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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * IB700 Single Board Computer WDT driver
4 *
5 * (c) Copyright 2001 Charles Howes <chowes@vsol.net>
6 *
7 * Based on advantechwdt.c which is based on acquirewdt.c which
8 * is based on wdt.c.
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 *
15 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
16 * All Rights Reserved.
17 *
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 *
22 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
23 *
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
27 *
28 */
29
30#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
31
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>
37#include <linux/fs.h>
38#include <linux/init.h>
39#include <linux/spinlock.h>
40#include <linux/moduleparam.h>
41#include <linux/platform_device.h>
42#include <linux/io.h>
43#include <linux/uaccess.h>
44
45
46static struct platform_device *ibwdt_platform_device;
47static unsigned long ibwdt_is_open;
48static DEFINE_SPINLOCK(ibwdt_lock);
49static char expect_close;
50
51/* Module information */
52#define DRV_NAME "ib700wdt"
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
90#define WDT_STOP 0x441
91#define WDT_START 0x443
92
93/* Default timeout */
94#define WATCHDOG_TIMEOUT 30 /* 30 seconds +/- 20% */
95static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
96module_param(timeout, int, 0);
97MODULE_PARM_DESC(timeout,
98 "Watchdog timeout in seconds. 0<= timeout <=30, default="
99 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
100
101static bool nowayout = WATCHDOG_NOWAYOUT;
102module_param(nowayout, bool, 0);
103MODULE_PARM_DESC(nowayout,
104 "Watchdog cannot be stopped once started (default="
105 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
106
107
108/*
109 * Watchdog Operations
110 */
111
112static void ibwdt_ping(void)
113{
114 int wd_margin = 15 - ((timeout + 1) / 2);
115
116 spin_lock(&ibwdt_lock);
117
118 /* Write a watchdog value */
119 outb_p(wd_margin, WDT_START);
120
121 spin_unlock(&ibwdt_lock);
122}
123
124static void ibwdt_disable(void)
125{
126 spin_lock(&ibwdt_lock);
127 outb_p(0, WDT_STOP);
128 spin_unlock(&ibwdt_lock);
129}
130
131static int ibwdt_set_heartbeat(int t)
132{
133 if (t < 0 || t > 30)
134 return -EINVAL;
135
136 timeout = t;
137 return 0;
138}
139
140/*
141 * /dev/watchdog handling
142 */
143
144static ssize_t ibwdt_write(struct file *file, const char __user *buf,
145 size_t count, loff_t *ppos)
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
167static long ibwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
168{
169 int new_margin;
170 void __user *argp = (void __user *)arg;
171 int __user *p = argp;
172
173 static const struct watchdog_info ident = {
174 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
175 | WDIOF_MAGICCLOSE,
176 .firmware_version = 1,
177 .identity = "IB700 WDT",
178 };
179
180 switch (cmd) {
181 case WDIOC_GETSUPPORT:
182 if (copy_to_user(argp, &ident, sizeof(ident)))
183 return -EFAULT;
184 break;
185
186 case WDIOC_GETSTATUS:
187 case WDIOC_GETBOOTSTATUS:
188 return put_user(0, p);
189
190 case WDIOC_SETOPTIONS:
191 {
192 int options, retval = -EINVAL;
193
194 if (get_user(options, p))
195 return -EFAULT;
196
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;
206 }
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();
217 fallthrough;
218
219 case WDIOC_GETTIMEOUT:
220 return put_user(timeout, p);
221
222 default:
223 return -ENOTTY;
224 }
225 return 0;
226}
227
228static int ibwdt_open(struct inode *inode, struct file *file)
229{
230 if (test_and_set_bit(0, &ibwdt_is_open))
231 return -EBUSY;
232 if (nowayout)
233 __module_get(THIS_MODULE);
234
235 /* Activate */
236 ibwdt_ping();
237 return stream_open(inode, file);
238}
239
240static int ibwdt_close(struct inode *inode, struct file *file)
241{
242 if (expect_close == 42) {
243 ibwdt_disable();
244 } else {
245 pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");
246 ibwdt_ping();
247 }
248 clear_bit(0, &ibwdt_is_open);
249 expect_close = 0;
250 return 0;
251}
252
253/*
254 * Kernel Interfaces
255 */
256
257static const struct file_operations ibwdt_fops = {
258 .owner = THIS_MODULE,
259 .llseek = no_llseek,
260 .write = ibwdt_write,
261 .unlocked_ioctl = ibwdt_ioctl,
262 .compat_ioctl = compat_ptr_ioctl,
263 .open = ibwdt_open,
264 .release = ibwdt_close,
265};
266
267static struct miscdevice ibwdt_miscdev = {
268 .minor = WATCHDOG_MINOR,
269 .name = "watchdog",
270 .fops = &ibwdt_fops,
271};
272
273/*
274 * Init & exit routines
275 */
276
277static int __init ibwdt_probe(struct platform_device *dev)
278{
279 int res;
280
281#if WDT_START != WDT_STOP
282 if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
283 pr_err("STOP method I/O %X is not available\n", WDT_STOP);
284 res = -EIO;
285 goto out_nostopreg;
286 }
287#endif
288
289 if (!request_region(WDT_START, 1, "IB700 WDT")) {
290 pr_err("START method I/O %X is not available\n", WDT_START);
291 res = -EIO;
292 goto out_nostartreg;
293 }
294
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);
299 pr_info("timeout value must be 0<=x<=30, using %d\n", timeout);
300 }
301
302 res = misc_register(&ibwdt_miscdev);
303 if (res) {
304 pr_err("failed to register misc device\n");
305 goto out_nomisc;
306 }
307 return 0;
308
309out_nomisc:
310 release_region(WDT_START, 1);
311out_nostartreg:
312#if WDT_START != WDT_STOP
313 release_region(WDT_STOP, 1);
314#endif
315out_nostopreg:
316 return res;
317}
318
319static int ibwdt_remove(struct platform_device *dev)
320{
321 misc_deregister(&ibwdt_miscdev);
322 release_region(WDT_START, 1);
323#if WDT_START != WDT_STOP
324 release_region(WDT_STOP, 1);
325#endif
326 return 0;
327}
328
329static void ibwdt_shutdown(struct platform_device *dev)
330{
331 /* Turn the WDT off if we have a soft shutdown */
332 ibwdt_disable();
333}
334
335static struct platform_driver ibwdt_driver = {
336 .remove = ibwdt_remove,
337 .shutdown = ibwdt_shutdown,
338 .driver = {
339 .name = DRV_NAME,
340 },
341};
342
343static int __init ibwdt_init(void)
344{
345 int err;
346
347 pr_info("WDT driver for IB700 single board computer initialising\n");
348
349 ibwdt_platform_device = platform_device_register_simple(DRV_NAME,
350 -1, NULL, 0);
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;
357
358 return 0;
359
360unreg_platform_device:
361 platform_device_unregister(ibwdt_platform_device);
362 return err;
363}
364
365static void __exit ibwdt_exit(void)
366{
367 platform_device_unregister(ibwdt_platform_device);
368 platform_driver_unregister(&ibwdt_driver);
369 pr_info("Watchdog Module Unloaded\n");
370}
371
372module_init(ibwdt_init);
373module_exit(ibwdt_exit);
374
375MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
376MODULE_DESCRIPTION("IB700 SBC watchdog driver");
377MODULE_LICENSE("GPL");
378
379/* end of ib700wdt.c */
1/*
2 * IB700 Single Board Computer WDT driver
3 *
4 * (c) Copyright 2001 Charles Howes <chowes@vsol.net>
5 *
6 * Based on advantechwdt.c which is based on acquirewdt.c which
7 * is based on wdt.c.
8 *
9 * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
10 *
11 * Based on acquirewdt.c which is based on wdt.c.
12 * Original copyright messages:
13 *
14 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
15 * All Rights Reserved.
16 *
17 * This program is free software; you can redistribute it and/or
18 * modify it under the terms of the GNU General Public License
19 * as published by the Free Software Foundation; either version
20 * 2 of the License, or (at your option) any later version.
21 *
22 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
23 * warranty for any of this software. This material is provided
24 * "AS-IS" and at no charge.
25 *
26 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
27 *
28 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
29 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
30 * Added timeout module option to override default
31 *
32 */
33
34#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
35
36#include <linux/module.h>
37#include <linux/types.h>
38#include <linux/miscdevice.h>
39#include <linux/watchdog.h>
40#include <linux/ioport.h>
41#include <linux/fs.h>
42#include <linux/init.h>
43#include <linux/spinlock.h>
44#include <linux/moduleparam.h>
45#include <linux/platform_device.h>
46#include <linux/io.h>
47#include <linux/uaccess.h>
48
49
50static struct platform_device *ibwdt_platform_device;
51static unsigned long ibwdt_is_open;
52static DEFINE_SPINLOCK(ibwdt_lock);
53static char expect_close;
54
55/* Module information */
56#define DRV_NAME "ib700wdt"
57
58/*
59 *
60 * Watchdog Timer Configuration
61 *
62 * The function of the watchdog timer is to reset the system
63 * automatically and is defined at I/O port 0443H. To enable the
64 * watchdog timer and allow the system to reset, write I/O port 0443H.
65 * To disable the timer, write I/O port 0441H for the system to stop the
66 * watchdog function. The timer has a tolerance of 20% for its
67 * intervals.
68 *
69 * The following describes how the timer should be programmed.
70 *
71 * Enabling Watchdog:
72 * MOV AX,000FH (Choose the values from 0 to F)
73 * MOV DX,0443H
74 * OUT DX,AX
75 *
76 * Disabling Watchdog:
77 * MOV AX,000FH (Any value is fine.)
78 * MOV DX,0441H
79 * OUT DX,AX
80 *
81 * Watchdog timer control table:
82 * Level Value Time/sec | Level Value Time/sec
83 * 1 F 0 | 9 7 16
84 * 2 E 2 | 10 6 18
85 * 3 D 4 | 11 5 20
86 * 4 C 6 | 12 4 22
87 * 5 B 8 | 13 3 24
88 * 6 A 10 | 14 2 26
89 * 7 9 12 | 15 1 28
90 * 8 8 14 | 16 0 30
91 *
92 */
93
94#define WDT_STOP 0x441
95#define WDT_START 0x443
96
97/* Default timeout */
98#define WATCHDOG_TIMEOUT 30 /* 30 seconds +/- 20% */
99static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
100module_param(timeout, int, 0);
101MODULE_PARM_DESC(timeout,
102 "Watchdog timeout in seconds. 0<= timeout <=30, default="
103 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
104
105static bool nowayout = WATCHDOG_NOWAYOUT;
106module_param(nowayout, bool, 0);
107MODULE_PARM_DESC(nowayout,
108 "Watchdog cannot be stopped once started (default="
109 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
110
111
112/*
113 * Watchdog Operations
114 */
115
116static void ibwdt_ping(void)
117{
118 int wd_margin = 15 - ((timeout + 1) / 2);
119
120 spin_lock(&ibwdt_lock);
121
122 /* Write a watchdog value */
123 outb_p(wd_margin, WDT_START);
124
125 spin_unlock(&ibwdt_lock);
126}
127
128static void ibwdt_disable(void)
129{
130 spin_lock(&ibwdt_lock);
131 outb_p(0, WDT_STOP);
132 spin_unlock(&ibwdt_lock);
133}
134
135static int ibwdt_set_heartbeat(int t)
136{
137 if (t < 0 || t > 30)
138 return -EINVAL;
139
140 timeout = t;
141 return 0;
142}
143
144/*
145 * /dev/watchdog handling
146 */
147
148static ssize_t ibwdt_write(struct file *file, const char __user *buf,
149 size_t count, loff_t *ppos)
150{
151 if (count) {
152 if (!nowayout) {
153 size_t i;
154
155 /* In case it was set long ago */
156 expect_close = 0;
157
158 for (i = 0; i != count; i++) {
159 char c;
160 if (get_user(c, buf + i))
161 return -EFAULT;
162 if (c == 'V')
163 expect_close = 42;
164 }
165 }
166 ibwdt_ping();
167 }
168 return count;
169}
170
171static long ibwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
172{
173 int new_margin;
174 void __user *argp = (void __user *)arg;
175 int __user *p = argp;
176
177 static const struct watchdog_info ident = {
178 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
179 | WDIOF_MAGICCLOSE,
180 .firmware_version = 1,
181 .identity = "IB700 WDT",
182 };
183
184 switch (cmd) {
185 case WDIOC_GETSUPPORT:
186 if (copy_to_user(argp, &ident, sizeof(ident)))
187 return -EFAULT;
188 break;
189
190 case WDIOC_GETSTATUS:
191 case WDIOC_GETBOOTSTATUS:
192 return put_user(0, p);
193
194 case WDIOC_SETOPTIONS:
195 {
196 int options, retval = -EINVAL;
197
198 if (get_user(options, p))
199 return -EFAULT;
200
201 if (options & WDIOS_DISABLECARD) {
202 ibwdt_disable();
203 retval = 0;
204 }
205 if (options & WDIOS_ENABLECARD) {
206 ibwdt_ping();
207 retval = 0;
208 }
209 return retval;
210 }
211 case WDIOC_KEEPALIVE:
212 ibwdt_ping();
213 break;
214
215 case WDIOC_SETTIMEOUT:
216 if (get_user(new_margin, p))
217 return -EFAULT;
218 if (ibwdt_set_heartbeat(new_margin))
219 return -EINVAL;
220 ibwdt_ping();
221 /* fall through */
222
223 case WDIOC_GETTIMEOUT:
224 return put_user(timeout, p);
225
226 default:
227 return -ENOTTY;
228 }
229 return 0;
230}
231
232static int ibwdt_open(struct inode *inode, struct file *file)
233{
234 if (test_and_set_bit(0, &ibwdt_is_open))
235 return -EBUSY;
236 if (nowayout)
237 __module_get(THIS_MODULE);
238
239 /* Activate */
240 ibwdt_ping();
241 return nonseekable_open(inode, file);
242}
243
244static int ibwdt_close(struct inode *inode, struct file *file)
245{
246 if (expect_close == 42) {
247 ibwdt_disable();
248 } else {
249 pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");
250 ibwdt_ping();
251 }
252 clear_bit(0, &ibwdt_is_open);
253 expect_close = 0;
254 return 0;
255}
256
257/*
258 * Kernel Interfaces
259 */
260
261static const struct file_operations ibwdt_fops = {
262 .owner = THIS_MODULE,
263 .llseek = no_llseek,
264 .write = ibwdt_write,
265 .unlocked_ioctl = ibwdt_ioctl,
266 .open = ibwdt_open,
267 .release = ibwdt_close,
268};
269
270static struct miscdevice ibwdt_miscdev = {
271 .minor = WATCHDOG_MINOR,
272 .name = "watchdog",
273 .fops = &ibwdt_fops,
274};
275
276/*
277 * Init & exit routines
278 */
279
280static int __init ibwdt_probe(struct platform_device *dev)
281{
282 int res;
283
284#if WDT_START != WDT_STOP
285 if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
286 pr_err("STOP method I/O %X is not available\n", WDT_STOP);
287 res = -EIO;
288 goto out_nostopreg;
289 }
290#endif
291
292 if (!request_region(WDT_START, 1, "IB700 WDT")) {
293 pr_err("START method I/O %X is not available\n", WDT_START);
294 res = -EIO;
295 goto out_nostartreg;
296 }
297
298 /* Check that the heartbeat value is within it's range ;
299 * if not reset to the default */
300 if (ibwdt_set_heartbeat(timeout)) {
301 ibwdt_set_heartbeat(WATCHDOG_TIMEOUT);
302 pr_info("timeout value must be 0<=x<=30, using %d\n", timeout);
303 }
304
305 res = misc_register(&ibwdt_miscdev);
306 if (res) {
307 pr_err("failed to register misc device\n");
308 goto out_nomisc;
309 }
310 return 0;
311
312out_nomisc:
313 release_region(WDT_START, 1);
314out_nostartreg:
315#if WDT_START != WDT_STOP
316 release_region(WDT_STOP, 1);
317#endif
318out_nostopreg:
319 return res;
320}
321
322static int ibwdt_remove(struct platform_device *dev)
323{
324 misc_deregister(&ibwdt_miscdev);
325 release_region(WDT_START, 1);
326#if WDT_START != WDT_STOP
327 release_region(WDT_STOP, 1);
328#endif
329 return 0;
330}
331
332static void ibwdt_shutdown(struct platform_device *dev)
333{
334 /* Turn the WDT off if we have a soft shutdown */
335 ibwdt_disable();
336}
337
338static struct platform_driver ibwdt_driver = {
339 .remove = ibwdt_remove,
340 .shutdown = ibwdt_shutdown,
341 .driver = {
342 .name = DRV_NAME,
343 },
344};
345
346static int __init ibwdt_init(void)
347{
348 int err;
349
350 pr_info("WDT driver for IB700 single board computer initialising\n");
351
352 ibwdt_platform_device = platform_device_register_simple(DRV_NAME,
353 -1, NULL, 0);
354 if (IS_ERR(ibwdt_platform_device))
355 return PTR_ERR(ibwdt_platform_device);
356
357 err = platform_driver_probe(&ibwdt_driver, ibwdt_probe);
358 if (err)
359 goto unreg_platform_device;
360
361 return 0;
362
363unreg_platform_device:
364 platform_device_unregister(ibwdt_platform_device);
365 return err;
366}
367
368static void __exit ibwdt_exit(void)
369{
370 platform_device_unregister(ibwdt_platform_device);
371 platform_driver_unregister(&ibwdt_driver);
372 pr_info("Watchdog Module Unloaded\n");
373}
374
375module_init(ibwdt_init);
376module_exit(ibwdt_exit);
377
378MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
379MODULE_DESCRIPTION("IB700 SBC watchdog driver");
380MODULE_LICENSE("GPL");
381
382/* end of ib700wdt.c */