char: moxa, prevent opening unavailable ports
[linux-2.6] / drivers / watchdog / w83697ug_wdt.c
1 /*
2  *      w83697ug/uf WDT driver
3  *
4  *      (c) Copyright 2008 Flemming Fransen <ff@nrvissing.net>
5  *              reused original code to support w83697ug/uf.
6  *
7  *      Based on w83627hf_wdt.c which is based on advantechwdt.c
8  *      which is based on wdt.c.
9  *      Original copyright messages:
10  *
11  *      (c) Copyright 2007 Vlad Drukker <vlad@storewiz.com>
12  *              added support for W83627THF.
13  *
14  *      (c) Copyright 2003 Pádraig Brady <P@draigBrady.com>
15  *
16  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
17  *
18  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
19  *                              http://www.redhat.com
20  *
21  *      This program is free software; you can redistribute it and/or
22  *      modify it under the terms of the GNU General Public License
23  *      as published by the Free Software Foundation; either version
24  *      2 of the License, or (at your option) any later version.
25  *
26  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
27  *      warranty for any of this software. This material is provided
28  *      "AS-IS" and at no charge.
29  *
30  *      (c) Copyright 1995    Alan Cox <alan@redhat.com>
31  */
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/notifier.h>
41 #include <linux/reboot.h>
42 #include <linux/init.h>
43 #include <linux/spinlock.h>
44 #include <linux/io.h>
45 #include <linux/uaccess.h>
46
47 #include <asm/system.h>
48
49 #define WATCHDOG_NAME "w83697ug/uf WDT"
50 #define PFX WATCHDOG_NAME ": "
51 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
52
53 static unsigned long wdt_is_open;
54 static char expect_close;
55 static DEFINE_SPINLOCK(io_lock);
56
57 static int wdt_io = 0x2e;
58 module_param(wdt_io, int, 0);
59 MODULE_PARM_DESC(wdt_io, "w83697ug/uf WDT io port (default 0x2e)");
60
61 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
62 module_param(timeout, int, 0);
63 MODULE_PARM_DESC(timeout,
64         "Watchdog timeout in seconds. 1<= timeout <=255 (default="
65                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
66
67 static int nowayout = WATCHDOG_NOWAYOUT;
68 module_param(nowayout, int, 0);
69 MODULE_PARM_DESC(nowayout,
70         "Watchdog cannot be stopped once started (default="
71                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
72
73 /*
74  *      Kernel methods.
75  */
76
77 #define WDT_EFER (wdt_io+0)   /* Extended Function Enable Registers */
78 #define WDT_EFIR (wdt_io+0)   /* Extended Function Index Register
79                                                         (same as EFER) */
80 #define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
81
82 static int w83697ug_select_wd_register(void)
83 {
84         unsigned char c;
85         unsigned char version;
86
87         outb_p(0x87, WDT_EFER); /* Enter extended function mode */
88         outb_p(0x87, WDT_EFER); /* Again according to manual */
89
90         outb(0x20, WDT_EFER);   /* check chip version   */
91         version = inb(WDT_EFDR);
92
93         if (version == 0x68) {  /* W83697UG             */
94                 printk(KERN_INFO PFX "Watchdog chip version 0x%02x = "
95                         "W83697UG/UF found at 0x%04x\n", version, wdt_io);
96
97                 outb_p(0x2b, WDT_EFER);
98                 c = inb_p(WDT_EFDR);    /* select WDT0 */
99                 c &= ~0x04;
100                 outb_p(0x2b, WDT_EFER);
101                 outb_p(c, WDT_EFDR);    /* set pin118 to WDT0 */
102
103         } else {
104                 printk(KERN_ERR PFX "No W83697UG/UF could be found\n");
105                 return -ENODEV;
106         }
107
108         outb_p(0x07, WDT_EFER); /* point to logical device number reg */
109         outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
110         outb_p(0x30, WDT_EFER); /* select CR30 */
111         c = inb_p(WDT_EFDR);
112         outb_p(c || 0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
113
114         return 0;
115 }
116
117 static void w83697ug_unselect_wd_register(void)
118 {
119         outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
120 }
121
122 static int w83697ug_init(void)
123 {
124         int ret;
125         unsigned char t;
126
127         ret = w83697ug_select_wd_register();
128         if (ret != 0)
129                 return ret;
130
131         outb_p(0xF6, WDT_EFER); /* Select CRF6 */
132         t = inb_p(WDT_EFDR);    /* read CRF6 */
133         if (t != 0) {
134                 printk(KERN_INFO PFX "Watchdog already running."
135                         " Resetting timeout to %d sec\n", timeout);
136                 outb_p(timeout, WDT_EFDR);    /* Write back to CRF6 */
137         }
138         outb_p(0xF5, WDT_EFER); /* Select CRF5 */
139         t = inb_p(WDT_EFDR);    /* read CRF5 */
140         t &= ~0x0C;             /* set second mode &
141                                         disable keyboard turning off watchdog */
142         outb_p(t, WDT_EFDR);    /* Write back to CRF5 */
143
144         w83697ug_unselect_wd_register();
145         return 0;
146 }
147
148 static void wdt_ctrl(int timeout)
149 {
150         spin_lock(&io_lock);
151
152         if (w83697ug_select_wd_register() < 0)
153                 return;
154
155         outb_p(0xF4, WDT_EFER);    /* Select CRF4 */
156         outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF4 */
157
158         w83697ug_unselect_wd_register();
159
160         spin_unlock(&io_lock);
161 }
162
163 static int wdt_ping(void)
164 {
165         wdt_ctrl(timeout);
166         return 0;
167 }
168
169 static int wdt_disable(void)
170 {
171         wdt_ctrl(0);
172         return 0;
173 }
174
175 static int wdt_set_heartbeat(int t)
176 {
177         if (t < 1 || t > 255)
178                 return -EINVAL;
179
180         timeout = t;
181         return 0;
182 }
183
184 static ssize_t wdt_write(struct file *file, const char __user *buf,
185                                                 size_t count, loff_t *ppos)
186 {
187         if (count) {
188                 if (!nowayout) {
189                         size_t i;
190
191                         expect_close = 0;
192
193                         for (i = 0; i != count; i++) {
194                                 char c;
195                                 if (get_user(c, buf + i))
196                                         return -EFAULT;
197                                 if (c == 'V')
198                                         expect_close = 42;
199                         }
200                 }
201                 wdt_ping();
202         }
203         return count;
204 }
205
206 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
207 {
208         void __user *argp = (void __user *)arg;
209         int __user *p = argp;
210         int new_timeout;
211         static const struct watchdog_info ident = {
212                 .options =              WDIOF_KEEPALIVEPING |
213                                         WDIOF_SETTIMEOUT |
214                                         WDIOF_MAGICCLOSE,
215                 .firmware_version =     1,
216                 .identity =             "W83697UG WDT",
217         };
218
219         switch (cmd) {
220         case WDIOC_GETSUPPORT:
221                 if (copy_to_user(argp, &ident, sizeof(ident)))
222                         return -EFAULT;
223                 break;
224
225         case WDIOC_GETSTATUS:
226         case WDIOC_GETBOOTSTATUS:
227                 return put_user(0, p);
228
229         case WDIOC_SETOPTIONS:
230         {
231                 int options, retval = -EINVAL;
232
233                 if (get_user(options, p))
234                         return -EFAULT;
235
236                 if (options & WDIOS_DISABLECARD) {
237                         wdt_disable();
238                         retval = 0;
239                 }
240
241                 if (options & WDIOS_ENABLECARD) {
242                         wdt_ping();
243                         retval = 0;
244                 }
245
246                 return retval;
247         }
248
249         case WDIOC_KEEPALIVE:
250                 wdt_ping();
251                 break;
252
253         case WDIOC_SETTIMEOUT:
254                 if (get_user(new_timeout, p))
255                         return -EFAULT;
256                 if (wdt_set_heartbeat(new_timeout))
257                         return -EINVAL;
258                 wdt_ping();
259                 /* Fall */
260
261         case WDIOC_GETTIMEOUT:
262                 return put_user(timeout, p);
263
264         default:
265                 return -ENOTTY;
266         }
267         return 0;
268 }
269
270 static int wdt_open(struct inode *inode, struct file *file)
271 {
272         if (test_and_set_bit(0, &wdt_is_open))
273                 return -EBUSY;
274         /*
275          *      Activate
276          */
277
278         wdt_ping();
279         return nonseekable_open(inode, file);
280 }
281
282 static int wdt_close(struct inode *inode, struct file *file)
283 {
284         if (expect_close == 42)
285                 wdt_disable();
286         else {
287                 printk(KERN_CRIT PFX
288                         "Unexpected close, not stopping watchdog!\n");
289                 wdt_ping();
290         }
291         expect_close = 0;
292         clear_bit(0, &wdt_is_open);
293         return 0;
294 }
295
296 /*
297  *      Notifier for system down
298  */
299
300 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
301         void *unused)
302 {
303         if (code == SYS_DOWN || code == SYS_HALT)
304                 wdt_disable();  /* Turn the WDT off */
305
306         return NOTIFY_DONE;
307 }
308
309 /*
310  *      Kernel Interfaces
311  */
312
313 static const struct file_operations wdt_fops = {
314         .owner          = THIS_MODULE,
315         .llseek         = no_llseek,
316         .write          = wdt_write,
317         .unlocked_ioctl = wdt_ioctl,
318         .open           = wdt_open,
319         .release        = wdt_close,
320 };
321
322 static struct miscdevice wdt_miscdev = {
323         .minor = WATCHDOG_MINOR,
324         .name = "watchdog",
325         .fops = &wdt_fops,
326 };
327
328 /*
329  *      The WDT needs to learn about soft shutdowns in order to
330  *      turn the timebomb registers off.
331  */
332
333 static struct notifier_block wdt_notifier = {
334         .notifier_call = wdt_notify_sys,
335 };
336
337 static int __init wdt_init(void)
338 {
339         int ret;
340
341         printk(KERN_INFO "WDT driver for the Winbond(TM) W83697UG/UF Super I/O chip initialising.\n");
342
343         if (wdt_set_heartbeat(timeout)) {
344                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
345                 printk(KERN_INFO PFX
346                         "timeout value must be 1<=timeout<=255, using %d\n",
347                         WATCHDOG_TIMEOUT);
348         }
349
350         if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
351                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
352                         wdt_io);
353                 ret = -EIO;
354                 goto out;
355         }
356
357         ret = w83697ug_init();
358         if (ret != 0)
359                 goto unreg_regions;
360
361         ret = register_reboot_notifier(&wdt_notifier);
362         if (ret != 0) {
363                 printk(KERN_ERR PFX
364                         "cannot register reboot notifier (err=%d)\n", ret);
365                 goto unreg_regions;
366         }
367
368         ret = misc_register(&wdt_miscdev);
369         if (ret != 0) {
370                 printk(KERN_ERR PFX
371                         "cannot register miscdev on minor=%d (err=%d)\n",
372                         WATCHDOG_MINOR, ret);
373                 goto unreg_reboot;
374         }
375
376         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
377                 timeout, nowayout);
378
379 out:
380         return ret;
381 unreg_reboot:
382         unregister_reboot_notifier(&wdt_notifier);
383 unreg_regions:
384         release_region(wdt_io, 1);
385         goto out;
386 }
387
388 static void __exit wdt_exit(void)
389 {
390         misc_deregister(&wdt_miscdev);
391         unregister_reboot_notifier(&wdt_notifier);
392         release_region(wdt_io, 1);
393 }
394
395 module_init(wdt_init);
396 module_exit(wdt_exit);
397
398 MODULE_LICENSE("GPL");
399 MODULE_AUTHOR("Flemming Frandsen <ff@nrvissing.net>");
400 MODULE_DESCRIPTION("w83697ug/uf WDT driver");
401 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);