1 /* drivers/char/watchdog/scx200_wdt.c
3 National Semiconductor SCx200 Watchdog support
5 Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
8 National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
9 (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>
11 This program is free software; you can redistribute it and/or
12 modify it under the terms of the GNU General Public License as
13 published by the Free Software Foundation; either version 2 of the
14 License, or (at your option) any later version.
16 The author(s) of this software shall not be held liable for damages
17 of any nature resulting due to the use of this software. This
18 software is provided AS-IS with no warranties. */
20 #include <linux/module.h>
21 #include <linux/moduleparam.h>
22 #include <linux/init.h>
23 #include <linux/miscdevice.h>
24 #include <linux/watchdog.h>
25 #include <linux/notifier.h>
26 #include <linux/reboot.h>
28 #include <linux/ioport.h>
29 #include <linux/scx200.h>
30 #include <linux/uaccess.h>
33 #define NAME "scx200_wdt"
35 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
36 MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver");
37 MODULE_LICENSE("GPL");
38 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
40 static int margin = 60; /* in seconds */
41 module_param(margin, int, 0);
42 MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
44 static int nowayout = WATCHDOG_NOWAYOUT;
45 module_param(nowayout, int, 0);
46 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
48 static u16 wdto_restart;
49 static char expect_close;
50 static unsigned long open_lock;
51 static DEFINE_SPINLOCK(scx_lock);
53 /* Bits of the WDCNFG register */
54 #define W_ENABLE 0x00fa /* Enable watchdog */
55 #define W_DISABLE 0x0000 /* Disable watchdog */
57 /* The scaling factor for the timer, this depends on the value of W_ENABLE */
58 #define W_SCALE (32768/1024)
60 static void scx200_wdt_ping(void)
63 outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO);
64 spin_unlock(&scx_lock);
67 static void scx200_wdt_update_margin(void)
69 printk(KERN_INFO NAME ": timer margin %d seconds\n", margin);
70 wdto_restart = margin * W_SCALE;
73 static void scx200_wdt_enable(void)
75 printk(KERN_DEBUG NAME ": enabling watchdog timer, wdto_restart = %d\n",
79 outw(0, scx200_cb_base + SCx200_WDT_WDTO);
80 outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
81 outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
82 spin_unlock(&scx_lock);
87 static void scx200_wdt_disable(void)
89 printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
92 outw(0, scx200_cb_base + SCx200_WDT_WDTO);
93 outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
94 outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
95 spin_unlock(&scx_lock);
98 static int scx200_wdt_open(struct inode *inode, struct file *file)
100 /* only allow one at a time */
101 if (test_and_set_bit(0, &open_lock))
105 return nonseekable_open(inode, file);
108 static int scx200_wdt_release(struct inode *inode, struct file *file)
110 if (expect_close != 42)
111 printk(KERN_WARNING NAME
112 ": watchdog device closed unexpectedly, "
113 "will not disable the watchdog timer\n");
115 scx200_wdt_disable();
117 clear_bit(0, &open_lock);
122 static int scx200_wdt_notify_sys(struct notifier_block *this,
123 unsigned long code, void *unused)
125 if (code == SYS_HALT || code == SYS_POWER_OFF)
127 scx200_wdt_disable();
132 static struct notifier_block scx200_wdt_notifier = {
133 .notifier_call = scx200_wdt_notify_sys,
136 static ssize_t scx200_wdt_write(struct file *file, const char __user *data,
137 size_t len, loff_t *ppos)
139 /* check for a magic close character */
146 for (i = 0; i < len; ++i) {
148 if (get_user(c, data + i))
160 static long scx200_wdt_ioctl(struct file *file, unsigned int cmd,
163 void __user *argp = (void __user *)arg;
164 int __user *p = argp;
165 static const struct watchdog_info ident = {
166 .identity = "NatSemi SCx200 Watchdog",
167 .firmware_version = 1,
168 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
173 case WDIOC_GETSUPPORT:
174 if (copy_to_user(argp, &ident, sizeof(ident)))
177 case WDIOC_GETSTATUS:
178 case WDIOC_GETBOOTSTATUS:
182 case WDIOC_KEEPALIVE:
185 case WDIOC_SETTIMEOUT:
186 if (get_user(new_margin, p))
191 scx200_wdt_update_margin();
193 case WDIOC_GETTIMEOUT:
194 if (put_user(margin, p))
202 static const struct file_operations scx200_wdt_fops = {
203 .owner = THIS_MODULE,
205 .write = scx200_wdt_write,
206 .unlocked_ioctl = scx200_wdt_ioctl,
207 .open = scx200_wdt_open,
208 .release = scx200_wdt_release,
211 static struct miscdevice scx200_wdt_miscdev = {
212 .minor = WATCHDOG_MINOR,
214 .fops = &scx200_wdt_fops,
217 static int __init scx200_wdt_init(void)
221 printk(KERN_DEBUG NAME ": NatSemi SCx200 Watchdog Driver\n");
223 /* check that we have found the configuration block */
224 if (!scx200_cb_present())
227 if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET,
229 "NatSemi SCx200 Watchdog")) {
230 printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
234 scx200_wdt_update_margin();
235 scx200_wdt_disable();
237 r = register_reboot_notifier(&scx200_wdt_notifier);
239 printk(KERN_ERR NAME ": unable to register reboot notifier");
240 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
245 r = misc_register(&scx200_wdt_miscdev);
247 unregister_reboot_notifier(&scx200_wdt_notifier);
248 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
256 static void __exit scx200_wdt_cleanup(void)
258 misc_deregister(&scx200_wdt_miscdev);
259 unregister_reboot_notifier(&scx200_wdt_notifier);
260 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
264 module_init(scx200_wdt_init);
265 module_exit(scx200_wdt_cleanup);
269 compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"