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>
49 #include <asm/system.h>
52 static unsigned long wdt_is_open;
53 static char expect_close;
59 #define WD_TIMO 60 /* Default heartbeat = 60 seconds */
61 static int heartbeat = WD_TIMO;
62 static int wd_heartbeat;
63 module_param(heartbeat, int, 0);
64 MODULE_PARM_DESC(heartbeat,
65 "Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default="
66 __MODULE_STRING(WD_TIMO) ")");
68 static int nowayout = WATCHDOG_NOWAYOUT;
69 module_param(nowayout, int, 0);
70 MODULE_PARM_DESC(nowayout,
71 "Watchdog cannot be stopped once started (default="
72 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
74 /* You must set these - there is no sane way to probe for this board. */
75 static int io = 0x240;
78 static DEFINE_SPINLOCK(wdt_lock);
80 module_param(io, int, 0);
81 MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
82 module_param(irq, int, 0);
83 MODULE_PARM_DESC(irq, "WDT irq (default=11)");
85 /* Support for the Fan Tachometer on the WDT501-P */
86 static int tachometer;
87 module_param(tachometer, int, 0);
88 MODULE_PARM_DESC(tachometer,
89 "WDT501-P Fan Tachometer support (0=disable, default=0)");
91 static int type = 500;
92 module_param(type, int, 0);
93 MODULE_PARM_DESC(type,
94 "WDT501-P Card type (500 or 501 , default=500)");
100 static void wdt_ctr_mode(int ctr, int mode)
108 static void wdt_ctr_load(int ctr, int val)
110 outb_p(val&0xFF, WDT_COUNT0+ctr);
111 outb_p(val>>8, WDT_COUNT0+ctr);
117 * Start the watchdog driver.
120 static int wdt_start(void)
123 spin_lock_irqsave(&wdt_lock, flags);
124 inb_p(WDT_DC); /* Disable watchdog */
125 wdt_ctr_mode(0, 3); /* Program CTR0 for Mode 3:
126 Square Wave Generator */
127 wdt_ctr_mode(1, 2); /* Program CTR1 for Mode 2:
129 wdt_ctr_mode(2, 0); /* Program CTR2 for Mode 0:
130 Pulse on Terminal Count */
131 wdt_ctr_load(0, 8948); /* Count at 100Hz */
132 wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */
133 wdt_ctr_load(2, 65535); /* Length of reset pulse */
134 outb_p(0, WDT_DC); /* Enable watchdog */
135 spin_unlock_irqrestore(&wdt_lock, flags);
142 * Stop the watchdog driver.
145 static int wdt_stop(void)
148 spin_lock_irqsave(&wdt_lock, flags);
149 /* Turn the card off */
150 inb_p(WDT_DC); /* Disable watchdog */
151 wdt_ctr_load(2, 0); /* 0 length reset pulses now */
152 spin_unlock_irqrestore(&wdt_lock, flags);
159 * Reload counter one with the watchdog heartbeat. We don't bother
160 * reloading the cascade counter.
163 static void wdt_ping(void)
166 spin_lock_irqsave(&wdt_lock, flags);
167 /* Write a watchdog value */
168 inb_p(WDT_DC); /* Disable watchdog */
169 wdt_ctr_mode(1, 2); /* Re-Program CTR1 for Mode 2:
171 wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */
172 outb_p(0, WDT_DC); /* Enable watchdog */
173 spin_unlock_irqrestore(&wdt_lock, flags);
178 * @t: the new heartbeat value that needs to be set.
180 * Set a new heartbeat value for the watchdog device. If the heartbeat
181 * value is incorrect we keep the old value and return -EINVAL. If
182 * successful we return 0.
185 static int wdt_set_heartbeat(int t)
187 if (t < 1 || t > 65535)
191 wd_heartbeat = t * 100;
198 * Extract the status information from a WDT watchdog device. There are
199 * several board variants so we have to know which bits are valid. Some
200 * bits default to one and some to zero in order to be maximally painful.
202 * we then map the bits onto the status ioctl flags.
205 static int wdt_get_status(void)
207 unsigned char new_status;
211 spin_lock_irqsave(&wdt_lock, flags);
212 new_status = inb_p(WDT_SR);
213 spin_unlock_irqrestore(&wdt_lock, flags);
215 if (new_status & WDC_SR_ISOI0)
216 status |= WDIOF_EXTERN1;
217 if (new_status & WDC_SR_ISII1)
218 status |= WDIOF_EXTERN2;
220 if (!(new_status & WDC_SR_TGOOD))
221 status |= WDIOF_OVERHEAT;
222 if (!(new_status & WDC_SR_PSUOVER))
223 status |= WDIOF_POWEROVER;
224 if (!(new_status & WDC_SR_PSUUNDR))
225 status |= WDIOF_POWERUNDER;
227 if (!(new_status & WDC_SR_FANGOOD))
228 status |= WDIOF_FANFAULT;
235 * wdt_get_temperature:
237 * Reports the temperature in degrees Fahrenheit. The API is in
238 * farenheit. It was designed by an imperial measurement luddite.
241 static int wdt_get_temperature(void)
246 spin_lock_irqsave(&wdt_lock, flags);
248 spin_unlock_irqrestore(&wdt_lock, flags);
249 return (c * 11 / 15) + 7;
252 static void wdt_decode_501(int status)
254 if (!(status & WDC_SR_TGOOD))
255 printk(KERN_CRIT "Overheat alarm.(%d)\n", inb_p(WDT_RT));
256 if (!(status & WDC_SR_PSUOVER))
257 printk(KERN_CRIT "PSU over voltage.\n");
258 if (!(status & WDC_SR_PSUUNDR))
259 printk(KERN_CRIT "PSU under voltage.\n");
264 * @irq: Interrupt number
265 * @dev_id: Unused as we don't allow multiple devices.
267 * Handle an interrupt from the board. These are raised when the status
268 * map changes in what the board considers an interesting way. That means
269 * a failure condition occurring.
272 static irqreturn_t wdt_interrupt(int irq, void *dev_id)
275 * Read the status register see what is up and
278 unsigned char status;
280 spin_lock(&wdt_lock);
281 status = inb_p(WDT_SR);
283 printk(KERN_CRIT "WDT status %d\n", status);
286 wdt_decode_501(status);
288 if (!(status & WDC_SR_FANGOOD))
289 printk(KERN_CRIT "Possible fan fault.\n");
292 if (!(status & WDC_SR_WCCR)) {
293 #ifdef SOFTWARE_REBOOT
295 printk(KERN_CRIT "Would Reboot.\n");
297 printk(KERN_CRIT "Initiating system reboot.\n");
301 printk(KERN_CRIT "Reset in 5ms.\n");
304 spin_unlock(&wdt_lock);
311 * @file: file handle to the watchdog
312 * @buf: buffer to write (unused as data does not matter here
313 * @count: count of bytes
314 * @ppos: pointer to the position to write. No seeks allowed
316 * A write to a watchdog device is defined as a keepalive signal. Any
317 * write of data will do, as we we don't define content meaning.
320 static ssize_t wdt_write(struct file *file, const char __user *buf,
321 size_t count, loff_t *ppos)
327 /* In case it was set long ago */
330 for (i = 0; i != count; i++) {
332 if (get_user(c, buf + i))
345 * @file: file handle to the device
346 * @cmd: watchdog command
347 * @arg: argument pointer
349 * The watchdog API defines a common set of functions for all watchdogs
350 * according to their available features. We only actually usefully support
351 * querying capabilities and current status.
354 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
356 void __user *argp = (void __user *)arg;
357 int __user *p = argp;
361 static struct watchdog_info ident = {
362 .options = WDIOF_SETTIMEOUT|
365 .firmware_version = 1,
366 .identity = "WDT500/501",
369 /* Add options according to the card we have */
370 ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);
372 ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|
375 ident.options |= WDIOF_FANFAULT;
379 case WDIOC_GETSUPPORT:
380 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
381 case WDIOC_GETSTATUS:
382 status = wdt_get_status();
383 return put_user(status, p);
384 case WDIOC_GETBOOTSTATUS:
385 return put_user(0, p);
386 case WDIOC_KEEPALIVE:
389 case WDIOC_SETTIMEOUT:
390 if (get_user(new_heartbeat, p))
392 if (wdt_set_heartbeat(new_heartbeat))
396 case WDIOC_GETTIMEOUT:
397 return put_user(heartbeat, p);
405 * @inode: inode of device
406 * @file: file handle to device
408 * The watchdog device has been opened. The watchdog device is single
409 * open and on opening we load the counters. Counter zero is a 100Hz
410 * cascade, into counter 1 which downcounts to reboot. When the counter
411 * triggers counter 2 downcounts the length of the reset pulse which
412 * set set to be as long as possible.
415 static int wdt_open(struct inode *inode, struct file *file)
417 if (test_and_set_bit(0, &wdt_is_open))
423 return nonseekable_open(inode, file);
428 * @inode: inode to board
429 * @file: file handle to board
431 * The watchdog has a configurable API. There is a religious dispute
432 * between people who want their watchdog to be able to shut down and
433 * those who want to be sure if the watchdog manager dies the machine
434 * reboots. In the former case we disable the counters, in the latter
435 * case you have to open it again very soon.
438 static int wdt_release(struct inode *inode, struct file *file)
440 if (expect_close == 42) {
442 clear_bit(0, &wdt_is_open);
445 "wdt: WDT device closed unexpectedly. WDT will not stop!\n");
454 * @file: file handle to the watchdog board
455 * @buf: buffer to write 1 byte into
456 * @count: length of buffer
457 * @ptr: offset (no seek allowed)
459 * Temp_read reports the temperature in degrees Fahrenheit. The API is in
460 * farenheit. It was designed by an imperial measurement luddite.
463 static ssize_t wdt_temp_read(struct file *file, char __user *buf,
464 size_t count, loff_t *ptr)
466 int temperature = wdt_get_temperature();
468 if (copy_to_user(buf, &temperature, 1))
476 * @inode: inode of device
477 * @file: file handle to device
479 * The temperature device has been opened.
482 static int wdt_temp_open(struct inode *inode, struct file *file)
484 return nonseekable_open(inode, file);
489 * @inode: inode to board
490 * @file: file handle to board
492 * The temperature device has been closed.
495 static int wdt_temp_release(struct inode *inode, struct file *file)
502 * @this: our notifier block
503 * @code: the event being reported
506 * Our notifier is called on system shutdowns. We want to turn the card
507 * off at reboot otherwise the machine will reboot again during memory
508 * test or worse yet during the following fsck. This would suck, in fact
509 * trust me - if it happens it does suck.
512 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
515 if (code == SYS_DOWN || code == SYS_HALT)
525 static const struct file_operations wdt_fops = {
526 .owner = THIS_MODULE,
529 .unlocked_ioctl = wdt_ioctl,
531 .release = wdt_release,
534 static struct miscdevice wdt_miscdev = {
535 .minor = WATCHDOG_MINOR,
540 static const struct file_operations wdt_temp_fops = {
541 .owner = THIS_MODULE,
543 .read = wdt_temp_read,
544 .open = wdt_temp_open,
545 .release = wdt_temp_release,
548 static struct miscdevice temp_miscdev = {
550 .name = "temperature",
551 .fops = &wdt_temp_fops,
555 * The WDT card needs to learn about soft shutdowns in order to
556 * turn the timebomb registers off.
559 static struct notifier_block wdt_notifier = {
560 .notifier_call = wdt_notify_sys,
566 * Unload the watchdog. You cannot do this with any file handles open.
567 * If your watchdog is set to continue ticking on close and you unload
568 * it, well it keeps ticking. We won't get the interrupt but the board
569 * will not touch PC memory so all is fine. You just have to load a new
570 * module in 60 seconds or reboot.
573 static void __exit wdt_exit(void)
575 misc_deregister(&wdt_miscdev);
577 misc_deregister(&temp_miscdev);
578 unregister_reboot_notifier(&wdt_notifier);
580 release_region(io, 8);
586 * Set up the WDT watchdog board. All we have to do is grab the
587 * resources we require and bitch if anyone beat us to them.
588 * The open() function will actually kick the board off.
591 static int __init wdt_init(void)
595 if (type != 500 && type != 501) {
596 printk(KERN_ERR "wdt: unknown card type '%d'.\n", type);
600 /* Check that the heartbeat value is within it's range;
601 if not reset to the default */
602 if (wdt_set_heartbeat(heartbeat)) {
603 wdt_set_heartbeat(WD_TIMO);
604 printk(KERN_INFO "wdt: heartbeat value must be "
605 "0 < heartbeat < 65536, using %d\n", WD_TIMO);
608 if (!request_region(io, 8, "wdt501p")) {
610 "wdt: I/O address 0x%04x already in use\n", io);
615 ret = request_irq(irq, wdt_interrupt, IRQF_DISABLED, "wdt501p", NULL);
617 printk(KERN_ERR "wdt: IRQ %d is not free.\n", irq);
621 ret = register_reboot_notifier(&wdt_notifier);
624 "wdt: cannot register reboot notifier (err=%d)\n", ret);
629 ret = misc_register(&temp_miscdev);
631 printk(KERN_ERR "wdt: cannot register miscdev "
632 "on minor=%d (err=%d)\n", TEMP_MINOR, ret);
637 ret = misc_register(&wdt_miscdev);
640 "wdt: cannot register miscdev on minor=%d (err=%d)\n",
641 WATCHDOG_MINOR, ret);
645 printk(KERN_INFO "WDT500/501-P driver 0.10 "
646 "at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",
647 io, irq, heartbeat, nowayout);
649 printk(KERN_INFO "wdt: Fan Tachometer is %s\n",
650 (tachometer ? "Enabled" : "Disabled"));
655 misc_deregister(&temp_miscdev);
657 unregister_reboot_notifier(&wdt_notifier);
661 release_region(io, 8);
666 module_init(wdt_init);
667 module_exit(wdt_exit);
669 MODULE_AUTHOR("Alan Cox");
670 MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)");
671 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
672 MODULE_ALIAS_MISCDEV(TEMP_MINOR);
673 MODULE_LICENSE("GPL");