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