1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Industrial Computer Source WDT501 driver
4 *
5 * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
6 * All Rights Reserved.
7 *
8 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
9 * warranty for any of this software. This material is provided
10 * "AS-IS" and at no charge.
11 *
12 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
13 *
14 * Release 0.10.
15 *
16 * Fixes
17 * Dave Gregorich : Modularisation and minor bugs
18 * Alan Cox : Added the watchdog ioctl() stuff
19 * Alan Cox : Fixed the reboot problem (as noted by
20 * Matt Crocker).
21 * Alan Cox : Added wdt= boot option
22 * Alan Cox : Cleaned up copy/user stuff
23 * Tim Hockin : Added insmod parameters, comment
24 * cleanup, parameterized timeout
25 * Tigran Aivazian : Restructured wdt_init() to handle
26 * failures
27 * Joel Becker : Added WDIOC_GET/SETTIMEOUT
28 * Matt Domsch : Added nowayout module option
29 */
30
31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
32
33 #include <linux/interrupt.h>
34 #include <linux/module.h>
35 #include <linux/moduleparam.h>
36 #include <linux/types.h>
37 #include <linux/miscdevice.h>
38 #include <linux/watchdog.h>
39 #include <linux/fs.h>
40 #include <linux/ioport.h>
41 #include <linux/notifier.h>
42 #include <linux/reboot.h>
43 #include <linux/init.h>
44 #include <linux/io.h>
45 #include <linux/uaccess.h>
46
47 #include "wd501p.h"
48
49 static unsigned long wdt_is_open;
50 static char expect_close;
51
52 /*
53 * Module parameters
54 */
55
56 #define WD_TIMO 60 /* Default heartbeat = 60 seconds */
57
58 static int heartbeat = WD_TIMO;
59 static int wd_heartbeat;
60 module_param(heartbeat, int, 0);
61 MODULE_PARM_DESC(heartbeat,
62 "Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default="
63 __MODULE_STRING(WD_TIMO) ")");
64
65 static bool nowayout = WATCHDOG_NOWAYOUT;
66 module_param(nowayout, bool, 0);
67 MODULE_PARM_DESC(nowayout,
68 "Watchdog cannot be stopped once started (default="
69 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
70
71 /* You must set these - there is no sane way to probe for this board. */
72 static int io = 0x240;
73 static int irq = 11;
74
75 static DEFINE_SPINLOCK(wdt_lock);
76
77 module_param_hw(io, int, ioport, 0);
78 MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
79 module_param_hw(irq, int, irq, 0);
80 MODULE_PARM_DESC(irq, "WDT irq (default=11)");
81
82 /* Support for the Fan Tachometer on the WDT501-P */
83 static int tachometer;
84 module_param(tachometer, int, 0);
85 MODULE_PARM_DESC(tachometer,
86 "WDT501-P Fan Tachometer support (0=disable, default=0)");
87
88 static int type = 500;
89 module_param(type, int, 0);
90 MODULE_PARM_DESC(type,
91 "WDT501-P Card type (500 or 501, default=500)");
92
93 /*
94 * Programming support
95 */
96
wdt_ctr_mode(int ctr,int mode)97 static void wdt_ctr_mode(int ctr, int mode)
98 {
99 ctr <<= 6;
100 ctr |= 0x30;
101 ctr |= (mode << 1);
102 outb_p(ctr, WDT_CR);
103 }
104
wdt_ctr_load(int ctr,int val)105 static void wdt_ctr_load(int ctr, int val)
106 {
107 outb_p(val&0xFF, WDT_COUNT0+ctr);
108 outb_p(val>>8, WDT_COUNT0+ctr);
109 }
110
111 /**
112 * wdt_start:
113 *
114 * Start the watchdog driver.
115 */
116
wdt_start(void)117 static int wdt_start(void)
118 {
119 unsigned long flags;
120 spin_lock_irqsave(&wdt_lock, flags);
121 inb_p(WDT_DC); /* Disable watchdog */
122 wdt_ctr_mode(0, 3); /* Program CTR0 for Mode 3:
123 Square Wave Generator */
124 wdt_ctr_mode(1, 2); /* Program CTR1 for Mode 2:
125 Rate Generator */
126 wdt_ctr_mode(2, 0); /* Program CTR2 for Mode 0:
127 Pulse on Terminal Count */
128 wdt_ctr_load(0, 8948); /* Count at 100Hz */
129 wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */
130 wdt_ctr_load(2, 65535); /* Length of reset pulse */
131 outb_p(0, WDT_DC); /* Enable watchdog */
132 spin_unlock_irqrestore(&wdt_lock, flags);
133 return 0;
134 }
135
136 /**
137 * wdt_stop:
138 *
139 * Stop the watchdog driver.
140 */
141
wdt_stop(void)142 static int wdt_stop(void)
143 {
144 unsigned long flags;
145 spin_lock_irqsave(&wdt_lock, flags);
146 /* Turn the card off */
147 inb_p(WDT_DC); /* Disable watchdog */
148 wdt_ctr_load(2, 0); /* 0 length reset pulses now */
149 spin_unlock_irqrestore(&wdt_lock, flags);
150 return 0;
151 }
152
153 /**
154 * wdt_ping:
155 *
156 * Reload counter one with the watchdog heartbeat. We don't bother
157 * reloading the cascade counter.
158 */
159
wdt_ping(void)160 static void wdt_ping(void)
161 {
162 unsigned long flags;
163 spin_lock_irqsave(&wdt_lock, flags);
164 /* Write a watchdog value */
165 inb_p(WDT_DC); /* Disable watchdog */
166 wdt_ctr_mode(1, 2); /* Re-Program CTR1 for Mode 2:
167 Rate Generator */
168 wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */
169 outb_p(0, WDT_DC); /* Enable watchdog */
170 spin_unlock_irqrestore(&wdt_lock, flags);
171 }
172
173 /**
174 * wdt_set_heartbeat:
175 * @t: the new heartbeat value that needs to be set.
176 *
177 * Set a new heartbeat value for the watchdog device. If the heartbeat
178 * value is incorrect we keep the old value and return -EINVAL. If
179 * successful we return 0.
180 */
181
wdt_set_heartbeat(int t)182 static int wdt_set_heartbeat(int t)
183 {
184 if (t < 1 || t > 65535)
185 return -EINVAL;
186
187 heartbeat = t;
188 wd_heartbeat = t * 100;
189 return 0;
190 }
191
192 /**
193 * wdt_get_status:
194 *
195 * Extract the status information from a WDT watchdog device. There are
196 * several board variants so we have to know which bits are valid. Some
197 * bits default to one and some to zero in order to be maximally painful.
198 *
199 * we then map the bits onto the status ioctl flags.
200 */
201
wdt_get_status(void)202 static int wdt_get_status(void)
203 {
204 unsigned char new_status;
205 int status = 0;
206 unsigned long flags;
207
208 spin_lock_irqsave(&wdt_lock, flags);
209 new_status = inb_p(WDT_SR);
210 spin_unlock_irqrestore(&wdt_lock, flags);
211
212 if (new_status & WDC_SR_ISOI0)
213 status |= WDIOF_EXTERN1;
214 if (new_status & WDC_SR_ISII1)
215 status |= WDIOF_EXTERN2;
216 if (type == 501) {
217 if (!(new_status & WDC_SR_TGOOD))
218 status |= WDIOF_OVERHEAT;
219 if (!(new_status & WDC_SR_PSUOVER))
220 status |= WDIOF_POWEROVER;
221 if (!(new_status & WDC_SR_PSUUNDR))
222 status |= WDIOF_POWERUNDER;
223 if (tachometer) {
224 if (!(new_status & WDC_SR_FANGOOD))
225 status |= WDIOF_FANFAULT;
226 }
227 }
228 return status;
229 }
230
231 /**
232 * wdt_get_temperature:
233 *
234 * Reports the temperature in degrees Fahrenheit. The API is in
235 * farenheit. It was designed by an imperial measurement luddite.
236 */
237
wdt_get_temperature(void)238 static int wdt_get_temperature(void)
239 {
240 unsigned short c;
241 unsigned long flags;
242
243 spin_lock_irqsave(&wdt_lock, flags);
244 c = inb_p(WDT_RT);
245 spin_unlock_irqrestore(&wdt_lock, flags);
246 return (c * 11 / 15) + 7;
247 }
248
wdt_decode_501(int status)249 static void wdt_decode_501(int status)
250 {
251 if (!(status & WDC_SR_TGOOD))
252 pr_crit("Overheat alarm (%d)\n", inb_p(WDT_RT));
253 if (!(status & WDC_SR_PSUOVER))
254 pr_crit("PSU over voltage\n");
255 if (!(status & WDC_SR_PSUUNDR))
256 pr_crit("PSU under voltage\n");
257 }
258
259 /**
260 * wdt_interrupt:
261 * @irq: Interrupt number
262 * @dev_id: Unused as we don't allow multiple devices.
263 *
264 * Handle an interrupt from the board. These are raised when the status
265 * map changes in what the board considers an interesting way. That means
266 * a failure condition occurring.
267 */
268
wdt_interrupt(int irq,void * dev_id)269 static irqreturn_t wdt_interrupt(int irq, void *dev_id)
270 {
271 /*
272 * Read the status register see what is up and
273 * then printk it.
274 */
275 unsigned char status;
276
277 spin_lock(&wdt_lock);
278 status = inb_p(WDT_SR);
279
280 pr_crit("WDT status %d\n", status);
281
282 if (type == 501) {
283 wdt_decode_501(status);
284 if (tachometer) {
285 if (!(status & WDC_SR_FANGOOD))
286 pr_crit("Possible fan fault\n");
287 }
288 }
289 if (!(status & WDC_SR_WCCR)) {
290 #ifdef SOFTWARE_REBOOT
291 #ifdef ONLY_TESTING
292 pr_crit("Would Reboot\n");
293 #else
294 pr_crit("Initiating system reboot\n");
295 emergency_restart();
296 #endif
297 #else
298 pr_crit("Reset in 5ms\n");
299 #endif
300 }
301 spin_unlock(&wdt_lock);
302 return IRQ_HANDLED;
303 }
304
305
306 /**
307 * wdt_write:
308 * @file: file handle to the watchdog
309 * @buf: buffer to write (unused as data does not matter here
310 * @count: count of bytes
311 * @ppos: pointer to the position to write. No seeks allowed
312 *
313 * A write to a watchdog device is defined as a keepalive signal. Any
314 * write of data will do, as we we don't define content meaning.
315 */
316
wdt_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)317 static ssize_t wdt_write(struct file *file, const char __user *buf,
318 size_t count, loff_t *ppos)
319 {
320 if (count) {
321 if (!nowayout) {
322 size_t i;
323
324 /* In case it was set long ago */
325 expect_close = 0;
326
327 for (i = 0; i != count; i++) {
328 char c;
329 if (get_user(c, buf + i))
330 return -EFAULT;
331 if (c == 'V')
332 expect_close = 42;
333 }
334 }
335 wdt_ping();
336 }
337 return count;
338 }
339
340 /**
341 * wdt_ioctl:
342 * @file: file handle to the device
343 * @cmd: watchdog command
344 * @arg: argument pointer
345 *
346 * The watchdog API defines a common set of functions for all watchdogs
347 * according to their available features. We only actually usefully support
348 * querying capabilities and current status.
349 */
350
wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)351 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
352 {
353 void __user *argp = (void __user *)arg;
354 int __user *p = argp;
355 int new_heartbeat;
356 int status;
357
358 struct watchdog_info ident = {
359 .options = WDIOF_SETTIMEOUT|
360 WDIOF_MAGICCLOSE|
361 WDIOF_KEEPALIVEPING,
362 .firmware_version = 1,
363 .identity = "WDT500/501",
364 };
365
366 /* Add options according to the card we have */
367 ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);
368 if (type == 501) {
369 ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|
370 WDIOF_POWEROVER);
371 if (tachometer)
372 ident.options |= WDIOF_FANFAULT;
373 }
374
375 switch (cmd) {
376 case WDIOC_GETSUPPORT:
377 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
378 case WDIOC_GETSTATUS:
379 status = wdt_get_status();
380 return put_user(status, p);
381 case WDIOC_GETBOOTSTATUS:
382 return put_user(0, p);
383 case WDIOC_KEEPALIVE:
384 wdt_ping();
385 return 0;
386 case WDIOC_SETTIMEOUT:
387 if (get_user(new_heartbeat, p))
388 return -EFAULT;
389 if (wdt_set_heartbeat(new_heartbeat))
390 return -EINVAL;
391 wdt_ping();
392 fallthrough;
393 case WDIOC_GETTIMEOUT:
394 return put_user(heartbeat, p);
395 default:
396 return -ENOTTY;
397 }
398 }
399
400 /**
401 * wdt_open:
402 * @inode: inode of device
403 * @file: file handle to device
404 *
405 * The watchdog device has been opened. The watchdog device is single
406 * open and on opening we load the counters. Counter zero is a 100Hz
407 * cascade, into counter 1 which downcounts to reboot. When the counter
408 * triggers counter 2 downcounts the length of the reset pulse which
409 * set set to be as long as possible.
410 */
411
wdt_open(struct inode * inode,struct file * file)412 static int wdt_open(struct inode *inode, struct file *file)
413 {
414 if (test_and_set_bit(0, &wdt_is_open))
415 return -EBUSY;
416 /*
417 * Activate
418 */
419 wdt_start();
420 return stream_open(inode, file);
421 }
422
423 /**
424 * wdt_release:
425 * @inode: inode to board
426 * @file: file handle to board
427 *
428 * The watchdog has a configurable API. There is a religious dispute
429 * between people who want their watchdog to be able to shut down and
430 * those who want to be sure if the watchdog manager dies the machine
431 * reboots. In the former case we disable the counters, in the latter
432 * case you have to open it again very soon.
433 */
434
wdt_release(struct inode * inode,struct file * file)435 static int wdt_release(struct inode *inode, struct file *file)
436 {
437 if (expect_close == 42) {
438 wdt_stop();
439 clear_bit(0, &wdt_is_open);
440 } else {
441 pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");
442 wdt_ping();
443 }
444 expect_close = 0;
445 return 0;
446 }
447
448 /**
449 * wdt_temp_read:
450 * @file: file handle to the watchdog board
451 * @buf: buffer to write 1 byte into
452 * @count: length of buffer
453 * @ptr: offset (no seek allowed)
454 *
455 * Temp_read reports the temperature in degrees Fahrenheit. The API is in
456 * farenheit. It was designed by an imperial measurement luddite.
457 */
458
wdt_temp_read(struct file * file,char __user * buf,size_t count,loff_t * ptr)459 static ssize_t wdt_temp_read(struct file *file, char __user *buf,
460 size_t count, loff_t *ptr)
461 {
462 int temperature = wdt_get_temperature();
463
464 if (copy_to_user(buf, &temperature, 1))
465 return -EFAULT;
466
467 return 1;
468 }
469
470 /**
471 * wdt_temp_open:
472 * @inode: inode of device
473 * @file: file handle to device
474 *
475 * The temperature device has been opened.
476 */
477
wdt_temp_open(struct inode * inode,struct file * file)478 static int wdt_temp_open(struct inode *inode, struct file *file)
479 {
480 return stream_open(inode, file);
481 }
482
483 /**
484 * wdt_temp_release:
485 * @inode: inode to board
486 * @file: file handle to board
487 *
488 * The temperature device has been closed.
489 */
490
wdt_temp_release(struct inode * inode,struct file * file)491 static int wdt_temp_release(struct inode *inode, struct file *file)
492 {
493 return 0;
494 }
495
496 /**
497 * wdt_notify_sys:
498 * @this: our notifier block
499 * @code: the event being reported
500 * @unused: unused
501 *
502 * Our notifier is called on system shutdowns. We want to turn the card
503 * off at reboot otherwise the machine will reboot again during memory
504 * test or worse yet during the following fsck. This would suck, in fact
505 * trust me - if it happens it does suck.
506 */
507
wdt_notify_sys(struct notifier_block * this,unsigned long code,void * unused)508 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
509 void *unused)
510 {
511 if (code == SYS_DOWN || code == SYS_HALT)
512 wdt_stop();
513 return NOTIFY_DONE;
514 }
515
516 /*
517 * Kernel Interfaces
518 */
519
520
521 static const struct file_operations wdt_fops = {
522 .owner = THIS_MODULE,
523 .llseek = no_llseek,
524 .write = wdt_write,
525 .unlocked_ioctl = wdt_ioctl,
526 .compat_ioctl = compat_ptr_ioctl,
527 .open = wdt_open,
528 .release = wdt_release,
529 };
530
531 static struct miscdevice wdt_miscdev = {
532 .minor = WATCHDOG_MINOR,
533 .name = "watchdog",
534 .fops = &wdt_fops,
535 };
536
537 static const struct file_operations wdt_temp_fops = {
538 .owner = THIS_MODULE,
539 .llseek = no_llseek,
540 .read = wdt_temp_read,
541 .open = wdt_temp_open,
542 .release = wdt_temp_release,
543 };
544
545 static struct miscdevice temp_miscdev = {
546 .minor = TEMP_MINOR,
547 .name = "temperature",
548 .fops = &wdt_temp_fops,
549 };
550
551 /*
552 * The WDT card needs to learn about soft shutdowns in order to
553 * turn the timebomb registers off.
554 */
555
556 static struct notifier_block wdt_notifier = {
557 .notifier_call = wdt_notify_sys,
558 };
559
560 /**
561 * wdt_exit:
562 *
563 * Unload the watchdog. You cannot do this with any file handles open.
564 * If your watchdog is set to continue ticking on close and you unload
565 * it, well it keeps ticking. We won't get the interrupt but the board
566 * will not touch PC memory so all is fine. You just have to load a new
567 * module in 60 seconds or reboot.
568 */
569
wdt_exit(void)570 static void __exit wdt_exit(void)
571 {
572 misc_deregister(&wdt_miscdev);
573 if (type == 501)
574 misc_deregister(&temp_miscdev);
575 unregister_reboot_notifier(&wdt_notifier);
576 free_irq(irq, NULL);
577 release_region(io, 8);
578 }
579
580 /**
581 * wdt_init:
582 *
583 * Set up the WDT watchdog board. All we have to do is grab the
584 * resources we require and bitch if anyone beat us to them.
585 * The open() function will actually kick the board off.
586 */
587
wdt_init(void)588 static int __init wdt_init(void)
589 {
590 int ret;
591
592 if (type != 500 && type != 501) {
593 pr_err("unknown card type '%d'\n", type);
594 return -ENODEV;
595 }
596
597 /* Check that the heartbeat value is within it's range;
598 if not reset to the default */
599 if (wdt_set_heartbeat(heartbeat)) {
600 wdt_set_heartbeat(WD_TIMO);
601 pr_info("heartbeat value must be 0 < heartbeat < 65536, using %d\n",
602 WD_TIMO);
603 }
604
605 if (!request_region(io, 8, "wdt501p")) {
606 pr_err("I/O address 0x%04x already in use\n", io);
607 ret = -EBUSY;
608 goto out;
609 }
610
611 ret = request_irq(irq, wdt_interrupt, 0, "wdt501p", NULL);
612 if (ret) {
613 pr_err("IRQ %d is not free\n", irq);
614 goto outreg;
615 }
616
617 ret = register_reboot_notifier(&wdt_notifier);
618 if (ret) {
619 pr_err("cannot register reboot notifier (err=%d)\n", ret);
620 goto outirq;
621 }
622
623 if (type == 501) {
624 ret = misc_register(&temp_miscdev);
625 if (ret) {
626 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
627 TEMP_MINOR, ret);
628 goto outrbt;
629 }
630 }
631
632 ret = misc_register(&wdt_miscdev);
633 if (ret) {
634 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
635 WATCHDOG_MINOR, ret);
636 goto outmisc;
637 }
638
639 pr_info("WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",
640 io, irq, heartbeat, nowayout);
641 if (type == 501)
642 pr_info("Fan Tachometer is %s\n",
643 tachometer ? "Enabled" : "Disabled");
644 return 0;
645
646 outmisc:
647 if (type == 501)
648 misc_deregister(&temp_miscdev);
649 outrbt:
650 unregister_reboot_notifier(&wdt_notifier);
651 outirq:
652 free_irq(irq, NULL);
653 outreg:
654 release_region(io, 8);
655 out:
656 return ret;
657 }
658
659 module_init(wdt_init);
660 module_exit(wdt_exit);
661
662 MODULE_AUTHOR("Alan Cox");
663 MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)");
664 MODULE_LICENSE("GPL");
665