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1da177e4 LT |
1 | /* |
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 | |
5 | * | |
6 | * (c) Copyright 2002 Justin Cormack <justin@street-vision.com> | |
7 | * | |
8 | * Release 0.02 | |
9 | * | |
10 | * Based on advantechwdt.c which is based on wdt.c. | |
11 | * Original copyright messages: | |
12 | * | |
13 | * (c) Copyright 1996-1997 Alan Cox <alan@redhat.com>, All Rights Reserved. | |
14 | * http://www.redhat.com | |
15 | * | |
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. | |
20 | * | |
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. | |
24 | * | |
25 | * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> | |
26 | * | |
27 | */ | |
28 | ||
29 | #include <linux/module.h> | |
30 | #include <linux/moduleparam.h> | |
31 | #include <linux/miscdevice.h> | |
32 | #include <linux/watchdog.h> | |
33 | #include <linux/fs.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> | |
39 | #include <asm/io.h> | |
40 | #include <asm/uaccess.h> | |
41 | ||
42 | #define WATCHDOG_NAME "Wafer 5823 WDT" | |
43 | #define PFX WATCHDOG_NAME ": " | |
44 | #define WD_TIMO 60 /* 60 sec default timeout */ | |
45 | ||
46 | static unsigned long wafwdt_is_open; | |
47 | static char expect_close; | |
48 | static spinlock_t wafwdt_lock; | |
49 | ||
50 | /* | |
51 | * You must set these - there is no sane way to probe for this board. | |
52 | * | |
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. | |
57 | */ | |
58 | ||
59 | static int wdt_stop = 0x843; | |
60 | static int wdt_start = 0x443; | |
61 | ||
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) "."); | |
65 | ||
66 | #ifdef CONFIG_WATCHDOG_NOWAYOUT | |
67 | static int nowayout = 1; | |
68 | #else | |
69 | static int nowayout = 0; | |
70 | #endif | |
71 | ||
72 | module_param(nowayout, int, 0); | |
73 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); | |
74 | ||
75 | static void wafwdt_ping(void) | |
76 | { | |
77 | /* pat watchdog */ | |
78 | spin_lock(&wafwdt_lock); | |
79 | inb_p(wdt_stop); | |
80 | inb_p(wdt_start); | |
81 | spin_unlock(&wafwdt_lock); | |
82 | } | |
83 | ||
84 | static void wafwdt_start(void) | |
85 | { | |
86 | /* start up watchdog */ | |
87 | outb_p(timeout, wdt_start); | |
88 | inb_p(wdt_start); | |
89 | } | |
90 | ||
91 | static void | |
92 | wafwdt_stop(void) | |
93 | { | |
94 | /* stop watchdog */ | |
95 | inb_p(wdt_stop); | |
96 | } | |
97 | ||
98 | static ssize_t wafwdt_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos) | |
99 | { | |
100 | /* See if we got the magic character 'V' and reload the timer */ | |
101 | if (count) { | |
102 | if (!nowayout) { | |
103 | size_t i; | |
104 | ||
105 | /* In case it was set long ago */ | |
106 | expect_close = 0; | |
107 | ||
108 | /* scan to see whether or not we got the magic character */ | |
109 | for (i = 0; i != count; i++) { | |
110 | char c; | |
111 | if (get_user(c, buf + i)) | |
112 | return -EFAULT; | |
113 | if (c == 'V') | |
114 | expect_close = 42; | |
115 | } | |
116 | } | |
117 | /* Well, anyhow someone wrote to us, we should return that favour */ | |
118 | wafwdt_ping(); | |
119 | } | |
120 | return count; | |
121 | } | |
122 | ||
123 | static int wafwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, | |
124 | unsigned long arg) | |
125 | { | |
126 | int new_timeout; | |
127 | void __user *argp = (void __user *)arg; | |
128 | int __user *p = argp; | |
129 | static struct watchdog_info ident = { | |
130 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, | |
131 | .firmware_version = 1, | |
132 | .identity = "Wafer 5823 WDT", | |
133 | }; | |
134 | ||
135 | switch (cmd) { | |
136 | case WDIOC_GETSUPPORT: | |
137 | if (copy_to_user(argp, &ident, sizeof (ident))) | |
138 | return -EFAULT; | |
139 | break; | |
140 | ||
141 | case WDIOC_GETSTATUS: | |
142 | case WDIOC_GETBOOTSTATUS: | |
143 | return put_user(0, p); | |
144 | ||
145 | case WDIOC_KEEPALIVE: | |
146 | wafwdt_ping(); | |
147 | break; | |
148 | ||
149 | case WDIOC_SETTIMEOUT: | |
150 | if (get_user(new_timeout, p)) | |
151 | return -EFAULT; | |
152 | if ((new_timeout < 1) || (new_timeout > 255)) | |
153 | return -EINVAL; | |
154 | timeout = new_timeout; | |
155 | wafwdt_stop(); | |
156 | wafwdt_start(); | |
157 | /* Fall */ | |
158 | case WDIOC_GETTIMEOUT: | |
159 | return put_user(timeout, p); | |
160 | ||
161 | case WDIOC_SETOPTIONS: | |
162 | { | |
163 | int options, retval = -EINVAL; | |
164 | ||
165 | if (get_user(options, p)) | |
166 | return -EFAULT; | |
167 | ||
168 | if (options & WDIOS_DISABLECARD) { | |
169 | wafwdt_start(); | |
170 | retval = 0; | |
171 | } | |
172 | ||
173 | if (options & WDIOS_ENABLECARD) { | |
174 | wafwdt_stop(); | |
175 | retval = 0; | |
176 | } | |
177 | ||
178 | return retval; | |
179 | } | |
180 | ||
181 | default: | |
182 | return -ENOIOCTLCMD; | |
183 | } | |
184 | return 0; | |
185 | } | |
186 | ||
187 | static int wafwdt_open(struct inode *inode, struct file *file) | |
188 | { | |
189 | if (test_and_set_bit(0, &wafwdt_is_open)) | |
190 | return -EBUSY; | |
191 | ||
192 | /* | |
193 | * Activate | |
194 | */ | |
195 | wafwdt_start(); | |
196 | return nonseekable_open(inode, file); | |
197 | } | |
198 | ||
199 | static int | |
200 | wafwdt_close(struct inode *inode, struct file *file) | |
201 | { | |
202 | if (expect_close == 42) { | |
203 | wafwdt_stop(); | |
204 | } else { | |
205 | printk(KERN_CRIT PFX "WDT device closed unexpectedly. WDT will not stop!\n"); | |
206 | wafwdt_ping(); | |
207 | } | |
208 | clear_bit(0, &wafwdt_is_open); | |
209 | expect_close = 0; | |
210 | return 0; | |
211 | } | |
212 | ||
213 | /* | |
214 | * Notifier for system down | |
215 | */ | |
216 | ||
217 | static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) | |
218 | { | |
219 | if (code == SYS_DOWN || code == SYS_HALT) { | |
220 | /* Turn the WDT off */ | |
221 | wafwdt_stop(); | |
222 | } | |
223 | return NOTIFY_DONE; | |
224 | } | |
225 | ||
226 | /* | |
227 | * Kernel Interfaces | |
228 | */ | |
229 | ||
230 | static struct file_operations wafwdt_fops = { | |
231 | .owner = THIS_MODULE, | |
232 | .llseek = no_llseek, | |
233 | .write = wafwdt_write, | |
234 | .ioctl = wafwdt_ioctl, | |
235 | .open = wafwdt_open, | |
236 | .release = wafwdt_close, | |
237 | }; | |
238 | ||
239 | static struct miscdevice wafwdt_miscdev = { | |
240 | .minor = WATCHDOG_MINOR, | |
241 | .name = "watchdog", | |
242 | .fops = &wafwdt_fops, | |
243 | }; | |
244 | ||
245 | /* | |
246 | * The WDT needs to learn about soft shutdowns in order to | |
247 | * turn the timebomb registers off. | |
248 | */ | |
249 | ||
250 | static struct notifier_block wafwdt_notifier = { | |
251 | .notifier_call = wafwdt_notify_sys, | |
252 | }; | |
253 | ||
254 | static int __init wafwdt_init(void) | |
255 | { | |
256 | int ret; | |
257 | ||
258 | printk(KERN_INFO "WDT driver for Wafer 5823 single board computer initialising.\n"); | |
259 | ||
260 | spin_lock_init(&wafwdt_lock); | |
261 | ||
262 | if (timeout < 1 || timeout > 255) { | |
263 | timeout = WD_TIMO; | |
264 | printk (KERN_INFO PFX "timeout value must be 1<=x<=255, using %d\n", | |
265 | timeout); | |
266 | } | |
267 | ||
268 | if (wdt_stop != wdt_start) { | |
269 | if(!request_region(wdt_stop, 1, "Wafer 5823 WDT")) { | |
270 | printk (KERN_ERR PFX "I/O address 0x%04x already in use\n", | |
271 | wdt_stop); | |
272 | ret = -EIO; | |
273 | goto error; | |
274 | } | |
275 | } | |
276 | ||
277 | if(!request_region(wdt_start, 1, "Wafer 5823 WDT")) { | |
278 | printk (KERN_ERR PFX "I/O address 0x%04x already in use\n", | |
279 | wdt_start); | |
280 | ret = -EIO; | |
281 | goto error2; | |
282 | } | |
283 | ||
284 | ret = register_reboot_notifier(&wafwdt_notifier); | |
285 | if (ret != 0) { | |
286 | printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", | |
287 | ret); | |
288 | goto error3; | |
289 | } | |
290 | ||
291 | ret = misc_register(&wafwdt_miscdev); | |
292 | if (ret != 0) { | |
293 | printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", | |
294 | WATCHDOG_MINOR, ret); | |
295 | goto error4; | |
296 | } | |
297 | ||
298 | printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n", | |
299 | timeout, nowayout); | |
300 | ||
301 | return ret; | |
302 | error4: | |
303 | unregister_reboot_notifier(&wafwdt_notifier); | |
304 | error3: | |
305 | release_region(wdt_start, 1); | |
306 | error2: | |
307 | if (wdt_stop != wdt_start) | |
308 | release_region(wdt_stop, 1); | |
309 | error: | |
310 | return ret; | |
311 | } | |
312 | ||
313 | static void __exit wafwdt_exit(void) | |
314 | { | |
315 | misc_deregister(&wafwdt_miscdev); | |
316 | unregister_reboot_notifier(&wafwdt_notifier); | |
317 | if(wdt_stop != wdt_start) | |
318 | release_region(wdt_stop, 1); | |
319 | release_region(wdt_start, 1); | |
320 | } | |
321 | ||
322 | module_init(wafwdt_init); | |
323 | module_exit(wafwdt_exit); | |
324 | ||
325 | MODULE_AUTHOR("Justin Cormack"); | |
326 | MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver"); | |
327 | MODULE_LICENSE("GPL"); | |
328 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
329 | ||
330 | /* end of wafer5823wdt.c */ |