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/config.h>
36 #include <linux/errno.h>
37 #include <linux/module.h>
38 #include <linux/sched.h>
39 #include <linux/kernel.h>
40 #include <linux/param.h>
41 #include <linux/string.h>
43 #include <linux/interrupt.h>
44 #include <linux/timex.h>
45 #include <linux/kernel_stat.h>
46 #include <linux/time.h>
47 #include <linux/init.h>
48 #include <linux/profile.h>
49 #include <linux/cpu.h>
50 #include <linux/security.h>
51 #include <linux/percpu.h>
52 #include <linux/rtc.h>
55 #include <asm/processor.h>
56 #include <asm/nvram.h>
57 #include <asm/cache.h>
58 #include <asm/machdep.h>
59 #include <asm/uaccess.h>
63 #include <asm/div64.h>
65 #include <asm/systemcfg.h>
66 #include <asm/firmware.h>
68 #ifdef CONFIG_PPC_ISERIES
69 #include <asm/iseries/it_lp_queue.h>
70 #include <asm/iseries/hv_call_xm.h>
74 /* keep track of when we need to update the rtc */
75 time_t last_rtc_update
;
76 extern int piranha_simulator
;
77 #ifdef CONFIG_PPC_ISERIES
78 unsigned long iSeries_recal_titan
= 0;
79 unsigned long iSeries_recal_tb
= 0;
80 static unsigned long first_settimeofday
= 1;
83 /* The decrementer counts down by 128 every 128ns on a 601. */
84 #define DECREMENTER_COUNT_601 (1000000000 / HZ)
86 #define XSEC_PER_SEC (1024*1024)
89 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
91 /* compute ((xsec << 12) * max) >> 32 */
92 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
95 unsigned long tb_ticks_per_jiffy
;
96 unsigned long tb_ticks_per_usec
= 100; /* sane default */
97 EXPORT_SYMBOL(tb_ticks_per_usec
);
98 unsigned long tb_ticks_per_sec
;
101 unsigned long processor_freq
;
102 DEFINE_SPINLOCK(rtc_lock
);
103 EXPORT_SYMBOL_GPL(rtc_lock
);
106 unsigned tb_to_ns_shift
;
108 struct gettimeofday_struct do_gtod
;
110 extern unsigned long wall_jiffies
;
112 extern struct timezone sys_tz
;
113 static long timezone_offset
;
115 void ppc_adjtimex(void);
117 static unsigned adjusting_time
= 0;
119 unsigned long ppc_proc_freq
;
120 unsigned long ppc_tb_freq
;
122 #ifdef CONFIG_PPC32 /* XXX for now */
126 u64 tb_last_jiffy __cacheline_aligned_in_smp
;
127 unsigned long tb_last_stamp
;
130 * Note that on ppc32 this only stores the bottom 32 bits of
131 * the timebase value, but that's enough to tell when a jiffy
134 DEFINE_PER_CPU(unsigned long, last_jiffy
);
136 static __inline__
void timer_check_rtc(void)
139 * update the rtc when needed, this should be performed on the
140 * right fraction of a second. Half or full second ?
141 * Full second works on mk48t59 clocks, others need testing.
142 * Note that this update is basically only used through
143 * the adjtimex system calls. Setting the HW clock in
144 * any other way is a /dev/rtc and userland business.
145 * This is still wrong by -0.5/+1.5 jiffies because of the
146 * timer interrupt resolution and possible delay, but here we
147 * hit a quantization limit which can only be solved by higher
148 * resolution timers and decoupling time management from timer
149 * interrupts. This is also wrong on the clocks
150 * which require being written at the half second boundary.
151 * We should have an rtc call that only sets the minutes and
152 * seconds like on Intel to avoid problems with non UTC clocks.
154 if (ppc_md
.set_rtc_time
&& ntp_synced() &&
155 xtime
.tv_sec
- last_rtc_update
>= 659 &&
156 abs((xtime
.tv_nsec
/1000) - (1000000-1000000/HZ
)) < 500000/HZ
&&
157 jiffies
- wall_jiffies
== 1) {
159 to_tm(xtime
.tv_sec
+ 1 + timezone_offset
, &tm
);
162 if (ppc_md
.set_rtc_time(&tm
) == 0)
163 last_rtc_update
= xtime
.tv_sec
+ 1;
165 /* Try again one minute later */
166 last_rtc_update
+= 60;
171 * This version of gettimeofday has microsecond resolution.
173 static inline void __do_gettimeofday(struct timeval
*tv
, u64 tb_val
)
175 unsigned long sec
, usec
;
177 struct gettimeofday_vars
*temp_varp
;
178 u64 temp_tb_to_xs
, temp_stamp_xsec
;
181 * These calculations are faster (gets rid of divides)
182 * if done in units of 1/2^20 rather than microseconds.
183 * The conversion to microseconds at the end is done
184 * without a divide (and in fact, without a multiply)
186 temp_varp
= do_gtod
.varp
;
187 tb_ticks
= tb_val
- temp_varp
->tb_orig_stamp
;
188 temp_tb_to_xs
= temp_varp
->tb_to_xs
;
189 temp_stamp_xsec
= temp_varp
->stamp_xsec
;
190 xsec
= temp_stamp_xsec
+ mulhdu(tb_ticks
, temp_tb_to_xs
);
191 sec
= xsec
/ XSEC_PER_SEC
;
192 usec
= (unsigned long)xsec
& (XSEC_PER_SEC
- 1);
193 usec
= SCALE_XSEC(usec
, 1000000);
199 void do_gettimeofday(struct timeval
*tv
)
202 /* do this the old way */
203 unsigned long flags
, seq
;
204 unsigned int sec
, nsec
, usec
, lost
;
207 seq
= read_seqbegin_irqsave(&xtime_lock
, flags
);
209 nsec
= xtime
.tv_nsec
+ tb_ticks_since(tb_last_stamp
);
210 lost
= jiffies
- wall_jiffies
;
211 } while (read_seqretry_irqrestore(&xtime_lock
, seq
, flags
));
212 usec
= nsec
/ 1000 + lost
* (1000000 / HZ
);
213 while (usec
>= 1000000) {
221 __do_gettimeofday(tv
, get_tb());
224 EXPORT_SYMBOL(do_gettimeofday
);
226 /* Synchronize xtime with do_gettimeofday */
228 static inline void timer_sync_xtime(unsigned long cur_tb
)
231 /* why do we do this? */
232 struct timeval my_tv
;
234 __do_gettimeofday(&my_tv
, cur_tb
);
236 if (xtime
.tv_sec
<= my_tv
.tv_sec
) {
237 xtime
.tv_sec
= my_tv
.tv_sec
;
238 xtime
.tv_nsec
= my_tv
.tv_usec
* 1000;
244 * There are two copies of tb_to_xs and stamp_xsec so that no
245 * lock is needed to access and use these values in
246 * do_gettimeofday. We alternate the copies and as long as a
247 * reasonable time elapses between changes, there will never
248 * be inconsistent values. ntpd has a minimum of one minute
251 static inline void update_gtod(u64 new_tb_stamp
, u64 new_stamp_xsec
,
255 struct gettimeofday_vars
*temp_varp
;
257 temp_idx
= (do_gtod
.var_idx
== 0);
258 temp_varp
= &do_gtod
.vars
[temp_idx
];
260 temp_varp
->tb_to_xs
= new_tb_to_xs
;
261 temp_varp
->tb_orig_stamp
= new_tb_stamp
;
262 temp_varp
->stamp_xsec
= new_stamp_xsec
;
264 do_gtod
.varp
= temp_varp
;
265 do_gtod
.var_idx
= temp_idx
;
269 * tb_update_count is used to allow the userspace gettimeofday code
270 * to assure itself that it sees a consistent view of the tb_to_xs and
271 * stamp_xsec variables. It reads the tb_update_count, then reads
272 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
273 * the two values of tb_update_count match and are even then the
274 * tb_to_xs and stamp_xsec values are consistent. If not, then it
275 * loops back and reads them again until this criteria is met.
277 ++(systemcfg
->tb_update_count
);
279 systemcfg
->tb_orig_stamp
= new_tb_stamp
;
280 systemcfg
->stamp_xsec
= new_stamp_xsec
;
281 systemcfg
->tb_to_xs
= new_tb_to_xs
;
283 ++(systemcfg
->tb_update_count
);
288 * When the timebase - tb_orig_stamp gets too big, we do a manipulation
289 * between tb_orig_stamp and stamp_xsec. The goal here is to keep the
290 * difference tb - tb_orig_stamp small enough to always fit inside a
291 * 32 bits number. This is a requirement of our fast 32 bits userland
292 * implementation in the vdso. If we "miss" a call to this function
293 * (interrupt latency, CPU locked in a spinlock, ...) and we end up
294 * with a too big difference, then the vdso will fallback to calling
297 static __inline__
void timer_recalc_offset(u64 cur_tb
)
299 unsigned long offset
;
304 offset
= cur_tb
- do_gtod
.varp
->tb_orig_stamp
;
305 if ((offset
& 0x80000000u
) == 0)
307 new_stamp_xsec
= do_gtod
.varp
->stamp_xsec
308 + mulhdu(offset
, do_gtod
.varp
->tb_to_xs
);
309 update_gtod(cur_tb
, new_stamp_xsec
, do_gtod
.varp
->tb_to_xs
);
313 unsigned long profile_pc(struct pt_regs
*regs
)
315 unsigned long pc
= instruction_pointer(regs
);
317 if (in_lock_functions(pc
))
322 EXPORT_SYMBOL(profile_pc
);
325 #ifdef CONFIG_PPC_ISERIES
328 * This function recalibrates the timebase based on the 49-bit time-of-day
329 * value in the Titan chip. The Titan is much more accurate than the value
330 * returned by the service processor for the timebase frequency.
333 static void iSeries_tb_recal(void)
335 struct div_result divres
;
336 unsigned long titan
, tb
;
338 titan
= HvCallXm_loadTod();
339 if ( iSeries_recal_titan
) {
340 unsigned long tb_ticks
= tb
- iSeries_recal_tb
;
341 unsigned long titan_usec
= (titan
- iSeries_recal_titan
) >> 12;
342 unsigned long new_tb_ticks_per_sec
= (tb_ticks
* USEC_PER_SEC
)/titan_usec
;
343 unsigned long new_tb_ticks_per_jiffy
= (new_tb_ticks_per_sec
+(HZ
/2))/HZ
;
344 long tick_diff
= new_tb_ticks_per_jiffy
- tb_ticks_per_jiffy
;
346 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */
347 new_tb_ticks_per_sec
= new_tb_ticks_per_jiffy
* HZ
;
349 if ( tick_diff
< 0 ) {
350 tick_diff
= -tick_diff
;
354 if ( tick_diff
< tb_ticks_per_jiffy
/25 ) {
355 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n",
356 new_tb_ticks_per_jiffy
, sign
, tick_diff
);
357 tb_ticks_per_jiffy
= new_tb_ticks_per_jiffy
;
358 tb_ticks_per_sec
= new_tb_ticks_per_sec
;
359 div128_by_32( XSEC_PER_SEC
, 0, tb_ticks_per_sec
, &divres
);
360 do_gtod
.tb_ticks_per_sec
= tb_ticks_per_sec
;
361 tb_to_xs
= divres
.result_low
;
362 do_gtod
.varp
->tb_to_xs
= tb_to_xs
;
363 systemcfg
->tb_ticks_per_sec
= tb_ticks_per_sec
;
364 systemcfg
->tb_to_xs
= tb_to_xs
;
367 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n"
368 " new tb_ticks_per_jiffy = %lu\n"
369 " old tb_ticks_per_jiffy = %lu\n",
370 new_tb_ticks_per_jiffy
, tb_ticks_per_jiffy
);
374 iSeries_recal_titan
= titan
;
375 iSeries_recal_tb
= tb
;
380 * For iSeries shared processors, we have to let the hypervisor
381 * set the hardware decrementer. We set a virtual decrementer
382 * in the lppaca and call the hypervisor if the virtual
383 * decrementer is less than the current value in the hardware
384 * decrementer. (almost always the new decrementer value will
385 * be greater than the current hardware decementer so the hypervisor
386 * call will not be needed)
390 * timer_interrupt - gets called when the decrementer overflows,
391 * with interrupts disabled.
393 void timer_interrupt(struct pt_regs
* regs
)
396 int cpu
= smp_processor_id();
400 if (atomic_read(&ppc_n_lost_interrupts
) != 0)
406 profile_tick(CPU_PROFILING
, regs
);
408 #ifdef CONFIG_PPC_ISERIES
409 get_paca()->lppaca
.int_dword
.fields
.decr_int
= 0;
412 while ((ticks
= tb_ticks_since(per_cpu(last_jiffy
, cpu
)))
413 >= tb_ticks_per_jiffy
) {
414 /* Update last_jiffy */
415 per_cpu(last_jiffy
, cpu
) += tb_ticks_per_jiffy
;
416 /* Handle RTCL overflow on 601 */
417 if (__USE_RTC() && per_cpu(last_jiffy
, cpu
) >= 1000000000)
418 per_cpu(last_jiffy
, cpu
) -= 1000000000;
421 * We cannot disable the decrementer, so in the period
422 * between this cpu's being marked offline in cpu_online_map
423 * and calling stop-self, it is taking timer interrupts.
424 * Avoid calling into the scheduler rebalancing code if this
427 if (!cpu_is_offline(cpu
))
428 update_process_times(user_mode(regs
));
431 * No need to check whether cpu is offline here; boot_cpuid
432 * should have been fixed up by now.
434 if (cpu
!= boot_cpuid
)
437 write_seqlock(&xtime_lock
);
438 tb_last_jiffy
+= tb_ticks_per_jiffy
;
439 tb_last_stamp
= per_cpu(last_jiffy
, cpu
);
440 timer_recalc_offset(tb_last_jiffy
);
442 timer_sync_xtime(tb_last_jiffy
);
444 write_sequnlock(&xtime_lock
);
445 if (adjusting_time
&& (time_adjust
== 0))
449 next_dec
= tb_ticks_per_jiffy
- ticks
;
452 #ifdef CONFIG_PPC_ISERIES
453 if (hvlpevent_is_pending())
454 process_hvlpevents(regs
);
458 /* collect purr register values often, for accurate calculations */
459 if (firmware_has_feature(FW_FEATURE_SPLPAR
)) {
460 struct cpu_usage
*cu
= &__get_cpu_var(cpu_usage_array
);
461 cu
->current_tb
= mfspr(SPRN_PURR
);
468 void wakeup_decrementer(void)
472 set_dec(tb_ticks_per_jiffy
);
474 * We don't expect this to be called on a machine with a 601,
475 * so using get_tbl is fine.
477 tb_last_stamp
= tb_last_jiffy
= get_tb();
479 per_cpu(last_jiffy
, i
) = tb_last_stamp
;
483 void __init
smp_space_timers(unsigned int max_cpus
)
486 unsigned long offset
= tb_ticks_per_jiffy
/ max_cpus
;
487 unsigned long previous_tb
= per_cpu(last_jiffy
, boot_cpuid
);
490 if (i
!= boot_cpuid
) {
491 previous_tb
+= offset
;
492 per_cpu(last_jiffy
, i
) = previous_tb
;
499 * Scheduler clock - returns current time in nanosec units.
501 * Note: mulhdu(a, b) (multiply high double unsigned) returns
502 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
503 * are 64-bit unsigned numbers.
505 unsigned long long sched_clock(void)
509 return mulhdu(get_tb(), tb_to_ns_scale
) << tb_to_ns_shift
;
512 int do_settimeofday(struct timespec
*tv
)
514 time_t wtm_sec
, new_sec
= tv
->tv_sec
;
515 long wtm_nsec
, new_nsec
= tv
->tv_nsec
;
518 u64 new_xsec
, tb_delta_xs
;
520 if ((unsigned long)tv
->tv_nsec
>= NSEC_PER_SEC
)
523 write_seqlock_irqsave(&xtime_lock
, flags
);
526 * Updating the RTC is not the job of this code. If the time is
527 * stepped under NTP, the RTC will be updated after STA_UNSYNC
528 * is cleared. Tools like clock/hwclock either copy the RTC
529 * to the system time, in which case there is no point in writing
530 * to the RTC again, or write to the RTC but then they don't call
531 * settimeofday to perform this operation.
533 #ifdef CONFIG_PPC_ISERIES
534 if (first_settimeofday
) {
536 first_settimeofday
= 0;
539 tb_delta
= tb_ticks_since(tb_last_stamp
);
540 tb_delta
+= (jiffies
- wall_jiffies
) * tb_ticks_per_jiffy
;
541 tb_delta_xs
= mulhdu(tb_delta
, do_gtod
.varp
->tb_to_xs
);
543 wtm_sec
= wall_to_monotonic
.tv_sec
+ (xtime
.tv_sec
- new_sec
);
544 wtm_nsec
= wall_to_monotonic
.tv_nsec
+ (xtime
.tv_nsec
- new_nsec
);
546 set_normalized_timespec(&xtime
, new_sec
, new_nsec
);
547 set_normalized_timespec(&wall_to_monotonic
, wtm_sec
, wtm_nsec
);
549 /* In case of a large backwards jump in time with NTP, we want the
550 * clock to be updated as soon as the PLL is again in lock.
552 last_rtc_update
= new_sec
- 658;
558 new_xsec
= (u64
)new_nsec
* XSEC_PER_SEC
;
559 do_div(new_xsec
, NSEC_PER_SEC
);
561 new_xsec
+= (u64
)new_sec
* XSEC_PER_SEC
- tb_delta_xs
;
562 update_gtod(tb_last_jiffy
, new_xsec
, do_gtod
.varp
->tb_to_xs
);
565 systemcfg
->tz_minuteswest
= sys_tz
.tz_minuteswest
;
566 systemcfg
->tz_dsttime
= sys_tz
.tz_dsttime
;
569 write_sequnlock_irqrestore(&xtime_lock
, flags
);
574 EXPORT_SYMBOL(do_settimeofday
);
576 void __init
generic_calibrate_decr(void)
578 struct device_node
*cpu
;
583 * The cpu node should have a timebase-frequency property
584 * to tell us the rate at which the decrementer counts.
586 cpu
= of_find_node_by_type(NULL
, "cpu");
588 ppc_tb_freq
= DEFAULT_TB_FREQ
; /* hardcoded default */
591 fp
= (unsigned int *)get_property(cpu
, "timebase-frequency",
599 printk(KERN_ERR
"WARNING: Estimating decrementer frequency "
602 ppc_proc_freq
= DEFAULT_PROC_FREQ
;
605 fp
= (unsigned int *)get_property(cpu
, "clock-frequency",
613 /* Set the time base to zero */
617 /* Clear any pending timer interrupts */
618 mtspr(SPRN_TSR
, TSR_ENW
| TSR_WIS
| TSR_DIS
| TSR_FIS
);
620 /* Enable decrementer interrupt */
621 mtspr(SPRN_TCR
, TCR_DIE
);
624 printk(KERN_ERR
"WARNING: Estimating processor frequency "
630 unsigned long get_boot_time(void)
634 if (ppc_md
.get_boot_time
)
635 return ppc_md
.get_boot_time();
636 if (!ppc_md
.get_rtc_time
)
638 ppc_md
.get_rtc_time(&tm
);
639 return mktime(tm
.tm_year
+1900, tm
.tm_mon
+1, tm
.tm_mday
,
640 tm
.tm_hour
, tm
.tm_min
, tm
.tm_sec
);
643 /* This function is only called on the boot processor */
644 void __init
time_init(void)
647 unsigned long tm
= 0;
648 struct div_result res
;
652 if (ppc_md
.time_init
!= NULL
)
653 timezone_offset
= ppc_md
.time_init();
656 /* 601 processor: dec counts down by 128 every 128ns */
657 ppc_tb_freq
= 1000000000;
658 tb_last_stamp
= get_rtcl();
659 tb_last_jiffy
= tb_last_stamp
;
661 /* Normal PowerPC with timebase register */
662 ppc_md
.calibrate_decr();
663 printk(KERN_INFO
"time_init: decrementer frequency = %lu.%.6lu MHz\n",
664 ppc_tb_freq
/ 1000000, ppc_tb_freq
% 1000000);
665 printk(KERN_INFO
"time_init: processor frequency = %lu.%.6lu MHz\n",
666 ppc_proc_freq
/ 1000000, ppc_proc_freq
% 1000000);
667 tb_last_stamp
= tb_last_jiffy
= get_tb();
670 tb_ticks_per_jiffy
= ppc_tb_freq
/ HZ
;
671 tb_ticks_per_sec
= tb_ticks_per_jiffy
* HZ
;
672 tb_ticks_per_usec
= ppc_tb_freq
/ 1000000;
673 tb_to_us
= mulhwu_scale_factor(ppc_tb_freq
, 1000000);
674 div128_by_32(1024*1024, 0, tb_ticks_per_sec
, &res
);
675 tb_to_xs
= res
.result_low
;
678 get_paca()->default_decr
= tb_ticks_per_jiffy
;
682 * Compute scale factor for sched_clock.
683 * The calibrate_decr() function has set tb_ticks_per_sec,
684 * which is the timebase frequency.
685 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
686 * the 128-bit result as a 64.64 fixed-point number.
687 * We then shift that number right until it is less than 1.0,
688 * giving us the scale factor and shift count to use in
691 div128_by_32(1000000000, 0, tb_ticks_per_sec
, &res
);
692 scale
= res
.result_low
;
693 for (shift
= 0; res
.result_high
!= 0; ++shift
) {
694 scale
= (scale
>> 1) | (res
.result_high
<< 63);
695 res
.result_high
>>= 1;
697 tb_to_ns_scale
= scale
;
698 tb_to_ns_shift
= shift
;
700 #ifdef CONFIG_PPC_ISERIES
701 if (!piranha_simulator
)
703 tm
= get_boot_time();
705 write_seqlock_irqsave(&xtime_lock
, flags
);
708 do_gtod
.varp
= &do_gtod
.vars
[0];
710 do_gtod
.varp
->tb_orig_stamp
= tb_last_jiffy
;
711 __get_cpu_var(last_jiffy
) = tb_last_stamp
;
712 do_gtod
.varp
->stamp_xsec
= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
713 do_gtod
.tb_ticks_per_sec
= tb_ticks_per_sec
;
714 do_gtod
.varp
->tb_to_xs
= tb_to_xs
;
715 do_gtod
.tb_to_us
= tb_to_us
;
717 systemcfg
->tb_orig_stamp
= tb_last_jiffy
;
718 systemcfg
->tb_update_count
= 0;
719 systemcfg
->tb_ticks_per_sec
= tb_ticks_per_sec
;
720 systemcfg
->stamp_xsec
= xtime
.tv_sec
* XSEC_PER_SEC
;
721 systemcfg
->tb_to_xs
= tb_to_xs
;
726 /* If platform provided a timezone (pmac), we correct the time */
727 if (timezone_offset
) {
728 sys_tz
.tz_minuteswest
= -timezone_offset
/ 60;
729 sys_tz
.tz_dsttime
= 0;
730 xtime
.tv_sec
-= timezone_offset
;
733 last_rtc_update
= xtime
.tv_sec
;
734 set_normalized_timespec(&wall_to_monotonic
,
735 -xtime
.tv_sec
, -xtime
.tv_nsec
);
736 write_sequnlock_irqrestore(&xtime_lock
, flags
);
738 /* Not exact, but the timer interrupt takes care of this */
739 set_dec(tb_ticks_per_jiffy
);
743 * After adjtimex is called, adjust the conversion of tb ticks
744 * to microseconds to keep do_gettimeofday synchronized
747 * Use the time_adjust, time_freq and time_offset computed by adjtimex to
748 * adjust the frequency.
751 /* #define DEBUG_PPC_ADJTIMEX 1 */
753 void ppc_adjtimex(void)
756 unsigned long den
, new_tb_ticks_per_sec
, tb_ticks
, old_xsec
,
757 new_tb_to_xs
, new_xsec
, new_stamp_xsec
;
758 unsigned long tb_ticks_per_sec_delta
;
759 long delta_freq
, ltemp
;
760 struct div_result divres
;
762 long singleshot_ppm
= 0;
765 * Compute parts per million frequency adjustment to
766 * accomplish the time adjustment implied by time_offset to be
767 * applied over the elapsed time indicated by time_constant.
768 * Use SHIFT_USEC to get it into the same units as
771 if ( time_offset
< 0 ) {
772 ltemp
= -time_offset
;
773 ltemp
<<= SHIFT_USEC
- SHIFT_UPDATE
;
774 ltemp
>>= SHIFT_KG
+ time_constant
;
778 ltemp
<<= SHIFT_USEC
- SHIFT_UPDATE
;
779 ltemp
>>= SHIFT_KG
+ time_constant
;
782 /* If there is a single shot time adjustment in progress */
784 #ifdef DEBUG_PPC_ADJTIMEX
785 printk("ppc_adjtimex: ");
786 if ( adjusting_time
== 0 )
788 printk("single shot time_adjust = %ld\n", time_adjust
);
794 * Compute parts per million frequency adjustment
795 * to match time_adjust
797 singleshot_ppm
= tickadj
* HZ
;
799 * The adjustment should be tickadj*HZ to match the code in
800 * linux/kernel/timer.c, but experiments show that this is too
801 * large. 3/4 of tickadj*HZ seems about right
803 singleshot_ppm
-= singleshot_ppm
/ 4;
804 /* Use SHIFT_USEC to get it into the same units as time_freq */
805 singleshot_ppm
<<= SHIFT_USEC
;
806 if ( time_adjust
< 0 )
807 singleshot_ppm
= -singleshot_ppm
;
810 #ifdef DEBUG_PPC_ADJTIMEX
811 if ( adjusting_time
)
812 printk("ppc_adjtimex: ending single shot time_adjust\n");
817 /* Add up all of the frequency adjustments */
818 delta_freq
= time_freq
+ ltemp
+ singleshot_ppm
;
821 * Compute a new value for tb_ticks_per_sec based on
822 * the frequency adjustment
824 den
= 1000000 * (1 << (SHIFT_USEC
- 8));
825 if ( delta_freq
< 0 ) {
826 tb_ticks_per_sec_delta
= ( tb_ticks_per_sec
* ( (-delta_freq
) >> (SHIFT_USEC
- 8))) / den
;
827 new_tb_ticks_per_sec
= tb_ticks_per_sec
+ tb_ticks_per_sec_delta
;
830 tb_ticks_per_sec_delta
= ( tb_ticks_per_sec
* ( delta_freq
>> (SHIFT_USEC
- 8))) / den
;
831 new_tb_ticks_per_sec
= tb_ticks_per_sec
- tb_ticks_per_sec_delta
;
834 #ifdef DEBUG_PPC_ADJTIMEX
835 printk("ppc_adjtimex: ltemp = %ld, time_freq = %ld, singleshot_ppm = %ld\n", ltemp
, time_freq
, singleshot_ppm
);
836 printk("ppc_adjtimex: tb_ticks_per_sec - base = %ld new = %ld\n", tb_ticks_per_sec
, new_tb_ticks_per_sec
);
840 * Compute a new value of tb_to_xs (used to convert tb to
841 * microseconds) and a new value of stamp_xsec which is the
842 * time (in 1/2^20 second units) corresponding to
843 * tb_orig_stamp. This new value of stamp_xsec compensates
844 * for the change in frequency (implied by the new tb_to_xs)
845 * which guarantees that the current time remains the same.
847 write_seqlock_irqsave( &xtime_lock
, flags
);
848 tb_ticks
= get_tb() - do_gtod
.varp
->tb_orig_stamp
;
849 div128_by_32(1024*1024, 0, new_tb_ticks_per_sec
, &divres
);
850 new_tb_to_xs
= divres
.result_low
;
851 new_xsec
= mulhdu(tb_ticks
, new_tb_to_xs
);
853 old_xsec
= mulhdu(tb_ticks
, do_gtod
.varp
->tb_to_xs
);
854 new_stamp_xsec
= do_gtod
.varp
->stamp_xsec
+ old_xsec
- new_xsec
;
856 update_gtod(do_gtod
.varp
->tb_orig_stamp
, new_stamp_xsec
, new_tb_to_xs
);
858 write_sequnlock_irqrestore( &xtime_lock
, flags
);
859 #endif /* CONFIG_PPC64 */
864 #define STARTOFTIME 1970
865 #define SECDAY 86400L
866 #define SECYR (SECDAY * 365)
867 #define leapyear(year) ((year) % 4 == 0 && \
868 ((year) % 100 != 0 || (year) % 400 == 0))
869 #define days_in_year(a) (leapyear(a) ? 366 : 365)
870 #define days_in_month(a) (month_days[(a) - 1])
872 static int month_days
[12] = {
873 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
877 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
879 void GregorianDay(struct rtc_time
* tm
)
884 int MonthOffset
[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
886 lastYear
= tm
->tm_year
- 1;
889 * Number of leap corrections to apply up to end of last year
891 leapsToDate
= lastYear
/ 4 - lastYear
/ 100 + lastYear
/ 400;
894 * This year is a leap year if it is divisible by 4 except when it is
895 * divisible by 100 unless it is divisible by 400
897 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
899 day
= tm
->tm_mon
> 2 && leapyear(tm
->tm_year
);
901 day
+= lastYear
*365 + leapsToDate
+ MonthOffset
[tm
->tm_mon
-1] +
904 tm
->tm_wday
= day
% 7;
907 void to_tm(int tim
, struct rtc_time
* tm
)
910 register long hms
, day
;
915 /* Hours, minutes, seconds are easy */
916 tm
->tm_hour
= hms
/ 3600;
917 tm
->tm_min
= (hms
% 3600) / 60;
918 tm
->tm_sec
= (hms
% 3600) % 60;
920 /* Number of years in days */
921 for (i
= STARTOFTIME
; day
>= days_in_year(i
); i
++)
922 day
-= days_in_year(i
);
925 /* Number of months in days left */
926 if (leapyear(tm
->tm_year
))
927 days_in_month(FEBRUARY
) = 29;
928 for (i
= 1; day
>= days_in_month(i
); i
++)
929 day
-= days_in_month(i
);
930 days_in_month(FEBRUARY
) = 28;
933 /* Days are what is left over (+1) from all that. */
934 tm
->tm_mday
= day
+ 1;
937 * Determine the day of week
942 /* Auxiliary function to compute scaling factors */
943 /* Actually the choice of a timebase running at 1/4 the of the bus
944 * frequency giving resolution of a few tens of nanoseconds is quite nice.
945 * It makes this computation very precise (27-28 bits typically) which
946 * is optimistic considering the stability of most processor clock
947 * oscillators and the precision with which the timebase frequency
948 * is measured but does not harm.
950 unsigned mulhwu_scale_factor(unsigned inscale
, unsigned outscale
)
952 unsigned mlt
=0, tmp
, err
;
953 /* No concern for performance, it's done once: use a stupid
954 * but safe and compact method to find the multiplier.
957 for (tmp
= 1U<<31; tmp
!= 0; tmp
>>= 1) {
958 if (mulhwu(inscale
, mlt
|tmp
) < outscale
)
962 /* We might still be off by 1 for the best approximation.
963 * A side effect of this is that if outscale is too large
964 * the returned value will be zero.
965 * Many corner cases have been checked and seem to work,
966 * some might have been forgotten in the test however.
969 err
= inscale
* (mlt
+1);
970 if (err
<= inscale
/2)
976 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
979 void div128_by_32(u64 dividend_high
, u64 dividend_low
,
980 unsigned divisor
, struct div_result
*dr
)
982 unsigned long a
, b
, c
, d
;
983 unsigned long w
, x
, y
, z
;
986 a
= dividend_high
>> 32;
987 b
= dividend_high
& 0xffffffff;
988 c
= dividend_low
>> 32;
989 d
= dividend_low
& 0xffffffff;
992 ra
= ((u64
)(a
- (w
* divisor
)) << 32) + b
;
994 rb
= ((u64
) do_div(ra
, divisor
) << 32) + c
;
997 rc
= ((u64
) do_div(rb
, divisor
) << 32) + d
;
1000 do_div(rc
, divisor
);
1003 dr
->result_high
= ((u64
)w
<< 32) + x
;
1004 dr
->result_low
= ((u64
)y
<< 32) + z
;