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 #include <asm/cputime.h>
70 #ifdef CONFIG_PPC_ISERIES
71 #include <asm/iseries/it_lp_queue.h>
72 #include <asm/iseries/hv_call_xm.h>
75 /* powerpc clocksource/clockevent code */
77 #include <linux/clockchips.h>
78 #include <linux/clocksource.h>
80 static cycle_t
rtc_read(void);
81 static struct clocksource clocksource_rtc
= {
84 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
85 .mask
= CLOCKSOURCE_MASK(64),
87 .mult
= 0, /* To be filled in */
91 static cycle_t
timebase_read(void);
92 static struct clocksource clocksource_timebase
= {
95 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
96 .mask
= CLOCKSOURCE_MASK(64),
98 .mult
= 0, /* To be filled in */
99 .read
= timebase_read
,
102 #define DECREMENTER_MAX 0x7fffffff
104 static int decrementer_set_next_event(unsigned long evt
,
105 struct clock_event_device
*dev
);
106 static void decrementer_set_mode(enum clock_event_mode mode
,
107 struct clock_event_device
*dev
);
109 static struct clock_event_device decrementer_clockevent
= {
110 .name
= "decrementer",
113 .mult
= 0, /* To be filled in */
115 .set_next_event
= decrementer_set_next_event
,
116 .set_mode
= decrementer_set_mode
,
117 .features
= CLOCK_EVT_FEAT_ONESHOT
,
120 struct decrementer_clock
{
121 struct clock_event_device event
;
125 static DEFINE_PER_CPU(struct decrementer_clock
, decrementers
);
127 #ifdef CONFIG_PPC_ISERIES
128 static unsigned long __initdata iSeries_recal_titan
;
129 static signed long __initdata iSeries_recal_tb
;
131 /* Forward declaration is only needed for iSereis compiles */
132 static void __init
clocksource_init(void);
135 #define XSEC_PER_SEC (1024*1024)
138 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
140 /* compute ((xsec << 12) * max) >> 32 */
141 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
144 unsigned long tb_ticks_per_jiffy
;
145 unsigned long tb_ticks_per_usec
= 100; /* sane default */
146 EXPORT_SYMBOL(tb_ticks_per_usec
);
147 unsigned long tb_ticks_per_sec
;
148 EXPORT_SYMBOL(tb_ticks_per_sec
); /* for cputime_t conversions */
152 #define TICKLEN_SCALE NTP_SCALE_SHIFT
153 static u64 last_tick_len
; /* units are ns / 2^TICKLEN_SCALE */
154 static u64 ticklen_to_xs
; /* 0.64 fraction */
156 /* If last_tick_len corresponds to about 1/HZ seconds, then
157 last_tick_len << TICKLEN_SHIFT will be about 2^63. */
158 #define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ)
160 DEFINE_SPINLOCK(rtc_lock
);
161 EXPORT_SYMBOL_GPL(rtc_lock
);
163 static u64 tb_to_ns_scale __read_mostly
;
164 static unsigned tb_to_ns_shift __read_mostly
;
165 static unsigned long boot_tb __read_mostly
;
167 extern struct timezone sys_tz
;
168 static long timezone_offset
;
170 unsigned long ppc_proc_freq
;
171 EXPORT_SYMBOL(ppc_proc_freq
);
172 unsigned long ppc_tb_freq
;
174 static u64 tb_last_jiffy __cacheline_aligned_in_smp
;
175 static DEFINE_PER_CPU(u64
, last_jiffy
);
177 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
179 * Factors for converting from cputime_t (timebase ticks) to
180 * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds).
181 * These are all stored as 0.64 fixed-point binary fractions.
183 u64 __cputime_jiffies_factor
;
184 EXPORT_SYMBOL(__cputime_jiffies_factor
);
185 u64 __cputime_msec_factor
;
186 EXPORT_SYMBOL(__cputime_msec_factor
);
187 u64 __cputime_sec_factor
;
188 EXPORT_SYMBOL(__cputime_sec_factor
);
189 u64 __cputime_clockt_factor
;
190 EXPORT_SYMBOL(__cputime_clockt_factor
);
191 DEFINE_PER_CPU(unsigned long, cputime_last_delta
);
192 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta
);
194 static void calc_cputime_factors(void)
196 struct div_result res
;
198 div128_by_32(HZ
, 0, tb_ticks_per_sec
, &res
);
199 __cputime_jiffies_factor
= res
.result_low
;
200 div128_by_32(1000, 0, tb_ticks_per_sec
, &res
);
201 __cputime_msec_factor
= res
.result_low
;
202 div128_by_32(1, 0, tb_ticks_per_sec
, &res
);
203 __cputime_sec_factor
= res
.result_low
;
204 div128_by_32(USER_HZ
, 0, tb_ticks_per_sec
, &res
);
205 __cputime_clockt_factor
= res
.result_low
;
209 * Read the PURR on systems that have it, otherwise the timebase.
211 static u64
read_purr(void)
213 if (cpu_has_feature(CPU_FTR_PURR
))
214 return mfspr(SPRN_PURR
);
219 * Read the SPURR on systems that have it, otherwise the purr
221 static u64
read_spurr(u64 purr
)
224 * cpus without PURR won't have a SPURR
225 * We already know the former when we use this, so tell gcc
227 if (cpu_has_feature(CPU_FTR_PURR
) && cpu_has_feature(CPU_FTR_SPURR
))
228 return mfspr(SPRN_SPURR
);
233 * Account time for a transition between system, hard irq
236 void account_system_vtime(struct task_struct
*tsk
)
238 u64 now
, nowscaled
, delta
, deltascaled
, sys_time
;
241 local_irq_save(flags
);
243 nowscaled
= read_spurr(now
);
244 delta
= now
- get_paca()->startpurr
;
245 deltascaled
= nowscaled
- get_paca()->startspurr
;
246 get_paca()->startpurr
= now
;
247 get_paca()->startspurr
= nowscaled
;
248 if (!in_interrupt()) {
249 /* deltascaled includes both user and system time.
250 * Hence scale it based on the purr ratio to estimate
252 sys_time
= get_paca()->system_time
;
253 if (get_paca()->user_time
)
254 deltascaled
= deltascaled
* sys_time
/
255 (sys_time
+ get_paca()->user_time
);
257 get_paca()->system_time
= 0;
259 account_system_time(tsk
, 0, delta
);
260 account_system_time_scaled(tsk
, deltascaled
);
261 per_cpu(cputime_last_delta
, smp_processor_id()) = delta
;
262 per_cpu(cputime_scaled_last_delta
, smp_processor_id()) = deltascaled
;
263 local_irq_restore(flags
);
267 * Transfer the user and system times accumulated in the paca
268 * by the exception entry and exit code to the generic process
269 * user and system time records.
270 * Must be called with interrupts disabled.
272 void account_process_tick(struct task_struct
*tsk
, int user_tick
)
274 cputime_t utime
, utimescaled
;
276 utime
= get_paca()->user_time
;
277 get_paca()->user_time
= 0;
278 account_user_time(tsk
, utime
);
280 utimescaled
= cputime_to_scaled(utime
);
281 account_user_time_scaled(tsk
, utimescaled
);
285 * Stuff for accounting stolen time.
287 struct cpu_purr_data
{
288 int initialized
; /* thread is running */
289 u64 tb
; /* last TB value read */
290 u64 purr
; /* last PURR value read */
291 u64 spurr
; /* last SPURR value read */
295 * Each entry in the cpu_purr_data array is manipulated only by its
296 * "owner" cpu -- usually in the timer interrupt but also occasionally
297 * in process context for cpu online. As long as cpus do not touch
298 * each others' cpu_purr_data, disabling local interrupts is
299 * sufficient to serialize accesses.
301 static DEFINE_PER_CPU(struct cpu_purr_data
, cpu_purr_data
);
303 static void snapshot_tb_and_purr(void *data
)
306 struct cpu_purr_data
*p
= &__get_cpu_var(cpu_purr_data
);
308 local_irq_save(flags
);
309 p
->tb
= get_tb_or_rtc();
310 p
->purr
= mfspr(SPRN_PURR
);
313 local_irq_restore(flags
);
317 * Called during boot when all cpus have come up.
319 void snapshot_timebases(void)
321 if (!cpu_has_feature(CPU_FTR_PURR
))
323 on_each_cpu(snapshot_tb_and_purr
, NULL
, 1);
327 * Must be called with interrupts disabled.
329 void calculate_steal_time(void)
333 struct cpu_purr_data
*pme
;
335 pme
= &__get_cpu_var(cpu_purr_data
);
336 if (!pme
->initialized
)
337 return; /* !CPU_FTR_PURR or early in early boot */
339 purr
= mfspr(SPRN_PURR
);
340 stolen
= (tb
- pme
->tb
) - (purr
- pme
->purr
);
342 account_steal_time(current
, stolen
);
347 #ifdef CONFIG_PPC_SPLPAR
349 * Must be called before the cpu is added to the online map when
350 * a cpu is being brought up at runtime.
352 static void snapshot_purr(void)
354 struct cpu_purr_data
*pme
;
357 if (!cpu_has_feature(CPU_FTR_PURR
))
359 local_irq_save(flags
);
360 pme
= &__get_cpu_var(cpu_purr_data
);
362 pme
->purr
= mfspr(SPRN_PURR
);
363 pme
->initialized
= 1;
364 local_irq_restore(flags
);
367 #endif /* CONFIG_PPC_SPLPAR */
369 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
370 #define calc_cputime_factors()
371 #define calculate_steal_time() do { } while (0)
374 #if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR))
375 #define snapshot_purr() do { } while (0)
379 * Called when a cpu comes up after the system has finished booting,
380 * i.e. as a result of a hotplug cpu action.
382 void snapshot_timebase(void)
384 __get_cpu_var(last_jiffy
) = get_tb_or_rtc();
388 void __delay(unsigned long loops
)
396 /* the RTCL register wraps at 1000000000 */
397 diff
= get_rtcl() - start
;
400 } while (diff
< loops
);
403 while (get_tbl() - start
< loops
)
408 EXPORT_SYMBOL(__delay
);
410 void udelay(unsigned long usecs
)
412 __delay(tb_ticks_per_usec
* usecs
);
414 EXPORT_SYMBOL(udelay
);
416 static inline void update_gtod(u64 new_tb_stamp
, u64 new_stamp_xsec
,
420 * tb_update_count is used to allow the userspace gettimeofday code
421 * to assure itself that it sees a consistent view of the tb_to_xs and
422 * stamp_xsec variables. It reads the tb_update_count, then reads
423 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
424 * the two values of tb_update_count match and are even then the
425 * tb_to_xs and stamp_xsec values are consistent. If not, then it
426 * loops back and reads them again until this criteria is met.
427 * We expect the caller to have done the first increment of
428 * vdso_data->tb_update_count already.
430 vdso_data
->tb_orig_stamp
= new_tb_stamp
;
431 vdso_data
->stamp_xsec
= new_stamp_xsec
;
432 vdso_data
->tb_to_xs
= new_tb_to_xs
;
433 vdso_data
->wtom_clock_sec
= wall_to_monotonic
.tv_sec
;
434 vdso_data
->wtom_clock_nsec
= wall_to_monotonic
.tv_nsec
;
435 vdso_data
->stamp_xtime
= xtime
;
437 ++(vdso_data
->tb_update_count
);
441 unsigned long profile_pc(struct pt_regs
*regs
)
443 unsigned long pc
= instruction_pointer(regs
);
445 if (in_lock_functions(pc
))
450 EXPORT_SYMBOL(profile_pc
);
453 #ifdef CONFIG_PPC_ISERIES
456 * This function recalibrates the timebase based on the 49-bit time-of-day
457 * value in the Titan chip. The Titan is much more accurate than the value
458 * returned by the service processor for the timebase frequency.
461 static int __init
iSeries_tb_recal(void)
463 struct div_result divres
;
464 unsigned long titan
, tb
;
466 /* Make sure we only run on iSeries */
467 if (!firmware_has_feature(FW_FEATURE_ISERIES
))
471 titan
= HvCallXm_loadTod();
472 if ( iSeries_recal_titan
) {
473 unsigned long tb_ticks
= tb
- iSeries_recal_tb
;
474 unsigned long titan_usec
= (titan
- iSeries_recal_titan
) >> 12;
475 unsigned long new_tb_ticks_per_sec
= (tb_ticks
* USEC_PER_SEC
)/titan_usec
;
476 unsigned long new_tb_ticks_per_jiffy
= (new_tb_ticks_per_sec
+(HZ
/2))/HZ
;
477 long tick_diff
= new_tb_ticks_per_jiffy
- tb_ticks_per_jiffy
;
479 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */
480 new_tb_ticks_per_sec
= new_tb_ticks_per_jiffy
* HZ
;
482 if ( tick_diff
< 0 ) {
483 tick_diff
= -tick_diff
;
487 if ( tick_diff
< tb_ticks_per_jiffy
/25 ) {
488 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n",
489 new_tb_ticks_per_jiffy
, sign
, tick_diff
);
490 tb_ticks_per_jiffy
= new_tb_ticks_per_jiffy
;
491 tb_ticks_per_sec
= new_tb_ticks_per_sec
;
492 calc_cputime_factors();
493 div128_by_32( XSEC_PER_SEC
, 0, tb_ticks_per_sec
, &divres
);
494 tb_to_xs
= divres
.result_low
;
495 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
496 vdso_data
->tb_to_xs
= tb_to_xs
;
499 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n"
500 " new tb_ticks_per_jiffy = %lu\n"
501 " old tb_ticks_per_jiffy = %lu\n",
502 new_tb_ticks_per_jiffy
, tb_ticks_per_jiffy
);
506 iSeries_recal_titan
= titan
;
507 iSeries_recal_tb
= tb
;
509 /* Called here as now we know accurate values for the timebase */
513 late_initcall(iSeries_tb_recal
);
515 /* Called from platform early init */
516 void __init
iSeries_time_init_early(void)
518 iSeries_recal_tb
= get_tb();
519 iSeries_recal_titan
= HvCallXm_loadTod();
521 #endif /* CONFIG_PPC_ISERIES */
524 * For iSeries shared processors, we have to let the hypervisor
525 * set the hardware decrementer. We set a virtual decrementer
526 * in the lppaca and call the hypervisor if the virtual
527 * decrementer is less than the current value in the hardware
528 * decrementer. (almost always the new decrementer value will
529 * be greater than the current hardware decementer so the hypervisor
530 * call will not be needed)
534 * timer_interrupt - gets called when the decrementer overflows,
535 * with interrupts disabled.
537 void timer_interrupt(struct pt_regs
* regs
)
539 struct pt_regs
*old_regs
;
540 struct decrementer_clock
*decrementer
= &__get_cpu_var(decrementers
);
541 struct clock_event_device
*evt
= &decrementer
->event
;
544 /* Ensure a positive value is written to the decrementer, or else
545 * some CPUs will continuue to take decrementer exceptions */
546 set_dec(DECREMENTER_MAX
);
549 if (atomic_read(&ppc_n_lost_interrupts
) != 0)
553 now
= get_tb_or_rtc();
554 if (now
< decrementer
->next_tb
) {
555 /* not time for this event yet */
556 now
= decrementer
->next_tb
- now
;
557 if (now
<= DECREMENTER_MAX
)
561 old_regs
= set_irq_regs(regs
);
564 calculate_steal_time();
566 #ifdef CONFIG_PPC_ISERIES
567 if (firmware_has_feature(FW_FEATURE_ISERIES
))
568 get_lppaca()->int_dword
.fields
.decr_int
= 0;
571 if (evt
->event_handler
)
572 evt
->event_handler(evt
);
574 #ifdef CONFIG_PPC_ISERIES
575 if (firmware_has_feature(FW_FEATURE_ISERIES
) && hvlpevent_is_pending())
576 process_hvlpevents();
580 /* collect purr register values often, for accurate calculations */
581 if (firmware_has_feature(FW_FEATURE_SPLPAR
)) {
582 struct cpu_usage
*cu
= &__get_cpu_var(cpu_usage_array
);
583 cu
->current_tb
= mfspr(SPRN_PURR
);
588 set_irq_regs(old_regs
);
591 void wakeup_decrementer(void)
596 * The timebase gets saved on sleep and restored on wakeup,
597 * so all we need to do is to reset the decrementer.
599 ticks
= tb_ticks_since(__get_cpu_var(last_jiffy
));
600 if (ticks
< tb_ticks_per_jiffy
)
601 ticks
= tb_ticks_per_jiffy
- ticks
;
607 #ifdef CONFIG_SUSPEND
608 void generic_suspend_disable_irqs(void)
612 /* Disable the decrementer, so that it doesn't interfere
621 void generic_suspend_enable_irqs(void)
623 wakeup_decrementer();
629 /* Overrides the weak version in kernel/power/main.c */
630 void arch_suspend_disable_irqs(void)
632 if (ppc_md
.suspend_disable_irqs
)
633 ppc_md
.suspend_disable_irqs();
634 generic_suspend_disable_irqs();
637 /* Overrides the weak version in kernel/power/main.c */
638 void arch_suspend_enable_irqs(void)
640 generic_suspend_enable_irqs();
641 if (ppc_md
.suspend_enable_irqs
)
642 ppc_md
.suspend_enable_irqs();
647 void __init
smp_space_timers(unsigned int max_cpus
)
650 u64 previous_tb
= per_cpu(last_jiffy
, boot_cpuid
);
652 /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */
653 previous_tb
-= tb_ticks_per_jiffy
;
655 for_each_possible_cpu(i
) {
658 per_cpu(last_jiffy
, i
) = previous_tb
;
664 * Scheduler clock - returns current time in nanosec units.
666 * Note: mulhdu(a, b) (multiply high double unsigned) returns
667 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
668 * are 64-bit unsigned numbers.
670 unsigned long long sched_clock(void)
674 return mulhdu(get_tb() - boot_tb
, tb_to_ns_scale
) << tb_to_ns_shift
;
677 static int __init
get_freq(char *name
, int cells
, unsigned long *val
)
679 struct device_node
*cpu
;
680 const unsigned int *fp
;
683 /* The cpu node should have timebase and clock frequency properties */
684 cpu
= of_find_node_by_type(NULL
, "cpu");
687 fp
= of_get_property(cpu
, name
, NULL
);
690 *val
= of_read_ulong(fp
, cells
);
699 void __init
generic_calibrate_decr(void)
701 ppc_tb_freq
= DEFAULT_TB_FREQ
; /* hardcoded default */
703 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq
) &&
704 !get_freq("timebase-frequency", 1, &ppc_tb_freq
)) {
706 printk(KERN_ERR
"WARNING: Estimating decrementer frequency "
710 ppc_proc_freq
= DEFAULT_PROC_FREQ
; /* hardcoded default */
712 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq
) &&
713 !get_freq("clock-frequency", 1, &ppc_proc_freq
)) {
715 printk(KERN_ERR
"WARNING: Estimating processor frequency "
719 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
720 /* Clear any pending timer interrupts */
721 mtspr(SPRN_TSR
, TSR_ENW
| TSR_WIS
| TSR_DIS
| TSR_FIS
);
723 /* Enable decrementer interrupt */
724 mtspr(SPRN_TCR
, TCR_DIE
);
728 int update_persistent_clock(struct timespec now
)
732 if (!ppc_md
.set_rtc_time
)
735 to_tm(now
.tv_sec
+ 1 + timezone_offset
, &tm
);
739 return ppc_md
.set_rtc_time(&tm
);
742 unsigned long read_persistent_clock(void)
745 static int first
= 1;
747 /* XXX this is a litle fragile but will work okay in the short term */
750 if (ppc_md
.time_init
)
751 timezone_offset
= ppc_md
.time_init();
753 /* get_boot_time() isn't guaranteed to be safe to call late */
754 if (ppc_md
.get_boot_time
)
755 return ppc_md
.get_boot_time() -timezone_offset
;
757 if (!ppc_md
.get_rtc_time
)
759 ppc_md
.get_rtc_time(&tm
);
760 return mktime(tm
.tm_year
+1900, tm
.tm_mon
+1, tm
.tm_mday
,
761 tm
.tm_hour
, tm
.tm_min
, tm
.tm_sec
);
764 /* clocksource code */
765 static cycle_t
rtc_read(void)
767 return (cycle_t
)get_rtc();
770 static cycle_t
timebase_read(void)
772 return (cycle_t
)get_tb();
775 void update_vsyscall(struct timespec
*wall_time
, struct clocksource
*clock
)
779 if (clock
!= &clocksource_timebase
)
782 /* Make userspace gettimeofday spin until we're done. */
783 ++vdso_data
->tb_update_count
;
786 /* XXX this assumes clock->shift == 22 */
787 /* 4611686018 ~= 2^(20+64-22) / 1e9 */
788 t2x
= (u64
) clock
->mult
* 4611686018ULL;
789 stamp_xsec
= (u64
) xtime
.tv_nsec
* XSEC_PER_SEC
;
790 do_div(stamp_xsec
, 1000000000);
791 stamp_xsec
+= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
792 update_gtod(clock
->cycle_last
, stamp_xsec
, t2x
);
795 void update_vsyscall_tz(void)
797 /* Make userspace gettimeofday spin until we're done. */
798 ++vdso_data
->tb_update_count
;
800 vdso_data
->tz_minuteswest
= sys_tz
.tz_minuteswest
;
801 vdso_data
->tz_dsttime
= sys_tz
.tz_dsttime
;
803 ++vdso_data
->tb_update_count
;
806 static void __init
clocksource_init(void)
808 struct clocksource
*clock
;
811 clock
= &clocksource_rtc
;
813 clock
= &clocksource_timebase
;
815 clock
->mult
= clocksource_hz2mult(tb_ticks_per_sec
, clock
->shift
);
817 if (clocksource_register(clock
)) {
818 printk(KERN_ERR
"clocksource: %s is already registered\n",
823 printk(KERN_INFO
"clocksource: %s mult[%x] shift[%d] registered\n",
824 clock
->name
, clock
->mult
, clock
->shift
);
827 static int decrementer_set_next_event(unsigned long evt
,
828 struct clock_event_device
*dev
)
830 __get_cpu_var(decrementers
).next_tb
= get_tb_or_rtc() + evt
;
835 static void decrementer_set_mode(enum clock_event_mode mode
,
836 struct clock_event_device
*dev
)
838 if (mode
!= CLOCK_EVT_MODE_ONESHOT
)
839 decrementer_set_next_event(DECREMENTER_MAX
, dev
);
842 static void register_decrementer_clockevent(int cpu
)
844 struct clock_event_device
*dec
= &per_cpu(decrementers
, cpu
).event
;
846 *dec
= decrementer_clockevent
;
847 dec
->cpumask
= cpumask_of(cpu
);
849 printk(KERN_DEBUG
"clockevent: %s mult[%lx] shift[%d] cpu[%d]\n",
850 dec
->name
, dec
->mult
, dec
->shift
, cpu
);
852 clockevents_register_device(dec
);
855 static void __init
init_decrementer_clockevent(void)
857 int cpu
= smp_processor_id();
859 decrementer_clockevent
.mult
= div_sc(ppc_tb_freq
, NSEC_PER_SEC
,
860 decrementer_clockevent
.shift
);
861 decrementer_clockevent
.max_delta_ns
=
862 clockevent_delta2ns(DECREMENTER_MAX
, &decrementer_clockevent
);
863 decrementer_clockevent
.min_delta_ns
=
864 clockevent_delta2ns(2, &decrementer_clockevent
);
866 register_decrementer_clockevent(cpu
);
869 void secondary_cpu_time_init(void)
871 /* FIME: Should make unrelatred change to move snapshot_timebase
873 register_decrementer_clockevent(smp_processor_id());
876 /* This function is only called on the boot processor */
877 void __init
time_init(void)
880 struct div_result res
;
885 /* 601 processor: dec counts down by 128 every 128ns */
886 ppc_tb_freq
= 1000000000;
887 tb_last_jiffy
= get_rtcl();
889 /* Normal PowerPC with timebase register */
890 ppc_md
.calibrate_decr();
891 printk(KERN_DEBUG
"time_init: decrementer frequency = %lu.%.6lu MHz\n",
892 ppc_tb_freq
/ 1000000, ppc_tb_freq
% 1000000);
893 printk(KERN_DEBUG
"time_init: processor frequency = %lu.%.6lu MHz\n",
894 ppc_proc_freq
/ 1000000, ppc_proc_freq
% 1000000);
895 tb_last_jiffy
= get_tb();
898 tb_ticks_per_jiffy
= ppc_tb_freq
/ HZ
;
899 tb_ticks_per_sec
= ppc_tb_freq
;
900 tb_ticks_per_usec
= ppc_tb_freq
/ 1000000;
901 tb_to_us
= mulhwu_scale_factor(ppc_tb_freq
, 1000000);
902 calc_cputime_factors();
905 * Calculate the length of each tick in ns. It will not be
906 * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ.
907 * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq,
910 x
= (u64
) NSEC_PER_SEC
* tb_ticks_per_jiffy
+ ppc_tb_freq
- 1;
911 do_div(x
, ppc_tb_freq
);
913 last_tick_len
= x
<< TICKLEN_SCALE
;
916 * Compute ticklen_to_xs, which is a factor which gets multiplied
917 * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value.
919 * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9)
920 * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT
921 * which turns out to be N = 51 - SHIFT_HZ.
922 * This gives the result as a 0.64 fixed-point fraction.
923 * That value is reduced by an offset amounting to 1 xsec per
924 * 2^31 timebase ticks to avoid problems with time going backwards
925 * by 1 xsec when we do timer_recalc_offset due to losing the
926 * fractional xsec. That offset is equal to ppc_tb_freq/2^51
927 * since there are 2^20 xsec in a second.
929 div128_by_32((1ULL << 51) - ppc_tb_freq
, 0,
930 tb_ticks_per_jiffy
<< SHIFT_HZ
, &res
);
931 div128_by_32(res
.result_high
, res
.result_low
, NSEC_PER_SEC
, &res
);
932 ticklen_to_xs
= res
.result_low
;
934 /* Compute tb_to_xs from tick_nsec */
935 tb_to_xs
= mulhdu(last_tick_len
<< TICKLEN_SHIFT
, ticklen_to_xs
);
938 * Compute scale factor for sched_clock.
939 * The calibrate_decr() function has set tb_ticks_per_sec,
940 * which is the timebase frequency.
941 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
942 * the 128-bit result as a 64.64 fixed-point number.
943 * We then shift that number right until it is less than 1.0,
944 * giving us the scale factor and shift count to use in
947 div128_by_32(1000000000, 0, tb_ticks_per_sec
, &res
);
948 scale
= res
.result_low
;
949 for (shift
= 0; res
.result_high
!= 0; ++shift
) {
950 scale
= (scale
>> 1) | (res
.result_high
<< 63);
951 res
.result_high
>>= 1;
953 tb_to_ns_scale
= scale
;
954 tb_to_ns_shift
= shift
;
955 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
956 boot_tb
= get_tb_or_rtc();
958 write_seqlock_irqsave(&xtime_lock
, flags
);
960 /* If platform provided a timezone (pmac), we correct the time */
961 if (timezone_offset
) {
962 sys_tz
.tz_minuteswest
= -timezone_offset
/ 60;
963 sys_tz
.tz_dsttime
= 0;
966 vdso_data
->tb_orig_stamp
= tb_last_jiffy
;
967 vdso_data
->tb_update_count
= 0;
968 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
969 vdso_data
->stamp_xsec
= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
970 vdso_data
->tb_to_xs
= tb_to_xs
;
972 write_sequnlock_irqrestore(&xtime_lock
, flags
);
974 /* Register the clocksource, if we're not running on iSeries */
975 if (!firmware_has_feature(FW_FEATURE_ISERIES
))
978 init_decrementer_clockevent();
983 #define STARTOFTIME 1970
984 #define SECDAY 86400L
985 #define SECYR (SECDAY * 365)
986 #define leapyear(year) ((year) % 4 == 0 && \
987 ((year) % 100 != 0 || (year) % 400 == 0))
988 #define days_in_year(a) (leapyear(a) ? 366 : 365)
989 #define days_in_month(a) (month_days[(a) - 1])
991 static int month_days
[12] = {
992 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
996 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
998 void GregorianDay(struct rtc_time
* tm
)
1003 int MonthOffset
[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
1005 lastYear
= tm
->tm_year
- 1;
1008 * Number of leap corrections to apply up to end of last year
1010 leapsToDate
= lastYear
/ 4 - lastYear
/ 100 + lastYear
/ 400;
1013 * This year is a leap year if it is divisible by 4 except when it is
1014 * divisible by 100 unless it is divisible by 400
1016 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
1018 day
= tm
->tm_mon
> 2 && leapyear(tm
->tm_year
);
1020 day
+= lastYear
*365 + leapsToDate
+ MonthOffset
[tm
->tm_mon
-1] +
1023 tm
->tm_wday
= day
% 7;
1026 void to_tm(int tim
, struct rtc_time
* tm
)
1029 register long hms
, day
;
1034 /* Hours, minutes, seconds are easy */
1035 tm
->tm_hour
= hms
/ 3600;
1036 tm
->tm_min
= (hms
% 3600) / 60;
1037 tm
->tm_sec
= (hms
% 3600) % 60;
1039 /* Number of years in days */
1040 for (i
= STARTOFTIME
; day
>= days_in_year(i
); i
++)
1041 day
-= days_in_year(i
);
1044 /* Number of months in days left */
1045 if (leapyear(tm
->tm_year
))
1046 days_in_month(FEBRUARY
) = 29;
1047 for (i
= 1; day
>= days_in_month(i
); i
++)
1048 day
-= days_in_month(i
);
1049 days_in_month(FEBRUARY
) = 28;
1052 /* Days are what is left over (+1) from all that. */
1053 tm
->tm_mday
= day
+ 1;
1056 * Determine the day of week
1061 /* Auxiliary function to compute scaling factors */
1062 /* Actually the choice of a timebase running at 1/4 the of the bus
1063 * frequency giving resolution of a few tens of nanoseconds is quite nice.
1064 * It makes this computation very precise (27-28 bits typically) which
1065 * is optimistic considering the stability of most processor clock
1066 * oscillators and the precision with which the timebase frequency
1067 * is measured but does not harm.
1069 unsigned mulhwu_scale_factor(unsigned inscale
, unsigned outscale
)
1071 unsigned mlt
=0, tmp
, err
;
1072 /* No concern for performance, it's done once: use a stupid
1073 * but safe and compact method to find the multiplier.
1076 for (tmp
= 1U<<31; tmp
!= 0; tmp
>>= 1) {
1077 if (mulhwu(inscale
, mlt
|tmp
) < outscale
)
1081 /* We might still be off by 1 for the best approximation.
1082 * A side effect of this is that if outscale is too large
1083 * the returned value will be zero.
1084 * Many corner cases have been checked and seem to work,
1085 * some might have been forgotten in the test however.
1088 err
= inscale
* (mlt
+1);
1089 if (err
<= inscale
/2)
1095 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1098 void div128_by_32(u64 dividend_high
, u64 dividend_low
,
1099 unsigned divisor
, struct div_result
*dr
)
1101 unsigned long a
, b
, c
, d
;
1102 unsigned long w
, x
, y
, z
;
1105 a
= dividend_high
>> 32;
1106 b
= dividend_high
& 0xffffffff;
1107 c
= dividend_low
>> 32;
1108 d
= dividend_low
& 0xffffffff;
1111 ra
= ((u64
)(a
- (w
* divisor
)) << 32) + b
;
1113 rb
= ((u64
) do_div(ra
, divisor
) << 32) + c
;
1116 rc
= ((u64
) do_div(rb
, divisor
) << 32) + d
;
1119 do_div(rc
, divisor
);
1122 dr
->result_high
= ((u64
)w
<< 32) + x
;
1123 dr
->result_low
= ((u64
)y
<< 32) + z
;