Commit | Line | Data |
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c4c28335 GG |
1 | /* |
2 | * NANO7240 SBC Watchdog device driver | |
3 | * | |
4 | * Based on w83877f.c by Scott Jennings, | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation; | |
9 | * | |
10 | * Software distributed under the License is distributed on an "AS IS" | |
11 | * basis, WITHOUT WARRANTY OF ANY KIND, either express or | |
12 | * implied. See the License for the specific language governing | |
13 | * rights and limitations under the License. | |
14 | * | |
15 | * (c) Copyright 2007 Gilles GIGAN <gilles.gigan@jcu.edu.au> | |
16 | * | |
17 | */ | |
18 | ||
19 | #include <linux/fs.h> | |
20 | #include <linux/init.h> | |
21 | #include <linux/ioport.h> | |
22 | #include <linux/jiffies.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/moduleparam.h> | |
25 | #include <linux/miscdevice.h> | |
26 | #include <linux/notifier.h> | |
27 | #include <linux/reboot.h> | |
28 | #include <linux/types.h> | |
29 | #include <linux/watchdog.h> | |
619a8a2b AC |
30 | #include <linux/io.h> |
31 | #include <linux/uaccess.h> | |
c4c28335 | 32 | #include <asm/atomic.h> |
c4c28335 | 33 | #include <asm/system.h> |
c4c28335 GG |
34 | |
35 | #define SBC7240_PREFIX "sbc7240_wdt: " | |
36 | ||
37 | #define SBC7240_ENABLE_PORT 0x443 | |
38 | #define SBC7240_DISABLE_PORT 0x043 | |
39 | #define SBC7240_SET_TIMEOUT_PORT SBC7240_ENABLE_PORT | |
40 | #define SBC7240_MAGIC_CHAR 'V' | |
41 | ||
42 | #define SBC7240_TIMEOUT 30 | |
43 | #define SBC7240_MAX_TIMEOUT 255 | |
44 | static int timeout = SBC7240_TIMEOUT; /* in seconds */ | |
45 | module_param(timeout, int, 0); | |
46 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=" | |
47 | __MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default=" | |
48 | __MODULE_STRING(SBC7240_TIMEOUT) ")"); | |
49 | ||
50 | static int nowayout = WATCHDOG_NOWAYOUT; | |
51 | module_param(nowayout, int, 0); | |
52 | MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file"); | |
53 | ||
54 | #define SBC7240_OPEN_STATUS_BIT 0 | |
55 | #define SBC7240_ENABLED_STATUS_BIT 1 | |
56 | #define SBC7240_EXPECT_CLOSE_STATUS_BIT 2 | |
57 | static unsigned long wdt_status; | |
58 | ||
59 | /* | |
60 | * Utility routines | |
61 | */ | |
62 | ||
63 | static void wdt_disable(void) | |
64 | { | |
65 | /* disable the watchdog */ | |
66 | if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) { | |
67 | inb_p(SBC7240_DISABLE_PORT); | |
68 | printk(KERN_INFO SBC7240_PREFIX | |
69 | "Watchdog timer is now disabled.\n"); | |
70 | } | |
71 | } | |
72 | ||
73 | static void wdt_enable(void) | |
74 | { | |
75 | /* enable the watchdog */ | |
76 | if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) { | |
77 | inb_p(SBC7240_ENABLE_PORT); | |
78 | printk(KERN_INFO SBC7240_PREFIX | |
79 | "Watchdog timer is now enabled.\n"); | |
80 | } | |
81 | } | |
82 | ||
83 | static int wdt_set_timeout(int t) | |
84 | { | |
85 | if (t < 1 || t > SBC7240_MAX_TIMEOUT) { | |
86 | printk(KERN_ERR SBC7240_PREFIX | |
87 | "timeout value must be 1<=x<=%d\n", | |
88 | SBC7240_MAX_TIMEOUT); | |
89 | return -1; | |
90 | } | |
91 | /* set the timeout */ | |
92 | outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT); | |
93 | timeout = t; | |
94 | printk(KERN_INFO SBC7240_PREFIX "timeout set to %d seconds\n", t); | |
95 | return 0; | |
96 | } | |
97 | ||
98 | /* Whack the dog */ | |
99 | static inline void wdt_keepalive(void) | |
100 | { | |
101 | if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) | |
102 | inb_p(SBC7240_ENABLE_PORT); | |
103 | } | |
104 | ||
105 | /* | |
106 | * /dev/watchdog handling | |
107 | */ | |
108 | static ssize_t fop_write(struct file *file, const char __user *buf, | |
109 | size_t count, loff_t *ppos) | |
110 | { | |
111 | size_t i; | |
112 | char c; | |
113 | ||
114 | if (count) { | |
115 | if (!nowayout) { | |
116 | clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, | |
117 | &wdt_status); | |
118 | ||
119 | /* is there a magic char ? */ | |
120 | for (i = 0; i != count; i++) { | |
121 | if (get_user(c, buf + i)) | |
122 | return -EFAULT; | |
123 | if (c == SBC7240_MAGIC_CHAR) { | |
124 | set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, | |
125 | &wdt_status); | |
126 | break; | |
127 | } | |
128 | } | |
129 | } | |
130 | ||
131 | wdt_keepalive(); | |
132 | } | |
133 | ||
134 | return count; | |
135 | } | |
136 | ||
137 | static int fop_open(struct inode *inode, struct file *file) | |
138 | { | |
139 | if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status)) | |
140 | return -EBUSY; | |
141 | ||
142 | wdt_enable(); | |
143 | ||
144 | return nonseekable_open(inode, file); | |
145 | } | |
146 | ||
147 | static int fop_close(struct inode *inode, struct file *file) | |
148 | { | |
149 | if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status) | |
150 | || !nowayout) { | |
151 | wdt_disable(); | |
152 | } else { | |
153 | printk(KERN_CRIT SBC7240_PREFIX | |
154 | "Unexpected close, not stopping watchdog!\n"); | |
155 | wdt_keepalive(); | |
156 | } | |
157 | ||
158 | clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status); | |
159 | return 0; | |
160 | } | |
161 | ||
619a8a2b | 162 | static const struct watchdog_info ident = { |
c4c28335 GG |
163 | .options = WDIOF_KEEPALIVEPING| |
164 | WDIOF_SETTIMEOUT| | |
165 | WDIOF_MAGICCLOSE, | |
166 | .firmware_version = 1, | |
167 | .identity = "SBC7240", | |
168 | }; | |
169 | ||
170 | ||
619a8a2b | 171 | static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
c4c28335 GG |
172 | { |
173 | switch (cmd) { | |
174 | case WDIOC_GETSUPPORT: | |
619a8a2b AC |
175 | return copy_to_user((void __user *)arg, &ident, sizeof(ident)) |
176 | ? -EFAULT : 0; | |
c4c28335 GG |
177 | case WDIOC_GETSTATUS: |
178 | case WDIOC_GETBOOTSTATUS: | |
179 | return put_user(0, (int __user *)arg); | |
0c06090c WVS |
180 | case WDIOC_SETOPTIONS: |
181 | { | |
182 | int options; | |
183 | int retval = -EINVAL; | |
c4c28335 | 184 | |
0c06090c WVS |
185 | if (get_user(options, (int __user *)arg)) |
186 | return -EFAULT; | |
c4c28335 | 187 | |
0c06090c WVS |
188 | if (options & WDIOS_DISABLECARD) { |
189 | wdt_disable(); | |
190 | retval = 0; | |
191 | } | |
c4c28335 | 192 | |
0c06090c WVS |
193 | if (options & WDIOS_ENABLECARD) { |
194 | wdt_enable(); | |
195 | retval = 0; | |
c4c28335 | 196 | } |
c4c28335 | 197 | |
0c06090c WVS |
198 | return retval; |
199 | } | |
200 | case WDIOC_KEEPALIVE: | |
201 | wdt_keepalive(); | |
202 | return 0; | |
203 | case WDIOC_SETTIMEOUT: | |
204 | { | |
205 | int new_timeout; | |
c4c28335 | 206 | |
0c06090c WVS |
207 | if (get_user(new_timeout, (int __user *)arg)) |
208 | return -EFAULT; | |
c4c28335 | 209 | |
0c06090c WVS |
210 | if (wdt_set_timeout(new_timeout)) |
211 | return -EINVAL; | |
212 | ||
213 | /* Fall through */ | |
214 | } | |
c4c28335 GG |
215 | case WDIOC_GETTIMEOUT: |
216 | return put_user(timeout, (int __user *)arg); | |
217 | default: | |
218 | return -ENOTTY; | |
219 | } | |
220 | } | |
221 | ||
222 | static const struct file_operations wdt_fops = { | |
223 | .owner = THIS_MODULE, | |
224 | .llseek = no_llseek, | |
225 | .write = fop_write, | |
226 | .open = fop_open, | |
227 | .release = fop_close, | |
619a8a2b | 228 | .unlocked_ioctl = fop_ioctl, |
c4c28335 GG |
229 | }; |
230 | ||
231 | static struct miscdevice wdt_miscdev = { | |
232 | .minor = WATCHDOG_MINOR, | |
233 | .name = "watchdog", | |
234 | .fops = &wdt_fops, | |
235 | }; | |
236 | ||
237 | /* | |
238 | * Notifier for system down | |
239 | */ | |
240 | ||
241 | static int wdt_notify_sys(struct notifier_block *this, unsigned long code, | |
242 | void *unused) | |
243 | { | |
244 | if (code == SYS_DOWN || code == SYS_HALT) | |
245 | wdt_disable(); | |
246 | return NOTIFY_DONE; | |
247 | } | |
248 | ||
249 | static struct notifier_block wdt_notifier = { | |
250 | .notifier_call = wdt_notify_sys, | |
251 | }; | |
252 | ||
253 | static void __exit sbc7240_wdt_unload(void) | |
254 | { | |
255 | printk(KERN_INFO SBC7240_PREFIX "Removing watchdog\n"); | |
256 | misc_deregister(&wdt_miscdev); | |
257 | ||
258 | unregister_reboot_notifier(&wdt_notifier); | |
259 | release_region(SBC7240_ENABLE_PORT, 1); | |
260 | } | |
261 | ||
262 | static int __init sbc7240_wdt_init(void) | |
263 | { | |
264 | int rc = -EBUSY; | |
265 | ||
266 | if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) { | |
267 | printk(KERN_ERR SBC7240_PREFIX | |
268 | "I/O address 0x%04x already in use\n", | |
269 | SBC7240_ENABLE_PORT); | |
270 | rc = -EIO; | |
271 | goto err_out; | |
272 | } | |
273 | ||
274 | /* The IO port 0x043 used to disable the watchdog | |
275 | * is already claimed by the system timer, so we | |
276 | * cant request_region() it ...*/ | |
277 | ||
278 | if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) { | |
279 | timeout = SBC7240_TIMEOUT; | |
280 | printk(KERN_INFO SBC7240_PREFIX | |
281 | "timeout value must be 1<=x<=%d, using %d\n", | |
282 | SBC7240_MAX_TIMEOUT, timeout); | |
283 | } | |
284 | wdt_set_timeout(timeout); | |
285 | wdt_disable(); | |
286 | ||
287 | rc = register_reboot_notifier(&wdt_notifier); | |
288 | if (rc) { | |
289 | printk(KERN_ERR SBC7240_PREFIX | |
290 | "cannot register reboot notifier (err=%d)\n", rc); | |
291 | goto err_out_region; | |
292 | } | |
293 | ||
294 | rc = misc_register(&wdt_miscdev); | |
295 | if (rc) { | |
296 | printk(KERN_ERR SBC7240_PREFIX | |
297 | "cannot register miscdev on minor=%d (err=%d)\n", | |
298 | wdt_miscdev.minor, rc); | |
299 | goto err_out_reboot_notifier; | |
300 | } | |
301 | ||
302 | printk(KERN_INFO SBC7240_PREFIX | |
303 | "Watchdog driver for SBC7240 initialised (nowayout=%d)\n", | |
304 | nowayout); | |
305 | ||
306 | return 0; | |
307 | ||
308 | err_out_reboot_notifier: | |
309 | unregister_reboot_notifier(&wdt_notifier); | |
310 | err_out_region: | |
311 | release_region(SBC7240_ENABLE_PORT, 1); | |
312 | err_out: | |
313 | return rc; | |
314 | } | |
315 | ||
316 | module_init(sbc7240_wdt_init); | |
317 | module_exit(sbc7240_wdt_unload); | |
318 | ||
319 | MODULE_AUTHOR("Gilles Gigan"); | |
320 | MODULE_DESCRIPTION("Watchdog device driver for single board" | |
321 | " computers EPIC Nano 7240 from iEi"); | |
322 | MODULE_LICENSE("GPL"); | |
323 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
324 |