summaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/pcwd.c
blob: e1259adf09f97c04cc7acd98db8415e8ecc0f924 (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
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
/*
 * PC Watchdog Driver
 * by Ken Hollis (khollis@bitgate.com)
 *
 * Permission granted from Simon Machell (smachell@berkprod.com)
 * Written for the Linux Kernel, and GPLed by Ken Hollis
 *
 * 960107	Added request_region routines, modulized the whole thing.
 * 960108	Fixed end-of-file pointer (Thanks to Dan Hollis), added
 *		WD_TIMEOUT define.
 * 960216	Added eof marker on the file, and changed verbose messages.
 * 960716	Made functional and cosmetic changes to the source for
 *		inclusion in Linux 2.0.x kernels, thanks to Alan Cox.
 * 960717	Removed read/seek routines, replaced with ioctl.  Also, added
 *		check_region command due to Alan's suggestion.
 * 960821	Made changes to compile in newer 2.0.x kernels.  Added
 *		"cold reboot sense" entry.
 * 960825	Made a few changes to code, deleted some defines and made
 *		typedefs to replace them.  Made heartbeat reset only available
 *		via ioctl, and removed the write routine.
 * 960828	Added new items for PC Watchdog Rev.C card.
 * 960829	Changed around all of the IOCTLs, added new features,
 *		added watchdog disable/re-enable routines.  Added firmware
 *		version reporting.  Added read routine for temperature.
 *		Removed some extra defines, added an autodetect Revision
 *		routine.
 * 961006       Revised some documentation, fixed some cosmetic bugs.  Made
 *              drivers to panic the system if it's overheating at bootup.
 * 961118	Changed some verbiage on some of the output, tidied up
 *		code bits, and added compatibility to 2.1.x.
 * 970912       Enabled board on open and disable on close.
 * 971107	Took account of recent VFS changes (broke read).
 * 971210       Disable board on initialisation in case board already ticking.
 * 971222       Changed open/close for temperature handling
 *              Michael Meskes <meskes@debian.org>.
 * 980112       Used minor numbers from include/linux/miscdevice.h
 * 990403       Clear reset status after reading control status register in
 *              pcwd_showprevstate(). [Marc Boucher <marc@mbsi.ca>]
 * 990605	Made changes to code to support Firmware 1.22a, added
 *		fairly useless proc entry.
 * 990610	removed said useless proc code for the merge <alan>
 * 000403	Removed last traces of proc code. <davej>
 * 011214	Added nowayout module option to override
 *		CONFIG_WATCHDOG_NOWAYOUT <Matt_Domsch@dell.com>
 *              Added timeout module option to override default
 */

/*
 *	A bells and whistles driver is available from http://www.pcwd.de/
 *	More info available at http://www.berkprod.com/ or
 *	http://www.pcwatchdog.com/
 */

#include <linux/module.h>	/* For module specific items */
#include <linux/moduleparam.h>	/* For new moduleparam's */
#include <linux/types.h>	/* For standard types (like size_t) */
#include <linux/errno.h>	/* For the -ENODEV/... values */
#include <linux/kernel.h>	/* For printk/panic/... */
#include <linux/delay.h>	/* For mdelay function */
#include <linux/timer.h>	/* For timer related operations */
#include <linux/jiffies.h>	/* For jiffies stuff */
#include <linux/miscdevice.h>	/* For MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR) */
#include <linux/watchdog.h>	/* For the watchdog specific items */
#include <linux/reboot.h>	/* For kernel_power_off() */
#include <linux/init.h>		/* For __init/__exit/... */
#include <linux/fs.h>		/* For file operations */
#include <linux/isa.h>		/* For isa devices */
#include <linux/ioport.h>	/* For io-port access */
#include <linux/spinlock.h>	/* For spin_lock/spin_unlock/... */
#include <linux/uaccess.h>	/* For copy_to_user/put_user/... */
#include <linux/io.h>		/* For inb/outb/... */

/* Module and version information */
#define WATCHDOG_VERSION "1.20"
#define WATCHDOG_DATE "18 Feb 2007"
#define WATCHDOG_DRIVER_NAME "ISA-PC Watchdog"
#define WATCHDOG_NAME "pcwd"
#define PFX WATCHDOG_NAME ": "
#define DRIVER_VERSION WATCHDOG_DRIVER_NAME " driver, v" WATCHDOG_VERSION " (" WATCHDOG_DATE ")\n"
#define WD_VER WATCHDOG_VERSION " (" WATCHDOG_DATE ")"

/*
 * It should be noted that PCWD_REVISION_B was removed because A and B
 * are essentially the same types of card, with the exception that B
 * has temperature reporting.  Since I didn't receive a Rev.B card,
 * the Rev.B card is not supported.  (It's a good thing too, as they
 * are no longer in production.)
 */
#define	PCWD_REVISION_A		1
#define	PCWD_REVISION_C		2

/*
 * These are the auto-probe addresses available.
 *
 * Revision A only uses ports 0x270 and 0x370.  Revision C introduced 0x350.
 * Revision A has an address range of 2 addresses, while Revision C has 4.
 */
#define PCWD_ISA_NR_CARDS	3
static int pcwd_ioports[] = { 0x270, 0x350, 0x370, 0x000 };

/*
 * These are the defines that describe the control status bits for the
 * PCI-PC Watchdog card.
*/
/* Port 1 : Control Status #1 for the PC Watchdog card, revision A. */
#define WD_WDRST		0x01	/* Previously reset state */
#define WD_T110			0x02	/* Temperature overheat sense */
#define WD_HRTBT		0x04	/* Heartbeat sense */
#define WD_RLY2			0x08	/* External relay triggered */
#define WD_SRLY2		0x80	/* Software external relay triggered */
/* Port 1 : Control Status #1 for the PC Watchdog card, revision C. */
#define WD_REVC_WTRP		0x01	/* Watchdog Trip status */
#define WD_REVC_HRBT		0x02	/* Watchdog Heartbeat */
#define WD_REVC_TTRP		0x04	/* Temperature Trip status */
#define WD_REVC_RL2A		0x08	/* Relay 2 activated by
							on-board processor */
#define WD_REVC_RL1A		0x10	/* Relay 1 active */
#define WD_REVC_R2DS		0x40	/* Relay 2 disable */
#define WD_REVC_RLY2		0x80	/* Relay 2 activated? */
/* Port 2 : Control Status #2 */
#define WD_WDIS			0x10	/* Watchdog Disabled */
#define WD_ENTP			0x20	/* Watchdog Enable Temperature Trip */
#define WD_SSEL			0x40	/* Watchdog Switch Select
							(1:SW1 <-> 0:SW2) */
#define WD_WCMD			0x80	/* Watchdog Command Mode */

/* max. time we give an ISA watchdog card to process a command */
/* 500ms for each 4 bit response (according to spec.) */
#define ISA_COMMAND_TIMEOUT     1000

/* Watchdog's internal commands */
#define CMD_ISA_IDLE			0x00
#define CMD_ISA_VERSION_INTEGER		0x01
#define CMD_ISA_VERSION_TENTH		0x02
#define CMD_ISA_VERSION_HUNDRETH	0x03
#define CMD_ISA_VERSION_MINOR		0x04
#define CMD_ISA_SWITCH_SETTINGS		0x05
#define CMD_ISA_RESET_PC		0x06
#define CMD_ISA_ARM_0			0x07
#define CMD_ISA_ARM_30			0x08
#define CMD_ISA_ARM_60			0x09
#define CMD_ISA_DELAY_TIME_2SECS	0x0A
#define CMD_ISA_DELAY_TIME_4SECS	0x0B
#define CMD_ISA_DELAY_TIME_8SECS	0x0C
#define CMD_ISA_RESET_RELAYS		0x0D

/* Watchdog's Dip Switch heartbeat values */
static const int heartbeat_tbl [] = {
	20,	/* OFF-OFF-OFF	= 20 Sec  */
	40,	/* OFF-OFF-ON	= 40 Sec  */
	60,	/* OFF-ON-OFF	=  1 Min  */
	300,	/* OFF-ON-ON	=  5 Min  */
	600,	/* ON-OFF-OFF	= 10 Min  */
	1800,	/* ON-OFF-ON	= 30 Min  */
	3600,	/* ON-ON-OFF	=  1 Hour */
	7200,	/* ON-ON-ON	=  2 hour */
};

/*
 * We are using an kernel timer to do the pinging of the watchdog
 * every ~500ms. We try to set the internal heartbeat of the
 * watchdog to 2 ms.
 */

#define WDT_INTERVAL (HZ/2+1)

/* We can only use 1 card due to the /dev/watchdog restriction */
static int cards_found;

/* internal variables */
static atomic_t open_allowed = ATOMIC_INIT(1);
static char expect_close;
static int temp_panic;

/* this is private data for each ISA-PC watchdog card */
static struct {
	char fw_ver_str[6];		/* The cards firmware version */
	int revision;			/* The card's revision */
	int supports_temp;		/* Whether or not the card has
						a temperature device */
	int command_mode;		/* Whether or not the card is in
						command mode */
	int boot_status;		/* The card's boot status */
	int io_addr;			/* The cards I/O address */
	spinlock_t io_lock;		/* the lock for io operations */
	struct timer_list timer;	/* The timer that pings the watchdog */
	unsigned long next_heartbeat;	/* the next_heartbeat for the timer */
} pcwd_private;

/* module parameters */
#define QUIET	0	/* Default */
#define VERBOSE	1	/* Verbose */
#define DEBUG	2	/* print fancy stuff too */
static int debug = QUIET;
module_param(debug, int, 0);
MODULE_PARM_DESC(debug,
		"Debug level: 0=Quiet, 1=Verbose, 2=Debug (default=0)");

/* default heartbeat = delay-time from dip-switches */
#define WATCHDOG_HEARTBEAT 0
static int heartbeat = WATCHDOG_HEARTBEAT;
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2 <= heartbeat <= 7200 or 0=delay-time from dip-switches, default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");

static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout,
		"Watchdog cannot be stopped once started (default="
				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

/*
 *	Internal functions
 */

static int send_isa_command(int cmd)
{
	int i;
	int control_status;
	int port0, last_port0;	/* Double read for stabilising */

	if (debug >= DEBUG)
		printk(KERN_DEBUG PFX "sending following data cmd=0x%02x\n",
			cmd);

	/* The WCMD bit must be 1 and the command is only 4 bits in size */
	control_status = (cmd & 0x0F) | WD_WCMD;
	outb_p(control_status, pcwd_private.io_addr + 2);
	udelay(ISA_COMMAND_TIMEOUT);

	port0 = inb_p(pcwd_private.io_addr);
	for (i = 0; i < 25; ++i) {
		last_port0 = port0;
		port0 = inb_p(pcwd_private.io_addr);

		if (port0 == last_port0)
			break;	/* Data is stable */

		udelay(250);
	}

	if (debug >= DEBUG)
		printk(KERN_DEBUG PFX "received following data for cmd=0x%02x: port0=0x%02x last_port0=0x%02x\n",
			cmd, port0, last_port0);

	return port0;
}

static int set_command_mode(void)
{
	int i, found = 0, count = 0;

	/* Set the card into command mode */
	spin_lock(&pcwd_private.io_lock);
	while ((!found) && (count < 3)) {
		i = send_isa_command(CMD_ISA_IDLE);

		if (i == 0x00)
			found = 1;
		else if (i == 0xF3) {
			/* Card does not like what we've done to it */
			outb_p(0x00, pcwd_private.io_addr + 2);
			udelay(1200);	/* Spec says wait 1ms */
			outb_p(0x00, pcwd_private.io_addr + 2);
			udelay(ISA_COMMAND_TIMEOUT);
		}
		count++;
	}
	spin_unlock(&pcwd_private.io_lock);
	pcwd_private.command_mode = found;

	if (debug >= DEBUG)
		printk(KERN_DEBUG PFX "command_mode=%d\n",
				pcwd_private.command_mode);

	return(found);
}

static void unset_command_mode(void)
{
	/* Set the card into normal mode */
	spin_lock(&pcwd_private.io_lock);
	outb_p(0x00, pcwd_private.io_addr + 2);
	udelay(ISA_COMMAND_TIMEOUT);
	spin_unlock(&pcwd_private.io_lock);

	pcwd_private.command_mode = 0;

	if (debug >= DEBUG)
		printk(KERN_DEBUG PFX "command_mode=%d\n",
				pcwd_private.command_mode);
}

static inline void pcwd_check_temperature_support(void)
{
	if (inb(pcwd_private.io_addr) != 0xF0)
		pcwd_private.supports_temp = 1;
}

static inline void pcwd_get_firmware(void)
{
	int one, ten, hund, minor;

	strcpy(pcwd_private.fw_ver_str, "ERROR");

	if (set_command_mode()) {
		one = send_isa_command(CMD_ISA_VERSION_INTEGER);
		ten = send_isa_command(CMD_ISA_VERSION_TENTH);
		hund = send_isa_command(CMD_ISA_VERSION_HUNDRETH);
		minor = send_isa_command(CMD_ISA_VERSION_MINOR);
		sprintf(pcwd_private.fw_ver_str, "%c.%c%c%c",
					one, ten, hund, minor);
	}
	unset_command_mode();

	return;
}

static inline int pcwd_get_option_switches(void)
{
	int option_switches = 0;

	if (set_command_mode()) {
		/* Get switch settings */
		option_switches = send_isa_command(CMD_ISA_SWITCH_SETTINGS);
	}

	unset_command_mode();
	return(option_switches);
}

static void pcwd_show_card_info(void)
{
	int option_switches;

	/* Get some extra info from the hardware (in command/debug/diag mode) */
	if (pcwd_private.revision == PCWD_REVISION_A)
		printk(KERN_INFO PFX
			"ISA-PC Watchdog (REV.A) detected at port 0x%04x\n",
							pcwd_private.io_addr);
	else if (pcwd_private.revision == PCWD_REVISION_C) {
		pcwd_get_firmware();
		printk(KERN_INFO PFX "ISA-PC Watchdog (REV.C) detected at port 0x%04x (Firmware version: %s)\n",
			pcwd_private.io_addr, pcwd_private.fw_ver_str);
		option_switches = pcwd_get_option_switches();
		printk(KERN_INFO PFX "Option switches (0x%02x): Temperature Reset Enable=%s, Power On Delay=%s\n",
			option_switches,
			((option_switches & 0x10) ? "ON" : "OFF"),
			((option_switches & 0x08) ? "ON" : "OFF"));

		/* Reprogram internal heartbeat to 2 seconds */
		if (set_command_mode()) {
			send_isa_command(CMD_ISA_DELAY_TIME_2SECS);
			unset_command_mode();
		}
	}

	if (pcwd_private.supports_temp)
		printk(KERN_INFO PFX "Temperature Option Detected\n");

	if (pcwd_private.boot_status & WDIOF_CARDRESET)
		printk(KERN_INFO PFX "Previous reboot was caused by the card\n");

	if (pcwd_private.boot_status & WDIOF_OVERHEAT) {
		printk(KERN_EMERG PFX
			"Card senses a CPU Overheat. Panicking!\n");
		printk(KERN_EMERG PFX
			"CPU Overheat\n");
	}

	if (pcwd_private.boot_status == 0)
		printk(KERN_INFO PFX
			"No previous trip detected - Cold boot or reset\n");
}

static void pcwd_timer_ping(unsigned long data)
{
	int wdrst_stat;

	/* If we got a heartbeat pulse within the WDT_INTERVAL
	 * we agree to ping the WDT */
	if (time_before(jiffies, pcwd_private.next_heartbeat)) {
		/* Ping the watchdog */
		spin_lock(&pcwd_private.io_lock);
		if (pcwd_private.revision == PCWD_REVISION_A) {
			/*  Rev A cards are reset by setting the
			    WD_WDRST bit in register 1 */
			wdrst_stat = inb_p(pcwd_private.io_addr);
			wdrst_stat &= 0x0F;
			wdrst_stat |= WD_WDRST;

			outb_p(wdrst_stat, pcwd_private.io_addr + 1);
		} else {
			/* Re-trigger watchdog by writing to port 0 */
			outb_p(0x00, pcwd_private.io_addr);
		}

		/* Re-set the timer interval */
		mod_timer(&pcwd_private.timer, jiffies + WDT_INTERVAL);

		spin_unlock(&pcwd_private.io_lock);
	} else {
		printk(KERN_WARNING PFX
			"Heartbeat lost! Will not ping the watchdog\n");
	}
}

static int pcwd_start(void)
{
	int stat_reg;

	pcwd_private.next_heartbeat = jiffies + (heartbeat * HZ);

	/* Start the timer */
	mod_timer(&pcwd_private.timer, jiffies + WDT_INTERVAL);

	/* Enable the port */
	if (pcwd_private.revision == PCWD_REVISION_C) {
		spin_lock(&pcwd_private.io_lock);
		outb_p(0x00, pcwd_private.io_addr + 3);
		udelay(ISA_COMMAND_TIMEOUT);
		stat_reg = inb_p(pcwd_private.io_addr + 2);
		spin_unlock(&pcwd_private.io_lock);
		if (stat_reg & WD_WDIS) {
			printk(KERN_INFO PFX "Could not start watchdog\n");
			return -EIO;
		}
	}

	if (debug >= VERBOSE)
		printk(KERN_DEBUG PFX "Watchdog started\n");

	return 0;
}

static int pcwd_stop(void)
{
	int stat_reg;

	/* Stop the timer */
	del_timer(&pcwd_private.timer);

	/*  Disable the board  */
	if (pcwd_private.revision == PCWD_REVISION_C) {
		spin_lock(&pcwd_private.io_lock);
		outb_p(0xA5, pcwd_private.io_addr + 3);
		udelay(ISA_COMMAND_TIMEOUT);
		outb_p(0xA5, pcwd_private.io_addr + 3);
		udelay(ISA_COMMAND_TIMEOUT);
		stat_reg = inb_p(pcwd_private.io_addr + 2);
		spin_unlock(&pcwd_private.io_lock);
		if ((stat_reg & WD_WDIS) == 0) {
			printk(KERN_INFO PFX "Could not stop watchdog\n");
			return -EIO;
		}
	}

	if (debug >= VERBOSE)
		printk(KERN_DEBUG PFX "Watchdog stopped\n");

	return 0;
}

static int pcwd_keepalive(void)
{
	/* user land ping */
	pcwd_private.next_heartbeat = jiffies + (heartbeat * HZ);

	if (debug >= DEBUG)
		printk(KERN_DEBUG PFX "Watchdog keepalive signal send\n");

	return 0;
}

static int pcwd_set_heartbeat(int t)
{
	if (t < 2 || t > 7200) /* arbitrary upper limit */
		return -EINVAL;

	heartbeat = t;

	if (debug >= VERBOSE)
		printk(KERN_DEBUG PFX "New heartbeat: %d\n",
		       heartbeat);

	return 0;
}

static int pcwd_get_status(int *status)
{
	int control_status;

	*status = 0;
	spin_lock(&pcwd_private.io_lock);
	if (pcwd_private.revision == PCWD_REVISION_A)
		/* Rev A cards return status information from
		 * the base register, which is used for the
		 * temperature in other cards. */
		control_status = inb(pcwd_private.io_addr);
	else {
		/* Rev C cards return card status in the base
		 * address + 1 register. And use different bits
		 * to indicate a card initiated reset, and an
		 * over-temperature condition. And the reboot
		 * status can be reset. */
		control_status = inb(pcwd_private.io_addr + 1);
	}
	spin_unlock(&pcwd_private.io_lock);

	if (pcwd_private.revision == PCWD_REVISION_A) {
		if (control_status & WD_WDRST)
			*status |= WDIOF_CARDRESET;

		if (control_status & WD_T110) {
			*status |= WDIOF_OVERHEAT;
			if (temp_panic) {
				printk(KERN_INFO PFX
					"Temperature overheat trip!\n");
				kernel_power_off();
			}
		}
	} else {
		if (control_status & WD_REVC_WTRP)
			*status |= WDIOF_CARDRESET;

		if (control_status & WD_REVC_TTRP) {
			*status |= WDIOF_OVERHEAT;
			if (temp_panic) {
				printk(KERN_INFO PFX
					"Temperature overheat trip!\n");
				kernel_power_off();
			}
		}
	}

	return 0;
}

static int pcwd_clear_status(void)
{
	int control_status;

	if (pcwd_private.revision == PCWD_REVISION_C) {
		spin_lock(&pcwd_private.io_lock);

		if (debug >= VERBOSE)
			printk(KERN_INFO PFX
					"clearing watchdog trip status\n");

		control_status = inb_p(pcwd_private.io_addr + 1);

		if (debug >= DEBUG) {
			printk(KERN_DEBUG PFX "status was: 0x%02x\n",
				control_status);
			printk(KERN_DEBUG PFX "sending: 0x%02x\n",
				(control_status & WD_REVC_R2DS));
		}

		/* clear reset status & Keep Relay 2 disable state as it is */
		outb_p((control_status & WD_REVC_R2DS),
						pcwd_private.io_addr + 1);

		spin_unlock(&pcwd_private.io_lock);
	}
	return 0;
}

static int pcwd_get_temperature(int *temperature)
{
	/* check that port 0 gives temperature info and no command results */
	if (pcwd_private.command_mode)
		return -1;

	*temperature = 0;
	if (!pcwd_private.supports_temp)
		return -ENODEV;

	/*
	 * Convert celsius to fahrenheit, since this was
	 * the decided 'standard' for this return value.
	 */
	spin_lock(&pcwd_private.io_lock);
	*temperature = ((inb(pcwd_private.io_addr)) * 9 / 5) + 32;
	spin_unlock(&pcwd_private.io_lock);

	if (debug >= DEBUG) {
		printk(KERN_DEBUG PFX "temperature is: %d F\n",
			*temperature);
	}

	return 0;
}

/*
 *	/dev/watchdog handling
 */

static long pcwd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	int rv;
	int status;
	int temperature;
	int new_heartbeat;
	int __user *argp = (int __user *)arg;
	static struct watchdog_info ident = {
		.options =		WDIOF_OVERHEAT |
					WDIOF_CARDRESET |
					WDIOF_KEEPALIVEPING |
					WDIOF_SETTIMEOUT |
					WDIOF_MAGICCLOSE,
		.firmware_version =	1,
		.identity =		"PCWD",
	};

	switch (cmd) {
	default:
		return -ENOTTY;

	case WDIOC_GETSUPPORT:
		if (copy_to_user(argp, &ident, sizeof(ident)))
			return -EFAULT;
		return 0;

	case WDIOC_GETSTATUS:
		pcwd_get_status(&status);
		return put_user(status, argp);

	case WDIOC_GETBOOTSTATUS:
		return put_user(pcwd_private.boot_status, argp);

	case WDIOC_GETTEMP:
		if (pcwd_get_temperature(&temperature))
			return -EFAULT;

		return put_user(temperature, argp);

	case WDIOC_SETOPTIONS:
		if (pcwd_private.revision == PCWD_REVISION_C) {
			if (get_user(rv, argp))
				return -EFAULT;

			if (rv & WDIOS_DISABLECARD) {
				status = pcwd_stop();
				if (status < 0)
					return status;
			}
			if (rv & WDIOS_ENABLECARD) {
				status = pcwd_start();
				if (status < 0)
					return status;
			}
			if (rv & WDIOS_TEMPPANIC)
				temp_panic = 1;
		}
		return -EINVAL;

	case WDIOC_KEEPALIVE:
		pcwd_keepalive();
		return 0;

	case WDIOC_SETTIMEOUT:
		if (get_user(new_heartbeat, argp))
			return -EFAULT;

		if (pcwd_set_heartbeat(new_heartbeat))
			return -EINVAL;

		pcwd_keepalive();
		/* Fall */

	case WDIOC_GETTIMEOUT:
		return put_user(heartbeat, argp);
	}

	return 0;
}

static ssize_t pcwd_write(struct file *file, const char __user *buf, size_t len,
			  loff_t *ppos)
{
	if (len) {
		if (!nowayout) {
			size_t i;

			/* In case it was set long ago */
			expect_close = 0;

			for (i = 0; i != len; i++) {
				char c;

				if (get_user(c, buf + i))
					return -EFAULT;
				if (c == 'V')
					expect_close = 42;
			}
		}
		pcwd_keepalive();
	}
	return len;
}

static int pcwd_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(0, &open_allowed))
		return -EBUSY;
	if (nowayout)
		__module_get(THIS_MODULE);
	/* Activate */
	pcwd_start();
	pcwd_keepalive();
	return nonseekable_open(inode, file);
}

static int pcwd_close(struct inode *inode, struct file *file)
{
	if (expect_close == 42)
		pcwd_stop();
	else {
		printk(KERN_CRIT PFX
			"Unexpected close, not stopping watchdog!\n");
		pcwd_keepalive();
	}
	expect_close = 0;
	clear_bit(0, &open_allowed);
	return 0;
}

/*
 *	/dev/temperature handling
 */

static ssize_t pcwd_temp_read(struct file *file, char __user *buf, size_t count,
			 loff_t *ppos)
{
	int temperature;

	if (pcwd_get_temperature(&temperature))
		return -EFAULT;

	if (copy_to_user(buf, &temperature, 1))
		return -EFAULT;

	return 1;
}

static int pcwd_temp_open(struct inode *inode, struct file *file)
{
	if (!pcwd_private.supports_temp)
		return -ENODEV;

	return nonseekable_open(inode, file);
}

static int pcwd_temp_close(struct inode *inode, struct file *file)
{
	return 0;
}

/*
 *	Kernel Interfaces
 */

static const struct file_operations pcwd_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= pcwd_write,
	.unlocked_ioctl	= pcwd_ioctl,
	.open		= pcwd_open,
	.release	= pcwd_close,
};

static struct miscdevice pcwd_miscdev = {
	.minor =	WATCHDOG_MINOR,
	.name =		"watchdog",
	.fops =		&pcwd_fops,
};

static const struct file_operations pcwd_temp_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.read		= pcwd_temp_read,
	.open		= pcwd_temp_open,
	.release	= pcwd_temp_close,
};

static struct miscdevice temp_miscdev = {
	.minor =	TEMP_MINOR,
	.name =		"temperature",
	.fops =		&pcwd_temp_fops,
};

/*
 *	Init & exit routines
 */

static inline int get_revision(void)
{
	int r = PCWD_REVISION_C;

	spin_lock(&pcwd_private.io_lock);
	/* REV A cards use only 2 io ports; test
	 * presumes a floating bus reads as 0xff. */
	if ((inb(pcwd_private.io_addr + 2) == 0xFF) ||
	    (inb(pcwd_private.io_addr + 3) == 0xFF))
		r = PCWD_REVISION_A;
	spin_unlock(&pcwd_private.io_lock);

	return r;
}

/*
 *  The ISA cards have a heartbeat bit in one of the registers, which
 *  register is card dependent.  The heartbeat bit is monitored, and if
 *  found, is considered proof that a Berkshire card has been found.
 *  The initial rate is once per second at board start up, then twice
 *  per second for normal operation.
 */
static int __devinit pcwd_isa_match(struct device *dev, unsigned int id)
{
	int base_addr = pcwd_ioports[id];
	int port0, last_port0;	/* Reg 0, in case it's REV A */
	int port1, last_port1;	/* Register 1 for REV C cards */
	int i;
	int retval;

	if (debug >= DEBUG)
		printk(KERN_DEBUG PFX "pcwd_isa_match id=%d\n",
			id);

	if (!request_region(base_addr, 4, "PCWD")) {
		printk(KERN_INFO PFX "Port 0x%04x unavailable\n", base_addr);
		return 0;
	}

	retval = 0;

	port0 = inb_p(base_addr);	/* For REV A boards */
	port1 = inb_p(base_addr + 1);	/* For REV C boards */
	if (port0 != 0xff || port1 != 0xff) {
		/* Not an 'ff' from a floating bus, so must be a card! */
		for (i = 0; i < 4; ++i) {

			msleep(500);

			last_port0 = port0;
			last_port1 = port1;

			port0 = inb_p(base_addr);
			port1 = inb_p(base_addr + 1);

			/* Has either hearbeat bit changed?  */
			if ((port0 ^ last_port0) & WD_HRTBT ||
			    (port1 ^ last_port1) & WD_REVC_HRBT) {
				retval = 1;
				break;
			}
		}
	}
	release_region(base_addr, 4);

	return retval;
}

static int __devinit pcwd_isa_probe(struct device *dev, unsigned int id)
{
	int ret;

	if (debug >= DEBUG)
		printk(KERN_DEBUG PFX "pcwd_isa_probe id=%d\n",
			id);

	cards_found++;
	if (cards_found == 1)
		printk(KERN_INFO PFX "v%s Ken Hollis (kenji@bitgate.com)\n",
								WD_VER);

	if (cards_found > 1) {
		printk(KERN_ERR PFX "This driver only supports 1 device\n");
		return -ENODEV;
	}

	if (pcwd_ioports[id] == 0x0000) {
		printk(KERN_ERR PFX "No I/O-Address for card detected\n");
		return -ENODEV;
	}
	pcwd_private.io_addr = pcwd_ioports[id];

	spin_lock_init(&pcwd_private.io_lock);

	/* Check card's revision */
	pcwd_private.revision = get_revision();

	if (!request_region(pcwd_private.io_addr,
		(pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4, "PCWD")) {
		printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
			pcwd_private.io_addr);
		ret = -EIO;
		goto error_request_region;
	}

	/* Initial variables */
	pcwd_private.supports_temp = 0;
	temp_panic = 0;
	pcwd_private.boot_status = 0x0000;

	/* get the boot_status */
	pcwd_get_status(&pcwd_private.boot_status);

	/* clear the "card caused reboot" flag */
	pcwd_clear_status();

	setup_timer(&pcwd_private.timer, pcwd_timer_ping, 0);

	/*  Disable the board  */
	pcwd_stop();

	/*  Check whether or not the card supports the temperature device */
	pcwd_check_temperature_support();

	/* Show info about the card itself */
	pcwd_show_card_info();

	/* If heartbeat = 0 then we use the heartbeat from the dip-switches */
	if (heartbeat == 0)
		heartbeat = heartbeat_tbl[(pcwd_get_option_switches() & 0x07)];

	/* Check that the heartbeat value is within it's range;
	   if not reset to the default */
	if (pcwd_set_heartbeat(heartbeat)) {
		pcwd_set_heartbeat(WATCHDOG_HEARTBEAT);
		printk(KERN_INFO PFX
		  "heartbeat value must be 2 <= heartbeat <= 7200, using %d\n",
							WATCHDOG_HEARTBEAT);
	}

	if (pcwd_private.supports_temp) {
		ret = misc_register(&temp_miscdev);
		if (ret) {
			printk(KERN_ERR PFX
			    "cannot register miscdev on minor=%d (err=%d)\n",
							TEMP_MINOR, ret);
			goto error_misc_register_temp;
		}
	}

	ret = misc_register(&pcwd_miscdev);
	if (ret) {
		printk(KERN_ERR PFX
			"cannot register miscdev on minor=%d (err=%d)\n",
					WATCHDOG_MINOR, ret);
		goto error_misc_register_watchdog;
	}

	printk(KERN_INFO PFX "initialized. heartbeat=%d sec (nowayout=%d)\n",
		heartbeat, nowayout);

	return 0;

error_misc_register_watchdog:
	if (pcwd_private.supports_temp)
		misc_deregister(&temp_miscdev);
error_misc_register_temp:
	release_region(pcwd_private.io_addr,
			(pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
error_request_region:
	pcwd_private.io_addr = 0x0000;
	cards_found--;
	return ret;
}

static int __devexit pcwd_isa_remove(struct device *dev, unsigned int id)
{
	if (debug >= DEBUG)
		printk(KERN_DEBUG PFX "pcwd_isa_remove id=%d\n",
			id);

	if (!pcwd_private.io_addr)
		return 1;

	/*  Disable the board  */
	if (!nowayout)
		pcwd_stop();

	/* Deregister */
	misc_deregister(&pcwd_miscdev);
	if (pcwd_private.supports_temp)
		misc_deregister(&temp_miscdev);
	release_region(pcwd_private.io_addr,
			(pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
	pcwd_private.io_addr = 0x0000;
	cards_found--;

	return 0;
}

static void pcwd_isa_shutdown(struct device *dev, unsigned int id)
{
	if (debug >= DEBUG)
		printk(KERN_DEBUG PFX "pcwd_isa_shutdown id=%d\n",
			id);

	pcwd_stop();
}

static struct isa_driver pcwd_isa_driver = {
	.match		= pcwd_isa_match,
	.probe		= pcwd_isa_probe,
	.remove		= __devexit_p(pcwd_isa_remove),
	.shutdown	= pcwd_isa_shutdown,
	.driver		= {
		.owner	= THIS_MODULE,
		.name	= WATCHDOG_NAME,
	},
};

static int __init pcwd_init_module(void)
{
	return isa_register_driver(&pcwd_isa_driver, PCWD_ISA_NR_CARDS);
}

static void __exit pcwd_cleanup_module(void)
{
	isa_unregister_driver(&pcwd_isa_driver);
	printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
}

module_init(pcwd_init_module);
module_exit(pcwd_cleanup_module);

MODULE_AUTHOR("Ken Hollis <kenji@bitgate.com>, Wim Van Sebroeck <wim@iguana.be>");
MODULE_DESCRIPTION("Berkshire ISA-PC Watchdog driver");
MODULE_VERSION(WATCHDOG_VERSION);
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS_MISCDEV(TEMP_MINOR);