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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/char/watchdog/w83877f_wdt.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/w83877f_wdt.c')
-rw-r--r--drivers/char/watchdog/w83877f_wdt.c426
1 files changed, 426 insertions, 0 deletions
diff --git a/drivers/char/watchdog/w83877f_wdt.c b/drivers/char/watchdog/w83877f_wdt.c
new file mode 100644
index 000000000000..bccbd4d6ac2d
--- /dev/null
+++ b/drivers/char/watchdog/w83877f_wdt.c
@@ -0,0 +1,426 @@
1/*
2 * W83877F Computer Watchdog Timer driver
3 *
4 * Based on acquirewdt.c by Alan Cox,
5 * and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * The authors do NOT admit liability nor provide warranty for
13 * any of this software. This material is provided "AS-IS" in
14 * the hope that it may be useful for others.
15 *
16 * (c) Copyright 2001 Scott Jennings <linuxdrivers@oro.net>
17 *
18 * 4/19 - 2001 [Initial revision]
19 * 9/27 - 2001 Added spinlocking
20 * 4/12 - 2002 [rob@osinvestor.com] Eliminate extra comments
21 * Eliminate fop_read
22 * Eliminate extra spin_unlock
23 * Added KERN_* tags to printks
24 * add CONFIG_WATCHDOG_NOWAYOUT support
25 * fix possible wdt_is_open race
26 * changed watchdog_info to correctly reflect what the driver offers
27 * added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS, WDIOC_SETTIMEOUT,
28 * WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls
29 * 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces
30 * added extra printk's for startup problems
31 * use module_param
32 * made timeout (the emulated heartbeat) a module_param
33 * made the keepalive ping an internal subroutine
34 *
35 * This WDT driver is different from most other Linux WDT
36 * drivers in that the driver will ping the watchdog by itself,
37 * because this particular WDT has a very short timeout (1.6
38 * seconds) and it would be insane to count on any userspace
39 * daemon always getting scheduled within that time frame.
40 */
41
42#include <linux/module.h>
43#include <linux/moduleparam.h>
44#include <linux/types.h>
45#include <linux/timer.h>
46#include <linux/jiffies.h>
47#include <linux/miscdevice.h>
48#include <linux/watchdog.h>
49#include <linux/fs.h>
50#include <linux/ioport.h>
51#include <linux/notifier.h>
52#include <linux/reboot.h>
53#include <linux/init.h>
54#include <asm/io.h>
55#include <asm/uaccess.h>
56#include <asm/system.h>
57
58#define OUR_NAME "w83877f_wdt"
59#define PFX OUR_NAME ": "
60
61#define ENABLE_W83877F_PORT 0x3F0
62#define ENABLE_W83877F 0x87
63#define DISABLE_W83877F 0xAA
64#define WDT_PING 0x443
65#define WDT_REGISTER 0x14
66#define WDT_ENABLE 0x9C
67#define WDT_DISABLE 0x8C
68
69/*
70 * The W83877F seems to be fixed at 1.6s timeout (at least on the
71 * EMACS PC-104 board I'm using). If we reset the watchdog every
72 * ~250ms we should be safe. */
73
74#define WDT_INTERVAL (HZ/4+1)
75
76/*
77 * We must not require too good response from the userspace daemon.
78 * Here we require the userspace daemon to send us a heartbeat
79 * char to /dev/watchdog every 30 seconds.
80 */
81
82#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
83static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
84module_param(timeout, int, 0);
85MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
86
87
88#ifdef CONFIG_WATCHDOG_NOWAYOUT
89static int nowayout = 1;
90#else
91static int nowayout = 0;
92#endif
93
94module_param(nowayout, int, 0);
95MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
96
97static void wdt_timer_ping(unsigned long);
98static struct timer_list timer;
99static unsigned long next_heartbeat;
100static unsigned long wdt_is_open;
101static char wdt_expect_close;
102static spinlock_t wdt_spinlock;
103
104/*
105 * Whack the dog
106 */
107
108static void wdt_timer_ping(unsigned long data)
109{
110 /* If we got a heartbeat pulse within the WDT_US_INTERVAL
111 * we agree to ping the WDT
112 */
113 if(time_before(jiffies, next_heartbeat))
114 {
115 /* Ping the WDT */
116 spin_lock(&wdt_spinlock);
117
118 /* Ping the WDT by reading from WDT_PING */
119 inb_p(WDT_PING);
120
121 /* Re-set the timer interval */
122 timer.expires = jiffies + WDT_INTERVAL;
123 add_timer(&timer);
124
125 spin_unlock(&wdt_spinlock);
126
127 } else {
128 printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
129 }
130}
131
132/*
133 * Utility routines
134 */
135
136static void wdt_change(int writeval)
137{
138 unsigned long flags;
139 spin_lock_irqsave(&wdt_spinlock, flags);
140
141 /* buy some time */
142 inb_p(WDT_PING);
143
144 /* make W83877F available */
145 outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT);
146 outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT);
147
148 /* enable watchdog */
149 outb_p(WDT_REGISTER, ENABLE_W83877F_PORT);
150 outb_p(writeval, ENABLE_W83877F_PORT+1);
151
152 /* lock the W8387FF away */
153 outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT);
154
155 spin_unlock_irqrestore(&wdt_spinlock, flags);
156}
157
158static void wdt_startup(void)
159{
160 next_heartbeat = jiffies + (timeout * HZ);
161
162 /* Start the timer */
163 timer.expires = jiffies + WDT_INTERVAL;
164 add_timer(&timer);
165
166 wdt_change(WDT_ENABLE);
167
168 printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
169}
170
171static void wdt_turnoff(void)
172{
173 /* Stop the timer */
174 del_timer(&timer);
175
176 wdt_change(WDT_DISABLE);
177
178 printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
179}
180
181static void wdt_keepalive(void)
182{
183 /* user land ping */
184 next_heartbeat = jiffies + (timeout * HZ);
185}
186
187/*
188 * /dev/watchdog handling
189 */
190
191static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos)
192{
193 /* See if we got the magic character 'V' and reload the timer */
194 if(count)
195 {
196 if (!nowayout)
197 {
198 size_t ofs;
199
200 /* note: just in case someone wrote the magic character
201 * five months ago... */
202 wdt_expect_close = 0;
203
204 /* scan to see whether or not we got the magic character */
205 for(ofs = 0; ofs != count; ofs++)
206 {
207 char c;
208 if (get_user(c, buf + ofs))
209 return -EFAULT;
210 if (c == 'V')
211 wdt_expect_close = 42;
212 }
213 }
214
215 /* someone wrote to us, we should restart timer */
216 wdt_keepalive();
217 }
218 return count;
219}
220
221static int fop_open(struct inode * inode, struct file * file)
222{
223 /* Just in case we're already talking to someone... */
224 if(test_and_set_bit(0, &wdt_is_open))
225 return -EBUSY;
226
227 /* Good, fire up the show */
228 wdt_startup();
229 return nonseekable_open(inode, file);
230}
231
232static int fop_close(struct inode * inode, struct file * file)
233{
234 if(wdt_expect_close == 42)
235 wdt_turnoff();
236 else {
237 del_timer(&timer);
238 printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
239 }
240 clear_bit(0, &wdt_is_open);
241 wdt_expect_close = 0;
242 return 0;
243}
244
245static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
246 unsigned long arg)
247{
248 void __user *argp = (void __user *)arg;
249 int __user *p = argp;
250 static struct watchdog_info ident=
251 {
252 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
253 .firmware_version = 1,
254 .identity = "W83877F",
255 };
256
257 switch(cmd)
258 {
259 default:
260 return -ENOIOCTLCMD;
261 case WDIOC_GETSUPPORT:
262 return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
263 case WDIOC_GETSTATUS:
264 case WDIOC_GETBOOTSTATUS:
265 return put_user(0, p);
266 case WDIOC_KEEPALIVE:
267 wdt_keepalive();
268 return 0;
269 case WDIOC_SETOPTIONS:
270 {
271 int new_options, retval = -EINVAL;
272
273 if(get_user(new_options, p))
274 return -EFAULT;
275
276 if(new_options & WDIOS_DISABLECARD) {
277 wdt_turnoff();
278 retval = 0;
279 }
280
281 if(new_options & WDIOS_ENABLECARD) {
282 wdt_startup();
283 retval = 0;
284 }
285
286 return retval;
287 }
288 case WDIOC_SETTIMEOUT:
289 {
290 int new_timeout;
291
292 if(get_user(new_timeout, p))
293 return -EFAULT;
294
295 if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */
296 return -EINVAL;
297
298 timeout = new_timeout;
299 wdt_keepalive();
300 /* Fall through */
301 }
302 case WDIOC_GETTIMEOUT:
303 return put_user(timeout, p);
304 }
305}
306
307static struct file_operations wdt_fops = {
308 .owner = THIS_MODULE,
309 .llseek = no_llseek,
310 .write = fop_write,
311 .open = fop_open,
312 .release = fop_close,
313 .ioctl = fop_ioctl,
314};
315
316static struct miscdevice wdt_miscdev = {
317 .minor = WATCHDOG_MINOR,
318 .name = "watchdog",
319 .fops = &wdt_fops,
320};
321
322/*
323 * Notifier for system down
324 */
325
326static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
327 void *unused)
328{
329 if(code==SYS_DOWN || code==SYS_HALT)
330 wdt_turnoff();
331 return NOTIFY_DONE;
332}
333
334/*
335 * The WDT needs to learn about soft shutdowns in order to
336 * turn the timebomb registers off.
337 */
338
339static struct notifier_block wdt_notifier=
340{
341 .notifier_call = wdt_notify_sys,
342};
343
344static void __exit w83877f_wdt_unload(void)
345{
346 wdt_turnoff();
347
348 /* Deregister */
349 misc_deregister(&wdt_miscdev);
350
351 unregister_reboot_notifier(&wdt_notifier);
352 release_region(WDT_PING,1);
353 release_region(ENABLE_W83877F_PORT,2);
354}
355
356static int __init w83877f_wdt_init(void)
357{
358 int rc = -EBUSY;
359
360 spin_lock_init(&wdt_spinlock);
361
362 if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */
363 {
364 timeout = WATCHDOG_TIMEOUT;
365 printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n",
366 timeout);
367 }
368
369 if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT"))
370 {
371 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
372 ENABLE_W83877F_PORT);
373 rc = -EIO;
374 goto err_out;
375 }
376
377 if (!request_region(WDT_PING, 1, "W8387FF WDT"))
378 {
379 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
380 WDT_PING);
381 rc = -EIO;
382 goto err_out_region1;
383 }
384
385 init_timer(&timer);
386 timer.function = wdt_timer_ping;
387 timer.data = 0;
388
389 rc = misc_register(&wdt_miscdev);
390 if (rc)
391 {
392 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
393 wdt_miscdev.minor, rc);
394 goto err_out_region2;
395 }
396
397 rc = register_reboot_notifier(&wdt_notifier);
398 if (rc)
399 {
400 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
401 rc);
402 goto err_out_miscdev;
403 }
404
405 printk(KERN_INFO PFX "WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n",
406 timeout, nowayout);
407
408 return 0;
409
410err_out_miscdev:
411 misc_deregister(&wdt_miscdev);
412err_out_region2:
413 release_region(WDT_PING,1);
414err_out_region1:
415 release_region(ENABLE_W83877F_PORT,2);
416err_out:
417 return rc;
418}
419
420module_init(w83877f_wdt_init);
421module_exit(w83877f_wdt_unload);
422
423MODULE_AUTHOR("Scott and Bill Jennings");
424MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip");
425MODULE_LICENSE("GPL");
426MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);