Merge tag 'locks-v3.16-2' of git://git.samba.org/jlayton/linux
[linux/fpc-iii.git] / arch / powerpc / kernel / time.c
blob9fff9cdcc5196c3a20b9129d7e407c1dbc113cb7
1 /*
2 * Common time routines among all ppc machines.
4 * Written by Cort Dougan (cort@cs.nmt.edu) to merge
5 * Paul Mackerras' version and mine for PReP and Pmac.
6 * MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net).
7 * Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com)
9 * First round of bugfixes by Gabriel Paubert (paubert@iram.es)
10 * to make clock more stable (2.4.0-test5). The only thing
11 * that this code assumes is that the timebases have been synchronized
12 * by firmware on SMP and are never stopped (never do sleep
13 * on SMP then, nap and doze are OK).
15 * Speeded up do_gettimeofday by getting rid of references to
16 * xtime (which required locks for consistency). (mikejc@us.ibm.com)
18 * TODO (not necessarily in this file):
19 * - improve precision and reproducibility of timebase frequency
20 * measurement at boot time.
21 * - for astronomical applications: add a new function to get
22 * non ambiguous timestamps even around leap seconds. This needs
23 * a new timestamp format and a good name.
25 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
26 * "A Kernel Model for Precision Timekeeping" by Dave Mills
28 * This program is free software; you can redistribute it and/or
29 * modify it under the terms of the GNU General Public License
30 * as published by the Free Software Foundation; either version
31 * 2 of the License, or (at your option) any later version.
34 #include <linux/errno.h>
35 #include <linux/export.h>
36 #include <linux/sched.h>
37 #include <linux/kernel.h>
38 #include <linux/param.h>
39 #include <linux/string.h>
40 #include <linux/mm.h>
41 #include <linux/interrupt.h>
42 #include <linux/timex.h>
43 #include <linux/kernel_stat.h>
44 #include <linux/time.h>
45 #include <linux/clockchips.h>
46 #include <linux/init.h>
47 #include <linux/profile.h>
48 #include <linux/cpu.h>
49 #include <linux/security.h>
50 #include <linux/percpu.h>
51 #include <linux/rtc.h>
52 #include <linux/jiffies.h>
53 #include <linux/posix-timers.h>
54 #include <linux/irq.h>
55 #include <linux/delay.h>
56 #include <linux/irq_work.h>
57 #include <asm/trace.h>
59 #include <asm/io.h>
60 #include <asm/processor.h>
61 #include <asm/nvram.h>
62 #include <asm/cache.h>
63 #include <asm/machdep.h>
64 #include <asm/uaccess.h>
65 #include <asm/time.h>
66 #include <asm/prom.h>
67 #include <asm/irq.h>
68 #include <asm/div64.h>
69 #include <asm/smp.h>
70 #include <asm/vdso_datapage.h>
71 #include <asm/firmware.h>
72 #include <asm/cputime.h>
74 /* powerpc clocksource/clockevent code */
76 #include <linux/clockchips.h>
77 #include <linux/timekeeper_internal.h>
79 static cycle_t rtc_read(struct clocksource *);
80 static struct clocksource clocksource_rtc = {
81 .name = "rtc",
82 .rating = 400,
83 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
84 .mask = CLOCKSOURCE_MASK(64),
85 .read = rtc_read,
88 static cycle_t timebase_read(struct clocksource *);
89 static struct clocksource clocksource_timebase = {
90 .name = "timebase",
91 .rating = 400,
92 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
93 .mask = CLOCKSOURCE_MASK(64),
94 .read = timebase_read,
97 #define DECREMENTER_MAX 0x7fffffff
99 static int decrementer_set_next_event(unsigned long evt,
100 struct clock_event_device *dev);
101 static void decrementer_set_mode(enum clock_event_mode mode,
102 struct clock_event_device *dev);
104 struct clock_event_device decrementer_clockevent = {
105 .name = "decrementer",
106 .rating = 200,
107 .irq = 0,
108 .set_next_event = decrementer_set_next_event,
109 .set_mode = decrementer_set_mode,
110 .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP,
112 EXPORT_SYMBOL(decrementer_clockevent);
114 DEFINE_PER_CPU(u64, decrementers_next_tb);
115 static DEFINE_PER_CPU(struct clock_event_device, decrementers);
117 #define XSEC_PER_SEC (1024*1024)
119 #ifdef CONFIG_PPC64
120 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
121 #else
122 /* compute ((xsec << 12) * max) >> 32 */
123 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
124 #endif
126 unsigned long tb_ticks_per_jiffy;
127 unsigned long tb_ticks_per_usec = 100; /* sane default */
128 EXPORT_SYMBOL(tb_ticks_per_usec);
129 unsigned long tb_ticks_per_sec;
130 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
132 DEFINE_SPINLOCK(rtc_lock);
133 EXPORT_SYMBOL_GPL(rtc_lock);
135 static u64 tb_to_ns_scale __read_mostly;
136 static unsigned tb_to_ns_shift __read_mostly;
137 static u64 boot_tb __read_mostly;
139 extern struct timezone sys_tz;
140 static long timezone_offset;
142 unsigned long ppc_proc_freq;
143 EXPORT_SYMBOL_GPL(ppc_proc_freq);
144 unsigned long ppc_tb_freq;
145 EXPORT_SYMBOL_GPL(ppc_tb_freq);
147 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
149 * Factors for converting from cputime_t (timebase ticks) to
150 * jiffies, microseconds, seconds, and clock_t (1/USER_HZ seconds).
151 * These are all stored as 0.64 fixed-point binary fractions.
153 u64 __cputime_jiffies_factor;
154 EXPORT_SYMBOL(__cputime_jiffies_factor);
155 u64 __cputime_usec_factor;
156 EXPORT_SYMBOL(__cputime_usec_factor);
157 u64 __cputime_sec_factor;
158 EXPORT_SYMBOL(__cputime_sec_factor);
159 u64 __cputime_clockt_factor;
160 EXPORT_SYMBOL(__cputime_clockt_factor);
161 DEFINE_PER_CPU(unsigned long, cputime_last_delta);
162 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta);
164 cputime_t cputime_one_jiffy;
166 void (*dtl_consumer)(struct dtl_entry *, u64);
168 static void calc_cputime_factors(void)
170 struct div_result res;
172 div128_by_32(HZ, 0, tb_ticks_per_sec, &res);
173 __cputime_jiffies_factor = res.result_low;
174 div128_by_32(1000000, 0, tb_ticks_per_sec, &res);
175 __cputime_usec_factor = res.result_low;
176 div128_by_32(1, 0, tb_ticks_per_sec, &res);
177 __cputime_sec_factor = res.result_low;
178 div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res);
179 __cputime_clockt_factor = res.result_low;
183 * Read the SPURR on systems that have it, otherwise the PURR,
184 * or if that doesn't exist return the timebase value passed in.
186 static u64 read_spurr(u64 tb)
188 if (cpu_has_feature(CPU_FTR_SPURR))
189 return mfspr(SPRN_SPURR);
190 if (cpu_has_feature(CPU_FTR_PURR))
191 return mfspr(SPRN_PURR);
192 return tb;
195 #ifdef CONFIG_PPC_SPLPAR
198 * Scan the dispatch trace log and count up the stolen time.
199 * Should be called with interrupts disabled.
201 static u64 scan_dispatch_log(u64 stop_tb)
203 u64 i = local_paca->dtl_ridx;
204 struct dtl_entry *dtl = local_paca->dtl_curr;
205 struct dtl_entry *dtl_end = local_paca->dispatch_log_end;
206 struct lppaca *vpa = local_paca->lppaca_ptr;
207 u64 tb_delta;
208 u64 stolen = 0;
209 u64 dtb;
211 if (!dtl)
212 return 0;
214 if (i == be64_to_cpu(vpa->dtl_idx))
215 return 0;
216 while (i < be64_to_cpu(vpa->dtl_idx)) {
217 dtb = be64_to_cpu(dtl->timebase);
218 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) +
219 be32_to_cpu(dtl->ready_to_enqueue_time);
220 barrier();
221 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) {
222 /* buffer has overflowed */
223 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG;
224 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG);
225 continue;
227 if (dtb > stop_tb)
228 break;
229 if (dtl_consumer)
230 dtl_consumer(dtl, i);
231 stolen += tb_delta;
232 ++i;
233 ++dtl;
234 if (dtl == dtl_end)
235 dtl = local_paca->dispatch_log;
237 local_paca->dtl_ridx = i;
238 local_paca->dtl_curr = dtl;
239 return stolen;
243 * Accumulate stolen time by scanning the dispatch trace log.
244 * Called on entry from user mode.
246 void accumulate_stolen_time(void)
248 u64 sst, ust;
250 u8 save_soft_enabled = local_paca->soft_enabled;
252 /* We are called early in the exception entry, before
253 * soft/hard_enabled are sync'ed to the expected state
254 * for the exception. We are hard disabled but the PACA
255 * needs to reflect that so various debug stuff doesn't
256 * complain
258 local_paca->soft_enabled = 0;
260 sst = scan_dispatch_log(local_paca->starttime_user);
261 ust = scan_dispatch_log(local_paca->starttime);
262 local_paca->system_time -= sst;
263 local_paca->user_time -= ust;
264 local_paca->stolen_time += ust + sst;
266 local_paca->soft_enabled = save_soft_enabled;
269 static inline u64 calculate_stolen_time(u64 stop_tb)
271 u64 stolen = 0;
273 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx)) {
274 stolen = scan_dispatch_log(stop_tb);
275 get_paca()->system_time -= stolen;
278 stolen += get_paca()->stolen_time;
279 get_paca()->stolen_time = 0;
280 return stolen;
283 #else /* CONFIG_PPC_SPLPAR */
284 static inline u64 calculate_stolen_time(u64 stop_tb)
286 return 0;
289 #endif /* CONFIG_PPC_SPLPAR */
292 * Account time for a transition between system, hard irq
293 * or soft irq state.
295 static u64 vtime_delta(struct task_struct *tsk,
296 u64 *sys_scaled, u64 *stolen)
298 u64 now, nowscaled, deltascaled;
299 u64 udelta, delta, user_scaled;
301 WARN_ON_ONCE(!irqs_disabled());
303 now = mftb();
304 nowscaled = read_spurr(now);
305 get_paca()->system_time += now - get_paca()->starttime;
306 get_paca()->starttime = now;
307 deltascaled = nowscaled - get_paca()->startspurr;
308 get_paca()->startspurr = nowscaled;
310 *stolen = calculate_stolen_time(now);
312 delta = get_paca()->system_time;
313 get_paca()->system_time = 0;
314 udelta = get_paca()->user_time - get_paca()->utime_sspurr;
315 get_paca()->utime_sspurr = get_paca()->user_time;
318 * Because we don't read the SPURR on every kernel entry/exit,
319 * deltascaled includes both user and system SPURR ticks.
320 * Apportion these ticks to system SPURR ticks and user
321 * SPURR ticks in the same ratio as the system time (delta)
322 * and user time (udelta) values obtained from the timebase
323 * over the same interval. The system ticks get accounted here;
324 * the user ticks get saved up in paca->user_time_scaled to be
325 * used by account_process_tick.
327 *sys_scaled = delta;
328 user_scaled = udelta;
329 if (deltascaled != delta + udelta) {
330 if (udelta) {
331 *sys_scaled = deltascaled * delta / (delta + udelta);
332 user_scaled = deltascaled - *sys_scaled;
333 } else {
334 *sys_scaled = deltascaled;
337 get_paca()->user_time_scaled += user_scaled;
339 return delta;
342 void vtime_account_system(struct task_struct *tsk)
344 u64 delta, sys_scaled, stolen;
346 delta = vtime_delta(tsk, &sys_scaled, &stolen);
347 account_system_time(tsk, 0, delta, sys_scaled);
348 if (stolen)
349 account_steal_time(stolen);
351 EXPORT_SYMBOL_GPL(vtime_account_system);
353 void vtime_account_idle(struct task_struct *tsk)
355 u64 delta, sys_scaled, stolen;
357 delta = vtime_delta(tsk, &sys_scaled, &stolen);
358 account_idle_time(delta + stolen);
362 * Transfer the user time accumulated in the paca
363 * by the exception entry and exit code to the generic
364 * process user time records.
365 * Must be called with interrupts disabled.
366 * Assumes that vtime_account_system/idle() has been called
367 * recently (i.e. since the last entry from usermode) so that
368 * get_paca()->user_time_scaled is up to date.
370 void vtime_account_user(struct task_struct *tsk)
372 cputime_t utime, utimescaled;
374 utime = get_paca()->user_time;
375 utimescaled = get_paca()->user_time_scaled;
376 get_paca()->user_time = 0;
377 get_paca()->user_time_scaled = 0;
378 get_paca()->utime_sspurr = 0;
379 account_user_time(tsk, utime, utimescaled);
382 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
383 #define calc_cputime_factors()
384 #endif
386 void __delay(unsigned long loops)
388 unsigned long start;
389 int diff;
391 if (__USE_RTC()) {
392 start = get_rtcl();
393 do {
394 /* the RTCL register wraps at 1000000000 */
395 diff = get_rtcl() - start;
396 if (diff < 0)
397 diff += 1000000000;
398 } while (diff < loops);
399 } else {
400 start = get_tbl();
401 while (get_tbl() - start < loops)
402 HMT_low();
403 HMT_medium();
406 EXPORT_SYMBOL(__delay);
408 void udelay(unsigned long usecs)
410 __delay(tb_ticks_per_usec * usecs);
412 EXPORT_SYMBOL(udelay);
414 #ifdef CONFIG_SMP
415 unsigned long profile_pc(struct pt_regs *regs)
417 unsigned long pc = instruction_pointer(regs);
419 if (in_lock_functions(pc))
420 return regs->link;
422 return pc;
424 EXPORT_SYMBOL(profile_pc);
425 #endif
427 #ifdef CONFIG_IRQ_WORK
430 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable...
432 #ifdef CONFIG_PPC64
433 static inline unsigned long test_irq_work_pending(void)
435 unsigned long x;
437 asm volatile("lbz %0,%1(13)"
438 : "=r" (x)
439 : "i" (offsetof(struct paca_struct, irq_work_pending)));
440 return x;
443 static inline void set_irq_work_pending_flag(void)
445 asm volatile("stb %0,%1(13)" : :
446 "r" (1),
447 "i" (offsetof(struct paca_struct, irq_work_pending)));
450 static inline void clear_irq_work_pending(void)
452 asm volatile("stb %0,%1(13)" : :
453 "r" (0),
454 "i" (offsetof(struct paca_struct, irq_work_pending)));
457 #else /* 32-bit */
459 DEFINE_PER_CPU(u8, irq_work_pending);
461 #define set_irq_work_pending_flag() __get_cpu_var(irq_work_pending) = 1
462 #define test_irq_work_pending() __get_cpu_var(irq_work_pending)
463 #define clear_irq_work_pending() __get_cpu_var(irq_work_pending) = 0
465 #endif /* 32 vs 64 bit */
467 void arch_irq_work_raise(void)
469 preempt_disable();
470 set_irq_work_pending_flag();
471 set_dec(1);
472 preempt_enable();
475 #else /* CONFIG_IRQ_WORK */
477 #define test_irq_work_pending() 0
478 #define clear_irq_work_pending()
480 #endif /* CONFIG_IRQ_WORK */
482 void __timer_interrupt(void)
484 struct pt_regs *regs = get_irq_regs();
485 u64 *next_tb = &__get_cpu_var(decrementers_next_tb);
486 struct clock_event_device *evt = &__get_cpu_var(decrementers);
487 u64 now;
489 trace_timer_interrupt_entry(regs);
491 if (test_irq_work_pending()) {
492 clear_irq_work_pending();
493 irq_work_run();
496 now = get_tb_or_rtc();
497 if (now >= *next_tb) {
498 *next_tb = ~(u64)0;
499 if (evt->event_handler)
500 evt->event_handler(evt);
501 __get_cpu_var(irq_stat).timer_irqs_event++;
502 } else {
503 now = *next_tb - now;
504 if (now <= DECREMENTER_MAX)
505 set_dec((int)now);
506 /* We may have raced with new irq work */
507 if (test_irq_work_pending())
508 set_dec(1);
509 __get_cpu_var(irq_stat).timer_irqs_others++;
512 #ifdef CONFIG_PPC64
513 /* collect purr register values often, for accurate calculations */
514 if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
515 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
516 cu->current_tb = mfspr(SPRN_PURR);
518 #endif
520 trace_timer_interrupt_exit(regs);
524 * timer_interrupt - gets called when the decrementer overflows,
525 * with interrupts disabled.
527 void timer_interrupt(struct pt_regs * regs)
529 struct pt_regs *old_regs;
530 u64 *next_tb = &__get_cpu_var(decrementers_next_tb);
532 /* Ensure a positive value is written to the decrementer, or else
533 * some CPUs will continue to take decrementer exceptions.
535 set_dec(DECREMENTER_MAX);
537 /* Some implementations of hotplug will get timer interrupts while
538 * offline, just ignore these and we also need to set
539 * decrementers_next_tb as MAX to make sure __check_irq_replay
540 * don't replay timer interrupt when return, otherwise we'll trap
541 * here infinitely :(
543 if (!cpu_online(smp_processor_id())) {
544 *next_tb = ~(u64)0;
545 return;
548 /* Conditionally hard-enable interrupts now that the DEC has been
549 * bumped to its maximum value
551 may_hard_irq_enable();
554 #if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC)
555 if (atomic_read(&ppc_n_lost_interrupts) != 0)
556 do_IRQ(regs);
557 #endif
559 old_regs = set_irq_regs(regs);
560 irq_enter();
562 __timer_interrupt();
563 irq_exit();
564 set_irq_regs(old_regs);
568 * Hypervisor decrementer interrupts shouldn't occur but are sometimes
569 * left pending on exit from a KVM guest. We don't need to do anything
570 * to clear them, as they are edge-triggered.
572 void hdec_interrupt(struct pt_regs *regs)
576 #ifdef CONFIG_SUSPEND
577 static void generic_suspend_disable_irqs(void)
579 /* Disable the decrementer, so that it doesn't interfere
580 * with suspending.
583 set_dec(DECREMENTER_MAX);
584 local_irq_disable();
585 set_dec(DECREMENTER_MAX);
588 static void generic_suspend_enable_irqs(void)
590 local_irq_enable();
593 /* Overrides the weak version in kernel/power/main.c */
594 void arch_suspend_disable_irqs(void)
596 if (ppc_md.suspend_disable_irqs)
597 ppc_md.suspend_disable_irqs();
598 generic_suspend_disable_irqs();
601 /* Overrides the weak version in kernel/power/main.c */
602 void arch_suspend_enable_irqs(void)
604 generic_suspend_enable_irqs();
605 if (ppc_md.suspend_enable_irqs)
606 ppc_md.suspend_enable_irqs();
608 #endif
611 * Scheduler clock - returns current time in nanosec units.
613 * Note: mulhdu(a, b) (multiply high double unsigned) returns
614 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
615 * are 64-bit unsigned numbers.
617 unsigned long long sched_clock(void)
619 if (__USE_RTC())
620 return get_rtc();
621 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
624 static int __init get_freq(char *name, int cells, unsigned long *val)
626 struct device_node *cpu;
627 const __be32 *fp;
628 int found = 0;
630 /* The cpu node should have timebase and clock frequency properties */
631 cpu = of_find_node_by_type(NULL, "cpu");
633 if (cpu) {
634 fp = of_get_property(cpu, name, NULL);
635 if (fp) {
636 found = 1;
637 *val = of_read_ulong(fp, cells);
640 of_node_put(cpu);
643 return found;
646 void start_cpu_decrementer(void)
648 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
649 /* Clear any pending timer interrupts */
650 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS);
652 /* Enable decrementer interrupt */
653 mtspr(SPRN_TCR, TCR_DIE);
654 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */
657 void __init generic_calibrate_decr(void)
659 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */
661 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) &&
662 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) {
664 printk(KERN_ERR "WARNING: Estimating decrementer frequency "
665 "(not found)\n");
668 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */
670 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) &&
671 !get_freq("clock-frequency", 1, &ppc_proc_freq)) {
673 printk(KERN_ERR "WARNING: Estimating processor frequency "
674 "(not found)\n");
678 int update_persistent_clock(struct timespec now)
680 struct rtc_time tm;
682 if (!ppc_md.set_rtc_time)
683 return -ENODEV;
685 to_tm(now.tv_sec + 1 + timezone_offset, &tm);
686 tm.tm_year -= 1900;
687 tm.tm_mon -= 1;
689 return ppc_md.set_rtc_time(&tm);
692 static void __read_persistent_clock(struct timespec *ts)
694 struct rtc_time tm;
695 static int first = 1;
697 ts->tv_nsec = 0;
698 /* XXX this is a litle fragile but will work okay in the short term */
699 if (first) {
700 first = 0;
701 if (ppc_md.time_init)
702 timezone_offset = ppc_md.time_init();
704 /* get_boot_time() isn't guaranteed to be safe to call late */
705 if (ppc_md.get_boot_time) {
706 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset;
707 return;
710 if (!ppc_md.get_rtc_time) {
711 ts->tv_sec = 0;
712 return;
714 ppc_md.get_rtc_time(&tm);
716 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
717 tm.tm_hour, tm.tm_min, tm.tm_sec);
720 void read_persistent_clock(struct timespec *ts)
722 __read_persistent_clock(ts);
724 /* Sanitize it in case real time clock is set below EPOCH */
725 if (ts->tv_sec < 0) {
726 ts->tv_sec = 0;
727 ts->tv_nsec = 0;
732 /* clocksource code */
733 static cycle_t rtc_read(struct clocksource *cs)
735 return (cycle_t)get_rtc();
738 static cycle_t timebase_read(struct clocksource *cs)
740 return (cycle_t)get_tb();
743 void update_vsyscall_old(struct timespec *wall_time, struct timespec *wtm,
744 struct clocksource *clock, u32 mult)
746 u64 new_tb_to_xs, new_stamp_xsec;
747 u32 frac_sec;
749 if (clock != &clocksource_timebase)
750 return;
752 /* Make userspace gettimeofday spin until we're done. */
753 ++vdso_data->tb_update_count;
754 smp_mb();
756 /* 19342813113834067 ~= 2^(20+64) / 1e9 */
757 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift);
758 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC;
759 do_div(new_stamp_xsec, 1000000000);
760 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC;
762 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC);
763 /* this is tv_nsec / 1e9 as a 0.32 fraction */
764 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32;
767 * tb_update_count is used to allow the userspace gettimeofday code
768 * to assure itself that it sees a consistent view of the tb_to_xs and
769 * stamp_xsec variables. It reads the tb_update_count, then reads
770 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
771 * the two values of tb_update_count match and are even then the
772 * tb_to_xs and stamp_xsec values are consistent. If not, then it
773 * loops back and reads them again until this criteria is met.
774 * We expect the caller to have done the first increment of
775 * vdso_data->tb_update_count already.
777 vdso_data->tb_orig_stamp = clock->cycle_last;
778 vdso_data->stamp_xsec = new_stamp_xsec;
779 vdso_data->tb_to_xs = new_tb_to_xs;
780 vdso_data->wtom_clock_sec = wtm->tv_sec;
781 vdso_data->wtom_clock_nsec = wtm->tv_nsec;
782 vdso_data->stamp_xtime = *wall_time;
783 vdso_data->stamp_sec_fraction = frac_sec;
784 smp_wmb();
785 ++(vdso_data->tb_update_count);
788 void update_vsyscall_tz(void)
790 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
791 vdso_data->tz_dsttime = sys_tz.tz_dsttime;
794 static void __init clocksource_init(void)
796 struct clocksource *clock;
798 if (__USE_RTC())
799 clock = &clocksource_rtc;
800 else
801 clock = &clocksource_timebase;
803 if (clocksource_register_hz(clock, tb_ticks_per_sec)) {
804 printk(KERN_ERR "clocksource: %s is already registered\n",
805 clock->name);
806 return;
809 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n",
810 clock->name, clock->mult, clock->shift);
813 static int decrementer_set_next_event(unsigned long evt,
814 struct clock_event_device *dev)
816 __get_cpu_var(decrementers_next_tb) = get_tb_or_rtc() + evt;
817 set_dec(evt);
819 /* We may have raced with new irq work */
820 if (test_irq_work_pending())
821 set_dec(1);
823 return 0;
826 static void decrementer_set_mode(enum clock_event_mode mode,
827 struct clock_event_device *dev)
829 if (mode != CLOCK_EVT_MODE_ONESHOT)
830 decrementer_set_next_event(DECREMENTER_MAX, dev);
833 /* Interrupt handler for the timer broadcast IPI */
834 void tick_broadcast_ipi_handler(void)
836 u64 *next_tb = &__get_cpu_var(decrementers_next_tb);
838 *next_tb = get_tb_or_rtc();
839 __timer_interrupt();
842 static void register_decrementer_clockevent(int cpu)
844 struct clock_event_device *dec = &per_cpu(decrementers, cpu);
846 *dec = decrementer_clockevent;
847 dec->cpumask = cpumask_of(cpu);
849 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n",
850 dec->name, dec->mult, dec->shift, cpu);
852 clockevents_register_device(dec);
855 static void __init init_decrementer_clockevent(void)
857 int cpu = smp_processor_id();
859 clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4);
861 decrementer_clockevent.max_delta_ns =
862 clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent);
863 decrementer_clockevent.min_delta_ns =
864 clockevent_delta2ns(2, &decrementer_clockevent);
866 register_decrementer_clockevent(cpu);
869 void secondary_cpu_time_init(void)
871 /* Start the decrementer on CPUs that have manual control
872 * such as BookE
874 start_cpu_decrementer();
876 /* FIME: Should make unrelatred change to move snapshot_timebase
877 * call here ! */
878 register_decrementer_clockevent(smp_processor_id());
881 /* This function is only called on the boot processor */
882 void __init time_init(void)
884 struct div_result res;
885 u64 scale;
886 unsigned shift;
888 if (__USE_RTC()) {
889 /* 601 processor: dec counts down by 128 every 128ns */
890 ppc_tb_freq = 1000000000;
891 } else {
892 /* Normal PowerPC with timebase register */
893 ppc_md.calibrate_decr();
894 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n",
895 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
896 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n",
897 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
900 tb_ticks_per_jiffy = ppc_tb_freq / HZ;
901 tb_ticks_per_sec = ppc_tb_freq;
902 tb_ticks_per_usec = ppc_tb_freq / 1000000;
903 calc_cputime_factors();
904 setup_cputime_one_jiffy();
907 * Compute scale factor for sched_clock.
908 * The calibrate_decr() function has set tb_ticks_per_sec,
909 * which is the timebase frequency.
910 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
911 * the 128-bit result as a 64.64 fixed-point number.
912 * We then shift that number right until it is less than 1.0,
913 * giving us the scale factor and shift count to use in
914 * sched_clock().
916 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res);
917 scale = res.result_low;
918 for (shift = 0; res.result_high != 0; ++shift) {
919 scale = (scale >> 1) | (res.result_high << 63);
920 res.result_high >>= 1;
922 tb_to_ns_scale = scale;
923 tb_to_ns_shift = shift;
924 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
925 boot_tb = get_tb_or_rtc();
927 /* If platform provided a timezone (pmac), we correct the time */
928 if (timezone_offset) {
929 sys_tz.tz_minuteswest = -timezone_offset / 60;
930 sys_tz.tz_dsttime = 0;
933 vdso_data->tb_update_count = 0;
934 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
936 /* Start the decrementer on CPUs that have manual control
937 * such as BookE
939 start_cpu_decrementer();
941 /* Register the clocksource */
942 clocksource_init();
944 init_decrementer_clockevent();
945 tick_setup_hrtimer_broadcast();
949 #define FEBRUARY 2
950 #define STARTOFTIME 1970
951 #define SECDAY 86400L
952 #define SECYR (SECDAY * 365)
953 #define leapyear(year) ((year) % 4 == 0 && \
954 ((year) % 100 != 0 || (year) % 400 == 0))
955 #define days_in_year(a) (leapyear(a) ? 366 : 365)
956 #define days_in_month(a) (month_days[(a) - 1])
958 static int month_days[12] = {
959 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
963 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
965 void GregorianDay(struct rtc_time * tm)
967 int leapsToDate;
968 int lastYear;
969 int day;
970 int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
972 lastYear = tm->tm_year - 1;
975 * Number of leap corrections to apply up to end of last year
977 leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400;
980 * This year is a leap year if it is divisible by 4 except when it is
981 * divisible by 100 unless it is divisible by 400
983 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
985 day = tm->tm_mon > 2 && leapyear(tm->tm_year);
987 day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] +
988 tm->tm_mday;
990 tm->tm_wday = day % 7;
993 void to_tm(int tim, struct rtc_time * tm)
995 register int i;
996 register long hms, day;
998 day = tim / SECDAY;
999 hms = tim % SECDAY;
1001 /* Hours, minutes, seconds are easy */
1002 tm->tm_hour = hms / 3600;
1003 tm->tm_min = (hms % 3600) / 60;
1004 tm->tm_sec = (hms % 3600) % 60;
1006 /* Number of years in days */
1007 for (i = STARTOFTIME; day >= days_in_year(i); i++)
1008 day -= days_in_year(i);
1009 tm->tm_year = i;
1011 /* Number of months in days left */
1012 if (leapyear(tm->tm_year))
1013 days_in_month(FEBRUARY) = 29;
1014 for (i = 1; day >= days_in_month(i); i++)
1015 day -= days_in_month(i);
1016 days_in_month(FEBRUARY) = 28;
1017 tm->tm_mon = i;
1019 /* Days are what is left over (+1) from all that. */
1020 tm->tm_mday = day + 1;
1023 * Determine the day of week
1025 GregorianDay(tm);
1029 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1030 * result.
1032 void div128_by_32(u64 dividend_high, u64 dividend_low,
1033 unsigned divisor, struct div_result *dr)
1035 unsigned long a, b, c, d;
1036 unsigned long w, x, y, z;
1037 u64 ra, rb, rc;
1039 a = dividend_high >> 32;
1040 b = dividend_high & 0xffffffff;
1041 c = dividend_low >> 32;
1042 d = dividend_low & 0xffffffff;
1044 w = a / divisor;
1045 ra = ((u64)(a - (w * divisor)) << 32) + b;
1047 rb = ((u64) do_div(ra, divisor) << 32) + c;
1048 x = ra;
1050 rc = ((u64) do_div(rb, divisor) << 32) + d;
1051 y = rb;
1053 do_div(rc, divisor);
1054 z = rc;
1056 dr->result_high = ((u64)w << 32) + x;
1057 dr->result_low = ((u64)y << 32) + z;
1061 /* We don't need to calibrate delay, we use the CPU timebase for that */
1062 void calibrate_delay(void)
1064 /* Some generic code (such as spinlock debug) use loops_per_jiffy
1065 * as the number of __delay(1) in a jiffy, so make it so
1067 loops_per_jiffy = tb_ticks_per_jiffy;
1070 static int __init rtc_init(void)
1072 struct platform_device *pdev;
1074 if (!ppc_md.get_rtc_time)
1075 return -ENODEV;
1077 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0);
1079 return PTR_ERR_OR_ZERO(pdev);
1082 module_init(rtc_init);