aboutsummaryrefslogtreecommitdiffstats
path: root/arch/i386/kernel/time.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/i386/kernel/time.c')
-rw-r--r--arch/i386/kernel/time.c476
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
@@ -0,0 +1,476 @@
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
71extern spinlock_t i8259A_lock;
72int pit_latch_buggy; /* extern */
73
74#include "do_timer.h"
75
76u64 jiffies_64 = INITIAL_JIFFIES;
77
78EXPORT_SYMBOL(jiffies_64);
79
80unsigned long cpu_khz; /* Detected as we calibrate the TSC */
81
82extern unsigned long wall_jiffies;
83
84DEFINE_SPINLOCK(rtc_lock);
85
86DEFINE_SPINLOCK(i8253_lock);
87EXPORT_SYMBOL(i8253_lock);
88
89struct 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 */
96volatile unsigned long cmos_lock = 0;
97EXPORT_SYMBOL(cmos_lock);
98
99/* Routines for accessing the CMOS RAM/RTC. */
100unsigned 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}
109EXPORT_SYMBOL(rtc_cmos_read);
110
111void 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}
118EXPORT_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 */
124void 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
166EXPORT_SYMBOL(do_gettimeofday);
167
168int 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
201EXPORT_SYMBOL(do_settimeofday);
202
203static 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
221int 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 */
227unsigned long long monotonic_clock(void)
228{
229 return cur_timer->monotonic_clock();
230}
231EXPORT_SYMBOL(monotonic_clock);
232
233#if defined(CONFIG_SMP) && defined(CONFIG_FRAME_POINTER)
234unsigned 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}
243EXPORT_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 */
250static 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 */
292irqreturn_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 */
312unsigned 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}
327static void sync_cmos_clock(unsigned long dummy);
328
329static struct timer_list sync_cmos_timer =
330 TIMER_INITIALIZER(sync_cmos_clock, 0, 0);
331
332static 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
372void notify_arch_cmos_timer(void)
373{
374 mod_timer(&sync_cmos_timer, jiffies + 1);
375}
376
377static long clock_cmos_diff, sleep_start;
378
379static 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
390static 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
411static 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 */
419static struct sys_device device_timer = {
420 .id = 0,
421 .cls = &timer_sysclass,
422};
423
424static 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
432device_initcall(time_init_device);
433
434#ifdef CONFIG_HPET_TIMER
435extern void (*late_time_init)(void);
436/* Duplicate of time_init() below, with hpet_enable part added */
437static 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
455void __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}