2 * NANO7240 SBC Watchdog device driver
4 * Based on w83877f.c by Scott Jennings,
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation;
10 * Software distributed under the License is distributed on an "AS IS"
11 * basis, WITHOUT WARRANTY OF ANY KIND, either express or
12 * implied. See the License for the specific language governing
13 * rights and limitations under the License.
15 * (c) Copyright 2007 Gilles GIGAN <gilles.gigan@jcu.edu.au>
20 #include <linux/init.h>
21 #include <linux/ioport.h>
22 #include <linux/jiffies.h>
23 #include <linux/module.h>
24 #include <linux/moduleparam.h>
25 #include <linux/miscdevice.h>
26 #include <linux/notifier.h>
27 #include <linux/reboot.h>
28 #include <linux/types.h>
29 #include <linux/watchdog.h>
31 #include <linux/uaccess.h>
32 #include <asm/atomic.h>
33 #include <asm/system.h>
35 #define SBC7240_PREFIX "sbc7240_wdt: "
37 #define SBC7240_ENABLE_PORT 0x443
38 #define SBC7240_DISABLE_PORT 0x043
39 #define SBC7240_SET_TIMEOUT_PORT SBC7240_ENABLE_PORT
40 #define SBC7240_MAGIC_CHAR 'V'
42 #define SBC7240_TIMEOUT 30
43 #define SBC7240_MAX_TIMEOUT 255
44 static int timeout = SBC7240_TIMEOUT; /* in seconds */
45 module_param(timeout, int, 0);
46 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<="
47 __MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default="
48 __MODULE_STRING(SBC7240_TIMEOUT) ")");
50 static int nowayout = WATCHDOG_NOWAYOUT;
51 module_param(nowayout, int, 0);
52 MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file");
54 #define SBC7240_OPEN_STATUS_BIT 0
55 #define SBC7240_ENABLED_STATUS_BIT 1
56 #define SBC7240_EXPECT_CLOSE_STATUS_BIT 2
57 static unsigned long wdt_status;
63 static void wdt_disable(void)
65 /* disable the watchdog */
66 if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
67 inb_p(SBC7240_DISABLE_PORT);
68 printk(KERN_INFO SBC7240_PREFIX
69 "Watchdog timer is now disabled.\n");
73 static void wdt_enable(void)
75 /* enable the watchdog */
76 if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
77 inb_p(SBC7240_ENABLE_PORT);
78 printk(KERN_INFO SBC7240_PREFIX
79 "Watchdog timer is now enabled.\n");
83 static int wdt_set_timeout(int t)
85 if (t < 1 || t > SBC7240_MAX_TIMEOUT) {
86 printk(KERN_ERR SBC7240_PREFIX
87 "timeout value must be 1<=x<=%d\n",
92 outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT);
94 printk(KERN_INFO SBC7240_PREFIX "timeout set to %d seconds\n", t);
99 static inline void wdt_keepalive(void)
101 if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status))
102 inb_p(SBC7240_ENABLE_PORT);
106 * /dev/watchdog handling
108 static ssize_t fop_write(struct file *file, const char __user *buf,
109 size_t count, loff_t *ppos)
116 clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
119 /* is there a magic char ? */
120 for (i = 0; i != count; i++) {
121 if (get_user(c, buf + i))
123 if (c == SBC7240_MAGIC_CHAR) {
124 set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
137 static int fop_open(struct inode *inode, struct file *file)
139 if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status))
144 return nonseekable_open(inode, file);
147 static int fop_close(struct inode *inode, struct file *file)
149 if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status)
153 printk(KERN_CRIT SBC7240_PREFIX
154 "Unexpected close, not stopping watchdog!\n");
158 clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status);
162 static const struct watchdog_info ident = {
163 .options = WDIOF_KEEPALIVEPING|
166 .firmware_version = 1,
167 .identity = "SBC7240",
171 static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
174 case WDIOC_GETSUPPORT:
175 return copy_to_user((void __user *)arg, &ident, sizeof(ident))
177 case WDIOC_GETSTATUS:
178 case WDIOC_GETBOOTSTATUS:
179 return put_user(0, (int __user *)arg);
180 case WDIOC_SETOPTIONS:
183 int retval = -EINVAL;
185 if (get_user(options, (int __user *)arg))
188 if (options & WDIOS_DISABLECARD) {
193 if (options & WDIOS_ENABLECARD) {
200 case WDIOC_KEEPALIVE:
203 case WDIOC_SETTIMEOUT:
207 if (get_user(new_timeout, (int __user *)arg))
210 if (wdt_set_timeout(new_timeout))
215 case WDIOC_GETTIMEOUT:
216 return put_user(timeout, (int __user *)arg);
222 static const struct file_operations wdt_fops = {
223 .owner = THIS_MODULE,
227 .release = fop_close,
228 .unlocked_ioctl = fop_ioctl,
231 static struct miscdevice wdt_miscdev = {
232 .minor = WATCHDOG_MINOR,
238 * Notifier for system down
241 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
244 if (code == SYS_DOWN || code == SYS_HALT)
249 static struct notifier_block wdt_notifier = {
250 .notifier_call = wdt_notify_sys,
253 static void __exit sbc7240_wdt_unload(void)
255 printk(KERN_INFO SBC7240_PREFIX "Removing watchdog\n");
256 misc_deregister(&wdt_miscdev);
258 unregister_reboot_notifier(&wdt_notifier);
259 release_region(SBC7240_ENABLE_PORT, 1);
262 static int __init sbc7240_wdt_init(void)
266 if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) {
267 printk(KERN_ERR SBC7240_PREFIX
268 "I/O address 0x%04x already in use\n",
269 SBC7240_ENABLE_PORT);
274 /* The IO port 0x043 used to disable the watchdog
275 * is already claimed by the system timer, so we
276 * cant request_region() it ...*/
278 if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) {
279 timeout = SBC7240_TIMEOUT;
280 printk(KERN_INFO SBC7240_PREFIX
281 "timeout value must be 1<=x<=%d, using %d\n",
282 SBC7240_MAX_TIMEOUT, timeout);
284 wdt_set_timeout(timeout);
287 rc = register_reboot_notifier(&wdt_notifier);
289 printk(KERN_ERR SBC7240_PREFIX
290 "cannot register reboot notifier (err=%d)\n", rc);
294 rc = misc_register(&wdt_miscdev);
296 printk(KERN_ERR SBC7240_PREFIX
297 "cannot register miscdev on minor=%d (err=%d)\n",
298 wdt_miscdev.minor, rc);
299 goto err_out_reboot_notifier;
302 printk(KERN_INFO SBC7240_PREFIX
303 "Watchdog driver for SBC7240 initialised (nowayout=%d)\n",
308 err_out_reboot_notifier:
309 unregister_reboot_notifier(&wdt_notifier);
311 release_region(SBC7240_ENABLE_PORT, 1);
316 module_init(sbc7240_wdt_init);
317 module_exit(sbc7240_wdt_unload);
319 MODULE_AUTHOR("Gilles Gigan");
320 MODULE_DESCRIPTION("Watchdog device driver for single board"
321 " computers EPIC Nano 7240 from iEi");
322 MODULE_LICENSE("GPL");
323 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);