diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/char/watchdog/acquirewdt.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/char/watchdog/acquirewdt.c')
-rw-r--r-- | drivers/char/watchdog/acquirewdt.c | 332 |
1 files changed, 332 insertions, 0 deletions
diff --git a/drivers/char/watchdog/acquirewdt.c b/drivers/char/watchdog/acquirewdt.c new file mode 100644 index 000000000000..8f302121741b --- /dev/null +++ b/drivers/char/watchdog/acquirewdt.c | |||
@@ -0,0 +1,332 @@ | |||
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 | |||
51 | #include <linux/module.h> | ||
52 | #include <linux/moduleparam.h> | ||
53 | #include <linux/types.h> | ||
54 | #include <linux/miscdevice.h> | ||
55 | #include <linux/watchdog.h> | ||
56 | #include <linux/fs.h> | ||
57 | #include <linux/ioport.h> | ||
58 | #include <linux/notifier.h> | ||
59 | #include <linux/reboot.h> | ||
60 | #include <linux/init.h> | ||
61 | |||
62 | #include <asm/io.h> | ||
63 | #include <asm/uaccess.h> | ||
64 | #include <asm/system.h> | ||
65 | |||
66 | #define WATCHDOG_NAME "Acquire WDT" | ||
67 | #define PFX WATCHDOG_NAME ": " | ||
68 | #define WATCHDOG_HEARTBEAT 0 /* There is no way to see what the correct time-out period is */ | ||
69 | |||
70 | static unsigned long acq_is_open; | ||
71 | static char expect_close; | ||
72 | |||
73 | /* | ||
74 | * You must set these - there is no sane way to probe for this board. | ||
75 | */ | ||
76 | |||
77 | static int wdt_stop = 0x43; | ||
78 | module_param(wdt_stop, int, 0); | ||
79 | MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)"); | ||
80 | |||
81 | static int wdt_start = 0x443; | ||
82 | module_param(wdt_start, int, 0); | ||
83 | MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)"); | ||
84 | |||
85 | #ifdef CONFIG_WATCHDOG_NOWAYOUT | ||
86 | static int nowayout = 1; | ||
87 | #else | ||
88 | static int nowayout = 0; | ||
89 | #endif | ||
90 | |||
91 | module_param(nowayout, int, 0); | ||
92 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); | ||
93 | |||
94 | /* | ||
95 | * Kernel methods. | ||
96 | */ | ||
97 | |||
98 | static void acq_keepalive(void) | ||
99 | { | ||
100 | /* Write a watchdog value */ | ||
101 | inb_p(wdt_start); | ||
102 | } | ||
103 | |||
104 | static void acq_stop(void) | ||
105 | { | ||
106 | /* Turn the card off */ | ||
107 | inb_p(wdt_stop); | ||
108 | } | ||
109 | |||
110 | /* | ||
111 | * /dev/watchdog handling. | ||
112 | */ | ||
113 | |||
114 | static ssize_t acq_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | ||
115 | { | ||
116 | /* See if we got the magic character 'V' and reload the timer */ | ||
117 | if(count) { | ||
118 | if (!nowayout) { | ||
119 | size_t i; | ||
120 | |||
121 | /* note: just in case someone wrote the magic character | ||
122 | * five months ago... */ | ||
123 | expect_close = 0; | ||
124 | |||
125 | /* scan to see whether or not we got the magic character */ | ||
126 | for (i = 0; i != count; i++) { | ||
127 | char c; | ||
128 | if (get_user(c, buf + i)) | ||
129 | return -EFAULT; | ||
130 | if (c == 'V') | ||
131 | expect_close = 42; | ||
132 | } | ||
133 | } | ||
134 | |||
135 | /* Well, anyhow someone wrote to us, we should return that favour */ | ||
136 | acq_keepalive(); | ||
137 | } | ||
138 | return count; | ||
139 | } | ||
140 | |||
141 | static int acq_ioctl(struct inode *inode, struct file *file, unsigned int cmd, | ||
142 | unsigned long arg) | ||
143 | { | ||
144 | int options, retval = -EINVAL; | ||
145 | void __user *argp = (void __user *)arg; | ||
146 | int __user *p = argp; | ||
147 | static struct watchdog_info ident = | ||
148 | { | ||
149 | .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, | ||
150 | .firmware_version = 1, | ||
151 | .identity = "Acquire WDT", | ||
152 | }; | ||
153 | |||
154 | switch(cmd) | ||
155 | { | ||
156 | case WDIOC_GETSUPPORT: | ||
157 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; | ||
158 | |||
159 | case WDIOC_GETSTATUS: | ||
160 | case WDIOC_GETBOOTSTATUS: | ||
161 | return put_user(0, p); | ||
162 | |||
163 | case WDIOC_KEEPALIVE: | ||
164 | acq_keepalive(); | ||
165 | return 0; | ||
166 | |||
167 | case WDIOC_GETTIMEOUT: | ||
168 | return put_user(WATCHDOG_HEARTBEAT, p); | ||
169 | |||
170 | case WDIOC_SETOPTIONS: | ||
171 | { | ||
172 | if (get_user(options, p)) | ||
173 | return -EFAULT; | ||
174 | |||
175 | if (options & WDIOS_DISABLECARD) | ||
176 | { | ||
177 | acq_stop(); | ||
178 | retval = 0; | ||
179 | } | ||
180 | |||
181 | if (options & WDIOS_ENABLECARD) | ||
182 | { | ||
183 | acq_keepalive(); | ||
184 | retval = 0; | ||
185 | } | ||
186 | |||
187 | return retval; | ||
188 | } | ||
189 | |||
190 | default: | ||
191 | return -ENOIOCTLCMD; | ||
192 | } | ||
193 | } | ||
194 | |||
195 | static int acq_open(struct inode *inode, struct file *file) | ||
196 | { | ||
197 | if (test_and_set_bit(0, &acq_is_open)) | ||
198 | return -EBUSY; | ||
199 | |||
200 | if (nowayout) | ||
201 | __module_get(THIS_MODULE); | ||
202 | |||
203 | /* Activate */ | ||
204 | acq_keepalive(); | ||
205 | return nonseekable_open(inode, file); | ||
206 | } | ||
207 | |||
208 | static int acq_close(struct inode *inode, struct file *file) | ||
209 | { | ||
210 | if (expect_close == 42) { | ||
211 | acq_stop(); | ||
212 | } else { | ||
213 | printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); | ||
214 | acq_keepalive(); | ||
215 | } | ||
216 | clear_bit(0, &acq_is_open); | ||
217 | expect_close = 0; | ||
218 | return 0; | ||
219 | } | ||
220 | |||
221 | /* | ||
222 | * Notifier for system down | ||
223 | */ | ||
224 | |||
225 | static int acq_notify_sys(struct notifier_block *this, unsigned long code, | ||
226 | void *unused) | ||
227 | { | ||
228 | if(code==SYS_DOWN || code==SYS_HALT) { | ||
229 | /* Turn the WDT off */ | ||
230 | acq_stop(); | ||
231 | } | ||
232 | return NOTIFY_DONE; | ||
233 | } | ||
234 | |||
235 | /* | ||
236 | * Kernel Interfaces | ||
237 | */ | ||
238 | |||
239 | static struct file_operations acq_fops = { | ||
240 | .owner = THIS_MODULE, | ||
241 | .llseek = no_llseek, | ||
242 | .write = acq_write, | ||
243 | .ioctl = acq_ioctl, | ||
244 | .open = acq_open, | ||
245 | .release = acq_close, | ||
246 | }; | ||
247 | |||
248 | static struct miscdevice acq_miscdev= | ||
249 | { | ||
250 | .minor = WATCHDOG_MINOR, | ||
251 | .name = "watchdog", | ||
252 | .fops = &acq_fops, | ||
253 | }; | ||
254 | |||
255 | /* | ||
256 | * The WDT card needs to learn about soft shutdowns in order to | ||
257 | * turn the timebomb registers off. | ||
258 | */ | ||
259 | |||
260 | static struct notifier_block acq_notifier = | ||
261 | { | ||
262 | .notifier_call = acq_notify_sys, | ||
263 | }; | ||
264 | |||
265 | static int __init acq_init(void) | ||
266 | { | ||
267 | int ret; | ||
268 | |||
269 | printk(KERN_INFO "WDT driver for Acquire single board computer initialising.\n"); | ||
270 | |||
271 | if (wdt_stop != wdt_start) { | ||
272 | if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) { | ||
273 | printk (KERN_ERR PFX "I/O address 0x%04x already in use\n", | ||
274 | wdt_stop); | ||
275 | ret = -EIO; | ||
276 | goto out; | ||
277 | } | ||
278 | } | ||
279 | |||
280 | if (!request_region(wdt_start, 1, WATCHDOG_NAME)) { | ||
281 | printk (KERN_ERR PFX "I/O address 0x%04x already in use\n", | ||
282 | wdt_start); | ||
283 | ret = -EIO; | ||
284 | goto unreg_stop; | ||
285 | } | ||
286 | |||
287 | ret = register_reboot_notifier(&acq_notifier); | ||
288 | if (ret != 0) { | ||
289 | printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", | ||
290 | ret); | ||
291 | goto unreg_regions; | ||
292 | } | ||
293 | |||
294 | ret = misc_register(&acq_miscdev); | ||
295 | if (ret != 0) { | ||
296 | printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", | ||
297 | WATCHDOG_MINOR, ret); | ||
298 | goto unreg_reboot; | ||
299 | } | ||
300 | |||
301 | printk (KERN_INFO PFX "initialized. (nowayout=%d)\n", | ||
302 | nowayout); | ||
303 | |||
304 | return 0; | ||
305 | |||
306 | unreg_reboot: | ||
307 | unregister_reboot_notifier(&acq_notifier); | ||
308 | unreg_regions: | ||
309 | release_region(wdt_start, 1); | ||
310 | unreg_stop: | ||
311 | if (wdt_stop != wdt_start) | ||
312 | release_region(wdt_stop, 1); | ||
313 | out: | ||
314 | return ret; | ||
315 | } | ||
316 | |||
317 | static void __exit acq_exit(void) | ||
318 | { | ||
319 | misc_deregister(&acq_miscdev); | ||
320 | unregister_reboot_notifier(&acq_notifier); | ||
321 | if(wdt_stop != wdt_start) | ||
322 | release_region(wdt_stop,1); | ||
323 | release_region(wdt_start,1); | ||
324 | } | ||
325 | |||
326 | module_init(acq_init); | ||
327 | module_exit(acq_exit); | ||
328 | |||
329 | MODULE_AUTHOR("David Woodhouse"); | ||
330 | MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver"); | ||
331 | MODULE_LICENSE("GPL"); | ||
332 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | ||