2 * Common time routines among all ppc machines.
4 * Written by Cort Dougan (cort@cs.nmt.edu) to merge
5 * Paul Mackerras' version and mine for PReP and Pmac.
6 * MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net).
7 * Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com)
9 * First round of bugfixes by Gabriel Paubert (paubert@iram.es)
10 * to make clock more stable (2.4.0-test5). The only thing
11 * that this code assumes is that the timebases have been synchronized
12 * by firmware on SMP and are never stopped (never do sleep
13 * on SMP then, nap and doze are OK).
15 * Speeded up do_gettimeofday by getting rid of references to
16 * xtime (which required locks for consistency). (mikejc@us.ibm.com)
18 * TODO (not necessarily in this file):
19 * - improve precision and reproducibility of timebase frequency
20 * measurement at boot time.
21 * - for astronomical applications: add a new function to get
22 * non ambiguous timestamps even around leap seconds. This needs
23 * a new timestamp format and a good name.
25 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
26 * "A Kernel Model for Precision Timekeeping" by Dave Mills
28 * This program is free software; you can redistribute it and/or
29 * modify it under the terms of the GNU General Public License
30 * as published by the Free Software Foundation; either version
31 * 2 of the License, or (at your option) any later version.
34 #include <linux/errno.h>
35 #include <linux/export.h>
36 #include <linux/sched.h>
37 #include <linux/kernel.h>
38 #include <linux/param.h>
39 #include <linux/string.h>
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>
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>
71 #include <asm/div64.h>
73 #include <asm/vdso_datapage.h>
74 #include <asm/firmware.h>
75 #include <asm/cputime.h>
76 #include <asm/asm-prototypes.h>
78 /* powerpc clocksource/clockevent code */
80 #include <linux/clockchips.h>
81 #include <linux/timekeeper_internal.h>
83 static cycle_t rtc_read(struct clocksource *);
84 static struct clocksource clocksource_rtc = {
87 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
88 .mask = CLOCKSOURCE_MASK(64),
92 static cycle_t timebase_read(struct clocksource *);
93 static struct clocksource clocksource_timebase = {
96 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
97 .mask = CLOCKSOURCE_MASK(64),
98 .read = timebase_read,
101 #define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF
102 u64 decrementer_max = DECREMENTER_DEFAULT_MAX;
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);
108 struct clock_event_device decrementer_clockevent = {
109 .name = "decrementer",
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,
118 EXPORT_SYMBOL(decrementer_clockevent);
120 DEFINE_PER_CPU(u64, decrementers_next_tb);
121 static DEFINE_PER_CPU(struct clock_event_device, decrementers);
123 #define XSEC_PER_SEC (1024*1024)
126 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
128 /* compute ((xsec << 12) * max) >> 32 */
129 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
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 */
138 DEFINE_SPINLOCK(rtc_lock);
139 EXPORT_SYMBOL_GPL(rtc_lock);
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;
145 extern struct timezone sys_tz;
146 static long timezone_offset;
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);
153 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
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.
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);
170 cputime_t cputime_one_jiffy;
172 #ifdef CONFIG_PPC_SPLPAR
173 void (*dtl_consumer)(struct dtl_entry *, u64);
177 #define get_accounting(tsk) (&get_paca()->accounting)
179 #define get_accounting(tsk) (&task_thread_info(tsk)->accounting)
182 static void calc_cputime_factors(void)
184 struct div_result res;
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;
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.
200 static unsigned long read_spurr(unsigned long tb)
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);
209 #ifdef CONFIG_PPC_SPLPAR
212 * Scan the dispatch trace log and count up the stolen time.
213 * Should be called with interrupts disabled.
215 static u64 scan_dispatch_log(u64 stop_tb)
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;
228 if (i == be64_to_cpu(vpa->dtl_idx))
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);
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);
244 dtl_consumer(dtl, i);
249 dtl = local_paca->dispatch_log;
251 local_paca->dtl_ridx = i;
252 local_paca->dtl_curr = dtl;
257 * Accumulate stolen time by scanning the dispatch trace log.
258 * Called on entry from user mode.
260 void accumulate_stolen_time(void)
263 u8 save_soft_enabled = local_paca->soft_enabled;
264 struct cpu_accounting_data *acct = &local_paca->accounting;
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
272 local_paca->soft_enabled = 0;
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;
280 local_paca->soft_enabled = save_soft_enabled;
283 static inline u64 calculate_stolen_time(u64 stop_tb)
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;
292 stolen += get_paca()->stolen_time;
293 get_paca()->stolen_time = 0;
297 #else /* CONFIG_PPC_SPLPAR */
298 static inline u64 calculate_stolen_time(u64 stop_tb)
303 #endif /* CONFIG_PPC_SPLPAR */
306 * Account time for a transition between system, hard irq
309 static unsigned long vtime_delta(struct task_struct *tsk,
310 unsigned long *sys_scaled,
311 unsigned long *stolen)
313 unsigned long now, nowscaled, deltascaled;
314 unsigned long udelta, delta, user_scaled;
315 struct cpu_accounting_data *acct = get_accounting(tsk);
317 WARN_ON_ONCE(!irqs_disabled());
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;
326 *stolen = calculate_stolen_time(now);
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;
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.
344 user_scaled = udelta;
345 if (deltascaled != delta + udelta) {
347 *sys_scaled = deltascaled * delta / (delta + udelta);
348 user_scaled = deltascaled - *sys_scaled;
350 *sys_scaled = deltascaled;
353 acct->user_time_scaled += user_scaled;
358 void vtime_account_system(struct task_struct *tsk)
360 unsigned long delta, sys_scaled, stolen;
362 delta = vtime_delta(tsk, &sys_scaled, &stolen);
363 account_system_time(tsk, 0, delta, sys_scaled);
365 account_steal_time(stolen);
367 EXPORT_SYMBOL_GPL(vtime_account_system);
369 void vtime_account_idle(struct task_struct *tsk)
371 unsigned long delta, sys_scaled, stolen;
373 delta = vtime_delta(tsk, &sys_scaled, &stolen);
374 account_idle_time(delta + stolen);
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.
386 void vtime_account_user(struct task_struct *tsk)
388 cputime_t utime, utimescaled;
389 struct cpu_accounting_data *acct = get_accounting(tsk);
391 utime = acct->user_time;
392 utimescaled = acct->user_time_scaled;
394 acct->user_time_scaled = 0;
395 acct->utime_sspurr = 0;
396 account_user_time(tsk, utime, utimescaled);
401 * Called from the context switch with interrupts disabled, to charge all
402 * accumulated times to the current process, and to prepare accounting on
405 void arch_vtime_task_switch(struct task_struct *prev)
407 struct cpu_accounting_data *acct = get_accounting(current);
409 acct->starttime = get_accounting(prev)->starttime;
410 acct->system_time = 0;
413 #endif /* CONFIG_PPC32 */
415 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
416 #define calc_cputime_factors()
419 void __delay(unsigned long loops)
427 /* the RTCL register wraps at 1000000000 */
428 diff = get_rtcl() - start;
431 } while (diff < loops);
434 while (get_tbl() - start < loops)
439 EXPORT_SYMBOL(__delay);
441 void udelay(unsigned long usecs)
443 __delay(tb_ticks_per_usec * usecs);
445 EXPORT_SYMBOL(udelay);
448 unsigned long profile_pc(struct pt_regs *regs)
450 unsigned long pc = instruction_pointer(regs);
452 if (in_lock_functions(pc))
457 EXPORT_SYMBOL(profile_pc);
460 #ifdef CONFIG_IRQ_WORK
463 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable...
466 static inline unsigned long test_irq_work_pending(void)
470 asm volatile("lbz %0,%1(13)"
472 : "i" (offsetof(struct paca_struct, irq_work_pending)));
476 static inline void set_irq_work_pending_flag(void)
478 asm volatile("stb %0,%1(13)" : :
480 "i" (offsetof(struct paca_struct, irq_work_pending)));
483 static inline void clear_irq_work_pending(void)
485 asm volatile("stb %0,%1(13)" : :
487 "i" (offsetof(struct paca_struct, irq_work_pending)));
492 DEFINE_PER_CPU(u8, irq_work_pending);
494 #define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1)
495 #define test_irq_work_pending() __this_cpu_read(irq_work_pending)
496 #define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0)
498 #endif /* 32 vs 64 bit */
500 void arch_irq_work_raise(void)
503 set_irq_work_pending_flag();
508 #else /* CONFIG_IRQ_WORK */
510 #define test_irq_work_pending() 0
511 #define clear_irq_work_pending()
513 #endif /* CONFIG_IRQ_WORK */
515 static void __timer_interrupt(void)
517 struct pt_regs *regs = get_irq_regs();
518 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb);
519 struct clock_event_device *evt = this_cpu_ptr(&decrementers);
522 trace_timer_interrupt_entry(regs);
524 if (test_irq_work_pending()) {
525 clear_irq_work_pending();
529 now = get_tb_or_rtc();
530 if (now >= *next_tb) {
532 if (evt->event_handler)
533 evt->event_handler(evt);
534 __this_cpu_inc(irq_stat.timer_irqs_event);
536 now = *next_tb - now;
537 if (now <= decrementer_max)
539 /* We may have raced with new irq work */
540 if (test_irq_work_pending())
542 __this_cpu_inc(irq_stat.timer_irqs_others);
546 /* collect purr register values often, for accurate calculations */
547 if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
548 struct cpu_usage *cu = this_cpu_ptr(&cpu_usage_array);
549 cu->current_tb = mfspr(SPRN_PURR);
553 trace_timer_interrupt_exit(regs);
557 * timer_interrupt - gets called when the decrementer overflows,
558 * with interrupts disabled.
560 void timer_interrupt(struct pt_regs * regs)
562 struct pt_regs *old_regs;
563 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb);
565 /* Ensure a positive value is written to the decrementer, or else
566 * some CPUs will continue to take decrementer exceptions.
568 set_dec(decrementer_max);
570 /* Some implementations of hotplug will get timer interrupts while
571 * offline, just ignore these and we also need to set
572 * decrementers_next_tb as MAX to make sure __check_irq_replay
573 * don't replay timer interrupt when return, otherwise we'll trap
576 if (!cpu_online(smp_processor_id())) {
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);
597 set_irq_regs(old_regs);
599 EXPORT_SYMBOL(timer_interrupt);
602 * Hypervisor decrementer interrupts shouldn't occur but are sometimes
603 * left pending on exit from a KVM guest. We don't need to do anything
604 * to clear them, as they are edge-triggered.
606 void hdec_interrupt(struct pt_regs *regs)
610 #ifdef CONFIG_SUSPEND
611 static void generic_suspend_disable_irqs(void)
613 /* Disable the decrementer, so that it doesn't interfere
617 set_dec(decrementer_max);
619 set_dec(decrementer_max);
622 static void generic_suspend_enable_irqs(void)
627 /* Overrides the weak version in kernel/power/main.c */
628 void arch_suspend_disable_irqs(void)
630 if (ppc_md.suspend_disable_irqs)
631 ppc_md.suspend_disable_irqs();
632 generic_suspend_disable_irqs();
635 /* Overrides the weak version in kernel/power/main.c */
636 void arch_suspend_enable_irqs(void)
638 generic_suspend_enable_irqs();
639 if (ppc_md.suspend_enable_irqs)
640 ppc_md.suspend_enable_irqs();
644 unsigned long long tb_to_ns(unsigned long long ticks)
646 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift;
648 EXPORT_SYMBOL_GPL(tb_to_ns);
651 * Scheduler clock - returns current time in nanosec units.
653 * Note: mulhdu(a, b) (multiply high double unsigned) returns
654 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
655 * are 64-bit unsigned numbers.
657 unsigned long long sched_clock(void)
661 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
665 #ifdef CONFIG_PPC_PSERIES
668 * Running clock - attempts to give a view of time passing for a virtualised
670 * Uses the VTB register if available otherwise a next best guess.
672 unsigned long long running_clock(void)
675 * Don't read the VTB as a host since KVM does not switch in host
676 * timebase into the VTB when it takes a guest off the CPU, reading the
677 * VTB would result in reading 'last switched out' guest VTB.
679 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it
680 * would be unsafe to rely only on the #ifdef above.
682 if (firmware_has_feature(FW_FEATURE_LPAR) &&
683 cpu_has_feature(CPU_FTR_ARCH_207S))
684 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
687 * This is a next best approximation without a VTB.
688 * On a host which is running bare metal there should never be any stolen
689 * time and on a host which doesn't do any virtualisation TB *should* equal
690 * VTB so it makes no difference anyway.
692 return local_clock() - cputime_to_nsecs(kcpustat_this_cpu->cpustat[CPUTIME_STEAL]);
696 static int __init get_freq(char *name, int cells, unsigned long *val)
698 struct device_node *cpu;
702 /* The cpu node should have timebase and clock frequency properties */
703 cpu = of_find_node_by_type(NULL, "cpu");
706 fp = of_get_property(cpu, name, NULL);
709 *val = of_read_ulong(fp, cells);
718 static void start_cpu_decrementer(void)
720 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
721 /* Clear any pending timer interrupts */
722 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS);
724 /* Enable decrementer interrupt */
725 mtspr(SPRN_TCR, TCR_DIE);
726 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */
729 void __init generic_calibrate_decr(void)
731 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */
733 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) &&
734 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) {
736 printk(KERN_ERR "WARNING: Estimating decrementer frequency "
740 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */
742 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) &&
743 !get_freq("clock-frequency", 1, &ppc_proc_freq)) {
745 printk(KERN_ERR "WARNING: Estimating processor frequency "
750 int update_persistent_clock(struct timespec now)
754 if (!ppc_md.set_rtc_time)
757 to_tm(now.tv_sec + 1 + timezone_offset, &tm);
761 return ppc_md.set_rtc_time(&tm);
764 static void __read_persistent_clock(struct timespec *ts)
767 static int first = 1;
770 /* XXX this is a litle fragile but will work okay in the short term */
773 if (ppc_md.time_init)
774 timezone_offset = ppc_md.time_init();
776 /* get_boot_time() isn't guaranteed to be safe to call late */
777 if (ppc_md.get_boot_time) {
778 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset;
782 if (!ppc_md.get_rtc_time) {
786 ppc_md.get_rtc_time(&tm);
788 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
789 tm.tm_hour, tm.tm_min, tm.tm_sec);
792 void read_persistent_clock(struct timespec *ts)
794 __read_persistent_clock(ts);
796 /* Sanitize it in case real time clock is set below EPOCH */
797 if (ts->tv_sec < 0) {
804 /* clocksource code */
805 static cycle_t rtc_read(struct clocksource *cs)
807 return (cycle_t)get_rtc();
810 static cycle_t timebase_read(struct clocksource *cs)
812 return (cycle_t)get_tb();
815 void update_vsyscall_old(struct timespec *wall_time, struct timespec *wtm,
816 struct clocksource *clock, u32 mult, cycle_t cycle_last)
818 u64 new_tb_to_xs, new_stamp_xsec;
821 if (clock != &clocksource_timebase)
824 /* Make userspace gettimeofday spin until we're done. */
825 ++vdso_data->tb_update_count;
828 /* 19342813113834067 ~= 2^(20+64) / 1e9 */
829 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift);
830 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC;
831 do_div(new_stamp_xsec, 1000000000);
832 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC;
834 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC);
835 /* this is tv_nsec / 1e9 as a 0.32 fraction */
836 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32;
839 * tb_update_count is used to allow the userspace gettimeofday code
840 * to assure itself that it sees a consistent view of the tb_to_xs and
841 * stamp_xsec variables. It reads the tb_update_count, then reads
842 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
843 * the two values of tb_update_count match and are even then the
844 * tb_to_xs and stamp_xsec values are consistent. If not, then it
845 * loops back and reads them again until this criteria is met.
846 * We expect the caller to have done the first increment of
847 * vdso_data->tb_update_count already.
849 vdso_data->tb_orig_stamp = cycle_last;
850 vdso_data->stamp_xsec = new_stamp_xsec;
851 vdso_data->tb_to_xs = new_tb_to_xs;
852 vdso_data->wtom_clock_sec = wtm->tv_sec;
853 vdso_data->wtom_clock_nsec = wtm->tv_nsec;
854 vdso_data->stamp_xtime = *wall_time;
855 vdso_data->stamp_sec_fraction = frac_sec;
857 ++(vdso_data->tb_update_count);
860 void update_vsyscall_tz(void)
862 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
863 vdso_data->tz_dsttime = sys_tz.tz_dsttime;
866 static void __init clocksource_init(void)
868 struct clocksource *clock;
871 clock = &clocksource_rtc;
873 clock = &clocksource_timebase;
875 if (clocksource_register_hz(clock, tb_ticks_per_sec)) {
876 printk(KERN_ERR "clocksource: %s is already registered\n",
881 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n",
882 clock->name, clock->mult, clock->shift);
885 static int decrementer_set_next_event(unsigned long evt,
886 struct clock_event_device *dev)
888 __this_cpu_write(decrementers_next_tb, get_tb_or_rtc() + evt);
891 /* We may have raced with new irq work */
892 if (test_irq_work_pending())
898 static int decrementer_shutdown(struct clock_event_device *dev)
900 decrementer_set_next_event(decrementer_max, dev);
904 /* Interrupt handler for the timer broadcast IPI */
905 void tick_broadcast_ipi_handler(void)
907 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb);
909 *next_tb = get_tb_or_rtc();
913 static void register_decrementer_clockevent(int cpu)
915 struct clock_event_device *dec = &per_cpu(decrementers, cpu);
917 *dec = decrementer_clockevent;
918 dec->cpumask = cpumask_of(cpu);
920 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n",
921 dec->name, dec->mult, dec->shift, cpu);
923 clockevents_register_device(dec);
926 static void enable_large_decrementer(void)
928 if (!cpu_has_feature(CPU_FTR_ARCH_300))
931 if (decrementer_max <= DECREMENTER_DEFAULT_MAX)
935 * If we're running as the hypervisor we need to enable the LD manually
936 * otherwise firmware should have done it for us.
938 if (cpu_has_feature(CPU_FTR_HVMODE))
939 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD);
942 static void __init set_decrementer_max(void)
944 struct device_node *cpu;
947 /* Prior to ISAv3 the decrementer is always 32 bit */
948 if (!cpu_has_feature(CPU_FTR_ARCH_300))
951 cpu = of_find_node_by_type(NULL, "cpu");
953 if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) {
954 if (bits > 64 || bits < 32) {
955 pr_warn("time_init: firmware supplied invalid ibm,dec-bits");
959 /* calculate the signed maximum given this many bits */
960 decrementer_max = (1ul << (bits - 1)) - 1;
965 pr_info("time_init: %u bit decrementer (max: %llx)\n",
966 bits, decrementer_max);
969 static void __init init_decrementer_clockevent(void)
971 int cpu = smp_processor_id();
973 clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4);
975 decrementer_clockevent.max_delta_ns =
976 clockevent_delta2ns(decrementer_max, &decrementer_clockevent);
977 decrementer_clockevent.min_delta_ns =
978 clockevent_delta2ns(2, &decrementer_clockevent);
980 register_decrementer_clockevent(cpu);
983 void secondary_cpu_time_init(void)
985 /* Enable and test the large decrementer for this cpu */
986 enable_large_decrementer();
988 /* Start the decrementer on CPUs that have manual control
991 start_cpu_decrementer();
993 /* FIME: Should make unrelatred change to move snapshot_timebase
995 register_decrementer_clockevent(smp_processor_id());
998 /* This function is only called on the boot processor */
999 void __init time_init(void)
1001 struct div_result res;
1006 /* 601 processor: dec counts down by 128 every 128ns */
1007 ppc_tb_freq = 1000000000;
1009 /* Normal PowerPC with timebase register */
1010 ppc_md.calibrate_decr();
1011 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n",
1012 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
1013 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n",
1014 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
1017 tb_ticks_per_jiffy = ppc_tb_freq / HZ;
1018 tb_ticks_per_sec = ppc_tb_freq;
1019 tb_ticks_per_usec = ppc_tb_freq / 1000000;
1020 calc_cputime_factors();
1021 setup_cputime_one_jiffy();
1024 * Compute scale factor for sched_clock.
1025 * The calibrate_decr() function has set tb_ticks_per_sec,
1026 * which is the timebase frequency.
1027 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
1028 * the 128-bit result as a 64.64 fixed-point number.
1029 * We then shift that number right until it is less than 1.0,
1030 * giving us the scale factor and shift count to use in
1033 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res);
1034 scale = res.result_low;
1035 for (shift = 0; res.result_high != 0; ++shift) {
1036 scale = (scale >> 1) | (res.result_high << 63);
1037 res.result_high >>= 1;
1039 tb_to_ns_scale = scale;
1040 tb_to_ns_shift = shift;
1041 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
1042 boot_tb = get_tb_or_rtc();
1044 /* If platform provided a timezone (pmac), we correct the time */
1045 if (timezone_offset) {
1046 sys_tz.tz_minuteswest = -timezone_offset / 60;
1047 sys_tz.tz_dsttime = 0;
1050 vdso_data->tb_update_count = 0;
1051 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
1053 /* initialise and enable the large decrementer (if we have one) */
1054 set_decrementer_max();
1055 enable_large_decrementer();
1057 /* Start the decrementer on CPUs that have manual control
1060 start_cpu_decrementer();
1062 /* Register the clocksource */
1065 init_decrementer_clockevent();
1066 tick_setup_hrtimer_broadcast();
1068 #ifdef CONFIG_COMMON_CLK
1075 #define STARTOFTIME 1970
1076 #define SECDAY 86400L
1077 #define SECYR (SECDAY * 365)
1078 #define leapyear(year) ((year) % 4 == 0 && \
1079 ((year) % 100 != 0 || (year) % 400 == 0))
1080 #define days_in_year(a) (leapyear(a) ? 366 : 365)
1081 #define days_in_month(a) (month_days[(a) - 1])
1083 static int month_days[12] = {
1084 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
1087 void to_tm(int tim, struct rtc_time * tm)
1090 register long hms, day;
1095 /* Hours, minutes, seconds are easy */
1096 tm->tm_hour = hms / 3600;
1097 tm->tm_min = (hms % 3600) / 60;
1098 tm->tm_sec = (hms % 3600) % 60;
1100 /* Number of years in days */
1101 for (i = STARTOFTIME; day >= days_in_year(i); i++)
1102 day -= days_in_year(i);
1105 /* Number of months in days left */
1106 if (leapyear(tm->tm_year))
1107 days_in_month(FEBRUARY) = 29;
1108 for (i = 1; day >= days_in_month(i); i++)
1109 day -= days_in_month(i);
1110 days_in_month(FEBRUARY) = 28;
1113 /* Days are what is left over (+1) from all that. */
1114 tm->tm_mday = day + 1;
1117 * No-one uses the day of the week.
1121 EXPORT_SYMBOL(to_tm);
1124 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1127 void div128_by_32(u64 dividend_high, u64 dividend_low,
1128 unsigned divisor, struct div_result *dr)
1130 unsigned long a, b, c, d;
1131 unsigned long w, x, y, z;
1134 a = dividend_high >> 32;
1135 b = dividend_high & 0xffffffff;
1136 c = dividend_low >> 32;
1137 d = dividend_low & 0xffffffff;
1140 ra = ((u64)(a - (w * divisor)) << 32) + b;
1142 rb = ((u64) do_div(ra, divisor) << 32) + c;
1145 rc = ((u64) do_div(rb, divisor) << 32) + d;
1148 do_div(rc, divisor);
1151 dr->result_high = ((u64)w << 32) + x;
1152 dr->result_low = ((u64)y << 32) + z;
1156 /* We don't need to calibrate delay, we use the CPU timebase for that */
1157 void calibrate_delay(void)
1159 /* Some generic code (such as spinlock debug) use loops_per_jiffy
1160 * as the number of __delay(1) in a jiffy, so make it so
1162 loops_per_jiffy = tb_ticks_per_jiffy;
1165 #if IS_ENABLED(CONFIG_RTC_DRV_GENERIC)
1166 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
1168 ppc_md.get_rtc_time(tm);
1169 return rtc_valid_tm(tm);
1172 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)
1174 if (!ppc_md.set_rtc_time)
1177 if (ppc_md.set_rtc_time(tm) < 0)
1183 static const struct rtc_class_ops rtc_generic_ops = {
1184 .read_time = rtc_generic_get_time,
1185 .set_time = rtc_generic_set_time,
1188 static int __init rtc_init(void)
1190 struct platform_device *pdev;
1192 if (!ppc_md.get_rtc_time)
1195 pdev = platform_device_register_data(NULL, "rtc-generic", -1,
1197 sizeof(rtc_generic_ops));
1199 return PTR_ERR_OR_ZERO(pdev);
1202 device_initcall(rtc_init);