2 * ICP Wafer 5823 Single Board Computer WDT driver
3 * http://www.icpamerica.com/wafer_5823.php
4 * May also work on other similar models
6 * (c) Copyright 2002 Justin Cormack <justin@street-vision.com>
10 * Based on advantechwdt.c which is based on wdt.c.
11 * Original copyright messages:
13 * (c) Copyright 1996-1997 Alan Cox <alan@redhat.com>, All Rights Reserved.
14 * http://www.redhat.com
16 * This program is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU General Public License
18 * as published by the Free Software Foundation; either version
19 * 2 of the License, or (at your option) any later version.
21 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
22 * warranty for any of this software. This material is provided
23 * "AS-IS" and at no charge.
25 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
29 #include <linux/module.h>
30 #include <linux/moduleparam.h>
31 #include <linux/miscdevice.h>
32 #include <linux/watchdog.h>
34 #include <linux/ioport.h>
35 #include <linux/notifier.h>
36 #include <linux/reboot.h>
37 #include <linux/init.h>
38 #include <linux/spinlock.h>
40 #include <asm/uaccess.h>
42 #define WATCHDOG_NAME "Wafer 5823 WDT"
43 #define PFX WATCHDOG_NAME ": "
44 #define WD_TIMO 60 /* 60 sec default timeout */
46 static unsigned long wafwdt_is_open
;
47 static char expect_close
;
48 static spinlock_t wafwdt_lock
;
51 * You must set these - there is no sane way to probe for this board.
53 * To enable, write the timeout value in seconds (1 to 255) to I/O
54 * port WDT_START, then read the port to start the watchdog. To pat
55 * the dog, read port WDT_STOP to stop the timer, then read WDT_START
56 * to restart it again.
59 static int wdt_stop
= 0x843;
60 static int wdt_start
= 0x443;
62 static int timeout
= WD_TIMO
; /* in seconds */
63 module_param(timeout
, int, 0);
64 MODULE_PARM_DESC(timeout
, "Watchdog timeout in seconds. 1<= timeout <=255, default=" __MODULE_STRING(WD_TIMO
) ".");
66 static int nowayout
= WATCHDOG_NOWAYOUT
;
67 module_param(nowayout
, int, 0);
68 MODULE_PARM_DESC(nowayout
, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT
) ")");
70 static void wafwdt_ping(void)
73 spin_lock(&wafwdt_lock
);
76 spin_unlock(&wafwdt_lock
);
79 static void wafwdt_start(void)
81 /* start up watchdog */
82 outb_p(timeout
, wdt_start
);
93 static ssize_t
wafwdt_write(struct file
*file
, const char __user
*buf
, size_t count
, loff_t
* ppos
)
95 /* See if we got the magic character 'V' and reload the timer */
100 /* In case it was set long ago */
103 /* scan to see whether or not we got the magic character */
104 for (i
= 0; i
!= count
; i
++) {
106 if (get_user(c
, buf
+ i
))
112 /* Well, anyhow someone wrote to us, we should return that favour */
118 static int wafwdt_ioctl(struct inode
*inode
, struct file
*file
, unsigned int cmd
,
122 void __user
*argp
= (void __user
*)arg
;
123 int __user
*p
= argp
;
124 static struct watchdog_info ident
= {
125 .options
= WDIOF_KEEPALIVEPING
| WDIOF_SETTIMEOUT
| WDIOF_MAGICCLOSE
,
126 .firmware_version
= 1,
127 .identity
= "Wafer 5823 WDT",
131 case WDIOC_GETSUPPORT
:
132 if (copy_to_user(argp
, &ident
, sizeof (ident
)))
136 case WDIOC_GETSTATUS
:
137 case WDIOC_GETBOOTSTATUS
:
138 return put_user(0, p
);
140 case WDIOC_KEEPALIVE
:
144 case WDIOC_SETTIMEOUT
:
145 if (get_user(new_timeout
, p
))
147 if ((new_timeout
< 1) || (new_timeout
> 255))
149 timeout
= new_timeout
;
153 case WDIOC_GETTIMEOUT
:
154 return put_user(timeout
, p
);
156 case WDIOC_SETOPTIONS
:
158 int options
, retval
= -EINVAL
;
160 if (get_user(options
, p
))
163 if (options
& WDIOS_DISABLECARD
) {
168 if (options
& WDIOS_ENABLECARD
) {
182 static int wafwdt_open(struct inode
*inode
, struct file
*file
)
184 if (test_and_set_bit(0, &wafwdt_is_open
))
191 return nonseekable_open(inode
, file
);
195 wafwdt_close(struct inode
*inode
, struct file
*file
)
197 if (expect_close
== 42) {
200 printk(KERN_CRIT PFX
"WDT device closed unexpectedly. WDT will not stop!\n");
203 clear_bit(0, &wafwdt_is_open
);
209 * Notifier for system down
212 static int wafwdt_notify_sys(struct notifier_block
*this, unsigned long code
, void *unused
)
214 if (code
== SYS_DOWN
|| code
== SYS_HALT
) {
215 /* Turn the WDT off */
225 static const struct file_operations wafwdt_fops
= {
226 .owner
= THIS_MODULE
,
228 .write
= wafwdt_write
,
229 .ioctl
= wafwdt_ioctl
,
231 .release
= wafwdt_close
,
234 static struct miscdevice wafwdt_miscdev
= {
235 .minor
= WATCHDOG_MINOR
,
237 .fops
= &wafwdt_fops
,
241 * The WDT needs to learn about soft shutdowns in order to
242 * turn the timebomb registers off.
245 static struct notifier_block wafwdt_notifier
= {
246 .notifier_call
= wafwdt_notify_sys
,
249 static int __init
wafwdt_init(void)
253 printk(KERN_INFO
"WDT driver for Wafer 5823 single board computer initialising.\n");
255 spin_lock_init(&wafwdt_lock
);
257 if (timeout
< 1 || timeout
> 255) {
259 printk (KERN_INFO PFX
"timeout value must be 1<=x<=255, using %d\n",
263 if (wdt_stop
!= wdt_start
) {
264 if(!request_region(wdt_stop
, 1, "Wafer 5823 WDT")) {
265 printk (KERN_ERR PFX
"I/O address 0x%04x already in use\n",
272 if(!request_region(wdt_start
, 1, "Wafer 5823 WDT")) {
273 printk (KERN_ERR PFX
"I/O address 0x%04x already in use\n",
279 ret
= register_reboot_notifier(&wafwdt_notifier
);
281 printk (KERN_ERR PFX
"cannot register reboot notifier (err=%d)\n",
286 ret
= misc_register(&wafwdt_miscdev
);
288 printk (KERN_ERR PFX
"cannot register miscdev on minor=%d (err=%d)\n",
289 WATCHDOG_MINOR
, ret
);
293 printk (KERN_INFO PFX
"initialized. timeout=%d sec (nowayout=%d)\n",
298 unregister_reboot_notifier(&wafwdt_notifier
);
300 release_region(wdt_start
, 1);
302 if (wdt_stop
!= wdt_start
)
303 release_region(wdt_stop
, 1);
308 static void __exit
wafwdt_exit(void)
310 misc_deregister(&wafwdt_miscdev
);
311 unregister_reboot_notifier(&wafwdt_notifier
);
312 if(wdt_stop
!= wdt_start
)
313 release_region(wdt_stop
, 1);
314 release_region(wdt_start
, 1);
317 module_init(wafwdt_init
);
318 module_exit(wafwdt_exit
);
320 MODULE_AUTHOR("Justin Cormack");
321 MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
322 MODULE_LICENSE("GPL");
323 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR
);
325 /* end of wafer5823wdt.c */