Commit | Line | Data |
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d0173278 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
1da177e4 LT |
2 | /* |
3 | * IB700 Single Board Computer WDT driver | |
4 | * | |
5 | * (c) Copyright 2001 Charles Howes <chowes@vsol.net> | |
6 | * | |
c9d7710e WVS |
7 | * Based on advantechwdt.c which is based on acquirewdt.c which |
8 | * is based on wdt.c. | |
1da177e4 LT |
9 | * |
10 | * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl> | |
11 | * | |
12 | * Based on acquirewdt.c which is based on wdt.c. | |
13 | * Original copyright messages: | |
14 | * | |
29fa0586 AC |
15 | * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>, |
16 | * All Rights Reserved. | |
1da177e4 | 17 | * |
1da177e4 LT |
18 | * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide |
19 | * warranty for any of this software. This material is provided | |
20 | * "AS-IS" and at no charge. | |
21 | * | |
29fa0586 | 22 | * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> |
1da177e4 | 23 | * |
c9d7710e WVS |
24 | * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> |
25 | * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT | |
26 | * Added timeout module option to override default | |
1da177e4 LT |
27 | * |
28 | */ | |
29 | ||
27c766aa JP |
30 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
31 | ||
1da177e4 LT |
32 | #include <linux/module.h> |
33 | #include <linux/types.h> | |
34 | #include <linux/miscdevice.h> | |
35 | #include <linux/watchdog.h> | |
36 | #include <linux/ioport.h> | |
1da177e4 | 37 | #include <linux/fs.h> |
1da177e4 LT |
38 | #include <linux/init.h> |
39 | #include <linux/spinlock.h> | |
40 | #include <linux/moduleparam.h> | |
745ac1ea | 41 | #include <linux/platform_device.h> |
2e43ba73 AC |
42 | #include <linux/io.h> |
43 | #include <linux/uaccess.h> | |
089ab079 | 44 | |
1da177e4 | 45 | |
745ac1ea | 46 | static struct platform_device *ibwdt_platform_device; |
1da177e4 | 47 | static unsigned long ibwdt_is_open; |
c7dfd0cc | 48 | static DEFINE_SPINLOCK(ibwdt_lock); |
1da177e4 LT |
49 | static char expect_close; |
50 | ||
745ac1ea WVS |
51 | /* Module information */ |
52 | #define DRV_NAME "ib700wdt" | |
1da177e4 LT |
53 | |
54 | /* | |
55 | * | |
56 | * Watchdog Timer Configuration | |
57 | * | |
58 | * The function of the watchdog timer is to reset the system | |
59 | * automatically and is defined at I/O port 0443H. To enable the | |
60 | * watchdog timer and allow the system to reset, write I/O port 0443H. | |
61 | * To disable the timer, write I/O port 0441H for the system to stop the | |
62 | * watchdog function. The timer has a tolerance of 20% for its | |
63 | * intervals. | |
64 | * | |
65 | * The following describes how the timer should be programmed. | |
66 | * | |
67 | * Enabling Watchdog: | |
68 | * MOV AX,000FH (Choose the values from 0 to F) | |
69 | * MOV DX,0443H | |
70 | * OUT DX,AX | |
71 | * | |
72 | * Disabling Watchdog: | |
73 | * MOV AX,000FH (Any value is fine.) | |
74 | * MOV DX,0441H | |
75 | * OUT DX,AX | |
76 | * | |
77 | * Watchdog timer control table: | |
78 | * Level Value Time/sec | Level Value Time/sec | |
79 | * 1 F 0 | 9 7 16 | |
80 | * 2 E 2 | 10 6 18 | |
81 | * 3 D 4 | 11 5 20 | |
82 | * 4 C 6 | 12 4 22 | |
83 | * 5 B 8 | 13 3 24 | |
84 | * 6 A 10 | 14 2 26 | |
85 | * 7 9 12 | 15 1 28 | |
86 | * 8 8 14 | 16 0 30 | |
87 | * | |
88 | */ | |
89 | ||
1da177e4 LT |
90 | #define WDT_STOP 0x441 |
91 | #define WDT_START 0x443 | |
92 | ||
93 | /* Default timeout */ | |
794db26f WVS |
94 | #define WATCHDOG_TIMEOUT 30 /* 30 seconds +/- 20% */ |
95 | static int timeout = WATCHDOG_TIMEOUT; /* in seconds */ | |
96 | module_param(timeout, int, 0); | |
97 | MODULE_PARM_DESC(timeout, | |
98 | "Watchdog timeout in seconds. 0<= timeout <=30, default=" | |
99 | __MODULE_STRING(WATCHDOG_TIMEOUT) "."); | |
1da177e4 | 100 | |
86a1e189 WVS |
101 | static bool nowayout = WATCHDOG_NOWAYOUT; |
102 | module_param(nowayout, bool, 0); | |
2e43ba73 AC |
103 | MODULE_PARM_DESC(nowayout, |
104 | "Watchdog cannot be stopped once started (default=" | |
105 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
1da177e4 LT |
106 | |
107 | ||
108 | /* | |
35d55c94 | 109 | * Watchdog Operations |
1da177e4 LT |
110 | */ |
111 | ||
7944d3a5 | 112 | static void ibwdt_ping(void) |
1da177e4 | 113 | { |
794db26f WVS |
114 | int wd_margin = 15 - ((timeout + 1) / 2); |
115 | ||
e42162a4 WVS |
116 | spin_lock(&ibwdt_lock); |
117 | ||
1da177e4 LT |
118 | /* Write a watchdog value */ |
119 | outb_p(wd_margin, WDT_START); | |
e42162a4 WVS |
120 | |
121 | spin_unlock(&ibwdt_lock); | |
1da177e4 LT |
122 | } |
123 | ||
7944d3a5 | 124 | static void ibwdt_disable(void) |
35d55c94 | 125 | { |
e42162a4 | 126 | spin_lock(&ibwdt_lock); |
35d55c94 | 127 | outb_p(0, WDT_STOP); |
e42162a4 | 128 | spin_unlock(&ibwdt_lock); |
35d55c94 WVS |
129 | } |
130 | ||
7944d3a5 | 131 | static int ibwdt_set_heartbeat(int t) |
35d55c94 | 132 | { |
794db26f | 133 | if (t < 0 || t > 30) |
35d55c94 WVS |
134 | return -EINVAL; |
135 | ||
794db26f | 136 | timeout = t; |
35d55c94 WVS |
137 | return 0; |
138 | } | |
139 | ||
140 | /* | |
141 | * /dev/watchdog handling | |
142 | */ | |
143 | ||
2e43ba73 AC |
144 | static ssize_t ibwdt_write(struct file *file, const char __user *buf, |
145 | size_t count, loff_t *ppos) | |
1da177e4 LT |
146 | { |
147 | if (count) { | |
148 | if (!nowayout) { | |
149 | size_t i; | |
150 | ||
151 | /* In case it was set long ago */ | |
152 | expect_close = 0; | |
153 | ||
154 | for (i = 0; i != count; i++) { | |
155 | char c; | |
156 | if (get_user(c, buf + i)) | |
157 | return -EFAULT; | |
158 | if (c == 'V') | |
159 | expect_close = 42; | |
160 | } | |
161 | } | |
162 | ibwdt_ping(); | |
163 | } | |
164 | return count; | |
165 | } | |
166 | ||
2e43ba73 | 167 | static long ibwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
1da177e4 | 168 | { |
35d55c94 | 169 | int new_margin; |
1da177e4 LT |
170 | void __user *argp = (void __user *)arg; |
171 | int __user *p = argp; | |
172 | ||
42747d71 | 173 | static const struct watchdog_info ident = { |
2e43ba73 AC |
174 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
175 | | WDIOF_MAGICCLOSE, | |
1da177e4 LT |
176 | .firmware_version = 1, |
177 | .identity = "IB700 WDT", | |
178 | }; | |
179 | ||
180 | switch (cmd) { | |
181 | case WDIOC_GETSUPPORT: | |
2e43ba73 AC |
182 | if (copy_to_user(argp, &ident, sizeof(ident))) |
183 | return -EFAULT; | |
184 | break; | |
1da177e4 LT |
185 | |
186 | case WDIOC_GETSTATUS: | |
c9d7710e | 187 | case WDIOC_GETBOOTSTATUS: |
2e43ba73 | 188 | return put_user(0, p); |
1da177e4 | 189 | |
e42162a4 WVS |
190 | case WDIOC_SETOPTIONS: |
191 | { | |
2e43ba73 | 192 | int options, retval = -EINVAL; |
e42162a4 | 193 | |
2e43ba73 AC |
194 | if (get_user(options, p)) |
195 | return -EFAULT; | |
e42162a4 | 196 | |
2e43ba73 AC |
197 | if (options & WDIOS_DISABLECARD) { |
198 | ibwdt_disable(); | |
199 | retval = 0; | |
200 | } | |
201 | if (options & WDIOS_ENABLECARD) { | |
202 | ibwdt_ping(); | |
203 | retval = 0; | |
204 | } | |
205 | return retval; | |
e42162a4 | 206 | } |
0c06090c WVS |
207 | case WDIOC_KEEPALIVE: |
208 | ibwdt_ping(); | |
209 | break; | |
210 | ||
211 | case WDIOC_SETTIMEOUT: | |
212 | if (get_user(new_margin, p)) | |
213 | return -EFAULT; | |
214 | if (ibwdt_set_heartbeat(new_margin)) | |
215 | return -EINVAL; | |
216 | ibwdt_ping(); | |
bd490f82 | 217 | fallthrough; |
0c06090c WVS |
218 | |
219 | case WDIOC_GETTIMEOUT: | |
794db26f | 220 | return put_user(timeout, p); |
0c06090c | 221 | |
1da177e4 | 222 | default: |
2e43ba73 | 223 | return -ENOTTY; |
1da177e4 LT |
224 | } |
225 | return 0; | |
226 | } | |
227 | ||
2e43ba73 | 228 | static int ibwdt_open(struct inode *inode, struct file *file) |
1da177e4 | 229 | { |
2e43ba73 | 230 | if (test_and_set_bit(0, &ibwdt_is_open)) |
1da177e4 | 231 | return -EBUSY; |
1da177e4 LT |
232 | if (nowayout) |
233 | __module_get(THIS_MODULE); | |
234 | ||
235 | /* Activate */ | |
236 | ibwdt_ping(); | |
c5bf68fe | 237 | return stream_open(inode, file); |
1da177e4 LT |
238 | } |
239 | ||
7944d3a5 | 240 | static int ibwdt_close(struct inode *inode, struct file *file) |
1da177e4 | 241 | { |
c9d7710e | 242 | if (expect_close == 42) { |
35d55c94 | 243 | ibwdt_disable(); |
c9d7710e | 244 | } else { |
27c766aa | 245 | pr_crit("WDT device closed unexpectedly. WDT will not stop!\n"); |
c9d7710e WVS |
246 | ibwdt_ping(); |
247 | } | |
1da177e4 LT |
248 | clear_bit(0, &ibwdt_is_open); |
249 | expect_close = 0; | |
1da177e4 LT |
250 | return 0; |
251 | } | |
252 | ||
1da177e4 LT |
253 | /* |
254 | * Kernel Interfaces | |
255 | */ | |
256 | ||
62322d25 | 257 | static const struct file_operations ibwdt_fops = { |
1da177e4 LT |
258 | .owner = THIS_MODULE, |
259 | .llseek = no_llseek, | |
260 | .write = ibwdt_write, | |
2e43ba73 | 261 | .unlocked_ioctl = ibwdt_ioctl, |
b6dfb247 | 262 | .compat_ioctl = compat_ptr_ioctl, |
1da177e4 LT |
263 | .open = ibwdt_open, |
264 | .release = ibwdt_close, | |
265 | }; | |
266 | ||
267 | static struct miscdevice ibwdt_miscdev = { | |
268 | .minor = WATCHDOG_MINOR, | |
269 | .name = "watchdog", | |
270 | .fops = &ibwdt_fops, | |
271 | }; | |
272 | ||
f6e48039 WVS |
273 | /* |
274 | * Init & exit routines | |
275 | */ | |
276 | ||
996735ff | 277 | static int __init ibwdt_probe(struct platform_device *dev) |
1da177e4 LT |
278 | { |
279 | int res; | |
280 | ||
1da177e4 LT |
281 | #if WDT_START != WDT_STOP |
282 | if (!request_region(WDT_STOP, 1, "IB700 WDT")) { | |
27c766aa | 283 | pr_err("STOP method I/O %X is not available\n", WDT_STOP); |
1da177e4 LT |
284 | res = -EIO; |
285 | goto out_nostopreg; | |
286 | } | |
287 | #endif | |
288 | ||
289 | if (!request_region(WDT_START, 1, "IB700 WDT")) { | |
27c766aa | 290 | pr_err("START method I/O %X is not available\n", WDT_START); |
1da177e4 LT |
291 | res = -EIO; |
292 | goto out_nostartreg; | |
293 | } | |
f6e48039 | 294 | |
794db26f WVS |
295 | /* Check that the heartbeat value is within it's range ; |
296 | * if not reset to the default */ | |
297 | if (ibwdt_set_heartbeat(timeout)) { | |
298 | ibwdt_set_heartbeat(WATCHDOG_TIMEOUT); | |
27c766aa | 299 | pr_info("timeout value must be 0<=x<=30, using %d\n", timeout); |
794db26f WVS |
300 | } |
301 | ||
f6e48039 WVS |
302 | res = misc_register(&ibwdt_miscdev); |
303 | if (res) { | |
27c766aa | 304 | pr_err("failed to register misc device\n"); |
f6e48039 WVS |
305 | goto out_nomisc; |
306 | } | |
1da177e4 LT |
307 | return 0; |
308 | ||
f6e48039 | 309 | out_nomisc: |
1da177e4 LT |
310 | release_region(WDT_START, 1); |
311 | out_nostartreg: | |
312 | #if WDT_START != WDT_STOP | |
313 | release_region(WDT_STOP, 1); | |
314 | #endif | |
315 | out_nostopreg: | |
1da177e4 LT |
316 | return res; |
317 | } | |
318 | ||
4b12b896 | 319 | static int ibwdt_remove(struct platform_device *dev) |
1da177e4 LT |
320 | { |
321 | misc_deregister(&ibwdt_miscdev); | |
2e43ba73 | 322 | release_region(WDT_START, 1); |
1da177e4 | 323 | #if WDT_START != WDT_STOP |
2e43ba73 | 324 | release_region(WDT_STOP, 1); |
1da177e4 | 325 | #endif |
745ac1ea WVS |
326 | return 0; |
327 | } | |
328 | ||
35fcf538 WVS |
329 | static void ibwdt_shutdown(struct platform_device *dev) |
330 | { | |
331 | /* Turn the WDT off if we have a soft shutdown */ | |
332 | ibwdt_disable(); | |
333 | } | |
334 | ||
745ac1ea | 335 | static struct platform_driver ibwdt_driver = { |
82268714 | 336 | .remove = ibwdt_remove, |
35fcf538 | 337 | .shutdown = ibwdt_shutdown, |
745ac1ea | 338 | .driver = { |
745ac1ea WVS |
339 | .name = DRV_NAME, |
340 | }, | |
341 | }; | |
342 | ||
343 | static int __init ibwdt_init(void) | |
344 | { | |
345 | int err; | |
346 | ||
27c766aa | 347 | pr_info("WDT driver for IB700 single board computer initialising\n"); |
745ac1ea | 348 | |
2e43ba73 AC |
349 | ibwdt_platform_device = platform_device_register_simple(DRV_NAME, |
350 | -1, NULL, 0); | |
996735ff JD |
351 | if (IS_ERR(ibwdt_platform_device)) |
352 | return PTR_ERR(ibwdt_platform_device); | |
353 | ||
354 | err = platform_driver_probe(&ibwdt_driver, ibwdt_probe); | |
355 | if (err) | |
356 | goto unreg_platform_device; | |
745ac1ea WVS |
357 | |
358 | return 0; | |
359 | ||
996735ff JD |
360 | unreg_platform_device: |
361 | platform_device_unregister(ibwdt_platform_device); | |
745ac1ea WVS |
362 | return err; |
363 | } | |
364 | ||
365 | static void __exit ibwdt_exit(void) | |
366 | { | |
367 | platform_device_unregister(ibwdt_platform_device); | |
368 | platform_driver_unregister(&ibwdt_driver); | |
27c766aa | 369 | pr_info("Watchdog Module Unloaded\n"); |
1da177e4 LT |
370 | } |
371 | ||
372 | module_init(ibwdt_init); | |
373 | module_exit(ibwdt_exit); | |
374 | ||
375 | MODULE_AUTHOR("Charles Howes <chowes@vsol.net>"); | |
376 | MODULE_DESCRIPTION("IB700 SBC watchdog driver"); | |
377 | MODULE_LICENSE("GPL"); | |
1da177e4 LT |
378 | |
379 | /* end of ib700wdt.c */ |