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mixcomwd.c
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1 /*
2  * MixCom Watchdog: A Simple Hardware Watchdog Device
3  * Based on Softdog driver by Alan Cox and PC Watchdog driver by Ken Hollis
4  *
5  * Author: Gergely Madarasz <[email protected]>
6  *
7  * Copyright (c) 1999 ITConsult-Pro Co. <[email protected]>
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License
11  * as published by the Free Software Foundation; either version
12  * 2 of the License, or (at your option) any later version.
13  *
14  * Version 0.1 (99/04/15):
15  * - first version
16  *
17  * Version 0.2 (99/06/16):
18  * - added kernel timer watchdog ping after close
19  * since the hardware does not support watchdog shutdown
20  *
21  * Version 0.3 (99/06/21):
22  * - added WDIOC_GETSTATUS and WDIOC_GETSUPPORT ioctl calls
23  *
24  * Version 0.3.1 (99/06/22):
25  * - allow module removal while internal timer is active,
26  * print warning about probable reset
27  *
28  * Version 0.4 (99/11/15):
29  * - support for one more type board
30  *
31  * Version 0.5 (2001/12/14) Matt Domsch <[email protected]>
32  * - added nowayout module option to override
33  * CONFIG_WATCHDOG_NOWAYOUT
34  *
35  * Version 0.6 (2002/04/12): Rob Radez <[email protected]>
36  * - make mixcomwd_opened unsigned,
37  * removed lock_kernel/unlock_kernel from mixcomwd_release,
38  * modified ioctl a bit to conform to API
39  *
40  */
41 
42 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
43 
44 #define VERSION "0.6"
45 #define WATCHDOG_NAME "mixcomwd"
46 
47 #include <linux/module.h>
48 #include <linux/moduleparam.h>
49 #include <linux/types.h>
50 #include <linux/miscdevice.h>
51 #include <linux/ioport.h>
52 #include <linux/watchdog.h>
53 #include <linux/fs.h>
54 #include <linux/reboot.h>
55 #include <linux/init.h>
56 #include <linux/jiffies.h>
57 #include <linux/timer.h>
58 #include <linux/uaccess.h>
59 #include <linux/io.h>
60 
61 /*
62  * We have two types of cards that can be probed:
63  * 1) The Mixcom cards: these cards can be found at addresses
64  * 0x180, 0x280, 0x380 with an additional offset of 0xc10.
65  * (Or 0xd90, 0xe90, 0xf90).
66  * 2) The FlashCOM cards: these cards can be set up at
67  * 0x300 -> 0x378, in 0x8 jumps with an offset of 0x04.
68  * (Or 0x304 -> 0x37c in 0x8 jumps).
69  * Each card has it's own ID.
70  */
71 #define MIXCOM_ID 0x11
72 #define FLASHCOM_ID 0x18
73 static struct {
74  int ioport;
75  int id;
76 } mixcomwd_io_info[] __devinitdata = {
77  /* The Mixcom cards */
78  {0x0d90, MIXCOM_ID},
79  {0x0e90, MIXCOM_ID},
80  {0x0f90, MIXCOM_ID},
81  /* The FlashCOM cards */
82  {0x0304, FLASHCOM_ID},
83  {0x030c, FLASHCOM_ID},
84  {0x0314, FLASHCOM_ID},
85  {0x031c, FLASHCOM_ID},
86  {0x0324, FLASHCOM_ID},
87  {0x032c, FLASHCOM_ID},
88  {0x0334, FLASHCOM_ID},
89  {0x033c, FLASHCOM_ID},
90  {0x0344, FLASHCOM_ID},
91  {0x034c, FLASHCOM_ID},
92  {0x0354, FLASHCOM_ID},
93  {0x035c, FLASHCOM_ID},
94  {0x0364, FLASHCOM_ID},
95  {0x036c, FLASHCOM_ID},
96  {0x0374, FLASHCOM_ID},
97  {0x037c, FLASHCOM_ID},
98  /* The end of the list */
99  {0x0000, 0},
100 };
101 
102 static void mixcomwd_timerfun(unsigned long d);
103 
104 static unsigned long mixcomwd_opened; /* long req'd for setbit --RR */
105 
106 static int watchdog_port;
107 static int mixcomwd_timer_alive;
108 static DEFINE_TIMER(mixcomwd_timer, mixcomwd_timerfun, 0, 0);
109 static char expect_close;
110 
111 static bool nowayout = WATCHDOG_NOWAYOUT;
112 module_param(nowayout, bool, 0);
113 MODULE_PARM_DESC(nowayout,
114  "Watchdog cannot be stopped once started (default="
116 
117 static void mixcomwd_ping(void)
118 {
119  outb_p(55, watchdog_port);
120  return;
121 }
122 
123 static void mixcomwd_timerfun(unsigned long d)
124 {
125  mixcomwd_ping();
126  mod_timer(&mixcomwd_timer, jiffies + 5 * HZ);
127 }
128 
129 /*
130  * Allow only one person to hold it open
131  */
132 
133 static int mixcomwd_open(struct inode *inode, struct file *file)
134 {
135  if (test_and_set_bit(0, &mixcomwd_opened))
136  return -EBUSY;
137 
138  mixcomwd_ping();
139 
140  if (nowayout)
141  /*
142  * fops_get() code via open() has already done
143  * a try_module_get() so it is safe to do the
144  * __module_get().
145  */
146  __module_get(THIS_MODULE);
147  else {
148  if (mixcomwd_timer_alive) {
149  del_timer(&mixcomwd_timer);
150  mixcomwd_timer_alive = 0;
151  }
152  }
153  return nonseekable_open(inode, file);
154 }
155 
156 static int mixcomwd_release(struct inode *inode, struct file *file)
157 {
158  if (expect_close == 42) {
159  if (mixcomwd_timer_alive) {
160  pr_err("release called while internal timer alive\n");
161  return -EBUSY;
162  }
163  mixcomwd_timer_alive = 1;
164  mod_timer(&mixcomwd_timer, jiffies + 5 * HZ);
165  } else
166  pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");
167 
168  clear_bit(0, &mixcomwd_opened);
169  expect_close = 0;
170  return 0;
171 }
172 
173 
174 static ssize_t mixcomwd_write(struct file *file, const char __user *data,
175  size_t len, loff_t *ppos)
176 {
177  if (len) {
178  if (!nowayout) {
179  size_t i;
180 
181  /* In case it was set long ago */
182  expect_close = 0;
183 
184  for (i = 0; i != len; i++) {
185  char c;
186  if (get_user(c, data + i))
187  return -EFAULT;
188  if (c == 'V')
189  expect_close = 42;
190  }
191  }
192  mixcomwd_ping();
193  }
194  return len;
195 }
196 
197 static long mixcomwd_ioctl(struct file *file,
198  unsigned int cmd, unsigned long arg)
199 {
200  void __user *argp = (void __user *)arg;
201  int __user *p = argp;
202  int status;
203  static const struct watchdog_info ident = {
205  .firmware_version = 1,
206  .identity = "MixCOM watchdog",
207  };
208 
209  switch (cmd) {
210  case WDIOC_GETSUPPORT:
211  if (copy_to_user(argp, &ident, sizeof(ident)))
212  return -EFAULT;
213  break;
214  case WDIOC_GETSTATUS:
215  status = mixcomwd_opened;
216  if (!nowayout)
217  status |= mixcomwd_timer_alive;
218  return put_user(status, p);
219  case WDIOC_GETBOOTSTATUS:
220  return put_user(0, p);
221  case WDIOC_KEEPALIVE:
222  mixcomwd_ping();
223  break;
224  default:
225  return -ENOTTY;
226  }
227  return 0;
228 }
229 
230 static const struct file_operations mixcomwd_fops = {
231  .owner = THIS_MODULE,
232  .llseek = no_llseek,
233  .write = mixcomwd_write,
234  .unlocked_ioctl = mixcomwd_ioctl,
235  .open = mixcomwd_open,
236  .release = mixcomwd_release,
237 };
238 
239 static struct miscdevice mixcomwd_miscdev = {
240  .minor = WATCHDOG_MINOR,
241  .name = "watchdog",
242  .fops = &mixcomwd_fops,
243 };
244 
245 static int __init checkcard(int port, int card_id)
246 {
247  int id;
248 
249  if (!request_region(port, 1, "MixCOM watchdog"))
250  return 0;
251 
252  id = inb_p(port);
253  if (card_id == MIXCOM_ID)
254  id &= 0x3f;
255 
256  if (id != card_id) {
257  release_region(port, 1);
258  return 0;
259  }
260  return 1;
261 }
262 
263 static int __init mixcomwd_init(void)
264 {
265  int i, ret, found = 0;
266 
267  for (i = 0; !found && mixcomwd_io_info[i].ioport != 0; i++) {
268  if (checkcard(mixcomwd_io_info[i].ioport,
269  mixcomwd_io_info[i].id)) {
270  found = 1;
271  watchdog_port = mixcomwd_io_info[i].ioport;
272  }
273  }
274 
275  if (!found) {
276  pr_err("No card detected, or port not available\n");
277  return -ENODEV;
278  }
279 
280  ret = misc_register(&mixcomwd_miscdev);
281  if (ret) {
282  pr_err("cannot register miscdev on minor=%d (err=%d)\n",
283  WATCHDOG_MINOR, ret);
284  goto error_misc_register_watchdog;
285  }
286 
287  pr_info("MixCOM watchdog driver v%s, watchdog port at 0x%3x\n",
288  VERSION, watchdog_port);
289 
290  return 0;
291 
292 error_misc_register_watchdog:
293  release_region(watchdog_port, 1);
294  watchdog_port = 0x0000;
295  return ret;
296 }
297 
298 static void __exit mixcomwd_exit(void)
299 {
300  if (!nowayout) {
301  if (mixcomwd_timer_alive) {
302  pr_warn("I quit now, hardware will probably reboot!\n");
303  del_timer_sync(&mixcomwd_timer);
304  mixcomwd_timer_alive = 0;
305  }
306  }
307  misc_deregister(&mixcomwd_miscdev);
308  release_region(watchdog_port, 1);
309 }
310 
311 module_init(mixcomwd_init);
312 module_exit(mixcomwd_exit);
313 
314 MODULE_AUTHOR("Gergely Madarasz <[email protected]>");
315 MODULE_DESCRIPTION("MixCom Watchdog driver");
317 MODULE_LICENSE("GPL");