misc: tegra-throughput: fix fps reading
[linux-2.6.git] / drivers / watchdog / geodewdt.c
1 /* Watchdog timer for machines with the CS5535/CS5536 companion chip
2  *
3  * Copyright (C) 2006-2007, Advanced Micro Devices, Inc.
4  * Copyright (C) 2009  Andres Salomon <dilinger@collabora.co.uk>
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14 #include <linux/module.h>
15 #include <linux/moduleparam.h>
16 #include <linux/types.h>
17 #include <linux/miscdevice.h>
18 #include <linux/watchdog.h>
19 #include <linux/fs.h>
20 #include <linux/platform_device.h>
21 #include <linux/reboot.h>
22 #include <linux/uaccess.h>
23
24 #include <linux/cs5535.h>
25
26 #define GEODEWDT_HZ 500
27 #define GEODEWDT_SCALE 6
28 #define GEODEWDT_MAX_SECONDS 131
29
30 #define WDT_FLAGS_OPEN 1
31 #define WDT_FLAGS_ORPHAN 2
32
33 #define DRV_NAME "geodewdt"
34 #define WATCHDOG_NAME "Geode GX/LX WDT"
35 #define WATCHDOG_TIMEOUT 60
36
37 static int timeout = WATCHDOG_TIMEOUT;
38 module_param(timeout, int, 0);
39 MODULE_PARM_DESC(timeout,
40         "Watchdog timeout in seconds. 1<= timeout <=131, default="
41                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
42
43 static bool nowayout = WATCHDOG_NOWAYOUT;
44 module_param(nowayout, bool, 0);
45 MODULE_PARM_DESC(nowayout,
46         "Watchdog cannot be stopped once started (default="
47                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
48
49 static struct platform_device *geodewdt_platform_device;
50 static unsigned long wdt_flags;
51 static struct cs5535_mfgpt_timer *wdt_timer;
52 static int safe_close;
53
54 static void geodewdt_ping(void)
55 {
56         /* Stop the counter */
57         cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
58
59         /* Reset the counter */
60         cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
61
62         /* Enable the counter */
63         cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
64 }
65
66 static void geodewdt_disable(void)
67 {
68         cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
69         cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
70 }
71
72 static int geodewdt_set_heartbeat(int val)
73 {
74         if (val < 1 || val > GEODEWDT_MAX_SECONDS)
75                 return -EINVAL;
76
77         cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
78         cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ);
79         cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
80         cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
81
82         timeout = val;
83         return 0;
84 }
85
86 static int geodewdt_open(struct inode *inode, struct file *file)
87 {
88         if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags))
89                 return -EBUSY;
90
91         if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags))
92                 __module_get(THIS_MODULE);
93
94         geodewdt_ping();
95         return nonseekable_open(inode, file);
96 }
97
98 static int geodewdt_release(struct inode *inode, struct file *file)
99 {
100         if (safe_close) {
101                 geodewdt_disable();
102                 module_put(THIS_MODULE);
103         } else {
104                 pr_crit("Unexpected close - watchdog is not stopping\n");
105                 geodewdt_ping();
106
107                 set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
108         }
109
110         clear_bit(WDT_FLAGS_OPEN, &wdt_flags);
111         safe_close = 0;
112         return 0;
113 }
114
115 static ssize_t geodewdt_write(struct file *file, const char __user *data,
116                                 size_t len, loff_t *ppos)
117 {
118         if (len) {
119                 if (!nowayout) {
120                         size_t i;
121                         safe_close = 0;
122
123                         for (i = 0; i != len; i++) {
124                                 char c;
125
126                                 if (get_user(c, data + i))
127                                         return -EFAULT;
128
129                                 if (c == 'V')
130                                         safe_close = 1;
131                         }
132                 }
133
134                 geodewdt_ping();
135         }
136         return len;
137 }
138
139 static long geodewdt_ioctl(struct file *file, unsigned int cmd,
140                                 unsigned long arg)
141 {
142         void __user *argp = (void __user *)arg;
143         int __user *p = argp;
144         int interval;
145
146         static const struct watchdog_info ident = {
147                 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
148                 | WDIOF_MAGICCLOSE,
149                 .firmware_version =     1,
150                 .identity =             WATCHDOG_NAME,
151         };
152
153         switch (cmd) {
154         case WDIOC_GETSUPPORT:
155                 return copy_to_user(argp, &ident,
156                                     sizeof(ident)) ? -EFAULT : 0;
157                 break;
158
159         case WDIOC_GETSTATUS:
160         case WDIOC_GETBOOTSTATUS:
161                 return put_user(0, p);
162
163         case WDIOC_SETOPTIONS:
164         {
165                 int options, ret = -EINVAL;
166
167                 if (get_user(options, p))
168                         return -EFAULT;
169
170                 if (options & WDIOS_DISABLECARD) {
171                         geodewdt_disable();
172                         ret = 0;
173                 }
174
175                 if (options & WDIOS_ENABLECARD) {
176                         geodewdt_ping();
177                         ret = 0;
178                 }
179
180                 return ret;
181         }
182         case WDIOC_KEEPALIVE:
183                 geodewdt_ping();
184                 return 0;
185
186         case WDIOC_SETTIMEOUT:
187                 if (get_user(interval, p))
188                         return -EFAULT;
189
190                 if (geodewdt_set_heartbeat(interval))
191                         return -EINVAL;
192         /* Fall through */
193         case WDIOC_GETTIMEOUT:
194                 return put_user(timeout, p);
195
196         default:
197                 return -ENOTTY;
198         }
199
200         return 0;
201 }
202
203 static const struct file_operations geodewdt_fops = {
204         .owner          = THIS_MODULE,
205         .llseek         = no_llseek,
206         .write          = geodewdt_write,
207         .unlocked_ioctl = geodewdt_ioctl,
208         .open           = geodewdt_open,
209         .release        = geodewdt_release,
210 };
211
212 static struct miscdevice geodewdt_miscdev = {
213         .minor = WATCHDOG_MINOR,
214         .name = "watchdog",
215         .fops = &geodewdt_fops,
216 };
217
218 static int __devinit geodewdt_probe(struct platform_device *dev)
219 {
220         int ret;
221
222         wdt_timer = cs5535_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING);
223         if (!wdt_timer) {
224                 pr_err("No timers were available\n");
225                 return -ENODEV;
226         }
227
228         /* Set up the timer */
229
230         cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
231                           GEODEWDT_SCALE | (3 << 8));
232
233         /* Set up comparator 2 to reset when the event fires */
234         cs5535_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1);
235
236         /* Set up the initial timeout */
237
238         cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2,
239                 timeout * GEODEWDT_HZ);
240
241         ret = misc_register(&geodewdt_miscdev);
242
243         return ret;
244 }
245
246 static int __devexit geodewdt_remove(struct platform_device *dev)
247 {
248         misc_deregister(&geodewdt_miscdev);
249         return 0;
250 }
251
252 static void geodewdt_shutdown(struct platform_device *dev)
253 {
254         geodewdt_disable();
255 }
256
257 static struct platform_driver geodewdt_driver = {
258         .probe          = geodewdt_probe,
259         .remove         = __devexit_p(geodewdt_remove),
260         .shutdown       = geodewdt_shutdown,
261         .driver         = {
262                 .owner  = THIS_MODULE,
263                 .name   = DRV_NAME,
264         },
265 };
266
267 static int __init geodewdt_init(void)
268 {
269         int ret;
270
271         ret = platform_driver_register(&geodewdt_driver);
272         if (ret)
273                 return ret;
274
275         geodewdt_platform_device = platform_device_register_simple(DRV_NAME,
276                                                                 -1, NULL, 0);
277         if (IS_ERR(geodewdt_platform_device)) {
278                 ret = PTR_ERR(geodewdt_platform_device);
279                 goto err;
280         }
281
282         return 0;
283 err:
284         platform_driver_unregister(&geodewdt_driver);
285         return ret;
286 }
287
288 static void __exit geodewdt_exit(void)
289 {
290         platform_device_unregister(geodewdt_platform_device);
291         platform_driver_unregister(&geodewdt_driver);
292 }
293
294 module_init(geodewdt_init);
295 module_exit(geodewdt_exit);
296
297 MODULE_AUTHOR("Advanced Micro Devices, Inc");
298 MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver");
299 MODULE_LICENSE("GPL");
300 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);