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/sched/clock.h>
38 #include <linux/kernel.h>
39 #include <linux/param.h>
40 #include <linux/string.h>
41 #include <linux/mm.h>
42 #include <linux/interrupt.h>
43 #include <linux/timex.h>
44 #include <linux/kernel_stat.h>
45 #include <linux/time.h>
46 #include <linux/clockchips.h>
47 #include <linux/init.h>
48 #include <linux/profile.h>
49 #include <linux/cpu.h>
50 #include <linux/security.h>
51 #include <linux/percpu.h>
52 #include <linux/rtc.h>
53 #include <linux/jiffies.h>
54 #include <linux/posix-timers.h>
55 #include <linux/irq.h>
56 #include <linux/delay.h>
57 #include <linux/irq_work.h>
58 #include <linux/clk-provider.h>
59 #include <linux/suspend.h>
60 #include <linux/rtc.h>
61 #include <linux/sched/cputime.h>
62 #include <linux/processor.h>
63 #include <asm/trace.h>
64
65 #include <asm/io.h>
66 #include <asm/nvram.h>
67 #include <asm/cache.h>
68 #include <asm/machdep.h>
69 #include <linux/uaccess.h>
70 #include <asm/time.h>
71 #include <asm/prom.h>
72 #include <asm/irq.h>
73 #include <asm/div64.h>
74 #include <asm/smp.h>
75 #include <asm/vdso_datapage.h>
76 #include <asm/firmware.h>
77 #include <asm/asm-prototypes.h>
78
79 /* powerpc clocksource/clockevent code */
80
81 #include <linux/clockchips.h>
82 #include <linux/timekeeper_internal.h>
83
84 static u64 rtc_read(struct clocksource *);
85 static struct clocksource clocksource_rtc = {
86 .name = "rtc",
87 .rating = 400,
88 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
89 .mask = CLOCKSOURCE_MASK(64),
90 .read = rtc_read,
91 };
92
93 static u64 timebase_read(struct clocksource *);
94 static struct clocksource clocksource_timebase = {
95 .name = "timebase",
96 .rating = 400,
97 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
98 .mask = CLOCKSOURCE_MASK(64),
99 .read = timebase_read,
100 };
101
102 #define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF
103 u64 decrementer_max = DECREMENTER_DEFAULT_MAX;
104
105 static int decrementer_set_next_event(unsigned long evt,
106 struct clock_event_device *dev);
107 static int decrementer_shutdown(struct clock_event_device *evt);
108
109 struct clock_event_device decrementer_clockevent = {
110 .name = "decrementer",
111 .rating = 200,
112 .irq = 0,
113 .set_next_event = decrementer_set_next_event,
114 .set_state_shutdown = decrementer_shutdown,
115 .tick_resume = decrementer_shutdown,
116 .features = CLOCK_EVT_FEAT_ONESHOT |
117 CLOCK_EVT_FEAT_C3STOP,
118 };
119 EXPORT_SYMBOL(decrementer_clockevent);
120
121 DEFINE_PER_CPU(u64, decrementers_next_tb);
122 static DEFINE_PER_CPU(struct clock_event_device, decrementers);
123
124 #define XSEC_PER_SEC (1024*1024)
125
126 #ifdef CONFIG_PPC64
127 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
128 #else
129 /* compute ((xsec << 12) * max) >> 32 */
130 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
131 #endif
132
133 unsigned long tb_ticks_per_jiffy;
134 unsigned long tb_ticks_per_usec = 100; /* sane default */
135 EXPORT_SYMBOL(tb_ticks_per_usec);
136 unsigned long tb_ticks_per_sec;
137 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
138
139 DEFINE_SPINLOCK(rtc_lock);
140 EXPORT_SYMBOL_GPL(rtc_lock);
141
142 static u64 tb_to_ns_scale __read_mostly;
143 static unsigned tb_to_ns_shift __read_mostly;
144 static u64 boot_tb __read_mostly;
145
146 extern struct timezone sys_tz;
147 static long timezone_offset;
148
149 unsigned long ppc_proc_freq;
150 EXPORT_SYMBOL_GPL(ppc_proc_freq);
151 unsigned long ppc_tb_freq;
152 EXPORT_SYMBOL_GPL(ppc_tb_freq);
153
154 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
155 /*
156 * Factor for converting from cputime_t (timebase ticks) to
157 * microseconds. This is stored as 0.64 fixed-point binary fraction.
158 */
159 u64 __cputime_usec_factor;
160 EXPORT_SYMBOL(__cputime_usec_factor);
161
162 #ifdef CONFIG_PPC_SPLPAR
163 void (*dtl_consumer)(struct dtl_entry *, u64);
164 #endif
165
calc_cputime_factors(void)166 static void calc_cputime_factors(void)
167 {
168 struct div_result res;
169
170 div128_by_32(1000000, 0, tb_ticks_per_sec, &res);
171 __cputime_usec_factor = res.result_low;
172 }
173
174 /*
175 * Read the SPURR on systems that have it, otherwise the PURR,
176 * or if that doesn't exist return the timebase value passed in.
177 */
read_spurr(unsigned long tb)178 static unsigned long read_spurr(unsigned long tb)
179 {
180 if (cpu_has_feature(CPU_FTR_SPURR))
181 return mfspr(SPRN_SPURR);
182 if (cpu_has_feature(CPU_FTR_PURR))
183 return mfspr(SPRN_PURR);
184 return tb;
185 }
186
187 #ifdef CONFIG_PPC_SPLPAR
188
189 /*
190 * Scan the dispatch trace log and count up the stolen time.
191 * Should be called with interrupts disabled.
192 */
scan_dispatch_log(u64 stop_tb)193 static u64 scan_dispatch_log(u64 stop_tb)
194 {
195 u64 i = local_paca->dtl_ridx;
196 struct dtl_entry *dtl = local_paca->dtl_curr;
197 struct dtl_entry *dtl_end = local_paca->dispatch_log_end;
198 struct lppaca *vpa = local_paca->lppaca_ptr;
199 u64 tb_delta;
200 u64 stolen = 0;
201 u64 dtb;
202
203 if (!dtl)
204 return 0;
205
206 if (i == be64_to_cpu(vpa->dtl_idx))
207 return 0;
208 while (i < be64_to_cpu(vpa->dtl_idx)) {
209 dtb = be64_to_cpu(dtl->timebase);
210 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) +
211 be32_to_cpu(dtl->ready_to_enqueue_time);
212 barrier();
213 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) {
214 /* buffer has overflowed */
215 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG;
216 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG);
217 continue;
218 }
219 if (dtb > stop_tb)
220 break;
221 if (dtl_consumer)
222 dtl_consumer(dtl, i);
223 stolen += tb_delta;
224 ++i;
225 ++dtl;
226 if (dtl == dtl_end)
227 dtl = local_paca->dispatch_log;
228 }
229 local_paca->dtl_ridx = i;
230 local_paca->dtl_curr = dtl;
231 return stolen;
232 }
233
234 /*
235 * Accumulate stolen time by scanning the dispatch trace log.
236 * Called on entry from user mode.
237 */
accumulate_stolen_time(void)238 void accumulate_stolen_time(void)
239 {
240 u64 sst, ust;
241 unsigned long save_irq_soft_mask = irq_soft_mask_return();
242 struct cpu_accounting_data *acct = &local_paca->accounting;
243
244 /* We are called early in the exception entry, before
245 * soft/hard_enabled are sync'ed to the expected state
246 * for the exception. We are hard disabled but the PACA
247 * needs to reflect that so various debug stuff doesn't
248 * complain
249 */
250 irq_soft_mask_set(IRQS_DISABLED);
251
252 sst = scan_dispatch_log(acct->starttime_user);
253 ust = scan_dispatch_log(acct->starttime);
254 acct->stime -= sst;
255 acct->utime -= ust;
256 acct->steal_time += ust + sst;
257
258 irq_soft_mask_set(save_irq_soft_mask);
259 }
260
calculate_stolen_time(u64 stop_tb)261 static inline u64 calculate_stolen_time(u64 stop_tb)
262 {
263 if (!firmware_has_feature(FW_FEATURE_SPLPAR))
264 return 0;
265
266 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx))
267 return scan_dispatch_log(stop_tb);
268
269 return 0;
270 }
271
272 #else /* CONFIG_PPC_SPLPAR */
calculate_stolen_time(u64 stop_tb)273 static inline u64 calculate_stolen_time(u64 stop_tb)
274 {
275 return 0;
276 }
277
278 #endif /* CONFIG_PPC_SPLPAR */
279
280 /*
281 * Account time for a transition between system, hard irq
282 * or soft irq state.
283 */
vtime_delta(struct task_struct * tsk,unsigned long * stime_scaled,unsigned long * steal_time)284 static unsigned long vtime_delta(struct task_struct *tsk,
285 unsigned long *stime_scaled,
286 unsigned long *steal_time)
287 {
288 unsigned long now, nowscaled, deltascaled;
289 unsigned long stime;
290 unsigned long utime, utime_scaled;
291 struct cpu_accounting_data *acct = get_accounting(tsk);
292
293 WARN_ON_ONCE(!irqs_disabled());
294
295 now = mftb();
296 nowscaled = read_spurr(now);
297 stime = now - acct->starttime;
298 acct->starttime = now;
299 deltascaled = nowscaled - acct->startspurr;
300 acct->startspurr = nowscaled;
301
302 *steal_time = calculate_stolen_time(now);
303
304 utime = acct->utime - acct->utime_sspurr;
305 acct->utime_sspurr = acct->utime;
306
307 /*
308 * Because we don't read the SPURR on every kernel entry/exit,
309 * deltascaled includes both user and system SPURR ticks.
310 * Apportion these ticks to system SPURR ticks and user
311 * SPURR ticks in the same ratio as the system time (delta)
312 * and user time (udelta) values obtained from the timebase
313 * over the same interval. The system ticks get accounted here;
314 * the user ticks get saved up in paca->user_time_scaled to be
315 * used by account_process_tick.
316 */
317 *stime_scaled = stime;
318 utime_scaled = utime;
319 if (deltascaled != stime + utime) {
320 if (utime) {
321 *stime_scaled = deltascaled * stime / (stime + utime);
322 utime_scaled = deltascaled - *stime_scaled;
323 } else {
324 *stime_scaled = deltascaled;
325 }
326 }
327 acct->utime_scaled += utime_scaled;
328
329 return stime;
330 }
331
vtime_account_system(struct task_struct * tsk)332 void vtime_account_system(struct task_struct *tsk)
333 {
334 unsigned long stime, stime_scaled, steal_time;
335 struct cpu_accounting_data *acct = get_accounting(tsk);
336
337 stime = vtime_delta(tsk, &stime_scaled, &steal_time);
338
339 stime -= min(stime, steal_time);
340 acct->steal_time += steal_time;
341
342 if ((tsk->flags & PF_VCPU) && !irq_count()) {
343 acct->gtime += stime;
344 acct->utime_scaled += stime_scaled;
345 } else {
346 if (hardirq_count())
347 acct->hardirq_time += stime;
348 else if (in_serving_softirq())
349 acct->softirq_time += stime;
350 else
351 acct->stime += stime;
352
353 acct->stime_scaled += stime_scaled;
354 }
355 }
356 EXPORT_SYMBOL_GPL(vtime_account_system);
357
vtime_account_idle(struct task_struct * tsk)358 void vtime_account_idle(struct task_struct *tsk)
359 {
360 unsigned long stime, stime_scaled, steal_time;
361 struct cpu_accounting_data *acct = get_accounting(tsk);
362
363 stime = vtime_delta(tsk, &stime_scaled, &steal_time);
364 acct->idle_time += stime + steal_time;
365 }
366
367 /*
368 * Account the whole cputime accumulated in the paca
369 * Must be called with interrupts disabled.
370 * Assumes that vtime_account_system/idle() has been called
371 * recently (i.e. since the last entry from usermode) so that
372 * get_paca()->user_time_scaled is up to date.
373 */
vtime_flush(struct task_struct * tsk)374 void vtime_flush(struct task_struct *tsk)
375 {
376 struct cpu_accounting_data *acct = get_accounting(tsk);
377
378 if (acct->utime)
379 account_user_time(tsk, cputime_to_nsecs(acct->utime));
380
381 if (acct->utime_scaled)
382 tsk->utimescaled += cputime_to_nsecs(acct->utime_scaled);
383
384 if (acct->gtime)
385 account_guest_time(tsk, cputime_to_nsecs(acct->gtime));
386
387 if (acct->steal_time)
388 account_steal_time(cputime_to_nsecs(acct->steal_time));
389
390 if (acct->idle_time)
391 account_idle_time(cputime_to_nsecs(acct->idle_time));
392
393 if (acct->stime)
394 account_system_index_time(tsk, cputime_to_nsecs(acct->stime),
395 CPUTIME_SYSTEM);
396 if (acct->stime_scaled)
397 tsk->stimescaled += cputime_to_nsecs(acct->stime_scaled);
398
399 if (acct->hardirq_time)
400 account_system_index_time(tsk, cputime_to_nsecs(acct->hardirq_time),
401 CPUTIME_IRQ);
402 if (acct->softirq_time)
403 account_system_index_time(tsk, cputime_to_nsecs(acct->softirq_time),
404 CPUTIME_SOFTIRQ);
405
406 acct->utime = 0;
407 acct->utime_scaled = 0;
408 acct->utime_sspurr = 0;
409 acct->gtime = 0;
410 acct->steal_time = 0;
411 acct->idle_time = 0;
412 acct->stime = 0;
413 acct->stime_scaled = 0;
414 acct->hardirq_time = 0;
415 acct->softirq_time = 0;
416 }
417
418 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
419 #define calc_cputime_factors()
420 #endif
421
__delay(unsigned long loops)422 void __delay(unsigned long loops)
423 {
424 unsigned long start;
425 int diff;
426
427 spin_begin();
428 if (__USE_RTC()) {
429 start = get_rtcl();
430 do {
431 /* the RTCL register wraps at 1000000000 */
432 diff = get_rtcl() - start;
433 if (diff < 0)
434 diff += 1000000000;
435 spin_cpu_relax();
436 } while (diff < loops);
437 } else {
438 start = get_tbl();
439 while (get_tbl() - start < loops)
440 spin_cpu_relax();
441 }
442 spin_end();
443 }
444 EXPORT_SYMBOL(__delay);
445
udelay(unsigned long usecs)446 void udelay(unsigned long usecs)
447 {
448 __delay(tb_ticks_per_usec * usecs);
449 }
450 EXPORT_SYMBOL(udelay);
451
452 #ifdef CONFIG_SMP
profile_pc(struct pt_regs * regs)453 unsigned long profile_pc(struct pt_regs *regs)
454 {
455 unsigned long pc = instruction_pointer(regs);
456
457 if (in_lock_functions(pc))
458 return regs->link;
459
460 return pc;
461 }
462 EXPORT_SYMBOL(profile_pc);
463 #endif
464
465 #ifdef CONFIG_IRQ_WORK
466
467 /*
468 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable...
469 */
470 #ifdef CONFIG_PPC64
test_irq_work_pending(void)471 static inline unsigned long test_irq_work_pending(void)
472 {
473 unsigned long x;
474
475 asm volatile("lbz %0,%1(13)"
476 : "=r" (x)
477 : "i" (offsetof(struct paca_struct, irq_work_pending)));
478 return x;
479 }
480
set_irq_work_pending_flag(void)481 static inline void set_irq_work_pending_flag(void)
482 {
483 asm volatile("stb %0,%1(13)" : :
484 "r" (1),
485 "i" (offsetof(struct paca_struct, irq_work_pending)));
486 }
487
clear_irq_work_pending(void)488 static inline void clear_irq_work_pending(void)
489 {
490 asm volatile("stb %0,%1(13)" : :
491 "r" (0),
492 "i" (offsetof(struct paca_struct, irq_work_pending)));
493 }
494
arch_irq_work_raise(void)495 void arch_irq_work_raise(void)
496 {
497 preempt_disable();
498 set_irq_work_pending_flag();
499 /*
500 * Non-nmi code running with interrupts disabled will replay
501 * irq_happened before it re-enables interrupts, so setthe
502 * decrementer there instead of causing a hardware exception
503 * which would immediately hit the masked interrupt handler
504 * and have the net effect of setting the decrementer in
505 * irq_happened.
506 *
507 * NMI interrupts can not check this when they return, so the
508 * decrementer hardware exception is raised, which will fire
509 * when interrupts are next enabled.
510 *
511 * BookE does not support this yet, it must audit all NMI
512 * interrupt handlers to ensure they call nmi_enter() so this
513 * check would be correct.
514 */
515 if (IS_ENABLED(CONFIG_BOOKE) || !irqs_disabled() || in_nmi()) {
516 set_dec(1);
517 } else {
518 hard_irq_disable();
519 local_paca->irq_happened |= PACA_IRQ_DEC;
520 }
521 preempt_enable();
522 }
523
524 #else /* 32-bit */
525
526 DEFINE_PER_CPU(u8, irq_work_pending);
527
528 #define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1)
529 #define test_irq_work_pending() __this_cpu_read(irq_work_pending)
530 #define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0)
531
arch_irq_work_raise(void)532 void arch_irq_work_raise(void)
533 {
534 preempt_disable();
535 set_irq_work_pending_flag();
536 set_dec(1);
537 preempt_enable();
538 }
539
540 #endif /* 32 vs 64 bit */
541
542 #else /* CONFIG_IRQ_WORK */
543
544 #define test_irq_work_pending() 0
545 #define clear_irq_work_pending()
546
547 #endif /* CONFIG_IRQ_WORK */
548
549 /*
550 * timer_interrupt - gets called when the decrementer overflows,
551 * with interrupts disabled.
552 */
timer_interrupt(struct pt_regs * regs)553 void timer_interrupt(struct pt_regs *regs)
554 {
555 struct clock_event_device *evt = this_cpu_ptr(&decrementers);
556 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb);
557 struct pt_regs *old_regs;
558 u64 now;
559
560 /* Some implementations of hotplug will get timer interrupts while
561 * offline, just ignore these and we also need to set
562 * decrementers_next_tb as MAX to make sure __check_irq_replay
563 * don't replay timer interrupt when return, otherwise we'll trap
564 * here infinitely :(
565 */
566 if (unlikely(!cpu_online(smp_processor_id()))) {
567 *next_tb = ~(u64)0;
568 set_dec(decrementer_max);
569 return;
570 }
571
572 /* Ensure a positive value is written to the decrementer, or else
573 * some CPUs will continue to take decrementer exceptions. When the
574 * PPC_WATCHDOG (decrementer based) is configured, keep this at most
575 * 31 bits, which is about 4 seconds on most systems, which gives
576 * the watchdog a chance of catching timer interrupt hard lockups.
577 */
578 if (IS_ENABLED(CONFIG_PPC_WATCHDOG))
579 set_dec(0x7fffffff);
580 else
581 set_dec(decrementer_max);
582
583 /* Conditionally hard-enable interrupts now that the DEC has been
584 * bumped to its maximum value
585 */
586 may_hard_irq_enable();
587
588
589 #if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC)
590 if (atomic_read(&ppc_n_lost_interrupts) != 0)
591 do_IRQ(regs);
592 #endif
593
594 old_regs = set_irq_regs(regs);
595 irq_enter();
596 trace_timer_interrupt_entry(regs);
597
598 if (test_irq_work_pending()) {
599 clear_irq_work_pending();
600 irq_work_run();
601 }
602
603 now = get_tb_or_rtc();
604 if (now >= *next_tb) {
605 *next_tb = ~(u64)0;
606 if (evt->event_handler)
607 evt->event_handler(evt);
608 __this_cpu_inc(irq_stat.timer_irqs_event);
609 } else {
610 now = *next_tb - now;
611 if (now <= decrementer_max)
612 set_dec(now);
613 /* We may have raced with new irq work */
614 if (test_irq_work_pending())
615 set_dec(1);
616 __this_cpu_inc(irq_stat.timer_irqs_others);
617 }
618
619 trace_timer_interrupt_exit(regs);
620 irq_exit();
621 set_irq_regs(old_regs);
622 }
623 EXPORT_SYMBOL(timer_interrupt);
624
625 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
timer_broadcast_interrupt(void)626 void timer_broadcast_interrupt(void)
627 {
628 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb);
629
630 *next_tb = ~(u64)0;
631 tick_receive_broadcast();
632 __this_cpu_inc(irq_stat.broadcast_irqs_event);
633 }
634 #endif
635
636 /*
637 * Hypervisor decrementer interrupts shouldn't occur but are sometimes
638 * left pending on exit from a KVM guest. We don't need to do anything
639 * to clear them, as they are edge-triggered.
640 */
hdec_interrupt(struct pt_regs * regs)641 void hdec_interrupt(struct pt_regs *regs)
642 {
643 }
644
645 #ifdef CONFIG_SUSPEND
generic_suspend_disable_irqs(void)646 static void generic_suspend_disable_irqs(void)
647 {
648 /* Disable the decrementer, so that it doesn't interfere
649 * with suspending.
650 */
651
652 set_dec(decrementer_max);
653 local_irq_disable();
654 set_dec(decrementer_max);
655 }
656
generic_suspend_enable_irqs(void)657 static void generic_suspend_enable_irqs(void)
658 {
659 local_irq_enable();
660 }
661
662 /* Overrides the weak version in kernel/power/main.c */
arch_suspend_disable_irqs(void)663 void arch_suspend_disable_irqs(void)
664 {
665 if (ppc_md.suspend_disable_irqs)
666 ppc_md.suspend_disable_irqs();
667 generic_suspend_disable_irqs();
668 }
669
670 /* Overrides the weak version in kernel/power/main.c */
arch_suspend_enable_irqs(void)671 void arch_suspend_enable_irqs(void)
672 {
673 generic_suspend_enable_irqs();
674 if (ppc_md.suspend_enable_irqs)
675 ppc_md.suspend_enable_irqs();
676 }
677 #endif
678
tb_to_ns(unsigned long long ticks)679 unsigned long long tb_to_ns(unsigned long long ticks)
680 {
681 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift;
682 }
683 EXPORT_SYMBOL_GPL(tb_to_ns);
684
685 /*
686 * Scheduler clock - returns current time in nanosec units.
687 *
688 * Note: mulhdu(a, b) (multiply high double unsigned) returns
689 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
690 * are 64-bit unsigned numbers.
691 */
sched_clock(void)692 notrace unsigned long long sched_clock(void)
693 {
694 if (__USE_RTC())
695 return get_rtc();
696 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
697 }
698
699
700 #ifdef CONFIG_PPC_PSERIES
701
702 /*
703 * Running clock - attempts to give a view of time passing for a virtualised
704 * kernels.
705 * Uses the VTB register if available otherwise a next best guess.
706 */
running_clock(void)707 unsigned long long running_clock(void)
708 {
709 /*
710 * Don't read the VTB as a host since KVM does not switch in host
711 * timebase into the VTB when it takes a guest off the CPU, reading the
712 * VTB would result in reading 'last switched out' guest VTB.
713 *
714 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it
715 * would be unsafe to rely only on the #ifdef above.
716 */
717 if (firmware_has_feature(FW_FEATURE_LPAR) &&
718 cpu_has_feature(CPU_FTR_ARCH_207S))
719 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
720
721 /*
722 * This is a next best approximation without a VTB.
723 * On a host which is running bare metal there should never be any stolen
724 * time and on a host which doesn't do any virtualisation TB *should* equal
725 * VTB so it makes no difference anyway.
726 */
727 return local_clock() - kcpustat_this_cpu->cpustat[CPUTIME_STEAL];
728 }
729 #endif
730
get_freq(char * name,int cells,unsigned long * val)731 static int __init get_freq(char *name, int cells, unsigned long *val)
732 {
733 struct device_node *cpu;
734 const __be32 *fp;
735 int found = 0;
736
737 /* The cpu node should have timebase and clock frequency properties */
738 cpu = of_find_node_by_type(NULL, "cpu");
739
740 if (cpu) {
741 fp = of_get_property(cpu, name, NULL);
742 if (fp) {
743 found = 1;
744 *val = of_read_ulong(fp, cells);
745 }
746
747 of_node_put(cpu);
748 }
749
750 return found;
751 }
752
start_cpu_decrementer(void)753 static void start_cpu_decrementer(void)
754 {
755 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
756 unsigned int tcr;
757
758 /* Clear any pending timer interrupts */
759 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS);
760
761 tcr = mfspr(SPRN_TCR);
762 /*
763 * The watchdog may have already been enabled by u-boot. So leave
764 * TRC[WP] (Watchdog Period) alone.
765 */
766 tcr &= TCR_WP_MASK; /* Clear all bits except for TCR[WP] */
767 tcr |= TCR_DIE; /* Enable decrementer */
768 mtspr(SPRN_TCR, tcr);
769 #endif
770 }
771
generic_calibrate_decr(void)772 void __init generic_calibrate_decr(void)
773 {
774 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */
775
776 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) &&
777 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) {
778
779 printk(KERN_ERR "WARNING: Estimating decrementer frequency "
780 "(not found)\n");
781 }
782
783 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */
784
785 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) &&
786 !get_freq("clock-frequency", 1, &ppc_proc_freq)) {
787
788 printk(KERN_ERR "WARNING: Estimating processor frequency "
789 "(not found)\n");
790 }
791 }
792
update_persistent_clock64(struct timespec64 now)793 int update_persistent_clock64(struct timespec64 now)
794 {
795 struct rtc_time tm;
796
797 if (!ppc_md.set_rtc_time)
798 return -ENODEV;
799
800 rtc_time64_to_tm(now.tv_sec + 1 + timezone_offset, &tm);
801
802 return ppc_md.set_rtc_time(&tm);
803 }
804
__read_persistent_clock(struct timespec64 * ts)805 static void __read_persistent_clock(struct timespec64 *ts)
806 {
807 struct rtc_time tm;
808 static int first = 1;
809
810 ts->tv_nsec = 0;
811 /* XXX this is a litle fragile but will work okay in the short term */
812 if (first) {
813 first = 0;
814 if (ppc_md.time_init)
815 timezone_offset = ppc_md.time_init();
816
817 /* get_boot_time() isn't guaranteed to be safe to call late */
818 if (ppc_md.get_boot_time) {
819 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset;
820 return;
821 }
822 }
823 if (!ppc_md.get_rtc_time) {
824 ts->tv_sec = 0;
825 return;
826 }
827 ppc_md.get_rtc_time(&tm);
828
829 ts->tv_sec = rtc_tm_to_time64(&tm);
830 }
831
read_persistent_clock64(struct timespec64 * ts)832 void read_persistent_clock64(struct timespec64 *ts)
833 {
834 __read_persistent_clock(ts);
835
836 /* Sanitize it in case real time clock is set below EPOCH */
837 if (ts->tv_sec < 0) {
838 ts->tv_sec = 0;
839 ts->tv_nsec = 0;
840 }
841
842 }
843
844 /* clocksource code */
rtc_read(struct clocksource * cs)845 static notrace u64 rtc_read(struct clocksource *cs)
846 {
847 return (u64)get_rtc();
848 }
849
timebase_read(struct clocksource * cs)850 static notrace u64 timebase_read(struct clocksource *cs)
851 {
852 return (u64)get_tb();
853 }
854
855
update_vsyscall(struct timekeeper * tk)856 void update_vsyscall(struct timekeeper *tk)
857 {
858 struct timespec xt;
859 struct clocksource *clock = tk->tkr_mono.clock;
860 u32 mult = tk->tkr_mono.mult;
861 u32 shift = tk->tkr_mono.shift;
862 u64 cycle_last = tk->tkr_mono.cycle_last;
863 u64 new_tb_to_xs, new_stamp_xsec;
864 u64 frac_sec;
865
866 if (clock != &clocksource_timebase)
867 return;
868
869 xt.tv_sec = tk->xtime_sec;
870 xt.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
871
872 /* Make userspace gettimeofday spin until we're done. */
873 ++vdso_data->tb_update_count;
874 smp_mb();
875
876 /*
877 * This computes ((2^20 / 1e9) * mult) >> shift as a
878 * 0.64 fixed-point fraction.
879 * The computation in the else clause below won't overflow
880 * (as long as the timebase frequency is >= 1.049 MHz)
881 * but loses precision because we lose the low bits of the constant
882 * in the shift. Note that 19342813113834067 ~= 2^(20+64) / 1e9.
883 * For a shift of 24 the error is about 0.5e-9, or about 0.5ns
884 * over a second. (Shift values are usually 22, 23 or 24.)
885 * For high frequency clocks such as the 512MHz timebase clock
886 * on POWER[6789], the mult value is small (e.g. 32768000)
887 * and so we can shift the constant by 16 initially
888 * (295147905179 ~= 2^(20+64-16) / 1e9) and then do the
889 * remaining shifts after the multiplication, which gives a
890 * more accurate result (e.g. with mult = 32768000, shift = 24,
891 * the error is only about 1.2e-12, or 0.7ns over 10 minutes).
892 */
893 if (mult <= 62500000 && clock->shift >= 16)
894 new_tb_to_xs = ((u64) mult * 295147905179ULL) >> (clock->shift - 16);
895 else
896 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift);
897
898 /*
899 * Compute the fractional second in units of 2^-32 seconds.
900 * The fractional second is tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift
901 * in nanoseconds, so multiplying that by 2^32 / 1e9 gives
902 * it in units of 2^-32 seconds.
903 * We assume shift <= 32 because clocks_calc_mult_shift()
904 * generates shift values in the range 0 - 32.
905 */
906 frac_sec = tk->tkr_mono.xtime_nsec << (32 - shift);
907 do_div(frac_sec, NSEC_PER_SEC);
908
909 /*
910 * Work out new stamp_xsec value for any legacy users of systemcfg.
911 * stamp_xsec is in units of 2^-20 seconds.
912 */
913 new_stamp_xsec = frac_sec >> 12;
914 new_stamp_xsec += tk->xtime_sec * XSEC_PER_SEC;
915
916 /*
917 * tb_update_count is used to allow the userspace gettimeofday code
918 * to assure itself that it sees a consistent view of the tb_to_xs and
919 * stamp_xsec variables. It reads the tb_update_count, then reads
920 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
921 * the two values of tb_update_count match and are even then the
922 * tb_to_xs and stamp_xsec values are consistent. If not, then it
923 * loops back and reads them again until this criteria is met.
924 */
925 vdso_data->tb_orig_stamp = cycle_last;
926 vdso_data->stamp_xsec = new_stamp_xsec;
927 vdso_data->tb_to_xs = new_tb_to_xs;
928 vdso_data->wtom_clock_sec = tk->wall_to_monotonic.tv_sec;
929 vdso_data->wtom_clock_nsec = tk->wall_to_monotonic.tv_nsec;
930 vdso_data->stamp_xtime = xt;
931 vdso_data->stamp_sec_fraction = frac_sec;
932 smp_wmb();
933 ++(vdso_data->tb_update_count);
934 }
935
update_vsyscall_tz(void)936 void update_vsyscall_tz(void)
937 {
938 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
939 vdso_data->tz_dsttime = sys_tz.tz_dsttime;
940 }
941
clocksource_init(void)942 static void __init clocksource_init(void)
943 {
944 struct clocksource *clock;
945
946 if (__USE_RTC())
947 clock = &clocksource_rtc;
948 else
949 clock = &clocksource_timebase;
950
951 if (clocksource_register_hz(clock, tb_ticks_per_sec)) {
952 printk(KERN_ERR "clocksource: %s is already registered\n",
953 clock->name);
954 return;
955 }
956
957 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n",
958 clock->name, clock->mult, clock->shift);
959 }
960
decrementer_set_next_event(unsigned long evt,struct clock_event_device * dev)961 static int decrementer_set_next_event(unsigned long evt,
962 struct clock_event_device *dev)
963 {
964 __this_cpu_write(decrementers_next_tb, get_tb_or_rtc() + evt);
965 set_dec(evt);
966
967 /* We may have raced with new irq work */
968 if (test_irq_work_pending())
969 set_dec(1);
970
971 return 0;
972 }
973
decrementer_shutdown(struct clock_event_device * dev)974 static int decrementer_shutdown(struct clock_event_device *dev)
975 {
976 decrementer_set_next_event(decrementer_max, dev);
977 return 0;
978 }
979
register_decrementer_clockevent(int cpu)980 static void register_decrementer_clockevent(int cpu)
981 {
982 struct clock_event_device *dec = &per_cpu(decrementers, cpu);
983
984 *dec = decrementer_clockevent;
985 dec->cpumask = cpumask_of(cpu);
986
987 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n",
988 dec->name, dec->mult, dec->shift, cpu);
989
990 clockevents_register_device(dec);
991 }
992
enable_large_decrementer(void)993 static void enable_large_decrementer(void)
994 {
995 if (!cpu_has_feature(CPU_FTR_ARCH_300))
996 return;
997
998 if (decrementer_max <= DECREMENTER_DEFAULT_MAX)
999 return;
1000
1001 /*
1002 * If we're running as the hypervisor we need to enable the LD manually
1003 * otherwise firmware should have done it for us.
1004 */
1005 if (cpu_has_feature(CPU_FTR_HVMODE))
1006 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD);
1007 }
1008
set_decrementer_max(void)1009 static void __init set_decrementer_max(void)
1010 {
1011 struct device_node *cpu;
1012 u32 bits = 32;
1013
1014 /* Prior to ISAv3 the decrementer is always 32 bit */
1015 if (!cpu_has_feature(CPU_FTR_ARCH_300))
1016 return;
1017
1018 cpu = of_find_node_by_type(NULL, "cpu");
1019
1020 if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) {
1021 if (bits > 64 || bits < 32) {
1022 pr_warn("time_init: firmware supplied invalid ibm,dec-bits");
1023 bits = 32;
1024 }
1025
1026 /* calculate the signed maximum given this many bits */
1027 decrementer_max = (1ul << (bits - 1)) - 1;
1028 }
1029
1030 of_node_put(cpu);
1031
1032 pr_info("time_init: %u bit decrementer (max: %llx)\n",
1033 bits, decrementer_max);
1034 }
1035
init_decrementer_clockevent(void)1036 static void __init init_decrementer_clockevent(void)
1037 {
1038 int cpu = smp_processor_id();
1039
1040 clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4);
1041
1042 decrementer_clockevent.max_delta_ns =
1043 clockevent_delta2ns(decrementer_max, &decrementer_clockevent);
1044 decrementer_clockevent.max_delta_ticks = decrementer_max;
1045 decrementer_clockevent.min_delta_ns =
1046 clockevent_delta2ns(2, &decrementer_clockevent);
1047 decrementer_clockevent.min_delta_ticks = 2;
1048
1049 register_decrementer_clockevent(cpu);
1050 }
1051
secondary_cpu_time_init(void)1052 void 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 */
time_init(void)1068 void __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 #ifdef CONFIG_COMMON_CLK
1137 of_clk_init(NULL);
1138 #endif
1139 }
1140
1141 /*
1142 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1143 * result.
1144 */
div128_by_32(u64 dividend_high,u64 dividend_low,unsigned divisor,struct div_result * dr)1145 void div128_by_32(u64 dividend_high, u64 dividend_low,
1146 unsigned divisor, struct div_result *dr)
1147 {
1148 unsigned long a, b, c, d;
1149 unsigned long w, x, y, z;
1150 u64 ra, rb, rc;
1151
1152 a = dividend_high >> 32;
1153 b = dividend_high & 0xffffffff;
1154 c = dividend_low >> 32;
1155 d = dividend_low & 0xffffffff;
1156
1157 w = a / divisor;
1158 ra = ((u64)(a - (w * divisor)) << 32) + b;
1159
1160 rb = ((u64) do_div(ra, divisor) << 32) + c;
1161 x = ra;
1162
1163 rc = ((u64) do_div(rb, divisor) << 32) + d;
1164 y = rb;
1165
1166 do_div(rc, divisor);
1167 z = rc;
1168
1169 dr->result_high = ((u64)w << 32) + x;
1170 dr->result_low = ((u64)y << 32) + z;
1171
1172 }
1173
1174 /* We don't need to calibrate delay, we use the CPU timebase for that */
calibrate_delay(void)1175 void calibrate_delay(void)
1176 {
1177 /* Some generic code (such as spinlock debug) use loops_per_jiffy
1178 * as the number of __delay(1) in a jiffy, so make it so
1179 */
1180 loops_per_jiffy = tb_ticks_per_jiffy;
1181 }
1182
1183 #if IS_ENABLED(CONFIG_RTC_DRV_GENERIC)
rtc_generic_get_time(struct device * dev,struct rtc_time * tm)1184 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
1185 {
1186 ppc_md.get_rtc_time(tm);
1187 return 0;
1188 }
1189
rtc_generic_set_time(struct device * dev,struct rtc_time * tm)1190 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)
1191 {
1192 if (!ppc_md.set_rtc_time)
1193 return -EOPNOTSUPP;
1194
1195 if (ppc_md.set_rtc_time(tm) < 0)
1196 return -EOPNOTSUPP;
1197
1198 return 0;
1199 }
1200
1201 static const struct rtc_class_ops rtc_generic_ops = {
1202 .read_time = rtc_generic_get_time,
1203 .set_time = rtc_generic_set_time,
1204 };
1205
rtc_init(void)1206 static int __init rtc_init(void)
1207 {
1208 struct platform_device *pdev;
1209
1210 if (!ppc_md.get_rtc_time)
1211 return -ENODEV;
1212
1213 pdev = platform_device_register_data(NULL, "rtc-generic", -1,
1214 &rtc_generic_ops,
1215 sizeof(rtc_generic_ops));
1216
1217 return PTR_ERR_OR_ZERO(pdev);
1218 }
1219
1220 device_initcall(rtc_init);
1221 #endif
1222
