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advantechwdt.c
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1 /*
2  * Advantech Single Board Computer WDT driver
3  *
4  * (c) Copyright 2000-2001 Marek Michalkiewicz <[email protected]>
5  *
6  * Based on acquirewdt.c which is based on wdt.c.
7  * Original copyright messages:
8  *
9  * (c) Copyright 1996 Alan Cox <[email protected]>,
10  * All Rights Reserved.
11  *
12  * This program is free software; you can redistribute it and/or
13  * modify it under the terms of the GNU General Public License
14  * as published by the Free Software Foundation; either version
15  * 2 of the License, or (at your option) any later version.
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 <[email protected]>
22  *
23  * 14-Dec-2001 Matt Domsch <[email protected]>
24  * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
25  *
26  * 16-Oct-2002 Rob Radez <[email protected]>
27  * Clean up ioctls, clean up init + exit, add expect close support,
28  * add wdt_start and wdt_stop as parameters.
29  */
30 
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 /* 60 sec default timeout */
49 
50 /* the watchdog platform device */
51 static struct platform_device *advwdt_platform_device;
52 static unsigned long advwdt_is_open;
53 static char adv_expect_close;
54 
55 /*
56  * You must set these - there is no sane way to probe for this board.
57  *
58  * To enable or restart, write the timeout value in seconds (1 to 63)
59  * to I/O port wdt_start. To disable, read I/O port wdt_stop.
60  * Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
61  * check your manual (at least the PCA-6159 seems to be different -
62  * the manual says wdt_stop is 0x43, not 0x443).
63  * (0x43 is also a write-only control register for the 8254 timer!)
64  */
65 
66 static int wdt_stop = 0x443;
67 module_param(wdt_stop, int, 0);
68 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
69 
70 static int wdt_start = 0x443;
71 module_param(wdt_start, int, 0);
72 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
73 
74 static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
75 module_param(timeout, int, 0);
76 MODULE_PARM_DESC(timeout,
77  "Watchdog timeout in seconds. 1<= timeout <=63, default="
79 
80 static bool nowayout = WATCHDOG_NOWAYOUT;
81 module_param(nowayout, bool, 0);
82 MODULE_PARM_DESC(nowayout,
83  "Watchdog cannot be stopped once started (default="
85 
86 /*
87  * Watchdog Operations
88  */
89 
90 static void advwdt_ping(void)
91 {
92  /* Write a watchdog value */
93  outb_p(timeout, wdt_start);
94 }
95 
96 static void advwdt_disable(void)
97 {
98  inb_p(wdt_stop);
99 }
100 
101 static 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  * /dev/watchdog handling
111  */
112 
113 static 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 
135 static 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 |
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  /* Fall */
185  case WDIOC_GETTIMEOUT:
186  return put_user(timeout, p);
187  default:
188  return -ENOTTY;
189  }
190  return 0;
191 }
192 
193 static 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  * Activate
199  */
200 
201  advwdt_ping();
202  return nonseekable_open(inode, file);
203 }
204 
205 static 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  * Kernel Interfaces
220  */
221 
222 static 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 
231 static struct miscdevice advwdt_miscdev = {
232  .minor = WATCHDOG_MINOR,
233  .name = "watchdog",
234  .fops = &advwdt_fops,
235 };
236 
237 /*
238  * Init & exit routines
239  */
240 
241 static int __devinit 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  /* Check that the heartbeat value is within it's range ;
261  * if not reset to the default */
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);
275 out:
276  return ret;
277 unreg_regions:
278  release_region(wdt_start, 1);
279 unreg_stop:
280  if (wdt_stop != wdt_start)
281  release_region(wdt_stop, 1);
282  goto out;
283 }
284 
285 static int __devexit 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 
295 static void advwdt_shutdown(struct platform_device *dev)
296 {
297  /* Turn the WDT off if we have a soft shutdown */
298  advwdt_disable();
299 }
300 
301 static struct platform_driver advwdt_driver = {
302  .probe = advwdt_probe,
303  .remove = __devexit_p(advwdt_remove),
304  .shutdown = advwdt_shutdown,
305  .driver = {
306  .owner = THIS_MODULE,
307  .name = DRV_NAME,
308  },
309 };
310 
311 static 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 
330 unreg_platform_driver:
331  platform_driver_unregister(&advwdt_driver);
332  return err;
333 }
334 
335 static 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 
342 module_init(advwdt_init);
343 module_exit(advwdt_exit);
344 
345 MODULE_LICENSE("GPL");
346 MODULE_AUTHOR("Marek Michalkiewicz <[email protected]>");
347 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");