1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Common time routines among all ppc machines.
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)
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).
16 * Speeded up do_gettimeofday by getting rid of references to
17 * xtime (which required locks for consistency). (mikejc@us.ibm.com)
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.
26 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
27 * "A Kernel Model for Precision Timekeeping" by Dave Mills
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>
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/sched/clock.h>
57 #include <linux/processor.h>
58 #include <asm/trace.h>
60 #include <asm/interrupt.h>
62 #include <asm/nvram.h>
63 #include <asm/cache.h>
64 #include <asm/machdep.h>
65 #include <linux/uaccess.h>
69 #include <asm/div64.h>
71 #include <asm/vdso_datapage.h>
72 #include <asm/firmware.h>
73 #include <asm/asm-prototypes.h>
75 /* powerpc clocksource/clockevent code */
77 #include <linux/clockchips.h>
78 #include <linux/timekeeper_internal.h>
80 static u64 timebase_read(struct clocksource *);
81 static struct clocksource clocksource_timebase = {
84 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
85 .mask = CLOCKSOURCE_MASK(64),
86 .read = timebase_read,
87 .vdso_clock_mode = VDSO_CLOCKMODE_ARCHTIMER,
90 #define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF
91 u64 decrementer_max = DECREMENTER_DEFAULT_MAX;
93 static int decrementer_set_next_event(unsigned long evt,
94 struct clock_event_device *dev);
95 static int decrementer_shutdown(struct clock_event_device *evt);
97 struct clock_event_device decrementer_clockevent = {
98 .name = "decrementer",
101 .set_next_event = decrementer_set_next_event,
102 .set_state_oneshot_stopped = decrementer_shutdown,
103 .set_state_shutdown = decrementer_shutdown,
104 .tick_resume = decrementer_shutdown,
105 .features = CLOCK_EVT_FEAT_ONESHOT |
106 CLOCK_EVT_FEAT_C3STOP,
108 EXPORT_SYMBOL(decrementer_clockevent);
110 DEFINE_PER_CPU(u64, decrementers_next_tb);
111 static DEFINE_PER_CPU(struct clock_event_device, decrementers);
113 #define XSEC_PER_SEC (1024*1024)
116 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
118 /* compute ((xsec << 12) * max) >> 32 */
119 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
122 unsigned long tb_ticks_per_jiffy;
123 unsigned long tb_ticks_per_usec = 100; /* sane default */
124 EXPORT_SYMBOL(tb_ticks_per_usec);
125 unsigned long tb_ticks_per_sec;
126 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
128 DEFINE_SPINLOCK(rtc_lock);
129 EXPORT_SYMBOL_GPL(rtc_lock);
131 static u64 tb_to_ns_scale __read_mostly;
132 static unsigned tb_to_ns_shift __read_mostly;
133 static u64 boot_tb __read_mostly;
135 extern struct timezone sys_tz;
136 static long timezone_offset;
138 unsigned long ppc_proc_freq;
139 EXPORT_SYMBOL_GPL(ppc_proc_freq);
140 unsigned long ppc_tb_freq;
141 EXPORT_SYMBOL_GPL(ppc_tb_freq);
145 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
147 * Factor for converting from cputime_t (timebase ticks) to
148 * microseconds. This is stored as 0.64 fixed-point binary fraction.
150 u64 __cputime_usec_factor;
151 EXPORT_SYMBOL(__cputime_usec_factor);
153 #ifdef CONFIG_PPC_SPLPAR
154 void (*dtl_consumer)(struct dtl_entry *, u64);
157 static void calc_cputime_factors(void)
159 struct div_result res;
161 div128_by_32(1000000, 0, tb_ticks_per_sec, &res);
162 __cputime_usec_factor = res.result_low;
166 * Read the SPURR on systems that have it, otherwise the PURR,
167 * or if that doesn't exist return the timebase value passed in.
169 static inline unsigned long read_spurr(unsigned long tb)
171 if (cpu_has_feature(CPU_FTR_SPURR))
172 return mfspr(SPRN_SPURR);
173 if (cpu_has_feature(CPU_FTR_PURR))
174 return mfspr(SPRN_PURR);
178 #ifdef CONFIG_PPC_SPLPAR
183 * Scan the dispatch trace log and count up the stolen time.
184 * Should be called with interrupts disabled.
186 static u64 scan_dispatch_log(u64 stop_tb)
188 u64 i = local_paca->dtl_ridx;
189 struct dtl_entry *dtl = local_paca->dtl_curr;
190 struct dtl_entry *dtl_end = local_paca->dispatch_log_end;
191 struct lppaca *vpa = local_paca->lppaca_ptr;
199 if (i == be64_to_cpu(vpa->dtl_idx))
201 while (i < be64_to_cpu(vpa->dtl_idx)) {
202 dtb = be64_to_cpu(dtl->timebase);
203 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) +
204 be32_to_cpu(dtl->ready_to_enqueue_time);
206 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) {
207 /* buffer has overflowed */
208 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG;
209 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG);
215 dtl_consumer(dtl, i);
220 dtl = local_paca->dispatch_log;
222 local_paca->dtl_ridx = i;
223 local_paca->dtl_curr = dtl;
228 * Accumulate stolen time by scanning the dispatch trace log.
229 * Called on entry from user mode.
231 void notrace accumulate_stolen_time(void)
234 struct cpu_accounting_data *acct = &local_paca->accounting;
236 sst = scan_dispatch_log(acct->starttime_user);
237 ust = scan_dispatch_log(acct->starttime);
240 acct->steal_time += ust + sst;
243 static inline u64 calculate_stolen_time(u64 stop_tb)
245 if (!firmware_has_feature(FW_FEATURE_SPLPAR))
248 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx))
249 return scan_dispatch_log(stop_tb);
254 #else /* CONFIG_PPC_SPLPAR */
255 static inline u64 calculate_stolen_time(u64 stop_tb)
260 #endif /* CONFIG_PPC_SPLPAR */
263 * Account time for a transition between system, hard irq
266 static unsigned long vtime_delta_scaled(struct cpu_accounting_data *acct,
267 unsigned long now, unsigned long stime)
269 unsigned long stime_scaled = 0;
270 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
271 unsigned long nowscaled, deltascaled;
272 unsigned long utime, utime_scaled;
274 nowscaled = read_spurr(now);
275 deltascaled = nowscaled - acct->startspurr;
276 acct->startspurr = nowscaled;
277 utime = acct->utime - acct->utime_sspurr;
278 acct->utime_sspurr = acct->utime;
281 * Because we don't read the SPURR on every kernel entry/exit,
282 * deltascaled includes both user and system SPURR ticks.
283 * Apportion these ticks to system SPURR ticks and user
284 * SPURR ticks in the same ratio as the system time (delta)
285 * and user time (udelta) values obtained from the timebase
286 * over the same interval. The system ticks get accounted here;
287 * the user ticks get saved up in paca->user_time_scaled to be
288 * used by account_process_tick.
290 stime_scaled = stime;
291 utime_scaled = utime;
292 if (deltascaled != stime + utime) {
294 stime_scaled = deltascaled * stime / (stime + utime);
295 utime_scaled = deltascaled - stime_scaled;
297 stime_scaled = deltascaled;
300 acct->utime_scaled += utime_scaled;
306 static unsigned long vtime_delta(struct cpu_accounting_data *acct,
307 unsigned long *stime_scaled,
308 unsigned long *steal_time)
310 unsigned long now, stime;
312 WARN_ON_ONCE(!irqs_disabled());
315 stime = now - acct->starttime;
316 acct->starttime = now;
318 *stime_scaled = vtime_delta_scaled(acct, now, stime);
320 *steal_time = calculate_stolen_time(now);
325 static void vtime_delta_kernel(struct cpu_accounting_data *acct,
326 unsigned long *stime, unsigned long *stime_scaled)
328 unsigned long steal_time;
330 *stime = vtime_delta(acct, stime_scaled, &steal_time);
331 *stime -= min(*stime, steal_time);
332 acct->steal_time += steal_time;
335 void vtime_account_kernel(struct task_struct *tsk)
337 struct cpu_accounting_data *acct = get_accounting(tsk);
338 unsigned long stime, stime_scaled;
340 vtime_delta_kernel(acct, &stime, &stime_scaled);
342 if (tsk->flags & PF_VCPU) {
343 acct->gtime += stime;
344 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
345 acct->utime_scaled += stime_scaled;
348 acct->stime += stime;
349 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
350 acct->stime_scaled += stime_scaled;
354 EXPORT_SYMBOL_GPL(vtime_account_kernel);
356 void vtime_account_idle(struct task_struct *tsk)
358 unsigned long stime, stime_scaled, steal_time;
359 struct cpu_accounting_data *acct = get_accounting(tsk);
361 stime = vtime_delta(acct, &stime_scaled, &steal_time);
362 acct->idle_time += stime + steal_time;
365 static void vtime_account_irq_field(struct cpu_accounting_data *acct,
366 unsigned long *field)
368 unsigned long stime, stime_scaled;
370 vtime_delta_kernel(acct, &stime, &stime_scaled);
372 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
373 acct->stime_scaled += stime_scaled;
377 void vtime_account_softirq(struct task_struct *tsk)
379 struct cpu_accounting_data *acct = get_accounting(tsk);
380 vtime_account_irq_field(acct, &acct->softirq_time);
383 void vtime_account_hardirq(struct task_struct *tsk)
385 struct cpu_accounting_data *acct = get_accounting(tsk);
386 vtime_account_irq_field(acct, &acct->hardirq_time);
389 static void vtime_flush_scaled(struct task_struct *tsk,
390 struct cpu_accounting_data *acct)
392 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
393 if (acct->utime_scaled)
394 tsk->utimescaled += cputime_to_nsecs(acct->utime_scaled);
395 if (acct->stime_scaled)
396 tsk->stimescaled += cputime_to_nsecs(acct->stime_scaled);
398 acct->utime_scaled = 0;
399 acct->utime_sspurr = 0;
400 acct->stime_scaled = 0;
405 * Account the whole cputime accumulated in the paca
406 * Must be called with interrupts disabled.
407 * Assumes that vtime_account_kernel/idle() has been called
408 * recently (i.e. since the last entry from usermode) so that
409 * get_paca()->user_time_scaled is up to date.
411 void vtime_flush(struct task_struct *tsk)
413 struct cpu_accounting_data *acct = get_accounting(tsk);
416 account_user_time(tsk, cputime_to_nsecs(acct->utime));
419 account_guest_time(tsk, cputime_to_nsecs(acct->gtime));
421 if (IS_ENABLED(CONFIG_PPC_SPLPAR) && acct->steal_time) {
422 account_steal_time(cputime_to_nsecs(acct->steal_time));
423 acct->steal_time = 0;
427 account_idle_time(cputime_to_nsecs(acct->idle_time));
430 account_system_index_time(tsk, cputime_to_nsecs(acct->stime),
433 if (acct->hardirq_time)
434 account_system_index_time(tsk, cputime_to_nsecs(acct->hardirq_time),
436 if (acct->softirq_time)
437 account_system_index_time(tsk, cputime_to_nsecs(acct->softirq_time),
440 vtime_flush_scaled(tsk, acct);
446 acct->hardirq_time = 0;
447 acct->softirq_time = 0;
450 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
451 #define calc_cputime_factors()
454 void __delay(unsigned long loops)
461 * TB is in error state and isn't ticking anymore.
462 * HMI handler was unable to recover from TB error.
463 * Return immediately, so that kernel won't get stuck here.
468 while (mftb() - start < loops)
473 EXPORT_SYMBOL(__delay);
475 void udelay(unsigned long usecs)
477 __delay(tb_ticks_per_usec * usecs);
479 EXPORT_SYMBOL(udelay);
482 unsigned long profile_pc(struct pt_regs *regs)
484 unsigned long pc = instruction_pointer(regs);
486 if (in_lock_functions(pc))
491 EXPORT_SYMBOL(profile_pc);
494 #ifdef CONFIG_IRQ_WORK
497 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable...
500 static inline void set_irq_work_pending_flag(void)
502 asm volatile("stb %0,%1(13)" : :
504 "i" (offsetof(struct paca_struct, irq_work_pending)));
507 static inline void clear_irq_work_pending(void)
509 asm volatile("stb %0,%1(13)" : :
511 "i" (offsetof(struct paca_struct, irq_work_pending)));
516 DEFINE_PER_CPU(u8, irq_work_pending);
518 #define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1)
519 #define test_irq_work_pending() __this_cpu_read(irq_work_pending)
520 #define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0)
522 #endif /* 32 vs 64 bit */
524 void arch_irq_work_raise(void)
527 * 64-bit code that uses irq soft-mask can just cause an immediate
528 * interrupt here that gets soft masked, if this is called under
529 * local_irq_disable(). It might be possible to prevent that happening
530 * by noticing interrupts are disabled and setting decrementer pending
531 * to be replayed when irqs are enabled. The problem there is that
532 * tracing can call irq_work_raise, including in code that does low
533 * level manipulations of irq soft-mask state (e.g., trace_hardirqs_on)
534 * which could get tangled up if we're messing with the same state
538 set_irq_work_pending_flag();
543 #else /* CONFIG_IRQ_WORK */
545 #define test_irq_work_pending() 0
546 #define clear_irq_work_pending()
548 #endif /* CONFIG_IRQ_WORK */
551 * timer_interrupt - gets called when the decrementer overflows,
552 * with interrupts disabled.
554 DEFINE_INTERRUPT_HANDLER_ASYNC(timer_interrupt)
556 struct clock_event_device *evt = this_cpu_ptr(&decrementers);
557 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb);
558 struct pt_regs *old_regs;
562 * Some implementations of hotplug will get timer interrupts while
563 * offline, just ignore these.
565 if (unlikely(!cpu_online(smp_processor_id()))) {
566 set_dec(decrementer_max);
570 /* Ensure a positive value is written to the decrementer, or else
571 * some CPUs will continue to take decrementer exceptions. When the
572 * PPC_WATCHDOG (decrementer based) is configured, keep this at most
573 * 31 bits, which is about 4 seconds on most systems, which gives
574 * the watchdog a chance of catching timer interrupt hard lockups.
576 if (IS_ENABLED(CONFIG_PPC_WATCHDOG))
579 set_dec(decrementer_max);
581 /* Conditionally hard-enable interrupts now that the DEC has been
582 * bumped to its maximum value
584 may_hard_irq_enable();
587 #if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC)
588 if (atomic_read(&ppc_n_lost_interrupts) != 0)
592 old_regs = set_irq_regs(regs);
594 trace_timer_interrupt_entry(regs);
596 if (test_irq_work_pending()) {
597 clear_irq_work_pending();
602 if (now >= *next_tb) {
604 if (evt->event_handler)
605 evt->event_handler(evt);
606 __this_cpu_inc(irq_stat.timer_irqs_event);
608 now = *next_tb - now;
609 if (now <= decrementer_max)
611 /* We may have raced with new irq work */
612 if (test_irq_work_pending())
614 __this_cpu_inc(irq_stat.timer_irqs_others);
617 trace_timer_interrupt_exit(regs);
619 set_irq_regs(old_regs);
621 EXPORT_SYMBOL(timer_interrupt);
623 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
624 void timer_broadcast_interrupt(void)
626 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb);
629 tick_receive_broadcast();
630 __this_cpu_inc(irq_stat.broadcast_irqs_event);
634 #ifdef CONFIG_SUSPEND
635 static void generic_suspend_disable_irqs(void)
637 /* Disable the decrementer, so that it doesn't interfere
641 set_dec(decrementer_max);
643 set_dec(decrementer_max);
646 static void generic_suspend_enable_irqs(void)
651 /* Overrides the weak version in kernel/power/main.c */
652 void arch_suspend_disable_irqs(void)
654 if (ppc_md.suspend_disable_irqs)
655 ppc_md.suspend_disable_irqs();
656 generic_suspend_disable_irqs();
659 /* Overrides the weak version in kernel/power/main.c */
660 void arch_suspend_enable_irqs(void)
662 generic_suspend_enable_irqs();
663 if (ppc_md.suspend_enable_irqs)
664 ppc_md.suspend_enable_irqs();
668 unsigned long long tb_to_ns(unsigned long long ticks)
670 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift;
672 EXPORT_SYMBOL_GPL(tb_to_ns);
675 * Scheduler clock - returns current time in nanosec units.
677 * Note: mulhdu(a, b) (multiply high double unsigned) returns
678 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
679 * are 64-bit unsigned numbers.
681 notrace unsigned long long sched_clock(void)
683 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
687 #ifdef CONFIG_PPC_PSERIES
690 * Running clock - attempts to give a view of time passing for a virtualised
692 * Uses the VTB register if available otherwise a next best guess.
694 unsigned long long running_clock(void)
697 * Don't read the VTB as a host since KVM does not switch in host
698 * timebase into the VTB when it takes a guest off the CPU, reading the
699 * VTB would result in reading 'last switched out' guest VTB.
701 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it
702 * would be unsafe to rely only on the #ifdef above.
704 if (firmware_has_feature(FW_FEATURE_LPAR) &&
705 cpu_has_feature(CPU_FTR_ARCH_207S))
706 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
709 * This is a next best approximation without a VTB.
710 * On a host which is running bare metal there should never be any stolen
711 * time and on a host which doesn't do any virtualisation TB *should* equal
712 * VTB so it makes no difference anyway.
714 return local_clock() - kcpustat_this_cpu->cpustat[CPUTIME_STEAL];
718 static int __init get_freq(char *name, int cells, unsigned long *val)
720 struct device_node *cpu;
724 /* The cpu node should have timebase and clock frequency properties */
725 cpu = of_find_node_by_type(NULL, "cpu");
728 fp = of_get_property(cpu, name, NULL);
731 *val = of_read_ulong(fp, cells);
740 static void start_cpu_decrementer(void)
742 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
745 /* Clear any pending timer interrupts */
746 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS);
748 tcr = mfspr(SPRN_TCR);
750 * The watchdog may have already been enabled by u-boot. So leave
751 * TRC[WP] (Watchdog Period) alone.
753 tcr &= TCR_WP_MASK; /* Clear all bits except for TCR[WP] */
754 tcr |= TCR_DIE; /* Enable decrementer */
755 mtspr(SPRN_TCR, tcr);
759 void __init generic_calibrate_decr(void)
761 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */
763 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) &&
764 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) {
766 printk(KERN_ERR "WARNING: Estimating decrementer frequency "
770 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */
772 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) &&
773 !get_freq("clock-frequency", 1, &ppc_proc_freq)) {
775 printk(KERN_ERR "WARNING: Estimating processor frequency "
780 int update_persistent_clock64(struct timespec64 now)
784 if (!ppc_md.set_rtc_time)
787 rtc_time64_to_tm(now.tv_sec + 1 + timezone_offset, &tm);
789 return ppc_md.set_rtc_time(&tm);
792 static void __read_persistent_clock(struct timespec64 *ts)
795 static int first = 1;
798 /* XXX this is a litle fragile but will work okay in the short term */
801 if (ppc_md.time_init)
802 timezone_offset = ppc_md.time_init();
804 /* get_boot_time() isn't guaranteed to be safe to call late */
805 if (ppc_md.get_boot_time) {
806 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset;
810 if (!ppc_md.get_rtc_time) {
814 ppc_md.get_rtc_time(&tm);
816 ts->tv_sec = rtc_tm_to_time64(&tm);
819 void read_persistent_clock64(struct timespec64 *ts)
821 __read_persistent_clock(ts);
823 /* Sanitize it in case real time clock is set below EPOCH */
824 if (ts->tv_sec < 0) {
831 /* clocksource code */
832 static notrace u64 timebase_read(struct clocksource *cs)
834 return (u64)get_tb();
837 static void __init clocksource_init(void)
839 struct clocksource *clock = &clocksource_timebase;
841 if (clocksource_register_hz(clock, tb_ticks_per_sec)) {
842 printk(KERN_ERR "clocksource: %s is already registered\n",
847 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n",
848 clock->name, clock->mult, clock->shift);
851 static int decrementer_set_next_event(unsigned long evt,
852 struct clock_event_device *dev)
854 __this_cpu_write(decrementers_next_tb, get_tb() + evt);
857 /* We may have raced with new irq work */
858 if (test_irq_work_pending())
864 static int decrementer_shutdown(struct clock_event_device *dev)
866 decrementer_set_next_event(decrementer_max, dev);
870 static void register_decrementer_clockevent(int cpu)
872 struct clock_event_device *dec = &per_cpu(decrementers, cpu);
874 *dec = decrementer_clockevent;
875 dec->cpumask = cpumask_of(cpu);
877 clockevents_config_and_register(dec, ppc_tb_freq, 2, decrementer_max);
879 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n",
880 dec->name, dec->mult, dec->shift, cpu);
882 /* Set values for KVM, see kvm_emulate_dec() */
883 decrementer_clockevent.mult = dec->mult;
884 decrementer_clockevent.shift = dec->shift;
887 static void enable_large_decrementer(void)
889 if (!cpu_has_feature(CPU_FTR_ARCH_300))
892 if (decrementer_max <= DECREMENTER_DEFAULT_MAX)
896 * If we're running as the hypervisor we need to enable the LD manually
897 * otherwise firmware should have done it for us.
899 if (cpu_has_feature(CPU_FTR_HVMODE))
900 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD);
903 static void __init set_decrementer_max(void)
905 struct device_node *cpu;
908 /* Prior to ISAv3 the decrementer is always 32 bit */
909 if (!cpu_has_feature(CPU_FTR_ARCH_300))
912 cpu = of_find_node_by_type(NULL, "cpu");
914 if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) {
915 if (bits > 64 || bits < 32) {
916 pr_warn("time_init: firmware supplied invalid ibm,dec-bits");
920 /* calculate the signed maximum given this many bits */
921 decrementer_max = (1ul << (bits - 1)) - 1;
926 pr_info("time_init: %u bit decrementer (max: %llx)\n",
927 bits, decrementer_max);
930 static void __init init_decrementer_clockevent(void)
932 register_decrementer_clockevent(smp_processor_id());
935 void secondary_cpu_time_init(void)
937 /* Enable and test the large decrementer for this cpu */
938 enable_large_decrementer();
940 /* Start the decrementer on CPUs that have manual control
943 start_cpu_decrementer();
945 /* FIME: Should make unrelatred change to move snapshot_timebase
947 register_decrementer_clockevent(smp_processor_id());
950 /* This function is only called on the boot processor */
951 void __init time_init(void)
953 struct div_result res;
957 /* Normal PowerPC with timebase register */
958 ppc_md.calibrate_decr();
959 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n",
960 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
961 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n",
962 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
964 tb_ticks_per_jiffy = ppc_tb_freq / HZ;
965 tb_ticks_per_sec = ppc_tb_freq;
966 tb_ticks_per_usec = ppc_tb_freq / 1000000;
967 calc_cputime_factors();
970 * Compute scale factor for sched_clock.
971 * The calibrate_decr() function has set tb_ticks_per_sec,
972 * which is the timebase frequency.
973 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
974 * the 128-bit result as a 64.64 fixed-point number.
975 * We then shift that number right until it is less than 1.0,
976 * giving us the scale factor and shift count to use in
979 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res);
980 scale = res.result_low;
981 for (shift = 0; res.result_high != 0; ++shift) {
982 scale = (scale >> 1) | (res.result_high << 63);
983 res.result_high >>= 1;
985 tb_to_ns_scale = scale;
986 tb_to_ns_shift = shift;
987 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
990 /* If platform provided a timezone (pmac), we correct the time */
991 if (timezone_offset) {
992 sys_tz.tz_minuteswest = -timezone_offset / 60;
993 sys_tz.tz_dsttime = 0;
996 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
998 /* initialise and enable the large decrementer (if we have one) */
999 set_decrementer_max();
1000 enable_large_decrementer();
1002 /* Start the decrementer on CPUs that have manual control
1005 start_cpu_decrementer();
1007 /* Register the clocksource */
1010 init_decrementer_clockevent();
1011 tick_setup_hrtimer_broadcast();
1014 enable_sched_clock_irqtime();
1018 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1021 void div128_by_32(u64 dividend_high, u64 dividend_low,
1022 unsigned divisor, struct div_result *dr)
1024 unsigned long a, b, c, d;
1025 unsigned long w, x, y, z;
1028 a = dividend_high >> 32;
1029 b = dividend_high & 0xffffffff;
1030 c = dividend_low >> 32;
1031 d = dividend_low & 0xffffffff;
1034 ra = ((u64)(a - (w * divisor)) << 32) + b;
1036 rb = ((u64) do_div(ra, divisor) << 32) + c;
1039 rc = ((u64) do_div(rb, divisor) << 32) + d;
1042 do_div(rc, divisor);
1045 dr->result_high = ((u64)w << 32) + x;
1046 dr->result_low = ((u64)y << 32) + z;
1050 /* We don't need to calibrate delay, we use the CPU timebase for that */
1051 void calibrate_delay(void)
1053 /* Some generic code (such as spinlock debug) use loops_per_jiffy
1054 * as the number of __delay(1) in a jiffy, so make it so
1056 loops_per_jiffy = tb_ticks_per_jiffy;
1059 #if IS_ENABLED(CONFIG_RTC_DRV_GENERIC)
1060 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
1062 ppc_md.get_rtc_time(tm);
1066 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)
1068 if (!ppc_md.set_rtc_time)
1071 if (ppc_md.set_rtc_time(tm) < 0)
1077 static const struct rtc_class_ops rtc_generic_ops = {
1078 .read_time = rtc_generic_get_time,
1079 .set_time = rtc_generic_set_time,
1082 static int __init rtc_init(void)
1084 struct platform_device *pdev;
1086 if (!ppc_md.get_rtc_time)
1089 pdev = platform_device_register_data(NULL, "rtc-generic", -1,
1091 sizeof(rtc_generic_ops));
1093 return PTR_ERR_OR_ZERO(pdev);
1096 device_initcall(rtc_init);