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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 *
Alan Cox29fa0582008-10-27 15:17:56 +000014 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
15 * All Rights Reserved.
Linus Torvalds1da177e2005-04-16 15:20:36 -070016 *
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 *
Alan Cox29fa0582008-10-27 15:17:56 +000026 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027 *
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
Joe Perches27c766a2012-02-15 15:06:19 -080034#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
35
Linus Torvalds1da177e2005-04-16 15:20:36 -070036#include <linux/module.h>
37#include <linux/types.h>
38#include <linux/miscdevice.h>
39#include <linux/watchdog.h>
40#include <linux/ioport.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070041#include <linux/fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070042#include <linux/init.h>
43#include <linux/spinlock.h>
44#include <linux/moduleparam.h>
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +010045#include <linux/platform_device.h>
Alan Cox2e43ba72008-05-19 14:05:52 +010046#include <linux/io.h>
47#include <linux/uaccess.h>
Wim Van Sebroeck089ab072008-07-15 11:46:11 +000048
Linus Torvalds1da177e2005-04-16 15:20:36 -070049
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +010050static struct platform_device *ibwdt_platform_device;
Linus Torvalds1da177e2005-04-16 15:20:36 -070051static unsigned long ibwdt_is_open;
Alexey Dobriyanc7dfd0c2007-11-01 16:27:08 -070052static DEFINE_SPINLOCK(ibwdt_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070053static char expect_close;
54
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +010055/* Module information */
56#define DRV_NAME "ib700wdt"
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070094#define WDT_STOP 0x441
95#define WDT_START 0x443
96
97/* Default timeout */
Wim Van Sebroeck794db262008-10-15 11:44:40 +000098#define WATCHDOG_TIMEOUT 30 /* 30 seconds +/- 20% */
99static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
100module_param(timeout, int, 0);
101MODULE_PARM_DESC(timeout,
102 "Watchdog timeout in seconds. 0<= timeout <=30, default="
103 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +0100105static bool nowayout = WATCHDOG_NOWAYOUT;
106module_param(nowayout, bool, 0);
Alan Cox2e43ba72008-05-19 14:05:52 +0100107MODULE_PARM_DESC(nowayout,
108 "Watchdog cannot be stopped once started (default="
109 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110
111
112/*
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100113 * Watchdog Operations
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 */
115
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000116static void ibwdt_ping(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117{
Wim Van Sebroeck794db262008-10-15 11:44:40 +0000118 int wd_margin = 15 - ((timeout + 1) / 2);
119
Wim Van Sebroecke42162a2007-01-27 22:12:54 +0100120 spin_lock(&ibwdt_lock);
121
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 /* Write a watchdog value */
123 outb_p(wd_margin, WDT_START);
Wim Van Sebroecke42162a2007-01-27 22:12:54 +0100124
125 spin_unlock(&ibwdt_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126}
127
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000128static void ibwdt_disable(void)
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100129{
Wim Van Sebroecke42162a2007-01-27 22:12:54 +0100130 spin_lock(&ibwdt_lock);
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100131 outb_p(0, WDT_STOP);
Wim Van Sebroecke42162a2007-01-27 22:12:54 +0100132 spin_unlock(&ibwdt_lock);
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100133}
134
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000135static int ibwdt_set_heartbeat(int t)
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100136{
Wim Van Sebroeck794db262008-10-15 11:44:40 +0000137 if (t < 0 || t > 30)
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100138 return -EINVAL;
139
Wim Van Sebroeck794db262008-10-15 11:44:40 +0000140 timeout = t;
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100141 return 0;
142}
143
144/*
145 * /dev/watchdog handling
146 */
147
Alan Cox2e43ba72008-05-19 14:05:52 +0100148static ssize_t ibwdt_write(struct file *file, const char __user *buf,
149 size_t count, loff_t *ppos)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150{
151 if (count) {
152 if (!nowayout) {
153 size_t i;
154
155 /* In case it was set long ago */
156 expect_close = 0;
157
158 for (i = 0; i != count; i++) {
159 char c;
160 if (get_user(c, buf + i))
161 return -EFAULT;
162 if (c == 'V')
163 expect_close = 42;
164 }
165 }
166 ibwdt_ping();
167 }
168 return count;
169}
170
Alan Cox2e43ba72008-05-19 14:05:52 +0100171static long ibwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172{
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100173 int new_margin;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 void __user *argp = (void __user *)arg;
175 int __user *p = argp;
176
Wim Van Sebroeck42747d72009-12-26 18:55:22 +0000177 static const struct watchdog_info ident = {
Alan Cox2e43ba72008-05-19 14:05:52 +0100178 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
179 | WDIOF_MAGICCLOSE,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 .firmware_version = 1,
181 .identity = "IB700 WDT",
182 };
183
184 switch (cmd) {
185 case WDIOC_GETSUPPORT:
Alan Cox2e43ba72008-05-19 14:05:52 +0100186 if (copy_to_user(argp, &ident, sizeof(ident)))
187 return -EFAULT;
188 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189
190 case WDIOC_GETSTATUS:
Wim Van Sebroeckc9d77102007-01-27 22:07:03 +0100191 case WDIOC_GETBOOTSTATUS:
Alan Cox2e43ba72008-05-19 14:05:52 +0100192 return put_user(0, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193
Wim Van Sebroecke42162a2007-01-27 22:12:54 +0100194 case WDIOC_SETOPTIONS:
195 {
Alan Cox2e43ba72008-05-19 14:05:52 +0100196 int options, retval = -EINVAL;
Wim Van Sebroecke42162a2007-01-27 22:12:54 +0100197
Alan Cox2e43ba72008-05-19 14:05:52 +0100198 if (get_user(options, p))
199 return -EFAULT;
Wim Van Sebroecke42162a2007-01-27 22:12:54 +0100200
Alan Cox2e43ba72008-05-19 14:05:52 +0100201 if (options & WDIOS_DISABLECARD) {
202 ibwdt_disable();
203 retval = 0;
204 }
205 if (options & WDIOS_ENABLECARD) {
206 ibwdt_ping();
207 retval = 0;
208 }
209 return retval;
Wim Van Sebroecke42162a2007-01-27 22:12:54 +0100210 }
Wim Van Sebroeck0c06090c2008-07-18 11:41:17 +0000211 case WDIOC_KEEPALIVE:
212 ibwdt_ping();
213 break;
214
215 case WDIOC_SETTIMEOUT:
216 if (get_user(new_margin, p))
217 return -EFAULT;
218 if (ibwdt_set_heartbeat(new_margin))
219 return -EINVAL;
220 ibwdt_ping();
221 /* Fall */
222
223 case WDIOC_GETTIMEOUT:
Wim Van Sebroeck794db262008-10-15 11:44:40 +0000224 return put_user(timeout, p);
Wim Van Sebroeck0c06090c2008-07-18 11:41:17 +0000225
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 default:
Alan Cox2e43ba72008-05-19 14:05:52 +0100227 return -ENOTTY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 }
229 return 0;
230}
231
Alan Cox2e43ba72008-05-19 14:05:52 +0100232static int ibwdt_open(struct inode *inode, struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233{
Alan Cox2e43ba72008-05-19 14:05:52 +0100234 if (test_and_set_bit(0, &ibwdt_is_open))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 return -EBUSY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 if (nowayout)
237 __module_get(THIS_MODULE);
238
239 /* Activate */
240 ibwdt_ping();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 return nonseekable_open(inode, file);
242}
243
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000244static int ibwdt_close(struct inode *inode, struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245{
Wim Van Sebroeckc9d77102007-01-27 22:07:03 +0100246 if (expect_close == 42) {
Wim Van Sebroeck35d55c92007-01-27 21:50:53 +0100247 ibwdt_disable();
Wim Van Sebroeckc9d77102007-01-27 22:07:03 +0100248 } else {
Joe Perches27c766a2012-02-15 15:06:19 -0800249 pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");
Wim Van Sebroeckc9d77102007-01-27 22:07:03 +0100250 ibwdt_ping();
251 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 clear_bit(0, &ibwdt_is_open);
253 expect_close = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254 return 0;
255}
256
257/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 * Kernel Interfaces
259 */
260
Arjan van de Ven62322d22006-07-03 00:24:21 -0700261static const struct file_operations ibwdt_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 .owner = THIS_MODULE,
263 .llseek = no_llseek,
264 .write = ibwdt_write,
Alan Cox2e43ba72008-05-19 14:05:52 +0100265 .unlocked_ioctl = ibwdt_ioctl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 .open = ibwdt_open,
267 .release = ibwdt_close,
268};
269
270static struct miscdevice ibwdt_miscdev = {
271 .minor = WATCHDOG_MINOR,
272 .name = "watchdog",
273 .fops = &ibwdt_fops,
274};
275
276/*
Wim Van Sebroeckf6e48032007-01-27 21:58:08 +0100277 * Init & exit routines
278 */
279
Jean Delvare996735f2014-03-14 13:18:47 +0100280static int __init ibwdt_probe(struct platform_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281{
282 int res;
283
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284#if WDT_START != WDT_STOP
285 if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
Joe Perches27c766a2012-02-15 15:06:19 -0800286 pr_err("STOP method I/O %X is not available\n", WDT_STOP);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 res = -EIO;
288 goto out_nostopreg;
289 }
290#endif
291
292 if (!request_region(WDT_START, 1, "IB700 WDT")) {
Joe Perches27c766a2012-02-15 15:06:19 -0800293 pr_err("START method I/O %X is not available\n", WDT_START);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 res = -EIO;
295 goto out_nostartreg;
296 }
Wim Van Sebroeckf6e48032007-01-27 21:58:08 +0100297
Wim Van Sebroeck794db262008-10-15 11:44:40 +0000298 /* Check that the heartbeat value is within it's range ;
299 * if not reset to the default */
300 if (ibwdt_set_heartbeat(timeout)) {
301 ibwdt_set_heartbeat(WATCHDOG_TIMEOUT);
Joe Perches27c766a2012-02-15 15:06:19 -0800302 pr_info("timeout value must be 0<=x<=30, using %d\n", timeout);
Wim Van Sebroeck794db262008-10-15 11:44:40 +0000303 }
304
Wim Van Sebroeckf6e48032007-01-27 21:58:08 +0100305 res = misc_register(&ibwdt_miscdev);
306 if (res) {
Joe Perches27c766a2012-02-15 15:06:19 -0800307 pr_err("failed to register misc device\n");
Wim Van Sebroeckf6e48032007-01-27 21:58:08 +0100308 goto out_nomisc;
309 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 return 0;
311
Wim Van Sebroeckf6e48032007-01-27 21:58:08 +0100312out_nomisc:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 release_region(WDT_START, 1);
314out_nostartreg:
315#if WDT_START != WDT_STOP
316 release_region(WDT_STOP, 1);
317#endif
318out_nostopreg:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 return res;
320}
321
Bill Pemberton4b12b892012-11-19 13:26:24 -0500322static int ibwdt_remove(struct platform_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323{
324 misc_deregister(&ibwdt_miscdev);
Alan Cox2e43ba72008-05-19 14:05:52 +0100325 release_region(WDT_START, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326#if WDT_START != WDT_STOP
Alan Cox2e43ba72008-05-19 14:05:52 +0100327 release_region(WDT_STOP, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328#endif
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +0100329 return 0;
330}
331
Wim Van Sebroeck35fcf532007-01-27 22:54:18 +0100332static void ibwdt_shutdown(struct platform_device *dev)
333{
334 /* Turn the WDT off if we have a soft shutdown */
335 ibwdt_disable();
336}
337
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +0100338static struct platform_driver ibwdt_driver = {
Bill Pemberton82268712012-11-19 13:21:12 -0500339 .remove = ibwdt_remove,
Wim Van Sebroeck35fcf532007-01-27 22:54:18 +0100340 .shutdown = ibwdt_shutdown,
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +0100341 .driver = {
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +0100342 .name = DRV_NAME,
343 },
344};
345
346static int __init ibwdt_init(void)
347{
348 int err;
349
Joe Perches27c766a2012-02-15 15:06:19 -0800350 pr_info("WDT driver for IB700 single board computer initialising\n");
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +0100351
Alan Cox2e43ba72008-05-19 14:05:52 +0100352 ibwdt_platform_device = platform_device_register_simple(DRV_NAME,
353 -1, NULL, 0);
Jean Delvare996735f2014-03-14 13:18:47 +0100354 if (IS_ERR(ibwdt_platform_device))
355 return PTR_ERR(ibwdt_platform_device);
356
357 err = platform_driver_probe(&ibwdt_driver, ibwdt_probe);
358 if (err)
359 goto unreg_platform_device;
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +0100360
361 return 0;
362
Jean Delvare996735f2014-03-14 13:18:47 +0100363unreg_platform_device:
364 platform_device_unregister(ibwdt_platform_device);
Wim Van Sebroeck745ac1ea2007-01-27 22:39:46 +0100365 return err;
366}
367
368static void __exit ibwdt_exit(void)
369{
370 platform_device_unregister(ibwdt_platform_device);
371 platform_driver_unregister(&ibwdt_driver);
Joe Perches27c766a2012-02-15 15:06:19 -0800372 pr_info("Watchdog Module Unloaded\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373}
374
375module_init(ibwdt_init);
376module_exit(ibwdt_exit);
377
378MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
379MODULE_DESCRIPTION("IB700 SBC watchdog driver");
380MODULE_LICENSE("GPL");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381
382/* end of ib700wdt.c */