blob: a925a8eae121e1946c8d39959775b4b07de1c561 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * Common time routines among all ppc machines.
3 *
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)
8 *
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).
14 *
15 * Speeded up do_gettimeofday by getting rid of references to
16 * xtime (which required locks for consistency). (mikejc@us.ibm.com)
17 *
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.
25 *
26 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
27 * "A Kernel Model for Precision Timekeeping" by Dave Mills
28 *
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.
33 */
34
Linus Torvalds1da177e2005-04-16 15:20:36 -070035#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>
41#include <linux/mm.h>
42#include <linux/interrupt.h>
43#include <linux/timex.h>
44#include <linux/kernel_stat.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070045#include <linux/time.h>
46#include <linux/init.h>
47#include <linux/profile.h>
48#include <linux/cpu.h>
49#include <linux/security.h>
Paul Mackerrasf2783c12005-10-20 09:23:26 +100050#include <linux/percpu.h>
51#include <linux/rtc.h>
Paul Mackerras092b8f32006-02-20 10:38:56 +110052#include <linux/jiffies.h>
Paul Mackerrasc6622f62006-02-24 10:06:59 +110053#include <linux/posix-timers.h>
David Howells7d12e782006-10-05 14:55:46 +010054#include <linux/irq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
Linus Torvalds1da177e2005-04-16 15:20:36 -070056#include <asm/io.h>
57#include <asm/processor.h>
58#include <asm/nvram.h>
59#include <asm/cache.h>
60#include <asm/machdep.h>
Paul Mackerrasf2783c12005-10-20 09:23:26 +100061#include <asm/uaccess.h>
62#include <asm/time.h>
63#include <asm/prom.h>
64#include <asm/irq.h>
65#include <asm/div64.h>
Paul Mackerras2249ca92005-11-07 13:18:13 +110066#include <asm/smp.h>
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +110067#include <asm/vdso_datapage.h>
Paul Mackerrasf2783c12005-10-20 09:23:26 +100068#include <asm/firmware.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070069#ifdef CONFIG_PPC_ISERIES
Kelly Daly8875ccf2005-11-02 14:13:34 +110070#include <asm/iseries/it_lp_queue.h>
Kelly Daly8021b8a2005-11-02 11:41:12 +110071#include <asm/iseries/hv_call_xm.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070072#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
Tony Breeds4a4cfe32007-09-22 07:35:52 +100074/* powerpc clocksource/clockevent code */
75
Tony Breedsd831d0b2007-09-21 13:26:03 +100076#include <linux/clockchips.h>
Tony Breeds4a4cfe32007-09-22 07:35:52 +100077#include <linux/clocksource.h>
78
79static cycle_t rtc_read(void);
80static struct clocksource clocksource_rtc = {
81 .name = "rtc",
82 .rating = 400,
83 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
84 .mask = CLOCKSOURCE_MASK(64),
85 .shift = 22,
86 .mult = 0, /* To be filled in */
87 .read = rtc_read,
88};
89
90static cycle_t timebase_read(void);
91static struct clocksource clocksource_timebase = {
92 .name = "timebase",
93 .rating = 400,
94 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
95 .mask = CLOCKSOURCE_MASK(64),
96 .shift = 22,
97 .mult = 0, /* To be filled in */
98 .read = timebase_read,
99};
100
Tony Breedsd831d0b2007-09-21 13:26:03 +1000101#define DECREMENTER_MAX 0x7fffffff
102
103static int decrementer_set_next_event(unsigned long evt,
104 struct clock_event_device *dev);
105static void decrementer_set_mode(enum clock_event_mode mode,
106 struct clock_event_device *dev);
107
108static struct clock_event_device decrementer_clockevent = {
109 .name = "decrementer",
110 .rating = 200,
Paul Mackerrascdec12a2007-10-11 21:46:45 +1000111 .shift = 16,
Tony Breedsd831d0b2007-09-21 13:26:03 +1000112 .mult = 0, /* To be filled in */
113 .irq = 0,
114 .set_next_event = decrementer_set_next_event,
115 .set_mode = decrementer_set_mode,
116 .features = CLOCK_EVT_FEAT_ONESHOT,
117};
118
119static DEFINE_PER_CPU(struct clock_event_device, decrementers);
120void init_decrementer_clockevent(void);
Paul Mackerrasd9680142007-10-09 09:59:17 +1000121static DEFINE_PER_CPU(u64, decrementer_next_tb);
Tony Breedsd831d0b2007-09-21 13:26:03 +1000122
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123#ifdef CONFIG_PPC_ISERIES
Tony Breeds71712b42007-06-22 16:54:30 +1000124static unsigned long __initdata iSeries_recal_titan;
125static signed long __initdata iSeries_recal_tb;
Tony Breeds4a4cfe32007-09-22 07:35:52 +1000126
127/* Forward declaration is only needed for iSereis compiles */
128void __init clocksource_init(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129#endif
130
131#define XSEC_PER_SEC (1024*1024)
132
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000133#ifdef CONFIG_PPC64
134#define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
135#else
136/* compute ((xsec << 12) * max) >> 32 */
137#define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
138#endif
139
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140unsigned long tb_ticks_per_jiffy;
141unsigned long tb_ticks_per_usec = 100; /* sane default */
142EXPORT_SYMBOL(tb_ticks_per_usec);
143unsigned long tb_ticks_per_sec;
Paul Mackerras2cf82c02006-02-27 15:41:47 +1100144EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000145u64 tb_to_xs;
146unsigned tb_to_us;
Paul Mackerras092b8f32006-02-20 10:38:56 +1100147
Roman Zippel19923c12006-06-26 00:25:18 -0700148#define TICKLEN_SCALE TICK_LENGTH_SHIFT
Paul Mackerras092b8f32006-02-20 10:38:56 +1100149u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */
150u64 ticklen_to_xs; /* 0.64 fraction */
151
152/* If last_tick_len corresponds to about 1/HZ seconds, then
153 last_tick_len << TICKLEN_SHIFT will be about 2^63. */
154#define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ)
155
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156DEFINE_SPINLOCK(rtc_lock);
Benjamin Herrenschmidt6ae3db12005-06-27 14:36:35 -0700157EXPORT_SYMBOL_GPL(rtc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158
Tony Breedsfc9069fe2007-07-04 14:04:31 +1000159static u64 tb_to_ns_scale __read_mostly;
160static unsigned tb_to_ns_shift __read_mostly;
161static unsigned long boot_tb __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162
163struct gettimeofday_struct do_gtod;
164
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165extern struct timezone sys_tz;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000166static long timezone_offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000168unsigned long ppc_proc_freq;
Bob Nelson14748552007-07-20 21:39:53 +0200169EXPORT_SYMBOL(ppc_proc_freq);
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000170unsigned long ppc_tb_freq;
171
Paul Mackerraseb36c282006-08-30 16:13:16 +1000172static u64 tb_last_jiffy __cacheline_aligned_in_smp;
173static DEFINE_PER_CPU(u64, last_jiffy);
Paul Mackerras96c44502005-10-23 17:14:56 +1000174
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100175#ifdef CONFIG_VIRT_CPU_ACCOUNTING
176/*
177 * Factors for converting from cputime_t (timebase ticks) to
178 * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds).
179 * These are all stored as 0.64 fixed-point binary fractions.
180 */
181u64 __cputime_jiffies_factor;
Paul Mackerras2cf82c02006-02-27 15:41:47 +1100182EXPORT_SYMBOL(__cputime_jiffies_factor);
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100183u64 __cputime_msec_factor;
Paul Mackerras2cf82c02006-02-27 15:41:47 +1100184EXPORT_SYMBOL(__cputime_msec_factor);
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100185u64 __cputime_sec_factor;
Paul Mackerras2cf82c02006-02-27 15:41:47 +1100186EXPORT_SYMBOL(__cputime_sec_factor);
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100187u64 __cputime_clockt_factor;
Paul Mackerras2cf82c02006-02-27 15:41:47 +1100188EXPORT_SYMBOL(__cputime_clockt_factor);
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100189
190static void calc_cputime_factors(void)
191{
192 struct div_result res;
193
194 div128_by_32(HZ, 0, tb_ticks_per_sec, &res);
195 __cputime_jiffies_factor = res.result_low;
196 div128_by_32(1000, 0, tb_ticks_per_sec, &res);
197 __cputime_msec_factor = res.result_low;
198 div128_by_32(1, 0, tb_ticks_per_sec, &res);
199 __cputime_sec_factor = res.result_low;
200 div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res);
201 __cputime_clockt_factor = res.result_low;
202}
203
204/*
205 * Read the PURR on systems that have it, otherwise the timebase.
206 */
207static u64 read_purr(void)
208{
209 if (cpu_has_feature(CPU_FTR_PURR))
210 return mfspr(SPRN_PURR);
211 return mftb();
212}
213
214/*
Michael Neuling4603ac12007-10-18 03:06:37 -0700215 * Read the SPURR on systems that have it, otherwise the purr
216 */
217static u64 read_spurr(u64 purr)
218{
219 if (cpu_has_feature(CPU_FTR_SPURR))
220 return mfspr(SPRN_SPURR);
221 return purr;
222}
223
224/*
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100225 * Account time for a transition between system, hard irq
226 * or soft irq state.
227 */
228void account_system_vtime(struct task_struct *tsk)
229{
Michael Neuling4603ac12007-10-18 03:06:37 -0700230 u64 now, nowscaled, delta, deltascaled;
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100231 unsigned long flags;
232
233 local_irq_save(flags);
234 now = read_purr();
235 delta = now - get_paca()->startpurr;
236 get_paca()->startpurr = now;
Michael Neuling4603ac12007-10-18 03:06:37 -0700237 nowscaled = read_spurr(now);
238 deltascaled = nowscaled - get_paca()->startspurr;
239 get_paca()->startspurr = nowscaled;
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100240 if (!in_interrupt()) {
Michael Neuling4603ac12007-10-18 03:06:37 -0700241 /* deltascaled includes both user and system time.
242 * Hence scale it based on the purr ratio to estimate
243 * the system time */
Michael Neuling2b46b562007-11-20 15:18:40 +1100244 if (get_paca()->user_time)
245 deltascaled = deltascaled * get_paca()->system_time /
246 (get_paca()->system_time + get_paca()->user_time);
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100247 delta += get_paca()->system_time;
248 get_paca()->system_time = 0;
249 }
250 account_system_time(tsk, 0, delta);
Michael Neuling4603ac12007-10-18 03:06:37 -0700251 get_paca()->purrdelta = delta;
252 account_system_time_scaled(tsk, deltascaled);
253 get_paca()->spurrdelta = deltascaled;
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100254 local_irq_restore(flags);
255}
256
257/*
258 * Transfer the user and system times accumulated in the paca
259 * by the exception entry and exit code to the generic process
260 * user and system time records.
261 * Must be called with interrupts disabled.
262 */
Paul Mackerrasfa13a5a2007-11-09 22:39:38 +0100263void account_process_tick(struct task_struct *tsk, int user_tick)
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100264{
Michael Neuling4603ac12007-10-18 03:06:37 -0700265 cputime_t utime, utimescaled;
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100266
267 utime = get_paca()->user_time;
268 get_paca()->user_time = 0;
269 account_user_time(tsk, utime);
Michael Neuling4603ac12007-10-18 03:06:37 -0700270
271 /* Estimate the scaled utime by scaling the real utime based
272 * on the last spurr to purr ratio */
273 utimescaled = utime * get_paca()->spurrdelta / get_paca()->purrdelta;
274 get_paca()->spurrdelta = get_paca()->purrdelta = 0;
275 account_user_time_scaled(tsk, utimescaled);
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100276}
277
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100278/*
279 * Stuff for accounting stolen time.
280 */
281struct cpu_purr_data {
282 int initialized; /* thread is running */
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100283 u64 tb; /* last TB value read */
284 u64 purr; /* last PURR value read */
Michael Neuling4603ac12007-10-18 03:06:37 -0700285 u64 spurr; /* last SPURR value read */
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100286};
287
Nathan Lynchdf211c82007-05-23 10:51:25 +1000288/*
289 * Each entry in the cpu_purr_data array is manipulated only by its
290 * "owner" cpu -- usually in the timer interrupt but also occasionally
291 * in process context for cpu online. As long as cpus do not touch
292 * each others' cpu_purr_data, disabling local interrupts is
293 * sufficient to serialize accesses.
294 */
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100295static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data);
296
297static void snapshot_tb_and_purr(void *data)
298{
Nathan Lynchdf211c82007-05-23 10:51:25 +1000299 unsigned long flags;
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100300 struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data);
301
Nathan Lynchdf211c82007-05-23 10:51:25 +1000302 local_irq_save(flags);
Benjamin Herrenschmidtc27da3392007-09-19 14:21:56 +1000303 p->tb = get_tb_or_rtc();
Stephen Rothwellcbcdb932006-10-17 23:08:35 +1000304 p->purr = mfspr(SPRN_PURR);
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100305 wmb();
306 p->initialized = 1;
Nathan Lynchdf211c82007-05-23 10:51:25 +1000307 local_irq_restore(flags);
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100308}
309
310/*
311 * Called during boot when all cpus have come up.
312 */
313void snapshot_timebases(void)
314{
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100315 if (!cpu_has_feature(CPU_FTR_PURR))
316 return;
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100317 on_each_cpu(snapshot_tb_and_purr, NULL, 0, 1);
318}
319
Nathan Lynchdf211c82007-05-23 10:51:25 +1000320/*
321 * Must be called with interrupts disabled.
322 */
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100323void calculate_steal_time(void)
324{
Stephen Rothwellcbcdb932006-10-17 23:08:35 +1000325 u64 tb, purr;
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100326 s64 stolen;
Stephen Rothwellcbcdb932006-10-17 23:08:35 +1000327 struct cpu_purr_data *pme;
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100328
329 if (!cpu_has_feature(CPU_FTR_PURR))
330 return;
Stephen Rothwellcbcdb932006-10-17 23:08:35 +1000331 pme = &per_cpu(cpu_purr_data, smp_processor_id());
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100332 if (!pme->initialized)
333 return; /* this can happen in early boot */
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100334 tb = mftb();
Stephen Rothwellcbcdb932006-10-17 23:08:35 +1000335 purr = mfspr(SPRN_PURR);
336 stolen = (tb - pme->tb) - (purr - pme->purr);
337 if (stolen > 0)
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100338 account_steal_time(current, stolen);
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100339 pme->tb = tb;
340 pme->purr = purr;
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100341}
342
Michael Neuling4cefebb12007-06-08 13:18:50 +1000343#ifdef CONFIG_PPC_SPLPAR
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100344/*
345 * Must be called before the cpu is added to the online map when
346 * a cpu is being brought up at runtime.
347 */
348static void snapshot_purr(void)
349{
Stephen Rothwellcbcdb932006-10-17 23:08:35 +1000350 struct cpu_purr_data *pme;
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100351 unsigned long flags;
352
353 if (!cpu_has_feature(CPU_FTR_PURR))
354 return;
Nathan Lynchdf211c82007-05-23 10:51:25 +1000355 local_irq_save(flags);
Stephen Rothwellcbcdb932006-10-17 23:08:35 +1000356 pme = &per_cpu(cpu_purr_data, smp_processor_id());
Stephen Rothwellcbcdb932006-10-17 23:08:35 +1000357 pme->tb = mftb();
358 pme->purr = mfspr(SPRN_PURR);
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100359 pme->initialized = 1;
Nathan Lynchdf211c82007-05-23 10:51:25 +1000360 local_irq_restore(flags);
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100361}
362
363#endif /* CONFIG_PPC_SPLPAR */
364
365#else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
366#define calc_cputime_factors()
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100367#define calculate_steal_time() do { } while (0)
368#endif
369
370#if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR))
371#define snapshot_purr() do { } while (0)
372#endif
373
374/*
375 * Called when a cpu comes up after the system has finished booting,
376 * i.e. as a result of a hotplug cpu action.
377 */
378void snapshot_timebase(void)
379{
Benjamin Herrenschmidtc27da3392007-09-19 14:21:56 +1000380 __get_cpu_var(last_jiffy) = get_tb_or_rtc();
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100381 snapshot_purr();
382}
383
Paul Mackerras6defa382005-11-18 13:44:17 +1100384void __delay(unsigned long loops)
385{
386 unsigned long start;
387 int diff;
388
389 if (__USE_RTC()) {
390 start = get_rtcl();
391 do {
392 /* the RTCL register wraps at 1000000000 */
393 diff = get_rtcl() - start;
394 if (diff < 0)
395 diff += 1000000000;
396 } while (diff < loops);
397 } else {
398 start = get_tbl();
399 while (get_tbl() - start < loops)
400 HMT_low();
401 HMT_medium();
402 }
403}
404EXPORT_SYMBOL(__delay);
405
406void udelay(unsigned long usecs)
407{
408 __delay(tb_ticks_per_usec * usecs);
409}
410EXPORT_SYMBOL(udelay);
411
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000413/*
414 * There are two copies of tb_to_xs and stamp_xsec so that no
415 * lock is needed to access and use these values in
416 * do_gettimeofday. We alternate the copies and as long as a
417 * reasonable time elapses between changes, there will never
418 * be inconsistent values. ntpd has a minimum of one minute
419 * between updates.
420 */
421static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
Paul Mackerras5d14a182005-10-20 22:33:06 +1000422 u64 new_tb_to_xs)
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000423{
424 unsigned temp_idx;
425 struct gettimeofday_vars *temp_varp;
426
427 temp_idx = (do_gtod.var_idx == 0);
428 temp_varp = &do_gtod.vars[temp_idx];
429
430 temp_varp->tb_to_xs = new_tb_to_xs;
431 temp_varp->tb_orig_stamp = new_tb_stamp;
432 temp_varp->stamp_xsec = new_stamp_xsec;
433 smp_mb();
434 do_gtod.varp = temp_varp;
435 do_gtod.var_idx = temp_idx;
436
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000437 /*
438 * tb_update_count is used to allow the userspace gettimeofday code
439 * to assure itself that it sees a consistent view of the tb_to_xs and
440 * stamp_xsec variables. It reads the tb_update_count, then reads
441 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
442 * the two values of tb_update_count match and are even then the
443 * tb_to_xs and stamp_xsec values are consistent. If not, then it
444 * loops back and reads them again until this criteria is met.
Paul Mackerras0a45d442006-03-15 13:47:15 +1100445 * We expect the caller to have done the first increment of
446 * vdso_data->tb_update_count already.
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000447 */
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100448 vdso_data->tb_orig_stamp = new_tb_stamp;
449 vdso_data->stamp_xsec = new_stamp_xsec;
450 vdso_data->tb_to_xs = new_tb_to_xs;
451 vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
452 vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000453 smp_wmb();
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100454 ++(vdso_data->tb_update_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455}
456
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457#ifdef CONFIG_SMP
458unsigned long profile_pc(struct pt_regs *regs)
459{
460 unsigned long pc = instruction_pointer(regs);
461
462 if (in_lock_functions(pc))
463 return regs->link;
464
465 return pc;
466}
467EXPORT_SYMBOL(profile_pc);
468#endif
469
470#ifdef CONFIG_PPC_ISERIES
471
472/*
473 * This function recalibrates the timebase based on the 49-bit time-of-day
474 * value in the Titan chip. The Titan is much more accurate than the value
475 * returned by the service processor for the timebase frequency.
476 */
477
Tony Breeds71712b42007-06-22 16:54:30 +1000478static int __init iSeries_tb_recal(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479{
480 struct div_result divres;
481 unsigned long titan, tb;
Tony Breeds71712b42007-06-22 16:54:30 +1000482
483 /* Make sure we only run on iSeries */
484 if (!firmware_has_feature(FW_FEATURE_ISERIES))
485 return -ENODEV;
486
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487 tb = get_tb();
488 titan = HvCallXm_loadTod();
489 if ( iSeries_recal_titan ) {
490 unsigned long tb_ticks = tb - iSeries_recal_tb;
491 unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12;
492 unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec;
493 unsigned long new_tb_ticks_per_jiffy = (new_tb_ticks_per_sec+(HZ/2))/HZ;
494 long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy;
495 char sign = '+';
496 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */
497 new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ;
498
499 if ( tick_diff < 0 ) {
500 tick_diff = -tick_diff;
501 sign = '-';
502 }
503 if ( tick_diff ) {
504 if ( tick_diff < tb_ticks_per_jiffy/25 ) {
505 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n",
506 new_tb_ticks_per_jiffy, sign, tick_diff );
507 tb_ticks_per_jiffy = new_tb_ticks_per_jiffy;
508 tb_ticks_per_sec = new_tb_ticks_per_sec;
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100509 calc_cputime_factors();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres );
511 do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
512 tb_to_xs = divres.result_low;
513 do_gtod.varp->tb_to_xs = tb_to_xs;
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100514 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
515 vdso_data->tb_to_xs = tb_to_xs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 }
517 else {
518 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n"
519 " new tb_ticks_per_jiffy = %lu\n"
520 " old tb_ticks_per_jiffy = %lu\n",
521 new_tb_ticks_per_jiffy, tb_ticks_per_jiffy );
522 }
523 }
524 }
525 iSeries_recal_titan = titan;
526 iSeries_recal_tb = tb;
Tony Breeds71712b42007-06-22 16:54:30 +1000527
Tony Breeds4a4cfe32007-09-22 07:35:52 +1000528 /* Called here as now we know accurate values for the timebase */
529 clocksource_init();
Tony Breeds71712b42007-06-22 16:54:30 +1000530 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531}
Tony Breeds71712b42007-06-22 16:54:30 +1000532late_initcall(iSeries_tb_recal);
533
534/* Called from platform early init */
535void __init iSeries_time_init_early(void)
536{
537 iSeries_recal_tb = get_tb();
538 iSeries_recal_titan = HvCallXm_loadTod();
539}
540#endif /* CONFIG_PPC_ISERIES */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541
542/*
543 * For iSeries shared processors, we have to let the hypervisor
544 * set the hardware decrementer. We set a virtual decrementer
545 * in the lppaca and call the hypervisor if the virtual
546 * decrementer is less than the current value in the hardware
547 * decrementer. (almost always the new decrementer value will
548 * be greater than the current hardware decementer so the hypervisor
549 * call will not be needed)
550 */
551
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552/*
553 * timer_interrupt - gets called when the decrementer overflows,
554 * with interrupts disabled.
555 */
Kumar Galac7aeffc2005-09-19 09:30:27 -0500556void timer_interrupt(struct pt_regs * regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557{
David Howells7d12e782006-10-05 14:55:46 +0100558 struct pt_regs *old_regs;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000559 int cpu = smp_processor_id();
Tony Breedsd831d0b2007-09-21 13:26:03 +1000560 struct clock_event_device *evt = &per_cpu(decrementers, cpu);
Paul Mackerrasd9680142007-10-09 09:59:17 +1000561 u64 now;
Tony Breedsd831d0b2007-09-21 13:26:03 +1000562
563 /* Ensure a positive value is written to the decrementer, or else
564 * some CPUs will continuue to take decrementer exceptions */
565 set_dec(DECREMENTER_MAX);
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000566
567#ifdef CONFIG_PPC32
568 if (atomic_read(&ppc_n_lost_interrupts) != 0)
569 do_IRQ(regs);
570#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571
Paul Mackerrasd9680142007-10-09 09:59:17 +1000572 now = get_tb_or_rtc();
573 if (now < per_cpu(decrementer_next_tb, cpu)) {
574 /* not time for this event yet */
575 now = per_cpu(decrementer_next_tb, cpu) - now;
576 if (now <= DECREMENTER_MAX)
Paul Mackerras43875cc2007-10-31 22:25:35 +1100577 set_dec((int)now);
Paul Mackerrasd9680142007-10-09 09:59:17 +1000578 return;
579 }
David Howells7d12e782006-10-05 14:55:46 +0100580 old_regs = set_irq_regs(regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 irq_enter();
582
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100583 calculate_steal_time();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000585#ifdef CONFIG_PPC_ISERIES
Stephen Rothwell501b6d22006-11-21 15:10:20 +1100586 if (firmware_has_feature(FW_FEATURE_ISERIES))
587 get_lppaca()->int_dword.fields.decr_int = 0;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000588#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589
Tony Breedsd831d0b2007-09-21 13:26:03 +1000590 if (evt->event_handler)
591 evt->event_handler(evt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592
593#ifdef CONFIG_PPC_ISERIES
Stephen Rothwell501b6d22006-11-21 15:10:20 +1100594 if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending())
Olaf Hering35a84c22006-10-07 22:08:26 +1000595 process_hvlpevents();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596#endif
597
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000598#ifdef CONFIG_PPC64
Stephen Rothwell8d15a3e2005-08-03 14:40:16 +1000599 /* collect purr register values often, for accurate calculations */
Stephen Rothwell1ababe12005-08-03 14:35:25 +1000600 if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
602 cu->current_tb = mfspr(SPRN_PURR);
603 }
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000604#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605
606 irq_exit();
David Howells7d12e782006-10-05 14:55:46 +0100607 set_irq_regs(old_regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608}
609
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000610void wakeup_decrementer(void)
611{
Paul Mackerras092b8f32006-02-20 10:38:56 +1100612 unsigned long ticks;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000613
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000614 /*
Paul Mackerras092b8f32006-02-20 10:38:56 +1100615 * The timebase gets saved on sleep and restored on wakeup,
616 * so all we need to do is to reset the decrementer.
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000617 */
Paul Mackerras092b8f32006-02-20 10:38:56 +1100618 ticks = tb_ticks_since(__get_cpu_var(last_jiffy));
619 if (ticks < tb_ticks_per_jiffy)
620 ticks = tb_ticks_per_jiffy - ticks;
621 else
622 ticks = 1;
623 set_dec(ticks);
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000624}
625
Paul Mackerrasa5b518e2005-10-22 14:55:23 +1000626#ifdef CONFIG_SMP
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000627void __init smp_space_timers(unsigned int max_cpus)
628{
629 int i;
Paul Mackerraseb36c282006-08-30 16:13:16 +1000630 u64 previous_tb = per_cpu(last_jiffy, boot_cpuid);
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000631
Paul Mackerrascbe62e22005-11-10 14:28:03 +1100632 /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */
633 previous_tb -= tb_ticks_per_jiffy;
will schmidte147ec82007-05-11 23:34:16 +1000634
KAMEZAWA Hiroyuki0e551952006-03-28 14:50:51 -0800635 for_each_possible_cpu(i) {
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100636 if (i == boot_cpuid)
637 continue;
will schmidte147ec82007-05-11 23:34:16 +1000638 per_cpu(last_jiffy, i) = previous_tb;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000639 }
640}
641#endif
642
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643/*
644 * Scheduler clock - returns current time in nanosec units.
645 *
646 * Note: mulhdu(a, b) (multiply high double unsigned) returns
647 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
648 * are 64-bit unsigned numbers.
649 */
650unsigned long long sched_clock(void)
651{
Paul Mackerras96c44502005-10-23 17:14:56 +1000652 if (__USE_RTC())
653 return get_rtc();
Tony Breedsfc9069fe2007-07-04 14:04:31 +1000654 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655}
656
Anton Blanchard0bb474a42006-06-20 18:47:26 +1000657static int __init get_freq(char *name, int cells, unsigned long *val)
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000658{
659 struct device_node *cpu;
Jeremy Kerra7f67bd2006-07-12 15:35:54 +1000660 const unsigned int *fp;
Anton Blanchard0bb474a42006-06-20 18:47:26 +1000661 int found = 0;
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000662
Anton Blanchard0bb474a42006-06-20 18:47:26 +1000663 /* The cpu node should have timebase and clock frequency properties */
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000664 cpu = of_find_node_by_type(NULL, "cpu");
665
Olaf Heringd8a81882006-02-04 10:34:56 +0100666 if (cpu) {
Stephen Rothwelle2eb6392007-04-03 22:26:41 +1000667 fp = of_get_property(cpu, name, NULL);
Olaf Heringd8a81882006-02-04 10:34:56 +0100668 if (fp) {
Anton Blanchard0bb474a42006-06-20 18:47:26 +1000669 found = 1;
Paul Mackerrasa4dc7ff2006-09-19 14:06:27 +1000670 *val = of_read_ulong(fp, cells);
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000671 }
Anton Blanchard0bb474a42006-06-20 18:47:26 +1000672
673 of_node_put(cpu);
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000674 }
Anton Blanchard0bb474a42006-06-20 18:47:26 +1000675
676 return found;
677}
678
679void __init generic_calibrate_decr(void)
680{
681 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */
682
683 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) &&
684 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) {
685
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000686 printk(KERN_ERR "WARNING: Estimating decrementer frequency "
687 "(not found)\n");
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000688 }
Anton Blanchard0bb474a42006-06-20 18:47:26 +1000689
690 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */
691
692 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) &&
693 !get_freq("clock-frequency", 1, &ppc_proc_freq)) {
694
695 printk(KERN_ERR "WARNING: Estimating processor frequency "
696 "(not found)\n");
697 }
698
Josh Boyeraab69292007-08-20 07:29:11 -0500699#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
Kumar Gala0fd6f712005-10-25 23:02:59 -0500700 /* Set the time base to zero */
701 mtspr(SPRN_TBWL, 0);
702 mtspr(SPRN_TBWU, 0);
703
704 /* Clear any pending timer interrupts */
705 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS);
706
707 /* Enable decrementer interrupt */
708 mtspr(SPRN_TCR, TCR_DIE);
709#endif
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000710}
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000711
Tony Breedsaa3be5f2007-09-21 13:26:02 +1000712int update_persistent_clock(struct timespec now)
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000713{
714 struct rtc_time tm;
715
Tony Breedsaa3be5f2007-09-21 13:26:02 +1000716 if (!ppc_md.set_rtc_time)
717 return 0;
718
719 to_tm(now.tv_sec + 1 + timezone_offset, &tm);
720 tm.tm_year -= 1900;
721 tm.tm_mon -= 1;
722
723 return ppc_md.set_rtc_time(&tm);
724}
725
726unsigned long read_persistent_clock(void)
727{
728 struct rtc_time tm;
729 static int first = 1;
730
731 /* XXX this is a litle fragile but will work okay in the short term */
732 if (first) {
733 first = 0;
734 if (ppc_md.time_init)
735 timezone_offset = ppc_md.time_init();
736
737 /* get_boot_time() isn't guaranteed to be safe to call late */
738 if (ppc_md.get_boot_time)
739 return ppc_md.get_boot_time() -timezone_offset;
740 }
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000741 if (!ppc_md.get_rtc_time)
742 return 0;
743 ppc_md.get_rtc_time(&tm);
744 return mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
745 tm.tm_hour, tm.tm_min, tm.tm_sec);
746}
747
Tony Breeds4a4cfe32007-09-22 07:35:52 +1000748/* clocksource code */
749static cycle_t rtc_read(void)
750{
751 return (cycle_t)get_rtc();
752}
753
754static cycle_t timebase_read(void)
755{
756 return (cycle_t)get_tb();
757}
758
759void update_vsyscall(struct timespec *wall_time, struct clocksource *clock)
760{
761 u64 t2x, stamp_xsec;
762
763 if (clock != &clocksource_timebase)
764 return;
765
766 /* Make userspace gettimeofday spin until we're done. */
767 ++vdso_data->tb_update_count;
768 smp_mb();
769
770 /* XXX this assumes clock->shift == 22 */
771 /* 4611686018 ~= 2^(20+64-22) / 1e9 */
772 t2x = (u64) clock->mult * 4611686018ULL;
773 stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC;
774 do_div(stamp_xsec, 1000000000);
775 stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC;
776 update_gtod(clock->cycle_last, stamp_xsec, t2x);
777}
778
779void update_vsyscall_tz(void)
780{
781 /* Make userspace gettimeofday spin until we're done. */
782 ++vdso_data->tb_update_count;
783 smp_mb();
784 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
785 vdso_data->tz_dsttime = sys_tz.tz_dsttime;
786 smp_mb();
787 ++vdso_data->tb_update_count;
788}
789
790void __init clocksource_init(void)
791{
792 struct clocksource *clock;
793
794 if (__USE_RTC())
795 clock = &clocksource_rtc;
796 else
797 clock = &clocksource_timebase;
798
799 clock->mult = clocksource_hz2mult(tb_ticks_per_sec, clock->shift);
800
801 if (clocksource_register(clock)) {
802 printk(KERN_ERR "clocksource: %s is already registered\n",
803 clock->name);
804 return;
805 }
806
807 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n",
808 clock->name, clock->mult, clock->shift);
809}
810
Tony Breedsd831d0b2007-09-21 13:26:03 +1000811static int decrementer_set_next_event(unsigned long evt,
812 struct clock_event_device *dev)
813{
Paul Mackerrasd9680142007-10-09 09:59:17 +1000814 __get_cpu_var(decrementer_next_tb) = get_tb_or_rtc() + evt;
Tony Breedsd831d0b2007-09-21 13:26:03 +1000815 set_dec(evt);
816 return 0;
817}
818
819static void decrementer_set_mode(enum clock_event_mode mode,
820 struct clock_event_device *dev)
821{
822 if (mode != CLOCK_EVT_MODE_ONESHOT)
823 decrementer_set_next_event(DECREMENTER_MAX, dev);
824}
825
826static void register_decrementer_clockevent(int cpu)
827{
828 struct clock_event_device *dec = &per_cpu(decrementers, cpu);
829
830 *dec = decrementer_clockevent;
831 dec->cpumask = cpumask_of_cpu(cpu);
832
Tony Breeds0302f122007-11-12 14:25:50 +1100833 printk(KERN_DEBUG "clockevent: %s mult[%lx] shift[%d] cpu[%d]\n",
Tony Breedsd831d0b2007-09-21 13:26:03 +1000834 dec->name, dec->mult, dec->shift, cpu);
835
836 clockevents_register_device(dec);
837}
838
839void init_decrementer_clockevent(void)
840{
841 int cpu = smp_processor_id();
842
843 decrementer_clockevent.mult = div_sc(ppc_tb_freq, NSEC_PER_SEC,
844 decrementer_clockevent.shift);
845 decrementer_clockevent.max_delta_ns =
846 clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent);
Paul Mackerras43875cc2007-10-31 22:25:35 +1100847 decrementer_clockevent.min_delta_ns =
848 clockevent_delta2ns(2, &decrementer_clockevent);
Tony Breedsd831d0b2007-09-21 13:26:03 +1000849
850 register_decrementer_clockevent(cpu);
851}
852
853void secondary_cpu_time_init(void)
854{
855 /* FIME: Should make unrelatred change to move snapshot_timebase
856 * call here ! */
857 register_decrementer_clockevent(smp_processor_id());
858}
859
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000860/* This function is only called on the boot processor */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861void __init time_init(void)
862{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 struct div_result res;
Paul Mackerras092b8f32006-02-20 10:38:56 +1100865 u64 scale, x;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000866 unsigned shift;
867
Paul Mackerras96c44502005-10-23 17:14:56 +1000868 if (__USE_RTC()) {
869 /* 601 processor: dec counts down by 128 every 128ns */
870 ppc_tb_freq = 1000000000;
Paul Mackerraseb36c282006-08-30 16:13:16 +1000871 tb_last_jiffy = get_rtcl();
Paul Mackerras96c44502005-10-23 17:14:56 +1000872 } else {
873 /* Normal PowerPC with timebase register */
874 ppc_md.calibrate_decr();
Olof Johansson224ad802006-04-12 15:20:27 -0500875 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n",
Paul Mackerras96c44502005-10-23 17:14:56 +1000876 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
Olof Johansson224ad802006-04-12 15:20:27 -0500877 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n",
Paul Mackerras96c44502005-10-23 17:14:56 +1000878 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
Paul Mackerraseb36c282006-08-30 16:13:16 +1000879 tb_last_jiffy = get_tb();
Paul Mackerras96c44502005-10-23 17:14:56 +1000880 }
Paul Mackerras374e99d2005-10-20 21:04:51 +1000881
882 tb_ticks_per_jiffy = ppc_tb_freq / HZ;
Paul Mackerras092b8f32006-02-20 10:38:56 +1100883 tb_ticks_per_sec = ppc_tb_freq;
Paul Mackerras374e99d2005-10-20 21:04:51 +1000884 tb_ticks_per_usec = ppc_tb_freq / 1000000;
885 tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000);
Paul Mackerrasc6622f62006-02-24 10:06:59 +1100886 calc_cputime_factors();
Paul Mackerras092b8f32006-02-20 10:38:56 +1100887
888 /*
889 * Calculate the length of each tick in ns. It will not be
890 * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ.
891 * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq,
892 * rounded up.
893 */
894 x = (u64) NSEC_PER_SEC * tb_ticks_per_jiffy + ppc_tb_freq - 1;
895 do_div(x, ppc_tb_freq);
896 tick_nsec = x;
897 last_tick_len = x << TICKLEN_SCALE;
898
899 /*
900 * Compute ticklen_to_xs, which is a factor which gets multiplied
901 * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value.
902 * It is computed as:
903 * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9)
904 * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT
Paul Mackerras0a45d442006-03-15 13:47:15 +1100905 * which turns out to be N = 51 - SHIFT_HZ.
906 * This gives the result as a 0.64 fixed-point fraction.
907 * That value is reduced by an offset amounting to 1 xsec per
908 * 2^31 timebase ticks to avoid problems with time going backwards
909 * by 1 xsec when we do timer_recalc_offset due to losing the
910 * fractional xsec. That offset is equal to ppc_tb_freq/2^51
911 * since there are 2^20 xsec in a second.
Paul Mackerras092b8f32006-02-20 10:38:56 +1100912 */
Paul Mackerras0a45d442006-03-15 13:47:15 +1100913 div128_by_32((1ULL << 51) - ppc_tb_freq, 0,
914 tb_ticks_per_jiffy << SHIFT_HZ, &res);
Paul Mackerras092b8f32006-02-20 10:38:56 +1100915 div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res);
916 ticklen_to_xs = res.result_low;
917
918 /* Compute tb_to_xs from tick_nsec */
919 tb_to_xs = mulhdu(last_tick_len << TICKLEN_SHIFT, ticklen_to_xs);
Paul Mackerras374e99d2005-10-20 21:04:51 +1000920
Linus Torvalds1da177e2005-04-16 15:20:36 -0700921 /*
922 * Compute scale factor for sched_clock.
923 * The calibrate_decr() function has set tb_ticks_per_sec,
924 * which is the timebase frequency.
925 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
926 * the 128-bit result as a 64.64 fixed-point number.
927 * We then shift that number right until it is less than 1.0,
928 * giving us the scale factor and shift count to use in
929 * sched_clock().
930 */
931 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res);
932 scale = res.result_low;
933 for (shift = 0; res.result_high != 0; ++shift) {
934 scale = (scale >> 1) | (res.result_high << 63);
935 res.result_high >>= 1;
936 }
937 tb_to_ns_scale = scale;
938 tb_to_ns_shift = shift;
Tony Breedsfc9069fe2007-07-04 14:04:31 +1000939 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
Benjamin Herrenschmidtc27da3392007-09-19 14:21:56 +1000940 boot_tb = get_tb_or_rtc();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942 write_seqlock_irqsave(&xtime_lock, flags);
Paul Mackerras092b8f32006-02-20 10:38:56 +1100943
944 /* If platform provided a timezone (pmac), we correct the time */
945 if (timezone_offset) {
946 sys_tz.tz_minuteswest = -timezone_offset / 60;
947 sys_tz.tz_dsttime = 0;
Paul Mackerras092b8f32006-02-20 10:38:56 +1100948 }
949
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950 do_gtod.varp = &do_gtod.vars[0];
951 do_gtod.var_idx = 0;
Paul Mackerras96c44502005-10-23 17:14:56 +1000952 do_gtod.varp->tb_orig_stamp = tb_last_jiffy;
Paul Mackerraseb36c282006-08-30 16:13:16 +1000953 __get_cpu_var(last_jiffy) = tb_last_jiffy;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000954 do_gtod.varp->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955 do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
956 do_gtod.varp->tb_to_xs = tb_to_xs;
957 do_gtod.tb_to_us = tb_to_us;
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100958
959 vdso_data->tb_orig_stamp = tb_last_jiffy;
960 vdso_data->tb_update_count = 0;
961 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
Paul Mackerras092b8f32006-02-20 10:38:56 +1100962 vdso_data->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC;
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100963 vdso_data->tb_to_xs = tb_to_xs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964
965 time_freq = 0;
966
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967 write_sequnlock_irqrestore(&xtime_lock, flags);
968
Tony Breeds4a4cfe32007-09-22 07:35:52 +1000969 /* Register the clocksource, if we're not running on iSeries */
970 if (!firmware_has_feature(FW_FEATURE_ISERIES))
971 clocksource_init();
972
Tony Breedsd831d0b2007-09-21 13:26:03 +1000973 init_decrementer_clockevent();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700974}
975
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977#define FEBRUARY 2
978#define STARTOFTIME 1970
979#define SECDAY 86400L
980#define SECYR (SECDAY * 365)
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000981#define leapyear(year) ((year) % 4 == 0 && \
982 ((year) % 100 != 0 || (year) % 400 == 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983#define days_in_year(a) (leapyear(a) ? 366 : 365)
984#define days_in_month(a) (month_days[(a) - 1])
985
986static int month_days[12] = {
987 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
988};
989
990/*
991 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
992 */
993void GregorianDay(struct rtc_time * tm)
994{
995 int leapsToDate;
996 int lastYear;
997 int day;
998 int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
999
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001000 lastYear = tm->tm_year - 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001
1002 /*
1003 * Number of leap corrections to apply up to end of last year
1004 */
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001005 leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001006
1007 /*
1008 * This year is a leap year if it is divisible by 4 except when it is
1009 * divisible by 100 unless it is divisible by 400
1010 *
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001011 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012 */
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001013 day = tm->tm_mon > 2 && leapyear(tm->tm_year);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014
1015 day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] +
1016 tm->tm_mday;
1017
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001018 tm->tm_wday = day % 7;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019}
1020
1021void to_tm(int tim, struct rtc_time * tm)
1022{
1023 register int i;
1024 register long hms, day;
1025
1026 day = tim / SECDAY;
1027 hms = tim % SECDAY;
1028
1029 /* Hours, minutes, seconds are easy */
1030 tm->tm_hour = hms / 3600;
1031 tm->tm_min = (hms % 3600) / 60;
1032 tm->tm_sec = (hms % 3600) % 60;
1033
1034 /* Number of years in days */
1035 for (i = STARTOFTIME; day >= days_in_year(i); i++)
1036 day -= days_in_year(i);
1037 tm->tm_year = i;
1038
1039 /* Number of months in days left */
1040 if (leapyear(tm->tm_year))
1041 days_in_month(FEBRUARY) = 29;
1042 for (i = 1; day >= days_in_month(i); i++)
1043 day -= days_in_month(i);
1044 days_in_month(FEBRUARY) = 28;
1045 tm->tm_mon = i;
1046
1047 /* Days are what is left over (+1) from all that. */
1048 tm->tm_mday = day + 1;
1049
1050 /*
1051 * Determine the day of week
1052 */
1053 GregorianDay(tm);
1054}
1055
1056/* Auxiliary function to compute scaling factors */
1057/* Actually the choice of a timebase running at 1/4 the of the bus
1058 * frequency giving resolution of a few tens of nanoseconds is quite nice.
1059 * It makes this computation very precise (27-28 bits typically) which
1060 * is optimistic considering the stability of most processor clock
1061 * oscillators and the precision with which the timebase frequency
1062 * is measured but does not harm.
1063 */
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001064unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale)
1065{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001066 unsigned mlt=0, tmp, err;
1067 /* No concern for performance, it's done once: use a stupid
1068 * but safe and compact method to find the multiplier.
1069 */
1070
1071 for (tmp = 1U<<31; tmp != 0; tmp >>= 1) {
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001072 if (mulhwu(inscale, mlt|tmp) < outscale)
1073 mlt |= tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 }
1075
1076 /* We might still be off by 1 for the best approximation.
1077 * A side effect of this is that if outscale is too large
1078 * the returned value will be zero.
1079 * Many corner cases have been checked and seem to work,
1080 * some might have been forgotten in the test however.
1081 */
1082
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001083 err = inscale * (mlt+1);
1084 if (err <= inscale/2)
1085 mlt++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086 return mlt;
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001087}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088
1089/*
1090 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1091 * result.
1092 */
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001093void div128_by_32(u64 dividend_high, u64 dividend_low,
1094 unsigned divisor, struct div_result *dr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001095{
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001096 unsigned long a, b, c, d;
1097 unsigned long w, x, y, z;
1098 u64 ra, rb, rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099
1100 a = dividend_high >> 32;
1101 b = dividend_high & 0xffffffff;
1102 c = dividend_low >> 32;
1103 d = dividend_low & 0xffffffff;
1104
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001105 w = a / divisor;
1106 ra = ((u64)(a - (w * divisor)) << 32) + b;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001108 rb = ((u64) do_div(ra, divisor) << 32) + c;
1109 x = ra;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001110
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001111 rc = ((u64) do_div(rb, divisor) << 32) + d;
1112 y = rb;
1113
1114 do_div(rc, divisor);
1115 z = rc;
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001116
1117 dr->result_high = ((u64)w << 32) + x;
1118 dr->result_low = ((u64)y << 32) + z;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119
1120}