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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Acquire Single Board Computer Watchdog Timer driver | |
3 | * | |
4 | * Based on wdt.c. Original copyright messages: | |
5 | * | |
6 | * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved. | |
7 | * http://www.redhat.com | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU General Public License | |
11 | * as published by the Free Software Foundation; either version | |
12 | * 2 of the License, or (at your option) any later version. | |
13 | * | |
14 | * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide | |
15 | * warranty for any of this software. This material is provided | |
16 | * "AS-IS" and at no charge. | |
17 | * | |
18 | * (c) Copyright 1995 Alan Cox <alan@redhat.com> | |
19 | * | |
20 | * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> | |
21 | * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT | |
22 | * Can't add timeout - driver doesn't allow changing value | |
23 | */ | |
24 | ||
25 | /* | |
26 | * Theory of Operation: | |
27 | * The Watch-Dog Timer is provided to ensure that standalone | |
28 | * Systems can always recover from catastrophic conditions that | |
29 | * caused the CPU to crash. This condition may have occured by | |
30 | * external EMI or a software bug. When the CPU stops working | |
31 | * correctly, hardware on the board will either perform a hardware | |
32 | * reset (cold boot) or a non-maskable interrupt (NMI) to bring the | |
33 | * system back to a known state. | |
34 | * | |
35 | * The Watch-Dog Timer is controlled by two I/O Ports. | |
36 | * 443 hex - Read - Enable or refresh the Watch-Dog Timer | |
37 | * 043 hex - Read - Disable the Watch-Dog Timer | |
38 | * | |
39 | * To enable the Watch-Dog Timer, a read from I/O port 443h must | |
40 | * be performed. This will enable and activate the countdown timer | |
41 | * which will eventually time out and either reset the CPU or cause | |
42 | * an NMI depending on the setting of a jumper. To ensure that this | |
43 | * reset condition does not occur, the Watch-Dog Timer must be | |
44 | * periodically refreshed by reading the same I/O port 443h. | |
45 | * The Watch-Dog Timer is disabled by reading I/O port 043h. | |
46 | * | |
47 | * The Watch-Dog Timer Time-Out Period is set via jumpers. | |
48 | * It can be 1, 2, 10, 20, 110 or 220 seconds. | |
49 | */ | |
50 | ||
76c11f04 WVS |
51 | /* |
52 | * Includes, defines, variables, module parameters, ... | |
53 | */ | |
1da177e4 | 54 | |
76c11f04 WVS |
55 | /* Includes */ |
56 | #include <linux/module.h> /* For module specific items */ | |
57 | #include <linux/moduleparam.h> /* For new moduleparam's */ | |
58 | #include <linux/types.h> /* For standard types (like size_t) */ | |
59 | #include <linux/errno.h> /* For the -ENODEV/... values */ | |
60 | #include <linux/kernel.h> /* For printk/panic/... */ | |
61 | #include <linux/miscdevice.h> /* For MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR) */ | |
62 | #include <linux/watchdog.h> /* For the watchdog specific items */ | |
63 | #include <linux/fs.h> /* For file operations */ | |
64 | #include <linux/ioport.h> /* For io-port access */ | |
65 | #include <linux/notifier.h> /* For reboot notifier */ | |
66 | #include <linux/reboot.h> /* For reboot notifier */ | |
ad5fe323 | 67 | #include <linux/platform_device.h> /* For platform_driver framework */ |
76c11f04 WVS |
68 | #include <linux/init.h> /* For __init/__exit/... */ |
69 | ||
70 | #include <asm/uaccess.h> /* For copy_to_user/put_user/... */ | |
71 | #include <asm/io.h> /* For inb/outb/... */ | |
72 | ||
73 | /* Module information */ | |
74 | #define DRV_NAME "acquirewdt" | |
75 | #define PFX DRV_NAME ": " | |
1da177e4 | 76 | #define WATCHDOG_NAME "Acquire WDT" |
1da177e4 LT |
77 | #define WATCHDOG_HEARTBEAT 0 /* There is no way to see what the correct time-out period is */ |
78 | ||
76c11f04 | 79 | /* internal variables */ |
ad5fe323 | 80 | static struct platform_device *acq_platform_device; /* the watchdog platform device */ |
1da177e4 LT |
81 | static unsigned long acq_is_open; |
82 | static char expect_close; | |
83 | ||
76c11f04 WVS |
84 | /* module parameters */ |
85 | static int wdt_stop = 0x43; /* You must set this - there is no sane way to probe for this board. */ | |
1da177e4 LT |
86 | module_param(wdt_stop, int, 0); |
87 | MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)"); | |
88 | ||
76c11f04 | 89 | static int wdt_start = 0x443; /* You must set this - there is no sane way to probe for this board. */ |
1da177e4 LT |
90 | module_param(wdt_start, int, 0); |
91 | MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)"); | |
92 | ||
4bfdf378 | 93 | static int nowayout = WATCHDOG_NOWAYOUT; |
1da177e4 | 94 | module_param(nowayout, int, 0); |
76c11f04 | 95 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
1da177e4 LT |
96 | |
97 | /* | |
76c11f04 | 98 | * Watchdog Operations |
1da177e4 LT |
99 | */ |
100 | ||
101 | static void acq_keepalive(void) | |
102 | { | |
103 | /* Write a watchdog value */ | |
104 | inb_p(wdt_start); | |
105 | } | |
106 | ||
107 | static void acq_stop(void) | |
108 | { | |
109 | /* Turn the card off */ | |
110 | inb_p(wdt_stop); | |
111 | } | |
112 | ||
113 | /* | |
76c11f04 | 114 | * /dev/watchdog handling |
1da177e4 LT |
115 | */ |
116 | ||
117 | static ssize_t acq_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
118 | { | |
119 | /* See if we got the magic character 'V' and reload the timer */ | |
120 | if(count) { | |
121 | if (!nowayout) { | |
122 | size_t i; | |
123 | ||
124 | /* note: just in case someone wrote the magic character | |
125 | * five months ago... */ | |
126 | expect_close = 0; | |
127 | ||
128 | /* scan to see whether or not we got the magic character */ | |
129 | for (i = 0; i != count; i++) { | |
130 | char c; | |
131 | if (get_user(c, buf + i)) | |
132 | return -EFAULT; | |
133 | if (c == 'V') | |
134 | expect_close = 42; | |
135 | } | |
136 | } | |
137 | ||
138 | /* Well, anyhow someone wrote to us, we should return that favour */ | |
139 | acq_keepalive(); | |
140 | } | |
141 | return count; | |
142 | } | |
143 | ||
144 | static int acq_ioctl(struct inode *inode, struct file *file, unsigned int cmd, | |
145 | unsigned long arg) | |
146 | { | |
147 | int options, retval = -EINVAL; | |
148 | void __user *argp = (void __user *)arg; | |
149 | int __user *p = argp; | |
150 | static struct watchdog_info ident = | |
151 | { | |
152 | .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, | |
153 | .firmware_version = 1, | |
76c11f04 | 154 | .identity = WATCHDOG_NAME, |
1da177e4 LT |
155 | }; |
156 | ||
157 | switch(cmd) | |
158 | { | |
159 | case WDIOC_GETSUPPORT: | |
160 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; | |
161 | ||
162 | case WDIOC_GETSTATUS: | |
163 | case WDIOC_GETBOOTSTATUS: | |
164 | return put_user(0, p); | |
165 | ||
166 | case WDIOC_KEEPALIVE: | |
167 | acq_keepalive(); | |
168 | return 0; | |
169 | ||
170 | case WDIOC_GETTIMEOUT: | |
171 | return put_user(WATCHDOG_HEARTBEAT, p); | |
172 | ||
173 | case WDIOC_SETOPTIONS: | |
174 | { | |
175 | if (get_user(options, p)) | |
176 | return -EFAULT; | |
177 | ||
178 | if (options & WDIOS_DISABLECARD) | |
179 | { | |
180 | acq_stop(); | |
181 | retval = 0; | |
182 | } | |
183 | ||
184 | if (options & WDIOS_ENABLECARD) | |
185 | { | |
186 | acq_keepalive(); | |
187 | retval = 0; | |
188 | } | |
189 | ||
190 | return retval; | |
191 | } | |
192 | ||
193 | default: | |
795b89d2 | 194 | return -ENOTTY; |
1da177e4 LT |
195 | } |
196 | } | |
197 | ||
198 | static int acq_open(struct inode *inode, struct file *file) | |
199 | { | |
200 | if (test_and_set_bit(0, &acq_is_open)) | |
201 | return -EBUSY; | |
202 | ||
203 | if (nowayout) | |
204 | __module_get(THIS_MODULE); | |
205 | ||
206 | /* Activate */ | |
207 | acq_keepalive(); | |
208 | return nonseekable_open(inode, file); | |
209 | } | |
210 | ||
211 | static int acq_close(struct inode *inode, struct file *file) | |
212 | { | |
213 | if (expect_close == 42) { | |
214 | acq_stop(); | |
215 | } else { | |
216 | printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); | |
217 | acq_keepalive(); | |
218 | } | |
219 | clear_bit(0, &acq_is_open); | |
220 | expect_close = 0; | |
221 | return 0; | |
222 | } | |
223 | ||
224 | /* | |
225 | * Notifier for system down | |
226 | */ | |
227 | ||
228 | static int acq_notify_sys(struct notifier_block *this, unsigned long code, | |
229 | void *unused) | |
230 | { | |
231 | if(code==SYS_DOWN || code==SYS_HALT) { | |
232 | /* Turn the WDT off */ | |
233 | acq_stop(); | |
234 | } | |
235 | return NOTIFY_DONE; | |
236 | } | |
237 | ||
238 | /* | |
239 | * Kernel Interfaces | |
240 | */ | |
241 | ||
62322d25 | 242 | static const struct file_operations acq_fops = { |
1da177e4 LT |
243 | .owner = THIS_MODULE, |
244 | .llseek = no_llseek, | |
245 | .write = acq_write, | |
246 | .ioctl = acq_ioctl, | |
247 | .open = acq_open, | |
248 | .release = acq_close, | |
249 | }; | |
250 | ||
76c11f04 WVS |
251 | static struct miscdevice acq_miscdev = { |
252 | .minor = WATCHDOG_MINOR, | |
253 | .name = "watchdog", | |
254 | .fops = &acq_fops, | |
1da177e4 LT |
255 | }; |
256 | ||
257 | /* | |
258 | * The WDT card needs to learn about soft shutdowns in order to | |
259 | * turn the timebomb registers off. | |
260 | */ | |
261 | ||
76c11f04 | 262 | static struct notifier_block acq_notifier = { |
1da177e4 LT |
263 | .notifier_call = acq_notify_sys, |
264 | }; | |
265 | ||
76c11f04 WVS |
266 | /* |
267 | * Init & exit routines | |
268 | */ | |
269 | ||
ad5fe323 | 270 | static int __devinit acq_probe(struct platform_device *dev) |
1da177e4 LT |
271 | { |
272 | int ret; | |
273 | ||
1da177e4 LT |
274 | if (wdt_stop != wdt_start) { |
275 | if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) { | |
276 | printk (KERN_ERR PFX "I/O address 0x%04x already in use\n", | |
277 | wdt_stop); | |
278 | ret = -EIO; | |
279 | goto out; | |
280 | } | |
281 | } | |
282 | ||
283 | if (!request_region(wdt_start, 1, WATCHDOG_NAME)) { | |
284 | printk (KERN_ERR PFX "I/O address 0x%04x already in use\n", | |
285 | wdt_start); | |
286 | ret = -EIO; | |
287 | goto unreg_stop; | |
288 | } | |
289 | ||
290 | ret = register_reboot_notifier(&acq_notifier); | |
291 | if (ret != 0) { | |
292 | printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", | |
293 | ret); | |
294 | goto unreg_regions; | |
295 | } | |
296 | ||
297 | ret = misc_register(&acq_miscdev); | |
298 | if (ret != 0) { | |
299 | printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", | |
300 | WATCHDOG_MINOR, ret); | |
301 | goto unreg_reboot; | |
302 | } | |
303 | ||
304 | printk (KERN_INFO PFX "initialized. (nowayout=%d)\n", | |
305 | nowayout); | |
306 | ||
307 | return 0; | |
308 | ||
309 | unreg_reboot: | |
310 | unregister_reboot_notifier(&acq_notifier); | |
311 | unreg_regions: | |
312 | release_region(wdt_start, 1); | |
313 | unreg_stop: | |
314 | if (wdt_stop != wdt_start) | |
315 | release_region(wdt_stop, 1); | |
316 | out: | |
317 | return ret; | |
318 | } | |
319 | ||
ad5fe323 | 320 | static int __devexit acq_remove(struct platform_device *dev) |
1da177e4 LT |
321 | { |
322 | misc_deregister(&acq_miscdev); | |
323 | unregister_reboot_notifier(&acq_notifier); | |
76c11f04 | 324 | release_region(wdt_start,1); |
1da177e4 LT |
325 | if(wdt_stop != wdt_start) |
326 | release_region(wdt_stop,1); | |
ad5fe323 WVS |
327 | |
328 | return 0; | |
329 | } | |
330 | ||
331 | static struct platform_driver acquirewdt_driver = { | |
332 | .probe = acq_probe, | |
333 | .remove = __devexit_p(acq_remove), | |
334 | .driver = { | |
335 | .owner = THIS_MODULE, | |
336 | .name = DRV_NAME, | |
337 | }, | |
338 | }; | |
339 | ||
340 | static int __init acq_init(void) | |
341 | { | |
342 | int err; | |
343 | ||
344 | printk(KERN_INFO "WDT driver for Acquire single board computer initialising.\n"); | |
345 | ||
346 | err = platform_driver_register(&acquirewdt_driver); | |
347 | if (err) | |
348 | return err; | |
349 | ||
350 | acq_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0); | |
351 | if (IS_ERR(acq_platform_device)) { | |
352 | err = PTR_ERR(acq_platform_device); | |
353 | goto unreg_platform_driver; | |
354 | } | |
355 | ||
356 | return 0; | |
357 | ||
358 | unreg_platform_driver: | |
359 | platform_driver_unregister(&acquirewdt_driver); | |
360 | return err; | |
361 | } | |
362 | ||
363 | static void __exit acq_exit(void) | |
364 | { | |
365 | platform_device_unregister(acq_platform_device); | |
366 | platform_driver_unregister(&acquirewdt_driver); | |
367 | printk(KERN_INFO PFX "Watchdog Module Unloaded.\n"); | |
1da177e4 LT |
368 | } |
369 | ||
370 | module_init(acq_init); | |
371 | module_exit(acq_exit); | |
372 | ||
373 | MODULE_AUTHOR("David Woodhouse"); | |
374 | MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver"); | |
375 | MODULE_LICENSE("GPL"); | |
376 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |