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>
58 #include <asm/processor.h>
59 #include <asm/nvram.h>
60 #include <asm/cache.h>
61 #include <asm/machdep.h>
62 #include <asm/uaccess.h>
66 #include <asm/div64.h>
68 #include <asm/vdso_datapage.h>
69 #include <asm/firmware.h>
70 #include <asm/cputime.h>
71 #ifdef CONFIG_PPC_ISERIES
72 #include <asm/iseries/it_lp_queue.h>
73 #include <asm/iseries/hv_call_xm.h>
76 /* powerpc clocksource/clockevent code */
78 #include <linux/clockchips.h>
79 #include <linux/clocksource.h>
81 static cycle_t
rtc_read(struct clocksource
*);
82 static struct clocksource clocksource_rtc
= {
85 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
86 .mask
= CLOCKSOURCE_MASK(64),
88 .mult
= 0, /* To be filled in */
92 static cycle_t
timebase_read(struct clocksource
*);
93 static struct clocksource clocksource_timebase
= {
96 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
97 .mask
= CLOCKSOURCE_MASK(64),
99 .mult
= 0, /* To be filled in */
100 .read
= timebase_read
,
103 #define DECREMENTER_MAX 0x7fffffff
105 static int decrementer_set_next_event(unsigned long evt
,
106 struct clock_event_device
*dev
);
107 static void decrementer_set_mode(enum clock_event_mode mode
,
108 struct clock_event_device
*dev
);
110 static struct clock_event_device decrementer_clockevent
= {
111 .name
= "decrementer",
113 .shift
= 0, /* To be filled in */
114 .mult
= 0, /* To be filled in */
116 .set_next_event
= decrementer_set_next_event
,
117 .set_mode
= decrementer_set_mode
,
118 .features
= CLOCK_EVT_FEAT_ONESHOT
,
121 struct decrementer_clock
{
122 struct clock_event_device event
;
126 static DEFINE_PER_CPU(struct decrementer_clock
, decrementers
);
128 #ifdef CONFIG_PPC_ISERIES
129 static unsigned long __initdata iSeries_recal_titan
;
130 static signed long __initdata iSeries_recal_tb
;
132 /* Forward declaration is only needed for iSereis compiles */
133 static void __init
clocksource_init(void);
136 #define XSEC_PER_SEC (1024*1024)
139 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
141 /* compute ((xsec << 12) * max) >> 32 */
142 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
145 unsigned long tb_ticks_per_jiffy
;
146 unsigned long tb_ticks_per_usec
= 100; /* sane default */
147 EXPORT_SYMBOL(tb_ticks_per_usec
);
148 unsigned long tb_ticks_per_sec
;
149 EXPORT_SYMBOL(tb_ticks_per_sec
); /* for cputime_t conversions */
153 #define TICKLEN_SCALE NTP_SCALE_SHIFT
154 static u64 last_tick_len
; /* units are ns / 2^TICKLEN_SCALE */
155 static u64 ticklen_to_xs
; /* 0.64 fraction */
157 /* If last_tick_len corresponds to about 1/HZ seconds, then
158 last_tick_len << TICKLEN_SHIFT will be about 2^63. */
159 #define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ)
161 DEFINE_SPINLOCK(rtc_lock
);
162 EXPORT_SYMBOL_GPL(rtc_lock
);
164 static u64 tb_to_ns_scale __read_mostly
;
165 static unsigned tb_to_ns_shift __read_mostly
;
166 static unsigned long boot_tb __read_mostly
;
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
);
192 DEFINE_PER_CPU(unsigned long, cputime_last_delta
);
193 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta
);
195 static void calc_cputime_factors(void)
197 struct div_result res
;
199 div128_by_32(HZ
, 0, tb_ticks_per_sec
, &res
);
200 __cputime_jiffies_factor
= res
.result_low
;
201 div128_by_32(1000, 0, tb_ticks_per_sec
, &res
);
202 __cputime_msec_factor
= res
.result_low
;
203 div128_by_32(1, 0, tb_ticks_per_sec
, &res
);
204 __cputime_sec_factor
= res
.result_low
;
205 div128_by_32(USER_HZ
, 0, tb_ticks_per_sec
, &res
);
206 __cputime_clockt_factor
= res
.result_low
;
210 * Read the PURR on systems that have it, otherwise the timebase.
212 static u64
read_purr(void)
214 if (cpu_has_feature(CPU_FTR_PURR
))
215 return mfspr(SPRN_PURR
);
220 * Read the SPURR on systems that have it, otherwise the purr
222 static u64
read_spurr(u64 purr
)
225 * cpus without PURR won't have a SPURR
226 * We already know the former when we use this, so tell gcc
228 if (cpu_has_feature(CPU_FTR_PURR
) && cpu_has_feature(CPU_FTR_SPURR
))
229 return mfspr(SPRN_SPURR
);
234 * Account time for a transition between system, hard irq
237 void account_system_vtime(struct task_struct
*tsk
)
239 u64 now
, nowscaled
, delta
, deltascaled
, sys_time
;
242 local_irq_save(flags
);
244 nowscaled
= read_spurr(now
);
245 delta
= now
- get_paca()->startpurr
;
246 deltascaled
= nowscaled
- get_paca()->startspurr
;
247 get_paca()->startpurr
= now
;
248 get_paca()->startspurr
= nowscaled
;
249 if (!in_interrupt()) {
250 /* deltascaled includes both user and system time.
251 * Hence scale it based on the purr ratio to estimate
253 sys_time
= get_paca()->system_time
;
254 if (get_paca()->user_time
)
255 deltascaled
= deltascaled
* sys_time
/
256 (sys_time
+ get_paca()->user_time
);
258 get_paca()->system_time
= 0;
260 if (in_irq() || idle_task(smp_processor_id()) != tsk
)
261 account_system_time(tsk
, 0, delta
, deltascaled
);
263 account_idle_time(delta
);
264 per_cpu(cputime_last_delta
, smp_processor_id()) = delta
;
265 per_cpu(cputime_scaled_last_delta
, smp_processor_id()) = deltascaled
;
266 local_irq_restore(flags
);
270 * Transfer the user and system times accumulated in the paca
271 * by the exception entry and exit code to the generic process
272 * user and system time records.
273 * Must be called with interrupts disabled.
275 void account_process_tick(struct task_struct
*tsk
, int user_tick
)
277 cputime_t utime
, utimescaled
;
279 utime
= get_paca()->user_time
;
280 get_paca()->user_time
= 0;
281 utimescaled
= cputime_to_scaled(utime
);
282 account_user_time(tsk
, utime
, utimescaled
);
286 * Stuff for accounting stolen time.
288 struct cpu_purr_data
{
289 int initialized
; /* thread is running */
290 u64 tb
; /* last TB value read */
291 u64 purr
; /* last PURR value read */
292 u64 spurr
; /* last SPURR value read */
296 * Each entry in the cpu_purr_data array is manipulated only by its
297 * "owner" cpu -- usually in the timer interrupt but also occasionally
298 * in process context for cpu online. As long as cpus do not touch
299 * each others' cpu_purr_data, disabling local interrupts is
300 * sufficient to serialize accesses.
302 static DEFINE_PER_CPU(struct cpu_purr_data
, cpu_purr_data
);
304 static void snapshot_tb_and_purr(void *data
)
307 struct cpu_purr_data
*p
= &__get_cpu_var(cpu_purr_data
);
309 local_irq_save(flags
);
310 p
->tb
= get_tb_or_rtc();
311 p
->purr
= mfspr(SPRN_PURR
);
314 local_irq_restore(flags
);
318 * Called during boot when all cpus have come up.
320 void snapshot_timebases(void)
322 if (!cpu_has_feature(CPU_FTR_PURR
))
324 on_each_cpu(snapshot_tb_and_purr
, NULL
, 1);
328 * Must be called with interrupts disabled.
330 void calculate_steal_time(void)
334 struct cpu_purr_data
*pme
;
336 pme
= &__get_cpu_var(cpu_purr_data
);
337 if (!pme
->initialized
)
338 return; /* !CPU_FTR_PURR or early in early boot */
340 purr
= mfspr(SPRN_PURR
);
341 stolen
= (tb
- pme
->tb
) - (purr
- pme
->purr
);
343 if (idle_task(smp_processor_id()) != current
)
344 account_steal_time(stolen
);
346 account_idle_time(stolen
);
352 #ifdef CONFIG_PPC_SPLPAR
354 * Must be called before the cpu is added to the online map when
355 * a cpu is being brought up at runtime.
357 static void snapshot_purr(void)
359 struct cpu_purr_data
*pme
;
362 if (!cpu_has_feature(CPU_FTR_PURR
))
364 local_irq_save(flags
);
365 pme
= &__get_cpu_var(cpu_purr_data
);
367 pme
->purr
= mfspr(SPRN_PURR
);
368 pme
->initialized
= 1;
369 local_irq_restore(flags
);
372 #endif /* CONFIG_PPC_SPLPAR */
374 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
375 #define calc_cputime_factors()
376 #define calculate_steal_time() do { } while (0)
379 #if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR))
380 #define snapshot_purr() do { } while (0)
384 * Called when a cpu comes up after the system has finished booting,
385 * i.e. as a result of a hotplug cpu action.
387 void snapshot_timebase(void)
389 __get_cpu_var(last_jiffy
) = get_tb_or_rtc();
393 void __delay(unsigned long loops
)
401 /* the RTCL register wraps at 1000000000 */
402 diff
= get_rtcl() - start
;
405 } while (diff
< loops
);
408 while (get_tbl() - start
< loops
)
413 EXPORT_SYMBOL(__delay
);
415 void udelay(unsigned long usecs
)
417 __delay(tb_ticks_per_usec
* usecs
);
419 EXPORT_SYMBOL(udelay
);
421 static inline void update_gtod(u64 new_tb_stamp
, u64 new_stamp_xsec
,
425 * tb_update_count is used to allow the userspace gettimeofday code
426 * to assure itself that it sees a consistent view of the tb_to_xs and
427 * stamp_xsec variables. It reads the tb_update_count, then reads
428 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
429 * the two values of tb_update_count match and are even then the
430 * tb_to_xs and stamp_xsec values are consistent. If not, then it
431 * loops back and reads them again until this criteria is met.
432 * We expect the caller to have done the first increment of
433 * vdso_data->tb_update_count already.
435 vdso_data
->tb_orig_stamp
= new_tb_stamp
;
436 vdso_data
->stamp_xsec
= new_stamp_xsec
;
437 vdso_data
->tb_to_xs
= new_tb_to_xs
;
438 vdso_data
->wtom_clock_sec
= wall_to_monotonic
.tv_sec
;
439 vdso_data
->wtom_clock_nsec
= wall_to_monotonic
.tv_nsec
;
440 vdso_data
->stamp_xtime
= xtime
;
442 ++(vdso_data
->tb_update_count
);
446 unsigned long profile_pc(struct pt_regs
*regs
)
448 unsigned long pc
= instruction_pointer(regs
);
450 if (in_lock_functions(pc
))
455 EXPORT_SYMBOL(profile_pc
);
458 #ifdef CONFIG_PPC_ISERIES
461 * This function recalibrates the timebase based on the 49-bit time-of-day
462 * value in the Titan chip. The Titan is much more accurate than the value
463 * returned by the service processor for the timebase frequency.
466 static int __init
iSeries_tb_recal(void)
468 struct div_result divres
;
469 unsigned long titan
, tb
;
471 /* Make sure we only run on iSeries */
472 if (!firmware_has_feature(FW_FEATURE_ISERIES
))
476 titan
= HvCallXm_loadTod();
477 if ( iSeries_recal_titan
) {
478 unsigned long tb_ticks
= tb
- iSeries_recal_tb
;
479 unsigned long titan_usec
= (titan
- iSeries_recal_titan
) >> 12;
480 unsigned long new_tb_ticks_per_sec
= (tb_ticks
* USEC_PER_SEC
)/titan_usec
;
481 unsigned long new_tb_ticks_per_jiffy
= (new_tb_ticks_per_sec
+(HZ
/2))/HZ
;
482 long tick_diff
= new_tb_ticks_per_jiffy
- tb_ticks_per_jiffy
;
484 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */
485 new_tb_ticks_per_sec
= new_tb_ticks_per_jiffy
* HZ
;
487 if ( tick_diff
< 0 ) {
488 tick_diff
= -tick_diff
;
492 if ( tick_diff
< tb_ticks_per_jiffy
/25 ) {
493 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n",
494 new_tb_ticks_per_jiffy
, sign
, tick_diff
);
495 tb_ticks_per_jiffy
= new_tb_ticks_per_jiffy
;
496 tb_ticks_per_sec
= new_tb_ticks_per_sec
;
497 calc_cputime_factors();
498 div128_by_32( XSEC_PER_SEC
, 0, tb_ticks_per_sec
, &divres
);
499 tb_to_xs
= divres
.result_low
;
500 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
501 vdso_data
->tb_to_xs
= tb_to_xs
;
504 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n"
505 " new tb_ticks_per_jiffy = %lu\n"
506 " old tb_ticks_per_jiffy = %lu\n",
507 new_tb_ticks_per_jiffy
, tb_ticks_per_jiffy
);
511 iSeries_recal_titan
= titan
;
512 iSeries_recal_tb
= tb
;
514 /* Called here as now we know accurate values for the timebase */
518 late_initcall(iSeries_tb_recal
);
520 /* Called from platform early init */
521 void __init
iSeries_time_init_early(void)
523 iSeries_recal_tb
= get_tb();
524 iSeries_recal_titan
= HvCallXm_loadTod();
526 #endif /* CONFIG_PPC_ISERIES */
529 * For iSeries shared processors, we have to let the hypervisor
530 * set the hardware decrementer. We set a virtual decrementer
531 * in the lppaca and call the hypervisor if the virtual
532 * decrementer is less than the current value in the hardware
533 * decrementer. (almost always the new decrementer value will
534 * be greater than the current hardware decementer so the hypervisor
535 * call will not be needed)
539 * timer_interrupt - gets called when the decrementer overflows,
540 * with interrupts disabled.
542 void timer_interrupt(struct pt_regs
* regs
)
544 struct pt_regs
*old_regs
;
545 struct decrementer_clock
*decrementer
= &__get_cpu_var(decrementers
);
546 struct clock_event_device
*evt
= &decrementer
->event
;
549 /* Ensure a positive value is written to the decrementer, or else
550 * some CPUs will continuue to take decrementer exceptions */
551 set_dec(DECREMENTER_MAX
);
554 if (atomic_read(&ppc_n_lost_interrupts
) != 0)
558 now
= get_tb_or_rtc();
559 if (now
< decrementer
->next_tb
) {
560 /* not time for this event yet */
561 now
= decrementer
->next_tb
- now
;
562 if (now
<= DECREMENTER_MAX
)
566 old_regs
= set_irq_regs(regs
);
569 calculate_steal_time();
571 #ifdef CONFIG_PPC_ISERIES
572 if (firmware_has_feature(FW_FEATURE_ISERIES
))
573 get_lppaca()->int_dword
.fields
.decr_int
= 0;
576 if (evt
->event_handler
)
577 evt
->event_handler(evt
);
579 #ifdef CONFIG_PPC_ISERIES
580 if (firmware_has_feature(FW_FEATURE_ISERIES
) && hvlpevent_is_pending())
581 process_hvlpevents();
585 /* collect purr register values often, for accurate calculations */
586 if (firmware_has_feature(FW_FEATURE_SPLPAR
)) {
587 struct cpu_usage
*cu
= &__get_cpu_var(cpu_usage_array
);
588 cu
->current_tb
= mfspr(SPRN_PURR
);
593 set_irq_regs(old_regs
);
596 void wakeup_decrementer(void)
601 * The timebase gets saved on sleep and restored on wakeup,
602 * so all we need to do is to reset the decrementer.
604 ticks
= tb_ticks_since(__get_cpu_var(last_jiffy
));
605 if (ticks
< tb_ticks_per_jiffy
)
606 ticks
= tb_ticks_per_jiffy
- ticks
;
612 #ifdef CONFIG_SUSPEND
613 void generic_suspend_disable_irqs(void)
617 /* Disable the decrementer, so that it doesn't interfere
626 void generic_suspend_enable_irqs(void)
628 wakeup_decrementer();
634 /* Overrides the weak version in kernel/power/main.c */
635 void arch_suspend_disable_irqs(void)
637 if (ppc_md
.suspend_disable_irqs
)
638 ppc_md
.suspend_disable_irqs();
639 generic_suspend_disable_irqs();
642 /* Overrides the weak version in kernel/power/main.c */
643 void arch_suspend_enable_irqs(void)
645 generic_suspend_enable_irqs();
646 if (ppc_md
.suspend_enable_irqs
)
647 ppc_md
.suspend_enable_irqs();
652 void __init
smp_space_timers(unsigned int max_cpus
)
655 u64 previous_tb
= per_cpu(last_jiffy
, boot_cpuid
);
657 /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */
658 previous_tb
-= tb_ticks_per_jiffy
;
660 for_each_possible_cpu(i
) {
663 per_cpu(last_jiffy
, i
) = previous_tb
;
669 * Scheduler clock - returns current time in nanosec units.
671 * Note: mulhdu(a, b) (multiply high double unsigned) returns
672 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
673 * are 64-bit unsigned numbers.
675 unsigned long long sched_clock(void)
679 return mulhdu(get_tb() - boot_tb
, tb_to_ns_scale
) << tb_to_ns_shift
;
682 static int __init
get_freq(char *name
, int cells
, unsigned long *val
)
684 struct device_node
*cpu
;
685 const unsigned int *fp
;
688 /* The cpu node should have timebase and clock frequency properties */
689 cpu
= of_find_node_by_type(NULL
, "cpu");
692 fp
= of_get_property(cpu
, name
, NULL
);
695 *val
= of_read_ulong(fp
, cells
);
704 void __init
generic_calibrate_decr(void)
706 ppc_tb_freq
= DEFAULT_TB_FREQ
; /* hardcoded default */
708 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq
) &&
709 !get_freq("timebase-frequency", 1, &ppc_tb_freq
)) {
711 printk(KERN_ERR
"WARNING: Estimating decrementer frequency "
715 ppc_proc_freq
= DEFAULT_PROC_FREQ
; /* hardcoded default */
717 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq
) &&
718 !get_freq("clock-frequency", 1, &ppc_proc_freq
)) {
720 printk(KERN_ERR
"WARNING: Estimating processor frequency "
724 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
725 /* Clear any pending timer interrupts */
726 mtspr(SPRN_TSR
, TSR_ENW
| TSR_WIS
| TSR_DIS
| TSR_FIS
);
728 /* Enable decrementer interrupt */
729 mtspr(SPRN_TCR
, TCR_DIE
);
733 int update_persistent_clock(struct timespec now
)
737 if (!ppc_md
.set_rtc_time
)
740 to_tm(now
.tv_sec
+ 1 + timezone_offset
, &tm
);
744 return ppc_md
.set_rtc_time(&tm
);
747 unsigned long read_persistent_clock(void)
750 static int first
= 1;
752 /* XXX this is a litle fragile but will work okay in the short term */
755 if (ppc_md
.time_init
)
756 timezone_offset
= ppc_md
.time_init();
758 /* get_boot_time() isn't guaranteed to be safe to call late */
759 if (ppc_md
.get_boot_time
)
760 return ppc_md
.get_boot_time() -timezone_offset
;
762 if (!ppc_md
.get_rtc_time
)
764 ppc_md
.get_rtc_time(&tm
);
765 return mktime(tm
.tm_year
+1900, tm
.tm_mon
+1, tm
.tm_mday
,
766 tm
.tm_hour
, tm
.tm_min
, tm
.tm_sec
);
769 /* clocksource code */
770 static cycle_t
rtc_read(struct clocksource
*cs
)
772 return (cycle_t
)get_rtc();
775 static cycle_t
timebase_read(struct clocksource
*cs
)
777 return (cycle_t
)get_tb();
780 void update_vsyscall(struct timespec
*wall_time
, struct clocksource
*clock
)
784 if (clock
!= &clocksource_timebase
)
787 /* Make userspace gettimeofday spin until we're done. */
788 ++vdso_data
->tb_update_count
;
791 /* XXX this assumes clock->shift == 22 */
792 /* 4611686018 ~= 2^(20+64-22) / 1e9 */
793 t2x
= (u64
) clock
->mult
* 4611686018ULL;
794 stamp_xsec
= (u64
) xtime
.tv_nsec
* XSEC_PER_SEC
;
795 do_div(stamp_xsec
, 1000000000);
796 stamp_xsec
+= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
797 update_gtod(clock
->cycle_last
, stamp_xsec
, t2x
);
800 void update_vsyscall_tz(void)
802 /* Make userspace gettimeofday spin until we're done. */
803 ++vdso_data
->tb_update_count
;
805 vdso_data
->tz_minuteswest
= sys_tz
.tz_minuteswest
;
806 vdso_data
->tz_dsttime
= sys_tz
.tz_dsttime
;
808 ++vdso_data
->tb_update_count
;
811 static void __init
clocksource_init(void)
813 struct clocksource
*clock
;
816 clock
= &clocksource_rtc
;
818 clock
= &clocksource_timebase
;
820 clock
->mult
= clocksource_hz2mult(tb_ticks_per_sec
, clock
->shift
);
822 if (clocksource_register(clock
)) {
823 printk(KERN_ERR
"clocksource: %s is already registered\n",
828 printk(KERN_INFO
"clocksource: %s mult[%x] shift[%d] registered\n",
829 clock
->name
, clock
->mult
, clock
->shift
);
832 static int decrementer_set_next_event(unsigned long evt
,
833 struct clock_event_device
*dev
)
835 __get_cpu_var(decrementers
).next_tb
= get_tb_or_rtc() + evt
;
840 static void decrementer_set_mode(enum clock_event_mode mode
,
841 struct clock_event_device
*dev
)
843 if (mode
!= CLOCK_EVT_MODE_ONESHOT
)
844 decrementer_set_next_event(DECREMENTER_MAX
, dev
);
847 static void __init
setup_clockevent_multiplier(unsigned long hz
)
849 u64 mult
, shift
= 32;
852 mult
= div_sc(hz
, NSEC_PER_SEC
, shift
);
853 if (mult
&& (mult
>> 32UL) == 0UL)
859 decrementer_clockevent
.shift
= shift
;
860 decrementer_clockevent
.mult
= mult
;
863 static void register_decrementer_clockevent(int cpu
)
865 struct clock_event_device
*dec
= &per_cpu(decrementers
, cpu
).event
;
867 *dec
= decrementer_clockevent
;
868 dec
->cpumask
= cpumask_of(cpu
);
870 printk(KERN_DEBUG
"clockevent: %s mult[%lx] shift[%d] cpu[%d]\n",
871 dec
->name
, dec
->mult
, dec
->shift
, cpu
);
873 clockevents_register_device(dec
);
876 static void __init
init_decrementer_clockevent(void)
878 int cpu
= smp_processor_id();
880 setup_clockevent_multiplier(ppc_tb_freq
);
881 decrementer_clockevent
.max_delta_ns
=
882 clockevent_delta2ns(DECREMENTER_MAX
, &decrementer_clockevent
);
883 decrementer_clockevent
.min_delta_ns
=
884 clockevent_delta2ns(2, &decrementer_clockevent
);
886 register_decrementer_clockevent(cpu
);
889 void secondary_cpu_time_init(void)
891 /* FIME: Should make unrelatred change to move snapshot_timebase
893 register_decrementer_clockevent(smp_processor_id());
896 /* This function is only called on the boot processor */
897 void __init
time_init(void)
900 struct div_result res
;
905 /* 601 processor: dec counts down by 128 every 128ns */
906 ppc_tb_freq
= 1000000000;
907 tb_last_jiffy
= get_rtcl();
909 /* Normal PowerPC with timebase register */
910 ppc_md
.calibrate_decr();
911 printk(KERN_DEBUG
"time_init: decrementer frequency = %lu.%.6lu MHz\n",
912 ppc_tb_freq
/ 1000000, ppc_tb_freq
% 1000000);
913 printk(KERN_DEBUG
"time_init: processor frequency = %lu.%.6lu MHz\n",
914 ppc_proc_freq
/ 1000000, ppc_proc_freq
% 1000000);
915 tb_last_jiffy
= get_tb();
918 tb_ticks_per_jiffy
= ppc_tb_freq
/ HZ
;
919 tb_ticks_per_sec
= ppc_tb_freq
;
920 tb_ticks_per_usec
= ppc_tb_freq
/ 1000000;
921 tb_to_us
= mulhwu_scale_factor(ppc_tb_freq
, 1000000);
922 calc_cputime_factors();
925 * Calculate the length of each tick in ns. It will not be
926 * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ.
927 * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq,
930 x
= (u64
) NSEC_PER_SEC
* tb_ticks_per_jiffy
+ ppc_tb_freq
- 1;
931 do_div(x
, ppc_tb_freq
);
933 last_tick_len
= x
<< TICKLEN_SCALE
;
936 * Compute ticklen_to_xs, which is a factor which gets multiplied
937 * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value.
939 * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9)
940 * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT
941 * which turns out to be N = 51 - SHIFT_HZ.
942 * This gives the result as a 0.64 fixed-point fraction.
943 * That value is reduced by an offset amounting to 1 xsec per
944 * 2^31 timebase ticks to avoid problems with time going backwards
945 * by 1 xsec when we do timer_recalc_offset due to losing the
946 * fractional xsec. That offset is equal to ppc_tb_freq/2^51
947 * since there are 2^20 xsec in a second.
949 div128_by_32((1ULL << 51) - ppc_tb_freq
, 0,
950 tb_ticks_per_jiffy
<< SHIFT_HZ
, &res
);
951 div128_by_32(res
.result_high
, res
.result_low
, NSEC_PER_SEC
, &res
);
952 ticklen_to_xs
= res
.result_low
;
954 /* Compute tb_to_xs from tick_nsec */
955 tb_to_xs
= mulhdu(last_tick_len
<< TICKLEN_SHIFT
, ticklen_to_xs
);
958 * Compute scale factor for sched_clock.
959 * The calibrate_decr() function has set tb_ticks_per_sec,
960 * which is the timebase frequency.
961 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
962 * the 128-bit result as a 64.64 fixed-point number.
963 * We then shift that number right until it is less than 1.0,
964 * giving us the scale factor and shift count to use in
967 div128_by_32(1000000000, 0, tb_ticks_per_sec
, &res
);
968 scale
= res
.result_low
;
969 for (shift
= 0; res
.result_high
!= 0; ++shift
) {
970 scale
= (scale
>> 1) | (res
.result_high
<< 63);
971 res
.result_high
>>= 1;
973 tb_to_ns_scale
= scale
;
974 tb_to_ns_shift
= shift
;
975 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
976 boot_tb
= get_tb_or_rtc();
978 write_seqlock_irqsave(&xtime_lock
, flags
);
980 /* If platform provided a timezone (pmac), we correct the time */
981 if (timezone_offset
) {
982 sys_tz
.tz_minuteswest
= -timezone_offset
/ 60;
983 sys_tz
.tz_dsttime
= 0;
986 vdso_data
->tb_orig_stamp
= tb_last_jiffy
;
987 vdso_data
->tb_update_count
= 0;
988 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
989 vdso_data
->stamp_xsec
= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
990 vdso_data
->tb_to_xs
= tb_to_xs
;
992 write_sequnlock_irqrestore(&xtime_lock
, flags
);
994 /* Register the clocksource, if we're not running on iSeries */
995 if (!firmware_has_feature(FW_FEATURE_ISERIES
))
998 init_decrementer_clockevent();
1003 #define STARTOFTIME 1970
1004 #define SECDAY 86400L
1005 #define SECYR (SECDAY * 365)
1006 #define leapyear(year) ((year) % 4 == 0 && \
1007 ((year) % 100 != 0 || (year) % 400 == 0))
1008 #define days_in_year(a) (leapyear(a) ? 366 : 365)
1009 #define days_in_month(a) (month_days[(a) - 1])
1011 static int month_days
[12] = {
1012 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
1016 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
1018 void GregorianDay(struct rtc_time
* tm
)
1023 int MonthOffset
[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
1025 lastYear
= tm
->tm_year
- 1;
1028 * Number of leap corrections to apply up to end of last year
1030 leapsToDate
= lastYear
/ 4 - lastYear
/ 100 + lastYear
/ 400;
1033 * This year is a leap year if it is divisible by 4 except when it is
1034 * divisible by 100 unless it is divisible by 400
1036 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
1038 day
= tm
->tm_mon
> 2 && leapyear(tm
->tm_year
);
1040 day
+= lastYear
*365 + leapsToDate
+ MonthOffset
[tm
->tm_mon
-1] +
1043 tm
->tm_wday
= day
% 7;
1046 void to_tm(int tim
, struct rtc_time
* tm
)
1049 register long hms
, day
;
1054 /* Hours, minutes, seconds are easy */
1055 tm
->tm_hour
= hms
/ 3600;
1056 tm
->tm_min
= (hms
% 3600) / 60;
1057 tm
->tm_sec
= (hms
% 3600) % 60;
1059 /* Number of years in days */
1060 for (i
= STARTOFTIME
; day
>= days_in_year(i
); i
++)
1061 day
-= days_in_year(i
);
1064 /* Number of months in days left */
1065 if (leapyear(tm
->tm_year
))
1066 days_in_month(FEBRUARY
) = 29;
1067 for (i
= 1; day
>= days_in_month(i
); i
++)
1068 day
-= days_in_month(i
);
1069 days_in_month(FEBRUARY
) = 28;
1072 /* Days are what is left over (+1) from all that. */
1073 tm
->tm_mday
= day
+ 1;
1076 * Determine the day of week
1081 /* Auxiliary function to compute scaling factors */
1082 /* Actually the choice of a timebase running at 1/4 the of the bus
1083 * frequency giving resolution of a few tens of nanoseconds is quite nice.
1084 * It makes this computation very precise (27-28 bits typically) which
1085 * is optimistic considering the stability of most processor clock
1086 * oscillators and the precision with which the timebase frequency
1087 * is measured but does not harm.
1089 unsigned mulhwu_scale_factor(unsigned inscale
, unsigned outscale
)
1091 unsigned mlt
=0, tmp
, err
;
1092 /* No concern for performance, it's done once: use a stupid
1093 * but safe and compact method to find the multiplier.
1096 for (tmp
= 1U<<31; tmp
!= 0; tmp
>>= 1) {
1097 if (mulhwu(inscale
, mlt
|tmp
) < outscale
)
1101 /* We might still be off by 1 for the best approximation.
1102 * A side effect of this is that if outscale is too large
1103 * the returned value will be zero.
1104 * Many corner cases have been checked and seem to work,
1105 * some might have been forgotten in the test however.
1108 err
= inscale
* (mlt
+1);
1109 if (err
<= inscale
/2)
1115 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1118 void div128_by_32(u64 dividend_high
, u64 dividend_low
,
1119 unsigned divisor
, struct div_result
*dr
)
1121 unsigned long a
, b
, c
, d
;
1122 unsigned long w
, x
, y
, z
;
1125 a
= dividend_high
>> 32;
1126 b
= dividend_high
& 0xffffffff;
1127 c
= dividend_low
>> 32;
1128 d
= dividend_low
& 0xffffffff;
1131 ra
= ((u64
)(a
- (w
* divisor
)) << 32) + b
;
1133 rb
= ((u64
) do_div(ra
, divisor
) << 32) + c
;
1136 rc
= ((u64
) do_div(rb
, divisor
) << 32) + d
;
1139 do_div(rc
, divisor
);
1142 dr
->result_high
= ((u64
)w
<< 32) + x
;
1143 dr
->result_low
= ((u64
)y
<< 32) + z
;
1147 /* We don't need to calibrate delay, we use the CPU timebase for that */
1148 void calibrate_delay(void)
1150 /* Some generic code (such as spinlock debug) use loops_per_jiffy
1151 * as the number of __delay(1) in a jiffy, so make it so
1153 loops_per_jiffy
= tb_ticks_per_jiffy
;
1156 static int __init
rtc_init(void)
1158 struct platform_device
*pdev
;
1160 if (!ppc_md
.get_rtc_time
)
1163 pdev
= platform_device_register_simple("rtc-generic", -1, NULL
, 0);
1165 return PTR_ERR(pdev
);
1170 module_init(rtc_init
);