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>
57 #include <asm/processor.h>
58 #include <asm/nvram.h>
59 #include <asm/cache.h>
60 #include <asm/machdep.h>
61 #include <asm/uaccess.h>
65 #include <asm/div64.h>
67 #include <asm/vdso_datapage.h>
68 #include <asm/firmware.h>
69 #ifdef CONFIG_PPC_ISERIES
70 #include <asm/iseries/it_lp_queue.h>
71 #include <asm/iseries/hv_call_xm.h>
74 /* powerpc clocksource/clockevent code */
76 #include <linux/clockchips.h>
77 #include <linux/clocksource.h>
79 static cycle_t
rtc_read(void);
80 static struct clocksource clocksource_rtc
= {
83 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
84 .mask
= CLOCKSOURCE_MASK(64),
86 .mult
= 0, /* To be filled in */
90 static cycle_t
timebase_read(void);
91 static struct clocksource clocksource_timebase
= {
94 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
95 .mask
= CLOCKSOURCE_MASK(64),
97 .mult
= 0, /* To be filled in */
98 .read
= timebase_read
,
101 #define DECREMENTER_MAX 0x7fffffff
103 static int decrementer_set_next_event(unsigned long evt
,
104 struct clock_event_device
*dev
);
105 static void decrementer_set_mode(enum clock_event_mode mode
,
106 struct clock_event_device
*dev
);
108 static struct clock_event_device decrementer_clockevent
= {
109 .name
= "decrementer",
112 .mult
= 0, /* To be filled in */
114 .set_next_event
= decrementer_set_next_event
,
115 .set_mode
= decrementer_set_mode
,
116 .features
= CLOCK_EVT_FEAT_ONESHOT
,
119 struct decrementer_clock
{
120 struct clock_event_device event
;
124 static DEFINE_PER_CPU(struct decrementer_clock
, decrementers
);
126 #ifdef CONFIG_PPC_ISERIES
127 static unsigned long __initdata iSeries_recal_titan
;
128 static signed long __initdata iSeries_recal_tb
;
130 /* Forward declaration is only needed for iSereis compiles */
131 void __init
clocksource_init(void);
134 #define XSEC_PER_SEC (1024*1024)
137 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
139 /* compute ((xsec << 12) * max) >> 32 */
140 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
143 unsigned long tb_ticks_per_jiffy
;
144 unsigned long tb_ticks_per_usec
= 100; /* sane default */
145 EXPORT_SYMBOL(tb_ticks_per_usec
);
146 unsigned long tb_ticks_per_sec
;
147 EXPORT_SYMBOL(tb_ticks_per_sec
); /* for cputime_t conversions */
151 #define TICKLEN_SCALE TICK_LENGTH_SHIFT
152 u64 last_tick_len
; /* units are ns / 2^TICKLEN_SCALE */
153 u64 ticklen_to_xs
; /* 0.64 fraction */
155 /* If last_tick_len corresponds to about 1/HZ seconds, then
156 last_tick_len << TICKLEN_SHIFT will be about 2^63. */
157 #define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ)
159 DEFINE_SPINLOCK(rtc_lock
);
160 EXPORT_SYMBOL_GPL(rtc_lock
);
162 static u64 tb_to_ns_scale __read_mostly
;
163 static unsigned tb_to_ns_shift __read_mostly
;
164 static unsigned long boot_tb __read_mostly
;
166 struct gettimeofday_struct do_gtod
;
168 extern struct timezone sys_tz
;
169 static long timezone_offset
;
171 unsigned long ppc_proc_freq
;
172 EXPORT_SYMBOL(ppc_proc_freq
);
173 unsigned long ppc_tb_freq
;
175 static u64 tb_last_jiffy __cacheline_aligned_in_smp
;
176 static DEFINE_PER_CPU(u64
, last_jiffy
);
178 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
180 * Factors for converting from cputime_t (timebase ticks) to
181 * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds).
182 * These are all stored as 0.64 fixed-point binary fractions.
184 u64 __cputime_jiffies_factor
;
185 EXPORT_SYMBOL(__cputime_jiffies_factor
);
186 u64 __cputime_msec_factor
;
187 EXPORT_SYMBOL(__cputime_msec_factor
);
188 u64 __cputime_sec_factor
;
189 EXPORT_SYMBOL(__cputime_sec_factor
);
190 u64 __cputime_clockt_factor
;
191 EXPORT_SYMBOL(__cputime_clockt_factor
);
193 static void calc_cputime_factors(void)
195 struct div_result res
;
197 div128_by_32(HZ
, 0, tb_ticks_per_sec
, &res
);
198 __cputime_jiffies_factor
= res
.result_low
;
199 div128_by_32(1000, 0, tb_ticks_per_sec
, &res
);
200 __cputime_msec_factor
= res
.result_low
;
201 div128_by_32(1, 0, tb_ticks_per_sec
, &res
);
202 __cputime_sec_factor
= res
.result_low
;
203 div128_by_32(USER_HZ
, 0, tb_ticks_per_sec
, &res
);
204 __cputime_clockt_factor
= res
.result_low
;
208 * Read the PURR on systems that have it, otherwise the timebase.
210 static u64
read_purr(void)
212 if (cpu_has_feature(CPU_FTR_PURR
))
213 return mfspr(SPRN_PURR
);
218 * Read the SPURR on systems that have it, otherwise the purr
220 static u64
read_spurr(u64 purr
)
222 if (cpu_has_feature(CPU_FTR_SPURR
))
223 return mfspr(SPRN_SPURR
);
228 * Account time for a transition between system, hard irq
231 void account_system_vtime(struct task_struct
*tsk
)
233 u64 now
, nowscaled
, delta
, deltascaled
;
236 local_irq_save(flags
);
238 delta
= now
- get_paca()->startpurr
;
239 get_paca()->startpurr
= now
;
240 nowscaled
= read_spurr(now
);
241 deltascaled
= nowscaled
- get_paca()->startspurr
;
242 get_paca()->startspurr
= nowscaled
;
243 if (!in_interrupt()) {
244 /* deltascaled includes both user and system time.
245 * Hence scale it based on the purr ratio to estimate
247 if (get_paca()->user_time
)
248 deltascaled
= deltascaled
* get_paca()->system_time
/
249 (get_paca()->system_time
+ get_paca()->user_time
);
250 delta
+= get_paca()->system_time
;
251 get_paca()->system_time
= 0;
253 account_system_time(tsk
, 0, delta
);
254 get_paca()->purrdelta
= delta
;
255 account_system_time_scaled(tsk
, deltascaled
);
256 get_paca()->spurrdelta
= deltascaled
;
257 local_irq_restore(flags
);
261 * Transfer the user and system times accumulated in the paca
262 * by the exception entry and exit code to the generic process
263 * user and system time records.
264 * Must be called with interrupts disabled.
266 void account_process_tick(struct task_struct
*tsk
, int user_tick
)
268 cputime_t utime
, utimescaled
;
270 utime
= get_paca()->user_time
;
271 get_paca()->user_time
= 0;
272 account_user_time(tsk
, utime
);
274 /* Estimate the scaled utime by scaling the real utime based
275 * on the last spurr to purr ratio */
276 utimescaled
= utime
* get_paca()->spurrdelta
/ get_paca()->purrdelta
;
277 get_paca()->spurrdelta
= get_paca()->purrdelta
= 0;
278 account_user_time_scaled(tsk
, utimescaled
);
282 * Stuff for accounting stolen time.
284 struct cpu_purr_data
{
285 int initialized
; /* thread is running */
286 u64 tb
; /* last TB value read */
287 u64 purr
; /* last PURR value read */
288 u64 spurr
; /* last SPURR value read */
292 * Each entry in the cpu_purr_data array is manipulated only by its
293 * "owner" cpu -- usually in the timer interrupt but also occasionally
294 * in process context for cpu online. As long as cpus do not touch
295 * each others' cpu_purr_data, disabling local interrupts is
296 * sufficient to serialize accesses.
298 static DEFINE_PER_CPU(struct cpu_purr_data
, cpu_purr_data
);
300 static void snapshot_tb_and_purr(void *data
)
303 struct cpu_purr_data
*p
= &__get_cpu_var(cpu_purr_data
);
305 local_irq_save(flags
);
306 p
->tb
= get_tb_or_rtc();
307 p
->purr
= mfspr(SPRN_PURR
);
310 local_irq_restore(flags
);
314 * Called during boot when all cpus have come up.
316 void snapshot_timebases(void)
318 if (!cpu_has_feature(CPU_FTR_PURR
))
320 on_each_cpu(snapshot_tb_and_purr
, NULL
, 0, 1);
324 * Must be called with interrupts disabled.
326 void calculate_steal_time(void)
330 struct cpu_purr_data
*pme
;
332 pme
= &__get_cpu_var(cpu_purr_data
);
333 if (!pme
->initialized
)
334 return; /* !CPU_FTR_PURR or early in early boot */
336 purr
= mfspr(SPRN_PURR
);
337 stolen
= (tb
- pme
->tb
) - (purr
- pme
->purr
);
339 account_steal_time(current
, stolen
);
344 #ifdef CONFIG_PPC_SPLPAR
346 * Must be called before the cpu is added to the online map when
347 * a cpu is being brought up at runtime.
349 static void snapshot_purr(void)
351 struct cpu_purr_data
*pme
;
354 if (!cpu_has_feature(CPU_FTR_PURR
))
356 local_irq_save(flags
);
357 pme
= &__get_cpu_var(cpu_purr_data
);
359 pme
->purr
= mfspr(SPRN_PURR
);
360 pme
->initialized
= 1;
361 local_irq_restore(flags
);
364 #endif /* CONFIG_PPC_SPLPAR */
366 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
367 #define calc_cputime_factors()
368 #define calculate_steal_time() do { } while (0)
371 #if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR))
372 #define snapshot_purr() do { } while (0)
376 * Called when a cpu comes up after the system has finished booting,
377 * i.e. as a result of a hotplug cpu action.
379 void snapshot_timebase(void)
381 __get_cpu_var(last_jiffy
) = get_tb_or_rtc();
385 void __delay(unsigned long loops
)
393 /* the RTCL register wraps at 1000000000 */
394 diff
= get_rtcl() - start
;
397 } while (diff
< loops
);
400 while (get_tbl() - start
< loops
)
405 EXPORT_SYMBOL(__delay
);
407 void udelay(unsigned long usecs
)
409 __delay(tb_ticks_per_usec
* usecs
);
411 EXPORT_SYMBOL(udelay
);
415 * There are two copies of tb_to_xs and stamp_xsec so that no
416 * lock is needed to access and use these values in
417 * do_gettimeofday. We alternate the copies and as long as a
418 * reasonable time elapses between changes, there will never
419 * be inconsistent values. ntpd has a minimum of one minute
422 static inline void update_gtod(u64 new_tb_stamp
, u64 new_stamp_xsec
,
426 struct gettimeofday_vars
*temp_varp
;
428 temp_idx
= (do_gtod
.var_idx
== 0);
429 temp_varp
= &do_gtod
.vars
[temp_idx
];
431 temp_varp
->tb_to_xs
= new_tb_to_xs
;
432 temp_varp
->tb_orig_stamp
= new_tb_stamp
;
433 temp_varp
->stamp_xsec
= new_stamp_xsec
;
435 do_gtod
.varp
= temp_varp
;
436 do_gtod
.var_idx
= temp_idx
;
439 * tb_update_count is used to allow the userspace gettimeofday code
440 * to assure itself that it sees a consistent view of the tb_to_xs and
441 * stamp_xsec variables. It reads the tb_update_count, then reads
442 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
443 * the two values of tb_update_count match and are even then the
444 * tb_to_xs and stamp_xsec values are consistent. If not, then it
445 * loops back and reads them again until this criteria is met.
446 * We expect the caller to have done the first increment of
447 * vdso_data->tb_update_count already.
449 vdso_data
->tb_orig_stamp
= new_tb_stamp
;
450 vdso_data
->stamp_xsec
= new_stamp_xsec
;
451 vdso_data
->tb_to_xs
= new_tb_to_xs
;
452 vdso_data
->wtom_clock_sec
= wall_to_monotonic
.tv_sec
;
453 vdso_data
->wtom_clock_nsec
= wall_to_monotonic
.tv_nsec
;
455 ++(vdso_data
->tb_update_count
);
459 unsigned long profile_pc(struct pt_regs
*regs
)
461 unsigned long pc
= instruction_pointer(regs
);
463 if (in_lock_functions(pc
))
468 EXPORT_SYMBOL(profile_pc
);
471 #ifdef CONFIG_PPC_ISERIES
474 * This function recalibrates the timebase based on the 49-bit time-of-day
475 * value in the Titan chip. The Titan is much more accurate than the value
476 * returned by the service processor for the timebase frequency.
479 static int __init
iSeries_tb_recal(void)
481 struct div_result divres
;
482 unsigned long titan
, tb
;
484 /* Make sure we only run on iSeries */
485 if (!firmware_has_feature(FW_FEATURE_ISERIES
))
489 titan
= HvCallXm_loadTod();
490 if ( iSeries_recal_titan
) {
491 unsigned long tb_ticks
= tb
- iSeries_recal_tb
;
492 unsigned long titan_usec
= (titan
- iSeries_recal_titan
) >> 12;
493 unsigned long new_tb_ticks_per_sec
= (tb_ticks
* USEC_PER_SEC
)/titan_usec
;
494 unsigned long new_tb_ticks_per_jiffy
= (new_tb_ticks_per_sec
+(HZ
/2))/HZ
;
495 long tick_diff
= new_tb_ticks_per_jiffy
- tb_ticks_per_jiffy
;
497 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */
498 new_tb_ticks_per_sec
= new_tb_ticks_per_jiffy
* HZ
;
500 if ( tick_diff
< 0 ) {
501 tick_diff
= -tick_diff
;
505 if ( tick_diff
< tb_ticks_per_jiffy
/25 ) {
506 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n",
507 new_tb_ticks_per_jiffy
, sign
, tick_diff
);
508 tb_ticks_per_jiffy
= new_tb_ticks_per_jiffy
;
509 tb_ticks_per_sec
= new_tb_ticks_per_sec
;
510 calc_cputime_factors();
511 div128_by_32( XSEC_PER_SEC
, 0, tb_ticks_per_sec
, &divres
);
512 do_gtod
.tb_ticks_per_sec
= tb_ticks_per_sec
;
513 tb_to_xs
= divres
.result_low
;
514 do_gtod
.varp
->tb_to_xs
= tb_to_xs
;
515 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
516 vdso_data
->tb_to_xs
= tb_to_xs
;
519 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n"
520 " new tb_ticks_per_jiffy = %lu\n"
521 " old tb_ticks_per_jiffy = %lu\n",
522 new_tb_ticks_per_jiffy
, tb_ticks_per_jiffy
);
526 iSeries_recal_titan
= titan
;
527 iSeries_recal_tb
= tb
;
529 /* Called here as now we know accurate values for the timebase */
533 late_initcall(iSeries_tb_recal
);
535 /* Called from platform early init */
536 void __init
iSeries_time_init_early(void)
538 iSeries_recal_tb
= get_tb();
539 iSeries_recal_titan
= HvCallXm_loadTod();
541 #endif /* CONFIG_PPC_ISERIES */
544 * For iSeries shared processors, we have to let the hypervisor
545 * set the hardware decrementer. We set a virtual decrementer
546 * in the lppaca and call the hypervisor if the virtual
547 * decrementer is less than the current value in the hardware
548 * decrementer. (almost always the new decrementer value will
549 * be greater than the current hardware decementer so the hypervisor
550 * call will not be needed)
554 * timer_interrupt - gets called when the decrementer overflows,
555 * with interrupts disabled.
557 void timer_interrupt(struct pt_regs
* regs
)
559 struct pt_regs
*old_regs
;
560 struct decrementer_clock
*decrementer
= &__get_cpu_var(decrementers
);
561 struct clock_event_device
*evt
= &decrementer
->event
;
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
);
569 if (atomic_read(&ppc_n_lost_interrupts
) != 0)
573 now
= get_tb_or_rtc();
574 if (now
< decrementer
->next_tb
) {
575 /* not time for this event yet */
576 now
= decrementer
->next_tb
- now
;
577 if (now
<= DECREMENTER_MAX
)
581 old_regs
= set_irq_regs(regs
);
584 calculate_steal_time();
586 #ifdef CONFIG_PPC_ISERIES
587 if (firmware_has_feature(FW_FEATURE_ISERIES
))
588 get_lppaca()->int_dword
.fields
.decr_int
= 0;
591 if (evt
->event_handler
)
592 evt
->event_handler(evt
);
594 #ifdef CONFIG_PPC_ISERIES
595 if (firmware_has_feature(FW_FEATURE_ISERIES
) && hvlpevent_is_pending())
596 process_hvlpevents();
600 /* collect purr register values often, for accurate calculations */
601 if (firmware_has_feature(FW_FEATURE_SPLPAR
)) {
602 struct cpu_usage
*cu
= &__get_cpu_var(cpu_usage_array
);
603 cu
->current_tb
= mfspr(SPRN_PURR
);
608 set_irq_regs(old_regs
);
611 void wakeup_decrementer(void)
616 * The timebase gets saved on sleep and restored on wakeup,
617 * so all we need to do is to reset the decrementer.
619 ticks
= tb_ticks_since(__get_cpu_var(last_jiffy
));
620 if (ticks
< tb_ticks_per_jiffy
)
621 ticks
= tb_ticks_per_jiffy
- ticks
;
628 void __init
smp_space_timers(unsigned int max_cpus
)
631 u64 previous_tb
= per_cpu(last_jiffy
, boot_cpuid
);
633 /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */
634 previous_tb
-= tb_ticks_per_jiffy
;
636 for_each_possible_cpu(i
) {
639 per_cpu(last_jiffy
, i
) = previous_tb
;
645 * Scheduler clock - returns current time in nanosec units.
647 * Note: mulhdu(a, b) (multiply high double unsigned) returns
648 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
649 * are 64-bit unsigned numbers.
651 unsigned long long sched_clock(void)
655 return mulhdu(get_tb() - boot_tb
, tb_to_ns_scale
) << tb_to_ns_shift
;
658 static int __init
get_freq(char *name
, int cells
, unsigned long *val
)
660 struct device_node
*cpu
;
661 const unsigned int *fp
;
664 /* The cpu node should have timebase and clock frequency properties */
665 cpu
= of_find_node_by_type(NULL
, "cpu");
668 fp
= of_get_property(cpu
, name
, NULL
);
671 *val
= of_read_ulong(fp
, cells
);
680 void __init
generic_calibrate_decr(void)
682 ppc_tb_freq
= DEFAULT_TB_FREQ
; /* hardcoded default */
684 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq
) &&
685 !get_freq("timebase-frequency", 1, &ppc_tb_freq
)) {
687 printk(KERN_ERR
"WARNING: Estimating decrementer frequency "
691 ppc_proc_freq
= DEFAULT_PROC_FREQ
; /* hardcoded default */
693 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq
) &&
694 !get_freq("clock-frequency", 1, &ppc_proc_freq
)) {
696 printk(KERN_ERR
"WARNING: Estimating processor frequency "
700 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
701 /* Set the time base to zero */
705 /* Clear any pending timer interrupts */
706 mtspr(SPRN_TSR
, TSR_ENW
| TSR_WIS
| TSR_DIS
| TSR_FIS
);
708 /* Enable decrementer interrupt */
709 mtspr(SPRN_TCR
, TCR_DIE
);
713 int update_persistent_clock(struct timespec now
)
717 if (!ppc_md
.set_rtc_time
)
720 to_tm(now
.tv_sec
+ 1 + timezone_offset
, &tm
);
724 return ppc_md
.set_rtc_time(&tm
);
727 unsigned long read_persistent_clock(void)
730 static int first
= 1;
732 /* XXX this is a litle fragile but will work okay in the short term */
735 if (ppc_md
.time_init
)
736 timezone_offset
= ppc_md
.time_init();
738 /* get_boot_time() isn't guaranteed to be safe to call late */
739 if (ppc_md
.get_boot_time
)
740 return ppc_md
.get_boot_time() -timezone_offset
;
742 if (!ppc_md
.get_rtc_time
)
744 ppc_md
.get_rtc_time(&tm
);
745 return mktime(tm
.tm_year
+1900, tm
.tm_mon
+1, tm
.tm_mday
,
746 tm
.tm_hour
, tm
.tm_min
, tm
.tm_sec
);
749 /* clocksource code */
750 static cycle_t
rtc_read(void)
752 return (cycle_t
)get_rtc();
755 static cycle_t
timebase_read(void)
757 return (cycle_t
)get_tb();
760 void update_vsyscall(struct timespec
*wall_time
, struct clocksource
*clock
)
764 if (clock
!= &clocksource_timebase
)
767 /* Make userspace gettimeofday spin until we're done. */
768 ++vdso_data
->tb_update_count
;
771 /* XXX this assumes clock->shift == 22 */
772 /* 4611686018 ~= 2^(20+64-22) / 1e9 */
773 t2x
= (u64
) clock
->mult
* 4611686018ULL;
774 stamp_xsec
= (u64
) xtime
.tv_nsec
* XSEC_PER_SEC
;
775 do_div(stamp_xsec
, 1000000000);
776 stamp_xsec
+= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
777 update_gtod(clock
->cycle_last
, stamp_xsec
, t2x
);
780 void update_vsyscall_tz(void)
782 /* Make userspace gettimeofday spin until we're done. */
783 ++vdso_data
->tb_update_count
;
785 vdso_data
->tz_minuteswest
= sys_tz
.tz_minuteswest
;
786 vdso_data
->tz_dsttime
= sys_tz
.tz_dsttime
;
788 ++vdso_data
->tb_update_count
;
791 void __init
clocksource_init(void)
793 struct clocksource
*clock
;
796 clock
= &clocksource_rtc
;
798 clock
= &clocksource_timebase
;
800 clock
->mult
= clocksource_hz2mult(tb_ticks_per_sec
, clock
->shift
);
802 if (clocksource_register(clock
)) {
803 printk(KERN_ERR
"clocksource: %s is already registered\n",
808 printk(KERN_INFO
"clocksource: %s mult[%x] shift[%d] registered\n",
809 clock
->name
, clock
->mult
, clock
->shift
);
812 static int decrementer_set_next_event(unsigned long evt
,
813 struct clock_event_device
*dev
)
815 __get_cpu_var(decrementers
).next_tb
= get_tb_or_rtc() + evt
;
820 static void decrementer_set_mode(enum clock_event_mode mode
,
821 struct clock_event_device
*dev
)
823 if (mode
!= CLOCK_EVT_MODE_ONESHOT
)
824 decrementer_set_next_event(DECREMENTER_MAX
, dev
);
827 static void register_decrementer_clockevent(int cpu
)
829 struct clock_event_device
*dec
= &per_cpu(decrementers
, cpu
).event
;
831 *dec
= decrementer_clockevent
;
832 dec
->cpumask
= cpumask_of_cpu(cpu
);
834 printk(KERN_DEBUG
"clockevent: %s mult[%lx] shift[%d] cpu[%d]\n",
835 dec
->name
, dec
->mult
, dec
->shift
, cpu
);
837 clockevents_register_device(dec
);
840 static void __init
init_decrementer_clockevent(void)
842 int cpu
= smp_processor_id();
844 decrementer_clockevent
.mult
= div_sc(ppc_tb_freq
, NSEC_PER_SEC
,
845 decrementer_clockevent
.shift
);
846 decrementer_clockevent
.max_delta_ns
=
847 clockevent_delta2ns(DECREMENTER_MAX
, &decrementer_clockevent
);
848 decrementer_clockevent
.min_delta_ns
=
849 clockevent_delta2ns(2, &decrementer_clockevent
);
851 register_decrementer_clockevent(cpu
);
854 void secondary_cpu_time_init(void)
856 /* FIME: Should make unrelatred change to move snapshot_timebase
858 register_decrementer_clockevent(smp_processor_id());
861 /* This function is only called on the boot processor */
862 void __init
time_init(void)
865 struct div_result res
;
870 /* 601 processor: dec counts down by 128 every 128ns */
871 ppc_tb_freq
= 1000000000;
872 tb_last_jiffy
= get_rtcl();
874 /* Normal PowerPC with timebase register */
875 ppc_md
.calibrate_decr();
876 printk(KERN_DEBUG
"time_init: decrementer frequency = %lu.%.6lu MHz\n",
877 ppc_tb_freq
/ 1000000, ppc_tb_freq
% 1000000);
878 printk(KERN_DEBUG
"time_init: processor frequency = %lu.%.6lu MHz\n",
879 ppc_proc_freq
/ 1000000, ppc_proc_freq
% 1000000);
880 tb_last_jiffy
= get_tb();
883 tb_ticks_per_jiffy
= ppc_tb_freq
/ HZ
;
884 tb_ticks_per_sec
= ppc_tb_freq
;
885 tb_ticks_per_usec
= ppc_tb_freq
/ 1000000;
886 tb_to_us
= mulhwu_scale_factor(ppc_tb_freq
, 1000000);
887 calc_cputime_factors();
890 * Calculate the length of each tick in ns. It will not be
891 * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ.
892 * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq,
895 x
= (u64
) NSEC_PER_SEC
* tb_ticks_per_jiffy
+ ppc_tb_freq
- 1;
896 do_div(x
, ppc_tb_freq
);
898 last_tick_len
= x
<< TICKLEN_SCALE
;
901 * Compute ticklen_to_xs, which is a factor which gets multiplied
902 * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value.
904 * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9)
905 * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT
906 * which turns out to be N = 51 - SHIFT_HZ.
907 * This gives the result as a 0.64 fixed-point fraction.
908 * That value is reduced by an offset amounting to 1 xsec per
909 * 2^31 timebase ticks to avoid problems with time going backwards
910 * by 1 xsec when we do timer_recalc_offset due to losing the
911 * fractional xsec. That offset is equal to ppc_tb_freq/2^51
912 * since there are 2^20 xsec in a second.
914 div128_by_32((1ULL << 51) - ppc_tb_freq
, 0,
915 tb_ticks_per_jiffy
<< SHIFT_HZ
, &res
);
916 div128_by_32(res
.result_high
, res
.result_low
, NSEC_PER_SEC
, &res
);
917 ticklen_to_xs
= res
.result_low
;
919 /* Compute tb_to_xs from tick_nsec */
920 tb_to_xs
= mulhdu(last_tick_len
<< TICKLEN_SHIFT
, ticklen_to_xs
);
923 * Compute scale factor for sched_clock.
924 * The calibrate_decr() function has set tb_ticks_per_sec,
925 * which is the timebase frequency.
926 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
927 * the 128-bit result as a 64.64 fixed-point number.
928 * We then shift that number right until it is less than 1.0,
929 * giving us the scale factor and shift count to use in
932 div128_by_32(1000000000, 0, tb_ticks_per_sec
, &res
);
933 scale
= res
.result_low
;
934 for (shift
= 0; res
.result_high
!= 0; ++shift
) {
935 scale
= (scale
>> 1) | (res
.result_high
<< 63);
936 res
.result_high
>>= 1;
938 tb_to_ns_scale
= scale
;
939 tb_to_ns_shift
= shift
;
940 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
941 boot_tb
= get_tb_or_rtc();
943 write_seqlock_irqsave(&xtime_lock
, flags
);
945 /* If platform provided a timezone (pmac), we correct the time */
946 if (timezone_offset
) {
947 sys_tz
.tz_minuteswest
= -timezone_offset
/ 60;
948 sys_tz
.tz_dsttime
= 0;
951 do_gtod
.varp
= &do_gtod
.vars
[0];
953 do_gtod
.varp
->tb_orig_stamp
= tb_last_jiffy
;
954 __get_cpu_var(last_jiffy
) = tb_last_jiffy
;
955 do_gtod
.varp
->stamp_xsec
= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
956 do_gtod
.tb_ticks_per_sec
= tb_ticks_per_sec
;
957 do_gtod
.varp
->tb_to_xs
= tb_to_xs
;
958 do_gtod
.tb_to_us
= tb_to_us
;
960 vdso_data
->tb_orig_stamp
= tb_last_jiffy
;
961 vdso_data
->tb_update_count
= 0;
962 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
963 vdso_data
->stamp_xsec
= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
964 vdso_data
->tb_to_xs
= tb_to_xs
;
968 write_sequnlock_irqrestore(&xtime_lock
, flags
);
970 /* Register the clocksource, if we're not running on iSeries */
971 if (!firmware_has_feature(FW_FEATURE_ISERIES
))
974 init_decrementer_clockevent();
979 #define STARTOFTIME 1970
980 #define SECDAY 86400L
981 #define SECYR (SECDAY * 365)
982 #define leapyear(year) ((year) % 4 == 0 && \
983 ((year) % 100 != 0 || (year) % 400 == 0))
984 #define days_in_year(a) (leapyear(a) ? 366 : 365)
985 #define days_in_month(a) (month_days[(a) - 1])
987 static int month_days
[12] = {
988 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
992 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
994 void GregorianDay(struct rtc_time
* tm
)
999 int MonthOffset
[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
1001 lastYear
= tm
->tm_year
- 1;
1004 * Number of leap corrections to apply up to end of last year
1006 leapsToDate
= lastYear
/ 4 - lastYear
/ 100 + lastYear
/ 400;
1009 * This year is a leap year if it is divisible by 4 except when it is
1010 * divisible by 100 unless it is divisible by 400
1012 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
1014 day
= tm
->tm_mon
> 2 && leapyear(tm
->tm_year
);
1016 day
+= lastYear
*365 + leapsToDate
+ MonthOffset
[tm
->tm_mon
-1] +
1019 tm
->tm_wday
= day
% 7;
1022 void to_tm(int tim
, struct rtc_time
* tm
)
1025 register long hms
, day
;
1030 /* Hours, minutes, seconds are easy */
1031 tm
->tm_hour
= hms
/ 3600;
1032 tm
->tm_min
= (hms
% 3600) / 60;
1033 tm
->tm_sec
= (hms
% 3600) % 60;
1035 /* Number of years in days */
1036 for (i
= STARTOFTIME
; day
>= days_in_year(i
); i
++)
1037 day
-= days_in_year(i
);
1040 /* Number of months in days left */
1041 if (leapyear(tm
->tm_year
))
1042 days_in_month(FEBRUARY
) = 29;
1043 for (i
= 1; day
>= days_in_month(i
); i
++)
1044 day
-= days_in_month(i
);
1045 days_in_month(FEBRUARY
) = 28;
1048 /* Days are what is left over (+1) from all that. */
1049 tm
->tm_mday
= day
+ 1;
1052 * Determine the day of week
1057 /* Auxiliary function to compute scaling factors */
1058 /* Actually the choice of a timebase running at 1/4 the of the bus
1059 * frequency giving resolution of a few tens of nanoseconds is quite nice.
1060 * It makes this computation very precise (27-28 bits typically) which
1061 * is optimistic considering the stability of most processor clock
1062 * oscillators and the precision with which the timebase frequency
1063 * is measured but does not harm.
1065 unsigned mulhwu_scale_factor(unsigned inscale
, unsigned outscale
)
1067 unsigned mlt
=0, tmp
, err
;
1068 /* No concern for performance, it's done once: use a stupid
1069 * but safe and compact method to find the multiplier.
1072 for (tmp
= 1U<<31; tmp
!= 0; tmp
>>= 1) {
1073 if (mulhwu(inscale
, mlt
|tmp
) < outscale
)
1077 /* We might still be off by 1 for the best approximation.
1078 * A side effect of this is that if outscale is too large
1079 * the returned value will be zero.
1080 * Many corner cases have been checked and seem to work,
1081 * some might have been forgotten in the test however.
1084 err
= inscale
* (mlt
+1);
1085 if (err
<= inscale
/2)
1091 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1094 void div128_by_32(u64 dividend_high
, u64 dividend_low
,
1095 unsigned divisor
, struct div_result
*dr
)
1097 unsigned long a
, b
, c
, d
;
1098 unsigned long w
, x
, y
, z
;
1101 a
= dividend_high
>> 32;
1102 b
= dividend_high
& 0xffffffff;
1103 c
= dividend_low
>> 32;
1104 d
= dividend_low
& 0xffffffff;
1107 ra
= ((u64
)(a
- (w
* divisor
)) << 32) + b
;
1109 rb
= ((u64
) do_div(ra
, divisor
) << 32) + c
;
1112 rc
= ((u64
) do_div(rb
, divisor
) << 32) + d
;
1115 do_div(rc
, divisor
);
1118 dr
->result_high
= ((u64
)w
<< 32) + x
;
1119 dr
->result_low
= ((u64
)y
<< 32) + z
;