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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 | * | |
29fa0586 AC |
6 | * (c) Copyright 1996 Alan Cox <[email protected]>, |
7 | * All Rights Reserved. | |
1da177e4 LT |
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 | * | |
29fa0586 | 18 | * (c) Copyright 1995 Alan Cox <[email protected]> |
1da177e4 LT |
19 | * |
20 | * 14-Dec-2001 Matt Domsch <[email protected]> | |
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/... */ | |
94da1e2e AC |
61 | #include <linux/miscdevice.h> /* For MODULE_ALIAS_MISCDEV |
62 | (WATCHDOG_MINOR) */ | |
76c11f04 WVS |
63 | #include <linux/watchdog.h> /* For the watchdog specific items */ |
64 | #include <linux/fs.h> /* For file operations */ | |
65 | #include <linux/ioport.h> /* For io-port access */ | |
ad5fe323 | 66 | #include <linux/platform_device.h> /* For platform_driver framework */ |
76c11f04 | 67 | #include <linux/init.h> /* For __init/__exit/... */ |
94da1e2e AC |
68 | #include <linux/uaccess.h> /* For copy_to_user/put_user/... */ |
69 | #include <linux/io.h> /* For inb/outb/... */ | |
76c11f04 WVS |
70 | |
71 | /* Module information */ | |
72 | #define DRV_NAME "acquirewdt" | |
73 | #define PFX DRV_NAME ": " | |
1da177e4 | 74 | #define WATCHDOG_NAME "Acquire WDT" |
94da1e2e AC |
75 | /* There is no way to see what the correct time-out period is */ |
76 | #define WATCHDOG_HEARTBEAT 0 | |
1da177e4 | 77 | |
76c11f04 | 78 | /* internal variables */ |
94da1e2e AC |
79 | /* the watchdog platform device */ |
80 | static struct platform_device *acq_platform_device; | |
1da177e4 LT |
81 | static unsigned long acq_is_open; |
82 | static char expect_close; | |
83 | ||
76c11f04 | 84 | /* module parameters */ |
94da1e2e AC |
85 | /* You must set this - there is no sane way to probe for this board. */ |
86 | static int wdt_stop = 0x43; | |
1da177e4 LT |
87 | module_param(wdt_stop, int, 0); |
88 | MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)"); | |
89 | ||
94da1e2e AC |
90 | /* You must set this - there is no sane way to probe for this board. */ |
91 | static int wdt_start = 0x443; | |
1da177e4 LT |
92 | module_param(wdt_start, int, 0); |
93 | MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)"); | |
94 | ||
4bfdf378 | 95 | static int nowayout = WATCHDOG_NOWAYOUT; |
1da177e4 | 96 | module_param(nowayout, int, 0); |
94da1e2e AC |
97 | MODULE_PARM_DESC(nowayout, |
98 | "Watchdog cannot be stopped once started (default=" | |
99 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
1da177e4 LT |
100 | |
101 | /* | |
76c11f04 | 102 | * Watchdog Operations |
1da177e4 LT |
103 | */ |
104 | ||
105 | static void acq_keepalive(void) | |
106 | { | |
107 | /* Write a watchdog value */ | |
108 | inb_p(wdt_start); | |
109 | } | |
110 | ||
111 | static void acq_stop(void) | |
112 | { | |
113 | /* Turn the card off */ | |
114 | inb_p(wdt_stop); | |
115 | } | |
116 | ||
117 | /* | |
76c11f04 | 118 | * /dev/watchdog handling |
1da177e4 LT |
119 | */ |
120 | ||
94da1e2e AC |
121 | static ssize_t acq_write(struct file *file, const char __user *buf, |
122 | size_t count, loff_t *ppos) | |
1da177e4 LT |
123 | { |
124 | /* See if we got the magic character 'V' and reload the timer */ | |
94da1e2e | 125 | if (count) { |
1da177e4 LT |
126 | if (!nowayout) { |
127 | size_t i; | |
1da177e4 | 128 | /* note: just in case someone wrote the magic character |
7944d3a5 | 129 | five months ago... */ |
1da177e4 | 130 | expect_close = 0; |
94da1e2e AC |
131 | /* scan to see whether or not we got the |
132 | magic character */ | |
1da177e4 LT |
133 | for (i = 0; i != count; i++) { |
134 | char c; | |
135 | if (get_user(c, buf + i)) | |
136 | return -EFAULT; | |
137 | if (c == 'V') | |
138 | expect_close = 42; | |
139 | } | |
140 | } | |
94da1e2e AC |
141 | /* Well, anyhow someone wrote to us, we should |
142 | return that favour */ | |
1da177e4 LT |
143 | acq_keepalive(); |
144 | } | |
145 | return count; | |
146 | } | |
147 | ||
94da1e2e | 148 | static long acq_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
1da177e4 LT |
149 | { |
150 | int options, retval = -EINVAL; | |
151 | void __user *argp = (void __user *)arg; | |
152 | int __user *p = argp; | |
94da1e2e | 153 | static struct watchdog_info ident = { |
1da177e4 LT |
154 | .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
155 | .firmware_version = 1, | |
76c11f04 | 156 | .identity = WATCHDOG_NAME, |
1da177e4 LT |
157 | }; |
158 | ||
94da1e2e | 159 | switch (cmd) { |
1da177e4 | 160 | case WDIOC_GETSUPPORT: |
94da1e2e | 161 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; |
1da177e4 LT |
162 | |
163 | case WDIOC_GETSTATUS: | |
164 | case WDIOC_GETBOOTSTATUS: | |
94da1e2e | 165 | return put_user(0, p); |
1da177e4 | 166 | |
1da177e4 LT |
167 | case WDIOC_SETOPTIONS: |
168 | { | |
94da1e2e AC |
169 | if (get_user(options, p)) |
170 | return -EFAULT; | |
171 | if (options & WDIOS_DISABLECARD) { | |
172 | acq_stop(); | |
173 | retval = 0; | |
174 | } | |
175 | if (options & WDIOS_ENABLECARD) { | |
176 | acq_keepalive(); | |
177 | retval = 0; | |
178 | } | |
179 | return retval; | |
1da177e4 | 180 | } |
0c06090c WVS |
181 | case WDIOC_KEEPALIVE: |
182 | acq_keepalive(); | |
183 | return 0; | |
184 | ||
185 | case WDIOC_GETTIMEOUT: | |
186 | return put_user(WATCHDOG_HEARTBEAT, p); | |
187 | ||
1da177e4 | 188 | default: |
94da1e2e | 189 | return -ENOTTY; |
1da177e4 LT |
190 | } |
191 | } | |
192 | ||
193 | static int acq_open(struct inode *inode, struct file *file) | |
194 | { | |
195 | if (test_and_set_bit(0, &acq_is_open)) | |
196 | return -EBUSY; | |
197 | ||
198 | if (nowayout) | |
199 | __module_get(THIS_MODULE); | |
200 | ||
201 | /* Activate */ | |
202 | acq_keepalive(); | |
203 | return nonseekable_open(inode, file); | |
204 | } | |
205 | ||
206 | static int acq_close(struct inode *inode, struct file *file) | |
207 | { | |
208 | if (expect_close == 42) { | |
209 | acq_stop(); | |
210 | } else { | |
94da1e2e AC |
211 | printk(KERN_CRIT PFX |
212 | "Unexpected close, not stopping watchdog!\n"); | |
1da177e4 LT |
213 | acq_keepalive(); |
214 | } | |
215 | clear_bit(0, &acq_is_open); | |
216 | expect_close = 0; | |
217 | return 0; | |
218 | } | |
219 | ||
1da177e4 LT |
220 | /* |
221 | * Kernel Interfaces | |
222 | */ | |
223 | ||
62322d25 | 224 | static const struct file_operations acq_fops = { |
1da177e4 LT |
225 | .owner = THIS_MODULE, |
226 | .llseek = no_llseek, | |
227 | .write = acq_write, | |
94da1e2e | 228 | .unlocked_ioctl = acq_ioctl, |
1da177e4 LT |
229 | .open = acq_open, |
230 | .release = acq_close, | |
231 | }; | |
232 | ||
76c11f04 WVS |
233 | static struct miscdevice acq_miscdev = { |
234 | .minor = WATCHDOG_MINOR, | |
235 | .name = "watchdog", | |
236 | .fops = &acq_fops, | |
1da177e4 LT |
237 | }; |
238 | ||
76c11f04 WVS |
239 | /* |
240 | * Init & exit routines | |
241 | */ | |
242 | ||
ad5fe323 | 243 | static int __devinit acq_probe(struct platform_device *dev) |
1da177e4 LT |
244 | { |
245 | int ret; | |
246 | ||
1da177e4 LT |
247 | if (wdt_stop != wdt_start) { |
248 | if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) { | |
94da1e2e AC |
249 | printk(KERN_ERR PFX |
250 | "I/O address 0x%04x already in use\n", wdt_stop); | |
1da177e4 LT |
251 | ret = -EIO; |
252 | goto out; | |
253 | } | |
254 | } | |
255 | ||
256 | if (!request_region(wdt_start, 1, WATCHDOG_NAME)) { | |
94da1e2e | 257 | printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", |
1da177e4 LT |
258 | wdt_start); |
259 | ret = -EIO; | |
260 | goto unreg_stop; | |
261 | } | |
1da177e4 LT |
262 | ret = misc_register(&acq_miscdev); |
263 | if (ret != 0) { | |
94da1e2e AC |
264 | printk(KERN_ERR PFX |
265 | "cannot register miscdev on minor=%d (err=%d)\n", | |
266 | WATCHDOG_MINOR, ret); | |
98c08e98 | 267 | goto unreg_regions; |
1da177e4 | 268 | } |
94da1e2e | 269 | printk(KERN_INFO PFX "initialized. (nowayout=%d)\n", nowayout); |
1da177e4 LT |
270 | |
271 | return 0; | |
1da177e4 LT |
272 | unreg_regions: |
273 | release_region(wdt_start, 1); | |
274 | unreg_stop: | |
275 | if (wdt_stop != wdt_start) | |
276 | release_region(wdt_stop, 1); | |
277 | out: | |
278 | return ret; | |
279 | } | |
280 | ||
ad5fe323 | 281 | static int __devexit acq_remove(struct platform_device *dev) |
1da177e4 LT |
282 | { |
283 | misc_deregister(&acq_miscdev); | |
94da1e2e AC |
284 | release_region(wdt_start, 1); |
285 | if (wdt_stop != wdt_start) | |
286 | release_region(wdt_stop, 1); | |
ad5fe323 WVS |
287 | |
288 | return 0; | |
289 | } | |
290 | ||
98c08e98 WVS |
291 | static void acq_shutdown(struct platform_device *dev) |
292 | { | |
293 | /* Turn the WDT off if we have a soft shutdown */ | |
294 | acq_stop(); | |
295 | } | |
296 | ||
ad5fe323 WVS |
297 | static struct platform_driver acquirewdt_driver = { |
298 | .probe = acq_probe, | |
299 | .remove = __devexit_p(acq_remove), | |
98c08e98 | 300 | .shutdown = acq_shutdown, |
ad5fe323 WVS |
301 | .driver = { |
302 | .owner = THIS_MODULE, | |
303 | .name = DRV_NAME, | |
304 | }, | |
305 | }; | |
306 | ||
307 | static int __init acq_init(void) | |
308 | { | |
309 | int err; | |
310 | ||
94da1e2e AC |
311 | printk(KERN_INFO |
312 | "WDT driver for Acquire single board computer initialising.\n"); | |
ad5fe323 WVS |
313 | |
314 | err = platform_driver_register(&acquirewdt_driver); | |
315 | if (err) | |
316 | return err; | |
317 | ||
94da1e2e AC |
318 | acq_platform_device = platform_device_register_simple(DRV_NAME, |
319 | -1, NULL, 0); | |
ad5fe323 WVS |
320 | if (IS_ERR(acq_platform_device)) { |
321 | err = PTR_ERR(acq_platform_device); | |
322 | goto unreg_platform_driver; | |
323 | } | |
ad5fe323 WVS |
324 | return 0; |
325 | ||
326 | unreg_platform_driver: | |
327 | platform_driver_unregister(&acquirewdt_driver); | |
328 | return err; | |
329 | } | |
330 | ||
331 | static void __exit acq_exit(void) | |
332 | { | |
333 | platform_device_unregister(acq_platform_device); | |
334 | platform_driver_unregister(&acquirewdt_driver); | |
335 | printk(KERN_INFO PFX "Watchdog Module Unloaded.\n"); | |
1da177e4 LT |
336 | } |
337 | ||
338 | module_init(acq_init); | |
339 | module_exit(acq_exit); | |
340 | ||
341 | MODULE_AUTHOR("David Woodhouse"); | |
342 | MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver"); | |
343 | MODULE_LICENSE("GPL"); | |
344 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |