blob: de8479769bb729cf3068e42d7b1488b462c0ff68 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * 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
35#include <linux/config.h>
36#include <linux/errno.h>
37#include <linux/module.h>
38#include <linux/sched.h>
39#include <linux/kernel.h>
40#include <linux/param.h>
41#include <linux/string.h>
42#include <linux/mm.h>
43#include <linux/interrupt.h>
44#include <linux/timex.h>
45#include <linux/kernel_stat.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070046#include <linux/time.h>
47#include <linux/init.h>
48#include <linux/profile.h>
49#include <linux/cpu.h>
50#include <linux/security.h>
Paul Mackerrasf2783c12005-10-20 09:23:26 +100051#include <linux/percpu.h>
52#include <linux/rtc.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
Linus Torvalds1da177e2005-04-16 15:20:36 -070054#include <asm/io.h>
55#include <asm/processor.h>
56#include <asm/nvram.h>
57#include <asm/cache.h>
58#include <asm/machdep.h>
Paul Mackerrasf2783c12005-10-20 09:23:26 +100059#include <asm/uaccess.h>
60#include <asm/time.h>
61#include <asm/prom.h>
62#include <asm/irq.h>
63#include <asm/div64.h>
Paul Mackerras2249ca92005-11-07 13:18:13 +110064#include <asm/smp.h>
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +110065#include <asm/vdso_datapage.h>
Paul Mackerrasf2783c12005-10-20 09:23:26 +100066#ifdef CONFIG_PPC64
Paul Mackerrasf2783c12005-10-20 09:23:26 +100067#include <asm/firmware.h>
68#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070069#ifdef CONFIG_PPC_ISERIES
Kelly Daly8875ccf2005-11-02 14:13:34 +110070#include <asm/iseries/it_lp_queue.h>
Kelly Daly8021b8a2005-11-02 11:41:12 +110071#include <asm/iseries/hv_call_xm.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070072#endif
Olof Johansson732ee212005-11-07 00:57:55 -080073#include <asm/smp.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070074
Linus Torvalds1da177e2005-04-16 15:20:36 -070075/* keep track of when we need to update the rtc */
76time_t last_rtc_update;
77extern int piranha_simulator;
78#ifdef CONFIG_PPC_ISERIES
79unsigned long iSeries_recal_titan = 0;
80unsigned long iSeries_recal_tb = 0;
81static unsigned long first_settimeofday = 1;
82#endif
83
Paul Mackerrasf2783c12005-10-20 09:23:26 +100084/* The decrementer counts down by 128 every 128ns on a 601. */
85#define DECREMENTER_COUNT_601 (1000000000 / HZ)
86
Linus Torvalds1da177e2005-04-16 15:20:36 -070087#define XSEC_PER_SEC (1024*1024)
88
Paul Mackerrasf2783c12005-10-20 09:23:26 +100089#ifdef CONFIG_PPC64
90#define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
91#else
92/* compute ((xsec << 12) * max) >> 32 */
93#define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
94#endif
95
Linus Torvalds1da177e2005-04-16 15:20:36 -070096unsigned long tb_ticks_per_jiffy;
97unsigned long tb_ticks_per_usec = 100; /* sane default */
98EXPORT_SYMBOL(tb_ticks_per_usec);
99unsigned long tb_ticks_per_sec;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000100u64 tb_to_xs;
101unsigned tb_to_us;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102unsigned long processor_freq;
103DEFINE_SPINLOCK(rtc_lock);
Benjamin Herrenschmidt6ae3db12005-06-27 14:36:35 -0700104EXPORT_SYMBOL_GPL(rtc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000106u64 tb_to_ns_scale;
107unsigned tb_to_ns_shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108
109struct gettimeofday_struct do_gtod;
110
111extern unsigned long wall_jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112
113extern struct timezone sys_tz;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000114static long timezone_offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115
116void ppc_adjtimex(void);
117
118static unsigned adjusting_time = 0;
119
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000120unsigned long ppc_proc_freq;
121unsigned long ppc_tb_freq;
122
Paul Mackerras96c44502005-10-23 17:14:56 +1000123u64 tb_last_jiffy __cacheline_aligned_in_smp;
124unsigned long tb_last_stamp;
125
126/*
127 * Note that on ppc32 this only stores the bottom 32 bits of
128 * the timebase value, but that's enough to tell when a jiffy
129 * has passed.
130 */
131DEFINE_PER_CPU(unsigned long, last_jiffy);
132
Paul Mackerras6defa382005-11-18 13:44:17 +1100133void __delay(unsigned long loops)
134{
135 unsigned long start;
136 int diff;
137
138 if (__USE_RTC()) {
139 start = get_rtcl();
140 do {
141 /* the RTCL register wraps at 1000000000 */
142 diff = get_rtcl() - start;
143 if (diff < 0)
144 diff += 1000000000;
145 } while (diff < loops);
146 } else {
147 start = get_tbl();
148 while (get_tbl() - start < loops)
149 HMT_low();
150 HMT_medium();
151 }
152}
153EXPORT_SYMBOL(__delay);
154
155void udelay(unsigned long usecs)
156{
157 __delay(tb_ticks_per_usec * usecs);
158}
159EXPORT_SYMBOL(udelay);
160
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161static __inline__ void timer_check_rtc(void)
162{
163 /*
164 * update the rtc when needed, this should be performed on the
165 * right fraction of a second. Half or full second ?
166 * Full second works on mk48t59 clocks, others need testing.
167 * Note that this update is basically only used through
168 * the adjtimex system calls. Setting the HW clock in
169 * any other way is a /dev/rtc and userland business.
170 * This is still wrong by -0.5/+1.5 jiffies because of the
171 * timer interrupt resolution and possible delay, but here we
172 * hit a quantization limit which can only be solved by higher
173 * resolution timers and decoupling time management from timer
174 * interrupts. This is also wrong on the clocks
175 * which require being written at the half second boundary.
176 * We should have an rtc call that only sets the minutes and
177 * seconds like on Intel to avoid problems with non UTC clocks.
178 */
Kumar Galad2e61512005-10-20 11:43:33 -0500179 if (ppc_md.set_rtc_time && ntp_synced() &&
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000180 xtime.tv_sec - last_rtc_update >= 659 &&
181 abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ &&
182 jiffies - wall_jiffies == 1) {
183 struct rtc_time tm;
184 to_tm(xtime.tv_sec + 1 + timezone_offset, &tm);
185 tm.tm_year -= 1900;
186 tm.tm_mon -= 1;
187 if (ppc_md.set_rtc_time(&tm) == 0)
188 last_rtc_update = xtime.tv_sec + 1;
189 else
190 /* Try again one minute later */
191 last_rtc_update += 60;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 }
193}
194
195/*
196 * This version of gettimeofday has microsecond resolution.
197 */
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000198static inline void __do_gettimeofday(struct timeval *tv, u64 tb_val)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199{
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000200 unsigned long sec, usec;
201 u64 tb_ticks, xsec;
202 struct gettimeofday_vars *temp_varp;
203 u64 temp_tb_to_xs, temp_stamp_xsec;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204
205 /*
206 * These calculations are faster (gets rid of divides)
207 * if done in units of 1/2^20 rather than microseconds.
208 * The conversion to microseconds at the end is done
209 * without a divide (and in fact, without a multiply)
210 */
211 temp_varp = do_gtod.varp;
212 tb_ticks = tb_val - temp_varp->tb_orig_stamp;
213 temp_tb_to_xs = temp_varp->tb_to_xs;
214 temp_stamp_xsec = temp_varp->stamp_xsec;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000215 xsec = temp_stamp_xsec + mulhdu(tb_ticks, temp_tb_to_xs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 sec = xsec / XSEC_PER_SEC;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000217 usec = (unsigned long)xsec & (XSEC_PER_SEC - 1);
218 usec = SCALE_XSEC(usec, 1000000);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219
220 tv->tv_sec = sec;
221 tv->tv_usec = usec;
222}
223
224void do_gettimeofday(struct timeval *tv)
225{
Paul Mackerras96c44502005-10-23 17:14:56 +1000226 if (__USE_RTC()) {
227 /* do this the old way */
228 unsigned long flags, seq;
229 unsigned int sec, nsec, usec, lost;
230
231 do {
232 seq = read_seqbegin_irqsave(&xtime_lock, flags);
233 sec = xtime.tv_sec;
234 nsec = xtime.tv_nsec + tb_ticks_since(tb_last_stamp);
235 lost = jiffies - wall_jiffies;
236 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
237 usec = nsec / 1000 + lost * (1000000 / HZ);
238 while (usec >= 1000000) {
239 usec -= 1000000;
240 ++sec;
241 }
242 tv->tv_sec = sec;
243 tv->tv_usec = usec;
244 return;
245 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 __do_gettimeofday(tv, get_tb());
247}
248
249EXPORT_SYMBOL(do_gettimeofday);
250
251/* Synchronize xtime with do_gettimeofday */
252
253static inline void timer_sync_xtime(unsigned long cur_tb)
254{
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000255#ifdef CONFIG_PPC64
256 /* why do we do this? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 struct timeval my_tv;
258
259 __do_gettimeofday(&my_tv, cur_tb);
260
261 if (xtime.tv_sec <= my_tv.tv_sec) {
262 xtime.tv_sec = my_tv.tv_sec;
263 xtime.tv_nsec = my_tv.tv_usec * 1000;
264 }
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000265#endif
266}
267
268/*
269 * There are two copies of tb_to_xs and stamp_xsec so that no
270 * lock is needed to access and use these values in
271 * do_gettimeofday. We alternate the copies and as long as a
272 * reasonable time elapses between changes, there will never
273 * be inconsistent values. ntpd has a minimum of one minute
274 * between updates.
275 */
276static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
Paul Mackerras5d14a182005-10-20 22:33:06 +1000277 u64 new_tb_to_xs)
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000278{
279 unsigned temp_idx;
280 struct gettimeofday_vars *temp_varp;
281
282 temp_idx = (do_gtod.var_idx == 0);
283 temp_varp = &do_gtod.vars[temp_idx];
284
285 temp_varp->tb_to_xs = new_tb_to_xs;
286 temp_varp->tb_orig_stamp = new_tb_stamp;
287 temp_varp->stamp_xsec = new_stamp_xsec;
288 smp_mb();
289 do_gtod.varp = temp_varp;
290 do_gtod.var_idx = temp_idx;
291
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000292 /*
293 * tb_update_count is used to allow the userspace gettimeofday code
294 * to assure itself that it sees a consistent view of the tb_to_xs and
295 * stamp_xsec variables. It reads the tb_update_count, then reads
296 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
297 * the two values of tb_update_count match and are even then the
298 * tb_to_xs and stamp_xsec values are consistent. If not, then it
299 * loops back and reads them again until this criteria is met.
300 */
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100301 ++(vdso_data->tb_update_count);
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000302 smp_wmb();
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100303 vdso_data->tb_orig_stamp = new_tb_stamp;
304 vdso_data->stamp_xsec = new_stamp_xsec;
305 vdso_data->tb_to_xs = new_tb_to_xs;
306 vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
307 vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000308 smp_wmb();
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100309 ++(vdso_data->tb_update_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310}
311
312/*
313 * When the timebase - tb_orig_stamp gets too big, we do a manipulation
314 * between tb_orig_stamp and stamp_xsec. The goal here is to keep the
315 * difference tb - tb_orig_stamp small enough to always fit inside a
316 * 32 bits number. This is a requirement of our fast 32 bits userland
317 * implementation in the vdso. If we "miss" a call to this function
318 * (interrupt latency, CPU locked in a spinlock, ...) and we end up
319 * with a too big difference, then the vdso will fallback to calling
320 * the syscall
321 */
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000322static __inline__ void timer_recalc_offset(u64 cur_tb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323{
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000324 unsigned long offset;
325 u64 new_stamp_xsec;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326
Paul Mackerras96c44502005-10-23 17:14:56 +1000327 if (__USE_RTC())
328 return;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000329 offset = cur_tb - do_gtod.varp->tb_orig_stamp;
330 if ((offset & 0x80000000u) == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 return;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000332 new_stamp_xsec = do_gtod.varp->stamp_xsec
333 + mulhdu(offset, do_gtod.varp->tb_to_xs);
334 update_gtod(cur_tb, new_stamp_xsec, do_gtod.varp->tb_to_xs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335}
336
337#ifdef CONFIG_SMP
338unsigned long profile_pc(struct pt_regs *regs)
339{
340 unsigned long pc = instruction_pointer(regs);
341
342 if (in_lock_functions(pc))
343 return regs->link;
344
345 return pc;
346}
347EXPORT_SYMBOL(profile_pc);
348#endif
349
350#ifdef CONFIG_PPC_ISERIES
351
352/*
353 * This function recalibrates the timebase based on the 49-bit time-of-day
354 * value in the Titan chip. The Titan is much more accurate than the value
355 * returned by the service processor for the timebase frequency.
356 */
357
358static void iSeries_tb_recal(void)
359{
360 struct div_result divres;
361 unsigned long titan, tb;
362 tb = get_tb();
363 titan = HvCallXm_loadTod();
364 if ( iSeries_recal_titan ) {
365 unsigned long tb_ticks = tb - iSeries_recal_tb;
366 unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12;
367 unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec;
368 unsigned long new_tb_ticks_per_jiffy = (new_tb_ticks_per_sec+(HZ/2))/HZ;
369 long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy;
370 char sign = '+';
371 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */
372 new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ;
373
374 if ( tick_diff < 0 ) {
375 tick_diff = -tick_diff;
376 sign = '-';
377 }
378 if ( tick_diff ) {
379 if ( tick_diff < tb_ticks_per_jiffy/25 ) {
380 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n",
381 new_tb_ticks_per_jiffy, sign, tick_diff );
382 tb_ticks_per_jiffy = new_tb_ticks_per_jiffy;
383 tb_ticks_per_sec = new_tb_ticks_per_sec;
384 div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres );
385 do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
386 tb_to_xs = divres.result_low;
387 do_gtod.varp->tb_to_xs = tb_to_xs;
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100388 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
389 vdso_data->tb_to_xs = tb_to_xs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 }
391 else {
392 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n"
393 " new tb_ticks_per_jiffy = %lu\n"
394 " old tb_ticks_per_jiffy = %lu\n",
395 new_tb_ticks_per_jiffy, tb_ticks_per_jiffy );
396 }
397 }
398 }
399 iSeries_recal_titan = titan;
400 iSeries_recal_tb = tb;
401}
402#endif
403
404/*
405 * For iSeries shared processors, we have to let the hypervisor
406 * set the hardware decrementer. We set a virtual decrementer
407 * in the lppaca and call the hypervisor if the virtual
408 * decrementer is less than the current value in the hardware
409 * decrementer. (almost always the new decrementer value will
410 * be greater than the current hardware decementer so the hypervisor
411 * call will not be needed)
412 */
413
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414/*
415 * timer_interrupt - gets called when the decrementer overflows,
416 * with interrupts disabled.
417 */
Kumar Galac7aeffc2005-09-19 09:30:27 -0500418void timer_interrupt(struct pt_regs * regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419{
420 int next_dec;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000421 int cpu = smp_processor_id();
422 unsigned long ticks;
423
424#ifdef CONFIG_PPC32
425 if (atomic_read(&ppc_n_lost_interrupts) != 0)
426 do_IRQ(regs);
427#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428
429 irq_enter();
430
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 profile_tick(CPU_PROFILING, regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000433#ifdef CONFIG_PPC_ISERIES
434 get_paca()->lppaca.int_dword.fields.decr_int = 0;
435#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000437 while ((ticks = tb_ticks_since(per_cpu(last_jiffy, cpu)))
438 >= tb_ticks_per_jiffy) {
439 /* Update last_jiffy */
440 per_cpu(last_jiffy, cpu) += tb_ticks_per_jiffy;
441 /* Handle RTCL overflow on 601 */
442 if (__USE_RTC() && per_cpu(last_jiffy, cpu) >= 1000000000)
443 per_cpu(last_jiffy, cpu) -= 1000000000;
444
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445 /*
446 * We cannot disable the decrementer, so in the period
447 * between this cpu's being marked offline in cpu_online_map
448 * and calling stop-self, it is taking timer interrupts.
449 * Avoid calling into the scheduler rebalancing code if this
450 * is the case.
451 */
452 if (!cpu_is_offline(cpu))
453 update_process_times(user_mode(regs));
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000454
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 /*
456 * No need to check whether cpu is offline here; boot_cpuid
457 * should have been fixed up by now.
458 */
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000459 if (cpu != boot_cpuid)
460 continue;
461
462 write_seqlock(&xtime_lock);
Paul Mackerras96c44502005-10-23 17:14:56 +1000463 tb_last_jiffy += tb_ticks_per_jiffy;
464 tb_last_stamp = per_cpu(last_jiffy, cpu);
465 timer_recalc_offset(tb_last_jiffy);
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000466 do_timer(regs);
Paul Mackerras96c44502005-10-23 17:14:56 +1000467 timer_sync_xtime(tb_last_jiffy);
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000468 timer_check_rtc();
469 write_sequnlock(&xtime_lock);
470 if (adjusting_time && (time_adjust == 0))
471 ppc_adjtimex();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 }
473
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000474 next_dec = tb_ticks_per_jiffy - ticks;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 set_dec(next_dec);
476
477#ifdef CONFIG_PPC_ISERIES
Michael Ellerman937b31b2005-06-30 15:15:42 +1000478 if (hvlpevent_is_pending())
Michael Ellerman74889802005-06-30 15:15:53 +1000479 process_hvlpevents(regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480#endif
481
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000482#ifdef CONFIG_PPC64
Stephen Rothwell8d15a3e2005-08-03 14:40:16 +1000483 /* collect purr register values often, for accurate calculations */
Stephen Rothwell1ababe12005-08-03 14:35:25 +1000484 if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
486 cu->current_tb = mfspr(SPRN_PURR);
487 }
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000488#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489
490 irq_exit();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491}
492
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000493void wakeup_decrementer(void)
494{
495 int i;
496
497 set_dec(tb_ticks_per_jiffy);
498 /*
499 * We don't expect this to be called on a machine with a 601,
500 * so using get_tbl is fine.
501 */
Paul Mackerras96c44502005-10-23 17:14:56 +1000502 tb_last_stamp = tb_last_jiffy = get_tb();
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000503 for_each_cpu(i)
504 per_cpu(last_jiffy, i) = tb_last_stamp;
505}
506
Paul Mackerrasa5b518e2005-10-22 14:55:23 +1000507#ifdef CONFIG_SMP
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000508void __init smp_space_timers(unsigned int max_cpus)
509{
510 int i;
511 unsigned long offset = tb_ticks_per_jiffy / max_cpus;
512 unsigned long previous_tb = per_cpu(last_jiffy, boot_cpuid);
513
Paul Mackerrascbe62e22005-11-10 14:28:03 +1100514 /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */
515 previous_tb -= tb_ticks_per_jiffy;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000516 for_each_cpu(i) {
517 if (i != boot_cpuid) {
518 previous_tb += offset;
519 per_cpu(last_jiffy, i) = previous_tb;
520 }
521 }
522}
523#endif
524
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525/*
526 * Scheduler clock - returns current time in nanosec units.
527 *
528 * Note: mulhdu(a, b) (multiply high double unsigned) returns
529 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
530 * are 64-bit unsigned numbers.
531 */
532unsigned long long sched_clock(void)
533{
Paul Mackerras96c44502005-10-23 17:14:56 +1000534 if (__USE_RTC())
535 return get_rtc();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 return mulhdu(get_tb(), tb_to_ns_scale) << tb_to_ns_shift;
537}
538
539int do_settimeofday(struct timespec *tv)
540{
541 time_t wtm_sec, new_sec = tv->tv_sec;
542 long wtm_nsec, new_nsec = tv->tv_nsec;
543 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 long int tb_delta;
Paul Mackerras5f6b5b92005-10-30 22:55:52 +1100545 u64 new_xsec, tb_delta_xs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546
547 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
548 return -EINVAL;
549
550 write_seqlock_irqsave(&xtime_lock, flags);
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000551
552 /*
553 * Updating the RTC is not the job of this code. If the time is
554 * stepped under NTP, the RTC will be updated after STA_UNSYNC
555 * is cleared. Tools like clock/hwclock either copy the RTC
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 * to the system time, in which case there is no point in writing
557 * to the RTC again, or write to the RTC but then they don't call
558 * settimeofday to perform this operation.
559 */
560#ifdef CONFIG_PPC_ISERIES
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000561 if (first_settimeofday) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 iSeries_tb_recal();
563 first_settimeofday = 0;
564 }
565#endif
566 tb_delta = tb_ticks_since(tb_last_stamp);
567 tb_delta += (jiffies - wall_jiffies) * tb_ticks_per_jiffy;
Paul Mackerras5f6b5b92005-10-30 22:55:52 +1100568 tb_delta_xs = mulhdu(tb_delta, do_gtod.varp->tb_to_xs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569
570 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - new_sec);
571 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - new_nsec);
572
573 set_normalized_timespec(&xtime, new_sec, new_nsec);
574 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
575
576 /* In case of a large backwards jump in time with NTP, we want the
577 * clock to be updated as soon as the PLL is again in lock.
578 */
579 last_rtc_update = new_sec - 658;
580
john stultzb149ee22005-09-06 15:17:46 -0700581 ntp_clear();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582
Paul Mackerras5f6b5b92005-10-30 22:55:52 +1100583 new_xsec = 0;
584 if (new_nsec != 0) {
585 new_xsec = (u64)new_nsec * XSEC_PER_SEC;
586 do_div(new_xsec, NSEC_PER_SEC);
587 }
588 new_xsec += (u64)new_sec * XSEC_PER_SEC - tb_delta_xs;
Paul Mackerras96c44502005-10-23 17:14:56 +1000589 update_gtod(tb_last_jiffy, new_xsec, do_gtod.varp->tb_to_xs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100591 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
592 vdso_data->tz_dsttime = sys_tz.tz_dsttime;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593
594 write_sequnlock_irqrestore(&xtime_lock, flags);
595 clock_was_set();
596 return 0;
597}
598
599EXPORT_SYMBOL(do_settimeofday);
600
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000601void __init generic_calibrate_decr(void)
602{
603 struct device_node *cpu;
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000604 unsigned int *fp;
605 int node_found;
606
607 /*
608 * The cpu node should have a timebase-frequency property
609 * to tell us the rate at which the decrementer counts.
610 */
611 cpu = of_find_node_by_type(NULL, "cpu");
612
613 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */
614 node_found = 0;
615 if (cpu != 0) {
616 fp = (unsigned int *)get_property(cpu, "timebase-frequency",
617 NULL);
618 if (fp != 0) {
619 node_found = 1;
620 ppc_tb_freq = *fp;
621 }
622 }
623 if (!node_found)
624 printk(KERN_ERR "WARNING: Estimating decrementer frequency "
625 "(not found)\n");
626
627 ppc_proc_freq = DEFAULT_PROC_FREQ;
628 node_found = 0;
629 if (cpu != 0) {
630 fp = (unsigned int *)get_property(cpu, "clock-frequency",
631 NULL);
632 if (fp != 0) {
633 node_found = 1;
634 ppc_proc_freq = *fp;
635 }
636 }
Kumar Gala0fd6f712005-10-25 23:02:59 -0500637#ifdef CONFIG_BOOKE
638 /* Set the time base to zero */
639 mtspr(SPRN_TBWL, 0);
640 mtspr(SPRN_TBWU, 0);
641
642 /* Clear any pending timer interrupts */
643 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS);
644
645 /* Enable decrementer interrupt */
646 mtspr(SPRN_TCR, TCR_DIE);
647#endif
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000648 if (!node_found)
649 printk(KERN_ERR "WARNING: Estimating processor frequency "
650 "(not found)\n");
651
652 of_node_put(cpu);
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000653}
Arnd Bergmann10f7e7c2005-06-23 09:43:07 +1000654
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000655unsigned long get_boot_time(void)
656{
657 struct rtc_time tm;
658
659 if (ppc_md.get_boot_time)
660 return ppc_md.get_boot_time();
661 if (!ppc_md.get_rtc_time)
662 return 0;
663 ppc_md.get_rtc_time(&tm);
664 return mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
665 tm.tm_hour, tm.tm_min, tm.tm_sec);
666}
667
668/* This function is only called on the boot processor */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669void __init time_init(void)
670{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671 unsigned long flags;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000672 unsigned long tm = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 struct div_result res;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000674 u64 scale;
675 unsigned shift;
676
677 if (ppc_md.time_init != NULL)
678 timezone_offset = ppc_md.time_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679
Paul Mackerras96c44502005-10-23 17:14:56 +1000680 if (__USE_RTC()) {
681 /* 601 processor: dec counts down by 128 every 128ns */
682 ppc_tb_freq = 1000000000;
683 tb_last_stamp = get_rtcl();
684 tb_last_jiffy = tb_last_stamp;
685 } else {
686 /* Normal PowerPC with timebase register */
687 ppc_md.calibrate_decr();
688 printk(KERN_INFO "time_init: decrementer frequency = %lu.%.6lu MHz\n",
689 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
690 printk(KERN_INFO "time_init: processor frequency = %lu.%.6lu MHz\n",
691 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
692 tb_last_stamp = tb_last_jiffy = get_tb();
693 }
Paul Mackerras374e99d2005-10-20 21:04:51 +1000694
695 tb_ticks_per_jiffy = ppc_tb_freq / HZ;
696 tb_ticks_per_sec = tb_ticks_per_jiffy * HZ;
697 tb_ticks_per_usec = ppc_tb_freq / 1000000;
698 tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000);
699 div128_by_32(1024*1024, 0, tb_ticks_per_sec, &res);
700 tb_to_xs = res.result_low;
701
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000702#ifdef CONFIG_PPC64
703 get_paca()->default_decr = tb_ticks_per_jiffy;
704#endif
705
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706 /*
707 * Compute scale factor for sched_clock.
708 * The calibrate_decr() function has set tb_ticks_per_sec,
709 * which is the timebase frequency.
710 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
711 * the 128-bit result as a 64.64 fixed-point number.
712 * We then shift that number right until it is less than 1.0,
713 * giving us the scale factor and shift count to use in
714 * sched_clock().
715 */
716 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res);
717 scale = res.result_low;
718 for (shift = 0; res.result_high != 0; ++shift) {
719 scale = (scale >> 1) | (res.result_high << 63);
720 res.result_high >>= 1;
721 }
722 tb_to_ns_scale = scale;
723 tb_to_ns_shift = shift;
724
725#ifdef CONFIG_PPC_ISERIES
726 if (!piranha_simulator)
727#endif
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000728 tm = get_boot_time();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729
730 write_seqlock_irqsave(&xtime_lock, flags);
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000731 xtime.tv_sec = tm;
732 xtime.tv_nsec = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733 do_gtod.varp = &do_gtod.vars[0];
734 do_gtod.var_idx = 0;
Paul Mackerras96c44502005-10-23 17:14:56 +1000735 do_gtod.varp->tb_orig_stamp = tb_last_jiffy;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000736 __get_cpu_var(last_jiffy) = tb_last_stamp;
737 do_gtod.varp->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
739 do_gtod.varp->tb_to_xs = tb_to_xs;
740 do_gtod.tb_to_us = tb_to_us;
Benjamin Herrenschmidta7f290d2005-11-11 21:15:21 +1100741
742 vdso_data->tb_orig_stamp = tb_last_jiffy;
743 vdso_data->tb_update_count = 0;
744 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
745 vdso_data->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC;
746 vdso_data->tb_to_xs = tb_to_xs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747
748 time_freq = 0;
749
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000750 /* If platform provided a timezone (pmac), we correct the time */
751 if (timezone_offset) {
752 sys_tz.tz_minuteswest = -timezone_offset / 60;
753 sys_tz.tz_dsttime = 0;
754 xtime.tv_sec -= timezone_offset;
755 }
756
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757 last_rtc_update = xtime.tv_sec;
758 set_normalized_timespec(&wall_to_monotonic,
759 -xtime.tv_sec, -xtime.tv_nsec);
760 write_sequnlock_irqrestore(&xtime_lock, flags);
761
762 /* Not exact, but the timer interrupt takes care of this */
763 set_dec(tb_ticks_per_jiffy);
764}
765
766/*
767 * After adjtimex is called, adjust the conversion of tb ticks
768 * to microseconds to keep do_gettimeofday synchronized
769 * with ntpd.
770 *
771 * Use the time_adjust, time_freq and time_offset computed by adjtimex to
772 * adjust the frequency.
773 */
774
775/* #define DEBUG_PPC_ADJTIMEX 1 */
776
777void ppc_adjtimex(void)
778{
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000779#ifdef CONFIG_PPC64
780 unsigned long den, new_tb_ticks_per_sec, tb_ticks, old_xsec,
781 new_tb_to_xs, new_xsec, new_stamp_xsec;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 unsigned long tb_ticks_per_sec_delta;
783 long delta_freq, ltemp;
784 struct div_result divres;
785 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786 long singleshot_ppm = 0;
787
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000788 /*
789 * Compute parts per million frequency adjustment to
790 * accomplish the time adjustment implied by time_offset to be
791 * applied over the elapsed time indicated by time_constant.
792 * Use SHIFT_USEC to get it into the same units as
793 * time_freq.
794 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 if ( time_offset < 0 ) {
796 ltemp = -time_offset;
797 ltemp <<= SHIFT_USEC - SHIFT_UPDATE;
798 ltemp >>= SHIFT_KG + time_constant;
799 ltemp = -ltemp;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000800 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 ltemp = time_offset;
802 ltemp <<= SHIFT_USEC - SHIFT_UPDATE;
803 ltemp >>= SHIFT_KG + time_constant;
804 }
805
806 /* If there is a single shot time adjustment in progress */
807 if ( time_adjust ) {
808#ifdef DEBUG_PPC_ADJTIMEX
809 printk("ppc_adjtimex: ");
810 if ( adjusting_time == 0 )
811 printk("starting ");
812 printk("single shot time_adjust = %ld\n", time_adjust);
813#endif
814
815 adjusting_time = 1;
816
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000817 /*
818 * Compute parts per million frequency adjustment
819 * to match time_adjust
820 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 singleshot_ppm = tickadj * HZ;
822 /*
823 * The adjustment should be tickadj*HZ to match the code in
824 * linux/kernel/timer.c, but experiments show that this is too
825 * large. 3/4 of tickadj*HZ seems about right
826 */
827 singleshot_ppm -= singleshot_ppm / 4;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000828 /* Use SHIFT_USEC to get it into the same units as time_freq */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 singleshot_ppm <<= SHIFT_USEC;
830 if ( time_adjust < 0 )
831 singleshot_ppm = -singleshot_ppm;
832 }
833 else {
834#ifdef DEBUG_PPC_ADJTIMEX
835 if ( adjusting_time )
836 printk("ppc_adjtimex: ending single shot time_adjust\n");
837#endif
838 adjusting_time = 0;
839 }
840
841 /* Add up all of the frequency adjustments */
842 delta_freq = time_freq + ltemp + singleshot_ppm;
843
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000844 /*
845 * Compute a new value for tb_ticks_per_sec based on
846 * the frequency adjustment
847 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848 den = 1000000 * (1 << (SHIFT_USEC - 8));
849 if ( delta_freq < 0 ) {
850 tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( (-delta_freq) >> (SHIFT_USEC - 8))) / den;
851 new_tb_ticks_per_sec = tb_ticks_per_sec + tb_ticks_per_sec_delta;
852 }
853 else {
854 tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( delta_freq >> (SHIFT_USEC - 8))) / den;
855 new_tb_ticks_per_sec = tb_ticks_per_sec - tb_ticks_per_sec_delta;
856 }
857
858#ifdef DEBUG_PPC_ADJTIMEX
859 printk("ppc_adjtimex: ltemp = %ld, time_freq = %ld, singleshot_ppm = %ld\n", ltemp, time_freq, singleshot_ppm);
860 printk("ppc_adjtimex: tb_ticks_per_sec - base = %ld new = %ld\n", tb_ticks_per_sec, new_tb_ticks_per_sec);
861#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862
863 /*
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000864 * Compute a new value of tb_to_xs (used to convert tb to
865 * microseconds) and a new value of stamp_xsec which is the
866 * time (in 1/2^20 second units) corresponding to
867 * tb_orig_stamp. This new value of stamp_xsec compensates
868 * for the change in frequency (implied by the new tb_to_xs)
869 * which guarantees that the current time remains the same.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 */
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000871 write_seqlock_irqsave( &xtime_lock, flags );
872 tb_ticks = get_tb() - do_gtod.varp->tb_orig_stamp;
873 div128_by_32(1024*1024, 0, new_tb_ticks_per_sec, &divres);
874 new_tb_to_xs = divres.result_low;
875 new_xsec = mulhdu(tb_ticks, new_tb_to_xs);
876
877 old_xsec = mulhdu(tb_ticks, do_gtod.varp->tb_to_xs);
878 new_stamp_xsec = do_gtod.varp->stamp_xsec + old_xsec - new_xsec;
879
880 update_gtod(do_gtod.varp->tb_orig_stamp, new_stamp_xsec, new_tb_to_xs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881
882 write_sequnlock_irqrestore( &xtime_lock, flags );
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000883#endif /* CONFIG_PPC64 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884}
885
886
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887#define FEBRUARY 2
888#define STARTOFTIME 1970
889#define SECDAY 86400L
890#define SECYR (SECDAY * 365)
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000891#define leapyear(year) ((year) % 4 == 0 && \
892 ((year) % 100 != 0 || (year) % 400 == 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893#define days_in_year(a) (leapyear(a) ? 366 : 365)
894#define days_in_month(a) (month_days[(a) - 1])
895
896static int month_days[12] = {
897 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
898};
899
900/*
901 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
902 */
903void GregorianDay(struct rtc_time * tm)
904{
905 int leapsToDate;
906 int lastYear;
907 int day;
908 int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
909
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000910 lastYear = tm->tm_year - 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911
912 /*
913 * Number of leap corrections to apply up to end of last year
914 */
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000915 leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916
917 /*
918 * This year is a leap year if it is divisible by 4 except when it is
919 * divisible by 100 unless it is divisible by 400
920 *
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000921 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922 */
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000923 day = tm->tm_mon > 2 && leapyear(tm->tm_year);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924
925 day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] +
926 tm->tm_mday;
927
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000928 tm->tm_wday = day % 7;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929}
930
931void to_tm(int tim, struct rtc_time * tm)
932{
933 register int i;
934 register long hms, day;
935
936 day = tim / SECDAY;
937 hms = tim % SECDAY;
938
939 /* Hours, minutes, seconds are easy */
940 tm->tm_hour = hms / 3600;
941 tm->tm_min = (hms % 3600) / 60;
942 tm->tm_sec = (hms % 3600) % 60;
943
944 /* Number of years in days */
945 for (i = STARTOFTIME; day >= days_in_year(i); i++)
946 day -= days_in_year(i);
947 tm->tm_year = i;
948
949 /* Number of months in days left */
950 if (leapyear(tm->tm_year))
951 days_in_month(FEBRUARY) = 29;
952 for (i = 1; day >= days_in_month(i); i++)
953 day -= days_in_month(i);
954 days_in_month(FEBRUARY) = 28;
955 tm->tm_mon = i;
956
957 /* Days are what is left over (+1) from all that. */
958 tm->tm_mday = day + 1;
959
960 /*
961 * Determine the day of week
962 */
963 GregorianDay(tm);
964}
965
966/* Auxiliary function to compute scaling factors */
967/* Actually the choice of a timebase running at 1/4 the of the bus
968 * frequency giving resolution of a few tens of nanoseconds is quite nice.
969 * It makes this computation very precise (27-28 bits typically) which
970 * is optimistic considering the stability of most processor clock
971 * oscillators and the precision with which the timebase frequency
972 * is measured but does not harm.
973 */
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000974unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale)
975{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 unsigned mlt=0, tmp, err;
977 /* No concern for performance, it's done once: use a stupid
978 * but safe and compact method to find the multiplier.
979 */
980
981 for (tmp = 1U<<31; tmp != 0; tmp >>= 1) {
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000982 if (mulhwu(inscale, mlt|tmp) < outscale)
983 mlt |= tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700984 }
985
986 /* We might still be off by 1 for the best approximation.
987 * A side effect of this is that if outscale is too large
988 * the returned value will be zero.
989 * Many corner cases have been checked and seem to work,
990 * some might have been forgotten in the test however.
991 */
992
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000993 err = inscale * (mlt+1);
994 if (err <= inscale/2)
995 mlt++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996 return mlt;
Paul Mackerrasf2783c12005-10-20 09:23:26 +1000997}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998
999/*
1000 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
1001 * result.
1002 */
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001003void div128_by_32(u64 dividend_high, u64 dividend_low,
1004 unsigned divisor, struct div_result *dr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005{
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001006 unsigned long a, b, c, d;
1007 unsigned long w, x, y, z;
1008 u64 ra, rb, rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009
1010 a = dividend_high >> 32;
1011 b = dividend_high & 0xffffffff;
1012 c = dividend_low >> 32;
1013 d = dividend_low & 0xffffffff;
1014
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001015 w = a / divisor;
1016 ra = ((u64)(a - (w * divisor)) << 32) + b;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001018 rb = ((u64) do_div(ra, divisor) << 32) + c;
1019 x = ra;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001021 rc = ((u64) do_div(rb, divisor) << 32) + d;
1022 y = rb;
1023
1024 do_div(rc, divisor);
1025 z = rc;
Paul Mackerrasf2783c12005-10-20 09:23:26 +10001026
1027 dr->result_high = ((u64)w << 32) + x;
1028 dr->result_low = ((u64)y << 32) + z;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001029
1030}