Bootlin logo

Elixir Cross Referencer

   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
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
/*
 *	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.
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 *
 *	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(unsigned long data);

static DEFINE_TIMER(rtc_irq_timer, rtc_dropped_irq, 0, 0);
#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 unsigned int 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_open(struct inode *inode, struct file *file);
#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 */

#ifdef RTC_IRQ
/*
 * rtc_task_lock nests inside rtc_lock.
 */
static DEFINE_SPINLOCK(rtc_task_lock);
static rtc_task_t *rtc_callback;
#endif

/*
 *	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);

	/* Now do the rest of the actions */
	spin_lock(&rtc_task_lock);
	if (rtc_callback)
		rtc_callback->func(rtc_callback->private_data);
	spin_unlock(&rtc_task_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 unsigned int 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 POLLIN | POLLRDNORM;
	return 0;
}
#endif

int rtc_register(rtc_task_t *task)
{
#ifndef RTC_IRQ
	return -EIO;
#else
	if (task == NULL || task->func == NULL)
		return -EINVAL;
	spin_lock_irq(&rtc_lock);
	if (rtc_status & RTC_IS_OPEN) {
		spin_unlock_irq(&rtc_lock);
		return -EBUSY;
	}
	spin_lock(&rtc_task_lock);
	if (rtc_callback) {
		spin_unlock(&rtc_task_lock);
		spin_unlock_irq(&rtc_lock);
		return -EBUSY;
	}
	rtc_status |= RTC_IS_OPEN;
	rtc_callback = task;
	spin_unlock(&rtc_task_lock);
	spin_unlock_irq(&rtc_lock);
	return 0;
#endif
}
EXPORT_SYMBOL(rtc_register);

int rtc_unregister(rtc_task_t *task)
{
#ifndef RTC_IRQ
	return -EIO;
#else
	unsigned char tmp;

	spin_lock_irq(&rtc_lock);
	spin_lock(&rtc_task_lock);
	if (rtc_callback != task) {
		spin_unlock(&rtc_task_lock);
		spin_unlock_irq(&rtc_lock);
		return -ENXIO;
	}
	rtc_callback = NULL;

	/* disable controls */
	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);
	}
	rtc_status &= ~RTC_IS_OPEN;
	spin_unlock(&rtc_task_lock);
	spin_unlock_irq(&rtc_lock);
	return 0;
#endif
}
EXPORT_SYMBOL(rtc_unregister);

int rtc_control(rtc_task_t *task, unsigned int cmd, unsigned long arg)
{
#ifndef RTC_IRQ
	return -EIO;
#else
	unsigned long flags;
	if (cmd != RTC_PIE_ON && cmd != RTC_PIE_OFF && cmd != RTC_IRQP_SET)
		return -EINVAL;
	spin_lock_irqsave(&rtc_task_lock, flags);
	if (rtc_callback != task) {
		spin_unlock_irqrestore(&rtc_task_lock, flags);
		return -ENXIO;
	}
	spin_unlock_irqrestore(&rtc_task_lock, flags);
	return rtc_do_ioctl(cmd, arg, 1);
#endif
}
EXPORT_SYMBOL(rtc_control);

/*
 *	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,
};

#ifdef CONFIG_PROC_FS
static const struct file_operations rtc_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= rtc_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};
#endif

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 (dp = ebus_dp; dp; dp = dp->sibling) {
			if (!strcmp(dp->name, "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("driver/rtc", 0, NULL, &rtc_proc_fops);
	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",
			guess, epoch);
#endif
#ifdef RTC_IRQ
	if (rtc_has_irq == 0)
		goto no_irq2;

	spin_lock_irq(&rtc_lock);
	rtc_freq = 1024;
	if (!hpet_set_periodic_freq(rtc_freq)) {
		/*
		 * Initialize periodic frequency to CMOS reset default,
		 * which is 1024Hz
		 */
		CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT) & 0xF0) | 0x06),
			   RTC_FREQ_SELECT);
	}
	spin_unlock_irq(&rtc_lock);
no_irq2:
#endif

	(void) init_sysctl();

	printk(KERN_INFO "Real Time Clock Driver v" RTC_VERSION "\n");

	return 0;
}

static void __exit rtc_exit(void)
{
	cleanup_sysctl();
	remove_proc_entry("driver/rtc", NULL);
	misc_deregister(&rtc_dev);

#ifdef CONFIG_SPARC32
	if (rtc_has_irq)
		free_irq(rtc_irq, &rtc_port);
#else
	rtc_release_region();
#ifdef RTC_IRQ
	if (rtc_has_irq) {
		free_irq(RTC_IRQ, NULL);
		hpet_unregister_irq_handler(hpet_rtc_interrupt);
	}
#endif
#endif /* CONFIG_SPARC32 */
}

module_init(rtc_init);
module_exit(rtc_exit);

#ifdef RTC_IRQ
/*
 *	At IRQ rates >= 4096Hz, an interrupt may get lost altogether.
 *	(usually during an IDE disk interrupt, with IRQ unmasking off)
 *	Since the interrupt handler doesn't get called, the IRQ status
 *	byte doesn't get read, and the RTC stops generating interrupts.
 *	A timer is set, and will call this function if/when that happens.
 *	To get it out of this stalled state, we just read the status.
 *	At least a jiffy of interrupts (rtc_freq/HZ) will have been lost.
 *	(You *really* shouldn't be trying to use a non-realtime system
 *	for something that requires a steady > 1KHz signal anyways.)
 */

static void rtc_dropped_irq(unsigned long data)
{
	unsigned long freq;

	spin_lock_irq(&rtc_lock);

	if (hpet_rtc_dropped_irq()) {
		spin_unlock_irq(&rtc_lock);
		return;
	}

	/* Just in case someone disabled the timer from behind our back... */
	if (rtc_status & RTC_TIMER_ON)
		mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);

	rtc_irq_data += ((rtc_freq/HZ)<<8);
	rtc_irq_data &= ~0xff;
	rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);	/* restart */

	freq = rtc_freq;

	spin_unlock_irq(&rtc_lock);

	printk_ratelimited(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n",
			   freq);

	/* Now we have new data */
	wake_up_interruptible(&rtc_wait);

	kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
}
#endif

#ifdef CONFIG_PROC_FS
/*
 *	Info exported via "/proc/driver/rtc".
 */

static int rtc_proc_show(struct seq_file *seq, void *v)
{
#define YN(bit) ((ctrl & bit) ? "yes" : "no")
#define NY(bit) ((ctrl & bit) ? "no" : "yes")
	struct rtc_time tm;
	unsigned char batt, ctrl;
	unsigned long freq;

	spin_lock_irq(&rtc_lock);
	batt = CMOS_READ(RTC_VALID) & RTC_VRT;
	ctrl = CMOS_READ(RTC_CONTROL);
	freq = rtc_freq;
	spin_unlock_irq(&rtc_lock);


	rtc_get_rtc_time(&tm);

	/*
	 * There is no way to tell if the luser has the RTC set for local
	 * time or for Universal Standard Time (GMT). Probably local though.
	 */
	seq_printf(seq,
		   "rtc_time\t: %02d:%02d:%02d\n"
		   "rtc_date\t: %04d-%02d-%02d\n"
		   "rtc_epoch\t: %04lu\n",
		   tm.tm_hour, tm.tm_min, tm.tm_sec,
		   tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);

	get_rtc_alm_time(&tm);

	/*
	 * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
	 * match any value for that particular field. Values that are
	 * greater than a valid time, but less than 0xc0 shouldn't appear.
	 */
	seq_puts(seq, "alarm\t\t: ");
	if (tm.tm_hour <= 24)
		seq_printf(seq, "%02d:", tm.tm_hour);
	else
		seq_puts(seq, "**:");

	if (tm.tm_min <= 59)
		seq_printf(seq, "%02d:", tm.tm_min);
	else
		seq_puts(seq, "**:");

	if (tm.tm_sec <= 59)
		seq_printf(seq, "%02d\n", tm.tm_sec);
	else
		seq_puts(seq, "**\n");

	seq_printf(seq,
		   "DST_enable\t: %s\n"
		   "BCD\t\t: %s\n"
		   "24hr\t\t: %s\n"
		   "square_wave\t: %s\n"
		   "alarm_IRQ\t: %s\n"
		   "update_IRQ\t: %s\n"
		   "periodic_IRQ\t: %s\n"
		   "periodic_freq\t: %ld\n"
		   "batt_status\t: %s\n",
		   YN(RTC_DST_EN),
		   NY(RTC_DM_BINARY),
		   YN(RTC_24H),
		   YN(RTC_SQWE),
		   YN(RTC_AIE),
		   YN(RTC_UIE),
		   YN(RTC_PIE),
		   freq,
		   batt ? "okay" : "dead");

	return  0;
#undef YN
#undef NY
}

static int rtc_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, rtc_proc_show, NULL);
}
#endif

static void rtc_get_rtc_time(struct rtc_time *rtc_tm)
{
	unsigned long uip_watchdog = jiffies, flags;
	unsigned char ctrl;
#ifdef CONFIG_MACH_DECSTATION
	unsigned int real_year;
#endif

	/*
	 * read RTC once any update in progress is done. The update
	 * can take just over 2ms. We wait 20ms. There is no need to
	 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
	 * If you need to know *exactly* when a second has started, enable
	 * periodic update complete interrupts, (via ioctl) and then
	 * immediately read /dev/rtc which will block until you get the IRQ.
	 * Once the read clears, read the RTC time (again via ioctl). Easy.
	 */

	while (rtc_is_updating() != 0 &&
	       time_before(jiffies, uip_watchdog + 2*HZ/100))
		cpu_relax();

	/*
	 * Only the values that we read from the RTC are set. We leave
	 * tm_wday, tm_yday and tm_isdst untouched. Note that while the
	 * RTC has RTC_DAY_OF_WEEK, we should usually ignore it, as it is
	 * only updated by the RTC when initially set to a non-zero value.
	 */
	spin_lock_irqsave(&rtc_lock, flags);
	rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
	rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
	rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
	rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
	rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
	rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
	/* Only set from 2.6.16 onwards */
	rtc_tm->tm_wday = CMOS_READ(RTC_DAY_OF_WEEK);

#ifdef CONFIG_MACH_DECSTATION
	real_year = CMOS_READ(RTC_DEC_YEAR);
#endif
	ctrl = CMOS_READ(RTC_CONTROL);
	spin_unlock_irqrestore(&rtc_lock, flags);

	if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
		rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
		rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
		rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
		rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
		rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
		rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
		rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
	}

#ifdef CONFIG_MACH_DECSTATION
	rtc_tm->tm_year += real_year - 72;
#endif

	/*
	 * Account for differences between how the RTC uses the values
	 * and how they are defined in a struct rtc_time;
	 */
	rtc_tm->tm_year += epoch - 1900;
	if (rtc_tm->tm_year <= 69)
		rtc_tm->tm_year += 100;

	rtc_tm->tm_mon--;
}

static void get_rtc_alm_time(struct rtc_time *alm_tm)
{
	unsigned char ctrl;

	/*
	 * Only the values that we read from the RTC are set. That
	 * means only tm_hour, tm_min, and tm_sec.
	 */
	spin_lock_irq(&rtc_lock);
	alm_tm->tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
	alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM);
	alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM);
	ctrl = CMOS_READ(RTC_CONTROL);
	spin_unlock_irq(&rtc_lock);

	if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
		alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec);
		alm_tm->tm_min = bcd2bin(alm_tm->tm_min);
		alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour);
	}
}

#ifdef RTC_IRQ
/*
 * Used to disable/enable interrupts for any one of UIE, AIE, PIE.
 * Rumour has it that if you frob the interrupt enable/disable
 * bits in RTC_CONTROL, you should read RTC_INTR_FLAGS, to
 * ensure you actually start getting interrupts. Probably for
 * compatibility with older/broken chipset RTC implementations.
 * We also clear out any old irq data after an ioctl() that
 * meddles with the interrupt enable/disable bits.
 */

static void mask_rtc_irq_bit_locked(unsigned char bit)
{
	unsigned char val;

	if (hpet_mask_rtc_irq_bit(bit))
		return;
	val = CMOS_READ(RTC_CONTROL);
	val &=  ~bit;
	CMOS_WRITE(val, RTC_CONTROL);
	CMOS_READ(RTC_INTR_FLAGS);

	rtc_irq_data = 0;
}

static void set_rtc_irq_bit_locked(unsigned char bit)
{
	unsigned char val;

	if (hpet_set_rtc_irq_bit(bit))
		return;
	val = CMOS_READ(RTC_CONTROL);
	val |= bit;
	CMOS_WRITE(val, RTC_CONTROL);
	CMOS_READ(RTC_INTR_FLAGS);

	rtc_irq_data = 0;
}
#endif

MODULE_AUTHOR("Paul Gortmaker");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(RTC_MINOR);