Commit | Line | Data |
---|---|---|
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 | 79 | #ifdef CONFIG_PPC_ISERIES |
71712b45 TB |
80 | static unsigned long __initdata iSeries_recal_titan; |
81 | static signed long __initdata iSeries_recal_tb; | |
1da177e4 LT |
82 | #endif |
83 | ||
f2783c15 PM |
84 | /* The decrementer counts down by 128 every 128ns on a 601. */ |
85 | #define DECREMENTER_COUNT_601 (1000000000 / HZ) | |
86 | ||
1da177e4 LT |
87 | #define XSEC_PER_SEC (1024*1024) |
88 | ||
f2783c15 PM |
89 | #ifdef CONFIG_PPC64 |
90 | #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) | |
91 | #else | |
92 | /* compute ((xsec << 12) * max) >> 32 */ | |
93 | #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) | |
94 | #endif | |
95 | ||
1da177e4 LT |
96 | unsigned long tb_ticks_per_jiffy; |
97 | unsigned long tb_ticks_per_usec = 100; /* sane default */ | |
98 | EXPORT_SYMBOL(tb_ticks_per_usec); | |
99 | unsigned long tb_ticks_per_sec; | |
2cf82c02 | 100 | EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ |
f2783c15 PM |
101 | u64 tb_to_xs; |
102 | unsigned tb_to_us; | |
092b8f34 | 103 | |
19923c19 | 104 | #define TICKLEN_SCALE TICK_LENGTH_SHIFT |
092b8f34 PM |
105 | u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */ |
106 | u64 ticklen_to_xs; /* 0.64 fraction */ | |
107 | ||
108 | /* If last_tick_len corresponds to about 1/HZ seconds, then | |
109 | last_tick_len << TICKLEN_SHIFT will be about 2^63. */ | |
110 | #define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ) | |
111 | ||
1da177e4 | 112 | DEFINE_SPINLOCK(rtc_lock); |
6ae3db11 | 113 | EXPORT_SYMBOL_GPL(rtc_lock); |
1da177e4 | 114 | |
fc9069fe TB |
115 | static u64 tb_to_ns_scale __read_mostly; |
116 | static unsigned tb_to_ns_shift __read_mostly; | |
117 | static unsigned long boot_tb __read_mostly; | |
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 | ||
c6622f63 PM |
217 | /* |
218 | * Stuff for accounting stolen time. | |
219 | */ | |
220 | struct cpu_purr_data { | |
221 | int initialized; /* thread is running */ | |
c6622f63 PM |
222 | u64 tb; /* last TB value read */ |
223 | u64 purr; /* last PURR value read */ | |
c6622f63 PM |
224 | }; |
225 | ||
df211c8a NL |
226 | /* |
227 | * Each entry in the cpu_purr_data array is manipulated only by its | |
228 | * "owner" cpu -- usually in the timer interrupt but also occasionally | |
229 | * in process context for cpu online. As long as cpus do not touch | |
230 | * each others' cpu_purr_data, disabling local interrupts is | |
231 | * sufficient to serialize accesses. | |
232 | */ | |
c6622f63 PM |
233 | static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data); |
234 | ||
235 | static void snapshot_tb_and_purr(void *data) | |
236 | { | |
df211c8a | 237 | unsigned long flags; |
c6622f63 PM |
238 | struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data); |
239 | ||
df211c8a | 240 | local_irq_save(flags); |
cbcdb93d SR |
241 | p->tb = mftb(); |
242 | p->purr = mfspr(SPRN_PURR); | |
c6622f63 PM |
243 | wmb(); |
244 | p->initialized = 1; | |
df211c8a | 245 | local_irq_restore(flags); |
c6622f63 PM |
246 | } |
247 | ||
248 | /* | |
249 | * Called during boot when all cpus have come up. | |
250 | */ | |
251 | void snapshot_timebases(void) | |
252 | { | |
c6622f63 PM |
253 | if (!cpu_has_feature(CPU_FTR_PURR)) |
254 | return; | |
c6622f63 PM |
255 | on_each_cpu(snapshot_tb_and_purr, NULL, 0, 1); |
256 | } | |
257 | ||
df211c8a NL |
258 | /* |
259 | * Must be called with interrupts disabled. | |
260 | */ | |
c6622f63 PM |
261 | void calculate_steal_time(void) |
262 | { | |
cbcdb93d | 263 | u64 tb, purr; |
c6622f63 | 264 | s64 stolen; |
cbcdb93d | 265 | struct cpu_purr_data *pme; |
c6622f63 PM |
266 | |
267 | if (!cpu_has_feature(CPU_FTR_PURR)) | |
268 | return; | |
cbcdb93d | 269 | pme = &per_cpu(cpu_purr_data, smp_processor_id()); |
c6622f63 PM |
270 | if (!pme->initialized) |
271 | return; /* this can happen in early boot */ | |
c6622f63 | 272 | tb = mftb(); |
cbcdb93d SR |
273 | purr = mfspr(SPRN_PURR); |
274 | stolen = (tb - pme->tb) - (purr - pme->purr); | |
275 | if (stolen > 0) | |
c6622f63 | 276 | account_steal_time(current, stolen); |
c6622f63 PM |
277 | pme->tb = tb; |
278 | pme->purr = purr; | |
c6622f63 PM |
279 | } |
280 | ||
4cefebb1 | 281 | #ifdef CONFIG_PPC_SPLPAR |
c6622f63 PM |
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 | ||
71712b45 | 559 | static int __init iSeries_tb_recal(void) |
1da177e4 LT |
560 | { |
561 | struct div_result divres; | |
562 | unsigned long titan, tb; | |
71712b45 TB |
563 | |
564 | /* Make sure we only run on iSeries */ | |
565 | if (!firmware_has_feature(FW_FEATURE_ISERIES)) | |
566 | return -ENODEV; | |
567 | ||
1da177e4 LT |
568 | tb = get_tb(); |
569 | titan = HvCallXm_loadTod(); | |
570 | if ( iSeries_recal_titan ) { | |
571 | unsigned long tb_ticks = tb - iSeries_recal_tb; | |
572 | unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12; | |
573 | unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec; | |
574 | unsigned long new_tb_ticks_per_jiffy = (new_tb_ticks_per_sec+(HZ/2))/HZ; | |
575 | long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy; | |
576 | char sign = '+'; | |
577 | /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */ | |
578 | new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ; | |
579 | ||
580 | if ( tick_diff < 0 ) { | |
581 | tick_diff = -tick_diff; | |
582 | sign = '-'; | |
583 | } | |
584 | if ( tick_diff ) { | |
585 | if ( tick_diff < tb_ticks_per_jiffy/25 ) { | |
586 | printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n", | |
587 | new_tb_ticks_per_jiffy, sign, tick_diff ); | |
588 | tb_ticks_per_jiffy = new_tb_ticks_per_jiffy; | |
589 | tb_ticks_per_sec = new_tb_ticks_per_sec; | |
c6622f63 | 590 | calc_cputime_factors(); |
1da177e4 LT |
591 | div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres ); |
592 | do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; | |
593 | tb_to_xs = divres.result_low; | |
594 | do_gtod.varp->tb_to_xs = tb_to_xs; | |
a7f290da BH |
595 | vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; |
596 | vdso_data->tb_to_xs = tb_to_xs; | |
1da177e4 LT |
597 | } |
598 | else { | |
599 | printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" | |
600 | " new tb_ticks_per_jiffy = %lu\n" | |
601 | " old tb_ticks_per_jiffy = %lu\n", | |
602 | new_tb_ticks_per_jiffy, tb_ticks_per_jiffy ); | |
603 | } | |
604 | } | |
605 | } | |
606 | iSeries_recal_titan = titan; | |
607 | iSeries_recal_tb = tb; | |
71712b45 TB |
608 | |
609 | return 0; | |
1da177e4 | 610 | } |
71712b45 TB |
611 | late_initcall(iSeries_tb_recal); |
612 | ||
613 | /* Called from platform early init */ | |
614 | void __init iSeries_time_init_early(void) | |
615 | { | |
616 | iSeries_recal_tb = get_tb(); | |
617 | iSeries_recal_titan = HvCallXm_loadTod(); | |
618 | } | |
619 | #endif /* CONFIG_PPC_ISERIES */ | |
1da177e4 LT |
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 | 636 | { |
7d12e780 | 637 | struct pt_regs *old_regs; |
1da177e4 | 638 | int next_dec; |
f2783c15 PM |
639 | int cpu = smp_processor_id(); |
640 | unsigned long ticks; | |
5db9fa95 | 641 | u64 tb_next_jiffy; |
f2783c15 PM |
642 | |
643 | #ifdef CONFIG_PPC32 | |
644 | if (atomic_read(&ppc_n_lost_interrupts) != 0) | |
645 | do_IRQ(regs); | |
646 | #endif | |
1da177e4 | 647 | |
7d12e780 | 648 | old_regs = set_irq_regs(regs); |
1da177e4 LT |
649 | irq_enter(); |
650 | ||
7d12e780 | 651 | profile_tick(CPU_PROFILING); |
c6622f63 | 652 | calculate_steal_time(); |
1da177e4 | 653 | |
f2783c15 | 654 | #ifdef CONFIG_PPC_ISERIES |
501b6d29 SR |
655 | if (firmware_has_feature(FW_FEATURE_ISERIES)) |
656 | get_lppaca()->int_dword.fields.decr_int = 0; | |
f2783c15 PM |
657 | #endif |
658 | ||
659 | while ((ticks = tb_ticks_since(per_cpu(last_jiffy, cpu))) | |
660 | >= tb_ticks_per_jiffy) { | |
661 | /* Update last_jiffy */ | |
662 | per_cpu(last_jiffy, cpu) += tb_ticks_per_jiffy; | |
663 | /* Handle RTCL overflow on 601 */ | |
664 | if (__USE_RTC() && per_cpu(last_jiffy, cpu) >= 1000000000) | |
665 | per_cpu(last_jiffy, cpu) -= 1000000000; | |
1da177e4 | 666 | |
1da177e4 LT |
667 | /* |
668 | * We cannot disable the decrementer, so in the period | |
669 | * between this cpu's being marked offline in cpu_online_map | |
670 | * and calling stop-self, it is taking timer interrupts. | |
671 | * Avoid calling into the scheduler rebalancing code if this | |
672 | * is the case. | |
673 | */ | |
674 | if (!cpu_is_offline(cpu)) | |
c6622f63 | 675 | account_process_time(regs); |
f2783c15 | 676 | |
1da177e4 LT |
677 | /* |
678 | * No need to check whether cpu is offline here; boot_cpuid | |
679 | * should have been fixed up by now. | |
680 | */ | |
f2783c15 PM |
681 | if (cpu != boot_cpuid) |
682 | continue; | |
683 | ||
684 | write_seqlock(&xtime_lock); | |
5db9fa95 NL |
685 | tb_next_jiffy = tb_last_jiffy + tb_ticks_per_jiffy; |
686 | if (per_cpu(last_jiffy, cpu) >= tb_next_jiffy) { | |
687 | tb_last_jiffy = tb_next_jiffy; | |
3171a030 | 688 | do_timer(1); |
5db9fa95 NL |
689 | timer_recalc_offset(tb_last_jiffy); |
690 | timer_check_rtc(); | |
691 | } | |
f2783c15 | 692 | write_sequnlock(&xtime_lock); |
1da177e4 LT |
693 | } |
694 | ||
f2783c15 | 695 | next_dec = tb_ticks_per_jiffy - ticks; |
1da177e4 LT |
696 | set_dec(next_dec); |
697 | ||
698 | #ifdef CONFIG_PPC_ISERIES | |
501b6d29 | 699 | if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending()) |
35a84c2f | 700 | process_hvlpevents(); |
1da177e4 LT |
701 | #endif |
702 | ||
f2783c15 | 703 | #ifdef CONFIG_PPC64 |
8d15a3e5 | 704 | /* collect purr register values often, for accurate calculations */ |
1ababe11 | 705 | if (firmware_has_feature(FW_FEATURE_SPLPAR)) { |
1da177e4 LT |
706 | struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); |
707 | cu->current_tb = mfspr(SPRN_PURR); | |
708 | } | |
f2783c15 | 709 | #endif |
1da177e4 LT |
710 | |
711 | irq_exit(); | |
7d12e780 | 712 | set_irq_regs(old_regs); |
1da177e4 LT |
713 | } |
714 | ||
f2783c15 PM |
715 | void wakeup_decrementer(void) |
716 | { | |
092b8f34 | 717 | unsigned long ticks; |
f2783c15 | 718 | |
f2783c15 | 719 | /* |
092b8f34 PM |
720 | * The timebase gets saved on sleep and restored on wakeup, |
721 | * so all we need to do is to reset the decrementer. | |
f2783c15 | 722 | */ |
092b8f34 PM |
723 | ticks = tb_ticks_since(__get_cpu_var(last_jiffy)); |
724 | if (ticks < tb_ticks_per_jiffy) | |
725 | ticks = tb_ticks_per_jiffy - ticks; | |
726 | else | |
727 | ticks = 1; | |
728 | set_dec(ticks); | |
f2783c15 PM |
729 | } |
730 | ||
a5b518ed | 731 | #ifdef CONFIG_SMP |
f2783c15 PM |
732 | void __init smp_space_timers(unsigned int max_cpus) |
733 | { | |
734 | int i; | |
eb36c288 | 735 | u64 previous_tb = per_cpu(last_jiffy, boot_cpuid); |
f2783c15 | 736 | |
cbe62e2b PM |
737 | /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */ |
738 | previous_tb -= tb_ticks_per_jiffy; | |
e147ec8f | 739 | |
0e551954 | 740 | for_each_possible_cpu(i) { |
c6622f63 PM |
741 | if (i == boot_cpuid) |
742 | continue; | |
e147ec8f | 743 | per_cpu(last_jiffy, i) = previous_tb; |
f2783c15 PM |
744 | } |
745 | } | |
746 | #endif | |
747 | ||
1da177e4 LT |
748 | /* |
749 | * Scheduler clock - returns current time in nanosec units. | |
750 | * | |
751 | * Note: mulhdu(a, b) (multiply high double unsigned) returns | |
752 | * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b | |
753 | * are 64-bit unsigned numbers. | |
754 | */ | |
755 | unsigned long long sched_clock(void) | |
756 | { | |
96c44507 PM |
757 | if (__USE_RTC()) |
758 | return get_rtc(); | |
fc9069fe | 759 | return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; |
1da177e4 LT |
760 | } |
761 | ||
762 | int do_settimeofday(struct timespec *tv) | |
763 | { | |
764 | time_t wtm_sec, new_sec = tv->tv_sec; | |
765 | long wtm_nsec, new_nsec = tv->tv_nsec; | |
766 | unsigned long flags; | |
092b8f34 PM |
767 | u64 new_xsec; |
768 | unsigned long tb_delta; | |
1da177e4 LT |
769 | |
770 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
771 | return -EINVAL; | |
772 | ||
773 | write_seqlock_irqsave(&xtime_lock, flags); | |
f2783c15 PM |
774 | |
775 | /* | |
776 | * Updating the RTC is not the job of this code. If the time is | |
777 | * stepped under NTP, the RTC will be updated after STA_UNSYNC | |
778 | * is cleared. Tools like clock/hwclock either copy the RTC | |
1da177e4 LT |
779 | * to the system time, in which case there is no point in writing |
780 | * to the RTC again, or write to the RTC but then they don't call | |
781 | * settimeofday to perform this operation. | |
782 | */ | |
092b8f34 | 783 | |
0a45d449 PM |
784 | /* Make userspace gettimeofday spin until we're done. */ |
785 | ++vdso_data->tb_update_count; | |
786 | smp_mb(); | |
787 | ||
092b8f34 PM |
788 | /* |
789 | * Subtract off the number of nanoseconds since the | |
790 | * beginning of the last tick. | |
092b8f34 | 791 | */ |
eb36c288 | 792 | tb_delta = tb_ticks_since(tb_last_jiffy); |
092b8f34 PM |
793 | tb_delta = mulhdu(tb_delta, do_gtod.varp->tb_to_xs); /* in xsec */ |
794 | new_nsec -= SCALE_XSEC(tb_delta, 1000000000); | |
1da177e4 LT |
795 | |
796 | wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - new_sec); | |
797 | wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - new_nsec); | |
798 | ||
799 | set_normalized_timespec(&xtime, new_sec, new_nsec); | |
800 | set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); | |
801 | ||
802 | /* In case of a large backwards jump in time with NTP, we want the | |
803 | * clock to be updated as soon as the PLL is again in lock. | |
804 | */ | |
805 | last_rtc_update = new_sec - 658; | |
806 | ||
b149ee22 | 807 | ntp_clear(); |
1da177e4 | 808 | |
092b8f34 PM |
809 | new_xsec = xtime.tv_nsec; |
810 | if (new_xsec != 0) { | |
811 | new_xsec *= XSEC_PER_SEC; | |
5f6b5b97 PM |
812 | do_div(new_xsec, NSEC_PER_SEC); |
813 | } | |
092b8f34 | 814 | new_xsec += (u64)xtime.tv_sec * XSEC_PER_SEC; |
96c44507 | 815 | update_gtod(tb_last_jiffy, new_xsec, do_gtod.varp->tb_to_xs); |
1da177e4 | 816 | |
a7f290da BH |
817 | vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; |
818 | vdso_data->tz_dsttime = sys_tz.tz_dsttime; | |
1da177e4 LT |
819 | |
820 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
821 | clock_was_set(); | |
822 | return 0; | |
823 | } | |
824 | ||
825 | EXPORT_SYMBOL(do_settimeofday); | |
826 | ||
0bb474a4 | 827 | static int __init get_freq(char *name, int cells, unsigned long *val) |
10f7e7c1 AB |
828 | { |
829 | struct device_node *cpu; | |
a7f67bdf | 830 | const unsigned int *fp; |
0bb474a4 | 831 | int found = 0; |
10f7e7c1 | 832 | |
0bb474a4 | 833 | /* The cpu node should have timebase and clock frequency properties */ |
10f7e7c1 AB |
834 | cpu = of_find_node_by_type(NULL, "cpu"); |
835 | ||
d8a8188d | 836 | if (cpu) { |
e2eb6392 | 837 | fp = of_get_property(cpu, name, NULL); |
d8a8188d | 838 | if (fp) { |
0bb474a4 | 839 | found = 1; |
a4dc7ff0 | 840 | *val = of_read_ulong(fp, cells); |
10f7e7c1 | 841 | } |
0bb474a4 AB |
842 | |
843 | of_node_put(cpu); | |
10f7e7c1 | 844 | } |
0bb474a4 AB |
845 | |
846 | return found; | |
847 | } | |
848 | ||
849 | void __init generic_calibrate_decr(void) | |
850 | { | |
851 | ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ | |
852 | ||
853 | if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && | |
854 | !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { | |
855 | ||
10f7e7c1 AB |
856 | printk(KERN_ERR "WARNING: Estimating decrementer frequency " |
857 | "(not found)\n"); | |
0bb474a4 | 858 | } |
10f7e7c1 | 859 | |
0bb474a4 AB |
860 | ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ |
861 | ||
862 | if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && | |
863 | !get_freq("clock-frequency", 1, &ppc_proc_freq)) { | |
864 | ||
865 | printk(KERN_ERR "WARNING: Estimating processor frequency " | |
866 | "(not found)\n"); | |
10f7e7c1 | 867 | } |
0bb474a4 | 868 | |
0fd6f717 KG |
869 | #ifdef CONFIG_BOOKE |
870 | /* Set the time base to zero */ | |
871 | mtspr(SPRN_TBWL, 0); | |
872 | mtspr(SPRN_TBWU, 0); | |
873 | ||
874 | /* Clear any pending timer interrupts */ | |
875 | mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); | |
876 | ||
877 | /* Enable decrementer interrupt */ | |
878 | mtspr(SPRN_TCR, TCR_DIE); | |
879 | #endif | |
10f7e7c1 | 880 | } |
10f7e7c1 | 881 | |
f2783c15 PM |
882 | unsigned long get_boot_time(void) |
883 | { | |
884 | struct rtc_time tm; | |
885 | ||
886 | if (ppc_md.get_boot_time) | |
887 | return ppc_md.get_boot_time(); | |
888 | if (!ppc_md.get_rtc_time) | |
889 | return 0; | |
890 | ppc_md.get_rtc_time(&tm); | |
891 | return mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, | |
892 | tm.tm_hour, tm.tm_min, tm.tm_sec); | |
893 | } | |
894 | ||
895 | /* This function is only called on the boot processor */ | |
1da177e4 LT |
896 | void __init time_init(void) |
897 | { | |
1da177e4 | 898 | unsigned long flags; |
f2783c15 | 899 | unsigned long tm = 0; |
1da177e4 | 900 | struct div_result res; |
092b8f34 | 901 | u64 scale, x; |
f2783c15 PM |
902 | unsigned shift; |
903 | ||
904 | if (ppc_md.time_init != NULL) | |
905 | timezone_offset = ppc_md.time_init(); | |
1da177e4 | 906 | |
96c44507 PM |
907 | if (__USE_RTC()) { |
908 | /* 601 processor: dec counts down by 128 every 128ns */ | |
909 | ppc_tb_freq = 1000000000; | |
eb36c288 | 910 | tb_last_jiffy = get_rtcl(); |
96c44507 PM |
911 | } else { |
912 | /* Normal PowerPC with timebase register */ | |
913 | ppc_md.calibrate_decr(); | |
224ad80a | 914 | printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", |
96c44507 | 915 | ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); |
224ad80a | 916 | printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", |
96c44507 | 917 | ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); |
eb36c288 | 918 | tb_last_jiffy = get_tb(); |
96c44507 | 919 | } |
374e99d4 PM |
920 | |
921 | tb_ticks_per_jiffy = ppc_tb_freq / HZ; | |
092b8f34 | 922 | tb_ticks_per_sec = ppc_tb_freq; |
374e99d4 PM |
923 | tb_ticks_per_usec = ppc_tb_freq / 1000000; |
924 | tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000); | |
c6622f63 | 925 | calc_cputime_factors(); |
092b8f34 PM |
926 | |
927 | /* | |
928 | * Calculate the length of each tick in ns. It will not be | |
929 | * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ. | |
930 | * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq, | |
931 | * rounded up. | |
932 | */ | |
933 | x = (u64) NSEC_PER_SEC * tb_ticks_per_jiffy + ppc_tb_freq - 1; | |
934 | do_div(x, ppc_tb_freq); | |
935 | tick_nsec = x; | |
936 | last_tick_len = x << TICKLEN_SCALE; | |
937 | ||
938 | /* | |
939 | * Compute ticklen_to_xs, which is a factor which gets multiplied | |
940 | * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value. | |
941 | * It is computed as: | |
942 | * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9) | |
943 | * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT | |
0a45d449 PM |
944 | * which turns out to be N = 51 - SHIFT_HZ. |
945 | * This gives the result as a 0.64 fixed-point fraction. | |
946 | * That value is reduced by an offset amounting to 1 xsec per | |
947 | * 2^31 timebase ticks to avoid problems with time going backwards | |
948 | * by 1 xsec when we do timer_recalc_offset due to losing the | |
949 | * fractional xsec. That offset is equal to ppc_tb_freq/2^51 | |
950 | * since there are 2^20 xsec in a second. | |
092b8f34 | 951 | */ |
0a45d449 PM |
952 | div128_by_32((1ULL << 51) - ppc_tb_freq, 0, |
953 | tb_ticks_per_jiffy << SHIFT_HZ, &res); | |
092b8f34 PM |
954 | div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res); |
955 | ticklen_to_xs = res.result_low; | |
956 | ||
957 | /* Compute tb_to_xs from tick_nsec */ | |
958 | tb_to_xs = mulhdu(last_tick_len << TICKLEN_SHIFT, ticklen_to_xs); | |
374e99d4 | 959 | |
1da177e4 LT |
960 | /* |
961 | * Compute scale factor for sched_clock. | |
962 | * The calibrate_decr() function has set tb_ticks_per_sec, | |
963 | * which is the timebase frequency. | |
964 | * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret | |
965 | * the 128-bit result as a 64.64 fixed-point number. | |
966 | * We then shift that number right until it is less than 1.0, | |
967 | * giving us the scale factor and shift count to use in | |
968 | * sched_clock(). | |
969 | */ | |
970 | div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); | |
971 | scale = res.result_low; | |
972 | for (shift = 0; res.result_high != 0; ++shift) { | |
973 | scale = (scale >> 1) | (res.result_high << 63); | |
974 | res.result_high >>= 1; | |
975 | } | |
976 | tb_to_ns_scale = scale; | |
977 | tb_to_ns_shift = shift; | |
fc9069fe TB |
978 | /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ |
979 | boot_tb = get_tb(); | |
1da177e4 | 980 | |
4bd174fe | 981 | tm = get_boot_time(); |
1da177e4 LT |
982 | |
983 | write_seqlock_irqsave(&xtime_lock, flags); | |
092b8f34 PM |
984 | |
985 | /* If platform provided a timezone (pmac), we correct the time */ | |
986 | if (timezone_offset) { | |
987 | sys_tz.tz_minuteswest = -timezone_offset / 60; | |
988 | sys_tz.tz_dsttime = 0; | |
989 | tm -= timezone_offset; | |
990 | } | |
991 | ||
f2783c15 PM |
992 | xtime.tv_sec = tm; |
993 | xtime.tv_nsec = 0; | |
1da177e4 LT |
994 | do_gtod.varp = &do_gtod.vars[0]; |
995 | do_gtod.var_idx = 0; | |
96c44507 | 996 | do_gtod.varp->tb_orig_stamp = tb_last_jiffy; |
eb36c288 | 997 | __get_cpu_var(last_jiffy) = tb_last_jiffy; |
f2783c15 | 998 | do_gtod.varp->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC; |
1da177e4 LT |
999 | do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; |
1000 | do_gtod.varp->tb_to_xs = tb_to_xs; | |
1001 | do_gtod.tb_to_us = tb_to_us; | |
a7f290da BH |
1002 | |
1003 | vdso_data->tb_orig_stamp = tb_last_jiffy; | |
1004 | vdso_data->tb_update_count = 0; | |
1005 | vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; | |
092b8f34 | 1006 | vdso_data->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC; |
a7f290da | 1007 | vdso_data->tb_to_xs = tb_to_xs; |
1da177e4 LT |
1008 | |
1009 | time_freq = 0; | |
1010 | ||
1da177e4 LT |
1011 | last_rtc_update = xtime.tv_sec; |
1012 | set_normalized_timespec(&wall_to_monotonic, | |
1013 | -xtime.tv_sec, -xtime.tv_nsec); | |
1014 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
1015 | ||
1016 | /* Not exact, but the timer interrupt takes care of this */ | |
1017 | set_dec(tb_ticks_per_jiffy); | |
1018 | } | |
1019 | ||
1da177e4 | 1020 | |
1da177e4 LT |
1021 | #define FEBRUARY 2 |
1022 | #define STARTOFTIME 1970 | |
1023 | #define SECDAY 86400L | |
1024 | #define SECYR (SECDAY * 365) | |
f2783c15 PM |
1025 | #define leapyear(year) ((year) % 4 == 0 && \ |
1026 | ((year) % 100 != 0 || (year) % 400 == 0)) | |
1da177e4 LT |
1027 | #define days_in_year(a) (leapyear(a) ? 366 : 365) |
1028 | #define days_in_month(a) (month_days[(a) - 1]) | |
1029 | ||
1030 | static int month_days[12] = { | |
1031 | 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 | |
1032 | }; | |
1033 | ||
1034 | /* | |
1035 | * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) | |
1036 | */ | |
1037 | void GregorianDay(struct rtc_time * tm) | |
1038 | { | |
1039 | int leapsToDate; | |
1040 | int lastYear; | |
1041 | int day; | |
1042 | int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; | |
1043 | ||
f2783c15 | 1044 | lastYear = tm->tm_year - 1; |
1da177e4 LT |
1045 | |
1046 | /* | |
1047 | * Number of leap corrections to apply up to end of last year | |
1048 | */ | |
f2783c15 | 1049 | leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400; |
1da177e4 LT |
1050 | |
1051 | /* | |
1052 | * This year is a leap year if it is divisible by 4 except when it is | |
1053 | * divisible by 100 unless it is divisible by 400 | |
1054 | * | |
f2783c15 | 1055 | * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was |
1da177e4 | 1056 | */ |
f2783c15 | 1057 | day = tm->tm_mon > 2 && leapyear(tm->tm_year); |
1da177e4 LT |
1058 | |
1059 | day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + | |
1060 | tm->tm_mday; | |
1061 | ||
f2783c15 | 1062 | tm->tm_wday = day % 7; |
1da177e4 LT |
1063 | } |
1064 | ||
1065 | void to_tm(int tim, struct rtc_time * tm) | |
1066 | { | |
1067 | register int i; | |
1068 | register long hms, day; | |
1069 | ||
1070 | day = tim / SECDAY; | |
1071 | hms = tim % SECDAY; | |
1072 | ||
1073 | /* Hours, minutes, seconds are easy */ | |
1074 | tm->tm_hour = hms / 3600; | |
1075 | tm->tm_min = (hms % 3600) / 60; | |
1076 | tm->tm_sec = (hms % 3600) % 60; | |
1077 | ||
1078 | /* Number of years in days */ | |
1079 | for (i = STARTOFTIME; day >= days_in_year(i); i++) | |
1080 | day -= days_in_year(i); | |
1081 | tm->tm_year = i; | |
1082 | ||
1083 | /* Number of months in days left */ | |
1084 | if (leapyear(tm->tm_year)) | |
1085 | days_in_month(FEBRUARY) = 29; | |
1086 | for (i = 1; day >= days_in_month(i); i++) | |
1087 | day -= days_in_month(i); | |
1088 | days_in_month(FEBRUARY) = 28; | |
1089 | tm->tm_mon = i; | |
1090 | ||
1091 | /* Days are what is left over (+1) from all that. */ | |
1092 | tm->tm_mday = day + 1; | |
1093 | ||
1094 | /* | |
1095 | * Determine the day of week | |
1096 | */ | |
1097 | GregorianDay(tm); | |
1098 | } | |
1099 | ||
1100 | /* Auxiliary function to compute scaling factors */ | |
1101 | /* Actually the choice of a timebase running at 1/4 the of the bus | |
1102 | * frequency giving resolution of a few tens of nanoseconds is quite nice. | |
1103 | * It makes this computation very precise (27-28 bits typically) which | |
1104 | * is optimistic considering the stability of most processor clock | |
1105 | * oscillators and the precision with which the timebase frequency | |
1106 | * is measured but does not harm. | |
1107 | */ | |
f2783c15 PM |
1108 | unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale) |
1109 | { | |
1da177e4 LT |
1110 | unsigned mlt=0, tmp, err; |
1111 | /* No concern for performance, it's done once: use a stupid | |
1112 | * but safe and compact method to find the multiplier. | |
1113 | */ | |
1114 | ||
1115 | for (tmp = 1U<<31; tmp != 0; tmp >>= 1) { | |
f2783c15 PM |
1116 | if (mulhwu(inscale, mlt|tmp) < outscale) |
1117 | mlt |= tmp; | |
1da177e4 LT |
1118 | } |
1119 | ||
1120 | /* We might still be off by 1 for the best approximation. | |
1121 | * A side effect of this is that if outscale is too large | |
1122 | * the returned value will be zero. | |
1123 | * Many corner cases have been checked and seem to work, | |
1124 | * some might have been forgotten in the test however. | |
1125 | */ | |
1126 | ||
f2783c15 PM |
1127 | err = inscale * (mlt+1); |
1128 | if (err <= inscale/2) | |
1129 | mlt++; | |
1da177e4 | 1130 | return mlt; |
f2783c15 | 1131 | } |
1da177e4 LT |
1132 | |
1133 | /* | |
1134 | * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit | |
1135 | * result. | |
1136 | */ | |
f2783c15 PM |
1137 | void div128_by_32(u64 dividend_high, u64 dividend_low, |
1138 | unsigned divisor, struct div_result *dr) | |
1da177e4 | 1139 | { |
f2783c15 PM |
1140 | unsigned long a, b, c, d; |
1141 | unsigned long w, x, y, z; | |
1142 | u64 ra, rb, rc; | |
1da177e4 LT |
1143 | |
1144 | a = dividend_high >> 32; | |
1145 | b = dividend_high & 0xffffffff; | |
1146 | c = dividend_low >> 32; | |
1147 | d = dividend_low & 0xffffffff; | |
1148 | ||
f2783c15 PM |
1149 | w = a / divisor; |
1150 | ra = ((u64)(a - (w * divisor)) << 32) + b; | |
1151 | ||
f2783c15 PM |
1152 | rb = ((u64) do_div(ra, divisor) << 32) + c; |
1153 | x = ra; | |
1da177e4 | 1154 | |
f2783c15 PM |
1155 | rc = ((u64) do_div(rb, divisor) << 32) + d; |
1156 | y = rb; | |
1157 | ||
1158 | do_div(rc, divisor); | |
1159 | z = rc; | |
1da177e4 | 1160 | |
f2783c15 PM |
1161 | dr->result_high = ((u64)w << 32) + x; |
1162 | dr->result_low = ((u64)y << 32) + z; | |
1da177e4 LT |
1163 | |
1164 | } |