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