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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> | |
6473d160 | 28 | #include <linux/ioport.h> |
1da177e4 | 29 | #include <linux/scx200.h> |
9b748ed0 AC |
30 | #include <linux/uaccess.h> |
31 | #include <linux/io.h> | |
1da177e4 LT |
32 | |
33 | #define NAME "scx200_wdt" | |
34 | ||
35 | MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>"); | |
36 | MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver"); | |
37 | MODULE_LICENSE("GPL"); | |
38 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
39 | ||
1da177e4 LT |
40 | static int margin = 60; /* in seconds */ |
41 | module_param(margin, int, 0); | |
42 | MODULE_PARM_DESC(margin, "Watchdog margin in seconds"); | |
43 | ||
4bfdf378 | 44 | static int nowayout = WATCHDOG_NOWAYOUT; |
1da177e4 LT |
45 | module_param(nowayout, int, 0); |
46 | MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close"); | |
47 | ||
48 | static u16 wdto_restart; | |
1da177e4 | 49 | static char expect_close; |
9b748ed0 AC |
50 | static unsigned long open_lock; |
51 | static DEFINE_SPINLOCK(scx_lock); | |
1da177e4 LT |
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 | { | |
9b748ed0 | 62 | spin_lock(&scx_lock); |
1da177e4 | 63 | outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO); |
9b748ed0 | 64 | spin_unlock(&scx_lock); |
1da177e4 LT |
65 | } |
66 | ||
67 | static 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 | ||
73 | static void scx200_wdt_enable(void) | |
74 | { | |
75 | printk(KERN_DEBUG NAME ": enabling watchdog timer, wdto_restart = %d\n", | |
76 | wdto_restart); | |
77 | ||
9b748ed0 | 78 | spin_lock(&scx_lock); |
1da177e4 LT |
79 | 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); | |
9b748ed0 | 82 | spin_unlock(&scx_lock); |
1da177e4 LT |
83 | |
84 | scx200_wdt_ping(); | |
85 | } | |
86 | ||
87 | static void scx200_wdt_disable(void) | |
88 | { | |
89 | printk(KERN_DEBUG NAME ": disabling watchdog timer\n"); | |
90 | ||
9b748ed0 | 91 | spin_lock(&scx_lock); |
1da177e4 LT |
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); | |
9b748ed0 | 95 | spin_unlock(&scx_lock); |
1da177e4 LT |
96 | } |
97 | ||
98 | static int scx200_wdt_open(struct inode *inode, struct file *file) | |
99 | { | |
100 | /* only allow one at a time */ | |
9b748ed0 | 101 | if (test_and_set_bit(0, &open_lock)) |
1da177e4 LT |
102 | return -EBUSY; |
103 | scx200_wdt_enable(); | |
104 | ||
105 | return nonseekable_open(inode, file); | |
106 | } | |
107 | ||
108 | static int scx200_wdt_release(struct inode *inode, struct file *file) | |
109 | { | |
9b748ed0 | 110 | if (expect_close != 42) |
1da177e4 | 111 | printk(KERN_WARNING NAME ": watchdog device closed unexpectedly, will not disable the watchdog timer\n"); |
9b748ed0 | 112 | else if (!nowayout) |
1da177e4 | 113 | scx200_wdt_disable(); |
1da177e4 | 114 | expect_close = 0; |
9b748ed0 | 115 | clear_bit(0, &open_lock); |
1da177e4 LT |
116 | |
117 | return 0; | |
118 | } | |
119 | ||
120 | static 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 | ||
9b748ed0 | 130 | static struct notifier_block scx200_wdt_notifier = { |
1da177e4 LT |
131 | .notifier_call = scx200_wdt_notify_sys, |
132 | }; | |
133 | ||
134 | static ssize_t scx200_wdt_write(struct file *file, const char __user *data, | |
135 | size_t len, loff_t *ppos) | |
136 | { | |
137 | /* check for a magic close character */ | |
9b748ed0 | 138 | if (len) { |
1da177e4 LT |
139 | size_t i; |
140 | ||
141 | scx200_wdt_ping(); | |
142 | ||
143 | expect_close = 0; | |
144 | for (i = 0; i < len; ++i) { | |
145 | char c; | |
7944d3a5 | 146 | if (get_user(c, data + i)) |
1da177e4 LT |
147 | return -EFAULT; |
148 | if (c == 'V') | |
149 | expect_close = 42; | |
150 | } | |
151 | ||
152 | return len; | |
153 | } | |
154 | ||
155 | return 0; | |
156 | } | |
157 | ||
9b748ed0 AC |
158 | static long scx200_wdt_ioctl(struct file *file, unsigned int cmd, |
159 | unsigned long arg) | |
1da177e4 LT |
160 | { |
161 | void __user *argp = (void __user *)arg; | |
162 | int __user *p = argp; | |
9b748ed0 | 163 | static const struct watchdog_info ident = { |
1da177e4 LT |
164 | .identity = "NatSemi SCx200 Watchdog", |
165 | .firmware_version = 1, | |
9b748ed0 | 166 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, |
1da177e4 LT |
167 | }; |
168 | int new_margin; | |
169 | ||
170 | switch (cmd) { | |
1da177e4 | 171 | case WDIOC_GETSUPPORT: |
9b748ed0 | 172 | if (copy_to_user(argp, &ident, sizeof(ident))) |
1da177e4 LT |
173 | return -EFAULT; |
174 | return 0; | |
175 | case WDIOC_GETSTATUS: | |
176 | case WDIOC_GETBOOTSTATUS: | |
177 | if (put_user(0, p)) | |
178 | return -EFAULT; | |
179 | return 0; | |
180 | case WDIOC_KEEPALIVE: | |
181 | scx200_wdt_ping(); | |
182 | return 0; | |
183 | case WDIOC_SETTIMEOUT: | |
184 | if (get_user(new_margin, p)) | |
185 | return -EFAULT; | |
186 | if (new_margin < 1) | |
187 | return -EINVAL; | |
188 | margin = new_margin; | |
189 | scx200_wdt_update_margin(); | |
190 | scx200_wdt_ping(); | |
191 | case WDIOC_GETTIMEOUT: | |
192 | if (put_user(margin, p)) | |
193 | return -EFAULT; | |
194 | return 0; | |
0c06090c WVS |
195 | default: |
196 | return -ENOTTY; | |
1da177e4 LT |
197 | } |
198 | } | |
199 | ||
62322d25 | 200 | static const struct file_operations scx200_wdt_fops = { |
9b748ed0 AC |
201 | .owner = THIS_MODULE, |
202 | .llseek = no_llseek, | |
203 | .write = scx200_wdt_write, | |
204 | .unlocked_ioctl = scx200_wdt_ioctl, | |
205 | .open = scx200_wdt_open, | |
1da177e4 LT |
206 | .release = scx200_wdt_release, |
207 | }; | |
208 | ||
209 | static struct miscdevice scx200_wdt_miscdev = { | |
210 | .minor = WATCHDOG_MINOR, | |
9b748ed0 AC |
211 | .name = "watchdog", |
212 | .fops = &scx200_wdt_fops, | |
1da177e4 LT |
213 | }; |
214 | ||
215 | static int __init scx200_wdt_init(void) | |
216 | { | |
217 | int r; | |
218 | ||
219 | printk(KERN_DEBUG NAME ": NatSemi SCx200 Watchdog Driver\n"); | |
220 | ||
221 | /* check that we have found the configuration block */ | |
222 | if (!scx200_cb_present()) | |
223 | return -ENODEV; | |
224 | ||
225 | if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET, | |
226 | SCx200_WDT_SIZE, | |
227 | "NatSemi SCx200 Watchdog")) { | |
228 | printk(KERN_WARNING NAME ": watchdog I/O region busy\n"); | |
229 | return -EBUSY; | |
230 | } | |
231 | ||
232 | scx200_wdt_update_margin(); | |
233 | scx200_wdt_disable(); | |
234 | ||
c6cb13ae | 235 | r = register_reboot_notifier(&scx200_wdt_notifier); |
1da177e4 | 236 | if (r) { |
c6cb13ae | 237 | printk(KERN_ERR NAME ": unable to register reboot notifier"); |
1da177e4 LT |
238 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
239 | SCx200_WDT_SIZE); | |
240 | return r; | |
241 | } | |
242 | ||
c6cb13ae | 243 | r = misc_register(&scx200_wdt_miscdev); |
1da177e4 | 244 | if (r) { |
c6cb13ae | 245 | unregister_reboot_notifier(&scx200_wdt_notifier); |
1da177e4 LT |
246 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
247 | SCx200_WDT_SIZE); | |
248 | return r; | |
249 | } | |
250 | ||
251 | return 0; | |
252 | } | |
253 | ||
254 | static void __exit scx200_wdt_cleanup(void) | |
255 | { | |
1da177e4 | 256 | misc_deregister(&scx200_wdt_miscdev); |
c6cb13ae | 257 | unregister_reboot_notifier(&scx200_wdt_notifier); |
1da177e4 LT |
258 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
259 | SCx200_WDT_SIZE); | |
260 | } | |
261 | ||
262 | module_init(scx200_wdt_init); | |
263 | module_exit(scx200_wdt_cleanup); | |
264 | ||
265 | /* | |
266 | Local variables: | |
9b748ed0 AC |
267 | compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules" |
268 | c-basic-offset: 8 | |
1da177e4 LT |
269 | End: |
270 | */ |