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1da177e4 LT |
1 | /* |
2 | * | |
3 | * Common time routines among all ppc machines. | |
4 | * | |
5 | * Written by Cort Dougan (cort@cs.nmt.edu) to merge | |
6 | * Paul Mackerras' version and mine for PReP and Pmac. | |
7 | * MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net). | |
8 | * Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com) | |
9 | * | |
10 | * First round of bugfixes by Gabriel Paubert (paubert@iram.es) | |
11 | * to make clock more stable (2.4.0-test5). The only thing | |
12 | * that this code assumes is that the timebases have been synchronized | |
13 | * by firmware on SMP and are never stopped (never do sleep | |
14 | * on SMP then, nap and doze are OK). | |
15 | * | |
16 | * Speeded up do_gettimeofday by getting rid of references to | |
17 | * xtime (which required locks for consistency). (mikejc@us.ibm.com) | |
18 | * | |
19 | * TODO (not necessarily in this file): | |
20 | * - improve precision and reproducibility of timebase frequency | |
21 | * measurement at boot time. (for iSeries, we calibrate the timebase | |
22 | * against the Titan chip's clock.) | |
23 | * - for astronomical applications: add a new function to get | |
24 | * non ambiguous timestamps even around leap seconds. This needs | |
25 | * a new timestamp format and a good name. | |
26 | * | |
27 | * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 | |
28 | * "A Kernel Model for Precision Timekeeping" by Dave Mills | |
29 | * | |
30 | * This program is free software; you can redistribute it and/or | |
31 | * modify it under the terms of the GNU General Public License | |
32 | * as published by the Free Software Foundation; either version | |
33 | * 2 of the License, or (at your option) any later version. | |
34 | */ | |
35 | ||
36 | #include <linux/config.h> | |
37 | #include <linux/errno.h> | |
38 | #include <linux/module.h> | |
39 | #include <linux/sched.h> | |
40 | #include <linux/kernel.h> | |
41 | #include <linux/param.h> | |
42 | #include <linux/string.h> | |
43 | #include <linux/mm.h> | |
44 | #include <linux/interrupt.h> | |
45 | #include <linux/timex.h> | |
46 | #include <linux/kernel_stat.h> | |
47 | #include <linux/mc146818rtc.h> | |
48 | #include <linux/time.h> | |
49 | #include <linux/init.h> | |
50 | #include <linux/profile.h> | |
51 | #include <linux/cpu.h> | |
52 | #include <linux/security.h> | |
53 | ||
1da177e4 LT |
54 | #include <asm/io.h> |
55 | #include <asm/processor.h> | |
56 | #include <asm/nvram.h> | |
57 | #include <asm/cache.h> | |
58 | #include <asm/machdep.h> | |
59 | #ifdef CONFIG_PPC_ISERIES | |
60 | #include <asm/iSeries/ItLpQueue.h> | |
61 | #include <asm/iSeries/HvCallXm.h> | |
62 | #endif | |
63 | #include <asm/uaccess.h> | |
64 | #include <asm/time.h> | |
65 | #include <asm/ppcdebug.h> | |
66 | #include <asm/prom.h> | |
67 | #include <asm/sections.h> | |
68 | #include <asm/systemcfg.h> | |
1ababe11 | 69 | #include <asm/firmware.h> |
1da177e4 LT |
70 | |
71 | u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES; | |
72 | ||
73 | EXPORT_SYMBOL(jiffies_64); | |
74 | ||
75 | /* keep track of when we need to update the rtc */ | |
76 | time_t last_rtc_update; | |
77 | extern int piranha_simulator; | |
78 | #ifdef CONFIG_PPC_ISERIES | |
79 | unsigned long iSeries_recal_titan = 0; | |
80 | unsigned long iSeries_recal_tb = 0; | |
81 | static unsigned long first_settimeofday = 1; | |
82 | #endif | |
83 | ||
84 | #define XSEC_PER_SEC (1024*1024) | |
85 | ||
86 | unsigned long tb_ticks_per_jiffy; | |
87 | unsigned long tb_ticks_per_usec = 100; /* sane default */ | |
88 | EXPORT_SYMBOL(tb_ticks_per_usec); | |
89 | unsigned long tb_ticks_per_sec; | |
90 | unsigned long tb_to_xs; | |
91 | unsigned tb_to_us; | |
92 | unsigned long processor_freq; | |
93 | DEFINE_SPINLOCK(rtc_lock); | |
6ae3db11 | 94 | EXPORT_SYMBOL_GPL(rtc_lock); |
1da177e4 LT |
95 | |
96 | unsigned long tb_to_ns_scale; | |
97 | unsigned long tb_to_ns_shift; | |
98 | ||
99 | struct gettimeofday_struct do_gtod; | |
100 | ||
101 | extern unsigned long wall_jiffies; | |
1da177e4 LT |
102 | extern int smp_tb_synchronized; |
103 | ||
104 | extern struct timezone sys_tz; | |
105 | ||
106 | void ppc_adjtimex(void); | |
107 | ||
108 | static unsigned adjusting_time = 0; | |
109 | ||
10f7e7c1 AB |
110 | unsigned long ppc_proc_freq; |
111 | unsigned long ppc_tb_freq; | |
112 | ||
1da177e4 LT |
113 | static __inline__ void timer_check_rtc(void) |
114 | { | |
115 | /* | |
116 | * update the rtc when needed, this should be performed on the | |
117 | * right fraction of a second. Half or full second ? | |
118 | * Full second works on mk48t59 clocks, others need testing. | |
119 | * Note that this update is basically only used through | |
120 | * the adjtimex system calls. Setting the HW clock in | |
121 | * any other way is a /dev/rtc and userland business. | |
122 | * This is still wrong by -0.5/+1.5 jiffies because of the | |
123 | * timer interrupt resolution and possible delay, but here we | |
124 | * hit a quantization limit which can only be solved by higher | |
125 | * resolution timers and decoupling time management from timer | |
126 | * interrupts. This is also wrong on the clocks | |
127 | * which require being written at the half second boundary. | |
128 | * We should have an rtc call that only sets the minutes and | |
129 | * seconds like on Intel to avoid problems with non UTC clocks. | |
130 | */ | |
131 | if ( (time_status & STA_UNSYNC) == 0 && | |
132 | xtime.tv_sec - last_rtc_update >= 659 && | |
133 | abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ && | |
134 | jiffies - wall_jiffies == 1) { | |
135 | struct rtc_time tm; | |
136 | to_tm(xtime.tv_sec+1, &tm); | |
137 | tm.tm_year -= 1900; | |
138 | tm.tm_mon -= 1; | |
139 | if (ppc_md.set_rtc_time(&tm) == 0) | |
140 | last_rtc_update = xtime.tv_sec+1; | |
141 | else | |
142 | /* Try again one minute later */ | |
143 | last_rtc_update += 60; | |
144 | } | |
145 | } | |
146 | ||
147 | /* | |
148 | * This version of gettimeofday has microsecond resolution. | |
149 | */ | |
150 | static inline void __do_gettimeofday(struct timeval *tv, unsigned long tb_val) | |
151 | { | |
152 | unsigned long sec, usec, tb_ticks; | |
153 | unsigned long xsec, tb_xsec; | |
154 | struct gettimeofday_vars * temp_varp; | |
155 | unsigned long temp_tb_to_xs, temp_stamp_xsec; | |
156 | ||
157 | /* | |
158 | * These calculations are faster (gets rid of divides) | |
159 | * if done in units of 1/2^20 rather than microseconds. | |
160 | * The conversion to microseconds at the end is done | |
161 | * without a divide (and in fact, without a multiply) | |
162 | */ | |
163 | temp_varp = do_gtod.varp; | |
164 | tb_ticks = tb_val - temp_varp->tb_orig_stamp; | |
165 | temp_tb_to_xs = temp_varp->tb_to_xs; | |
166 | temp_stamp_xsec = temp_varp->stamp_xsec; | |
167 | tb_xsec = mulhdu( tb_ticks, temp_tb_to_xs ); | |
168 | xsec = temp_stamp_xsec + tb_xsec; | |
169 | sec = xsec / XSEC_PER_SEC; | |
170 | xsec -= sec * XSEC_PER_SEC; | |
171 | usec = (xsec * USEC_PER_SEC)/XSEC_PER_SEC; | |
172 | ||
173 | tv->tv_sec = sec; | |
174 | tv->tv_usec = usec; | |
175 | } | |
176 | ||
177 | void do_gettimeofday(struct timeval *tv) | |
178 | { | |
179 | __do_gettimeofday(tv, get_tb()); | |
180 | } | |
181 | ||
182 | EXPORT_SYMBOL(do_gettimeofday); | |
183 | ||
184 | /* Synchronize xtime with do_gettimeofday */ | |
185 | ||
186 | static inline void timer_sync_xtime(unsigned long cur_tb) | |
187 | { | |
188 | struct timeval my_tv; | |
189 | ||
190 | __do_gettimeofday(&my_tv, cur_tb); | |
191 | ||
192 | if (xtime.tv_sec <= my_tv.tv_sec) { | |
193 | xtime.tv_sec = my_tv.tv_sec; | |
194 | xtime.tv_nsec = my_tv.tv_usec * 1000; | |
195 | } | |
196 | } | |
197 | ||
198 | /* | |
199 | * When the timebase - tb_orig_stamp gets too big, we do a manipulation | |
200 | * between tb_orig_stamp and stamp_xsec. The goal here is to keep the | |
201 | * difference tb - tb_orig_stamp small enough to always fit inside a | |
202 | * 32 bits number. This is a requirement of our fast 32 bits userland | |
203 | * implementation in the vdso. If we "miss" a call to this function | |
204 | * (interrupt latency, CPU locked in a spinlock, ...) and we end up | |
205 | * with a too big difference, then the vdso will fallback to calling | |
206 | * the syscall | |
207 | */ | |
208 | static __inline__ void timer_recalc_offset(unsigned long cur_tb) | |
209 | { | |
210 | struct gettimeofday_vars * temp_varp; | |
211 | unsigned temp_idx; | |
212 | unsigned long offset, new_stamp_xsec, new_tb_orig_stamp; | |
213 | ||
214 | if (((cur_tb - do_gtod.varp->tb_orig_stamp) & 0x80000000u) == 0) | |
215 | return; | |
216 | ||
217 | temp_idx = (do_gtod.var_idx == 0); | |
218 | temp_varp = &do_gtod.vars[temp_idx]; | |
219 | ||
220 | new_tb_orig_stamp = cur_tb; | |
221 | offset = new_tb_orig_stamp - do_gtod.varp->tb_orig_stamp; | |
222 | new_stamp_xsec = do_gtod.varp->stamp_xsec + mulhdu(offset, do_gtod.varp->tb_to_xs); | |
223 | ||
224 | temp_varp->tb_to_xs = do_gtod.varp->tb_to_xs; | |
225 | temp_varp->tb_orig_stamp = new_tb_orig_stamp; | |
226 | temp_varp->stamp_xsec = new_stamp_xsec; | |
0d8d4d42 | 227 | smp_mb(); |
1da177e4 LT |
228 | do_gtod.varp = temp_varp; |
229 | do_gtod.var_idx = temp_idx; | |
230 | ||
231 | ++(systemcfg->tb_update_count); | |
0d8d4d42 | 232 | smp_wmb(); |
1da177e4 LT |
233 | systemcfg->tb_orig_stamp = new_tb_orig_stamp; |
234 | systemcfg->stamp_xsec = new_stamp_xsec; | |
0d8d4d42 | 235 | smp_wmb(); |
1da177e4 LT |
236 | ++(systemcfg->tb_update_count); |
237 | } | |
238 | ||
239 | #ifdef CONFIG_SMP | |
240 | unsigned long profile_pc(struct pt_regs *regs) | |
241 | { | |
242 | unsigned long pc = instruction_pointer(regs); | |
243 | ||
244 | if (in_lock_functions(pc)) | |
245 | return regs->link; | |
246 | ||
247 | return pc; | |
248 | } | |
249 | EXPORT_SYMBOL(profile_pc); | |
250 | #endif | |
251 | ||
252 | #ifdef CONFIG_PPC_ISERIES | |
253 | ||
254 | /* | |
255 | * This function recalibrates the timebase based on the 49-bit time-of-day | |
256 | * value in the Titan chip. The Titan is much more accurate than the value | |
257 | * returned by the service processor for the timebase frequency. | |
258 | */ | |
259 | ||
260 | static void iSeries_tb_recal(void) | |
261 | { | |
262 | struct div_result divres; | |
263 | unsigned long titan, tb; | |
264 | tb = get_tb(); | |
265 | titan = HvCallXm_loadTod(); | |
266 | if ( iSeries_recal_titan ) { | |
267 | unsigned long tb_ticks = tb - iSeries_recal_tb; | |
268 | unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12; | |
269 | unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec; | |
270 | unsigned long new_tb_ticks_per_jiffy = (new_tb_ticks_per_sec+(HZ/2))/HZ; | |
271 | long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy; | |
272 | char sign = '+'; | |
273 | /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */ | |
274 | new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ; | |
275 | ||
276 | if ( tick_diff < 0 ) { | |
277 | tick_diff = -tick_diff; | |
278 | sign = '-'; | |
279 | } | |
280 | if ( tick_diff ) { | |
281 | if ( tick_diff < tb_ticks_per_jiffy/25 ) { | |
282 | printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n", | |
283 | new_tb_ticks_per_jiffy, sign, tick_diff ); | |
284 | tb_ticks_per_jiffy = new_tb_ticks_per_jiffy; | |
285 | tb_ticks_per_sec = new_tb_ticks_per_sec; | |
286 | div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres ); | |
287 | do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; | |
288 | tb_to_xs = divres.result_low; | |
289 | do_gtod.varp->tb_to_xs = tb_to_xs; | |
290 | systemcfg->tb_ticks_per_sec = tb_ticks_per_sec; | |
291 | systemcfg->tb_to_xs = tb_to_xs; | |
292 | } | |
293 | else { | |
294 | printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" | |
295 | " new tb_ticks_per_jiffy = %lu\n" | |
296 | " old tb_ticks_per_jiffy = %lu\n", | |
297 | new_tb_ticks_per_jiffy, tb_ticks_per_jiffy ); | |
298 | } | |
299 | } | |
300 | } | |
301 | iSeries_recal_titan = titan; | |
302 | iSeries_recal_tb = tb; | |
303 | } | |
304 | #endif | |
305 | ||
306 | /* | |
307 | * For iSeries shared processors, we have to let the hypervisor | |
308 | * set the hardware decrementer. We set a virtual decrementer | |
309 | * in the lppaca and call the hypervisor if the virtual | |
310 | * decrementer is less than the current value in the hardware | |
311 | * decrementer. (almost always the new decrementer value will | |
312 | * be greater than the current hardware decementer so the hypervisor | |
313 | * call will not be needed) | |
314 | */ | |
315 | ||
316 | unsigned long tb_last_stamp __cacheline_aligned_in_smp; | |
317 | ||
318 | /* | |
319 | * timer_interrupt - gets called when the decrementer overflows, | |
320 | * with interrupts disabled. | |
321 | */ | |
322 | int timer_interrupt(struct pt_regs * regs) | |
323 | { | |
324 | int next_dec; | |
325 | unsigned long cur_tb; | |
326 | struct paca_struct *lpaca = get_paca(); | |
327 | unsigned long cpu = smp_processor_id(); | |
328 | ||
329 | irq_enter(); | |
330 | ||
1da177e4 | 331 | profile_tick(CPU_PROFILING, regs); |
1da177e4 LT |
332 | |
333 | lpaca->lppaca.int_dword.fields.decr_int = 0; | |
334 | ||
335 | while (lpaca->next_jiffy_update_tb <= (cur_tb = get_tb())) { | |
336 | /* | |
337 | * We cannot disable the decrementer, so in the period | |
338 | * between this cpu's being marked offline in cpu_online_map | |
339 | * and calling stop-self, it is taking timer interrupts. | |
340 | * Avoid calling into the scheduler rebalancing code if this | |
341 | * is the case. | |
342 | */ | |
343 | if (!cpu_is_offline(cpu)) | |
344 | update_process_times(user_mode(regs)); | |
345 | /* | |
346 | * No need to check whether cpu is offline here; boot_cpuid | |
347 | * should have been fixed up by now. | |
348 | */ | |
349 | if (cpu == boot_cpuid) { | |
350 | write_seqlock(&xtime_lock); | |
351 | tb_last_stamp = lpaca->next_jiffy_update_tb; | |
352 | timer_recalc_offset(lpaca->next_jiffy_update_tb); | |
353 | do_timer(regs); | |
354 | timer_sync_xtime(lpaca->next_jiffy_update_tb); | |
355 | timer_check_rtc(); | |
356 | write_sequnlock(&xtime_lock); | |
357 | if ( adjusting_time && (time_adjust == 0) ) | |
358 | ppc_adjtimex(); | |
359 | } | |
360 | lpaca->next_jiffy_update_tb += tb_ticks_per_jiffy; | |
361 | } | |
362 | ||
363 | next_dec = lpaca->next_jiffy_update_tb - cur_tb; | |
364 | if (next_dec > lpaca->default_decr) | |
365 | next_dec = lpaca->default_decr; | |
366 | set_dec(next_dec); | |
367 | ||
368 | #ifdef CONFIG_PPC_ISERIES | |
937b31b1 | 369 | if (hvlpevent_is_pending()) |
74889802 | 370 | process_hvlpevents(regs); |
1da177e4 LT |
371 | #endif |
372 | ||
8d15a3e5 | 373 | /* collect purr register values often, for accurate calculations */ |
1ababe11 | 374 | if (firmware_has_feature(FW_FEATURE_SPLPAR)) { |
1da177e4 LT |
375 | struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); |
376 | cu->current_tb = mfspr(SPRN_PURR); | |
377 | } | |
1da177e4 LT |
378 | |
379 | irq_exit(); | |
380 | ||
381 | return 1; | |
382 | } | |
383 | ||
384 | /* | |
385 | * Scheduler clock - returns current time in nanosec units. | |
386 | * | |
387 | * Note: mulhdu(a, b) (multiply high double unsigned) returns | |
388 | * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b | |
389 | * are 64-bit unsigned numbers. | |
390 | */ | |
391 | unsigned long long sched_clock(void) | |
392 | { | |
393 | return mulhdu(get_tb(), tb_to_ns_scale) << tb_to_ns_shift; | |
394 | } | |
395 | ||
396 | int do_settimeofday(struct timespec *tv) | |
397 | { | |
398 | time_t wtm_sec, new_sec = tv->tv_sec; | |
399 | long wtm_nsec, new_nsec = tv->tv_nsec; | |
400 | unsigned long flags; | |
401 | unsigned long delta_xsec; | |
402 | long int tb_delta; | |
403 | unsigned long new_xsec; | |
404 | ||
405 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
406 | return -EINVAL; | |
407 | ||
408 | write_seqlock_irqsave(&xtime_lock, flags); | |
409 | /* Updating the RTC is not the job of this code. If the time is | |
410 | * stepped under NTP, the RTC will be update after STA_UNSYNC | |
411 | * is cleared. Tool like clock/hwclock either copy the RTC | |
412 | * to the system time, in which case there is no point in writing | |
413 | * to the RTC again, or write to the RTC but then they don't call | |
414 | * settimeofday to perform this operation. | |
415 | */ | |
416 | #ifdef CONFIG_PPC_ISERIES | |
417 | if ( first_settimeofday ) { | |
418 | iSeries_tb_recal(); | |
419 | first_settimeofday = 0; | |
420 | } | |
421 | #endif | |
422 | tb_delta = tb_ticks_since(tb_last_stamp); | |
423 | tb_delta += (jiffies - wall_jiffies) * tb_ticks_per_jiffy; | |
424 | ||
425 | new_nsec -= tb_delta / tb_ticks_per_usec / 1000; | |
426 | ||
427 | wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - new_sec); | |
428 | wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - new_nsec); | |
429 | ||
430 | set_normalized_timespec(&xtime, new_sec, new_nsec); | |
431 | set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); | |
432 | ||
433 | /* In case of a large backwards jump in time with NTP, we want the | |
434 | * clock to be updated as soon as the PLL is again in lock. | |
435 | */ | |
436 | last_rtc_update = new_sec - 658; | |
437 | ||
438 | time_adjust = 0; /* stop active adjtime() */ | |
439 | time_status |= STA_UNSYNC; | |
440 | time_maxerror = NTP_PHASE_LIMIT; | |
441 | time_esterror = NTP_PHASE_LIMIT; | |
442 | ||
443 | delta_xsec = mulhdu( (tb_last_stamp-do_gtod.varp->tb_orig_stamp), | |
444 | do_gtod.varp->tb_to_xs ); | |
445 | ||
446 | new_xsec = (new_nsec * XSEC_PER_SEC) / NSEC_PER_SEC; | |
447 | new_xsec += new_sec * XSEC_PER_SEC; | |
448 | if ( new_xsec > delta_xsec ) { | |
449 | do_gtod.varp->stamp_xsec = new_xsec - delta_xsec; | |
450 | systemcfg->stamp_xsec = new_xsec - delta_xsec; | |
451 | } | |
452 | else { | |
453 | /* This is only for the case where the user is setting the time | |
454 | * way back to a time such that the boot time would have been | |
455 | * before 1970 ... eg. we booted ten days ago, and we are setting | |
456 | * the time to Jan 5, 1970 */ | |
457 | do_gtod.varp->stamp_xsec = new_xsec; | |
458 | do_gtod.varp->tb_orig_stamp = tb_last_stamp; | |
459 | systemcfg->stamp_xsec = new_xsec; | |
460 | systemcfg->tb_orig_stamp = tb_last_stamp; | |
461 | } | |
462 | ||
463 | systemcfg->tz_minuteswest = sys_tz.tz_minuteswest; | |
464 | systemcfg->tz_dsttime = sys_tz.tz_dsttime; | |
465 | ||
466 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
467 | clock_was_set(); | |
468 | return 0; | |
469 | } | |
470 | ||
471 | EXPORT_SYMBOL(do_settimeofday); | |
472 | ||
10f7e7c1 AB |
473 | #if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_MAPLE) || defined(CONFIG_PPC_BPA) |
474 | void __init generic_calibrate_decr(void) | |
475 | { | |
476 | struct device_node *cpu; | |
477 | struct div_result divres; | |
478 | unsigned int *fp; | |
479 | int node_found; | |
480 | ||
481 | /* | |
482 | * The cpu node should have a timebase-frequency property | |
483 | * to tell us the rate at which the decrementer counts. | |
484 | */ | |
485 | cpu = of_find_node_by_type(NULL, "cpu"); | |
486 | ||
487 | ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ | |
488 | node_found = 0; | |
489 | if (cpu != 0) { | |
490 | fp = (unsigned int *)get_property(cpu, "timebase-frequency", | |
491 | NULL); | |
492 | if (fp != 0) { | |
493 | node_found = 1; | |
494 | ppc_tb_freq = *fp; | |
495 | } | |
496 | } | |
497 | if (!node_found) | |
498 | printk(KERN_ERR "WARNING: Estimating decrementer frequency " | |
499 | "(not found)\n"); | |
500 | ||
501 | ppc_proc_freq = DEFAULT_PROC_FREQ; | |
502 | node_found = 0; | |
503 | if (cpu != 0) { | |
504 | fp = (unsigned int *)get_property(cpu, "clock-frequency", | |
505 | NULL); | |
506 | if (fp != 0) { | |
507 | node_found = 1; | |
508 | ppc_proc_freq = *fp; | |
509 | } | |
510 | } | |
511 | if (!node_found) | |
512 | printk(KERN_ERR "WARNING: Estimating processor frequency " | |
513 | "(not found)\n"); | |
514 | ||
515 | of_node_put(cpu); | |
516 | ||
517 | printk(KERN_INFO "time_init: decrementer frequency = %lu.%.6lu MHz\n", | |
518 | ppc_tb_freq/1000000, ppc_tb_freq%1000000); | |
519 | printk(KERN_INFO "time_init: processor frequency = %lu.%.6lu MHz\n", | |
520 | ppc_proc_freq/1000000, ppc_proc_freq%1000000); | |
521 | ||
522 | tb_ticks_per_jiffy = ppc_tb_freq / HZ; | |
523 | tb_ticks_per_sec = tb_ticks_per_jiffy * HZ; | |
524 | tb_ticks_per_usec = ppc_tb_freq / 1000000; | |
525 | tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000); | |
526 | div128_by_32(1024*1024, 0, tb_ticks_per_sec, &divres); | |
527 | tb_to_xs = divres.result_low; | |
528 | ||
529 | setup_default_decr(); | |
530 | } | |
531 | #endif | |
532 | ||
1da177e4 LT |
533 | void __init time_init(void) |
534 | { | |
535 | /* This function is only called on the boot processor */ | |
536 | unsigned long flags; | |
537 | struct rtc_time tm; | |
538 | struct div_result res; | |
539 | unsigned long scale, shift; | |
540 | ||
541 | ppc_md.calibrate_decr(); | |
542 | ||
543 | /* | |
544 | * Compute scale factor for sched_clock. | |
545 | * The calibrate_decr() function has set tb_ticks_per_sec, | |
546 | * which is the timebase frequency. | |
547 | * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret | |
548 | * the 128-bit result as a 64.64 fixed-point number. | |
549 | * We then shift that number right until it is less than 1.0, | |
550 | * giving us the scale factor and shift count to use in | |
551 | * sched_clock(). | |
552 | */ | |
553 | div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); | |
554 | scale = res.result_low; | |
555 | for (shift = 0; res.result_high != 0; ++shift) { | |
556 | scale = (scale >> 1) | (res.result_high << 63); | |
557 | res.result_high >>= 1; | |
558 | } | |
559 | tb_to_ns_scale = scale; | |
560 | tb_to_ns_shift = shift; | |
561 | ||
562 | #ifdef CONFIG_PPC_ISERIES | |
563 | if (!piranha_simulator) | |
564 | #endif | |
565 | ppc_md.get_boot_time(&tm); | |
566 | ||
567 | write_seqlock_irqsave(&xtime_lock, flags); | |
568 | xtime.tv_sec = mktime(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, | |
569 | tm.tm_hour, tm.tm_min, tm.tm_sec); | |
570 | tb_last_stamp = get_tb(); | |
571 | do_gtod.varp = &do_gtod.vars[0]; | |
572 | do_gtod.var_idx = 0; | |
573 | do_gtod.varp->tb_orig_stamp = tb_last_stamp; | |
8f80e5c9 | 574 | get_paca()->next_jiffy_update_tb = tb_last_stamp + tb_ticks_per_jiffy; |
1da177e4 LT |
575 | do_gtod.varp->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC; |
576 | do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; | |
577 | do_gtod.varp->tb_to_xs = tb_to_xs; | |
578 | do_gtod.tb_to_us = tb_to_us; | |
579 | systemcfg->tb_orig_stamp = tb_last_stamp; | |
580 | systemcfg->tb_update_count = 0; | |
581 | systemcfg->tb_ticks_per_sec = tb_ticks_per_sec; | |
582 | systemcfg->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC; | |
583 | systemcfg->tb_to_xs = tb_to_xs; | |
584 | ||
585 | time_freq = 0; | |
586 | ||
587 | xtime.tv_nsec = 0; | |
588 | last_rtc_update = xtime.tv_sec; | |
589 | set_normalized_timespec(&wall_to_monotonic, | |
590 | -xtime.tv_sec, -xtime.tv_nsec); | |
591 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
592 | ||
593 | /* Not exact, but the timer interrupt takes care of this */ | |
594 | set_dec(tb_ticks_per_jiffy); | |
595 | } | |
596 | ||
597 | /* | |
598 | * After adjtimex is called, adjust the conversion of tb ticks | |
599 | * to microseconds to keep do_gettimeofday synchronized | |
600 | * with ntpd. | |
601 | * | |
602 | * Use the time_adjust, time_freq and time_offset computed by adjtimex to | |
603 | * adjust the frequency. | |
604 | */ | |
605 | ||
606 | /* #define DEBUG_PPC_ADJTIMEX 1 */ | |
607 | ||
608 | void ppc_adjtimex(void) | |
609 | { | |
610 | unsigned long den, new_tb_ticks_per_sec, tb_ticks, old_xsec, new_tb_to_xs, new_xsec, new_stamp_xsec; | |
611 | unsigned long tb_ticks_per_sec_delta; | |
612 | long delta_freq, ltemp; | |
613 | struct div_result divres; | |
614 | unsigned long flags; | |
615 | struct gettimeofday_vars * temp_varp; | |
616 | unsigned temp_idx; | |
617 | long singleshot_ppm = 0; | |
618 | ||
619 | /* Compute parts per million frequency adjustment to accomplish the time adjustment | |
620 | implied by time_offset to be applied over the elapsed time indicated by time_constant. | |
621 | Use SHIFT_USEC to get it into the same units as time_freq. */ | |
622 | if ( time_offset < 0 ) { | |
623 | ltemp = -time_offset; | |
624 | ltemp <<= SHIFT_USEC - SHIFT_UPDATE; | |
625 | ltemp >>= SHIFT_KG + time_constant; | |
626 | ltemp = -ltemp; | |
627 | } | |
628 | else { | |
629 | ltemp = time_offset; | |
630 | ltemp <<= SHIFT_USEC - SHIFT_UPDATE; | |
631 | ltemp >>= SHIFT_KG + time_constant; | |
632 | } | |
633 | ||
634 | /* If there is a single shot time adjustment in progress */ | |
635 | if ( time_adjust ) { | |
636 | #ifdef DEBUG_PPC_ADJTIMEX | |
637 | printk("ppc_adjtimex: "); | |
638 | if ( adjusting_time == 0 ) | |
639 | printk("starting "); | |
640 | printk("single shot time_adjust = %ld\n", time_adjust); | |
641 | #endif | |
642 | ||
643 | adjusting_time = 1; | |
644 | ||
645 | /* Compute parts per million frequency adjustment to match time_adjust */ | |
646 | singleshot_ppm = tickadj * HZ; | |
647 | /* | |
648 | * The adjustment should be tickadj*HZ to match the code in | |
649 | * linux/kernel/timer.c, but experiments show that this is too | |
650 | * large. 3/4 of tickadj*HZ seems about right | |
651 | */ | |
652 | singleshot_ppm -= singleshot_ppm / 4; | |
653 | /* Use SHIFT_USEC to get it into the same units as time_freq */ | |
654 | singleshot_ppm <<= SHIFT_USEC; | |
655 | if ( time_adjust < 0 ) | |
656 | singleshot_ppm = -singleshot_ppm; | |
657 | } | |
658 | else { | |
659 | #ifdef DEBUG_PPC_ADJTIMEX | |
660 | if ( adjusting_time ) | |
661 | printk("ppc_adjtimex: ending single shot time_adjust\n"); | |
662 | #endif | |
663 | adjusting_time = 0; | |
664 | } | |
665 | ||
666 | /* Add up all of the frequency adjustments */ | |
667 | delta_freq = time_freq + ltemp + singleshot_ppm; | |
668 | ||
669 | /* Compute a new value for tb_ticks_per_sec based on the frequency adjustment */ | |
670 | den = 1000000 * (1 << (SHIFT_USEC - 8)); | |
671 | if ( delta_freq < 0 ) { | |
672 | tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( (-delta_freq) >> (SHIFT_USEC - 8))) / den; | |
673 | new_tb_ticks_per_sec = tb_ticks_per_sec + tb_ticks_per_sec_delta; | |
674 | } | |
675 | else { | |
676 | tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( delta_freq >> (SHIFT_USEC - 8))) / den; | |
677 | new_tb_ticks_per_sec = tb_ticks_per_sec - tb_ticks_per_sec_delta; | |
678 | } | |
679 | ||
680 | #ifdef DEBUG_PPC_ADJTIMEX | |
681 | printk("ppc_adjtimex: ltemp = %ld, time_freq = %ld, singleshot_ppm = %ld\n", ltemp, time_freq, singleshot_ppm); | |
682 | printk("ppc_adjtimex: tb_ticks_per_sec - base = %ld new = %ld\n", tb_ticks_per_sec, new_tb_ticks_per_sec); | |
683 | #endif | |
684 | ||
685 | /* Compute a new value of tb_to_xs (used to convert tb to microseconds and a new value of | |
686 | stamp_xsec which is the time (in 1/2^20 second units) corresponding to tb_orig_stamp. This | |
687 | new value of stamp_xsec compensates for the change in frequency (implied by the new tb_to_xs) | |
688 | which guarantees that the current time remains the same */ | |
689 | write_seqlock_irqsave( &xtime_lock, flags ); | |
690 | tb_ticks = get_tb() - do_gtod.varp->tb_orig_stamp; | |
691 | div128_by_32( 1024*1024, 0, new_tb_ticks_per_sec, &divres ); | |
692 | new_tb_to_xs = divres.result_low; | |
693 | new_xsec = mulhdu( tb_ticks, new_tb_to_xs ); | |
694 | ||
695 | old_xsec = mulhdu( tb_ticks, do_gtod.varp->tb_to_xs ); | |
696 | new_stamp_xsec = do_gtod.varp->stamp_xsec + old_xsec - new_xsec; | |
697 | ||
698 | /* There are two copies of tb_to_xs and stamp_xsec so that no lock is needed to access and use these | |
699 | values in do_gettimeofday. We alternate the copies and as long as a reasonable time elapses between | |
700 | changes, there will never be inconsistent values. ntpd has a minimum of one minute between updates */ | |
701 | ||
702 | temp_idx = (do_gtod.var_idx == 0); | |
703 | temp_varp = &do_gtod.vars[temp_idx]; | |
704 | ||
705 | temp_varp->tb_to_xs = new_tb_to_xs; | |
706 | temp_varp->stamp_xsec = new_stamp_xsec; | |
707 | temp_varp->tb_orig_stamp = do_gtod.varp->tb_orig_stamp; | |
0d8d4d42 | 708 | smp_mb(); |
1da177e4 LT |
709 | do_gtod.varp = temp_varp; |
710 | do_gtod.var_idx = temp_idx; | |
711 | ||
712 | /* | |
713 | * tb_update_count is used to allow the problem state gettimeofday code | |
714 | * to assure itself that it sees a consistent view of the tb_to_xs and | |
715 | * stamp_xsec variables. It reads the tb_update_count, then reads | |
716 | * tb_to_xs and stamp_xsec and then reads tb_update_count again. If | |
717 | * the two values of tb_update_count match and are even then the | |
718 | * tb_to_xs and stamp_xsec values are consistent. If not, then it | |
719 | * loops back and reads them again until this criteria is met. | |
720 | */ | |
721 | ++(systemcfg->tb_update_count); | |
0d8d4d42 | 722 | smp_wmb(); |
1da177e4 LT |
723 | systemcfg->tb_to_xs = new_tb_to_xs; |
724 | systemcfg->stamp_xsec = new_stamp_xsec; | |
0d8d4d42 | 725 | smp_wmb(); |
1da177e4 LT |
726 | ++(systemcfg->tb_update_count); |
727 | ||
728 | write_sequnlock_irqrestore( &xtime_lock, flags ); | |
729 | ||
730 | } | |
731 | ||
732 | ||
733 | #define TICK_SIZE tick | |
734 | #define FEBRUARY 2 | |
735 | #define STARTOFTIME 1970 | |
736 | #define SECDAY 86400L | |
737 | #define SECYR (SECDAY * 365) | |
738 | #define leapyear(year) ((year) % 4 == 0) | |
739 | #define days_in_year(a) (leapyear(a) ? 366 : 365) | |
740 | #define days_in_month(a) (month_days[(a) - 1]) | |
741 | ||
742 | static int month_days[12] = { | |
743 | 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 | |
744 | }; | |
745 | ||
746 | /* | |
747 | * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) | |
748 | */ | |
749 | void GregorianDay(struct rtc_time * tm) | |
750 | { | |
751 | int leapsToDate; | |
752 | int lastYear; | |
753 | int day; | |
754 | int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; | |
755 | ||
756 | lastYear=tm->tm_year-1; | |
757 | ||
758 | /* | |
759 | * Number of leap corrections to apply up to end of last year | |
760 | */ | |
761 | leapsToDate = lastYear/4 - lastYear/100 + lastYear/400; | |
762 | ||
763 | /* | |
764 | * This year is a leap year if it is divisible by 4 except when it is | |
765 | * divisible by 100 unless it is divisible by 400 | |
766 | * | |
767 | * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 will be | |
768 | */ | |
769 | if((tm->tm_year%4==0) && | |
770 | ((tm->tm_year%100!=0) || (tm->tm_year%400==0)) && | |
771 | (tm->tm_mon>2)) | |
772 | { | |
773 | /* | |
774 | * We are past Feb. 29 in a leap year | |
775 | */ | |
776 | day=1; | |
777 | } | |
778 | else | |
779 | { | |
780 | day=0; | |
781 | } | |
782 | ||
783 | day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + | |
784 | tm->tm_mday; | |
785 | ||
786 | tm->tm_wday=day%7; | |
787 | } | |
788 | ||
789 | void to_tm(int tim, struct rtc_time * tm) | |
790 | { | |
791 | register int i; | |
792 | register long hms, day; | |
793 | ||
794 | day = tim / SECDAY; | |
795 | hms = tim % SECDAY; | |
796 | ||
797 | /* Hours, minutes, seconds are easy */ | |
798 | tm->tm_hour = hms / 3600; | |
799 | tm->tm_min = (hms % 3600) / 60; | |
800 | tm->tm_sec = (hms % 3600) % 60; | |
801 | ||
802 | /* Number of years in days */ | |
803 | for (i = STARTOFTIME; day >= days_in_year(i); i++) | |
804 | day -= days_in_year(i); | |
805 | tm->tm_year = i; | |
806 | ||
807 | /* Number of months in days left */ | |
808 | if (leapyear(tm->tm_year)) | |
809 | days_in_month(FEBRUARY) = 29; | |
810 | for (i = 1; day >= days_in_month(i); i++) | |
811 | day -= days_in_month(i); | |
812 | days_in_month(FEBRUARY) = 28; | |
813 | tm->tm_mon = i; | |
814 | ||
815 | /* Days are what is left over (+1) from all that. */ | |
816 | tm->tm_mday = day + 1; | |
817 | ||
818 | /* | |
819 | * Determine the day of week | |
820 | */ | |
821 | GregorianDay(tm); | |
822 | } | |
823 | ||
824 | /* Auxiliary function to compute scaling factors */ | |
825 | /* Actually the choice of a timebase running at 1/4 the of the bus | |
826 | * frequency giving resolution of a few tens of nanoseconds is quite nice. | |
827 | * It makes this computation very precise (27-28 bits typically) which | |
828 | * is optimistic considering the stability of most processor clock | |
829 | * oscillators and the precision with which the timebase frequency | |
830 | * is measured but does not harm. | |
831 | */ | |
832 | unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale) { | |
833 | unsigned mlt=0, tmp, err; | |
834 | /* No concern for performance, it's done once: use a stupid | |
835 | * but safe and compact method to find the multiplier. | |
836 | */ | |
837 | ||
838 | for (tmp = 1U<<31; tmp != 0; tmp >>= 1) { | |
839 | if (mulhwu(inscale, mlt|tmp) < outscale) mlt|=tmp; | |
840 | } | |
841 | ||
842 | /* We might still be off by 1 for the best approximation. | |
843 | * A side effect of this is that if outscale is too large | |
844 | * the returned value will be zero. | |
845 | * Many corner cases have been checked and seem to work, | |
846 | * some might have been forgotten in the test however. | |
847 | */ | |
848 | ||
849 | err = inscale*(mlt+1); | |
850 | if (err <= inscale/2) mlt++; | |
851 | return mlt; | |
852 | } | |
853 | ||
854 | /* | |
855 | * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit | |
856 | * result. | |
857 | */ | |
858 | ||
859 | void div128_by_32( unsigned long dividend_high, unsigned long dividend_low, | |
860 | unsigned divisor, struct div_result *dr ) | |
861 | { | |
862 | unsigned long a,b,c,d, w,x,y,z, ra,rb,rc; | |
863 | ||
864 | a = dividend_high >> 32; | |
865 | b = dividend_high & 0xffffffff; | |
866 | c = dividend_low >> 32; | |
867 | d = dividend_low & 0xffffffff; | |
868 | ||
869 | w = a/divisor; | |
870 | ra = (a - (w * divisor)) << 32; | |
871 | ||
872 | x = (ra + b)/divisor; | |
873 | rb = ((ra + b) - (x * divisor)) << 32; | |
874 | ||
875 | y = (rb + c)/divisor; | |
876 | rc = ((rb + b) - (y * divisor)) << 32; | |
877 | ||
878 | z = (rc + d)/divisor; | |
879 | ||
880 | dr->result_high = (w << 32) + x; | |
881 | dr->result_low = (y << 32) + z; | |
882 | ||
883 | } | |
884 |