Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * 60xx Single Board Computer Watchdog Timer driver for Linux 2.2.x | |
3 | * | |
143a2e54 | 4 | * Based on acquirewdt.c by Alan Cox. |
1da177e4 LT |
5 | * |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | * | |
11 | * The author does NOT admit liability nor provide warranty for | |
12 | * any of this software. This material is provided "AS-IS" in | |
13 | * the hope that it may be useful for others. | |
14 | * | |
15 | * (c) Copyright 2000 Jakob Oestergaard <jakob@unthought.net> | |
16 | * | |
17 | * 12/4 - 2000 [Initial revision] | |
18 | * 25/4 - 2000 Added /dev/watchdog support | |
1780de41 AC |
19 | * 09/5 - 2001 [smj@oro.net] fixed fop_write to "return 1" |
20 | * on success | |
1da177e4 LT |
21 | * 12/4 - 2002 [rob@osinvestor.com] eliminate fop_read |
22 | * fix possible wdt_is_open race | |
23 | * add CONFIG_WATCHDOG_NOWAYOUT support | |
24 | * remove lock_kernel/unlock_kernel pairs | |
25 | * added KERN_* to printk's | |
26 | * got rid of extraneous comments | |
1780de41 AC |
27 | * changed watchdog_info to correctly reflect what |
28 | * the driver offers | |
29 | * added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS, | |
30 | * WDIOC_SETTIMEOUT, WDIOC_GETTIMEOUT, and | |
31 | * WDIOC_SETOPTIONS ioctls | |
1da177e4 LT |
32 | * 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces |
33 | * use module_param | |
1780de41 AC |
34 | * made timeout (the emulated heartbeat) a |
35 | * module_param | |
1da177e4 LT |
36 | * made the keepalive ping an internal subroutine |
37 | * made wdt_stop and wdt_start module params | |
38 | * added extra printk's for startup problems | |
39 | * added MODULE_AUTHOR and MODULE_DESCRIPTION info | |
40 | * | |
41 | * | |
42 | * This WDT driver is different from the other Linux WDT | |
43 | * drivers in the following ways: | |
44 | * *) The driver will ping the watchdog by itself, because this | |
45 | * particular WDT has a very short timeout (one second) and it | |
46 | * would be insane to count on any userspace daemon always | |
47 | * getting scheduled within that time frame. | |
48 | * | |
49 | */ | |
50 | ||
27c766aa JP |
51 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
52 | ||
1da177e4 LT |
53 | #include <linux/module.h> |
54 | #include <linux/moduleparam.h> | |
55 | #include <linux/types.h> | |
56 | #include <linux/timer.h> | |
57 | #include <linux/jiffies.h> | |
58 | #include <linux/miscdevice.h> | |
59 | #include <linux/watchdog.h> | |
60 | #include <linux/fs.h> | |
61 | #include <linux/ioport.h> | |
62 | #include <linux/notifier.h> | |
63 | #include <linux/reboot.h> | |
64 | #include <linux/init.h> | |
1780de41 AC |
65 | #include <linux/io.h> |
66 | #include <linux/uaccess.h> | |
1da177e4 | 67 | |
1da177e4 LT |
68 | |
69 | #define OUR_NAME "sbc60xxwdt" | |
70 | #define PFX OUR_NAME ": " | |
71 | ||
72 | /* | |
73 | * You must set these - The driver cannot probe for the settings | |
74 | */ | |
75 | ||
76 | static int wdt_stop = 0x45; | |
77 | module_param(wdt_stop, int, 0); | |
78 | MODULE_PARM_DESC(wdt_stop, "SBC60xx WDT 'stop' io port (default 0x45)"); | |
79 | ||
80 | static int wdt_start = 0x443; | |
81 | module_param(wdt_start, int, 0); | |
82 | MODULE_PARM_DESC(wdt_start, "SBC60xx WDT 'start' io port (default 0x443)"); | |
83 | ||
84 | /* | |
85 | * The 60xx board can use watchdog timeout values from one second | |
86 | * to several minutes. The default is one second, so if we reset | |
87 | * the watchdog every ~250ms we should be safe. | |
88 | */ | |
89 | ||
90 | #define WDT_INTERVAL (HZ/4+1) | |
91 | ||
92 | /* | |
93 | * We must not require too good response from the userspace daemon. | |
94 | * Here we require the userspace daemon to send us a heartbeat | |
95 | * char to /dev/watchdog every 30 seconds. | |
96 | * If the daemon pulses us every 25 seconds, we can still afford | |
97 | * a 5 second scheduling delay on the (high priority) daemon. That | |
98 | * should be sufficient for a box under any load. | |
99 | */ | |
100 | ||
101 | #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ | |
1780de41 AC |
102 | static int timeout = WATCHDOG_TIMEOUT; /* in seconds, multiplied by HZ to |
103 | get seconds to wait for a ping */ | |
1da177e4 | 104 | module_param(timeout, int, 0); |
1780de41 AC |
105 | MODULE_PARM_DESC(timeout, |
106 | "Watchdog timeout in seconds. (1<=timeout<=3600, default=" | |
107 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
1da177e4 | 108 | |
86a1e189 WVS |
109 | static bool nowayout = WATCHDOG_NOWAYOUT; |
110 | module_param(nowayout, bool, 0); | |
1780de41 AC |
111 | MODULE_PARM_DESC(nowayout, |
112 | "Watchdog cannot be stopped once started (default=" | |
113 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
1da177e4 LT |
114 | |
115 | static void wdt_timer_ping(unsigned long); | |
82eb7c50 | 116 | static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0); |
1da177e4 LT |
117 | static unsigned long next_heartbeat; |
118 | static unsigned long wdt_is_open; | |
119 | static char wdt_expect_close; | |
120 | ||
121 | /* | |
122 | * Whack the dog | |
123 | */ | |
124 | ||
125 | static void wdt_timer_ping(unsigned long data) | |
126 | { | |
127 | /* If we got a heartbeat pulse within the WDT_US_INTERVAL | |
128 | * we agree to ping the WDT | |
129 | */ | |
1780de41 | 130 | if (time_before(jiffies, next_heartbeat)) { |
1da177e4 LT |
131 | /* Ping the WDT by reading from wdt_start */ |
132 | inb_p(wdt_start); | |
133 | /* Re-set the timer interval */ | |
82eb7c50 | 134 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
1780de41 | 135 | } else |
27c766aa | 136 | pr_warn("Heartbeat lost! Will not ping the watchdog\n"); |
1da177e4 LT |
137 | } |
138 | ||
139 | /* | |
140 | * Utility routines | |
141 | */ | |
142 | ||
143 | static void wdt_startup(void) | |
144 | { | |
145 | next_heartbeat = jiffies + (timeout * HZ); | |
146 | ||
147 | /* Start the timer */ | |
82eb7c50 | 148 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
27c766aa | 149 | pr_info("Watchdog timer is now enabled\n"); |
1da177e4 LT |
150 | } |
151 | ||
152 | static void wdt_turnoff(void) | |
153 | { | |
154 | /* Stop the timer */ | |
155 | del_timer(&timer); | |
156 | inb_p(wdt_stop); | |
27c766aa | 157 | pr_info("Watchdog timer is now disabled...\n"); |
1da177e4 LT |
158 | } |
159 | ||
160 | static void wdt_keepalive(void) | |
161 | { | |
162 | /* user land ping */ | |
163 | next_heartbeat = jiffies + (timeout * HZ); | |
164 | } | |
165 | ||
166 | /* | |
167 | * /dev/watchdog handling | |
168 | */ | |
169 | ||
1780de41 AC |
170 | static ssize_t fop_write(struct file *file, const char __user *buf, |
171 | size_t count, loff_t *ppos) | |
1da177e4 LT |
172 | { |
173 | /* See if we got the magic character 'V' and reload the timer */ | |
1780de41 AC |
174 | if (count) { |
175 | if (!nowayout) { | |
1da177e4 LT |
176 | size_t ofs; |
177 | ||
1780de41 AC |
178 | /* note: just in case someone wrote the |
179 | magic character five months ago... */ | |
1da177e4 LT |
180 | wdt_expect_close = 0; |
181 | ||
1780de41 AC |
182 | /* scan to see whether or not we got the |
183 | magic character */ | |
184 | for (ofs = 0; ofs != count; ofs++) { | |
1da177e4 | 185 | char c; |
7944d3a5 | 186 | if (get_user(c, buf + ofs)) |
1da177e4 | 187 | return -EFAULT; |
1780de41 | 188 | if (c == 'V') |
1da177e4 LT |
189 | wdt_expect_close = 42; |
190 | } | |
191 | } | |
192 | ||
1780de41 AC |
193 | /* Well, anyhow someone wrote to us, we should |
194 | return that favour */ | |
1da177e4 LT |
195 | wdt_keepalive(); |
196 | } | |
197 | return count; | |
198 | } | |
199 | ||
1780de41 | 200 | static int fop_open(struct inode *inode, struct file *file) |
1da177e4 | 201 | { |
1da177e4 | 202 | /* Just in case we're already talking to someone... */ |
1780de41 | 203 | if (test_and_set_bit(0, &wdt_is_open)) |
1da177e4 LT |
204 | return -EBUSY; |
205 | ||
206 | if (nowayout) | |
207 | __module_get(THIS_MODULE); | |
208 | ||
209 | /* Good, fire up the show */ | |
210 | wdt_startup(); | |
6abe78bf | 211 | return nonseekable_open(inode, file); |
1da177e4 LT |
212 | } |
213 | ||
1780de41 | 214 | static int fop_close(struct inode *inode, struct file *file) |
1da177e4 | 215 | { |
1780de41 | 216 | if (wdt_expect_close == 42) |
1da177e4 LT |
217 | wdt_turnoff(); |
218 | else { | |
219 | del_timer(&timer); | |
27c766aa | 220 | pr_crit("device file closed unexpectedly. Will not stop the WDT!\n"); |
1da177e4 LT |
221 | } |
222 | clear_bit(0, &wdt_is_open); | |
223 | wdt_expect_close = 0; | |
224 | return 0; | |
225 | } | |
226 | ||
1780de41 | 227 | static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
1da177e4 LT |
228 | { |
229 | void __user *argp = (void __user *)arg; | |
230 | int __user *p = argp; | |
1780de41 AC |
231 | static const struct watchdog_info ident = { |
232 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | | |
233 | WDIOF_MAGICCLOSE, | |
1da177e4 LT |
234 | .firmware_version = 1, |
235 | .identity = "SBC60xx", | |
236 | }; | |
237 | ||
1780de41 | 238 | switch (cmd) { |
1780de41 | 239 | case WDIOC_GETSUPPORT: |
7944d3a5 | 240 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; |
1780de41 AC |
241 | case WDIOC_GETSTATUS: |
242 | case WDIOC_GETBOOTSTATUS: | |
243 | return put_user(0, p); | |
1780de41 | 244 | case WDIOC_SETOPTIONS: |
1da177e4 | 245 | { |
1780de41 AC |
246 | int new_options, retval = -EINVAL; |
247 | if (get_user(new_options, p)) | |
248 | return -EFAULT; | |
249 | if (new_options & WDIOS_DISABLECARD) { | |
250 | wdt_turnoff(); | |
251 | retval = 0; | |
1da177e4 | 252 | } |
1780de41 AC |
253 | if (new_options & WDIOS_ENABLECARD) { |
254 | wdt_startup(); | |
255 | retval = 0; | |
1da177e4 | 256 | } |
1780de41 AC |
257 | return retval; |
258 | } | |
0c06090c WVS |
259 | case WDIOC_KEEPALIVE: |
260 | wdt_keepalive(); | |
261 | return 0; | |
1780de41 AC |
262 | case WDIOC_SETTIMEOUT: |
263 | { | |
264 | int new_timeout; | |
265 | if (get_user(new_timeout, p)) | |
266 | return -EFAULT; | |
267 | /* arbitrary upper limit */ | |
268 | if (new_timeout < 1 || new_timeout > 3600) | |
269 | return -EINVAL; | |
270 | ||
271 | timeout = new_timeout; | |
272 | wdt_keepalive(); | |
273 | /* Fall through */ | |
274 | } | |
275 | case WDIOC_GETTIMEOUT: | |
276 | return put_user(timeout, p); | |
0c06090c WVS |
277 | default: |
278 | return -ENOTTY; | |
1da177e4 LT |
279 | } |
280 | } | |
281 | ||
62322d25 | 282 | static const struct file_operations wdt_fops = { |
1da177e4 LT |
283 | .owner = THIS_MODULE, |
284 | .llseek = no_llseek, | |
285 | .write = fop_write, | |
286 | .open = fop_open, | |
287 | .release = fop_close, | |
1780de41 | 288 | .unlocked_ioctl = fop_ioctl, |
1da177e4 LT |
289 | }; |
290 | ||
291 | static struct miscdevice wdt_miscdev = { | |
292 | .minor = WATCHDOG_MINOR, | |
293 | .name = "watchdog", | |
294 | .fops = &wdt_fops, | |
295 | }; | |
296 | ||
297 | /* | |
298 | * Notifier for system down | |
299 | */ | |
300 | ||
301 | static int wdt_notify_sys(struct notifier_block *this, unsigned long code, | |
302 | void *unused) | |
303 | { | |
1780de41 | 304 | if (code == SYS_DOWN || code == SYS_HALT) |
1da177e4 LT |
305 | wdt_turnoff(); |
306 | return NOTIFY_DONE; | |
307 | } | |
308 | ||
309 | /* | |
310 | * The WDT needs to learn about soft shutdowns in order to | |
311 | * turn the timebomb registers off. | |
312 | */ | |
313 | ||
1780de41 | 314 | static struct notifier_block wdt_notifier = { |
1da177e4 LT |
315 | .notifier_call = wdt_notify_sys, |
316 | }; | |
317 | ||
318 | static void __exit sbc60xxwdt_unload(void) | |
319 | { | |
320 | wdt_turnoff(); | |
321 | ||
322 | /* Deregister */ | |
323 | misc_deregister(&wdt_miscdev); | |
324 | ||
325 | unregister_reboot_notifier(&wdt_notifier); | |
326 | if ((wdt_stop != 0x45) && (wdt_stop != wdt_start)) | |
1780de41 AC |
327 | release_region(wdt_stop, 1); |
328 | release_region(wdt_start, 1); | |
1da177e4 LT |
329 | } |
330 | ||
331 | static int __init sbc60xxwdt_init(void) | |
332 | { | |
333 | int rc = -EBUSY; | |
334 | ||
1780de41 | 335 | if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */ |
1da177e4 | 336 | timeout = WATCHDOG_TIMEOUT; |
27c766aa JP |
337 | pr_info("timeout value must be 1 <= x <= 3600, using %d\n", |
338 | timeout); | |
1780de41 | 339 | } |
1da177e4 | 340 | |
1780de41 | 341 | if (!request_region(wdt_start, 1, "SBC 60XX WDT")) { |
27c766aa | 342 | pr_err("I/O address 0x%04x already in use\n", wdt_start); |
1da177e4 LT |
343 | rc = -EIO; |
344 | goto err_out; | |
345 | } | |
346 | ||
347 | /* We cannot reserve 0x45 - the kernel already has! */ | |
1780de41 AC |
348 | if (wdt_stop != 0x45 && wdt_stop != wdt_start) { |
349 | if (!request_region(wdt_stop, 1, "SBC 60XX WDT")) { | |
27c766aa | 350 | pr_err("I/O address 0x%04x already in use\n", wdt_stop); |
1da177e4 LT |
351 | rc = -EIO; |
352 | goto err_out_region1; | |
353 | } | |
354 | } | |
355 | ||
c6cb13ae | 356 | rc = register_reboot_notifier(&wdt_notifier); |
1780de41 | 357 | if (rc) { |
27c766aa | 358 | pr_err("cannot register reboot notifier (err=%d)\n", rc); |
1da177e4 LT |
359 | goto err_out_region2; |
360 | } | |
361 | ||
c6cb13ae | 362 | rc = misc_register(&wdt_miscdev); |
1780de41 | 363 | if (rc) { |
27c766aa JP |
364 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
365 | wdt_miscdev.minor, rc); | |
c6cb13ae | 366 | goto err_out_reboot; |
1da177e4 | 367 | } |
27c766aa JP |
368 | pr_info("WDT driver for 60XX single board computer initialised. timeout=%d sec (nowayout=%d)\n", |
369 | timeout, nowayout); | |
1da177e4 LT |
370 | |
371 | return 0; | |
372 | ||
c6cb13ae WVS |
373 | err_out_reboot: |
374 | unregister_reboot_notifier(&wdt_notifier); | |
1da177e4 | 375 | err_out_region2: |
1780de41 AC |
376 | if (wdt_stop != 0x45 && wdt_stop != wdt_start) |
377 | release_region(wdt_stop, 1); | |
1da177e4 | 378 | err_out_region1: |
1780de41 | 379 | release_region(wdt_start, 1); |
1da177e4 LT |
380 | err_out: |
381 | return rc; | |
382 | } | |
383 | ||
384 | module_init(sbc60xxwdt_init); | |
385 | module_exit(sbc60xxwdt_unload); | |
386 | ||
387 | MODULE_AUTHOR("Jakob Oestergaard <jakob@unthought.net>"); | |
388 | MODULE_DESCRIPTION("60xx Single Board Computer Watchdog Timer driver"); | |
389 | MODULE_LICENSE("GPL"); |