2 * SBC8360 Watchdog driver
4 * (c) Copyright 2005 Webcon, Inc.
6 * Based on ib700wdt.c, which is based on advantechwdt.c which is based
7 * on acquirewdt.c which is based on wdt.c.
9 * (c) Copyright 2001 Charles Howes <chowes@vsol.net>
11 * Based on advantechwdt.c which is based on acquirewdt.c which
14 * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
16 * Based on acquirewdt.c which is based on wdt.c.
17 * Original copyright messages:
19 * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
20 * http://www.redhat.com
22 * This program is free software; you can redistribute it and/or
23 * modify it under the terms of the GNU General Public License
24 * as published by the Free Software Foundation; either version
25 * 2 of the License, or (at your option) any later version.
27 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
28 * warranty for any of this software. This material is provided
29 * "AS-IS" and at no charge.
31 * (c) Copyright 1995 Alan Cox <alan@redhat.com>
33 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
34 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
35 * Added timeout module option to override default
39 #include <linux/config.h>
40 #include <linux/module.h>
41 #include <linux/types.h>
42 #include <linux/miscdevice.h>
43 #include <linux/watchdog.h>
44 #include <linux/ioport.h>
45 #include <linux/delay.h>
46 #include <linux/notifier.h>
48 #include <linux/reboot.h>
49 #include <linux/init.h>
50 #include <linux/spinlock.h>
51 #include <linux/moduleparam.h>
54 #include <asm/uaccess.h>
55 #include <asm/system.h>
57 static unsigned long sbc8360_is_open;
58 static spinlock_t sbc8360_lock;
59 static char expect_close;
61 #define PFX "sbc8360: "
65 * Watchdog Timer Configuration
67 * The function of the watchdog timer is to reset the system automatically
68 * and is defined at I/O port 0120H and 0121H. To enable the watchdog timer
69 * and allow the system to reset, write appropriate values from the table
70 * below to I/O port 0120H and 0121H. To disable the timer, write a zero
71 * value to I/O port 0121H for the system to stop the watchdog function.
73 * The following describes how the timer should be programmed (according to
74 * the vendor documentation)
77 * MOV AX,000AH (enable, phase I)
80 * MOV AX,000BH (enable, phase II)
83 * MOV AX,000nH (set multiplier n, from 1-4)
86 * MOV AX,000mH (set base timer m, from 0-F)
91 * MOV AX,000mH (same as set base timer, above)
96 * MOV AX,0000H (a zero value)
100 * Watchdog timeout configuration values:
103 * --|----------------------------------
104 * 0 | 0.5s 5s 50s 100s
105 * 1 | 1s 10s 100s 200s
106 * 2 | 1.5s 15s 150s 300s
107 * 3 | 2s 20s 200s 400s
108 * 4 | 2.5s 25s 250s 500s
109 * 5 | 3s 30s 300s 600s
110 * 6 | 3.5s 35s 350s 700s
111 * 7 | 4s 40s 400s 800s
112 * 8 | 4.5s 45s 450s 900s
113 * 9 | 5s 50s 500s 1000s
114 * A | 5.5s 55s 550s 1100s
115 * B | 6s 60s 600s 1200s
116 * C | 6.5s 65s 650s 1300s
117 * D | 7s 70s 700s 1400s
118 * E | 7.5s 75s 750s 1500s
119 * F | 8s 80s 800s 1600s
121 * Another way to say the same things is:
122 * For N=1, Timeout = (M+1) * 0.5s
123 * For N=2, Timeout = (M+1) * 5s
124 * For N=3, Timeout = (M+1) * 50s
125 * For N=4, Timeout = (M+1) * 100s
129 static int wd_times[64][2] = {
130 {0, 1}, /* 0 = 0.5s */
132 {2, 1}, /* 2 = 1.5s */
134 {4, 1}, /* 4 = 2.5s */
136 {6, 1}, /* 6 = 3.5s */
138 {8, 1}, /* 8 = 4.5s */
140 {0xA, 1}, /* 10 = 5.5s */
141 {0xB, 1}, /* 11 = 6s */
142 {0xC, 1}, /* 12 = 6.5s */
143 {0xD, 1}, /* 13 = 7s */
144 {0xE, 1}, /* 14 = 7.5s */
145 {0xF, 1}, /* 15 = 8s */
146 {0, 2}, /* 16 = 5s */
147 {1, 2}, /* 17 = 10s */
148 {2, 2}, /* 18 = 15s */
149 {3, 2}, /* 19 = 20s */
150 {4, 2}, /* 20 = 25s */
151 {5, 2}, /* 21 = 30s */
152 {6, 2}, /* 22 = 35s */
153 {7, 2}, /* 23 = 40s */
154 {8, 2}, /* 24 = 45s */
155 {9, 2}, /* 25 = 50s */
156 {0xA, 2}, /* 26 = 55s */
157 {0xB, 2}, /* 27 = 60s */
158 {0xC, 2}, /* 28 = 65s */
159 {0xD, 2}, /* 29 = 70s */
160 {0xE, 2}, /* 30 = 75s */
161 {0xF, 2}, /* 31 = 80s */
162 {0, 3}, /* 32 = 50s */
163 {1, 3}, /* 33 = 100s */
164 {2, 3}, /* 34 = 150s */
165 {3, 3}, /* 35 = 200s */
166 {4, 3}, /* 36 = 250s */
167 {5, 3}, /* 37 = 300s */
168 {6, 3}, /* 38 = 350s */
169 {7, 3}, /* 39 = 400s */
170 {8, 3}, /* 40 = 450s */
171 {9, 3}, /* 41 = 500s */
172 {0xA, 3}, /* 42 = 550s */
173 {0xB, 3}, /* 43 = 600s */
174 {0xC, 3}, /* 44 = 650s */
175 {0xD, 3}, /* 45 = 700s */
176 {0xE, 3}, /* 46 = 750s */
177 {0xF, 3}, /* 47 = 800s */
178 {0, 4}, /* 48 = 100s */
179 {1, 4}, /* 49 = 200s */
180 {2, 4}, /* 50 = 300s */
181 {3, 4}, /* 51 = 400s */
182 {4, 4}, /* 52 = 500s */
183 {5, 4}, /* 53 = 600s */
184 {6, 4}, /* 54 = 700s */
185 {7, 4}, /* 55 = 800s */
186 {8, 4}, /* 56 = 900s */
187 {9, 4}, /* 57 = 1000s */
188 {0xA, 4}, /* 58 = 1100s */
189 {0xB, 4}, /* 59 = 1200s */
190 {0xC, 4}, /* 60 = 1300s */
191 {0xD, 4}, /* 61 = 1400s */
192 {0xE, 4}, /* 62 = 1500s */
193 {0xF, 4} /* 63 = 1600s */
196 #define SBC8360_ENABLE 0x120
197 #define SBC8360_BASETIME 0x121
199 static int timeout = 27;
200 static int wd_margin = 0xB;
201 static int wd_multiplier = 2;
202 static int nowayout = WATCHDOG_NOWAYOUT;
204 module_param(timeout, int, 27);
205 MODULE_PARM_DESC(timeout, "Index into timeout table (0-63) (default=27 (60s))");
206 module_param(nowayout, int, 0);
207 MODULE_PARM_DESC(nowayout,
208 "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
214 /* Activate and pre-configure watchdog */
215 static void sbc8360_activate(void)
217 /* Enable the watchdog */
218 outb(0x0A, SBC8360_ENABLE);
219 msleep_interruptible(100);
220 outb(0x0B, SBC8360_ENABLE);
221 msleep_interruptible(100);
222 /* Set timeout multiplier */
223 outb(wd_multiplier, SBC8360_ENABLE);
224 msleep_interruptible(100);
225 /* Nothing happens until first sbc8360_ping() */
228 /* Kernel pings watchdog */
229 static void sbc8360_ping(void)
231 /* Write the base timer register */
232 outb(wd_margin, SBC8360_BASETIME);
235 /* Userspace pings kernel driver, or requests clean close */
236 static ssize_t sbc8360_write(struct file *file, const char __user * buf,
237 size_t count, loff_t * ppos)
243 /* In case it was set long ago */
246 for (i = 0; i != count; i++) {
248 if (get_user(c, buf + i))
259 static int sbc8360_open(struct inode *inode, struct file *file)
261 spin_lock(&sbc8360_lock);
262 if (test_and_set_bit(0, &sbc8360_is_open)) {
263 spin_unlock(&sbc8360_lock);
267 __module_get(THIS_MODULE);
269 /* Activate and ping once to start the countdown */
270 spin_unlock(&sbc8360_lock);
273 return nonseekable_open(inode, file);
276 static int sbc8360_close(struct inode *inode, struct file *file)
278 spin_lock(&sbc8360_lock);
279 if (expect_close == 42)
280 outb(0, SBC8360_ENABLE);
283 "SBC8360 device closed unexpectedly. SBC8360 will not stop!\n");
285 clear_bit(0, &sbc8360_is_open);
287 spin_unlock(&sbc8360_lock);
292 * Notifier for system down
295 static int sbc8360_notify_sys(struct notifier_block *this, unsigned long code,
298 if (code == SYS_DOWN || code == SYS_HALT) {
299 /* Disable the SBC8360 Watchdog */
300 outb(0, SBC8360_ENABLE);
309 static struct file_operations sbc8360_fops = {
310 .owner = THIS_MODULE,
312 .write = sbc8360_write,
313 .open = sbc8360_open,
314 .release = sbc8360_close,
317 static struct miscdevice sbc8360_miscdev = {
318 .minor = WATCHDOG_MINOR,
320 .fops = &sbc8360_fops,
324 * The SBC8360 needs to learn about soft shutdowns in order to
325 * turn the timebomb registers off.
328 static struct notifier_block sbc8360_notifier = {
329 .notifier_call = sbc8360_notify_sys,
332 static int __init sbc8360_init(void)
335 unsigned long int mseconds = 60000;
337 spin_lock_init(&sbc8360_lock);
338 res = misc_register(&sbc8360_miscdev);
340 printk(KERN_ERR PFX "failed to register misc device\n");
344 if (!request_region(SBC8360_ENABLE, 1, "SBC8360")) {
345 printk(KERN_ERR PFX "ENABLE method I/O %X is not available.\n",
348 goto out_noenablereg;
350 if (!request_region(SBC8360_BASETIME, 1, "SBC8360")) {
352 "BASETIME method I/O %X is not available.\n",
355 goto out_nobasetimereg;
358 res = register_reboot_notifier(&sbc8360_notifier);
360 printk(KERN_ERR PFX "Failed to register reboot notifier.\n");
364 if (timeout < 0 || timeout > 63) {
365 printk(KERN_ERR PFX "Invalid timeout index (must be 0-63).\n");
370 wd_margin = wd_times[timeout][0];
371 wd_multiplier = wd_times[timeout][1];
373 if (wd_multiplier == 1)
374 mseconds = (wd_margin + 1) * 500;
375 else if (wd_multiplier == 2)
376 mseconds = (wd_margin + 1) * 5000;
377 else if (wd_multiplier == 3)
378 mseconds = (wd_margin + 1) * 50000;
379 else if (wd_multiplier == 4)
380 mseconds = (wd_margin + 1) * 100000;
382 /* My kingdom for the ability to print "0.5 seconds" in the kernel! */
383 printk(KERN_INFO PFX "Timeout set at %ld ms.\n", mseconds);
388 release_region(SBC8360_ENABLE, 1);
389 release_region(SBC8360_BASETIME, 1);
392 misc_deregister(&sbc8360_miscdev);
397 static void __exit sbc8360_exit(void)
399 misc_deregister(&sbc8360_miscdev);
400 unregister_reboot_notifier(&sbc8360_notifier);
401 release_region(SBC8360_ENABLE, 1);
402 release_region(SBC8360_BASETIME, 1);
405 module_init(sbc8360_init);
406 module_exit(sbc8360_exit);
408 MODULE_AUTHOR("Ian E. Morgan <imorgan@webcon.ca>");
409 MODULE_DESCRIPTION("SBC8360 watchdog driver");
410 MODULE_LICENSE("GPL");
411 MODULE_VERSION("1.0");
412 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
414 /* end of sbc8360.c */