2 * W83877F Computer Watchdog Timer driver
4 * Based on acquirewdt.c by Alan Cox,
5 * and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net>
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 * The authors do NOT admit liability nor provide warranty for
13 * any of this software. This material is provided "AS-IS" in
14 * the hope that it may be useful for others.
16 * (c) Copyright 2001 Scott Jennings <linuxdrivers@oro.net>
18 * 4/19 - 2001 [Initial revision]
19 * 9/27 - 2001 Added spinlocking
20 * 4/12 - 2002 [rob@osinvestor.com] Eliminate extra comments
22 * Eliminate extra spin_unlock
23 * Added KERN_* tags to printks
24 * add CONFIG_WATCHDOG_NOWAYOUT support
25 * fix possible wdt_is_open race
26 * changed watchdog_info to correctly reflect what
28 * added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS,
30 * WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls
31 * 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces
32 * added extra printk's for startup problems
34 * made timeout (the emulated heartbeat) a
36 * made the keepalive ping an internal subroutine
38 * This WDT driver is different from most other Linux WDT
39 * drivers in that the driver will ping the watchdog by itself,
40 * because this particular WDT has a very short timeout (1.6
41 * seconds) and it would be insane to count on any userspace
42 * daemon always getting scheduled within that time frame.
45 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
47 #include <linux/module.h>
48 #include <linux/moduleparam.h>
49 #include <linux/types.h>
50 #include <linux/timer.h>
51 #include <linux/jiffies.h>
52 #include <linux/miscdevice.h>
53 #include <linux/watchdog.h>
55 #include <linux/ioport.h>
56 #include <linux/notifier.h>
57 #include <linux/reboot.h>
58 #include <linux/init.h>
60 #include <linux/uaccess.h>
62 #define OUR_NAME "w83877f_wdt"
64 #define ENABLE_W83877F_PORT 0x3F0
65 #define ENABLE_W83877F 0x87
66 #define DISABLE_W83877F 0xAA
67 #define WDT_PING 0x443
68 #define WDT_REGISTER 0x14
69 #define WDT_ENABLE 0x9C
70 #define WDT_DISABLE 0x8C
73 * The W83877F seems to be fixed at 1.6s timeout (at least on the
74 * EMACS PC-104 board I'm using). If we reset the watchdog every
75 * ~250ms we should be safe. */
77 #define WDT_INTERVAL (HZ/4+1)
80 * We must not require too good response from the userspace daemon.
81 * Here we require the userspace daemon to send us a heartbeat
82 * char to /dev/watchdog every 30 seconds.
85 #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
86 /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
87 static int timeout
= WATCHDOG_TIMEOUT
;
88 module_param(timeout
, int, 0);
89 MODULE_PARM_DESC(timeout
,
90 "Watchdog timeout in seconds. (1<=timeout<=3600, default="
91 __MODULE_STRING(WATCHDOG_TIMEOUT
) ")");
94 static bool nowayout
= WATCHDOG_NOWAYOUT
;
95 module_param(nowayout
, bool, 0);
96 MODULE_PARM_DESC(nowayout
,
97 "Watchdog cannot be stopped once started (default="
98 __MODULE_STRING(WATCHDOG_NOWAYOUT
) ")");
100 static void wdt_timer_ping(struct timer_list
*);
101 static DEFINE_TIMER(timer
, wdt_timer_ping
);
102 static unsigned long next_heartbeat
;
103 static unsigned long wdt_is_open
;
104 static char wdt_expect_close
;
105 static DEFINE_SPINLOCK(wdt_spinlock
);
111 static void wdt_timer_ping(struct timer_list
*unused
)
113 /* If we got a heartbeat pulse within the WDT_US_INTERVAL
114 * we agree to ping the WDT
116 if (time_before(jiffies
, next_heartbeat
)) {
118 spin_lock(&wdt_spinlock
);
120 /* Ping the WDT by reading from WDT_PING */
123 /* Re-set the timer interval */
124 mod_timer(&timer
, jiffies
+ WDT_INTERVAL
);
126 spin_unlock(&wdt_spinlock
);
129 pr_warn("Heartbeat lost! Will not ping the watchdog\n");
136 static void wdt_change(int writeval
)
139 spin_lock_irqsave(&wdt_spinlock
, flags
);
144 /* make W83877F available */
145 outb_p(ENABLE_W83877F
, ENABLE_W83877F_PORT
);
146 outb_p(ENABLE_W83877F
, ENABLE_W83877F_PORT
);
148 /* enable watchdog */
149 outb_p(WDT_REGISTER
, ENABLE_W83877F_PORT
);
150 outb_p(writeval
, ENABLE_W83877F_PORT
+1);
152 /* lock the W8387FF away */
153 outb_p(DISABLE_W83877F
, ENABLE_W83877F_PORT
);
155 spin_unlock_irqrestore(&wdt_spinlock
, flags
);
158 static void wdt_startup(void)
160 next_heartbeat
= jiffies
+ (timeout
* HZ
);
162 /* Start the timer */
163 mod_timer(&timer
, jiffies
+ WDT_INTERVAL
);
165 wdt_change(WDT_ENABLE
);
167 pr_info("Watchdog timer is now enabled\n");
170 static void wdt_turnoff(void)
175 wdt_change(WDT_DISABLE
);
177 pr_info("Watchdog timer is now disabled...\n");
180 static void wdt_keepalive(void)
183 next_heartbeat
= jiffies
+ (timeout
* HZ
);
187 * /dev/watchdog handling
190 static ssize_t
fop_write(struct file
*file
, const char __user
*buf
,
191 size_t count
, loff_t
*ppos
)
193 /* See if we got the magic character 'V' and reload the timer */
198 /* note: just in case someone wrote the magic
199 character five months ago... */
200 wdt_expect_close
= 0;
202 /* scan to see whether or not we got the
204 for (ofs
= 0; ofs
!= count
; ofs
++) {
206 if (get_user(c
, buf
+ ofs
))
209 wdt_expect_close
= 42;
213 /* someone wrote to us, we should restart timer */
219 static int fop_open(struct inode
*inode
, struct file
*file
)
221 /* Just in case we're already talking to someone... */
222 if (test_and_set_bit(0, &wdt_is_open
))
225 /* Good, fire up the show */
227 return stream_open(inode
, file
);
230 static int fop_close(struct inode
*inode
, struct file
*file
)
232 if (wdt_expect_close
== 42)
236 pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");
238 clear_bit(0, &wdt_is_open
);
239 wdt_expect_close
= 0;
243 static long fop_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
245 void __user
*argp
= (void __user
*)arg
;
246 int __user
*p
= argp
;
247 static const struct watchdog_info ident
= {
248 .options
= WDIOF_KEEPALIVEPING
| WDIOF_SETTIMEOUT
250 .firmware_version
= 1,
251 .identity
= "W83877F",
255 case WDIOC_GETSUPPORT
:
256 return copy_to_user(argp
, &ident
, sizeof(ident
)) ? -EFAULT
: 0;
257 case WDIOC_GETSTATUS
:
258 case WDIOC_GETBOOTSTATUS
:
259 return put_user(0, p
);
260 case WDIOC_SETOPTIONS
:
262 int new_options
, retval
= -EINVAL
;
264 if (get_user(new_options
, p
))
267 if (new_options
& WDIOS_DISABLECARD
) {
272 if (new_options
& WDIOS_ENABLECARD
) {
279 case WDIOC_KEEPALIVE
:
282 case WDIOC_SETTIMEOUT
:
286 if (get_user(new_timeout
, p
))
289 /* arbitrary upper limit */
290 if (new_timeout
< 1 || new_timeout
> 3600)
293 timeout
= new_timeout
;
297 case WDIOC_GETTIMEOUT
:
298 return put_user(timeout
, p
);
304 static const struct file_operations wdt_fops
= {
305 .owner
= THIS_MODULE
,
309 .release
= fop_close
,
310 .unlocked_ioctl
= fop_ioctl
,
313 static struct miscdevice wdt_miscdev
= {
314 .minor
= WATCHDOG_MINOR
,
320 * Notifier for system down
323 static int wdt_notify_sys(struct notifier_block
*this, unsigned long code
,
326 if (code
== SYS_DOWN
|| code
== SYS_HALT
)
332 * The WDT needs to learn about soft shutdowns in order to
333 * turn the timebomb registers off.
336 static struct notifier_block wdt_notifier
= {
337 .notifier_call
= wdt_notify_sys
,
340 static void __exit
w83877f_wdt_unload(void)
345 misc_deregister(&wdt_miscdev
);
347 unregister_reboot_notifier(&wdt_notifier
);
348 release_region(WDT_PING
, 1);
349 release_region(ENABLE_W83877F_PORT
, 2);
352 static int __init
w83877f_wdt_init(void)
356 if (timeout
< 1 || timeout
> 3600) { /* arbitrary upper limit */
357 timeout
= WATCHDOG_TIMEOUT
;
358 pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
362 if (!request_region(ENABLE_W83877F_PORT
, 2, "W83877F WDT")) {
363 pr_err("I/O address 0x%04x already in use\n",
364 ENABLE_W83877F_PORT
);
369 if (!request_region(WDT_PING
, 1, "W8387FF WDT")) {
370 pr_err("I/O address 0x%04x already in use\n", WDT_PING
);
372 goto err_out_region1
;
375 rc
= register_reboot_notifier(&wdt_notifier
);
377 pr_err("cannot register reboot notifier (err=%d)\n", rc
);
378 goto err_out_region2
;
381 rc
= misc_register(&wdt_miscdev
);
383 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
384 wdt_miscdev
.minor
, rc
);
388 pr_info("WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n",
394 unregister_reboot_notifier(&wdt_notifier
);
396 release_region(WDT_PING
, 1);
398 release_region(ENABLE_W83877F_PORT
, 2);
403 module_init(w83877f_wdt_init
);
404 module_exit(w83877f_wdt_unload
);
406 MODULE_AUTHOR("Scott and Bill Jennings");
407 MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip");
408 MODULE_LICENSE("GPL");