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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 *
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
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>
39#include <linux/notifier.h>
40#include <linux/fs.h>
41#include <linux/reboot.h>
42#include <linux/init.h>
43#include <linux/spinlock.h>
44#include <linux/moduleparam.h>
45
46#include <asm/io.h>
47#include <asm/uaccess.h>
48#include <asm/system.h>
49
50static unsigned long ibwdt_is_open;
51static spinlock_t ibwdt_lock;
52static char expect_close;
53
54#define PFX "ib700wdt: "
55
56/*
57 *
58 * Watchdog Timer Configuration
59 *
60 * The function of the watchdog timer is to reset the system
61 * automatically and is defined at I/O port 0443H. To enable the
62 * watchdog timer and allow the system to reset, write I/O port 0443H.
63 * To disable the timer, write I/O port 0441H for the system to stop the
64 * watchdog function. The timer has a tolerance of 20% for its
65 * intervals.
66 *
67 * The following describes how the timer should be programmed.
68 *
69 * Enabling Watchdog:
70 * MOV AX,000FH (Choose the values from 0 to F)
71 * MOV DX,0443H
72 * OUT DX,AX
73 *
74 * Disabling Watchdog:
75 * MOV AX,000FH (Any value is fine.)
76 * MOV DX,0441H
77 * OUT DX,AX
78 *
79 * Watchdog timer control table:
80 * Level Value Time/sec | Level Value Time/sec
81 * 1 F 0 | 9 7 16
82 * 2 E 2 | 10 6 18
83 * 3 D 4 | 11 5 20
84 * 4 C 6 | 12 4 22
85 * 5 B 8 | 13 3 24
86 * 6 A 10 | 14 2 26
87 * 7 9 12 | 15 1 28
88 * 8 8 14 | 16 0 30
89 *
90 */
91
92static int wd_times[] = {
93 30, /* 0x0 */
94 28, /* 0x1 */
95 26, /* 0x2 */
96 24, /* 0x3 */
97 22, /* 0x4 */
98 20, /* 0x5 */
99 18, /* 0x6 */
100 16, /* 0x7 */
101 14, /* 0x8 */
102 12, /* 0x9 */
103 10, /* 0xA */
104 8, /* 0xB */
105 6, /* 0xC */
106 4, /* 0xD */
107 2, /* 0xE */
108 0, /* 0xF */
109};
110
111#define WDT_STOP 0x441
112#define WDT_START 0x443
113
114/* Default timeout */
115#define WD_TIMO 0 /* 30 seconds +/- 20%, from table */
116
117static int wd_margin = WD_TIMO;
118
Andrey Panin4bfdf372005-07-27 11:43:58 -0700119static int nowayout = WATCHDOG_NOWAYOUT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120module_param(nowayout, int, 0);
121MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
122
123
124/*
125 * Kernel methods.
126 */
127
128static void
129ibwdt_ping(void)
130{
131 /* Write a watchdog value */
132 outb_p(wd_margin, WDT_START);
133}
134
135static ssize_t
136ibwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
137{
138 if (count) {
139 if (!nowayout) {
140 size_t i;
141
142 /* In case it was set long ago */
143 expect_close = 0;
144
145 for (i = 0; i != count; i++) {
146 char c;
147 if (get_user(c, buf + i))
148 return -EFAULT;
149 if (c == 'V')
150 expect_close = 42;
151 }
152 }
153 ibwdt_ping();
154 }
155 return count;
156}
157
158static int
159ibwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
160 unsigned long arg)
161{
162 int i, new_margin;
163 void __user *argp = (void __user *)arg;
164 int __user *p = argp;
165
166 static struct watchdog_info ident = {
167 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
168 .firmware_version = 1,
169 .identity = "IB700 WDT",
170 };
171
172 switch (cmd) {
173 case WDIOC_GETSUPPORT:
174 if (copy_to_user(argp, &ident, sizeof(ident)))
175 return -EFAULT;
176 break;
177
178 case WDIOC_GETSTATUS:
179 return put_user(0, p);
180
181 case WDIOC_KEEPALIVE:
182 ibwdt_ping();
183 break;
184
185 case WDIOC_SETTIMEOUT:
186 if (get_user(new_margin, p))
187 return -EFAULT;
188 if ((new_margin < 0) || (new_margin > 30))
189 return -EINVAL;
190 for (i = 0x0F; i > -1; i--)
191 if (wd_times[i] > new_margin)
192 break;
193 wd_margin = i;
194 ibwdt_ping();
195 /* Fall */
196
197 case WDIOC_GETTIMEOUT:
198 return put_user(wd_times[wd_margin], p);
199 break;
200
201 default:
Samuel Tardieu795b89d2006-09-09 17:34:31 +0200202 return -ENOTTY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 }
204 return 0;
205}
206
207static int
208ibwdt_open(struct inode *inode, struct file *file)
209{
210 spin_lock(&ibwdt_lock);
211 if (test_and_set_bit(0, &ibwdt_is_open)) {
212 spin_unlock(&ibwdt_lock);
213 return -EBUSY;
214 }
215 if (nowayout)
216 __module_get(THIS_MODULE);
217
218 /* Activate */
219 ibwdt_ping();
220 spin_unlock(&ibwdt_lock);
221 return nonseekable_open(inode, file);
222}
223
224static int
225ibwdt_close(struct inode *inode, struct file *file)
226{
227 spin_lock(&ibwdt_lock);
228 if (expect_close == 42)
229 outb_p(0, WDT_STOP);
230 else
231 printk(KERN_CRIT PFX "WDT device closed unexpectedly. WDT will not stop!\n");
232
233 clear_bit(0, &ibwdt_is_open);
234 expect_close = 0;
235 spin_unlock(&ibwdt_lock);
236 return 0;
237}
238
239/*
240 * Notifier for system down
241 */
242
243static int
244ibwdt_notify_sys(struct notifier_block *this, unsigned long code,
245 void *unused)
246{
247 if (code == SYS_DOWN || code == SYS_HALT) {
248 /* Turn the WDT off */
249 outb_p(0, WDT_STOP);
250 }
251 return NOTIFY_DONE;
252}
253
254/*
255 * Kernel Interfaces
256 */
257
Arjan van de Ven62322d22006-07-03 00:24:21 -0700258static const struct file_operations ibwdt_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 .owner = THIS_MODULE,
260 .llseek = no_llseek,
261 .write = ibwdt_write,
262 .ioctl = ibwdt_ioctl,
263 .open = ibwdt_open,
264 .release = ibwdt_close,
265};
266
267static struct miscdevice ibwdt_miscdev = {
268 .minor = WATCHDOG_MINOR,
269 .name = "watchdog",
270 .fops = &ibwdt_fops,
271};
272
273/*
274 * The WDT needs to learn about soft shutdowns in order to
275 * turn the timebomb registers off.
276 */
277
278static struct notifier_block ibwdt_notifier = {
279 .notifier_call = ibwdt_notify_sys,
280};
281
282static int __init ibwdt_init(void)
283{
284 int res;
285
286 printk(KERN_INFO PFX "WDT driver for IB700 single board computer initialising.\n");
287
288 spin_lock_init(&ibwdt_lock);
289 res = misc_register(&ibwdt_miscdev);
290 if (res) {
291 printk (KERN_ERR PFX "failed to register misc device\n");
292 goto out_nomisc;
293 }
294
295#if WDT_START != WDT_STOP
296 if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
297 printk (KERN_ERR PFX "STOP method I/O %X is not available.\n", WDT_STOP);
298 res = -EIO;
299 goto out_nostopreg;
300 }
301#endif
302
303 if (!request_region(WDT_START, 1, "IB700 WDT")) {
304 printk (KERN_ERR PFX "START method I/O %X is not available.\n", WDT_START);
305 res = -EIO;
306 goto out_nostartreg;
307 }
308 res = register_reboot_notifier(&ibwdt_notifier);
309 if (res) {
310 printk (KERN_ERR PFX "Failed to register reboot notifier.\n");
311 goto out_noreboot;
312 }
313 return 0;
314
315out_noreboot:
316 release_region(WDT_START, 1);
317out_nostartreg:
318#if WDT_START != WDT_STOP
319 release_region(WDT_STOP, 1);
320#endif
321out_nostopreg:
322 misc_deregister(&ibwdt_miscdev);
323out_nomisc:
324 return res;
325}
326
327static void __exit
328ibwdt_exit(void)
329{
330 misc_deregister(&ibwdt_miscdev);
331 unregister_reboot_notifier(&ibwdt_notifier);
332#if WDT_START != WDT_STOP
333 release_region(WDT_STOP,1);
334#endif
335 release_region(WDT_START,1);
336}
337
338module_init(ibwdt_init);
339module_exit(ibwdt_exit);
340
341MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
342MODULE_DESCRIPTION("IB700 SBC watchdog driver");
343MODULE_LICENSE("GPL");
344MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
345
346/* end of ib700wdt.c */