2 * Industrial Computer Source WDT501 driver
4 * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
12 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
13 * warranty for any of this software. This material is provided
14 * "AS-IS" and at no charge.
16 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
21 * Dave Gregorich : Modularisation and minor bugs
22 * Alan Cox : Added the watchdog ioctl() stuff
23 * Alan Cox : Fixed the reboot problem (as noted by
25 * Alan Cox : Added wdt= boot option
26 * Alan Cox : Cleaned up copy/user stuff
27 * Tim Hockin : Added insmod parameters, comment
28 * cleanup, parameterized timeout
29 * Tigran Aivazian : Restructured wdt_init() to handle
31 * Joel Becker : Added WDIOC_GET/SETTIMEOUT
32 * Matt Domsch : Added nowayout module option
35 #include <linux/interrupt.h>
36 #include <linux/module.h>
37 #include <linux/moduleparam.h>
38 #include <linux/types.h>
39 #include <linux/miscdevice.h>
40 #include <linux/watchdog.h>
42 #include <linux/ioport.h>
43 #include <linux/notifier.h>
44 #include <linux/reboot.h>
45 #include <linux/init.h>
47 #include <linux/uaccess.h>
51 static unsigned long wdt_is_open;
52 static char expect_close;
58 #define WD_TIMO 60 /* Default heartbeat = 60 seconds */
60 static int heartbeat = WD_TIMO;
61 static int wd_heartbeat;
62 module_param(heartbeat, int, 0);
63 MODULE_PARM_DESC(heartbeat,
64 "Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default="
65 __MODULE_STRING(WD_TIMO) ")");
67 static int nowayout = WATCHDOG_NOWAYOUT;
68 module_param(nowayout, int, 0);
69 MODULE_PARM_DESC(nowayout,
70 "Watchdog cannot be stopped once started (default="
71 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
73 /* You must set these - there is no sane way to probe for this board. */
74 static int io = 0x240;
77 static DEFINE_SPINLOCK(wdt_lock);
79 module_param(io, int, 0);
80 MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
81 module_param(irq, int, 0);
82 MODULE_PARM_DESC(irq, "WDT irq (default=11)");
84 /* Support for the Fan Tachometer on the WDT501-P */
85 static int tachometer;
86 module_param(tachometer, int, 0);
87 MODULE_PARM_DESC(tachometer,
88 "WDT501-P Fan Tachometer support (0=disable, default=0)");
90 static int type = 500;
91 module_param(type, int, 0);
92 MODULE_PARM_DESC(type,
93 "WDT501-P Card type (500 or 501, default=500)");
99 static void wdt_ctr_mode(int ctr, int mode)
107 static void wdt_ctr_load(int ctr, int val)
109 outb_p(val&0xFF, WDT_COUNT0+ctr);
110 outb_p(val>>8, WDT_COUNT0+ctr);
116 * Start the watchdog driver.
119 static int wdt_start(void)
122 spin_lock_irqsave(&wdt_lock, flags);
123 inb_p(WDT_DC); /* Disable watchdog */
124 wdt_ctr_mode(0, 3); /* Program CTR0 for Mode 3:
125 Square Wave Generator */
126 wdt_ctr_mode(1, 2); /* Program CTR1 for Mode 2:
128 wdt_ctr_mode(2, 0); /* Program CTR2 for Mode 0:
129 Pulse on Terminal Count */
130 wdt_ctr_load(0, 8948); /* Count at 100Hz */
131 wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */
132 wdt_ctr_load(2, 65535); /* Length of reset pulse */
133 outb_p(0, WDT_DC); /* Enable watchdog */
134 spin_unlock_irqrestore(&wdt_lock, flags);
141 * Stop the watchdog driver.
144 static int wdt_stop(void)
147 spin_lock_irqsave(&wdt_lock, flags);
148 /* Turn the card off */
149 inb_p(WDT_DC); /* Disable watchdog */
150 wdt_ctr_load(2, 0); /* 0 length reset pulses now */
151 spin_unlock_irqrestore(&wdt_lock, flags);
158 * Reload counter one with the watchdog heartbeat. We don't bother
159 * reloading the cascade counter.
162 static void wdt_ping(void)
165 spin_lock_irqsave(&wdt_lock, flags);
166 /* Write a watchdog value */
167 inb_p(WDT_DC); /* Disable watchdog */
168 wdt_ctr_mode(1, 2); /* Re-Program CTR1 for Mode 2:
170 wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */
171 outb_p(0, WDT_DC); /* Enable watchdog */
172 spin_unlock_irqrestore(&wdt_lock, flags);
177 * @t: the new heartbeat value that needs to be set.
179 * Set a new heartbeat value for the watchdog device. If the heartbeat
180 * value is incorrect we keep the old value and return -EINVAL. If
181 * successful we return 0.
184 static int wdt_set_heartbeat(int t)
186 if (t < 1 || t > 65535)
190 wd_heartbeat = t * 100;
197 * Extract the status information from a WDT watchdog device. There are
198 * several board variants so we have to know which bits are valid. Some
199 * bits default to one and some to zero in order to be maximally painful.
201 * we then map the bits onto the status ioctl flags.
204 static int wdt_get_status(void)
206 unsigned char new_status;
210 spin_lock_irqsave(&wdt_lock, flags);
211 new_status = inb_p(WDT_SR);
212 spin_unlock_irqrestore(&wdt_lock, flags);
214 if (new_status & WDC_SR_ISOI0)
215 status |= WDIOF_EXTERN1;
216 if (new_status & WDC_SR_ISII1)
217 status |= WDIOF_EXTERN2;
219 if (!(new_status & WDC_SR_TGOOD))
220 status |= WDIOF_OVERHEAT;
221 if (!(new_status & WDC_SR_PSUOVER))
222 status |= WDIOF_POWEROVER;
223 if (!(new_status & WDC_SR_PSUUNDR))
224 status |= WDIOF_POWERUNDER;
226 if (!(new_status & WDC_SR_FANGOOD))
227 status |= WDIOF_FANFAULT;
234 * wdt_get_temperature:
236 * Reports the temperature in degrees Fahrenheit. The API is in
237 * farenheit. It was designed by an imperial measurement luddite.
240 static int wdt_get_temperature(void)
245 spin_lock_irqsave(&wdt_lock, flags);
247 spin_unlock_irqrestore(&wdt_lock, flags);
248 return (c * 11 / 15) + 7;
251 static void wdt_decode_501(int status)
253 if (!(status & WDC_SR_TGOOD))
254 printk(KERN_CRIT "Overheat alarm.(%d)\n", inb_p(WDT_RT));
255 if (!(status & WDC_SR_PSUOVER))
256 printk(KERN_CRIT "PSU over voltage.\n");
257 if (!(status & WDC_SR_PSUUNDR))
258 printk(KERN_CRIT "PSU under voltage.\n");
263 * @irq: Interrupt number
264 * @dev_id: Unused as we don't allow multiple devices.
266 * Handle an interrupt from the board. These are raised when the status
267 * map changes in what the board considers an interesting way. That means
268 * a failure condition occurring.
271 static irqreturn_t wdt_interrupt(int irq, void *dev_id)
274 * Read the status register see what is up and
277 unsigned char status;
279 spin_lock(&wdt_lock);
280 status = inb_p(WDT_SR);
282 printk(KERN_CRIT "WDT status %d\n", status);
285 wdt_decode_501(status);
287 if (!(status & WDC_SR_FANGOOD))
288 printk(KERN_CRIT "Possible fan fault.\n");
291 if (!(status & WDC_SR_WCCR)) {
292 #ifdef SOFTWARE_REBOOT
294 printk(KERN_CRIT "Would Reboot.\n");
296 printk(KERN_CRIT "Initiating system reboot.\n");
300 printk(KERN_CRIT "Reset in 5ms.\n");
303 spin_unlock(&wdt_lock);
310 * @file: file handle to the watchdog
311 * @buf: buffer to write (unused as data does not matter here
312 * @count: count of bytes
313 * @ppos: pointer to the position to write. No seeks allowed
315 * A write to a watchdog device is defined as a keepalive signal. Any
316 * write of data will do, as we we don't define content meaning.
319 static ssize_t wdt_write(struct file *file, const char __user *buf,
320 size_t count, loff_t *ppos)
326 /* In case it was set long ago */
329 for (i = 0; i != count; i++) {
331 if (get_user(c, buf + i))
344 * @file: file handle to the device
345 * @cmd: watchdog command
346 * @arg: argument pointer
348 * The watchdog API defines a common set of functions for all watchdogs
349 * according to their available features. We only actually usefully support
350 * querying capabilities and current status.
353 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
355 void __user *argp = (void __user *)arg;
356 int __user *p = argp;
360 struct watchdog_info ident = {
361 .options = WDIOF_SETTIMEOUT|
364 .firmware_version = 1,
365 .identity = "WDT500/501",
368 /* Add options according to the card we have */
369 ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);
371 ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|
374 ident.options |= WDIOF_FANFAULT;
378 case WDIOC_GETSUPPORT:
379 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
380 case WDIOC_GETSTATUS:
381 status = wdt_get_status();
382 return put_user(status, p);
383 case WDIOC_GETBOOTSTATUS:
384 return put_user(0, p);
385 case WDIOC_KEEPALIVE:
388 case WDIOC_SETTIMEOUT:
389 if (get_user(new_heartbeat, p))
391 if (wdt_set_heartbeat(new_heartbeat))
395 case WDIOC_GETTIMEOUT:
396 return put_user(heartbeat, p);
404 * @inode: inode of device
405 * @file: file handle to device
407 * The watchdog device has been opened. The watchdog device is single
408 * open and on opening we load the counters. Counter zero is a 100Hz
409 * cascade, into counter 1 which downcounts to reboot. When the counter
410 * triggers counter 2 downcounts the length of the reset pulse which
411 * set set to be as long as possible.
414 static int wdt_open(struct inode *inode, struct file *file)
416 if (test_and_set_bit(0, &wdt_is_open))
422 return nonseekable_open(inode, file);
427 * @inode: inode to board
428 * @file: file handle to board
430 * The watchdog has a configurable API. There is a religious dispute
431 * between people who want their watchdog to be able to shut down and
432 * those who want to be sure if the watchdog manager dies the machine
433 * reboots. In the former case we disable the counters, in the latter
434 * case you have to open it again very soon.
437 static int wdt_release(struct inode *inode, struct file *file)
439 if (expect_close == 42) {
441 clear_bit(0, &wdt_is_open);
444 "wdt: WDT device closed unexpectedly. WDT will not stop!\n");
453 * @file: file handle to the watchdog board
454 * @buf: buffer to write 1 byte into
455 * @count: length of buffer
456 * @ptr: offset (no seek allowed)
458 * Temp_read reports the temperature in degrees Fahrenheit. The API is in
459 * farenheit. It was designed by an imperial measurement luddite.
462 static ssize_t wdt_temp_read(struct file *file, char __user *buf,
463 size_t count, loff_t *ptr)
465 int temperature = wdt_get_temperature();
467 if (copy_to_user(buf, &temperature, 1))
475 * @inode: inode of device
476 * @file: file handle to device
478 * The temperature device has been opened.
481 static int wdt_temp_open(struct inode *inode, struct file *file)
483 return nonseekable_open(inode, file);
488 * @inode: inode to board
489 * @file: file handle to board
491 * The temperature device has been closed.
494 static int wdt_temp_release(struct inode *inode, struct file *file)
501 * @this: our notifier block
502 * @code: the event being reported
505 * Our notifier is called on system shutdowns. We want to turn the card
506 * off at reboot otherwise the machine will reboot again during memory
507 * test or worse yet during the following fsck. This would suck, in fact
508 * trust me - if it happens it does suck.
511 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
514 if (code == SYS_DOWN || code == SYS_HALT)
524 static const struct file_operations wdt_fops = {
525 .owner = THIS_MODULE,
528 .unlocked_ioctl = wdt_ioctl,
530 .release = wdt_release,
533 static struct miscdevice wdt_miscdev = {
534 .minor = WATCHDOG_MINOR,
539 static const struct file_operations wdt_temp_fops = {
540 .owner = THIS_MODULE,
542 .read = wdt_temp_read,
543 .open = wdt_temp_open,
544 .release = wdt_temp_release,
547 static struct miscdevice temp_miscdev = {
549 .name = "temperature",
550 .fops = &wdt_temp_fops,
554 * The WDT card needs to learn about soft shutdowns in order to
555 * turn the timebomb registers off.
558 static struct notifier_block wdt_notifier = {
559 .notifier_call = wdt_notify_sys,
565 * Unload the watchdog. You cannot do this with any file handles open.
566 * If your watchdog is set to continue ticking on close and you unload
567 * it, well it keeps ticking. We won't get the interrupt but the board
568 * will not touch PC memory so all is fine. You just have to load a new
569 * module in 60 seconds or reboot.
572 static void __exit wdt_exit(void)
574 misc_deregister(&wdt_miscdev);
576 misc_deregister(&temp_miscdev);
577 unregister_reboot_notifier(&wdt_notifier);
579 release_region(io, 8);
585 * Set up the WDT watchdog board. All we have to do is grab the
586 * resources we require and bitch if anyone beat us to them.
587 * The open() function will actually kick the board off.
590 static int __init wdt_init(void)
594 if (type != 500 && type != 501) {
595 printk(KERN_ERR "wdt: unknown card type '%d'.\n", type);
599 /* Check that the heartbeat value is within it's range;
600 if not reset to the default */
601 if (wdt_set_heartbeat(heartbeat)) {
602 wdt_set_heartbeat(WD_TIMO);
603 printk(KERN_INFO "wdt: heartbeat value must be "
604 "0 < heartbeat < 65536, using %d\n", WD_TIMO);
607 if (!request_region(io, 8, "wdt501p")) {
609 "wdt: I/O address 0x%04x already in use\n", io);
614 ret = request_irq(irq, wdt_interrupt, 0, "wdt501p", NULL);
616 printk(KERN_ERR "wdt: IRQ %d is not free.\n", irq);
620 ret = register_reboot_notifier(&wdt_notifier);
623 "wdt: cannot register reboot notifier (err=%d)\n", ret);
628 ret = misc_register(&temp_miscdev);
630 printk(KERN_ERR "wdt: cannot register miscdev "
631 "on minor=%d (err=%d)\n", TEMP_MINOR, ret);
636 ret = misc_register(&wdt_miscdev);
639 "wdt: cannot register miscdev on minor=%d (err=%d)\n",
640 WATCHDOG_MINOR, ret);
644 printk(KERN_INFO "WDT500/501-P driver 0.10 "
645 "at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",
646 io, irq, heartbeat, nowayout);
648 printk(KERN_INFO "wdt: Fan Tachometer is %s\n",
649 (tachometer ? "Enabled" : "Disabled"));
654 misc_deregister(&temp_miscdev);
656 unregister_reboot_notifier(&wdt_notifier);
660 release_region(io, 8);
665 module_init(wdt_init);
666 module_exit(wdt_exit);
668 MODULE_AUTHOR("Alan Cox");
669 MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)");
670 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
671 MODULE_ALIAS_MISCDEV(TEMP_MINOR);
672 MODULE_LICENSE("GPL");