack(); | ||
429 | |||
430 | /* Update timerhi/timerlo for intra-jiffy calibration. */ | ||
431 | timerhi += count < timerlo; /* Wrap around */ | ||
432 | timerlo = count; | ||
433 | |||
434 | /* | ||
435 | * call the generic timer interrupt handling | ||
436 | */ | ||
437 | do_timer(regs); | ||
438 | |||
439 | /* | ||
440 | * If we have an externally synchronized Linux clock, then update | ||
441 | * CMOS clock accordingly every ~11 minutes. rtc_set_time() has to be | ||
442 | * called as close as possible to 500 ms before the new second starts. | ||
443 | */ | ||
444 | write_seqlock(&xtime_lock); | ||
445 | if ((time_status & STA_UNSYNC) == 0 && | ||
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) { | ||
449 | if (rtc_set_mmss(xtime.tv_sec) == 0) { | ||
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 | } | ||
456 | write_sequnlock(&xtime_lock); | ||
457 | |||
458 | /* | ||
459 | * If jiffies has overflown in this timer_interrupt, we must | ||
460 | * update the timer[hi]/[lo] to make fast gettimeoffset funcs | ||
461 | * quotient calc still valid. -arca | ||
462 | * | ||
463 | * The first timer interrupt comes late as interrupts are | ||
464 | * enabled long after timers are initialized. Therefore the | ||
465 | * high precision timer is fast, leading to wrong gettimeoffset() | ||
466 | * calculations. We deal with it by setting it based on the | ||
467 | * number of its ticks between the second and the third interrupt. | ||
468 | * That is still somewhat imprecise, but it's a good estimate. | ||
469 | * --macro | ||
470 | */ | ||
471 | j = jiffies; | ||
472 | if (j < 4) { | ||
473 | static unsigned int prev_count; | ||
474 | static int hpt_initialized; | ||
475 | |||
476 | switch (j) { | ||
477 | case 0: | ||
478 | timerhi = timerlo = 0; | ||
479 | mips_hpt_init(count); | ||
480 | break; | ||
481 | case 2: | ||
482 | prev_count = count; | ||
483 | break; | ||
484 | case 3: | ||
485 | if (!hpt_initialized) { | ||
486 | unsigned int c3 = 3 * (count - prev_count); | ||
487 | |||
488 | timerhi = 0; | ||
489 | timerlo = c3; | ||
490 | mips_hpt_init(count - c3); | ||
491 | hpt_initialized = 1; | ||
492 | } | ||
493 | break; | ||
494 | default: | ||
495 | break; | ||
496 | } | ||
497 | } | ||
498 | |||
499 | /* | ||
500 | * In UP mode, we call local_timer_interrupt() to do profiling | ||
501 | * and process accouting. | ||
502 | * | ||
503 | * In SMP mode, local_timer_interrupt() is invoked by appropriate | ||
504 | * low-level local timer interrupt handler. | ||
505 | */ | ||
506 | local_timer_interrupt(irq, dev_id, regs); | ||
507 | |||
508 | return IRQ_HANDLED; | ||
509 | } | ||
510 | |||
511 | asmlinkage void ll_timer_interrupt(int irq, struct pt_regs *regs) | ||
512 | { | ||
513 | irq_enter(); | ||
514 | kstat_this_cpu.irqs[irq]++; | ||
515 | |||
516 | /* we keep interrupt disabled all the time */ | ||
517 | timer_interrupt(irq, NULL, regs); | ||
518 | |||
519 | irq_exit(); | ||
520 | } | ||
521 | |||
522 | asmlinkage void ll_local_timer_interrupt(int irq, struct pt_regs *regs) | ||
523 | { | ||
524 | irq_enter(); | ||
525 | if (smp_processor_id() != 0) | ||
526 | kstat_this_cpu.irqs[irq]++; | ||
527 | |||
528 | /* we keep interrupt disabled all the time */ | ||
529 | local_timer_interrupt(irq, NULL, regs); | ||
530 | |||
531 | irq_exit(); | ||
532 | } | ||
533 | |||
534 | /* | ||
535 | * time_init() - it does the following things. | ||
536 | * | ||
537 | * 1) board_time_init() - | ||
538 | * a) (optional) set up RTC routines, | ||
539 | * b) (optional) calibrate and set the mips_hpt_frequency | ||
540 | * (only needed if you intended to use fixed_rate_gettimeoffset | ||
541 | * or use cpu counter as timer interrupt source) | ||
542 | * 2) setup xtime based on rtc_get_time(). | ||
543 | * 3) choose a appropriate gettimeoffset routine. | ||
544 | * 4) calculate a couple of cached variables for later usage | ||
545 | * 5) board_timer_setup() - | ||
546 | * a) (optional) over-write any choices made above by time_init(). | ||
547 | * b) machine specific code should setup the timer irqaction. | ||
548 | * c) enable the timer interrupt | ||
549 | */ | ||
550 | |||
551 | void (*board_time_init)(void); | ||
552 | void (*board_timer_setup)(struct irqaction *irq); | ||
553 | |||
554 | unsigned int mips_hpt_frequency; | ||
555 | |||
556 | static struct irqaction timer_irqaction = { | ||
557 | .handler = timer_interrupt, | ||
558 | .flags = SA_INTERRUPT, | ||
559 | .name = "timer", | ||
560 | }; | ||
561 | |||
562 | static unsigned int __init calibrate_hpt(void) | ||
563 | { | ||
564 | u64 frequency; | ||
565 | u32 hpt_start, hpt_end, hpt_count, hz; | ||
566 | |||
567 | const int loops = HZ / 10; | ||
568 | int log_2_loops = 0; | ||
569 | int i; | ||
570 | |||
571 | /* | ||
572 | * We want to calibrate for 0.1s, but to avoid a 64-bit | ||
573 | * division we round the number of loops up to the nearest | ||
574 | * power of 2. | ||
575 | */ | ||
576 | while (loops > 1 << log_2_loops) | ||
577 | log_2_loops++; | ||
578 | i = 1 << log_2_loops; | ||
579 | |||
580 | /* | ||
581 | * Wait for a rising edge of the timer interrupt. | ||
582 | */ | ||
583 | while (mips_timer_state()); | ||
584 | while (!mips_timer_state()); | ||
585 | |||
586 | /* | ||
587 | * Now see how many high precision timer ticks happen | ||
588 | * during the calculated number of periods between timer | ||
589 | * interrupts. | ||
590 | */ | ||
591 | hpt_start = mips_hpt_read(); | ||
592 | do { | ||
593 | while (mips_timer_state()); | ||
594 | while (!mips_timer_state()); | ||
595 | } while (--i); | ||
596 | hpt_end = mips_hpt_read(); | ||
597 | |||
598 | hpt_count = hpt_end - hpt_start; | ||
599 | hz = HZ; | ||
600 | frequency = (u64)hpt_count * (u64)hz; | ||
601 | |||
602 | return frequency >> log_2_loops; | ||
603 | } | ||
604 | |||
605 | void __init time_init(void) | ||
606 | { | ||
607 | if (board_time_init) | ||
608 | board_time_init(); | ||
609 | |||
610 | if (!rtc_set_mmss) | ||
611 | rtc_set_mmss = rtc_set_time; | ||
612 | |||
613 | xtime.tv_sec = rtc_get_time(); | ||
614 | xtime.tv_nsec = 0; | ||
615 | |||
616 | set_normalized_timespec(&wall_to_monotonic, | ||
617 | -xtime.tv_sec, -xtime.tv_nsec); | ||
618 | |||
619 | /* Choose appropriate high precision timer routines. */ | ||
620 | if (!cpu_has_counter && !mips_hpt_read) { | ||
621 | /* No high precision timer -- sorry. */ | ||
622 | mips_hpt_read = null_hpt_read; | ||
623 | mips_hpt_init = null_hpt_init; | ||
624 | } else if (!mips_hpt_frequency && !mips_timer_state) { | ||
625 | /* A high precision timer of unknown frequency. */ | ||
626 | if (!mips_hpt_read) { | ||
627 | /* No external high precision timer -- use R4k. */ | ||
628 | mips_hpt_read = c0_hpt_read; | ||
629 | mips_hpt_init = c0_hpt_init; | ||
630 | } | ||
631 | |||
632 | if ((current_cpu_data.isa_level == MIPS_CPU_ISA_M32) || | ||
633 | (current_cpu_data.isa_level == MIPS_CPU_ISA_I) || | ||
634 | (current_cpu_data.isa_level == MIPS_CPU_ISA_II)) | ||
635 | /* | ||
636 | * We need to calibrate the counter but we don't have | ||
637 | * 64-bit division. | ||
638 | */ | ||
639 | do_gettimeoffset = calibrate_div32_gettimeoffset; | ||
640 | else | ||
641 | /* | ||
642 | * We need to calibrate the counter but we *do* have | ||
643 | * 64-bit division. | ||
644 | */ | ||
645 | do_gettimeoffset = calibrate_div64_gettimeoffset; | ||
646 | } else { | ||
647 | /* We know counter frequency. Or we can get it. */ | ||
648 | if (!mips_hpt_read) { | ||
649 | /* No external high precision timer -- use R4k. */ | ||
650 | mips_hpt_read = c0_hpt_read; | ||
651 | |||
652 | if (mips_timer_state) | ||
653 | mips_hpt_init = c0_hpt_init; | ||
654 | else { | ||
655 | /* No external timer interrupt -- use R4k. */ | ||
656 | mips_hpt_init = c0_hpt_timer_init; | ||
657 | mips_timer_ack = c0_timer_ack; | ||
658 | } | ||
659 | } | ||
660 | if (!mips_hpt_frequency) | ||
661 | mips_hpt_frequency = calibrate_hpt(); | ||
662 | |||
663 | do_gettimeoffset = fixed_rate_gettimeoffset; | ||
664 | |||
665 | /* Calculate cache parameters. */ | ||
666 | cycles_per_jiffy = (mips_hpt_frequency + HZ / 2) / HZ; | ||
667 | |||
668 | /* sll32_usecs_per_cycle = 10^6 * 2^32 / mips_counter_freq */ | ||
669 | do_div64_32(sll32_usecs_per_cycle, | ||
670 | 1000000, mips_hpt_frequency / 2, | ||
671 | mips_hpt_frequency); | ||
672 | |||
673 | /* Report the high precision timer rate for a reference. */ | ||
674 | printk("Using %u.%03u MHz high precision timer.\n", | ||
675 | ((mips_hpt_frequency + 500) / 1000) / 1000, | ||
676 | ((mips_hpt_frequency + 500) / 1000) % 1000); | ||
677 | } | ||
678 | |||
679 | if (!mips_timer_ack) | ||
680 | /* No timer interrupt ack (e.g. i8254). */ | ||
681 | mips_timer_ack = null_timer_ack; | ||
682 | |||
683 | /* This sets up the high precision timer for the first interrupt. */ | ||
684 | mips_hpt_init(mips_hpt_read()); | ||
685 | |||
686 | /* | ||
687 | * Call board specific timer interrupt setup. | ||
688 | * | ||
689 | * this pointer must be setup in machine setup routine. | ||
690 | * | ||
691 | * Even if a machine chooses to use a low-level timer interrupt, | ||
692 | * it still needs to setup the timer_irqaction. | ||
693 | * In that case, it might be better to set timer_irqaction.handler | ||
694 | * to be NULL function so that we are sure the high-level code | ||
695 | * is not invoked accidentally. | ||
696 | */ | ||
697 | board_timer_setup(&timer_irqaction); | ||
698 | } | ||
699 | |||
700 | #define FEBRUARY 2 | ||
701 | #define STARTOFTIME 1970 | ||
702 | #define SECDAY 86400L | ||
703 | #define SECYR (SECDAY * 365) | ||
704 | #define leapyear(y) ((!((y) % 4) && ((y) % 100)) || !((y) % 400)) | ||
705 | #define days_in_year(y) (leapyear(y) ? 366 : 365) | ||
706 | #define days_in_month(m) (month_days[(m) - 1]) | ||
707 | |||
708 | static int month_days[12] = { | ||
709 | 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 | ||
710 | }; | ||
711 | |||
712 | void to_tm(unsigned long tim, struct rtc_time *tm) | ||
713 | { | ||
714 | long hms, day, gday; | ||
715 | int i; | ||
716 | |||
717 | gday = day = tim / SECDAY; | ||
718 | hms = tim % SECDAY; | ||
719 | |||
720 | /* Hours, minutes, seconds are easy */ | ||
721 | tm->tm_hour = hms / 3600; | ||
722 | tm->tm_min = (hms % 3600) / 60; | ||
723 | tm->tm_sec = (hms % 3600) % 60; | ||
724 | |||
725 | /* Number of years in days */ | ||
726 | for (i = STARTOFTIME; day >= days_in_year(i); i++) | ||
727 | day -= days_in_year(i); | ||
728 | tm->tm_year = i; | ||
729 | |||
730 | /* Number of months in days left */ | ||
731 | if (leapyear(tm->tm_year)) | ||
732 | days_in_month(FEBRUARY) = 29; | ||
733 | for (i = 1; day >= days_in_month(i); i++) | ||
734 | day -= days_in_month(i); | ||
735 | days_in_month(FEBRUARY) = 28; | ||
736 | tm->tm_mon = i - 1; /* tm_mon starts from 0 to 11 */ | ||
737 | |||
738 | /* Days are what is left over (+1) from all that. */ | ||
739 | tm->tm_mday = day + 1; | ||
740 | |||
741 | /* | ||
742 | * Determine the day of week | ||
743 | */ | ||
744 | tm->tm_wday = (gday + 4) % 7; /* 1970/1/1 was Thursday */ | ||
745 | } | ||
746 | |||
747 | EXPORT_SYMBOL(rtc_lock); | ||
748 | EXPORT_SYMBOL(to_tm); | ||
749 | EXPORT_SYMBOL(rtc_set_time); | ||
750 | EXPORT_SYMBOL(rtc_get_time); | ||
751 | |||
752 | unsigned long long sched_clock(void) | ||
753 | { | ||
754 | return (unsigned long long)jiffies*(1000000000/HZ); | ||
755 | } | ||