Commit | Line | Data |
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1da177e4 | 1 | /* |
1da177e4 LT |
2 | * 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 | ||
35 | #include <linux/config.h> | |
36 | #include <linux/errno.h> | |
37 | #include <linux/module.h> | |
38 | #include <linux/sched.h> | |
39 | #include <linux/kernel.h> | |
40 | #include <linux/param.h> | |
41 | #include <linux/string.h> | |
42 | #include <linux/mm.h> | |
43 | #include <linux/interrupt.h> | |
44 | #include <linux/timex.h> | |
45 | #include <linux/kernel_stat.h> | |
1da177e4 LT |
46 | #include <linux/time.h> |
47 | #include <linux/init.h> | |
48 | #include <linux/profile.h> | |
49 | #include <linux/cpu.h> | |
50 | #include <linux/security.h> | |
f2783c15 PM |
51 | #include <linux/percpu.h> |
52 | #include <linux/rtc.h> | |
092b8f34 | 53 | #include <linux/jiffies.h> |
c6622f63 | 54 | #include <linux/posix-timers.h> |
1da177e4 | 55 | |
1da177e4 LT |
56 | #include <asm/io.h> |
57 | #include <asm/processor.h> | |
58 | #include <asm/nvram.h> | |
59 | #include <asm/cache.h> | |
60 | #include <asm/machdep.h> | |
1da177e4 LT |
61 | #include <asm/uaccess.h> |
62 | #include <asm/time.h> | |
1da177e4 | 63 | #include <asm/prom.h> |
f2783c15 PM |
64 | #include <asm/irq.h> |
65 | #include <asm/div64.h> | |
2249ca9d | 66 | #include <asm/smp.h> |
a7f290da | 67 | #include <asm/vdso_datapage.h> |
f2783c15 | 68 | #ifdef CONFIG_PPC64 |
1ababe11 | 69 | #include <asm/firmware.h> |
f2783c15 PM |
70 | #endif |
71 | #ifdef CONFIG_PPC_ISERIES | |
8875ccfb | 72 | #include <asm/iseries/it_lp_queue.h> |
8021b8a7 | 73 | #include <asm/iseries/hv_call_xm.h> |
f2783c15 | 74 | #endif |
732ee21f | 75 | #include <asm/smp.h> |
1da177e4 | 76 | |
1da177e4 LT |
77 | /* keep track of when we need to update the rtc */ |
78 | time_t last_rtc_update; | |
1da177e4 LT |
79 | #ifdef CONFIG_PPC_ISERIES |
80 | unsigned long iSeries_recal_titan = 0; | |
81 | unsigned long iSeries_recal_tb = 0; | |
82 | static unsigned long first_settimeofday = 1; | |
83 | #endif | |
84 | ||
f2783c15 PM |
85 | /* The decrementer counts down by 128 every 128ns on a 601. */ |
86 | #define DECREMENTER_COUNT_601 (1000000000 / HZ) | |
87 | ||
1da177e4 LT |
88 | #define XSEC_PER_SEC (1024*1024) |
89 | ||
f2783c15 PM |
90 | #ifdef CONFIG_PPC64 |
91 | #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) | |
92 | #else | |
93 | /* compute ((xsec << 12) * max) >> 32 */ | |
94 | #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) | |
95 | #endif | |
96 | ||
1da177e4 LT |
97 | unsigned long tb_ticks_per_jiffy; |
98 | unsigned long tb_ticks_per_usec = 100; /* sane default */ | |
99 | EXPORT_SYMBOL(tb_ticks_per_usec); | |
100 | unsigned long tb_ticks_per_sec; | |
2cf82c02 | 101 | EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ |
f2783c15 PM |
102 | u64 tb_to_xs; |
103 | unsigned tb_to_us; | |
092b8f34 PM |
104 | |
105 | #define TICKLEN_SCALE (SHIFT_SCALE - 10) | |
106 | u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */ | |
107 | u64 ticklen_to_xs; /* 0.64 fraction */ | |
108 | ||
109 | /* If last_tick_len corresponds to about 1/HZ seconds, then | |
110 | last_tick_len << TICKLEN_SHIFT will be about 2^63. */ | |
111 | #define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ) | |
112 | ||
1da177e4 | 113 | DEFINE_SPINLOCK(rtc_lock); |
6ae3db11 | 114 | EXPORT_SYMBOL_GPL(rtc_lock); |
1da177e4 | 115 | |
f2783c15 PM |
116 | u64 tb_to_ns_scale; |
117 | unsigned tb_to_ns_shift; | |
1da177e4 LT |
118 | |
119 | struct gettimeofday_struct do_gtod; | |
120 | ||
121 | extern unsigned long wall_jiffies; | |
1da177e4 LT |
122 | |
123 | extern struct timezone sys_tz; | |
f2783c15 | 124 | static long timezone_offset; |
1da177e4 | 125 | |
10f7e7c1 AB |
126 | unsigned long ppc_proc_freq; |
127 | unsigned long ppc_tb_freq; | |
128 | ||
96c44507 PM |
129 | u64 tb_last_jiffy __cacheline_aligned_in_smp; |
130 | unsigned long tb_last_stamp; | |
131 | ||
132 | /* | |
133 | * Note that on ppc32 this only stores the bottom 32 bits of | |
134 | * the timebase value, but that's enough to tell when a jiffy | |
135 | * has passed. | |
136 | */ | |
137 | DEFINE_PER_CPU(unsigned long, last_jiffy); | |
138 | ||
c6622f63 PM |
139 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING |
140 | /* | |
141 | * Factors for converting from cputime_t (timebase ticks) to | |
142 | * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds). | |
143 | * These are all stored as 0.64 fixed-point binary fractions. | |
144 | */ | |
145 | u64 __cputime_jiffies_factor; | |
2cf82c02 | 146 | EXPORT_SYMBOL(__cputime_jiffies_factor); |
c6622f63 | 147 | u64 __cputime_msec_factor; |
2cf82c02 | 148 | EXPORT_SYMBOL(__cputime_msec_factor); |
c6622f63 | 149 | u64 __cputime_sec_factor; |
2cf82c02 | 150 | EXPORT_SYMBOL(__cputime_sec_factor); |
c6622f63 | 151 | u64 __cputime_clockt_factor; |
2cf82c02 | 152 | EXPORT_SYMBOL(__cputime_clockt_factor); |
c6622f63 PM |
153 | |
154 | static void calc_cputime_factors(void) | |
155 | { | |
156 | struct div_result res; | |
157 | ||
158 | div128_by_32(HZ, 0, tb_ticks_per_sec, &res); | |
159 | __cputime_jiffies_factor = res.result_low; | |
160 | div128_by_32(1000, 0, tb_ticks_per_sec, &res); | |
161 | __cputime_msec_factor = res.result_low; | |
162 | div128_by_32(1, 0, tb_ticks_per_sec, &res); | |
163 | __cputime_sec_factor = res.result_low; | |
164 | div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); | |
165 | __cputime_clockt_factor = res.result_low; | |
166 | } | |
167 | ||
168 | /* | |
169 | * Read the PURR on systems that have it, otherwise the timebase. | |
170 | */ | |
171 | static u64 read_purr(void) | |
172 | { | |
173 | if (cpu_has_feature(CPU_FTR_PURR)) | |
174 | return mfspr(SPRN_PURR); | |
175 | return mftb(); | |
176 | } | |
177 | ||
178 | /* | |
179 | * Account time for a transition between system, hard irq | |
180 | * or soft irq state. | |
181 | */ | |
182 | void account_system_vtime(struct task_struct *tsk) | |
183 | { | |
184 | u64 now, delta; | |
185 | unsigned long flags; | |
186 | ||
187 | local_irq_save(flags); | |
188 | now = read_purr(); | |
189 | delta = now - get_paca()->startpurr; | |
190 | get_paca()->startpurr = now; | |
191 | if (!in_interrupt()) { | |
192 | delta += get_paca()->system_time; | |
193 | get_paca()->system_time = 0; | |
194 | } | |
195 | account_system_time(tsk, 0, delta); | |
196 | local_irq_restore(flags); | |
197 | } | |
198 | ||
199 | /* | |
200 | * Transfer the user and system times accumulated in the paca | |
201 | * by the exception entry and exit code to the generic process | |
202 | * user and system time records. | |
203 | * Must be called with interrupts disabled. | |
204 | */ | |
205 | void account_process_vtime(struct task_struct *tsk) | |
206 | { | |
207 | cputime_t utime; | |
208 | ||
209 | utime = get_paca()->user_time; | |
210 | get_paca()->user_time = 0; | |
211 | account_user_time(tsk, utime); | |
212 | } | |
213 | ||
214 | static void account_process_time(struct pt_regs *regs) | |
215 | { | |
216 | int cpu = smp_processor_id(); | |
217 | ||
218 | account_process_vtime(current); | |
219 | run_local_timers(); | |
220 | if (rcu_pending(cpu)) | |
221 | rcu_check_callbacks(cpu, user_mode(regs)); | |
222 | scheduler_tick(); | |
223 | run_posix_cpu_timers(current); | |
224 | } | |
225 | ||
226 | #ifdef CONFIG_PPC_SPLPAR | |
227 | /* | |
228 | * Stuff for accounting stolen time. | |
229 | */ | |
230 | struct cpu_purr_data { | |
231 | int initialized; /* thread is running */ | |
232 | u64 tb0; /* timebase at origin time */ | |
233 | u64 purr0; /* PURR at origin time */ | |
234 | u64 tb; /* last TB value read */ | |
235 | u64 purr; /* last PURR value read */ | |
236 | u64 stolen; /* stolen time so far */ | |
237 | spinlock_t lock; | |
238 | }; | |
239 | ||
240 | static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data); | |
241 | ||
242 | static void snapshot_tb_and_purr(void *data) | |
243 | { | |
244 | struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data); | |
245 | ||
246 | p->tb0 = mftb(); | |
247 | p->purr0 = mfspr(SPRN_PURR); | |
248 | p->tb = p->tb0; | |
249 | p->purr = 0; | |
250 | wmb(); | |
251 | p->initialized = 1; | |
252 | } | |
253 | ||
254 | /* | |
255 | * Called during boot when all cpus have come up. | |
256 | */ | |
257 | void snapshot_timebases(void) | |
258 | { | |
259 | int cpu; | |
260 | ||
261 | if (!cpu_has_feature(CPU_FTR_PURR)) | |
262 | return; | |
0e551954 | 263 | for_each_possible_cpu(cpu) |
c6622f63 PM |
264 | spin_lock_init(&per_cpu(cpu_purr_data, cpu).lock); |
265 | on_each_cpu(snapshot_tb_and_purr, NULL, 0, 1); | |
266 | } | |
267 | ||
268 | void calculate_steal_time(void) | |
269 | { | |
270 | u64 tb, purr, t0; | |
271 | s64 stolen; | |
272 | struct cpu_purr_data *p0, *pme, *phim; | |
273 | int cpu; | |
274 | ||
275 | if (!cpu_has_feature(CPU_FTR_PURR)) | |
276 | return; | |
277 | cpu = smp_processor_id(); | |
278 | pme = &per_cpu(cpu_purr_data, cpu); | |
279 | if (!pme->initialized) | |
280 | return; /* this can happen in early boot */ | |
281 | p0 = &per_cpu(cpu_purr_data, cpu & ~1); | |
282 | phim = &per_cpu(cpu_purr_data, cpu ^ 1); | |
283 | spin_lock(&p0->lock); | |
284 | tb = mftb(); | |
285 | purr = mfspr(SPRN_PURR) - pme->purr0; | |
286 | if (!phim->initialized || !cpu_online(cpu ^ 1)) { | |
287 | stolen = (tb - pme->tb) - (purr - pme->purr); | |
288 | } else { | |
289 | t0 = pme->tb0; | |
290 | if (phim->tb0 < t0) | |
291 | t0 = phim->tb0; | |
292 | stolen = phim->tb - t0 - phim->purr - purr - p0->stolen; | |
293 | } | |
294 | if (stolen > 0) { | |
295 | account_steal_time(current, stolen); | |
296 | p0->stolen += stolen; | |
297 | } | |
298 | pme->tb = tb; | |
299 | pme->purr = purr; | |
300 | spin_unlock(&p0->lock); | |
301 | } | |
302 | ||
303 | /* | |
304 | * Must be called before the cpu is added to the online map when | |
305 | * a cpu is being brought up at runtime. | |
306 | */ | |
307 | static void snapshot_purr(void) | |
308 | { | |
309 | int cpu; | |
310 | u64 purr; | |
311 | struct cpu_purr_data *p0, *pme, *phim; | |
312 | unsigned long flags; | |
313 | ||
314 | if (!cpu_has_feature(CPU_FTR_PURR)) | |
315 | return; | |
316 | cpu = smp_processor_id(); | |
317 | pme = &per_cpu(cpu_purr_data, cpu); | |
318 | p0 = &per_cpu(cpu_purr_data, cpu & ~1); | |
319 | phim = &per_cpu(cpu_purr_data, cpu ^ 1); | |
320 | spin_lock_irqsave(&p0->lock, flags); | |
321 | pme->tb = pme->tb0 = mftb(); | |
322 | purr = mfspr(SPRN_PURR); | |
323 | if (!phim->initialized) { | |
324 | pme->purr = 0; | |
325 | pme->purr0 = purr; | |
326 | } else { | |
327 | /* set p->purr and p->purr0 for no change in p0->stolen */ | |
328 | pme->purr = phim->tb - phim->tb0 - phim->purr - p0->stolen; | |
329 | pme->purr0 = purr - pme->purr; | |
330 | } | |
331 | pme->initialized = 1; | |
332 | spin_unlock_irqrestore(&p0->lock, flags); | |
333 | } | |
334 | ||
335 | #endif /* CONFIG_PPC_SPLPAR */ | |
336 | ||
337 | #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */ | |
338 | #define calc_cputime_factors() | |
339 | #define account_process_time(regs) update_process_times(user_mode(regs)) | |
340 | #define calculate_steal_time() do { } while (0) | |
341 | #endif | |
342 | ||
343 | #if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR)) | |
344 | #define snapshot_purr() do { } while (0) | |
345 | #endif | |
346 | ||
347 | /* | |
348 | * Called when a cpu comes up after the system has finished booting, | |
349 | * i.e. as a result of a hotplug cpu action. | |
350 | */ | |
351 | void snapshot_timebase(void) | |
352 | { | |
353 | __get_cpu_var(last_jiffy) = get_tb(); | |
354 | snapshot_purr(); | |
355 | } | |
356 | ||
6defa38b PM |
357 | void __delay(unsigned long loops) |
358 | { | |
359 | unsigned long start; | |
360 | int diff; | |
361 | ||
362 | if (__USE_RTC()) { | |
363 | start = get_rtcl(); | |
364 | do { | |
365 | /* the RTCL register wraps at 1000000000 */ | |
366 | diff = get_rtcl() - start; | |
367 | if (diff < 0) | |
368 | diff += 1000000000; | |
369 | } while (diff < loops); | |
370 | } else { | |
371 | start = get_tbl(); | |
372 | while (get_tbl() - start < loops) | |
373 | HMT_low(); | |
374 | HMT_medium(); | |
375 | } | |
376 | } | |
377 | EXPORT_SYMBOL(__delay); | |
378 | ||
379 | void udelay(unsigned long usecs) | |
380 | { | |
381 | __delay(tb_ticks_per_usec * usecs); | |
382 | } | |
383 | EXPORT_SYMBOL(udelay); | |
384 | ||
1da177e4 LT |
385 | static __inline__ void timer_check_rtc(void) |
386 | { | |
387 | /* | |
388 | * update the rtc when needed, this should be performed on the | |
389 | * right fraction of a second. Half or full second ? | |
390 | * Full second works on mk48t59 clocks, others need testing. | |
391 | * Note that this update is basically only used through | |
392 | * the adjtimex system calls. Setting the HW clock in | |
393 | * any other way is a /dev/rtc and userland business. | |
394 | * This is still wrong by -0.5/+1.5 jiffies because of the | |
395 | * timer interrupt resolution and possible delay, but here we | |
396 | * hit a quantization limit which can only be solved by higher | |
397 | * resolution timers and decoupling time management from timer | |
398 | * interrupts. This is also wrong on the clocks | |
399 | * which require being written at the half second boundary. | |
400 | * We should have an rtc call that only sets the minutes and | |
401 | * seconds like on Intel to avoid problems with non UTC clocks. | |
402 | */ | |
d2e61512 | 403 | if (ppc_md.set_rtc_time && ntp_synced() && |
f2783c15 | 404 | xtime.tv_sec - last_rtc_update >= 659 && |
092b8f34 | 405 | abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ) { |
f2783c15 PM |
406 | struct rtc_time tm; |
407 | to_tm(xtime.tv_sec + 1 + timezone_offset, &tm); | |
408 | tm.tm_year -= 1900; | |
409 | tm.tm_mon -= 1; | |
410 | if (ppc_md.set_rtc_time(&tm) == 0) | |
411 | last_rtc_update = xtime.tv_sec + 1; | |
412 | else | |
413 | /* Try again one minute later */ | |
414 | last_rtc_update += 60; | |
1da177e4 LT |
415 | } |
416 | } | |
417 | ||
418 | /* | |
419 | * This version of gettimeofday has microsecond resolution. | |
420 | */ | |
f2783c15 | 421 | static inline void __do_gettimeofday(struct timeval *tv, u64 tb_val) |
1da177e4 | 422 | { |
f2783c15 PM |
423 | unsigned long sec, usec; |
424 | u64 tb_ticks, xsec; | |
425 | struct gettimeofday_vars *temp_varp; | |
426 | u64 temp_tb_to_xs, temp_stamp_xsec; | |
1da177e4 LT |
427 | |
428 | /* | |
429 | * These calculations are faster (gets rid of divides) | |
430 | * if done in units of 1/2^20 rather than microseconds. | |
431 | * The conversion to microseconds at the end is done | |
432 | * without a divide (and in fact, without a multiply) | |
433 | */ | |
434 | temp_varp = do_gtod.varp; | |
435 | tb_ticks = tb_val - temp_varp->tb_orig_stamp; | |
436 | temp_tb_to_xs = temp_varp->tb_to_xs; | |
437 | temp_stamp_xsec = temp_varp->stamp_xsec; | |
f2783c15 | 438 | xsec = temp_stamp_xsec + mulhdu(tb_ticks, temp_tb_to_xs); |
1da177e4 | 439 | sec = xsec / XSEC_PER_SEC; |
f2783c15 PM |
440 | usec = (unsigned long)xsec & (XSEC_PER_SEC - 1); |
441 | usec = SCALE_XSEC(usec, 1000000); | |
1da177e4 LT |
442 | |
443 | tv->tv_sec = sec; | |
444 | tv->tv_usec = usec; | |
445 | } | |
446 | ||
447 | void do_gettimeofday(struct timeval *tv) | |
448 | { | |
96c44507 PM |
449 | if (__USE_RTC()) { |
450 | /* do this the old way */ | |
451 | unsigned long flags, seq; | |
092b8f34 | 452 | unsigned int sec, nsec, usec; |
96c44507 PM |
453 | |
454 | do { | |
455 | seq = read_seqbegin_irqsave(&xtime_lock, flags); | |
456 | sec = xtime.tv_sec; | |
457 | nsec = xtime.tv_nsec + tb_ticks_since(tb_last_stamp); | |
96c44507 | 458 | } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); |
092b8f34 | 459 | usec = nsec / 1000; |
96c44507 PM |
460 | while (usec >= 1000000) { |
461 | usec -= 1000000; | |
462 | ++sec; | |
463 | } | |
464 | tv->tv_sec = sec; | |
465 | tv->tv_usec = usec; | |
466 | return; | |
467 | } | |
1da177e4 LT |
468 | __do_gettimeofday(tv, get_tb()); |
469 | } | |
470 | ||
471 | EXPORT_SYMBOL(do_gettimeofday); | |
472 | ||
1da177e4 | 473 | /* |
f2783c15 PM |
474 | * There are two copies of tb_to_xs and stamp_xsec so that no |
475 | * lock is needed to access and use these values in | |
476 | * do_gettimeofday. We alternate the copies and as long as a | |
477 | * reasonable time elapses between changes, there will never | |
478 | * be inconsistent values. ntpd has a minimum of one minute | |
479 | * between updates. | |
1da177e4 | 480 | */ |
f2783c15 | 481 | static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec, |
5d14a18d | 482 | u64 new_tb_to_xs) |
1da177e4 | 483 | { |
1da177e4 | 484 | unsigned temp_idx; |
f2783c15 | 485 | struct gettimeofday_vars *temp_varp; |
1da177e4 LT |
486 | |
487 | temp_idx = (do_gtod.var_idx == 0); | |
488 | temp_varp = &do_gtod.vars[temp_idx]; | |
489 | ||
f2783c15 PM |
490 | temp_varp->tb_to_xs = new_tb_to_xs; |
491 | temp_varp->tb_orig_stamp = new_tb_stamp; | |
1da177e4 | 492 | temp_varp->stamp_xsec = new_stamp_xsec; |
0d8d4d42 | 493 | smp_mb(); |
1da177e4 LT |
494 | do_gtod.varp = temp_varp; |
495 | do_gtod.var_idx = temp_idx; | |
496 | ||
f2783c15 PM |
497 | /* |
498 | * tb_update_count is used to allow the userspace gettimeofday code | |
499 | * to assure itself that it sees a consistent view of the tb_to_xs and | |
500 | * stamp_xsec variables. It reads the tb_update_count, then reads | |
501 | * tb_to_xs and stamp_xsec and then reads tb_update_count again. If | |
502 | * the two values of tb_update_count match and are even then the | |
503 | * tb_to_xs and stamp_xsec values are consistent. If not, then it | |
504 | * loops back and reads them again until this criteria is met. | |
0a45d449 PM |
505 | * We expect the caller to have done the first increment of |
506 | * vdso_data->tb_update_count already. | |
f2783c15 | 507 | */ |
a7f290da BH |
508 | vdso_data->tb_orig_stamp = new_tb_stamp; |
509 | vdso_data->stamp_xsec = new_stamp_xsec; | |
510 | vdso_data->tb_to_xs = new_tb_to_xs; | |
511 | vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec; | |
512 | vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec; | |
0d8d4d42 | 513 | smp_wmb(); |
a7f290da | 514 | ++(vdso_data->tb_update_count); |
f2783c15 PM |
515 | } |
516 | ||
517 | /* | |
518 | * When the timebase - tb_orig_stamp gets too big, we do a manipulation | |
519 | * between tb_orig_stamp and stamp_xsec. The goal here is to keep the | |
520 | * difference tb - tb_orig_stamp small enough to always fit inside a | |
521 | * 32 bits number. This is a requirement of our fast 32 bits userland | |
522 | * implementation in the vdso. If we "miss" a call to this function | |
523 | * (interrupt latency, CPU locked in a spinlock, ...) and we end up | |
524 | * with a too big difference, then the vdso will fallback to calling | |
525 | * the syscall | |
526 | */ | |
527 | static __inline__ void timer_recalc_offset(u64 cur_tb) | |
528 | { | |
529 | unsigned long offset; | |
530 | u64 new_stamp_xsec; | |
092b8f34 | 531 | u64 tlen, t2x; |
0a45d449 PM |
532 | u64 tb, xsec_old, xsec_new; |
533 | struct gettimeofday_vars *varp; | |
f2783c15 | 534 | |
96c44507 PM |
535 | if (__USE_RTC()) |
536 | return; | |
260a4230 | 537 | tlen = current_tick_length(SHIFT_SCALE - 10); |
f2783c15 | 538 | offset = cur_tb - do_gtod.varp->tb_orig_stamp; |
0a45d449 PM |
539 | if (tlen == last_tick_len && offset < 0x80000000u) |
540 | return; | |
092b8f34 PM |
541 | if (tlen != last_tick_len) { |
542 | t2x = mulhdu(tlen << TICKLEN_SHIFT, ticklen_to_xs); | |
543 | last_tick_len = tlen; | |
544 | } else | |
545 | t2x = do_gtod.varp->tb_to_xs; | |
546 | new_stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC; | |
547 | do_div(new_stamp_xsec, 1000000000); | |
548 | new_stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC; | |
0a45d449 PM |
549 | |
550 | ++vdso_data->tb_update_count; | |
551 | smp_mb(); | |
552 | ||
553 | /* | |
554 | * Make sure time doesn't go backwards for userspace gettimeofday. | |
555 | */ | |
556 | tb = get_tb(); | |
557 | varp = do_gtod.varp; | |
558 | xsec_old = mulhdu(tb - varp->tb_orig_stamp, varp->tb_to_xs) | |
559 | + varp->stamp_xsec; | |
560 | xsec_new = mulhdu(tb - cur_tb, t2x) + new_stamp_xsec; | |
561 | if (xsec_new < xsec_old) | |
562 | new_stamp_xsec += xsec_old - xsec_new; | |
563 | ||
092b8f34 | 564 | update_gtod(cur_tb, new_stamp_xsec, t2x); |
1da177e4 LT |
565 | } |
566 | ||
567 | #ifdef CONFIG_SMP | |
568 | unsigned long profile_pc(struct pt_regs *regs) | |
569 | { | |
570 | unsigned long pc = instruction_pointer(regs); | |
571 | ||
572 | if (in_lock_functions(pc)) | |
573 | return regs->link; | |
574 | ||
575 | return pc; | |
576 | } | |
577 | EXPORT_SYMBOL(profile_pc); | |
578 | #endif | |
579 | ||
580 | #ifdef CONFIG_PPC_ISERIES | |
581 | ||
582 | /* | |
583 | * This function recalibrates the timebase based on the 49-bit time-of-day | |
584 | * value in the Titan chip. The Titan is much more accurate than the value | |
585 | * returned by the service processor for the timebase frequency. | |
586 | */ | |
587 | ||
588 | static void iSeries_tb_recal(void) | |
589 | { | |
590 | struct div_result divres; | |
591 | unsigned long titan, tb; | |
592 | tb = get_tb(); | |
593 | titan = HvCallXm_loadTod(); | |
594 | if ( iSeries_recal_titan ) { | |
595 | unsigned long tb_ticks = tb - iSeries_recal_tb; | |
596 | unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12; | |
597 | unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec; | |
598 | unsigned long new_tb_ticks_per_jiffy = (new_tb_ticks_per_sec+(HZ/2))/HZ; | |
599 | long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy; | |
600 | char sign = '+'; | |
601 | /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */ | |
602 | new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ; | |
603 | ||
604 | if ( tick_diff < 0 ) { | |
605 | tick_diff = -tick_diff; | |
606 | sign = '-'; | |
607 | } | |
608 | if ( tick_diff ) { | |
609 | if ( tick_diff < tb_ticks_per_jiffy/25 ) { | |
610 | printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n", | |
611 | new_tb_ticks_per_jiffy, sign, tick_diff ); | |
612 | tb_ticks_per_jiffy = new_tb_ticks_per_jiffy; | |
613 | tb_ticks_per_sec = new_tb_ticks_per_sec; | |
c6622f63 | 614 | calc_cputime_factors(); |
1da177e4 LT |
615 | div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres ); |
616 | do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; | |
617 | tb_to_xs = divres.result_low; | |
618 | do_gtod.varp->tb_to_xs = tb_to_xs; | |
a7f290da BH |
619 | vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; |
620 | vdso_data->tb_to_xs = tb_to_xs; | |
1da177e4 LT |
621 | } |
622 | else { | |
623 | printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" | |
624 | " new tb_ticks_per_jiffy = %lu\n" | |
625 | " old tb_ticks_per_jiffy = %lu\n", | |
626 | new_tb_ticks_per_jiffy, tb_ticks_per_jiffy ); | |
627 | } | |
628 | } | |
629 | } | |
630 | iSeries_recal_titan = titan; | |
631 | iSeries_recal_tb = tb; | |
632 | } | |
633 | #endif | |
634 | ||
635 | /* | |
636 | * For iSeries shared processors, we have to let the hypervisor | |
637 | * set the hardware decrementer. We set a virtual decrementer | |
638 | * in the lppaca and call the hypervisor if the virtual | |
639 | * decrementer is less than the current value in the hardware | |
640 | * decrementer. (almost always the new decrementer value will | |
641 | * be greater than the current hardware decementer so the hypervisor | |
642 | * call will not be needed) | |
643 | */ | |
644 | ||
1da177e4 LT |
645 | /* |
646 | * timer_interrupt - gets called when the decrementer overflows, | |
647 | * with interrupts disabled. | |
648 | */ | |
c7aeffc4 | 649 | void timer_interrupt(struct pt_regs * regs) |
1da177e4 LT |
650 | { |
651 | int next_dec; | |
f2783c15 PM |
652 | int cpu = smp_processor_id(); |
653 | unsigned long ticks; | |
654 | ||
655 | #ifdef CONFIG_PPC32 | |
656 | if (atomic_read(&ppc_n_lost_interrupts) != 0) | |
657 | do_IRQ(regs); | |
658 | #endif | |
1da177e4 LT |
659 | |
660 | irq_enter(); | |
661 | ||
1da177e4 | 662 | profile_tick(CPU_PROFILING, regs); |
c6622f63 | 663 | calculate_steal_time(); |
1da177e4 | 664 | |
f2783c15 | 665 | #ifdef CONFIG_PPC_ISERIES |
3356bb9f | 666 | get_lppaca()->int_dword.fields.decr_int = 0; |
f2783c15 PM |
667 | #endif |
668 | ||
669 | while ((ticks = tb_ticks_since(per_cpu(last_jiffy, cpu))) | |
670 | >= tb_ticks_per_jiffy) { | |
671 | /* Update last_jiffy */ | |
672 | per_cpu(last_jiffy, cpu) += tb_ticks_per_jiffy; | |
673 | /* Handle RTCL overflow on 601 */ | |
674 | if (__USE_RTC() && per_cpu(last_jiffy, cpu) >= 1000000000) | |
675 | per_cpu(last_jiffy, cpu) -= 1000000000; | |
1da177e4 | 676 | |
1da177e4 LT |
677 | /* |
678 | * We cannot disable the decrementer, so in the period | |
679 | * between this cpu's being marked offline in cpu_online_map | |
680 | * and calling stop-self, it is taking timer interrupts. | |
681 | * Avoid calling into the scheduler rebalancing code if this | |
682 | * is the case. | |
683 | */ | |
684 | if (!cpu_is_offline(cpu)) | |
c6622f63 | 685 | account_process_time(regs); |
f2783c15 | 686 | |
1da177e4 LT |
687 | /* |
688 | * No need to check whether cpu is offline here; boot_cpuid | |
689 | * should have been fixed up by now. | |
690 | */ | |
f2783c15 PM |
691 | if (cpu != boot_cpuid) |
692 | continue; | |
693 | ||
694 | write_seqlock(&xtime_lock); | |
96c44507 PM |
695 | tb_last_jiffy += tb_ticks_per_jiffy; |
696 | tb_last_stamp = per_cpu(last_jiffy, cpu); | |
f2783c15 | 697 | do_timer(regs); |
092b8f34 | 698 | timer_recalc_offset(tb_last_jiffy); |
f2783c15 PM |
699 | timer_check_rtc(); |
700 | write_sequnlock(&xtime_lock); | |
1da177e4 LT |
701 | } |
702 | ||
f2783c15 | 703 | next_dec = tb_ticks_per_jiffy - ticks; |
1da177e4 LT |
704 | set_dec(next_dec); |
705 | ||
706 | #ifdef CONFIG_PPC_ISERIES | |
937b31b1 | 707 | if (hvlpevent_is_pending()) |
74889802 | 708 | process_hvlpevents(regs); |
1da177e4 LT |
709 | #endif |
710 | ||
f2783c15 | 711 | #ifdef CONFIG_PPC64 |
8d15a3e5 | 712 | /* collect purr register values often, for accurate calculations */ |
1ababe11 | 713 | if (firmware_has_feature(FW_FEATURE_SPLPAR)) { |
1da177e4 LT |
714 | struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); |
715 | cu->current_tb = mfspr(SPRN_PURR); | |
716 | } | |
f2783c15 | 717 | #endif |
1da177e4 LT |
718 | |
719 | irq_exit(); | |
1da177e4 LT |
720 | } |
721 | ||
f2783c15 PM |
722 | void wakeup_decrementer(void) |
723 | { | |
092b8f34 | 724 | unsigned long ticks; |
f2783c15 | 725 | |
f2783c15 | 726 | /* |
092b8f34 PM |
727 | * The timebase gets saved on sleep and restored on wakeup, |
728 | * so all we need to do is to reset the decrementer. | |
f2783c15 | 729 | */ |
092b8f34 PM |
730 | ticks = tb_ticks_since(__get_cpu_var(last_jiffy)); |
731 | if (ticks < tb_ticks_per_jiffy) | |
732 | ticks = tb_ticks_per_jiffy - ticks; | |
733 | else | |
734 | ticks = 1; | |
735 | set_dec(ticks); | |
f2783c15 PM |
736 | } |
737 | ||
a5b518ed | 738 | #ifdef CONFIG_SMP |
f2783c15 PM |
739 | void __init smp_space_timers(unsigned int max_cpus) |
740 | { | |
741 | int i; | |
c6622f63 | 742 | unsigned long half = tb_ticks_per_jiffy / 2; |
f2783c15 PM |
743 | unsigned long offset = tb_ticks_per_jiffy / max_cpus; |
744 | unsigned long previous_tb = per_cpu(last_jiffy, boot_cpuid); | |
745 | ||
cbe62e2b PM |
746 | /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */ |
747 | previous_tb -= tb_ticks_per_jiffy; | |
c6622f63 PM |
748 | /* |
749 | * The stolen time calculation for POWER5 shared-processor LPAR | |
750 | * systems works better if the two threads' timebase interrupts | |
751 | * are staggered by half a jiffy with respect to each other. | |
752 | */ | |
0e551954 | 753 | for_each_possible_cpu(i) { |
c6622f63 PM |
754 | if (i == boot_cpuid) |
755 | continue; | |
756 | if (i == (boot_cpuid ^ 1)) | |
757 | per_cpu(last_jiffy, i) = | |
758 | per_cpu(last_jiffy, boot_cpuid) - half; | |
759 | else if (i & 1) | |
760 | per_cpu(last_jiffy, i) = | |
761 | per_cpu(last_jiffy, i ^ 1) + half; | |
762 | else { | |
f2783c15 PM |
763 | previous_tb += offset; |
764 | per_cpu(last_jiffy, i) = previous_tb; | |
765 | } | |
766 | } | |
767 | } | |
768 | #endif | |
769 | ||
1da177e4 LT |
770 | /* |
771 | * Scheduler clock - returns current time in nanosec units. | |
772 | * | |
773 | * Note: mulhdu(a, b) (multiply high double unsigned) returns | |
774 | * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b | |
775 | * are 64-bit unsigned numbers. | |
776 | */ | |
777 | unsigned long long sched_clock(void) | |
778 | { | |
96c44507 PM |
779 | if (__USE_RTC()) |
780 | return get_rtc(); | |
1da177e4 LT |
781 | return mulhdu(get_tb(), tb_to_ns_scale) << tb_to_ns_shift; |
782 | } | |
783 | ||
784 | int do_settimeofday(struct timespec *tv) | |
785 | { | |
786 | time_t wtm_sec, new_sec = tv->tv_sec; | |
787 | long wtm_nsec, new_nsec = tv->tv_nsec; | |
788 | unsigned long flags; | |
092b8f34 PM |
789 | u64 new_xsec; |
790 | unsigned long tb_delta; | |
1da177e4 LT |
791 | |
792 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
793 | return -EINVAL; | |
794 | ||
795 | write_seqlock_irqsave(&xtime_lock, flags); | |
f2783c15 PM |
796 | |
797 | /* | |
798 | * Updating the RTC is not the job of this code. If the time is | |
799 | * stepped under NTP, the RTC will be updated after STA_UNSYNC | |
800 | * is cleared. Tools like clock/hwclock either copy the RTC | |
1da177e4 LT |
801 | * to the system time, in which case there is no point in writing |
802 | * to the RTC again, or write to the RTC but then they don't call | |
803 | * settimeofday to perform this operation. | |
804 | */ | |
805 | #ifdef CONFIG_PPC_ISERIES | |
f2783c15 | 806 | if (first_settimeofday) { |
1da177e4 LT |
807 | iSeries_tb_recal(); |
808 | first_settimeofday = 0; | |
809 | } | |
810 | #endif | |
092b8f34 | 811 | |
0a45d449 PM |
812 | /* Make userspace gettimeofday spin until we're done. */ |
813 | ++vdso_data->tb_update_count; | |
814 | smp_mb(); | |
815 | ||
092b8f34 PM |
816 | /* |
817 | * Subtract off the number of nanoseconds since the | |
818 | * beginning of the last tick. | |
819 | * Note that since we don't increment jiffies_64 anywhere other | |
820 | * than in do_timer (since we don't have a lost tick problem), | |
821 | * wall_jiffies will always be the same as jiffies, | |
822 | * and therefore the (jiffies - wall_jiffies) computation | |
823 | * has been removed. | |
824 | */ | |
1da177e4 | 825 | tb_delta = tb_ticks_since(tb_last_stamp); |
092b8f34 PM |
826 | tb_delta = mulhdu(tb_delta, do_gtod.varp->tb_to_xs); /* in xsec */ |
827 | new_nsec -= SCALE_XSEC(tb_delta, 1000000000); | |
1da177e4 LT |
828 | |
829 | wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - new_sec); | |
830 | wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - new_nsec); | |
831 | ||
832 | set_normalized_timespec(&xtime, new_sec, new_nsec); | |
833 | set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); | |
834 | ||
835 | /* In case of a large backwards jump in time with NTP, we want the | |
836 | * clock to be updated as soon as the PLL is again in lock. | |
837 | */ | |
838 | last_rtc_update = new_sec - 658; | |
839 | ||
b149ee22 | 840 | ntp_clear(); |
1da177e4 | 841 | |
092b8f34 PM |
842 | new_xsec = xtime.tv_nsec; |
843 | if (new_xsec != 0) { | |
844 | new_xsec *= XSEC_PER_SEC; | |
5f6b5b97 PM |
845 | do_div(new_xsec, NSEC_PER_SEC); |
846 | } | |
092b8f34 | 847 | new_xsec += (u64)xtime.tv_sec * XSEC_PER_SEC; |
96c44507 | 848 | update_gtod(tb_last_jiffy, new_xsec, do_gtod.varp->tb_to_xs); |
1da177e4 | 849 | |
a7f290da BH |
850 | vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; |
851 | vdso_data->tz_dsttime = sys_tz.tz_dsttime; | |
1da177e4 LT |
852 | |
853 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
854 | clock_was_set(); | |
855 | return 0; | |
856 | } | |
857 | ||
858 | EXPORT_SYMBOL(do_settimeofday); | |
859 | ||
0bb474a4 | 860 | static int __init get_freq(char *name, int cells, unsigned long *val) |
10f7e7c1 AB |
861 | { |
862 | struct device_node *cpu; | |
10f7e7c1 | 863 | unsigned int *fp; |
0bb474a4 | 864 | int found = 0; |
10f7e7c1 | 865 | |
0bb474a4 | 866 | /* The cpu node should have timebase and clock frequency properties */ |
10f7e7c1 AB |
867 | cpu = of_find_node_by_type(NULL, "cpu"); |
868 | ||
d8a8188d | 869 | if (cpu) { |
0bb474a4 | 870 | fp = (unsigned int *)get_property(cpu, name, NULL); |
d8a8188d | 871 | if (fp) { |
0bb474a4 AB |
872 | found = 1; |
873 | *val = 0; | |
874 | while (cells--) | |
875 | *val = (*val << 32) | *fp++; | |
10f7e7c1 | 876 | } |
0bb474a4 AB |
877 | |
878 | of_node_put(cpu); | |
10f7e7c1 | 879 | } |
0bb474a4 AB |
880 | |
881 | return found; | |
882 | } | |
883 | ||
884 | void __init generic_calibrate_decr(void) | |
885 | { | |
886 | ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ | |
887 | ||
888 | if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && | |
889 | !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { | |
890 | ||
10f7e7c1 AB |
891 | printk(KERN_ERR "WARNING: Estimating decrementer frequency " |
892 | "(not found)\n"); | |
0bb474a4 | 893 | } |
10f7e7c1 | 894 | |
0bb474a4 AB |
895 | ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ |
896 | ||
897 | if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && | |
898 | !get_freq("clock-frequency", 1, &ppc_proc_freq)) { | |
899 | ||
900 | printk(KERN_ERR "WARNING: Estimating processor frequency " | |
901 | "(not found)\n"); | |
10f7e7c1 | 902 | } |
0bb474a4 | 903 | |
0fd6f717 KG |
904 | #ifdef CONFIG_BOOKE |
905 | /* Set the time base to zero */ | |
906 | mtspr(SPRN_TBWL, 0); | |
907 | mtspr(SPRN_TBWU, 0); | |
908 | ||
909 | /* Clear any pending timer interrupts */ | |
910 | mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); | |
911 | ||
912 | /* Enable decrementer interrupt */ | |
913 | mtspr(SPRN_TCR, TCR_DIE); | |
914 | #endif | |
10f7e7c1 | 915 | } |
10f7e7c1 | 916 | |
f2783c15 PM |
917 | unsigned long get_boot_time(void) |
918 | { | |
919 | struct rtc_time tm; | |
920 | ||
921 | if (ppc_md.get_boot_time) | |
922 | return ppc_md.get_boot_time(); | |
923 | if (!ppc_md.get_rtc_time) | |
924 | return 0; | |
925 | ppc_md.get_rtc_time(&tm); | |
926 | return mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, | |
927 | tm.tm_hour, tm.tm_min, tm.tm_sec); | |
928 | } | |
929 | ||
930 | /* This function is only called on the boot processor */ | |
1da177e4 LT |
931 | void __init time_init(void) |
932 | { | |
1da177e4 | 933 | unsigned long flags; |
f2783c15 | 934 | unsigned long tm = 0; |
1da177e4 | 935 | struct div_result res; |
092b8f34 | 936 | u64 scale, x; |
f2783c15 PM |
937 | unsigned shift; |
938 | ||
939 | if (ppc_md.time_init != NULL) | |
940 | timezone_offset = ppc_md.time_init(); | |
1da177e4 | 941 | |
96c44507 PM |
942 | if (__USE_RTC()) { |
943 | /* 601 processor: dec counts down by 128 every 128ns */ | |
944 | ppc_tb_freq = 1000000000; | |
945 | tb_last_stamp = get_rtcl(); | |
946 | tb_last_jiffy = tb_last_stamp; | |
947 | } else { | |
948 | /* Normal PowerPC with timebase register */ | |
949 | ppc_md.calibrate_decr(); | |
224ad80a | 950 | printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", |
96c44507 | 951 | ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); |
224ad80a | 952 | printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", |
96c44507 PM |
953 | ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); |
954 | tb_last_stamp = tb_last_jiffy = get_tb(); | |
955 | } | |
374e99d4 PM |
956 | |
957 | tb_ticks_per_jiffy = ppc_tb_freq / HZ; | |
092b8f34 | 958 | tb_ticks_per_sec = ppc_tb_freq; |
374e99d4 PM |
959 | tb_ticks_per_usec = ppc_tb_freq / 1000000; |
960 | tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000); | |
c6622f63 | 961 | calc_cputime_factors(); |
092b8f34 PM |
962 | |
963 | /* | |
964 | * Calculate the length of each tick in ns. It will not be | |
965 | * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ. | |
966 | * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq, | |
967 | * rounded up. | |
968 | */ | |
969 | x = (u64) NSEC_PER_SEC * tb_ticks_per_jiffy + ppc_tb_freq - 1; | |
970 | do_div(x, ppc_tb_freq); | |
971 | tick_nsec = x; | |
972 | last_tick_len = x << TICKLEN_SCALE; | |
973 | ||
974 | /* | |
975 | * Compute ticklen_to_xs, which is a factor which gets multiplied | |
976 | * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value. | |
977 | * It is computed as: | |
978 | * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9) | |
979 | * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT | |
0a45d449 PM |
980 | * which turns out to be N = 51 - SHIFT_HZ. |
981 | * This gives the result as a 0.64 fixed-point fraction. | |
982 | * That value is reduced by an offset amounting to 1 xsec per | |
983 | * 2^31 timebase ticks to avoid problems with time going backwards | |
984 | * by 1 xsec when we do timer_recalc_offset due to losing the | |
985 | * fractional xsec. That offset is equal to ppc_tb_freq/2^51 | |
986 | * since there are 2^20 xsec in a second. | |
092b8f34 | 987 | */ |
0a45d449 PM |
988 | div128_by_32((1ULL << 51) - ppc_tb_freq, 0, |
989 | tb_ticks_per_jiffy << SHIFT_HZ, &res); | |
092b8f34 PM |
990 | div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res); |
991 | ticklen_to_xs = res.result_low; | |
992 | ||
993 | /* Compute tb_to_xs from tick_nsec */ | |
994 | tb_to_xs = mulhdu(last_tick_len << TICKLEN_SHIFT, ticklen_to_xs); | |
374e99d4 | 995 | |
1da177e4 LT |
996 | /* |
997 | * Compute scale factor for sched_clock. | |
998 | * The calibrate_decr() function has set tb_ticks_per_sec, | |
999 | * which is the timebase frequency. | |
1000 | * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret | |
1001 | * the 128-bit result as a 64.64 fixed-point number. | |
1002 | * We then shift that number right until it is less than 1.0, | |
1003 | * giving us the scale factor and shift count to use in | |
1004 | * sched_clock(). | |
1005 | */ | |
1006 | div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); | |
1007 | scale = res.result_low; | |
1008 | for (shift = 0; res.result_high != 0; ++shift) { | |
1009 | scale = (scale >> 1) | (res.result_high << 63); | |
1010 | res.result_high >>= 1; | |
1011 | } | |
1012 | tb_to_ns_scale = scale; | |
1013 | tb_to_ns_shift = shift; | |
1014 | ||
4bd174fe | 1015 | tm = get_boot_time(); |
1da177e4 LT |
1016 | |
1017 | write_seqlock_irqsave(&xtime_lock, flags); | |
092b8f34 PM |
1018 | |
1019 | /* If platform provided a timezone (pmac), we correct the time */ | |
1020 | if (timezone_offset) { | |
1021 | sys_tz.tz_minuteswest = -timezone_offset / 60; | |
1022 | sys_tz.tz_dsttime = 0; | |
1023 | tm -= timezone_offset; | |
1024 | } | |
1025 | ||
f2783c15 PM |
1026 | xtime.tv_sec = tm; |
1027 | xtime.tv_nsec = 0; | |
1da177e4 LT |
1028 | do_gtod.varp = &do_gtod.vars[0]; |
1029 | do_gtod.var_idx = 0; | |
96c44507 | 1030 | do_gtod.varp->tb_orig_stamp = tb_last_jiffy; |
f2783c15 PM |
1031 | __get_cpu_var(last_jiffy) = tb_last_stamp; |
1032 | do_gtod.varp->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC; | |
1da177e4 LT |
1033 | do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; |
1034 | do_gtod.varp->tb_to_xs = tb_to_xs; | |
1035 | do_gtod.tb_to_us = tb_to_us; | |
a7f290da BH |
1036 | |
1037 | vdso_data->tb_orig_stamp = tb_last_jiffy; | |
1038 | vdso_data->tb_update_count = 0; | |
1039 | vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; | |
092b8f34 | 1040 | vdso_data->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC; |
a7f290da | 1041 | vdso_data->tb_to_xs = tb_to_xs; |
1da177e4 LT |
1042 | |
1043 | time_freq = 0; | |
1044 | ||
1da177e4 LT |
1045 | last_rtc_update = xtime.tv_sec; |
1046 | set_normalized_timespec(&wall_to_monotonic, | |
1047 | -xtime.tv_sec, -xtime.tv_nsec); | |
1048 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
1049 | ||
1050 | /* Not exact, but the timer interrupt takes care of this */ | |
1051 | set_dec(tb_ticks_per_jiffy); | |
1052 | } | |
1053 | ||
1da177e4 | 1054 | |
1da177e4 LT |
1055 | #define FEBRUARY 2 |
1056 | #define STARTOFTIME 1970 | |
1057 | #define SECDAY 86400L | |
1058 | #define SECYR (SECDAY * 365) | |
f2783c15 PM |
1059 | #define leapyear(year) ((year) % 4 == 0 && \ |
1060 | ((year) % 100 != 0 || (year) % 400 == 0)) | |
1da177e4 LT |
1061 | #define days_in_year(a) (leapyear(a) ? 366 : 365) |
1062 | #define days_in_month(a) (month_days[(a) - 1]) | |
1063 | ||
1064 | static int month_days[12] = { | |
1065 | 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 | |
1066 | }; | |
1067 | ||
1068 | /* | |
1069 | * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) | |
1070 | */ | |
1071 | void GregorianDay(struct rtc_time * tm) | |
1072 | { | |
1073 | int leapsToDate; | |
1074 | int lastYear; | |
1075 | int day; | |
1076 | int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; | |
1077 | ||
f2783c15 | 1078 | lastYear = tm->tm_year - 1; |
1da177e4 LT |
1079 | |
1080 | /* | |
1081 | * Number of leap corrections to apply up to end of last year | |
1082 | */ | |
f2783c15 | 1083 | leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400; |
1da177e4 LT |
1084 | |
1085 | /* | |
1086 | * This year is a leap year if it is divisible by 4 except when it is | |
1087 | * divisible by 100 unless it is divisible by 400 | |
1088 | * | |
f2783c15 | 1089 | * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was |
1da177e4 | 1090 | */ |
f2783c15 | 1091 | day = tm->tm_mon > 2 && leapyear(tm->tm_year); |
1da177e4 LT |
1092 | |
1093 | day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + | |
1094 | tm->tm_mday; | |
1095 | ||
f2783c15 | 1096 | tm->tm_wday = day % 7; |
1da177e4 LT |
1097 | } |
1098 | ||
1099 | void to_tm(int tim, struct rtc_time * tm) | |
1100 | { | |
1101 | register int i; | |
1102 | register long hms, day; | |
1103 | ||
1104 | day = tim / SECDAY; | |
1105 | hms = tim % SECDAY; | |
1106 | ||
1107 | /* Hours, minutes, seconds are easy */ | |
1108 | tm->tm_hour = hms / 3600; | |
1109 | tm->tm_min = (hms % 3600) / 60; | |
1110 | tm->tm_sec = (hms % 3600) % 60; | |
1111 | ||
1112 | /* Number of years in days */ | |
1113 | for (i = STARTOFTIME; day >= days_in_year(i); i++) | |
1114 | day -= days_in_year(i); | |
1115 | tm->tm_year = i; | |
1116 | ||
1117 | /* Number of months in days left */ | |
1118 | if (leapyear(tm->tm_year)) | |
1119 | days_in_month(FEBRUARY) = 29; | |
1120 | for (i = 1; day >= days_in_month(i); i++) | |
1121 | day -= days_in_month(i); | |
1122 | days_in_month(FEBRUARY) = 28; | |
1123 | tm->tm_mon = i; | |
1124 | ||
1125 | /* Days are what is left over (+1) from all that. */ | |
1126 | tm->tm_mday = day + 1; | |
1127 | ||
1128 | /* | |
1129 | * Determine the day of week | |
1130 | */ | |
1131 | GregorianDay(tm); | |
1132 | } | |
1133 | ||
1134 | /* Auxiliary function to compute scaling factors */ | |
1135 | /* Actually the choice of a timebase running at 1/4 the of the bus | |
1136 | * frequency giving resolution of a few tens of nanoseconds is quite nice. | |
1137 | * It makes this computation very precise (27-28 bits typically) which | |
1138 | * is optimistic considering the stability of most processor clock | |
1139 | * oscillators and the precision with which the timebase frequency | |
1140 | * is measured but does not harm. | |
1141 | */ | |
f2783c15 PM |
1142 | unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale) |
1143 | { | |
1da177e4 LT |
1144 | unsigned mlt=0, tmp, err; |
1145 | /* No concern for performance, it's done once: use a stupid | |
1146 | * but safe and compact method to find the multiplier. | |
1147 | */ | |
1148 | ||
1149 | for (tmp = 1U<<31; tmp != 0; tmp >>= 1) { | |
f2783c15 PM |
1150 | if (mulhwu(inscale, mlt|tmp) < outscale) |
1151 | mlt |= tmp; | |
1da177e4 LT |
1152 | } |
1153 | ||
1154 | /* We might still be off by 1 for the best approximation. | |
1155 | * A side effect of this is that if outscale is too large | |
1156 | * the returned value will be zero. | |
1157 | * Many corner cases have been checked and seem to work, | |
1158 | * some might have been forgotten in the test however. | |
1159 | */ | |
1160 | ||
f2783c15 PM |
1161 | err = inscale * (mlt+1); |
1162 | if (err <= inscale/2) | |
1163 | mlt++; | |
1da177e4 | 1164 | return mlt; |
f2783c15 | 1165 | } |
1da177e4 LT |
1166 | |
1167 | /* | |
1168 | * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit | |
1169 | * result. | |
1170 | */ | |
f2783c15 PM |
1171 | void div128_by_32(u64 dividend_high, u64 dividend_low, |
1172 | unsigned divisor, struct div_result *dr) | |
1da177e4 | 1173 | { |
f2783c15 PM |
1174 | unsigned long a, b, c, d; |
1175 | unsigned long w, x, y, z; | |
1176 | u64 ra, rb, rc; | |
1da177e4 LT |
1177 | |
1178 | a = dividend_high >> 32; | |
1179 | b = dividend_high & 0xffffffff; | |
1180 | c = dividend_low >> 32; | |
1181 | d = dividend_low & 0xffffffff; | |
1182 | ||
f2783c15 PM |
1183 | w = a / divisor; |
1184 | ra = ((u64)(a - (w * divisor)) << 32) + b; | |
1185 | ||
f2783c15 PM |
1186 | rb = ((u64) do_div(ra, divisor) << 32) + c; |
1187 | x = ra; | |
1da177e4 | 1188 | |
f2783c15 PM |
1189 | rc = ((u64) do_div(rb, divisor) << 32) + d; |
1190 | y = rb; | |
1191 | ||
1192 | do_div(rc, divisor); | |
1193 | z = rc; | |
1da177e4 | 1194 | |
f2783c15 PM |
1195 | dr->result_high = ((u64)w << 32) + x; |
1196 | dr->result_low = ((u64)y << 32) + z; | |
1da177e4 LT |
1197 | |
1198 | } |