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 static DEFINE_PER_CPU(struct clock_event_device
, decrementers
);
120 static DEFINE_PER_CPU(u64
, decrementer_next_tb
);
122 #ifdef CONFIG_PPC_ISERIES
123 static unsigned long __initdata iSeries_recal_titan
;
124 static signed long __initdata iSeries_recal_tb
;
126 /* Forward declaration is only needed for iSereis compiles */
127 void __init
clocksource_init(void);
130 #define XSEC_PER_SEC (1024*1024)
133 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
135 /* compute ((xsec << 12) * max) >> 32 */
136 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
139 unsigned long tb_ticks_per_jiffy
;
140 unsigned long tb_ticks_per_usec
= 100; /* sane default */
141 EXPORT_SYMBOL(tb_ticks_per_usec
);
142 unsigned long tb_ticks_per_sec
;
143 EXPORT_SYMBOL(tb_ticks_per_sec
); /* for cputime_t conversions */
147 #define TICKLEN_SCALE TICK_LENGTH_SHIFT
148 u64 last_tick_len
; /* units are ns / 2^TICKLEN_SCALE */
149 u64 ticklen_to_xs
; /* 0.64 fraction */
151 /* If last_tick_len corresponds to about 1/HZ seconds, then
152 last_tick_len << TICKLEN_SHIFT will be about 2^63. */
153 #define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ)
155 DEFINE_SPINLOCK(rtc_lock
);
156 EXPORT_SYMBOL_GPL(rtc_lock
);
158 static u64 tb_to_ns_scale __read_mostly
;
159 static unsigned tb_to_ns_shift __read_mostly
;
160 static unsigned long boot_tb __read_mostly
;
162 struct gettimeofday_struct do_gtod
;
164 extern struct timezone sys_tz
;
165 static long timezone_offset
;
167 unsigned long ppc_proc_freq
;
168 EXPORT_SYMBOL(ppc_proc_freq
);
169 unsigned long ppc_tb_freq
;
171 static u64 tb_last_jiffy __cacheline_aligned_in_smp
;
172 static DEFINE_PER_CPU(u64
, last_jiffy
);
174 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
176 * Factors for converting from cputime_t (timebase ticks) to
177 * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds).
178 * These are all stored as 0.64 fixed-point binary fractions.
180 u64 __cputime_jiffies_factor
;
181 EXPORT_SYMBOL(__cputime_jiffies_factor
);
182 u64 __cputime_msec_factor
;
183 EXPORT_SYMBOL(__cputime_msec_factor
);
184 u64 __cputime_sec_factor
;
185 EXPORT_SYMBOL(__cputime_sec_factor
);
186 u64 __cputime_clockt_factor
;
187 EXPORT_SYMBOL(__cputime_clockt_factor
);
189 static void calc_cputime_factors(void)
191 struct div_result res
;
193 div128_by_32(HZ
, 0, tb_ticks_per_sec
, &res
);
194 __cputime_jiffies_factor
= res
.result_low
;
195 div128_by_32(1000, 0, tb_ticks_per_sec
, &res
);
196 __cputime_msec_factor
= res
.result_low
;
197 div128_by_32(1, 0, tb_ticks_per_sec
, &res
);
198 __cputime_sec_factor
= res
.result_low
;
199 div128_by_32(USER_HZ
, 0, tb_ticks_per_sec
, &res
);
200 __cputime_clockt_factor
= res
.result_low
;
204 * Read the PURR on systems that have it, otherwise the timebase.
206 static u64
read_purr(void)
208 if (cpu_has_feature(CPU_FTR_PURR
))
209 return mfspr(SPRN_PURR
);
214 * Read the SPURR on systems that have it, otherwise the purr
216 static u64
read_spurr(u64 purr
)
218 if (cpu_has_feature(CPU_FTR_SPURR
))
219 return mfspr(SPRN_SPURR
);
224 * Account time for a transition between system, hard irq
227 void account_system_vtime(struct task_struct
*tsk
)
229 u64 now
, nowscaled
, delta
, deltascaled
;
232 local_irq_save(flags
);
234 delta
= now
- get_paca()->startpurr
;
235 get_paca()->startpurr
= now
;
236 nowscaled
= read_spurr(now
);
237 deltascaled
= nowscaled
- get_paca()->startspurr
;
238 get_paca()->startspurr
= nowscaled
;
239 if (!in_interrupt()) {
240 /* deltascaled includes both user and system time.
241 * Hence scale it based on the purr ratio to estimate
243 if (get_paca()->user_time
)
244 deltascaled
= deltascaled
* get_paca()->system_time
/
245 (get_paca()->system_time
+ get_paca()->user_time
);
246 delta
+= get_paca()->system_time
;
247 get_paca()->system_time
= 0;
249 account_system_time(tsk
, 0, delta
);
250 get_paca()->purrdelta
= delta
;
251 account_system_time_scaled(tsk
, deltascaled
);
252 get_paca()->spurrdelta
= deltascaled
;
253 local_irq_restore(flags
);
257 * Transfer the user and system times accumulated in the paca
258 * by the exception entry and exit code to the generic process
259 * user and system time records.
260 * Must be called with interrupts disabled.
262 void account_process_tick(struct task_struct
*tsk
, int user_tick
)
264 cputime_t utime
, utimescaled
;
266 utime
= get_paca()->user_time
;
267 get_paca()->user_time
= 0;
268 account_user_time(tsk
, utime
);
270 /* Estimate the scaled utime by scaling the real utime based
271 * on the last spurr to purr ratio */
272 utimescaled
= utime
* get_paca()->spurrdelta
/ get_paca()->purrdelta
;
273 get_paca()->spurrdelta
= get_paca()->purrdelta
= 0;
274 account_user_time_scaled(tsk
, utimescaled
);
278 * Stuff for accounting stolen time.
280 struct cpu_purr_data
{
281 int initialized
; /* thread is running */
282 u64 tb
; /* last TB value read */
283 u64 purr
; /* last PURR value read */
284 u64 spurr
; /* last SPURR value read */
288 * Each entry in the cpu_purr_data array is manipulated only by its
289 * "owner" cpu -- usually in the timer interrupt but also occasionally
290 * in process context for cpu online. As long as cpus do not touch
291 * each others' cpu_purr_data, disabling local interrupts is
292 * sufficient to serialize accesses.
294 static DEFINE_PER_CPU(struct cpu_purr_data
, cpu_purr_data
);
296 static void snapshot_tb_and_purr(void *data
)
299 struct cpu_purr_data
*p
= &__get_cpu_var(cpu_purr_data
);
301 local_irq_save(flags
);
302 p
->tb
= get_tb_or_rtc();
303 p
->purr
= mfspr(SPRN_PURR
);
306 local_irq_restore(flags
);
310 * Called during boot when all cpus have come up.
312 void snapshot_timebases(void)
314 if (!cpu_has_feature(CPU_FTR_PURR
))
316 on_each_cpu(snapshot_tb_and_purr
, NULL
, 0, 1);
320 * Must be called with interrupts disabled.
322 void calculate_steal_time(void)
326 struct cpu_purr_data
*pme
;
328 if (!cpu_has_feature(CPU_FTR_PURR
))
330 pme
= &__get_cpu_var(cpu_purr_data
);
331 if (!pme
->initialized
)
332 return; /* this can happen in early boot */
334 purr
= mfspr(SPRN_PURR
);
335 stolen
= (tb
- pme
->tb
) - (purr
- pme
->purr
);
337 account_steal_time(current
, stolen
);
342 #ifdef CONFIG_PPC_SPLPAR
344 * Must be called before the cpu is added to the online map when
345 * a cpu is being brought up at runtime.
347 static void snapshot_purr(void)
349 struct cpu_purr_data
*pme
;
352 if (!cpu_has_feature(CPU_FTR_PURR
))
354 local_irq_save(flags
);
355 pme
= &__get_cpu_var(cpu_purr_data
);
357 pme
->purr
= mfspr(SPRN_PURR
);
358 pme
->initialized
= 1;
359 local_irq_restore(flags
);
362 #endif /* CONFIG_PPC_SPLPAR */
364 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
365 #define calc_cputime_factors()
366 #define calculate_steal_time() do { } while (0)
369 #if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR))
370 #define snapshot_purr() do { } while (0)
374 * Called when a cpu comes up after the system has finished booting,
375 * i.e. as a result of a hotplug cpu action.
377 void snapshot_timebase(void)
379 __get_cpu_var(last_jiffy
) = get_tb_or_rtc();
383 void __delay(unsigned long loops
)
391 /* the RTCL register wraps at 1000000000 */
392 diff
= get_rtcl() - start
;
395 } while (diff
< loops
);
398 while (get_tbl() - start
< loops
)
403 EXPORT_SYMBOL(__delay
);
405 void udelay(unsigned long usecs
)
407 __delay(tb_ticks_per_usec
* usecs
);
409 EXPORT_SYMBOL(udelay
);
413 * There are two copies of tb_to_xs and stamp_xsec so that no
414 * lock is needed to access and use these values in
415 * do_gettimeofday. We alternate the copies and as long as a
416 * reasonable time elapses between changes, there will never
417 * be inconsistent values. ntpd has a minimum of one minute
420 static inline void update_gtod(u64 new_tb_stamp
, u64 new_stamp_xsec
,
424 struct gettimeofday_vars
*temp_varp
;
426 temp_idx
= (do_gtod
.var_idx
== 0);
427 temp_varp
= &do_gtod
.vars
[temp_idx
];
429 temp_varp
->tb_to_xs
= new_tb_to_xs
;
430 temp_varp
->tb_orig_stamp
= new_tb_stamp
;
431 temp_varp
->stamp_xsec
= new_stamp_xsec
;
433 do_gtod
.varp
= temp_varp
;
434 do_gtod
.var_idx
= temp_idx
;
437 * tb_update_count is used to allow the userspace gettimeofday code
438 * to assure itself that it sees a consistent view of the tb_to_xs and
439 * stamp_xsec variables. It reads the tb_update_count, then reads
440 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
441 * the two values of tb_update_count match and are even then the
442 * tb_to_xs and stamp_xsec values are consistent. If not, then it
443 * loops back and reads them again until this criteria is met.
444 * We expect the caller to have done the first increment of
445 * vdso_data->tb_update_count already.
447 vdso_data
->tb_orig_stamp
= new_tb_stamp
;
448 vdso_data
->stamp_xsec
= new_stamp_xsec
;
449 vdso_data
->tb_to_xs
= new_tb_to_xs
;
450 vdso_data
->wtom_clock_sec
= wall_to_monotonic
.tv_sec
;
451 vdso_data
->wtom_clock_nsec
= wall_to_monotonic
.tv_nsec
;
453 ++(vdso_data
->tb_update_count
);
457 unsigned long profile_pc(struct pt_regs
*regs
)
459 unsigned long pc
= instruction_pointer(regs
);
461 if (in_lock_functions(pc
))
466 EXPORT_SYMBOL(profile_pc
);
469 #ifdef CONFIG_PPC_ISERIES
472 * This function recalibrates the timebase based on the 49-bit time-of-day
473 * value in the Titan chip. The Titan is much more accurate than the value
474 * returned by the service processor for the timebase frequency.
477 static int __init
iSeries_tb_recal(void)
479 struct div_result divres
;
480 unsigned long titan
, tb
;
482 /* Make sure we only run on iSeries */
483 if (!firmware_has_feature(FW_FEATURE_ISERIES
))
487 titan
= HvCallXm_loadTod();
488 if ( iSeries_recal_titan
) {
489 unsigned long tb_ticks
= tb
- iSeries_recal_tb
;
490 unsigned long titan_usec
= (titan
- iSeries_recal_titan
) >> 12;
491 unsigned long new_tb_ticks_per_sec
= (tb_ticks
* USEC_PER_SEC
)/titan_usec
;
492 unsigned long new_tb_ticks_per_jiffy
= (new_tb_ticks_per_sec
+(HZ
/2))/HZ
;
493 long tick_diff
= new_tb_ticks_per_jiffy
- tb_ticks_per_jiffy
;
495 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */
496 new_tb_ticks_per_sec
= new_tb_ticks_per_jiffy
* HZ
;
498 if ( tick_diff
< 0 ) {
499 tick_diff
= -tick_diff
;
503 if ( tick_diff
< tb_ticks_per_jiffy
/25 ) {
504 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n",
505 new_tb_ticks_per_jiffy
, sign
, tick_diff
);
506 tb_ticks_per_jiffy
= new_tb_ticks_per_jiffy
;
507 tb_ticks_per_sec
= new_tb_ticks_per_sec
;
508 calc_cputime_factors();
509 div128_by_32( XSEC_PER_SEC
, 0, tb_ticks_per_sec
, &divres
);
510 do_gtod
.tb_ticks_per_sec
= tb_ticks_per_sec
;
511 tb_to_xs
= divres
.result_low
;
512 do_gtod
.varp
->tb_to_xs
= tb_to_xs
;
513 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
514 vdso_data
->tb_to_xs
= tb_to_xs
;
517 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n"
518 " new tb_ticks_per_jiffy = %lu\n"
519 " old tb_ticks_per_jiffy = %lu\n",
520 new_tb_ticks_per_jiffy
, tb_ticks_per_jiffy
);
524 iSeries_recal_titan
= titan
;
525 iSeries_recal_tb
= tb
;
527 /* Called here as now we know accurate values for the timebase */
531 late_initcall(iSeries_tb_recal
);
533 /* Called from platform early init */
534 void __init
iSeries_time_init_early(void)
536 iSeries_recal_tb
= get_tb();
537 iSeries_recal_titan
= HvCallXm_loadTod();
539 #endif /* CONFIG_PPC_ISERIES */
542 * For iSeries shared processors, we have to let the hypervisor
543 * set the hardware decrementer. We set a virtual decrementer
544 * in the lppaca and call the hypervisor if the virtual
545 * decrementer is less than the current value in the hardware
546 * decrementer. (almost always the new decrementer value will
547 * be greater than the current hardware decementer so the hypervisor
548 * call will not be needed)
552 * timer_interrupt - gets called when the decrementer overflows,
553 * with interrupts disabled.
555 void timer_interrupt(struct pt_regs
* regs
)
557 struct pt_regs
*old_regs
;
558 int cpu
= smp_processor_id();
559 struct clock_event_device
*evt
= &per_cpu(decrementers
, cpu
);
562 /* Ensure a positive value is written to the decrementer, or else
563 * some CPUs will continuue to take decrementer exceptions */
564 set_dec(DECREMENTER_MAX
);
567 if (atomic_read(&ppc_n_lost_interrupts
) != 0)
571 now
= get_tb_or_rtc();
572 if (now
< per_cpu(decrementer_next_tb
, cpu
)) {
573 /* not time for this event yet */
574 now
= per_cpu(decrementer_next_tb
, cpu
) - now
;
575 if (now
<= DECREMENTER_MAX
)
579 old_regs
= set_irq_regs(regs
);
582 calculate_steal_time();
584 #ifdef CONFIG_PPC_ISERIES
585 if (firmware_has_feature(FW_FEATURE_ISERIES
))
586 get_lppaca()->int_dword
.fields
.decr_int
= 0;
589 if (evt
->event_handler
)
590 evt
->event_handler(evt
);
592 #ifdef CONFIG_PPC_ISERIES
593 if (firmware_has_feature(FW_FEATURE_ISERIES
) && hvlpevent_is_pending())
594 process_hvlpevents();
598 /* collect purr register values often, for accurate calculations */
599 if (firmware_has_feature(FW_FEATURE_SPLPAR
)) {
600 struct cpu_usage
*cu
= &__get_cpu_var(cpu_usage_array
);
601 cu
->current_tb
= mfspr(SPRN_PURR
);
606 set_irq_regs(old_regs
);
609 void wakeup_decrementer(void)
614 * The timebase gets saved on sleep and restored on wakeup,
615 * so all we need to do is to reset the decrementer.
617 ticks
= tb_ticks_since(__get_cpu_var(last_jiffy
));
618 if (ticks
< tb_ticks_per_jiffy
)
619 ticks
= tb_ticks_per_jiffy
- ticks
;
626 void __init
smp_space_timers(unsigned int max_cpus
)
629 u64 previous_tb
= per_cpu(last_jiffy
, boot_cpuid
);
631 /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */
632 previous_tb
-= tb_ticks_per_jiffy
;
634 for_each_possible_cpu(i
) {
637 per_cpu(last_jiffy
, i
) = previous_tb
;
643 * Scheduler clock - returns current time in nanosec units.
645 * Note: mulhdu(a, b) (multiply high double unsigned) returns
646 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
647 * are 64-bit unsigned numbers.
649 unsigned long long sched_clock(void)
653 return mulhdu(get_tb() - boot_tb
, tb_to_ns_scale
) << tb_to_ns_shift
;
656 static int __init
get_freq(char *name
, int cells
, unsigned long *val
)
658 struct device_node
*cpu
;
659 const unsigned int *fp
;
662 /* The cpu node should have timebase and clock frequency properties */
663 cpu
= of_find_node_by_type(NULL
, "cpu");
666 fp
= of_get_property(cpu
, name
, NULL
);
669 *val
= of_read_ulong(fp
, cells
);
678 void __init
generic_calibrate_decr(void)
680 ppc_tb_freq
= DEFAULT_TB_FREQ
; /* hardcoded default */
682 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq
) &&
683 !get_freq("timebase-frequency", 1, &ppc_tb_freq
)) {
685 printk(KERN_ERR
"WARNING: Estimating decrementer frequency "
689 ppc_proc_freq
= DEFAULT_PROC_FREQ
; /* hardcoded default */
691 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq
) &&
692 !get_freq("clock-frequency", 1, &ppc_proc_freq
)) {
694 printk(KERN_ERR
"WARNING: Estimating processor frequency "
698 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
699 /* Set the time base to zero */
703 /* Clear any pending timer interrupts */
704 mtspr(SPRN_TSR
, TSR_ENW
| TSR_WIS
| TSR_DIS
| TSR_FIS
);
706 /* Enable decrementer interrupt */
707 mtspr(SPRN_TCR
, TCR_DIE
);
711 int update_persistent_clock(struct timespec now
)
715 if (!ppc_md
.set_rtc_time
)
718 to_tm(now
.tv_sec
+ 1 + timezone_offset
, &tm
);
722 return ppc_md
.set_rtc_time(&tm
);
725 unsigned long read_persistent_clock(void)
728 static int first
= 1;
730 /* XXX this is a litle fragile but will work okay in the short term */
733 if (ppc_md
.time_init
)
734 timezone_offset
= ppc_md
.time_init();
736 /* get_boot_time() isn't guaranteed to be safe to call late */
737 if (ppc_md
.get_boot_time
)
738 return ppc_md
.get_boot_time() -timezone_offset
;
740 if (!ppc_md
.get_rtc_time
)
742 ppc_md
.get_rtc_time(&tm
);
743 return mktime(tm
.tm_year
+1900, tm
.tm_mon
+1, tm
.tm_mday
,
744 tm
.tm_hour
, tm
.tm_min
, tm
.tm_sec
);
747 /* clocksource code */
748 static cycle_t
rtc_read(void)
750 return (cycle_t
)get_rtc();
753 static cycle_t
timebase_read(void)
755 return (cycle_t
)get_tb();
758 void update_vsyscall(struct timespec
*wall_time
, struct clocksource
*clock
)
762 if (clock
!= &clocksource_timebase
)
765 /* Make userspace gettimeofday spin until we're done. */
766 ++vdso_data
->tb_update_count
;
769 /* XXX this assumes clock->shift == 22 */
770 /* 4611686018 ~= 2^(20+64-22) / 1e9 */
771 t2x
= (u64
) clock
->mult
* 4611686018ULL;
772 stamp_xsec
= (u64
) xtime
.tv_nsec
* XSEC_PER_SEC
;
773 do_div(stamp_xsec
, 1000000000);
774 stamp_xsec
+= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
775 update_gtod(clock
->cycle_last
, stamp_xsec
, t2x
);
778 void update_vsyscall_tz(void)
780 /* Make userspace gettimeofday spin until we're done. */
781 ++vdso_data
->tb_update_count
;
783 vdso_data
->tz_minuteswest
= sys_tz
.tz_minuteswest
;
784 vdso_data
->tz_dsttime
= sys_tz
.tz_dsttime
;
786 ++vdso_data
->tb_update_count
;
789 void __init
clocksource_init(void)
791 struct clocksource
*clock
;
794 clock
= &clocksource_rtc
;
796 clock
= &clocksource_timebase
;
798 clock
->mult
= clocksource_hz2mult(tb_ticks_per_sec
, clock
->shift
);
800 if (clocksource_register(clock
)) {
801 printk(KERN_ERR
"clocksource: %s is already registered\n",
806 printk(KERN_INFO
"clocksource: %s mult[%x] shift[%d] registered\n",
807 clock
->name
, clock
->mult
, clock
->shift
);
810 static int decrementer_set_next_event(unsigned long evt
,
811 struct clock_event_device
*dev
)
813 __get_cpu_var(decrementer_next_tb
) = get_tb_or_rtc() + evt
;
818 static void decrementer_set_mode(enum clock_event_mode mode
,
819 struct clock_event_device
*dev
)
821 if (mode
!= CLOCK_EVT_MODE_ONESHOT
)
822 decrementer_set_next_event(DECREMENTER_MAX
, dev
);
825 static void register_decrementer_clockevent(int cpu
)
827 struct clock_event_device
*dec
= &per_cpu(decrementers
, cpu
);
829 *dec
= decrementer_clockevent
;
830 dec
->cpumask
= cpumask_of_cpu(cpu
);
832 printk(KERN_DEBUG
"clockevent: %s mult[%lx] shift[%d] cpu[%d]\n",
833 dec
->name
, dec
->mult
, dec
->shift
, cpu
);
835 clockevents_register_device(dec
);
838 static void __init
init_decrementer_clockevent(void)
840 int cpu
= smp_processor_id();
842 decrementer_clockevent
.mult
= div_sc(ppc_tb_freq
, NSEC_PER_SEC
,
843 decrementer_clockevent
.shift
);
844 decrementer_clockevent
.max_delta_ns
=
845 clockevent_delta2ns(DECREMENTER_MAX
, &decrementer_clockevent
);
846 decrementer_clockevent
.min_delta_ns
=
847 clockevent_delta2ns(2, &decrementer_clockevent
);
849 register_decrementer_clockevent(cpu
);
852 void secondary_cpu_time_init(void)
854 /* FIME: Should make unrelatred change to move snapshot_timebase
856 register_decrementer_clockevent(smp_processor_id());
859 /* This function is only called on the boot processor */
860 void __init
time_init(void)
863 struct div_result res
;
868 /* 601 processor: dec counts down by 128 every 128ns */
869 ppc_tb_freq
= 1000000000;
870 tb_last_jiffy
= get_rtcl();
872 /* Normal PowerPC with timebase register */
873 ppc_md
.calibrate_decr();
874 printk(KERN_DEBUG
"time_init: decrementer frequency = %lu.%.6lu MHz\n",
875 ppc_tb_freq
/ 1000000, ppc_tb_freq
% 1000000);
876 printk(KERN_DEBUG
"time_init: processor frequency = %lu.%.6lu MHz\n",
877 ppc_proc_freq
/ 1000000, ppc_proc_freq
% 1000000);
878 tb_last_jiffy
= get_tb();
881 tb_ticks_per_jiffy
= ppc_tb_freq
/ HZ
;
882 tb_ticks_per_sec
= ppc_tb_freq
;
883 tb_ticks_per_usec
= ppc_tb_freq
/ 1000000;
884 tb_to_us
= mulhwu_scale_factor(ppc_tb_freq
, 1000000);
885 calc_cputime_factors();
888 * Calculate the length of each tick in ns. It will not be
889 * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ.
890 * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq,
893 x
= (u64
) NSEC_PER_SEC
* tb_ticks_per_jiffy
+ ppc_tb_freq
- 1;
894 do_div(x
, ppc_tb_freq
);
896 last_tick_len
= x
<< TICKLEN_SCALE
;
899 * Compute ticklen_to_xs, which is a factor which gets multiplied
900 * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value.
902 * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9)
903 * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT
904 * which turns out to be N = 51 - SHIFT_HZ.
905 * This gives the result as a 0.64 fixed-point fraction.
906 * That value is reduced by an offset amounting to 1 xsec per
907 * 2^31 timebase ticks to avoid problems with time going backwards
908 * by 1 xsec when we do timer_recalc_offset due to losing the
909 * fractional xsec. That offset is equal to ppc_tb_freq/2^51
910 * since there are 2^20 xsec in a second.
912 div128_by_32((1ULL << 51) - ppc_tb_freq
, 0,
913 tb_ticks_per_jiffy
<< SHIFT_HZ
, &res
);
914 div128_by_32(res
.result_high
, res
.result_low
, NSEC_PER_SEC
, &res
);
915 ticklen_to_xs
= res
.result_low
;
917 /* Compute tb_to_xs from tick_nsec */
918 tb_to_xs
= mulhdu(last_tick_len
<< TICKLEN_SHIFT
, ticklen_to_xs
);
921 * Compute scale factor for sched_clock.
922 * The calibrate_decr() function has set tb_ticks_per_sec,
923 * which is the timebase frequency.
924 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
925 * the 128-bit result as a 64.64 fixed-point number.
926 * We then shift that number right until it is less than 1.0,
927 * giving us the scale factor and shift count to use in
930 div128_by_32(1000000000, 0, tb_ticks_per_sec
, &res
);
931 scale
= res
.result_low
;
932 for (shift
= 0; res
.result_high
!= 0; ++shift
) {
933 scale
= (scale
>> 1) | (res
.result_high
<< 63);
934 res
.result_high
>>= 1;
936 tb_to_ns_scale
= scale
;
937 tb_to_ns_shift
= shift
;
938 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
939 boot_tb
= get_tb_or_rtc();
941 write_seqlock_irqsave(&xtime_lock
, flags
);
943 /* If platform provided a timezone (pmac), we correct the time */
944 if (timezone_offset
) {
945 sys_tz
.tz_minuteswest
= -timezone_offset
/ 60;
946 sys_tz
.tz_dsttime
= 0;
949 do_gtod
.varp
= &do_gtod
.vars
[0];
951 do_gtod
.varp
->tb_orig_stamp
= tb_last_jiffy
;
952 __get_cpu_var(last_jiffy
) = tb_last_jiffy
;
953 do_gtod
.varp
->stamp_xsec
= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
954 do_gtod
.tb_ticks_per_sec
= tb_ticks_per_sec
;
955 do_gtod
.varp
->tb_to_xs
= tb_to_xs
;
956 do_gtod
.tb_to_us
= tb_to_us
;
958 vdso_data
->tb_orig_stamp
= tb_last_jiffy
;
959 vdso_data
->tb_update_count
= 0;
960 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
961 vdso_data
->stamp_xsec
= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
962 vdso_data
->tb_to_xs
= tb_to_xs
;
966 write_sequnlock_irqrestore(&xtime_lock
, flags
);
968 /* Register the clocksource, if we're not running on iSeries */
969 if (!firmware_has_feature(FW_FEATURE_ISERIES
))
972 init_decrementer_clockevent();
977 #define STARTOFTIME 1970
978 #define SECDAY 86400L
979 #define SECYR (SECDAY * 365)
980 #define leapyear(year) ((year) % 4 == 0 && \
981 ((year) % 100 != 0 || (year) % 400 == 0))
982 #define days_in_year(a) (leapyear(a) ? 366 : 365)
983 #define days_in_month(a) (month_days[(a) - 1])
985 static int month_days
[12] = {
986 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
990 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
992 void GregorianDay(struct rtc_time
* tm
)
997 int MonthOffset
[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
999 lastYear
= tm
->tm_year
- 1;
1002 * Number of leap corrections to apply up to end of last year
1004 leapsToDate
= lastYear
/ 4 - lastYear
/ 100 + lastYear
/ 400;
1007 * This year is a leap year if it is divisible by 4 except when it is
1008 * divisible by 100 unless it is divisible by 400
1010 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
1012 day
= tm
->tm_mon
> 2 && leapyear(tm
->tm_year
);
1014 day
+= lastYear
*365 + leapsToDate
+ MonthOffset
[tm
->tm_mon
-1] +
1017 tm
->tm_wday
= day
% 7;
1020 void to_tm(int tim
, struct rtc_time
* tm
)
1023 register long hms
, day
;
1028 /* Hours, minutes, seconds are easy */
1029 tm
->tm_hour
= hms
/ 3600;
1030 tm
->tm_min
= (hms
% 3600) / 60;
1031 tm
->tm_sec
= (hms
% 3600) % 60;
1033 /* Number of years in days */
1034 for (i
= STARTOFTIME
; day
>= days_in_year(i
); i
++)
1035 day
-= days_in_year(i
);
1038 /* Number of months in days left */
1039 if (leapyear(tm
->tm_year
))
1040 days_in_month(FEBRUARY
) = 29;
1041 for (i
= 1; day
>= days_in_month(i
); i
++)
1042 day
-= days_in_month(i
);
1043 days_in_month(FEBRUARY
) = 28;
1046 /* Days are what is left over (+1) from all that. */
1047 tm
->tm_mday
= day
+ 1;
1050 * Determine the day of week
1055 /* Auxiliary function to compute scaling factors */
1056 /* Actually the choice of a timebase running at 1/4 the of the bus
1057 * frequency giving resolution of a few tens of nanoseconds is quite nice.
1058 * It makes this computation very precise (27-28 bits typically) which
1059 * is optimistic considering the stability of most processor clock
1060 * oscillators and the precision with which the timebase frequency
1061 * is measured but does not harm.
1063 unsigned mulhwu_scale_factor(unsigned inscale
, unsigned outscale
)
1065 unsigned mlt
=0, tmp
, err
;
1066 /* No concern for performance, it's done once: use a stupid
1067 * but safe and compact method to find the multiplier.
1070 for (tmp
= 1U<<31; tmp
!= 0; tmp
>>= 1) {
1071 if (mulhwu(inscale
, mlt
|tmp
) < outscale
)
1075 /* We might still be off by 1 for the best approximation.
1076 * A side effect of this is that if outscale is too large
1077 * the returned value will be zero.
1078 * Many corner cases have been checked and seem to work,
1079 * some might have been forgotten in the test however.
1082 err
= inscale
* (mlt
+1);
1083 if (err
<= inscale
/2)
1089 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1092 void div128_by_32(u64 dividend_high
, u64 dividend_low
,
1093 unsigned divisor
, struct div_result
*dr
)
1095 unsigned long a
, b
, c
, d
;
1096 unsigned long w
, x
, y
, z
;
1099 a
= dividend_high
>> 32;
1100 b
= dividend_high
& 0xffffffff;
1101 c
= dividend_low
>> 32;
1102 d
= dividend_low
& 0xffffffff;
1105 ra
= ((u64
)(a
- (w
* divisor
)) << 32) + b
;
1107 rb
= ((u64
) do_div(ra
, divisor
) << 32) + c
;
1110 rc
= ((u64
) do_div(rb
, divisor
) << 32) + d
;
1113 do_div(rc
, divisor
);
1116 dr
->result_high
= ((u64
)w
<< 32) + x
;
1117 dr
->result_low
= ((u64
)y
<< 32) + z
;