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/export.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/irq_work.h>
57 #include <asm/trace.h>
60 #include <asm/processor.h>
61 #include <asm/nvram.h>
62 #include <asm/cache.h>
63 #include <asm/machdep.h>
64 #include <asm/uaccess.h>
68 #include <asm/div64.h>
70 #include <asm/vdso_datapage.h>
71 #include <asm/firmware.h>
72 #include <asm/cputime.h>
73 #ifdef CONFIG_PPC_ISERIES
74 #include <asm/iseries/it_lp_queue.h>
75 #include <asm/iseries/hv_call_xm.h>
78 /* powerpc clocksource/clockevent code */
80 #include <linux/clockchips.h>
81 #include <linux/clocksource.h>
83 static cycle_t
rtc_read(struct clocksource
*);
84 static struct clocksource clocksource_rtc
= {
87 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
88 .mask
= CLOCKSOURCE_MASK(64),
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),
98 .read
= timebase_read
,
101 #define DECREMENTER_MAX 0x7fffffff
103 static int decrementer_set_next_event(unsigned long evt
,
104 struct clock_event_device
*dev
);
105 static void decrementer_set_mode(enum clock_event_mode mode
,
106 struct clock_event_device
*dev
);
108 static struct clock_event_device decrementer_clockevent
= {
109 .name
= "decrementer",
112 .set_next_event
= decrementer_set_next_event
,
113 .set_mode
= decrementer_set_mode
,
114 .features
= CLOCK_EVT_FEAT_ONESHOT
,
117 DEFINE_PER_CPU(u64
, decrementers_next_tb
);
118 static DEFINE_PER_CPU(struct clock_event_device
, decrementers
);
120 #ifdef CONFIG_PPC_ISERIES
121 static unsigned long __initdata iSeries_recal_titan
;
122 static signed long __initdata iSeries_recal_tb
;
124 /* Forward declaration is only needed for iSereis compiles */
125 static void __init
clocksource_init(void);
128 #define XSEC_PER_SEC (1024*1024)
131 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
133 /* compute ((xsec << 12) * max) >> 32 */
134 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
137 unsigned long tb_ticks_per_jiffy
;
138 unsigned long tb_ticks_per_usec
= 100; /* sane default */
139 EXPORT_SYMBOL(tb_ticks_per_usec
);
140 unsigned long tb_ticks_per_sec
;
141 EXPORT_SYMBOL(tb_ticks_per_sec
); /* for cputime_t conversions */
143 DEFINE_SPINLOCK(rtc_lock
);
144 EXPORT_SYMBOL_GPL(rtc_lock
);
146 static u64 tb_to_ns_scale __read_mostly
;
147 static unsigned tb_to_ns_shift __read_mostly
;
148 static u64 boot_tb __read_mostly
;
150 extern struct timezone sys_tz
;
151 static long timezone_offset
;
153 unsigned long ppc_proc_freq
;
154 EXPORT_SYMBOL_GPL(ppc_proc_freq
);
155 unsigned long ppc_tb_freq
;
156 EXPORT_SYMBOL_GPL(ppc_tb_freq
);
158 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
160 * Factors for converting from cputime_t (timebase ticks) to
161 * jiffies, microseconds, seconds, and clock_t (1/USER_HZ seconds).
162 * These are all stored as 0.64 fixed-point binary fractions.
164 u64 __cputime_jiffies_factor
;
165 EXPORT_SYMBOL(__cputime_jiffies_factor
);
166 u64 __cputime_usec_factor
;
167 EXPORT_SYMBOL(__cputime_usec_factor
);
168 u64 __cputime_sec_factor
;
169 EXPORT_SYMBOL(__cputime_sec_factor
);
170 u64 __cputime_clockt_factor
;
171 EXPORT_SYMBOL(__cputime_clockt_factor
);
172 DEFINE_PER_CPU(unsigned long, cputime_last_delta
);
173 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta
);
175 cputime_t cputime_one_jiffy
;
177 void (*dtl_consumer
)(struct dtl_entry
*, u64
);
179 static void calc_cputime_factors(void)
181 struct div_result res
;
183 div128_by_32(HZ
, 0, tb_ticks_per_sec
, &res
);
184 __cputime_jiffies_factor
= res
.result_low
;
185 div128_by_32(1000000, 0, tb_ticks_per_sec
, &res
);
186 __cputime_usec_factor
= res
.result_low
;
187 div128_by_32(1, 0, tb_ticks_per_sec
, &res
);
188 __cputime_sec_factor
= res
.result_low
;
189 div128_by_32(USER_HZ
, 0, tb_ticks_per_sec
, &res
);
190 __cputime_clockt_factor
= res
.result_low
;
194 * Read the SPURR on systems that have it, otherwise the PURR,
195 * or if that doesn't exist return the timebase value passed in.
197 static u64
read_spurr(u64 tb
)
199 if (cpu_has_feature(CPU_FTR_SPURR
))
200 return mfspr(SPRN_SPURR
);
201 if (cpu_has_feature(CPU_FTR_PURR
))
202 return mfspr(SPRN_PURR
);
206 #ifdef CONFIG_PPC_SPLPAR
209 * Scan the dispatch trace log and count up the stolen time.
210 * Should be called with interrupts disabled.
212 static u64
scan_dispatch_log(u64 stop_tb
)
214 u64 i
= local_paca
->dtl_ridx
;
215 struct dtl_entry
*dtl
= local_paca
->dtl_curr
;
216 struct dtl_entry
*dtl_end
= local_paca
->dispatch_log_end
;
217 struct lppaca
*vpa
= local_paca
->lppaca_ptr
;
225 if (i
== vpa
->dtl_idx
)
227 while (i
< vpa
->dtl_idx
) {
229 dtl_consumer(dtl
, i
);
231 tb_delta
= dtl
->enqueue_to_dispatch_time
+
232 dtl
->ready_to_enqueue_time
;
234 if (i
+ N_DISPATCH_LOG
< vpa
->dtl_idx
) {
235 /* buffer has overflowed */
236 i
= vpa
->dtl_idx
- N_DISPATCH_LOG
;
237 dtl
= local_paca
->dispatch_log
+ (i
% N_DISPATCH_LOG
);
246 dtl
= local_paca
->dispatch_log
;
248 local_paca
->dtl_ridx
= i
;
249 local_paca
->dtl_curr
= dtl
;
254 * Accumulate stolen time by scanning the dispatch trace log.
255 * Called on entry from user mode.
257 void accumulate_stolen_time(void)
261 u8 save_soft_enabled
= local_paca
->soft_enabled
;
263 /* We are called early in the exception entry, before
264 * soft/hard_enabled are sync'ed to the expected state
265 * for the exception. We are hard disabled but the PACA
266 * needs to reflect that so various debug stuff doesn't
269 local_paca
->soft_enabled
= 0;
271 sst
= scan_dispatch_log(local_paca
->starttime_user
);
272 ust
= scan_dispatch_log(local_paca
->starttime
);
273 local_paca
->system_time
-= sst
;
274 local_paca
->user_time
-= ust
;
275 local_paca
->stolen_time
+= ust
+ sst
;
277 local_paca
->soft_enabled
= save_soft_enabled
;
280 static inline u64
calculate_stolen_time(u64 stop_tb
)
284 if (get_paca()->dtl_ridx
!= get_paca()->lppaca_ptr
->dtl_idx
) {
285 stolen
= scan_dispatch_log(stop_tb
);
286 get_paca()->system_time
-= stolen
;
289 stolen
+= get_paca()->stolen_time
;
290 get_paca()->stolen_time
= 0;
294 #else /* CONFIG_PPC_SPLPAR */
295 static inline u64
calculate_stolen_time(u64 stop_tb
)
300 #endif /* CONFIG_PPC_SPLPAR */
303 * Account time for a transition between system, hard irq
306 void account_system_vtime(struct task_struct
*tsk
)
308 u64 now
, nowscaled
, delta
, deltascaled
;
310 u64 stolen
, udelta
, sys_scaled
, user_scaled
;
312 local_irq_save(flags
);
314 nowscaled
= read_spurr(now
);
315 get_paca()->system_time
+= now
- get_paca()->starttime
;
316 get_paca()->starttime
= now
;
317 deltascaled
= nowscaled
- get_paca()->startspurr
;
318 get_paca()->startspurr
= nowscaled
;
320 stolen
= calculate_stolen_time(now
);
322 delta
= get_paca()->system_time
;
323 get_paca()->system_time
= 0;
324 udelta
= get_paca()->user_time
- get_paca()->utime_sspurr
;
325 get_paca()->utime_sspurr
= get_paca()->user_time
;
328 * Because we don't read the SPURR on every kernel entry/exit,
329 * deltascaled includes both user and system SPURR ticks.
330 * Apportion these ticks to system SPURR ticks and user
331 * SPURR ticks in the same ratio as the system time (delta)
332 * and user time (udelta) values obtained from the timebase
333 * over the same interval. The system ticks get accounted here;
334 * the user ticks get saved up in paca->user_time_scaled to be
335 * used by account_process_tick.
338 user_scaled
= udelta
;
339 if (deltascaled
!= delta
+ udelta
) {
341 sys_scaled
= deltascaled
* delta
/ (delta
+ udelta
);
342 user_scaled
= deltascaled
- sys_scaled
;
344 sys_scaled
= deltascaled
;
347 get_paca()->user_time_scaled
+= user_scaled
;
349 if (in_interrupt() || idle_task(smp_processor_id()) != tsk
) {
350 account_system_time(tsk
, 0, delta
, sys_scaled
);
352 account_steal_time(stolen
);
354 account_idle_time(delta
+ stolen
);
356 local_irq_restore(flags
);
358 EXPORT_SYMBOL_GPL(account_system_vtime
);
361 * Transfer the user and system times accumulated in the paca
362 * by the exception entry and exit code to the generic process
363 * user and system time records.
364 * Must be called with interrupts disabled.
365 * Assumes that account_system_vtime() has been called recently
366 * (i.e. since the last entry from usermode) so that
367 * get_paca()->user_time_scaled is up to date.
369 void account_process_tick(struct task_struct
*tsk
, int user_tick
)
371 cputime_t utime
, utimescaled
;
373 utime
= get_paca()->user_time
;
374 utimescaled
= get_paca()->user_time_scaled
;
375 get_paca()->user_time
= 0;
376 get_paca()->user_time_scaled
= 0;
377 get_paca()->utime_sspurr
= 0;
378 account_user_time(tsk
, utime
, utimescaled
);
381 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
382 #define calc_cputime_factors()
385 void __delay(unsigned long loops
)
393 /* the RTCL register wraps at 1000000000 */
394 diff
= get_rtcl() - start
;
397 } while (diff
< loops
);
400 while (get_tbl() - start
< loops
)
405 EXPORT_SYMBOL(__delay
);
407 void udelay(unsigned long usecs
)
409 __delay(tb_ticks_per_usec
* usecs
);
411 EXPORT_SYMBOL(udelay
);
414 unsigned long profile_pc(struct pt_regs
*regs
)
416 unsigned long pc
= instruction_pointer(regs
);
418 if (in_lock_functions(pc
))
423 EXPORT_SYMBOL(profile_pc
);
426 #ifdef CONFIG_PPC_ISERIES
429 * This function recalibrates the timebase based on the 49-bit time-of-day
430 * value in the Titan chip. The Titan is much more accurate than the value
431 * returned by the service processor for the timebase frequency.
434 static int __init
iSeries_tb_recal(void)
436 unsigned long titan
, tb
;
438 /* Make sure we only run on iSeries */
439 if (!firmware_has_feature(FW_FEATURE_ISERIES
))
443 titan
= HvCallXm_loadTod();
444 if ( iSeries_recal_titan
) {
445 unsigned long tb_ticks
= tb
- iSeries_recal_tb
;
446 unsigned long titan_usec
= (titan
- iSeries_recal_titan
) >> 12;
447 unsigned long new_tb_ticks_per_sec
= (tb_ticks
* USEC_PER_SEC
)/titan_usec
;
448 unsigned long new_tb_ticks_per_jiffy
=
449 DIV_ROUND_CLOSEST(new_tb_ticks_per_sec
, HZ
);
450 long tick_diff
= new_tb_ticks_per_jiffy
- tb_ticks_per_jiffy
;
452 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */
453 new_tb_ticks_per_sec
= new_tb_ticks_per_jiffy
* HZ
;
455 if ( tick_diff
< 0 ) {
456 tick_diff
= -tick_diff
;
460 if ( tick_diff
< tb_ticks_per_jiffy
/25 ) {
461 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n",
462 new_tb_ticks_per_jiffy
, sign
, tick_diff
);
463 tb_ticks_per_jiffy
= new_tb_ticks_per_jiffy
;
464 tb_ticks_per_sec
= new_tb_ticks_per_sec
;
465 calc_cputime_factors();
466 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
467 setup_cputime_one_jiffy();
470 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n"
471 " new tb_ticks_per_jiffy = %lu\n"
472 " old tb_ticks_per_jiffy = %lu\n",
473 new_tb_ticks_per_jiffy
, tb_ticks_per_jiffy
);
477 iSeries_recal_titan
= titan
;
478 iSeries_recal_tb
= tb
;
480 /* Called here as now we know accurate values for the timebase */
484 late_initcall(iSeries_tb_recal
);
486 /* Called from platform early init */
487 void __init
iSeries_time_init_early(void)
489 iSeries_recal_tb
= get_tb();
490 iSeries_recal_titan
= HvCallXm_loadTod();
492 #endif /* CONFIG_PPC_ISERIES */
494 #ifdef CONFIG_IRQ_WORK
497 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable...
500 static inline unsigned long test_irq_work_pending(void)
504 asm volatile("lbz %0,%1(13)"
506 : "i" (offsetof(struct paca_struct
, irq_work_pending
)));
510 static inline void set_irq_work_pending_flag(void)
512 asm volatile("stb %0,%1(13)" : :
514 "i" (offsetof(struct paca_struct
, irq_work_pending
)));
517 static inline void clear_irq_work_pending(void)
519 asm volatile("stb %0,%1(13)" : :
521 "i" (offsetof(struct paca_struct
, irq_work_pending
)));
526 DEFINE_PER_CPU(u8
, irq_work_pending
);
528 #define set_irq_work_pending_flag() __get_cpu_var(irq_work_pending) = 1
529 #define test_irq_work_pending() __get_cpu_var(irq_work_pending)
530 #define clear_irq_work_pending() __get_cpu_var(irq_work_pending) = 0
532 #endif /* 32 vs 64 bit */
534 void arch_irq_work_raise(void)
537 set_irq_work_pending_flag();
542 #else /* CONFIG_IRQ_WORK */
544 #define test_irq_work_pending() 0
545 #define clear_irq_work_pending()
547 #endif /* CONFIG_IRQ_WORK */
550 * For iSeries shared processors, we have to let the hypervisor
551 * set the hardware decrementer. We set a virtual decrementer
552 * in the lppaca and call the hypervisor if the virtual
553 * decrementer is less than the current value in the hardware
554 * decrementer. (almost always the new decrementer value will
555 * be greater than the current hardware decementer so the hypervisor
556 * call will not be needed)
560 * timer_interrupt - gets called when the decrementer overflows,
561 * with interrupts disabled.
563 void timer_interrupt(struct pt_regs
* regs
)
565 struct pt_regs
*old_regs
;
566 u64
*next_tb
= &__get_cpu_var(decrementers_next_tb
);
567 struct clock_event_device
*evt
= &__get_cpu_var(decrementers
);
569 /* Ensure a positive value is written to the decrementer, or else
570 * some CPUs will continue to take decrementer exceptions.
572 set_dec(DECREMENTER_MAX
);
574 /* Some implementations of hotplug will get timer interrupts while
575 * offline, just ignore these
577 if (!cpu_online(smp_processor_id()))
580 /* Conditionally hard-enable interrupts now that the DEC has been
581 * bumped to its maximum value
583 may_hard_irq_enable();
585 trace_timer_interrupt_entry(regs
);
587 __get_cpu_var(irq_stat
).timer_irqs
++;
589 #if defined(CONFIG_PPC32) && defined(CONFIG_PMAC)
590 if (atomic_read(&ppc_n_lost_interrupts
) != 0)
594 old_regs
= set_irq_regs(regs
);
597 if (test_irq_work_pending()) {
598 clear_irq_work_pending();
602 #ifdef CONFIG_PPC_ISERIES
603 if (firmware_has_feature(FW_FEATURE_ISERIES
))
604 get_lppaca()->int_dword
.fields
.decr_int
= 0;
608 if (evt
->event_handler
)
609 evt
->event_handler(evt
);
611 #ifdef CONFIG_PPC_ISERIES
612 if (firmware_has_feature(FW_FEATURE_ISERIES
) && hvlpevent_is_pending())
613 process_hvlpevents();
617 /* collect purr register values often, for accurate calculations */
618 if (firmware_has_feature(FW_FEATURE_SPLPAR
)) {
619 struct cpu_usage
*cu
= &__get_cpu_var(cpu_usage_array
);
620 cu
->current_tb
= mfspr(SPRN_PURR
);
625 set_irq_regs(old_regs
);
627 trace_timer_interrupt_exit(regs
);
630 #ifdef CONFIG_SUSPEND
631 static void generic_suspend_disable_irqs(void)
633 /* Disable the decrementer, so that it doesn't interfere
637 set_dec(DECREMENTER_MAX
);
639 set_dec(DECREMENTER_MAX
);
642 static void generic_suspend_enable_irqs(void)
647 /* Overrides the weak version in kernel/power/main.c */
648 void arch_suspend_disable_irqs(void)
650 if (ppc_md
.suspend_disable_irqs
)
651 ppc_md
.suspend_disable_irqs();
652 generic_suspend_disable_irqs();
655 /* Overrides the weak version in kernel/power/main.c */
656 void arch_suspend_enable_irqs(void)
658 generic_suspend_enable_irqs();
659 if (ppc_md
.suspend_enable_irqs
)
660 ppc_md
.suspend_enable_irqs();
665 * Scheduler clock - returns current time in nanosec units.
667 * Note: mulhdu(a, b) (multiply high double unsigned) returns
668 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
669 * are 64-bit unsigned numbers.
671 unsigned long long sched_clock(void)
675 return mulhdu(get_tb() - boot_tb
, tb_to_ns_scale
) << tb_to_ns_shift
;
678 static int __init
get_freq(char *name
, int cells
, unsigned long *val
)
680 struct device_node
*cpu
;
681 const unsigned int *fp
;
684 /* The cpu node should have timebase and clock frequency properties */
685 cpu
= of_find_node_by_type(NULL
, "cpu");
688 fp
= of_get_property(cpu
, name
, NULL
);
691 *val
= of_read_ulong(fp
, cells
);
700 /* should become __cpuinit when secondary_cpu_time_init also is */
701 void start_cpu_decrementer(void)
703 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
704 /* Clear any pending timer interrupts */
705 mtspr(SPRN_TSR
, TSR_ENW
| TSR_WIS
| TSR_DIS
| TSR_FIS
);
707 /* Enable decrementer interrupt */
708 mtspr(SPRN_TCR
, TCR_DIE
);
709 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */
712 void __init
generic_calibrate_decr(void)
714 ppc_tb_freq
= DEFAULT_TB_FREQ
; /* hardcoded default */
716 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq
) &&
717 !get_freq("timebase-frequency", 1, &ppc_tb_freq
)) {
719 printk(KERN_ERR
"WARNING: Estimating decrementer frequency "
723 ppc_proc_freq
= DEFAULT_PROC_FREQ
; /* hardcoded default */
725 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq
) &&
726 !get_freq("clock-frequency", 1, &ppc_proc_freq
)) {
728 printk(KERN_ERR
"WARNING: Estimating processor frequency "
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 static void __read_persistent_clock(struct timespec
*ts
)
750 static int first
= 1;
753 /* XXX this is a litle fragile but will work okay in the short term */
756 if (ppc_md
.time_init
)
757 timezone_offset
= ppc_md
.time_init();
759 /* get_boot_time() isn't guaranteed to be safe to call late */
760 if (ppc_md
.get_boot_time
) {
761 ts
->tv_sec
= ppc_md
.get_boot_time() - timezone_offset
;
765 if (!ppc_md
.get_rtc_time
) {
769 ppc_md
.get_rtc_time(&tm
);
771 ts
->tv_sec
= mktime(tm
.tm_year
+1900, tm
.tm_mon
+1, tm
.tm_mday
,
772 tm
.tm_hour
, tm
.tm_min
, tm
.tm_sec
);
775 void read_persistent_clock(struct timespec
*ts
)
777 __read_persistent_clock(ts
);
779 /* Sanitize it in case real time clock is set below EPOCH */
780 if (ts
->tv_sec
< 0) {
787 /* clocksource code */
788 static cycle_t
rtc_read(struct clocksource
*cs
)
790 return (cycle_t
)get_rtc();
793 static cycle_t
timebase_read(struct clocksource
*cs
)
795 return (cycle_t
)get_tb();
798 void update_vsyscall(struct timespec
*wall_time
, struct timespec
*wtm
,
799 struct clocksource
*clock
, u32 mult
)
801 u64 new_tb_to_xs
, new_stamp_xsec
;
804 if (clock
!= &clocksource_timebase
)
807 /* Make userspace gettimeofday spin until we're done. */
808 ++vdso_data
->tb_update_count
;
811 /* 19342813113834067 ~= 2^(20+64) / 1e9 */
812 new_tb_to_xs
= (u64
) mult
* (19342813113834067ULL >> clock
->shift
);
813 new_stamp_xsec
= (u64
) wall_time
->tv_nsec
* XSEC_PER_SEC
;
814 do_div(new_stamp_xsec
, 1000000000);
815 new_stamp_xsec
+= (u64
) wall_time
->tv_sec
* XSEC_PER_SEC
;
817 BUG_ON(wall_time
->tv_nsec
>= NSEC_PER_SEC
);
818 /* this is tv_nsec / 1e9 as a 0.32 fraction */
819 frac_sec
= ((u64
) wall_time
->tv_nsec
* 18446744073ULL) >> 32;
822 * tb_update_count is used to allow the userspace gettimeofday code
823 * to assure itself that it sees a consistent view of the tb_to_xs and
824 * stamp_xsec variables. It reads the tb_update_count, then reads
825 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
826 * the two values of tb_update_count match and are even then the
827 * tb_to_xs and stamp_xsec values are consistent. If not, then it
828 * loops back and reads them again until this criteria is met.
829 * We expect the caller to have done the first increment of
830 * vdso_data->tb_update_count already.
832 vdso_data
->tb_orig_stamp
= clock
->cycle_last
;
833 vdso_data
->stamp_xsec
= new_stamp_xsec
;
834 vdso_data
->tb_to_xs
= new_tb_to_xs
;
835 vdso_data
->wtom_clock_sec
= wtm
->tv_sec
;
836 vdso_data
->wtom_clock_nsec
= wtm
->tv_nsec
;
837 vdso_data
->stamp_xtime
= *wall_time
;
838 vdso_data
->stamp_sec_fraction
= frac_sec
;
840 ++(vdso_data
->tb_update_count
);
843 void update_vsyscall_tz(void)
845 /* Make userspace gettimeofday spin until we're done. */
846 ++vdso_data
->tb_update_count
;
848 vdso_data
->tz_minuteswest
= sys_tz
.tz_minuteswest
;
849 vdso_data
->tz_dsttime
= sys_tz
.tz_dsttime
;
851 ++vdso_data
->tb_update_count
;
854 static void __init
clocksource_init(void)
856 struct clocksource
*clock
;
859 clock
= &clocksource_rtc
;
861 clock
= &clocksource_timebase
;
863 if (clocksource_register_hz(clock
, tb_ticks_per_sec
)) {
864 printk(KERN_ERR
"clocksource: %s is already registered\n",
869 printk(KERN_INFO
"clocksource: %s mult[%x] shift[%d] registered\n",
870 clock
->name
, clock
->mult
, clock
->shift
);
873 static int decrementer_set_next_event(unsigned long evt
,
874 struct clock_event_device
*dev
)
876 __get_cpu_var(decrementers_next_tb
) = get_tb_or_rtc() + evt
;
881 static void decrementer_set_mode(enum clock_event_mode mode
,
882 struct clock_event_device
*dev
)
884 if (mode
!= CLOCK_EVT_MODE_ONESHOT
)
885 decrementer_set_next_event(DECREMENTER_MAX
, dev
);
888 static void register_decrementer_clockevent(int cpu
)
890 struct clock_event_device
*dec
= &per_cpu(decrementers
, cpu
);
892 *dec
= decrementer_clockevent
;
893 dec
->cpumask
= cpumask_of(cpu
);
895 printk_once(KERN_DEBUG
"clockevent: %s mult[%x] shift[%d] cpu[%d]\n",
896 dec
->name
, dec
->mult
, dec
->shift
, cpu
);
898 clockevents_register_device(dec
);
901 static void __init
init_decrementer_clockevent(void)
903 int cpu
= smp_processor_id();
905 clockevents_calc_mult_shift(&decrementer_clockevent
, ppc_tb_freq
, 4);
907 decrementer_clockevent
.max_delta_ns
=
908 clockevent_delta2ns(DECREMENTER_MAX
, &decrementer_clockevent
);
909 decrementer_clockevent
.min_delta_ns
=
910 clockevent_delta2ns(2, &decrementer_clockevent
);
912 register_decrementer_clockevent(cpu
);
915 void secondary_cpu_time_init(void)
917 /* Start the decrementer on CPUs that have manual control
920 start_cpu_decrementer();
922 /* FIME: Should make unrelatred change to move snapshot_timebase
924 register_decrementer_clockevent(smp_processor_id());
927 /* This function is only called on the boot processor */
928 void __init
time_init(void)
930 struct div_result res
;
935 /* 601 processor: dec counts down by 128 every 128ns */
936 ppc_tb_freq
= 1000000000;
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);
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 calc_cputime_factors();
950 setup_cputime_one_jiffy();
953 * Compute scale factor for sched_clock.
954 * The calibrate_decr() function has set tb_ticks_per_sec,
955 * which is the timebase frequency.
956 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
957 * the 128-bit result as a 64.64 fixed-point number.
958 * We then shift that number right until it is less than 1.0,
959 * giving us the scale factor and shift count to use in
962 div128_by_32(1000000000, 0, tb_ticks_per_sec
, &res
);
963 scale
= res
.result_low
;
964 for (shift
= 0; res
.result_high
!= 0; ++shift
) {
965 scale
= (scale
>> 1) | (res
.result_high
<< 63);
966 res
.result_high
>>= 1;
968 tb_to_ns_scale
= scale
;
969 tb_to_ns_shift
= shift
;
970 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
971 boot_tb
= get_tb_or_rtc();
973 /* If platform provided a timezone (pmac), we correct the time */
974 if (timezone_offset
) {
975 sys_tz
.tz_minuteswest
= -timezone_offset
/ 60;
976 sys_tz
.tz_dsttime
= 0;
979 vdso_data
->tb_update_count
= 0;
980 vdso_data
->tb_ticks_per_sec
= tb_ticks_per_sec
;
982 /* Start the decrementer on CPUs that have manual control
985 start_cpu_decrementer();
987 /* Register the clocksource, if we're not running on iSeries */
988 if (!firmware_has_feature(FW_FEATURE_ISERIES
))
991 init_decrementer_clockevent();
996 #define STARTOFTIME 1970
997 #define SECDAY 86400L
998 #define SECYR (SECDAY * 365)
999 #define leapyear(year) ((year) % 4 == 0 && \
1000 ((year) % 100 != 0 || (year) % 400 == 0))
1001 #define days_in_year(a) (leapyear(a) ? 366 : 365)
1002 #define days_in_month(a) (month_days[(a) - 1])
1004 static int month_days
[12] = {
1005 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
1009 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
1011 void GregorianDay(struct rtc_time
* tm
)
1016 int MonthOffset
[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
1018 lastYear
= tm
->tm_year
- 1;
1021 * Number of leap corrections to apply up to end of last year
1023 leapsToDate
= lastYear
/ 4 - lastYear
/ 100 + lastYear
/ 400;
1026 * This year is a leap year if it is divisible by 4 except when it is
1027 * divisible by 100 unless it is divisible by 400
1029 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
1031 day
= tm
->tm_mon
> 2 && leapyear(tm
->tm_year
);
1033 day
+= lastYear
*365 + leapsToDate
+ MonthOffset
[tm
->tm_mon
-1] +
1036 tm
->tm_wday
= day
% 7;
1039 void to_tm(int tim
, struct rtc_time
* tm
)
1042 register long hms
, day
;
1047 /* Hours, minutes, seconds are easy */
1048 tm
->tm_hour
= hms
/ 3600;
1049 tm
->tm_min
= (hms
% 3600) / 60;
1050 tm
->tm_sec
= (hms
% 3600) % 60;
1052 /* Number of years in days */
1053 for (i
= STARTOFTIME
; day
>= days_in_year(i
); i
++)
1054 day
-= days_in_year(i
);
1057 /* Number of months in days left */
1058 if (leapyear(tm
->tm_year
))
1059 days_in_month(FEBRUARY
) = 29;
1060 for (i
= 1; day
>= days_in_month(i
); i
++)
1061 day
-= days_in_month(i
);
1062 days_in_month(FEBRUARY
) = 28;
1065 /* Days are what is left over (+1) from all that. */
1066 tm
->tm_mday
= day
+ 1;
1069 * Determine the day of week
1075 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1078 void div128_by_32(u64 dividend_high
, u64 dividend_low
,
1079 unsigned divisor
, struct div_result
*dr
)
1081 unsigned long a
, b
, c
, d
;
1082 unsigned long w
, x
, y
, z
;
1085 a
= dividend_high
>> 32;
1086 b
= dividend_high
& 0xffffffff;
1087 c
= dividend_low
>> 32;
1088 d
= dividend_low
& 0xffffffff;
1091 ra
= ((u64
)(a
- (w
* divisor
)) << 32) + b
;
1093 rb
= ((u64
) do_div(ra
, divisor
) << 32) + c
;
1096 rc
= ((u64
) do_div(rb
, divisor
) << 32) + d
;
1099 do_div(rc
, divisor
);
1102 dr
->result_high
= ((u64
)w
<< 32) + x
;
1103 dr
->result_low
= ((u64
)y
<< 32) + z
;
1107 /* We don't need to calibrate delay, we use the CPU timebase for that */
1108 void calibrate_delay(void)
1110 /* Some generic code (such as spinlock debug) use loops_per_jiffy
1111 * as the number of __delay(1) in a jiffy, so make it so
1113 loops_per_jiffy
= tb_ticks_per_jiffy
;
1116 static int __init
rtc_init(void)
1118 struct platform_device
*pdev
;
1120 if (!ppc_md
.get_rtc_time
)
1123 pdev
= platform_device_register_simple("rtc-generic", -1, NULL
, 0);
1125 return PTR_ERR(pdev
);
1130 module_init(rtc_init
);