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> |
1ababe11 | 68 | #include <asm/firmware.h> |
f2783c15 | 69 | #ifdef CONFIG_PPC_ISERIES |
8875ccfb | 70 | #include <asm/iseries/it_lp_queue.h> |
8021b8a7 | 71 | #include <asm/iseries/hv_call_xm.h> |
f2783c15 | 72 | #endif |
1da177e4 | 73 | |
4a4cfe38 TB |
74 | /* powerpc clocksource/clockevent code */ |
75 | ||
d831d0b8 | 76 | #include <linux/clockchips.h> |
4a4cfe38 TB |
77 | #include <linux/clocksource.h> |
78 | ||
79 | static cycle_t rtc_read(void); | |
80 | static struct clocksource clocksource_rtc = { | |
81 | .name = "rtc", | |
82 | .rating = 400, | |
83 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, | |
84 | .mask = CLOCKSOURCE_MASK(64), | |
85 | .shift = 22, | |
86 | .mult = 0, /* To be filled in */ | |
87 | .read = rtc_read, | |
88 | }; | |
89 | ||
90 | static cycle_t timebase_read(void); | |
91 | static struct clocksource clocksource_timebase = { | |
92 | .name = "timebase", | |
93 | .rating = 400, | |
94 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, | |
95 | .mask = CLOCKSOURCE_MASK(64), | |
96 | .shift = 22, | |
97 | .mult = 0, /* To be filled in */ | |
98 | .read = timebase_read, | |
99 | }; | |
100 | ||
d831d0b8 TB |
101 | #define DECREMENTER_MAX 0x7fffffff |
102 | ||
103 | static int decrementer_set_next_event(unsigned long evt, | |
104 | struct clock_event_device *dev); | |
105 | static void decrementer_set_mode(enum clock_event_mode mode, | |
106 | struct clock_event_device *dev); | |
107 | ||
108 | static struct clock_event_device decrementer_clockevent = { | |
109 | .name = "decrementer", | |
110 | .rating = 200, | |
111 | .shift = 32, | |
112 | .mult = 0, /* To be filled in */ | |
113 | .irq = 0, | |
114 | .set_next_event = decrementer_set_next_event, | |
115 | .set_mode = decrementer_set_mode, | |
116 | .features = CLOCK_EVT_FEAT_ONESHOT, | |
117 | }; | |
118 | ||
119 | static DEFINE_PER_CPU(struct clock_event_device, decrementers); | |
120 | void init_decrementer_clockevent(void); | |
121 | ||
1da177e4 | 122 | #ifdef CONFIG_PPC_ISERIES |
71712b45 TB |
123 | static unsigned long __initdata iSeries_recal_titan; |
124 | static signed long __initdata iSeries_recal_tb; | |
4a4cfe38 TB |
125 | |
126 | /* Forward declaration is only needed for iSereis compiles */ | |
127 | void __init clocksource_init(void); | |
1da177e4 LT |
128 | #endif |
129 | ||
130 | #define XSEC_PER_SEC (1024*1024) | |
131 | ||
f2783c15 PM |
132 | #ifdef CONFIG_PPC64 |
133 | #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) | |
134 | #else | |
135 | /* compute ((xsec << 12) * max) >> 32 */ | |
136 | #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) | |
137 | #endif | |
138 | ||
1da177e4 LT |
139 | unsigned long tb_ticks_per_jiffy; |
140 | unsigned long tb_ticks_per_usec = 100; /* sane default */ | |
141 | EXPORT_SYMBOL(tb_ticks_per_usec); | |
142 | unsigned long tb_ticks_per_sec; | |
2cf82c02 | 143 | EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ |
f2783c15 PM |
144 | u64 tb_to_xs; |
145 | unsigned tb_to_us; | |
092b8f34 | 146 | |
19923c19 | 147 | #define TICKLEN_SCALE TICK_LENGTH_SHIFT |
092b8f34 PM |
148 | u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */ |
149 | u64 ticklen_to_xs; /* 0.64 fraction */ | |
150 | ||
151 | /* If last_tick_len corresponds to about 1/HZ seconds, then | |
152 | last_tick_len << TICKLEN_SHIFT will be about 2^63. */ | |
153 | #define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ) | |
154 | ||
1da177e4 | 155 | DEFINE_SPINLOCK(rtc_lock); |
6ae3db11 | 156 | EXPORT_SYMBOL_GPL(rtc_lock); |
1da177e4 | 157 | |
fc9069fe TB |
158 | static u64 tb_to_ns_scale __read_mostly; |
159 | static unsigned tb_to_ns_shift __read_mostly; | |
160 | static unsigned long boot_tb __read_mostly; | |
1da177e4 LT |
161 | |
162 | struct gettimeofday_struct do_gtod; | |
163 | ||
1da177e4 | 164 | extern struct timezone sys_tz; |
f2783c15 | 165 | static long timezone_offset; |
1da177e4 | 166 | |
10f7e7c1 | 167 | unsigned long ppc_proc_freq; |
1474855d | 168 | EXPORT_SYMBOL(ppc_proc_freq); |
10f7e7c1 AB |
169 | unsigned long ppc_tb_freq; |
170 | ||
eb36c288 PM |
171 | static u64 tb_last_jiffy __cacheline_aligned_in_smp; |
172 | static DEFINE_PER_CPU(u64, last_jiffy); | |
96c44507 | 173 | |
c6622f63 PM |
174 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING |
175 | /* | |
176 | * Factors for converting from cputime_t (timebase ticks) to | |
177 | * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds). | |
178 | * These are all stored as 0.64 fixed-point binary fractions. | |
179 | */ | |
180 | u64 __cputime_jiffies_factor; | |
2cf82c02 | 181 | EXPORT_SYMBOL(__cputime_jiffies_factor); |
c6622f63 | 182 | u64 __cputime_msec_factor; |
2cf82c02 | 183 | EXPORT_SYMBOL(__cputime_msec_factor); |
c6622f63 | 184 | u64 __cputime_sec_factor; |
2cf82c02 | 185 | EXPORT_SYMBOL(__cputime_sec_factor); |
c6622f63 | 186 | u64 __cputime_clockt_factor; |
2cf82c02 | 187 | EXPORT_SYMBOL(__cputime_clockt_factor); |
c6622f63 PM |
188 | |
189 | static void calc_cputime_factors(void) | |
190 | { | |
191 | struct div_result res; | |
192 | ||
193 | div128_by_32(HZ, 0, tb_ticks_per_sec, &res); | |
194 | __cputime_jiffies_factor = res.result_low; | |
195 | div128_by_32(1000, 0, tb_ticks_per_sec, &res); | |
196 | __cputime_msec_factor = res.result_low; | |
197 | div128_by_32(1, 0, tb_ticks_per_sec, &res); | |
198 | __cputime_sec_factor = res.result_low; | |
199 | div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); | |
200 | __cputime_clockt_factor = res.result_low; | |
201 | } | |
202 | ||
203 | /* | |
204 | * Read the PURR on systems that have it, otherwise the timebase. | |
205 | */ | |
206 | static u64 read_purr(void) | |
207 | { | |
208 | if (cpu_has_feature(CPU_FTR_PURR)) | |
209 | return mfspr(SPRN_PURR); | |
210 | return mftb(); | |
211 | } | |
212 | ||
213 | /* | |
214 | * Account time for a transition between system, hard irq | |
215 | * or soft irq state. | |
216 | */ | |
217 | void account_system_vtime(struct task_struct *tsk) | |
218 | { | |
219 | u64 now, delta; | |
220 | unsigned long flags; | |
221 | ||
222 | local_irq_save(flags); | |
223 | now = read_purr(); | |
224 | delta = now - get_paca()->startpurr; | |
225 | get_paca()->startpurr = now; | |
226 | if (!in_interrupt()) { | |
227 | delta += get_paca()->system_time; | |
228 | get_paca()->system_time = 0; | |
229 | } | |
230 | account_system_time(tsk, 0, delta); | |
231 | local_irq_restore(flags); | |
232 | } | |
233 | ||
234 | /* | |
235 | * Transfer the user and system times accumulated in the paca | |
236 | * by the exception entry and exit code to the generic process | |
237 | * user and system time records. | |
238 | * Must be called with interrupts disabled. | |
239 | */ | |
240 | void account_process_vtime(struct task_struct *tsk) | |
241 | { | |
242 | cputime_t utime; | |
243 | ||
244 | utime = get_paca()->user_time; | |
245 | get_paca()->user_time = 0; | |
246 | account_user_time(tsk, utime); | |
247 | } | |
248 | ||
249 | static void account_process_time(struct pt_regs *regs) | |
250 | { | |
251 | int cpu = smp_processor_id(); | |
252 | ||
253 | account_process_vtime(current); | |
254 | run_local_timers(); | |
255 | if (rcu_pending(cpu)) | |
256 | rcu_check_callbacks(cpu, user_mode(regs)); | |
257 | scheduler_tick(); | |
258 | run_posix_cpu_timers(current); | |
259 | } | |
260 | ||
c6622f63 PM |
261 | /* |
262 | * Stuff for accounting stolen time. | |
263 | */ | |
264 | struct cpu_purr_data { | |
265 | int initialized; /* thread is running */ | |
c6622f63 PM |
266 | u64 tb; /* last TB value read */ |
267 | u64 purr; /* last PURR value read */ | |
c6622f63 PM |
268 | }; |
269 | ||
df211c8a NL |
270 | /* |
271 | * Each entry in the cpu_purr_data array is manipulated only by its | |
272 | * "owner" cpu -- usually in the timer interrupt but also occasionally | |
273 | * in process context for cpu online. As long as cpus do not touch | |
274 | * each others' cpu_purr_data, disabling local interrupts is | |
275 | * sufficient to serialize accesses. | |
276 | */ | |
c6622f63 PM |
277 | static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data); |
278 | ||
279 | static void snapshot_tb_and_purr(void *data) | |
280 | { | |
df211c8a | 281 | unsigned long flags; |
c6622f63 PM |
282 | struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data); |
283 | ||
df211c8a | 284 | local_irq_save(flags); |
c27da339 | 285 | p->tb = get_tb_or_rtc(); |
cbcdb93d | 286 | p->purr = mfspr(SPRN_PURR); |
c6622f63 PM |
287 | wmb(); |
288 | p->initialized = 1; | |
df211c8a | 289 | local_irq_restore(flags); |
c6622f63 PM |
290 | } |
291 | ||
292 | /* | |
293 | * Called during boot when all cpus have come up. | |
294 | */ | |
295 | void snapshot_timebases(void) | |
296 | { | |
c6622f63 PM |
297 | if (!cpu_has_feature(CPU_FTR_PURR)) |
298 | return; | |
c6622f63 PM |
299 | on_each_cpu(snapshot_tb_and_purr, NULL, 0, 1); |
300 | } | |
301 | ||
df211c8a NL |
302 | /* |
303 | * Must be called with interrupts disabled. | |
304 | */ | |
c6622f63 PM |
305 | void calculate_steal_time(void) |
306 | { | |
cbcdb93d | 307 | u64 tb, purr; |
c6622f63 | 308 | s64 stolen; |
cbcdb93d | 309 | struct cpu_purr_data *pme; |
c6622f63 PM |
310 | |
311 | if (!cpu_has_feature(CPU_FTR_PURR)) | |
312 | return; | |
cbcdb93d | 313 | pme = &per_cpu(cpu_purr_data, smp_processor_id()); |
c6622f63 PM |
314 | if (!pme->initialized) |
315 | return; /* this can happen in early boot */ | |
c6622f63 | 316 | tb = mftb(); |
cbcdb93d SR |
317 | purr = mfspr(SPRN_PURR); |
318 | stolen = (tb - pme->tb) - (purr - pme->purr); | |
319 | if (stolen > 0) | |
c6622f63 | 320 | account_steal_time(current, stolen); |
c6622f63 PM |
321 | pme->tb = tb; |
322 | pme->purr = purr; | |
c6622f63 PM |
323 | } |
324 | ||
4cefebb1 | 325 | #ifdef CONFIG_PPC_SPLPAR |
c6622f63 PM |
326 | /* |
327 | * Must be called before the cpu is added to the online map when | |
328 | * a cpu is being brought up at runtime. | |
329 | */ | |
330 | static void snapshot_purr(void) | |
331 | { | |
cbcdb93d | 332 | struct cpu_purr_data *pme; |
c6622f63 PM |
333 | unsigned long flags; |
334 | ||
335 | if (!cpu_has_feature(CPU_FTR_PURR)) | |
336 | return; | |
df211c8a | 337 | local_irq_save(flags); |
cbcdb93d | 338 | pme = &per_cpu(cpu_purr_data, smp_processor_id()); |
cbcdb93d SR |
339 | pme->tb = mftb(); |
340 | pme->purr = mfspr(SPRN_PURR); | |
c6622f63 | 341 | pme->initialized = 1; |
df211c8a | 342 | local_irq_restore(flags); |
c6622f63 PM |
343 | } |
344 | ||
345 | #endif /* CONFIG_PPC_SPLPAR */ | |
346 | ||
347 | #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */ | |
348 | #define calc_cputime_factors() | |
349 | #define account_process_time(regs) update_process_times(user_mode(regs)) | |
350 | #define calculate_steal_time() do { } while (0) | |
351 | #endif | |
352 | ||
353 | #if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR)) | |
354 | #define snapshot_purr() do { } while (0) | |
355 | #endif | |
356 | ||
357 | /* | |
358 | * Called when a cpu comes up after the system has finished booting, | |
359 | * i.e. as a result of a hotplug cpu action. | |
360 | */ | |
361 | void snapshot_timebase(void) | |
362 | { | |
c27da339 | 363 | __get_cpu_var(last_jiffy) = get_tb_or_rtc(); |
c6622f63 PM |
364 | snapshot_purr(); |
365 | } | |
366 | ||
6defa38b PM |
367 | void __delay(unsigned long loops) |
368 | { | |
369 | unsigned long start; | |
370 | int diff; | |
371 | ||
372 | if (__USE_RTC()) { | |
373 | start = get_rtcl(); | |
374 | do { | |
375 | /* the RTCL register wraps at 1000000000 */ | |
376 | diff = get_rtcl() - start; | |
377 | if (diff < 0) | |
378 | diff += 1000000000; | |
379 | } while (diff < loops); | |
380 | } else { | |
381 | start = get_tbl(); | |
382 | while (get_tbl() - start < loops) | |
383 | HMT_low(); | |
384 | HMT_medium(); | |
385 | } | |
386 | } | |
387 | EXPORT_SYMBOL(__delay); | |
388 | ||
389 | void udelay(unsigned long usecs) | |
390 | { | |
391 | __delay(tb_ticks_per_usec * usecs); | |
392 | } | |
393 | EXPORT_SYMBOL(udelay); | |
394 | ||
1da177e4 | 395 | |
1da177e4 | 396 | /* |
f2783c15 PM |
397 | * There are two copies of tb_to_xs and stamp_xsec so that no |
398 | * lock is needed to access and use these values in | |
399 | * do_gettimeofday. We alternate the copies and as long as a | |
400 | * reasonable time elapses between changes, there will never | |
401 | * be inconsistent values. ntpd has a minimum of one minute | |
402 | * between updates. | |
1da177e4 | 403 | */ |
f2783c15 | 404 | static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec, |
5d14a18d | 405 | u64 new_tb_to_xs) |
1da177e4 | 406 | { |
1da177e4 | 407 | unsigned temp_idx; |
f2783c15 | 408 | struct gettimeofday_vars *temp_varp; |
1da177e4 LT |
409 | |
410 | temp_idx = (do_gtod.var_idx == 0); | |
411 | temp_varp = &do_gtod.vars[temp_idx]; | |
412 | ||
f2783c15 PM |
413 | temp_varp->tb_to_xs = new_tb_to_xs; |
414 | temp_varp->tb_orig_stamp = new_tb_stamp; | |
1da177e4 | 415 | temp_varp->stamp_xsec = new_stamp_xsec; |
0d8d4d42 | 416 | smp_mb(); |
1da177e4 LT |
417 | do_gtod.varp = temp_varp; |
418 | do_gtod.var_idx = temp_idx; | |
419 | ||
f2783c15 PM |
420 | /* |
421 | * tb_update_count is used to allow the userspace gettimeofday code | |
422 | * to assure itself that it sees a consistent view of the tb_to_xs and | |
423 | * stamp_xsec variables. It reads the tb_update_count, then reads | |
424 | * tb_to_xs and stamp_xsec and then reads tb_update_count again. If | |
425 | * the two values of tb_update_count match and are even then the | |
426 | * tb_to_xs and stamp_xsec values are consistent. If not, then it | |
427 | * loops back and reads them again until this criteria is met. | |
0a45d449 PM |
428 | * We expect the caller to have done the first increment of |
429 | * vdso_data->tb_update_count already. | |
f2783c15 | 430 | */ |
a7f290da BH |
431 | vdso_data->tb_orig_stamp = new_tb_stamp; |
432 | vdso_data->stamp_xsec = new_stamp_xsec; | |
433 | vdso_data->tb_to_xs = new_tb_to_xs; | |
434 | vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec; | |
435 | vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec; | |
0d8d4d42 | 436 | smp_wmb(); |
a7f290da | 437 | ++(vdso_data->tb_update_count); |
f2783c15 PM |
438 | } |
439 | ||
1da177e4 LT |
440 | #ifdef CONFIG_SMP |
441 | unsigned long profile_pc(struct pt_regs *regs) | |
442 | { | |
443 | unsigned long pc = instruction_pointer(regs); | |
444 | ||
445 | if (in_lock_functions(pc)) | |
446 | return regs->link; | |
447 | ||
448 | return pc; | |
449 | } | |
450 | EXPORT_SYMBOL(profile_pc); | |
451 | #endif | |
452 | ||
453 | #ifdef CONFIG_PPC_ISERIES | |
454 | ||
455 | /* | |
456 | * This function recalibrates the timebase based on the 49-bit time-of-day | |
457 | * value in the Titan chip. The Titan is much more accurate than the value | |
458 | * returned by the service processor for the timebase frequency. | |
459 | */ | |
460 | ||
71712b45 | 461 | static int __init iSeries_tb_recal(void) |
1da177e4 LT |
462 | { |
463 | struct div_result divres; | |
464 | unsigned long titan, tb; | |
71712b45 TB |
465 | |
466 | /* Make sure we only run on iSeries */ | |
467 | if (!firmware_has_feature(FW_FEATURE_ISERIES)) | |
468 | return -ENODEV; | |
469 | ||
1da177e4 LT |
470 | tb = get_tb(); |
471 | titan = HvCallXm_loadTod(); | |
472 | if ( iSeries_recal_titan ) { | |
473 | unsigned long tb_ticks = tb - iSeries_recal_tb; | |
474 | unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12; | |
475 | unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec; | |
476 | unsigned long new_tb_ticks_per_jiffy = (new_tb_ticks_per_sec+(HZ/2))/HZ; | |
477 | long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy; | |
478 | char sign = '+'; | |
479 | /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */ | |
480 | new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ; | |
481 | ||
482 | if ( tick_diff < 0 ) { | |
483 | tick_diff = -tick_diff; | |
484 | sign = '-'; | |
485 | } | |
486 | if ( tick_diff ) { | |
487 | if ( tick_diff < tb_ticks_per_jiffy/25 ) { | |
488 | printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n", | |
489 | new_tb_ticks_per_jiffy, sign, tick_diff ); | |
490 | tb_ticks_per_jiffy = new_tb_ticks_per_jiffy; | |
491 | tb_ticks_per_sec = new_tb_ticks_per_sec; | |
c6622f63 | 492 | calc_cputime_factors(); |
1da177e4 LT |
493 | div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres ); |
494 | do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; | |
495 | tb_to_xs = divres.result_low; | |
496 | do_gtod.varp->tb_to_xs = tb_to_xs; | |
a7f290da BH |
497 | vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; |
498 | vdso_data->tb_to_xs = tb_to_xs; | |
1da177e4 LT |
499 | } |
500 | else { | |
501 | printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" | |
502 | " new tb_ticks_per_jiffy = %lu\n" | |
503 | " old tb_ticks_per_jiffy = %lu\n", | |
504 | new_tb_ticks_per_jiffy, tb_ticks_per_jiffy ); | |
505 | } | |
506 | } | |
507 | } | |
508 | iSeries_recal_titan = titan; | |
509 | iSeries_recal_tb = tb; | |
71712b45 | 510 | |
4a4cfe38 TB |
511 | /* Called here as now we know accurate values for the timebase */ |
512 | clocksource_init(); | |
71712b45 | 513 | return 0; |
1da177e4 | 514 | } |
71712b45 TB |
515 | late_initcall(iSeries_tb_recal); |
516 | ||
517 | /* Called from platform early init */ | |
518 | void __init iSeries_time_init_early(void) | |
519 | { | |
520 | iSeries_recal_tb = get_tb(); | |
521 | iSeries_recal_titan = HvCallXm_loadTod(); | |
522 | } | |
523 | #endif /* CONFIG_PPC_ISERIES */ | |
1da177e4 LT |
524 | |
525 | /* | |
526 | * For iSeries shared processors, we have to let the hypervisor | |
527 | * set the hardware decrementer. We set a virtual decrementer | |
528 | * in the lppaca and call the hypervisor if the virtual | |
529 | * decrementer is less than the current value in the hardware | |
530 | * decrementer. (almost always the new decrementer value will | |
531 | * be greater than the current hardware decementer so the hypervisor | |
532 | * call will not be needed) | |
533 | */ | |
534 | ||
1da177e4 LT |
535 | /* |
536 | * timer_interrupt - gets called when the decrementer overflows, | |
537 | * with interrupts disabled. | |
538 | */ | |
c7aeffc4 | 539 | void timer_interrupt(struct pt_regs * regs) |
1da177e4 | 540 | { |
7d12e780 | 541 | struct pt_regs *old_regs; |
f2783c15 | 542 | int cpu = smp_processor_id(); |
d831d0b8 TB |
543 | struct clock_event_device *evt = &per_cpu(decrementers, cpu); |
544 | ||
545 | /* Ensure a positive value is written to the decrementer, or else | |
546 | * some CPUs will continuue to take decrementer exceptions */ | |
547 | set_dec(DECREMENTER_MAX); | |
f2783c15 PM |
548 | |
549 | #ifdef CONFIG_PPC32 | |
550 | if (atomic_read(&ppc_n_lost_interrupts) != 0) | |
551 | do_IRQ(regs); | |
552 | #endif | |
1da177e4 | 553 | |
7d12e780 | 554 | old_regs = set_irq_regs(regs); |
1da177e4 LT |
555 | irq_enter(); |
556 | ||
c6622f63 | 557 | calculate_steal_time(); |
1da177e4 | 558 | |
f2783c15 | 559 | #ifdef CONFIG_PPC_ISERIES |
501b6d29 SR |
560 | if (firmware_has_feature(FW_FEATURE_ISERIES)) |
561 | get_lppaca()->int_dword.fields.decr_int = 0; | |
f2783c15 PM |
562 | #endif |
563 | ||
d831d0b8 TB |
564 | /* |
565 | * We cannot disable the decrementer, so in the period | |
566 | * between this cpu's being marked offline in cpu_online_map | |
567 | * and calling stop-self, it is taking timer interrupts. | |
568 | * Avoid calling into the scheduler rebalancing code if this | |
569 | * is the case. | |
570 | */ | |
571 | if (!cpu_is_offline(cpu)) | |
572 | account_process_time(regs); | |
f2783c15 | 573 | |
d831d0b8 TB |
574 | if (evt->event_handler) |
575 | evt->event_handler(evt); | |
576 | else | |
577 | evt->set_next_event(DECREMENTER_MAX, evt); | |
1da177e4 LT |
578 | |
579 | #ifdef CONFIG_PPC_ISERIES | |
501b6d29 | 580 | if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending()) |
35a84c2f | 581 | process_hvlpevents(); |
1da177e4 LT |
582 | #endif |
583 | ||
f2783c15 | 584 | #ifdef CONFIG_PPC64 |
8d15a3e5 | 585 | /* collect purr register values often, for accurate calculations */ |
1ababe11 | 586 | if (firmware_has_feature(FW_FEATURE_SPLPAR)) { |
1da177e4 LT |
587 | struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); |
588 | cu->current_tb = mfspr(SPRN_PURR); | |
589 | } | |
f2783c15 | 590 | #endif |
1da177e4 LT |
591 | |
592 | irq_exit(); | |
7d12e780 | 593 | set_irq_regs(old_regs); |
1da177e4 LT |
594 | } |
595 | ||
f2783c15 PM |
596 | void wakeup_decrementer(void) |
597 | { | |
092b8f34 | 598 | unsigned long ticks; |
f2783c15 | 599 | |
f2783c15 | 600 | /* |
092b8f34 PM |
601 | * The timebase gets saved on sleep and restored on wakeup, |
602 | * so all we need to do is to reset the decrementer. | |
f2783c15 | 603 | */ |
092b8f34 PM |
604 | ticks = tb_ticks_since(__get_cpu_var(last_jiffy)); |
605 | if (ticks < tb_ticks_per_jiffy) | |
606 | ticks = tb_ticks_per_jiffy - ticks; | |
607 | else | |
608 | ticks = 1; | |
609 | set_dec(ticks); | |
f2783c15 PM |
610 | } |
611 | ||
a5b518ed | 612 | #ifdef CONFIG_SMP |
f2783c15 PM |
613 | void __init smp_space_timers(unsigned int max_cpus) |
614 | { | |
615 | int i; | |
eb36c288 | 616 | u64 previous_tb = per_cpu(last_jiffy, boot_cpuid); |
f2783c15 | 617 | |
cbe62e2b PM |
618 | /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */ |
619 | previous_tb -= tb_ticks_per_jiffy; | |
e147ec8f | 620 | |
0e551954 | 621 | for_each_possible_cpu(i) { |
c6622f63 PM |
622 | if (i == boot_cpuid) |
623 | continue; | |
e147ec8f | 624 | per_cpu(last_jiffy, i) = previous_tb; |
f2783c15 PM |
625 | } |
626 | } | |
627 | #endif | |
628 | ||
1da177e4 LT |
629 | /* |
630 | * Scheduler clock - returns current time in nanosec units. | |
631 | * | |
632 | * Note: mulhdu(a, b) (multiply high double unsigned) returns | |
633 | * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b | |
634 | * are 64-bit unsigned numbers. | |
635 | */ | |
636 | unsigned long long sched_clock(void) | |
637 | { | |
96c44507 PM |
638 | if (__USE_RTC()) |
639 | return get_rtc(); | |
fc9069fe | 640 | return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; |
1da177e4 LT |
641 | } |
642 | ||
0bb474a4 | 643 | static int __init get_freq(char *name, int cells, unsigned long *val) |
10f7e7c1 AB |
644 | { |
645 | struct device_node *cpu; | |
a7f67bdf | 646 | const unsigned int *fp; |
0bb474a4 | 647 | int found = 0; |
10f7e7c1 | 648 | |
0bb474a4 | 649 | /* The cpu node should have timebase and clock frequency properties */ |
10f7e7c1 AB |
650 | cpu = of_find_node_by_type(NULL, "cpu"); |
651 | ||
d8a8188d | 652 | if (cpu) { |
e2eb6392 | 653 | fp = of_get_property(cpu, name, NULL); |
d8a8188d | 654 | if (fp) { |
0bb474a4 | 655 | found = 1; |
a4dc7ff0 | 656 | *val = of_read_ulong(fp, cells); |
10f7e7c1 | 657 | } |
0bb474a4 AB |
658 | |
659 | of_node_put(cpu); | |
10f7e7c1 | 660 | } |
0bb474a4 AB |
661 | |
662 | return found; | |
663 | } | |
664 | ||
665 | void __init generic_calibrate_decr(void) | |
666 | { | |
667 | ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ | |
668 | ||
669 | if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && | |
670 | !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { | |
671 | ||
10f7e7c1 AB |
672 | printk(KERN_ERR "WARNING: Estimating decrementer frequency " |
673 | "(not found)\n"); | |
0bb474a4 | 674 | } |
10f7e7c1 | 675 | |
0bb474a4 AB |
676 | ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ |
677 | ||
678 | if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && | |
679 | !get_freq("clock-frequency", 1, &ppc_proc_freq)) { | |
680 | ||
681 | printk(KERN_ERR "WARNING: Estimating processor frequency " | |
682 | "(not found)\n"); | |
10f7e7c1 | 683 | } |
0bb474a4 | 684 | |
aab69292 | 685 | #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) |
0fd6f717 KG |
686 | /* Set the time base to zero */ |
687 | mtspr(SPRN_TBWL, 0); | |
688 | mtspr(SPRN_TBWU, 0); | |
689 | ||
690 | /* Clear any pending timer interrupts */ | |
691 | mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); | |
692 | ||
693 | /* Enable decrementer interrupt */ | |
694 | mtspr(SPRN_TCR, TCR_DIE); | |
695 | #endif | |
10f7e7c1 | 696 | } |
10f7e7c1 | 697 | |
aa3be5f3 | 698 | int update_persistent_clock(struct timespec now) |
f2783c15 PM |
699 | { |
700 | struct rtc_time tm; | |
701 | ||
aa3be5f3 TB |
702 | if (!ppc_md.set_rtc_time) |
703 | return 0; | |
704 | ||
705 | to_tm(now.tv_sec + 1 + timezone_offset, &tm); | |
706 | tm.tm_year -= 1900; | |
707 | tm.tm_mon -= 1; | |
708 | ||
709 | return ppc_md.set_rtc_time(&tm); | |
710 | } | |
711 | ||
712 | unsigned long read_persistent_clock(void) | |
713 | { | |
714 | struct rtc_time tm; | |
715 | static int first = 1; | |
716 | ||
717 | /* XXX this is a litle fragile but will work okay in the short term */ | |
718 | if (first) { | |
719 | first = 0; | |
720 | if (ppc_md.time_init) | |
721 | timezone_offset = ppc_md.time_init(); | |
722 | ||
723 | /* get_boot_time() isn't guaranteed to be safe to call late */ | |
724 | if (ppc_md.get_boot_time) | |
725 | return ppc_md.get_boot_time() -timezone_offset; | |
726 | } | |
f2783c15 PM |
727 | if (!ppc_md.get_rtc_time) |
728 | return 0; | |
729 | ppc_md.get_rtc_time(&tm); | |
730 | return mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, | |
731 | tm.tm_hour, tm.tm_min, tm.tm_sec); | |
732 | } | |
733 | ||
4a4cfe38 TB |
734 | /* clocksource code */ |
735 | static cycle_t rtc_read(void) | |
736 | { | |
737 | return (cycle_t)get_rtc(); | |
738 | } | |
739 | ||
740 | static cycle_t timebase_read(void) | |
741 | { | |
742 | return (cycle_t)get_tb(); | |
743 | } | |
744 | ||
745 | void update_vsyscall(struct timespec *wall_time, struct clocksource *clock) | |
746 | { | |
747 | u64 t2x, stamp_xsec; | |
748 | ||
749 | if (clock != &clocksource_timebase) | |
750 | return; | |
751 | ||
752 | /* Make userspace gettimeofday spin until we're done. */ | |
753 | ++vdso_data->tb_update_count; | |
754 | smp_mb(); | |
755 | ||
756 | /* XXX this assumes clock->shift == 22 */ | |
757 | /* 4611686018 ~= 2^(20+64-22) / 1e9 */ | |
758 | t2x = (u64) clock->mult * 4611686018ULL; | |
759 | stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC; | |
760 | do_div(stamp_xsec, 1000000000); | |
761 | stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC; | |
762 | update_gtod(clock->cycle_last, stamp_xsec, t2x); | |
763 | } | |
764 | ||
765 | void update_vsyscall_tz(void) | |
766 | { | |
767 | /* Make userspace gettimeofday spin until we're done. */ | |
768 | ++vdso_data->tb_update_count; | |
769 | smp_mb(); | |
770 | vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; | |
771 | vdso_data->tz_dsttime = sys_tz.tz_dsttime; | |
772 | smp_mb(); | |
773 | ++vdso_data->tb_update_count; | |
774 | } | |
775 | ||
776 | void __init clocksource_init(void) | |
777 | { | |
778 | struct clocksource *clock; | |
779 | ||
780 | if (__USE_RTC()) | |
781 | clock = &clocksource_rtc; | |
782 | else | |
783 | clock = &clocksource_timebase; | |
784 | ||
785 | clock->mult = clocksource_hz2mult(tb_ticks_per_sec, clock->shift); | |
786 | ||
787 | if (clocksource_register(clock)) { | |
788 | printk(KERN_ERR "clocksource: %s is already registered\n", | |
789 | clock->name); | |
790 | return; | |
791 | } | |
792 | ||
793 | printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", | |
794 | clock->name, clock->mult, clock->shift); | |
795 | } | |
796 | ||
d831d0b8 TB |
797 | static int decrementer_set_next_event(unsigned long evt, |
798 | struct clock_event_device *dev) | |
799 | { | |
800 | set_dec(evt); | |
801 | return 0; | |
802 | } | |
803 | ||
804 | static void decrementer_set_mode(enum clock_event_mode mode, | |
805 | struct clock_event_device *dev) | |
806 | { | |
807 | if (mode != CLOCK_EVT_MODE_ONESHOT) | |
808 | decrementer_set_next_event(DECREMENTER_MAX, dev); | |
809 | } | |
810 | ||
811 | static void register_decrementer_clockevent(int cpu) | |
812 | { | |
813 | struct clock_event_device *dec = &per_cpu(decrementers, cpu); | |
814 | ||
815 | *dec = decrementer_clockevent; | |
816 | dec->cpumask = cpumask_of_cpu(cpu); | |
817 | ||
818 | printk(KERN_ERR "clockevent: %s mult[%lx] shift[%d] cpu[%d]\n", | |
819 | dec->name, dec->mult, dec->shift, cpu); | |
820 | ||
821 | clockevents_register_device(dec); | |
822 | } | |
823 | ||
824 | void init_decrementer_clockevent(void) | |
825 | { | |
826 | int cpu = smp_processor_id(); | |
827 | ||
828 | decrementer_clockevent.mult = div_sc(ppc_tb_freq, NSEC_PER_SEC, | |
829 | decrementer_clockevent.shift); | |
830 | decrementer_clockevent.max_delta_ns = | |
831 | clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent); | |
832 | decrementer_clockevent.min_delta_ns = 1000; | |
833 | ||
834 | register_decrementer_clockevent(cpu); | |
835 | } | |
836 | ||
837 | void secondary_cpu_time_init(void) | |
838 | { | |
839 | /* FIME: Should make unrelatred change to move snapshot_timebase | |
840 | * call here ! */ | |
841 | register_decrementer_clockevent(smp_processor_id()); | |
842 | } | |
843 | ||
f2783c15 | 844 | /* This function is only called on the boot processor */ |
1da177e4 LT |
845 | void __init time_init(void) |
846 | { | |
1da177e4 | 847 | unsigned long flags; |
1da177e4 | 848 | struct div_result res; |
092b8f34 | 849 | u64 scale, x; |
f2783c15 PM |
850 | unsigned shift; |
851 | ||
96c44507 PM |
852 | if (__USE_RTC()) { |
853 | /* 601 processor: dec counts down by 128 every 128ns */ | |
854 | ppc_tb_freq = 1000000000; | |
eb36c288 | 855 | tb_last_jiffy = get_rtcl(); |
96c44507 PM |
856 | } else { |
857 | /* Normal PowerPC with timebase register */ | |
858 | ppc_md.calibrate_decr(); | |
224ad80a | 859 | printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", |
96c44507 | 860 | ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); |
224ad80a | 861 | printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", |
96c44507 | 862 | ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); |
eb36c288 | 863 | tb_last_jiffy = get_tb(); |
96c44507 | 864 | } |
374e99d4 PM |
865 | |
866 | tb_ticks_per_jiffy = ppc_tb_freq / HZ; | |
092b8f34 | 867 | tb_ticks_per_sec = ppc_tb_freq; |
374e99d4 PM |
868 | tb_ticks_per_usec = ppc_tb_freq / 1000000; |
869 | tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000); | |
c6622f63 | 870 | calc_cputime_factors(); |
092b8f34 PM |
871 | |
872 | /* | |
873 | * Calculate the length of each tick in ns. It will not be | |
874 | * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ. | |
875 | * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq, | |
876 | * rounded up. | |
877 | */ | |
878 | x = (u64) NSEC_PER_SEC * tb_ticks_per_jiffy + ppc_tb_freq - 1; | |
879 | do_div(x, ppc_tb_freq); | |
880 | tick_nsec = x; | |
881 | last_tick_len = x << TICKLEN_SCALE; | |
882 | ||
883 | /* | |
884 | * Compute ticklen_to_xs, which is a factor which gets multiplied | |
885 | * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value. | |
886 | * It is computed as: | |
887 | * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9) | |
888 | * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT | |
0a45d449 PM |
889 | * which turns out to be N = 51 - SHIFT_HZ. |
890 | * This gives the result as a 0.64 fixed-point fraction. | |
891 | * That value is reduced by an offset amounting to 1 xsec per | |
892 | * 2^31 timebase ticks to avoid problems with time going backwards | |
893 | * by 1 xsec when we do timer_recalc_offset due to losing the | |
894 | * fractional xsec. That offset is equal to ppc_tb_freq/2^51 | |
895 | * since there are 2^20 xsec in a second. | |
092b8f34 | 896 | */ |
0a45d449 PM |
897 | div128_by_32((1ULL << 51) - ppc_tb_freq, 0, |
898 | tb_ticks_per_jiffy << SHIFT_HZ, &res); | |
092b8f34 PM |
899 | div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res); |
900 | ticklen_to_xs = res.result_low; | |
901 | ||
902 | /* Compute tb_to_xs from tick_nsec */ | |
903 | tb_to_xs = mulhdu(last_tick_len << TICKLEN_SHIFT, ticklen_to_xs); | |
374e99d4 | 904 | |
1da177e4 LT |
905 | /* |
906 | * Compute scale factor for sched_clock. | |
907 | * The calibrate_decr() function has set tb_ticks_per_sec, | |
908 | * which is the timebase frequency. | |
909 | * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret | |
910 | * the 128-bit result as a 64.64 fixed-point number. | |
911 | * We then shift that number right until it is less than 1.0, | |
912 | * giving us the scale factor and shift count to use in | |
913 | * sched_clock(). | |
914 | */ | |
915 | div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); | |
916 | scale = res.result_low; | |
917 | for (shift = 0; res.result_high != 0; ++shift) { | |
918 | scale = (scale >> 1) | (res.result_high << 63); | |
919 | res.result_high >>= 1; | |
920 | } | |
921 | tb_to_ns_scale = scale; | |
922 | tb_to_ns_shift = shift; | |
fc9069fe | 923 | /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ |
c27da339 | 924 | boot_tb = get_tb_or_rtc(); |
1da177e4 | 925 | |
1da177e4 | 926 | write_seqlock_irqsave(&xtime_lock, flags); |
092b8f34 PM |
927 | |
928 | /* If platform provided a timezone (pmac), we correct the time */ | |
929 | if (timezone_offset) { | |
930 | sys_tz.tz_minuteswest = -timezone_offset / 60; | |
931 | sys_tz.tz_dsttime = 0; | |
092b8f34 PM |
932 | } |
933 | ||
1da177e4 LT |
934 | do_gtod.varp = &do_gtod.vars[0]; |
935 | do_gtod.var_idx = 0; | |
96c44507 | 936 | do_gtod.varp->tb_orig_stamp = tb_last_jiffy; |
eb36c288 | 937 | __get_cpu_var(last_jiffy) = tb_last_jiffy; |
f2783c15 | 938 | do_gtod.varp->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC; |
1da177e4 LT |
939 | do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; |
940 | do_gtod.varp->tb_to_xs = tb_to_xs; | |
941 | do_gtod.tb_to_us = tb_to_us; | |
a7f290da BH |
942 | |
943 | vdso_data->tb_orig_stamp = tb_last_jiffy; | |
944 | vdso_data->tb_update_count = 0; | |
945 | vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; | |
092b8f34 | 946 | vdso_data->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC; |
a7f290da | 947 | vdso_data->tb_to_xs = tb_to_xs; |
1da177e4 LT |
948 | |
949 | time_freq = 0; | |
950 | ||
1da177e4 LT |
951 | write_sequnlock_irqrestore(&xtime_lock, flags); |
952 | ||
4a4cfe38 TB |
953 | /* Register the clocksource, if we're not running on iSeries */ |
954 | if (!firmware_has_feature(FW_FEATURE_ISERIES)) | |
955 | clocksource_init(); | |
956 | ||
d831d0b8 | 957 | init_decrementer_clockevent(); |
1da177e4 LT |
958 | } |
959 | ||
1da177e4 | 960 | |
1da177e4 LT |
961 | #define FEBRUARY 2 |
962 | #define STARTOFTIME 1970 | |
963 | #define SECDAY 86400L | |
964 | #define SECYR (SECDAY * 365) | |
f2783c15 PM |
965 | #define leapyear(year) ((year) % 4 == 0 && \ |
966 | ((year) % 100 != 0 || (year) % 400 == 0)) | |
1da177e4 LT |
967 | #define days_in_year(a) (leapyear(a) ? 366 : 365) |
968 | #define days_in_month(a) (month_days[(a) - 1]) | |
969 | ||
970 | static int month_days[12] = { | |
971 | 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 | |
972 | }; | |
973 | ||
974 | /* | |
975 | * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) | |
976 | */ | |
977 | void GregorianDay(struct rtc_time * tm) | |
978 | { | |
979 | int leapsToDate; | |
980 | int lastYear; | |
981 | int day; | |
982 | int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; | |
983 | ||
f2783c15 | 984 | lastYear = tm->tm_year - 1; |
1da177e4 LT |
985 | |
986 | /* | |
987 | * Number of leap corrections to apply up to end of last year | |
988 | */ | |
f2783c15 | 989 | leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400; |
1da177e4 LT |
990 | |
991 | /* | |
992 | * This year is a leap year if it is divisible by 4 except when it is | |
993 | * divisible by 100 unless it is divisible by 400 | |
994 | * | |
f2783c15 | 995 | * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was |
1da177e4 | 996 | */ |
f2783c15 | 997 | day = tm->tm_mon > 2 && leapyear(tm->tm_year); |
1da177e4 LT |
998 | |
999 | day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + | |
1000 | tm->tm_mday; | |
1001 | ||
f2783c15 | 1002 | tm->tm_wday = day % 7; |
1da177e4 LT |
1003 | } |
1004 | ||
1005 | void to_tm(int tim, struct rtc_time * tm) | |
1006 | { | |
1007 | register int i; | |
1008 | register long hms, day; | |
1009 | ||
1010 | day = tim / SECDAY; | |
1011 | hms = tim % SECDAY; | |
1012 | ||
1013 | /* Hours, minutes, seconds are easy */ | |
1014 | tm->tm_hour = hms / 3600; | |
1015 | tm->tm_min = (hms % 3600) / 60; | |
1016 | tm->tm_sec = (hms % 3600) % 60; | |
1017 | ||
1018 | /* Number of years in days */ | |
1019 | for (i = STARTOFTIME; day >= days_in_year(i); i++) | |
1020 | day -= days_in_year(i); | |
1021 | tm->tm_year = i; | |
1022 | ||
1023 | /* Number of months in days left */ | |
1024 | if (leapyear(tm->tm_year)) | |
1025 | days_in_month(FEBRUARY) = 29; | |
1026 | for (i = 1; day >= days_in_month(i); i++) | |
1027 | day -= days_in_month(i); | |
1028 | days_in_month(FEBRUARY) = 28; | |
1029 | tm->tm_mon = i; | |
1030 | ||
1031 | /* Days are what is left over (+1) from all that. */ | |
1032 | tm->tm_mday = day + 1; | |
1033 | ||
1034 | /* | |
1035 | * Determine the day of week | |
1036 | */ | |
1037 | GregorianDay(tm); | |
1038 | } | |
1039 | ||
1040 | /* Auxiliary function to compute scaling factors */ | |
1041 | /* Actually the choice of a timebase running at 1/4 the of the bus | |
1042 | * frequency giving resolution of a few tens of nanoseconds is quite nice. | |
1043 | * It makes this computation very precise (27-28 bits typically) which | |
1044 | * is optimistic considering the stability of most processor clock | |
1045 | * oscillators and the precision with which the timebase frequency | |
1046 | * is measured but does not harm. | |
1047 | */ | |
f2783c15 PM |
1048 | unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale) |
1049 | { | |
1da177e4 LT |
1050 | unsigned mlt=0, tmp, err; |
1051 | /* No concern for performance, it's done once: use a stupid | |
1052 | * but safe and compact method to find the multiplier. | |
1053 | */ | |
1054 | ||
1055 | for (tmp = 1U<<31; tmp != 0; tmp >>= 1) { | |
f2783c15 PM |
1056 | if (mulhwu(inscale, mlt|tmp) < outscale) |
1057 | mlt |= tmp; | |
1da177e4 LT |
1058 | } |
1059 | ||
1060 | /* We might still be off by 1 for the best approximation. | |
1061 | * A side effect of this is that if outscale is too large | |
1062 | * the returned value will be zero. | |
1063 | * Many corner cases have been checked and seem to work, | |
1064 | * some might have been forgotten in the test however. | |
1065 | */ | |
1066 | ||
f2783c15 PM |
1067 | err = inscale * (mlt+1); |
1068 | if (err <= inscale/2) | |
1069 | mlt++; | |
1da177e4 | 1070 | return mlt; |
f2783c15 | 1071 | } |
1da177e4 LT |
1072 | |
1073 | /* | |
1074 | * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit | |
1075 | * result. | |
1076 | */ | |
f2783c15 PM |
1077 | void div128_by_32(u64 dividend_high, u64 dividend_low, |
1078 | unsigned divisor, struct div_result *dr) | |
1da177e4 | 1079 | { |
f2783c15 PM |
1080 | unsigned long a, b, c, d; |
1081 | unsigned long w, x, y, z; | |
1082 | u64 ra, rb, rc; | |
1da177e4 LT |
1083 | |
1084 | a = dividend_high >> 32; | |
1085 | b = dividend_high & 0xffffffff; | |
1086 | c = dividend_low >> 32; | |
1087 | d = dividend_low & 0xffffffff; | |
1088 | ||
f2783c15 PM |
1089 | w = a / divisor; |
1090 | ra = ((u64)(a - (w * divisor)) << 32) + b; | |
1091 | ||
f2783c15 PM |
1092 | rb = ((u64) do_div(ra, divisor) << 32) + c; |
1093 | x = ra; | |
1da177e4 | 1094 | |
f2783c15 PM |
1095 | rc = ((u64) do_div(rb, divisor) << 32) + d; |
1096 | y = rb; | |
1097 | ||
1098 | do_div(rc, divisor); | |
1099 | z = rc; | |
1da177e4 | 1100 | |
f2783c15 PM |
1101 | dr->result_high = ((u64)w << 32) + x; |
1102 | dr->result_low = ((u64)y << 32) + z; | |
1da177e4 LT |
1103 | |
1104 | } |