aboutsummaryrefslogtreecommitdiffstats
path: root/arch/cris/arch-v10/kernel/fasttimer.c
blob: 094ff45ae85b58552ea1747f3828c0357df6268f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
/* $Id: fasttimer.c,v 1.9 2005/03/04 08:16:16 starvik Exp $
 * linux/arch/cris/kernel/fasttimer.c
 *
 * Fast timers for ETRAX100/ETRAX100LX
 * This may be useful in other OS than Linux so use 2 space indentation...
 *
 * $Log: fasttimer.c,v $
 * Revision 1.9  2005/03/04 08:16:16  starvik
 * Merge of Linux 2.6.11.
 *
 * Revision 1.8  2005/01/05 06:09:29  starvik
 * cli()/sti() will be obsolete in 2.6.11.
 *
 * Revision 1.7  2005/01/03 13:35:46  starvik
 * Removed obsolete stuff.
 * Mark fast timer IRQ as not shared.
 *
 * Revision 1.6  2004/05/14 10:18:39  starvik
 * Export fast_timer_list
 *
 * Revision 1.5  2004/05/14 07:58:01  starvik
 * Merge of changes from 2.4
 *
 * Revision 1.4  2003/07/04 08:27:41  starvik
 * Merge of Linux 2.5.74
 *
 * Revision 1.3  2002/12/12 08:26:32  starvik
 * Don't use C-comments inside CVS comments
 *
 * Revision 1.2  2002/12/11 15:42:02  starvik
 * Extracted v10 (ETRAX 100LX) specific stuff from arch/cris/kernel/
 *
 * Revision 1.1  2002/11/18 07:58:06  starvik
 * Fast timers (from Linux 2.4)
 *
 * Revision 1.5  2002/10/15 06:21:39  starvik
 * Added call to init_waitqueue_head
 *
 * Revision 1.4  2002/05/28 17:47:59  johana
 * Added del_fast_timer()
 *
 * Revision 1.3  2002/05/28 16:16:07  johana
 * Handle empty fast_timer_list
 *
 * Revision 1.2  2002/05/27 15:38:42  johana
 * Made it compile without warnings on Linux 2.4.
 * (includes, wait_queue, PROC_FS and snprintf)
 *
 * Revision 1.1  2002/05/27 15:32:25  johana
 * arch/etrax100/kernel/fasttimer.c v1.8 from the elinux tree.
 *
 * Revision 1.8  2001/11/27 13:50:40  pkj
 * Disable interrupts while stopping the timer and while modifying the
 * list of active timers in timer1_handler() as it may be interrupted
 * by other interrupts (e.g., the serial interrupt) which may add fast
 * timers.
 *
 * Revision 1.7  2001/11/22 11:50:32  pkj
 * * Only store information about the last 16 timers.
 * * proc_fasttimer_read() now uses an allocated buffer, since it
 *   requires more space than just a page even for only writing the
 *   last 16 timers. The buffer is only allocated on request, so
 *   unless /proc/fasttimer is read, it is never allocated.
 * * Renamed fast_timer_started to fast_timers_started to match
 *   fast_timers_added and fast_timers_expired.
 * * Some clean-up.
 *
 * Revision 1.6  2000/12/13 14:02:08  johana
 * Removed volatile for fast_timer_list
 *
 * Revision 1.5  2000/12/13 13:55:35  johana
 * Added DEBUG_LOG, added som cli() and cleanup
 *
 * Revision 1.4  2000/12/05 13:48:50  johana
 * Added range check when writing proc file, modified timer int handling
 *
 * Revision 1.3  2000/11/23 10:10:20  johana
 * More debug/logging possibilities.
 * Moved GET_JIFFIES_USEC() to timex.h and time.c
 *
 * Revision 1.2  2000/11/01 13:41:04  johana
 * Clean up and bugfixes.
 * Created new do_gettimeofday_fast() that gets a timeval struct
 * with time based on jiffies and *R_TIMER0_DATA, uses a table
 * for fast conversion of timer value to microseconds.
 * (Much faster the standard do_gettimeofday() and we don't really
 * wan't to use the true time - we wan't the "uptime" so timers don't screw up
 * when we change the time.
 * TODO: Add efficient support for continuous timers as well.
 *
 * Revision 1.1  2000/10/26 15:49:16  johana
 * Added fasttimer, highresolution timers.
 *
 * Copyright (C) 2000,2001 2002 Axis Communications AB, Lund, Sweden
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/delay.h>

#include <asm/segment.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/delay.h>
#include <asm/rtc.h>

#include <linux/config.h>
#include <linux/version.h>

#include <asm/arch/svinto.h>
#include <asm/fasttimer.h>
#include <linux/proc_fs.h>


#define DEBUG_LOG_INCLUDED
#define FAST_TIMER_LOG
//#define FAST_TIMER_TEST

#define FAST_TIMER_SANITY_CHECKS

#ifdef FAST_TIMER_SANITY_CHECKS
#define SANITYCHECK(x) x
static int sanity_failed = 0;
#else
#define SANITYCHECK(x)
#endif

#define D1(x)
#define D2(x)
#define DP(x)

#define __INLINE__ inline

static int fast_timer_running = 0;
static int fast_timers_added = 0;
static int fast_timers_started = 0;
static int fast_timers_expired = 0;
static int fast_timers_deleted = 0;
static int fast_timer_is_init = 0;
static int fast_timer_ints = 0;

struct fast_timer *fast_timer_list = NULL;

#ifdef DEBUG_LOG_INCLUDED
#define DEBUG_LOG_MAX 128
static const char * debug_log_string[DEBUG_LOG_MAX];
static unsigned long debug_log_value[DEBUG_LOG_MAX];
static int debug_log_cnt = 0;
static int debug_log_cnt_wrapped = 0;

#define DEBUG_LOG(string, value) \
{ \
  unsigned long log_flags; \
  local_irq_save(log_flags); \
  debug_log_string[debug_log_cnt] = (string); \
  debug_log_value[debug_log_cnt] = (unsigned long)(value); \
  if (++debug_log_cnt >= DEBUG_LOG_MAX) \
  { \
    debug_log_cnt = debug_log_cnt % DEBUG_LOG_MAX; \
    debug_log_cnt_wrapped = 1; \
  } \
  local_irq_restore(log_flags); \
}
#else
#define DEBUG_LOG(string, value)
#endif


/* The frequencies for index = clkselx number in R_TIMER_CTRL */
#define NUM_TIMER_FREQ 15
#define MAX_USABLE_TIMER_FREQ 7
#define MAX_DELAY_US  853333L
const unsigned long timer_freq_100[NUM_TIMER_FREQ] =
{
  3,   /* 0 3333 - 853333 us */
  6,   /* 1 1666 - 426666 us */
  12,  /* 2  833 - 213333 us */
  24,  /* 3  416 - 106666 us */
  48,  /* 4  208 -  53333 us */
  96,  /* 5  104 -  26666 us */
  192, /* 6   52 -  13333 us */
  384, /* 7   26 -   6666 us */
  576,
  1152,
  2304,
  4608,
  9216,
  18432,
  62500,
  /* 15 = cascade */
};
#define NUM_TIMER_STATS 16
#ifdef FAST_TIMER_LOG
struct fast_timer timer_added_log[NUM_TIMER_STATS];
struct fast_timer timer_started_log[NUM_TIMER_STATS];
struct fast_timer timer_expired_log[NUM_TIMER_STATS];
#endif

int timer_div_settings[NUM_TIMER_STATS];
int timer_freq_settings[NUM_TIMER_STATS];
int timer_delay_settings[NUM_TIMER_STATS];

/* Not true gettimeofday, only checks the jiffies (uptime) + useconds */
void __INLINE__ do_gettimeofday_fast(struct timeval *tv)
{
  unsigned long sec = jiffies;
  unsigned long usec = GET_JIFFIES_USEC();

  usec += (sec % HZ) * (1000000 / HZ);
  sec = sec / HZ;

  if (usec > 1000000)
  {
    usec -= 1000000;
    sec++;
  }
  tv->tv_sec = sec;
  tv->tv_usec = usec;
}

int __INLINE__ timeval_cmp(struct timeval *t0, struct timeval *t1)
{
  if (t0->tv_sec < t1->tv_sec)
  {
    return -1;
  }
  else if (t0->tv_sec > t1->tv_sec)
  {
    return 1;
  }
  if (t0->tv_usec < t1->tv_usec)
  {
    return -1;
  }
  else if (t0->tv_usec > t1->tv_usec)
  {
    return 1;
  }
  return 0;
}

void __INLINE__ start_timer1(unsigned long delay_us)
{
  int freq_index = 0; /* This is the lowest resolution */
  unsigned long upper_limit = MAX_DELAY_US;

  unsigned long div;
  /* Start/Restart the timer to the new shorter value */
  /* t = 1/freq = 1/19200 = 53us
   * T=div*t,  div = T/t = delay_us*freq/1000000
   */
#if 1 /* Adaptive timer settings */
  while (delay_us < upper_limit && freq_index < MAX_USABLE_TIMER_FREQ)
  {
    freq_index++;
    upper_limit >>= 1; /* Divide by 2 using shift */
  }
  if (freq_index > 0)
  {
    freq_index--;
  }
#else
  freq_index = 6;
#endif
  div = delay_us * timer_freq_100[freq_index]/10000;
  if (div < 2)
  {
    /* Maybe increase timer freq? */
    div = 2;
  }
  if (div > 255)
  {
    div = 0; /* This means 256, the max the timer takes */
    /* If a longer timeout than the timer can handle is used,
     * then we must restart it when it goes off.
     */
  }

  timer_div_settings[fast_timers_started % NUM_TIMER_STATS] = div;
  timer_freq_settings[fast_timers_started % NUM_TIMER_STATS] = freq_index;
  timer_delay_settings[fast_timers_started % NUM_TIMER_STATS] = delay_us;

  D1(printk("start_timer1 : %d us freq: %i div: %i\n",
            delay_us, freq_index, div));
  /* Clear timer1 irq */
  *R_IRQ_MASK0_CLR = IO_STATE(R_IRQ_MASK0_CLR, timer1, clr);

  /* Set timer values */
  *R_TIMER_CTRL = r_timer_ctrl_shadow =
    (r_timer_ctrl_shadow &
     ~IO_MASK(R_TIMER_CTRL, timerdiv1) &
     ~IO_MASK(R_TIMER_CTRL, tm1) &
     ~IO_MASK(R_TIMER_CTRL, clksel1)) |
    IO_FIELD(R_TIMER_CTRL, timerdiv1, div) |
    IO_STATE(R_TIMER_CTRL, tm1, stop_ld) |
    IO_FIELD(R_TIMER_CTRL, clksel1, freq_index ); /* 6=c19k2Hz */

  /* Ack interrupt */
  *R_TIMER_CTRL =  r_timer_ctrl_shadow |
    IO_STATE(R_TIMER_CTRL, i1, clr);

  /* Start timer */
  *R_TIMER_CTRL = r_timer_ctrl_shadow =
    (r_timer_ctrl_shadow & ~IO_MASK(R_TIMER_CTRL, tm1)) |
    IO_STATE(R_TIMER_CTRL, tm1, run);

  /* Enable timer1 irq */
  *R_IRQ_MASK0_SET = IO_STATE(R_IRQ_MASK0_SET, timer1, set);
  fast_timers_started++;
  fast_timer_running = 1;
}

/* In version 1.4 this function takes 27 - 50 us */
void start_one_shot_timer(struct fast_timer *t,
                          fast_timer_function_type *function,
                          unsigned long data,
                          unsigned long delay_us,
                          const char *name)
{
  unsigned long flags;
  struct fast_timer *tmp;

  D1(printk("sft %s %d us\n", name, delay_us));

  local_irq_save(flags);

  do_gettimeofday_fast(&t->tv_set);
  tmp = fast_timer_list;

  SANITYCHECK({ /* Check so this is not in the list already... */
    while (tmp != NULL)
    {
      if (tmp == t)
      {
        printk(KERN_WARNING
               "timer name: %s data: 0x%08lX already in list!\n", name, data);
        sanity_failed++;
        return;
      }
      else
      {
        tmp = tmp->next;
      }
    }
    tmp = fast_timer_list;
  });

  t->delay_us = delay_us;
  t->function = function;
  t->data = data;
  t->name = name;

  t->tv_expires.tv_usec = t->tv_set.tv_usec + delay_us % 1000000;
  t->tv_expires.tv_sec  = t->tv_set.tv_sec  + delay_us / 1000000;
  if (t->tv_expires.tv_usec > 1000000)
  {
    t->tv_expires.tv_usec -= 1000000;
    t->tv_expires.tv_sec++;
  }
#ifdef FAST_TIMER_LOG
  timer_added_log[fast_timers_added % NUM_TIMER_STATS] = *t;
#endif
  fast_timers_added++;

  /* Check if this should timeout before anything else */
  if (tmp == NULL || timeval_cmp(&t->tv_expires, &tmp->tv_expires) < 0)
  {
    /* Put first in list and modify the timer value */
    t->prev = NULL;
    t->next = fast_timer_list;
    if (fast_timer_list)
    {
      fast_timer_list->prev = t;
    }
    fast_timer_list = t;
#ifdef FAST_TIMER_LOG
    timer_started_log[fast_timers_started % NUM_TIMER_STATS] = *t;
#endif
    start_timer1(delay_us);
  } else {
    /* Put in correct place in list */
    while (tmp->next &&
           timeval_cmp(&t->tv_expires, &tmp->next->tv_expires) > 0)
    {
      tmp = tmp->next;
    }
    /* Insert t after tmp */
    t->prev = tmp;
    t->next = tmp->next;
    if (tmp->next)
    {
      tmp->next->prev = t;
    }
    tmp->next = t;
  }

  D2(printk("start_one_shot_timer: %d us done\n", delay_us));

  local_irq_restore(flags);
} /* start_one_shot_timer */

static inline int fast_timer_pending (const struct fast_timer * t)
{
  return (t->next != NULL) || (t->prev != NULL) || (t == fast_timer_list);
}

static inline int detach_fast_timer (struct fast_timer *t)
{
  struct fast_timer *next, *prev;
  if (!fast_timer_pending(t))
    return 0;
  next = t->next;
  prev = t->prev;
  if (next)
    next->prev = prev;
  if (prev)
    prev->next = next;
  else
    fast_timer_list = next;
  fast_timers_deleted++;
  return 1;
}

int del_fast_timer(struct fast_timer * t)
{
  unsigned long flags;
  int ret;
  
  local_irq_save(flags);
  ret = detach_fast_timer(t);
  t->next = t->prev = NULL;
  local_irq_restore(flags);
  return ret;
} /* del_fast_timer */


/* Interrupt routines or functions called in interrupt context */

/* Timer 1 interrupt handler */

static irqreturn_t
timer1_handler(int irq, void *dev_id, struct pt_regs *regs)
{
  struct fast_timer *t;
  unsigned long flags;

  local_irq_save(flags);

  /* Clear timer1 irq */
  *R_IRQ_MASK0_CLR = IO_STATE(R_IRQ_MASK0_CLR, timer1, clr);

  /* First stop timer, then ack interrupt */
  /* Stop timer */
  *R_TIMER_CTRL = r_timer_ctrl_shadow =
    (r_timer_ctrl_shadow & ~IO_MASK(R_TIMER_CTRL, tm1)) |
    IO_STATE(R_TIMER_CTRL, tm1, stop_ld);

  /* Ack interrupt */
  *R_TIMER_CTRL =  r_timer_ctrl_shadow | IO_STATE(R_TIMER_CTRL, i1, clr);

  fast_timer_running = 0;
  fast_timer_ints++;

  local_irq_restore(flags);

  t = fast_timer_list;
  while (t)
  {
    struct timeval tv;

    /* Has it really expired? */
    do_gettimeofday_fast(&tv);
    D1(printk("t: %is %06ius\n", tv.tv_sec, tv.tv_usec));

    if (timeval_cmp(&t->tv_expires, &tv) <= 0)
    {
      /* Yes it has expired */
#ifdef FAST_TIMER_LOG
      timer_expired_log[fast_timers_expired % NUM_TIMER_STATS] = *t;
#endif
      fast_timers_expired++;

      /* Remove this timer before call, since it may reuse the timer */
      local_irq_save(flags);
      if (t->prev)
      {
        t->prev->next = t->next;
      }
      else
      {
        fast_timer_list = t->next;
      }
      if (t->next)
      {
        t->next->prev = t->prev;
      }
      t->prev = NULL;
      t->next = NULL;
      local_irq_restore(flags);

      if (t->function != NULL)
      {
        t->function(t->data);
      }
      else
      {
        DEBUG_LOG("!timer1 %i function==NULL!\n", fast_timer_ints);
      }
    }
    else
    {
      /* Timer is to early, let's set it again using the normal routines */
      D1(printk(".\n"));
    }

    local_irq_save(flags);
    if ((t = fast_timer_list) != NULL)
    {
      /* Start next timer.. */
      long us;
      struct timeval tv;

      do_gettimeofday_fast(&tv);
      us = ((t->tv_expires.tv_sec - tv.tv_sec) * 1000000 +
            t->tv_expires.tv_usec - tv.tv_usec);
      if (us > 0)
      {
        if (!fast_timer_running)
        {
#ifdef FAST_TIMER_LOG
          timer_started_log[fast_timers_started % NUM_TIMER_STATS] = *t;
#endif
          start_timer1(us);
        }
        local_irq_restore(flags);
        break;
      }
      else
      {
        /* Timer already expired, let's handle it better late than never.
         * The normal loop handles it
         */
        D1(printk("e! %d\n", us));
      }
    }
    local_irq_restore(flags);
  }

  if (!t)
  {
    D1(printk("t1 stop!\n"));
  }

  return IRQ_HANDLED;
}

static void wake_up_func(unsigned long data)
{
#ifdef DECLARE_WAITQUEUE
  wait_queue_head_t  *sleep_wait_p = (wait_queue_head_t*)data;
#else
  struct wait_queue **sleep_wait_p = (struct wait_queue **)data;
#endif
  wake_up(sleep_wait_p);
}


/* Useful API */

void schedule_usleep(unsigned long us)
{
  struct fast_timer t;
#ifdef DECLARE_WAITQUEUE
  wait_queue_head_t sleep_wait;
  init_waitqueue_head(&sleep_wait);
  {
  DECLARE_WAITQUEUE(wait, current);
#else
  struct wait_queue *sleep_wait = NULL;
  struct wait_queue wait = { current, NULL };
#endif

  D1(printk("schedule_usleep(%d)\n", us));
  add_wait_queue(&sleep_wait, &wait);
  set_current_state(TASK_INTERRUPTIBLE);
  start_one_shot_timer(&t, wake_up_func, (unsigned long)&sleep_wait, us,
                       "usleep");
  schedule();
  set_current_state(TASK_RUNNING);
  remove_wait_queue(&sleep_wait, &wait);
  D1(printk("done schedule_usleep(%d)\n", us));
#ifdef DECLARE_WAITQUEUE
  }
#endif  
}

#ifdef CONFIG_PROC_FS
static int proc_fasttimer_read(char *buf, char **start, off_t offset, int len
                       ,int *eof, void *data_unused);
static struct proc_dir_entry *fasttimer_proc_entry;
#endif /* CONFIG_PROC_FS */

#ifdef CONFIG_PROC_FS

/* This value is very much based on testing */
#define BIG_BUF_SIZE (500 + NUM_TIMER_STATS * 300)

static int proc_fasttimer_read(char *buf, char **start, off_t offset, int len
                       ,int *eof, void *data_unused)
{
  unsigned long flags;
  int i = 0;
  int num_to_show;
  struct timeval tv;
  struct fast_timer *t, *nextt;
  static char *bigbuf = NULL;
  static unsigned long used;

  if (!bigbuf && !(bigbuf = vmalloc(BIG_BUF_SIZE)))
  {
    used = 0;
    bigbuf[0] = '\0';
    return 0;
  }

  if (!offset || !used)
  {
    do_gettimeofday_fast(&tv);

    used = 0;
    used += sprintf(bigbuf + used, "Fast timers added:     %i\n",
                    fast_timers_added);
    used += sprintf(bigbuf + used, "Fast timers started:   %i\n",
                    fast_timers_started);
    used += sprintf(bigbuf + used, "Fast timer interrupts: %i\n",
                    fast_timer_ints);
    used += sprintf(bigbuf + used, "Fast timers expired:   %i\n",
                    fast_timers_expired);
    used += sprintf(bigbuf + used, "Fast timers deleted:   %i\n",
                    fast_timers_deleted);
    used += sprintf(bigbuf + used, "Fast timer running:    %s\n",
                    fast_timer_running ? "yes" : "no");
    used += sprintf(bigbuf + used, "Current time:          %lu.%06lu\n",
                    (unsigned long)tv.tv_sec,
                    (unsigned long)tv.tv_usec);
#ifdef FAST_TIMER_SANITY_CHECKS
    used += sprintf(bigbuf + used, "Sanity failed:         %i\n",
                    sanity_failed);
#endif
    used += sprintf(bigbuf + used, "\n");

#ifdef DEBUG_LOG_INCLUDED
    {
      int end_i = debug_log_cnt;
      i = 0;

      if (debug_log_cnt_wrapped)
      {
        i = debug_log_cnt;
      }

      while ((i != end_i || (debug_log_cnt_wrapped && !used)) &&
             used+100 < BIG_BUF_SIZE)
      {
        used += sprintf(bigbuf + used, debug_log_string[i],
                        debug_log_value[i]);
        i = (i+1) % DEBUG_LOG_MAX;
      }
    }
    used += sprintf(bigbuf + used, "\n");
#endif

    num_to_show = (fast_timers_started < NUM_TIMER_STATS ? fast_timers_started:
                   NUM_TIMER_STATS);
    used += sprintf(bigbuf + used, "Timers started: %i\n", fast_timers_started);
    for (i = 0; i < num_to_show && (used+100 < BIG_BUF_SIZE) ; i++)
    {
      int cur = (fast_timers_started - i - 1) % NUM_TIMER_STATS;

#if 1 //ndef FAST_TIMER_LOG
      used += sprintf(bigbuf + used, "div: %i freq: %i delay: %i"
                      "\n",
                      timer_div_settings[cur],
                      timer_freq_settings[cur],
                      timer_delay_settings[cur]
                      );
#endif
#ifdef FAST_TIMER_LOG
      t = &timer_started_log[cur];
      used += sprintf(bigbuf + used, "%-14s s: %6lu.%06lu e: %6lu.%06lu "
                      "d: %6li us data: 0x%08lX"
                      "\n",
                      t->name,
                      (unsigned long)t->tv_set.tv_sec,
                      (unsigned long)t->tv_set.tv_usec,
                      (unsigned long)t->tv_expires.tv_sec,
                      (unsigned long)t->tv_expires.tv_usec,
                      t->delay_us,
                      t->data
                      );
#endif
    }
    used += sprintf(bigbuf + used, "\n");

#ifdef FAST_TIMER_LOG
    num_to_show = (fast_timers_added < NUM_TIMER_STATS ? fast_timers_added:
                   NUM_TIMER_STATS);
    used += sprintf(bigbuf + used, "Timers added: %i\n", fast_timers_added);
    for (i = 0; i < num_to_show && (used+100 < BIG_BUF_SIZE); i++)
    {
      t = &timer_added_log[(fast_timers_added - i - 1) % NUM_TIMER_STATS];
      used += sprintf(bigbuf + used, "%-14s s: %6lu.%06lu e: %6lu.%06lu "
                      "d: %6li us data: 0x%08lX"
                      "\n",
                      t->name,
                      (unsigned long)t->tv_set.tv_sec,
                      (unsigned long)t->tv_set.tv_usec,
                      (unsigned long)t->tv_expires.tv_sec,
                      (unsigned long)t->tv_expires.tv_usec,
                      t->delay_us,
                      t->data
                      );
    }
    used += sprintf(bigbuf + used, "\n");

    num_to_show = (fast_timers_expired < NUM_TIMER_STATS ? fast_timers_expired:
                   NUM_TIMER_STATS);
    used += sprintf(bigbuf + used, "Timers expired: %i\n", fast_timers_expired);
    for (i = 0; i < num_to_show && (used+100 < BIG_BUF_SIZE); i++)
    {
      t = &timer_expired_log[(fast_timers_expired - i - 1) % NUM_TIMER_STATS];
      used += sprintf(bigbuf + used, "%-14s s: %6lu.%06lu e: %6lu.%06lu "
                      "d: %6li us data: 0x%08lX"
                      "\n",
                      t->name,
                      (unsigned long)t->tv_set.tv_sec,
                      (unsigned long)t->tv_set.tv_usec,
                      (unsigned long)t->tv_expires.tv_sec,
                      (unsigned long)t->tv_expires.tv_usec,
                      t->delay_us,
                      t->data
                      );
    }
    used += sprintf(bigbuf + used, "\n");
#endif

    used += sprintf(bigbuf + used, "Active timers:\n");
    local_irq_save(flags);
    t = fast_timer_list;
    while (t != NULL && (used+100 < BIG_BUF_SIZE))
    {
      nextt = t->next;
      local_irq_restore(flags);
      used += sprintf(bigbuf + used, "%-14s s: %6lu.%06lu e: %6lu.%06lu "
                      "d: %6li us data: 0x%08lX"
/*                      " func: 0x%08lX" */
                      "\n",
                      t->name,
                      (unsigned long)t->tv_set.tv_sec,
                      (unsigned long)t->tv_set.tv_usec,
                      (unsigned long)t->tv_expires.tv_sec,
                      (unsigned long)t->tv_expires.tv_usec,
                      t->delay_us,
                      t->data
/*                      , t->function */
                      );
      local_irq_disable();
      if (t->next != nextt)
      {
        printk(KERN_WARNING "timer removed!\n");
      }
      t = nextt;
    }
    local_irq_restore(flags);
  }

  if (used - offset < len)
  {
    len = used - offset;
  }

  memcpy(buf, bigbuf + offset, len);
  *start = buf;
  *eof = 1;

  return len;
}
#endif /* PROC_FS */

#ifdef FAST_TIMER_TEST
static volatile unsigned long i = 0;
static volatile int num_test_timeout = 0;
static struct fast_timer tr[10];
static int exp_num[10];

static struct timeval tv_exp[100];

static void test_timeout(unsigned long data)
{
  do_gettimeofday_fast(&tv_exp[data]);
  exp_num[data] = num_test_timeout;

  num_test_timeout++;
}

static void test_timeout1(unsigned long data)
{
  do_gettimeofday_fast(&tv_exp[data]);
  exp_num[data] = num_test_timeout;
  if (data < 7)
  {
    start_one_shot_timer(&tr[i], test_timeout1, i, 1000, "timeout1");
    i++;
  }
  num_test_timeout++;
}

DP(
static char buf0[2000];
static char buf1[2000];
static char buf2[2000];
static char buf3[2000];
static char buf4[2000];
);

static char buf5[6000];
static int j_u[1000];

static void fast_timer_test(void)
{
  int prev_num;
  int j;

  struct timeval tv, tv0, tv1, tv2;

  printk("fast_timer_test() start\n");
  do_gettimeofday_fast(&tv);

  for (j = 0; j < 1000; j++)
  {
    j_u[j] = GET_JIFFIES_USEC();
  }
  for (j = 0; j < 100; j++)
  {
    do_gettimeofday_fast(&tv_exp[j]);
  }
  printk("fast_timer_test() %is %06i\n", tv.tv_sec, tv.tv_usec);

  for (j = 0; j < 1000; j++)
  {
    printk("%i %i %i %i %i\n",j_u[j], j_u[j+1], j_u[j+2], j_u[j+3], j_u[j+4]);
    j += 4;
  }
  for (j = 0; j < 100; j++)
  {
    printk("%i.%i %i.%i %i.%i %i.%i %i.%i\n",
           tv_exp[j].tv_sec,tv_exp[j].tv_usec,
           tv_exp[j+1].tv_sec,tv_exp[j+1].tv_usec,
           tv_exp[j+2].tv_sec,tv_exp[j+2].tv_usec,
           tv_exp[j+3].tv_sec,tv_exp[j+3].tv_usec,
           tv_exp[j+4].tv_sec,tv_exp[j+4].tv_usec);
    j += 4;
  }
  do_gettimeofday_fast(&tv0);
  start_one_shot_timer(&tr[i], test_timeout, i, 50000, "test0");
  DP(proc_fasttimer_read(buf0, NULL, 0, 0, 0));
  i++;
  start_one_shot_timer(&tr[i], test_timeout, i, 70000, "test1");
  DP(proc_fasttimer_read(buf1, NULL, 0, 0, 0));
  i++;
  start_one_shot_timer(&tr[i], test_timeout, i, 40000, "test2");
  DP(proc_fasttimer_read(buf2, NULL, 0, 0, 0));
  i++;
  start_one_shot_timer(&tr[i], test_timeout, i, 60000, "test3");
  DP(proc_fasttimer_read(buf3, NULL, 0, 0, 0));
  i++;
  start_one_shot_timer(&tr[i], test_timeout1, i, 55000, "test4xx");
  DP(proc_fasttimer_read(buf4, NULL, 0, 0, 0));
  i++;
  do_gettimeofday_fast(&tv1);

  proc_fasttimer_read(buf5, NULL, 0, 0, 0);

  prev_num = num_test_timeout;
  while (num_test_timeout < i)
  {
    if (num_test_timeout != prev_num)
    {
      prev_num = num_test_timeout;
    }
  }
  do_gettimeofday_fast(&tv2);
  printk("Timers started    %is %06i\n", tv0.tv_sec, tv0.tv_usec);
  printk("Timers started at %is %06i\n", tv1.tv_sec, tv1.tv_usec);
  printk("Timers done       %is %06i\n", tv2.tv_sec, tv2.tv_usec);
  DP(printk("buf0:\n");
     printk(buf0);
     printk("buf1:\n");
     printk(buf1);
     printk("buf2:\n");
     printk(buf2);
     printk("buf3:\n");
     printk(buf3);
     printk("buf4:\n");
     printk(buf4);
  );
  printk("buf5:\n");
  printk(buf5);

  printk("timers set:\n");
  for(j = 0; j<i; j++)
  {
    struct fast_timer *t = &tr[j];
    printk("%-10s set: %6is %06ius exp: %6is %06ius "
           "data: 0x%08X func: 0x%08X\n",
           t->name,
           t->tv_set.tv_sec,
           t->tv_set.tv_usec,
           t->tv_expires.tv_sec,
           t->tv_expires.tv_usec,
           t->data,
           t->function
           );

    printk("           del: %6ius     did exp: %6is %06ius as #%i error: %6li\n",
           t->delay_us,
           tv_exp[j].tv_sec,
           tv_exp[j].tv_usec,
           exp_num[j],
           (tv_exp[j].tv_sec - t->tv_expires.tv_sec)*1000000 + tv_exp[j].tv_usec - t->tv_expires.tv_usec);
  }
  proc_fasttimer_read(buf5, NULL, 0, 0, 0);
  printk("buf5 after all done:\n");
  printk(buf5);
  printk("fast_timer_test() done\n");
}
#endif


void fast_timer_init(void)
{
  /* For some reason, request_irq() hangs when called froom time_init() */
  if (!fast_timer_is_init)
  {
#if 0 && defined(FAST_TIMER_TEST)
    int i;
#endif

    printk(KERN_INFO "fast_timer_init()\n");

#if 0 && defined(FAST_TIMER_TEST)
    for (i = 0; i <= TIMER0_DIV; i++)
    {
      /* We must be careful not to get overflow... */
      printk("%3i %6u\n", i, timer0_value_us[i]);
    }
#endif
#ifdef CONFIG_PROC_FS
   if ((fasttimer_proc_entry = create_proc_entry( "fasttimer", 0, 0 )))
     fasttimer_proc_entry->read_proc = proc_fasttimer_read;
#endif /* PROC_FS */
    if(request_irq(TIMER1_IRQ_NBR, timer1_handler, 0,
                   "fast timer int", NULL))
    {
      printk("err: timer1 irq\n");
    }
    fast_timer_is_init = 1;
#ifdef FAST_TIMER_TEST
    printk("do test\n");
    fast_timer_test();
#endif
  }
}