1 /*
2 * w83697hf/hg WDT driver
3 *
4 * (c) Copyright 2006 Samuel Tardieu <sam@rfc1149.net>
5 * (c) Copyright 2006 Marcus Junker <junker@anduras.de>
6 *
7 * Based on w83627hf_wdt.c which is based on advantechwdt.c
8 * which is based on wdt.c.
9 * Original copyright messages:
10 *
11 * (c) Copyright 2003 Pádraig Brady <P@draigBrady.com>
12 *
13 * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
14 *
15 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
16 * All Rights Reserved.
17 *
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
22 *
23 * Neither Marcus Junker nor ANDURAS AG admit liability nor provide
24 * warranty for any of this software. This material is provided
25 * "AS-IS" and at no charge.
26 */
27
28 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29
30 #include <linux/module.h>
31 #include <linux/moduleparam.h>
32 #include <linux/types.h>
33 #include <linux/miscdevice.h>
34 #include <linux/watchdog.h>
35 #include <linux/fs.h>
36 #include <linux/ioport.h>
37 #include <linux/notifier.h>
38 #include <linux/reboot.h>
39 #include <linux/init.h>
40 #include <linux/spinlock.h>
41 #include <linux/io.h>
42 #include <linux/uaccess.h>
43
44
45 #define WATCHDOG_NAME "w83697hf/hg WDT"
46 #define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
47 #define WATCHDOG_EARLY_DISABLE 1 /* Disable until userland kicks in */
48
49 static unsigned long wdt_is_open;
50 static char expect_close;
51 static DEFINE_SPINLOCK(io_lock);
52
53 /* You must set this - there is no sane way to probe for this board. */
54 static int wdt_io = 0x2e;
55 module_param(wdt_io, int, 0);
56 MODULE_PARM_DESC(wdt_io,
57 "w83697hf/hg WDT io port (default 0x2e, 0 = autodetect)");
58
59 static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
60 module_param(timeout, int, 0);
61 MODULE_PARM_DESC(timeout,
62 "Watchdog timeout in seconds. 1<= timeout <=255 (default="
63 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
64
65 static bool nowayout = WATCHDOG_NOWAYOUT;
66 module_param(nowayout, bool, 0);
67 MODULE_PARM_DESC(nowayout,
68 "Watchdog cannot be stopped once started (default="
69 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
70
71 static int early_disable = WATCHDOG_EARLY_DISABLE;
72 module_param(early_disable, int, 0);
73 MODULE_PARM_DESC(early_disable,
74 "Watchdog gets disabled at boot time (default="
75 __MODULE_STRING(WATCHDOG_EARLY_DISABLE) ")");
76
77 /*
78 * Kernel methods.
79 */
80
81 #define W83697HF_EFER (wdt_io + 0) /* Extended Function Enable Register */
82 #define W83697HF_EFIR (wdt_io + 0) /* Extended Function Index Register
83 (same as EFER) */
84 #define W83697HF_EFDR (wdt_io + 1) /* Extended Function Data Register */
85
w83697hf_unlock(void)86 static inline void w83697hf_unlock(void)
87 {
88 outb_p(0x87, W83697HF_EFER); /* Enter extended function mode */
89 outb_p(0x87, W83697HF_EFER); /* Again according to manual */
90 }
91
w83697hf_lock(void)92 static inline void w83697hf_lock(void)
93 {
94 outb_p(0xAA, W83697HF_EFER); /* Leave extended function mode */
95 }
96
97 /*
98 * The three functions w83697hf_get_reg(), w83697hf_set_reg() and
99 * w83697hf_write_timeout() must be called with the device unlocked.
100 */
101
w83697hf_get_reg(unsigned char reg)102 static unsigned char w83697hf_get_reg(unsigned char reg)
103 {
104 outb_p(reg, W83697HF_EFIR);
105 return inb_p(W83697HF_EFDR);
106 }
107
w83697hf_set_reg(unsigned char reg,unsigned char data)108 static void w83697hf_set_reg(unsigned char reg, unsigned char data)
109 {
110 outb_p(reg, W83697HF_EFIR);
111 outb_p(data, W83697HF_EFDR);
112 }
113
w83697hf_write_timeout(int timeout)114 static void w83697hf_write_timeout(int timeout)
115 {
116 /* Write Timeout counter to CRF4 */
117 w83697hf_set_reg(0xF4, timeout);
118 }
119
w83697hf_select_wdt(void)120 static void w83697hf_select_wdt(void)
121 {
122 w83697hf_unlock();
123 w83697hf_set_reg(0x07, 0x08); /* Switch to logic device 8 (GPIO2) */
124 }
125
w83697hf_deselect_wdt(void)126 static inline void w83697hf_deselect_wdt(void)
127 {
128 w83697hf_lock();
129 }
130
w83697hf_init(void)131 static void w83697hf_init(void)
132 {
133 unsigned char bbuf;
134
135 w83697hf_select_wdt();
136
137 bbuf = w83697hf_get_reg(0x29);
138 bbuf &= ~0x60;
139 bbuf |= 0x20;
140
141 /* Set pin 119 to WDTO# mode (= CR29, WDT0) */
142 w83697hf_set_reg(0x29, bbuf);
143
144 bbuf = w83697hf_get_reg(0xF3);
145 bbuf &= ~0x04;
146 w83697hf_set_reg(0xF3, bbuf); /* Count mode is seconds */
147
148 w83697hf_deselect_wdt();
149 }
150
wdt_ping(void)151 static void wdt_ping(void)
152 {
153 spin_lock(&io_lock);
154 w83697hf_select_wdt();
155
156 w83697hf_write_timeout(timeout);
157
158 w83697hf_deselect_wdt();
159 spin_unlock(&io_lock);
160 }
161
wdt_enable(void)162 static void wdt_enable(void)
163 {
164 spin_lock(&io_lock);
165 w83697hf_select_wdt();
166
167 w83697hf_write_timeout(timeout);
168 w83697hf_set_reg(0x30, 1); /* Enable timer */
169
170 w83697hf_deselect_wdt();
171 spin_unlock(&io_lock);
172 }
173
wdt_disable(void)174 static void wdt_disable(void)
175 {
176 spin_lock(&io_lock);
177 w83697hf_select_wdt();
178
179 w83697hf_set_reg(0x30, 0); /* Disable timer */
180 w83697hf_write_timeout(0);
181
182 w83697hf_deselect_wdt();
183 spin_unlock(&io_lock);
184 }
185
wdt_running(void)186 static unsigned char wdt_running(void)
187 {
188 unsigned char t;
189
190 spin_lock(&io_lock);
191 w83697hf_select_wdt();
192
193 t = w83697hf_get_reg(0xF4); /* Read timer */
194
195 w83697hf_deselect_wdt();
196 spin_unlock(&io_lock);
197
198 return t;
199 }
200
wdt_set_heartbeat(int t)201 static int wdt_set_heartbeat(int t)
202 {
203 if (t < 1 || t > 255)
204 return -EINVAL;
205
206 timeout = t;
207 return 0;
208 }
209
wdt_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)210 static ssize_t wdt_write(struct file *file, const char __user *buf,
211 size_t count, loff_t *ppos)
212 {
213 if (count) {
214 if (!nowayout) {
215 size_t i;
216
217 expect_close = 0;
218
219 for (i = 0; i != count; i++) {
220 char c;
221 if (get_user(c, buf + i))
222 return -EFAULT;
223 if (c == 'V')
224 expect_close = 42;
225 }
226 }
227 wdt_ping();
228 }
229 return count;
230 }
231
wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)232 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
233 {
234 void __user *argp = (void __user *)arg;
235 int __user *p = argp;
236 int new_timeout;
237 static const struct watchdog_info ident = {
238 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
239 | WDIOF_MAGICCLOSE,
240 .firmware_version = 1,
241 .identity = "W83697HF WDT",
242 };
243
244 switch (cmd) {
245 case WDIOC_GETSUPPORT:
246 if (copy_to_user(argp, &ident, sizeof(ident)))
247 return -EFAULT;
248 break;
249
250 case WDIOC_GETSTATUS:
251 case WDIOC_GETBOOTSTATUS:
252 return put_user(0, p);
253
254 case WDIOC_SETOPTIONS:
255 {
256 int options, retval = -EINVAL;
257
258 if (get_user(options, p))
259 return -EFAULT;
260
261 if (options & WDIOS_DISABLECARD) {
262 wdt_disable();
263 retval = 0;
264 }
265
266 if (options & WDIOS_ENABLECARD) {
267 wdt_enable();
268 retval = 0;
269 }
270
271 return retval;
272 }
273
274 case WDIOC_KEEPALIVE:
275 wdt_ping();
276 break;
277
278 case WDIOC_SETTIMEOUT:
279 if (get_user(new_timeout, p))
280 return -EFAULT;
281 if (wdt_set_heartbeat(new_timeout))
282 return -EINVAL;
283 wdt_ping();
284 /* Fall */
285
286 case WDIOC_GETTIMEOUT:
287 return put_user(timeout, p);
288
289 default:
290 return -ENOTTY;
291 }
292 return 0;
293 }
294
wdt_open(struct inode * inode,struct file * file)295 static int wdt_open(struct inode *inode, struct file *file)
296 {
297 if (test_and_set_bit(0, &wdt_is_open))
298 return -EBUSY;
299 /*
300 * Activate
301 */
302
303 wdt_enable();
304 return nonseekable_open(inode, file);
305 }
306
wdt_close(struct inode * inode,struct file * file)307 static int wdt_close(struct inode *inode, struct file *file)
308 {
309 if (expect_close == 42)
310 wdt_disable();
311 else {
312 pr_crit("Unexpected close, not stopping watchdog!\n");
313 wdt_ping();
314 }
315 expect_close = 0;
316 clear_bit(0, &wdt_is_open);
317 return 0;
318 }
319
320 /*
321 * Notifier for system down
322 */
323
wdt_notify_sys(struct notifier_block * this,unsigned long code,void * unused)324 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
325 void *unused)
326 {
327 if (code == SYS_DOWN || code == SYS_HALT)
328 wdt_disable(); /* Turn the WDT off */
329
330 return NOTIFY_DONE;
331 }
332
333 /*
334 * Kernel Interfaces
335 */
336
337 static const struct file_operations wdt_fops = {
338 .owner = THIS_MODULE,
339 .llseek = no_llseek,
340 .write = wdt_write,
341 .unlocked_ioctl = wdt_ioctl,
342 .open = wdt_open,
343 .release = wdt_close,
344 };
345
346 static struct miscdevice wdt_miscdev = {
347 .minor = WATCHDOG_MINOR,
348 .name = "watchdog",
349 .fops = &wdt_fops,
350 };
351
352 /*
353 * The WDT needs to learn about soft shutdowns in order to
354 * turn the timebomb registers off.
355 */
356
357 static struct notifier_block wdt_notifier = {
358 .notifier_call = wdt_notify_sys,
359 };
360
w83697hf_check_wdt(void)361 static int w83697hf_check_wdt(void)
362 {
363 if (!request_region(wdt_io, 2, WATCHDOG_NAME)) {
364 pr_err("I/O address 0x%x already in use\n", wdt_io);
365 return -EIO;
366 }
367
368 pr_debug("Looking for watchdog at address 0x%x\n", wdt_io);
369 w83697hf_unlock();
370 if (w83697hf_get_reg(0x20) == 0x60) {
371 pr_info("watchdog found at address 0x%x\n", wdt_io);
372 w83697hf_lock();
373 return 0;
374 }
375 /* Reprotect in case it was a compatible device */
376 w83697hf_lock();
377
378 pr_info("watchdog not found at address 0x%x\n", wdt_io);
379 release_region(wdt_io, 2);
380 return -EIO;
381 }
382
383 static int w83697hf_ioports[] = { 0x2e, 0x4e, 0x00 };
384
wdt_init(void)385 static int __init wdt_init(void)
386 {
387 int ret, i, found = 0;
388
389 pr_info("WDT driver for W83697HF/HG initializing\n");
390
391 if (wdt_io == 0) {
392 /* we will autodetect the W83697HF/HG watchdog */
393 for (i = 0; ((!found) && (w83697hf_ioports[i] != 0)); i++) {
394 wdt_io = w83697hf_ioports[i];
395 if (!w83697hf_check_wdt())
396 found++;
397 }
398 } else {
399 if (!w83697hf_check_wdt())
400 found++;
401 }
402
403 if (!found) {
404 pr_err("No W83697HF/HG could be found\n");
405 ret = -EIO;
406 goto out;
407 }
408
409 w83697hf_init();
410 if (early_disable) {
411 if (wdt_running())
412 pr_warn("Stopping previously enabled watchdog until userland kicks in\n");
413 wdt_disable();
414 }
415
416 if (wdt_set_heartbeat(timeout)) {
417 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
418 pr_info("timeout value must be 1 <= timeout <= 255, using %d\n",
419 WATCHDOG_TIMEOUT);
420 }
421
422 ret = register_reboot_notifier(&wdt_notifier);
423 if (ret != 0) {
424 pr_err("cannot register reboot notifier (err=%d)\n", ret);
425 goto unreg_regions;
426 }
427
428 ret = misc_register(&wdt_miscdev);
429 if (ret != 0) {
430 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
431 WATCHDOG_MINOR, ret);
432 goto unreg_reboot;
433 }
434
435 pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
436 timeout, nowayout);
437
438 out:
439 return ret;
440 unreg_reboot:
441 unregister_reboot_notifier(&wdt_notifier);
442 unreg_regions:
443 release_region(wdt_io, 2);
444 goto out;
445 }
446
wdt_exit(void)447 static void __exit wdt_exit(void)
448 {
449 misc_deregister(&wdt_miscdev);
450 unregister_reboot_notifier(&wdt_notifier);
451 release_region(wdt_io, 2);
452 }
453
454 module_init(wdt_init);
455 module_exit(wdt_exit);
456
457 MODULE_LICENSE("GPL");
458 MODULE_AUTHOR("Marcus Junker <junker@anduras.de>, "
459 "Samuel Tardieu <sam@rfc1149.net>");
460 MODULE_DESCRIPTION("w83697hf/hg WDT driver");
461 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
462