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1da177e4 LT |
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 | } |