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1da177e4 LT |
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 | ||
1da177e4 LT |
20 | #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> | |
28 | #include <linux/pci.h> | |
29 | #include <linux/scx200.h> | |
30 | ||
31 | #include <asm/uaccess.h> | |
32 | #include <asm/io.h> | |
33 | ||
34 | #define NAME "scx200_wdt" | |
35 | ||
36 | MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>"); | |
37 | MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver"); | |
38 | MODULE_LICENSE("GPL"); | |
39 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
40 | ||
1da177e4 LT |
41 | static int margin = 60; /* in seconds */ |
42 | module_param(margin, int, 0); | |
43 | MODULE_PARM_DESC(margin, "Watchdog margin in seconds"); | |
44 | ||
4bfdf378 | 45 | static int nowayout = WATCHDOG_NOWAYOUT; |
1da177e4 LT |
46 | module_param(nowayout, int, 0); |
47 | MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close"); | |
48 | ||
49 | static u16 wdto_restart; | |
50 | static struct semaphore open_semaphore; | |
51 | static char expect_close; | |
52 | ||
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 | ||
60 | static void scx200_wdt_ping(void) | |
61 | { | |
62 | outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO); | |
63 | } | |
64 | ||
65 | static void scx200_wdt_update_margin(void) | |
66 | { | |
67 | printk(KERN_INFO NAME ": timer margin %d seconds\n", margin); | |
68 | wdto_restart = margin * W_SCALE; | |
69 | } | |
70 | ||
71 | static void scx200_wdt_enable(void) | |
72 | { | |
73 | printk(KERN_DEBUG NAME ": enabling watchdog timer, wdto_restart = %d\n", | |
74 | wdto_restart); | |
75 | ||
76 | outw(0, scx200_cb_base + SCx200_WDT_WDTO); | |
77 | outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS); | |
78 | outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG); | |
79 | ||
80 | scx200_wdt_ping(); | |
81 | } | |
82 | ||
83 | static void scx200_wdt_disable(void) | |
84 | { | |
85 | printk(KERN_DEBUG NAME ": disabling watchdog timer\n"); | |
86 | ||
87 | outw(0, scx200_cb_base + SCx200_WDT_WDTO); | |
88 | outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS); | |
89 | outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG); | |
90 | } | |
91 | ||
92 | static int scx200_wdt_open(struct inode *inode, struct file *file) | |
93 | { | |
94 | /* only allow one at a time */ | |
95 | if (down_trylock(&open_semaphore)) | |
96 | return -EBUSY; | |
97 | scx200_wdt_enable(); | |
98 | ||
99 | return nonseekable_open(inode, file); | |
100 | } | |
101 | ||
102 | static int scx200_wdt_release(struct inode *inode, struct file *file) | |
103 | { | |
104 | if (expect_close != 42) { | |
105 | printk(KERN_WARNING NAME ": watchdog device closed unexpectedly, will not disable the watchdog timer\n"); | |
106 | } else if (!nowayout) { | |
107 | scx200_wdt_disable(); | |
108 | } | |
109 | expect_close = 0; | |
110 | up(&open_semaphore); | |
111 | ||
112 | return 0; | |
113 | } | |
114 | ||
115 | static int scx200_wdt_notify_sys(struct notifier_block *this, | |
116 | unsigned long code, void *unused) | |
117 | { | |
118 | if (code == SYS_HALT || code == SYS_POWER_OFF) | |
119 | if (!nowayout) | |
120 | scx200_wdt_disable(); | |
121 | ||
122 | return NOTIFY_DONE; | |
123 | } | |
124 | ||
125 | static struct notifier_block scx200_wdt_notifier = | |
126 | { | |
127 | .notifier_call = scx200_wdt_notify_sys, | |
128 | }; | |
129 | ||
130 | static ssize_t scx200_wdt_write(struct file *file, const char __user *data, | |
131 | size_t len, loff_t *ppos) | |
132 | { | |
133 | /* check for a magic close character */ | |
134 | if (len) | |
135 | { | |
136 | size_t i; | |
137 | ||
138 | scx200_wdt_ping(); | |
139 | ||
140 | expect_close = 0; | |
141 | for (i = 0; i < len; ++i) { | |
142 | char c; | |
143 | if (get_user(c, data+i)) | |
144 | return -EFAULT; | |
145 | if (c == 'V') | |
146 | expect_close = 42; | |
147 | } | |
148 | ||
149 | return len; | |
150 | } | |
151 | ||
152 | return 0; | |
153 | } | |
154 | ||
155 | static int scx200_wdt_ioctl(struct inode *inode, struct file *file, | |
156 | unsigned int cmd, unsigned long arg) | |
157 | { | |
158 | void __user *argp = (void __user *)arg; | |
159 | int __user *p = argp; | |
160 | static struct watchdog_info ident = { | |
161 | .identity = "NatSemi SCx200 Watchdog", | |
162 | .firmware_version = 1, | |
163 | .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING), | |
164 | }; | |
165 | int new_margin; | |
166 | ||
167 | switch (cmd) { | |
168 | default: | |
169 | return -ENOIOCTLCMD; | |
170 | case WDIOC_GETSUPPORT: | |
171 | if(copy_to_user(argp, &ident, sizeof(ident))) | |
172 | return -EFAULT; | |
173 | return 0; | |
174 | case WDIOC_GETSTATUS: | |
175 | case WDIOC_GETBOOTSTATUS: | |
176 | if (put_user(0, p)) | |
177 | return -EFAULT; | |
178 | return 0; | |
179 | case WDIOC_KEEPALIVE: | |
180 | scx200_wdt_ping(); | |
181 | return 0; | |
182 | case WDIOC_SETTIMEOUT: | |
183 | if (get_user(new_margin, p)) | |
184 | return -EFAULT; | |
185 | if (new_margin < 1) | |
186 | return -EINVAL; | |
187 | margin = new_margin; | |
188 | scx200_wdt_update_margin(); | |
189 | scx200_wdt_ping(); | |
190 | case WDIOC_GETTIMEOUT: | |
191 | if (put_user(margin, p)) | |
192 | return -EFAULT; | |
193 | return 0; | |
194 | } | |
195 | } | |
196 | ||
197 | static struct file_operations scx200_wdt_fops = { | |
198 | .owner = THIS_MODULE, | |
199 | .llseek = no_llseek, | |
200 | .write = scx200_wdt_write, | |
201 | .ioctl = scx200_wdt_ioctl, | |
202 | .open = scx200_wdt_open, | |
203 | .release = scx200_wdt_release, | |
204 | }; | |
205 | ||
206 | static struct miscdevice scx200_wdt_miscdev = { | |
207 | .minor = WATCHDOG_MINOR, | |
2dab3cab | 208 | .name = "watchdog", |
1da177e4 LT |
209 | .fops = &scx200_wdt_fops, |
210 | }; | |
211 | ||
212 | static int __init scx200_wdt_init(void) | |
213 | { | |
214 | int r; | |
215 | ||
216 | printk(KERN_DEBUG NAME ": NatSemi SCx200 Watchdog Driver\n"); | |
217 | ||
218 | /* check that we have found the configuration block */ | |
219 | if (!scx200_cb_present()) | |
220 | return -ENODEV; | |
221 | ||
222 | if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET, | |
223 | SCx200_WDT_SIZE, | |
224 | "NatSemi SCx200 Watchdog")) { | |
225 | printk(KERN_WARNING NAME ": watchdog I/O region busy\n"); | |
226 | return -EBUSY; | |
227 | } | |
228 | ||
229 | scx200_wdt_update_margin(); | |
230 | scx200_wdt_disable(); | |
231 | ||
232 | sema_init(&open_semaphore, 1); | |
233 | ||
234 | r = misc_register(&scx200_wdt_miscdev); | |
235 | if (r) { | |
236 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, | |
237 | SCx200_WDT_SIZE); | |
238 | return r; | |
239 | } | |
240 | ||
241 | r = register_reboot_notifier(&scx200_wdt_notifier); | |
242 | if (r) { | |
243 | printk(KERN_ERR NAME ": unable to register reboot notifier"); | |
244 | misc_deregister(&scx200_wdt_miscdev); | |
245 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, | |
246 | SCx200_WDT_SIZE); | |
247 | return r; | |
248 | } | |
249 | ||
250 | return 0; | |
251 | } | |
252 | ||
253 | static void __exit scx200_wdt_cleanup(void) | |
254 | { | |
255 | unregister_reboot_notifier(&scx200_wdt_notifier); | |
256 | misc_deregister(&scx200_wdt_miscdev); | |
257 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, | |
258 | SCx200_WDT_SIZE); | |
259 | } | |
260 | ||
261 | module_init(scx200_wdt_init); | |
262 | module_exit(scx200_wdt_cleanup); | |
263 | ||
264 | /* | |
265 | Local variables: | |
266 | compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules" | |
267 | c-basic-offset: 8 | |
268 | End: | |
269 | */ |