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1da177e4 LT |
1 | /* |
2 | * IB700 Single Board Computer WDT driver | |
3 | * | |
4 | * (c) Copyright 2001 Charles Howes <chowes@vsol.net> | |
5 | * | |
6 | * Based on advantechwdt.c which is based on acquirewdt.c which | |
7 | * is based on wdt.c. | |
8 | * | |
9 | * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl> | |
10 | * | |
11 | * Based on acquirewdt.c which is based on wdt.c. | |
12 | * Original copyright messages: | |
13 | * | |
14 | * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved. | |
15 | * http://www.redhat.com | |
16 | * | |
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. | |
21 | * | |
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. | |
25 | * | |
26 | * (c) Copyright 1995 Alan Cox <alan@redhat.com> | |
27 | * | |
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 | |
31 | * | |
32 | */ | |
33 | ||
34 | #include <linux/config.h> | |
35 | #include <linux/module.h> | |
36 | #include <linux/types.h> | |
37 | #include <linux/miscdevice.h> | |
38 | #include <linux/watchdog.h> | |
39 | #include <linux/ioport.h> | |
40 | #include <linux/notifier.h> | |
41 | #include <linux/fs.h> | |
42 | #include <linux/reboot.h> | |
43 | #include <linux/init.h> | |
44 | #include <linux/spinlock.h> | |
45 | #include <linux/moduleparam.h> | |
46 | ||
47 | #include <asm/io.h> | |
48 | #include <asm/uaccess.h> | |
49 | #include <asm/system.h> | |
50 | ||
51 | static unsigned long ibwdt_is_open; | |
52 | static spinlock_t ibwdt_lock; | |
53 | static char expect_close; | |
54 | ||
55 | #define PFX "ib700wdt: " | |
56 | ||
57 | /* | |
58 | * | |
59 | * Watchdog Timer Configuration | |
60 | * | |
61 | * The function of the watchdog timer is to reset the system | |
62 | * automatically and is defined at I/O port 0443H. To enable the | |
63 | * watchdog timer and allow the system to reset, write I/O port 0443H. | |
64 | * To disable the timer, write I/O port 0441H for the system to stop the | |
65 | * watchdog function. The timer has a tolerance of 20% for its | |
66 | * intervals. | |
67 | * | |
68 | * The following describes how the timer should be programmed. | |
69 | * | |
70 | * Enabling Watchdog: | |
71 | * MOV AX,000FH (Choose the values from 0 to F) | |
72 | * MOV DX,0443H | |
73 | * OUT DX,AX | |
74 | * | |
75 | * Disabling Watchdog: | |
76 | * MOV AX,000FH (Any value is fine.) | |
77 | * MOV DX,0441H | |
78 | * OUT DX,AX | |
79 | * | |
80 | * Watchdog timer control table: | |
81 | * Level Value Time/sec | Level Value Time/sec | |
82 | * 1 F 0 | 9 7 16 | |
83 | * 2 E 2 | 10 6 18 | |
84 | * 3 D 4 | 11 5 20 | |
85 | * 4 C 6 | 12 4 22 | |
86 | * 5 B 8 | 13 3 24 | |
87 | * 6 A 10 | 14 2 26 | |
88 | * 7 9 12 | 15 1 28 | |
89 | * 8 8 14 | 16 0 30 | |
90 | * | |
91 | */ | |
92 | ||
93 | static int wd_times[] = { | |
94 | 30, /* 0x0 */ | |
95 | 28, /* 0x1 */ | |
96 | 26, /* 0x2 */ | |
97 | 24, /* 0x3 */ | |
98 | 22, /* 0x4 */ | |
99 | 20, /* 0x5 */ | |
100 | 18, /* 0x6 */ | |
101 | 16, /* 0x7 */ | |
102 | 14, /* 0x8 */ | |
103 | 12, /* 0x9 */ | |
104 | 10, /* 0xA */ | |
105 | 8, /* 0xB */ | |
106 | 6, /* 0xC */ | |
107 | 4, /* 0xD */ | |
108 | 2, /* 0xE */ | |
109 | 0, /* 0xF */ | |
110 | }; | |
111 | ||
112 | #define WDT_STOP 0x441 | |
113 | #define WDT_START 0x443 | |
114 | ||
115 | /* Default timeout */ | |
116 | #define WD_TIMO 0 /* 30 seconds +/- 20%, from table */ | |
117 | ||
118 | static int wd_margin = WD_TIMO; | |
119 | ||
4bfdf378 | 120 | static int nowayout = WATCHDOG_NOWAYOUT; |
1da177e4 LT |
121 | module_param(nowayout, int, 0); |
122 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); | |
123 | ||
124 | ||
125 | /* | |
126 | * Kernel methods. | |
127 | */ | |
128 | ||
129 | static void | |
130 | ibwdt_ping(void) | |
131 | { | |
132 | /* Write a watchdog value */ | |
133 | outb_p(wd_margin, WDT_START); | |
134 | } | |
135 | ||
136 | static ssize_t | |
137 | ibwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
138 | { | |
139 | if (count) { | |
140 | if (!nowayout) { | |
141 | size_t i; | |
142 | ||
143 | /* In case it was set long ago */ | |
144 | expect_close = 0; | |
145 | ||
146 | for (i = 0; i != count; i++) { | |
147 | char c; | |
148 | if (get_user(c, buf + i)) | |
149 | return -EFAULT; | |
150 | if (c == 'V') | |
151 | expect_close = 42; | |
152 | } | |
153 | } | |
154 | ibwdt_ping(); | |
155 | } | |
156 | return count; | |
157 | } | |
158 | ||
159 | static int | |
160 | ibwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, | |
161 | unsigned long arg) | |
162 | { | |
163 | int i, new_margin; | |
164 | void __user *argp = (void __user *)arg; | |
165 | int __user *p = argp; | |
166 | ||
167 | static struct watchdog_info ident = { | |
168 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, | |
169 | .firmware_version = 1, | |
170 | .identity = "IB700 WDT", | |
171 | }; | |
172 | ||
173 | switch (cmd) { | |
174 | case WDIOC_GETSUPPORT: | |
175 | if (copy_to_user(argp, &ident, sizeof(ident))) | |
176 | return -EFAULT; | |
177 | break; | |
178 | ||
179 | case WDIOC_GETSTATUS: | |
180 | return put_user(0, p); | |
181 | ||
182 | case WDIOC_KEEPALIVE: | |
183 | ibwdt_ping(); | |
184 | break; | |
185 | ||
186 | case WDIOC_SETTIMEOUT: | |
187 | if (get_user(new_margin, p)) | |
188 | return -EFAULT; | |
189 | if ((new_margin < 0) || (new_margin > 30)) | |
190 | return -EINVAL; | |
191 | for (i = 0x0F; i > -1; i--) | |
192 | if (wd_times[i] > new_margin) | |
193 | break; | |
194 | wd_margin = i; | |
195 | ibwdt_ping(); | |
196 | /* Fall */ | |
197 | ||
198 | case WDIOC_GETTIMEOUT: | |
199 | return put_user(wd_times[wd_margin], p); | |
200 | break; | |
201 | ||
202 | default: | |
203 | return -ENOIOCTLCMD; | |
204 | } | |
205 | return 0; | |
206 | } | |
207 | ||
208 | static int | |
209 | ibwdt_open(struct inode *inode, struct file *file) | |
210 | { | |
211 | spin_lock(&ibwdt_lock); | |
212 | if (test_and_set_bit(0, &ibwdt_is_open)) { | |
213 | spin_unlock(&ibwdt_lock); | |
214 | return -EBUSY; | |
215 | } | |
216 | if (nowayout) | |
217 | __module_get(THIS_MODULE); | |
218 | ||
219 | /* Activate */ | |
220 | ibwdt_ping(); | |
221 | spin_unlock(&ibwdt_lock); | |
222 | return nonseekable_open(inode, file); | |
223 | } | |
224 | ||
225 | static int | |
226 | ibwdt_close(struct inode *inode, struct file *file) | |
227 | { | |
228 | spin_lock(&ibwdt_lock); | |
229 | if (expect_close == 42) | |
230 | outb_p(0, WDT_STOP); | |
231 | else | |
232 | printk(KERN_CRIT PFX "WDT device closed unexpectedly. WDT will not stop!\n"); | |
233 | ||
234 | clear_bit(0, &ibwdt_is_open); | |
235 | expect_close = 0; | |
236 | spin_unlock(&ibwdt_lock); | |
237 | return 0; | |
238 | } | |
239 | ||
240 | /* | |
241 | * Notifier for system down | |
242 | */ | |
243 | ||
244 | static int | |
245 | ibwdt_notify_sys(struct notifier_block *this, unsigned long code, | |
246 | void *unused) | |
247 | { | |
248 | if (code == SYS_DOWN || code == SYS_HALT) { | |
249 | /* Turn the WDT off */ | |
250 | outb_p(0, WDT_STOP); | |
251 | } | |
252 | return NOTIFY_DONE; | |
253 | } | |
254 | ||
255 | /* | |
256 | * Kernel Interfaces | |
257 | */ | |
258 | ||
259 | static struct file_operations ibwdt_fops = { | |
260 | .owner = THIS_MODULE, | |
261 | .llseek = no_llseek, | |
262 | .write = ibwdt_write, | |
263 | .ioctl = ibwdt_ioctl, | |
264 | .open = ibwdt_open, | |
265 | .release = ibwdt_close, | |
266 | }; | |
267 | ||
268 | static struct miscdevice ibwdt_miscdev = { | |
269 | .minor = WATCHDOG_MINOR, | |
270 | .name = "watchdog", | |
271 | .fops = &ibwdt_fops, | |
272 | }; | |
273 | ||
274 | /* | |
275 | * The WDT needs to learn about soft shutdowns in order to | |
276 | * turn the timebomb registers off. | |
277 | */ | |
278 | ||
279 | static struct notifier_block ibwdt_notifier = { | |
280 | .notifier_call = ibwdt_notify_sys, | |
281 | }; | |
282 | ||
283 | static int __init ibwdt_init(void) | |
284 | { | |
285 | int res; | |
286 | ||
287 | printk(KERN_INFO PFX "WDT driver for IB700 single board computer initialising.\n"); | |
288 | ||
289 | spin_lock_init(&ibwdt_lock); | |
290 | res = misc_register(&ibwdt_miscdev); | |
291 | if (res) { | |
292 | printk (KERN_ERR PFX "failed to register misc device\n"); | |
293 | goto out_nomisc; | |
294 | } | |
295 | ||
296 | #if WDT_START != WDT_STOP | |
297 | if (!request_region(WDT_STOP, 1, "IB700 WDT")) { | |
298 | printk (KERN_ERR PFX "STOP method I/O %X is not available.\n", WDT_STOP); | |
299 | res = -EIO; | |
300 | goto out_nostopreg; | |
301 | } | |
302 | #endif | |
303 | ||
304 | if (!request_region(WDT_START, 1, "IB700 WDT")) { | |
305 | printk (KERN_ERR PFX "START method I/O %X is not available.\n", WDT_START); | |
306 | res = -EIO; | |
307 | goto out_nostartreg; | |
308 | } | |
309 | res = register_reboot_notifier(&ibwdt_notifier); | |
310 | if (res) { | |
311 | printk (KERN_ERR PFX "Failed to register reboot notifier.\n"); | |
312 | goto out_noreboot; | |
313 | } | |
314 | return 0; | |
315 | ||
316 | out_noreboot: | |
317 | release_region(WDT_START, 1); | |
318 | out_nostartreg: | |
319 | #if WDT_START != WDT_STOP | |
320 | release_region(WDT_STOP, 1); | |
321 | #endif | |
322 | out_nostopreg: | |
323 | misc_deregister(&ibwdt_miscdev); | |
324 | out_nomisc: | |
325 | return res; | |
326 | } | |
327 | ||
328 | static void __exit | |
329 | ibwdt_exit(void) | |
330 | { | |
331 | misc_deregister(&ibwdt_miscdev); | |
332 | unregister_reboot_notifier(&ibwdt_notifier); | |
333 | #if WDT_START != WDT_STOP | |
334 | release_region(WDT_STOP,1); | |
335 | #endif | |
336 | release_region(WDT_START,1); | |
337 | } | |
338 | ||
339 | module_init(ibwdt_init); | |
340 | module_exit(ibwdt_exit); | |
341 | ||
342 | MODULE_AUTHOR("Charles Howes <chowes@vsol.net>"); | |
343 | MODULE_DESCRIPTION("IB700 SBC watchdog driver"); | |
344 | MODULE_LICENSE("GPL"); | |
345 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
346 | ||
347 | /* end of ib700wdt.c */ |