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. (for iSeries, we calibrate the timebase
21 * against the Titan chip's clock.)
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
29 * This program is free software; you can redistribute it and/or
30 * modify it under the terms of the GNU General Public License
31 * as published by the Free Software Foundation; either version
32 * 2 of the License, or (at your option) any later version.
35 #include <linux/errno.h>
36 #include <linux/module.h>
37 #include <linux/sched.h>
38 #include <linux/kernel.h>
39 #include <linux/param.h>
40 #include <linux/string.h>
42 #include <linux/interrupt.h>
43 #include <linux/timex.h>
44 #include <linux/kernel_stat.h>
45 #include <linux/time.h>
46 #include <linux/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/perf_event.h>
57 #include <asm/trace.h>
60 #include <asm/processor.h>
61 #include <asm/nvram.h>
62 #include <asm/cache.h>
63 #include <asm/machdep.h>
64 #include <asm/uaccess.h>
68 #include <asm/div64.h>
70 #include <asm/vdso_datapage.h>
71 #include <asm/firmware.h>
72 #include <asm/cputime.h>
73 #ifdef CONFIG_PPC_ISERIES
74 #include <asm/iseries/it_lp_queue.h>
75 #include <asm/iseries/hv_call_xm.h>
78 /* powerpc clocksource/clockevent code */
80 #include <linux/clockchips.h>
81 #include <linux/clocksource.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),
90 .mult
= 0, /* To be filled in */
94 static cycle_t
timebase_read(struct clocksource
*);
95 static struct clocksource clocksource_timebase
= {
98 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
99 .mask
= CLOCKSOURCE_MASK(64),
101 .mult
= 0, /* To be filled in */
102 .read
= timebase_read
,
105 #define DECREMENTER_MAX 0x7fffffff
107 static int decrementer_set_next_event(unsigned long evt
,
108 struct clock_event_device
*dev
);
109 static void decrementer_set_mode(enum clock_event_mode mode
,
110 struct clock_event_device
*dev
);
112 static struct clock_event_device decrementer_clockevent
= {
113 .name
= "decrementer",
115 .shift
= 0, /* To be filled in */
116 .mult
= 0, /* To be filled in */
118 .set_next_event
= decrementer_set_next_event
,
119 .set_mode
= decrementer_set_mode
,
120 .features
= CLOCK_EVT_FEAT_ONESHOT
,
123 struct decrementer_clock
{
124 struct clock_event_device event
;
128 static DEFINE_PER_CPU(struct decrementer_clock
, decrementers
);
130 #ifdef CONFIG_PPC_ISERIES
131 static unsigned long __initdata iSeries_recal_titan
;
132 static signed long __initdata iSeries_recal_tb
;
134 /* Forward declaration is only needed for iSereis compiles */
135 static void __init
clocksource_init(void);
138 #define XSEC_PER_SEC (1024*1024)
141 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
143 /* compute ((xsec << 12) * max) >> 32 */
144 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
147 unsigned long tb_ticks_per_jiffy
;
148 unsigned long tb_ticks_per_usec
= 100; /* sane default */
149 EXPORT_SYMBOL(tb_ticks_per_usec
);
150 unsigned long tb_ticks_per_sec
;
151 EXPORT_SYMBOL(tb_ticks_per_sec
); /* for cputime_t conversions */
153 DEFINE_SPINLOCK(rtc_lock
);
154 EXPORT_SYMBOL_GPL(rtc_lock
);
156 static u64 tb_to_ns_scale __read_mostly
;
157 static unsigned tb_to_ns_shift __read_mostly
;
158 static unsigned long boot_tb __read_mostly
;
160 extern struct timezone sys_tz
;
161 static long timezone_offset
;
163 unsigned long ppc_proc_freq
;
164 EXPORT_SYMBOL(ppc_proc_freq
);
165 unsigned long ppc_tb_freq
;
167 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
169 * Factors for converting from cputime_t (timebase ticks) to
170 * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds).
171 * These are all stored as 0.64 fixed-point binary fractions.
173 u64 __cputime_jiffies_factor
;
174 EXPORT_SYMBOL(__cputime_jiffies_factor
);
175 u64 __cputime_msec_factor
;
176 EXPORT_SYMBOL(__cputime_msec_factor
);
177 u64 __cputime_sec_factor
;
178 EXPORT_SYMBOL(__cputime_sec_factor
);
179 u64 __cputime_clockt_factor
;
180 EXPORT_SYMBOL(__cputime_clockt_factor
);
181 DEFINE_PER_CPU(unsigned long, cputime_last_delta
);
182 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta
);
184 cputime_t cputime_one_jiffy
;
186 static void calc_cputime_factors(void)
188 struct div_result res
;
190 div128_by_32(HZ
, 0, tb_ticks_per_sec
, &res
);
191 __cputime_jiffies_factor
= res
.result_low
;
192 div128_by_32(1000, 0, tb_ticks_per_sec
, &res
);
193 __cputime_msec_factor
= res
.result_low
;
194 div128_by_32(1, 0, tb_ticks_per_sec
, &res
);
195 __cputime_sec_factor
= res
.result_low
;
196 div128_by_32(USER_HZ
, 0, tb_ticks_per_sec
, &res
);
197 __cputime_clockt_factor
= res
.result_low
;
201 * Read the SPURR on systems that have it, otherwise the PURR,
202 * or if that doesn't exist return the timebase value passed in.
204 static u64
read_spurr(u64 tb
)
206 if (cpu_has_feature(CPU_FTR_SPURR
))
207 return mfspr(SPRN_SPURR
);
208 if (cpu_has_feature(CPU_FTR_PURR
))
209 return mfspr(SPRN_PURR
);
213 #ifdef CONFIG_PPC_SPLPAR
216 * Scan the dispatch trace log and count up the stolen time.
217 * Should be called with interrupts disabled.
219 static u64
scan_dispatch_log(u64 stop_tb
)
221 unsigned long i
= local_paca
->dtl_ridx
;
222 struct dtl_entry
*dtl
= local_paca
->dtl_curr
;
223 struct dtl_entry
*dtl_end
= local_paca
->dispatch_log_end
;
224 struct lppaca
*vpa
= local_paca
->lppaca_ptr
;
229 if (i
== vpa
->dtl_idx
)
231 while (i
< vpa
->dtl_idx
) {
233 tb_delta
= dtl
->enqueue_to_dispatch_time
+
234 dtl
->ready_to_enqueue_time
;
236 if (i
+ N_DISPATCH_LOG
< vpa
->dtl_idx
) {
237 /* buffer has overflowed */
238 i
= vpa
->dtl_idx
- N_DISPATCH_LOG
;
239 dtl
= local_paca
->dispatch_log
+ (i
% N_DISPATCH_LOG
);
248 dtl
= local_paca
->dispatch_log
;
250 local_paca
->dtl_ridx
= i
;
251 local_paca
->dtl_curr
= dtl
;
256 * Accumulate stolen time by scanning the dispatch trace log.
257 * Called on entry from user mode.
259 void accumulate_stolen_time(void)
263 sst
= scan_dispatch_log(get_paca()->starttime_user
);
264 ust
= scan_dispatch_log(get_paca()->starttime
);
265 get_paca()->system_time
-= sst
;
266 get_paca()->user_time
-= ust
;
267 get_paca()->stolen_time
+= ust
+ sst
;
270 static inline u64
calculate_stolen_time(u64 stop_tb
)
274 if (get_paca()->dtl_ridx
!= get_paca()->lppaca_ptr
->dtl_idx
) {
275 stolen
= scan_dispatch_log(stop_tb
);
276 get_paca()->system_time
-= stolen
;
279 stolen
+= get_paca()->stolen_time
;
280 get_paca()->stolen_time
= 0;
284 #else /* CONFIG_PPC_SPLPAR */
285 static inline u64
calculate_stolen_time(u64 stop_tb
)
290 #endif /* CONFIG_PPC_SPLPAR */
293 * Account time for a transition between system, hard irq
296 void account_system_vtime(struct task_struct
*tsk
)
298 u64 now
, nowscaled
, delta
, deltascaled
;
300 u64 stolen
, udelta
, sys_scaled
, user_scaled
;
302 local_irq_save(flags
);
304 nowscaled
= read_spurr(now
);
305 get_paca()->system_time
+= now
- get_paca()->starttime
;
306 get_paca()->starttime
= now
;
307 deltascaled
= nowscaled
- get_paca()->startspurr
;
308 get_paca()->startspurr
= nowscaled
;
310 stolen
= calculate_stolen_time(now
);
312 delta
= get_paca()->system_time
;
313 get_paca()->system_time
= 0;
314 udelta
= get_paca()->user_time
- get_paca()->utime_sspurr
;
315 get_paca()->utime_sspurr
= get_paca()->user_time
;
318 * Because we don't read the SPURR on every kernel entry/exit,
319 * deltascaled includes both user and system SPURR ticks.
320 * Apportion these ticks to system SPURR ticks and user
321 * SPURR ticks in the same ratio as the system time (delta)
322 * and user time (udelta) values obtained from the timebase
323 * over the same interval. The system ticks get accounted here;
324 * the user ticks get saved up in paca->user_time_scaled to be
325 * used by account_process_tick.
328 user_scaled
= udelta
;
329 if (deltascaled
!= delta
+ udelta
) {
331 sys_scaled
= deltascaled
* delta
/ (delta
+ udelta
);
332 user_scaled
= deltascaled
- sys_scaled
;
334 sys_scaled
= deltascaled
;
337 get_paca()->user_time_scaled
+= user_scaled
;
339 if (in_irq() || idle_task(smp_processor_id()) != tsk
) {
340 account_system_time(tsk
, 0, delta
, sys_scaled
);
342 account_steal_time(stolen
);
344 account_idle_time(delta
+ stolen
);
346 local_irq_restore(flags
);
348 EXPORT_SYMBOL_GPL(account_system_vtime
);
351 * Transfer the user and system times accumulated in the paca
352 * by the exception entry and exit code to the generic process
353 * user and system time records.
354 * Must be called with interrupts disabled.
355 * Assumes that account_system_vtime() has been called recently
356 * (i.e. since the last entry from usermode) so that
357 * get_paca()->user_time_scaled is up to date.
359 void account_process_tick(struct task_struct
*tsk
, int user_tick
)
361 cputime_t utime
, utimescaled
;
363 utime
= get_paca()->user_time
;
364 utimescaled
= get_paca()->user_time_scaled
;
365 get_paca()->user_time
= 0;
366 get_paca()->user_time_scaled
= 0;
367 get_paca()->utime_sspurr
= 0;
368 account_user_time(tsk
, utime
, utimescaled
);
371 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
372 #define calc_cputime_factors()
375 void __delay(unsigned long loops
)
383 /* the RTCL register wraps at 1000000000 */
384 diff
= get_rtcl() - start
;
387 } while (diff
< loops
);
390 while (get_tbl() - start
< loops
)
395 EXPORT_SYMBOL(__delay
);
397 void udelay(unsigned long usecs
)
399 __delay(tb_ticks_per_usec
* usecs
);
401 EXPORT_SYMBOL(udelay
);
404 unsigned long profile_pc(struct pt_regs
*regs
)
406 unsigned long pc
= instruction_pointer(regs
);
408 if (in_lock_functions(pc
))
413 EXPORT_SYMBOL(profile_pc
);
416 #ifdef CONFIG_PPC_ISERIES
419 * This function recalibrates the timebase based on the 49-bit time-of-day
420 * value in the Titan chip. The Titan is much more accurate than the value
421 * returned by the service processor for the timebase frequency.
424 static int __init
iSeries_tb_recal(void)
426 unsigned long titan
, tb
;
428 /* Make sure we only run on iSeries */
429 if (!firmware_has_feature(FW_FEATURE_ISERIES
))
433 titan
= HvCallXm_loadTod();
434 if ( iSeries_recal_titan
) {
435 unsigned long tb_ticks
= tb
- iSeries_recal_tb
;
436 unsigned long titan_usec
= (titan
- iSeries_recal_titan
) >> 12;
437 unsigned long new_tb_ticks_per_sec
= (tb_ticks
* USEC_PER_SEC
)/titan_usec
;
438 unsigned long new_tb_ticks_per_jiffy
=
439 DIV_ROUND_CLOSEST(new_tb_ticks_per_sec
, HZ
);
440 long tick_diff
= new_tb_ticks_per_jiffy
- tb_ticks_per_jiffy
;
442 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */
443 new_tb_ticks_per_sec
= new_tb_ticks_per_jiffy
* HZ
;
445 if ( tick_diff
< 0 ) {
446 tick_diff
= -tick_diff
;
450 if ( tick_diff
< tb_ticks_per_jiffy
/25 ) {
451 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n",
452 new_tb_ticks_per_jiffy
, sign
, tick_diff
);
453 tb_ticks_per_jiffy
= new_tb_ticks_per_jiffy
;
454 tb_ticks_per_sec
= new_tb_ticks_per_sec
;
455 calc_cputime_factors();
456 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
457 setup_cputime_one_jiffy();
460 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n"
461 " new tb_ticks_per_jiffy = %lu\n"
462 " old tb_ticks_per_jiffy = %lu\n",
463 new_tb_ticks_per_jiffy
, tb_ticks_per_jiffy
);
467 iSeries_recal_titan
= titan
;
468 iSeries_recal_tb
= tb
;
470 /* Called here as now we know accurate values for the timebase */
474 late_initcall(iSeries_tb_recal
);
476 /* Called from platform early init */
477 void __init
iSeries_time_init_early(void)
479 iSeries_recal_tb
= get_tb();
480 iSeries_recal_titan
= HvCallXm_loadTod();
482 #endif /* CONFIG_PPC_ISERIES */
484 #ifdef CONFIG_PERF_EVENTS
487 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable...
490 static inline unsigned long test_perf_event_pending(void)
494 asm volatile("lbz %0,%1(13)"
496 : "i" (offsetof(struct paca_struct
, perf_event_pending
)));
500 static inline void set_perf_event_pending_flag(void)
502 asm volatile("stb %0,%1(13)" : :
504 "i" (offsetof(struct paca_struct
, perf_event_pending
)));
507 static inline void clear_perf_event_pending(void)
509 asm volatile("stb %0,%1(13)" : :
511 "i" (offsetof(struct paca_struct
, perf_event_pending
)));
516 DEFINE_PER_CPU(u8
, perf_event_pending
);
518 #define set_perf_event_pending_flag() __get_cpu_var(perf_event_pending) = 1
519 #define test_perf_event_pending() __get_cpu_var(perf_event_pending)
520 #define clear_perf_event_pending() __get_cpu_var(perf_event_pending) = 0
522 #endif /* 32 vs 64 bit */
524 void set_perf_event_pending(void)
527 set_perf_event_pending_flag();
532 #else /* CONFIG_PERF_EVENTS */
534 #define test_perf_event_pending() 0
535 #define clear_perf_event_pending()
537 #endif /* CONFIG_PERF_EVENTS */
540 * For iSeries shared processors, we have to let the hypervisor
541 * set the hardware decrementer. We set a virtual decrementer
542 * in the lppaca and call the hypervisor if the virtual
543 * decrementer is less than the current value in the hardware
544 * decrementer. (almost always the new decrementer value will
545 * be greater than the current hardware decementer so the hypervisor
546 * call will not be needed)
550 * timer_interrupt - gets called when the decrementer overflows,
551 * with interrupts disabled.
553 void timer_interrupt(struct pt_regs
* regs
)
555 struct pt_regs
*old_regs
;
556 struct decrementer_clock
*decrementer
= &__get_cpu_var(decrementers
);
557 struct clock_event_device
*evt
= &decrementer
->event
;
560 trace_timer_interrupt_entry(regs
);
562 __get_cpu_var(irq_stat
).timer_irqs
++;
564 /* Ensure a positive value is written to the decrementer, or else
565 * some CPUs will continuue to take decrementer exceptions */
566 set_dec(DECREMENTER_MAX
);
568 #if defined(CONFIG_PPC32) && defined(CONFIG_PMAC)
569 if (atomic_read(&ppc_n_lost_interrupts
) != 0)
573 old_regs
= set_irq_regs(regs
);
576 if (test_perf_event_pending()) {
577 clear_perf_event_pending();
578 perf_event_do_pending();
581 #ifdef CONFIG_PPC_ISERIES
582 if (firmware_has_feature(FW_FEATURE_ISERIES
))
583 get_lppaca()->int_dword
.fields
.decr_int
= 0;
586 now
= get_tb_or_rtc();
587 if (now
>= decrementer
->next_tb
) {
588 decrementer
->next_tb
= ~(u64
)0;
589 if (evt
->event_handler
)
590 evt
->event_handler(evt
);
592 now
= decrementer
->next_tb
- now
;
593 if (now
<= DECREMENTER_MAX
)
597 #ifdef CONFIG_PPC_ISERIES
598 if (firmware_has_feature(FW_FEATURE_ISERIES
) && hvlpevent_is_pending())
599 process_hvlpevents();
603 /* collect purr register values often, for accurate calculations */
604 if (firmware_has_feature(FW_FEATURE_SPLPAR
)) {
605 struct cpu_usage
*cu
= &__get_cpu_var(cpu_usage_array
);
606 cu
->current_tb
= mfspr(SPRN_PURR
);
611 set_irq_regs(old_regs
);
613 trace_timer_interrupt_exit(regs
);
616 #ifdef CONFIG_SUSPEND
617 static void generic_suspend_disable_irqs(void)
619 /* Disable the decrementer, so that it doesn't interfere
628 static void generic_suspend_enable_irqs(void)
633 /* Overrides the weak version in kernel/power/main.c */
634 void arch_suspend_disable_irqs(void)
636 if (ppc_md
.suspend_disable_irqs
)
637 ppc_md
.suspend_disable_irqs();
638 generic_suspend_disable_irqs();
641 /* Overrides the weak version in kernel/power/main.c */
642 void arch_suspend_enable_irqs(void)
644 generic_suspend_enable_irqs();
645 if (ppc_md
.suspend_enable_irqs
)
646 ppc_md
.suspend_enable_irqs();
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
;
664 static int __init
get_freq(char *name
, int cells
, unsigned long *val
)
666 struct device_node
*cpu
;
667 const unsigned int *fp
;
670 /* The cpu node should have timebase and clock frequency properties */
671 cpu
= of_find_node_by_type(NULL
, "cpu");
674 fp
= of_get_property(cpu
, name
, NULL
);
677 *val
= of_read_ulong(fp
, cells
);
686 /* should become __cpuinit when secondary_cpu_time_init also is */
687 void start_cpu_decrementer(void)
689 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
690 /* Clear any pending timer interrupts */
691 mtspr(SPRN_TSR
, TSR_ENW
| TSR_WIS
| TSR_DIS
| TSR_FIS
);
693 /* Enable decrementer interrupt */
694 mtspr(SPRN_TCR
, TCR_DIE
);
695 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */
698 void __init
generic_calibrate_decr(void)
700 ppc_tb_freq
= DEFAULT_TB_FREQ
; /* hardcoded default */
702 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq
) &&
703 !get_freq("timebase-frequency", 1, &ppc_tb_freq
)) {
705 printk(KERN_ERR
"WARNING: Estimating decrementer frequency "
709 ppc_proc_freq
= DEFAULT_PROC_FREQ
; /* hardcoded default */
711 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq
) &&
712 !get_freq("clock-frequency", 1, &ppc_proc_freq
)) {
714 printk(KERN_ERR
"WARNING: Estimating processor frequency "
719 int update_persistent_clock(struct timespec now
)
723 if (!ppc_md
.set_rtc_time
)
726 to_tm(now
.tv_sec
+ 1 + timezone_offset
, &tm
);
730 return ppc_md
.set_rtc_time(&tm
);
733 static void __read_persistent_clock(struct timespec
*ts
)
736 static int first
= 1;
739 /* XXX this is a litle fragile but will work okay in the short term */
742 if (ppc_md
.time_init
)
743 timezone_offset
= ppc_md
.time_init();
745 /* get_boot_time() isn't guaranteed to be safe to call late */
746 if (ppc_md
.get_boot_time
) {
747 ts
->tv_sec
= ppc_md
.get_boot_time() - timezone_offset
;
751 if (!ppc_md
.get_rtc_time
) {
755 ppc_md
.get_rtc_time(&tm
);
757 ts
->tv_sec
= mktime(tm
.tm_year
+1900, tm
.tm_mon
+1, tm
.tm_mday
,
758 tm
.tm_hour
, tm
.tm_min
, tm
.tm_sec
);
761 void read_persistent_clock(struct timespec
*ts
)
763 __read_persistent_clock(ts
);
765 /* Sanitize it in case real time clock is set below EPOCH */
766 if (ts
->tv_sec
< 0) {
773 /* clocksource code */
774 static cycle_t
rtc_read(struct clocksource
*cs
)
776 return (cycle_t
)get_rtc();
779 static cycle_t
timebase_read(struct clocksource
*cs
)
781 return (cycle_t
)get_tb();
784 void update_vsyscall(struct timespec
*wall_time
, struct timespec
*wtm
,
785 struct clocksource
*clock
, u32 mult
)
787 u64 new_tb_to_xs
, new_stamp_xsec
;
790 if (clock
!= &clocksource_timebase
)
793 /* Make userspace gettimeofday spin until we're done. */
794 ++vdso_data
->tb_update_count
;
797 /* XXX this assumes clock->shift == 22 */
798 /* 4611686018 ~= 2^(20+64-22) / 1e9 */
799 new_tb_to_xs
= (u64
) mult
* 4611686018ULL;
800 new_stamp_xsec
= (u64
) wall_time
->tv_nsec
* XSEC_PER_SEC
;
801 do_div(new_stamp_xsec
, 1000000000);
802 new_stamp_xsec
+= (u64
) wall_time
->tv_sec
* XSEC_PER_SEC
;
804 BUG_ON(wall_time
->tv_nsec
>= NSEC_PER_SEC
);
805 /* this is tv_nsec / 1e9 as a 0.32 fraction */
806 frac_sec
= ((u64
) wall_time
->tv_nsec
* 18446744073ULL) >> 32;
809 * tb_update_count is used to allow the userspace gettimeofday code
810 * to assure itself that it sees a consistent view of the tb_to_xs and
811 * stamp_xsec variables. It reads the tb_update_count, then reads
812 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
813 * the two values of tb_update_count match and are even then the
814 * tb_to_xs and stamp_xsec values are consistent. If not, then it
815 * loops back and reads them again until this criteria is met.
816 * We expect the caller to have done the first increment of
817 * vdso_data->tb_update_count already.
819 vdso_data
->tb_orig_stamp
= clock
->cycle_last
;
820 vdso_data
->stamp_xsec
= new_stamp_xsec
;
821 vdso_data
->tb_to_xs
= new_tb_to_xs
;
822 vdso_data
->wtom_clock_sec
= wtm
->tv_sec
;
823 vdso_data
->wtom_clock_nsec
= wtm
->tv_nsec
;
824 vdso_data
->stamp_xtime
= *wall_time
;
825 vdso_data
->stamp_sec_fraction
= frac_sec
;
827 ++(vdso_data
->tb_update_count
);
830 void update_vsyscall_tz(void)
832 /* Make userspace gettimeofday spin until we're done. */
833 ++vdso_data
->tb_update_count
;
835 vdso_data
->tz_minuteswest
= sys_tz
.tz_minuteswest
;
836 vdso_data
->tz_dsttime
= sys_tz
.tz_dsttime
;
838 ++vdso_data
->tb_update_count
;
841 static void __init
clocksource_init(void)
843 struct clocksource
*clock
;
846 clock
= &clocksource_rtc
;
848 clock
= &clocksource_timebase
;
850 clock
->mult
= clocksource_hz2mult(tb_ticks_per_sec
, clock
->shift
);
852 if (clocksource_register(clock
)) {
853 printk(KERN_ERR
"clocksource: %s is already registered\n",
858 printk(KERN_INFO
"clocksource: %s mult[%x] shift[%d] registered\n",
859 clock
->name
, clock
->mult
, clock
->shift
);
862 static int decrementer_set_next_event(unsigned long evt
,
863 struct clock_event_device
*dev
)
865 __get_cpu_var(decrementers
).next_tb
= get_tb_or_rtc() + evt
;
870 static void decrementer_set_mode(enum clock_event_mode mode
,
871 struct clock_event_device
*dev
)
873 if (mode
!= CLOCK_EVT_MODE_ONESHOT
)
874 decrementer_set_next_event(DECREMENTER_MAX
, dev
);
877 static inline uint64_t div_sc64(unsigned long ticks
, unsigned long nsec
,
880 uint64_t tmp
= ((uint64_t)ticks
) << shift
;
886 static void __init
setup_clockevent_multiplier(unsigned long hz
)
888 u64 mult
, shift
= 32;
891 mult
= div_sc64(hz
, NSEC_PER_SEC
, shift
);
892 if (mult
&& (mult
>> 32UL) == 0UL)
898 decrementer_clockevent
.shift
= shift
;
899 decrementer_clockevent
.mult
= mult
;
902 static void register_decrementer_clockevent(int cpu
)
904 struct clock_event_device
*dec
= &per_cpu(decrementers
, cpu
).event
;
906 *dec
= decrementer_clockevent
;
907 dec
->cpumask
= cpumask_of(cpu
);
909 printk_once(KERN_DEBUG
"clockevent: %s mult[%x] shift[%d] cpu[%d]\n",
910 dec
->name
, dec
->mult
, dec
->shift
, cpu
);
912 clockevents_register_device(dec
);
915 static void __init
init_decrementer_clockevent(void)
917 int cpu
= smp_processor_id();
919 setup_clockevent_multiplier(ppc_tb_freq
);
920 decrementer_clockevent
.max_delta_ns
=
921 clockevent_delta2ns(DECREMENTER_MAX
, &decrementer_clockevent
);
922 decrementer_clockevent
.min_delta_ns
=
923 clockevent_delta2ns(2, &decrementer_clockevent
);
925 register_decrementer_clockevent(cpu
);
928 void secondary_cpu_time_init(void)
930 /* Start the decrementer on CPUs that have manual control
933 start_cpu_decrementer();
935 /* FIME: Should make unrelatred change to move snapshot_timebase
937 register_decrementer_clockevent(smp_processor_id());
940 /* This function is only called on the boot processor */
941 void __init
time_init(void)
943 struct div_result res
;
948 /* 601 processor: dec counts down by 128 every 128ns */
949 ppc_tb_freq
= 1000000000;
951 /* Normal PowerPC with timebase register */
952 ppc_md
.calibrate_decr();
953 printk(KERN_DEBUG
"time_init: decrementer frequency = %lu.%.6lu MHz\n",
954 ppc_tb_freq
/ 1000000, ppc_tb_freq
% 1000000);
955 printk(KERN_DEBUG
"time_init: processor frequency = %lu.%.6lu MHz\n",
956 ppc_proc_freq
/ 1000000, ppc_proc_freq
% 1000000);
959 tb_ticks_per_jiffy
= ppc_tb_freq
/ HZ
;
960 tb_ticks_per_sec
= ppc_tb_freq
;
961 tb_ticks_per_usec
= ppc_tb_freq
/ 1000000;
962 calc_cputime_factors();
963 setup_cputime_one_jiffy();
966 * Compute scale factor for sched_clock.
967 * The calibrate_decr() function has set tb_ticks_per_sec,
968 * which is the timebase frequency.
969 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
970 * the 128-bit result as a 64.64 fixed-point number.
971 * We then shift that number right until it is less than 1.0,
972 * giving us the scale factor and shift count to use in
975 div128_by_32(1000000000, 0, tb_ticks_per_sec
, &res
);
976 scale
= res
.result_low
;
977 for (shift
= 0; res
.result_high
!= 0; ++shift
) {
978 scale
= (scale
>> 1) | (res
.result_high
<< 63);
979 res
.result_high
>>= 1;
981 tb_to_ns_scale
= scale
;
982 tb_to_ns_shift
= shift
;
983 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
984 boot_tb
= get_tb_or_rtc();
986 /* If platform provided a timezone (pmac), we correct the time */
987 if (timezone_offset
) {
988 sys_tz
.tz_minuteswest
= -timezone_offset
/ 60;
989 sys_tz
.tz_dsttime
= 0;
992 vdso_data
->tb_update_count
= 0;
993 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
995 /* Start the decrementer on CPUs that have manual control
998 start_cpu_decrementer();
1000 /* Register the clocksource, if we're not running on iSeries */
1001 if (!firmware_has_feature(FW_FEATURE_ISERIES
))
1004 init_decrementer_clockevent();
1009 #define STARTOFTIME 1970
1010 #define SECDAY 86400L
1011 #define SECYR (SECDAY * 365)
1012 #define leapyear(year) ((year) % 4 == 0 && \
1013 ((year) % 100 != 0 || (year) % 400 == 0))
1014 #define days_in_year(a) (leapyear(a) ? 366 : 365)
1015 #define days_in_month(a) (month_days[(a) - 1])
1017 static int month_days
[12] = {
1018 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
1022 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
1024 void GregorianDay(struct rtc_time
* tm
)
1029 int MonthOffset
[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
1031 lastYear
= tm
->tm_year
- 1;
1034 * Number of leap corrections to apply up to end of last year
1036 leapsToDate
= lastYear
/ 4 - lastYear
/ 100 + lastYear
/ 400;
1039 * This year is a leap year if it is divisible by 4 except when it is
1040 * divisible by 100 unless it is divisible by 400
1042 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
1044 day
= tm
->tm_mon
> 2 && leapyear(tm
->tm_year
);
1046 day
+= lastYear
*365 + leapsToDate
+ MonthOffset
[tm
->tm_mon
-1] +
1049 tm
->tm_wday
= day
% 7;
1052 void to_tm(int tim
, struct rtc_time
* tm
)
1055 register long hms
, day
;
1060 /* Hours, minutes, seconds are easy */
1061 tm
->tm_hour
= hms
/ 3600;
1062 tm
->tm_min
= (hms
% 3600) / 60;
1063 tm
->tm_sec
= (hms
% 3600) % 60;
1065 /* Number of years in days */
1066 for (i
= STARTOFTIME
; day
>= days_in_year(i
); i
++)
1067 day
-= days_in_year(i
);
1070 /* Number of months in days left */
1071 if (leapyear(tm
->tm_year
))
1072 days_in_month(FEBRUARY
) = 29;
1073 for (i
= 1; day
>= days_in_month(i
); i
++)
1074 day
-= days_in_month(i
);
1075 days_in_month(FEBRUARY
) = 28;
1078 /* Days are what is left over (+1) from all that. */
1079 tm
->tm_mday
= day
+ 1;
1082 * Determine the day of week
1088 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1091 void div128_by_32(u64 dividend_high
, u64 dividend_low
,
1092 unsigned divisor
, struct div_result
*dr
)
1094 unsigned long a
, b
, c
, d
;
1095 unsigned long w
, x
, y
, z
;
1098 a
= dividend_high
>> 32;
1099 b
= dividend_high
& 0xffffffff;
1100 c
= dividend_low
>> 32;
1101 d
= dividend_low
& 0xffffffff;
1104 ra
= ((u64
)(a
- (w
* divisor
)) << 32) + b
;
1106 rb
= ((u64
) do_div(ra
, divisor
) << 32) + c
;
1109 rc
= ((u64
) do_div(rb
, divisor
) << 32) + d
;
1112 do_div(rc
, divisor
);
1115 dr
->result_high
= ((u64
)w
<< 32) + x
;
1116 dr
->result_low
= ((u64
)y
<< 32) + z
;
1120 /* We don't need to calibrate delay, we use the CPU timebase for that */
1121 void calibrate_delay(void)
1123 /* Some generic code (such as spinlock debug) use loops_per_jiffy
1124 * as the number of __delay(1) in a jiffy, so make it so
1126 loops_per_jiffy
= tb_ticks_per_jiffy
;
1129 static int __init
rtc_init(void)
1131 struct platform_device
*pdev
;
1133 if (!ppc_md
.get_rtc_time
)
1136 pdev
= platform_device_register_simple("rtc-generic", -1, NULL
, 0);
1138 return PTR_ERR(pdev
);
1143 module_init(rtc_init
);