[WATCHDOG] Kconfig+Makefile-clean2
[linux-2.6] / drivers / char / watchdog / sbc60xxwdt.c
1 /*
2  *      60xx Single Board Computer Watchdog Timer driver for Linux 2.2.x
3  *
4  *      Based on acquirewdt.c by Alan Cox.
5  *
6  *      This program is free software; you can redistribute it and/or
7  *      modify it under the terms of the GNU General Public License
8  *      as published by the Free Software Foundation; either version
9  *      2 of the License, or (at your option) any later version.
10  *
11  *      The author does NOT admit liability nor provide warranty for
12  *      any of this software. This material is provided "AS-IS" in
13  *      the hope that it may be useful for others.
14  *
15  *      (c) Copyright 2000    Jakob Oestergaard <jakob@unthought.net>
16  *
17  *           12/4 - 2000      [Initial revision]
18  *           25/4 - 2000      Added /dev/watchdog support
19  *           09/5 - 2001      [smj@oro.net] fixed fop_write to "return 1" on success
20  *           12/4 - 2002      [rob@osinvestor.com] eliminate fop_read
21  *                            fix possible wdt_is_open race
22  *                            add CONFIG_WATCHDOG_NOWAYOUT support
23  *                            remove lock_kernel/unlock_kernel pairs
24  *                            added KERN_* to printk's
25  *                            got rid of extraneous comments
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  *                            use module_param
31  *                            made timeout (the emulated heartbeat) a module_param
32  *                            made the keepalive ping an internal subroutine
33  *                            made wdt_stop and wdt_start module params
34  *                            added extra printk's for startup problems
35  *                            added MODULE_AUTHOR and MODULE_DESCRIPTION info
36  *
37  *
38  *  This WDT driver is different from the other Linux WDT
39  *  drivers in the following ways:
40  *  *)  The driver will ping the watchdog by itself, because this
41  *      particular WDT has a very short timeout (one second) and it
42  *      would be insane to count on any userspace daemon always
43  *      getting scheduled within that time frame.
44  *
45  */
46
47 #include <linux/module.h>
48 #include <linux/moduleparam.h>
49 #include <linux/types.h>
50 #include <linux/timer.h>
51 #include <linux/jiffies.h>
52 #include <linux/miscdevice.h>
53 #include <linux/watchdog.h>
54 #include <linux/fs.h>
55 #include <linux/ioport.h>
56 #include <linux/notifier.h>
57 #include <linux/reboot.h>
58 #include <linux/init.h>
59
60 #include <asm/io.h>
61 #include <asm/uaccess.h>
62 #include <asm/system.h>
63
64 #define OUR_NAME "sbc60xxwdt"
65 #define PFX OUR_NAME ": "
66
67 /*
68  * You must set these - The driver cannot probe for the settings
69  */
70
71 static int wdt_stop = 0x45;
72 module_param(wdt_stop, int, 0);
73 MODULE_PARM_DESC(wdt_stop, "SBC60xx WDT 'stop' io port (default 0x45)");
74
75 static int wdt_start = 0x443;
76 module_param(wdt_start, int, 0);
77 MODULE_PARM_DESC(wdt_start, "SBC60xx WDT 'start' io port (default 0x443)");
78
79 /*
80  * The 60xx board can use watchdog timeout values from one second
81  * to several minutes.  The default is one second, so if we reset
82  * the watchdog every ~250ms we should be safe.
83  */
84
85 #define WDT_INTERVAL (HZ/4+1)
86
87 /*
88  * We must not require too good response from the userspace daemon.
89  * Here we require the userspace daemon to send us a heartbeat
90  * char to /dev/watchdog every 30 seconds.
91  * If the daemon pulses us every 25 seconds, we can still afford
92  * a 5 second scheduling delay on the (high priority) daemon. That
93  * should be sufficient for a box under any load.
94  */
95
96 #define WATCHDOG_TIMEOUT 30             /* 30 sec default timeout */
97 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
98 module_param(timeout, int, 0);
99 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
100
101 static int nowayout = WATCHDOG_NOWAYOUT;
102 module_param(nowayout, int, 0);
103 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
104
105 static void wdt_timer_ping(unsigned long);
106 static struct timer_list timer;
107 static unsigned long next_heartbeat;
108 static unsigned long wdt_is_open;
109 static char wdt_expect_close;
110
111 /*
112  *      Whack the dog
113  */
114
115 static void wdt_timer_ping(unsigned long data)
116 {
117         /* If we got a heartbeat pulse within the WDT_US_INTERVAL
118          * we agree to ping the WDT
119          */
120         if(time_before(jiffies, next_heartbeat))
121         {
122                 /* Ping the WDT by reading from wdt_start */
123                 inb_p(wdt_start);
124                 /* Re-set the timer interval */
125                 timer.expires = jiffies + WDT_INTERVAL;
126                 add_timer(&timer);
127         } else {
128                 printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
129         }
130 }
131
132 /*
133  * Utility routines
134  */
135
136 static void wdt_startup(void)
137 {
138         next_heartbeat = jiffies + (timeout * HZ);
139
140         /* Start the timer */
141         timer.expires = jiffies + WDT_INTERVAL;
142         add_timer(&timer);
143         printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
144 }
145
146 static void wdt_turnoff(void)
147 {
148         /* Stop the timer */
149         del_timer(&timer);
150         inb_p(wdt_stop);
151         printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
152 }
153
154 static void wdt_keepalive(void)
155 {
156         /* user land ping */
157         next_heartbeat = jiffies + (timeout * HZ);
158 }
159
160 /*
161  * /dev/watchdog handling
162  */
163
164 static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos)
165 {
166         /* See if we got the magic character 'V' and reload the timer */
167         if(count)
168         {
169                 if (!nowayout)
170                 {
171                         size_t ofs;
172
173                         /* note: just in case someone wrote the magic character
174                          * five months ago... */
175                         wdt_expect_close = 0;
176
177                         /* scan to see whether or not we got the magic character */
178                         for(ofs = 0; ofs != count; ofs++)
179                         {
180                                 char c;
181                                 if(get_user(c, buf+ofs))
182                                         return -EFAULT;
183                                 if(c == 'V')
184                                         wdt_expect_close = 42;
185                         }
186                 }
187
188                 /* Well, anyhow someone wrote to us, we should return that favour */
189                 wdt_keepalive();
190         }
191         return count;
192 }
193
194 static int fop_open(struct inode * inode, struct file * file)
195 {
196         nonseekable_open(inode, file);
197
198         /* Just in case we're already talking to someone... */
199         if(test_and_set_bit(0, &wdt_is_open))
200                 return -EBUSY;
201
202         if (nowayout)
203                 __module_get(THIS_MODULE);
204
205         /* Good, fire up the show */
206         wdt_startup();
207         return 0;
208 }
209
210 static int fop_close(struct inode * inode, struct file * file)
211 {
212         if(wdt_expect_close == 42)
213                 wdt_turnoff();
214         else {
215                 del_timer(&timer);
216                 printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
217         }
218         clear_bit(0, &wdt_is_open);
219         wdt_expect_close = 0;
220         return 0;
221 }
222
223 static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
224         unsigned long arg)
225 {
226         void __user *argp = (void __user *)arg;
227         int __user *p = argp;
228         static struct watchdog_info ident=
229         {
230                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
231                 .firmware_version = 1,
232                 .identity = "SBC60xx",
233         };
234
235         switch(cmd)
236         {
237                 default:
238                         return -ENOIOCTLCMD;
239                 case WDIOC_GETSUPPORT:
240                         return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
241                 case WDIOC_GETSTATUS:
242                 case WDIOC_GETBOOTSTATUS:
243                         return put_user(0, p);
244                 case WDIOC_KEEPALIVE:
245                         wdt_keepalive();
246                         return 0;
247                 case WDIOC_SETOPTIONS:
248                 {
249                         int new_options, retval = -EINVAL;
250
251                         if(get_user(new_options, p))
252                                 return -EFAULT;
253
254                         if(new_options & WDIOS_DISABLECARD) {
255                                 wdt_turnoff();
256                                 retval = 0;
257                         }
258
259                         if(new_options & WDIOS_ENABLECARD) {
260                                 wdt_startup();
261                                 retval = 0;
262                         }
263
264                         return retval;
265                 }
266                 case WDIOC_SETTIMEOUT:
267                 {
268                         int new_timeout;
269
270                         if(get_user(new_timeout, p))
271                                 return -EFAULT;
272
273                         if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */
274                                 return -EINVAL;
275
276                         timeout = new_timeout;
277                         wdt_keepalive();
278                         /* Fall through */
279                 }
280                 case WDIOC_GETTIMEOUT:
281                         return put_user(timeout, p);
282         }
283 }
284
285 static struct file_operations wdt_fops = {
286         .owner          = THIS_MODULE,
287         .llseek         = no_llseek,
288         .write          = fop_write,
289         .open           = fop_open,
290         .release        = fop_close,
291         .ioctl          = fop_ioctl,
292 };
293
294 static struct miscdevice wdt_miscdev = {
295         .minor = WATCHDOG_MINOR,
296         .name = "watchdog",
297         .fops = &wdt_fops,
298 };
299
300 /*
301  *      Notifier for system down
302  */
303
304 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
305         void *unused)
306 {
307         if(code==SYS_DOWN || code==SYS_HALT)
308                 wdt_turnoff();
309         return NOTIFY_DONE;
310 }
311
312 /*
313  *      The WDT needs to learn about soft shutdowns in order to
314  *      turn the timebomb registers off.
315  */
316
317 static struct notifier_block wdt_notifier=
318 {
319         .notifier_call = wdt_notify_sys,
320 };
321
322 static void __exit sbc60xxwdt_unload(void)
323 {
324         wdt_turnoff();
325
326         /* Deregister */
327         misc_deregister(&wdt_miscdev);
328
329         unregister_reboot_notifier(&wdt_notifier);
330         if ((wdt_stop != 0x45) && (wdt_stop != wdt_start))
331                 release_region(wdt_stop,1);
332         release_region(wdt_start,1);
333 }
334
335 static int __init sbc60xxwdt_init(void)
336 {
337         int rc = -EBUSY;
338
339         if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */
340         {
341                 timeout = WATCHDOG_TIMEOUT;
342                 printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n",
343                         timeout);
344         }
345
346         if (!request_region(wdt_start, 1, "SBC 60XX WDT"))
347         {
348                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
349                         wdt_start);
350                 rc = -EIO;
351                 goto err_out;
352         }
353
354         /* We cannot reserve 0x45 - the kernel already has! */
355         if ((wdt_stop != 0x45) && (wdt_stop != wdt_start))
356         {
357                 if (!request_region(wdt_stop, 1, "SBC 60XX WDT"))
358                 {
359                         printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
360                                 wdt_stop);
361                         rc = -EIO;
362                         goto err_out_region1;
363                 }
364         }
365
366         init_timer(&timer);
367         timer.function = wdt_timer_ping;
368         timer.data = 0;
369
370         rc = misc_register(&wdt_miscdev);
371         if (rc)
372         {
373                 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
374                         wdt_miscdev.minor, rc);
375                 goto err_out_region2;
376         }
377
378         rc = register_reboot_notifier(&wdt_notifier);
379         if (rc)
380         {
381                 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
382                         rc);
383                 goto err_out_miscdev;
384         }
385
386         printk(KERN_INFO PFX "WDT driver for 60XX single board computer initialised. timeout=%d sec (nowayout=%d)\n",
387                 timeout, nowayout);
388
389         return 0;
390
391 err_out_miscdev:
392         misc_deregister(&wdt_miscdev);
393 err_out_region2:
394         if ((wdt_stop != 0x45) && (wdt_stop != wdt_start))
395                 release_region(wdt_stop,1);
396 err_out_region1:
397         release_region(wdt_start,1);
398 err_out:
399         return rc;
400 }
401
402 module_init(sbc60xxwdt_init);
403 module_exit(sbc60xxwdt_unload);
404
405 MODULE_AUTHOR("Jakob Oestergaard <jakob@unthought.net>");
406 MODULE_DESCRIPTION("60xx Single Board Computer Watchdog Timer driver");
407 MODULE_LICENSE("GPL");
408 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);