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/init.h>
46 #include <linux/profile.h>
47 #include <linux/cpu.h>
48 #include <linux/security.h>
49 #include <linux/percpu.h>
50 #include <linux/rtc.h>
51 #include <linux/jiffies.h>
52 #include <linux/posix-timers.h>
53 #include <linux/irq.h>
54 #include <linux/delay.h>
55 #include <linux/irq_work.h>
56 #include <asm/trace.h>
59 #include <asm/processor.h>
60 #include <asm/nvram.h>
61 #include <asm/cache.h>
62 #include <asm/machdep.h>
63 #include <asm/uaccess.h>
67 #include <asm/div64.h>
69 #include <asm/vdso_datapage.h>
70 #include <asm/firmware.h>
71 #include <asm/cputime.h>
73 /* powerpc clocksource/clockevent code */
75 #include <linux/clockchips.h>
76 #include <linux/clocksource.h>
78 static cycle_t rtc_read(struct clocksource *);
79 static struct clocksource clocksource_rtc = {
82 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
83 .mask = CLOCKSOURCE_MASK(64),
87 static cycle_t timebase_read(struct clocksource *);
88 static struct clocksource clocksource_timebase = {
91 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
92 .mask = CLOCKSOURCE_MASK(64),
93 .read = timebase_read,
96 #define DECREMENTER_MAX 0x7fffffff
98 static int decrementer_set_next_event(unsigned long evt,
99 struct clock_event_device *dev);
100 static void decrementer_set_mode(enum clock_event_mode mode,
101 struct clock_event_device *dev);
103 static struct clock_event_device decrementer_clockevent = {
104 .name = "decrementer",
107 .set_next_event = decrementer_set_next_event,
108 .set_mode = decrementer_set_mode,
109 .features = CLOCK_EVT_FEAT_ONESHOT,
112 DEFINE_PER_CPU(u64, decrementers_next_tb);
113 static DEFINE_PER_CPU(struct clock_event_device, decrementers);
115 #define XSEC_PER_SEC (1024*1024)
118 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
120 /* compute ((xsec << 12) * max) >> 32 */
121 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
124 unsigned long tb_ticks_per_jiffy;
125 unsigned long tb_ticks_per_usec = 100; /* sane default */
126 EXPORT_SYMBOL(tb_ticks_per_usec);
127 unsigned long tb_ticks_per_sec;
128 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
130 DEFINE_SPINLOCK(rtc_lock);
131 EXPORT_SYMBOL_GPL(rtc_lock);
133 static u64 tb_to_ns_scale __read_mostly;
134 static unsigned tb_to_ns_shift __read_mostly;
135 static u64 boot_tb __read_mostly;
137 extern struct timezone sys_tz;
138 static long timezone_offset;
140 unsigned long ppc_proc_freq;
141 EXPORT_SYMBOL_GPL(ppc_proc_freq);
142 unsigned long ppc_tb_freq;
143 EXPORT_SYMBOL_GPL(ppc_tb_freq);
145 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
147 * Factors for converting from cputime_t (timebase ticks) to
148 * jiffies, microseconds, seconds, and clock_t (1/USER_HZ seconds).
149 * These are all stored as 0.64 fixed-point binary fractions.
151 u64 __cputime_jiffies_factor;
152 EXPORT_SYMBOL(__cputime_jiffies_factor);
153 u64 __cputime_usec_factor;
154 EXPORT_SYMBOL(__cputime_usec_factor);
155 u64 __cputime_sec_factor;
156 EXPORT_SYMBOL(__cputime_sec_factor);
157 u64 __cputime_clockt_factor;
158 EXPORT_SYMBOL(__cputime_clockt_factor);
159 DEFINE_PER_CPU(unsigned long, cputime_last_delta);
160 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta);
162 cputime_t cputime_one_jiffy;
164 void (*dtl_consumer)(struct dtl_entry *, u64);
166 static void calc_cputime_factors(void)
168 struct div_result res;
170 div128_by_32(HZ, 0, tb_ticks_per_sec, &res);
171 __cputime_jiffies_factor = res.result_low;
172 div128_by_32(1000000, 0, tb_ticks_per_sec, &res);
173 __cputime_usec_factor = res.result_low;
174 div128_by_32(1, 0, tb_ticks_per_sec, &res);
175 __cputime_sec_factor = res.result_low;
176 div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res);
177 __cputime_clockt_factor = res.result_low;
181 * Read the SPURR on systems that have it, otherwise the PURR,
182 * or if that doesn't exist return the timebase value passed in.
184 static u64 read_spurr(u64 tb)
186 if (cpu_has_feature(CPU_FTR_SPURR))
187 return mfspr(SPRN_SPURR);
188 if (cpu_has_feature(CPU_FTR_PURR))
189 return mfspr(SPRN_PURR);
193 #ifdef CONFIG_PPC_SPLPAR
196 * Scan the dispatch trace log and count up the stolen time.
197 * Should be called with interrupts disabled.
199 static u64 scan_dispatch_log(u64 stop_tb)
201 u64 i = local_paca->dtl_ridx;
202 struct dtl_entry *dtl = local_paca->dtl_curr;
203 struct dtl_entry *dtl_end = local_paca->dispatch_log_end;
204 struct lppaca *vpa = local_paca->lppaca_ptr;
212 if (i == vpa->dtl_idx)
214 while (i < vpa->dtl_idx) {
216 dtl_consumer(dtl, i);
218 tb_delta = dtl->enqueue_to_dispatch_time +
219 dtl->ready_to_enqueue_time;
221 if (i + N_DISPATCH_LOG < vpa->dtl_idx) {
222 /* buffer has overflowed */
223 i = vpa->dtl_idx - N_DISPATCH_LOG;
224 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG);
233 dtl = local_paca->dispatch_log;
235 local_paca->dtl_ridx = i;
236 local_paca->dtl_curr = dtl;
241 * Accumulate stolen time by scanning the dispatch trace log.
242 * Called on entry from user mode.
244 void accumulate_stolen_time(void)
248 u8 save_soft_enabled = local_paca->soft_enabled;
250 /* We are called early in the exception entry, before
251 * soft/hard_enabled are sync'ed to the expected state
252 * for the exception. We are hard disabled but the PACA
253 * needs to reflect that so various debug stuff doesn't
256 local_paca->soft_enabled = 0;
258 sst = scan_dispatch_log(local_paca->starttime_user);
259 ust = scan_dispatch_log(local_paca->starttime);
260 local_paca->system_time -= sst;
261 local_paca->user_time -= ust;
262 local_paca->stolen_time += ust + sst;
264 local_paca->soft_enabled = save_soft_enabled;
267 static inline u64 calculate_stolen_time(u64 stop_tb)
271 if (get_paca()->dtl_ridx != get_paca()->lppaca_ptr->dtl_idx) {
272 stolen = scan_dispatch_log(stop_tb);
273 get_paca()->system_time -= stolen;
276 stolen += get_paca()->stolen_time;
277 get_paca()->stolen_time = 0;
281 #else /* CONFIG_PPC_SPLPAR */
282 static inline u64 calculate_stolen_time(u64 stop_tb)
287 #endif /* CONFIG_PPC_SPLPAR */
290 * Account time for a transition between system, hard irq
293 void account_system_vtime(struct task_struct *tsk)
295 u64 now, nowscaled, delta, deltascaled;
297 u64 stolen, udelta, sys_scaled, user_scaled;
299 local_irq_save(flags);
301 nowscaled = read_spurr(now);
302 get_paca()->system_time += now - get_paca()->starttime;
303 get_paca()->starttime = now;
304 deltascaled = nowscaled - get_paca()->startspurr;
305 get_paca()->startspurr = nowscaled;
307 stolen = calculate_stolen_time(now);
309 delta = get_paca()->system_time;
310 get_paca()->system_time = 0;
311 udelta = get_paca()->user_time - get_paca()->utime_sspurr;
312 get_paca()->utime_sspurr = get_paca()->user_time;
315 * Because we don't read the SPURR on every kernel entry/exit,
316 * deltascaled includes both user and system SPURR ticks.
317 * Apportion these ticks to system SPURR ticks and user
318 * SPURR ticks in the same ratio as the system time (delta)
319 * and user time (udelta) values obtained from the timebase
320 * over the same interval. The system ticks get accounted here;
321 * the user ticks get saved up in paca->user_time_scaled to be
322 * used by account_process_tick.
325 user_scaled = udelta;
326 if (deltascaled != delta + udelta) {
328 sys_scaled = deltascaled * delta / (delta + udelta);
329 user_scaled = deltascaled - sys_scaled;
331 sys_scaled = deltascaled;
334 get_paca()->user_time_scaled += user_scaled;
336 if (in_interrupt() || idle_task(smp_processor_id()) != tsk) {
337 account_system_time(tsk, 0, delta, sys_scaled);
339 account_steal_time(stolen);
341 account_idle_time(delta + stolen);
343 local_irq_restore(flags);
345 EXPORT_SYMBOL_GPL(account_system_vtime);
348 * Transfer the user and system times accumulated in the paca
349 * by the exception entry and exit code to the generic process
350 * user and system time records.
351 * Must be called with interrupts disabled.
352 * Assumes that account_system_vtime() has been called recently
353 * (i.e. since the last entry from usermode) so that
354 * get_paca()->user_time_scaled is up to date.
356 void account_process_tick(struct task_struct *tsk, int user_tick)
358 cputime_t utime, utimescaled;
360 utime = get_paca()->user_time;
361 utimescaled = get_paca()->user_time_scaled;
362 get_paca()->user_time = 0;
363 get_paca()->user_time_scaled = 0;
364 get_paca()->utime_sspurr = 0;
365 account_user_time(tsk, utime, utimescaled);
368 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
369 #define calc_cputime_factors()
372 void __delay(unsigned long loops)
380 /* the RTCL register wraps at 1000000000 */
381 diff = get_rtcl() - start;
384 } while (diff < loops);
387 while (get_tbl() - start < loops)
392 EXPORT_SYMBOL(__delay);
394 void udelay(unsigned long usecs)
396 __delay(tb_ticks_per_usec * usecs);
398 EXPORT_SYMBOL(udelay);
401 unsigned long profile_pc(struct pt_regs *regs)
403 unsigned long pc = instruction_pointer(regs);
405 if (in_lock_functions(pc))
410 EXPORT_SYMBOL(profile_pc);
413 #ifdef CONFIG_IRQ_WORK
416 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable...
419 static inline unsigned long test_irq_work_pending(void)
423 asm volatile("lbz %0,%1(13)"
425 : "i" (offsetof(struct paca_struct, irq_work_pending)));
429 static inline void set_irq_work_pending_flag(void)
431 asm volatile("stb %0,%1(13)" : :
433 "i" (offsetof(struct paca_struct, irq_work_pending)));
436 static inline void clear_irq_work_pending(void)
438 asm volatile("stb %0,%1(13)" : :
440 "i" (offsetof(struct paca_struct, irq_work_pending)));
445 DEFINE_PER_CPU(u8, irq_work_pending);
447 #define set_irq_work_pending_flag() __get_cpu_var(irq_work_pending) = 1
448 #define test_irq_work_pending() __get_cpu_var(irq_work_pending)
449 #define clear_irq_work_pending() __get_cpu_var(irq_work_pending) = 0
451 #endif /* 32 vs 64 bit */
453 void arch_irq_work_raise(void)
456 set_irq_work_pending_flag();
461 #else /* CONFIG_IRQ_WORK */
463 #define test_irq_work_pending() 0
464 #define clear_irq_work_pending()
466 #endif /* CONFIG_IRQ_WORK */
469 * timer_interrupt - gets called when the decrementer overflows,
470 * with interrupts disabled.
472 void timer_interrupt(struct pt_regs * regs)
474 struct pt_regs *old_regs;
475 u64 *next_tb = &__get_cpu_var(decrementers_next_tb);
476 struct clock_event_device *evt = &__get_cpu_var(decrementers);
478 /* Ensure a positive value is written to the decrementer, or else
479 * some CPUs will continue to take decrementer exceptions.
481 set_dec(DECREMENTER_MAX);
483 /* Some implementations of hotplug will get timer interrupts while
484 * offline, just ignore these
486 if (!cpu_online(smp_processor_id()))
489 /* Conditionally hard-enable interrupts now that the DEC has been
490 * bumped to its maximum value
492 may_hard_irq_enable();
494 trace_timer_interrupt_entry(regs);
496 __get_cpu_var(irq_stat).timer_irqs++;
498 #if defined(CONFIG_PPC32) && defined(CONFIG_PMAC)
499 if (atomic_read(&ppc_n_lost_interrupts) != 0)
503 old_regs = set_irq_regs(regs);
506 if (test_irq_work_pending()) {
507 clear_irq_work_pending();
512 if (evt->event_handler)
513 evt->event_handler(evt);
516 /* collect purr register values often, for accurate calculations */
517 if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
518 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
519 cu->current_tb = mfspr(SPRN_PURR);
524 set_irq_regs(old_regs);
526 trace_timer_interrupt_exit(regs);
529 #ifdef CONFIG_SUSPEND
530 static void generic_suspend_disable_irqs(void)
532 /* Disable the decrementer, so that it doesn't interfere
536 set_dec(DECREMENTER_MAX);
538 set_dec(DECREMENTER_MAX);
541 static void generic_suspend_enable_irqs(void)
546 /* Overrides the weak version in kernel/power/main.c */
547 void arch_suspend_disable_irqs(void)
549 if (ppc_md.suspend_disable_irqs)
550 ppc_md.suspend_disable_irqs();
551 generic_suspend_disable_irqs();
554 /* Overrides the weak version in kernel/power/main.c */
555 void arch_suspend_enable_irqs(void)
557 generic_suspend_enable_irqs();
558 if (ppc_md.suspend_enable_irqs)
559 ppc_md.suspend_enable_irqs();
564 * Scheduler clock - returns current time in nanosec units.
566 * Note: mulhdu(a, b) (multiply high double unsigned) returns
567 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
568 * are 64-bit unsigned numbers.
570 unsigned long long sched_clock(void)
574 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
577 static int __init get_freq(char *name, int cells, unsigned long *val)
579 struct device_node *cpu;
580 const unsigned int *fp;
583 /* The cpu node should have timebase and clock frequency properties */
584 cpu = of_find_node_by_type(NULL, "cpu");
587 fp = of_get_property(cpu, name, NULL);
590 *val = of_read_ulong(fp, cells);
599 /* should become __cpuinit when secondary_cpu_time_init also is */
600 void start_cpu_decrementer(void)
602 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
603 /* Clear any pending timer interrupts */
604 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS);
606 /* Enable decrementer interrupt */
607 mtspr(SPRN_TCR, TCR_DIE);
608 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */
611 void __init generic_calibrate_decr(void)
613 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */
615 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) &&
616 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) {
618 printk(KERN_ERR "WARNING: Estimating decrementer frequency "
622 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */
624 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) &&
625 !get_freq("clock-frequency", 1, &ppc_proc_freq)) {
627 printk(KERN_ERR "WARNING: Estimating processor frequency "
632 int update_persistent_clock(struct timespec now)
636 if (!ppc_md.set_rtc_time)
639 to_tm(now.tv_sec + 1 + timezone_offset, &tm);
643 return ppc_md.set_rtc_time(&tm);
646 static void __read_persistent_clock(struct timespec *ts)
649 static int first = 1;
652 /* XXX this is a litle fragile but will work okay in the short term */
655 if (ppc_md.time_init)
656 timezone_offset = ppc_md.time_init();
658 /* get_boot_time() isn't guaranteed to be safe to call late */
659 if (ppc_md.get_boot_time) {
660 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset;
664 if (!ppc_md.get_rtc_time) {
668 ppc_md.get_rtc_time(&tm);
670 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
671 tm.tm_hour, tm.tm_min, tm.tm_sec);
674 void read_persistent_clock(struct timespec *ts)
676 __read_persistent_clock(ts);
678 /* Sanitize it in case real time clock is set below EPOCH */
679 if (ts->tv_sec < 0) {
686 /* clocksource code */
687 static cycle_t rtc_read(struct clocksource *cs)
689 return (cycle_t)get_rtc();
692 static cycle_t timebase_read(struct clocksource *cs)
694 return (cycle_t)get_tb();
697 void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
698 struct clocksource *clock, u32 mult)
700 u64 new_tb_to_xs, new_stamp_xsec;
703 if (clock != &clocksource_timebase)
706 /* Make userspace gettimeofday spin until we're done. */
707 ++vdso_data->tb_update_count;
710 /* 19342813113834067 ~= 2^(20+64) / 1e9 */
711 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift);
712 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC;
713 do_div(new_stamp_xsec, 1000000000);
714 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC;
716 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC);
717 /* this is tv_nsec / 1e9 as a 0.32 fraction */
718 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32;
721 * tb_update_count is used to allow the userspace gettimeofday code
722 * to assure itself that it sees a consistent view of the tb_to_xs and
723 * stamp_xsec variables. It reads the tb_update_count, then reads
724 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
725 * the two values of tb_update_count match and are even then the
726 * tb_to_xs and stamp_xsec values are consistent. If not, then it
727 * loops back and reads them again until this criteria is met.
728 * We expect the caller to have done the first increment of
729 * vdso_data->tb_update_count already.
731 vdso_data->tb_orig_stamp = clock->cycle_last;
732 vdso_data->stamp_xsec = new_stamp_xsec;
733 vdso_data->tb_to_xs = new_tb_to_xs;
734 vdso_data->wtom_clock_sec = wtm->tv_sec;
735 vdso_data->wtom_clock_nsec = wtm->tv_nsec;
736 vdso_data->stamp_xtime = *wall_time;
737 vdso_data->stamp_sec_fraction = frac_sec;
739 ++(vdso_data->tb_update_count);
742 void update_vsyscall_tz(void)
744 /* Make userspace gettimeofday spin until we're done. */
745 ++vdso_data->tb_update_count;
747 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
748 vdso_data->tz_dsttime = sys_tz.tz_dsttime;
750 ++vdso_data->tb_update_count;
753 static void __init clocksource_init(void)
755 struct clocksource *clock;
758 clock = &clocksource_rtc;
760 clock = &clocksource_timebase;
762 if (clocksource_register_hz(clock, tb_ticks_per_sec)) {
763 printk(KERN_ERR "clocksource: %s is already registered\n",
768 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n",
769 clock->name, clock->mult, clock->shift);
772 static int decrementer_set_next_event(unsigned long evt,
773 struct clock_event_device *dev)
775 __get_cpu_var(decrementers_next_tb) = get_tb_or_rtc() + evt;
780 static void decrementer_set_mode(enum clock_event_mode mode,
781 struct clock_event_device *dev)
783 if (mode != CLOCK_EVT_MODE_ONESHOT)
784 decrementer_set_next_event(DECREMENTER_MAX, dev);
787 static void register_decrementer_clockevent(int cpu)
789 struct clock_event_device *dec = &per_cpu(decrementers, cpu);
791 *dec = decrementer_clockevent;
792 dec->cpumask = cpumask_of(cpu);
794 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n",
795 dec->name, dec->mult, dec->shift, cpu);
797 clockevents_register_device(dec);
800 static void __init init_decrementer_clockevent(void)
802 int cpu = smp_processor_id();
804 clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4);
806 decrementer_clockevent.max_delta_ns =
807 clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent);
808 decrementer_clockevent.min_delta_ns =
809 clockevent_delta2ns(2, &decrementer_clockevent);
811 register_decrementer_clockevent(cpu);
814 void secondary_cpu_time_init(void)
816 /* Start the decrementer on CPUs that have manual control
819 start_cpu_decrementer();
821 /* FIME: Should make unrelatred change to move snapshot_timebase
823 register_decrementer_clockevent(smp_processor_id());
826 /* This function is only called on the boot processor */
827 void __init time_init(void)
829 struct div_result res;
834 /* 601 processor: dec counts down by 128 every 128ns */
835 ppc_tb_freq = 1000000000;
837 /* Normal PowerPC with timebase register */
838 ppc_md.calibrate_decr();
839 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n",
840 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
841 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n",
842 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
845 tb_ticks_per_jiffy = ppc_tb_freq / HZ;
846 tb_ticks_per_sec = ppc_tb_freq;
847 tb_ticks_per_usec = ppc_tb_freq / 1000000;
848 calc_cputime_factors();
849 setup_cputime_one_jiffy();
852 * Compute scale factor for sched_clock.
853 * The calibrate_decr() function has set tb_ticks_per_sec,
854 * which is the timebase frequency.
855 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
856 * the 128-bit result as a 64.64 fixed-point number.
857 * We then shift that number right until it is less than 1.0,
858 * giving us the scale factor and shift count to use in
861 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res);
862 scale = res.result_low;
863 for (shift = 0; res.result_high != 0; ++shift) {
864 scale = (scale >> 1) | (res.result_high << 63);
865 res.result_high >>= 1;
867 tb_to_ns_scale = scale;
868 tb_to_ns_shift = shift;
869 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
870 boot_tb = get_tb_or_rtc();
872 /* If platform provided a timezone (pmac), we correct the time */
873 if (timezone_offset) {
874 sys_tz.tz_minuteswest = -timezone_offset / 60;
875 sys_tz.tz_dsttime = 0;
878 vdso_data->tb_update_count = 0;
879 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
881 /* Start the decrementer on CPUs that have manual control
884 start_cpu_decrementer();
886 /* Register the clocksource */
889 init_decrementer_clockevent();
894 #define STARTOFTIME 1970
895 #define SECDAY 86400L
896 #define SECYR (SECDAY * 365)
897 #define leapyear(year) ((year) % 4 == 0 && \
898 ((year) % 100 != 0 || (year) % 400 == 0))
899 #define days_in_year(a) (leapyear(a) ? 366 : 365)
900 #define days_in_month(a) (month_days[(a) - 1])
902 static int month_days[12] = {
903 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
907 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
909 void GregorianDay(struct rtc_time * tm)
914 int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
916 lastYear = tm->tm_year - 1;
919 * Number of leap corrections to apply up to end of last year
921 leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400;
924 * This year is a leap year if it is divisible by 4 except when it is
925 * divisible by 100 unless it is divisible by 400
927 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
929 day = tm->tm_mon > 2 && leapyear(tm->tm_year);
931 day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] +
934 tm->tm_wday = day % 7;
937 void to_tm(int tim, struct rtc_time * tm)
940 register long hms, day;
945 /* Hours, minutes, seconds are easy */
946 tm->tm_hour = hms / 3600;
947 tm->tm_min = (hms % 3600) / 60;
948 tm->tm_sec = (hms % 3600) % 60;
950 /* Number of years in days */
951 for (i = STARTOFTIME; day >= days_in_year(i); i++)
952 day -= days_in_year(i);
955 /* Number of months in days left */
956 if (leapyear(tm->tm_year))
957 days_in_month(FEBRUARY) = 29;
958 for (i = 1; day >= days_in_month(i); i++)
959 day -= days_in_month(i);
960 days_in_month(FEBRUARY) = 28;
963 /* Days are what is left over (+1) from all that. */
964 tm->tm_mday = day + 1;
967 * Determine the day of week
973 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
976 void div128_by_32(u64 dividend_high, u64 dividend_low,
977 unsigned divisor, struct div_result *dr)
979 unsigned long a, b, c, d;
980 unsigned long w, x, y, z;
983 a = dividend_high >> 32;
984 b = dividend_high & 0xffffffff;
985 c = dividend_low >> 32;
986 d = dividend_low & 0xffffffff;
989 ra = ((u64)(a - (w * divisor)) << 32) + b;
991 rb = ((u64) do_div(ra, divisor) << 32) + c;
994 rc = ((u64) do_div(rb, divisor) << 32) + d;
1000 dr->result_high = ((u64)w << 32) + x;
1001 dr->result_low = ((u64)y << 32) + z;
1005 /* We don't need to calibrate delay, we use the CPU timebase for that */
1006 void calibrate_delay(void)
1008 /* Some generic code (such as spinlock debug) use loops_per_jiffy
1009 * as the number of __delay(1) in a jiffy, so make it so
1011 loops_per_jiffy = tb_ticks_per_jiffy;
1014 static int __init rtc_init(void)
1016 struct platform_device *pdev;
1018 if (!ppc_md.get_rtc_time)
1021 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0);
1023 return PTR_ERR(pdev);
1028 module_init(rtc_init);