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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* |
3 | * 60xx Single Board Computer Watchdog Timer driver for Linux 2.2.x | |
4 | * | |
143a2e54 | 5 | * Based on acquirewdt.c by Alan Cox. |
1da177e4 | 6 | * |
1da177e4 LT |
7 | * The author does NOT admit liability nor provide warranty for |
8 | * any of this software. This material is provided "AS-IS" in | |
9 | * the hope that it may be useful for others. | |
10 | * | |
11 | * (c) Copyright 2000 Jakob Oestergaard <jakob@unthought.net> | |
12 | * | |
13 | * 12/4 - 2000 [Initial revision] | |
14 | * 25/4 - 2000 Added /dev/watchdog support | |
1780de41 AC |
15 | * 09/5 - 2001 [smj@oro.net] fixed fop_write to "return 1" |
16 | * on success | |
1da177e4 LT |
17 | * 12/4 - 2002 [rob@osinvestor.com] eliminate fop_read |
18 | * fix possible wdt_is_open race | |
19 | * add CONFIG_WATCHDOG_NOWAYOUT support | |
20 | * remove lock_kernel/unlock_kernel pairs | |
21 | * added KERN_* to printk's | |
22 | * got rid of extraneous comments | |
1780de41 AC |
23 | * changed watchdog_info to correctly reflect what |
24 | * the driver offers | |
25 | * added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS, | |
26 | * WDIOC_SETTIMEOUT, WDIOC_GETTIMEOUT, and | |
27 | * WDIOC_SETOPTIONS ioctls | |
1da177e4 LT |
28 | * 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces |
29 | * use module_param | |
1780de41 AC |
30 | * made timeout (the emulated heartbeat) a |
31 | * module_param | |
1da177e4 LT |
32 | * made the keepalive ping an internal subroutine |
33 | * made wdt_stop and wdt_start module params | |
34 | * added extra printk's for startup problems | |
35 | * added MODULE_AUTHOR and MODULE_DESCRIPTION info | |
36 | * | |
1da177e4 LT |
37 | * This WDT driver is different from the other Linux WDT |
38 | * drivers in the following ways: | |
39 | * *) The driver will ping the watchdog by itself, because this | |
40 | * particular WDT has a very short timeout (one second) and it | |
41 | * would be insane to count on any userspace daemon always | |
42 | * getting scheduled within that time frame. | |
1da177e4 LT |
43 | */ |
44 | ||
27c766aa JP |
45 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
46 | ||
1da177e4 LT |
47 | #include <linux/module.h> |
48 | #include <linux/moduleparam.h> | |
49 | #include <linux/types.h> | |
50 | #include <linux/timer.h> | |
51 | #include <linux/jiffies.h> | |
52 | #include <linux/miscdevice.h> | |
53 | #include <linux/watchdog.h> | |
54 | #include <linux/fs.h> | |
55 | #include <linux/ioport.h> | |
56 | #include <linux/notifier.h> | |
57 | #include <linux/reboot.h> | |
58 | #include <linux/init.h> | |
1780de41 AC |
59 | #include <linux/io.h> |
60 | #include <linux/uaccess.h> | |
1da177e4 | 61 | |
1da177e4 LT |
62 | |
63 | #define OUR_NAME "sbc60xxwdt" | |
64 | #define PFX OUR_NAME ": " | |
65 | ||
66 | /* | |
67 | * You must set these - The driver cannot probe for the settings | |
68 | */ | |
69 | ||
70 | static int wdt_stop = 0x45; | |
71 | module_param(wdt_stop, int, 0); | |
72 | MODULE_PARM_DESC(wdt_stop, "SBC60xx WDT 'stop' io port (default 0x45)"); | |
73 | ||
74 | static int wdt_start = 0x443; | |
75 | module_param(wdt_start, int, 0); | |
76 | MODULE_PARM_DESC(wdt_start, "SBC60xx WDT 'start' io port (default 0x443)"); | |
77 | ||
78 | /* | |
79 | * The 60xx board can use watchdog timeout values from one second | |
80 | * to several minutes. The default is one second, so if we reset | |
81 | * the watchdog every ~250ms we should be safe. | |
82 | */ | |
83 | ||
84 | #define WDT_INTERVAL (HZ/4+1) | |
85 | ||
86 | /* | |
87 | * We must not require too good response from the userspace daemon. | |
88 | * Here we require the userspace daemon to send us a heartbeat | |
89 | * char to /dev/watchdog every 30 seconds. | |
90 | * If the daemon pulses us every 25 seconds, we can still afford | |
91 | * a 5 second scheduling delay on the (high priority) daemon. That | |
92 | * should be sufficient for a box under any load. | |
93 | */ | |
94 | ||
95 | #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ | |
1780de41 AC |
96 | static int timeout = WATCHDOG_TIMEOUT; /* in seconds, multiplied by HZ to |
97 | get seconds to wait for a ping */ | |
1da177e4 | 98 | module_param(timeout, int, 0); |
1780de41 AC |
99 | MODULE_PARM_DESC(timeout, |
100 | "Watchdog timeout in seconds. (1<=timeout<=3600, default=" | |
101 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
1da177e4 | 102 | |
86a1e189 WVS |
103 | static bool nowayout = WATCHDOG_NOWAYOUT; |
104 | module_param(nowayout, bool, 0); | |
1780de41 AC |
105 | MODULE_PARM_DESC(nowayout, |
106 | "Watchdog cannot be stopped once started (default=" | |
107 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
1da177e4 | 108 | |
24ed960a | 109 | static void wdt_timer_ping(struct timer_list *); |
1d27e3e2 | 110 | static DEFINE_TIMER(timer, wdt_timer_ping); |
1da177e4 LT |
111 | static unsigned long next_heartbeat; |
112 | static unsigned long wdt_is_open; | |
113 | static char wdt_expect_close; | |
114 | ||
115 | /* | |
116 | * Whack the dog | |
117 | */ | |
118 | ||
24ed960a | 119 | static void wdt_timer_ping(struct timer_list *unused) |
1da177e4 LT |
120 | { |
121 | /* If we got a heartbeat pulse within the WDT_US_INTERVAL | |
122 | * we agree to ping the WDT | |
123 | */ | |
1780de41 | 124 | if (time_before(jiffies, next_heartbeat)) { |
1da177e4 LT |
125 | /* Ping the WDT by reading from wdt_start */ |
126 | inb_p(wdt_start); | |
127 | /* Re-set the timer interval */ | |
82eb7c50 | 128 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
1780de41 | 129 | } else |
27c766aa | 130 | pr_warn("Heartbeat lost! Will not ping the watchdog\n"); |
1da177e4 LT |
131 | } |
132 | ||
133 | /* | |
134 | * Utility routines | |
135 | */ | |
136 | ||
137 | static void wdt_startup(void) | |
138 | { | |
139 | next_heartbeat = jiffies + (timeout * HZ); | |
140 | ||
141 | /* Start the timer */ | |
82eb7c50 | 142 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
27c766aa | 143 | pr_info("Watchdog timer is now enabled\n"); |
1da177e4 LT |
144 | } |
145 | ||
146 | static void wdt_turnoff(void) | |
147 | { | |
148 | /* Stop the timer */ | |
149 | del_timer(&timer); | |
150 | inb_p(wdt_stop); | |
27c766aa | 151 | pr_info("Watchdog timer is now disabled...\n"); |
1da177e4 LT |
152 | } |
153 | ||
154 | static void wdt_keepalive(void) | |
155 | { | |
156 | /* user land ping */ | |
157 | next_heartbeat = jiffies + (timeout * HZ); | |
158 | } | |
159 | ||
160 | /* | |
161 | * /dev/watchdog handling | |
162 | */ | |
163 | ||
1780de41 AC |
164 | static ssize_t fop_write(struct file *file, const char __user *buf, |
165 | size_t count, loff_t *ppos) | |
1da177e4 LT |
166 | { |
167 | /* See if we got the magic character 'V' and reload the timer */ | |
1780de41 AC |
168 | if (count) { |
169 | if (!nowayout) { | |
1da177e4 LT |
170 | size_t ofs; |
171 | ||
1780de41 AC |
172 | /* note: just in case someone wrote the |
173 | magic character five months ago... */ | |
1da177e4 LT |
174 | wdt_expect_close = 0; |
175 | ||
1780de41 AC |
176 | /* scan to see whether or not we got the |
177 | magic character */ | |
178 | for (ofs = 0; ofs != count; ofs++) { | |
1da177e4 | 179 | char c; |
7944d3a5 | 180 | if (get_user(c, buf + ofs)) |
1da177e4 | 181 | return -EFAULT; |
1780de41 | 182 | if (c == 'V') |
1da177e4 LT |
183 | wdt_expect_close = 42; |
184 | } | |
185 | } | |
186 | ||
1780de41 AC |
187 | /* Well, anyhow someone wrote to us, we should |
188 | return that favour */ | |
1da177e4 LT |
189 | wdt_keepalive(); |
190 | } | |
191 | return count; | |
192 | } | |
193 | ||
1780de41 | 194 | static int fop_open(struct inode *inode, struct file *file) |
1da177e4 | 195 | { |
1da177e4 | 196 | /* Just in case we're already talking to someone... */ |
1780de41 | 197 | if (test_and_set_bit(0, &wdt_is_open)) |
1da177e4 LT |
198 | return -EBUSY; |
199 | ||
200 | if (nowayout) | |
201 | __module_get(THIS_MODULE); | |
202 | ||
203 | /* Good, fire up the show */ | |
204 | wdt_startup(); | |
c5bf68fe | 205 | return stream_open(inode, file); |
1da177e4 LT |
206 | } |
207 | ||
1780de41 | 208 | static int fop_close(struct inode *inode, struct file *file) |
1da177e4 | 209 | { |
1780de41 | 210 | if (wdt_expect_close == 42) |
1da177e4 LT |
211 | wdt_turnoff(); |
212 | else { | |
213 | del_timer(&timer); | |
27c766aa | 214 | pr_crit("device file closed unexpectedly. Will not stop the WDT!\n"); |
1da177e4 LT |
215 | } |
216 | clear_bit(0, &wdt_is_open); | |
217 | wdt_expect_close = 0; | |
218 | return 0; | |
219 | } | |
220 | ||
1780de41 | 221 | static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
1da177e4 LT |
222 | { |
223 | void __user *argp = (void __user *)arg; | |
224 | int __user *p = argp; | |
1780de41 AC |
225 | static const struct watchdog_info ident = { |
226 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | | |
227 | WDIOF_MAGICCLOSE, | |
1da177e4 LT |
228 | .firmware_version = 1, |
229 | .identity = "SBC60xx", | |
230 | }; | |
231 | ||
1780de41 | 232 | switch (cmd) { |
1780de41 | 233 | case WDIOC_GETSUPPORT: |
7944d3a5 | 234 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; |
1780de41 AC |
235 | case WDIOC_GETSTATUS: |
236 | case WDIOC_GETBOOTSTATUS: | |
237 | return put_user(0, p); | |
1780de41 | 238 | case WDIOC_SETOPTIONS: |
1da177e4 | 239 | { |
1780de41 AC |
240 | int new_options, retval = -EINVAL; |
241 | if (get_user(new_options, p)) | |
242 | return -EFAULT; | |
243 | if (new_options & WDIOS_DISABLECARD) { | |
244 | wdt_turnoff(); | |
245 | retval = 0; | |
1da177e4 | 246 | } |
1780de41 AC |
247 | if (new_options & WDIOS_ENABLECARD) { |
248 | wdt_startup(); | |
249 | retval = 0; | |
1da177e4 | 250 | } |
1780de41 AC |
251 | return retval; |
252 | } | |
0c06090c WVS |
253 | case WDIOC_KEEPALIVE: |
254 | wdt_keepalive(); | |
255 | return 0; | |
1780de41 AC |
256 | case WDIOC_SETTIMEOUT: |
257 | { | |
258 | int new_timeout; | |
259 | if (get_user(new_timeout, p)) | |
260 | return -EFAULT; | |
261 | /* arbitrary upper limit */ | |
262 | if (new_timeout < 1 || new_timeout > 3600) | |
263 | return -EINVAL; | |
264 | ||
265 | timeout = new_timeout; | |
266 | wdt_keepalive(); | |
1780de41 | 267 | } |
3612b87d | 268 | /* Fall through */ |
1780de41 AC |
269 | case WDIOC_GETTIMEOUT: |
270 | return put_user(timeout, p); | |
0c06090c WVS |
271 | default: |
272 | return -ENOTTY; | |
1da177e4 LT |
273 | } |
274 | } | |
275 | ||
62322d25 | 276 | static const struct file_operations wdt_fops = { |
1da177e4 LT |
277 | .owner = THIS_MODULE, |
278 | .llseek = no_llseek, | |
279 | .write = fop_write, | |
280 | .open = fop_open, | |
281 | .release = fop_close, | |
1780de41 | 282 | .unlocked_ioctl = fop_ioctl, |
1da177e4 LT |
283 | }; |
284 | ||
285 | static struct miscdevice wdt_miscdev = { | |
286 | .minor = WATCHDOG_MINOR, | |
287 | .name = "watchdog", | |
288 | .fops = &wdt_fops, | |
289 | }; | |
290 | ||
291 | /* | |
292 | * Notifier for system down | |
293 | */ | |
294 | ||
295 | static int wdt_notify_sys(struct notifier_block *this, unsigned long code, | |
296 | void *unused) | |
297 | { | |
1780de41 | 298 | if (code == SYS_DOWN || code == SYS_HALT) |
1da177e4 LT |
299 | wdt_turnoff(); |
300 | return NOTIFY_DONE; | |
301 | } | |
302 | ||
303 | /* | |
304 | * The WDT needs to learn about soft shutdowns in order to | |
305 | * turn the timebomb registers off. | |
306 | */ | |
307 | ||
1780de41 | 308 | static struct notifier_block wdt_notifier = { |
1da177e4 LT |
309 | .notifier_call = wdt_notify_sys, |
310 | }; | |
311 | ||
312 | static void __exit sbc60xxwdt_unload(void) | |
313 | { | |
314 | wdt_turnoff(); | |
315 | ||
316 | /* Deregister */ | |
317 | misc_deregister(&wdt_miscdev); | |
318 | ||
319 | unregister_reboot_notifier(&wdt_notifier); | |
320 | if ((wdt_stop != 0x45) && (wdt_stop != wdt_start)) | |
1780de41 AC |
321 | release_region(wdt_stop, 1); |
322 | release_region(wdt_start, 1); | |
1da177e4 LT |
323 | } |
324 | ||
325 | static int __init sbc60xxwdt_init(void) | |
326 | { | |
327 | int rc = -EBUSY; | |
328 | ||
1780de41 | 329 | if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */ |
1da177e4 | 330 | timeout = WATCHDOG_TIMEOUT; |
27c766aa JP |
331 | pr_info("timeout value must be 1 <= x <= 3600, using %d\n", |
332 | timeout); | |
1780de41 | 333 | } |
1da177e4 | 334 | |
1780de41 | 335 | if (!request_region(wdt_start, 1, "SBC 60XX WDT")) { |
27c766aa | 336 | pr_err("I/O address 0x%04x already in use\n", wdt_start); |
1da177e4 LT |
337 | rc = -EIO; |
338 | goto err_out; | |
339 | } | |
340 | ||
341 | /* We cannot reserve 0x45 - the kernel already has! */ | |
1780de41 AC |
342 | if (wdt_stop != 0x45 && wdt_stop != wdt_start) { |
343 | if (!request_region(wdt_stop, 1, "SBC 60XX WDT")) { | |
27c766aa | 344 | pr_err("I/O address 0x%04x already in use\n", wdt_stop); |
1da177e4 LT |
345 | rc = -EIO; |
346 | goto err_out_region1; | |
347 | } | |
348 | } | |
349 | ||
c6cb13ae | 350 | rc = register_reboot_notifier(&wdt_notifier); |
1780de41 | 351 | if (rc) { |
27c766aa | 352 | pr_err("cannot register reboot notifier (err=%d)\n", rc); |
1da177e4 LT |
353 | goto err_out_region2; |
354 | } | |
355 | ||
c6cb13ae | 356 | rc = misc_register(&wdt_miscdev); |
1780de41 | 357 | if (rc) { |
27c766aa JP |
358 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
359 | wdt_miscdev.minor, rc); | |
c6cb13ae | 360 | goto err_out_reboot; |
1da177e4 | 361 | } |
27c766aa JP |
362 | pr_info("WDT driver for 60XX single board computer initialised. timeout=%d sec (nowayout=%d)\n", |
363 | timeout, nowayout); | |
1da177e4 LT |
364 | |
365 | return 0; | |
366 | ||
c6cb13ae WVS |
367 | err_out_reboot: |
368 | unregister_reboot_notifier(&wdt_notifier); | |
1da177e4 | 369 | err_out_region2: |
1780de41 AC |
370 | if (wdt_stop != 0x45 && wdt_stop != wdt_start) |
371 | release_region(wdt_stop, 1); | |
1da177e4 | 372 | err_out_region1: |
1780de41 | 373 | release_region(wdt_start, 1); |
1da177e4 LT |
374 | err_out: |
375 | return rc; | |
376 | } | |
377 | ||
378 | module_init(sbc60xxwdt_init); | |
379 | module_exit(sbc60xxwdt_unload); | |
380 | ||
381 | MODULE_AUTHOR("Jakob Oestergaard <jakob@unthought.net>"); | |
382 | MODULE_DESCRIPTION("60xx Single Board Computer Watchdog Timer driver"); | |
383 | MODULE_LICENSE("GPL"); |