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-rw-r--r--drivers/char/watchdog/scx200_wdt.c274
1 files changed, 274 insertions, 0 deletions
diff --git a/drivers/char/watchdog/scx200_wdt.c b/drivers/char/watchdog/scx200_wdt.c
new file mode 100644
index 000000000000..b569670e4ed5
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+++ b/drivers/char/watchdog/scx200_wdt.c
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1/* 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
20#include <linux/config.h>
21#include <linux/module.h>
22#include <linux/moduleparam.h>
23#include <linux/init.h>
24#include <linux/miscdevice.h>
25#include <linux/watchdog.h>
26#include <linux/notifier.h>
27#include <linux/reboot.h>
28#include <linux/fs.h>
29#include <linux/pci.h>
30#include <linux/scx200.h>
31
32#include <asm/uaccess.h>
33#include <asm/io.h>
34
35#define NAME "scx200_wdt"
36
37MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
38MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver");
39MODULE_LICENSE("GPL");
40MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
41
42#ifndef CONFIG_WATCHDOG_NOWAYOUT
43#define CONFIG_WATCHDOG_NOWAYOUT 0
44#endif
45
46static int margin = 60; /* in seconds */
47module_param(margin, int, 0);
48MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
49
50static int nowayout = CONFIG_WATCHDOG_NOWAYOUT;
51module_param(nowayout, int, 0);
52MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
53
54static u16 wdto_restart;
55static struct semaphore open_semaphore;
56static char expect_close;
57
58/* Bits of the WDCNFG register */
59#define W_ENABLE 0x00fa /* Enable watchdog */
60#define W_DISABLE 0x0000 /* Disable watchdog */
61
62/* The scaling factor for the timer, this depends on the value of W_ENABLE */
63#define W_SCALE (32768/1024)
64
65static void scx200_wdt_ping(void)
66{
67 outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO);
68}
69
70static void scx200_wdt_update_margin(void)
71{
72 printk(KERN_INFO NAME ": timer margin %d seconds\n", margin);
73 wdto_restart = margin * W_SCALE;
74}
75
76static void scx200_wdt_enable(void)
77{
78 printk(KERN_DEBUG NAME ": enabling watchdog timer, wdto_restart = %d\n",
79 wdto_restart);
80
81 outw(0, scx200_cb_base + SCx200_WDT_WDTO);
82 outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
83 outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
84
85 scx200_wdt_ping();
86}
87
88static void scx200_wdt_disable(void)
89{
90 printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
91
92 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);
95}
96
97static int scx200_wdt_open(struct inode *inode, struct file *file)
98{
99 /* only allow one at a time */
100 if (down_trylock(&open_semaphore))
101 return -EBUSY;
102 scx200_wdt_enable();
103
104 return nonseekable_open(inode, file);
105}
106
107static int scx200_wdt_release(struct inode *inode, struct file *file)
108{
109 if (expect_close != 42) {
110 printk(KERN_WARNING NAME ": watchdog device closed unexpectedly, will not disable the watchdog timer\n");
111 } else if (!nowayout) {
112 scx200_wdt_disable();
113 }
114 expect_close = 0;
115 up(&open_semaphore);
116
117 return 0;
118}
119
120static int scx200_wdt_notify_sys(struct notifier_block *this,
121 unsigned long code, void *unused)
122{
123 if (code == SYS_HALT || code == SYS_POWER_OFF)
124 if (!nowayout)
125 scx200_wdt_disable();
126
127 return NOTIFY_DONE;
128}
129
130static struct notifier_block scx200_wdt_notifier =
131{
132 .notifier_call = scx200_wdt_notify_sys,
133};
134
135static ssize_t scx200_wdt_write(struct file *file, const char __user *data,
136 size_t len, loff_t *ppos)
137{
138 /* check for a magic close character */
139 if (len)
140 {
141 size_t i;
142
143 scx200_wdt_ping();
144
145 expect_close = 0;
146 for (i = 0; i < len; ++i) {
147 char c;
148 if (get_user(c, data+i))
149 return -EFAULT;
150 if (c == 'V')
151 expect_close = 42;
152 }
153
154 return len;
155 }
156
157 return 0;
158}
159
160static int scx200_wdt_ioctl(struct inode *inode, struct file *file,
161 unsigned int cmd, unsigned long arg)
162{
163 void __user *argp = (void __user *)arg;
164 int __user *p = argp;
165 static struct watchdog_info ident = {
166 .identity = "NatSemi SCx200 Watchdog",
167 .firmware_version = 1,
168 .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING),
169 };
170 int new_margin;
171
172 switch (cmd) {
173 default:
174 return -ENOIOCTLCMD;
175 case WDIOC_GETSUPPORT:
176 if(copy_to_user(argp, &ident, sizeof(ident)))
177 return -EFAULT;
178 return 0;
179 case WDIOC_GETSTATUS:
180 case WDIOC_GETBOOTSTATUS:
181 if (put_user(0, p))
182 return -EFAULT;
183 return 0;
184 case WDIOC_KEEPALIVE:
185 scx200_wdt_ping();
186 return 0;
187 case WDIOC_SETTIMEOUT:
188 if (get_user(new_margin, p))
189 return -EFAULT;
190 if (new_margin < 1)
191 return -EINVAL;
192 margin = new_margin;
193 scx200_wdt_update_margin();
194 scx200_wdt_ping();
195 case WDIOC_GETTIMEOUT:
196 if (put_user(margin, p))
197 return -EFAULT;
198 return 0;
199 }
200}
201
202static struct file_operations scx200_wdt_fops = {
203 .owner = THIS_MODULE,
204 .llseek = no_llseek,
205 .write = scx200_wdt_write,
206 .ioctl = scx200_wdt_ioctl,
207 .open = scx200_wdt_open,
208 .release = scx200_wdt_release,
209};
210
211static struct miscdevice scx200_wdt_miscdev = {
212 .minor = WATCHDOG_MINOR,
213 .name = NAME,
214 .fops = &scx200_wdt_fops,
215};
216
217static int __init scx200_wdt_init(void)
218{
219 int r;
220
221 printk(KERN_DEBUG NAME ": NatSemi SCx200 Watchdog Driver\n");
222
223 /* check that we have found the configuration block */
224 if (!scx200_cb_present())
225 return -ENODEV;
226
227 if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET,
228 SCx200_WDT_SIZE,
229 "NatSemi SCx200 Watchdog")) {
230 printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
231 return -EBUSY;
232 }
233
234 scx200_wdt_update_margin();
235 scx200_wdt_disable();
236
237 sema_init(&open_semaphore, 1);
238
239 r = misc_register(&scx200_wdt_miscdev);
240 if (r) {
241 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
242 SCx200_WDT_SIZE);
243 return r;
244 }
245
246 r = register_reboot_notifier(&scx200_wdt_notifier);
247 if (r) {
248 printk(KERN_ERR NAME ": unable to register reboot notifier");
249 misc_deregister(&scx200_wdt_miscdev);
250 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
251 SCx200_WDT_SIZE);
252 return r;
253 }
254
255 return 0;
256}
257
258static void __exit scx200_wdt_cleanup(void)
259{
260 unregister_reboot_notifier(&scx200_wdt_notifier);
261 misc_deregister(&scx200_wdt_miscdev);
262 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
263 SCx200_WDT_SIZE);
264}
265
266module_init(scx200_wdt_init);
267module_exit(scx200_wdt_cleanup);
268
269/*
270 Local variables:
271 compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"
272 c-basic-offset: 8
273 End:
274*/