Loading...
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Common time routines among all ppc machines.
4 *
5 * Written by Cort Dougan (cort@cs.nmt.edu) to merge
6 * Paul Mackerras' version and mine for PReP and Pmac.
7 * MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net).
8 * Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com)
9 *
10 * First round of bugfixes by Gabriel Paubert (paubert@iram.es)
11 * to make clock more stable (2.4.0-test5). The only thing
12 * that this code assumes is that the timebases have been synchronized
13 * by firmware on SMP and are never stopped (never do sleep
14 * on SMP then, nap and doze are OK).
15 *
16 * Speeded up do_gettimeofday by getting rid of references to
17 * xtime (which required locks for consistency). (mikejc@us.ibm.com)
18 *
19 * TODO (not necessarily in this file):
20 * - improve precision and reproducibility of timebase frequency
21 * measurement at boot time.
22 * - for astronomical applications: add a new function to get
23 * non ambiguous timestamps even around leap seconds. This needs
24 * a new timestamp format and a good name.
25 *
26 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
27 * "A Kernel Model for Precision Timekeeping" by Dave Mills
28 */
29
30#include <linux/errno.h>
31#include <linux/export.h>
32#include <linux/sched.h>
33#include <linux/sched/clock.h>
34#include <linux/kernel.h>
35#include <linux/param.h>
36#include <linux/string.h>
37#include <linux/mm.h>
38#include <linux/interrupt.h>
39#include <linux/timex.h>
40#include <linux/kernel_stat.h>
41#include <linux/time.h>
42#include <linux/init.h>
43#include <linux/profile.h>
44#include <linux/cpu.h>
45#include <linux/security.h>
46#include <linux/percpu.h>
47#include <linux/rtc.h>
48#include <linux/jiffies.h>
49#include <linux/posix-timers.h>
50#include <linux/irq.h>
51#include <linux/delay.h>
52#include <linux/irq_work.h>
53#include <linux/of_clk.h>
54#include <linux/suspend.h>
55#include <linux/sched/cputime.h>
56#include <linux/processor.h>
57#include <asm/trace.h>
58
59#include <asm/io.h>
60#include <asm/nvram.h>
61#include <asm/cache.h>
62#include <asm/machdep.h>
63#include <linux/uaccess.h>
64#include <asm/time.h>
65#include <asm/prom.h>
66#include <asm/irq.h>
67#include <asm/div64.h>
68#include <asm/smp.h>
69#include <asm/vdso_datapage.h>
70#include <asm/firmware.h>
71#include <asm/asm-prototypes.h>
72
73/* powerpc clocksource/clockevent code */
74
75#include <linux/clockchips.h>
76#include <linux/timekeeper_internal.h>
77
78static u64 rtc_read(struct clocksource *);
79static struct clocksource clocksource_rtc = {
80 .name = "rtc",
81 .rating = 400,
82 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
83 .mask = CLOCKSOURCE_MASK(64),
84 .read = rtc_read,
85};
86
87static u64 timebase_read(struct clocksource *);
88static struct clocksource clocksource_timebase = {
89 .name = "timebase",
90 .rating = 400,
91 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
92 .mask = CLOCKSOURCE_MASK(64),
93 .read = timebase_read,
94};
95
96#define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF
97u64 decrementer_max = DECREMENTER_DEFAULT_MAX;
98
99static int decrementer_set_next_event(unsigned long evt,
100 struct clock_event_device *dev);
101static int decrementer_shutdown(struct clock_event_device *evt);
102
103struct clock_event_device decrementer_clockevent = {
104 .name = "decrementer",
105 .rating = 200,
106 .irq = 0,
107 .set_next_event = decrementer_set_next_event,
108 .set_state_oneshot_stopped = decrementer_shutdown,
109 .set_state_shutdown = decrementer_shutdown,
110 .tick_resume = decrementer_shutdown,
111 .features = CLOCK_EVT_FEAT_ONESHOT |
112 CLOCK_EVT_FEAT_C3STOP,
113};
114EXPORT_SYMBOL(decrementer_clockevent);
115
116DEFINE_PER_CPU(u64, decrementers_next_tb);
117static DEFINE_PER_CPU(struct clock_event_device, decrementers);
118
119#define XSEC_PER_SEC (1024*1024)
120
121#ifdef CONFIG_PPC64
122#define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
123#else
124/* compute ((xsec << 12) * max) >> 32 */
125#define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
126#endif
127
128unsigned long tb_ticks_per_jiffy;
129unsigned long tb_ticks_per_usec = 100; /* sane default */
130EXPORT_SYMBOL(tb_ticks_per_usec);
131unsigned long tb_ticks_per_sec;
132EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
133
134DEFINE_SPINLOCK(rtc_lock);
135EXPORT_SYMBOL_GPL(rtc_lock);
136
137static u64 tb_to_ns_scale __read_mostly;
138static unsigned tb_to_ns_shift __read_mostly;
139static u64 boot_tb __read_mostly;
140
141extern struct timezone sys_tz;
142static long timezone_offset;
143
144unsigned long ppc_proc_freq;
145EXPORT_SYMBOL_GPL(ppc_proc_freq);
146unsigned long ppc_tb_freq;
147EXPORT_SYMBOL_GPL(ppc_tb_freq);
148
149bool tb_invalid;
150
151#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
152/*
153 * Factor for converting from cputime_t (timebase ticks) to
154 * microseconds. This is stored as 0.64 fixed-point binary fraction.
155 */
156u64 __cputime_usec_factor;
157EXPORT_SYMBOL(__cputime_usec_factor);
158
159#ifdef CONFIG_PPC_SPLPAR
160void (*dtl_consumer)(struct dtl_entry *, u64);
161#endif
162
163static void calc_cputime_factors(void)
164{
165 struct div_result res;
166
167 div128_by_32(1000000, 0, tb_ticks_per_sec, &res);
168 __cputime_usec_factor = res.result_low;
169}
170
171/*
172 * Read the SPURR on systems that have it, otherwise the PURR,
173 * or if that doesn't exist return the timebase value passed in.
174 */
175static inline unsigned long read_spurr(unsigned long tb)
176{
177 if (cpu_has_feature(CPU_FTR_SPURR))
178 return mfspr(SPRN_SPURR);
179 if (cpu_has_feature(CPU_FTR_PURR))
180 return mfspr(SPRN_PURR);
181 return tb;
182}
183
184#ifdef CONFIG_PPC_SPLPAR
185
186#include <asm/dtl.h>
187
188/*
189 * Scan the dispatch trace log and count up the stolen time.
190 * Should be called with interrupts disabled.
191 */
192static u64 scan_dispatch_log(u64 stop_tb)
193{
194 u64 i = local_paca->dtl_ridx;
195 struct dtl_entry *dtl = local_paca->dtl_curr;
196 struct dtl_entry *dtl_end = local_paca->dispatch_log_end;
197 struct lppaca *vpa = local_paca->lppaca_ptr;
198 u64 tb_delta;
199 u64 stolen = 0;
200 u64 dtb;
201
202 if (!dtl)
203 return 0;
204
205 if (i == be64_to_cpu(vpa->dtl_idx))
206 return 0;
207 while (i < be64_to_cpu(vpa->dtl_idx)) {
208 dtb = be64_to_cpu(dtl->timebase);
209 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) +
210 be32_to_cpu(dtl->ready_to_enqueue_time);
211 barrier();
212 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) {
213 /* buffer has overflowed */
214 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG;
215 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG);
216 continue;
217 }
218 if (dtb > stop_tb)
219 break;
220 if (dtl_consumer)
221 dtl_consumer(dtl, i);
222 stolen += tb_delta;
223 ++i;
224 ++dtl;
225 if (dtl == dtl_end)
226 dtl = local_paca->dispatch_log;
227 }
228 local_paca->dtl_ridx = i;
229 local_paca->dtl_curr = dtl;
230 return stolen;
231}
232
233/*
234 * Accumulate stolen time by scanning the dispatch trace log.
235 * Called on entry from user mode.
236 */
237void notrace accumulate_stolen_time(void)
238{
239 u64 sst, ust;
240 unsigned long save_irq_soft_mask = irq_soft_mask_return();
241 struct cpu_accounting_data *acct = &local_paca->accounting;
242
243 /* We are called early in the exception entry, before
244 * soft/hard_enabled are sync'ed to the expected state
245 * for the exception. We are hard disabled but the PACA
246 * needs to reflect that so various debug stuff doesn't
247 * complain
248 */
249 irq_soft_mask_set(IRQS_DISABLED);
250
251 sst = scan_dispatch_log(acct->starttime_user);
252 ust = scan_dispatch_log(acct->starttime);
253 acct->stime -= sst;
254 acct->utime -= ust;
255 acct->steal_time += ust + sst;
256
257 irq_soft_mask_set(save_irq_soft_mask);
258}
259
260static inline u64 calculate_stolen_time(u64 stop_tb)
261{
262 if (!firmware_has_feature(FW_FEATURE_SPLPAR))
263 return 0;
264
265 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx))
266 return scan_dispatch_log(stop_tb);
267
268 return 0;
269}
270
271#else /* CONFIG_PPC_SPLPAR */
272static inline u64 calculate_stolen_time(u64 stop_tb)
273{
274 return 0;
275}
276
277#endif /* CONFIG_PPC_SPLPAR */
278
279/*
280 * Account time for a transition between system, hard irq
281 * or soft irq state.
282 */
283static unsigned long vtime_delta_scaled(struct cpu_accounting_data *acct,
284 unsigned long now, unsigned long stime)
285{
286 unsigned long stime_scaled = 0;
287#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
288 unsigned long nowscaled, deltascaled;
289 unsigned long utime, utime_scaled;
290
291 nowscaled = read_spurr(now);
292 deltascaled = nowscaled - acct->startspurr;
293 acct->startspurr = nowscaled;
294 utime = acct->utime - acct->utime_sspurr;
295 acct->utime_sspurr = acct->utime;
296
297 /*
298 * Because we don't read the SPURR on every kernel entry/exit,
299 * deltascaled includes both user and system SPURR ticks.
300 * Apportion these ticks to system SPURR ticks and user
301 * SPURR ticks in the same ratio as the system time (delta)
302 * and user time (udelta) values obtained from the timebase
303 * over the same interval. The system ticks get accounted here;
304 * the user ticks get saved up in paca->user_time_scaled to be
305 * used by account_process_tick.
306 */
307 stime_scaled = stime;
308 utime_scaled = utime;
309 if (deltascaled != stime + utime) {
310 if (utime) {
311 stime_scaled = deltascaled * stime / (stime + utime);
312 utime_scaled = deltascaled - stime_scaled;
313 } else {
314 stime_scaled = deltascaled;
315 }
316 }
317 acct->utime_scaled += utime_scaled;
318#endif
319
320 return stime_scaled;
321}
322
323static unsigned long vtime_delta(struct task_struct *tsk,
324 unsigned long *stime_scaled,
325 unsigned long *steal_time)
326{
327 unsigned long now, stime;
328 struct cpu_accounting_data *acct = get_accounting(tsk);
329
330 WARN_ON_ONCE(!irqs_disabled());
331
332 now = mftb();
333 stime = now - acct->starttime;
334 acct->starttime = now;
335
336 *stime_scaled = vtime_delta_scaled(acct, now, stime);
337
338 *steal_time = calculate_stolen_time(now);
339
340 return stime;
341}
342
343void vtime_account_kernel(struct task_struct *tsk)
344{
345 unsigned long stime, stime_scaled, steal_time;
346 struct cpu_accounting_data *acct = get_accounting(tsk);
347
348 stime = vtime_delta(tsk, &stime_scaled, &steal_time);
349
350 stime -= min(stime, steal_time);
351 acct->steal_time += steal_time;
352
353 if ((tsk->flags & PF_VCPU) && !irq_count()) {
354 acct->gtime += stime;
355#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
356 acct->utime_scaled += stime_scaled;
357#endif
358 } else {
359 if (hardirq_count())
360 acct->hardirq_time += stime;
361 else if (in_serving_softirq())
362 acct->softirq_time += stime;
363 else
364 acct->stime += stime;
365
366#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
367 acct->stime_scaled += stime_scaled;
368#endif
369 }
370}
371EXPORT_SYMBOL_GPL(vtime_account_kernel);
372
373void vtime_account_idle(struct task_struct *tsk)
374{
375 unsigned long stime, stime_scaled, steal_time;
376 struct cpu_accounting_data *acct = get_accounting(tsk);
377
378 stime = vtime_delta(tsk, &stime_scaled, &steal_time);
379 acct->idle_time += stime + steal_time;
380}
381
382static void vtime_flush_scaled(struct task_struct *tsk,
383 struct cpu_accounting_data *acct)
384{
385#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
386 if (acct->utime_scaled)
387 tsk->utimescaled += cputime_to_nsecs(acct->utime_scaled);
388 if (acct->stime_scaled)
389 tsk->stimescaled += cputime_to_nsecs(acct->stime_scaled);
390
391 acct->utime_scaled = 0;
392 acct->utime_sspurr = 0;
393 acct->stime_scaled = 0;
394#endif
395}
396
397/*
398 * Account the whole cputime accumulated in the paca
399 * Must be called with interrupts disabled.
400 * Assumes that vtime_account_kernel/idle() has been called
401 * recently (i.e. since the last entry from usermode) so that
402 * get_paca()->user_time_scaled is up to date.
403 */
404void vtime_flush(struct task_struct *tsk)
405{
406 struct cpu_accounting_data *acct = get_accounting(tsk);
407
408 if (acct->utime)
409 account_user_time(tsk, cputime_to_nsecs(acct->utime));
410
411 if (acct->gtime)
412 account_guest_time(tsk, cputime_to_nsecs(acct->gtime));
413
414 if (IS_ENABLED(CONFIG_PPC_SPLPAR) && acct->steal_time) {
415 account_steal_time(cputime_to_nsecs(acct->steal_time));
416 acct->steal_time = 0;
417 }
418
419 if (acct->idle_time)
420 account_idle_time(cputime_to_nsecs(acct->idle_time));
421
422 if (acct->stime)
423 account_system_index_time(tsk, cputime_to_nsecs(acct->stime),
424 CPUTIME_SYSTEM);
425
426 if (acct->hardirq_time)
427 account_system_index_time(tsk, cputime_to_nsecs(acct->hardirq_time),
428 CPUTIME_IRQ);
429 if (acct->softirq_time)
430 account_system_index_time(tsk, cputime_to_nsecs(acct->softirq_time),
431 CPUTIME_SOFTIRQ);
432
433 vtime_flush_scaled(tsk, acct);
434
435 acct->utime = 0;
436 acct->gtime = 0;
437 acct->idle_time = 0;
438 acct->stime = 0;
439 acct->hardirq_time = 0;
440 acct->softirq_time = 0;
441}
442
443#else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
444#define calc_cputime_factors()
445#endif
446
447void __delay(unsigned long loops)
448{
449 unsigned long start;
450 int diff;
451
452 spin_begin();
453 if (__USE_RTC()) {
454 start = get_rtcl();
455 do {
456 /* the RTCL register wraps at 1000000000 */
457 diff = get_rtcl() - start;
458 if (diff < 0)
459 diff += 1000000000;
460 spin_cpu_relax();
461 } while (diff < loops);
462 } else if (tb_invalid) {
463 /*
464 * TB is in error state and isn't ticking anymore.
465 * HMI handler was unable to recover from TB error.
466 * Return immediately, so that kernel won't get stuck here.
467 */
468 spin_cpu_relax();
469 } else {
470 start = get_tbl();
471 while (get_tbl() - start < loops)
472 spin_cpu_relax();
473 }
474 spin_end();
475}
476EXPORT_SYMBOL(__delay);
477
478void udelay(unsigned long usecs)
479{
480 __delay(tb_ticks_per_usec * usecs);
481}
482EXPORT_SYMBOL(udelay);
483
484#ifdef CONFIG_SMP
485unsigned long profile_pc(struct pt_regs *regs)
486{
487 unsigned long pc = instruction_pointer(regs);
488
489 if (in_lock_functions(pc))
490 return regs->link;
491
492 return pc;
493}
494EXPORT_SYMBOL(profile_pc);
495#endif
496
497#ifdef CONFIG_IRQ_WORK
498
499/*
500 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable...
501 */
502#ifdef CONFIG_PPC64
503static inline unsigned long test_irq_work_pending(void)
504{
505 unsigned long x;
506
507 asm volatile("lbz %0,%1(13)"
508 : "=r" (x)
509 : "i" (offsetof(struct paca_struct, irq_work_pending)));
510 return x;
511}
512
513static inline void set_irq_work_pending_flag(void)
514{
515 asm volatile("stb %0,%1(13)" : :
516 "r" (1),
517 "i" (offsetof(struct paca_struct, irq_work_pending)));
518}
519
520static inline void clear_irq_work_pending(void)
521{
522 asm volatile("stb %0,%1(13)" : :
523 "r" (0),
524 "i" (offsetof(struct paca_struct, irq_work_pending)));
525}
526
527#else /* 32-bit */
528
529DEFINE_PER_CPU(u8, irq_work_pending);
530
531#define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1)
532#define test_irq_work_pending() __this_cpu_read(irq_work_pending)
533#define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0)
534
535#endif /* 32 vs 64 bit */
536
537void arch_irq_work_raise(void)
538{
539 /*
540 * 64-bit code that uses irq soft-mask can just cause an immediate
541 * interrupt here that gets soft masked, if this is called under
542 * local_irq_disable(). It might be possible to prevent that happening
543 * by noticing interrupts are disabled and setting decrementer pending
544 * to be replayed when irqs are enabled. The problem there is that
545 * tracing can call irq_work_raise, including in code that does low
546 * level manipulations of irq soft-mask state (e.g., trace_hardirqs_on)
547 * which could get tangled up if we're messing with the same state
548 * here.
549 */
550 preempt_disable();
551 set_irq_work_pending_flag();
552 set_dec(1);
553 preempt_enable();
554}
555
556#else /* CONFIG_IRQ_WORK */
557
558#define test_irq_work_pending() 0
559#define clear_irq_work_pending()
560
561#endif /* CONFIG_IRQ_WORK */
562
563/*
564 * timer_interrupt - gets called when the decrementer overflows,
565 * with interrupts disabled.
566 */
567void timer_interrupt(struct pt_regs *regs)
568{
569 struct clock_event_device *evt = this_cpu_ptr(&decrementers);
570 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb);
571 struct pt_regs *old_regs;
572 u64 now;
573
574 /* Some implementations of hotplug will get timer interrupts while
575 * offline, just ignore these and we also need to set
576 * decrementers_next_tb as MAX to make sure __check_irq_replay
577 * don't replay timer interrupt when return, otherwise we'll trap
578 * here infinitely :(
579 */
580 if (unlikely(!cpu_online(smp_processor_id()))) {
581 *next_tb = ~(u64)0;
582 set_dec(decrementer_max);
583 return;
584 }
585
586 /* Ensure a positive value is written to the decrementer, or else
587 * some CPUs will continue to take decrementer exceptions. When the
588 * PPC_WATCHDOG (decrementer based) is configured, keep this at most
589 * 31 bits, which is about 4 seconds on most systems, which gives
590 * the watchdog a chance of catching timer interrupt hard lockups.
591 */
592 if (IS_ENABLED(CONFIG_PPC_WATCHDOG))
593 set_dec(0x7fffffff);
594 else
595 set_dec(decrementer_max);
596
597 /* Conditionally hard-enable interrupts now that the DEC has been
598 * bumped to its maximum value
599 */
600 may_hard_irq_enable();
601
602
603#if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC)
604 if (atomic_read(&ppc_n_lost_interrupts) != 0)
605 do_IRQ(regs);
606#endif
607
608 old_regs = set_irq_regs(regs);
609 irq_enter();
610 trace_timer_interrupt_entry(regs);
611
612 if (test_irq_work_pending()) {
613 clear_irq_work_pending();
614 irq_work_run();
615 }
616
617 now = get_tb_or_rtc();
618 if (now >= *next_tb) {
619 *next_tb = ~(u64)0;
620 if (evt->event_handler)
621 evt->event_handler(evt);
622 __this_cpu_inc(irq_stat.timer_irqs_event);
623 } else {
624 now = *next_tb - now;
625 if (now <= decrementer_max)
626 set_dec(now);
627 /* We may have raced with new irq work */
628 if (test_irq_work_pending())
629 set_dec(1);
630 __this_cpu_inc(irq_stat.timer_irqs_others);
631 }
632
633 trace_timer_interrupt_exit(regs);
634 irq_exit();
635 set_irq_regs(old_regs);
636}
637EXPORT_SYMBOL(timer_interrupt);
638
639#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
640void timer_broadcast_interrupt(void)
641{
642 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb);
643
644 *next_tb = ~(u64)0;
645 tick_receive_broadcast();
646 __this_cpu_inc(irq_stat.broadcast_irqs_event);
647}
648#endif
649
650#ifdef CONFIG_SUSPEND
651static void generic_suspend_disable_irqs(void)
652{
653 /* Disable the decrementer, so that it doesn't interfere
654 * with suspending.
655 */
656
657 set_dec(decrementer_max);
658 local_irq_disable();
659 set_dec(decrementer_max);
660}
661
662static void generic_suspend_enable_irqs(void)
663{
664 local_irq_enable();
665}
666
667/* Overrides the weak version in kernel/power/main.c */
668void arch_suspend_disable_irqs(void)
669{
670 if (ppc_md.suspend_disable_irqs)
671 ppc_md.suspend_disable_irqs();
672 generic_suspend_disable_irqs();
673}
674
675/* Overrides the weak version in kernel/power/main.c */
676void arch_suspend_enable_irqs(void)
677{
678 generic_suspend_enable_irqs();
679 if (ppc_md.suspend_enable_irqs)
680 ppc_md.suspend_enable_irqs();
681}
682#endif
683
684unsigned long long tb_to_ns(unsigned long long ticks)
685{
686 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift;
687}
688EXPORT_SYMBOL_GPL(tb_to_ns);
689
690/*
691 * Scheduler clock - returns current time in nanosec units.
692 *
693 * Note: mulhdu(a, b) (multiply high double unsigned) returns
694 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
695 * are 64-bit unsigned numbers.
696 */
697notrace unsigned long long sched_clock(void)
698{
699 if (__USE_RTC())
700 return get_rtc();
701 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
702}
703
704
705#ifdef CONFIG_PPC_PSERIES
706
707/*
708 * Running clock - attempts to give a view of time passing for a virtualised
709 * kernels.
710 * Uses the VTB register if available otherwise a next best guess.
711 */
712unsigned long long running_clock(void)
713{
714 /*
715 * Don't read the VTB as a host since KVM does not switch in host
716 * timebase into the VTB when it takes a guest off the CPU, reading the
717 * VTB would result in reading 'last switched out' guest VTB.
718 *
719 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it
720 * would be unsafe to rely only on the #ifdef above.
721 */
722 if (firmware_has_feature(FW_FEATURE_LPAR) &&
723 cpu_has_feature(CPU_FTR_ARCH_207S))
724 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
725
726 /*
727 * This is a next best approximation without a VTB.
728 * On a host which is running bare metal there should never be any stolen
729 * time and on a host which doesn't do any virtualisation TB *should* equal
730 * VTB so it makes no difference anyway.
731 */
732 return local_clock() - kcpustat_this_cpu->cpustat[CPUTIME_STEAL];
733}
734#endif
735
736static int __init get_freq(char *name, int cells, unsigned long *val)
737{
738 struct device_node *cpu;
739 const __be32 *fp;
740 int found = 0;
741
742 /* The cpu node should have timebase and clock frequency properties */
743 cpu = of_find_node_by_type(NULL, "cpu");
744
745 if (cpu) {
746 fp = of_get_property(cpu, name, NULL);
747 if (fp) {
748 found = 1;
749 *val = of_read_ulong(fp, cells);
750 }
751
752 of_node_put(cpu);
753 }
754
755 return found;
756}
757
758static void start_cpu_decrementer(void)
759{
760#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
761 unsigned int tcr;
762
763 /* Clear any pending timer interrupts */
764 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS);
765
766 tcr = mfspr(SPRN_TCR);
767 /*
768 * The watchdog may have already been enabled by u-boot. So leave
769 * TRC[WP] (Watchdog Period) alone.
770 */
771 tcr &= TCR_WP_MASK; /* Clear all bits except for TCR[WP] */
772 tcr |= TCR_DIE; /* Enable decrementer */
773 mtspr(SPRN_TCR, tcr);
774#endif
775}
776
777void __init generic_calibrate_decr(void)
778{
779 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */
780
781 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) &&
782 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) {
783
784 printk(KERN_ERR "WARNING: Estimating decrementer frequency "
785 "(not found)\n");
786 }
787
788 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */
789
790 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) &&
791 !get_freq("clock-frequency", 1, &ppc_proc_freq)) {
792
793 printk(KERN_ERR "WARNING: Estimating processor frequency "
794 "(not found)\n");
795 }
796}
797
798int update_persistent_clock64(struct timespec64 now)
799{
800 struct rtc_time tm;
801
802 if (!ppc_md.set_rtc_time)
803 return -ENODEV;
804
805 rtc_time64_to_tm(now.tv_sec + 1 + timezone_offset, &tm);
806
807 return ppc_md.set_rtc_time(&tm);
808}
809
810static void __read_persistent_clock(struct timespec64 *ts)
811{
812 struct rtc_time tm;
813 static int first = 1;
814
815 ts->tv_nsec = 0;
816 /* XXX this is a litle fragile but will work okay in the short term */
817 if (first) {
818 first = 0;
819 if (ppc_md.time_init)
820 timezone_offset = ppc_md.time_init();
821
822 /* get_boot_time() isn't guaranteed to be safe to call late */
823 if (ppc_md.get_boot_time) {
824 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset;
825 return;
826 }
827 }
828 if (!ppc_md.get_rtc_time) {
829 ts->tv_sec = 0;
830 return;
831 }
832 ppc_md.get_rtc_time(&tm);
833
834 ts->tv_sec = rtc_tm_to_time64(&tm);
835}
836
837void read_persistent_clock64(struct timespec64 *ts)
838{
839 __read_persistent_clock(ts);
840
841 /* Sanitize it in case real time clock is set below EPOCH */
842 if (ts->tv_sec < 0) {
843 ts->tv_sec = 0;
844 ts->tv_nsec = 0;
845 }
846
847}
848
849/* clocksource code */
850static notrace u64 rtc_read(struct clocksource *cs)
851{
852 return (u64)get_rtc();
853}
854
855static notrace u64 timebase_read(struct clocksource *cs)
856{
857 return (u64)get_tb();
858}
859
860
861void update_vsyscall(struct timekeeper *tk)
862{
863 struct timespec64 xt;
864 struct clocksource *clock = tk->tkr_mono.clock;
865 u32 mult = tk->tkr_mono.mult;
866 u32 shift = tk->tkr_mono.shift;
867 u64 cycle_last = tk->tkr_mono.cycle_last;
868 u64 new_tb_to_xs, new_stamp_xsec;
869 u64 frac_sec;
870
871 if (clock != &clocksource_timebase)
872 return;
873
874 xt.tv_sec = tk->xtime_sec;
875 xt.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
876
877 /* Make userspace gettimeofday spin until we're done. */
878 ++vdso_data->tb_update_count;
879 smp_mb();
880
881 /*
882 * This computes ((2^20 / 1e9) * mult) >> shift as a
883 * 0.64 fixed-point fraction.
884 * The computation in the else clause below won't overflow
885 * (as long as the timebase frequency is >= 1.049 MHz)
886 * but loses precision because we lose the low bits of the constant
887 * in the shift. Note that 19342813113834067 ~= 2^(20+64) / 1e9.
888 * For a shift of 24 the error is about 0.5e-9, or about 0.5ns
889 * over a second. (Shift values are usually 22, 23 or 24.)
890 * For high frequency clocks such as the 512MHz timebase clock
891 * on POWER[6789], the mult value is small (e.g. 32768000)
892 * and so we can shift the constant by 16 initially
893 * (295147905179 ~= 2^(20+64-16) / 1e9) and then do the
894 * remaining shifts after the multiplication, which gives a
895 * more accurate result (e.g. with mult = 32768000, shift = 24,
896 * the error is only about 1.2e-12, or 0.7ns over 10 minutes).
897 */
898 if (mult <= 62500000 && clock->shift >= 16)
899 new_tb_to_xs = ((u64) mult * 295147905179ULL) >> (clock->shift - 16);
900 else
901 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift);
902
903 /*
904 * Compute the fractional second in units of 2^-32 seconds.
905 * The fractional second is tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift
906 * in nanoseconds, so multiplying that by 2^32 / 1e9 gives
907 * it in units of 2^-32 seconds.
908 * We assume shift <= 32 because clocks_calc_mult_shift()
909 * generates shift values in the range 0 - 32.
910 */
911 frac_sec = tk->tkr_mono.xtime_nsec << (32 - shift);
912 do_div(frac_sec, NSEC_PER_SEC);
913
914 /*
915 * Work out new stamp_xsec value for any legacy users of systemcfg.
916 * stamp_xsec is in units of 2^-20 seconds.
917 */
918 new_stamp_xsec = frac_sec >> 12;
919 new_stamp_xsec += tk->xtime_sec * XSEC_PER_SEC;
920
921 /*
922 * tb_update_count is used to allow the userspace gettimeofday code
923 * to assure itself that it sees a consistent view of the tb_to_xs and
924 * stamp_xsec variables. It reads the tb_update_count, then reads
925 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
926 * the two values of tb_update_count match and are even then the
927 * tb_to_xs and stamp_xsec values are consistent. If not, then it
928 * loops back and reads them again until this criteria is met.
929 */
930 vdso_data->tb_orig_stamp = cycle_last;
931 vdso_data->stamp_xsec = new_stamp_xsec;
932 vdso_data->tb_to_xs = new_tb_to_xs;
933 vdso_data->wtom_clock_sec = tk->wall_to_monotonic.tv_sec;
934 vdso_data->wtom_clock_nsec = tk->wall_to_monotonic.tv_nsec;
935 vdso_data->stamp_xtime_sec = xt.tv_sec;
936 vdso_data->stamp_xtime_nsec = xt.tv_nsec;
937 vdso_data->stamp_sec_fraction = frac_sec;
938 vdso_data->hrtimer_res = hrtimer_resolution;
939 smp_wmb();
940 ++(vdso_data->tb_update_count);
941}
942
943void update_vsyscall_tz(void)
944{
945 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
946 vdso_data->tz_dsttime = sys_tz.tz_dsttime;
947}
948
949static void __init clocksource_init(void)
950{
951 struct clocksource *clock;
952
953 if (__USE_RTC())
954 clock = &clocksource_rtc;
955 else
956 clock = &clocksource_timebase;
957
958 if (clocksource_register_hz(clock, tb_ticks_per_sec)) {
959 printk(KERN_ERR "clocksource: %s is already registered\n",
960 clock->name);
961 return;
962 }
963
964 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n",
965 clock->name, clock->mult, clock->shift);
966}
967
968static int decrementer_set_next_event(unsigned long evt,
969 struct clock_event_device *dev)
970{
971 __this_cpu_write(decrementers_next_tb, get_tb_or_rtc() + evt);
972 set_dec(evt);
973
974 /* We may have raced with new irq work */
975 if (test_irq_work_pending())
976 set_dec(1);
977
978 return 0;
979}
980
981static int decrementer_shutdown(struct clock_event_device *dev)
982{
983 decrementer_set_next_event(decrementer_max, dev);
984 return 0;
985}
986
987static void register_decrementer_clockevent(int cpu)
988{
989 struct clock_event_device *dec = &per_cpu(decrementers, cpu);
990
991 *dec = decrementer_clockevent;
992 dec->cpumask = cpumask_of(cpu);
993
994 clockevents_config_and_register(dec, ppc_tb_freq, 2, decrementer_max);
995
996 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n",
997 dec->name, dec->mult, dec->shift, cpu);
998
999 /* Set values for KVM, see kvm_emulate_dec() */
1000 decrementer_clockevent.mult = dec->mult;
1001 decrementer_clockevent.shift = dec->shift;
1002}
1003
1004static void enable_large_decrementer(void)
1005{
1006 if (!cpu_has_feature(CPU_FTR_ARCH_300))
1007 return;
1008
1009 if (decrementer_max <= DECREMENTER_DEFAULT_MAX)
1010 return;
1011
1012 /*
1013 * If we're running as the hypervisor we need to enable the LD manually
1014 * otherwise firmware should have done it for us.
1015 */
1016 if (cpu_has_feature(CPU_FTR_HVMODE))
1017 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD);
1018}
1019
1020static void __init set_decrementer_max(void)
1021{
1022 struct device_node *cpu;
1023 u32 bits = 32;
1024
1025 /* Prior to ISAv3 the decrementer is always 32 bit */
1026 if (!cpu_has_feature(CPU_FTR_ARCH_300))
1027 return;
1028
1029 cpu = of_find_node_by_type(NULL, "cpu");
1030
1031 if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) {
1032 if (bits > 64 || bits < 32) {
1033 pr_warn("time_init: firmware supplied invalid ibm,dec-bits");
1034 bits = 32;
1035 }
1036
1037 /* calculate the signed maximum given this many bits */
1038 decrementer_max = (1ul << (bits - 1)) - 1;
1039 }
1040
1041 of_node_put(cpu);
1042
1043 pr_info("time_init: %u bit decrementer (max: %llx)\n",
1044 bits, decrementer_max);
1045}
1046
1047static void __init init_decrementer_clockevent(void)
1048{
1049 register_decrementer_clockevent(smp_processor_id());
1050}
1051
1052void secondary_cpu_time_init(void)
1053{
1054 /* Enable and test the large decrementer for this cpu */
1055 enable_large_decrementer();
1056
1057 /* Start the decrementer on CPUs that have manual control
1058 * such as BookE
1059 */
1060 start_cpu_decrementer();
1061
1062 /* FIME: Should make unrelatred change to move snapshot_timebase
1063 * call here ! */
1064 register_decrementer_clockevent(smp_processor_id());
1065}
1066
1067/* This function is only called on the boot processor */
1068void __init time_init(void)
1069{
1070 struct div_result res;
1071 u64 scale;
1072 unsigned shift;
1073
1074 if (__USE_RTC()) {
1075 /* 601 processor: dec counts down by 128 every 128ns */
1076 ppc_tb_freq = 1000000000;
1077 } else {
1078 /* Normal PowerPC with timebase register */
1079 ppc_md.calibrate_decr();
1080 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n",
1081 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
1082 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n",
1083 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
1084 }
1085
1086 tb_ticks_per_jiffy = ppc_tb_freq / HZ;
1087 tb_ticks_per_sec = ppc_tb_freq;
1088 tb_ticks_per_usec = ppc_tb_freq / 1000000;
1089 calc_cputime_factors();
1090
1091 /*
1092 * Compute scale factor for sched_clock.
1093 * The calibrate_decr() function has set tb_ticks_per_sec,
1094 * which is the timebase frequency.
1095 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
1096 * the 128-bit result as a 64.64 fixed-point number.
1097 * We then shift that number right until it is less than 1.0,
1098 * giving us the scale factor and shift count to use in
1099 * sched_clock().
1100 */
1101 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res);
1102 scale = res.result_low;
1103 for (shift = 0; res.result_high != 0; ++shift) {
1104 scale = (scale >> 1) | (res.result_high << 63);
1105 res.result_high >>= 1;
1106 }
1107 tb_to_ns_scale = scale;
1108 tb_to_ns_shift = shift;
1109 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
1110 boot_tb = get_tb_or_rtc();
1111
1112 /* If platform provided a timezone (pmac), we correct the time */
1113 if (timezone_offset) {
1114 sys_tz.tz_minuteswest = -timezone_offset / 60;
1115 sys_tz.tz_dsttime = 0;
1116 }
1117
1118 vdso_data->tb_update_count = 0;
1119 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
1120
1121 /* initialise and enable the large decrementer (if we have one) */
1122 set_decrementer_max();
1123 enable_large_decrementer();
1124
1125 /* Start the decrementer on CPUs that have manual control
1126 * such as BookE
1127 */
1128 start_cpu_decrementer();
1129
1130 /* Register the clocksource */
1131 clocksource_init();
1132
1133 init_decrementer_clockevent();
1134 tick_setup_hrtimer_broadcast();
1135
1136 of_clk_init(NULL);
1137}
1138
1139/*
1140 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1141 * result.
1142 */
1143void div128_by_32(u64 dividend_high, u64 dividend_low,
1144 unsigned divisor, struct div_result *dr)
1145{
1146 unsigned long a, b, c, d;
1147 unsigned long w, x, y, z;
1148 u64 ra, rb, rc;
1149
1150 a = dividend_high >> 32;
1151 b = dividend_high & 0xffffffff;
1152 c = dividend_low >> 32;
1153 d = dividend_low & 0xffffffff;
1154
1155 w = a / divisor;
1156 ra = ((u64)(a - (w * divisor)) << 32) + b;
1157
1158 rb = ((u64) do_div(ra, divisor) << 32) + c;
1159 x = ra;
1160
1161 rc = ((u64) do_div(rb, divisor) << 32) + d;
1162 y = rb;
1163
1164 do_div(rc, divisor);
1165 z = rc;
1166
1167 dr->result_high = ((u64)w << 32) + x;
1168 dr->result_low = ((u64)y << 32) + z;
1169
1170}
1171
1172/* We don't need to calibrate delay, we use the CPU timebase for that */
1173void calibrate_delay(void)
1174{
1175 /* Some generic code (such as spinlock debug) use loops_per_jiffy
1176 * as the number of __delay(1) in a jiffy, so make it so
1177 */
1178 loops_per_jiffy = tb_ticks_per_jiffy;
1179}
1180
1181#if IS_ENABLED(CONFIG_RTC_DRV_GENERIC)
1182static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
1183{
1184 ppc_md.get_rtc_time(tm);
1185 return 0;
1186}
1187
1188static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)
1189{
1190 if (!ppc_md.set_rtc_time)
1191 return -EOPNOTSUPP;
1192
1193 if (ppc_md.set_rtc_time(tm) < 0)
1194 return -EOPNOTSUPP;
1195
1196 return 0;
1197}
1198
1199static const struct rtc_class_ops rtc_generic_ops = {
1200 .read_time = rtc_generic_get_time,
1201 .set_time = rtc_generic_set_time,
1202};
1203
1204static int __init rtc_init(void)
1205{
1206 struct platform_device *pdev;
1207
1208 if (!ppc_md.get_rtc_time)
1209 return -ENODEV;
1210
1211 pdev = platform_device_register_data(NULL, "rtc-generic", -1,
1212 &rtc_generic_ops,
1213 sizeof(rtc_generic_ops));
1214
1215 return PTR_ERR_OR_ZERO(pdev);
1216}
1217
1218device_initcall(rtc_init);
1219#endif
1/*
2 * Common time routines among all ppc machines.
3 *
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)
8 *
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).
14 *
15 * Speeded up do_gettimeofday by getting rid of references to
16 * xtime (which required locks for consistency). (mikejc@us.ibm.com)
17 *
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.
24 *
25 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
26 * "A Kernel Model for Precision Timekeeping" by Dave Mills
27 *
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.
32 */
33
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/init.h>
46#include <linux/profile.h>
47#include <linux/cpu.h>
48#include <linux/security.h>
49#include <linux/percpu.h>
50#include <linux/rtc.h>
51#include <linux/jiffies.h>
52#include <linux/posix-timers.h>
53#include <linux/irq.h>
54#include <linux/delay.h>
55#include <linux/irq_work.h>
56#include <asm/trace.h>
57
58#include <asm/io.h>
59#include <asm/processor.h>
60#include <asm/nvram.h>
61#include <asm/cache.h>
62#include <asm/machdep.h>
63#include <asm/uaccess.h>
64#include <asm/time.h>
65#include <asm/prom.h>
66#include <asm/irq.h>
67#include <asm/div64.h>
68#include <asm/smp.h>
69#include <asm/vdso_datapage.h>
70#include <asm/firmware.h>
71#include <asm/cputime.h>
72
73/* powerpc clocksource/clockevent code */
74
75#include <linux/clockchips.h>
76#include <linux/clocksource.h>
77
78static cycle_t rtc_read(struct clocksource *);
79static struct clocksource clocksource_rtc = {
80 .name = "rtc",
81 .rating = 400,
82 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
83 .mask = CLOCKSOURCE_MASK(64),
84 .read = rtc_read,
85};
86
87static cycle_t timebase_read(struct clocksource *);
88static struct clocksource clocksource_timebase = {
89 .name = "timebase",
90 .rating = 400,
91 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
92 .mask = CLOCKSOURCE_MASK(64),
93 .read = timebase_read,
94};
95
96#define DECREMENTER_MAX 0x7fffffff
97
98static int decrementer_set_next_event(unsigned long evt,
99 struct clock_event_device *dev);
100static void decrementer_set_mode(enum clock_event_mode mode,
101 struct clock_event_device *dev);
102
103struct clock_event_device decrementer_clockevent = {
104 .name = "decrementer",
105 .rating = 200,
106 .irq = 0,
107 .set_next_event = decrementer_set_next_event,
108 .set_mode = decrementer_set_mode,
109 .features = CLOCK_EVT_FEAT_ONESHOT,
110};
111EXPORT_SYMBOL(decrementer_clockevent);
112
113DEFINE_PER_CPU(u64, decrementers_next_tb);
114static DEFINE_PER_CPU(struct clock_event_device, decrementers);
115
116#define XSEC_PER_SEC (1024*1024)
117
118#ifdef CONFIG_PPC64
119#define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
120#else
121/* compute ((xsec << 12) * max) >> 32 */
122#define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
123#endif
124
125unsigned long tb_ticks_per_jiffy;
126unsigned long tb_ticks_per_usec = 100; /* sane default */
127EXPORT_SYMBOL(tb_ticks_per_usec);
128unsigned long tb_ticks_per_sec;
129EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
130
131DEFINE_SPINLOCK(rtc_lock);
132EXPORT_SYMBOL_GPL(rtc_lock);
133
134static u64 tb_to_ns_scale __read_mostly;
135static unsigned tb_to_ns_shift __read_mostly;
136static u64 boot_tb __read_mostly;
137
138extern struct timezone sys_tz;
139static long timezone_offset;
140
141unsigned long ppc_proc_freq;
142EXPORT_SYMBOL_GPL(ppc_proc_freq);
143unsigned long ppc_tb_freq;
144EXPORT_SYMBOL_GPL(ppc_tb_freq);
145
146#ifdef CONFIG_VIRT_CPU_ACCOUNTING
147/*
148 * Factors for converting from cputime_t (timebase ticks) to
149 * jiffies, microseconds, seconds, and clock_t (1/USER_HZ seconds).
150 * These are all stored as 0.64 fixed-point binary fractions.
151 */
152u64 __cputime_jiffies_factor;
153EXPORT_SYMBOL(__cputime_jiffies_factor);
154u64 __cputime_usec_factor;
155EXPORT_SYMBOL(__cputime_usec_factor);
156u64 __cputime_sec_factor;
157EXPORT_SYMBOL(__cputime_sec_factor);
158u64 __cputime_clockt_factor;
159EXPORT_SYMBOL(__cputime_clockt_factor);
160DEFINE_PER_CPU(unsigned long, cputime_last_delta);
161DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta);
162
163cputime_t cputime_one_jiffy;
164
165void (*dtl_consumer)(struct dtl_entry *, u64);
166
167static void calc_cputime_factors(void)
168{
169 struct div_result res;
170
171 div128_by_32(HZ, 0, tb_ticks_per_sec, &res);
172 __cputime_jiffies_factor = res.result_low;
173 div128_by_32(1000000, 0, tb_ticks_per_sec, &res);
174 __cputime_usec_factor = res.result_low;
175 div128_by_32(1, 0, tb_ticks_per_sec, &res);
176 __cputime_sec_factor = res.result_low;
177 div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res);
178 __cputime_clockt_factor = res.result_low;
179}
180
181/*
182 * Read the SPURR on systems that have it, otherwise the PURR,
183 * or if that doesn't exist return the timebase value passed in.
184 */
185static u64 read_spurr(u64 tb)
186{
187 if (cpu_has_feature(CPU_FTR_SPURR))
188 return mfspr(SPRN_SPURR);
189 if (cpu_has_feature(CPU_FTR_PURR))
190 return mfspr(SPRN_PURR);
191 return tb;
192}
193
194#ifdef CONFIG_PPC_SPLPAR
195
196/*
197 * Scan the dispatch trace log and count up the stolen time.
198 * Should be called with interrupts disabled.
199 */
200static u64 scan_dispatch_log(u64 stop_tb)
201{
202 u64 i = local_paca->dtl_ridx;
203 struct dtl_entry *dtl = local_paca->dtl_curr;
204 struct dtl_entry *dtl_end = local_paca->dispatch_log_end;
205 struct lppaca *vpa = local_paca->lppaca_ptr;
206 u64 tb_delta;
207 u64 stolen = 0;
208 u64 dtb;
209
210 if (!dtl)
211 return 0;
212
213 if (i == vpa->dtl_idx)
214 return 0;
215 while (i < vpa->dtl_idx) {
216 if (dtl_consumer)
217 dtl_consumer(dtl, i);
218 dtb = dtl->timebase;
219 tb_delta = dtl->enqueue_to_dispatch_time +
220 dtl->ready_to_enqueue_time;
221 barrier();
222 if (i + N_DISPATCH_LOG < vpa->dtl_idx) {
223 /* buffer has overflowed */
224 i = vpa->dtl_idx - N_DISPATCH_LOG;
225 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG);
226 continue;
227 }
228 if (dtb > stop_tb)
229 break;
230 stolen += tb_delta;
231 ++i;
232 ++dtl;
233 if (dtl == dtl_end)
234 dtl = local_paca->dispatch_log;
235 }
236 local_paca->dtl_ridx = i;
237 local_paca->dtl_curr = dtl;
238 return stolen;
239}
240
241/*
242 * Accumulate stolen time by scanning the dispatch trace log.
243 * Called on entry from user mode.
244 */
245void accumulate_stolen_time(void)
246{
247 u64 sst, ust;
248
249 u8 save_soft_enabled = local_paca->soft_enabled;
250
251 /* We are called early in the exception entry, before
252 * soft/hard_enabled are sync'ed to the expected state
253 * for the exception. We are hard disabled but the PACA
254 * needs to reflect that so various debug stuff doesn't
255 * complain
256 */
257 local_paca->soft_enabled = 0;
258
259 sst = scan_dispatch_log(local_paca->starttime_user);
260 ust = scan_dispatch_log(local_paca->starttime);
261 local_paca->system_time -= sst;
262 local_paca->user_time -= ust;
263 local_paca->stolen_time += ust + sst;
264
265 local_paca->soft_enabled = save_soft_enabled;
266}
267
268static inline u64 calculate_stolen_time(u64 stop_tb)
269{
270 u64 stolen = 0;
271
272 if (get_paca()->dtl_ridx != get_paca()->lppaca_ptr->dtl_idx) {
273 stolen = scan_dispatch_log(stop_tb);
274 get_paca()->system_time -= stolen;
275 }
276
277 stolen += get_paca()->stolen_time;
278 get_paca()->stolen_time = 0;
279 return stolen;
280}
281
282#else /* CONFIG_PPC_SPLPAR */
283static inline u64 calculate_stolen_time(u64 stop_tb)
284{
285 return 0;
286}
287
288#endif /* CONFIG_PPC_SPLPAR */
289
290/*
291 * Account time for a transition between system, hard irq
292 * or soft irq state.
293 */
294void account_system_vtime(struct task_struct *tsk)
295{
296 u64 now, nowscaled, delta, deltascaled;
297 unsigned long flags;
298 u64 stolen, udelta, sys_scaled, user_scaled;
299
300 local_irq_save(flags);
301 now = mftb();
302 nowscaled = read_spurr(now);
303 get_paca()->system_time += now - get_paca()->starttime;
304 get_paca()->starttime = now;
305 deltascaled = nowscaled - get_paca()->startspurr;
306 get_paca()->startspurr = nowscaled;
307
308 stolen = calculate_stolen_time(now);
309
310 delta = get_paca()->system_time;
311 get_paca()->system_time = 0;
312 udelta = get_paca()->user_time - get_paca()->utime_sspurr;
313 get_paca()->utime_sspurr = get_paca()->user_time;
314
315 /*
316 * Because we don't read the SPURR on every kernel entry/exit,
317 * deltascaled includes both user and system SPURR ticks.
318 * Apportion these ticks to system SPURR ticks and user
319 * SPURR ticks in the same ratio as the system time (delta)
320 * and user time (udelta) values obtained from the timebase
321 * over the same interval. The system ticks get accounted here;
322 * the user ticks get saved up in paca->user_time_scaled to be
323 * used by account_process_tick.
324 */
325 sys_scaled = delta;
326 user_scaled = udelta;
327 if (deltascaled != delta + udelta) {
328 if (udelta) {
329 sys_scaled = deltascaled * delta / (delta + udelta);
330 user_scaled = deltascaled - sys_scaled;
331 } else {
332 sys_scaled = deltascaled;
333 }
334 }
335 get_paca()->user_time_scaled += user_scaled;
336
337 if (in_interrupt() || idle_task(smp_processor_id()) != tsk) {
338 account_system_time(tsk, 0, delta, sys_scaled);
339 if (stolen)
340 account_steal_time(stolen);
341 } else {
342 account_idle_time(delta + stolen);
343 }
344 local_irq_restore(flags);
345}
346EXPORT_SYMBOL_GPL(account_system_vtime);
347
348/*
349 * Transfer the user and system times accumulated in the paca
350 * by the exception entry and exit code to the generic process
351 * user and system time records.
352 * Must be called with interrupts disabled.
353 * Assumes that account_system_vtime() has been called recently
354 * (i.e. since the last entry from usermode) so that
355 * get_paca()->user_time_scaled is up to date.
356 */
357void account_process_tick(struct task_struct *tsk, int user_tick)
358{
359 cputime_t utime, utimescaled;
360
361 utime = get_paca()->user_time;
362 utimescaled = get_paca()->user_time_scaled;
363 get_paca()->user_time = 0;
364 get_paca()->user_time_scaled = 0;
365 get_paca()->utime_sspurr = 0;
366 account_user_time(tsk, utime, utimescaled);
367}
368
369#else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
370#define calc_cputime_factors()
371#endif
372
373void __delay(unsigned long loops)
374{
375 unsigned long start;
376 int diff;
377
378 if (__USE_RTC()) {
379 start = get_rtcl();
380 do {
381 /* the RTCL register wraps at 1000000000 */
382 diff = get_rtcl() - start;
383 if (diff < 0)
384 diff += 1000000000;
385 } while (diff < loops);
386 } else {
387 start = get_tbl();
388 while (get_tbl() - start < loops)
389 HMT_low();
390 HMT_medium();
391 }
392}
393EXPORT_SYMBOL(__delay);
394
395void udelay(unsigned long usecs)
396{
397 __delay(tb_ticks_per_usec * usecs);
398}
399EXPORT_SYMBOL(udelay);
400
401#ifdef CONFIG_SMP
402unsigned long profile_pc(struct pt_regs *regs)
403{
404 unsigned long pc = instruction_pointer(regs);
405
406 if (in_lock_functions(pc))
407 return regs->link;
408
409 return pc;
410}
411EXPORT_SYMBOL(profile_pc);
412#endif
413
414#ifdef CONFIG_IRQ_WORK
415
416/*
417 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable...
418 */
419#ifdef CONFIG_PPC64
420static inline unsigned long test_irq_work_pending(void)
421{
422 unsigned long x;
423
424 asm volatile("lbz %0,%1(13)"
425 : "=r" (x)
426 : "i" (offsetof(struct paca_struct, irq_work_pending)));
427 return x;
428}
429
430static inline void set_irq_work_pending_flag(void)
431{
432 asm volatile("stb %0,%1(13)" : :
433 "r" (1),
434 "i" (offsetof(struct paca_struct, irq_work_pending)));
435}
436
437static inline void clear_irq_work_pending(void)
438{
439 asm volatile("stb %0,%1(13)" : :
440 "r" (0),
441 "i" (offsetof(struct paca_struct, irq_work_pending)));
442}
443
444#else /* 32-bit */
445
446DEFINE_PER_CPU(u8, irq_work_pending);
447
448#define set_irq_work_pending_flag() __get_cpu_var(irq_work_pending) = 1
449#define test_irq_work_pending() __get_cpu_var(irq_work_pending)
450#define clear_irq_work_pending() __get_cpu_var(irq_work_pending) = 0
451
452#endif /* 32 vs 64 bit */
453
454void arch_irq_work_raise(void)
455{
456 preempt_disable();
457 set_irq_work_pending_flag();
458 set_dec(1);
459 preempt_enable();
460}
461
462#else /* CONFIG_IRQ_WORK */
463
464#define test_irq_work_pending() 0
465#define clear_irq_work_pending()
466
467#endif /* CONFIG_IRQ_WORK */
468
469/*
470 * timer_interrupt - gets called when the decrementer overflows,
471 * with interrupts disabled.
472 */
473void timer_interrupt(struct pt_regs * regs)
474{
475 struct pt_regs *old_regs;
476 u64 *next_tb = &__get_cpu_var(decrementers_next_tb);
477 struct clock_event_device *evt = &__get_cpu_var(decrementers);
478 u64 now;
479
480 /* Ensure a positive value is written to the decrementer, or else
481 * some CPUs will continue to take decrementer exceptions.
482 */
483 set_dec(DECREMENTER_MAX);
484
485 /* Some implementations of hotplug will get timer interrupts while
486 * offline, just ignore these
487 */
488 if (!cpu_online(smp_processor_id()))
489 return;
490
491 /* Conditionally hard-enable interrupts now that the DEC has been
492 * bumped to its maximum value
493 */
494 may_hard_irq_enable();
495
496 trace_timer_interrupt_entry(regs);
497
498 __get_cpu_var(irq_stat).timer_irqs++;
499
500#if defined(CONFIG_PPC32) && defined(CONFIG_PMAC)
501 if (atomic_read(&ppc_n_lost_interrupts) != 0)
502 do_IRQ(regs);
503#endif
504
505 old_regs = set_irq_regs(regs);
506 irq_enter();
507
508 if (test_irq_work_pending()) {
509 clear_irq_work_pending();
510 irq_work_run();
511 }
512
513 now = get_tb_or_rtc();
514 if (now >= *next_tb) {
515 *next_tb = ~(u64)0;
516 if (evt->event_handler)
517 evt->event_handler(evt);
518 } else {
519 now = *next_tb - now;
520 if (now <= DECREMENTER_MAX)
521 set_dec((int)now);
522 }
523
524#ifdef CONFIG_PPC64
525 /* collect purr register values often, for accurate calculations */
526 if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
527 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
528 cu->current_tb = mfspr(SPRN_PURR);
529 }
530#endif
531
532 irq_exit();
533 set_irq_regs(old_regs);
534
535 trace_timer_interrupt_exit(regs);
536}
537
538#ifdef CONFIG_SUSPEND
539static void generic_suspend_disable_irqs(void)
540{
541 /* Disable the decrementer, so that it doesn't interfere
542 * with suspending.
543 */
544
545 set_dec(DECREMENTER_MAX);
546 local_irq_disable();
547 set_dec(DECREMENTER_MAX);
548}
549
550static void generic_suspend_enable_irqs(void)
551{
552 local_irq_enable();
553}
554
555/* Overrides the weak version in kernel/power/main.c */
556void arch_suspend_disable_irqs(void)
557{
558 if (ppc_md.suspend_disable_irqs)
559 ppc_md.suspend_disable_irqs();
560 generic_suspend_disable_irqs();
561}
562
563/* Overrides the weak version in kernel/power/main.c */
564void arch_suspend_enable_irqs(void)
565{
566 generic_suspend_enable_irqs();
567 if (ppc_md.suspend_enable_irqs)
568 ppc_md.suspend_enable_irqs();
569}
570#endif
571
572/*
573 * Scheduler clock - returns current time in nanosec units.
574 *
575 * Note: mulhdu(a, b) (multiply high double unsigned) returns
576 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
577 * are 64-bit unsigned numbers.
578 */
579unsigned long long sched_clock(void)
580{
581 if (__USE_RTC())
582 return get_rtc();
583 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
584}
585
586static int __init get_freq(char *name, int cells, unsigned long *val)
587{
588 struct device_node *cpu;
589 const unsigned int *fp;
590 int found = 0;
591
592 /* The cpu node should have timebase and clock frequency properties */
593 cpu = of_find_node_by_type(NULL, "cpu");
594
595 if (cpu) {
596 fp = of_get_property(cpu, name, NULL);
597 if (fp) {
598 found = 1;
599 *val = of_read_ulong(fp, cells);
600 }
601
602 of_node_put(cpu);
603 }
604
605 return found;
606}
607
608/* should become __cpuinit when secondary_cpu_time_init also is */
609void start_cpu_decrementer(void)
610{
611#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
612 /* Clear any pending timer interrupts */
613 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS);
614
615 /* Enable decrementer interrupt */
616 mtspr(SPRN_TCR, TCR_DIE);
617#endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */
618}
619
620void __init generic_calibrate_decr(void)
621{
622 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */
623
624 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) &&
625 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) {
626
627 printk(KERN_ERR "WARNING: Estimating decrementer frequency "
628 "(not found)\n");
629 }
630
631 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */
632
633 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) &&
634 !get_freq("clock-frequency", 1, &ppc_proc_freq)) {
635
636 printk(KERN_ERR "WARNING: Estimating processor frequency "
637 "(not found)\n");
638 }
639}
640
641int update_persistent_clock(struct timespec now)
642{
643 struct rtc_time tm;
644
645 if (!ppc_md.set_rtc_time)
646 return 0;
647
648 to_tm(now.tv_sec + 1 + timezone_offset, &tm);
649 tm.tm_year -= 1900;
650 tm.tm_mon -= 1;
651
652 return ppc_md.set_rtc_time(&tm);
653}
654
655static void __read_persistent_clock(struct timespec *ts)
656{
657 struct rtc_time tm;
658 static int first = 1;
659
660 ts->tv_nsec = 0;
661 /* XXX this is a litle fragile but will work okay in the short term */
662 if (first) {
663 first = 0;
664 if (ppc_md.time_init)
665 timezone_offset = ppc_md.time_init();
666
667 /* get_boot_time() isn't guaranteed to be safe to call late */
668 if (ppc_md.get_boot_time) {
669 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset;
670 return;
671 }
672 }
673 if (!ppc_md.get_rtc_time) {
674 ts->tv_sec = 0;
675 return;
676 }
677 ppc_md.get_rtc_time(&tm);
678
679 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
680 tm.tm_hour, tm.tm_min, tm.tm_sec);
681}
682
683void read_persistent_clock(struct timespec *ts)
684{
685 __read_persistent_clock(ts);
686
687 /* Sanitize it in case real time clock is set below EPOCH */
688 if (ts->tv_sec < 0) {
689 ts->tv_sec = 0;
690 ts->tv_nsec = 0;
691 }
692
693}
694
695/* clocksource code */
696static cycle_t rtc_read(struct clocksource *cs)
697{
698 return (cycle_t)get_rtc();
699}
700
701static cycle_t timebase_read(struct clocksource *cs)
702{
703 return (cycle_t)get_tb();
704}
705
706void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
707 struct clocksource *clock, u32 mult)
708{
709 u64 new_tb_to_xs, new_stamp_xsec;
710 u32 frac_sec;
711
712 if (clock != &clocksource_timebase)
713 return;
714
715 /* Make userspace gettimeofday spin until we're done. */
716 ++vdso_data->tb_update_count;
717 smp_mb();
718
719 /* 19342813113834067 ~= 2^(20+64) / 1e9 */
720 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift);
721 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC;
722 do_div(new_stamp_xsec, 1000000000);
723 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC;
724
725 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC);
726 /* this is tv_nsec / 1e9 as a 0.32 fraction */
727 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32;
728
729 /*
730 * tb_update_count is used to allow the userspace gettimeofday code
731 * to assure itself that it sees a consistent view of the tb_to_xs and
732 * stamp_xsec variables. It reads the tb_update_count, then reads
733 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
734 * the two values of tb_update_count match and are even then the
735 * tb_to_xs and stamp_xsec values are consistent. If not, then it
736 * loops back and reads them again until this criteria is met.
737 * We expect the caller to have done the first increment of
738 * vdso_data->tb_update_count already.
739 */
740 vdso_data->tb_orig_stamp = clock->cycle_last;
741 vdso_data->stamp_xsec = new_stamp_xsec;
742 vdso_data->tb_to_xs = new_tb_to_xs;
743 vdso_data->wtom_clock_sec = wtm->tv_sec;
744 vdso_data->wtom_clock_nsec = wtm->tv_nsec;
745 vdso_data->stamp_xtime = *wall_time;
746 vdso_data->stamp_sec_fraction = frac_sec;
747 smp_wmb();
748 ++(vdso_data->tb_update_count);
749}
750
751void update_vsyscall_tz(void)
752{
753 /* Make userspace gettimeofday spin until we're done. */
754 ++vdso_data->tb_update_count;
755 smp_mb();
756 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
757 vdso_data->tz_dsttime = sys_tz.tz_dsttime;
758 smp_mb();
759 ++vdso_data->tb_update_count;
760}
761
762static void __init clocksource_init(void)
763{
764 struct clocksource *clock;
765
766 if (__USE_RTC())
767 clock = &clocksource_rtc;
768 else
769 clock = &clocksource_timebase;
770
771 if (clocksource_register_hz(clock, tb_ticks_per_sec)) {
772 printk(KERN_ERR "clocksource: %s is already registered\n",
773 clock->name);
774 return;
775 }
776
777 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n",
778 clock->name, clock->mult, clock->shift);
779}
780
781static int decrementer_set_next_event(unsigned long evt,
782 struct clock_event_device *dev)
783{
784 __get_cpu_var(decrementers_next_tb) = get_tb_or_rtc() + evt;
785 set_dec(evt);
786 return 0;
787}
788
789static void decrementer_set_mode(enum clock_event_mode mode,
790 struct clock_event_device *dev)
791{
792 if (mode != CLOCK_EVT_MODE_ONESHOT)
793 decrementer_set_next_event(DECREMENTER_MAX, dev);
794}
795
796static void register_decrementer_clockevent(int cpu)
797{
798 struct clock_event_device *dec = &per_cpu(decrementers, cpu);
799
800 *dec = decrementer_clockevent;
801 dec->cpumask = cpumask_of(cpu);
802
803 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n",
804 dec->name, dec->mult, dec->shift, cpu);
805
806 clockevents_register_device(dec);
807}
808
809static void __init init_decrementer_clockevent(void)
810{
811 int cpu = smp_processor_id();
812
813 clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4);
814
815 decrementer_clockevent.max_delta_ns =
816 clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent);
817 decrementer_clockevent.min_delta_ns =
818 clockevent_delta2ns(2, &decrementer_clockevent);
819
820 register_decrementer_clockevent(cpu);
821}
822
823void secondary_cpu_time_init(void)
824{
825 /* Start the decrementer on CPUs that have manual control
826 * such as BookE
827 */
828 start_cpu_decrementer();
829
830 /* FIME: Should make unrelatred change to move snapshot_timebase
831 * call here ! */
832 register_decrementer_clockevent(smp_processor_id());
833}
834
835/* This function is only called on the boot processor */
836void __init time_init(void)
837{
838 struct div_result res;
839 u64 scale;
840 unsigned shift;
841
842 if (__USE_RTC()) {
843 /* 601 processor: dec counts down by 128 every 128ns */
844 ppc_tb_freq = 1000000000;
845 } else {
846 /* Normal PowerPC with timebase register */
847 ppc_md.calibrate_decr();
848 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n",
849 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
850 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n",
851 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
852 }
853
854 tb_ticks_per_jiffy = ppc_tb_freq / HZ;
855 tb_ticks_per_sec = ppc_tb_freq;
856 tb_ticks_per_usec = ppc_tb_freq / 1000000;
857 calc_cputime_factors();
858 setup_cputime_one_jiffy();
859
860 /*
861 * Compute scale factor for sched_clock.
862 * The calibrate_decr() function has set tb_ticks_per_sec,
863 * which is the timebase frequency.
864 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
865 * the 128-bit result as a 64.64 fixed-point number.
866 * We then shift that number right until it is less than 1.0,
867 * giving us the scale factor and shift count to use in
868 * sched_clock().
869 */
870 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res);
871 scale = res.result_low;
872 for (shift = 0; res.result_high != 0; ++shift) {
873 scale = (scale >> 1) | (res.result_high << 63);
874 res.result_high >>= 1;
875 }
876 tb_to_ns_scale = scale;
877 tb_to_ns_shift = shift;
878 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
879 boot_tb = get_tb_or_rtc();
880
881 /* If platform provided a timezone (pmac), we correct the time */
882 if (timezone_offset) {
883 sys_tz.tz_minuteswest = -timezone_offset / 60;
884 sys_tz.tz_dsttime = 0;
885 }
886
887 vdso_data->tb_update_count = 0;
888 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
889
890 /* Start the decrementer on CPUs that have manual control
891 * such as BookE
892 */
893 start_cpu_decrementer();
894
895 /* Register the clocksource */
896 clocksource_init();
897
898 init_decrementer_clockevent();
899}
900
901
902#define FEBRUARY 2
903#define STARTOFTIME 1970
904#define SECDAY 86400L
905#define SECYR (SECDAY * 365)
906#define leapyear(year) ((year) % 4 == 0 && \
907 ((year) % 100 != 0 || (year) % 400 == 0))
908#define days_in_year(a) (leapyear(a) ? 366 : 365)
909#define days_in_month(a) (month_days[(a) - 1])
910
911static int month_days[12] = {
912 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
913};
914
915/*
916 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
917 */
918void GregorianDay(struct rtc_time * tm)
919{
920 int leapsToDate;
921 int lastYear;
922 int day;
923 int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
924
925 lastYear = tm->tm_year - 1;
926
927 /*
928 * Number of leap corrections to apply up to end of last year
929 */
930 leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400;
931
932 /*
933 * This year is a leap year if it is divisible by 4 except when it is
934 * divisible by 100 unless it is divisible by 400
935 *
936 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
937 */
938 day = tm->tm_mon > 2 && leapyear(tm->tm_year);
939
940 day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] +
941 tm->tm_mday;
942
943 tm->tm_wday = day % 7;
944}
945
946void to_tm(int tim, struct rtc_time * tm)
947{
948 register int i;
949 register long hms, day;
950
951 day = tim / SECDAY;
952 hms = tim % SECDAY;
953
954 /* Hours, minutes, seconds are easy */
955 tm->tm_hour = hms / 3600;
956 tm->tm_min = (hms % 3600) / 60;
957 tm->tm_sec = (hms % 3600) % 60;
958
959 /* Number of years in days */
960 for (i = STARTOFTIME; day >= days_in_year(i); i++)
961 day -= days_in_year(i);
962 tm->tm_year = i;
963
964 /* Number of months in days left */
965 if (leapyear(tm->tm_year))
966 days_in_month(FEBRUARY) = 29;
967 for (i = 1; day >= days_in_month(i); i++)
968 day -= days_in_month(i);
969 days_in_month(FEBRUARY) = 28;
970 tm->tm_mon = i;
971
972 /* Days are what is left over (+1) from all that. */
973 tm->tm_mday = day + 1;
974
975 /*
976 * Determine the day of week
977 */
978 GregorianDay(tm);
979}
980
981/*
982 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
983 * result.
984 */
985void div128_by_32(u64 dividend_high, u64 dividend_low,
986 unsigned divisor, struct div_result *dr)
987{
988 unsigned long a, b, c, d;
989 unsigned long w, x, y, z;
990 u64 ra, rb, rc;
991
992 a = dividend_high >> 32;
993 b = dividend_high & 0xffffffff;
994 c = dividend_low >> 32;
995 d = dividend_low & 0xffffffff;
996
997 w = a / divisor;
998 ra = ((u64)(a - (w * divisor)) << 32) + b;
999
1000 rb = ((u64) do_div(ra, divisor) << 32) + c;
1001 x = ra;
1002
1003 rc = ((u64) do_div(rb, divisor) << 32) + d;
1004 y = rb;
1005
1006 do_div(rc, divisor);
1007 z = rc;
1008
1009 dr->result_high = ((u64)w << 32) + x;
1010 dr->result_low = ((u64)y << 32) + z;
1011
1012}
1013
1014/* We don't need to calibrate delay, we use the CPU timebase for that */
1015void calibrate_delay(void)
1016{
1017 /* Some generic code (such as spinlock debug) use loops_per_jiffy
1018 * as the number of __delay(1) in a jiffy, so make it so
1019 */
1020 loops_per_jiffy = tb_ticks_per_jiffy;
1021}
1022
1023static int __init rtc_init(void)
1024{
1025 struct platform_device *pdev;
1026
1027 if (!ppc_md.get_rtc_time)
1028 return -ENODEV;
1029
1030 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0);
1031 if (IS_ERR(pdev))
1032 return PTR_ERR(pdev);
1033
1034 return 0;
1035}
1036
1037module_init(rtc_init);