[WATCHDOG] sbc8360.c - move stop code into a function
[deliverable/linux.git] / drivers / watchdog / ib700wdt.c
CommitLineData
1da177e4
LT
1/*
2 * IB700 Single Board Computer WDT driver
3 *
4 * (c) Copyright 2001 Charles Howes <chowes@vsol.net>
5 *
c9d7710e
WVS
6 * Based on advantechwdt.c which is based on acquirewdt.c which
7 * is based on wdt.c.
1da177e4
LT
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 *
c9d7710e
WVS
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
1da177e4
LT
31 *
32 */
33
1da177e4
LT
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>
1da177e4 39#include <linux/fs.h>
1da177e4
LT
40#include <linux/init.h>
41#include <linux/spinlock.h>
42#include <linux/moduleparam.h>
745ac1ea 43#include <linux/platform_device.h>
2e43ba73
AC
44#include <linux/io.h>
45#include <linux/uaccess.h>
089ab079 46
1da177e4
LT
47#include <asm/system.h>
48
745ac1ea 49static struct platform_device *ibwdt_platform_device;
1da177e4 50static unsigned long ibwdt_is_open;
c7dfd0cc 51static DEFINE_SPINLOCK(ibwdt_lock);
1da177e4
LT
52static char expect_close;
53
745ac1ea
WVS
54/* Module information */
55#define DRV_NAME "ib700wdt"
56#define PFX DRV_NAME ": "
1da177e4
LT
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
94static 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
119static int wd_margin = WD_TIMO;
120
4bfdf378 121static int nowayout = WATCHDOG_NOWAYOUT;
1da177e4 122module_param(nowayout, int, 0);
2e43ba73
AC
123MODULE_PARM_DESC(nowayout,
124 "Watchdog cannot be stopped once started (default="
125 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
1da177e4
LT
126
127
128/*
35d55c94 129 * Watchdog Operations
1da177e4
LT
130 */
131
132static void
133ibwdt_ping(void)
134{
e42162a4
WVS
135 spin_lock(&ibwdt_lock);
136
1da177e4
LT
137 /* Write a watchdog value */
138 outb_p(wd_margin, WDT_START);
e42162a4
WVS
139
140 spin_unlock(&ibwdt_lock);
1da177e4
LT
141}
142
35d55c94
WVS
143static void
144ibwdt_disable(void)
145{
e42162a4 146 spin_lock(&ibwdt_lock);
35d55c94 147 outb_p(0, WDT_STOP);
e42162a4 148 spin_unlock(&ibwdt_lock);
35d55c94
WVS
149}
150
151static int
152ibwdt_set_heartbeat(int t)
153{
154 int i;
155
156 if ((t < 0) || (t > 30))
157 return -EINVAL;
158
159 for (i = 0x0F; i > -1; i--)
160 if (wd_times[i] > t)
161 break;
162 wd_margin = i;
163 return 0;
164}
165
166/*
167 * /dev/watchdog handling
168 */
169
2e43ba73
AC
170static ssize_t ibwdt_write(struct file *file, const char __user *buf,
171 size_t count, loff_t *ppos)
1da177e4
LT
172{
173 if (count) {
174 if (!nowayout) {
175 size_t i;
176
177 /* In case it was set long ago */
178 expect_close = 0;
179
180 for (i = 0; i != count; i++) {
181 char c;
182 if (get_user(c, buf + i))
183 return -EFAULT;
184 if (c == 'V')
185 expect_close = 42;
186 }
187 }
188 ibwdt_ping();
189 }
190 return count;
191}
192
2e43ba73 193static long ibwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1da177e4 194{
35d55c94 195 int new_margin;
1da177e4
LT
196 void __user *argp = (void __user *)arg;
197 int __user *p = argp;
198
199 static struct watchdog_info ident = {
2e43ba73
AC
200 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
201 | WDIOF_MAGICCLOSE,
1da177e4
LT
202 .firmware_version = 1,
203 .identity = "IB700 WDT",
204 };
205
206 switch (cmd) {
207 case WDIOC_GETSUPPORT:
2e43ba73
AC
208 if (copy_to_user(argp, &ident, sizeof(ident)))
209 return -EFAULT;
210 break;
1da177e4
LT
211
212 case WDIOC_GETSTATUS:
c9d7710e 213 case WDIOC_GETBOOTSTATUS:
2e43ba73 214 return put_user(0, p);
1da177e4 215
e42162a4
WVS
216 case WDIOC_SETOPTIONS:
217 {
2e43ba73 218 int options, retval = -EINVAL;
e42162a4 219
2e43ba73
AC
220 if (get_user(options, p))
221 return -EFAULT;
e42162a4 222
2e43ba73
AC
223 if (options & WDIOS_DISABLECARD) {
224 ibwdt_disable();
225 retval = 0;
226 }
227 if (options & WDIOS_ENABLECARD) {
228 ibwdt_ping();
229 retval = 0;
230 }
231 return retval;
e42162a4 232 }
0c06090c
WVS
233 case WDIOC_KEEPALIVE:
234 ibwdt_ping();
235 break;
236
237 case WDIOC_SETTIMEOUT:
238 if (get_user(new_margin, p))
239 return -EFAULT;
240 if (ibwdt_set_heartbeat(new_margin))
241 return -EINVAL;
242 ibwdt_ping();
243 /* Fall */
244
245 case WDIOC_GETTIMEOUT:
246 return put_user(wd_times[wd_margin], p);
247
1da177e4 248 default:
2e43ba73 249 return -ENOTTY;
1da177e4
LT
250 }
251 return 0;
252}
253
2e43ba73 254static int ibwdt_open(struct inode *inode, struct file *file)
1da177e4 255{
2e43ba73 256 if (test_and_set_bit(0, &ibwdt_is_open))
1da177e4 257 return -EBUSY;
1da177e4
LT
258 if (nowayout)
259 __module_get(THIS_MODULE);
260
261 /* Activate */
262 ibwdt_ping();
1da177e4
LT
263 return nonseekable_open(inode, file);
264}
265
266static int
267ibwdt_close(struct inode *inode, struct file *file)
268{
c9d7710e 269 if (expect_close == 42) {
35d55c94 270 ibwdt_disable();
c9d7710e 271 } else {
2e43ba73
AC
272 printk(KERN_CRIT PFX
273 "WDT device closed unexpectedly. WDT will not stop!\n");
c9d7710e
WVS
274 ibwdt_ping();
275 }
1da177e4
LT
276 clear_bit(0, &ibwdt_is_open);
277 expect_close = 0;
1da177e4
LT
278 return 0;
279}
280
1da177e4
LT
281/*
282 * Kernel Interfaces
283 */
284
62322d25 285static const struct file_operations ibwdt_fops = {
1da177e4
LT
286 .owner = THIS_MODULE,
287 .llseek = no_llseek,
288 .write = ibwdt_write,
2e43ba73 289 .unlocked_ioctl = ibwdt_ioctl,
1da177e4
LT
290 .open = ibwdt_open,
291 .release = ibwdt_close,
292};
293
294static struct miscdevice ibwdt_miscdev = {
295 .minor = WATCHDOG_MINOR,
296 .name = "watchdog",
297 .fops = &ibwdt_fops,
298};
299
f6e48039
WVS
300/*
301 * Init & exit routines
302 */
303
745ac1ea 304static int __devinit ibwdt_probe(struct platform_device *dev)
1da177e4
LT
305{
306 int res;
307
1da177e4
LT
308#if WDT_START != WDT_STOP
309 if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
2e43ba73
AC
310 printk(KERN_ERR PFX "STOP method I/O %X is not available.\n",
311 WDT_STOP);
1da177e4
LT
312 res = -EIO;
313 goto out_nostopreg;
314 }
315#endif
316
317 if (!request_region(WDT_START, 1, "IB700 WDT")) {
2e43ba73
AC
318 printk(KERN_ERR PFX "START method I/O %X is not available.\n",
319 WDT_START);
1da177e4
LT
320 res = -EIO;
321 goto out_nostartreg;
322 }
f6e48039 323
f6e48039
WVS
324 res = misc_register(&ibwdt_miscdev);
325 if (res) {
2e43ba73 326 printk(KERN_ERR PFX "failed to register misc device\n");
f6e48039
WVS
327 goto out_nomisc;
328 }
1da177e4
LT
329 return 0;
330
f6e48039 331out_nomisc:
1da177e4
LT
332 release_region(WDT_START, 1);
333out_nostartreg:
334#if WDT_START != WDT_STOP
335 release_region(WDT_STOP, 1);
336#endif
337out_nostopreg:
1da177e4
LT
338 return res;
339}
340
745ac1ea 341static int __devexit ibwdt_remove(struct platform_device *dev)
1da177e4
LT
342{
343 misc_deregister(&ibwdt_miscdev);
2e43ba73 344 release_region(WDT_START, 1);
1da177e4 345#if WDT_START != WDT_STOP
2e43ba73 346 release_region(WDT_STOP, 1);
1da177e4 347#endif
745ac1ea
WVS
348 return 0;
349}
350
35fcf538
WVS
351static void ibwdt_shutdown(struct platform_device *dev)
352{
353 /* Turn the WDT off if we have a soft shutdown */
354 ibwdt_disable();
355}
356
745ac1ea
WVS
357static struct platform_driver ibwdt_driver = {
358 .probe = ibwdt_probe,
359 .remove = __devexit_p(ibwdt_remove),
35fcf538 360 .shutdown = ibwdt_shutdown,
745ac1ea
WVS
361 .driver = {
362 .owner = THIS_MODULE,
363 .name = DRV_NAME,
364 },
365};
366
367static int __init ibwdt_init(void)
368{
369 int err;
370
2e43ba73
AC
371 printk(KERN_INFO PFX
372 "WDT driver for IB700 single board computer initialising.\n");
745ac1ea
WVS
373
374 err = platform_driver_register(&ibwdt_driver);
375 if (err)
376 return err;
377
2e43ba73
AC
378 ibwdt_platform_device = platform_device_register_simple(DRV_NAME,
379 -1, NULL, 0);
745ac1ea
WVS
380 if (IS_ERR(ibwdt_platform_device)) {
381 err = PTR_ERR(ibwdt_platform_device);
382 goto unreg_platform_driver;
383 }
384
385 return 0;
386
387unreg_platform_driver:
388 platform_driver_unregister(&ibwdt_driver);
389 return err;
390}
391
392static void __exit ibwdt_exit(void)
393{
394 platform_device_unregister(ibwdt_platform_device);
395 platform_driver_unregister(&ibwdt_driver);
396 printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
1da177e4
LT
397}
398
399module_init(ibwdt_init);
400module_exit(ibwdt_exit);
401
402MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
403MODULE_DESCRIPTION("IB700 SBC watchdog driver");
404MODULE_LICENSE("GPL");
405MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
406
407/* end of ib700wdt.c */
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