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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * ICP Wafer 5823 Single Board Computer WDT driver
4 * http://www.icpamerica.com/wafer_5823.php
5 * May also work on other similar models
6 *
7 * (c) Copyright 2002 Justin Cormack <justin@street-vision.com>
8 *
9 * Release 0.02
10 *
11 * Based on advantechwdt.c which is based on wdt.c.
12 * Original copyright messages:
13 *
14 * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
15 * All Rights Reserved.
16 *
17 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
18 * warranty for any of this software. This material is provided
19 * "AS-IS" and at no charge.
20 *
21 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
22 *
23 */
24
25#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
26
27#include <linux/module.h>
28#include <linux/moduleparam.h>
29#include <linux/miscdevice.h>
30#include <linux/watchdog.h>
31#include <linux/fs.h>
32#include <linux/ioport.h>
33#include <linux/notifier.h>
34#include <linux/reboot.h>
35#include <linux/init.h>
36#include <linux/spinlock.h>
37#include <linux/io.h>
38#include <linux/uaccess.h>
39
40#define WATCHDOG_NAME "Wafer 5823 WDT"
41#define PFX WATCHDOG_NAME ": "
42#define WD_TIMO 60 /* 60 sec default timeout */
43
44static unsigned long wafwdt_is_open;
45static char expect_close;
46static DEFINE_SPINLOCK(wafwdt_lock);
47
48/*
49 * You must set these - there is no sane way to probe for this board.
50 *
51 * To enable, write the timeout value in seconds (1 to 255) to I/O
52 * port WDT_START, then read the port to start the watchdog. To pat
53 * the dog, read port WDT_STOP to stop the timer, then read WDT_START
54 * to restart it again.
55 */
56
57static int wdt_stop = 0x843;
58static int wdt_start = 0x443;
59
60static int timeout = WD_TIMO; /* in seconds */
61module_param(timeout, int, 0);
62MODULE_PARM_DESC(timeout,
63 "Watchdog timeout in seconds. 1 <= timeout <= 255, default="
64 __MODULE_STRING(WD_TIMO) ".");
65
66static bool nowayout = WATCHDOG_NOWAYOUT;
67module_param(nowayout, bool, 0);
68MODULE_PARM_DESC(nowayout,
69 "Watchdog cannot be stopped once started (default="
70 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
71
72static void wafwdt_ping(void)
73{
74 /* pat watchdog */
75 spin_lock(&wafwdt_lock);
76 inb_p(wdt_stop);
77 inb_p(wdt_start);
78 spin_unlock(&wafwdt_lock);
79}
80
81static void wafwdt_start(void)
82{
83 /* start up watchdog */
84 outb_p(timeout, wdt_start);
85 inb_p(wdt_start);
86}
87
88static void wafwdt_stop(void)
89{
90 /* stop watchdog */
91 inb_p(wdt_stop);
92}
93
94static ssize_t wafwdt_write(struct file *file, const char __user *buf,
95 size_t count, loff_t *ppos)
96{
97 /* See if we got the magic character 'V' and reload the timer */
98 if (count) {
99 if (!nowayout) {
100 size_t i;
101
102 /* In case it was set long ago */
103 expect_close = 0;
104
105 /* scan to see whether or not we got the magic
106 character */
107 for (i = 0; i != count; i++) {
108 char c;
109 if (get_user(c, buf + i))
110 return -EFAULT;
111 if (c == 'V')
112 expect_close = 42;
113 }
114 }
115 /* Well, anyhow someone wrote to us, we should
116 return that favour */
117 wafwdt_ping();
118 }
119 return count;
120}
121
122static long wafwdt_ioctl(struct file *file, unsigned int cmd,
123 unsigned long arg)
124{
125 int new_timeout;
126 void __user *argp = (void __user *)arg;
127 int __user *p = argp;
128 static const struct watchdog_info ident = {
129 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
130 WDIOF_MAGICCLOSE,
131 .firmware_version = 1,
132 .identity = "Wafer 5823 WDT",
133 };
134
135 switch (cmd) {
136 case WDIOC_GETSUPPORT:
137 if (copy_to_user(argp, &ident, sizeof(ident)))
138 return -EFAULT;
139 break;
140
141 case WDIOC_GETSTATUS:
142 case WDIOC_GETBOOTSTATUS:
143 return put_user(0, p);
144
145 case WDIOC_SETOPTIONS:
146 {
147 int options, retval = -EINVAL;
148
149 if (get_user(options, p))
150 return -EFAULT;
151
152 if (options & WDIOS_DISABLECARD) {
153 wafwdt_stop();
154 retval = 0;
155 }
156
157 if (options & WDIOS_ENABLECARD) {
158 wafwdt_start();
159 retval = 0;
160 }
161
162 return retval;
163 }
164
165 case WDIOC_KEEPALIVE:
166 wafwdt_ping();
167 break;
168
169 case WDIOC_SETTIMEOUT:
170 if (get_user(new_timeout, p))
171 return -EFAULT;
172 if ((new_timeout < 1) || (new_timeout > 255))
173 return -EINVAL;
174 timeout = new_timeout;
175 wafwdt_stop();
176 wafwdt_start();
177 fallthrough;
178 case WDIOC_GETTIMEOUT:
179 return put_user(timeout, p);
180
181 default:
182 return -ENOTTY;
183 }
184 return 0;
185}
186
187static int wafwdt_open(struct inode *inode, struct file *file)
188{
189 if (test_and_set_bit(0, &wafwdt_is_open))
190 return -EBUSY;
191
192 /*
193 * Activate
194 */
195 wafwdt_start();
196 return stream_open(inode, file);
197}
198
199static int wafwdt_close(struct inode *inode, struct file *file)
200{
201 if (expect_close == 42)
202 wafwdt_stop();
203 else {
204 pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");
205 wafwdt_ping();
206 }
207 clear_bit(0, &wafwdt_is_open);
208 expect_close = 0;
209 return 0;
210}
211
212/*
213 * Notifier for system down
214 */
215
216static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code,
217 void *unused)
218{
219 if (code == SYS_DOWN || code == SYS_HALT)
220 wafwdt_stop();
221 return NOTIFY_DONE;
222}
223
224/*
225 * Kernel Interfaces
226 */
227
228static const struct file_operations wafwdt_fops = {
229 .owner = THIS_MODULE,
230 .llseek = no_llseek,
231 .write = wafwdt_write,
232 .unlocked_ioctl = wafwdt_ioctl,
233 .compat_ioctl = compat_ptr_ioctl,
234 .open = wafwdt_open,
235 .release = wafwdt_close,
236};
237
238static struct miscdevice wafwdt_miscdev = {
239 .minor = WATCHDOG_MINOR,
240 .name = "watchdog",
241 .fops = &wafwdt_fops,
242};
243
244/*
245 * The WDT needs to learn about soft shutdowns in order to
246 * turn the timebomb registers off.
247 */
248
249static struct notifier_block wafwdt_notifier = {
250 .notifier_call = wafwdt_notify_sys,
251};
252
253static int __init wafwdt_init(void)
254{
255 int ret;
256
257 pr_info("WDT driver for Wafer 5823 single board computer initialising\n");
258
259 if (timeout < 1 || timeout > 255) {
260 timeout = WD_TIMO;
261 pr_info("timeout value must be 1 <= x <= 255, using %d\n",
262 timeout);
263 }
264
265 if (wdt_stop != wdt_start) {
266 if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
267 pr_err("I/O address 0x%04x already in use\n", wdt_stop);
268 ret = -EIO;
269 goto error;
270 }
271 }
272
273 if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
274 pr_err("I/O address 0x%04x already in use\n", wdt_start);
275 ret = -EIO;
276 goto error2;
277 }
278
279 ret = register_reboot_notifier(&wafwdt_notifier);
280 if (ret != 0) {
281 pr_err("cannot register reboot notifier (err=%d)\n", ret);
282 goto error3;
283 }
284
285 ret = misc_register(&wafwdt_miscdev);
286 if (ret != 0) {
287 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
288 WATCHDOG_MINOR, ret);
289 goto error4;
290 }
291
292 pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
293 timeout, nowayout);
294
295 return ret;
296error4:
297 unregister_reboot_notifier(&wafwdt_notifier);
298error3:
299 release_region(wdt_start, 1);
300error2:
301 if (wdt_stop != wdt_start)
302 release_region(wdt_stop, 1);
303error:
304 return ret;
305}
306
307static void __exit wafwdt_exit(void)
308{
309 misc_deregister(&wafwdt_miscdev);
310 unregister_reboot_notifier(&wafwdt_notifier);
311 if (wdt_stop != wdt_start)
312 release_region(wdt_stop, 1);
313 release_region(wdt_start, 1);
314}
315
316module_init(wafwdt_init);
317module_exit(wafwdt_exit);
318
319MODULE_AUTHOR("Justin Cormack");
320MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
321MODULE_LICENSE("GPL");
322
323/* end of wafer5823wdt.c */
1/*
2 * ICP Wafer 5823 Single Board Computer WDT driver
3 * http://www.icpamerica.com/wafer_5823.php
4 * May also work on other similar models
5 *
6 * (c) Copyright 2002 Justin Cormack <justin@street-vision.com>
7 *
8 * Release 0.02
9 *
10 * Based on advantechwdt.c which is based on wdt.c.
11 * Original copyright messages:
12 *
13 * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
14 * All Rights Reserved.
15 *
16 * This program is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU General Public License
18 * as published by the Free Software Foundation; either version
19 * 2 of the License, or (at your option) any later version.
20 *
21 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
22 * warranty for any of this software. This material is provided
23 * "AS-IS" and at no charge.
24 *
25 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
26 *
27 */
28
29#include <linux/module.h>
30#include <linux/moduleparam.h>
31#include <linux/miscdevice.h>
32#include <linux/watchdog.h>
33#include <linux/fs.h>
34#include <linux/ioport.h>
35#include <linux/notifier.h>
36#include <linux/reboot.h>
37#include <linux/init.h>
38#include <linux/spinlock.h>
39#include <linux/io.h>
40#include <linux/uaccess.h>
41
42#define WATCHDOG_NAME "Wafer 5823 WDT"
43#define PFX WATCHDOG_NAME ": "
44#define WD_TIMO 60 /* 60 sec default timeout */
45
46static unsigned long wafwdt_is_open;
47static char expect_close;
48static DEFINE_SPINLOCK(wafwdt_lock);
49
50/*
51 * You must set these - there is no sane way to probe for this board.
52 *
53 * To enable, write the timeout value in seconds (1 to 255) to I/O
54 * port WDT_START, then read the port to start the watchdog. To pat
55 * the dog, read port WDT_STOP to stop the timer, then read WDT_START
56 * to restart it again.
57 */
58
59static int wdt_stop = 0x843;
60static int wdt_start = 0x443;
61
62static int timeout = WD_TIMO; /* in seconds */
63module_param(timeout, int, 0);
64MODULE_PARM_DESC(timeout,
65 "Watchdog timeout in seconds. 1 <= timeout <= 255, default="
66 __MODULE_STRING(WD_TIMO) ".");
67
68static int nowayout = WATCHDOG_NOWAYOUT;
69module_param(nowayout, int, 0);
70MODULE_PARM_DESC(nowayout,
71 "Watchdog cannot be stopped once started (default="
72 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
73
74static void wafwdt_ping(void)
75{
76 /* pat watchdog */
77 spin_lock(&wafwdt_lock);
78 inb_p(wdt_stop);
79 inb_p(wdt_start);
80 spin_unlock(&wafwdt_lock);
81}
82
83static void wafwdt_start(void)
84{
85 /* start up watchdog */
86 outb_p(timeout, wdt_start);
87 inb_p(wdt_start);
88}
89
90static void wafwdt_stop(void)
91{
92 /* stop watchdog */
93 inb_p(wdt_stop);
94}
95
96static ssize_t wafwdt_write(struct file *file, const char __user *buf,
97 size_t count, loff_t *ppos)
98{
99 /* See if we got the magic character 'V' and reload the timer */
100 if (count) {
101 if (!nowayout) {
102 size_t i;
103
104 /* In case it was set long ago */
105 expect_close = 0;
106
107 /* scan to see whether or not we got the magic
108 character */
109 for (i = 0; i != count; i++) {
110 char c;
111 if (get_user(c, buf + i))
112 return -EFAULT;
113 if (c == 'V')
114 expect_close = 42;
115 }
116 }
117 /* Well, anyhow someone wrote to us, we should
118 return that favour */
119 wafwdt_ping();
120 }
121 return count;
122}
123
124static long wafwdt_ioctl(struct file *file, unsigned int cmd,
125 unsigned long arg)
126{
127 int new_timeout;
128 void __user *argp = (void __user *)arg;
129 int __user *p = argp;
130 static const struct watchdog_info ident = {
131 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
132 WDIOF_MAGICCLOSE,
133 .firmware_version = 1,
134 .identity = "Wafer 5823 WDT",
135 };
136
137 switch (cmd) {
138 case WDIOC_GETSUPPORT:
139 if (copy_to_user(argp, &ident, sizeof(ident)))
140 return -EFAULT;
141 break;
142
143 case WDIOC_GETSTATUS:
144 case WDIOC_GETBOOTSTATUS:
145 return put_user(0, p);
146
147 case WDIOC_SETOPTIONS:
148 {
149 int options, retval = -EINVAL;
150
151 if (get_user(options, p))
152 return -EFAULT;
153
154 if (options & WDIOS_DISABLECARD) {
155 wafwdt_start();
156 retval = 0;
157 }
158
159 if (options & WDIOS_ENABLECARD) {
160 wafwdt_stop();
161 retval = 0;
162 }
163
164 return retval;
165 }
166
167 case WDIOC_KEEPALIVE:
168 wafwdt_ping();
169 break;
170
171 case WDIOC_SETTIMEOUT:
172 if (get_user(new_timeout, p))
173 return -EFAULT;
174 if ((new_timeout < 1) || (new_timeout > 255))
175 return -EINVAL;
176 timeout = new_timeout;
177 wafwdt_stop();
178 wafwdt_start();
179 /* Fall */
180 case WDIOC_GETTIMEOUT:
181 return put_user(timeout, p);
182
183 default:
184 return -ENOTTY;
185 }
186 return 0;
187}
188
189static int wafwdt_open(struct inode *inode, struct file *file)
190{
191 if (test_and_set_bit(0, &wafwdt_is_open))
192 return -EBUSY;
193
194 /*
195 * Activate
196 */
197 wafwdt_start();
198 return nonseekable_open(inode, file);
199}
200
201static int wafwdt_close(struct inode *inode, struct file *file)
202{
203 if (expect_close == 42)
204 wafwdt_stop();
205 else {
206 printk(KERN_CRIT PFX
207 "WDT device closed unexpectedly. WDT will not stop!\n");
208 wafwdt_ping();
209 }
210 clear_bit(0, &wafwdt_is_open);
211 expect_close = 0;
212 return 0;
213}
214
215/*
216 * Notifier for system down
217 */
218
219static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code,
220 void *unused)
221{
222 if (code == SYS_DOWN || code == SYS_HALT)
223 wafwdt_stop();
224 return NOTIFY_DONE;
225}
226
227/*
228 * Kernel Interfaces
229 */
230
231static const struct file_operations wafwdt_fops = {
232 .owner = THIS_MODULE,
233 .llseek = no_llseek,
234 .write = wafwdt_write,
235 .unlocked_ioctl = wafwdt_ioctl,
236 .open = wafwdt_open,
237 .release = wafwdt_close,
238};
239
240static struct miscdevice wafwdt_miscdev = {
241 .minor = WATCHDOG_MINOR,
242 .name = "watchdog",
243 .fops = &wafwdt_fops,
244};
245
246/*
247 * The WDT needs to learn about soft shutdowns in order to
248 * turn the timebomb registers off.
249 */
250
251static struct notifier_block wafwdt_notifier = {
252 .notifier_call = wafwdt_notify_sys,
253};
254
255static int __init wafwdt_init(void)
256{
257 int ret;
258
259 printk(KERN_INFO
260 "WDT driver for Wafer 5823 single board computer initialising.\n");
261
262 if (timeout < 1 || timeout > 255) {
263 timeout = WD_TIMO;
264 printk(KERN_INFO PFX
265 "timeout value must be 1 <= x <= 255, using %d\n",
266 timeout);
267 }
268
269 if (wdt_stop != wdt_start) {
270 if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
271 printk(KERN_ERR PFX
272 "I/O address 0x%04x already in use\n",
273 wdt_stop);
274 ret = -EIO;
275 goto error;
276 }
277 }
278
279 if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
280 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
281 wdt_start);
282 ret = -EIO;
283 goto error2;
284 }
285
286 ret = register_reboot_notifier(&wafwdt_notifier);
287 if (ret != 0) {
288 printk(KERN_ERR PFX
289 "cannot register reboot notifier (err=%d)\n", ret);
290 goto error3;
291 }
292
293 ret = misc_register(&wafwdt_miscdev);
294 if (ret != 0) {
295 printk(KERN_ERR PFX
296 "cannot register miscdev on minor=%d (err=%d)\n",
297 WATCHDOG_MINOR, ret);
298 goto error4;
299 }
300
301 printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
302 timeout, nowayout);
303
304 return ret;
305error4:
306 unregister_reboot_notifier(&wafwdt_notifier);
307error3:
308 release_region(wdt_start, 1);
309error2:
310 if (wdt_stop != wdt_start)
311 release_region(wdt_stop, 1);
312error:
313 return ret;
314}
315
316static void __exit wafwdt_exit(void)
317{
318 misc_deregister(&wafwdt_miscdev);
319 unregister_reboot_notifier(&wafwdt_notifier);
320 if (wdt_stop != wdt_start)
321 release_region(wdt_stop, 1);
322 release_region(wdt_start, 1);
323}
324
325module_init(wafwdt_init);
326module_exit(wafwdt_exit);
327
328MODULE_AUTHOR("Justin Cormack");
329MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
330MODULE_LICENSE("GPL");
331MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
332
333/* end of wafer5823wdt.c */