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31#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
32
33#include <linux/module.h>
34#include <linux/moduleparam.h>
35#include <linux/types.h>
36#include <linux/miscdevice.h>
37#include <linux/watchdog.h>
38#include <linux/fs.h>
39#include <linux/ioport.h>
40#include <linux/platform_device.h>
41#include <linux/init.h>
42#include <linux/io.h>
43#include <linux/uaccess.h>
44
45
46#define DRV_NAME "advantechwdt"
47#define WATCHDOG_NAME "Advantech WDT"
48#define WATCHDOG_TIMEOUT 60
49
50
51static struct platform_device *advwdt_platform_device;
52static unsigned long advwdt_is_open;
53static char adv_expect_close;
54
55
56
57
58
59
60
61
62
63
64
65
66static int wdt_stop = 0x443;
67module_param(wdt_stop, int, 0);
68MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
69
70static int wdt_start = 0x443;
71module_param(wdt_start, int, 0);
72MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
73
74static int timeout = WATCHDOG_TIMEOUT;
75module_param(timeout, int, 0);
76MODULE_PARM_DESC(timeout,
77 "Watchdog timeout in seconds. 1<= timeout <=63, default="
78 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
79
80static bool nowayout = WATCHDOG_NOWAYOUT;
81module_param(nowayout, bool, 0);
82MODULE_PARM_DESC(nowayout,
83 "Watchdog cannot be stopped once started (default="
84 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
85
86
87
88
89
90static void advwdt_ping(void)
91{
92
93 outb_p(timeout, wdt_start);
94}
95
96static void advwdt_disable(void)
97{
98 inb_p(wdt_stop);
99}
100
101static int advwdt_set_heartbeat(int t)
102{
103 if (t < 1 || t > 63)
104 return -EINVAL;
105 timeout = t;
106 return 0;
107}
108
109
110
111
112
113static ssize_t advwdt_write(struct file *file, const char __user *buf,
114 size_t count, loff_t *ppos)
115{
116 if (count) {
117 if (!nowayout) {
118 size_t i;
119
120 adv_expect_close = 0;
121
122 for (i = 0; i != count; i++) {
123 char c;
124 if (get_user(c, buf + i))
125 return -EFAULT;
126 if (c == 'V')
127 adv_expect_close = 42;
128 }
129 }
130 advwdt_ping();
131 }
132 return count;
133}
134
135static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
136{
137 int new_timeout;
138 void __user *argp = (void __user *)arg;
139 int __user *p = argp;
140 static const struct watchdog_info ident = {
141 .options = WDIOF_KEEPALIVEPING |
142 WDIOF_SETTIMEOUT |
143 WDIOF_MAGICCLOSE,
144 .firmware_version = 1,
145 .identity = WATCHDOG_NAME,
146 };
147
148 switch (cmd) {
149 case WDIOC_GETSUPPORT:
150 if (copy_to_user(argp, &ident, sizeof(ident)))
151 return -EFAULT;
152 break;
153
154 case WDIOC_GETSTATUS:
155 case WDIOC_GETBOOTSTATUS:
156 return put_user(0, p);
157
158 case WDIOC_SETOPTIONS:
159 {
160 int options, retval = -EINVAL;
161
162 if (get_user(options, p))
163 return -EFAULT;
164 if (options & WDIOS_DISABLECARD) {
165 advwdt_disable();
166 retval = 0;
167 }
168 if (options & WDIOS_ENABLECARD) {
169 advwdt_ping();
170 retval = 0;
171 }
172 return retval;
173 }
174 case WDIOC_KEEPALIVE:
175 advwdt_ping();
176 break;
177
178 case WDIOC_SETTIMEOUT:
179 if (get_user(new_timeout, p))
180 return -EFAULT;
181 if (advwdt_set_heartbeat(new_timeout))
182 return -EINVAL;
183 advwdt_ping();
184
185 case WDIOC_GETTIMEOUT:
186 return put_user(timeout, p);
187 default:
188 return -ENOTTY;
189 }
190 return 0;
191}
192
193static int advwdt_open(struct inode *inode, struct file *file)
194{
195 if (test_and_set_bit(0, &advwdt_is_open))
196 return -EBUSY;
197
198
199
200
201 advwdt_ping();
202 return nonseekable_open(inode, file);
203}
204
205static int advwdt_close(struct inode *inode, struct file *file)
206{
207 if (adv_expect_close == 42) {
208 advwdt_disable();
209 } else {
210 pr_crit("Unexpected close, not stopping watchdog!\n");
211 advwdt_ping();
212 }
213 clear_bit(0, &advwdt_is_open);
214 adv_expect_close = 0;
215 return 0;
216}
217
218
219
220
221
222static const struct file_operations advwdt_fops = {
223 .owner = THIS_MODULE,
224 .llseek = no_llseek,
225 .write = advwdt_write,
226 .unlocked_ioctl = advwdt_ioctl,
227 .open = advwdt_open,
228 .release = advwdt_close,
229};
230
231static struct miscdevice advwdt_miscdev = {
232 .minor = WATCHDOG_MINOR,
233 .name = "watchdog",
234 .fops = &advwdt_fops,
235};
236
237
238
239
240
241static int advwdt_probe(struct platform_device *dev)
242{
243 int ret;
244
245 if (wdt_stop != wdt_start) {
246 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
247 pr_err("I/O address 0x%04x already in use\n",
248 wdt_stop);
249 ret = -EIO;
250 goto out;
251 }
252 }
253
254 if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
255 pr_err("I/O address 0x%04x already in use\n", wdt_start);
256 ret = -EIO;
257 goto unreg_stop;
258 }
259
260
261
262 if (advwdt_set_heartbeat(timeout)) {
263 advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
264 pr_info("timeout value must be 1<=x<=63, using %d\n", timeout);
265 }
266
267 ret = misc_register(&advwdt_miscdev);
268 if (ret != 0) {
269 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
270 WATCHDOG_MINOR, ret);
271 goto unreg_regions;
272 }
273 pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
274 timeout, nowayout);
275out:
276 return ret;
277unreg_regions:
278 release_region(wdt_start, 1);
279unreg_stop:
280 if (wdt_stop != wdt_start)
281 release_region(wdt_stop, 1);
282 goto out;
283}
284
285static int advwdt_remove(struct platform_device *dev)
286{
287 misc_deregister(&advwdt_miscdev);
288 release_region(wdt_start, 1);
289 if (wdt_stop != wdt_start)
290 release_region(wdt_stop, 1);
291
292 return 0;
293}
294
295static void advwdt_shutdown(struct platform_device *dev)
296{
297
298 advwdt_disable();
299}
300
301static struct platform_driver advwdt_driver = {
302 .probe = advwdt_probe,
303 .remove = advwdt_remove,
304 .shutdown = advwdt_shutdown,
305 .driver = {
306 .owner = THIS_MODULE,
307 .name = DRV_NAME,
308 },
309};
310
311static int __init advwdt_init(void)
312{
313 int err;
314
315 pr_info("WDT driver for Advantech single board computer initialising\n");
316
317 err = platform_driver_register(&advwdt_driver);
318 if (err)
319 return err;
320
321 advwdt_platform_device = platform_device_register_simple(DRV_NAME,
322 -1, NULL, 0);
323 if (IS_ERR(advwdt_platform_device)) {
324 err = PTR_ERR(advwdt_platform_device);
325 goto unreg_platform_driver;
326 }
327
328 return 0;
329
330unreg_platform_driver:
331 platform_driver_unregister(&advwdt_driver);
332 return err;
333}
334
335static void __exit advwdt_exit(void)
336{
337 platform_device_unregister(advwdt_platform_device);
338 platform_driver_unregister(&advwdt_driver);
339 pr_info("Watchdog Module Unloaded\n");
340}
341
342module_init(advwdt_init);
343module_exit(advwdt_exit);
344
345MODULE_LICENSE("GPL");
346MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
347MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
348MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
349