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>
56 #include <asm/processor.h>
57 #include <asm/nvram.h>
58 #include <asm/cache.h>
59 #include <asm/machdep.h>
60 #include <asm/uaccess.h>
64 #include <asm/div64.h>
66 #include <asm/vdso_datapage.h>
68 #include <asm/firmware.h>
70 #ifdef CONFIG_PPC_ISERIES
71 #include <asm/iseries/it_lp_queue.h>
72 #include <asm/iseries/hv_call_xm.h>
76 /* keep track of when we need to update the rtc */
77 time_t last_rtc_update
;
78 #ifdef CONFIG_PPC_ISERIES
79 unsigned long iSeries_recal_titan
= 0;
80 unsigned long iSeries_recal_tb
= 0;
81 static unsigned long first_settimeofday
= 1;
84 /* The decrementer counts down by 128 every 128ns on a 601. */
85 #define DECREMENTER_COUNT_601 (1000000000 / HZ)
87 #define XSEC_PER_SEC (1024*1024)
90 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
92 /* compute ((xsec << 12) * max) >> 32 */
93 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
96 unsigned long tb_ticks_per_jiffy
;
97 unsigned long tb_ticks_per_usec
= 100; /* sane default */
98 EXPORT_SYMBOL(tb_ticks_per_usec
);
99 unsigned long tb_ticks_per_sec
;
100 EXPORT_SYMBOL(tb_ticks_per_sec
); /* for cputime_t conversions */
104 #define TICKLEN_SCALE TICK_LENGTH_SHIFT
105 u64 last_tick_len
; /* units are ns / 2^TICKLEN_SCALE */
106 u64 ticklen_to_xs
; /* 0.64 fraction */
108 /* If last_tick_len corresponds to about 1/HZ seconds, then
109 last_tick_len << TICKLEN_SHIFT will be about 2^63. */
110 #define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ)
112 DEFINE_SPINLOCK(rtc_lock
);
113 EXPORT_SYMBOL_GPL(rtc_lock
);
116 unsigned tb_to_ns_shift
;
118 struct gettimeofday_struct do_gtod
;
120 extern struct timezone sys_tz
;
121 static long timezone_offset
;
123 unsigned long ppc_proc_freq
;
124 unsigned long ppc_tb_freq
;
126 static u64 tb_last_jiffy __cacheline_aligned_in_smp
;
127 static DEFINE_PER_CPU(u64
, last_jiffy
);
129 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
131 * Factors for converting from cputime_t (timebase ticks) to
132 * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds).
133 * These are all stored as 0.64 fixed-point binary fractions.
135 u64 __cputime_jiffies_factor
;
136 EXPORT_SYMBOL(__cputime_jiffies_factor
);
137 u64 __cputime_msec_factor
;
138 EXPORT_SYMBOL(__cputime_msec_factor
);
139 u64 __cputime_sec_factor
;
140 EXPORT_SYMBOL(__cputime_sec_factor
);
141 u64 __cputime_clockt_factor
;
142 EXPORT_SYMBOL(__cputime_clockt_factor
);
144 static void calc_cputime_factors(void)
146 struct div_result res
;
148 div128_by_32(HZ
, 0, tb_ticks_per_sec
, &res
);
149 __cputime_jiffies_factor
= res
.result_low
;
150 div128_by_32(1000, 0, tb_ticks_per_sec
, &res
);
151 __cputime_msec_factor
= res
.result_low
;
152 div128_by_32(1, 0, tb_ticks_per_sec
, &res
);
153 __cputime_sec_factor
= res
.result_low
;
154 div128_by_32(USER_HZ
, 0, tb_ticks_per_sec
, &res
);
155 __cputime_clockt_factor
= res
.result_low
;
159 * Read the PURR on systems that have it, otherwise the timebase.
161 static u64
read_purr(void)
163 if (cpu_has_feature(CPU_FTR_PURR
))
164 return mfspr(SPRN_PURR
);
169 * Account time for a transition between system, hard irq
172 void account_system_vtime(struct task_struct
*tsk
)
177 local_irq_save(flags
);
179 delta
= now
- get_paca()->startpurr
;
180 get_paca()->startpurr
= now
;
181 if (!in_interrupt()) {
182 delta
+= get_paca()->system_time
;
183 get_paca()->system_time
= 0;
185 account_system_time(tsk
, 0, delta
);
186 local_irq_restore(flags
);
190 * Transfer the user and system times accumulated in the paca
191 * by the exception entry and exit code to the generic process
192 * user and system time records.
193 * Must be called with interrupts disabled.
195 void account_process_vtime(struct task_struct
*tsk
)
199 utime
= get_paca()->user_time
;
200 get_paca()->user_time
= 0;
201 account_user_time(tsk
, utime
);
204 static void account_process_time(struct pt_regs
*regs
)
206 int cpu
= smp_processor_id();
208 account_process_vtime(current
);
210 if (rcu_pending(cpu
))
211 rcu_check_callbacks(cpu
, user_mode(regs
));
213 run_posix_cpu_timers(current
);
216 #ifdef CONFIG_PPC_SPLPAR
218 * Stuff for accounting stolen time.
220 struct cpu_purr_data
{
221 int initialized
; /* thread is running */
222 u64 tb0
; /* timebase at origin time */
223 u64 purr0
; /* PURR at origin time */
224 u64 tb
; /* last TB value read */
225 u64 purr
; /* last PURR value read */
226 u64 stolen
; /* stolen time so far */
230 static DEFINE_PER_CPU(struct cpu_purr_data
, cpu_purr_data
);
232 static void snapshot_tb_and_purr(void *data
)
234 struct cpu_purr_data
*p
= &__get_cpu_var(cpu_purr_data
);
237 p
->purr0
= mfspr(SPRN_PURR
);
245 * Called during boot when all cpus have come up.
247 void snapshot_timebases(void)
251 if (!cpu_has_feature(CPU_FTR_PURR
))
253 for_each_possible_cpu(cpu
)
254 spin_lock_init(&per_cpu(cpu_purr_data
, cpu
).lock
);
255 on_each_cpu(snapshot_tb_and_purr
, NULL
, 0, 1);
258 void calculate_steal_time(void)
262 struct cpu_purr_data
*p0
, *pme
, *phim
;
265 if (!cpu_has_feature(CPU_FTR_PURR
))
267 cpu
= smp_processor_id();
268 pme
= &per_cpu(cpu_purr_data
, cpu
);
269 if (!pme
->initialized
)
270 return; /* this can happen in early boot */
271 p0
= &per_cpu(cpu_purr_data
, cpu
& ~1);
272 phim
= &per_cpu(cpu_purr_data
, cpu
^ 1);
273 spin_lock(&p0
->lock
);
275 purr
= mfspr(SPRN_PURR
) - pme
->purr0
;
276 if (!phim
->initialized
|| !cpu_online(cpu
^ 1)) {
277 stolen
= (tb
- pme
->tb
) - (purr
- pme
->purr
);
282 stolen
= phim
->tb
- t0
- phim
->purr
- purr
- p0
->stolen
;
285 account_steal_time(current
, stolen
);
286 p0
->stolen
+= stolen
;
290 spin_unlock(&p0
->lock
);
294 * Must be called before the cpu is added to the online map when
295 * a cpu is being brought up at runtime.
297 static void snapshot_purr(void)
301 struct cpu_purr_data
*p0
, *pme
, *phim
;
304 if (!cpu_has_feature(CPU_FTR_PURR
))
306 cpu
= smp_processor_id();
307 pme
= &per_cpu(cpu_purr_data
, cpu
);
308 p0
= &per_cpu(cpu_purr_data
, cpu
& ~1);
309 phim
= &per_cpu(cpu_purr_data
, cpu
^ 1);
310 spin_lock_irqsave(&p0
->lock
, flags
);
311 pme
->tb
= pme
->tb0
= mftb();
312 purr
= mfspr(SPRN_PURR
);
313 if (!phim
->initialized
) {
317 /* set p->purr and p->purr0 for no change in p0->stolen */
318 pme
->purr
= phim
->tb
- phim
->tb0
- phim
->purr
- p0
->stolen
;
319 pme
->purr0
= purr
- pme
->purr
;
321 pme
->initialized
= 1;
322 spin_unlock_irqrestore(&p0
->lock
, flags
);
325 #endif /* CONFIG_PPC_SPLPAR */
327 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
328 #define calc_cputime_factors()
329 #define account_process_time(regs) update_process_times(user_mode(regs))
330 #define calculate_steal_time() do { } while (0)
333 #if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR))
334 #define snapshot_purr() do { } while (0)
338 * Called when a cpu comes up after the system has finished booting,
339 * i.e. as a result of a hotplug cpu action.
341 void snapshot_timebase(void)
343 __get_cpu_var(last_jiffy
) = get_tb();
347 void __delay(unsigned long loops
)
355 /* the RTCL register wraps at 1000000000 */
356 diff
= get_rtcl() - start
;
359 } while (diff
< loops
);
362 while (get_tbl() - start
< loops
)
367 EXPORT_SYMBOL(__delay
);
369 void udelay(unsigned long usecs
)
371 __delay(tb_ticks_per_usec
* usecs
);
373 EXPORT_SYMBOL(udelay
);
375 static __inline__
void timer_check_rtc(void)
378 * update the rtc when needed, this should be performed on the
379 * right fraction of a second. Half or full second ?
380 * Full second works on mk48t59 clocks, others need testing.
381 * Note that this update is basically only used through
382 * the adjtimex system calls. Setting the HW clock in
383 * any other way is a /dev/rtc and userland business.
384 * This is still wrong by -0.5/+1.5 jiffies because of the
385 * timer interrupt resolution and possible delay, but here we
386 * hit a quantization limit which can only be solved by higher
387 * resolution timers and decoupling time management from timer
388 * interrupts. This is also wrong on the clocks
389 * which require being written at the half second boundary.
390 * We should have an rtc call that only sets the minutes and
391 * seconds like on Intel to avoid problems with non UTC clocks.
393 if (ppc_md
.set_rtc_time
&& ntp_synced() &&
394 xtime
.tv_sec
- last_rtc_update
>= 659 &&
395 abs((xtime
.tv_nsec
/1000) - (1000000-1000000/HZ
)) < 500000/HZ
) {
397 to_tm(xtime
.tv_sec
+ 1 + timezone_offset
, &tm
);
400 if (ppc_md
.set_rtc_time(&tm
) == 0)
401 last_rtc_update
= xtime
.tv_sec
+ 1;
403 /* Try again one minute later */
404 last_rtc_update
+= 60;
409 * This version of gettimeofday has microsecond resolution.
411 static inline void __do_gettimeofday(struct timeval
*tv
)
413 unsigned long sec
, usec
;
415 struct gettimeofday_vars
*temp_varp
;
416 u64 temp_tb_to_xs
, temp_stamp_xsec
;
419 * These calculations are faster (gets rid of divides)
420 * if done in units of 1/2^20 rather than microseconds.
421 * The conversion to microseconds at the end is done
422 * without a divide (and in fact, without a multiply)
424 temp_varp
= do_gtod
.varp
;
426 /* Sampling the time base must be done after loading
427 * do_gtod.varp in order to avoid racing with update_gtod.
429 data_barrier(temp_varp
);
430 tb_ticks
= get_tb() - temp_varp
->tb_orig_stamp
;
431 temp_tb_to_xs
= temp_varp
->tb_to_xs
;
432 temp_stamp_xsec
= temp_varp
->stamp_xsec
;
433 xsec
= temp_stamp_xsec
+ mulhdu(tb_ticks
, temp_tb_to_xs
);
434 sec
= xsec
/ XSEC_PER_SEC
;
435 usec
= (unsigned long)xsec
& (XSEC_PER_SEC
- 1);
436 usec
= SCALE_XSEC(usec
, 1000000);
442 void do_gettimeofday(struct timeval
*tv
)
445 /* do this the old way */
446 unsigned long flags
, seq
;
447 unsigned int sec
, nsec
, usec
;
450 seq
= read_seqbegin_irqsave(&xtime_lock
, flags
);
452 nsec
= xtime
.tv_nsec
+ tb_ticks_since(tb_last_jiffy
);
453 } while (read_seqretry_irqrestore(&xtime_lock
, seq
, flags
));
455 while (usec
>= 1000000) {
463 __do_gettimeofday(tv
);
466 EXPORT_SYMBOL(do_gettimeofday
);
469 * There are two copies of tb_to_xs and stamp_xsec so that no
470 * lock is needed to access and use these values in
471 * do_gettimeofday. We alternate the copies and as long as a
472 * reasonable time elapses between changes, there will never
473 * be inconsistent values. ntpd has a minimum of one minute
476 static inline void update_gtod(u64 new_tb_stamp
, u64 new_stamp_xsec
,
480 struct gettimeofday_vars
*temp_varp
;
482 temp_idx
= (do_gtod
.var_idx
== 0);
483 temp_varp
= &do_gtod
.vars
[temp_idx
];
485 temp_varp
->tb_to_xs
= new_tb_to_xs
;
486 temp_varp
->tb_orig_stamp
= new_tb_stamp
;
487 temp_varp
->stamp_xsec
= new_stamp_xsec
;
489 do_gtod
.varp
= temp_varp
;
490 do_gtod
.var_idx
= temp_idx
;
493 * tb_update_count is used to allow the userspace gettimeofday code
494 * to assure itself that it sees a consistent view of the tb_to_xs and
495 * stamp_xsec variables. It reads the tb_update_count, then reads
496 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
497 * the two values of tb_update_count match and are even then the
498 * tb_to_xs and stamp_xsec values are consistent. If not, then it
499 * loops back and reads them again until this criteria is met.
500 * We expect the caller to have done the first increment of
501 * vdso_data->tb_update_count already.
503 vdso_data
->tb_orig_stamp
= new_tb_stamp
;
504 vdso_data
->stamp_xsec
= new_stamp_xsec
;
505 vdso_data
->tb_to_xs
= new_tb_to_xs
;
506 vdso_data
->wtom_clock_sec
= wall_to_monotonic
.tv_sec
;
507 vdso_data
->wtom_clock_nsec
= wall_to_monotonic
.tv_nsec
;
509 ++(vdso_data
->tb_update_count
);
513 * When the timebase - tb_orig_stamp gets too big, we do a manipulation
514 * between tb_orig_stamp and stamp_xsec. The goal here is to keep the
515 * difference tb - tb_orig_stamp small enough to always fit inside a
516 * 32 bits number. This is a requirement of our fast 32 bits userland
517 * implementation in the vdso. If we "miss" a call to this function
518 * (interrupt latency, CPU locked in a spinlock, ...) and we end up
519 * with a too big difference, then the vdso will fallback to calling
522 static __inline__
void timer_recalc_offset(u64 cur_tb
)
524 unsigned long offset
;
527 u64 tb
, xsec_old
, xsec_new
;
528 struct gettimeofday_vars
*varp
;
532 tlen
= current_tick_length();
533 offset
= cur_tb
- do_gtod
.varp
->tb_orig_stamp
;
534 if (tlen
== last_tick_len
&& offset
< 0x80000000u
)
536 if (tlen
!= last_tick_len
) {
537 t2x
= mulhdu(tlen
<< TICKLEN_SHIFT
, ticklen_to_xs
);
538 last_tick_len
= tlen
;
540 t2x
= do_gtod
.varp
->tb_to_xs
;
541 new_stamp_xsec
= (u64
) xtime
.tv_nsec
* XSEC_PER_SEC
;
542 do_div(new_stamp_xsec
, 1000000000);
543 new_stamp_xsec
+= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
545 ++vdso_data
->tb_update_count
;
549 * Make sure time doesn't go backwards for userspace gettimeofday.
553 xsec_old
= mulhdu(tb
- varp
->tb_orig_stamp
, varp
->tb_to_xs
)
555 xsec_new
= mulhdu(tb
- cur_tb
, t2x
) + new_stamp_xsec
;
556 if (xsec_new
< xsec_old
)
557 new_stamp_xsec
+= xsec_old
- xsec_new
;
559 update_gtod(cur_tb
, new_stamp_xsec
, t2x
);
563 unsigned long profile_pc(struct pt_regs
*regs
)
565 unsigned long pc
= instruction_pointer(regs
);
567 if (in_lock_functions(pc
))
572 EXPORT_SYMBOL(profile_pc
);
575 #ifdef CONFIG_PPC_ISERIES
578 * This function recalibrates the timebase based on the 49-bit time-of-day
579 * value in the Titan chip. The Titan is much more accurate than the value
580 * returned by the service processor for the timebase frequency.
583 static void iSeries_tb_recal(void)
585 struct div_result divres
;
586 unsigned long titan
, tb
;
588 titan
= HvCallXm_loadTod();
589 if ( iSeries_recal_titan
) {
590 unsigned long tb_ticks
= tb
- iSeries_recal_tb
;
591 unsigned long titan_usec
= (titan
- iSeries_recal_titan
) >> 12;
592 unsigned long new_tb_ticks_per_sec
= (tb_ticks
* USEC_PER_SEC
)/titan_usec
;
593 unsigned long new_tb_ticks_per_jiffy
= (new_tb_ticks_per_sec
+(HZ
/2))/HZ
;
594 long tick_diff
= new_tb_ticks_per_jiffy
- tb_ticks_per_jiffy
;
596 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */
597 new_tb_ticks_per_sec
= new_tb_ticks_per_jiffy
* HZ
;
599 if ( tick_diff
< 0 ) {
600 tick_diff
= -tick_diff
;
604 if ( tick_diff
< tb_ticks_per_jiffy
/25 ) {
605 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n",
606 new_tb_ticks_per_jiffy
, sign
, tick_diff
);
607 tb_ticks_per_jiffy
= new_tb_ticks_per_jiffy
;
608 tb_ticks_per_sec
= new_tb_ticks_per_sec
;
609 calc_cputime_factors();
610 div128_by_32( XSEC_PER_SEC
, 0, tb_ticks_per_sec
, &divres
);
611 do_gtod
.tb_ticks_per_sec
= tb_ticks_per_sec
;
612 tb_to_xs
= divres
.result_low
;
613 do_gtod
.varp
->tb_to_xs
= tb_to_xs
;
614 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
615 vdso_data
->tb_to_xs
= tb_to_xs
;
618 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n"
619 " new tb_ticks_per_jiffy = %lu\n"
620 " old tb_ticks_per_jiffy = %lu\n",
621 new_tb_ticks_per_jiffy
, tb_ticks_per_jiffy
);
625 iSeries_recal_titan
= titan
;
626 iSeries_recal_tb
= tb
;
631 * For iSeries shared processors, we have to let the hypervisor
632 * set the hardware decrementer. We set a virtual decrementer
633 * in the lppaca and call the hypervisor if the virtual
634 * decrementer is less than the current value in the hardware
635 * decrementer. (almost always the new decrementer value will
636 * be greater than the current hardware decementer so the hypervisor
637 * call will not be needed)
641 * timer_interrupt - gets called when the decrementer overflows,
642 * with interrupts disabled.
644 void timer_interrupt(struct pt_regs
* regs
)
647 int cpu
= smp_processor_id();
652 if (atomic_read(&ppc_n_lost_interrupts
) != 0)
658 profile_tick(CPU_PROFILING
, regs
);
659 calculate_steal_time();
661 #ifdef CONFIG_PPC_ISERIES
662 get_lppaca()->int_dword
.fields
.decr_int
= 0;
665 while ((ticks
= tb_ticks_since(per_cpu(last_jiffy
, cpu
)))
666 >= tb_ticks_per_jiffy
) {
667 /* Update last_jiffy */
668 per_cpu(last_jiffy
, cpu
) += tb_ticks_per_jiffy
;
669 /* Handle RTCL overflow on 601 */
670 if (__USE_RTC() && per_cpu(last_jiffy
, cpu
) >= 1000000000)
671 per_cpu(last_jiffy
, cpu
) -= 1000000000;
674 * We cannot disable the decrementer, so in the period
675 * between this cpu's being marked offline in cpu_online_map
676 * and calling stop-self, it is taking timer interrupts.
677 * Avoid calling into the scheduler rebalancing code if this
680 if (!cpu_is_offline(cpu
))
681 account_process_time(regs
);
684 * No need to check whether cpu is offline here; boot_cpuid
685 * should have been fixed up by now.
687 if (cpu
!= boot_cpuid
)
690 write_seqlock(&xtime_lock
);
691 tb_next_jiffy
= tb_last_jiffy
+ tb_ticks_per_jiffy
;
692 if (per_cpu(last_jiffy
, cpu
) >= tb_next_jiffy
) {
693 tb_last_jiffy
= tb_next_jiffy
;
695 timer_recalc_offset(tb_last_jiffy
);
698 write_sequnlock(&xtime_lock
);
701 next_dec
= tb_ticks_per_jiffy
- ticks
;
704 #ifdef CONFIG_PPC_ISERIES
705 if (hvlpevent_is_pending())
706 process_hvlpevents(regs
);
710 /* collect purr register values often, for accurate calculations */
711 if (firmware_has_feature(FW_FEATURE_SPLPAR
)) {
712 struct cpu_usage
*cu
= &__get_cpu_var(cpu_usage_array
);
713 cu
->current_tb
= mfspr(SPRN_PURR
);
720 void wakeup_decrementer(void)
725 * The timebase gets saved on sleep and restored on wakeup,
726 * so all we need to do is to reset the decrementer.
728 ticks
= tb_ticks_since(__get_cpu_var(last_jiffy
));
729 if (ticks
< tb_ticks_per_jiffy
)
730 ticks
= tb_ticks_per_jiffy
- ticks
;
737 void __init
smp_space_timers(unsigned int max_cpus
)
740 unsigned long half
= tb_ticks_per_jiffy
/ 2;
741 unsigned long offset
= tb_ticks_per_jiffy
/ max_cpus
;
742 u64 previous_tb
= per_cpu(last_jiffy
, boot_cpuid
);
744 /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */
745 previous_tb
-= tb_ticks_per_jiffy
;
747 * The stolen time calculation for POWER5 shared-processor LPAR
748 * systems works better if the two threads' timebase interrupts
749 * are staggered by half a jiffy with respect to each other.
751 for_each_possible_cpu(i
) {
754 if (i
== (boot_cpuid
^ 1))
755 per_cpu(last_jiffy
, i
) =
756 per_cpu(last_jiffy
, boot_cpuid
) - half
;
758 per_cpu(last_jiffy
, i
) =
759 per_cpu(last_jiffy
, i
^ 1) + half
;
761 previous_tb
+= offset
;
762 per_cpu(last_jiffy
, i
) = previous_tb
;
769 * Scheduler clock - returns current time in nanosec units.
771 * Note: mulhdu(a, b) (multiply high double unsigned) returns
772 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
773 * are 64-bit unsigned numbers.
775 unsigned long long sched_clock(void)
779 return mulhdu(get_tb(), tb_to_ns_scale
) << tb_to_ns_shift
;
782 int do_settimeofday(struct timespec
*tv
)
784 time_t wtm_sec
, new_sec
= tv
->tv_sec
;
785 long wtm_nsec
, new_nsec
= tv
->tv_nsec
;
788 unsigned long tb_delta
;
790 if ((unsigned long)tv
->tv_nsec
>= NSEC_PER_SEC
)
793 write_seqlock_irqsave(&xtime_lock
, flags
);
796 * Updating the RTC is not the job of this code. If the time is
797 * stepped under NTP, the RTC will be updated after STA_UNSYNC
798 * is cleared. Tools like clock/hwclock either copy the RTC
799 * to the system time, in which case there is no point in writing
800 * to the RTC again, or write to the RTC but then they don't call
801 * settimeofday to perform this operation.
803 #ifdef CONFIG_PPC_ISERIES
804 if (first_settimeofday
) {
806 first_settimeofday
= 0;
810 /* Make userspace gettimeofday spin until we're done. */
811 ++vdso_data
->tb_update_count
;
815 * Subtract off the number of nanoseconds since the
816 * beginning of the last tick.
818 tb_delta
= tb_ticks_since(tb_last_jiffy
);
819 tb_delta
= mulhdu(tb_delta
, do_gtod
.varp
->tb_to_xs
); /* in xsec */
820 new_nsec
-= SCALE_XSEC(tb_delta
, 1000000000);
822 wtm_sec
= wall_to_monotonic
.tv_sec
+ (xtime
.tv_sec
- new_sec
);
823 wtm_nsec
= wall_to_monotonic
.tv_nsec
+ (xtime
.tv_nsec
- new_nsec
);
825 set_normalized_timespec(&xtime
, new_sec
, new_nsec
);
826 set_normalized_timespec(&wall_to_monotonic
, wtm_sec
, wtm_nsec
);
828 /* In case of a large backwards jump in time with NTP, we want the
829 * clock to be updated as soon as the PLL is again in lock.
831 last_rtc_update
= new_sec
- 658;
835 new_xsec
= xtime
.tv_nsec
;
837 new_xsec
*= XSEC_PER_SEC
;
838 do_div(new_xsec
, NSEC_PER_SEC
);
840 new_xsec
+= (u64
)xtime
.tv_sec
* XSEC_PER_SEC
;
841 update_gtod(tb_last_jiffy
, new_xsec
, do_gtod
.varp
->tb_to_xs
);
843 vdso_data
->tz_minuteswest
= sys_tz
.tz_minuteswest
;
844 vdso_data
->tz_dsttime
= sys_tz
.tz_dsttime
;
846 write_sequnlock_irqrestore(&xtime_lock
, flags
);
851 EXPORT_SYMBOL(do_settimeofday
);
853 static int __init
get_freq(char *name
, int cells
, unsigned long *val
)
855 struct device_node
*cpu
;
856 const unsigned int *fp
;
859 /* The cpu node should have timebase and clock frequency properties */
860 cpu
= of_find_node_by_type(NULL
, "cpu");
863 fp
= get_property(cpu
, name
, NULL
);
866 *val
= of_read_ulong(fp
, cells
);
875 void __init
generic_calibrate_decr(void)
877 ppc_tb_freq
= DEFAULT_TB_FREQ
; /* hardcoded default */
879 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq
) &&
880 !get_freq("timebase-frequency", 1, &ppc_tb_freq
)) {
882 printk(KERN_ERR
"WARNING: Estimating decrementer frequency "
886 ppc_proc_freq
= DEFAULT_PROC_FREQ
; /* hardcoded default */
888 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq
) &&
889 !get_freq("clock-frequency", 1, &ppc_proc_freq
)) {
891 printk(KERN_ERR
"WARNING: Estimating processor frequency "
896 /* Set the time base to zero */
900 /* Clear any pending timer interrupts */
901 mtspr(SPRN_TSR
, TSR_ENW
| TSR_WIS
| TSR_DIS
| TSR_FIS
);
903 /* Enable decrementer interrupt */
904 mtspr(SPRN_TCR
, TCR_DIE
);
908 unsigned long get_boot_time(void)
912 if (ppc_md
.get_boot_time
)
913 return ppc_md
.get_boot_time();
914 if (!ppc_md
.get_rtc_time
)
916 ppc_md
.get_rtc_time(&tm
);
917 return mktime(tm
.tm_year
+1900, tm
.tm_mon
+1, tm
.tm_mday
,
918 tm
.tm_hour
, tm
.tm_min
, tm
.tm_sec
);
921 /* This function is only called on the boot processor */
922 void __init
time_init(void)
925 unsigned long tm
= 0;
926 struct div_result res
;
930 if (ppc_md
.time_init
!= NULL
)
931 timezone_offset
= ppc_md
.time_init();
934 /* 601 processor: dec counts down by 128 every 128ns */
935 ppc_tb_freq
= 1000000000;
936 tb_last_jiffy
= get_rtcl();
938 /* Normal PowerPC with timebase register */
939 ppc_md
.calibrate_decr();
940 printk(KERN_DEBUG
"time_init: decrementer frequency = %lu.%.6lu MHz\n",
941 ppc_tb_freq
/ 1000000, ppc_tb_freq
% 1000000);
942 printk(KERN_DEBUG
"time_init: processor frequency = %lu.%.6lu MHz\n",
943 ppc_proc_freq
/ 1000000, ppc_proc_freq
% 1000000);
944 tb_last_jiffy
= get_tb();
947 tb_ticks_per_jiffy
= ppc_tb_freq
/ HZ
;
948 tb_ticks_per_sec
= ppc_tb_freq
;
949 tb_ticks_per_usec
= ppc_tb_freq
/ 1000000;
950 tb_to_us
= mulhwu_scale_factor(ppc_tb_freq
, 1000000);
951 calc_cputime_factors();
954 * Calculate the length of each tick in ns. It will not be
955 * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ.
956 * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq,
959 x
= (u64
) NSEC_PER_SEC
* tb_ticks_per_jiffy
+ ppc_tb_freq
- 1;
960 do_div(x
, ppc_tb_freq
);
962 last_tick_len
= x
<< TICKLEN_SCALE
;
965 * Compute ticklen_to_xs, which is a factor which gets multiplied
966 * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value.
968 * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9)
969 * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT
970 * which turns out to be N = 51 - SHIFT_HZ.
971 * This gives the result as a 0.64 fixed-point fraction.
972 * That value is reduced by an offset amounting to 1 xsec per
973 * 2^31 timebase ticks to avoid problems with time going backwards
974 * by 1 xsec when we do timer_recalc_offset due to losing the
975 * fractional xsec. That offset is equal to ppc_tb_freq/2^51
976 * since there are 2^20 xsec in a second.
978 div128_by_32((1ULL << 51) - ppc_tb_freq
, 0,
979 tb_ticks_per_jiffy
<< SHIFT_HZ
, &res
);
980 div128_by_32(res
.result_high
, res
.result_low
, NSEC_PER_SEC
, &res
);
981 ticklen_to_xs
= res
.result_low
;
983 /* Compute tb_to_xs from tick_nsec */
984 tb_to_xs
= mulhdu(last_tick_len
<< TICKLEN_SHIFT
, ticklen_to_xs
);
987 * Compute scale factor for sched_clock.
988 * The calibrate_decr() function has set tb_ticks_per_sec,
989 * which is the timebase frequency.
990 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
991 * the 128-bit result as a 64.64 fixed-point number.
992 * We then shift that number right until it is less than 1.0,
993 * giving us the scale factor and shift count to use in
996 div128_by_32(1000000000, 0, tb_ticks_per_sec
, &res
);
997 scale
= res
.result_low
;
998 for (shift
= 0; res
.result_high
!= 0; ++shift
) {
999 scale
= (scale
>> 1) | (res
.result_high
<< 63);
1000 res
.result_high
>>= 1;
1002 tb_to_ns_scale
= scale
;
1003 tb_to_ns_shift
= shift
;
1005 tm
= get_boot_time();
1007 write_seqlock_irqsave(&xtime_lock
, flags
);
1009 /* If platform provided a timezone (pmac), we correct the time */
1010 if (timezone_offset
) {
1011 sys_tz
.tz_minuteswest
= -timezone_offset
/ 60;
1012 sys_tz
.tz_dsttime
= 0;
1013 tm
-= timezone_offset
;
1018 do_gtod
.varp
= &do_gtod
.vars
[0];
1019 do_gtod
.var_idx
= 0;
1020 do_gtod
.varp
->tb_orig_stamp
= tb_last_jiffy
;
1021 __get_cpu_var(last_jiffy
) = tb_last_jiffy
;
1022 do_gtod
.varp
->stamp_xsec
= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
1023 do_gtod
.tb_ticks_per_sec
= tb_ticks_per_sec
;
1024 do_gtod
.varp
->tb_to_xs
= tb_to_xs
;
1025 do_gtod
.tb_to_us
= tb_to_us
;
1027 vdso_data
->tb_orig_stamp
= tb_last_jiffy
;
1028 vdso_data
->tb_update_count
= 0;
1029 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
1030 vdso_data
->stamp_xsec
= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
1031 vdso_data
->tb_to_xs
= tb_to_xs
;
1035 last_rtc_update
= xtime
.tv_sec
;
1036 set_normalized_timespec(&wall_to_monotonic
,
1037 -xtime
.tv_sec
, -xtime
.tv_nsec
);
1038 write_sequnlock_irqrestore(&xtime_lock
, flags
);
1040 /* Not exact, but the timer interrupt takes care of this */
1041 set_dec(tb_ticks_per_jiffy
);
1046 #define STARTOFTIME 1970
1047 #define SECDAY 86400L
1048 #define SECYR (SECDAY * 365)
1049 #define leapyear(year) ((year) % 4 == 0 && \
1050 ((year) % 100 != 0 || (year) % 400 == 0))
1051 #define days_in_year(a) (leapyear(a) ? 366 : 365)
1052 #define days_in_month(a) (month_days[(a) - 1])
1054 static int month_days
[12] = {
1055 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
1059 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
1061 void GregorianDay(struct rtc_time
* tm
)
1066 int MonthOffset
[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
1068 lastYear
= tm
->tm_year
- 1;
1071 * Number of leap corrections to apply up to end of last year
1073 leapsToDate
= lastYear
/ 4 - lastYear
/ 100 + lastYear
/ 400;
1076 * This year is a leap year if it is divisible by 4 except when it is
1077 * divisible by 100 unless it is divisible by 400
1079 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
1081 day
= tm
->tm_mon
> 2 && leapyear(tm
->tm_year
);
1083 day
+= lastYear
*365 + leapsToDate
+ MonthOffset
[tm
->tm_mon
-1] +
1086 tm
->tm_wday
= day
% 7;
1089 void to_tm(int tim
, struct rtc_time
* tm
)
1092 register long hms
, day
;
1097 /* Hours, minutes, seconds are easy */
1098 tm
->tm_hour
= hms
/ 3600;
1099 tm
->tm_min
= (hms
% 3600) / 60;
1100 tm
->tm_sec
= (hms
% 3600) % 60;
1102 /* Number of years in days */
1103 for (i
= STARTOFTIME
; day
>= days_in_year(i
); i
++)
1104 day
-= days_in_year(i
);
1107 /* Number of months in days left */
1108 if (leapyear(tm
->tm_year
))
1109 days_in_month(FEBRUARY
) = 29;
1110 for (i
= 1; day
>= days_in_month(i
); i
++)
1111 day
-= days_in_month(i
);
1112 days_in_month(FEBRUARY
) = 28;
1115 /* Days are what is left over (+1) from all that. */
1116 tm
->tm_mday
= day
+ 1;
1119 * Determine the day of week
1124 /* Auxiliary function to compute scaling factors */
1125 /* Actually the choice of a timebase running at 1/4 the of the bus
1126 * frequency giving resolution of a few tens of nanoseconds is quite nice.
1127 * It makes this computation very precise (27-28 bits typically) which
1128 * is optimistic considering the stability of most processor clock
1129 * oscillators and the precision with which the timebase frequency
1130 * is measured but does not harm.
1132 unsigned mulhwu_scale_factor(unsigned inscale
, unsigned outscale
)
1134 unsigned mlt
=0, tmp
, err
;
1135 /* No concern for performance, it's done once: use a stupid
1136 * but safe and compact method to find the multiplier.
1139 for (tmp
= 1U<<31; tmp
!= 0; tmp
>>= 1) {
1140 if (mulhwu(inscale
, mlt
|tmp
) < outscale
)
1144 /* We might still be off by 1 for the best approximation.
1145 * A side effect of this is that if outscale is too large
1146 * the returned value will be zero.
1147 * Many corner cases have been checked and seem to work,
1148 * some might have been forgotten in the test however.
1151 err
= inscale
* (mlt
+1);
1152 if (err
<= inscale
/2)
1158 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1161 void div128_by_32(u64 dividend_high
, u64 dividend_low
,
1162 unsigned divisor
, struct div_result
*dr
)
1164 unsigned long a
, b
, c
, d
;
1165 unsigned long w
, x
, y
, z
;
1168 a
= dividend_high
>> 32;
1169 b
= dividend_high
& 0xffffffff;
1170 c
= dividend_low
>> 32;
1171 d
= dividend_low
& 0xffffffff;
1174 ra
= ((u64
)(a
- (w
* divisor
)) << 32) + b
;
1176 rb
= ((u64
) do_div(ra
, divisor
) << 32) + c
;
1179 rc
= ((u64
) do_div(rb
, divisor
) << 32) + d
;
1182 do_div(rc
, divisor
);
1185 dr
->result_high
= ((u64
)w
<< 32) + x
;
1186 dr
->result_low
= ((u64
)y
<< 32) + z
;