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>
56 #include <linux/perf_counter.h>
59 #include <asm/processor.h>
60 #include <asm/nvram.h>
61 #include <asm/cache.h>
62 #include <asm/machdep.h>
63 #include <asm/uaccess.h>
67 #include <asm/div64.h>
69 #include <asm/vdso_datapage.h>
70 #include <asm/firmware.h>
71 #include <asm/cputime.h>
72 #ifdef CONFIG_PPC_ISERIES
73 #include <asm/iseries/it_lp_queue.h>
74 #include <asm/iseries/hv_call_xm.h>
77 /* powerpc clocksource/clockevent code */
79 #include <linux/clockchips.h>
80 #include <linux/clocksource.h>
82 static cycle_t
rtc_read(struct clocksource
*);
83 static struct clocksource clocksource_rtc
= {
86 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
87 .mask
= CLOCKSOURCE_MASK(64),
89 .mult
= 0, /* To be filled in */
93 static cycle_t
timebase_read(struct clocksource
*);
94 static struct clocksource clocksource_timebase
= {
97 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
98 .mask
= CLOCKSOURCE_MASK(64),
100 .mult
= 0, /* To be filled in */
101 .read
= timebase_read
,
104 #define DECREMENTER_MAX 0x7fffffff
106 static int decrementer_set_next_event(unsigned long evt
,
107 struct clock_event_device
*dev
);
108 static void decrementer_set_mode(enum clock_event_mode mode
,
109 struct clock_event_device
*dev
);
111 static struct clock_event_device decrementer_clockevent
= {
112 .name
= "decrementer",
114 .shift
= 0, /* To be filled in */
115 .mult
= 0, /* To be filled in */
117 .set_next_event
= decrementer_set_next_event
,
118 .set_mode
= decrementer_set_mode
,
119 .features
= CLOCK_EVT_FEAT_ONESHOT
,
122 struct decrementer_clock
{
123 struct clock_event_device event
;
127 static DEFINE_PER_CPU(struct decrementer_clock
, decrementers
);
129 #ifdef CONFIG_PPC_ISERIES
130 static unsigned long __initdata iSeries_recal_titan
;
131 static signed long __initdata iSeries_recal_tb
;
133 /* Forward declaration is only needed for iSereis compiles */
134 static void __init
clocksource_init(void);
137 #define XSEC_PER_SEC (1024*1024)
140 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
142 /* compute ((xsec << 12) * max) >> 32 */
143 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
146 unsigned long tb_ticks_per_jiffy
;
147 unsigned long tb_ticks_per_usec
= 100; /* sane default */
148 EXPORT_SYMBOL(tb_ticks_per_usec
);
149 unsigned long tb_ticks_per_sec
;
150 EXPORT_SYMBOL(tb_ticks_per_sec
); /* for cputime_t conversions */
154 #define TICKLEN_SCALE NTP_SCALE_SHIFT
155 static u64 last_tick_len
; /* units are ns / 2^TICKLEN_SCALE */
156 static u64 ticklen_to_xs
; /* 0.64 fraction */
158 /* If last_tick_len corresponds to about 1/HZ seconds, then
159 last_tick_len << TICKLEN_SHIFT will be about 2^63. */
160 #define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ)
162 DEFINE_SPINLOCK(rtc_lock
);
163 EXPORT_SYMBOL_GPL(rtc_lock
);
165 static u64 tb_to_ns_scale __read_mostly
;
166 static unsigned tb_to_ns_shift __read_mostly
;
167 static unsigned long boot_tb __read_mostly
;
169 extern struct timezone sys_tz
;
170 static long timezone_offset
;
172 unsigned long ppc_proc_freq
;
173 EXPORT_SYMBOL(ppc_proc_freq
);
174 unsigned long ppc_tb_freq
;
176 static u64 tb_last_jiffy __cacheline_aligned_in_smp
;
177 static DEFINE_PER_CPU(u64
, last_jiffy
);
179 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
181 * Factors for converting from cputime_t (timebase ticks) to
182 * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds).
183 * These are all stored as 0.64 fixed-point binary fractions.
185 u64 __cputime_jiffies_factor
;
186 EXPORT_SYMBOL(__cputime_jiffies_factor
);
187 u64 __cputime_msec_factor
;
188 EXPORT_SYMBOL(__cputime_msec_factor
);
189 u64 __cputime_sec_factor
;
190 EXPORT_SYMBOL(__cputime_sec_factor
);
191 u64 __cputime_clockt_factor
;
192 EXPORT_SYMBOL(__cputime_clockt_factor
);
193 DEFINE_PER_CPU(unsigned long, cputime_last_delta
);
194 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta
);
196 cputime_t cputime_one_jiffy
;
198 static void calc_cputime_factors(void)
200 struct div_result res
;
202 div128_by_32(HZ
, 0, tb_ticks_per_sec
, &res
);
203 __cputime_jiffies_factor
= res
.result_low
;
204 div128_by_32(1000, 0, tb_ticks_per_sec
, &res
);
205 __cputime_msec_factor
= res
.result_low
;
206 div128_by_32(1, 0, tb_ticks_per_sec
, &res
);
207 __cputime_sec_factor
= res
.result_low
;
208 div128_by_32(USER_HZ
, 0, tb_ticks_per_sec
, &res
);
209 __cputime_clockt_factor
= res
.result_low
;
213 * Read the PURR on systems that have it, otherwise the timebase.
215 static u64
read_purr(void)
217 if (cpu_has_feature(CPU_FTR_PURR
))
218 return mfspr(SPRN_PURR
);
223 * Read the SPURR on systems that have it, otherwise the purr
225 static u64
read_spurr(u64 purr
)
228 * cpus without PURR won't have a SPURR
229 * We already know the former when we use this, so tell gcc
231 if (cpu_has_feature(CPU_FTR_PURR
) && cpu_has_feature(CPU_FTR_SPURR
))
232 return mfspr(SPRN_SPURR
);
237 * Account time for a transition between system, hard irq
240 void account_system_vtime(struct task_struct
*tsk
)
242 u64 now
, nowscaled
, delta
, deltascaled
, sys_time
;
245 local_irq_save(flags
);
247 nowscaled
= read_spurr(now
);
248 delta
= now
- get_paca()->startpurr
;
249 deltascaled
= nowscaled
- get_paca()->startspurr
;
250 get_paca()->startpurr
= now
;
251 get_paca()->startspurr
= nowscaled
;
252 if (!in_interrupt()) {
253 /* deltascaled includes both user and system time.
254 * Hence scale it based on the purr ratio to estimate
256 sys_time
= get_paca()->system_time
;
257 if (get_paca()->user_time
)
258 deltascaled
= deltascaled
* sys_time
/
259 (sys_time
+ get_paca()->user_time
);
261 get_paca()->system_time
= 0;
263 if (in_irq() || idle_task(smp_processor_id()) != tsk
)
264 account_system_time(tsk
, 0, delta
, deltascaled
);
266 account_idle_time(delta
);
267 per_cpu(cputime_last_delta
, smp_processor_id()) = delta
;
268 per_cpu(cputime_scaled_last_delta
, smp_processor_id()) = deltascaled
;
269 local_irq_restore(flags
);
273 * Transfer the user and system times accumulated in the paca
274 * by the exception entry and exit code to the generic process
275 * user and system time records.
276 * Must be called with interrupts disabled.
278 void account_process_tick(struct task_struct
*tsk
, int user_tick
)
280 cputime_t utime
, utimescaled
;
282 utime
= get_paca()->user_time
;
283 get_paca()->user_time
= 0;
284 utimescaled
= cputime_to_scaled(utime
);
285 account_user_time(tsk
, utime
, utimescaled
);
289 * Stuff for accounting stolen time.
291 struct cpu_purr_data
{
292 int initialized
; /* thread is running */
293 u64 tb
; /* last TB value read */
294 u64 purr
; /* last PURR value read */
295 u64 spurr
; /* last SPURR value read */
299 * Each entry in the cpu_purr_data array is manipulated only by its
300 * "owner" cpu -- usually in the timer interrupt but also occasionally
301 * in process context for cpu online. As long as cpus do not touch
302 * each others' cpu_purr_data, disabling local interrupts is
303 * sufficient to serialize accesses.
305 static DEFINE_PER_CPU(struct cpu_purr_data
, cpu_purr_data
);
307 static void snapshot_tb_and_purr(void *data
)
310 struct cpu_purr_data
*p
= &__get_cpu_var(cpu_purr_data
);
312 local_irq_save(flags
);
313 p
->tb
= get_tb_or_rtc();
314 p
->purr
= mfspr(SPRN_PURR
);
317 local_irq_restore(flags
);
321 * Called during boot when all cpus have come up.
323 void snapshot_timebases(void)
325 if (!cpu_has_feature(CPU_FTR_PURR
))
327 on_each_cpu(snapshot_tb_and_purr
, NULL
, 1);
331 * Must be called with interrupts disabled.
333 void calculate_steal_time(void)
337 struct cpu_purr_data
*pme
;
339 pme
= &__get_cpu_var(cpu_purr_data
);
340 if (!pme
->initialized
)
341 return; /* !CPU_FTR_PURR or early in early boot */
343 purr
= mfspr(SPRN_PURR
);
344 stolen
= (tb
- pme
->tb
) - (purr
- pme
->purr
);
346 if (idle_task(smp_processor_id()) != current
)
347 account_steal_time(stolen
);
349 account_idle_time(stolen
);
355 #ifdef CONFIG_PPC_SPLPAR
357 * Must be called before the cpu is added to the online map when
358 * a cpu is being brought up at runtime.
360 static void snapshot_purr(void)
362 struct cpu_purr_data
*pme
;
365 if (!cpu_has_feature(CPU_FTR_PURR
))
367 local_irq_save(flags
);
368 pme
= &__get_cpu_var(cpu_purr_data
);
370 pme
->purr
= mfspr(SPRN_PURR
);
371 pme
->initialized
= 1;
372 local_irq_restore(flags
);
375 #endif /* CONFIG_PPC_SPLPAR */
377 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
378 #define calc_cputime_factors()
379 #define calculate_steal_time() do { } while (0)
382 #if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR))
383 #define snapshot_purr() do { } while (0)
387 * Called when a cpu comes up after the system has finished booting,
388 * i.e. as a result of a hotplug cpu action.
390 void snapshot_timebase(void)
392 __get_cpu_var(last_jiffy
) = get_tb_or_rtc();
396 void __delay(unsigned long loops
)
404 /* the RTCL register wraps at 1000000000 */
405 diff
= get_rtcl() - start
;
408 } while (diff
< loops
);
411 while (get_tbl() - start
< loops
)
416 EXPORT_SYMBOL(__delay
);
418 void udelay(unsigned long usecs
)
420 __delay(tb_ticks_per_usec
* usecs
);
422 EXPORT_SYMBOL(udelay
);
424 static inline void update_gtod(u64 new_tb_stamp
, u64 new_stamp_xsec
,
428 * tb_update_count is used to allow the userspace gettimeofday code
429 * to assure itself that it sees a consistent view of the tb_to_xs and
430 * stamp_xsec variables. It reads the tb_update_count, then reads
431 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
432 * the two values of tb_update_count match and are even then the
433 * tb_to_xs and stamp_xsec values are consistent. If not, then it
434 * loops back and reads them again until this criteria is met.
435 * We expect the caller to have done the first increment of
436 * vdso_data->tb_update_count already.
438 vdso_data
->tb_orig_stamp
= new_tb_stamp
;
439 vdso_data
->stamp_xsec
= new_stamp_xsec
;
440 vdso_data
->tb_to_xs
= new_tb_to_xs
;
441 vdso_data
->wtom_clock_sec
= wall_to_monotonic
.tv_sec
;
442 vdso_data
->wtom_clock_nsec
= wall_to_monotonic
.tv_nsec
;
443 vdso_data
->stamp_xtime
= xtime
;
445 ++(vdso_data
->tb_update_count
);
449 unsigned long profile_pc(struct pt_regs
*regs
)
451 unsigned long pc
= instruction_pointer(regs
);
453 if (in_lock_functions(pc
))
458 EXPORT_SYMBOL(profile_pc
);
461 #ifdef CONFIG_PPC_ISERIES
464 * This function recalibrates the timebase based on the 49-bit time-of-day
465 * value in the Titan chip. The Titan is much more accurate than the value
466 * returned by the service processor for the timebase frequency.
469 static int __init
iSeries_tb_recal(void)
471 struct div_result divres
;
472 unsigned long titan
, tb
;
474 /* Make sure we only run on iSeries */
475 if (!firmware_has_feature(FW_FEATURE_ISERIES
))
479 titan
= HvCallXm_loadTod();
480 if ( iSeries_recal_titan
) {
481 unsigned long tb_ticks
= tb
- iSeries_recal_tb
;
482 unsigned long titan_usec
= (titan
- iSeries_recal_titan
) >> 12;
483 unsigned long new_tb_ticks_per_sec
= (tb_ticks
* USEC_PER_SEC
)/titan_usec
;
484 unsigned long new_tb_ticks_per_jiffy
= (new_tb_ticks_per_sec
+(HZ
/2))/HZ
;
485 long tick_diff
= new_tb_ticks_per_jiffy
- tb_ticks_per_jiffy
;
487 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */
488 new_tb_ticks_per_sec
= new_tb_ticks_per_jiffy
* HZ
;
490 if ( tick_diff
< 0 ) {
491 tick_diff
= -tick_diff
;
495 if ( tick_diff
< tb_ticks_per_jiffy
/25 ) {
496 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n",
497 new_tb_ticks_per_jiffy
, sign
, tick_diff
);
498 tb_ticks_per_jiffy
= new_tb_ticks_per_jiffy
;
499 tb_ticks_per_sec
= new_tb_ticks_per_sec
;
500 calc_cputime_factors();
501 div128_by_32( XSEC_PER_SEC
, 0, tb_ticks_per_sec
, &divres
);
502 tb_to_xs
= divres
.result_low
;
503 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
504 vdso_data
->tb_to_xs
= tb_to_xs
;
505 setup_cputime_one_jiffy();
508 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n"
509 " new tb_ticks_per_jiffy = %lu\n"
510 " old tb_ticks_per_jiffy = %lu\n",
511 new_tb_ticks_per_jiffy
, tb_ticks_per_jiffy
);
515 iSeries_recal_titan
= titan
;
516 iSeries_recal_tb
= tb
;
518 /* Called here as now we know accurate values for the timebase */
522 late_initcall(iSeries_tb_recal
);
524 /* Called from platform early init */
525 void __init
iSeries_time_init_early(void)
527 iSeries_recal_tb
= get_tb();
528 iSeries_recal_titan
= HvCallXm_loadTod();
530 #endif /* CONFIG_PPC_ISERIES */
532 #if defined(CONFIG_PERF_COUNTERS) && defined(CONFIG_PPC32)
533 DEFINE_PER_CPU(u8
, perf_counter_pending
);
535 void set_perf_counter_pending(void)
537 get_cpu_var(perf_counter_pending
) = 1;
539 put_cpu_var(perf_counter_pending
);
542 #define test_perf_counter_pending() __get_cpu_var(perf_counter_pending)
543 #define clear_perf_counter_pending() __get_cpu_var(perf_counter_pending) = 0
545 #else /* CONFIG_PERF_COUNTERS && CONFIG_PPC32 */
547 #define test_perf_counter_pending() 0
548 #define clear_perf_counter_pending()
550 #endif /* CONFIG_PERF_COUNTERS && CONFIG_PPC32 */
553 * For iSeries shared processors, we have to let the hypervisor
554 * set the hardware decrementer. We set a virtual decrementer
555 * in the lppaca and call the hypervisor if the virtual
556 * decrementer is less than the current value in the hardware
557 * decrementer. (almost always the new decrementer value will
558 * be greater than the current hardware decementer so the hypervisor
559 * call will not be needed)
563 * timer_interrupt - gets called when the decrementer overflows,
564 * with interrupts disabled.
566 void timer_interrupt(struct pt_regs
* regs
)
568 struct pt_regs
*old_regs
;
569 struct decrementer_clock
*decrementer
= &__get_cpu_var(decrementers
);
570 struct clock_event_device
*evt
= &decrementer
->event
;
573 /* Ensure a positive value is written to the decrementer, or else
574 * some CPUs will continuue to take decrementer exceptions */
575 set_dec(DECREMENTER_MAX
);
578 if (test_perf_counter_pending()) {
579 clear_perf_counter_pending();
580 perf_counter_do_pending();
582 if (atomic_read(&ppc_n_lost_interrupts
) != 0)
586 now
= get_tb_or_rtc();
587 if (now
< decrementer
->next_tb
) {
588 /* not time for this event yet */
589 now
= decrementer
->next_tb
- now
;
590 if (now
<= DECREMENTER_MAX
)
594 old_regs
= set_irq_regs(regs
);
597 calculate_steal_time();
599 #ifdef CONFIG_PPC_ISERIES
600 if (firmware_has_feature(FW_FEATURE_ISERIES
))
601 get_lppaca()->int_dword
.fields
.decr_int
= 0;
604 if (evt
->event_handler
)
605 evt
->event_handler(evt
);
607 #ifdef CONFIG_PPC_ISERIES
608 if (firmware_has_feature(FW_FEATURE_ISERIES
) && hvlpevent_is_pending())
609 process_hvlpevents();
613 /* collect purr register values often, for accurate calculations */
614 if (firmware_has_feature(FW_FEATURE_SPLPAR
)) {
615 struct cpu_usage
*cu
= &__get_cpu_var(cpu_usage_array
);
616 cu
->current_tb
= mfspr(SPRN_PURR
);
621 set_irq_regs(old_regs
);
624 void wakeup_decrementer(void)
629 * The timebase gets saved on sleep and restored on wakeup,
630 * so all we need to do is to reset the decrementer.
632 ticks
= tb_ticks_since(__get_cpu_var(last_jiffy
));
633 if (ticks
< tb_ticks_per_jiffy
)
634 ticks
= tb_ticks_per_jiffy
- ticks
;
640 #ifdef CONFIG_SUSPEND
641 void generic_suspend_disable_irqs(void)
645 /* Disable the decrementer, so that it doesn't interfere
654 void generic_suspend_enable_irqs(void)
656 wakeup_decrementer();
662 /* Overrides the weak version in kernel/power/main.c */
663 void arch_suspend_disable_irqs(void)
665 if (ppc_md
.suspend_disable_irqs
)
666 ppc_md
.suspend_disable_irqs();
667 generic_suspend_disable_irqs();
670 /* Overrides the weak version in kernel/power/main.c */
671 void arch_suspend_enable_irqs(void)
673 generic_suspend_enable_irqs();
674 if (ppc_md
.suspend_enable_irqs
)
675 ppc_md
.suspend_enable_irqs();
680 void __init
smp_space_timers(unsigned int max_cpus
)
683 u64 previous_tb
= per_cpu(last_jiffy
, boot_cpuid
);
685 /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */
686 previous_tb
-= tb_ticks_per_jiffy
;
688 for_each_possible_cpu(i
) {
691 per_cpu(last_jiffy
, i
) = previous_tb
;
697 * Scheduler clock - returns current time in nanosec units.
699 * Note: mulhdu(a, b) (multiply high double unsigned) returns
700 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
701 * are 64-bit unsigned numbers.
703 unsigned long long sched_clock(void)
707 return mulhdu(get_tb() - boot_tb
, tb_to_ns_scale
) << tb_to_ns_shift
;
710 static int __init
get_freq(char *name
, int cells
, unsigned long *val
)
712 struct device_node
*cpu
;
713 const unsigned int *fp
;
716 /* The cpu node should have timebase and clock frequency properties */
717 cpu
= of_find_node_by_type(NULL
, "cpu");
720 fp
= of_get_property(cpu
, name
, NULL
);
723 *val
= of_read_ulong(fp
, cells
);
732 void __init
generic_calibrate_decr(void)
734 ppc_tb_freq
= DEFAULT_TB_FREQ
; /* hardcoded default */
736 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq
) &&
737 !get_freq("timebase-frequency", 1, &ppc_tb_freq
)) {
739 printk(KERN_ERR
"WARNING: Estimating decrementer frequency "
743 ppc_proc_freq
= DEFAULT_PROC_FREQ
; /* hardcoded default */
745 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq
) &&
746 !get_freq("clock-frequency", 1, &ppc_proc_freq
)) {
748 printk(KERN_ERR
"WARNING: Estimating processor frequency "
752 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
753 /* Clear any pending timer interrupts */
754 mtspr(SPRN_TSR
, TSR_ENW
| TSR_WIS
| TSR_DIS
| TSR_FIS
);
756 /* Enable decrementer interrupt */
757 mtspr(SPRN_TCR
, TCR_DIE
);
761 int update_persistent_clock(struct timespec now
)
765 if (!ppc_md
.set_rtc_time
)
768 to_tm(now
.tv_sec
+ 1 + timezone_offset
, &tm
);
772 return ppc_md
.set_rtc_time(&tm
);
775 unsigned long read_persistent_clock(void)
778 static int first
= 1;
780 /* XXX this is a litle fragile but will work okay in the short term */
783 if (ppc_md
.time_init
)
784 timezone_offset
= ppc_md
.time_init();
786 /* get_boot_time() isn't guaranteed to be safe to call late */
787 if (ppc_md
.get_boot_time
)
788 return ppc_md
.get_boot_time() -timezone_offset
;
790 if (!ppc_md
.get_rtc_time
)
792 ppc_md
.get_rtc_time(&tm
);
793 return mktime(tm
.tm_year
+1900, tm
.tm_mon
+1, tm
.tm_mday
,
794 tm
.tm_hour
, tm
.tm_min
, tm
.tm_sec
);
797 /* clocksource code */
798 static cycle_t
rtc_read(struct clocksource
*cs
)
800 return (cycle_t
)get_rtc();
803 static cycle_t
timebase_read(struct clocksource
*cs
)
805 return (cycle_t
)get_tb();
808 void update_vsyscall(struct timespec
*wall_time
, struct clocksource
*clock
)
812 if (clock
!= &clocksource_timebase
)
815 /* Make userspace gettimeofday spin until we're done. */
816 ++vdso_data
->tb_update_count
;
819 /* XXX this assumes clock->shift == 22 */
820 /* 4611686018 ~= 2^(20+64-22) / 1e9 */
821 t2x
= (u64
) clock
->mult
* 4611686018ULL;
822 stamp_xsec
= (u64
) xtime
.tv_nsec
* XSEC_PER_SEC
;
823 do_div(stamp_xsec
, 1000000000);
824 stamp_xsec
+= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
825 update_gtod(clock
->cycle_last
, stamp_xsec
, t2x
);
828 void update_vsyscall_tz(void)
830 /* Make userspace gettimeofday spin until we're done. */
831 ++vdso_data
->tb_update_count
;
833 vdso_data
->tz_minuteswest
= sys_tz
.tz_minuteswest
;
834 vdso_data
->tz_dsttime
= sys_tz
.tz_dsttime
;
836 ++vdso_data
->tb_update_count
;
839 static void __init
clocksource_init(void)
841 struct clocksource
*clock
;
844 clock
= &clocksource_rtc
;
846 clock
= &clocksource_timebase
;
848 clock
->mult
= clocksource_hz2mult(tb_ticks_per_sec
, clock
->shift
);
850 if (clocksource_register(clock
)) {
851 printk(KERN_ERR
"clocksource: %s is already registered\n",
856 printk(KERN_INFO
"clocksource: %s mult[%x] shift[%d] registered\n",
857 clock
->name
, clock
->mult
, clock
->shift
);
860 static int decrementer_set_next_event(unsigned long evt
,
861 struct clock_event_device
*dev
)
863 __get_cpu_var(decrementers
).next_tb
= get_tb_or_rtc() + evt
;
868 static void decrementer_set_mode(enum clock_event_mode mode
,
869 struct clock_event_device
*dev
)
871 if (mode
!= CLOCK_EVT_MODE_ONESHOT
)
872 decrementer_set_next_event(DECREMENTER_MAX
, dev
);
875 static void __init
setup_clockevent_multiplier(unsigned long hz
)
877 u64 mult
, shift
= 32;
880 mult
= div_sc(hz
, NSEC_PER_SEC
, shift
);
881 if (mult
&& (mult
>> 32UL) == 0UL)
887 decrementer_clockevent
.shift
= shift
;
888 decrementer_clockevent
.mult
= mult
;
891 static void register_decrementer_clockevent(int cpu
)
893 struct clock_event_device
*dec
= &per_cpu(decrementers
, cpu
).event
;
895 *dec
= decrementer_clockevent
;
896 dec
->cpumask
= cpumask_of(cpu
);
898 printk(KERN_DEBUG
"clockevent: %s mult[%lx] shift[%d] cpu[%d]\n",
899 dec
->name
, dec
->mult
, dec
->shift
, cpu
);
901 clockevents_register_device(dec
);
904 static void __init
init_decrementer_clockevent(void)
906 int cpu
= smp_processor_id();
908 setup_clockevent_multiplier(ppc_tb_freq
);
909 decrementer_clockevent
.max_delta_ns
=
910 clockevent_delta2ns(DECREMENTER_MAX
, &decrementer_clockevent
);
911 decrementer_clockevent
.min_delta_ns
=
912 clockevent_delta2ns(2, &decrementer_clockevent
);
914 register_decrementer_clockevent(cpu
);
917 void secondary_cpu_time_init(void)
919 /* FIME: Should make unrelatred change to move snapshot_timebase
921 register_decrementer_clockevent(smp_processor_id());
924 /* This function is only called on the boot processor */
925 void __init
time_init(void)
928 struct div_result res
;
933 /* 601 processor: dec counts down by 128 every 128ns */
934 ppc_tb_freq
= 1000000000;
935 tb_last_jiffy
= get_rtcl();
937 /* Normal PowerPC with timebase register */
938 ppc_md
.calibrate_decr();
939 printk(KERN_DEBUG
"time_init: decrementer frequency = %lu.%.6lu MHz\n",
940 ppc_tb_freq
/ 1000000, ppc_tb_freq
% 1000000);
941 printk(KERN_DEBUG
"time_init: processor frequency = %lu.%.6lu MHz\n",
942 ppc_proc_freq
/ 1000000, ppc_proc_freq
% 1000000);
943 tb_last_jiffy
= get_tb();
946 tb_ticks_per_jiffy
= ppc_tb_freq
/ HZ
;
947 tb_ticks_per_sec
= ppc_tb_freq
;
948 tb_ticks_per_usec
= ppc_tb_freq
/ 1000000;
949 tb_to_us
= mulhwu_scale_factor(ppc_tb_freq
, 1000000);
950 calc_cputime_factors();
951 setup_cputime_one_jiffy();
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
;
1004 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
1005 boot_tb
= get_tb_or_rtc();
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;
1015 vdso_data
->tb_orig_stamp
= tb_last_jiffy
;
1016 vdso_data
->tb_update_count
= 0;
1017 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
1018 vdso_data
->stamp_xsec
= (u64
) xtime
.tv_sec
* XSEC_PER_SEC
;
1019 vdso_data
->tb_to_xs
= tb_to_xs
;
1021 write_sequnlock_irqrestore(&xtime_lock
, flags
);
1023 /* Register the clocksource, if we're not running on iSeries */
1024 if (!firmware_has_feature(FW_FEATURE_ISERIES
))
1027 init_decrementer_clockevent();
1032 #define STARTOFTIME 1970
1033 #define SECDAY 86400L
1034 #define SECYR (SECDAY * 365)
1035 #define leapyear(year) ((year) % 4 == 0 && \
1036 ((year) % 100 != 0 || (year) % 400 == 0))
1037 #define days_in_year(a) (leapyear(a) ? 366 : 365)
1038 #define days_in_month(a) (month_days[(a) - 1])
1040 static int month_days
[12] = {
1041 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
1045 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
1047 void GregorianDay(struct rtc_time
* tm
)
1052 int MonthOffset
[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
1054 lastYear
= tm
->tm_year
- 1;
1057 * Number of leap corrections to apply up to end of last year
1059 leapsToDate
= lastYear
/ 4 - lastYear
/ 100 + lastYear
/ 400;
1062 * This year is a leap year if it is divisible by 4 except when it is
1063 * divisible by 100 unless it is divisible by 400
1065 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
1067 day
= tm
->tm_mon
> 2 && leapyear(tm
->tm_year
);
1069 day
+= lastYear
*365 + leapsToDate
+ MonthOffset
[tm
->tm_mon
-1] +
1072 tm
->tm_wday
= day
% 7;
1075 void to_tm(int tim
, struct rtc_time
* tm
)
1078 register long hms
, day
;
1083 /* Hours, minutes, seconds are easy */
1084 tm
->tm_hour
= hms
/ 3600;
1085 tm
->tm_min
= (hms
% 3600) / 60;
1086 tm
->tm_sec
= (hms
% 3600) % 60;
1088 /* Number of years in days */
1089 for (i
= STARTOFTIME
; day
>= days_in_year(i
); i
++)
1090 day
-= days_in_year(i
);
1093 /* Number of months in days left */
1094 if (leapyear(tm
->tm_year
))
1095 days_in_month(FEBRUARY
) = 29;
1096 for (i
= 1; day
>= days_in_month(i
); i
++)
1097 day
-= days_in_month(i
);
1098 days_in_month(FEBRUARY
) = 28;
1101 /* Days are what is left over (+1) from all that. */
1102 tm
->tm_mday
= day
+ 1;
1105 * Determine the day of week
1110 /* Auxiliary function to compute scaling factors */
1111 /* Actually the choice of a timebase running at 1/4 the of the bus
1112 * frequency giving resolution of a few tens of nanoseconds is quite nice.
1113 * It makes this computation very precise (27-28 bits typically) which
1114 * is optimistic considering the stability of most processor clock
1115 * oscillators and the precision with which the timebase frequency
1116 * is measured but does not harm.
1118 unsigned mulhwu_scale_factor(unsigned inscale
, unsigned outscale
)
1120 unsigned mlt
=0, tmp
, err
;
1121 /* No concern for performance, it's done once: use a stupid
1122 * but safe and compact method to find the multiplier.
1125 for (tmp
= 1U<<31; tmp
!= 0; tmp
>>= 1) {
1126 if (mulhwu(inscale
, mlt
|tmp
) < outscale
)
1130 /* We might still be off by 1 for the best approximation.
1131 * A side effect of this is that if outscale is too large
1132 * the returned value will be zero.
1133 * Many corner cases have been checked and seem to work,
1134 * some might have been forgotten in the test however.
1137 err
= inscale
* (mlt
+1);
1138 if (err
<= inscale
/2)
1144 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1147 void div128_by_32(u64 dividend_high
, u64 dividend_low
,
1148 unsigned divisor
, struct div_result
*dr
)
1150 unsigned long a
, b
, c
, d
;
1151 unsigned long w
, x
, y
, z
;
1154 a
= dividend_high
>> 32;
1155 b
= dividend_high
& 0xffffffff;
1156 c
= dividend_low
>> 32;
1157 d
= dividend_low
& 0xffffffff;
1160 ra
= ((u64
)(a
- (w
* divisor
)) << 32) + b
;
1162 rb
= ((u64
) do_div(ra
, divisor
) << 32) + c
;
1165 rc
= ((u64
) do_div(rb
, divisor
) << 32) + d
;
1168 do_div(rc
, divisor
);
1171 dr
->result_high
= ((u64
)w
<< 32) + x
;
1172 dr
->result_low
= ((u64
)y
<< 32) + z
;
1176 /* We don't need to calibrate delay, we use the CPU timebase for that */
1177 void calibrate_delay(void)
1179 /* Some generic code (such as spinlock debug) use loops_per_jiffy
1180 * as the number of __delay(1) in a jiffy, so make it so
1182 loops_per_jiffy
= tb_ticks_per_jiffy
;
1185 static int __init
rtc_init(void)
1187 struct platform_device
*pdev
;
1189 if (!ppc_md
.get_rtc_time
)
1192 pdev
= platform_device_register_simple("rtc-generic", -1, NULL
, 0);
1194 return PTR_ERR(pdev
);
1199 module_init(rtc_init
);