forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathrtc.c
1311 lines (1120 loc) · 30.9 KB
/
rtc.c
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
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Real Time Clock interface for Linux
*
* Copyright (C) 1996 Paul Gortmaker
*
* This driver allows use of the real time clock (built into
* nearly all computers) from user space. It exports the /dev/rtc
* interface supporting various ioctl() and also the
* /proc/driver/rtc pseudo-file for status information.
*
* The ioctls can be used to set the interrupt behaviour and
* generation rate from the RTC via IRQ 8. Then the /dev/rtc
* interface can be used to make use of these timer interrupts,
* be they interval or alarm based.
*
* The /dev/rtc interface will block on reads until an interrupt
* has been received. If a RTC interrupt has already happened,
* it will output an unsigned long and then block. The output value
* contains the interrupt status in the low byte and the number of
* interrupts since the last read in the remaining high bytes. The
* /dev/rtc interface can also be used with the select(2) call.
*
* Based on other minimal char device drivers, like Alan's
* watchdog, Ted's random, etc. etc.
*
* 1.07 Paul Gortmaker.
* 1.08 Miquel van Smoorenburg: disallow certain things on the
* DEC Alpha as the CMOS clock is also used for other things.
* 1.09 Nikita Schmidt: epoch support and some Alpha cleanup.
* 1.09a Pete Zaitcev: Sun SPARC
* 1.09b Jeff Garzik: Modularize, init cleanup
* 1.09c Jeff Garzik: SMP cleanup
* 1.10 Paul Barton-Davis: add support for async I/O
* 1.10a Andrea Arcangeli: Alpha updates
* 1.10b Andrew Morton: SMP lock fix
* 1.10c Cesar Barros: SMP locking fixes and cleanup
* 1.10d Paul Gortmaker: delete paranoia check in rtc_exit
* 1.10e Maciej W. Rozycki: Handle DECstation's year weirdness.
* 1.11 Takashi Iwai: Kernel access functions
* rtc_register/rtc_unregister/rtc_control
* 1.11a Daniele Bellucci: Audit create_proc_read_entry in rtc_init
* 1.12 Venkatesh Pallipadi: Hooks for emulating rtc on HPET base-timer
* CONFIG_HPET_EMULATE_RTC
* 1.12a Maciej W. Rozycki: Handle memory-mapped chips properly.
* 1.12ac Alan Cox: Allow read access to the day of week register
* 1.12b David John: Remove calls to the BKL.
*/
#define RTC_VERSION "1.12b"
/*
* Note that *all* calls to CMOS_READ and CMOS_WRITE are done with
* interrupts disabled. Due to the index-port/data-port (0x70/0x71)
* design of the RTC, we don't want two different things trying to
* get to it at once. (e.g. the periodic 11 min sync from
* kernel/time/ntp.c vs. this driver.)
*/
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <linux/mc146818rtc.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <linux/sched/signal.h>
#include <linux/sysctl.h>
#include <linux/wait.h>
#include <linux/bcd.h>
#include <linux/delay.h>
#include <linux/uaccess.h>
#include <linux/ratelimit.h>
#include <asm/current.h>
#ifdef CONFIG_X86
#include <asm/hpet.h>
#endif
#ifdef CONFIG_SPARC32
#include <linux/of.h>
#include <linux/of_device.h>
#include <asm/io.h>
static unsigned long rtc_port;
static int rtc_irq;
#endif
#ifdef CONFIG_HPET_EMULATE_RTC
#undef RTC_IRQ
#endif
#ifdef RTC_IRQ
static int rtc_has_irq = 1;
#endif
#ifndef CONFIG_HPET_EMULATE_RTC
#define is_hpet_enabled() 0
#define hpet_set_alarm_time(hrs, min, sec) 0
#define hpet_set_periodic_freq(arg) 0
#define hpet_mask_rtc_irq_bit(arg) 0
#define hpet_set_rtc_irq_bit(arg) 0
#define hpet_rtc_timer_init() do { } while (0)
#define hpet_rtc_dropped_irq() 0
#define hpet_register_irq_handler(h) ({ 0; })
#define hpet_unregister_irq_handler(h) ({ 0; })
#ifdef RTC_IRQ
static irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
{
return 0;
}
#endif
#endif
/*
* We sponge a minor off of the misc major. No need slurping
* up another valuable major dev number for this. If you add
* an ioctl, make sure you don't conflict with SPARC's RTC
* ioctls.
*/
static struct fasync_struct *rtc_async_queue;
static DECLARE_WAIT_QUEUE_HEAD(rtc_wait);
#ifdef RTC_IRQ
static void rtc_dropped_irq(struct timer_list *unused);
static DEFINE_TIMER(rtc_irq_timer, rtc_dropped_irq);
#endif
static ssize_t rtc_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos);
static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
static void rtc_get_rtc_time(struct rtc_time *rtc_tm);
#ifdef RTC_IRQ
static __poll_t rtc_poll(struct file *file, poll_table *wait);
#endif
static void get_rtc_alm_time(struct rtc_time *alm_tm);
#ifdef RTC_IRQ
static void set_rtc_irq_bit_locked(unsigned char bit);
static void mask_rtc_irq_bit_locked(unsigned char bit);
static inline void set_rtc_irq_bit(unsigned char bit)
{
spin_lock_irq(&rtc_lock);
set_rtc_irq_bit_locked(bit);
spin_unlock_irq(&rtc_lock);
}
static void mask_rtc_irq_bit(unsigned char bit)
{
spin_lock_irq(&rtc_lock);
mask_rtc_irq_bit_locked(bit);
spin_unlock_irq(&rtc_lock);
}
#endif
#ifdef CONFIG_PROC_FS
static int rtc_proc_show(struct seq_file *seq, void *v);
#endif
/*
* Bits in rtc_status. (6 bits of room for future expansion)
*/
#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
#define RTC_TIMER_ON 0x02 /* missed irq timer active */
/*
* rtc_status is never changed by rtc_interrupt, and ioctl/open/close is
* protected by the spin lock rtc_lock. However, ioctl can still disable the
* timer in rtc_status and then with del_timer after the interrupt has read
* rtc_status but before mod_timer is called, which would then reenable the
* timer (but you would need to have an awful timing before you'd trip on it)
*/
static unsigned long rtc_status; /* bitmapped status byte. */
static unsigned long rtc_freq; /* Current periodic IRQ rate */
static unsigned long rtc_irq_data; /* our output to the world */
static unsigned long rtc_max_user_freq = 64; /* > this, need CAP_SYS_RESOURCE */
/*
* If this driver ever becomes modularised, it will be really nice
* to make the epoch retain its value across module reload...
*/
static unsigned long epoch = 1900; /* year corresponding to 0x00 */
static const unsigned char days_in_mo[] =
{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
/*
* Returns true if a clock update is in progress
*/
static inline unsigned char rtc_is_updating(void)
{
unsigned long flags;
unsigned char uip;
spin_lock_irqsave(&rtc_lock, flags);
uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
spin_unlock_irqrestore(&rtc_lock, flags);
return uip;
}
#ifdef RTC_IRQ
/*
* A very tiny interrupt handler. It runs with interrupts disabled,
* but there is possibility of conflicting with the set_rtc_mmss()
* call (the rtc irq and the timer irq can easily run at the same
* time in two different CPUs). So we need to serialize
* accesses to the chip with the rtc_lock spinlock that each
* architecture should implement in the timer code.
* (See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.)
*/
static irqreturn_t rtc_interrupt(int irq, void *dev_id)
{
/*
* Can be an alarm interrupt, update complete interrupt,
* or a periodic interrupt. We store the status in the
* low byte and the number of interrupts received since
* the last read in the remainder of rtc_irq_data.
*/
spin_lock(&rtc_lock);
rtc_irq_data += 0x100;
rtc_irq_data &= ~0xff;
if (is_hpet_enabled()) {
/*
* In this case it is HPET RTC interrupt handler
* calling us, with the interrupt information
* passed as arg1, instead of irq.
*/
rtc_irq_data |= (unsigned long)irq & 0xF0;
} else {
rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);
}
if (rtc_status & RTC_TIMER_ON)
mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);
spin_unlock(&rtc_lock);
wake_up_interruptible(&rtc_wait);
kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
return IRQ_HANDLED;
}
#endif
/*
* sysctl-tuning infrastructure.
*/
static struct ctl_table rtc_table[] = {
{
.procname = "max-user-freq",
.data = &rtc_max_user_freq,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{ }
};
static struct ctl_table rtc_root[] = {
{
.procname = "rtc",
.mode = 0555,
.child = rtc_table,
},
{ }
};
static struct ctl_table dev_root[] = {
{
.procname = "dev",
.mode = 0555,
.child = rtc_root,
},
{ }
};
static struct ctl_table_header *sysctl_header;
static int __init init_sysctl(void)
{
sysctl_header = register_sysctl_table(dev_root);
return 0;
}
static void __exit cleanup_sysctl(void)
{
unregister_sysctl_table(sysctl_header);
}
/*
* Now all the various file operations that we export.
*/
static ssize_t rtc_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
#ifndef RTC_IRQ
return -EIO;
#else
DECLARE_WAITQUEUE(wait, current);
unsigned long data;
ssize_t retval;
if (rtc_has_irq == 0)
return -EIO;
/*
* Historically this function used to assume that sizeof(unsigned long)
* is the same in userspace and kernelspace. This lead to problems
* for configurations with multiple ABIs such a the MIPS o32 and 64
* ABIs supported on the same kernel. So now we support read of both
* 4 and 8 bytes and assume that's the sizeof(unsigned long) in the
* userspace ABI.
*/
if (count != sizeof(unsigned int) && count != sizeof(unsigned long))
return -EINVAL;
add_wait_queue(&rtc_wait, &wait);
do {
/* First make it right. Then make it fast. Putting this whole
* block within the parentheses of a while would be too
* confusing. And no, xchg() is not the answer. */
__set_current_state(TASK_INTERRUPTIBLE);
spin_lock_irq(&rtc_lock);
data = rtc_irq_data;
rtc_irq_data = 0;
spin_unlock_irq(&rtc_lock);
if (data != 0)
break;
if (file->f_flags & O_NONBLOCK) {
retval = -EAGAIN;
goto out;
}
if (signal_pending(current)) {
retval = -ERESTARTSYS;
goto out;
}
schedule();
} while (1);
if (count == sizeof(unsigned int)) {
retval = put_user(data,
(unsigned int __user *)buf) ?: sizeof(int);
} else {
retval = put_user(data,
(unsigned long __user *)buf) ?: sizeof(long);
}
if (!retval)
retval = count;
out:
__set_current_state(TASK_RUNNING);
remove_wait_queue(&rtc_wait, &wait);
return retval;
#endif
}
static int rtc_do_ioctl(unsigned int cmd, unsigned long arg, int kernel)
{
struct rtc_time wtime;
#ifdef RTC_IRQ
if (rtc_has_irq == 0) {
switch (cmd) {
case RTC_AIE_OFF:
case RTC_AIE_ON:
case RTC_PIE_OFF:
case RTC_PIE_ON:
case RTC_UIE_OFF:
case RTC_UIE_ON:
case RTC_IRQP_READ:
case RTC_IRQP_SET:
return -EINVAL;
}
}
#endif
switch (cmd) {
#ifdef RTC_IRQ
case RTC_AIE_OFF: /* Mask alarm int. enab. bit */
{
mask_rtc_irq_bit(RTC_AIE);
return 0;
}
case RTC_AIE_ON: /* Allow alarm interrupts. */
{
set_rtc_irq_bit(RTC_AIE);
return 0;
}
case RTC_PIE_OFF: /* Mask periodic int. enab. bit */
{
/* can be called from isr via rtc_control() */
unsigned long flags;
spin_lock_irqsave(&rtc_lock, flags);
mask_rtc_irq_bit_locked(RTC_PIE);
if (rtc_status & RTC_TIMER_ON) {
rtc_status &= ~RTC_TIMER_ON;
del_timer(&rtc_irq_timer);
}
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
case RTC_PIE_ON: /* Allow periodic ints */
{
/* can be called from isr via rtc_control() */
unsigned long flags;
/*
* We don't really want Joe User enabling more
* than 64Hz of interrupts on a multi-user machine.
*/
if (!kernel && (rtc_freq > rtc_max_user_freq) &&
(!capable(CAP_SYS_RESOURCE)))
return -EACCES;
spin_lock_irqsave(&rtc_lock, flags);
if (!(rtc_status & RTC_TIMER_ON)) {
mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq +
2*HZ/100);
rtc_status |= RTC_TIMER_ON;
}
set_rtc_irq_bit_locked(RTC_PIE);
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
case RTC_UIE_OFF: /* Mask ints from RTC updates. */
{
mask_rtc_irq_bit(RTC_UIE);
return 0;
}
case RTC_UIE_ON: /* Allow ints for RTC updates. */
{
set_rtc_irq_bit(RTC_UIE);
return 0;
}
#endif
case RTC_ALM_READ: /* Read the present alarm time */
{
/*
* This returns a struct rtc_time. Reading >= 0xc0
* means "don't care" or "match all". Only the tm_hour,
* tm_min, and tm_sec values are filled in.
*/
memset(&wtime, 0, sizeof(struct rtc_time));
get_rtc_alm_time(&wtime);
break;
}
case RTC_ALM_SET: /* Store a time into the alarm */
{
/*
* This expects a struct rtc_time. Writing 0xff means
* "don't care" or "match all". Only the tm_hour,
* tm_min and tm_sec are used.
*/
unsigned char hrs, min, sec;
struct rtc_time alm_tm;
if (copy_from_user(&alm_tm, (struct rtc_time __user *)arg,
sizeof(struct rtc_time)))
return -EFAULT;
hrs = alm_tm.tm_hour;
min = alm_tm.tm_min;
sec = alm_tm.tm_sec;
spin_lock_irq(&rtc_lock);
if (hpet_set_alarm_time(hrs, min, sec)) {
/*
* Fallthru and set alarm time in CMOS too,
* so that we will get proper value in RTC_ALM_READ
*/
}
if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) ||
RTC_ALWAYS_BCD) {
if (sec < 60)
sec = bin2bcd(sec);
else
sec = 0xff;
if (min < 60)
min = bin2bcd(min);
else
min = 0xff;
if (hrs < 24)
hrs = bin2bcd(hrs);
else
hrs = 0xff;
}
CMOS_WRITE(hrs, RTC_HOURS_ALARM);
CMOS_WRITE(min, RTC_MINUTES_ALARM);
CMOS_WRITE(sec, RTC_SECONDS_ALARM);
spin_unlock_irq(&rtc_lock);
return 0;
}
case RTC_RD_TIME: /* Read the time/date from RTC */
{
memset(&wtime, 0, sizeof(struct rtc_time));
rtc_get_rtc_time(&wtime);
break;
}
case RTC_SET_TIME: /* Set the RTC */
{
struct rtc_time rtc_tm;
unsigned char mon, day, hrs, min, sec, leap_yr;
unsigned char save_control, save_freq_select;
unsigned int yrs;
#ifdef CONFIG_MACH_DECSTATION
unsigned int real_yrs;
#endif
if (!capable(CAP_SYS_TIME))
return -EACCES;
if (copy_from_user(&rtc_tm, (struct rtc_time __user *)arg,
sizeof(struct rtc_time)))
return -EFAULT;
yrs = rtc_tm.tm_year + 1900;
mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
day = rtc_tm.tm_mday;
hrs = rtc_tm.tm_hour;
min = rtc_tm.tm_min;
sec = rtc_tm.tm_sec;
if (yrs < 1970)
return -EINVAL;
leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
if ((mon > 12) || (day == 0))
return -EINVAL;
if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
return -EINVAL;
if ((hrs >= 24) || (min >= 60) || (sec >= 60))
return -EINVAL;
yrs -= epoch;
if (yrs > 255) /* They are unsigned */
return -EINVAL;
spin_lock_irq(&rtc_lock);
#ifdef CONFIG_MACH_DECSTATION
real_yrs = yrs;
yrs = 72;
/*
* We want to keep the year set to 73 until March
* for non-leap years, so that Feb, 29th is handled
* correctly.
*/
if (!leap_yr && mon < 3) {
real_yrs--;
yrs = 73;
}
#endif
/* These limits and adjustments are independent of
* whether the chip is in binary mode or not.
*/
if (yrs > 169) {
spin_unlock_irq(&rtc_lock);
return -EINVAL;
}
if (yrs >= 100)
yrs -= 100;
if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
|| RTC_ALWAYS_BCD) {
sec = bin2bcd(sec);
min = bin2bcd(min);
hrs = bin2bcd(hrs);
day = bin2bcd(day);
mon = bin2bcd(mon);
yrs = bin2bcd(yrs);
}
save_control = CMOS_READ(RTC_CONTROL);
CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
#ifdef CONFIG_MACH_DECSTATION
CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
#endif
CMOS_WRITE(yrs, RTC_YEAR);
CMOS_WRITE(mon, RTC_MONTH);
CMOS_WRITE(day, RTC_DAY_OF_MONTH);
CMOS_WRITE(hrs, RTC_HOURS);
CMOS_WRITE(min, RTC_MINUTES);
CMOS_WRITE(sec, RTC_SECONDS);
CMOS_WRITE(save_control, RTC_CONTROL);
CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
spin_unlock_irq(&rtc_lock);
return 0;
}
#ifdef RTC_IRQ
case RTC_IRQP_READ: /* Read the periodic IRQ rate. */
{
return put_user(rtc_freq, (unsigned long __user *)arg);
}
case RTC_IRQP_SET: /* Set periodic IRQ rate. */
{
int tmp = 0;
unsigned char val;
/* can be called from isr via rtc_control() */
unsigned long flags;
/*
* The max we can do is 8192Hz.
*/
if ((arg < 2) || (arg > 8192))
return -EINVAL;
/*
* We don't really want Joe User generating more
* than 64Hz of interrupts on a multi-user machine.
*/
if (!kernel && (arg > rtc_max_user_freq) &&
!capable(CAP_SYS_RESOURCE))
return -EACCES;
while (arg > (1<<tmp))
tmp++;
/*
* Check that the input was really a power of 2.
*/
if (arg != (1<<tmp))
return -EINVAL;
rtc_freq = arg;
spin_lock_irqsave(&rtc_lock, flags);
if (hpet_set_periodic_freq(arg)) {
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
val = CMOS_READ(RTC_FREQ_SELECT) & 0xf0;
val |= (16 - tmp);
CMOS_WRITE(val, RTC_FREQ_SELECT);
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
#endif
case RTC_EPOCH_READ: /* Read the epoch. */
{
return put_user(epoch, (unsigned long __user *)arg);
}
case RTC_EPOCH_SET: /* Set the epoch. */
{
/*
* There were no RTC clocks before 1900.
*/
if (arg < 1900)
return -EINVAL;
if (!capable(CAP_SYS_TIME))
return -EACCES;
epoch = arg;
return 0;
}
default:
return -ENOTTY;
}
return copy_to_user((void __user *)arg,
&wtime, sizeof wtime) ? -EFAULT : 0;
}
static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
long ret;
ret = rtc_do_ioctl(cmd, arg, 0);
return ret;
}
/*
* We enforce only one user at a time here with the open/close.
* Also clear the previous interrupt data on an open, and clean
* up things on a close.
*/
static int rtc_open(struct inode *inode, struct file *file)
{
spin_lock_irq(&rtc_lock);
if (rtc_status & RTC_IS_OPEN)
goto out_busy;
rtc_status |= RTC_IS_OPEN;
rtc_irq_data = 0;
spin_unlock_irq(&rtc_lock);
return 0;
out_busy:
spin_unlock_irq(&rtc_lock);
return -EBUSY;
}
static int rtc_fasync(int fd, struct file *filp, int on)
{
return fasync_helper(fd, filp, on, &rtc_async_queue);
}
static int rtc_release(struct inode *inode, struct file *file)
{
#ifdef RTC_IRQ
unsigned char tmp;
if (rtc_has_irq == 0)
goto no_irq;
/*
* Turn off all interrupts once the device is no longer
* in use, and clear the data.
*/
spin_lock_irq(&rtc_lock);
if (!hpet_mask_rtc_irq_bit(RTC_PIE | RTC_AIE | RTC_UIE)) {
tmp = CMOS_READ(RTC_CONTROL);
tmp &= ~RTC_PIE;
tmp &= ~RTC_AIE;
tmp &= ~RTC_UIE;
CMOS_WRITE(tmp, RTC_CONTROL);
CMOS_READ(RTC_INTR_FLAGS);
}
if (rtc_status & RTC_TIMER_ON) {
rtc_status &= ~RTC_TIMER_ON;
del_timer(&rtc_irq_timer);
}
spin_unlock_irq(&rtc_lock);
no_irq:
#endif
spin_lock_irq(&rtc_lock);
rtc_irq_data = 0;
rtc_status &= ~RTC_IS_OPEN;
spin_unlock_irq(&rtc_lock);
return 0;
}
#ifdef RTC_IRQ
static __poll_t rtc_poll(struct file *file, poll_table *wait)
{
unsigned long l;
if (rtc_has_irq == 0)
return 0;
poll_wait(file, &rtc_wait, wait);
spin_lock_irq(&rtc_lock);
l = rtc_irq_data;
spin_unlock_irq(&rtc_lock);
if (l != 0)
return EPOLLIN | EPOLLRDNORM;
return 0;
}
#endif
/*
* The various file operations we support.
*/
static const struct file_operations rtc_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.read = rtc_read,
#ifdef RTC_IRQ
.poll = rtc_poll,
#endif
.unlocked_ioctl = rtc_ioctl,
.open = rtc_open,
.release = rtc_release,
.fasync = rtc_fasync,
};
static struct miscdevice rtc_dev = {
.minor = RTC_MINOR,
.name = "rtc",
.fops = &rtc_fops,
};
static resource_size_t rtc_size;
static struct resource * __init rtc_request_region(resource_size_t size)
{
struct resource *r;
if (RTC_IOMAPPED)
r = request_region(RTC_PORT(0), size, "rtc");
else
r = request_mem_region(RTC_PORT(0), size, "rtc");
if (r)
rtc_size = size;
return r;
}
static void rtc_release_region(void)
{
if (RTC_IOMAPPED)
release_region(RTC_PORT(0), rtc_size);
else
release_mem_region(RTC_PORT(0), rtc_size);
}
static int __init rtc_init(void)
{
#ifdef CONFIG_PROC_FS
struct proc_dir_entry *ent;
#endif
#if defined(__alpha__) || defined(__mips__)
unsigned int year, ctrl;
char *guess = NULL;
#endif
#ifdef CONFIG_SPARC32
struct device_node *ebus_dp;
struct platform_device *op;
#else
void *r;
#ifdef RTC_IRQ
irq_handler_t rtc_int_handler_ptr;
#endif
#endif
#ifdef CONFIG_SPARC32
for_each_node_by_name(ebus_dp, "ebus") {
struct device_node *dp;
for_each_child_of_node(ebus_dp, dp) {
if (of_node_name_eq(dp, "rtc")) {
op = of_find_device_by_node(dp);
if (op) {
rtc_port = op->resource[0].start;
rtc_irq = op->irqs[0];
goto found;
}
}
}
}
rtc_has_irq = 0;
printk(KERN_ERR "rtc_init: no PC rtc found\n");
return -EIO;
found:
if (!rtc_irq) {
rtc_has_irq = 0;
goto no_irq;
}
/*
* XXX Interrupt pin #7 in Espresso is shared between RTC and
* PCI Slot 2 INTA# (and some INTx# in Slot 1).
*/
if (request_irq(rtc_irq, rtc_interrupt, IRQF_SHARED, "rtc",
(void *)&rtc_port)) {
rtc_has_irq = 0;
printk(KERN_ERR "rtc: cannot register IRQ %d\n", rtc_irq);
return -EIO;
}
no_irq:
#else
r = rtc_request_region(RTC_IO_EXTENT);
/*
* If we've already requested a smaller range (for example, because
* PNPBIOS or ACPI told us how the device is configured), the request
* above might fail because it's too big.
*
* If so, request just the range we actually use.
*/
if (!r)
r = rtc_request_region(RTC_IO_EXTENT_USED);
if (!r) {
#ifdef RTC_IRQ
rtc_has_irq = 0;
#endif
printk(KERN_ERR "rtc: I/O resource %lx is not free.\n",
(long)(RTC_PORT(0)));
return -EIO;
}
#ifdef RTC_IRQ
if (is_hpet_enabled()) {
int err;
rtc_int_handler_ptr = hpet_rtc_interrupt;
err = hpet_register_irq_handler(rtc_interrupt);
if (err != 0) {
printk(KERN_WARNING "hpet_register_irq_handler failed "
"in rtc_init().");
return err;
}
} else {
rtc_int_handler_ptr = rtc_interrupt;
}
if (request_irq(RTC_IRQ, rtc_int_handler_ptr, 0, "rtc", NULL)) {
/* Yeah right, seeing as irq 8 doesn't even hit the bus. */
rtc_has_irq = 0;
printk(KERN_ERR "rtc: IRQ %d is not free.\n", RTC_IRQ);
rtc_release_region();
return -EIO;
}
hpet_rtc_timer_init();
#endif
#endif /* CONFIG_SPARC32 vs. others */
if (misc_register(&rtc_dev)) {
#ifdef RTC_IRQ
free_irq(RTC_IRQ, NULL);
hpet_unregister_irq_handler(rtc_interrupt);
rtc_has_irq = 0;
#endif
rtc_release_region();
return -ENODEV;
}
#ifdef CONFIG_PROC_FS
ent = proc_create_single("driver/rtc", 0, NULL, rtc_proc_show);
if (!ent)
printk(KERN_WARNING "rtc: Failed to register with procfs.\n");
#endif
#if defined(__alpha__) || defined(__mips__)
rtc_freq = HZ;
/* Each operating system on an Alpha uses its own epoch.
Let's try to guess which one we are using now. */
if (rtc_is_updating() != 0)
msleep(20);
spin_lock_irq(&rtc_lock);
year = CMOS_READ(RTC_YEAR);
ctrl = CMOS_READ(RTC_CONTROL);
spin_unlock_irq(&rtc_lock);
if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
year = bcd2bin(year); /* This should never happen... */
if (year < 20) {
epoch = 2000;
guess = "SRM (post-2000)";
} else if (year >= 20 && year < 48) {
epoch = 1980;
guess = "ARC console";
} else if (year >= 48 && year < 72) {
epoch = 1952;
guess = "Digital UNIX";
#if defined(__mips__)
} else if (year >= 72 && year < 74) {
epoch = 2000;
guess = "Digital DECstation";
#else
} else if (year >= 70) {
epoch = 1900;
guess = "Standard PC (1900)";
#endif
}
if (guess)
printk(KERN_INFO "rtc: %s epoch (%lu) detected\n",