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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Acquire Single Board Computer Watchdog Timer driver
3 *
Wim Van Sebroeck143a2e52009-03-18 08:35:09 +00004 * Based on wdt.c. Original copyright messages:
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 *
Alan Cox29fa0582008-10-27 15:17:56 +00006 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
7 * All Rights Reserved.
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
13 *
14 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
15 * warranty for any of this software. This material is provided
16 * "AS-IS" and at no charge.
17 *
Alan Cox29fa0582008-10-27 15:17:56 +000018 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019 *
Wim Van Sebroeck143a2e52009-03-18 08:35:09 +000020 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
21 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
22 * Can't add timeout - driver doesn't allow changing value
Linus Torvalds1da177e2005-04-16 15:20:36 -070023 */
24
25/*
26 * Theory of Operation:
27 * The Watch-Dog Timer is provided to ensure that standalone
28 * Systems can always recover from catastrophic conditions that
Lucas De Marchi25985ed2011-03-30 22:57:33 -030029 * caused the CPU to crash. This condition may have occurred by
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 * external EMI or a software bug. When the CPU stops working
31 * correctly, hardware on the board will either perform a hardware
32 * reset (cold boot) or a non-maskable interrupt (NMI) to bring the
33 * system back to a known state.
34 *
35 * The Watch-Dog Timer is controlled by two I/O Ports.
36 * 443 hex - Read - Enable or refresh the Watch-Dog Timer
37 * 043 hex - Read - Disable the Watch-Dog Timer
38 *
39 * To enable the Watch-Dog Timer, a read from I/O port 443h must
40 * be performed. This will enable and activate the countdown timer
41 * which will eventually time out and either reset the CPU or cause
42 * an NMI depending on the setting of a jumper. To ensure that this
43 * reset condition does not occur, the Watch-Dog Timer must be
44 * periodically refreshed by reading the same I/O port 443h.
45 * The Watch-Dog Timer is disabled by reading I/O port 043h.
46 *
47 * The Watch-Dog Timer Time-Out Period is set via jumpers.
48 * It can be 1, 2, 10, 20, 110 or 220 seconds.
49 */
50
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +010051/*
52 * Includes, defines, variables, module parameters, ...
53 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070054
Joe Perches27c766a2012-02-15 15:06:19 -080055#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
56
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +010057/* Includes */
58#include <linux/module.h> /* For module specific items */
59#include <linux/moduleparam.h> /* For new moduleparam's */
60#include <linux/types.h> /* For standard types (like size_t) */
61#include <linux/errno.h> /* For the -ENODEV/... values */
62#include <linux/kernel.h> /* For printk/panic/... */
Alan Cox94da1e22008-05-19 14:04:46 +010063#include <linux/miscdevice.h> /* For MODULE_ALIAS_MISCDEV
64 (WATCHDOG_MINOR) */
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +010065#include <linux/watchdog.h> /* For the watchdog specific items */
66#include <linux/fs.h> /* For file operations */
67#include <linux/ioport.h> /* For io-port access */
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +010068#include <linux/platform_device.h> /* For platform_driver framework */
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +010069#include <linux/init.h> /* For __init/__exit/... */
Alan Cox94da1e22008-05-19 14:04:46 +010070#include <linux/uaccess.h> /* For copy_to_user/put_user/... */
71#include <linux/io.h> /* For inb/outb/... */
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +010072
73/* Module information */
74#define DRV_NAME "acquirewdt"
Linus Torvalds1da177e2005-04-16 15:20:36 -070075#define WATCHDOG_NAME "Acquire WDT"
Alan Cox94da1e22008-05-19 14:04:46 +010076/* There is no way to see what the correct time-out period is */
77#define WATCHDOG_HEARTBEAT 0
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +010079/* internal variables */
Alan Cox94da1e22008-05-19 14:04:46 +010080/* the watchdog platform device */
81static struct platform_device *acq_platform_device;
Linus Torvalds1da177e2005-04-16 15:20:36 -070082static unsigned long acq_is_open;
83static char expect_close;
84
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +010085/* module parameters */
Alan Cox94da1e22008-05-19 14:04:46 +010086/* You must set this - there is no sane way to probe for this board. */
87static int wdt_stop = 0x43;
Linus Torvalds1da177e2005-04-16 15:20:36 -070088module_param(wdt_stop, int, 0);
89MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)");
90
Alan Cox94da1e22008-05-19 14:04:46 +010091/* You must set this - there is no sane way to probe for this board. */
92static int wdt_start = 0x443;
Linus Torvalds1da177e2005-04-16 15:20:36 -070093module_param(wdt_start, int, 0);
94MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)");
95
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010096static bool nowayout = WATCHDOG_NOWAYOUT;
97module_param(nowayout, bool, 0);
Alan Cox94da1e22008-05-19 14:04:46 +010098MODULE_PARM_DESC(nowayout,
99 "Watchdog cannot be stopped once started (default="
100 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101
102/*
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +0100103 * Watchdog Operations
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 */
105
106static void acq_keepalive(void)
107{
108 /* Write a watchdog value */
109 inb_p(wdt_start);
110}
111
112static void acq_stop(void)
113{
114 /* Turn the card off */
115 inb_p(wdt_stop);
116}
117
118/*
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +0100119 * /dev/watchdog handling
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 */
121
Alan Cox94da1e22008-05-19 14:04:46 +0100122static ssize_t acq_write(struct file *file, const char __user *buf,
123 size_t count, loff_t *ppos)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124{
125 /* See if we got the magic character 'V' and reload the timer */
Alan Cox94da1e22008-05-19 14:04:46 +0100126 if (count) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 if (!nowayout) {
128 size_t i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 /* note: just in case someone wrote the magic character
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000130 five months ago... */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 expect_close = 0;
Alan Cox94da1e22008-05-19 14:04:46 +0100132 /* scan to see whether or not we got the
133 magic character */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 for (i = 0; i != count; i++) {
135 char c;
136 if (get_user(c, buf + i))
137 return -EFAULT;
138 if (c == 'V')
139 expect_close = 42;
140 }
141 }
Alan Cox94da1e22008-05-19 14:04:46 +0100142 /* Well, anyhow someone wrote to us, we should
143 return that favour */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 acq_keepalive();
145 }
146 return count;
147}
148
Alan Cox94da1e22008-05-19 14:04:46 +0100149static long acq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150{
151 int options, retval = -EINVAL;
152 void __user *argp = (void __user *)arg;
153 int __user *p = argp;
Wim Van Sebroeck42747d72009-12-26 18:55:22 +0000154 static const struct watchdog_info ident = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
156 .firmware_version = 1,
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +0100157 .identity = WATCHDOG_NAME,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158 };
159
Alan Cox94da1e22008-05-19 14:04:46 +0100160 switch (cmd) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 case WDIOC_GETSUPPORT:
Alan Cox94da1e22008-05-19 14:04:46 +0100162 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163
164 case WDIOC_GETSTATUS:
165 case WDIOC_GETBOOTSTATUS:
Alan Cox94da1e22008-05-19 14:04:46 +0100166 return put_user(0, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 case WDIOC_SETOPTIONS:
169 {
Alan Cox94da1e22008-05-19 14:04:46 +0100170 if (get_user(options, p))
171 return -EFAULT;
172 if (options & WDIOS_DISABLECARD) {
173 acq_stop();
174 retval = 0;
175 }
176 if (options & WDIOS_ENABLECARD) {
177 acq_keepalive();
178 retval = 0;
179 }
180 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 }
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000182 case WDIOC_KEEPALIVE:
183 acq_keepalive();
184 return 0;
185
186 case WDIOC_GETTIMEOUT:
187 return put_user(WATCHDOG_HEARTBEAT, p);
188
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 default:
Alan Cox94da1e22008-05-19 14:04:46 +0100190 return -ENOTTY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 }
192}
193
194static int acq_open(struct inode *inode, struct file *file)
195{
196 if (test_and_set_bit(0, &acq_is_open))
197 return -EBUSY;
198
199 if (nowayout)
200 __module_get(THIS_MODULE);
201
202 /* Activate */
203 acq_keepalive();
204 return nonseekable_open(inode, file);
205}
206
207static int acq_close(struct inode *inode, struct file *file)
208{
209 if (expect_close == 42) {
210 acq_stop();
211 } else {
Joe Perches27c766a2012-02-15 15:06:19 -0800212 pr_crit("Unexpected close, not stopping watchdog!\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 acq_keepalive();
214 }
215 clear_bit(0, &acq_is_open);
216 expect_close = 0;
217 return 0;
218}
219
220/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 * Kernel Interfaces
222 */
223
Arjan van de Ven62322d22006-07-03 00:24:21 -0700224static const struct file_operations acq_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 .owner = THIS_MODULE,
226 .llseek = no_llseek,
227 .write = acq_write,
Alan Cox94da1e22008-05-19 14:04:46 +0100228 .unlocked_ioctl = acq_ioctl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 .open = acq_open,
230 .release = acq_close,
231};
232
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +0100233static struct miscdevice acq_miscdev = {
234 .minor = WATCHDOG_MINOR,
235 .name = "watchdog",
236 .fops = &acq_fops,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237};
238
239/*
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +0100240 * Init & exit routines
241 */
242
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +0100243static int __devinit acq_probe(struct platform_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244{
245 int ret;
246
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 if (wdt_stop != wdt_start) {
248 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
Joe Perches27c766a2012-02-15 15:06:19 -0800249 pr_err("I/O address 0x%04x already in use\n", wdt_stop);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 ret = -EIO;
251 goto out;
252 }
253 }
254
255 if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
Joe Perches27c766a2012-02-15 15:06:19 -0800256 pr_err("I/O address 0x%04x already in use\n", wdt_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 ret = -EIO;
258 goto unreg_stop;
259 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 ret = misc_register(&acq_miscdev);
261 if (ret != 0) {
Joe Perches27c766a2012-02-15 15:06:19 -0800262 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
263 WATCHDOG_MINOR, ret);
Wim Van Sebroeck98c08e92007-01-10 23:38:56 +0100264 goto unreg_regions;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 }
Joe Perches27c766a2012-02-15 15:06:19 -0800266 pr_info("initialized. (nowayout=%d)\n", nowayout);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267
268 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269unreg_regions:
270 release_region(wdt_start, 1);
271unreg_stop:
272 if (wdt_stop != wdt_start)
273 release_region(wdt_stop, 1);
274out:
275 return ret;
276}
277
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +0100278static int __devexit acq_remove(struct platform_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279{
280 misc_deregister(&acq_miscdev);
Alan Cox94da1e22008-05-19 14:04:46 +0100281 release_region(wdt_start, 1);
282 if (wdt_stop != wdt_start)
283 release_region(wdt_stop, 1);
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +0100284
285 return 0;
286}
287
Wim Van Sebroeck98c08e92007-01-10 23:38:56 +0100288static void acq_shutdown(struct platform_device *dev)
289{
290 /* Turn the WDT off if we have a soft shutdown */
291 acq_stop();
292}
293
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +0100294static struct platform_driver acquirewdt_driver = {
295 .probe = acq_probe,
296 .remove = __devexit_p(acq_remove),
Wim Van Sebroeck98c08e92007-01-10 23:38:56 +0100297 .shutdown = acq_shutdown,
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +0100298 .driver = {
299 .owner = THIS_MODULE,
300 .name = DRV_NAME,
301 },
302};
303
304static int __init acq_init(void)
305{
306 int err;
307
Joe Perches27c766a2012-02-15 15:06:19 -0800308 pr_info("WDT driver for Acquire single board computer initialising\n");
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +0100309
310 err = platform_driver_register(&acquirewdt_driver);
311 if (err)
312 return err;
313
Alan Cox94da1e22008-05-19 14:04:46 +0100314 acq_platform_device = platform_device_register_simple(DRV_NAME,
315 -1, NULL, 0);
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +0100316 if (IS_ERR(acq_platform_device)) {
317 err = PTR_ERR(acq_platform_device);
318 goto unreg_platform_driver;
319 }
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +0100320 return 0;
321
322unreg_platform_driver:
323 platform_driver_unregister(&acquirewdt_driver);
324 return err;
325}
326
327static void __exit acq_exit(void)
328{
329 platform_device_unregister(acq_platform_device);
330 platform_driver_unregister(&acquirewdt_driver);
Joe Perches27c766a2012-02-15 15:06:19 -0800331 pr_info("Watchdog Module Unloaded\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332}
333
334module_init(acq_init);
335module_exit(acq_exit);
336
337MODULE_AUTHOR("David Woodhouse");
338MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver");
339MODULE_LICENSE("GPL");
340MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);