Commit | Line | Data |
---|---|---|
2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* |
3 | * W83877F Computer Watchdog Timer driver | |
4 | * | |
5 | * Based on acquirewdt.c by Alan Cox, | |
6 | * and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net> | |
7 | * | |
1da177e4 LT |
8 | * The authors do NOT admit liability nor provide warranty for |
9 | * any of this software. This material is provided "AS-IS" in | |
10 | * the hope that it may be useful for others. | |
11 | * | |
12 | * (c) Copyright 2001 Scott Jennings <linuxdrivers@oro.net> | |
13 | * | |
14 | * 4/19 - 2001 [Initial revision] | |
15 | * 9/27 - 2001 Added spinlocking | |
16 | * 4/12 - 2002 [rob@osinvestor.com] Eliminate extra comments | |
17 | * Eliminate fop_read | |
18 | * Eliminate extra spin_unlock | |
19 | * Added KERN_* tags to printks | |
20 | * add CONFIG_WATCHDOG_NOWAYOUT support | |
21 | * fix possible wdt_is_open race | |
c1cfd1a2 AC |
22 | * changed watchdog_info to correctly reflect what |
23 | * the driver offers | |
24 | * added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS, | |
25 | * WDIOC_SETTIMEOUT, | |
1da177e4 LT |
26 | * WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls |
27 | * 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces | |
28 | * added extra printk's for startup problems | |
29 | * use module_param | |
c1cfd1a2 AC |
30 | * made timeout (the emulated heartbeat) a |
31 | * module_param | |
1da177e4 LT |
32 | * made the keepalive ping an internal subroutine |
33 | * | |
34 | * This WDT driver is different from most other Linux WDT | |
35 | * drivers in that the driver will ping the watchdog by itself, | |
36 | * because this particular WDT has a very short timeout (1.6 | |
37 | * seconds) and it would be insane to count on any userspace | |
38 | * daemon always getting scheduled within that time frame. | |
39 | */ | |
40 | ||
27c766aa JP |
41 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
42 | ||
1da177e4 LT |
43 | #include <linux/module.h> |
44 | #include <linux/moduleparam.h> | |
45 | #include <linux/types.h> | |
46 | #include <linux/timer.h> | |
47 | #include <linux/jiffies.h> | |
48 | #include <linux/miscdevice.h> | |
49 | #include <linux/watchdog.h> | |
50 | #include <linux/fs.h> | |
51 | #include <linux/ioport.h> | |
52 | #include <linux/notifier.h> | |
53 | #include <linux/reboot.h> | |
54 | #include <linux/init.h> | |
c1cfd1a2 AC |
55 | #include <linux/io.h> |
56 | #include <linux/uaccess.h> | |
1da177e4 LT |
57 | |
58 | #define OUR_NAME "w83877f_wdt" | |
1da177e4 LT |
59 | |
60 | #define ENABLE_W83877F_PORT 0x3F0 | |
61 | #define ENABLE_W83877F 0x87 | |
62 | #define DISABLE_W83877F 0xAA | |
63 | #define WDT_PING 0x443 | |
64 | #define WDT_REGISTER 0x14 | |
65 | #define WDT_ENABLE 0x9C | |
66 | #define WDT_DISABLE 0x8C | |
67 | ||
68 | /* | |
69 | * The W83877F seems to be fixed at 1.6s timeout (at least on the | |
70 | * EMACS PC-104 board I'm using). If we reset the watchdog every | |
71 | * ~250ms we should be safe. */ | |
72 | ||
73 | #define WDT_INTERVAL (HZ/4+1) | |
74 | ||
75 | /* | |
76 | * We must not require too good response from the userspace daemon. | |
77 | * Here we require the userspace daemon to send us a heartbeat | |
78 | * char to /dev/watchdog every 30 seconds. | |
79 | */ | |
80 | ||
81 | #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ | |
c1cfd1a2 AC |
82 | /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ |
83 | static int timeout = WATCHDOG_TIMEOUT; | |
1da177e4 | 84 | module_param(timeout, int, 0); |
c1cfd1a2 AC |
85 | MODULE_PARM_DESC(timeout, |
86 | "Watchdog timeout in seconds. (1<=timeout<=3600, default=" | |
87 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
1da177e4 LT |
88 | |
89 | ||
86a1e189 WVS |
90 | static bool nowayout = WATCHDOG_NOWAYOUT; |
91 | module_param(nowayout, bool, 0); | |
c1cfd1a2 AC |
92 | MODULE_PARM_DESC(nowayout, |
93 | "Watchdog cannot be stopped once started (default=" | |
94 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
1da177e4 | 95 | |
24ed960a | 96 | static void wdt_timer_ping(struct timer_list *); |
1d27e3e2 | 97 | static DEFINE_TIMER(timer, wdt_timer_ping); |
1da177e4 LT |
98 | static unsigned long next_heartbeat; |
99 | static unsigned long wdt_is_open; | |
100 | static char wdt_expect_close; | |
c7dfd0cc | 101 | static DEFINE_SPINLOCK(wdt_spinlock); |
1da177e4 LT |
102 | |
103 | /* | |
104 | * Whack the dog | |
105 | */ | |
106 | ||
24ed960a | 107 | static void wdt_timer_ping(struct timer_list *unused) |
1da177e4 LT |
108 | { |
109 | /* If we got a heartbeat pulse within the WDT_US_INTERVAL | |
110 | * we agree to ping the WDT | |
111 | */ | |
c1cfd1a2 | 112 | if (time_before(jiffies, next_heartbeat)) { |
1da177e4 LT |
113 | /* Ping the WDT */ |
114 | spin_lock(&wdt_spinlock); | |
115 | ||
116 | /* Ping the WDT by reading from WDT_PING */ | |
117 | inb_p(WDT_PING); | |
118 | ||
119 | /* Re-set the timer interval */ | |
82eb7c50 | 120 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
1da177e4 LT |
121 | |
122 | spin_unlock(&wdt_spinlock); | |
123 | ||
c1cfd1a2 | 124 | } else |
27c766aa | 125 | pr_warn("Heartbeat lost! Will not ping the watchdog\n"); |
1da177e4 LT |
126 | } |
127 | ||
128 | /* | |
129 | * Utility routines | |
130 | */ | |
131 | ||
132 | static void wdt_change(int writeval) | |
133 | { | |
134 | unsigned long flags; | |
135 | spin_lock_irqsave(&wdt_spinlock, flags); | |
136 | ||
137 | /* buy some time */ | |
138 | inb_p(WDT_PING); | |
139 | ||
140 | /* make W83877F available */ | |
141 | outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); | |
142 | outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); | |
143 | ||
144 | /* enable watchdog */ | |
145 | outb_p(WDT_REGISTER, ENABLE_W83877F_PORT); | |
146 | outb_p(writeval, ENABLE_W83877F_PORT+1); | |
147 | ||
148 | /* lock the W8387FF away */ | |
149 | outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT); | |
150 | ||
151 | spin_unlock_irqrestore(&wdt_spinlock, flags); | |
152 | } | |
153 | ||
154 | static void wdt_startup(void) | |
155 | { | |
156 | next_heartbeat = jiffies + (timeout * HZ); | |
157 | ||
158 | /* Start the timer */ | |
82eb7c50 | 159 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
1da177e4 LT |
160 | |
161 | wdt_change(WDT_ENABLE); | |
162 | ||
27c766aa | 163 | pr_info("Watchdog timer is now enabled\n"); |
1da177e4 LT |
164 | } |
165 | ||
166 | static void wdt_turnoff(void) | |
167 | { | |
168 | /* Stop the timer */ | |
d0212f09 | 169 | del_timer_sync(&timer); |
1da177e4 LT |
170 | |
171 | wdt_change(WDT_DISABLE); | |
172 | ||
27c766aa | 173 | pr_info("Watchdog timer is now disabled...\n"); |
1da177e4 LT |
174 | } |
175 | ||
176 | static void wdt_keepalive(void) | |
177 | { | |
178 | /* user land ping */ | |
179 | next_heartbeat = jiffies + (timeout * HZ); | |
180 | } | |
181 | ||
182 | /* | |
183 | * /dev/watchdog handling | |
184 | */ | |
185 | ||
c1cfd1a2 AC |
186 | static ssize_t fop_write(struct file *file, const char __user *buf, |
187 | size_t count, loff_t *ppos) | |
1da177e4 LT |
188 | { |
189 | /* See if we got the magic character 'V' and reload the timer */ | |
c1cfd1a2 AC |
190 | if (count) { |
191 | if (!nowayout) { | |
1da177e4 LT |
192 | size_t ofs; |
193 | ||
c1cfd1a2 AC |
194 | /* note: just in case someone wrote the magic |
195 | character five months ago... */ | |
1da177e4 LT |
196 | wdt_expect_close = 0; |
197 | ||
c1cfd1a2 AC |
198 | /* scan to see whether or not we got the |
199 | magic character */ | |
200 | for (ofs = 0; ofs != count; ofs++) { | |
1da177e4 LT |
201 | char c; |
202 | if (get_user(c, buf + ofs)) | |
203 | return -EFAULT; | |
204 | if (c == 'V') | |
205 | wdt_expect_close = 42; | |
206 | } | |
207 | } | |
208 | ||
209 | /* someone wrote to us, we should restart timer */ | |
210 | wdt_keepalive(); | |
211 | } | |
212 | return count; | |
213 | } | |
214 | ||
c1cfd1a2 | 215 | static int fop_open(struct inode *inode, struct file *file) |
1da177e4 LT |
216 | { |
217 | /* Just in case we're already talking to someone... */ | |
c1cfd1a2 | 218 | if (test_and_set_bit(0, &wdt_is_open)) |
1da177e4 LT |
219 | return -EBUSY; |
220 | ||
221 | /* Good, fire up the show */ | |
222 | wdt_startup(); | |
c5bf68fe | 223 | return stream_open(inode, file); |
1da177e4 LT |
224 | } |
225 | ||
c1cfd1a2 | 226 | static int fop_close(struct inode *inode, struct file *file) |
1da177e4 | 227 | { |
c1cfd1a2 | 228 | if (wdt_expect_close == 42) |
1da177e4 LT |
229 | wdt_turnoff(); |
230 | else { | |
231 | del_timer(&timer); | |
27c766aa | 232 | pr_crit("device file closed unexpectedly. Will not stop the WDT!\n"); |
1da177e4 LT |
233 | } |
234 | clear_bit(0, &wdt_is_open); | |
235 | wdt_expect_close = 0; | |
236 | return 0; | |
237 | } | |
238 | ||
c1cfd1a2 | 239 | static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
1da177e4 LT |
240 | { |
241 | void __user *argp = (void __user *)arg; | |
242 | int __user *p = argp; | |
c1cfd1a2 AC |
243 | static const struct watchdog_info ident = { |
244 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | |
245 | | WDIOF_MAGICCLOSE, | |
1da177e4 LT |
246 | .firmware_version = 1, |
247 | .identity = "W83877F", | |
248 | }; | |
249 | ||
c1cfd1a2 | 250 | switch (cmd) { |
c1cfd1a2 AC |
251 | case WDIOC_GETSUPPORT: |
252 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; | |
253 | case WDIOC_GETSTATUS: | |
254 | case WDIOC_GETBOOTSTATUS: | |
255 | return put_user(0, p); | |
c1cfd1a2 | 256 | case WDIOC_SETOPTIONS: |
1da177e4 | 257 | { |
c1cfd1a2 | 258 | int new_options, retval = -EINVAL; |
1da177e4 | 259 | |
c1cfd1a2 AC |
260 | if (get_user(new_options, p)) |
261 | return -EFAULT; | |
1da177e4 | 262 | |
c1cfd1a2 AC |
263 | if (new_options & WDIOS_DISABLECARD) { |
264 | wdt_turnoff(); | |
265 | retval = 0; | |
1da177e4 | 266 | } |
1da177e4 | 267 | |
c1cfd1a2 AC |
268 | if (new_options & WDIOS_ENABLECARD) { |
269 | wdt_startup(); | |
270 | retval = 0; | |
271 | } | |
1da177e4 | 272 | |
c1cfd1a2 AC |
273 | return retval; |
274 | } | |
0c06090c WVS |
275 | case WDIOC_KEEPALIVE: |
276 | wdt_keepalive(); | |
277 | return 0; | |
c1cfd1a2 AC |
278 | case WDIOC_SETTIMEOUT: |
279 | { | |
280 | int new_timeout; | |
1da177e4 | 281 | |
c1cfd1a2 AC |
282 | if (get_user(new_timeout, p)) |
283 | return -EFAULT; | |
284 | ||
285 | /* arbitrary upper limit */ | |
286 | if (new_timeout < 1 || new_timeout > 3600) | |
287 | return -EINVAL; | |
288 | ||
289 | timeout = new_timeout; | |
290 | wdt_keepalive(); | |
c1cfd1a2 | 291 | } |
bd490f82 | 292 | fallthrough; |
c1cfd1a2 AC |
293 | case WDIOC_GETTIMEOUT: |
294 | return put_user(timeout, p); | |
0c06090c WVS |
295 | default: |
296 | return -ENOTTY; | |
1da177e4 LT |
297 | } |
298 | } | |
299 | ||
62322d25 | 300 | static const struct file_operations wdt_fops = { |
1da177e4 LT |
301 | .owner = THIS_MODULE, |
302 | .llseek = no_llseek, | |
303 | .write = fop_write, | |
304 | .open = fop_open, | |
305 | .release = fop_close, | |
c1cfd1a2 | 306 | .unlocked_ioctl = fop_ioctl, |
b6dfb247 | 307 | .compat_ioctl = compat_ptr_ioctl, |
1da177e4 LT |
308 | }; |
309 | ||
310 | static struct miscdevice wdt_miscdev = { | |
311 | .minor = WATCHDOG_MINOR, | |
312 | .name = "watchdog", | |
313 | .fops = &wdt_fops, | |
314 | }; | |
315 | ||
316 | /* | |
317 | * Notifier for system down | |
318 | */ | |
319 | ||
320 | static int wdt_notify_sys(struct notifier_block *this, unsigned long code, | |
321 | void *unused) | |
322 | { | |
c1cfd1a2 | 323 | if (code == SYS_DOWN || code == SYS_HALT) |
1da177e4 LT |
324 | wdt_turnoff(); |
325 | return NOTIFY_DONE; | |
326 | } | |
327 | ||
328 | /* | |
329 | * The WDT needs to learn about soft shutdowns in order to | |
330 | * turn the timebomb registers off. | |
331 | */ | |
332 | ||
c1cfd1a2 | 333 | static struct notifier_block wdt_notifier = { |
1da177e4 LT |
334 | .notifier_call = wdt_notify_sys, |
335 | }; | |
336 | ||
337 | static void __exit w83877f_wdt_unload(void) | |
338 | { | |
339 | wdt_turnoff(); | |
340 | ||
341 | /* Deregister */ | |
342 | misc_deregister(&wdt_miscdev); | |
343 | ||
344 | unregister_reboot_notifier(&wdt_notifier); | |
c1cfd1a2 AC |
345 | release_region(WDT_PING, 1); |
346 | release_region(ENABLE_W83877F_PORT, 2); | |
1da177e4 LT |
347 | } |
348 | ||
349 | static int __init w83877f_wdt_init(void) | |
350 | { | |
351 | int rc = -EBUSY; | |
352 | ||
c1cfd1a2 | 353 | if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */ |
1da177e4 | 354 | timeout = WATCHDOG_TIMEOUT; |
27c766aa JP |
355 | pr_info("timeout value must be 1 <= x <= 3600, using %d\n", |
356 | timeout); | |
1da177e4 LT |
357 | } |
358 | ||
c1cfd1a2 | 359 | if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) { |
27c766aa JP |
360 | pr_err("I/O address 0x%04x already in use\n", |
361 | ENABLE_W83877F_PORT); | |
1da177e4 LT |
362 | rc = -EIO; |
363 | goto err_out; | |
364 | } | |
365 | ||
c1cfd1a2 | 366 | if (!request_region(WDT_PING, 1, "W8387FF WDT")) { |
27c766aa | 367 | pr_err("I/O address 0x%04x already in use\n", WDT_PING); |
1da177e4 LT |
368 | rc = -EIO; |
369 | goto err_out_region1; | |
370 | } | |
371 | ||
c6cb13ae | 372 | rc = register_reboot_notifier(&wdt_notifier); |
c1cfd1a2 | 373 | if (rc) { |
27c766aa | 374 | pr_err("cannot register reboot notifier (err=%d)\n", rc); |
1da177e4 LT |
375 | goto err_out_region2; |
376 | } | |
377 | ||
c6cb13ae | 378 | rc = misc_register(&wdt_miscdev); |
c1cfd1a2 | 379 | if (rc) { |
27c766aa JP |
380 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
381 | wdt_miscdev.minor, rc); | |
c6cb13ae | 382 | goto err_out_reboot; |
1da177e4 LT |
383 | } |
384 | ||
27c766aa | 385 | pr_info("WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n", |
1da177e4 LT |
386 | timeout, nowayout); |
387 | ||
388 | return 0; | |
389 | ||
c6cb13ae WVS |
390 | err_out_reboot: |
391 | unregister_reboot_notifier(&wdt_notifier); | |
1da177e4 | 392 | err_out_region2: |
c1cfd1a2 | 393 | release_region(WDT_PING, 1); |
1da177e4 | 394 | err_out_region1: |
c1cfd1a2 | 395 | release_region(ENABLE_W83877F_PORT, 2); |
1da177e4 LT |
396 | err_out: |
397 | return rc; | |
398 | } | |
399 | ||
400 | module_init(w83877f_wdt_init); | |
401 | module_exit(w83877f_wdt_unload); | |
402 | ||
403 | MODULE_AUTHOR("Scott and Bill Jennings"); | |
404 | MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip"); | |
405 | MODULE_LICENSE("GPL"); |