1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Wdt977 0.04: A Watchdog Device for Netwinder W83977AF chip
4 *
5 * (c) Copyright 1998 Rebel.com (Woody Suwalski <woody@netwinder.org>)
6 *
7 * -----------------------
8 *
9 * -----------------------
10 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
11 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
12 * 19-Dec-2001 Woody Suwalski: Netwinder fixes, ioctl interface
13 * 06-Jan-2002 Woody Suwalski: For compatibility, convert all timeouts
14 * from minutes to seconds.
15 * 07-Jul-2003 Daniele Bellucci: Audit return code of misc_register in
16 * nwwatchdog_init.
17 * 25-Oct-2005 Woody Suwalski: Convert addresses to #defs, add spinlocks
18 * remove limitiation to be used on
19 * Netwinders only
20 */
21
22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23
24 #include <linux/module.h>
25 #include <linux/moduleparam.h>
26 #include <linux/types.h>
27 #include <linux/kernel.h>
28 #include <linux/fs.h>
29 #include <linux/miscdevice.h>
30 #include <linux/init.h>
31 #include <linux/ioport.h>
32 #include <linux/watchdog.h>
33 #include <linux/notifier.h>
34 #include <linux/reboot.h>
35 #include <linux/io.h>
36 #include <linux/uaccess.h>
37
38 #include <asm/mach-types.h>
39
40 #define WATCHDOG_VERSION "0.04"
41 #define WATCHDOG_NAME "Wdt977"
42
43 #define IO_INDEX_PORT 0x370 /* on some systems it can be 0x3F0 */
44 #define IO_DATA_PORT (IO_INDEX_PORT + 1)
45
46 #define UNLOCK_DATA 0x87
47 #define LOCK_DATA 0xAA
48 #define DEVICE_REGISTER 0x07
49
50
51 #define DEFAULT_TIMEOUT 60 /* default timeout in seconds */
52
53 static int timeout = DEFAULT_TIMEOUT;
54 static int timeoutM; /* timeout in minutes */
55 static unsigned long timer_alive;
56 static int testmode;
57 static char expect_close;
58 static DEFINE_SPINLOCK(spinlock);
59
60 module_param(timeout, int, 0);
61 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (60..15300, default="
62 __MODULE_STRING(DEFAULT_TIMEOUT) ")");
63 module_param(testmode, int, 0);
64 MODULE_PARM_DESC(testmode, "Watchdog testmode (1 = no reboot), default=0");
65
66 static bool nowayout = WATCHDOG_NOWAYOUT;
67 module_param(nowayout, bool, 0);
68 MODULE_PARM_DESC(nowayout,
69 "Watchdog cannot be stopped once started (default="
70 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
71
72 /*
73 * Start the watchdog
74 */
75
wdt977_start(void)76 static int wdt977_start(void)
77 {
78 unsigned long flags;
79
80 spin_lock_irqsave(&spinlock, flags);
81
82 /* unlock the SuperIO chip */
83 outb_p(UNLOCK_DATA, IO_INDEX_PORT);
84 outb_p(UNLOCK_DATA, IO_INDEX_PORT);
85
86 /* select device Aux2 (device=8) and set watchdog regs F2, F3 and F4
87 * F2 has the timeout in minutes
88 * F3 could be set to the POWER LED blink (with GP17 set to PowerLed)
89 * at timeout, and to reset timer on kbd/mouse activity (not impl.)
90 * F4 is used to just clear the TIMEOUT'ed state (bit 0)
91 */
92 outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
93 outb_p(0x08, IO_DATA_PORT);
94 outb_p(0xF2, IO_INDEX_PORT);
95 outb_p(timeoutM, IO_DATA_PORT);
96 outb_p(0xF3, IO_INDEX_PORT);
97 outb_p(0x00, IO_DATA_PORT); /* another setting is 0E for
98 kbd/mouse/LED */
99 outb_p(0xF4, IO_INDEX_PORT);
100 outb_p(0x00, IO_DATA_PORT);
101
102 /* At last select device Aux1 (dev=7) and set GP16 as a
103 * watchdog output. In test mode watch the bit 1 on F4 to
104 * indicate "triggered"
105 */
106 if (!testmode) {
107 outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
108 outb_p(0x07, IO_DATA_PORT);
109 outb_p(0xE6, IO_INDEX_PORT);
110 outb_p(0x08, IO_DATA_PORT);
111 }
112
113 /* lock the SuperIO chip */
114 outb_p(LOCK_DATA, IO_INDEX_PORT);
115
116 spin_unlock_irqrestore(&spinlock, flags);
117 pr_info("activated\n");
118
119 return 0;
120 }
121
122 /*
123 * Stop the watchdog
124 */
125
wdt977_stop(void)126 static int wdt977_stop(void)
127 {
128 unsigned long flags;
129 spin_lock_irqsave(&spinlock, flags);
130
131 /* unlock the SuperIO chip */
132 outb_p(UNLOCK_DATA, IO_INDEX_PORT);
133 outb_p(UNLOCK_DATA, IO_INDEX_PORT);
134
135 /* select device Aux2 (device=8) and set watchdog regs F2,F3 and F4
136 * F3 is reset to its default state
137 * F4 can clear the TIMEOUT'ed state (bit 0) - back to default
138 * We can not use GP17 as a PowerLed, as we use its usage as a RedLed
139 */
140 outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
141 outb_p(0x08, IO_DATA_PORT);
142 outb_p(0xF2, IO_INDEX_PORT);
143 outb_p(0xFF, IO_DATA_PORT);
144 outb_p(0xF3, IO_INDEX_PORT);
145 outb_p(0x00, IO_DATA_PORT);
146 outb_p(0xF4, IO_INDEX_PORT);
147 outb_p(0x00, IO_DATA_PORT);
148 outb_p(0xF2, IO_INDEX_PORT);
149 outb_p(0x00, IO_DATA_PORT);
150
151 /* at last select device Aux1 (dev=7) and set
152 GP16 as a watchdog output */
153 outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
154 outb_p(0x07, IO_DATA_PORT);
155 outb_p(0xE6, IO_INDEX_PORT);
156 outb_p(0x08, IO_DATA_PORT);
157
158 /* lock the SuperIO chip */
159 outb_p(LOCK_DATA, IO_INDEX_PORT);
160
161 spin_unlock_irqrestore(&spinlock, flags);
162 pr_info("shutdown\n");
163
164 return 0;
165 }
166
167 /*
168 * Send a keepalive ping to the watchdog
169 * This is done by simply re-writing the timeout to reg. 0xF2
170 */
171
wdt977_keepalive(void)172 static int wdt977_keepalive(void)
173 {
174 unsigned long flags;
175 spin_lock_irqsave(&spinlock, flags);
176
177 /* unlock the SuperIO chip */
178 outb_p(UNLOCK_DATA, IO_INDEX_PORT);
179 outb_p(UNLOCK_DATA, IO_INDEX_PORT);
180
181 /* select device Aux2 (device=8) and kicks watchdog reg F2 */
182 /* F2 has the timeout in minutes */
183 outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
184 outb_p(0x08, IO_DATA_PORT);
185 outb_p(0xF2, IO_INDEX_PORT);
186 outb_p(timeoutM, IO_DATA_PORT);
187
188 /* lock the SuperIO chip */
189 outb_p(LOCK_DATA, IO_INDEX_PORT);
190 spin_unlock_irqrestore(&spinlock, flags);
191
192 return 0;
193 }
194
195 /*
196 * Set the watchdog timeout value
197 */
198
wdt977_set_timeout(int t)199 static int wdt977_set_timeout(int t)
200 {
201 int tmrval;
202
203 /* convert seconds to minutes, rounding up */
204 tmrval = (t + 59) / 60;
205
206 if (machine_is_netwinder()) {
207 /* we have a hw bug somewhere, so each 977 minute is actually
208 * only 30sec. This limits the max timeout to half of device
209 * max of 255 minutes...
210 */
211 tmrval += tmrval;
212 }
213
214 if (tmrval < 1 || tmrval > 255)
215 return -EINVAL;
216
217 /* timeout is the timeout in seconds, timeoutM is
218 the timeout in minutes) */
219 timeout = t;
220 timeoutM = tmrval;
221 return 0;
222 }
223
224 /*
225 * Get the watchdog status
226 */
227
wdt977_get_status(int * status)228 static int wdt977_get_status(int *status)
229 {
230 int new_status;
231 unsigned long flags;
232
233 spin_lock_irqsave(&spinlock, flags);
234
235 /* unlock the SuperIO chip */
236 outb_p(UNLOCK_DATA, IO_INDEX_PORT);
237 outb_p(UNLOCK_DATA, IO_INDEX_PORT);
238
239 /* select device Aux2 (device=8) and read watchdog reg F4 */
240 outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
241 outb_p(0x08, IO_DATA_PORT);
242 outb_p(0xF4, IO_INDEX_PORT);
243 new_status = inb_p(IO_DATA_PORT);
244
245 /* lock the SuperIO chip */
246 outb_p(LOCK_DATA, IO_INDEX_PORT);
247
248 spin_unlock_irqrestore(&spinlock, flags);
249
250 *status = 0;
251 if (new_status & 1)
252 *status |= WDIOF_CARDRESET;
253
254 return 0;
255 }
256
257
258 /*
259 * /dev/watchdog handling
260 */
261
wdt977_open(struct inode * inode,struct file * file)262 static int wdt977_open(struct inode *inode, struct file *file)
263 {
264 /* If the watchdog is alive we don't need to start it again */
265 if (test_and_set_bit(0, &timer_alive))
266 return -EBUSY;
267
268 if (nowayout)
269 __module_get(THIS_MODULE);
270
271 wdt977_start();
272 return stream_open(inode, file);
273 }
274
wdt977_release(struct inode * inode,struct file * file)275 static int wdt977_release(struct inode *inode, struct file *file)
276 {
277 /*
278 * Shut off the timer.
279 * Lock it in if it's a module and we set nowayout
280 */
281 if (expect_close == 42) {
282 wdt977_stop();
283 clear_bit(0, &timer_alive);
284 } else {
285 wdt977_keepalive();
286 pr_crit("Unexpected close, not stopping watchdog!\n");
287 }
288 expect_close = 0;
289 return 0;
290 }
291
292
293 /*
294 * wdt977_write:
295 * @file: file handle to the watchdog
296 * @buf: buffer to write (unused as data does not matter here
297 * @count: count of bytes
298 * @ppos: pointer to the position to write. No seeks allowed
299 *
300 * A write to a watchdog device is defined as a keepalive signal. Any
301 * write of data will do, as we we don't define content meaning.
302 */
303
wdt977_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)304 static ssize_t wdt977_write(struct file *file, const char __user *buf,
305 size_t count, loff_t *ppos)
306 {
307 if (count) {
308 if (!nowayout) {
309 size_t i;
310
311 /* In case it was set long ago */
312 expect_close = 0;
313
314 for (i = 0; i != count; i++) {
315 char c;
316 if (get_user(c, buf + i))
317 return -EFAULT;
318 if (c == 'V')
319 expect_close = 42;
320 }
321 }
322
323 /* someone wrote to us, we should restart timer */
324 wdt977_keepalive();
325 }
326 return count;
327 }
328
329 static const struct watchdog_info ident = {
330 .options = WDIOF_SETTIMEOUT |
331 WDIOF_MAGICCLOSE |
332 WDIOF_KEEPALIVEPING,
333 .firmware_version = 1,
334 .identity = WATCHDOG_NAME,
335 };
336
337 /*
338 * wdt977_ioctl:
339 * @inode: inode of the device
340 * @file: file handle to the device
341 * @cmd: watchdog command
342 * @arg: argument pointer
343 *
344 * The watchdog API defines a common set of functions for all watchdogs
345 * according to their available features.
346 */
347
wdt977_ioctl(struct file * file,unsigned int cmd,unsigned long arg)348 static long wdt977_ioctl(struct file *file, unsigned int cmd,
349 unsigned long arg)
350 {
351 int status;
352 int new_options, retval = -EINVAL;
353 int new_timeout;
354 union {
355 struct watchdog_info __user *ident;
356 int __user *i;
357 } uarg;
358
359 uarg.i = (int __user *)arg;
360
361 switch (cmd) {
362 case WDIOC_GETSUPPORT:
363 return copy_to_user(uarg.ident, &ident,
364 sizeof(ident)) ? -EFAULT : 0;
365
366 case WDIOC_GETSTATUS:
367 wdt977_get_status(&status);
368 return put_user(status, uarg.i);
369
370 case WDIOC_GETBOOTSTATUS:
371 return put_user(0, uarg.i);
372
373 case WDIOC_SETOPTIONS:
374 if (get_user(new_options, uarg.i))
375 return -EFAULT;
376
377 if (new_options & WDIOS_DISABLECARD) {
378 wdt977_stop();
379 retval = 0;
380 }
381
382 if (new_options & WDIOS_ENABLECARD) {
383 wdt977_start();
384 retval = 0;
385 }
386
387 return retval;
388
389 case WDIOC_KEEPALIVE:
390 wdt977_keepalive();
391 return 0;
392
393 case WDIOC_SETTIMEOUT:
394 if (get_user(new_timeout, uarg.i))
395 return -EFAULT;
396
397 if (wdt977_set_timeout(new_timeout))
398 return -EINVAL;
399
400 wdt977_keepalive();
401 fallthrough;
402
403 case WDIOC_GETTIMEOUT:
404 return put_user(timeout, uarg.i);
405
406 default:
407 return -ENOTTY;
408
409 }
410 }
411
wdt977_notify_sys(struct notifier_block * this,unsigned long code,void * unused)412 static int wdt977_notify_sys(struct notifier_block *this, unsigned long code,
413 void *unused)
414 {
415 if (code == SYS_DOWN || code == SYS_HALT)
416 wdt977_stop();
417 return NOTIFY_DONE;
418 }
419
420 static const struct file_operations wdt977_fops = {
421 .owner = THIS_MODULE,
422 .write = wdt977_write,
423 .unlocked_ioctl = wdt977_ioctl,
424 .compat_ioctl = compat_ptr_ioctl,
425 .open = wdt977_open,
426 .release = wdt977_release,
427 };
428
429 static struct miscdevice wdt977_miscdev = {
430 .minor = WATCHDOG_MINOR,
431 .name = "watchdog",
432 .fops = &wdt977_fops,
433 };
434
435 static struct notifier_block wdt977_notifier = {
436 .notifier_call = wdt977_notify_sys,
437 };
438
wd977_init(void)439 static int __init wd977_init(void)
440 {
441 int rc;
442
443 pr_info("driver v%s\n", WATCHDOG_VERSION);
444
445 /* Check that the timeout value is within its range;
446 if not reset to the default */
447 if (wdt977_set_timeout(timeout)) {
448 wdt977_set_timeout(DEFAULT_TIMEOUT);
449 pr_info("timeout value must be 60 < timeout < 15300, using %d\n",
450 DEFAULT_TIMEOUT);
451 }
452
453 /* on Netwinder the IOports are already reserved by
454 * arch/arm/mach-footbridge/netwinder-hw.c
455 */
456 if (!machine_is_netwinder()) {
457 if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME)) {
458 pr_err("I/O address 0x%04x already in use\n",
459 IO_INDEX_PORT);
460 rc = -EIO;
461 goto err_out;
462 }
463 }
464
465 rc = register_reboot_notifier(&wdt977_notifier);
466 if (rc) {
467 pr_err("cannot register reboot notifier (err=%d)\n", rc);
468 goto err_out_region;
469 }
470
471 rc = misc_register(&wdt977_miscdev);
472 if (rc) {
473 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
474 wdt977_miscdev.minor, rc);
475 goto err_out_reboot;
476 }
477
478 pr_info("initialized. timeout=%d sec (nowayout=%d, testmode=%i)\n",
479 timeout, nowayout, testmode);
480
481 return 0;
482
483 err_out_reboot:
484 unregister_reboot_notifier(&wdt977_notifier);
485 err_out_region:
486 if (!machine_is_netwinder())
487 release_region(IO_INDEX_PORT, 2);
488 err_out:
489 return rc;
490 }
491
wd977_exit(void)492 static void __exit wd977_exit(void)
493 {
494 wdt977_stop();
495 misc_deregister(&wdt977_miscdev);
496 unregister_reboot_notifier(&wdt977_notifier);
497 release_region(IO_INDEX_PORT, 2);
498 }
499
500 module_init(wd977_init);
501 module_exit(wd977_exit);
502
503 MODULE_AUTHOR("Woody Suwalski <woodys@xandros.com>");
504 MODULE_DESCRIPTION("W83977AF Watchdog driver");
505 MODULE_LICENSE("GPL");
506