Commit | Line | Data |
---|---|---|
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 | ||
54 | #include <asm/segment.h> | |
55 | #include <asm/io.h> | |
56 | #include <asm/processor.h> | |
57 | #include <asm/nvram.h> | |
58 | #include <asm/cache.h> | |
59 | #include <asm/machdep.h> | |
60 | #ifdef CONFIG_PPC_ISERIES | |
61 | #include <asm/iSeries/ItLpQueue.h> | |
62 | #include <asm/iSeries/HvCallXm.h> | |
63 | #endif | |
64 | #include <asm/uaccess.h> | |
65 | #include <asm/time.h> | |
66 | #include <asm/ppcdebug.h> | |
67 | #include <asm/prom.h> | |
68 | #include <asm/sections.h> | |
69 | #include <asm/systemcfg.h> | |
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; | |
102 | extern unsigned long lpevent_count; | |
103 | extern int smp_tb_synchronized; | |
104 | ||
105 | extern struct timezone sys_tz; | |
106 | ||
107 | void ppc_adjtimex(void); | |
108 | ||
109 | static unsigned adjusting_time = 0; | |
110 | ||
10f7e7c1 AB |
111 | unsigned long ppc_proc_freq; |
112 | unsigned long ppc_tb_freq; | |
113 | ||
1da177e4 LT |
114 | static __inline__ void timer_check_rtc(void) |
115 | { | |
116 | /* | |
117 | * update the rtc when needed, this should be performed on the | |
118 | * right fraction of a second. Half or full second ? | |
119 | * Full second works on mk48t59 clocks, others need testing. | |
120 | * Note that this update is basically only used through | |
121 | * the adjtimex system calls. Setting the HW clock in | |
122 | * any other way is a /dev/rtc and userland business. | |
123 | * This is still wrong by -0.5/+1.5 jiffies because of the | |
124 | * timer interrupt resolution and possible delay, but here we | |
125 | * hit a quantization limit which can only be solved by higher | |
126 | * resolution timers and decoupling time management from timer | |
127 | * interrupts. This is also wrong on the clocks | |
128 | * which require being written at the half second boundary. | |
129 | * We should have an rtc call that only sets the minutes and | |
130 | * seconds like on Intel to avoid problems with non UTC clocks. | |
131 | */ | |
132 | if ( (time_status & STA_UNSYNC) == 0 && | |
133 | xtime.tv_sec - last_rtc_update >= 659 && | |
134 | abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ && | |
135 | jiffies - wall_jiffies == 1) { | |
136 | struct rtc_time tm; | |
137 | to_tm(xtime.tv_sec+1, &tm); | |
138 | tm.tm_year -= 1900; | |
139 | tm.tm_mon -= 1; | |
140 | if (ppc_md.set_rtc_time(&tm) == 0) | |
141 | last_rtc_update = xtime.tv_sec+1; | |
142 | else | |
143 | /* Try again one minute later */ | |
144 | last_rtc_update += 60; | |
145 | } | |
146 | } | |
147 | ||
148 | /* | |
149 | * This version of gettimeofday has microsecond resolution. | |
150 | */ | |
151 | static inline void __do_gettimeofday(struct timeval *tv, unsigned long tb_val) | |
152 | { | |
153 | unsigned long sec, usec, tb_ticks; | |
154 | unsigned long xsec, tb_xsec; | |
155 | struct gettimeofday_vars * temp_varp; | |
156 | unsigned long temp_tb_to_xs, temp_stamp_xsec; | |
157 | ||
158 | /* | |
159 | * These calculations are faster (gets rid of divides) | |
160 | * if done in units of 1/2^20 rather than microseconds. | |
161 | * The conversion to microseconds at the end is done | |
162 | * without a divide (and in fact, without a multiply) | |
163 | */ | |
164 | temp_varp = do_gtod.varp; | |
165 | tb_ticks = tb_val - temp_varp->tb_orig_stamp; | |
166 | temp_tb_to_xs = temp_varp->tb_to_xs; | |
167 | temp_stamp_xsec = temp_varp->stamp_xsec; | |
168 | tb_xsec = mulhdu( tb_ticks, temp_tb_to_xs ); | |
169 | xsec = temp_stamp_xsec + tb_xsec; | |
170 | sec = xsec / XSEC_PER_SEC; | |
171 | xsec -= sec * XSEC_PER_SEC; | |
172 | usec = (xsec * USEC_PER_SEC)/XSEC_PER_SEC; | |
173 | ||
174 | tv->tv_sec = sec; | |
175 | tv->tv_usec = usec; | |
176 | } | |
177 | ||
178 | void do_gettimeofday(struct timeval *tv) | |
179 | { | |
180 | __do_gettimeofday(tv, get_tb()); | |
181 | } | |
182 | ||
183 | EXPORT_SYMBOL(do_gettimeofday); | |
184 | ||
185 | /* Synchronize xtime with do_gettimeofday */ | |
186 | ||
187 | static inline void timer_sync_xtime(unsigned long cur_tb) | |
188 | { | |
189 | struct timeval my_tv; | |
190 | ||
191 | __do_gettimeofday(&my_tv, cur_tb); | |
192 | ||
193 | if (xtime.tv_sec <= my_tv.tv_sec) { | |
194 | xtime.tv_sec = my_tv.tv_sec; | |
195 | xtime.tv_nsec = my_tv.tv_usec * 1000; | |
196 | } | |
197 | } | |
198 | ||
199 | /* | |
200 | * When the timebase - tb_orig_stamp gets too big, we do a manipulation | |
201 | * between tb_orig_stamp and stamp_xsec. The goal here is to keep the | |
202 | * difference tb - tb_orig_stamp small enough to always fit inside a | |
203 | * 32 bits number. This is a requirement of our fast 32 bits userland | |
204 | * implementation in the vdso. If we "miss" a call to this function | |
205 | * (interrupt latency, CPU locked in a spinlock, ...) and we end up | |
206 | * with a too big difference, then the vdso will fallback to calling | |
207 | * the syscall | |
208 | */ | |
209 | static __inline__ void timer_recalc_offset(unsigned long cur_tb) | |
210 | { | |
211 | struct gettimeofday_vars * temp_varp; | |
212 | unsigned temp_idx; | |
213 | unsigned long offset, new_stamp_xsec, new_tb_orig_stamp; | |
214 | ||
215 | if (((cur_tb - do_gtod.varp->tb_orig_stamp) & 0x80000000u) == 0) | |
216 | return; | |
217 | ||
218 | temp_idx = (do_gtod.var_idx == 0); | |
219 | temp_varp = &do_gtod.vars[temp_idx]; | |
220 | ||
221 | new_tb_orig_stamp = cur_tb; | |
222 | offset = new_tb_orig_stamp - do_gtod.varp->tb_orig_stamp; | |
223 | new_stamp_xsec = do_gtod.varp->stamp_xsec + mulhdu(offset, do_gtod.varp->tb_to_xs); | |
224 | ||
225 | temp_varp->tb_to_xs = do_gtod.varp->tb_to_xs; | |
226 | temp_varp->tb_orig_stamp = new_tb_orig_stamp; | |
227 | temp_varp->stamp_xsec = new_stamp_xsec; | |
0d8d4d42 | 228 | smp_mb(); |
1da177e4 LT |
229 | do_gtod.varp = temp_varp; |
230 | do_gtod.var_idx = temp_idx; | |
231 | ||
232 | ++(systemcfg->tb_update_count); | |
0d8d4d42 | 233 | smp_wmb(); |
1da177e4 LT |
234 | systemcfg->tb_orig_stamp = new_tb_orig_stamp; |
235 | systemcfg->stamp_xsec = new_stamp_xsec; | |
0d8d4d42 | 236 | smp_wmb(); |
1da177e4 LT |
237 | ++(systemcfg->tb_update_count); |
238 | } | |
239 | ||
240 | #ifdef CONFIG_SMP | |
241 | unsigned long profile_pc(struct pt_regs *regs) | |
242 | { | |
243 | unsigned long pc = instruction_pointer(regs); | |
244 | ||
245 | if (in_lock_functions(pc)) | |
246 | return regs->link; | |
247 | ||
248 | return pc; | |
249 | } | |
250 | EXPORT_SYMBOL(profile_pc); | |
251 | #endif | |
252 | ||
253 | #ifdef CONFIG_PPC_ISERIES | |
254 | ||
255 | /* | |
256 | * This function recalibrates the timebase based on the 49-bit time-of-day | |
257 | * value in the Titan chip. The Titan is much more accurate than the value | |
258 | * returned by the service processor for the timebase frequency. | |
259 | */ | |
260 | ||
261 | static void iSeries_tb_recal(void) | |
262 | { | |
263 | struct div_result divres; | |
264 | unsigned long titan, tb; | |
265 | tb = get_tb(); | |
266 | titan = HvCallXm_loadTod(); | |
267 | if ( iSeries_recal_titan ) { | |
268 | unsigned long tb_ticks = tb - iSeries_recal_tb; | |
269 | unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12; | |
270 | unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec; | |
271 | unsigned long new_tb_ticks_per_jiffy = (new_tb_ticks_per_sec+(HZ/2))/HZ; | |
272 | long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy; | |
273 | char sign = '+'; | |
274 | /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */ | |
275 | new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ; | |
276 | ||
277 | if ( tick_diff < 0 ) { | |
278 | tick_diff = -tick_diff; | |
279 | sign = '-'; | |
280 | } | |
281 | if ( tick_diff ) { | |
282 | if ( tick_diff < tb_ticks_per_jiffy/25 ) { | |
283 | printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n", | |
284 | new_tb_ticks_per_jiffy, sign, tick_diff ); | |
285 | tb_ticks_per_jiffy = new_tb_ticks_per_jiffy; | |
286 | tb_ticks_per_sec = new_tb_ticks_per_sec; | |
287 | div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres ); | |
288 | do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; | |
289 | tb_to_xs = divres.result_low; | |
290 | do_gtod.varp->tb_to_xs = tb_to_xs; | |
291 | systemcfg->tb_ticks_per_sec = tb_ticks_per_sec; | |
292 | systemcfg->tb_to_xs = tb_to_xs; | |
293 | } | |
294 | else { | |
295 | printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" | |
296 | " new tb_ticks_per_jiffy = %lu\n" | |
297 | " old tb_ticks_per_jiffy = %lu\n", | |
298 | new_tb_ticks_per_jiffy, tb_ticks_per_jiffy ); | |
299 | } | |
300 | } | |
301 | } | |
302 | iSeries_recal_titan = titan; | |
303 | iSeries_recal_tb = tb; | |
304 | } | |
305 | #endif | |
306 | ||
307 | /* | |
308 | * For iSeries shared processors, we have to let the hypervisor | |
309 | * set the hardware decrementer. We set a virtual decrementer | |
310 | * in the lppaca and call the hypervisor if the virtual | |
311 | * decrementer is less than the current value in the hardware | |
312 | * decrementer. (almost always the new decrementer value will | |
313 | * be greater than the current hardware decementer so the hypervisor | |
314 | * call will not be needed) | |
315 | */ | |
316 | ||
317 | unsigned long tb_last_stamp __cacheline_aligned_in_smp; | |
318 | ||
319 | /* | |
320 | * timer_interrupt - gets called when the decrementer overflows, | |
321 | * with interrupts disabled. | |
322 | */ | |
323 | int timer_interrupt(struct pt_regs * regs) | |
324 | { | |
325 | int next_dec; | |
326 | unsigned long cur_tb; | |
327 | struct paca_struct *lpaca = get_paca(); | |
328 | unsigned long cpu = smp_processor_id(); | |
329 | ||
330 | irq_enter(); | |
331 | ||
1da177e4 | 332 | profile_tick(CPU_PROFILING, regs); |
1da177e4 LT |
333 | |
334 | lpaca->lppaca.int_dword.fields.decr_int = 0; | |
335 | ||
336 | while (lpaca->next_jiffy_update_tb <= (cur_tb = get_tb())) { | |
337 | /* | |
338 | * We cannot disable the decrementer, so in the period | |
339 | * between this cpu's being marked offline in cpu_online_map | |
340 | * and calling stop-self, it is taking timer interrupts. | |
341 | * Avoid calling into the scheduler rebalancing code if this | |
342 | * is the case. | |
343 | */ | |
344 | if (!cpu_is_offline(cpu)) | |
345 | update_process_times(user_mode(regs)); | |
346 | /* | |
347 | * No need to check whether cpu is offline here; boot_cpuid | |
348 | * should have been fixed up by now. | |
349 | */ | |
350 | if (cpu == boot_cpuid) { | |
351 | write_seqlock(&xtime_lock); | |
352 | tb_last_stamp = lpaca->next_jiffy_update_tb; | |
353 | timer_recalc_offset(lpaca->next_jiffy_update_tb); | |
354 | do_timer(regs); | |
355 | timer_sync_xtime(lpaca->next_jiffy_update_tb); | |
356 | timer_check_rtc(); | |
357 | write_sequnlock(&xtime_lock); | |
358 | if ( adjusting_time && (time_adjust == 0) ) | |
359 | ppc_adjtimex(); | |
360 | } | |
361 | lpaca->next_jiffy_update_tb += tb_ticks_per_jiffy; | |
362 | } | |
363 | ||
364 | next_dec = lpaca->next_jiffy_update_tb - cur_tb; | |
365 | if (next_dec > lpaca->default_decr) | |
366 | next_dec = lpaca->default_decr; | |
367 | set_dec(next_dec); | |
368 | ||
369 | #ifdef CONFIG_PPC_ISERIES | |
1b19bc72 ME |
370 | if (ItLpQueue_isLpIntPending()) |
371 | lpevent_count += ItLpQueue_process(regs); | |
1da177e4 LT |
372 | #endif |
373 | ||
374 | /* collect purr register values often, for accurate calculations */ | |
375 | #if defined(CONFIG_PPC_PSERIES) | |
376 | if (cur_cpu_spec->firmware_features & FW_FEATURE_SPLPAR) { | |
377 | struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); | |
378 | cu->current_tb = mfspr(SPRN_PURR); | |
379 | } | |
380 | #endif | |
381 | ||
382 | irq_exit(); | |
383 | ||
384 | return 1; | |
385 | } | |
386 | ||
387 | /* | |
388 | * Scheduler clock - returns current time in nanosec units. | |
389 | * | |
390 | * Note: mulhdu(a, b) (multiply high double unsigned) returns | |
391 | * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b | |
392 | * are 64-bit unsigned numbers. | |
393 | */ | |
394 | unsigned long long sched_clock(void) | |
395 | { | |
396 | return mulhdu(get_tb(), tb_to_ns_scale) << tb_to_ns_shift; | |
397 | } | |
398 | ||
399 | int do_settimeofday(struct timespec *tv) | |
400 | { | |
401 | time_t wtm_sec, new_sec = tv->tv_sec; | |
402 | long wtm_nsec, new_nsec = tv->tv_nsec; | |
403 | unsigned long flags; | |
404 | unsigned long delta_xsec; | |
405 | long int tb_delta; | |
406 | unsigned long new_xsec; | |
407 | ||
408 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
409 | return -EINVAL; | |
410 | ||
411 | write_seqlock_irqsave(&xtime_lock, flags); | |
412 | /* Updating the RTC is not the job of this code. If the time is | |
413 | * stepped under NTP, the RTC will be update after STA_UNSYNC | |
414 | * is cleared. Tool like clock/hwclock either copy the RTC | |
415 | * to the system time, in which case there is no point in writing | |
416 | * to the RTC again, or write to the RTC but then they don't call | |
417 | * settimeofday to perform this operation. | |
418 | */ | |
419 | #ifdef CONFIG_PPC_ISERIES | |
420 | if ( first_settimeofday ) { | |
421 | iSeries_tb_recal(); | |
422 | first_settimeofday = 0; | |
423 | } | |
424 | #endif | |
425 | tb_delta = tb_ticks_since(tb_last_stamp); | |
426 | tb_delta += (jiffies - wall_jiffies) * tb_ticks_per_jiffy; | |
427 | ||
428 | new_nsec -= tb_delta / tb_ticks_per_usec / 1000; | |
429 | ||
430 | wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - new_sec); | |
431 | wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - new_nsec); | |
432 | ||
433 | set_normalized_timespec(&xtime, new_sec, new_nsec); | |
434 | set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); | |
435 | ||
436 | /* In case of a large backwards jump in time with NTP, we want the | |
437 | * clock to be updated as soon as the PLL is again in lock. | |
438 | */ | |
439 | last_rtc_update = new_sec - 658; | |
440 | ||
441 | time_adjust = 0; /* stop active adjtime() */ | |
442 | time_status |= STA_UNSYNC; | |
443 | time_maxerror = NTP_PHASE_LIMIT; | |
444 | time_esterror = NTP_PHASE_LIMIT; | |
445 | ||
446 | delta_xsec = mulhdu( (tb_last_stamp-do_gtod.varp->tb_orig_stamp), | |
447 | do_gtod.varp->tb_to_xs ); | |
448 | ||
449 | new_xsec = (new_nsec * XSEC_PER_SEC) / NSEC_PER_SEC; | |
450 | new_xsec += new_sec * XSEC_PER_SEC; | |
451 | if ( new_xsec > delta_xsec ) { | |
452 | do_gtod.varp->stamp_xsec = new_xsec - delta_xsec; | |
453 | systemcfg->stamp_xsec = new_xsec - delta_xsec; | |
454 | } | |
455 | else { | |
456 | /* This is only for the case where the user is setting the time | |
457 | * way back to a time such that the boot time would have been | |
458 | * before 1970 ... eg. we booted ten days ago, and we are setting | |
459 | * the time to Jan 5, 1970 */ | |
460 | do_gtod.varp->stamp_xsec = new_xsec; | |
461 | do_gtod.varp->tb_orig_stamp = tb_last_stamp; | |
462 | systemcfg->stamp_xsec = new_xsec; | |
463 | systemcfg->tb_orig_stamp = tb_last_stamp; | |
464 | } | |
465 | ||
466 | systemcfg->tz_minuteswest = sys_tz.tz_minuteswest; | |
467 | systemcfg->tz_dsttime = sys_tz.tz_dsttime; | |
468 | ||
469 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
470 | clock_was_set(); | |
471 | return 0; | |
472 | } | |
473 | ||
474 | EXPORT_SYMBOL(do_settimeofday); | |
475 | ||
10f7e7c1 AB |
476 | #if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_MAPLE) || defined(CONFIG_PPC_BPA) |
477 | void __init generic_calibrate_decr(void) | |
478 | { | |
479 | struct device_node *cpu; | |
480 | struct div_result divres; | |
481 | unsigned int *fp; | |
482 | int node_found; | |
483 | ||
484 | /* | |
485 | * The cpu node should have a timebase-frequency property | |
486 | * to tell us the rate at which the decrementer counts. | |
487 | */ | |
488 | cpu = of_find_node_by_type(NULL, "cpu"); | |
489 | ||
490 | ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ | |
491 | node_found = 0; | |
492 | if (cpu != 0) { | |
493 | fp = (unsigned int *)get_property(cpu, "timebase-frequency", | |
494 | NULL); | |
495 | if (fp != 0) { | |
496 | node_found = 1; | |
497 | ppc_tb_freq = *fp; | |
498 | } | |
499 | } | |
500 | if (!node_found) | |
501 | printk(KERN_ERR "WARNING: Estimating decrementer frequency " | |
502 | "(not found)\n"); | |
503 | ||
504 | ppc_proc_freq = DEFAULT_PROC_FREQ; | |
505 | node_found = 0; | |
506 | if (cpu != 0) { | |
507 | fp = (unsigned int *)get_property(cpu, "clock-frequency", | |
508 | NULL); | |
509 | if (fp != 0) { | |
510 | node_found = 1; | |
511 | ppc_proc_freq = *fp; | |
512 | } | |
513 | } | |
514 | if (!node_found) | |
515 | printk(KERN_ERR "WARNING: Estimating processor frequency " | |
516 | "(not found)\n"); | |
517 | ||
518 | of_node_put(cpu); | |
519 | ||
520 | printk(KERN_INFO "time_init: decrementer frequency = %lu.%.6lu MHz\n", | |
521 | ppc_tb_freq/1000000, ppc_tb_freq%1000000); | |
522 | printk(KERN_INFO "time_init: processor frequency = %lu.%.6lu MHz\n", | |
523 | ppc_proc_freq/1000000, ppc_proc_freq%1000000); | |
524 | ||
525 | tb_ticks_per_jiffy = ppc_tb_freq / HZ; | |
526 | tb_ticks_per_sec = tb_ticks_per_jiffy * HZ; | |
527 | tb_ticks_per_usec = ppc_tb_freq / 1000000; | |
528 | tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000); | |
529 | div128_by_32(1024*1024, 0, tb_ticks_per_sec, &divres); | |
530 | tb_to_xs = divres.result_low; | |
531 | ||
532 | setup_default_decr(); | |
533 | } | |
534 | #endif | |
535 | ||
1da177e4 LT |
536 | void __init time_init(void) |
537 | { | |
538 | /* This function is only called on the boot processor */ | |
539 | unsigned long flags; | |
540 | struct rtc_time tm; | |
541 | struct div_result res; | |
542 | unsigned long scale, shift; | |
543 | ||
544 | ppc_md.calibrate_decr(); | |
545 | ||
546 | /* | |
547 | * Compute scale factor for sched_clock. | |
548 | * The calibrate_decr() function has set tb_ticks_per_sec, | |
549 | * which is the timebase frequency. | |
550 | * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret | |
551 | * the 128-bit result as a 64.64 fixed-point number. | |
552 | * We then shift that number right until it is less than 1.0, | |
553 | * giving us the scale factor and shift count to use in | |
554 | * sched_clock(). | |
555 | */ | |
556 | div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); | |
557 | scale = res.result_low; | |
558 | for (shift = 0; res.result_high != 0; ++shift) { | |
559 | scale = (scale >> 1) | (res.result_high << 63); | |
560 | res.result_high >>= 1; | |
561 | } | |
562 | tb_to_ns_scale = scale; | |
563 | tb_to_ns_shift = shift; | |
564 | ||
565 | #ifdef CONFIG_PPC_ISERIES | |
566 | if (!piranha_simulator) | |
567 | #endif | |
568 | ppc_md.get_boot_time(&tm); | |
569 | ||
570 | write_seqlock_irqsave(&xtime_lock, flags); | |
571 | xtime.tv_sec = mktime(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, | |
572 | tm.tm_hour, tm.tm_min, tm.tm_sec); | |
573 | tb_last_stamp = get_tb(); | |
574 | do_gtod.varp = &do_gtod.vars[0]; | |
575 | do_gtod.var_idx = 0; | |
576 | do_gtod.varp->tb_orig_stamp = tb_last_stamp; | |
8f80e5c9 | 577 | get_paca()->next_jiffy_update_tb = tb_last_stamp + tb_ticks_per_jiffy; |
1da177e4 LT |
578 | do_gtod.varp->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC; |
579 | do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; | |
580 | do_gtod.varp->tb_to_xs = tb_to_xs; | |
581 | do_gtod.tb_to_us = tb_to_us; | |
582 | systemcfg->tb_orig_stamp = tb_last_stamp; | |
583 | systemcfg->tb_update_count = 0; | |
584 | systemcfg->tb_ticks_per_sec = tb_ticks_per_sec; | |
585 | systemcfg->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC; | |
586 | systemcfg->tb_to_xs = tb_to_xs; | |
587 | ||
588 | time_freq = 0; | |
589 | ||
590 | xtime.tv_nsec = 0; | |
591 | last_rtc_update = xtime.tv_sec; | |
592 | set_normalized_timespec(&wall_to_monotonic, | |
593 | -xtime.tv_sec, -xtime.tv_nsec); | |
594 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
595 | ||
596 | /* Not exact, but the timer interrupt takes care of this */ | |
597 | set_dec(tb_ticks_per_jiffy); | |
598 | } | |
599 | ||
600 | /* | |
601 | * After adjtimex is called, adjust the conversion of tb ticks | |
602 | * to microseconds to keep do_gettimeofday synchronized | |
603 | * with ntpd. | |
604 | * | |
605 | * Use the time_adjust, time_freq and time_offset computed by adjtimex to | |
606 | * adjust the frequency. | |
607 | */ | |
608 | ||
609 | /* #define DEBUG_PPC_ADJTIMEX 1 */ | |
610 | ||
611 | void ppc_adjtimex(void) | |
612 | { | |
613 | unsigned long den, new_tb_ticks_per_sec, tb_ticks, old_xsec, new_tb_to_xs, new_xsec, new_stamp_xsec; | |
614 | unsigned long tb_ticks_per_sec_delta; | |
615 | long delta_freq, ltemp; | |
616 | struct div_result divres; | |
617 | unsigned long flags; | |
618 | struct gettimeofday_vars * temp_varp; | |
619 | unsigned temp_idx; | |
620 | long singleshot_ppm = 0; | |
621 | ||
622 | /* Compute parts per million frequency adjustment to accomplish the time adjustment | |
623 | implied by time_offset to be applied over the elapsed time indicated by time_constant. | |
624 | Use SHIFT_USEC to get it into the same units as time_freq. */ | |
625 | if ( time_offset < 0 ) { | |
626 | ltemp = -time_offset; | |
627 | ltemp <<= SHIFT_USEC - SHIFT_UPDATE; | |
628 | ltemp >>= SHIFT_KG + time_constant; | |
629 | ltemp = -ltemp; | |
630 | } | |
631 | else { | |
632 | ltemp = time_offset; | |
633 | ltemp <<= SHIFT_USEC - SHIFT_UPDATE; | |
634 | ltemp >>= SHIFT_KG + time_constant; | |
635 | } | |
636 | ||
637 | /* If there is a single shot time adjustment in progress */ | |
638 | if ( time_adjust ) { | |
639 | #ifdef DEBUG_PPC_ADJTIMEX | |
640 | printk("ppc_adjtimex: "); | |
641 | if ( adjusting_time == 0 ) | |
642 | printk("starting "); | |
643 | printk("single shot time_adjust = %ld\n", time_adjust); | |
644 | #endif | |
645 | ||
646 | adjusting_time = 1; | |
647 | ||
648 | /* Compute parts per million frequency adjustment to match time_adjust */ | |
649 | singleshot_ppm = tickadj * HZ; | |
650 | /* | |
651 | * The adjustment should be tickadj*HZ to match the code in | |
652 | * linux/kernel/timer.c, but experiments show that this is too | |
653 | * large. 3/4 of tickadj*HZ seems about right | |
654 | */ | |
655 | singleshot_ppm -= singleshot_ppm / 4; | |
656 | /* Use SHIFT_USEC to get it into the same units as time_freq */ | |
657 | singleshot_ppm <<= SHIFT_USEC; | |
658 | if ( time_adjust < 0 ) | |
659 | singleshot_ppm = -singleshot_ppm; | |
660 | } | |
661 | else { | |
662 | #ifdef DEBUG_PPC_ADJTIMEX | |
663 | if ( adjusting_time ) | |
664 | printk("ppc_adjtimex: ending single shot time_adjust\n"); | |
665 | #endif | |
666 | adjusting_time = 0; | |
667 | } | |
668 | ||
669 | /* Add up all of the frequency adjustments */ | |
670 | delta_freq = time_freq + ltemp + singleshot_ppm; | |
671 | ||
672 | /* Compute a new value for tb_ticks_per_sec based on the frequency adjustment */ | |
673 | den = 1000000 * (1 << (SHIFT_USEC - 8)); | |
674 | if ( delta_freq < 0 ) { | |
675 | tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( (-delta_freq) >> (SHIFT_USEC - 8))) / den; | |
676 | new_tb_ticks_per_sec = tb_ticks_per_sec + tb_ticks_per_sec_delta; | |
677 | } | |
678 | else { | |
679 | tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( delta_freq >> (SHIFT_USEC - 8))) / den; | |
680 | new_tb_ticks_per_sec = tb_ticks_per_sec - tb_ticks_per_sec_delta; | |
681 | } | |
682 | ||
683 | #ifdef DEBUG_PPC_ADJTIMEX | |
684 | printk("ppc_adjtimex: ltemp = %ld, time_freq = %ld, singleshot_ppm = %ld\n", ltemp, time_freq, singleshot_ppm); | |
685 | printk("ppc_adjtimex: tb_ticks_per_sec - base = %ld new = %ld\n", tb_ticks_per_sec, new_tb_ticks_per_sec); | |
686 | #endif | |
687 | ||
688 | /* Compute a new value of tb_to_xs (used to convert tb to microseconds and a new value of | |
689 | stamp_xsec which is the time (in 1/2^20 second units) corresponding to tb_orig_stamp. This | |
690 | new value of stamp_xsec compensates for the change in frequency (implied by the new tb_to_xs) | |
691 | which guarantees that the current time remains the same */ | |
692 | write_seqlock_irqsave( &xtime_lock, flags ); | |
693 | tb_ticks = get_tb() - do_gtod.varp->tb_orig_stamp; | |
694 | div128_by_32( 1024*1024, 0, new_tb_ticks_per_sec, &divres ); | |
695 | new_tb_to_xs = divres.result_low; | |
696 | new_xsec = mulhdu( tb_ticks, new_tb_to_xs ); | |
697 | ||
698 | old_xsec = mulhdu( tb_ticks, do_gtod.varp->tb_to_xs ); | |
699 | new_stamp_xsec = do_gtod.varp->stamp_xsec + old_xsec - new_xsec; | |
700 | ||
701 | /* There are two copies of tb_to_xs and stamp_xsec so that no lock is needed to access and use these | |
702 | values in do_gettimeofday. We alternate the copies and as long as a reasonable time elapses between | |
703 | changes, there will never be inconsistent values. ntpd has a minimum of one minute between updates */ | |
704 | ||
705 | temp_idx = (do_gtod.var_idx == 0); | |
706 | temp_varp = &do_gtod.vars[temp_idx]; | |
707 | ||
708 | temp_varp->tb_to_xs = new_tb_to_xs; | |
709 | temp_varp->stamp_xsec = new_stamp_xsec; | |
710 | temp_varp->tb_orig_stamp = do_gtod.varp->tb_orig_stamp; | |
0d8d4d42 | 711 | smp_mb(); |
1da177e4 LT |
712 | do_gtod.varp = temp_varp; |
713 | do_gtod.var_idx = temp_idx; | |
714 | ||
715 | /* | |
716 | * tb_update_count is used to allow the problem state gettimeofday code | |
717 | * to assure itself that it sees a consistent view of the tb_to_xs and | |
718 | * stamp_xsec variables. It reads the tb_update_count, then reads | |
719 | * tb_to_xs and stamp_xsec and then reads tb_update_count again. If | |
720 | * the two values of tb_update_count match and are even then the | |
721 | * tb_to_xs and stamp_xsec values are consistent. If not, then it | |
722 | * loops back and reads them again until this criteria is met. | |
723 | */ | |
724 | ++(systemcfg->tb_update_count); | |
0d8d4d42 | 725 | smp_wmb(); |
1da177e4 LT |
726 | systemcfg->tb_to_xs = new_tb_to_xs; |
727 | systemcfg->stamp_xsec = new_stamp_xsec; | |
0d8d4d42 | 728 | smp_wmb(); |
1da177e4 LT |
729 | ++(systemcfg->tb_update_count); |
730 | ||
731 | write_sequnlock_irqrestore( &xtime_lock, flags ); | |
732 | ||
733 | } | |
734 | ||
735 | ||
736 | #define TICK_SIZE tick | |
737 | #define FEBRUARY 2 | |
738 | #define STARTOFTIME 1970 | |
739 | #define SECDAY 86400L | |
740 | #define SECYR (SECDAY * 365) | |
741 | #define leapyear(year) ((year) % 4 == 0) | |
742 | #define days_in_year(a) (leapyear(a) ? 366 : 365) | |
743 | #define days_in_month(a) (month_days[(a) - 1]) | |
744 | ||
745 | static int month_days[12] = { | |
746 | 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 | |
747 | }; | |
748 | ||
749 | /* | |
750 | * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) | |
751 | */ | |
752 | void GregorianDay(struct rtc_time * tm) | |
753 | { | |
754 | int leapsToDate; | |
755 | int lastYear; | |
756 | int day; | |
757 | int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; | |
758 | ||
759 | lastYear=tm->tm_year-1; | |
760 | ||
761 | /* | |
762 | * Number of leap corrections to apply up to end of last year | |
763 | */ | |
764 | leapsToDate = lastYear/4 - lastYear/100 + lastYear/400; | |
765 | ||
766 | /* | |
767 | * This year is a leap year if it is divisible by 4 except when it is | |
768 | * divisible by 100 unless it is divisible by 400 | |
769 | * | |
770 | * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 will be | |
771 | */ | |
772 | if((tm->tm_year%4==0) && | |
773 | ((tm->tm_year%100!=0) || (tm->tm_year%400==0)) && | |
774 | (tm->tm_mon>2)) | |
775 | { | |
776 | /* | |
777 | * We are past Feb. 29 in a leap year | |
778 | */ | |
779 | day=1; | |
780 | } | |
781 | else | |
782 | { | |
783 | day=0; | |
784 | } | |
785 | ||
786 | day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + | |
787 | tm->tm_mday; | |
788 | ||
789 | tm->tm_wday=day%7; | |
790 | } | |
791 | ||
792 | void to_tm(int tim, struct rtc_time * tm) | |
793 | { | |
794 | register int i; | |
795 | register long hms, day; | |
796 | ||
797 | day = tim / SECDAY; | |
798 | hms = tim % SECDAY; | |
799 | ||
800 | /* Hours, minutes, seconds are easy */ | |
801 | tm->tm_hour = hms / 3600; | |
802 | tm->tm_min = (hms % 3600) / 60; | |
803 | tm->tm_sec = (hms % 3600) % 60; | |
804 | ||
805 | /* Number of years in days */ | |
806 | for (i = STARTOFTIME; day >= days_in_year(i); i++) | |
807 | day -= days_in_year(i); | |
808 | tm->tm_year = i; | |
809 | ||
810 | /* Number of months in days left */ | |
811 | if (leapyear(tm->tm_year)) | |
812 | days_in_month(FEBRUARY) = 29; | |
813 | for (i = 1; day >= days_in_month(i); i++) | |
814 | day -= days_in_month(i); | |
815 | days_in_month(FEBRUARY) = 28; | |
816 | tm->tm_mon = i; | |
817 | ||
818 | /* Days are what is left over (+1) from all that. */ | |
819 | tm->tm_mday = day + 1; | |
820 | ||
821 | /* | |
822 | * Determine the day of week | |
823 | */ | |
824 | GregorianDay(tm); | |
825 | } | |
826 | ||
827 | /* Auxiliary function to compute scaling factors */ | |
828 | /* Actually the choice of a timebase running at 1/4 the of the bus | |
829 | * frequency giving resolution of a few tens of nanoseconds is quite nice. | |
830 | * It makes this computation very precise (27-28 bits typically) which | |
831 | * is optimistic considering the stability of most processor clock | |
832 | * oscillators and the precision with which the timebase frequency | |
833 | * is measured but does not harm. | |
834 | */ | |
835 | unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale) { | |
836 | unsigned mlt=0, tmp, err; | |
837 | /* No concern for performance, it's done once: use a stupid | |
838 | * but safe and compact method to find the multiplier. | |
839 | */ | |
840 | ||
841 | for (tmp = 1U<<31; tmp != 0; tmp >>= 1) { | |
842 | if (mulhwu(inscale, mlt|tmp) < outscale) mlt|=tmp; | |
843 | } | |
844 | ||
845 | /* We might still be off by 1 for the best approximation. | |
846 | * A side effect of this is that if outscale is too large | |
847 | * the returned value will be zero. | |
848 | * Many corner cases have been checked and seem to work, | |
849 | * some might have been forgotten in the test however. | |
850 | */ | |
851 | ||
852 | err = inscale*(mlt+1); | |
853 | if (err <= inscale/2) mlt++; | |
854 | return mlt; | |
855 | } | |
856 | ||
857 | /* | |
858 | * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit | |
859 | * result. | |
860 | */ | |
861 | ||
862 | void div128_by_32( unsigned long dividend_high, unsigned long dividend_low, | |
863 | unsigned divisor, struct div_result *dr ) | |
864 | { | |
865 | unsigned long a,b,c,d, w,x,y,z, ra,rb,rc; | |
866 | ||
867 | a = dividend_high >> 32; | |
868 | b = dividend_high & 0xffffffff; | |
869 | c = dividend_low >> 32; | |
870 | d = dividend_low & 0xffffffff; | |
871 | ||
872 | w = a/divisor; | |
873 | ra = (a - (w * divisor)) << 32; | |
874 | ||
875 | x = (ra + b)/divisor; | |
876 | rb = ((ra + b) - (x * divisor)) << 32; | |
877 | ||
878 | y = (rb + c)/divisor; | |
879 | rc = ((rb + b) - (y * divisor)) << 32; | |
880 | ||
881 | z = (rc + d)/divisor; | |
882 | ||
883 | dr->result_high = (w << 32) + x; | |
884 | dr->result_low = (y << 32) + z; | |
885 | ||
886 | } | |
887 |