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Diffstat (limited to 'arch/i386/kernel/time.c')
-rw-r--r-- | arch/i386/kernel/time.c | 476 |
1 files changed, 476 insertions, 0 deletions
diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c new file mode 100644 index 000000000000..9b55e30e4490 --- /dev/null +++ b/arch/i386/kernel/time.c | |||
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1 | /* | ||
2 | * linux/arch/i386/kernel/time.c | ||
3 | * | ||
4 | * Copyright (C) 1991, 1992, 1995 Linus Torvalds | ||
5 | * | ||
6 | * This file contains the PC-specific time handling details: | ||
7 | * reading the RTC at bootup, etc.. | ||
8 | * 1994-07-02 Alan Modra | ||
9 | * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime | ||
10 | * 1995-03-26 Markus Kuhn | ||
11 | * fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887 | ||
12 | * precision CMOS clock update | ||
13 | * 1996-05-03 Ingo Molnar | ||
14 | * fixed time warps in do_[slow|fast]_gettimeoffset() | ||
15 | * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 | ||
16 | * "A Kernel Model for Precision Timekeeping" by Dave Mills | ||
17 | * 1998-09-05 (Various) | ||
18 | * More robust do_fast_gettimeoffset() algorithm implemented | ||
19 | * (works with APM, Cyrix 6x86MX and Centaur C6), | ||
20 | * monotonic gettimeofday() with fast_get_timeoffset(), | ||
21 | * drift-proof precision TSC calibration on boot | ||
22 | * (C. Scott Ananian <cananian@alumni.princeton.edu>, Andrew D. | ||
23 | * Balsa <andrebalsa@altern.org>, Philip Gladstone <philip@raptor.com>; | ||
24 | * ported from 2.0.35 Jumbo-9 by Michael Krause <m.krause@tu-harburg.de>). | ||
25 | * 1998-12-16 Andrea Arcangeli | ||
26 | * Fixed Jumbo-9 code in 2.1.131: do_gettimeofday was missing 1 jiffy | ||
27 | * because was not accounting lost_ticks. | ||
28 | * 1998-12-24 Copyright (C) 1998 Andrea Arcangeli | ||
29 | * Fixed a xtime SMP race (we need the xtime_lock rw spinlock to | ||
30 | * serialize accesses to xtime/lost_ticks). | ||
31 | */ | ||
32 | |||
33 | #include <linux/errno.h> | ||
34 | #include <linux/sched.h> | ||
35 | #include <linux/kernel.h> | ||
36 | #include <linux/param.h> | ||
37 | #include <linux/string.h> | ||
38 | #include <linux/mm.h> | ||
39 | #include <linux/interrupt.h> | ||
40 | #include <linux/time.h> | ||
41 | #include <linux/delay.h> | ||
42 | #include <linux/init.h> | ||
43 | #include <linux/smp.h> | ||
44 | #include <linux/module.h> | ||
45 | #include <linux/sysdev.h> | ||
46 | #include <linux/bcd.h> | ||
47 | #include <linux/efi.h> | ||
48 | #include <linux/mca.h> | ||
49 | |||
50 | #include <asm/io.h> | ||
51 | #include <asm/smp.h> | ||
52 | #include <asm/irq.h> | ||
53 | #include <asm/msr.h> | ||
54 | #include <asm/delay.h> | ||
55 | #include <asm/mpspec.h> | ||
56 | #include <asm/uaccess.h> | ||
57 | #include <asm/processor.h> | ||
58 | #include <asm/timer.h> | ||
59 | |||
60 | #include "mach_time.h" | ||
61 | |||
62 | #include <linux/timex.h> | ||
63 | #include <linux/config.h> | ||
64 | |||
65 | #include <asm/hpet.h> | ||
66 | |||
67 | #include <asm/arch_hooks.h> | ||
68 | |||
69 | #include "io_ports.h" | ||
70 | |||
71 | extern spinlock_t i8259A_lock; | ||
72 | int pit_latch_buggy; /* extern */ | ||
73 | |||
74 | #include "do_timer.h" | ||
75 | |||
76 | u64 jiffies_64 = INITIAL_JIFFIES; | ||
77 | |||
78 | EXPORT_SYMBOL(jiffies_64); | ||
79 | |||
80 | unsigned long cpu_khz; /* Detected as we calibrate the TSC */ | ||
81 | |||
82 | extern unsigned long wall_jiffies; | ||
83 | |||
84 | DEFINE_SPINLOCK(rtc_lock); | ||
85 | |||
86 | DEFINE_SPINLOCK(i8253_lock); | ||
87 | EXPORT_SYMBOL(i8253_lock); | ||
88 | |||
89 | struct timer_opts *cur_timer = &timer_none; | ||
90 | |||
91 | /* | ||
92 | * This is a special lock that is owned by the CPU and holds the index | ||
93 | * register we are working with. It is required for NMI access to the | ||
94 | * CMOS/RTC registers. See include/asm-i386/mc146818rtc.h for details. | ||
95 | */ | ||
96 | volatile unsigned long cmos_lock = 0; | ||
97 | EXPORT_SYMBOL(cmos_lock); | ||
98 | |||
99 | /* Routines for accessing the CMOS RAM/RTC. */ | ||
100 | unsigned char rtc_cmos_read(unsigned char addr) | ||
101 | { | ||
102 | unsigned char val; | ||
103 | lock_cmos_prefix(addr); | ||
104 | outb_p(addr, RTC_PORT(0)); | ||
105 | val = inb_p(RTC_PORT(1)); | ||
106 | lock_cmos_suffix(addr); | ||
107 | return val; | ||
108 | } | ||
109 | EXPORT_SYMBOL(rtc_cmos_read); | ||
110 | |||
111 | void rtc_cmos_write(unsigned char val, unsigned char addr) | ||
112 | { | ||
113 | lock_cmos_prefix(addr); | ||
114 | outb_p(addr, RTC_PORT(0)); | ||
115 | outb_p(val, RTC_PORT(1)); | ||
116 | lock_cmos_suffix(addr); | ||
117 | } | ||
118 | EXPORT_SYMBOL(rtc_cmos_write); | ||
119 | |||
120 | /* | ||
121 | * This version of gettimeofday has microsecond resolution | ||
122 | * and better than microsecond precision on fast x86 machines with TSC. | ||
123 | */ | ||
124 | void do_gettimeofday(struct timeval *tv) | ||
125 | { | ||
126 | unsigned long seq; | ||
127 | unsigned long usec, sec; | ||
128 | unsigned long max_ntp_tick; | ||
129 | |||
130 | do { | ||
131 | unsigned long lost; | ||
132 | |||
133 | seq = read_seqbegin(&xtime_lock); | ||
134 | |||
135 | usec = cur_timer->get_offset(); | ||
136 | lost = jiffies - wall_jiffies; | ||
137 | |||
138 | /* | ||
139 | * If time_adjust is negative then NTP is slowing the clock | ||
140 | * so make sure not to go into next possible interval. | ||
141 | * Better to lose some accuracy than have time go backwards.. | ||
142 | */ | ||
143 | if (unlikely(time_adjust < 0)) { | ||
144 | max_ntp_tick = (USEC_PER_SEC / HZ) - tickadj; | ||
145 | usec = min(usec, max_ntp_tick); | ||
146 | |||
147 | if (lost) | ||
148 | usec += lost * max_ntp_tick; | ||
149 | } | ||
150 | else if (unlikely(lost)) | ||
151 | usec += lost * (USEC_PER_SEC / HZ); | ||
152 | |||
153 | sec = xtime.tv_sec; | ||
154 | usec += (xtime.tv_nsec / 1000); | ||
155 | } while (read_seqretry(&xtime_lock, seq)); | ||
156 | |||
157 | while (usec >= 1000000) { | ||
158 | usec -= 1000000; | ||
159 | sec++; | ||
160 | } | ||
161 | |||
162 | tv->tv_sec = sec; | ||
163 | tv->tv_usec = usec; | ||
164 | } | ||
165 | |||
166 | EXPORT_SYMBOL(do_gettimeofday); | ||
167 | |||
168 | int do_settimeofday(struct timespec *tv) | ||
169 | { | ||
170 | time_t wtm_sec, sec = tv->tv_sec; | ||
171 | long wtm_nsec, nsec = tv->tv_nsec; | ||
172 | |||
173 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | ||
174 | return -EINVAL; | ||
175 | |||
176 | write_seqlock_irq(&xtime_lock); | ||
177 | /* | ||
178 | * This is revolting. We need to set "xtime" correctly. However, the | ||
179 | * value in this location is the value at the most recent update of | ||
180 | * wall time. Discover what correction gettimeofday() would have | ||
181 | * made, and then undo it! | ||
182 | */ | ||
183 | nsec -= cur_timer->get_offset() * NSEC_PER_USEC; | ||
184 | nsec -= (jiffies - wall_jiffies) * TICK_NSEC; | ||
185 | |||
186 | wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); | ||
187 | wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); | ||
188 | |||
189 | set_normalized_timespec(&xtime, sec, nsec); | ||
190 | set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); | ||
191 | |||
192 | time_adjust = 0; /* stop active adjtime() */ | ||
193 | time_status |= STA_UNSYNC; | ||
194 | time_maxerror = NTP_PHASE_LIMIT; | ||
195 | time_esterror = NTP_PHASE_LIMIT; | ||
196 | write_sequnlock_irq(&xtime_lock); | ||
197 | clock_was_set(); | ||
198 | return 0; | ||
199 | } | ||
200 | |||
201 | EXPORT_SYMBOL(do_settimeofday); | ||
202 | |||
203 | static int set_rtc_mmss(unsigned long nowtime) | ||
204 | { | ||
205 | int retval; | ||
206 | |||
207 | WARN_ON(irqs_disabled()); | ||
208 | |||
209 | /* gets recalled with irq locally disabled */ | ||
210 | spin_lock_irq(&rtc_lock); | ||
211 | if (efi_enabled) | ||
212 | retval = efi_set_rtc_mmss(nowtime); | ||
213 | else | ||
214 | retval = mach_set_rtc_mmss(nowtime); | ||
215 | spin_unlock_irq(&rtc_lock); | ||
216 | |||
217 | return retval; | ||
218 | } | ||
219 | |||
220 | |||
221 | int timer_ack; | ||
222 | |||
223 | /* monotonic_clock(): returns # of nanoseconds passed since time_init() | ||
224 | * Note: This function is required to return accurate | ||
225 | * time even in the absence of multiple timer ticks. | ||
226 | */ | ||
227 | unsigned long long monotonic_clock(void) | ||
228 | { | ||
229 | return cur_timer->monotonic_clock(); | ||
230 | } | ||
231 | EXPORT_SYMBOL(monotonic_clock); | ||
232 | |||
233 | #if defined(CONFIG_SMP) && defined(CONFIG_FRAME_POINTER) | ||
234 | unsigned long profile_pc(struct pt_regs *regs) | ||
235 | { | ||
236 | unsigned long pc = instruction_pointer(regs); | ||
237 | |||
238 | if (in_lock_functions(pc)) | ||
239 | return *(unsigned long *)(regs->ebp + 4); | ||
240 | |||
241 | return pc; | ||
242 | } | ||
243 | EXPORT_SYMBOL(profile_pc); | ||
244 | #endif | ||
245 | |||
246 | /* | ||
247 | * timer_interrupt() needs to keep up the real-time clock, | ||
248 | * as well as call the "do_timer()" routine every clocktick | ||
249 | */ | ||
250 | static inline void do_timer_interrupt(int irq, void *dev_id, | ||
251 | struct pt_regs *regs) | ||
252 | { | ||
253 | #ifdef CONFIG_X86_IO_APIC | ||
254 | if (timer_ack) { | ||
255 | /* | ||
256 | * Subtle, when I/O APICs are used we have to ack timer IRQ | ||
257 | * manually to reset the IRR bit for do_slow_gettimeoffset(). | ||
258 | * This will also deassert NMI lines for the watchdog if run | ||
259 | * on an 82489DX-based system. | ||
260 | */ | ||
261 | spin_lock(&i8259A_lock); | ||
262 | outb(0x0c, PIC_MASTER_OCW3); | ||
263 | /* Ack the IRQ; AEOI will end it automatically. */ | ||
264 | inb(PIC_MASTER_POLL); | ||
265 | spin_unlock(&i8259A_lock); | ||
266 | } | ||
267 | #endif | ||
268 | |||
269 | do_timer_interrupt_hook(regs); | ||
270 | |||
271 | |||
272 | if (MCA_bus) { | ||
273 | /* The PS/2 uses level-triggered interrupts. You can't | ||
274 | turn them off, nor would you want to (any attempt to | ||
275 | enable edge-triggered interrupts usually gets intercepted by a | ||
276 | special hardware circuit). Hence we have to acknowledge | ||
277 | the timer interrupt. Through some incredibly stupid | ||
278 | design idea, the reset for IRQ 0 is done by setting the | ||
279 | high bit of the PPI port B (0x61). Note that some PS/2s, | ||
280 | notably the 55SX, work fine if this is removed. */ | ||
281 | |||
282 | irq = inb_p( 0x61 ); /* read the current state */ | ||
283 | outb_p( irq|0x80, 0x61 ); /* reset the IRQ */ | ||
284 | } | ||
285 | } | ||
286 | |||
287 | /* | ||
288 | * This is the same as the above, except we _also_ save the current | ||
289 | * Time Stamp Counter value at the time of the timer interrupt, so that | ||
290 | * we later on can estimate the time of day more exactly. | ||
291 | */ | ||
292 | irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) | ||
293 | { | ||
294 | /* | ||
295 | * Here we are in the timer irq handler. We just have irqs locally | ||
296 | * disabled but we don't know if the timer_bh is running on the other | ||
297 | * CPU. We need to avoid to SMP race with it. NOTE: we don' t need | ||
298 | * the irq version of write_lock because as just said we have irq | ||
299 | * locally disabled. -arca | ||
300 | */ | ||
301 | write_seqlock(&xtime_lock); | ||
302 | |||
303 | cur_timer->mark_offset(); | ||
304 | |||
305 | do_timer_interrupt(irq, NULL, regs); | ||
306 | |||
307 | write_sequnlock(&xtime_lock); | ||
308 | return IRQ_HANDLED; | ||
309 | } | ||
310 | |||
311 | /* not static: needed by APM */ | ||
312 | unsigned long get_cmos_time(void) | ||
313 | { | ||
314 | unsigned long retval; | ||
315 | |||
316 | spin_lock(&rtc_lock); | ||
317 | |||
318 | if (efi_enabled) | ||
319 | retval = efi_get_time(); | ||
320 | else | ||
321 | retval = mach_get_cmos_time(); | ||
322 | |||
323 | spin_unlock(&rtc_lock); | ||
324 | |||
325 | return retval; | ||
326 | } | ||
327 | static void sync_cmos_clock(unsigned long dummy); | ||
328 | |||
329 | static struct timer_list sync_cmos_timer = | ||
330 | TIMER_INITIALIZER(sync_cmos_clock, 0, 0); | ||
331 | |||
332 | static void sync_cmos_clock(unsigned long dummy) | ||
333 | { | ||
334 | struct timeval now, next; | ||
335 | int fail = 1; | ||
336 | |||
337 | /* | ||
338 | * If we have an externally synchronized Linux clock, then update | ||
339 | * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be | ||
340 | * called as close as possible to 500 ms before the new second starts. | ||
341 | * This code is run on a timer. If the clock is set, that timer | ||
342 | * may not expire at the correct time. Thus, we adjust... | ||
343 | */ | ||
344 | if ((time_status & STA_UNSYNC) != 0) | ||
345 | /* | ||
346 | * Not synced, exit, do not restart a timer (if one is | ||
347 | * running, let it run out). | ||
348 | */ | ||
349 | return; | ||
350 | |||
351 | do_gettimeofday(&now); | ||
352 | if (now.tv_usec >= USEC_AFTER - ((unsigned) TICK_SIZE) / 2 && | ||
353 | now.tv_usec <= USEC_BEFORE + ((unsigned) TICK_SIZE) / 2) | ||
354 | fail = set_rtc_mmss(now.tv_sec); | ||
355 | |||
356 | next.tv_usec = USEC_AFTER - now.tv_usec; | ||
357 | if (next.tv_usec <= 0) | ||
358 | next.tv_usec += USEC_PER_SEC; | ||
359 | |||
360 | if (!fail) | ||
361 | next.tv_sec = 659; | ||
362 | else | ||
363 | next.tv_sec = 0; | ||
364 | |||
365 | if (next.tv_usec >= USEC_PER_SEC) { | ||
366 | next.tv_sec++; | ||
367 | next.tv_usec -= USEC_PER_SEC; | ||
368 | } | ||
369 | mod_timer(&sync_cmos_timer, jiffies + timeval_to_jiffies(&next)); | ||
370 | } | ||
371 | |||
372 | void notify_arch_cmos_timer(void) | ||
373 | { | ||
374 | mod_timer(&sync_cmos_timer, jiffies + 1); | ||
375 | } | ||
376 | |||
377 | static long clock_cmos_diff, sleep_start; | ||
378 | |||
379 | static int timer_suspend(struct sys_device *dev, u32 state) | ||
380 | { | ||
381 | /* | ||
382 | * Estimate time zone so that set_time can update the clock | ||
383 | */ | ||
384 | clock_cmos_diff = -get_cmos_time(); | ||
385 | clock_cmos_diff += get_seconds(); | ||
386 | sleep_start = get_cmos_time(); | ||
387 | return 0; | ||
388 | } | ||
389 | |||
390 | static int timer_resume(struct sys_device *dev) | ||
391 | { | ||
392 | unsigned long flags; | ||
393 | unsigned long sec; | ||
394 | unsigned long sleep_length; | ||
395 | |||
396 | #ifdef CONFIG_HPET_TIMER | ||
397 | if (is_hpet_enabled()) | ||
398 | hpet_reenable(); | ||
399 | #endif | ||
400 | sec = get_cmos_time() + clock_cmos_diff; | ||
401 | sleep_length = (get_cmos_time() - sleep_start) * HZ; | ||
402 | write_seqlock_irqsave(&xtime_lock, flags); | ||
403 | xtime.tv_sec = sec; | ||
404 | xtime.tv_nsec = 0; | ||
405 | write_sequnlock_irqrestore(&xtime_lock, flags); | ||
406 | jiffies += sleep_length; | ||
407 | wall_jiffies += sleep_length; | ||
408 | return 0; | ||
409 | } | ||
410 | |||
411 | static struct sysdev_class timer_sysclass = { | ||
412 | .resume = timer_resume, | ||
413 | .suspend = timer_suspend, | ||
414 | set_kset_name("timer"), | ||
415 | }; | ||
416 | |||
417 | |||
418 | /* XXX this driverfs stuff should probably go elsewhere later -john */ | ||
419 | static struct sys_device device_timer = { | ||
420 | .id = 0, | ||
421 | .cls = &timer_sysclass, | ||
422 | }; | ||
423 | |||
424 | static int time_init_device(void) | ||
425 | { | ||
426 | int error = sysdev_class_register(&timer_sysclass); | ||
427 | if (!error) | ||
428 | error = sysdev_register(&device_timer); | ||
429 | return error; | ||
430 | } | ||
431 | |||
432 | device_initcall(time_init_device); | ||
433 | |||
434 | #ifdef CONFIG_HPET_TIMER | ||
435 | extern void (*late_time_init)(void); | ||
436 | /* Duplicate of time_init() below, with hpet_enable part added */ | ||
437 | static void __init hpet_time_init(void) | ||
438 | { | ||
439 | xtime.tv_sec = get_cmos_time(); | ||
440 | xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ); | ||
441 | set_normalized_timespec(&wall_to_monotonic, | ||
442 | -xtime.tv_sec, -xtime.tv_nsec); | ||
443 | |||
444 | if (hpet_enable() >= 0) { | ||
445 | printk("Using HPET for base-timer\n"); | ||
446 | } | ||
447 | |||
448 | cur_timer = select_timer(); | ||
449 | printk(KERN_INFO "Using %s for high-res timesource\n",cur_timer->name); | ||
450 | |||
451 | time_init_hook(); | ||
452 | } | ||
453 | #endif | ||
454 | |||
455 | void __init time_init(void) | ||
456 | { | ||
457 | #ifdef CONFIG_HPET_TIMER | ||
458 | if (is_hpet_capable()) { | ||
459 | /* | ||
460 | * HPET initialization needs to do memory-mapped io. So, let | ||
461 | * us do a late initialization after mem_init(). | ||
462 | */ | ||
463 | late_time_init = hpet_time_init; | ||
464 | return; | ||
465 | } | ||
466 | #endif | ||
467 | xtime.tv_sec = get_cmos_time(); | ||
468 | xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ); | ||
469 | set_normalized_timespec(&wall_to_monotonic, | ||
470 | -xtime.tv_sec, -xtime.tv_nsec); | ||
471 | |||
472 | cur_timer = select_timer(); | ||
473 | printk(KERN_INFO "Using %s for high-res timesource\n",cur_timer->name); | ||
474 | |||
475 | time_init_hook(); | ||
476 | } | ||