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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) |
a77dba7e WVS |
111 | printk(KERN_WARNING NAME |
112 | ": watchdog device closed unexpectedly, " | |
113 | "will not disable the watchdog timer\n"); | |
9b748ed0 | 114 | else if (!nowayout) |
1da177e4 | 115 | scx200_wdt_disable(); |
1da177e4 | 116 | expect_close = 0; |
9b748ed0 | 117 | clear_bit(0, &open_lock); |
1da177e4 LT |
118 | |
119 | return 0; | |
120 | } | |
121 | ||
122 | static 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 | ||
9b748ed0 | 132 | static struct notifier_block scx200_wdt_notifier = { |
1da177e4 LT |
133 | .notifier_call = scx200_wdt_notify_sys, |
134 | }; | |
135 | ||
136 | static 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 */ | |
9b748ed0 | 140 | if (len) { |
1da177e4 LT |
141 | size_t i; |
142 | ||
143 | scx200_wdt_ping(); | |
144 | ||
145 | expect_close = 0; | |
146 | for (i = 0; i < len; ++i) { | |
147 | char c; | |
7944d3a5 | 148 | if (get_user(c, data + i)) |
1da177e4 LT |
149 | return -EFAULT; |
150 | if (c == 'V') | |
151 | expect_close = 42; | |
152 | } | |
153 | ||
154 | return len; | |
155 | } | |
156 | ||
157 | return 0; | |
158 | } | |
159 | ||
9b748ed0 AC |
160 | static long scx200_wdt_ioctl(struct file *file, unsigned int cmd, |
161 | unsigned long arg) | |
1da177e4 LT |
162 | { |
163 | void __user *argp = (void __user *)arg; | |
164 | int __user *p = argp; | |
9b748ed0 | 165 | static const struct watchdog_info ident = { |
1da177e4 LT |
166 | .identity = "NatSemi SCx200 Watchdog", |
167 | .firmware_version = 1, | |
e73a7802 WVS |
168 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | |
169 | WDIOF_MAGICCLOSE, | |
1da177e4 LT |
170 | }; |
171 | int new_margin; | |
172 | ||
173 | switch (cmd) { | |
1da177e4 | 174 | case WDIOC_GETSUPPORT: |
9b748ed0 | 175 | if (copy_to_user(argp, &ident, sizeof(ident))) |
1da177e4 LT |
176 | 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; | |
0c06090c WVS |
198 | default: |
199 | return -ENOTTY; | |
1da177e4 LT |
200 | } |
201 | } | |
202 | ||
62322d25 | 203 | static const struct file_operations scx200_wdt_fops = { |
9b748ed0 AC |
204 | .owner = THIS_MODULE, |
205 | .llseek = no_llseek, | |
206 | .write = scx200_wdt_write, | |
207 | .unlocked_ioctl = scx200_wdt_ioctl, | |
208 | .open = scx200_wdt_open, | |
1da177e4 LT |
209 | .release = scx200_wdt_release, |
210 | }; | |
211 | ||
212 | static struct miscdevice scx200_wdt_miscdev = { | |
213 | .minor = WATCHDOG_MINOR, | |
9b748ed0 AC |
214 | .name = "watchdog", |
215 | .fops = &scx200_wdt_fops, | |
1da177e4 LT |
216 | }; |
217 | ||
218 | static 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 | ||
c6cb13ae | 238 | r = register_reboot_notifier(&scx200_wdt_notifier); |
1da177e4 | 239 | if (r) { |
c6cb13ae | 240 | printk(KERN_ERR NAME ": unable to register reboot notifier"); |
1da177e4 LT |
241 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
242 | SCx200_WDT_SIZE); | |
243 | return r; | |
244 | } | |
245 | ||
c6cb13ae | 246 | r = misc_register(&scx200_wdt_miscdev); |
1da177e4 | 247 | if (r) { |
c6cb13ae | 248 | unregister_reboot_notifier(&scx200_wdt_notifier); |
1da177e4 LT |
249 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
250 | SCx200_WDT_SIZE); | |
251 | return r; | |
252 | } | |
253 | ||
254 | return 0; | |
255 | } | |
256 | ||
257 | static void __exit scx200_wdt_cleanup(void) | |
258 | { | |
1da177e4 | 259 | misc_deregister(&scx200_wdt_miscdev); |
c6cb13ae | 260 | unregister_reboot_notifier(&scx200_wdt_notifier); |
1da177e4 LT |
261 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
262 | SCx200_WDT_SIZE); | |
263 | } | |
264 | ||
265 | module_init(scx200_wdt_init); | |
266 | module_exit(scx200_wdt_cleanup); | |
267 | ||
268 | /* | |
269 | Local variables: | |
9b748ed0 AC |
270 | compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules" |
271 | c-basic-offset: 8 | |
1da177e4 LT |
272 | End: |
273 | */ |