[WATCHDOG] more coding style clean-up's
[linux-2.6.git] / drivers / watchdog / geodewdt.c
1 /* Watchdog timer for the Geode GX/LX with the CS5535/CS5536 companion chip
2  *
3  * Copyright (C) 2006-2007, Advanced Micro Devices, Inc.
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU General Public License
7  * as published by the Free Software Foundation; either version
8  * 2 of the License, or (at your option) any later version.
9  */
10
11
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/types.h>
15 #include <linux/miscdevice.h>
16 #include <linux/watchdog.h>
17 #include <linux/fs.h>
18 #include <linux/platform_device.h>
19 #include <linux/reboot.h>
20 #include <linux/uaccess.h>
21
22 #include <asm/geode.h>
23
24 #define GEODEWDT_HZ 500
25 #define GEODEWDT_SCALE 6
26 #define GEODEWDT_MAX_SECONDS 131
27
28 #define WDT_FLAGS_OPEN 1
29 #define WDT_FLAGS_ORPHAN 2
30
31 #define DRV_NAME "geodewdt"
32 #define WATCHDOG_NAME "Geode GX/LX WDT"
33 #define WATCHDOG_TIMEOUT 60
34
35 static int timeout = WATCHDOG_TIMEOUT;
36 module_param(timeout, int, 0);
37 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=131, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
38
39 static int nowayout = WATCHDOG_NOWAYOUT;
40 module_param(nowayout, int, 0);
41 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
42
43 static struct platform_device *geodewdt_platform_device;
44 static unsigned long wdt_flags;
45 static int wdt_timer;
46 static int safe_close;
47
48 static void geodewdt_ping(void)
49 {
50         /* Stop the counter */
51         geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
52
53         /* Reset the counter */
54         geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
55
56         /* Enable the counter */
57         geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
58 }
59
60 static void geodewdt_disable(void)
61 {
62         geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
63         geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
64 }
65
66 static int geodewdt_set_heartbeat(int val)
67 {
68         if (val < 1 || val > GEODEWDT_MAX_SECONDS)
69                 return -EINVAL;
70
71         geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
72         geode_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ);
73         geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
74         geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
75
76         timeout = val;
77         return 0;
78 }
79
80 static int geodewdt_open(struct inode *inode, struct file *file)
81 {
82         if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags))
83                 return -EBUSY;
84
85         if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags))
86                 __module_get(THIS_MODULE);
87
88         geodewdt_ping();
89         return nonseekable_open(inode, file);
90 }
91
92 static int geodewdt_release(struct inode *inode, struct file *file)
93 {
94         if (safe_close) {
95                 geodewdt_disable();
96                 module_put(THIS_MODULE);
97         } else {
98                 printk(KERN_CRIT "Unexpected close - watchdog is not stopping.\n");
99                 geodewdt_ping();
100
101                 set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
102         }
103
104         clear_bit(WDT_FLAGS_OPEN, &wdt_flags);
105         safe_close = 0;
106         return 0;
107 }
108
109 static ssize_t geodewdt_write(struct file *file, const char __user *data,
110                                 size_t len, loff_t *ppos)
111 {
112         if (len) {
113                 if (!nowayout) {
114                         size_t i;
115                         safe_close = 0;
116
117                         for (i = 0; i != len; i++) {
118                                 char c;
119
120                                 if (get_user(c, data + i))
121                                         return -EFAULT;
122
123                                 if (c == 'V')
124                                         safe_close = 1;
125                         }
126                 }
127
128                 geodewdt_ping();
129         }
130         return len;
131 }
132
133 static int geodewdt_ioctl(struct inode *inode, struct file *file,
134                                 unsigned int cmd, unsigned long arg)
135 {
136         void __user *argp = (void __user *)arg;
137         int __user *p = argp;
138         int interval;
139
140         static struct watchdog_info ident = {
141                 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
142                 | WDIOF_MAGICCLOSE,
143                 .firmware_version =     1,
144                 .identity =             WATCHDOG_NAME,
145         };
146
147         switch (cmd) {
148         case WDIOC_GETSUPPORT:
149                 return copy_to_user(argp, &ident,
150                                     sizeof(ident)) ? -EFAULT : 0;
151                 break;
152
153         case WDIOC_GETSTATUS:
154         case WDIOC_GETBOOTSTATUS:
155                 return put_user(0, p);
156
157         case WDIOC_SETOPTIONS:
158         {
159                 int options, ret = -EINVAL;
160
161                 if (get_user(options, p))
162                         return -EFAULT;
163
164                 if (options & WDIOS_DISABLECARD) {
165                         geodewdt_disable();
166                         ret = 0;
167                 }
168
169                 if (options & WDIOS_ENABLECARD) {
170                         geodewdt_ping();
171                         ret = 0;
172                 }
173
174                 return ret;
175         }
176         case WDIOC_KEEPALIVE:
177                 geodewdt_ping();
178                 return 0;
179
180         case WDIOC_SETTIMEOUT:
181                 if (get_user(interval, p))
182                         return -EFAULT;
183
184                 if (geodewdt_set_heartbeat(interval))
185                         return -EINVAL;
186         /* Fall through */
187         case WDIOC_GETTIMEOUT:
188                 return put_user(timeout, p);
189
190         default:
191                 return -ENOTTY;
192         }
193
194         return 0;
195 }
196
197 static const struct file_operations geodewdt_fops = {
198         .owner          = THIS_MODULE,
199         .llseek         = no_llseek,
200         .write          = geodewdt_write,
201         .ioctl          = geodewdt_ioctl,
202         .open           = geodewdt_open,
203         .release        = geodewdt_release,
204 };
205
206 static struct miscdevice geodewdt_miscdev = {
207         .minor = WATCHDOG_MINOR,
208         .name = "watchdog",
209         .fops = &geodewdt_fops,
210 };
211
212 static int __devinit geodewdt_probe(struct platform_device *dev)
213 {
214         int ret, timer;
215
216         timer = geode_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING);
217
218         if (timer == -1) {
219                 printk(KERN_ERR "geodewdt:  No timers were available\n");
220                 return -ENODEV;
221         }
222
223         wdt_timer = timer;
224
225         /* Set up the timer */
226
227         geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
228                           GEODEWDT_SCALE | (3 << 8));
229
230         /* Set up comparator 2 to reset when the event fires */
231         geode_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1);
232
233         /* Set up the initial timeout */
234
235         geode_mfgpt_write(wdt_timer, MFGPT_REG_CMP2,
236                 timeout * GEODEWDT_HZ);
237
238         ret = misc_register(&geodewdt_miscdev);
239
240         return ret;
241 }
242
243 static int __devexit geodewdt_remove(struct platform_device *dev)
244 {
245         misc_deregister(&geodewdt_miscdev);
246         return 0;
247 }
248
249 static void geodewdt_shutdown(struct platform_device *dev)
250 {
251         geodewdt_disable();
252 }
253
254 static struct platform_driver geodewdt_driver = {
255         .probe          = geodewdt_probe,
256         .remove         = __devexit_p(geodewdt_remove),
257         .shutdown       = geodewdt_shutdown,
258         .driver         = {
259                 .owner  = THIS_MODULE,
260                 .name   = DRV_NAME,
261         },
262 };
263
264 static int __init geodewdt_init(void)
265 {
266         int ret;
267
268         ret = platform_driver_register(&geodewdt_driver);
269         if (ret)
270                 return ret;
271
272         geodewdt_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0);
273         if (IS_ERR(geodewdt_platform_device)) {
274                 ret = PTR_ERR(geodewdt_platform_device);
275                 goto err;
276         }
277
278         return 0;
279 err:
280         platform_driver_unregister(&geodewdt_driver);
281         return ret;
282 }
283
284 static void __exit geodewdt_exit(void)
285 {
286         platform_device_unregister(geodewdt_platform_device);
287         platform_driver_unregister(&geodewdt_driver);
288 }
289
290 module_init(geodewdt_init);
291 module_exit(geodewdt_exit);
292
293 MODULE_AUTHOR("Advanced Micro Devices, Inc");
294 MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver");
295 MODULE_LICENSE("GPL");
296 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);