[PATCH 13/13] drivers/watchdog: use USB API functions rather than constants
[linux-2.6.git] / drivers / watchdog / w83877f_wdt.c
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
27  *                            the driver offers
28  *                            added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS,
29  *                            WDIOC_SETTIMEOUT,
30  *                            WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls
31  *           09/8 - 2003      [wim@iguana.be] cleanup of trailing spaces
32  *                            added extra printk's for startup problems
33  *                            use module_param
34  *                            made timeout (the emulated heartbeat) a
35  *                            module_param
36  *                            made the keepalive ping an internal subroutine
37  *
38  *  This WDT driver is different from most other Linux WDT
39  *  drivers in that the driver will ping the watchdog by itself,
40  *  because this particular WDT has a very short timeout (1.6
41  *  seconds) and it would be insane to count on any userspace
42  *  daemon always getting scheduled within that time frame.
43  */
44
45 #include <linux/module.h>
46 #include <linux/moduleparam.h>
47 #include <linux/types.h>
48 #include <linux/timer.h>
49 #include <linux/jiffies.h>
50 #include <linux/miscdevice.h>
51 #include <linux/watchdog.h>
52 #include <linux/fs.h>
53 #include <linux/ioport.h>
54 #include <linux/notifier.h>
55 #include <linux/reboot.h>
56 #include <linux/init.h>
57 #include <linux/io.h>
58 #include <linux/uaccess.h>
59 #include <asm/system.h>
60
61 #define OUR_NAME "w83877f_wdt"
62 #define PFX OUR_NAME ": "
63
64 #define ENABLE_W83877F_PORT 0x3F0
65 #define ENABLE_W83877F 0x87
66 #define DISABLE_W83877F 0xAA
67 #define WDT_PING 0x443
68 #define WDT_REGISTER 0x14
69 #define WDT_ENABLE 0x9C
70 #define WDT_DISABLE 0x8C
71
72 /*
73  * The W83877F seems to be fixed at 1.6s timeout (at least on the
74  * EMACS PC-104 board I'm using). If we reset the watchdog every
75  * ~250ms we should be safe.  */
76
77 #define WDT_INTERVAL (HZ/4+1)
78
79 /*
80  * We must not require too good response from the userspace daemon.
81  * Here we require the userspace daemon to send us a heartbeat
82  * char to /dev/watchdog every 30 seconds.
83  */
84
85 #define WATCHDOG_TIMEOUT 30            /* 30 sec default timeout */
86 /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
87 static int timeout = WATCHDOG_TIMEOUT;
88 module_param(timeout, int, 0);
89 MODULE_PARM_DESC(timeout,
90         "Watchdog timeout in seconds. (1<=timeout<=3600, default="
91                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
92
93
94 static int nowayout = WATCHDOG_NOWAYOUT;
95 module_param(nowayout, int, 0);
96 MODULE_PARM_DESC(nowayout,
97                 "Watchdog cannot be stopped once started (default="
98                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
99
100 static void wdt_timer_ping(unsigned long);
101 static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0);
102 static unsigned long next_heartbeat;
103 static unsigned long wdt_is_open;
104 static char wdt_expect_close;
105 static DEFINE_SPINLOCK(wdt_spinlock);
106
107 /*
108  *      Whack the dog
109  */
110
111 static void wdt_timer_ping(unsigned long data)
112 {
113         /* If we got a heartbeat pulse within the WDT_US_INTERVAL
114          * we agree to ping the WDT
115          */
116         if (time_before(jiffies, next_heartbeat)) {
117                 /* Ping the WDT */
118                 spin_lock(&wdt_spinlock);
119
120                 /* Ping the WDT by reading from WDT_PING */
121                 inb_p(WDT_PING);
122
123                 /* Re-set the timer interval */
124                 mod_timer(&timer, jiffies + WDT_INTERVAL);
125
126                 spin_unlock(&wdt_spinlock);
127
128         } else
129                 printk(KERN_WARNING PFX
130                         "Heartbeat lost! Will not ping the watchdog\n");
131 }
132
133 /*
134  * Utility routines
135  */
136
137 static void wdt_change(int writeval)
138 {
139         unsigned long flags;
140         spin_lock_irqsave(&wdt_spinlock, flags);
141
142         /* buy some time */
143         inb_p(WDT_PING);
144
145         /* make W83877F available */
146         outb_p(ENABLE_W83877F,  ENABLE_W83877F_PORT);
147         outb_p(ENABLE_W83877F,  ENABLE_W83877F_PORT);
148
149         /* enable watchdog */
150         outb_p(WDT_REGISTER,    ENABLE_W83877F_PORT);
151         outb_p(writeval,        ENABLE_W83877F_PORT+1);
152
153         /* lock the W8387FF away */
154         outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT);
155
156         spin_unlock_irqrestore(&wdt_spinlock, flags);
157 }
158
159 static void wdt_startup(void)
160 {
161         next_heartbeat = jiffies + (timeout * HZ);
162
163         /* Start the timer */
164         mod_timer(&timer, jiffies + WDT_INTERVAL);
165
166         wdt_change(WDT_ENABLE);
167
168         printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
169 }
170
171 static 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
181 static void wdt_keepalive(void)
182 {
183         /* user land ping */
184         next_heartbeat = jiffies + (timeout * HZ);
185 }
186
187 /*
188  * /dev/watchdog handling
189  */
190
191 static ssize_t fop_write(struct file *file, const char __user *buf,
192                                                 size_t count, loff_t *ppos)
193 {
194         /* See if we got the magic character 'V' and reload the timer */
195         if (count) {
196                 if (!nowayout) {
197                         size_t ofs;
198
199                         /* note: just in case someone wrote the magic
200                            character five months ago... */
201                         wdt_expect_close = 0;
202
203                         /* scan to see whether or not we got the
204                            magic character */
205                         for (ofs = 0; ofs != count; ofs++) {
206                                 char c;
207                                 if (get_user(c, buf + ofs))
208                                         return -EFAULT;
209                                 if (c == 'V')
210                                         wdt_expect_close = 42;
211                         }
212                 }
213
214                 /* someone wrote to us, we should restart timer */
215                 wdt_keepalive();
216         }
217         return count;
218 }
219
220 static int fop_open(struct inode *inode, struct file *file)
221 {
222         /* Just in case we're already talking to someone... */
223         if (test_and_set_bit(0, &wdt_is_open))
224                 return -EBUSY;
225
226         /* Good, fire up the show */
227         wdt_startup();
228         return nonseekable_open(inode, file);
229 }
230
231 static int fop_close(struct inode *inode, struct file *file)
232 {
233         if (wdt_expect_close == 42)
234                 wdt_turnoff();
235         else {
236                 del_timer(&timer);
237                 printk(KERN_CRIT PFX
238                   "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
245 static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
246 {
247         void __user *argp = (void __user *)arg;
248         int __user *p = argp;
249         static const struct watchdog_info ident = {
250                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
251                                                         | WDIOF_MAGICCLOSE,
252                 .firmware_version = 1,
253                 .identity = "W83877F",
254         };
255
256         switch (cmd) {
257         case WDIOC_GETSUPPORT:
258                 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
259         case WDIOC_GETSTATUS:
260         case WDIOC_GETBOOTSTATUS:
261                 return put_user(0, p);
262         case WDIOC_SETOPTIONS:
263         {
264                 int new_options, retval = -EINVAL;
265
266                 if (get_user(new_options, p))
267                         return -EFAULT;
268
269                 if (new_options & WDIOS_DISABLECARD) {
270                         wdt_turnoff();
271                         retval = 0;
272                 }
273
274                 if (new_options & WDIOS_ENABLECARD) {
275                         wdt_startup();
276                         retval = 0;
277                 }
278
279                 return retval;
280         }
281         case WDIOC_KEEPALIVE:
282                 wdt_keepalive();
283                 return 0;
284         case WDIOC_SETTIMEOUT:
285         {
286                 int new_timeout;
287
288                 if (get_user(new_timeout, p))
289                         return -EFAULT;
290
291                 /* arbitrary upper limit */
292                 if (new_timeout < 1 || new_timeout > 3600)
293                         return -EINVAL;
294
295                 timeout = new_timeout;
296                 wdt_keepalive();
297                 /* Fall through */
298         }
299         case WDIOC_GETTIMEOUT:
300                 return put_user(timeout, p);
301         default:
302                 return -ENOTTY;
303         }
304 }
305
306 static const struct file_operations wdt_fops = {
307         .owner          = THIS_MODULE,
308         .llseek         = no_llseek,
309         .write          = fop_write,
310         .open           = fop_open,
311         .release        = fop_close,
312         .unlocked_ioctl = fop_ioctl,
313 };
314
315 static struct miscdevice wdt_miscdev = {
316         .minor  = WATCHDOG_MINOR,
317         .name   = "watchdog",
318         .fops   = &wdt_fops,
319 };
320
321 /*
322  *      Notifier for system down
323  */
324
325 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
326         void *unused)
327 {
328         if (code == SYS_DOWN || code == SYS_HALT)
329                 wdt_turnoff();
330         return NOTIFY_DONE;
331 }
332
333 /*
334  *      The WDT needs to learn about soft shutdowns in order to
335  *      turn the timebomb registers off.
336  */
337
338 static struct notifier_block wdt_notifier = {
339         .notifier_call = wdt_notify_sys,
340 };
341
342 static void __exit w83877f_wdt_unload(void)
343 {
344         wdt_turnoff();
345
346         /* Deregister */
347         misc_deregister(&wdt_miscdev);
348
349         unregister_reboot_notifier(&wdt_notifier);
350         release_region(WDT_PING, 1);
351         release_region(ENABLE_W83877F_PORT, 2);
352 }
353
354 static int __init w83877f_wdt_init(void)
355 {
356         int rc = -EBUSY;
357
358         if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */
359                 timeout = WATCHDOG_TIMEOUT;
360                 printk(KERN_INFO PFX
361                         "timeout value must be 1 <= x <= 3600, using %d\n",
362                                                         timeout);
363         }
364
365         if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) {
366                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
367                         ENABLE_W83877F_PORT);
368                 rc = -EIO;
369                 goto err_out;
370         }
371
372         if (!request_region(WDT_PING, 1, "W8387FF WDT")) {
373                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
374                         WDT_PING);
375                 rc = -EIO;
376                 goto err_out_region1;
377         }
378
379         rc = register_reboot_notifier(&wdt_notifier);
380         if (rc) {
381                 printk(KERN_ERR PFX
382                         "cannot register reboot notifier (err=%d)\n", rc);
383                 goto err_out_region2;
384         }
385
386         rc = misc_register(&wdt_miscdev);
387         if (rc) {
388                 printk(KERN_ERR PFX
389                         "cannot register miscdev on minor=%d (err=%d)\n",
390                                                         wdt_miscdev.minor, rc);
391                 goto err_out_reboot;
392         }
393
394         printk(KERN_INFO PFX
395           "WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n",
396                 timeout, nowayout);
397
398         return 0;
399
400 err_out_reboot:
401         unregister_reboot_notifier(&wdt_notifier);
402 err_out_region2:
403         release_region(WDT_PING, 1);
404 err_out_region1:
405         release_region(ENABLE_W83877F_PORT, 2);
406 err_out:
407         return rc;
408 }
409
410 module_init(w83877f_wdt_init);
411 module_exit(w83877f_wdt_unload);
412
413 MODULE_AUTHOR("Scott and Bill Jennings");
414 MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip");
415 MODULE_LICENSE("GPL");
416 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);