1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * W83977F Watchdog Timer Driver for Winbond W83977F I/O Chip |
4 | * |
5 | * (c) Copyright 2005 Jose Goncalves <jose.goncalves@inov.pt> |
6 | * |
7 | * Based on w83877f_wdt.c by Scott Jennings, |
8 | * and wdt977.c by Woody Suwalski |
9 | * |
10 | * ----------------------- |
11 | */ |
12 | |
13 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
14 | |
15 | #include <linux/module.h> |
16 | #include <linux/moduleparam.h> |
17 | #include <linux/types.h> |
18 | #include <linux/kernel.h> |
19 | #include <linux/fs.h> |
20 | #include <linux/miscdevice.h> |
21 | #include <linux/init.h> |
22 | #include <linux/ioport.h> |
23 | #include <linux/watchdog.h> |
24 | #include <linux/notifier.h> |
25 | #include <linux/reboot.h> |
26 | #include <linux/uaccess.h> |
27 | #include <linux/io.h> |
28 | |
29 | |
30 | #define WATCHDOG_VERSION "1.00" |
31 | #define WATCHDOG_NAME "W83977F WDT" |
32 | |
33 | #define IO_INDEX_PORT 0x3F0 |
34 | #define IO_DATA_PORT (IO_INDEX_PORT+1) |
35 | |
36 | #define UNLOCK_DATA 0x87 |
37 | #define LOCK_DATA 0xAA |
38 | #define DEVICE_REGISTER 0x07 |
39 | |
40 | #define DEFAULT_TIMEOUT 45 /* default timeout in seconds */ |
41 | |
42 | static int timeout = DEFAULT_TIMEOUT; |
43 | static int timeoutW; /* timeout in watchdog counter units */ |
44 | static unsigned long timer_alive; |
45 | static int testmode; |
46 | static char expect_close; |
47 | static DEFINE_SPINLOCK(spinlock); |
48 | |
49 | module_param(timeout, int, 0); |
50 | MODULE_PARM_DESC(timeout, |
51 | "Watchdog timeout in seconds (15..7635), default=" |
52 | __MODULE_STRING(DEFAULT_TIMEOUT) ")" ); |
53 | module_param(testmode, int, 0); |
54 | MODULE_PARM_DESC(testmode, "Watchdog testmode (1 = no reboot), default=0" ); |
55 | |
56 | static bool nowayout = WATCHDOG_NOWAYOUT; |
57 | module_param(nowayout, bool, 0); |
58 | MODULE_PARM_DESC(nowayout, |
59 | "Watchdog cannot be stopped once started (default=" |
60 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")" ); |
61 | |
62 | /* |
63 | * Start the watchdog |
64 | */ |
65 | |
66 | static int wdt_start(void) |
67 | { |
68 | unsigned long flags; |
69 | |
70 | spin_lock_irqsave(&spinlock, flags); |
71 | |
72 | /* Unlock the SuperIO chip */ |
73 | outb_p(UNLOCK_DATA, IO_INDEX_PORT); |
74 | outb_p(UNLOCK_DATA, IO_INDEX_PORT); |
75 | |
76 | /* |
77 | * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4. |
78 | * F2 has the timeout in watchdog counter units. |
79 | * F3 is set to enable watchdog LED blink at timeout. |
80 | * F4 is used to just clear the TIMEOUT'ed state (bit 0). |
81 | */ |
82 | outb_p(DEVICE_REGISTER, IO_INDEX_PORT); |
83 | outb_p(value: 0x08, IO_DATA_PORT); |
84 | outb_p(value: 0xF2, IO_INDEX_PORT); |
85 | outb_p(value: timeoutW, IO_DATA_PORT); |
86 | outb_p(value: 0xF3, IO_INDEX_PORT); |
87 | outb_p(value: 0x08, IO_DATA_PORT); |
88 | outb_p(value: 0xF4, IO_INDEX_PORT); |
89 | outb_p(value: 0x00, IO_DATA_PORT); |
90 | |
91 | /* Set device Aux2 active */ |
92 | outb_p(value: 0x30, IO_INDEX_PORT); |
93 | outb_p(value: 0x01, IO_DATA_PORT); |
94 | |
95 | /* |
96 | * Select device Aux1 (dev=7) to set GP16 as the watchdog output |
97 | * (in reg E6) and GP13 as the watchdog LED output (in reg E3). |
98 | * Map GP16 at pin 119. |
99 | * In test mode watch the bit 0 on F4 to indicate "triggered" or |
100 | * check watchdog LED on SBC. |
101 | */ |
102 | outb_p(DEVICE_REGISTER, IO_INDEX_PORT); |
103 | outb_p(value: 0x07, IO_DATA_PORT); |
104 | if (!testmode) { |
105 | unsigned pin_map; |
106 | |
107 | outb_p(value: 0xE6, IO_INDEX_PORT); |
108 | outb_p(value: 0x0A, IO_DATA_PORT); |
109 | outb_p(value: 0x2C, IO_INDEX_PORT); |
110 | pin_map = inb_p(IO_DATA_PORT); |
111 | pin_map |= 0x10; |
112 | pin_map &= ~(0x20); |
113 | outb_p(value: 0x2C, IO_INDEX_PORT); |
114 | outb_p(value: pin_map, IO_DATA_PORT); |
115 | } |
116 | outb_p(value: 0xE3, IO_INDEX_PORT); |
117 | outb_p(value: 0x08, IO_DATA_PORT); |
118 | |
119 | /* Set device Aux1 active */ |
120 | outb_p(value: 0x30, IO_INDEX_PORT); |
121 | outb_p(value: 0x01, IO_DATA_PORT); |
122 | |
123 | /* Lock the SuperIO chip */ |
124 | outb_p(LOCK_DATA, IO_INDEX_PORT); |
125 | |
126 | spin_unlock_irqrestore(lock: &spinlock, flags); |
127 | |
128 | pr_info("activated\n" ); |
129 | |
130 | return 0; |
131 | } |
132 | |
133 | /* |
134 | * Stop the watchdog |
135 | */ |
136 | |
137 | static int wdt_stop(void) |
138 | { |
139 | unsigned long flags; |
140 | |
141 | spin_lock_irqsave(&spinlock, flags); |
142 | |
143 | /* Unlock the SuperIO chip */ |
144 | outb_p(UNLOCK_DATA, IO_INDEX_PORT); |
145 | outb_p(UNLOCK_DATA, IO_INDEX_PORT); |
146 | |
147 | /* |
148 | * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4. |
149 | * F2 is reset to its default value (watchdog timer disabled). |
150 | * F3 is reset to its default state. |
151 | * F4 clears the TIMEOUT'ed state (bit 0) - back to default. |
152 | */ |
153 | outb_p(DEVICE_REGISTER, IO_INDEX_PORT); |
154 | outb_p(value: 0x08, IO_DATA_PORT); |
155 | outb_p(value: 0xF2, IO_INDEX_PORT); |
156 | outb_p(value: 0xFF, IO_DATA_PORT); |
157 | outb_p(value: 0xF3, IO_INDEX_PORT); |
158 | outb_p(value: 0x00, IO_DATA_PORT); |
159 | outb_p(value: 0xF4, IO_INDEX_PORT); |
160 | outb_p(value: 0x00, IO_DATA_PORT); |
161 | outb_p(value: 0xF2, IO_INDEX_PORT); |
162 | outb_p(value: 0x00, IO_DATA_PORT); |
163 | |
164 | /* |
165 | * Select device Aux1 (dev=7) to set GP16 (in reg E6) and |
166 | * Gp13 (in reg E3) as inputs. |
167 | */ |
168 | outb_p(DEVICE_REGISTER, IO_INDEX_PORT); |
169 | outb_p(value: 0x07, IO_DATA_PORT); |
170 | if (!testmode) { |
171 | outb_p(value: 0xE6, IO_INDEX_PORT); |
172 | outb_p(value: 0x01, IO_DATA_PORT); |
173 | } |
174 | outb_p(value: 0xE3, IO_INDEX_PORT); |
175 | outb_p(value: 0x01, IO_DATA_PORT); |
176 | |
177 | /* Lock the SuperIO chip */ |
178 | outb_p(LOCK_DATA, IO_INDEX_PORT); |
179 | |
180 | spin_unlock_irqrestore(lock: &spinlock, flags); |
181 | |
182 | pr_info("shutdown\n" ); |
183 | |
184 | return 0; |
185 | } |
186 | |
187 | /* |
188 | * Send a keepalive ping to the watchdog |
189 | * This is done by simply re-writing the timeout to reg. 0xF2 |
190 | */ |
191 | |
192 | static int wdt_keepalive(void) |
193 | { |
194 | unsigned long flags; |
195 | |
196 | spin_lock_irqsave(&spinlock, flags); |
197 | |
198 | /* Unlock the SuperIO chip */ |
199 | outb_p(UNLOCK_DATA, IO_INDEX_PORT); |
200 | outb_p(UNLOCK_DATA, IO_INDEX_PORT); |
201 | |
202 | /* Select device Aux2 (device=8) to kick watchdog reg F2 */ |
203 | outb_p(DEVICE_REGISTER, IO_INDEX_PORT); |
204 | outb_p(value: 0x08, IO_DATA_PORT); |
205 | outb_p(value: 0xF2, IO_INDEX_PORT); |
206 | outb_p(value: timeoutW, IO_DATA_PORT); |
207 | |
208 | /* Lock the SuperIO chip */ |
209 | outb_p(LOCK_DATA, IO_INDEX_PORT); |
210 | |
211 | spin_unlock_irqrestore(lock: &spinlock, flags); |
212 | |
213 | return 0; |
214 | } |
215 | |
216 | /* |
217 | * Set the watchdog timeout value |
218 | */ |
219 | |
220 | static int wdt_set_timeout(int t) |
221 | { |
222 | unsigned int tmrval; |
223 | |
224 | /* |
225 | * Convert seconds to watchdog counter time units, rounding up. |
226 | * On PCM-5335 watchdog units are 30 seconds/step with 15 sec startup |
227 | * value. This information is supplied in the PCM-5335 manual and was |
228 | * checked by me on a real board. This is a bit strange because W83977f |
229 | * datasheet says counter unit is in minutes! |
230 | */ |
231 | if (t < 15) |
232 | return -EINVAL; |
233 | |
234 | tmrval = ((t + 15) + 29) / 30; |
235 | |
236 | if (tmrval > 255) |
237 | return -EINVAL; |
238 | |
239 | /* |
240 | * timeout is the timeout in seconds, |
241 | * timeoutW is the timeout in watchdog counter units. |
242 | */ |
243 | timeoutW = tmrval; |
244 | timeout = (timeoutW * 30) - 15; |
245 | return 0; |
246 | } |
247 | |
248 | /* |
249 | * Get the watchdog status |
250 | */ |
251 | |
252 | static int wdt_get_status(int *status) |
253 | { |
254 | int new_status; |
255 | unsigned long flags; |
256 | |
257 | spin_lock_irqsave(&spinlock, flags); |
258 | |
259 | /* Unlock the SuperIO chip */ |
260 | outb_p(UNLOCK_DATA, IO_INDEX_PORT); |
261 | outb_p(UNLOCK_DATA, IO_INDEX_PORT); |
262 | |
263 | /* Select device Aux2 (device=8) to read watchdog reg F4 */ |
264 | outb_p(DEVICE_REGISTER, IO_INDEX_PORT); |
265 | outb_p(value: 0x08, IO_DATA_PORT); |
266 | outb_p(value: 0xF4, IO_INDEX_PORT); |
267 | new_status = inb_p(IO_DATA_PORT); |
268 | |
269 | /* Lock the SuperIO chip */ |
270 | outb_p(LOCK_DATA, IO_INDEX_PORT); |
271 | |
272 | spin_unlock_irqrestore(lock: &spinlock, flags); |
273 | |
274 | *status = 0; |
275 | if (new_status & 1) |
276 | *status |= WDIOF_CARDRESET; |
277 | |
278 | return 0; |
279 | } |
280 | |
281 | |
282 | /* |
283 | * /dev/watchdog handling |
284 | */ |
285 | |
286 | static int wdt_open(struct inode *inode, struct file *file) |
287 | { |
288 | /* If the watchdog is alive we don't need to start it again */ |
289 | if (test_and_set_bit(nr: 0, addr: &timer_alive)) |
290 | return -EBUSY; |
291 | |
292 | if (nowayout) |
293 | __module_get(THIS_MODULE); |
294 | |
295 | wdt_start(); |
296 | return stream_open(inode, filp: file); |
297 | } |
298 | |
299 | static int wdt_release(struct inode *inode, struct file *file) |
300 | { |
301 | /* |
302 | * Shut off the timer. |
303 | * Lock it in if it's a module and we set nowayout |
304 | */ |
305 | if (expect_close == 42) { |
306 | wdt_stop(); |
307 | clear_bit(nr: 0, addr: &timer_alive); |
308 | } else { |
309 | wdt_keepalive(); |
310 | pr_crit("unexpected close, not stopping watchdog!\n" ); |
311 | } |
312 | expect_close = 0; |
313 | return 0; |
314 | } |
315 | |
316 | /* |
317 | * wdt_write: |
318 | * @file: file handle to the watchdog |
319 | * @buf: buffer to write (unused as data does not matter here |
320 | * @count: count of bytes |
321 | * @ppos: pointer to the position to write. No seeks allowed |
322 | * |
323 | * A write to a watchdog device is defined as a keepalive signal. Any |
324 | * write of data will do, as we don't define content meaning. |
325 | */ |
326 | |
327 | static ssize_t wdt_write(struct file *file, const char __user *buf, |
328 | size_t count, loff_t *ppos) |
329 | { |
330 | /* See if we got the magic character 'V' and reload the timer */ |
331 | if (count) { |
332 | if (!nowayout) { |
333 | size_t ofs; |
334 | |
335 | /* note: just in case someone wrote the |
336 | magic character long ago */ |
337 | expect_close = 0; |
338 | |
339 | /* scan to see whether or not we got the |
340 | magic character */ |
341 | for (ofs = 0; ofs != count; ofs++) { |
342 | char c; |
343 | if (get_user(c, buf + ofs)) |
344 | return -EFAULT; |
345 | if (c == 'V') |
346 | expect_close = 42; |
347 | } |
348 | } |
349 | |
350 | /* someone wrote to us, we should restart timer */ |
351 | wdt_keepalive(); |
352 | } |
353 | return count; |
354 | } |
355 | |
356 | /* |
357 | * wdt_ioctl: |
358 | * @inode: inode of the device |
359 | * @file: file handle to the device |
360 | * @cmd: watchdog command |
361 | * @arg: argument pointer |
362 | * |
363 | * The watchdog API defines a common set of functions for all watchdogs |
364 | * according to their available features. |
365 | */ |
366 | |
367 | static const struct watchdog_info ident = { |
368 | .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, |
369 | .firmware_version = 1, |
370 | .identity = WATCHDOG_NAME, |
371 | }; |
372 | |
373 | static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
374 | { |
375 | int status; |
376 | int new_options, retval = -EINVAL; |
377 | int new_timeout; |
378 | union { |
379 | struct watchdog_info __user *ident; |
380 | int __user *i; |
381 | } uarg; |
382 | |
383 | uarg.i = (int __user *)arg; |
384 | |
385 | switch (cmd) { |
386 | case WDIOC_GETSUPPORT: |
387 | return copy_to_user(to: uarg.ident, from: &ident, |
388 | n: sizeof(ident)) ? -EFAULT : 0; |
389 | |
390 | case WDIOC_GETSTATUS: |
391 | wdt_get_status(status: &status); |
392 | return put_user(status, uarg.i); |
393 | |
394 | case WDIOC_GETBOOTSTATUS: |
395 | return put_user(0, uarg.i); |
396 | |
397 | case WDIOC_SETOPTIONS: |
398 | if (get_user(new_options, uarg.i)) |
399 | return -EFAULT; |
400 | |
401 | if (new_options & WDIOS_DISABLECARD) { |
402 | wdt_stop(); |
403 | retval = 0; |
404 | } |
405 | |
406 | if (new_options & WDIOS_ENABLECARD) { |
407 | wdt_start(); |
408 | retval = 0; |
409 | } |
410 | |
411 | return retval; |
412 | |
413 | case WDIOC_KEEPALIVE: |
414 | wdt_keepalive(); |
415 | return 0; |
416 | |
417 | case WDIOC_SETTIMEOUT: |
418 | if (get_user(new_timeout, uarg.i)) |
419 | return -EFAULT; |
420 | |
421 | if (wdt_set_timeout(t: new_timeout)) |
422 | return -EINVAL; |
423 | |
424 | wdt_keepalive(); |
425 | fallthrough; |
426 | |
427 | case WDIOC_GETTIMEOUT: |
428 | return put_user(timeout, uarg.i); |
429 | |
430 | default: |
431 | return -ENOTTY; |
432 | |
433 | } |
434 | } |
435 | |
436 | static int wdt_notify_sys(struct notifier_block *this, unsigned long code, |
437 | void *unused) |
438 | { |
439 | if (code == SYS_DOWN || code == SYS_HALT) |
440 | wdt_stop(); |
441 | return NOTIFY_DONE; |
442 | } |
443 | |
444 | static const struct file_operations wdt_fops = { |
445 | .owner = THIS_MODULE, |
446 | .llseek = no_llseek, |
447 | .write = wdt_write, |
448 | .unlocked_ioctl = wdt_ioctl, |
449 | .compat_ioctl = compat_ptr_ioctl, |
450 | .open = wdt_open, |
451 | .release = wdt_release, |
452 | }; |
453 | |
454 | static struct miscdevice wdt_miscdev = { |
455 | .minor = WATCHDOG_MINOR, |
456 | .name = "watchdog" , |
457 | .fops = &wdt_fops, |
458 | }; |
459 | |
460 | static struct notifier_block wdt_notifier = { |
461 | .notifier_call = wdt_notify_sys, |
462 | }; |
463 | |
464 | static int __init w83977f_wdt_init(void) |
465 | { |
466 | int rc; |
467 | |
468 | pr_info("driver v%s\n" , WATCHDOG_VERSION); |
469 | |
470 | /* |
471 | * Check that the timeout value is within it's range; |
472 | * if not reset to the default |
473 | */ |
474 | if (wdt_set_timeout(t: timeout)) { |
475 | wdt_set_timeout(DEFAULT_TIMEOUT); |
476 | pr_info("timeout value must be 15 <= timeout <= 7635, using %d\n" , |
477 | DEFAULT_TIMEOUT); |
478 | } |
479 | |
480 | if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME)) { |
481 | pr_err("I/O address 0x%04x already in use\n" , IO_INDEX_PORT); |
482 | rc = -EIO; |
483 | goto err_out; |
484 | } |
485 | |
486 | rc = register_reboot_notifier(&wdt_notifier); |
487 | if (rc) { |
488 | pr_err("cannot register reboot notifier (err=%d)\n" , rc); |
489 | goto err_out_region; |
490 | } |
491 | |
492 | rc = misc_register(misc: &wdt_miscdev); |
493 | if (rc) { |
494 | pr_err("cannot register miscdev on minor=%d (err=%d)\n" , |
495 | wdt_miscdev.minor, rc); |
496 | goto err_out_reboot; |
497 | } |
498 | |
499 | pr_info("initialized. timeout=%d sec (nowayout=%d testmode=%d)\n" , |
500 | timeout, nowayout, testmode); |
501 | |
502 | return 0; |
503 | |
504 | err_out_reboot: |
505 | unregister_reboot_notifier(&wdt_notifier); |
506 | err_out_region: |
507 | release_region(IO_INDEX_PORT, 2); |
508 | err_out: |
509 | return rc; |
510 | } |
511 | |
512 | static void __exit w83977f_wdt_exit(void) |
513 | { |
514 | wdt_stop(); |
515 | misc_deregister(misc: &wdt_miscdev); |
516 | unregister_reboot_notifier(&wdt_notifier); |
517 | release_region(IO_INDEX_PORT, 2); |
518 | } |
519 | |
520 | module_init(w83977f_wdt_init); |
521 | module_exit(w83977f_wdt_exit); |
522 | |
523 | MODULE_AUTHOR("Jose Goncalves <jose.goncalves@inov.pt>" ); |
524 | MODULE_DESCRIPTION("Driver for watchdog timer in W83977F I/O chip" ); |
525 | MODULE_LICENSE("GPL" ); |
526 | |