2 * IB700 Single Board Computer WDT driver
4 * (c) Copyright 2001 Charles Howes <chowes@vsol.net>
6 * Based on advantechwdt.c which is based on acquirewdt.c which
9 * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
11 * Based on acquirewdt.c which is based on wdt.c.
12 * Original copyright messages:
14 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
15 * All Rights Reserved.
17 * This program is free software; you can redistribute it and/or
18 * modify it under the terms of the GNU General Public License
19 * as published by the Free Software Foundation; either version
20 * 2 of the License, or (at your option) any later version.
22 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
23 * warranty for any of this software. This material is provided
24 * "AS-IS" and at no charge.
26 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
28 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
29 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
30 * Added timeout module option to override default
34 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
36 #include <linux/module.h>
37 #include <linux/types.h>
38 #include <linux/miscdevice.h>
39 #include <linux/watchdog.h>
40 #include <linux/ioport.h>
42 #include <linux/init.h>
43 #include <linux/spinlock.h>
44 #include <linux/moduleparam.h>
45 #include <linux/platform_device.h>
47 #include <linux/uaccess.h>
49 #include <asm/system.h>
51 static struct platform_device *ibwdt_platform_device;
52 static unsigned long ibwdt_is_open;
53 static DEFINE_SPINLOCK(ibwdt_lock);
54 static char expect_close;
56 /* Module information */
57 #define DRV_NAME "ib700wdt"
61 * Watchdog Timer Configuration
63 * The function of the watchdog timer is to reset the system
64 * automatically and is defined at I/O port 0443H. To enable the
65 * watchdog timer and allow the system to reset, write I/O port 0443H.
66 * To disable the timer, write I/O port 0441H for the system to stop the
67 * watchdog function. The timer has a tolerance of 20% for its
70 * The following describes how the timer should be programmed.
73 * MOV AX,000FH (Choose the values from 0 to F)
78 * MOV AX,000FH (Any value is fine.)
82 * Watchdog timer control table:
83 * Level Value Time/sec | Level Value Time/sec
95 #define WDT_STOP 0x441
96 #define WDT_START 0x443
99 #define WATCHDOG_TIMEOUT 30 /* 30 seconds +/- 20% */
100 static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
101 module_param(timeout, int, 0);
102 MODULE_PARM_DESC(timeout,
103 "Watchdog timeout in seconds. 0<= timeout <=30, default="
104 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
106 static bool nowayout = WATCHDOG_NOWAYOUT;
107 module_param(nowayout, bool, 0);
108 MODULE_PARM_DESC(nowayout,
109 "Watchdog cannot be stopped once started (default="
110 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
114 * Watchdog Operations
117 static void ibwdt_ping(void)
119 int wd_margin = 15 - ((timeout + 1) / 2);
121 spin_lock(&ibwdt_lock);
123 /* Write a watchdog value */
124 outb_p(wd_margin, WDT_START);
126 spin_unlock(&ibwdt_lock);
129 static void ibwdt_disable(void)
131 spin_lock(&ibwdt_lock);
133 spin_unlock(&ibwdt_lock);
136 static int ibwdt_set_heartbeat(int t)
146 * /dev/watchdog handling
149 static ssize_t ibwdt_write(struct file *file, const char __user *buf,
150 size_t count, loff_t *ppos)
156 /* In case it was set long ago */
159 for (i = 0; i != count; i++) {
161 if (get_user(c, buf + i))
172 static long ibwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
175 void __user *argp = (void __user *)arg;
176 int __user *p = argp;
178 static const struct watchdog_info ident = {
179 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
181 .firmware_version = 1,
182 .identity = "IB700 WDT",
186 case WDIOC_GETSUPPORT:
187 if (copy_to_user(argp, &ident, sizeof(ident)))
191 case WDIOC_GETSTATUS:
192 case WDIOC_GETBOOTSTATUS:
193 return put_user(0, p);
195 case WDIOC_SETOPTIONS:
197 int options, retval = -EINVAL;
199 if (get_user(options, p))
202 if (options & WDIOS_DISABLECARD) {
206 if (options & WDIOS_ENABLECARD) {
212 case WDIOC_KEEPALIVE:
216 case WDIOC_SETTIMEOUT:
217 if (get_user(new_margin, p))
219 if (ibwdt_set_heartbeat(new_margin))
224 case WDIOC_GETTIMEOUT:
225 return put_user(timeout, p);
233 static int ibwdt_open(struct inode *inode, struct file *file)
235 if (test_and_set_bit(0, &ibwdt_is_open))
238 __module_get(THIS_MODULE);
242 return nonseekable_open(inode, file);
245 static int ibwdt_close(struct inode *inode, struct file *file)
247 if (expect_close == 42) {
250 pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");
253 clear_bit(0, &ibwdt_is_open);
262 static const struct file_operations ibwdt_fops = {
263 .owner = THIS_MODULE,
265 .write = ibwdt_write,
266 .unlocked_ioctl = ibwdt_ioctl,
268 .release = ibwdt_close,
271 static struct miscdevice ibwdt_miscdev = {
272 .minor = WATCHDOG_MINOR,
278 * Init & exit routines
281 static int __devinit ibwdt_probe(struct platform_device *dev)
285 #if WDT_START != WDT_STOP
286 if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
287 pr_err("STOP method I/O %X is not available\n", WDT_STOP);
293 if (!request_region(WDT_START, 1, "IB700 WDT")) {
294 pr_err("START method I/O %X is not available\n", WDT_START);
299 /* Check that the heartbeat value is within it's range ;
300 * if not reset to the default */
301 if (ibwdt_set_heartbeat(timeout)) {
302 ibwdt_set_heartbeat(WATCHDOG_TIMEOUT);
303 pr_info("timeout value must be 0<=x<=30, using %d\n", timeout);
306 res = misc_register(&ibwdt_miscdev);
308 pr_err("failed to register misc device\n");
314 release_region(WDT_START, 1);
316 #if WDT_START != WDT_STOP
317 release_region(WDT_STOP, 1);
323 static int __devexit ibwdt_remove(struct platform_device *dev)
325 misc_deregister(&ibwdt_miscdev);
326 release_region(WDT_START, 1);
327 #if WDT_START != WDT_STOP
328 release_region(WDT_STOP, 1);
333 static void ibwdt_shutdown(struct platform_device *dev)
335 /* Turn the WDT off if we have a soft shutdown */
339 static struct platform_driver ibwdt_driver = {
340 .probe = ibwdt_probe,
341 .remove = __devexit_p(ibwdt_remove),
342 .shutdown = ibwdt_shutdown,
344 .owner = THIS_MODULE,
349 static int __init ibwdt_init(void)
353 pr_info("WDT driver for IB700 single board computer initialising\n");
355 err = platform_driver_register(&ibwdt_driver);
359 ibwdt_platform_device = platform_device_register_simple(DRV_NAME,
361 if (IS_ERR(ibwdt_platform_device)) {
362 err = PTR_ERR(ibwdt_platform_device);
363 goto unreg_platform_driver;
368 unreg_platform_driver:
369 platform_driver_unregister(&ibwdt_driver);
373 static void __exit ibwdt_exit(void)
375 platform_device_unregister(ibwdt_platform_device);
376 platform_driver_unregister(&ibwdt_driver);
377 pr_info("Watchdog Module Unloaded\n");
380 module_init(ibwdt_init);
381 module_exit(ibwdt_exit);
383 MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
384 MODULE_DESCRIPTION("IB700 SBC watchdog driver");
385 MODULE_LICENSE("GPL");
386 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
388 /* end of ib700wdt.c */