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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * IB700 Single Board Computer WDT driver
3 *
4 * (c) Copyright 2001 Charles Howes <chowes@vsol.net>
5 *
Wim Van Sebroeckc9d77102007-01-27 22:07:03 +01006 * Based on advantechwdt.c which is based on acquirewdt.c which
7 * is based on wdt.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 *
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 *
Wim Van Sebroeckc9d77102007-01-27 22:07:03 +010028 * 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070031 *
32 */
33
Linus Torvalds1da177e2005-04-16 15:20:36 -070034#include <linux/module.h>
35#include <linux/types.h>
36#include <linux/miscdevice.h>
37#include <linux/watchdog.h>
38#include <linux/ioport.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070039#include <linux/fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070040#include <linux/init.h>
41#include <linux/spinlock.h>
42#include <linux/moduleparam.h>
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +010043#include <linux/platform_device.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070044
45#include <asm/io.h>
46#include <asm/uaccess.h>
47#include <asm/system.h>
48
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +010049static struct platform_device *ibwdt_platform_device;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050static unsigned long ibwdt_is_open;
Alexey Dobriyanc7dfd0c2007-11-01 16:27:08 -070051static DEFINE_SPINLOCK(ibwdt_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070052static char expect_close;
53
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +010054/* Module information */
55#define DRV_NAME "ib700wdt"
56#define PFX DRV_NAME ": "
Linus Torvalds1da177e2005-04-16 15:20:36 -070057
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
Andrey Panin4bfdf372005-07-27 11:43:58 -0700121static int nowayout = WATCHDOG_NOWAYOUT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122module_param(nowayout, int, 0);
Wim Van Sebroeckbffda5c2007-01-27 20:54:24 +0100123MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124
125
126/*
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100127 * Watchdog Operations
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 */
129
130static void
131ibwdt_ping(void)
132{
Wim Van Sebroecke42162a2007-01-27 22:12:54 +0100133 spin_lock(&ibwdt_lock);
134
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 /* Write a watchdog value */
136 outb_p(wd_margin, WDT_START);
Wim Van Sebroecke42162a2007-01-27 22:12:54 +0100137
138 spin_unlock(&ibwdt_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139}
140
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100141static void
142ibwdt_disable(void)
143{
Wim Van Sebroecke42162a2007-01-27 22:12:54 +0100144 spin_lock(&ibwdt_lock);
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100145 outb_p(0, WDT_STOP);
Wim Van Sebroecke42162a2007-01-27 22:12:54 +0100146 spin_unlock(&ibwdt_lock);
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100147}
148
149static int
150ibwdt_set_heartbeat(int t)
151{
152 int i;
153
154 if ((t < 0) || (t > 30))
155 return -EINVAL;
156
157 for (i = 0x0F; i > -1; i--)
158 if (wd_times[i] > t)
159 break;
160 wd_margin = i;
161 return 0;
162}
163
164/*
165 * /dev/watchdog handling
166 */
167
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168static ssize_t
169ibwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
170{
171 if (count) {
172 if (!nowayout) {
173 size_t i;
174
175 /* In case it was set long ago */
176 expect_close = 0;
177
178 for (i = 0; i != count; i++) {
179 char c;
180 if (get_user(c, buf + i))
181 return -EFAULT;
182 if (c == 'V')
183 expect_close = 42;
184 }
185 }
186 ibwdt_ping();
187 }
188 return count;
189}
190
191static int
192ibwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
193 unsigned long arg)
194{
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100195 int new_margin;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 void __user *argp = (void __user *)arg;
197 int __user *p = argp;
198
199 static struct watchdog_info ident = {
200 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
201 .firmware_version = 1,
202 .identity = "IB700 WDT",
203 };
204
205 switch (cmd) {
206 case WDIOC_GETSUPPORT:
207 if (copy_to_user(argp, &ident, sizeof(ident)))
208 return -EFAULT;
209 break;
210
211 case WDIOC_GETSTATUS:
Wim Van Sebroeckc9d77102007-01-27 22:07:03 +0100212 case WDIOC_GETBOOTSTATUS:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 return put_user(0, p);
214
215 case WDIOC_KEEPALIVE:
216 ibwdt_ping();
217 break;
218
219 case WDIOC_SETTIMEOUT:
220 if (get_user(new_margin, p))
221 return -EFAULT;
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100222 if (ibwdt_set_heartbeat(new_margin))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 ibwdt_ping();
225 /* Fall */
226
227 case WDIOC_GETTIMEOUT:
228 return put_user(wd_times[wd_margin], p);
Wim Van Sebroecke42162a2007-01-27 22:12:54 +0100229
230 case WDIOC_SETOPTIONS:
231 {
232 int options, retval = -EINVAL;
233
234 if (get_user(options, p))
235 return -EFAULT;
236
237 if (options & WDIOS_DISABLECARD) {
238 ibwdt_disable();
239 retval = 0;
240 }
241
242 if (options & WDIOS_ENABLECARD) {
243 ibwdt_ping();
244 retval = 0;
245 }
246
247 return retval;
248 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249
250 default:
Samuel Tardieu795b89d2006-09-09 17:34:31 +0200251 return -ENOTTY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 }
253 return 0;
254}
255
256static int
257ibwdt_open(struct inode *inode, struct file *file)
258{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 if (test_and_set_bit(0, &ibwdt_is_open)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 return -EBUSY;
261 }
262 if (nowayout)
263 __module_get(THIS_MODULE);
264
265 /* Activate */
266 ibwdt_ping();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 return nonseekable_open(inode, file);
268}
269
270static int
271ibwdt_close(struct inode *inode, struct file *file)
272{
Wim Van Sebroeckc9d77102007-01-27 22:07:03 +0100273 if (expect_close == 42) {
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100274 ibwdt_disable();
Wim Van Sebroeckc9d77102007-01-27 22:07:03 +0100275 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 printk(KERN_CRIT PFX "WDT device closed unexpectedly. WDT will not stop!\n");
Wim Van Sebroeckc9d77102007-01-27 22:07:03 +0100277 ibwdt_ping();
278 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 clear_bit(0, &ibwdt_is_open);
280 expect_close = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 return 0;
282}
283
284/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 * Kernel Interfaces
286 */
287
Arjan van de Ven62322d22006-07-03 00:24:21 -0700288static const struct file_operations ibwdt_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 .owner = THIS_MODULE,
290 .llseek = no_llseek,
291 .write = ibwdt_write,
292 .ioctl = ibwdt_ioctl,
293 .open = ibwdt_open,
294 .release = ibwdt_close,
295};
296
297static struct miscdevice ibwdt_miscdev = {
298 .minor = WATCHDOG_MINOR,
299 .name = "watchdog",
300 .fops = &ibwdt_fops,
301};
302
303/*
Wim Van Sebroeckf6e48032007-01-27 21:58:08 +0100304 * Init & exit routines
305 */
306
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +0100307static int __devinit ibwdt_probe(struct platform_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308{
309 int res;
310
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311#if WDT_START != WDT_STOP
312 if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
313 printk (KERN_ERR PFX "STOP method I/O %X is not available.\n", WDT_STOP);
314 res = -EIO;
315 goto out_nostopreg;
316 }
317#endif
318
319 if (!request_region(WDT_START, 1, "IB700 WDT")) {
320 printk (KERN_ERR PFX "START method I/O %X is not available.\n", WDT_START);
321 res = -EIO;
322 goto out_nostartreg;
323 }
Wim Van Sebroeckf6e48032007-01-27 21:58:08 +0100324
Wim Van Sebroeckf6e48032007-01-27 21:58:08 +0100325 res = misc_register(&ibwdt_miscdev);
326 if (res) {
327 printk (KERN_ERR PFX "failed to register misc device\n");
328 goto out_nomisc;
329 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 return 0;
331
Wim Van Sebroeckf6e48032007-01-27 21:58:08 +0100332out_nomisc:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 release_region(WDT_START, 1);
334out_nostartreg:
335#if WDT_START != WDT_STOP
336 release_region(WDT_STOP, 1);
337#endif
338out_nostopreg:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 return res;
340}
341
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +0100342static int __devexit ibwdt_remove(struct platform_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343{
344 misc_deregister(&ibwdt_miscdev);
Wim Van Sebroeckf6e48032007-01-27 21:58:08 +0100345 release_region(WDT_START,1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346#if WDT_START != WDT_STOP
347 release_region(WDT_STOP,1);
348#endif
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +0100349 return 0;
350}
351
Wim Van Sebroeck35fcf532007-01-27 22:54:18 +0100352static void ibwdt_shutdown(struct platform_device *dev)
353{
354 /* Turn the WDT off if we have a soft shutdown */
355 ibwdt_disable();
356}
357
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +0100358static struct platform_driver ibwdt_driver = {
359 .probe = ibwdt_probe,
360 .remove = __devexit_p(ibwdt_remove),
Wim Van Sebroeck35fcf532007-01-27 22:54:18 +0100361 .shutdown = ibwdt_shutdown,
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +0100362 .driver = {
363 .owner = THIS_MODULE,
364 .name = DRV_NAME,
365 },
366};
367
368static int __init ibwdt_init(void)
369{
370 int err;
371
372 printk(KERN_INFO PFX "WDT driver for IB700 single board computer initialising.\n");
373
374 err = platform_driver_register(&ibwdt_driver);
375 if (err)
376 return err;
377
378 ibwdt_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0);
379 if (IS_ERR(ibwdt_platform_device)) {
380 err = PTR_ERR(ibwdt_platform_device);
381 goto unreg_platform_driver;
382 }
383
384 return 0;
385
386unreg_platform_driver:
387 platform_driver_unregister(&ibwdt_driver);
388 return err;
389}
390
391static void __exit ibwdt_exit(void)
392{
393 platform_device_unregister(ibwdt_platform_device);
394 platform_driver_unregister(&ibwdt_driver);
395 printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396}
397
398module_init(ibwdt_init);
399module_exit(ibwdt_exit);
400
401MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
402MODULE_DESCRIPTION("IB700 SBC watchdog driver");
403MODULE_LICENSE("GPL");
404MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
405
406/* end of ib700wdt.c */