xref: /openbmc/linux/drivers/watchdog/pcwd.c (revision 30e88d01)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * PC Watchdog Driver
4  * by Ken Hollis (khollis@bitgate.com)
5  *
6  * Permission granted from Simon Machell (smachell@berkprod.com)
7  * Written for the Linux Kernel, and GPLed by Ken Hollis
8  *
9  * 960107	Added request_region routines, modulized the whole thing.
10  * 960108	Fixed end-of-file pointer (Thanks to Dan Hollis), added
11  *		WD_TIMEOUT define.
12  * 960216	Added eof marker on the file, and changed verbose messages.
13  * 960716	Made functional and cosmetic changes to the source for
14  *		inclusion in Linux 2.0.x kernels, thanks to Alan Cox.
15  * 960717	Removed read/seek routines, replaced with ioctl.  Also, added
16  *		check_region command due to Alan's suggestion.
17  * 960821	Made changes to compile in newer 2.0.x kernels.  Added
18  *		"cold reboot sense" entry.
19  * 960825	Made a few changes to code, deleted some defines and made
20  *		typedefs to replace them.  Made heartbeat reset only available
21  *		via ioctl, and removed the write routine.
22  * 960828	Added new items for PC Watchdog Rev.C card.
23  * 960829	Changed around all of the IOCTLs, added new features,
24  *		added watchdog disable/re-enable routines.  Added firmware
25  *		version reporting.  Added read routine for temperature.
26  *		Removed some extra defines, added an autodetect Revision
27  *		routine.
28  * 961006	Revised some documentation, fixed some cosmetic bugs.  Made
29  *		drivers to panic the system if it's overheating at bootup.
30  * 961118	Changed some verbiage on some of the output, tidied up
31  *		code bits, and added compatibility to 2.1.x.
32  * 970912	Enabled board on open and disable on close.
33  * 971107	Took account of recent VFS changes (broke read).
34  * 971210	Disable board on initialisation in case board already ticking.
35  * 971222	Changed open/close for temperature handling
36  *		Michael Meskes <meskes@debian.org>.
37  * 980112	Used minor numbers from include/linux/miscdevice.h
38  * 990403	Clear reset status after reading control status register in
39  *		pcwd_showprevstate(). [Marc Boucher <marc@mbsi.ca>]
40  * 990605	Made changes to code to support Firmware 1.22a, added
41  *		fairly useless proc entry.
42  * 990610	removed said useless proc code for the merge <alan>
43  * 000403	Removed last traces of proc code. <davej>
44  * 011214	Added nowayout module option to override
45  *		CONFIG_WATCHDOG_NOWAYOUT <Matt_Domsch@dell.com>
46  *		Added timeout module option to override default
47  */
48 
49 /*
50  *	A bells and whistles driver is available from http://www.pcwd.de/
51  *	More info available at http://www.berkprod.com/ or
52  *	http://www.pcwatchdog.com/
53  */
54 
55 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
56 
57 #include <linux/module.h>	/* For module specific items */
58 #include <linux/moduleparam.h>	/* For new moduleparam's */
59 #include <linux/types.h>	/* For standard types (like size_t) */
60 #include <linux/errno.h>	/* For the -ENODEV/... values */
61 #include <linux/kernel.h>	/* For printk/panic/... */
62 #include <linux/delay.h>	/* For mdelay function */
63 #include <linux/timer.h>	/* For timer related operations */
64 #include <linux/jiffies.h>	/* For jiffies stuff */
65 #include <linux/miscdevice.h>	/* For struct miscdevice */
66 #include <linux/watchdog.h>	/* For the watchdog specific items */
67 #include <linux/reboot.h>	/* For kernel_power_off() */
68 #include <linux/init.h>		/* For __init/__exit/... */
69 #include <linux/fs.h>		/* For file operations */
70 #include <linux/isa.h>		/* For isa devices */
71 #include <linux/ioport.h>	/* For io-port access */
72 #include <linux/spinlock.h>	/* For spin_lock/spin_unlock/... */
73 #include <linux/uaccess.h>	/* For copy_to_user/put_user/... */
74 #include <linux/io.h>		/* For inb/outb/... */
75 
76 /* Module and version information */
77 #define WATCHDOG_VERSION "1.20"
78 #define WATCHDOG_DATE "18 Feb 2007"
79 #define WATCHDOG_DRIVER_NAME "ISA-PC Watchdog"
80 #define WATCHDOG_NAME "pcwd"
81 #define DRIVER_VERSION WATCHDOG_DRIVER_NAME " driver, v" WATCHDOG_VERSION "\n"
82 
83 /*
84  * It should be noted that PCWD_REVISION_B was removed because A and B
85  * are essentially the same types of card, with the exception that B
86  * has temperature reporting.  Since I didn't receive a Rev.B card,
87  * the Rev.B card is not supported.  (It's a good thing too, as they
88  * are no longer in production.)
89  */
90 #define	PCWD_REVISION_A		1
91 #define	PCWD_REVISION_C		2
92 
93 /*
94  * These are the auto-probe addresses available.
95  *
96  * Revision A only uses ports 0x270 and 0x370.  Revision C introduced 0x350.
97  * Revision A has an address range of 2 addresses, while Revision C has 4.
98  */
99 #define PCWD_ISA_NR_CARDS	3
100 static int pcwd_ioports[] = { 0x270, 0x350, 0x370, 0x000 };
101 
102 /*
103  * These are the defines that describe the control status bits for the
104  * PCI-PC Watchdog card.
105 */
106 /* Port 1 : Control Status #1 for the PC Watchdog card, revision A. */
107 #define WD_WDRST		0x01	/* Previously reset state */
108 #define WD_T110			0x02	/* Temperature overheat sense */
109 #define WD_HRTBT		0x04	/* Heartbeat sense */
110 #define WD_RLY2			0x08	/* External relay triggered */
111 #define WD_SRLY2		0x80	/* Software external relay triggered */
112 /* Port 1 : Control Status #1 for the PC Watchdog card, revision C. */
113 #define WD_REVC_WTRP		0x01	/* Watchdog Trip status */
114 #define WD_REVC_HRBT		0x02	/* Watchdog Heartbeat */
115 #define WD_REVC_TTRP		0x04	/* Temperature Trip status */
116 #define WD_REVC_RL2A		0x08	/* Relay 2 activated by
117 							on-board processor */
118 #define WD_REVC_RL1A		0x10	/* Relay 1 active */
119 #define WD_REVC_R2DS		0x40	/* Relay 2 disable */
120 #define WD_REVC_RLY2		0x80	/* Relay 2 activated? */
121 /* Port 2 : Control Status #2 */
122 #define WD_WDIS			0x10	/* Watchdog Disabled */
123 #define WD_ENTP			0x20	/* Watchdog Enable Temperature Trip */
124 #define WD_SSEL			0x40	/* Watchdog Switch Select
125 							(1:SW1 <-> 0:SW2) */
126 #define WD_WCMD			0x80	/* Watchdog Command Mode */
127 
128 /* max. time we give an ISA watchdog card to process a command */
129 /* 500ms for each 4 bit response (according to spec.) */
130 #define ISA_COMMAND_TIMEOUT     1000
131 
132 /* Watchdog's internal commands */
133 #define CMD_ISA_IDLE			0x00
134 #define CMD_ISA_VERSION_INTEGER		0x01
135 #define CMD_ISA_VERSION_TENTH		0x02
136 #define CMD_ISA_VERSION_HUNDRETH	0x03
137 #define CMD_ISA_VERSION_MINOR		0x04
138 #define CMD_ISA_SWITCH_SETTINGS		0x05
139 #define CMD_ISA_RESET_PC		0x06
140 #define CMD_ISA_ARM_0			0x07
141 #define CMD_ISA_ARM_30			0x08
142 #define CMD_ISA_ARM_60			0x09
143 #define CMD_ISA_DELAY_TIME_2SECS	0x0A
144 #define CMD_ISA_DELAY_TIME_4SECS	0x0B
145 #define CMD_ISA_DELAY_TIME_8SECS	0x0C
146 #define CMD_ISA_RESET_RELAYS		0x0D
147 
148 /* Watchdog's Dip Switch heartbeat values */
149 static const int heartbeat_tbl[] = {
150 	20,	/* OFF-OFF-OFF	= 20 Sec  */
151 	40,	/* OFF-OFF-ON	= 40 Sec  */
152 	60,	/* OFF-ON-OFF	=  1 Min  */
153 	300,	/* OFF-ON-ON	=  5 Min  */
154 	600,	/* ON-OFF-OFF	= 10 Min  */
155 	1800,	/* ON-OFF-ON	= 30 Min  */
156 	3600,	/* ON-ON-OFF	=  1 Hour */
157 	7200,	/* ON-ON-ON	=  2 hour */
158 };
159 
160 /*
161  * We are using an kernel timer to do the pinging of the watchdog
162  * every ~500ms. We try to set the internal heartbeat of the
163  * watchdog to 2 ms.
164  */
165 
166 #define WDT_INTERVAL (HZ/2+1)
167 
168 /* We can only use 1 card due to the /dev/watchdog restriction */
169 static int cards_found;
170 
171 /* internal variables */
172 static unsigned long open_allowed;
173 static char expect_close;
174 static int temp_panic;
175 
176 /* this is private data for each ISA-PC watchdog card */
177 static struct {
178 	char fw_ver_str[6];		/* The cards firmware version */
179 	int revision;			/* The card's revision */
180 	int supports_temp;		/* Whether or not the card has
181 						a temperature device */
182 	int command_mode;		/* Whether or not the card is in
183 						command mode */
184 	int boot_status;		/* The card's boot status */
185 	int io_addr;			/* The cards I/O address */
186 	spinlock_t io_lock;		/* the lock for io operations */
187 	struct timer_list timer;	/* The timer that pings the watchdog */
188 	unsigned long next_heartbeat;	/* the next_heartbeat for the timer */
189 } pcwd_private;
190 
191 /* module parameters */
192 #define QUIET	0	/* Default */
193 #define VERBOSE	1	/* Verbose */
194 #define DEBUG	2	/* print fancy stuff too */
195 static int debug = QUIET;
196 module_param(debug, int, 0);
197 MODULE_PARM_DESC(debug,
198 		"Debug level: 0=Quiet, 1=Verbose, 2=Debug (default=0)");
199 
200 /* default heartbeat = delay-time from dip-switches */
201 #define WATCHDOG_HEARTBEAT 0
202 static int heartbeat = WATCHDOG_HEARTBEAT;
203 module_param(heartbeat, int, 0);
204 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. "
205 	"(2 <= heartbeat <= 7200 or 0=delay-time from dip-switches, default="
206 				__MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
207 
208 static bool nowayout = WATCHDOG_NOWAYOUT;
209 module_param(nowayout, bool, 0);
210 MODULE_PARM_DESC(nowayout,
211 		"Watchdog cannot be stopped once started (default="
212 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
213 
214 /*
215  *	Internal functions
216  */
217 
send_isa_command(int cmd)218 static int send_isa_command(int cmd)
219 {
220 	int i;
221 	int control_status;
222 	int port0, last_port0;	/* Double read for stabilising */
223 
224 	if (debug >= DEBUG)
225 		pr_debug("sending following data cmd=0x%02x\n", cmd);
226 
227 	/* The WCMD bit must be 1 and the command is only 4 bits in size */
228 	control_status = (cmd & 0x0F) | WD_WCMD;
229 	outb_p(control_status, pcwd_private.io_addr + 2);
230 	udelay(ISA_COMMAND_TIMEOUT);
231 
232 	port0 = inb_p(pcwd_private.io_addr);
233 	for (i = 0; i < 25; ++i) {
234 		last_port0 = port0;
235 		port0 = inb_p(pcwd_private.io_addr);
236 
237 		if (port0 == last_port0)
238 			break;	/* Data is stable */
239 
240 		udelay(250);
241 	}
242 
243 	if (debug >= DEBUG)
244 		pr_debug("received following data for cmd=0x%02x: port0=0x%02x last_port0=0x%02x\n",
245 			 cmd, port0, last_port0);
246 
247 	return port0;
248 }
249 
set_command_mode(void)250 static int set_command_mode(void)
251 {
252 	int i, found = 0, count = 0;
253 
254 	/* Set the card into command mode */
255 	spin_lock(&pcwd_private.io_lock);
256 	while ((!found) && (count < 3)) {
257 		i = send_isa_command(CMD_ISA_IDLE);
258 
259 		if (i == 0x00)
260 			found = 1;
261 		else if (i == 0xF3) {
262 			/* Card does not like what we've done to it */
263 			outb_p(0x00, pcwd_private.io_addr + 2);
264 			udelay(1200);	/* Spec says wait 1ms */
265 			outb_p(0x00, pcwd_private.io_addr + 2);
266 			udelay(ISA_COMMAND_TIMEOUT);
267 		}
268 		count++;
269 	}
270 	spin_unlock(&pcwd_private.io_lock);
271 	pcwd_private.command_mode = found;
272 
273 	if (debug >= DEBUG)
274 		pr_debug("command_mode=%d\n", pcwd_private.command_mode);
275 
276 	return found;
277 }
278 
unset_command_mode(void)279 static void unset_command_mode(void)
280 {
281 	/* Set the card into normal mode */
282 	spin_lock(&pcwd_private.io_lock);
283 	outb_p(0x00, pcwd_private.io_addr + 2);
284 	udelay(ISA_COMMAND_TIMEOUT);
285 	spin_unlock(&pcwd_private.io_lock);
286 
287 	pcwd_private.command_mode = 0;
288 
289 	if (debug >= DEBUG)
290 		pr_debug("command_mode=%d\n", pcwd_private.command_mode);
291 }
292 
pcwd_check_temperature_support(void)293 static inline void pcwd_check_temperature_support(void)
294 {
295 	if (inb(pcwd_private.io_addr) != 0xF0)
296 		pcwd_private.supports_temp = 1;
297 }
298 
pcwd_get_firmware(void)299 static inline void pcwd_get_firmware(void)
300 {
301 	int one, ten, hund, minor;
302 
303 	strcpy(pcwd_private.fw_ver_str, "ERROR");
304 
305 	if (set_command_mode()) {
306 		one = send_isa_command(CMD_ISA_VERSION_INTEGER);
307 		ten = send_isa_command(CMD_ISA_VERSION_TENTH);
308 		hund = send_isa_command(CMD_ISA_VERSION_HUNDRETH);
309 		minor = send_isa_command(CMD_ISA_VERSION_MINOR);
310 		sprintf(pcwd_private.fw_ver_str, "%c.%c%c%c",
311 					one, ten, hund, minor);
312 	}
313 	unset_command_mode();
314 
315 	return;
316 }
317 
pcwd_get_option_switches(void)318 static inline int pcwd_get_option_switches(void)
319 {
320 	int option_switches = 0;
321 
322 	if (set_command_mode()) {
323 		/* Get switch settings */
324 		option_switches = send_isa_command(CMD_ISA_SWITCH_SETTINGS);
325 	}
326 
327 	unset_command_mode();
328 	return option_switches;
329 }
330 
pcwd_show_card_info(void)331 static void pcwd_show_card_info(void)
332 {
333 	int option_switches;
334 
335 	/* Get some extra info from the hardware (in command/debug/diag mode) */
336 	if (pcwd_private.revision == PCWD_REVISION_A)
337 		pr_info("ISA-PC Watchdog (REV.A) detected at port 0x%04x\n",
338 			pcwd_private.io_addr);
339 	else if (pcwd_private.revision == PCWD_REVISION_C) {
340 		pcwd_get_firmware();
341 		pr_info("ISA-PC Watchdog (REV.C) detected at port 0x%04x (Firmware version: %s)\n",
342 			pcwd_private.io_addr, pcwd_private.fw_ver_str);
343 		option_switches = pcwd_get_option_switches();
344 		pr_info("Option switches (0x%02x): Temperature Reset Enable=%s, Power On Delay=%s\n",
345 			option_switches,
346 			((option_switches & 0x10) ? "ON" : "OFF"),
347 			((option_switches & 0x08) ? "ON" : "OFF"));
348 
349 		/* Reprogram internal heartbeat to 2 seconds */
350 		if (set_command_mode()) {
351 			send_isa_command(CMD_ISA_DELAY_TIME_2SECS);
352 			unset_command_mode();
353 		}
354 	}
355 
356 	if (pcwd_private.supports_temp)
357 		pr_info("Temperature Option Detected\n");
358 
359 	if (pcwd_private.boot_status & WDIOF_CARDRESET)
360 		pr_info("Previous reboot was caused by the card\n");
361 
362 	if (pcwd_private.boot_status & WDIOF_OVERHEAT) {
363 		pr_emerg("Card senses a CPU Overheat. Panicking!\n");
364 		pr_emerg("CPU Overheat\n");
365 	}
366 
367 	if (pcwd_private.boot_status == 0)
368 		pr_info("No previous trip detected - Cold boot or reset\n");
369 }
370 
pcwd_timer_ping(struct timer_list * unused)371 static void pcwd_timer_ping(struct timer_list *unused)
372 {
373 	int wdrst_stat;
374 
375 	/* If we got a heartbeat pulse within the WDT_INTERVAL
376 	 * we agree to ping the WDT */
377 	if (time_before(jiffies, pcwd_private.next_heartbeat)) {
378 		/* Ping the watchdog */
379 		spin_lock(&pcwd_private.io_lock);
380 		if (pcwd_private.revision == PCWD_REVISION_A) {
381 			/*  Rev A cards are reset by setting the
382 			    WD_WDRST bit in register 1 */
383 			wdrst_stat = inb_p(pcwd_private.io_addr);
384 			wdrst_stat &= 0x0F;
385 			wdrst_stat |= WD_WDRST;
386 
387 			outb_p(wdrst_stat, pcwd_private.io_addr + 1);
388 		} else {
389 			/* Re-trigger watchdog by writing to port 0 */
390 			outb_p(0x00, pcwd_private.io_addr);
391 		}
392 
393 		/* Re-set the timer interval */
394 		mod_timer(&pcwd_private.timer, jiffies + WDT_INTERVAL);
395 
396 		spin_unlock(&pcwd_private.io_lock);
397 	} else {
398 		pr_warn("Heartbeat lost! Will not ping the watchdog\n");
399 	}
400 }
401 
pcwd_start(void)402 static int pcwd_start(void)
403 {
404 	int stat_reg;
405 
406 	pcwd_private.next_heartbeat = jiffies + (heartbeat * HZ);
407 
408 	/* Start the timer */
409 	mod_timer(&pcwd_private.timer, jiffies + WDT_INTERVAL);
410 
411 	/* Enable the port */
412 	if (pcwd_private.revision == PCWD_REVISION_C) {
413 		spin_lock(&pcwd_private.io_lock);
414 		outb_p(0x00, pcwd_private.io_addr + 3);
415 		udelay(ISA_COMMAND_TIMEOUT);
416 		stat_reg = inb_p(pcwd_private.io_addr + 2);
417 		spin_unlock(&pcwd_private.io_lock);
418 		if (stat_reg & WD_WDIS) {
419 			pr_info("Could not start watchdog\n");
420 			return -EIO;
421 		}
422 	}
423 
424 	if (debug >= VERBOSE)
425 		pr_debug("Watchdog started\n");
426 
427 	return 0;
428 }
429 
pcwd_stop(void)430 static int pcwd_stop(void)
431 {
432 	int stat_reg;
433 
434 	/* Stop the timer */
435 	del_timer(&pcwd_private.timer);
436 
437 	/*  Disable the board  */
438 	if (pcwd_private.revision == PCWD_REVISION_C) {
439 		spin_lock(&pcwd_private.io_lock);
440 		outb_p(0xA5, pcwd_private.io_addr + 3);
441 		udelay(ISA_COMMAND_TIMEOUT);
442 		outb_p(0xA5, pcwd_private.io_addr + 3);
443 		udelay(ISA_COMMAND_TIMEOUT);
444 		stat_reg = inb_p(pcwd_private.io_addr + 2);
445 		spin_unlock(&pcwd_private.io_lock);
446 		if ((stat_reg & WD_WDIS) == 0) {
447 			pr_info("Could not stop watchdog\n");
448 			return -EIO;
449 		}
450 	}
451 
452 	if (debug >= VERBOSE)
453 		pr_debug("Watchdog stopped\n");
454 
455 	return 0;
456 }
457 
pcwd_keepalive(void)458 static int pcwd_keepalive(void)
459 {
460 	/* user land ping */
461 	pcwd_private.next_heartbeat = jiffies + (heartbeat * HZ);
462 
463 	if (debug >= DEBUG)
464 		pr_debug("Watchdog keepalive signal send\n");
465 
466 	return 0;
467 }
468 
pcwd_set_heartbeat(int t)469 static int pcwd_set_heartbeat(int t)
470 {
471 	if (t < 2 || t > 7200) /* arbitrary upper limit */
472 		return -EINVAL;
473 
474 	heartbeat = t;
475 
476 	if (debug >= VERBOSE)
477 		pr_debug("New heartbeat: %d\n", heartbeat);
478 
479 	return 0;
480 }
481 
pcwd_get_status(int * status)482 static int pcwd_get_status(int *status)
483 {
484 	int control_status;
485 
486 	*status = 0;
487 	spin_lock(&pcwd_private.io_lock);
488 	if (pcwd_private.revision == PCWD_REVISION_A)
489 		/* Rev A cards return status information from
490 		 * the base register, which is used for the
491 		 * temperature in other cards. */
492 		control_status = inb(pcwd_private.io_addr);
493 	else {
494 		/* Rev C cards return card status in the base
495 		 * address + 1 register. And use different bits
496 		 * to indicate a card initiated reset, and an
497 		 * over-temperature condition. And the reboot
498 		 * status can be reset. */
499 		control_status = inb(pcwd_private.io_addr + 1);
500 	}
501 	spin_unlock(&pcwd_private.io_lock);
502 
503 	if (pcwd_private.revision == PCWD_REVISION_A) {
504 		if (control_status & WD_WDRST)
505 			*status |= WDIOF_CARDRESET;
506 
507 		if (control_status & WD_T110) {
508 			*status |= WDIOF_OVERHEAT;
509 			if (temp_panic) {
510 				pr_info("Temperature overheat trip!\n");
511 				kernel_power_off();
512 			}
513 		}
514 	} else {
515 		if (control_status & WD_REVC_WTRP)
516 			*status |= WDIOF_CARDRESET;
517 
518 		if (control_status & WD_REVC_TTRP) {
519 			*status |= WDIOF_OVERHEAT;
520 			if (temp_panic) {
521 				pr_info("Temperature overheat trip!\n");
522 				kernel_power_off();
523 			}
524 		}
525 	}
526 
527 	return 0;
528 }
529 
pcwd_clear_status(void)530 static int pcwd_clear_status(void)
531 {
532 	int control_status;
533 
534 	if (pcwd_private.revision == PCWD_REVISION_C) {
535 		spin_lock(&pcwd_private.io_lock);
536 
537 		if (debug >= VERBOSE)
538 			pr_info("clearing watchdog trip status\n");
539 
540 		control_status = inb_p(pcwd_private.io_addr + 1);
541 
542 		if (debug >= DEBUG) {
543 			pr_debug("status was: 0x%02x\n", control_status);
544 			pr_debug("sending: 0x%02x\n",
545 				 (control_status & WD_REVC_R2DS));
546 		}
547 
548 		/* clear reset status & Keep Relay 2 disable state as it is */
549 		outb_p((control_status & WD_REVC_R2DS),
550 						pcwd_private.io_addr + 1);
551 
552 		spin_unlock(&pcwd_private.io_lock);
553 	}
554 	return 0;
555 }
556 
pcwd_get_temperature(int * temperature)557 static int pcwd_get_temperature(int *temperature)
558 {
559 	/* check that port 0 gives temperature info and no command results */
560 	if (pcwd_private.command_mode)
561 		return -1;
562 
563 	*temperature = 0;
564 	if (!pcwd_private.supports_temp)
565 		return -ENODEV;
566 
567 	/*
568 	 * Convert celsius to fahrenheit, since this was
569 	 * the decided 'standard' for this return value.
570 	 */
571 	spin_lock(&pcwd_private.io_lock);
572 	*temperature = ((inb(pcwd_private.io_addr)) * 9 / 5) + 32;
573 	spin_unlock(&pcwd_private.io_lock);
574 
575 	if (debug >= DEBUG) {
576 		pr_debug("temperature is: %d F\n", *temperature);
577 	}
578 
579 	return 0;
580 }
581 
582 /*
583  *	/dev/watchdog handling
584  */
585 
pcwd_ioctl(struct file * file,unsigned int cmd,unsigned long arg)586 static long pcwd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
587 {
588 	int rv;
589 	int status;
590 	int temperature;
591 	int new_heartbeat;
592 	int __user *argp = (int __user *)arg;
593 	static const struct watchdog_info ident = {
594 		.options =		WDIOF_OVERHEAT |
595 					WDIOF_CARDRESET |
596 					WDIOF_KEEPALIVEPING |
597 					WDIOF_SETTIMEOUT |
598 					WDIOF_MAGICCLOSE,
599 		.firmware_version =	1,
600 		.identity =		"PCWD",
601 	};
602 
603 	switch (cmd) {
604 	case WDIOC_GETSUPPORT:
605 		if (copy_to_user(argp, &ident, sizeof(ident)))
606 			return -EFAULT;
607 		return 0;
608 
609 	case WDIOC_GETSTATUS:
610 		pcwd_get_status(&status);
611 		return put_user(status, argp);
612 
613 	case WDIOC_GETBOOTSTATUS:
614 		return put_user(pcwd_private.boot_status, argp);
615 
616 	case WDIOC_GETTEMP:
617 		if (pcwd_get_temperature(&temperature))
618 			return -EFAULT;
619 
620 		return put_user(temperature, argp);
621 
622 	case WDIOC_SETOPTIONS:
623 		if (pcwd_private.revision == PCWD_REVISION_C) {
624 			if (get_user(rv, argp))
625 				return -EFAULT;
626 
627 			if (rv & WDIOS_DISABLECARD) {
628 				status = pcwd_stop();
629 				if (status < 0)
630 					return status;
631 			}
632 			if (rv & WDIOS_ENABLECARD) {
633 				status = pcwd_start();
634 				if (status < 0)
635 					return status;
636 			}
637 			if (rv & WDIOS_TEMPPANIC)
638 				temp_panic = 1;
639 		}
640 		return -EINVAL;
641 
642 	case WDIOC_KEEPALIVE:
643 		pcwd_keepalive();
644 		return 0;
645 
646 	case WDIOC_SETTIMEOUT:
647 		if (get_user(new_heartbeat, argp))
648 			return -EFAULT;
649 
650 		if (pcwd_set_heartbeat(new_heartbeat))
651 			return -EINVAL;
652 
653 		pcwd_keepalive();
654 		fallthrough;
655 
656 	case WDIOC_GETTIMEOUT:
657 		return put_user(heartbeat, argp);
658 
659 	default:
660 		return -ENOTTY;
661 	}
662 
663 	return 0;
664 }
665 
pcwd_write(struct file * file,const char __user * buf,size_t len,loff_t * ppos)666 static ssize_t pcwd_write(struct file *file, const char __user *buf, size_t len,
667 			  loff_t *ppos)
668 {
669 	if (len) {
670 		if (!nowayout) {
671 			size_t i;
672 
673 			/* In case it was set long ago */
674 			expect_close = 0;
675 
676 			for (i = 0; i != len; i++) {
677 				char c;
678 
679 				if (get_user(c, buf + i))
680 					return -EFAULT;
681 				if (c == 'V')
682 					expect_close = 42;
683 			}
684 		}
685 		pcwd_keepalive();
686 	}
687 	return len;
688 }
689 
pcwd_open(struct inode * inode,struct file * file)690 static int pcwd_open(struct inode *inode, struct file *file)
691 {
692 	if (test_and_set_bit(0, &open_allowed))
693 		return -EBUSY;
694 	if (nowayout)
695 		__module_get(THIS_MODULE);
696 	/* Activate */
697 	pcwd_start();
698 	pcwd_keepalive();
699 	return stream_open(inode, file);
700 }
701 
pcwd_close(struct inode * inode,struct file * file)702 static int pcwd_close(struct inode *inode, struct file *file)
703 {
704 	if (expect_close == 42)
705 		pcwd_stop();
706 	else {
707 		pr_crit("Unexpected close, not stopping watchdog!\n");
708 		pcwd_keepalive();
709 	}
710 	expect_close = 0;
711 	clear_bit(0, &open_allowed);
712 	return 0;
713 }
714 
715 /*
716  *	/dev/temperature handling
717  */
718 
pcwd_temp_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)719 static ssize_t pcwd_temp_read(struct file *file, char __user *buf, size_t count,
720 			 loff_t *ppos)
721 {
722 	int temperature;
723 
724 	if (pcwd_get_temperature(&temperature))
725 		return -EFAULT;
726 
727 	if (copy_to_user(buf, &temperature, 1))
728 		return -EFAULT;
729 
730 	return 1;
731 }
732 
pcwd_temp_open(struct inode * inode,struct file * file)733 static int pcwd_temp_open(struct inode *inode, struct file *file)
734 {
735 	if (!pcwd_private.supports_temp)
736 		return -ENODEV;
737 
738 	return stream_open(inode, file);
739 }
740 
pcwd_temp_close(struct inode * inode,struct file * file)741 static int pcwd_temp_close(struct inode *inode, struct file *file)
742 {
743 	return 0;
744 }
745 
746 /*
747  *	Kernel Interfaces
748  */
749 
750 static const struct file_operations pcwd_fops = {
751 	.owner		= THIS_MODULE,
752 	.llseek		= no_llseek,
753 	.write		= pcwd_write,
754 	.unlocked_ioctl	= pcwd_ioctl,
755 	.compat_ioctl	= compat_ptr_ioctl,
756 	.open		= pcwd_open,
757 	.release	= pcwd_close,
758 };
759 
760 static struct miscdevice pcwd_miscdev = {
761 	.minor =	WATCHDOG_MINOR,
762 	.name =		"watchdog",
763 	.fops =		&pcwd_fops,
764 };
765 
766 static const struct file_operations pcwd_temp_fops = {
767 	.owner		= THIS_MODULE,
768 	.llseek		= no_llseek,
769 	.read		= pcwd_temp_read,
770 	.open		= pcwd_temp_open,
771 	.release	= pcwd_temp_close,
772 };
773 
774 static struct miscdevice temp_miscdev = {
775 	.minor =	TEMP_MINOR,
776 	.name =		"temperature",
777 	.fops =		&pcwd_temp_fops,
778 };
779 
780 /*
781  *	Init & exit routines
782  */
783 
get_revision(void)784 static inline int get_revision(void)
785 {
786 	int r = PCWD_REVISION_C;
787 
788 	spin_lock(&pcwd_private.io_lock);
789 	/* REV A cards use only 2 io ports; test
790 	 * presumes a floating bus reads as 0xff. */
791 	if ((inb(pcwd_private.io_addr + 2) == 0xFF) ||
792 	    (inb(pcwd_private.io_addr + 3) == 0xFF))
793 		r = PCWD_REVISION_A;
794 	spin_unlock(&pcwd_private.io_lock);
795 
796 	return r;
797 }
798 
799 /*
800  *  The ISA cards have a heartbeat bit in one of the registers, which
801  *  register is card dependent.  The heartbeat bit is monitored, and if
802  *  found, is considered proof that a Berkshire card has been found.
803  *  The initial rate is once per second at board start up, then twice
804  *  per second for normal operation.
805  */
pcwd_isa_match(struct device * dev,unsigned int id)806 static int pcwd_isa_match(struct device *dev, unsigned int id)
807 {
808 	int base_addr = pcwd_ioports[id];
809 	int port0, last_port0;	/* Reg 0, in case it's REV A */
810 	int port1, last_port1;	/* Register 1 for REV C cards */
811 	int i;
812 	int retval;
813 
814 	if (debug >= DEBUG)
815 		pr_debug("pcwd_isa_match id=%d\n", id);
816 
817 	if (!request_region(base_addr, 4, "PCWD")) {
818 		pr_info("Port 0x%04x unavailable\n", base_addr);
819 		return 0;
820 	}
821 
822 	retval = 0;
823 
824 	port0 = inb_p(base_addr);	/* For REV A boards */
825 	port1 = inb_p(base_addr + 1);	/* For REV C boards */
826 	if (port0 != 0xff || port1 != 0xff) {
827 		/* Not an 'ff' from a floating bus, so must be a card! */
828 		for (i = 0; i < 4; ++i) {
829 
830 			msleep(500);
831 
832 			last_port0 = port0;
833 			last_port1 = port1;
834 
835 			port0 = inb_p(base_addr);
836 			port1 = inb_p(base_addr + 1);
837 
838 			/* Has either hearbeat bit changed?  */
839 			if ((port0 ^ last_port0) & WD_HRTBT ||
840 			    (port1 ^ last_port1) & WD_REVC_HRBT) {
841 				retval = 1;
842 				break;
843 			}
844 		}
845 	}
846 	release_region(base_addr, 4);
847 
848 	return retval;
849 }
850 
pcwd_isa_probe(struct device * dev,unsigned int id)851 static int pcwd_isa_probe(struct device *dev, unsigned int id)
852 {
853 	int ret;
854 
855 	if (debug >= DEBUG)
856 		pr_debug("pcwd_isa_probe id=%d\n", id);
857 
858 	cards_found++;
859 	if (cards_found == 1)
860 		pr_info("v%s Ken Hollis (kenji@bitgate.com)\n",
861 							WATCHDOG_VERSION);
862 
863 	if (cards_found > 1) {
864 		pr_err("This driver only supports 1 device\n");
865 		return -ENODEV;
866 	}
867 
868 	if (pcwd_ioports[id] == 0x0000) {
869 		pr_err("No I/O-Address for card detected\n");
870 		return -ENODEV;
871 	}
872 	pcwd_private.io_addr = pcwd_ioports[id];
873 
874 	spin_lock_init(&pcwd_private.io_lock);
875 
876 	/* Check card's revision */
877 	pcwd_private.revision = get_revision();
878 
879 	if (!request_region(pcwd_private.io_addr,
880 		(pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4, "PCWD")) {
881 		pr_err("I/O address 0x%04x already in use\n",
882 		       pcwd_private.io_addr);
883 		ret = -EIO;
884 		goto error_request_region;
885 	}
886 
887 	/* Initial variables */
888 	pcwd_private.supports_temp = 0;
889 	temp_panic = 0;
890 	pcwd_private.boot_status = 0x0000;
891 
892 	/* get the boot_status */
893 	pcwd_get_status(&pcwd_private.boot_status);
894 
895 	/* clear the "card caused reboot" flag */
896 	pcwd_clear_status();
897 
898 	timer_setup(&pcwd_private.timer, pcwd_timer_ping, 0);
899 
900 	/*  Disable the board  */
901 	pcwd_stop();
902 
903 	/*  Check whether or not the card supports the temperature device */
904 	pcwd_check_temperature_support();
905 
906 	/* Show info about the card itself */
907 	pcwd_show_card_info();
908 
909 	/* If heartbeat = 0 then we use the heartbeat from the dip-switches */
910 	if (heartbeat == 0)
911 		heartbeat = heartbeat_tbl[(pcwd_get_option_switches() & 0x07)];
912 
913 	/* Check that the heartbeat value is within it's range;
914 	   if not reset to the default */
915 	if (pcwd_set_heartbeat(heartbeat)) {
916 		pcwd_set_heartbeat(WATCHDOG_HEARTBEAT);
917 		pr_info("heartbeat value must be 2 <= heartbeat <= 7200, using %d\n",
918 			WATCHDOG_HEARTBEAT);
919 	}
920 
921 	if (pcwd_private.supports_temp) {
922 		ret = misc_register(&temp_miscdev);
923 		if (ret) {
924 			pr_err("cannot register miscdev on minor=%d (err=%d)\n",
925 			       TEMP_MINOR, ret);
926 			goto error_misc_register_temp;
927 		}
928 	}
929 
930 	ret = misc_register(&pcwd_miscdev);
931 	if (ret) {
932 		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
933 		       WATCHDOG_MINOR, ret);
934 		goto error_misc_register_watchdog;
935 	}
936 
937 	pr_info("initialized. heartbeat=%d sec (nowayout=%d)\n",
938 		heartbeat, nowayout);
939 
940 	return 0;
941 
942 error_misc_register_watchdog:
943 	if (pcwd_private.supports_temp)
944 		misc_deregister(&temp_miscdev);
945 error_misc_register_temp:
946 	release_region(pcwd_private.io_addr,
947 			(pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
948 error_request_region:
949 	pcwd_private.io_addr = 0x0000;
950 	cards_found--;
951 	return ret;
952 }
953 
pcwd_isa_remove(struct device * dev,unsigned int id)954 static void pcwd_isa_remove(struct device *dev, unsigned int id)
955 {
956 	if (debug >= DEBUG)
957 		pr_debug("pcwd_isa_remove id=%d\n", id);
958 
959 	/*  Disable the board  */
960 	if (!nowayout)
961 		pcwd_stop();
962 
963 	/* Deregister */
964 	misc_deregister(&pcwd_miscdev);
965 	if (pcwd_private.supports_temp)
966 		misc_deregister(&temp_miscdev);
967 	release_region(pcwd_private.io_addr,
968 			(pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
969 	pcwd_private.io_addr = 0x0000;
970 	cards_found--;
971 }
972 
pcwd_isa_shutdown(struct device * dev,unsigned int id)973 static void pcwd_isa_shutdown(struct device *dev, unsigned int id)
974 {
975 	if (debug >= DEBUG)
976 		pr_debug("pcwd_isa_shutdown id=%d\n", id);
977 
978 	pcwd_stop();
979 }
980 
981 static struct isa_driver pcwd_isa_driver = {
982 	.match		= pcwd_isa_match,
983 	.probe		= pcwd_isa_probe,
984 	.remove		= pcwd_isa_remove,
985 	.shutdown	= pcwd_isa_shutdown,
986 	.driver		= {
987 		.owner	= THIS_MODULE,
988 		.name	= WATCHDOG_NAME,
989 	},
990 };
991 
992 module_isa_driver(pcwd_isa_driver, PCWD_ISA_NR_CARDS);
993 
994 MODULE_AUTHOR("Ken Hollis <kenji@bitgate.com>, "
995 		"Wim Van Sebroeck <wim@iguana.be>");
996 MODULE_DESCRIPTION("Berkshire ISA-PC Watchdog driver");
997 MODULE_VERSION(WATCHDOG_VERSION);
998 MODULE_LICENSE("GPL");
999