virtio_blk: use a wrapper function to access io context information of IO requests
[linux-3.10.git] / drivers / watchdog / ib700wdt.c
1 /*
2  *      IB700 Single Board Computer WDT driver
3  *
4  *      (c) Copyright 2001 Charles Howes <chowes@vsol.net>
5  *
6  *      Based on advantechwdt.c which is based on acquirewdt.c which
7  *      is based on wdt.c.
8  *
9  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
10  *
11  *      Based on acquirewdt.c which is based on wdt.c.
12  *      Original copyright messages:
13  *
14  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
15  *                              http://www.redhat.com
16  *
17  *      This program is free software; you can redistribute it and/or
18  *      modify it under the terms of the GNU General Public License
19  *      as published by the Free Software Foundation; either version
20  *      2 of the License, or (at your option) any later version.
21  *
22  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
23  *      warranty for any of this software. This material is provided
24  *      "AS-IS" and at no charge.
25  *
26  *      (c) Copyright 1995    Alan Cox <alan@redhat.com>
27  *
28  *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
29  *           Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
30  *           Added timeout module option to override default
31  *
32  */
33
34 #include <linux/module.h>
35 #include <linux/types.h>
36 #include <linux/miscdevice.h>
37 #include <linux/watchdog.h>
38 #include <linux/ioport.h>
39 #include <linux/fs.h>
40 #include <linux/init.h>
41 #include <linux/spinlock.h>
42 #include <linux/moduleparam.h>
43 #include <linux/platform_device.h>
44 #include <linux/io.h>
45 #include <linux/uaccess.h>
46
47 #include <asm/system.h>
48
49 static struct platform_device *ibwdt_platform_device;
50 static unsigned long ibwdt_is_open;
51 static DEFINE_SPINLOCK(ibwdt_lock);
52 static char expect_close;
53
54 /* Module information */
55 #define DRV_NAME "ib700wdt"
56 #define PFX DRV_NAME ": "
57
58 /*
59  *
60  * Watchdog Timer Configuration
61  *
62  * The function of the watchdog timer is to reset the system
63  * automatically and is defined at I/O port 0443H.  To enable the
64  * watchdog timer and allow the system to reset, write I/O port 0443H.
65  * To disable the timer, write I/O port 0441H for the system to stop the
66  * watchdog function.  The timer has a tolerance of 20% for its
67  * intervals.
68  *
69  * The following describes how the timer should be programmed.
70  *
71  * Enabling Watchdog:
72  * MOV AX,000FH (Choose the values from 0 to F)
73  * MOV DX,0443H
74  * OUT DX,AX
75  *
76  * Disabling Watchdog:
77  * MOV AX,000FH (Any value is fine.)
78  * MOV DX,0441H
79  * OUT DX,AX
80  *
81  * Watchdog timer control table:
82  * Level   Value  Time/sec | Level Value Time/sec
83  *   1       F       0     |   9     7      16
84  *   2       E       2     |   10    6      18
85  *   3       D       4     |   11    5      20
86  *   4       C       6     |   12    4      22
87  *   5       B       8     |   13    3      24
88  *   6       A       10    |   14    2      26
89  *   7       9       12    |   15    1      28
90  *   8       8       14    |   16    0      30
91  *
92  */
93
94 static int wd_times[] = {
95         30,     /* 0x0 */
96         28,     /* 0x1 */
97         26,     /* 0x2 */
98         24,     /* 0x3 */
99         22,     /* 0x4 */
100         20,     /* 0x5 */
101         18,     /* 0x6 */
102         16,     /* 0x7 */
103         14,     /* 0x8 */
104         12,     /* 0x9 */
105         10,     /* 0xA */
106         8,      /* 0xB */
107         6,      /* 0xC */
108         4,      /* 0xD */
109         2,      /* 0xE */
110         0,      /* 0xF */
111 };
112
113 #define WDT_STOP 0x441
114 #define WDT_START 0x443
115
116 /* Default timeout */
117 #define WD_TIMO 0               /* 30 seconds +/- 20%, from table */
118
119 static int wd_margin = WD_TIMO;
120
121 static int nowayout = WATCHDOG_NOWAYOUT;
122 module_param(nowayout, int, 0);
123 MODULE_PARM_DESC(nowayout,
124                 "Watchdog cannot be stopped once started (default="
125                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
126
127
128 /*
129  *      Watchdog Operations
130  */
131
132 static void ibwdt_ping(void)
133 {
134         spin_lock(&ibwdt_lock);
135
136         /* Write a watchdog value */
137         outb_p(wd_margin, WDT_START);
138
139         spin_unlock(&ibwdt_lock);
140 }
141
142 static void ibwdt_disable(void)
143 {
144         spin_lock(&ibwdt_lock);
145         outb_p(0, WDT_STOP);
146         spin_unlock(&ibwdt_lock);
147 }
148
149 static int ibwdt_set_heartbeat(int t)
150 {
151         int i;
152
153         if ((t < 0) || (t > 30))
154                 return -EINVAL;
155
156         for (i = 0x0F; i > -1; i--)
157                 if (wd_times[i] > t)
158                         break;
159         wd_margin = i;
160         return 0;
161 }
162
163 /*
164  *      /dev/watchdog handling
165  */
166
167 static ssize_t ibwdt_write(struct file *file, const char __user *buf,
168                                                 size_t count, loff_t *ppos)
169 {
170         if (count) {
171                 if (!nowayout) {
172                         size_t i;
173
174                         /* In case it was set long ago */
175                         expect_close = 0;
176
177                         for (i = 0; i != count; i++) {
178                                 char c;
179                                 if (get_user(c, buf + i))
180                                         return -EFAULT;
181                                 if (c == 'V')
182                                         expect_close = 42;
183                         }
184                 }
185                 ibwdt_ping();
186         }
187         return count;
188 }
189
190 static long ibwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
191 {
192         int new_margin;
193         void __user *argp = (void __user *)arg;
194         int __user *p = argp;
195
196         static struct watchdog_info ident = {
197                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
198                                                         | WDIOF_MAGICCLOSE,
199                 .firmware_version = 1,
200                 .identity = "IB700 WDT",
201         };
202
203         switch (cmd) {
204         case WDIOC_GETSUPPORT:
205                 if (copy_to_user(argp, &ident, sizeof(ident)))
206                         return -EFAULT;
207                 break;
208
209         case WDIOC_GETSTATUS:
210         case WDIOC_GETBOOTSTATUS:
211                 return put_user(0, p);
212
213         case WDIOC_SETOPTIONS:
214         {
215                 int options, retval = -EINVAL;
216
217                 if (get_user(options, p))
218                         return -EFAULT;
219
220                 if (options & WDIOS_DISABLECARD) {
221                         ibwdt_disable();
222                         retval = 0;
223                 }
224                 if (options & WDIOS_ENABLECARD) {
225                         ibwdt_ping();
226                         retval = 0;
227                 }
228                 return retval;
229         }
230         case WDIOC_KEEPALIVE:
231                 ibwdt_ping();
232                 break;
233
234         case WDIOC_SETTIMEOUT:
235                 if (get_user(new_margin, p))
236                         return -EFAULT;
237                 if (ibwdt_set_heartbeat(new_margin))
238                         return -EINVAL;
239                 ibwdt_ping();
240                 /* Fall */
241
242         case WDIOC_GETTIMEOUT:
243                 return put_user(wd_times[wd_margin], p);
244
245         default:
246                 return -ENOTTY;
247         }
248         return 0;
249 }
250
251 static int ibwdt_open(struct inode *inode, struct file *file)
252 {
253         if (test_and_set_bit(0, &ibwdt_is_open))
254                 return -EBUSY;
255         if (nowayout)
256                 __module_get(THIS_MODULE);
257
258         /* Activate */
259         ibwdt_ping();
260         return nonseekable_open(inode, file);
261 }
262
263 static int ibwdt_close(struct inode *inode, struct file *file)
264 {
265         if (expect_close == 42) {
266                 ibwdt_disable();
267         } else {
268                 printk(KERN_CRIT PFX
269                      "WDT device closed unexpectedly.  WDT will not stop!\n");
270                 ibwdt_ping();
271         }
272         clear_bit(0, &ibwdt_is_open);
273         expect_close = 0;
274         return 0;
275 }
276
277 /*
278  *      Kernel Interfaces
279  */
280
281 static const struct file_operations ibwdt_fops = {
282         .owner          = THIS_MODULE,
283         .llseek         = no_llseek,
284         .write          = ibwdt_write,
285         .unlocked_ioctl = ibwdt_ioctl,
286         .open           = ibwdt_open,
287         .release        = ibwdt_close,
288 };
289
290 static struct miscdevice ibwdt_miscdev = {
291         .minor = WATCHDOG_MINOR,
292         .name = "watchdog",
293         .fops = &ibwdt_fops,
294 };
295
296 /*
297  *      Init & exit routines
298  */
299
300 static int __devinit ibwdt_probe(struct platform_device *dev)
301 {
302         int res;
303
304 #if WDT_START != WDT_STOP
305         if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
306                 printk(KERN_ERR PFX "STOP method I/O %X is not available.\n",
307                                                                 WDT_STOP);
308                 res = -EIO;
309                 goto out_nostopreg;
310         }
311 #endif
312
313         if (!request_region(WDT_START, 1, "IB700 WDT")) {
314                 printk(KERN_ERR PFX "START method I/O %X is not available.\n",
315                                                                 WDT_START);
316                 res = -EIO;
317                 goto out_nostartreg;
318         }
319
320         res = misc_register(&ibwdt_miscdev);
321         if (res) {
322                 printk(KERN_ERR PFX "failed to register misc device\n");
323                 goto out_nomisc;
324         }
325         return 0;
326
327 out_nomisc:
328         release_region(WDT_START, 1);
329 out_nostartreg:
330 #if WDT_START != WDT_STOP
331         release_region(WDT_STOP, 1);
332 #endif
333 out_nostopreg:
334         return res;
335 }
336
337 static int __devexit ibwdt_remove(struct platform_device *dev)
338 {
339         misc_deregister(&ibwdt_miscdev);
340         release_region(WDT_START, 1);
341 #if WDT_START != WDT_STOP
342         release_region(WDT_STOP, 1);
343 #endif
344         return 0;
345 }
346
347 static void ibwdt_shutdown(struct platform_device *dev)
348 {
349         /* Turn the WDT off if we have a soft shutdown */
350         ibwdt_disable();
351 }
352
353 static struct platform_driver ibwdt_driver = {
354         .probe          = ibwdt_probe,
355         .remove         = __devexit_p(ibwdt_remove),
356         .shutdown       = ibwdt_shutdown,
357         .driver         = {
358                 .owner  = THIS_MODULE,
359                 .name   = DRV_NAME,
360         },
361 };
362
363 static int __init ibwdt_init(void)
364 {
365         int err;
366
367         printk(KERN_INFO PFX
368                 "WDT driver for IB700 single board computer initialising.\n");
369
370         err = platform_driver_register(&ibwdt_driver);
371         if (err)
372                 return err;
373
374         ibwdt_platform_device = platform_device_register_simple(DRV_NAME,
375                                                                 -1, NULL, 0);
376         if (IS_ERR(ibwdt_platform_device)) {
377                 err = PTR_ERR(ibwdt_platform_device);
378                 goto unreg_platform_driver;
379         }
380
381         return 0;
382
383 unreg_platform_driver:
384         platform_driver_unregister(&ibwdt_driver);
385         return err;
386 }
387
388 static void __exit ibwdt_exit(void)
389 {
390         platform_device_unregister(ibwdt_platform_device);
391         platform_driver_unregister(&ibwdt_driver);
392         printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
393 }
394
395 module_init(ibwdt_init);
396 module_exit(ibwdt_exit);
397
398 MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
399 MODULE_DESCRIPTION("IB700 SBC watchdog driver");
400 MODULE_LICENSE("GPL");
401 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
402
403 /* end of ib700wdt.c */