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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/... */
Jean Delvare487722c2013-10-21 17:38:49 +020063#include <linux/miscdevice.h> /* For struct miscdevice */
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +010064#include <linux/watchdog.h> /* For the watchdog specific items */
65#include <linux/fs.h> /* For file operations */
66#include <linux/ioport.h> /* For io-port access */
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +010067#include <linux/platform_device.h> /* For platform_driver framework */
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +010068#include <linux/init.h> /* For __init/__exit/... */
Alan Cox94da1e22008-05-19 14:04:46 +010069#include <linux/uaccess.h> /* For copy_to_user/put_user/... */
70#include <linux/io.h> /* For inb/outb/... */
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +010071
72/* Module information */
73#define DRV_NAME "acquirewdt"
Linus Torvalds1da177e2005-04-16 15:20:36 -070074#define WATCHDOG_NAME "Acquire WDT"
Alan Cox94da1e22008-05-19 14:04:46 +010075/* There is no way to see what the correct time-out period is */
76#define WATCHDOG_HEARTBEAT 0
Linus Torvalds1da177e2005-04-16 15:20:36 -070077
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +010078/* internal variables */
Alan Cox94da1e22008-05-19 14:04:46 +010079/* the watchdog platform device */
80static struct platform_device *acq_platform_device;
Linus Torvalds1da177e2005-04-16 15:20:36 -070081static unsigned long acq_is_open;
82static char expect_close;
83
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +010084/* module parameters */
Alan Cox94da1e22008-05-19 14:04:46 +010085/* You must set this - there is no sane way to probe for this board. */
86static int wdt_stop = 0x43;
Linus Torvalds1da177e2005-04-16 15:20:36 -070087module_param(wdt_stop, int, 0);
88MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)");
89
Alan Cox94da1e22008-05-19 14:04:46 +010090/* You must set this - there is no sane way to probe for this board. */
91static int wdt_start = 0x443;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092module_param(wdt_start, int, 0);
93MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)");
94
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010095static bool nowayout = WATCHDOG_NOWAYOUT;
96module_param(nowayout, bool, 0);
Alan Cox94da1e22008-05-19 14:04:46 +010097MODULE_PARM_DESC(nowayout,
98 "Watchdog cannot be stopped once started (default="
99 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100
101/*
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +0100102 * Watchdog Operations
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 */
104
105static void acq_keepalive(void)
106{
107 /* Write a watchdog value */
108 inb_p(wdt_start);
109}
110
111static void acq_stop(void)
112{
113 /* Turn the card off */
114 inb_p(wdt_stop);
115}
116
117/*
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +0100118 * /dev/watchdog handling
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 */
120
Alan Cox94da1e22008-05-19 14:04:46 +0100121static ssize_t acq_write(struct file *file, const char __user *buf,
122 size_t count, loff_t *ppos)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123{
124 /* See if we got the magic character 'V' and reload the timer */
Alan Cox94da1e22008-05-19 14:04:46 +0100125 if (count) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 if (!nowayout) {
127 size_t i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 /* note: just in case someone wrote the magic character
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000129 five months ago... */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 expect_close = 0;
Alan Cox94da1e22008-05-19 14:04:46 +0100131 /* scan to see whether or not we got the
132 magic character */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 for (i = 0; i != count; i++) {
134 char c;
135 if (get_user(c, buf + i))
136 return -EFAULT;
137 if (c == 'V')
138 expect_close = 42;
139 }
140 }
Alan Cox94da1e22008-05-19 14:04:46 +0100141 /* Well, anyhow someone wrote to us, we should
142 return that favour */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 acq_keepalive();
144 }
145 return count;
146}
147
Alan Cox94da1e22008-05-19 14:04:46 +0100148static long acq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149{
150 int options, retval = -EINVAL;
151 void __user *argp = (void __user *)arg;
152 int __user *p = argp;
Wim Van Sebroeck42747d72009-12-26 18:55:22 +0000153 static const struct watchdog_info ident = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
155 .firmware_version = 1,
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +0100156 .identity = WATCHDOG_NAME,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 };
158
Alan Cox94da1e22008-05-19 14:04:46 +0100159 switch (cmd) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 case WDIOC_GETSUPPORT:
Alan Cox94da1e22008-05-19 14:04:46 +0100161 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162
163 case WDIOC_GETSTATUS:
164 case WDIOC_GETBOOTSTATUS:
Alan Cox94da1e22008-05-19 14:04:46 +0100165 return put_user(0, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 case WDIOC_SETOPTIONS:
168 {
Alan Cox94da1e22008-05-19 14:04:46 +0100169 if (get_user(options, p))
170 return -EFAULT;
171 if (options & WDIOS_DISABLECARD) {
172 acq_stop();
173 retval = 0;
174 }
175 if (options & WDIOS_ENABLECARD) {
176 acq_keepalive();
177 retval = 0;
178 }
179 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 }
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000181 case WDIOC_KEEPALIVE:
182 acq_keepalive();
183 return 0;
184
185 case WDIOC_GETTIMEOUT:
186 return put_user(WATCHDOG_HEARTBEAT, p);
187
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 default:
Alan Cox94da1e22008-05-19 14:04:46 +0100189 return -ENOTTY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 }
191}
192
193static int acq_open(struct inode *inode, struct file *file)
194{
195 if (test_and_set_bit(0, &acq_is_open))
196 return -EBUSY;
197
198 if (nowayout)
199 __module_get(THIS_MODULE);
200
201 /* Activate */
202 acq_keepalive();
203 return nonseekable_open(inode, file);
204}
205
206static int acq_close(struct inode *inode, struct file *file)
207{
208 if (expect_close == 42) {
209 acq_stop();
210 } else {
Joe Perches27c766a2012-02-15 15:06:19 -0800211 pr_crit("Unexpected close, not stopping watchdog!\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 acq_keepalive();
213 }
214 clear_bit(0, &acq_is_open);
215 expect_close = 0;
216 return 0;
217}
218
219/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 * Kernel Interfaces
221 */
222
Arjan van de Ven62322d22006-07-03 00:24:21 -0700223static const struct file_operations acq_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 .owner = THIS_MODULE,
225 .llseek = no_llseek,
226 .write = acq_write,
Alan Cox94da1e22008-05-19 14:04:46 +0100227 .unlocked_ioctl = acq_ioctl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 .open = acq_open,
229 .release = acq_close,
230};
231
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +0100232static struct miscdevice acq_miscdev = {
233 .minor = WATCHDOG_MINOR,
234 .name = "watchdog",
235 .fops = &acq_fops,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236};
237
238/*
Wim Van Sebroeck76c11f02007-01-10 23:23:44 +0100239 * Init & exit routines
240 */
241
Jean Delvareb0e0b4b2014-03-14 13:04:37 +0100242static int __init acq_probe(struct platform_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243{
244 int ret;
245
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 if (wdt_stop != wdt_start) {
247 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
Joe Perches27c766a2012-02-15 15:06:19 -0800248 pr_err("I/O address 0x%04x already in use\n", wdt_stop);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 ret = -EIO;
250 goto out;
251 }
252 }
253
254 if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
Joe Perches27c766a2012-02-15 15:06:19 -0800255 pr_err("I/O address 0x%04x already in use\n", wdt_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 ret = -EIO;
257 goto unreg_stop;
258 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 ret = misc_register(&acq_miscdev);
260 if (ret != 0) {
Joe Perches27c766a2012-02-15 15:06:19 -0800261 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
262 WATCHDOG_MINOR, ret);
Wim Van Sebroeck98c08e92007-01-10 23:38:56 +0100263 goto unreg_regions;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 }
Joe Perches27c766a2012-02-15 15:06:19 -0800265 pr_info("initialized. (nowayout=%d)\n", nowayout);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266
267 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268unreg_regions:
269 release_region(wdt_start, 1);
270unreg_stop:
271 if (wdt_stop != wdt_start)
272 release_region(wdt_stop, 1);
273out:
274 return ret;
275}
276
Bill Pemberton4b12b892012-11-19 13:26:24 -0500277static int acq_remove(struct platform_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278{
279 misc_deregister(&acq_miscdev);
Alan Cox94da1e22008-05-19 14:04:46 +0100280 release_region(wdt_start, 1);
281 if (wdt_stop != wdt_start)
282 release_region(wdt_stop, 1);
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +0100283
284 return 0;
285}
286
Wim Van Sebroeck98c08e92007-01-10 23:38:56 +0100287static void acq_shutdown(struct platform_device *dev)
288{
289 /* Turn the WDT off if we have a soft shutdown */
290 acq_stop();
291}
292
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +0100293static struct platform_driver acquirewdt_driver = {
Bill Pemberton82268712012-11-19 13:21:12 -0500294 .remove = acq_remove,
Wim Van Sebroeck98c08e92007-01-10 23:38:56 +0100295 .shutdown = acq_shutdown,
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +0100296 .driver = {
297 .owner = THIS_MODULE,
298 .name = DRV_NAME,
299 },
300};
301
302static int __init acq_init(void)
303{
304 int err;
305
Joe Perches27c766a2012-02-15 15:06:19 -0800306 pr_info("WDT driver for Acquire single board computer initialising\n");
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +0100307
Alan Cox94da1e22008-05-19 14:04:46 +0100308 acq_platform_device = platform_device_register_simple(DRV_NAME,
309 -1, NULL, 0);
Jean Delvareb0e0b4b2014-03-14 13:04:37 +0100310 if (IS_ERR(acq_platform_device))
311 return PTR_ERR(acq_platform_device);
312
313 err = platform_driver_probe(&acquirewdt_driver, acq_probe);
314 if (err)
315 goto unreg_platform_device;
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +0100316 return 0;
317
Jean Delvareb0e0b4b2014-03-14 13:04:37 +0100318unreg_platform_device:
319 platform_device_unregister(acq_platform_device);
Wim Van Sebroeckad5fe322007-01-10 23:36:13 +0100320 return err;
321}
322
323static void __exit acq_exit(void)
324{
325 platform_device_unregister(acq_platform_device);
326 platform_driver_unregister(&acquirewdt_driver);
Joe Perches27c766a2012-02-15 15:06:19 -0800327 pr_info("Watchdog Module Unloaded\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328}
329
330module_init(acq_init);
331module_exit(acq_exit);
332
333MODULE_AUTHOR("David Woodhouse");
334MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver");
335MODULE_LICENSE("GPL");