pcwd.c 26.2 KB
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
/*
 * 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/
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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 struct miscdevice */
#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 DRIVER_VERSION WATCHDOG_DRIVER_NAME " driver, v" WATCHDOG_VERSION "\n"

/*
 * 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 unsigned long open_allowed;
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 bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 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)
		pr_debug("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)
		pr_debug("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)
		pr_debug("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)
		pr_debug("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)
		pr_info("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();
		pr_info("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();
		pr_info("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)
		pr_info("Temperature Option Detected\n");

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

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

	if (pcwd_private.boot_status == 0)
		pr_info("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 {
		pr_warn("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) {
			pr_info("Could not start watchdog\n");
			return -EIO;
		}
	}

	if (debug >= VERBOSE)
		pr_debug("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) {
			pr_info("Could not stop watchdog\n");
			return -EIO;
		}
	}

	if (debug >= VERBOSE)
		pr_debug("Watchdog stopped\n");

	return 0;
}

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

	if (debug >= DEBUG)
		pr_debug("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)
		pr_debug("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) {
				pr_info("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) {
				pr_info("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)
			pr_info("clearing watchdog trip status\n");

		control_status = inb_p(pcwd_private.io_addr + 1);

		if (debug >= DEBUG) {
			pr_debug("status was: 0x%02x\n", control_status);
			pr_debug("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) {
		pr_debug("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 const struct watchdog_info ident = {
		.options =		WDIOF_OVERHEAT |
					WDIOF_CARDRESET |
					WDIOF_KEEPALIVEPING |
					WDIOF_SETTIMEOUT |
					WDIOF_MAGICCLOSE,
		.firmware_version =	1,
		.identity =		"PCWD",
	};

	switch (cmd) {
	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);

	default:
		return -ENOTTY;
	}

	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 {
		pr_crit("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 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)
		pr_debug("pcwd_isa_match id=%d\n", id);

	if (!request_region(base_addr, 4, "PCWD")) {
		pr_info("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 pcwd_isa_probe(struct device *dev, unsigned int id)
{
	int ret;

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

	cards_found++;
	if (cards_found == 1)
		pr_info("v%s Ken Hollis (kenji@bitgate.com)\n",
							WATCHDOG_VERSION);

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

	if (pcwd_ioports[id] == 0x0000) {
		pr_err("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")) {
		pr_err("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);
		pr_info("heartbeat value must be 2 <= heartbeat <= 7200, using %d\n",
			WATCHDOG_HEARTBEAT);
	}

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

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

	pr_info("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 pcwd_isa_remove(struct device *dev, unsigned int id)
{
	if (debug >= DEBUG)
		pr_debug("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)
		pr_debug("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		= 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);
	pr_info("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");