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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* drivers/char/watchdog/scx200_wdt.c
2
3 National Semiconductor SCx200 Watchdog support
4
5 Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
6
7 Some code taken from:
8 National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
9 (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>
10
11 This program is free software; you can redistribute it and/or
12 modify it under the terms of the GNU General Public License as
13 published by the Free Software Foundation; either version 2 of the
14 License, or (at your option) any later version.
15
16 The author(s) of this software shall not be held liable for damages
17 of any nature resulting due to the use of this software. This
18 software is provided AS-IS with no warranties. */
19
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include <linux/module.h>
21#include <linux/moduleparam.h>
22#include <linux/init.h>
23#include <linux/miscdevice.h>
24#include <linux/watchdog.h>
25#include <linux/notifier.h>
26#include <linux/reboot.h>
27#include <linux/fs.h>
Jean Delvare6473d162007-03-06 02:45:12 -080028#include <linux/ioport.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029#include <linux/scx200.h>
Alan Cox9b748ed2008-05-19 14:08:49 +010030#include <linux/uaccess.h>
31#include <linux/io.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
33#define NAME "scx200_wdt"
34
35MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
36MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver");
37MODULE_LICENSE("GPL");
38MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
39
Linus Torvalds1da177e2005-04-16 15:20:36 -070040static int margin = 60; /* in seconds */
41module_param(margin, int, 0);
42MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
43
Andrey Panin4bfdf372005-07-27 11:43:58 -070044static int nowayout = WATCHDOG_NOWAYOUT;
Linus Torvalds1da177e2005-04-16 15:20:36 -070045module_param(nowayout, int, 0);
46MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
47
48static u16 wdto_restart;
Linus Torvalds1da177e2005-04-16 15:20:36 -070049static char expect_close;
Alan Cox9b748ed2008-05-19 14:08:49 +010050static unsigned long open_lock;
51static DEFINE_SPINLOCK(scx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
53/* Bits of the WDCNFG register */
54#define W_ENABLE 0x00fa /* Enable watchdog */
55#define W_DISABLE 0x0000 /* Disable watchdog */
56
57/* The scaling factor for the timer, this depends on the value of W_ENABLE */
58#define W_SCALE (32768/1024)
59
60static void scx200_wdt_ping(void)
61{
Alan Cox9b748ed2008-05-19 14:08:49 +010062 spin_lock(&scx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO);
Alan Cox9b748ed2008-05-19 14:08:49 +010064 spin_unlock(&scx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065}
66
67static void scx200_wdt_update_margin(void)
68{
69 printk(KERN_INFO NAME ": timer margin %d seconds\n", margin);
70 wdto_restart = margin * W_SCALE;
71}
72
73static void scx200_wdt_enable(void)
74{
75 printk(KERN_DEBUG NAME ": enabling watchdog timer, wdto_restart = %d\n",
76 wdto_restart);
77
Alan Cox9b748ed2008-05-19 14:08:49 +010078 spin_lock(&scx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 outw(0, scx200_cb_base + SCx200_WDT_WDTO);
80 outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
81 outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
Alan Cox9b748ed2008-05-19 14:08:49 +010082 spin_unlock(&scx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070083
84 scx200_wdt_ping();
85}
86
87static void scx200_wdt_disable(void)
88{
89 printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
90
Alan Cox9b748ed2008-05-19 14:08:49 +010091 spin_lock(&scx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 outw(0, scx200_cb_base + SCx200_WDT_WDTO);
93 outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
94 outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
Alan Cox9b748ed2008-05-19 14:08:49 +010095 spin_unlock(&scx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070096}
97
98static int scx200_wdt_open(struct inode *inode, struct file *file)
99{
100 /* only allow one at a time */
Alan Cox9b748ed2008-05-19 14:08:49 +0100101 if (test_and_set_bit(0, &open_lock))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 return -EBUSY;
103 scx200_wdt_enable();
104
105 return nonseekable_open(inode, file);
106}
107
108static int scx200_wdt_release(struct inode *inode, struct file *file)
109{
Alan Cox9b748ed2008-05-19 14:08:49 +0100110 if (expect_close != 42)
Wim Van Sebroecka77dba72009-04-14 20:20:07 +0000111 printk(KERN_WARNING NAME
112 ": watchdog device closed unexpectedly, "
113 "will not disable the watchdog timer\n");
Alan Cox9b748ed2008-05-19 14:08:49 +0100114 else if (!nowayout)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 scx200_wdt_disable();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 expect_close = 0;
Alan Cox9b748ed2008-05-19 14:08:49 +0100117 clear_bit(0, &open_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118
119 return 0;
120}
121
122static int scx200_wdt_notify_sys(struct notifier_block *this,
123 unsigned long code, void *unused)
124{
125 if (code == SYS_HALT || code == SYS_POWER_OFF)
126 if (!nowayout)
127 scx200_wdt_disable();
128
129 return NOTIFY_DONE;
130}
131
Alan Cox9b748ed2008-05-19 14:08:49 +0100132static struct notifier_block scx200_wdt_notifier = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 .notifier_call = scx200_wdt_notify_sys,
134};
135
136static ssize_t scx200_wdt_write(struct file *file, const char __user *data,
137 size_t len, loff_t *ppos)
138{
139 /* check for a magic close character */
Alan Cox9b748ed2008-05-19 14:08:49 +0100140 if (len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 size_t i;
142
143 scx200_wdt_ping();
144
145 expect_close = 0;
146 for (i = 0; i < len; ++i) {
147 char c;
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000148 if (get_user(c, data + i))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 return -EFAULT;
150 if (c == 'V')
151 expect_close = 42;
152 }
153
154 return len;
155 }
156
157 return 0;
158}
159
Alan Cox9b748ed2008-05-19 14:08:49 +0100160static long scx200_wdt_ioctl(struct file *file, unsigned int cmd,
161 unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162{
163 void __user *argp = (void __user *)arg;
164 int __user *p = argp;
Alan Cox9b748ed2008-05-19 14:08:49 +0100165 static const struct watchdog_info ident = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 .identity = "NatSemi SCx200 Watchdog",
167 .firmware_version = 1,
Wim Van Sebroecke73a7802009-05-11 18:33:00 +0000168 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
169 WDIOF_MAGICCLOSE,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 };
171 int new_margin;
172
173 switch (cmd) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 case WDIOC_GETSUPPORT:
Alan Cox9b748ed2008-05-19 14:08:49 +0100175 if (copy_to_user(argp, &ident, sizeof(ident)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 return -EFAULT;
177 return 0;
178 case WDIOC_GETSTATUS:
179 case WDIOC_GETBOOTSTATUS:
180 if (put_user(0, p))
181 return -EFAULT;
182 return 0;
183 case WDIOC_KEEPALIVE:
184 scx200_wdt_ping();
185 return 0;
186 case WDIOC_SETTIMEOUT:
187 if (get_user(new_margin, p))
188 return -EFAULT;
189 if (new_margin < 1)
190 return -EINVAL;
191 margin = new_margin;
192 scx200_wdt_update_margin();
193 scx200_wdt_ping();
194 case WDIOC_GETTIMEOUT:
195 if (put_user(margin, p))
196 return -EFAULT;
197 return 0;
Wim Van Sebroeck0c06090c2008-07-18 11:41:17 +0000198 default:
199 return -ENOTTY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 }
201}
202
Arjan van de Ven62322d22006-07-03 00:24:21 -0700203static const struct file_operations scx200_wdt_fops = {
Alan Cox9b748ed2008-05-19 14:08:49 +0100204 .owner = THIS_MODULE,
205 .llseek = no_llseek,
206 .write = scx200_wdt_write,
207 .unlocked_ioctl = scx200_wdt_ioctl,
208 .open = scx200_wdt_open,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 .release = scx200_wdt_release,
210};
211
212static struct miscdevice scx200_wdt_miscdev = {
213 .minor = WATCHDOG_MINOR,
Alan Cox9b748ed2008-05-19 14:08:49 +0100214 .name = "watchdog",
215 .fops = &scx200_wdt_fops,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216};
217
218static int __init scx200_wdt_init(void)
219{
220 int r;
221
222 printk(KERN_DEBUG NAME ": NatSemi SCx200 Watchdog Driver\n");
223
224 /* check that we have found the configuration block */
225 if (!scx200_cb_present())
226 return -ENODEV;
227
228 if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET,
229 SCx200_WDT_SIZE,
230 "NatSemi SCx200 Watchdog")) {
231 printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
232 return -EBUSY;
233 }
234
235 scx200_wdt_update_margin();
236 scx200_wdt_disable();
237
Wim Van Sebroeckc6cb13a2007-12-26 20:32:51 +0000238 r = register_reboot_notifier(&scx200_wdt_notifier);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 if (r) {
Wim Van Sebroeckc6cb13a2007-12-26 20:32:51 +0000240 printk(KERN_ERR NAME ": unable to register reboot notifier");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
242 SCx200_WDT_SIZE);
243 return r;
244 }
245
Wim Van Sebroeckc6cb13a2007-12-26 20:32:51 +0000246 r = misc_register(&scx200_wdt_miscdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 if (r) {
Wim Van Sebroeckc6cb13a2007-12-26 20:32:51 +0000248 unregister_reboot_notifier(&scx200_wdt_notifier);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
250 SCx200_WDT_SIZE);
251 return r;
252 }
253
254 return 0;
255}
256
257static void __exit scx200_wdt_cleanup(void)
258{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 misc_deregister(&scx200_wdt_miscdev);
Wim Van Sebroeckc6cb13a2007-12-26 20:32:51 +0000260 unregister_reboot_notifier(&scx200_wdt_notifier);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
262 SCx200_WDT_SIZE);
263}
264
265module_init(scx200_wdt_init);
266module_exit(scx200_wdt_cleanup);
267
268/*
269 Local variables:
Alan Cox9b748ed2008-05-19 14:08:49 +0100270 compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"
271 c-basic-offset: 8
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 End:
273*/