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 | ||
1da177e4 LT |
35 | #include <linux/errno.h> |
36 | #include <linux/module.h> | |
37 | #include <linux/sched.h> | |
38 | #include <linux/kernel.h> | |
39 | #include <linux/param.h> | |
40 | #include <linux/string.h> | |
41 | #include <linux/mm.h> | |
42 | #include <linux/interrupt.h> | |
43 | #include <linux/timex.h> | |
44 | #include <linux/kernel_stat.h> | |
1da177e4 LT |
45 | #include <linux/time.h> |
46 | #include <linux/init.h> | |
47 | #include <linux/profile.h> | |
48 | #include <linux/cpu.h> | |
49 | #include <linux/security.h> | |
f2783c15 PM |
50 | #include <linux/percpu.h> |
51 | #include <linux/rtc.h> | |
092b8f34 | 52 | #include <linux/jiffies.h> |
c6622f63 | 53 | #include <linux/posix-timers.h> |
7d12e780 | 54 | #include <linux/irq.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 | 104 | |
19923c19 | 105 | #define TICKLEN_SCALE TICK_LENGTH_SHIFT |
092b8f34 PM |
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 | ||
1da177e4 | 121 | extern struct timezone sys_tz; |
f2783c15 | 122 | static long timezone_offset; |
1da177e4 | 123 | |
10f7e7c1 AB |
124 | unsigned long ppc_proc_freq; |
125 | unsigned long ppc_tb_freq; | |
126 | ||
eb36c288 PM |
127 | static u64 tb_last_jiffy __cacheline_aligned_in_smp; |
128 | static DEFINE_PER_CPU(u64, last_jiffy); | |
96c44507 | 129 | |
c6622f63 PM |
130 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING |
131 | /* | |
132 | * Factors for converting from cputime_t (timebase ticks) to | |
133 | * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds). | |
134 | * These are all stored as 0.64 fixed-point binary fractions. | |
135 | */ | |
136 | u64 __cputime_jiffies_factor; | |
2cf82c02 | 137 | EXPORT_SYMBOL(__cputime_jiffies_factor); |
c6622f63 | 138 | u64 __cputime_msec_factor; |
2cf82c02 | 139 | EXPORT_SYMBOL(__cputime_msec_factor); |
c6622f63 | 140 | u64 __cputime_sec_factor; |
2cf82c02 | 141 | EXPORT_SYMBOL(__cputime_sec_factor); |
c6622f63 | 142 | u64 __cputime_clockt_factor; |
2cf82c02 | 143 | EXPORT_SYMBOL(__cputime_clockt_factor); |
c6622f63 PM |
144 | |
145 | static void calc_cputime_factors(void) | |
146 | { | |
147 | struct div_result res; | |
148 | ||
149 | div128_by_32(HZ, 0, tb_ticks_per_sec, &res); | |
150 | __cputime_jiffies_factor = res.result_low; | |
151 | div128_by_32(1000, 0, tb_ticks_per_sec, &res); | |
152 | __cputime_msec_factor = res.result_low; | |
153 | div128_by_32(1, 0, tb_ticks_per_sec, &res); | |
154 | __cputime_sec_factor = res.result_low; | |
155 | div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); | |
156 | __cputime_clockt_factor = res.result_low; | |
157 | } | |
158 | ||
159 | /* | |
160 | * Read the PURR on systems that have it, otherwise the timebase. | |
161 | */ | |
162 | static u64 read_purr(void) | |
163 | { | |
164 | if (cpu_has_feature(CPU_FTR_PURR)) | |
165 | return mfspr(SPRN_PURR); | |
166 | return mftb(); | |
167 | } | |
168 | ||
169 | /* | |
170 | * Account time for a transition between system, hard irq | |
171 | * or soft irq state. | |
172 | */ | |
173 | void account_system_vtime(struct task_struct *tsk) | |
174 | { | |
175 | u64 now, delta; | |
176 | unsigned long flags; | |
177 | ||
178 | local_irq_save(flags); | |
179 | now = read_purr(); | |
180 | delta = now - get_paca()->startpurr; | |
181 | get_paca()->startpurr = now; | |
182 | if (!in_interrupt()) { | |
183 | delta += get_paca()->system_time; | |
184 | get_paca()->system_time = 0; | |
185 | } | |
186 | account_system_time(tsk, 0, delta); | |
187 | local_irq_restore(flags); | |
188 | } | |
189 | ||
190 | /* | |
191 | * Transfer the user and system times accumulated in the paca | |
192 | * by the exception entry and exit code to the generic process | |
193 | * user and system time records. | |
194 | * Must be called with interrupts disabled. | |
195 | */ | |
196 | void account_process_vtime(struct task_struct *tsk) | |
197 | { | |
198 | cputime_t utime; | |
199 | ||
200 | utime = get_paca()->user_time; | |
201 | get_paca()->user_time = 0; | |
202 | account_user_time(tsk, utime); | |
203 | } | |
204 | ||
205 | static void account_process_time(struct pt_regs *regs) | |
206 | { | |
207 | int cpu = smp_processor_id(); | |
208 | ||
209 | account_process_vtime(current); | |
210 | run_local_timers(); | |
211 | if (rcu_pending(cpu)) | |
212 | rcu_check_callbacks(cpu, user_mode(regs)); | |
213 | scheduler_tick(); | |
214 | run_posix_cpu_timers(current); | |
215 | } | |
216 | ||
217 | #ifdef CONFIG_PPC_SPLPAR | |
218 | /* | |
219 | * Stuff for accounting stolen time. | |
220 | */ | |
221 | struct cpu_purr_data { | |
222 | int initialized; /* thread is running */ | |
c6622f63 PM |
223 | u64 tb; /* last TB value read */ |
224 | u64 purr; /* last PURR value read */ | |
c6622f63 PM |
225 | }; |
226 | ||
df211c8a NL |
227 | /* |
228 | * Each entry in the cpu_purr_data array is manipulated only by its | |
229 | * "owner" cpu -- usually in the timer interrupt but also occasionally | |
230 | * in process context for cpu online. As long as cpus do not touch | |
231 | * each others' cpu_purr_data, disabling local interrupts is | |
232 | * sufficient to serialize accesses. | |
233 | */ | |
c6622f63 PM |
234 | static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data); |
235 | ||
236 | static void snapshot_tb_and_purr(void *data) | |
237 | { | |
df211c8a | 238 | unsigned long flags; |
c6622f63 PM |
239 | struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data); |
240 | ||
df211c8a | 241 | local_irq_save(flags); |
cbcdb93d SR |
242 | p->tb = mftb(); |
243 | p->purr = mfspr(SPRN_PURR); | |
c6622f63 PM |
244 | wmb(); |
245 | p->initialized = 1; | |
df211c8a | 246 | local_irq_restore(flags); |
c6622f63 PM |
247 | } |
248 | ||
249 | /* | |
250 | * Called during boot when all cpus have come up. | |
251 | */ | |
252 | void snapshot_timebases(void) | |
253 | { | |
c6622f63 PM |
254 | if (!cpu_has_feature(CPU_FTR_PURR)) |
255 | return; | |
c6622f63 PM |
256 | on_each_cpu(snapshot_tb_and_purr, NULL, 0, 1); |
257 | } | |
258 | ||
df211c8a NL |
259 | /* |
260 | * Must be called with interrupts disabled. | |
261 | */ | |
c6622f63 PM |
262 | void calculate_steal_time(void) |
263 | { | |
cbcdb93d | 264 | u64 tb, purr; |
c6622f63 | 265 | s64 stolen; |
cbcdb93d | 266 | struct cpu_purr_data *pme; |
c6622f63 PM |
267 | |
268 | if (!cpu_has_feature(CPU_FTR_PURR)) | |
269 | return; | |
cbcdb93d | 270 | pme = &per_cpu(cpu_purr_data, smp_processor_id()); |
c6622f63 PM |
271 | if (!pme->initialized) |
272 | return; /* this can happen in early boot */ | |
c6622f63 | 273 | tb = mftb(); |
cbcdb93d SR |
274 | purr = mfspr(SPRN_PURR); |
275 | stolen = (tb - pme->tb) - (purr - pme->purr); | |
276 | if (stolen > 0) | |
c6622f63 | 277 | account_steal_time(current, stolen); |
c6622f63 PM |
278 | pme->tb = tb; |
279 | pme->purr = purr; | |
c6622f63 PM |
280 | } |
281 | ||
282 | /* | |
283 | * Must be called before the cpu is added to the online map when | |
284 | * a cpu is being brought up at runtime. | |
285 | */ | |
286 | static void snapshot_purr(void) | |
287 | { | |
cbcdb93d | 288 | struct cpu_purr_data *pme; |
c6622f63 PM |
289 | unsigned long flags; |
290 | ||
291 | if (!cpu_has_feature(CPU_FTR_PURR)) | |
292 | return; | |
df211c8a | 293 | local_irq_save(flags); |
cbcdb93d | 294 | pme = &per_cpu(cpu_purr_data, smp_processor_id()); |
cbcdb93d SR |
295 | pme->tb = mftb(); |
296 | pme->purr = mfspr(SPRN_PURR); | |
c6622f63 | 297 | pme->initialized = 1; |
df211c8a | 298 | local_irq_restore(flags); |
c6622f63 PM |
299 | } |
300 | ||
301 | #endif /* CONFIG_PPC_SPLPAR */ | |
302 | ||
303 | #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */ | |
304 | #define calc_cputime_factors() | |
305 | #define account_process_time(regs) update_process_times(user_mode(regs)) | |
306 | #define calculate_steal_time() do { } while (0) | |
307 | #endif | |
308 | ||
309 | #if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR)) | |
310 | #define snapshot_purr() do { } while (0) | |
311 | #endif | |
312 | ||
313 | /* | |
314 | * Called when a cpu comes up after the system has finished booting, | |
315 | * i.e. as a result of a hotplug cpu action. | |
316 | */ | |
317 | void snapshot_timebase(void) | |
318 | { | |
319 | __get_cpu_var(last_jiffy) = get_tb(); | |
320 | snapshot_purr(); | |
321 | } | |
322 | ||
6defa38b PM |
323 | void __delay(unsigned long loops) |
324 | { | |
325 | unsigned long start; | |
326 | int diff; | |
327 | ||
328 | if (__USE_RTC()) { | |
329 | start = get_rtcl(); | |
330 | do { | |
331 | /* the RTCL register wraps at 1000000000 */ | |
332 | diff = get_rtcl() - start; | |
333 | if (diff < 0) | |
334 | diff += 1000000000; | |
335 | } while (diff < loops); | |
336 | } else { | |
337 | start = get_tbl(); | |
338 | while (get_tbl() - start < loops) | |
339 | HMT_low(); | |
340 | HMT_medium(); | |
341 | } | |
342 | } | |
343 | EXPORT_SYMBOL(__delay); | |
344 | ||
345 | void udelay(unsigned long usecs) | |
346 | { | |
347 | __delay(tb_ticks_per_usec * usecs); | |
348 | } | |
349 | EXPORT_SYMBOL(udelay); | |
350 | ||
1da177e4 LT |
351 | static __inline__ void timer_check_rtc(void) |
352 | { | |
353 | /* | |
354 | * update the rtc when needed, this should be performed on the | |
355 | * right fraction of a second. Half or full second ? | |
356 | * Full second works on mk48t59 clocks, others need testing. | |
357 | * Note that this update is basically only used through | |
358 | * the adjtimex system calls. Setting the HW clock in | |
359 | * any other way is a /dev/rtc and userland business. | |
360 | * This is still wrong by -0.5/+1.5 jiffies because of the | |
361 | * timer interrupt resolution and possible delay, but here we | |
362 | * hit a quantization limit which can only be solved by higher | |
363 | * resolution timers and decoupling time management from timer | |
364 | * interrupts. This is also wrong on the clocks | |
365 | * which require being written at the half second boundary. | |
366 | * We should have an rtc call that only sets the minutes and | |
367 | * seconds like on Intel to avoid problems with non UTC clocks. | |
368 | */ | |
d2e61512 | 369 | if (ppc_md.set_rtc_time && ntp_synced() && |
f2783c15 | 370 | xtime.tv_sec - last_rtc_update >= 659 && |
092b8f34 | 371 | abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ) { |
f2783c15 PM |
372 | struct rtc_time tm; |
373 | to_tm(xtime.tv_sec + 1 + timezone_offset, &tm); | |
374 | tm.tm_year -= 1900; | |
375 | tm.tm_mon -= 1; | |
376 | if (ppc_md.set_rtc_time(&tm) == 0) | |
377 | last_rtc_update = xtime.tv_sec + 1; | |
378 | else | |
379 | /* Try again one minute later */ | |
380 | last_rtc_update += 60; | |
1da177e4 LT |
381 | } |
382 | } | |
383 | ||
384 | /* | |
385 | * This version of gettimeofday has microsecond resolution. | |
386 | */ | |
5db9fa95 | 387 | static inline void __do_gettimeofday(struct timeval *tv) |
1da177e4 | 388 | { |
f2783c15 PM |
389 | unsigned long sec, usec; |
390 | u64 tb_ticks, xsec; | |
391 | struct gettimeofday_vars *temp_varp; | |
392 | u64 temp_tb_to_xs, temp_stamp_xsec; | |
1da177e4 LT |
393 | |
394 | /* | |
395 | * These calculations are faster (gets rid of divides) | |
396 | * if done in units of 1/2^20 rather than microseconds. | |
397 | * The conversion to microseconds at the end is done | |
398 | * without a divide (and in fact, without a multiply) | |
399 | */ | |
400 | temp_varp = do_gtod.varp; | |
5db9fa95 NL |
401 | |
402 | /* Sampling the time base must be done after loading | |
403 | * do_gtod.varp in order to avoid racing with update_gtod. | |
404 | */ | |
405 | data_barrier(temp_varp); | |
406 | tb_ticks = get_tb() - temp_varp->tb_orig_stamp; | |
1da177e4 LT |
407 | temp_tb_to_xs = temp_varp->tb_to_xs; |
408 | temp_stamp_xsec = temp_varp->stamp_xsec; | |
f2783c15 | 409 | xsec = temp_stamp_xsec + mulhdu(tb_ticks, temp_tb_to_xs); |
1da177e4 | 410 | sec = xsec / XSEC_PER_SEC; |
f2783c15 PM |
411 | usec = (unsigned long)xsec & (XSEC_PER_SEC - 1); |
412 | usec = SCALE_XSEC(usec, 1000000); | |
1da177e4 LT |
413 | |
414 | tv->tv_sec = sec; | |
415 | tv->tv_usec = usec; | |
416 | } | |
417 | ||
418 | void do_gettimeofday(struct timeval *tv) | |
419 | { | |
96c44507 PM |
420 | if (__USE_RTC()) { |
421 | /* do this the old way */ | |
422 | unsigned long flags, seq; | |
092b8f34 | 423 | unsigned int sec, nsec, usec; |
96c44507 PM |
424 | |
425 | do { | |
426 | seq = read_seqbegin_irqsave(&xtime_lock, flags); | |
427 | sec = xtime.tv_sec; | |
eb36c288 | 428 | nsec = xtime.tv_nsec + tb_ticks_since(tb_last_jiffy); |
96c44507 | 429 | } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); |
092b8f34 | 430 | usec = nsec / 1000; |
96c44507 PM |
431 | while (usec >= 1000000) { |
432 | usec -= 1000000; | |
433 | ++sec; | |
434 | } | |
435 | tv->tv_sec = sec; | |
436 | tv->tv_usec = usec; | |
437 | return; | |
438 | } | |
5db9fa95 | 439 | __do_gettimeofday(tv); |
1da177e4 LT |
440 | } |
441 | ||
442 | EXPORT_SYMBOL(do_gettimeofday); | |
443 | ||
1da177e4 | 444 | /* |
f2783c15 PM |
445 | * There are two copies of tb_to_xs and stamp_xsec so that no |
446 | * lock is needed to access and use these values in | |
447 | * do_gettimeofday. We alternate the copies and as long as a | |
448 | * reasonable time elapses between changes, there will never | |
449 | * be inconsistent values. ntpd has a minimum of one minute | |
450 | * between updates. | |
1da177e4 | 451 | */ |
f2783c15 | 452 | static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec, |
5d14a18d | 453 | u64 new_tb_to_xs) |
1da177e4 | 454 | { |
1da177e4 | 455 | unsigned temp_idx; |
f2783c15 | 456 | struct gettimeofday_vars *temp_varp; |
1da177e4 LT |
457 | |
458 | temp_idx = (do_gtod.var_idx == 0); | |
459 | temp_varp = &do_gtod.vars[temp_idx]; | |
460 | ||
f2783c15 PM |
461 | temp_varp->tb_to_xs = new_tb_to_xs; |
462 | temp_varp->tb_orig_stamp = new_tb_stamp; | |
1da177e4 | 463 | temp_varp->stamp_xsec = new_stamp_xsec; |
0d8d4d42 | 464 | smp_mb(); |
1da177e4 LT |
465 | do_gtod.varp = temp_varp; |
466 | do_gtod.var_idx = temp_idx; | |
467 | ||
f2783c15 PM |
468 | /* |
469 | * tb_update_count is used to allow the userspace gettimeofday code | |
470 | * to assure itself that it sees a consistent view of the tb_to_xs and | |
471 | * stamp_xsec variables. It reads the tb_update_count, then reads | |
472 | * tb_to_xs and stamp_xsec and then reads tb_update_count again. If | |
473 | * the two values of tb_update_count match and are even then the | |
474 | * tb_to_xs and stamp_xsec values are consistent. If not, then it | |
475 | * loops back and reads them again until this criteria is met. | |
0a45d449 PM |
476 | * We expect the caller to have done the first increment of |
477 | * vdso_data->tb_update_count already. | |
f2783c15 | 478 | */ |
a7f290da BH |
479 | vdso_data->tb_orig_stamp = new_tb_stamp; |
480 | vdso_data->stamp_xsec = new_stamp_xsec; | |
481 | vdso_data->tb_to_xs = new_tb_to_xs; | |
482 | vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec; | |
483 | vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec; | |
0d8d4d42 | 484 | smp_wmb(); |
a7f290da | 485 | ++(vdso_data->tb_update_count); |
f2783c15 PM |
486 | } |
487 | ||
488 | /* | |
489 | * When the timebase - tb_orig_stamp gets too big, we do a manipulation | |
490 | * between tb_orig_stamp and stamp_xsec. The goal here is to keep the | |
491 | * difference tb - tb_orig_stamp small enough to always fit inside a | |
492 | * 32 bits number. This is a requirement of our fast 32 bits userland | |
493 | * implementation in the vdso. If we "miss" a call to this function | |
494 | * (interrupt latency, CPU locked in a spinlock, ...) and we end up | |
495 | * with a too big difference, then the vdso will fallback to calling | |
496 | * the syscall | |
497 | */ | |
498 | static __inline__ void timer_recalc_offset(u64 cur_tb) | |
499 | { | |
500 | unsigned long offset; | |
501 | u64 new_stamp_xsec; | |
092b8f34 | 502 | u64 tlen, t2x; |
0a45d449 PM |
503 | u64 tb, xsec_old, xsec_new; |
504 | struct gettimeofday_vars *varp; | |
f2783c15 | 505 | |
96c44507 PM |
506 | if (__USE_RTC()) |
507 | return; | |
19923c19 | 508 | tlen = current_tick_length(); |
f2783c15 | 509 | offset = cur_tb - do_gtod.varp->tb_orig_stamp; |
0a45d449 PM |
510 | if (tlen == last_tick_len && offset < 0x80000000u) |
511 | return; | |
092b8f34 PM |
512 | if (tlen != last_tick_len) { |
513 | t2x = mulhdu(tlen << TICKLEN_SHIFT, ticklen_to_xs); | |
514 | last_tick_len = tlen; | |
515 | } else | |
516 | t2x = do_gtod.varp->tb_to_xs; | |
517 | new_stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC; | |
518 | do_div(new_stamp_xsec, 1000000000); | |
519 | new_stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC; | |
0a45d449 PM |
520 | |
521 | ++vdso_data->tb_update_count; | |
522 | smp_mb(); | |
523 | ||
524 | /* | |
525 | * Make sure time doesn't go backwards for userspace gettimeofday. | |
526 | */ | |
527 | tb = get_tb(); | |
528 | varp = do_gtod.varp; | |
529 | xsec_old = mulhdu(tb - varp->tb_orig_stamp, varp->tb_to_xs) | |
530 | + varp->stamp_xsec; | |
531 | xsec_new = mulhdu(tb - cur_tb, t2x) + new_stamp_xsec; | |
532 | if (xsec_new < xsec_old) | |
533 | new_stamp_xsec += xsec_old - xsec_new; | |
534 | ||
092b8f34 | 535 | update_gtod(cur_tb, new_stamp_xsec, t2x); |
1da177e4 LT |
536 | } |
537 | ||
538 | #ifdef CONFIG_SMP | |
539 | unsigned long profile_pc(struct pt_regs *regs) | |
540 | { | |
541 | unsigned long pc = instruction_pointer(regs); | |
542 | ||
543 | if (in_lock_functions(pc)) | |
544 | return regs->link; | |
545 | ||
546 | return pc; | |
547 | } | |
548 | EXPORT_SYMBOL(profile_pc); | |
549 | #endif | |
550 | ||
551 | #ifdef CONFIG_PPC_ISERIES | |
552 | ||
553 | /* | |
554 | * This function recalibrates the timebase based on the 49-bit time-of-day | |
555 | * value in the Titan chip. The Titan is much more accurate than the value | |
556 | * returned by the service processor for the timebase frequency. | |
557 | */ | |
558 | ||
559 | static void iSeries_tb_recal(void) | |
560 | { | |
561 | struct div_result divres; | |
562 | unsigned long titan, tb; | |
563 | tb = get_tb(); | |
564 | titan = HvCallXm_loadTod(); | |
565 | if ( iSeries_recal_titan ) { | |
566 | unsigned long tb_ticks = tb - iSeries_recal_tb; | |
567 | unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12; | |
568 | unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec; | |
569 | unsigned long new_tb_ticks_per_jiffy = (new_tb_ticks_per_sec+(HZ/2))/HZ; | |
570 | long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy; | |
571 | char sign = '+'; | |
572 | /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */ | |
573 | new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ; | |
574 | ||
575 | if ( tick_diff < 0 ) { | |
576 | tick_diff = -tick_diff; | |
577 | sign = '-'; | |
578 | } | |
579 | if ( tick_diff ) { | |
580 | if ( tick_diff < tb_ticks_per_jiffy/25 ) { | |
581 | printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n", | |
582 | new_tb_ticks_per_jiffy, sign, tick_diff ); | |
583 | tb_ticks_per_jiffy = new_tb_ticks_per_jiffy; | |
584 | tb_ticks_per_sec = new_tb_ticks_per_sec; | |
c6622f63 | 585 | calc_cputime_factors(); |
1da177e4 LT |
586 | div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres ); |
587 | do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; | |
588 | tb_to_xs = divres.result_low; | |
589 | do_gtod.varp->tb_to_xs = tb_to_xs; | |
a7f290da BH |
590 | vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; |
591 | vdso_data->tb_to_xs = tb_to_xs; | |
1da177e4 LT |
592 | } |
593 | else { | |
594 | printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" | |
595 | " new tb_ticks_per_jiffy = %lu\n" | |
596 | " old tb_ticks_per_jiffy = %lu\n", | |
597 | new_tb_ticks_per_jiffy, tb_ticks_per_jiffy ); | |
598 | } | |
599 | } | |
600 | } | |
601 | iSeries_recal_titan = titan; | |
602 | iSeries_recal_tb = tb; | |
603 | } | |
604 | #endif | |
605 | ||
606 | /* | |
607 | * For iSeries shared processors, we have to let the hypervisor | |
608 | * set the hardware decrementer. We set a virtual decrementer | |
609 | * in the lppaca and call the hypervisor if the virtual | |
610 | * decrementer is less than the current value in the hardware | |
611 | * decrementer. (almost always the new decrementer value will | |
612 | * be greater than the current hardware decementer so the hypervisor | |
613 | * call will not be needed) | |
614 | */ | |
615 | ||
1da177e4 LT |
616 | /* |
617 | * timer_interrupt - gets called when the decrementer overflows, | |
618 | * with interrupts disabled. | |
619 | */ | |
c7aeffc4 | 620 | void timer_interrupt(struct pt_regs * regs) |
1da177e4 | 621 | { |
7d12e780 | 622 | struct pt_regs *old_regs; |
1da177e4 | 623 | int next_dec; |
f2783c15 PM |
624 | int cpu = smp_processor_id(); |
625 | unsigned long ticks; | |
5db9fa95 | 626 | u64 tb_next_jiffy; |
f2783c15 PM |
627 | |
628 | #ifdef CONFIG_PPC32 | |
629 | if (atomic_read(&ppc_n_lost_interrupts) != 0) | |
630 | do_IRQ(regs); | |
631 | #endif | |
1da177e4 | 632 | |
7d12e780 | 633 | old_regs = set_irq_regs(regs); |
1da177e4 LT |
634 | irq_enter(); |
635 | ||
7d12e780 | 636 | profile_tick(CPU_PROFILING); |
c6622f63 | 637 | calculate_steal_time(); |
1da177e4 | 638 | |
f2783c15 | 639 | #ifdef CONFIG_PPC_ISERIES |
501b6d29 SR |
640 | if (firmware_has_feature(FW_FEATURE_ISERIES)) |
641 | get_lppaca()->int_dword.fields.decr_int = 0; | |
f2783c15 PM |
642 | #endif |
643 | ||
644 | while ((ticks = tb_ticks_since(per_cpu(last_jiffy, cpu))) | |
645 | >= tb_ticks_per_jiffy) { | |
646 | /* Update last_jiffy */ | |
647 | per_cpu(last_jiffy, cpu) += tb_ticks_per_jiffy; | |
648 | /* Handle RTCL overflow on 601 */ | |
649 | if (__USE_RTC() && per_cpu(last_jiffy, cpu) >= 1000000000) | |
650 | per_cpu(last_jiffy, cpu) -= 1000000000; | |
1da177e4 | 651 | |
1da177e4 LT |
652 | /* |
653 | * We cannot disable the decrementer, so in the period | |
654 | * between this cpu's being marked offline in cpu_online_map | |
655 | * and calling stop-self, it is taking timer interrupts. | |
656 | * Avoid calling into the scheduler rebalancing code if this | |
657 | * is the case. | |
658 | */ | |
659 | if (!cpu_is_offline(cpu)) | |
c6622f63 | 660 | account_process_time(regs); |
f2783c15 | 661 | |
1da177e4 LT |
662 | /* |
663 | * No need to check whether cpu is offline here; boot_cpuid | |
664 | * should have been fixed up by now. | |
665 | */ | |
f2783c15 PM |
666 | if (cpu != boot_cpuid) |
667 | continue; | |
668 | ||
669 | write_seqlock(&xtime_lock); | |
5db9fa95 NL |
670 | tb_next_jiffy = tb_last_jiffy + tb_ticks_per_jiffy; |
671 | if (per_cpu(last_jiffy, cpu) >= tb_next_jiffy) { | |
672 | tb_last_jiffy = tb_next_jiffy; | |
3171a030 | 673 | do_timer(1); |
5db9fa95 NL |
674 | timer_recalc_offset(tb_last_jiffy); |
675 | timer_check_rtc(); | |
676 | } | |
f2783c15 | 677 | write_sequnlock(&xtime_lock); |
1da177e4 LT |
678 | } |
679 | ||
f2783c15 | 680 | next_dec = tb_ticks_per_jiffy - ticks; |
1da177e4 LT |
681 | set_dec(next_dec); |
682 | ||
683 | #ifdef CONFIG_PPC_ISERIES | |
501b6d29 | 684 | if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending()) |
35a84c2f | 685 | process_hvlpevents(); |
1da177e4 LT |
686 | #endif |
687 | ||
f2783c15 | 688 | #ifdef CONFIG_PPC64 |
8d15a3e5 | 689 | /* collect purr register values often, for accurate calculations */ |
1ababe11 | 690 | if (firmware_has_feature(FW_FEATURE_SPLPAR)) { |
1da177e4 LT |
691 | struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); |
692 | cu->current_tb = mfspr(SPRN_PURR); | |
693 | } | |
f2783c15 | 694 | #endif |
1da177e4 LT |
695 | |
696 | irq_exit(); | |
7d12e780 | 697 | set_irq_regs(old_regs); |
1da177e4 LT |
698 | } |
699 | ||
f2783c15 PM |
700 | void wakeup_decrementer(void) |
701 | { | |
092b8f34 | 702 | unsigned long ticks; |
f2783c15 | 703 | |
f2783c15 | 704 | /* |
092b8f34 PM |
705 | * The timebase gets saved on sleep and restored on wakeup, |
706 | * so all we need to do is to reset the decrementer. | |
f2783c15 | 707 | */ |
092b8f34 PM |
708 | ticks = tb_ticks_since(__get_cpu_var(last_jiffy)); |
709 | if (ticks < tb_ticks_per_jiffy) | |
710 | ticks = tb_ticks_per_jiffy - ticks; | |
711 | else | |
712 | ticks = 1; | |
713 | set_dec(ticks); | |
f2783c15 PM |
714 | } |
715 | ||
a5b518ed | 716 | #ifdef CONFIG_SMP |
f2783c15 PM |
717 | void __init smp_space_timers(unsigned int max_cpus) |
718 | { | |
719 | int i; | |
eb36c288 | 720 | u64 previous_tb = per_cpu(last_jiffy, boot_cpuid); |
f2783c15 | 721 | |
cbe62e2b PM |
722 | /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */ |
723 | previous_tb -= tb_ticks_per_jiffy; | |
e147ec8f | 724 | |
0e551954 | 725 | for_each_possible_cpu(i) { |
c6622f63 PM |
726 | if (i == boot_cpuid) |
727 | continue; | |
e147ec8f | 728 | per_cpu(last_jiffy, i) = previous_tb; |
f2783c15 PM |
729 | } |
730 | } | |
731 | #endif | |
732 | ||
1da177e4 LT |
733 | /* |
734 | * Scheduler clock - returns current time in nanosec units. | |
735 | * | |
736 | * Note: mulhdu(a, b) (multiply high double unsigned) returns | |
737 | * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b | |
738 | * are 64-bit unsigned numbers. | |
739 | */ | |
740 | unsigned long long sched_clock(void) | |
741 | { | |
96c44507 PM |
742 | if (__USE_RTC()) |
743 | return get_rtc(); | |
1da177e4 LT |
744 | return mulhdu(get_tb(), tb_to_ns_scale) << tb_to_ns_shift; |
745 | } | |
746 | ||
747 | int do_settimeofday(struct timespec *tv) | |
748 | { | |
749 | time_t wtm_sec, new_sec = tv->tv_sec; | |
750 | long wtm_nsec, new_nsec = tv->tv_nsec; | |
751 | unsigned long flags; | |
092b8f34 PM |
752 | u64 new_xsec; |
753 | unsigned long tb_delta; | |
1da177e4 LT |
754 | |
755 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
756 | return -EINVAL; | |
757 | ||
758 | write_seqlock_irqsave(&xtime_lock, flags); | |
f2783c15 PM |
759 | |
760 | /* | |
761 | * Updating the RTC is not the job of this code. If the time is | |
762 | * stepped under NTP, the RTC will be updated after STA_UNSYNC | |
763 | * is cleared. Tools like clock/hwclock either copy the RTC | |
1da177e4 LT |
764 | * to the system time, in which case there is no point in writing |
765 | * to the RTC again, or write to the RTC but then they don't call | |
766 | * settimeofday to perform this operation. | |
767 | */ | |
768 | #ifdef CONFIG_PPC_ISERIES | |
501b6d29 | 769 | if (firmware_has_feature(FW_FEATURE_ISERIES) && first_settimeofday) { |
1da177e4 LT |
770 | iSeries_tb_recal(); |
771 | first_settimeofday = 0; | |
772 | } | |
773 | #endif | |
092b8f34 | 774 | |
0a45d449 PM |
775 | /* Make userspace gettimeofday spin until we're done. */ |
776 | ++vdso_data->tb_update_count; | |
777 | smp_mb(); | |
778 | ||
092b8f34 PM |
779 | /* |
780 | * Subtract off the number of nanoseconds since the | |
781 | * beginning of the last tick. | |
092b8f34 | 782 | */ |
eb36c288 | 783 | tb_delta = tb_ticks_since(tb_last_jiffy); |
092b8f34 PM |
784 | tb_delta = mulhdu(tb_delta, do_gtod.varp->tb_to_xs); /* in xsec */ |
785 | new_nsec -= SCALE_XSEC(tb_delta, 1000000000); | |
1da177e4 LT |
786 | |
787 | wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - new_sec); | |
788 | wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - new_nsec); | |
789 | ||
790 | set_normalized_timespec(&xtime, new_sec, new_nsec); | |
791 | set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); | |
792 | ||
793 | /* In case of a large backwards jump in time with NTP, we want the | |
794 | * clock to be updated as soon as the PLL is again in lock. | |
795 | */ | |
796 | last_rtc_update = new_sec - 658; | |
797 | ||
b149ee22 | 798 | ntp_clear(); |
1da177e4 | 799 | |
092b8f34 PM |
800 | new_xsec = xtime.tv_nsec; |
801 | if (new_xsec != 0) { | |
802 | new_xsec *= XSEC_PER_SEC; | |
5f6b5b97 PM |
803 | do_div(new_xsec, NSEC_PER_SEC); |
804 | } | |
092b8f34 | 805 | new_xsec += (u64)xtime.tv_sec * XSEC_PER_SEC; |
96c44507 | 806 | update_gtod(tb_last_jiffy, new_xsec, do_gtod.varp->tb_to_xs); |
1da177e4 | 807 | |
a7f290da BH |
808 | vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; |
809 | vdso_data->tz_dsttime = sys_tz.tz_dsttime; | |
1da177e4 LT |
810 | |
811 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
812 | clock_was_set(); | |
813 | return 0; | |
814 | } | |
815 | ||
816 | EXPORT_SYMBOL(do_settimeofday); | |
817 | ||
0bb474a4 | 818 | static int __init get_freq(char *name, int cells, unsigned long *val) |
10f7e7c1 AB |
819 | { |
820 | struct device_node *cpu; | |
a7f67bdf | 821 | const unsigned int *fp; |
0bb474a4 | 822 | int found = 0; |
10f7e7c1 | 823 | |
0bb474a4 | 824 | /* The cpu node should have timebase and clock frequency properties */ |
10f7e7c1 AB |
825 | cpu = of_find_node_by_type(NULL, "cpu"); |
826 | ||
d8a8188d | 827 | if (cpu) { |
e2eb6392 | 828 | fp = of_get_property(cpu, name, NULL); |
d8a8188d | 829 | if (fp) { |
0bb474a4 | 830 | found = 1; |
a4dc7ff0 | 831 | *val = of_read_ulong(fp, cells); |
10f7e7c1 | 832 | } |
0bb474a4 AB |
833 | |
834 | of_node_put(cpu); | |
10f7e7c1 | 835 | } |
0bb474a4 AB |
836 | |
837 | return found; | |
838 | } | |
839 | ||
840 | void __init generic_calibrate_decr(void) | |
841 | { | |
842 | ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ | |
843 | ||
844 | if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && | |
845 | !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { | |
846 | ||
10f7e7c1 AB |
847 | printk(KERN_ERR "WARNING: Estimating decrementer frequency " |
848 | "(not found)\n"); | |
0bb474a4 | 849 | } |
10f7e7c1 | 850 | |
0bb474a4 AB |
851 | ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ |
852 | ||
853 | if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && | |
854 | !get_freq("clock-frequency", 1, &ppc_proc_freq)) { | |
855 | ||
856 | printk(KERN_ERR "WARNING: Estimating processor frequency " | |
857 | "(not found)\n"); | |
10f7e7c1 | 858 | } |
0bb474a4 | 859 | |
0fd6f717 KG |
860 | #ifdef CONFIG_BOOKE |
861 | /* Set the time base to zero */ | |
862 | mtspr(SPRN_TBWL, 0); | |
863 | mtspr(SPRN_TBWU, 0); | |
864 | ||
865 | /* Clear any pending timer interrupts */ | |
866 | mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); | |
867 | ||
868 | /* Enable decrementer interrupt */ | |
869 | mtspr(SPRN_TCR, TCR_DIE); | |
870 | #endif | |
10f7e7c1 | 871 | } |
10f7e7c1 | 872 | |
f2783c15 PM |
873 | unsigned long get_boot_time(void) |
874 | { | |
875 | struct rtc_time tm; | |
876 | ||
877 | if (ppc_md.get_boot_time) | |
878 | return ppc_md.get_boot_time(); | |
879 | if (!ppc_md.get_rtc_time) | |
880 | return 0; | |
881 | ppc_md.get_rtc_time(&tm); | |
882 | return mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, | |
883 | tm.tm_hour, tm.tm_min, tm.tm_sec); | |
884 | } | |
885 | ||
886 | /* This function is only called on the boot processor */ | |
1da177e4 LT |
887 | void __init time_init(void) |
888 | { | |
1da177e4 | 889 | unsigned long flags; |
f2783c15 | 890 | unsigned long tm = 0; |
1da177e4 | 891 | struct div_result res; |
092b8f34 | 892 | u64 scale, x; |
f2783c15 PM |
893 | unsigned shift; |
894 | ||
895 | if (ppc_md.time_init != NULL) | |
896 | timezone_offset = ppc_md.time_init(); | |
1da177e4 | 897 | |
96c44507 PM |
898 | if (__USE_RTC()) { |
899 | /* 601 processor: dec counts down by 128 every 128ns */ | |
900 | ppc_tb_freq = 1000000000; | |
eb36c288 | 901 | tb_last_jiffy = get_rtcl(); |
96c44507 PM |
902 | } else { |
903 | /* Normal PowerPC with timebase register */ | |
904 | ppc_md.calibrate_decr(); | |
224ad80a | 905 | printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", |
96c44507 | 906 | ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); |
224ad80a | 907 | printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", |
96c44507 | 908 | ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); |
eb36c288 | 909 | tb_last_jiffy = get_tb(); |
96c44507 | 910 | } |
374e99d4 PM |
911 | |
912 | tb_ticks_per_jiffy = ppc_tb_freq / HZ; | |
092b8f34 | 913 | tb_ticks_per_sec = ppc_tb_freq; |
374e99d4 PM |
914 | tb_ticks_per_usec = ppc_tb_freq / 1000000; |
915 | tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000); | |
c6622f63 | 916 | calc_cputime_factors(); |
092b8f34 PM |
917 | |
918 | /* | |
919 | * Calculate the length of each tick in ns. It will not be | |
920 | * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ. | |
921 | * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq, | |
922 | * rounded up. | |
923 | */ | |
924 | x = (u64) NSEC_PER_SEC * tb_ticks_per_jiffy + ppc_tb_freq - 1; | |
925 | do_div(x, ppc_tb_freq); | |
926 | tick_nsec = x; | |
927 | last_tick_len = x << TICKLEN_SCALE; | |
928 | ||
929 | /* | |
930 | * Compute ticklen_to_xs, which is a factor which gets multiplied | |
931 | * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value. | |
932 | * It is computed as: | |
933 | * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9) | |
934 | * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT | |
0a45d449 PM |
935 | * which turns out to be N = 51 - SHIFT_HZ. |
936 | * This gives the result as a 0.64 fixed-point fraction. | |
937 | * That value is reduced by an offset amounting to 1 xsec per | |
938 | * 2^31 timebase ticks to avoid problems with time going backwards | |
939 | * by 1 xsec when we do timer_recalc_offset due to losing the | |
940 | * fractional xsec. That offset is equal to ppc_tb_freq/2^51 | |
941 | * since there are 2^20 xsec in a second. | |
092b8f34 | 942 | */ |
0a45d449 PM |
943 | div128_by_32((1ULL << 51) - ppc_tb_freq, 0, |
944 | tb_ticks_per_jiffy << SHIFT_HZ, &res); | |
092b8f34 PM |
945 | div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res); |
946 | ticklen_to_xs = res.result_low; | |
947 | ||
948 | /* Compute tb_to_xs from tick_nsec */ | |
949 | tb_to_xs = mulhdu(last_tick_len << TICKLEN_SHIFT, ticklen_to_xs); | |
374e99d4 | 950 | |
1da177e4 LT |
951 | /* |
952 | * Compute scale factor for sched_clock. | |
953 | * The calibrate_decr() function has set tb_ticks_per_sec, | |
954 | * which is the timebase frequency. | |
955 | * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret | |
956 | * the 128-bit result as a 64.64 fixed-point number. | |
957 | * We then shift that number right until it is less than 1.0, | |
958 | * giving us the scale factor and shift count to use in | |
959 | * sched_clock(). | |
960 | */ | |
961 | div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); | |
962 | scale = res.result_low; | |
963 | for (shift = 0; res.result_high != 0; ++shift) { | |
964 | scale = (scale >> 1) | (res.result_high << 63); | |
965 | res.result_high >>= 1; | |
966 | } | |
967 | tb_to_ns_scale = scale; | |
968 | tb_to_ns_shift = shift; | |
969 | ||
4bd174fe | 970 | tm = get_boot_time(); |
1da177e4 LT |
971 | |
972 | write_seqlock_irqsave(&xtime_lock, flags); | |
092b8f34 PM |
973 | |
974 | /* If platform provided a timezone (pmac), we correct the time */ | |
975 | if (timezone_offset) { | |
976 | sys_tz.tz_minuteswest = -timezone_offset / 60; | |
977 | sys_tz.tz_dsttime = 0; | |
978 | tm -= timezone_offset; | |
979 | } | |
980 | ||
f2783c15 PM |
981 | xtime.tv_sec = tm; |
982 | xtime.tv_nsec = 0; | |
1da177e4 LT |
983 | do_gtod.varp = &do_gtod.vars[0]; |
984 | do_gtod.var_idx = 0; | |
96c44507 | 985 | do_gtod.varp->tb_orig_stamp = tb_last_jiffy; |
eb36c288 | 986 | __get_cpu_var(last_jiffy) = tb_last_jiffy; |
f2783c15 | 987 | do_gtod.varp->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC; |
1da177e4 LT |
988 | do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; |
989 | do_gtod.varp->tb_to_xs = tb_to_xs; | |
990 | do_gtod.tb_to_us = tb_to_us; | |
a7f290da BH |
991 | |
992 | vdso_data->tb_orig_stamp = tb_last_jiffy; | |
993 | vdso_data->tb_update_count = 0; | |
994 | vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; | |
092b8f34 | 995 | vdso_data->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC; |
a7f290da | 996 | vdso_data->tb_to_xs = tb_to_xs; |
1da177e4 LT |
997 | |
998 | time_freq = 0; | |
999 | ||
1da177e4 LT |
1000 | last_rtc_update = xtime.tv_sec; |
1001 | set_normalized_timespec(&wall_to_monotonic, | |
1002 | -xtime.tv_sec, -xtime.tv_nsec); | |
1003 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
1004 | ||
1005 | /* Not exact, but the timer interrupt takes care of this */ | |
1006 | set_dec(tb_ticks_per_jiffy); | |
1007 | } | |
1008 | ||
1da177e4 | 1009 | |
1da177e4 LT |
1010 | #define FEBRUARY 2 |
1011 | #define STARTOFTIME 1970 | |
1012 | #define SECDAY 86400L | |
1013 | #define SECYR (SECDAY * 365) | |
f2783c15 PM |
1014 | #define leapyear(year) ((year) % 4 == 0 && \ |
1015 | ((year) % 100 != 0 || (year) % 400 == 0)) | |
1da177e4 LT |
1016 | #define days_in_year(a) (leapyear(a) ? 366 : 365) |
1017 | #define days_in_month(a) (month_days[(a) - 1]) | |
1018 | ||
1019 | static int month_days[12] = { | |
1020 | 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 | |
1021 | }; | |
1022 | ||
1023 | /* | |
1024 | * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) | |
1025 | */ | |
1026 | void GregorianDay(struct rtc_time * tm) | |
1027 | { | |
1028 | int leapsToDate; | |
1029 | int lastYear; | |
1030 | int day; | |
1031 | int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; | |
1032 | ||
f2783c15 | 1033 | lastYear = tm->tm_year - 1; |
1da177e4 LT |
1034 | |
1035 | /* | |
1036 | * Number of leap corrections to apply up to end of last year | |
1037 | */ | |
f2783c15 | 1038 | leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400; |
1da177e4 LT |
1039 | |
1040 | /* | |
1041 | * This year is a leap year if it is divisible by 4 except when it is | |
1042 | * divisible by 100 unless it is divisible by 400 | |
1043 | * | |
f2783c15 | 1044 | * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was |
1da177e4 | 1045 | */ |
f2783c15 | 1046 | day = tm->tm_mon > 2 && leapyear(tm->tm_year); |
1da177e4 LT |
1047 | |
1048 | day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + | |
1049 | tm->tm_mday; | |
1050 | ||
f2783c15 | 1051 | tm->tm_wday = day % 7; |
1da177e4 LT |
1052 | } |
1053 | ||
1054 | void to_tm(int tim, struct rtc_time * tm) | |
1055 | { | |
1056 | register int i; | |
1057 | register long hms, day; | |
1058 | ||
1059 | day = tim / SECDAY; | |
1060 | hms = tim % SECDAY; | |
1061 | ||
1062 | /* Hours, minutes, seconds are easy */ | |
1063 | tm->tm_hour = hms / 3600; | |
1064 | tm->tm_min = (hms % 3600) / 60; | |
1065 | tm->tm_sec = (hms % 3600) % 60; | |
1066 | ||
1067 | /* Number of years in days */ | |
1068 | for (i = STARTOFTIME; day >= days_in_year(i); i++) | |
1069 | day -= days_in_year(i); | |
1070 | tm->tm_year = i; | |
1071 | ||
1072 | /* Number of months in days left */ | |
1073 | if (leapyear(tm->tm_year)) | |
1074 | days_in_month(FEBRUARY) = 29; | |
1075 | for (i = 1; day >= days_in_month(i); i++) | |
1076 | day -= days_in_month(i); | |
1077 | days_in_month(FEBRUARY) = 28; | |
1078 | tm->tm_mon = i; | |
1079 | ||
1080 | /* Days are what is left over (+1) from all that. */ | |
1081 | tm->tm_mday = day + 1; | |
1082 | ||
1083 | /* | |
1084 | * Determine the day of week | |
1085 | */ | |
1086 | GregorianDay(tm); | |
1087 | } | |
1088 | ||
1089 | /* Auxiliary function to compute scaling factors */ | |
1090 | /* Actually the choice of a timebase running at 1/4 the of the bus | |
1091 | * frequency giving resolution of a few tens of nanoseconds is quite nice. | |
1092 | * It makes this computation very precise (27-28 bits typically) which | |
1093 | * is optimistic considering the stability of most processor clock | |
1094 | * oscillators and the precision with which the timebase frequency | |
1095 | * is measured but does not harm. | |
1096 | */ | |
f2783c15 PM |
1097 | unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale) |
1098 | { | |
1da177e4 LT |
1099 | unsigned mlt=0, tmp, err; |
1100 | /* No concern for performance, it's done once: use a stupid | |
1101 | * but safe and compact method to find the multiplier. | |
1102 | */ | |
1103 | ||
1104 | for (tmp = 1U<<31; tmp != 0; tmp >>= 1) { | |
f2783c15 PM |
1105 | if (mulhwu(inscale, mlt|tmp) < outscale) |
1106 | mlt |= tmp; | |
1da177e4 LT |
1107 | } |
1108 | ||
1109 | /* We might still be off by 1 for the best approximation. | |
1110 | * A side effect of this is that if outscale is too large | |
1111 | * the returned value will be zero. | |
1112 | * Many corner cases have been checked and seem to work, | |
1113 | * some might have been forgotten in the test however. | |
1114 | */ | |
1115 | ||
f2783c15 PM |
1116 | err = inscale * (mlt+1); |
1117 | if (err <= inscale/2) | |
1118 | mlt++; | |
1da177e4 | 1119 | return mlt; |
f2783c15 | 1120 | } |
1da177e4 LT |
1121 | |
1122 | /* | |
1123 | * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit | |
1124 | * result. | |
1125 | */ | |
f2783c15 PM |
1126 | void div128_by_32(u64 dividend_high, u64 dividend_low, |
1127 | unsigned divisor, struct div_result *dr) | |
1da177e4 | 1128 | { |
f2783c15 PM |
1129 | unsigned long a, b, c, d; |
1130 | unsigned long w, x, y, z; | |
1131 | u64 ra, rb, rc; | |
1da177e4 LT |
1132 | |
1133 | a = dividend_high >> 32; | |
1134 | b = dividend_high & 0xffffffff; | |
1135 | c = dividend_low >> 32; | |
1136 | d = dividend_low & 0xffffffff; | |
1137 | ||
f2783c15 PM |
1138 | w = a / divisor; |
1139 | ra = ((u64)(a - (w * divisor)) << 32) + b; | |
1140 | ||
f2783c15 PM |
1141 | rb = ((u64) do_div(ra, divisor) << 32) + c; |
1142 | x = ra; | |
1da177e4 | 1143 | |
f2783c15 PM |
1144 | rc = ((u64) do_div(rb, divisor) << 32) + d; |
1145 | y = rb; | |
1146 | ||
1147 | do_div(rc, divisor); | |
1148 | z = rc; | |
1da177e4 | 1149 | |
f2783c15 PM |
1150 | dr->result_high = ((u64)w << 32) + x; |
1151 | dr->result_low = ((u64)y << 32) + z; | |
1da177e4 LT |
1152 | |
1153 | } |