Merge tag 'gpio-v3.13-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw...
[linux-2.6.git] / drivers / watchdog / wdt.c
blobe0206b5b7d8955526f9598a6cc012fcdfd090873
1 /*
2 * Industrial Computer Source WDT501 driver
4 * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
5 * All Rights Reserved.
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>
18 * Release 0.10.
20 * Fixes
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
24 * Matt Crocker).
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
30 * failures
31 * Joel Becker : Added WDIOC_GET/SETTIMEOUT
32 * Matt Domsch : Added nowayout module option
35 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
37 #include <linux/interrupt.h>
38 #include <linux/module.h>
39 #include <linux/moduleparam.h>
40 #include <linux/types.h>
41 #include <linux/miscdevice.h>
42 #include <linux/watchdog.h>
43 #include <linux/fs.h>
44 #include <linux/ioport.h>
45 #include <linux/notifier.h>
46 #include <linux/reboot.h>
47 #include <linux/init.h>
48 #include <linux/io.h>
49 #include <linux/uaccess.h>
51 #include "wd501p.h"
53 static unsigned long wdt_is_open;
54 static char expect_close;
57 * Module parameters
60 #define WD_TIMO 60 /* Default heartbeat = 60 seconds */
62 static int heartbeat = WD_TIMO;
63 static int wd_heartbeat;
64 module_param(heartbeat, int, 0);
65 MODULE_PARM_DESC(heartbeat,
66 "Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default="
67 __MODULE_STRING(WD_TIMO) ")");
69 static bool nowayout = WATCHDOG_NOWAYOUT;
70 module_param(nowayout, bool, 0);
71 MODULE_PARM_DESC(nowayout,
72 "Watchdog cannot be stopped once started (default="
73 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
75 /* You must set these - there is no sane way to probe for this board. */
76 static int io = 0x240;
77 static int irq = 11;
79 static DEFINE_SPINLOCK(wdt_lock);
81 module_param(io, int, 0);
82 MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
83 module_param(irq, int, 0);
84 MODULE_PARM_DESC(irq, "WDT irq (default=11)");
86 /* Support for the Fan Tachometer on the WDT501-P */
87 static int tachometer;
88 module_param(tachometer, int, 0);
89 MODULE_PARM_DESC(tachometer,
90 "WDT501-P Fan Tachometer support (0=disable, default=0)");
92 static int type = 500;
93 module_param(type, int, 0);
94 MODULE_PARM_DESC(type,
95 "WDT501-P Card type (500 or 501, default=500)");
98 * Programming support
101 static void wdt_ctr_mode(int ctr, int mode)
103 ctr <<= 6;
104 ctr |= 0x30;
105 ctr |= (mode << 1);
106 outb_p(ctr, WDT_CR);
109 static void wdt_ctr_load(int ctr, int val)
111 outb_p(val&0xFF, WDT_COUNT0+ctr);
112 outb_p(val>>8, WDT_COUNT0+ctr);
116 * wdt_start:
118 * Start the watchdog driver.
121 static int wdt_start(void)
123 unsigned long flags;
124 spin_lock_irqsave(&wdt_lock, flags);
125 inb_p(WDT_DC); /* Disable watchdog */
126 wdt_ctr_mode(0, 3); /* Program CTR0 for Mode 3:
127 Square Wave Generator */
128 wdt_ctr_mode(1, 2); /* Program CTR1 for Mode 2:
129 Rate Generator */
130 wdt_ctr_mode(2, 0); /* Program CTR2 for Mode 0:
131 Pulse on Terminal Count */
132 wdt_ctr_load(0, 8948); /* Count at 100Hz */
133 wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */
134 wdt_ctr_load(2, 65535); /* Length of reset pulse */
135 outb_p(0, WDT_DC); /* Enable watchdog */
136 spin_unlock_irqrestore(&wdt_lock, flags);
137 return 0;
141 * wdt_stop:
143 * Stop the watchdog driver.
146 static int wdt_stop(void)
148 unsigned long flags;
149 spin_lock_irqsave(&wdt_lock, flags);
150 /* Turn the card off */
151 inb_p(WDT_DC); /* Disable watchdog */
152 wdt_ctr_load(2, 0); /* 0 length reset pulses now */
153 spin_unlock_irqrestore(&wdt_lock, flags);
154 return 0;
158 * wdt_ping:
160 * Reload counter one with the watchdog heartbeat. We don't bother
161 * reloading the cascade counter.
164 static void wdt_ping(void)
166 unsigned long flags;
167 spin_lock_irqsave(&wdt_lock, flags);
168 /* Write a watchdog value */
169 inb_p(WDT_DC); /* Disable watchdog */
170 wdt_ctr_mode(1, 2); /* Re-Program CTR1 for Mode 2:
171 Rate Generator */
172 wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */
173 outb_p(0, WDT_DC); /* Enable watchdog */
174 spin_unlock_irqrestore(&wdt_lock, flags);
178 * wdt_set_heartbeat:
179 * @t: the new heartbeat value that needs to be set.
181 * Set a new heartbeat value for the watchdog device. If the heartbeat
182 * value is incorrect we keep the old value and return -EINVAL. If
183 * successful we return 0.
186 static int wdt_set_heartbeat(int t)
188 if (t < 1 || t > 65535)
189 return -EINVAL;
191 heartbeat = t;
192 wd_heartbeat = t * 100;
193 return 0;
197 * wdt_get_status:
199 * Extract the status information from a WDT watchdog device. There are
200 * several board variants so we have to know which bits are valid. Some
201 * bits default to one and some to zero in order to be maximally painful.
203 * we then map the bits onto the status ioctl flags.
206 static int wdt_get_status(void)
208 unsigned char new_status;
209 int status = 0;
210 unsigned long flags;
212 spin_lock_irqsave(&wdt_lock, flags);
213 new_status = inb_p(WDT_SR);
214 spin_unlock_irqrestore(&wdt_lock, flags);
216 if (new_status & WDC_SR_ISOI0)
217 status |= WDIOF_EXTERN1;
218 if (new_status & WDC_SR_ISII1)
219 status |= WDIOF_EXTERN2;
220 if (type == 501) {
221 if (!(new_status & WDC_SR_TGOOD))
222 status |= WDIOF_OVERHEAT;
223 if (!(new_status & WDC_SR_PSUOVER))
224 status |= WDIOF_POWEROVER;
225 if (!(new_status & WDC_SR_PSUUNDR))
226 status |= WDIOF_POWERUNDER;
227 if (tachometer) {
228 if (!(new_status & WDC_SR_FANGOOD))
229 status |= WDIOF_FANFAULT;
232 return status;
236 * wdt_get_temperature:
238 * Reports the temperature in degrees Fahrenheit. The API is in
239 * farenheit. It was designed by an imperial measurement luddite.
242 static int wdt_get_temperature(void)
244 unsigned short c;
245 unsigned long flags;
247 spin_lock_irqsave(&wdt_lock, flags);
248 c = inb_p(WDT_RT);
249 spin_unlock_irqrestore(&wdt_lock, flags);
250 return (c * 11 / 15) + 7;
253 static void wdt_decode_501(int status)
255 if (!(status & WDC_SR_TGOOD))
256 pr_crit("Overheat alarm (%d)\n", inb_p(WDT_RT));
257 if (!(status & WDC_SR_PSUOVER))
258 pr_crit("PSU over voltage\n");
259 if (!(status & WDC_SR_PSUUNDR))
260 pr_crit("PSU under voltage\n");
264 * wdt_interrupt:
265 * @irq: Interrupt number
266 * @dev_id: Unused as we don't allow multiple devices.
268 * Handle an interrupt from the board. These are raised when the status
269 * map changes in what the board considers an interesting way. That means
270 * a failure condition occurring.
273 static irqreturn_t wdt_interrupt(int irq, void *dev_id)
276 * Read the status register see what is up and
277 * then printk it.
279 unsigned char status;
281 spin_lock(&wdt_lock);
282 status = inb_p(WDT_SR);
284 pr_crit("WDT status %d\n", status);
286 if (type == 501) {
287 wdt_decode_501(status);
288 if (tachometer) {
289 if (!(status & WDC_SR_FANGOOD))
290 pr_crit("Possible fan fault\n");
293 if (!(status & WDC_SR_WCCR)) {
294 #ifdef SOFTWARE_REBOOT
295 #ifdef ONLY_TESTING
296 pr_crit("Would Reboot\n");
297 #else
298 pr_crit("Initiating system reboot\n");
299 emergency_restart();
300 #endif
301 #else
302 pr_crit("Reset in 5ms\n");
303 #endif
305 spin_unlock(&wdt_lock);
306 return IRQ_HANDLED;
311 * wdt_write:
312 * @file: file handle to the watchdog
313 * @buf: buffer to write (unused as data does not matter here
314 * @count: count of bytes
315 * @ppos: pointer to the position to write. No seeks allowed
317 * A write to a watchdog device is defined as a keepalive signal. Any
318 * write of data will do, as we we don't define content meaning.
321 static ssize_t wdt_write(struct file *file, const char __user *buf,
322 size_t count, loff_t *ppos)
324 if (count) {
325 if (!nowayout) {
326 size_t i;
328 /* In case it was set long ago */
329 expect_close = 0;
331 for (i = 0; i != count; i++) {
332 char c;
333 if (get_user(c, buf + i))
334 return -EFAULT;
335 if (c == 'V')
336 expect_close = 42;
339 wdt_ping();
341 return count;
345 * wdt_ioctl:
346 * @file: file handle to the device
347 * @cmd: watchdog command
348 * @arg: argument pointer
350 * The watchdog API defines a common set of functions for all watchdogs
351 * according to their available features. We only actually usefully support
352 * querying capabilities and current status.
355 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
357 void __user *argp = (void __user *)arg;
358 int __user *p = argp;
359 int new_heartbeat;
360 int status;
362 struct watchdog_info ident = {
363 .options = WDIOF_SETTIMEOUT|
364 WDIOF_MAGICCLOSE|
365 WDIOF_KEEPALIVEPING,
366 .firmware_version = 1,
367 .identity = "WDT500/501",
370 /* Add options according to the card we have */
371 ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);
372 if (type == 501) {
373 ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|
374 WDIOF_POWEROVER);
375 if (tachometer)
376 ident.options |= WDIOF_FANFAULT;
379 switch (cmd) {
380 case WDIOC_GETSUPPORT:
381 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
382 case WDIOC_GETSTATUS:
383 status = wdt_get_status();
384 return put_user(status, p);
385 case WDIOC_GETBOOTSTATUS:
386 return put_user(0, p);
387 case WDIOC_KEEPALIVE:
388 wdt_ping();
389 return 0;
390 case WDIOC_SETTIMEOUT:
391 if (get_user(new_heartbeat, p))
392 return -EFAULT;
393 if (wdt_set_heartbeat(new_heartbeat))
394 return -EINVAL;
395 wdt_ping();
396 /* Fall */
397 case WDIOC_GETTIMEOUT:
398 return put_user(heartbeat, p);
399 default:
400 return -ENOTTY;
405 * wdt_open:
406 * @inode: inode of device
407 * @file: file handle to device
409 * The watchdog device has been opened. The watchdog device is single
410 * open and on opening we load the counters. Counter zero is a 100Hz
411 * cascade, into counter 1 which downcounts to reboot. When the counter
412 * triggers counter 2 downcounts the length of the reset pulse which
413 * set set to be as long as possible.
416 static int wdt_open(struct inode *inode, struct file *file)
418 if (test_and_set_bit(0, &wdt_is_open))
419 return -EBUSY;
421 * Activate
423 wdt_start();
424 return nonseekable_open(inode, file);
428 * wdt_release:
429 * @inode: inode to board
430 * @file: file handle to board
432 * The watchdog has a configurable API. There is a religious dispute
433 * between people who want their watchdog to be able to shut down and
434 * those who want to be sure if the watchdog manager dies the machine
435 * reboots. In the former case we disable the counters, in the latter
436 * case you have to open it again very soon.
439 static int wdt_release(struct inode *inode, struct file *file)
441 if (expect_close == 42) {
442 wdt_stop();
443 clear_bit(0, &wdt_is_open);
444 } else {
445 pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");
446 wdt_ping();
448 expect_close = 0;
449 return 0;
453 * wdt_temp_read:
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))
469 return -EFAULT;
471 return 1;
475 * wdt_temp_open:
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);
488 * wdt_temp_release:
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)
497 return 0;
501 * notify_sys:
502 * @this: our notifier block
503 * @code: the event being reported
504 * @unused: unused
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,
513 void *unused)
515 if (code == SYS_DOWN || code == SYS_HALT)
516 wdt_stop();
517 return NOTIFY_DONE;
521 * Kernel Interfaces
525 static const struct file_operations wdt_fops = {
526 .owner = THIS_MODULE,
527 .llseek = no_llseek,
528 .write = wdt_write,
529 .unlocked_ioctl = wdt_ioctl,
530 .open = wdt_open,
531 .release = wdt_release,
534 static struct miscdevice wdt_miscdev = {
535 .minor = WATCHDOG_MINOR,
536 .name = "watchdog",
537 .fops = &wdt_fops,
540 static const struct file_operations wdt_temp_fops = {
541 .owner = THIS_MODULE,
542 .llseek = no_llseek,
543 .read = wdt_temp_read,
544 .open = wdt_temp_open,
545 .release = wdt_temp_release,
548 static struct miscdevice temp_miscdev = {
549 .minor = TEMP_MINOR,
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,
564 * cleanup_module:
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);
576 if (type == 501)
577 misc_deregister(&temp_miscdev);
578 unregister_reboot_notifier(&wdt_notifier);
579 free_irq(irq, NULL);
580 release_region(io, 8);
584 * wdt_init:
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)
593 int ret;
595 if (type != 500 && type != 501) {
596 pr_err("unknown card type '%d'\n", type);
597 return -ENODEV;
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 pr_info("heartbeat value must be 0 < heartbeat < 65536, using %d\n",
605 WD_TIMO);
608 if (!request_region(io, 8, "wdt501p")) {
609 pr_err("I/O address 0x%04x already in use\n", io);
610 ret = -EBUSY;
611 goto out;
614 ret = request_irq(irq, wdt_interrupt, 0, "wdt501p", NULL);
615 if (ret) {
616 pr_err("IRQ %d is not free\n", irq);
617 goto outreg;
620 ret = register_reboot_notifier(&wdt_notifier);
621 if (ret) {
622 pr_err("cannot register reboot notifier (err=%d)\n", ret);
623 goto outirq;
626 if (type == 501) {
627 ret = misc_register(&temp_miscdev);
628 if (ret) {
629 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
630 TEMP_MINOR, ret);
631 goto outrbt;
635 ret = misc_register(&wdt_miscdev);
636 if (ret) {
637 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
638 WATCHDOG_MINOR, ret);
639 goto outmisc;
642 pr_info("WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",
643 io, irq, heartbeat, nowayout);
644 if (type == 501)
645 pr_info("Fan Tachometer is %s\n",
646 tachometer ? "Enabled" : "Disabled");
647 return 0;
649 outmisc:
650 if (type == 501)
651 misc_deregister(&temp_miscdev);
652 outrbt:
653 unregister_reboot_notifier(&wdt_notifier);
654 outirq:
655 free_irq(irq, NULL);
656 outreg:
657 release_region(io, 8);
658 out:
659 return ret;
662 module_init(wdt_init);
663 module_exit(wdt_exit);
665 MODULE_AUTHOR("Alan Cox");
666 MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)");
667 MODULE_LICENSE("GPL");