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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@lxorguk.ukuu.org.uk>, |
15 | * All Rights Reserved. |
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@lxorguk.ukuu.org.uk> |
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/module.h> |
35 | #include <linux/types.h> |
36 | #include <linux/miscdevice.h> |
37 | #include <linux/watchdog.h> |
38 | #include <linux/ioport.h> |
39 | #include <linux/fs.h> |
40 | #include <linux/init.h> |
41 | #include <linux/spinlock.h> |
42 | #include <linux/moduleparam.h> |
43 | #include <linux/platform_device.h> |
44 | #include <linux/io.h> |
45 | #include <linux/uaccess.h> |
46 | |
47 | #include <asm/system.h> |
48 | |
49 | static struct platform_device *ibwdt_platform_device; |
50 | static unsigned long ibwdt_is_open; |
51 | static DEFINE_SPINLOCK(ibwdt_lock); |
52 | static char expect_close; |
53 | |
54 | /* Module information */ |
55 | #define DRV_NAME "ib700wdt" |
56 | #define PFX DRV_NAME ": " |
57 | |
58 | /* |
59 | * |
60 | * Watchdog Timer Configuration |
61 | * |
62 | * The function of the watchdog timer is to reset the system |
63 | * automatically and is defined at I/O port 0443H. To enable the |
64 | * watchdog timer and allow the system to reset, write I/O port 0443H. |
65 | * To disable the timer, write I/O port 0441H for the system to stop the |
66 | * watchdog function. The timer has a tolerance of 20% for its |
67 | * intervals. |
68 | * |
69 | * The following describes how the timer should be programmed. |
70 | * |
71 | * Enabling Watchdog: |
72 | * MOV AX,000FH (Choose the values from 0 to F) |
73 | * MOV DX,0443H |
74 | * OUT DX,AX |
75 | * |
76 | * Disabling Watchdog: |
77 | * MOV AX,000FH (Any value is fine.) |
78 | * MOV DX,0441H |
79 | * OUT DX,AX |
80 | * |
81 | * Watchdog timer control table: |
82 | * Level Value Time/sec | Level Value Time/sec |
83 | * 1 F 0 | 9 7 16 |
84 | * 2 E 2 | 10 6 18 |
85 | * 3 D 4 | 11 5 20 |
86 | * 4 C 6 | 12 4 22 |
87 | * 5 B 8 | 13 3 24 |
88 | * 6 A 10 | 14 2 26 |
89 | * 7 9 12 | 15 1 28 |
90 | * 8 8 14 | 16 0 30 |
91 | * |
92 | */ |
93 | |
94 | #define WDT_STOP 0x441 |
95 | #define WDT_START 0x443 |
96 | |
97 | /* Default timeout */ |
98 | #define WATCHDOG_TIMEOUT 30 /* 30 seconds +/- 20% */ |
99 | static int timeout = WATCHDOG_TIMEOUT; /* in seconds */ |
100 | module_param(timeout, int, 0); |
101 | MODULE_PARM_DESC(timeout, |
102 | "Watchdog timeout in seconds. 0<= timeout <=30, default=" |
103 | __MODULE_STRING(WATCHDOG_TIMEOUT) "."); |
104 | |
105 | static int nowayout = WATCHDOG_NOWAYOUT; |
106 | module_param(nowayout, int, 0); |
107 | MODULE_PARM_DESC(nowayout, |
108 | "Watchdog cannot be stopped once started (default=" |
109 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
110 | |
111 | |
112 | /* |
113 | * Watchdog Operations |
114 | */ |
115 | |
116 | static void ibwdt_ping(void) |
117 | { |
118 | int wd_margin = 15 - ((timeout + 1) / 2); |
119 | |
120 | spin_lock(&ibwdt_lock); |
121 | |
122 | /* Write a watchdog value */ |
123 | outb_p(wd_margin, WDT_START); |
124 | |
125 | spin_unlock(&ibwdt_lock); |
126 | } |
127 | |
128 | static void ibwdt_disable(void) |
129 | { |
130 | spin_lock(&ibwdt_lock); |
131 | outb_p(0, WDT_STOP); |
132 | spin_unlock(&ibwdt_lock); |
133 | } |
134 | |
135 | static int ibwdt_set_heartbeat(int t) |
136 | { |
137 | if (t < 0 || t > 30) |
138 | return -EINVAL; |
139 | |
140 | timeout = t; |
141 | return 0; |
142 | } |
143 | |
144 | /* |
145 | * /dev/watchdog handling |
146 | */ |
147 | |
148 | static ssize_t ibwdt_write(struct file *file, const char __user *buf, |
149 | size_t count, loff_t *ppos) |
150 | { |
151 | if (count) { |
152 | if (!nowayout) { |
153 | size_t i; |
154 | |
155 | /* In case it was set long ago */ |
156 | expect_close = 0; |
157 | |
158 | for (i = 0; i != count; i++) { |
159 | char c; |
160 | if (get_user(c, buf + i)) |
161 | return -EFAULT; |
162 | if (c == 'V') |
163 | expect_close = 42; |
164 | } |
165 | } |
166 | ibwdt_ping(); |
167 | } |
168 | return count; |
169 | } |
170 | |
171 | static long ibwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
172 | { |
173 | int new_margin; |
174 | void __user *argp = (void __user *)arg; |
175 | int __user *p = argp; |
176 | |
177 | static const struct watchdog_info ident = { |
178 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
179 | | WDIOF_MAGICCLOSE, |
180 | .firmware_version = 1, |
181 | .identity = "IB700 WDT", |
182 | }; |
183 | |
184 | switch (cmd) { |
185 | case WDIOC_GETSUPPORT: |
186 | if (copy_to_user(argp, &ident, sizeof(ident))) |
187 | return -EFAULT; |
188 | break; |
189 | |
190 | case WDIOC_GETSTATUS: |
191 | case WDIOC_GETBOOTSTATUS: |
192 | return put_user(0, p); |
193 | |
194 | case WDIOC_SETOPTIONS: |
195 | { |
196 | int options, retval = -EINVAL; |
197 | |
198 | if (get_user(options, p)) |
199 | return -EFAULT; |
200 | |
201 | if (options & WDIOS_DISABLECARD) { |
202 | ibwdt_disable(); |
203 | retval = 0; |
204 | } |
205 | if (options & WDIOS_ENABLECARD) { |
206 | ibwdt_ping(); |
207 | retval = 0; |
208 | } |
209 | return retval; |
210 | } |
211 | case WDIOC_KEEPALIVE: |
212 | ibwdt_ping(); |
213 | break; |
214 | |
215 | case WDIOC_SETTIMEOUT: |
216 | if (get_user(new_margin, p)) |
217 | return -EFAULT; |
218 | if (ibwdt_set_heartbeat(new_margin)) |
219 | return -EINVAL; |
220 | ibwdt_ping(); |
221 | /* Fall */ |
222 | |
223 | case WDIOC_GETTIMEOUT: |
224 | return put_user(timeout, p); |
225 | |
226 | default: |
227 | return -ENOTTY; |
228 | } |
229 | return 0; |
230 | } |
231 | |
232 | static int ibwdt_open(struct inode *inode, struct file *file) |
233 | { |
234 | if (test_and_set_bit(0, &ibwdt_is_open)) |
235 | return -EBUSY; |
236 | if (nowayout) |
237 | __module_get(THIS_MODULE); |
238 | |
239 | /* Activate */ |
240 | ibwdt_ping(); |
241 | return nonseekable_open(inode, file); |
242 | } |
243 | |
244 | static int ibwdt_close(struct inode *inode, struct file *file) |
245 | { |
246 | if (expect_close == 42) { |
247 | ibwdt_disable(); |
248 | } else { |
249 | printk(KERN_CRIT PFX |
250 | "WDT device closed unexpectedly. WDT will not stop!\n"); |
251 | ibwdt_ping(); |
252 | } |
253 | clear_bit(0, &ibwdt_is_open); |
254 | expect_close = 0; |
255 | return 0; |
256 | } |
257 | |
258 | /* |
259 | * Kernel Interfaces |
260 | */ |
261 | |
262 | static const struct file_operations ibwdt_fops = { |
263 | .owner = THIS_MODULE, |
264 | .llseek = no_llseek, |
265 | .write = ibwdt_write, |
266 | .unlocked_ioctl = ibwdt_ioctl, |
267 | .open = ibwdt_open, |
268 | .release = ibwdt_close, |
269 | }; |
270 | |
271 | static struct miscdevice ibwdt_miscdev = { |
272 | .minor = WATCHDOG_MINOR, |
273 | .name = "watchdog", |
274 | .fops = &ibwdt_fops, |
275 | }; |
276 | |
277 | /* |
278 | * Init & exit routines |
279 | */ |
280 | |
281 | static int __devinit ibwdt_probe(struct platform_device *dev) |
282 | { |
283 | int res; |
284 | |
285 | #if WDT_START != WDT_STOP |
286 | if (!request_region(WDT_STOP, 1, "IB700 WDT")) { |
287 | printk(KERN_ERR PFX "STOP method I/O %X is not available.\n", |
288 | WDT_STOP); |
289 | res = -EIO; |
290 | goto out_nostopreg; |
291 | } |
292 | #endif |
293 | |
294 | if (!request_region(WDT_START, 1, "IB700 WDT")) { |
295 | printk(KERN_ERR PFX "START method I/O %X is not available.\n", |
296 | WDT_START); |
297 | res = -EIO; |
298 | goto out_nostartreg; |
299 | } |
300 | |
301 | /* Check that the heartbeat value is within it's range ; |
302 | * if not reset to the default */ |
303 | if (ibwdt_set_heartbeat(timeout)) { |
304 | ibwdt_set_heartbeat(WATCHDOG_TIMEOUT); |
305 | printk(KERN_INFO PFX |
306 | "timeout value must be 0<=x<=30, using %d\n", timeout); |
307 | } |
308 | |
309 | res = misc_register(&ibwdt_miscdev); |
310 | if (res) { |
311 | printk(KERN_ERR PFX "failed to register misc device\n"); |
312 | goto out_nomisc; |
313 | } |
314 | return 0; |
315 | |
316 | out_nomisc: |
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 | return res; |
324 | } |
325 | |
326 | static int __devexit ibwdt_remove(struct platform_device *dev) |
327 | { |
328 | misc_deregister(&ibwdt_miscdev); |
329 | release_region(WDT_START, 1); |
330 | #if WDT_START != WDT_STOP |
331 | release_region(WDT_STOP, 1); |
332 | #endif |
333 | return 0; |
334 | } |
335 | |
336 | static void ibwdt_shutdown(struct platform_device *dev) |
337 | { |
338 | /* Turn the WDT off if we have a soft shutdown */ |
339 | ibwdt_disable(); |
340 | } |
341 | |
342 | static struct platform_driver ibwdt_driver = { |
343 | .probe = ibwdt_probe, |
344 | .remove = __devexit_p(ibwdt_remove), |
345 | .shutdown = ibwdt_shutdown, |
346 | .driver = { |
347 | .owner = THIS_MODULE, |
348 | .name = DRV_NAME, |
349 | }, |
350 | }; |
351 | |
352 | static int __init ibwdt_init(void) |
353 | { |
354 | int err; |
355 | |
356 | printk(KERN_INFO PFX |
357 | "WDT driver for IB700 single board computer initialising.\n"); |
358 | |
359 | err = platform_driver_register(&ibwdt_driver); |
360 | if (err) |
361 | return err; |
362 | |
363 | ibwdt_platform_device = platform_device_register_simple(DRV_NAME, |
364 | -1, NULL, 0); |
365 | if (IS_ERR(ibwdt_platform_device)) { |
366 | err = PTR_ERR(ibwdt_platform_device); |
367 | goto unreg_platform_driver; |
368 | } |
369 | |
370 | return 0; |
371 | |
372 | unreg_platform_driver: |
373 | platform_driver_unregister(&ibwdt_driver); |
374 | return err; |
375 | } |
376 | |
377 | static void __exit ibwdt_exit(void) |
378 | { |
379 | platform_device_unregister(ibwdt_platform_device); |
380 | platform_driver_unregister(&ibwdt_driver); |
381 | printk(KERN_INFO PFX "Watchdog Module Unloaded.\n"); |
382 | } |
383 | |
384 | module_init(ibwdt_init); |
385 | module_exit(ibwdt_exit); |
386 | |
387 | MODULE_AUTHOR("Charles Howes <chowes@vsol.net>"); |
388 | MODULE_DESCRIPTION("IB700 SBC watchdog driver"); |
389 | MODULE_LICENSE("GPL"); |
390 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
391 | |
392 | /* end of ib700wdt.c */ |
393 |
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