switch lookup_mnt()
[linux-2.6.git] / drivers / watchdog / ks8695_wdt.c
1 /*
2  * Watchdog driver for Kendin/Micrel KS8695.
3  *
4  * (C) 2007 Andrew Victor
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
11 #include <linux/bitops.h>
12 #include <linux/errno.h>
13 #include <linux/fs.h>
14 #include <linux/init.h>
15 #include <linux/kernel.h>
16 #include <linux/miscdevice.h>
17 #include <linux/module.h>
18 #include <linux/moduleparam.h>
19 #include <linux/platform_device.h>
20 #include <linux/types.h>
21 #include <linux/watchdog.h>
22 #include <linux/io.h>
23 #include <linux/uaccess.h>
24 #include <mach/timex.h>
25 #include <mach/regs-timer.h>
26
27 #define WDT_DEFAULT_TIME        5       /* seconds */
28 #define WDT_MAX_TIME            171     /* seconds */
29
30 static int wdt_time = WDT_DEFAULT_TIME;
31 static int nowayout = WATCHDOG_NOWAYOUT;
32
33 module_param(wdt_time, int, 0);
34 MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
35                                         __MODULE_STRING(WDT_DEFAULT_TIME) ")");
36
37 #ifdef CONFIG_WATCHDOG_NOWAYOUT
38 module_param(nowayout, int, 0);
39 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
40                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
41 #endif
42
43
44 static unsigned long ks8695wdt_busy;
45 static spinlock_t ks8695_lock;
46
47 /* ......................................................................... */
48
49 /*
50  * Disable the watchdog.
51  */
52 static inline void ks8695_wdt_stop(void)
53 {
54         unsigned long tmcon;
55
56         spin_lock(&ks8695_lock);
57         /* disable timer0 */
58         tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
59         __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
60         spin_unlock(&ks8695_lock);
61 }
62
63 /*
64  * Enable and reset the watchdog.
65  */
66 static inline void ks8695_wdt_start(void)
67 {
68         unsigned long tmcon;
69         unsigned long tval = wdt_time * CLOCK_TICK_RATE;
70
71         spin_lock(&ks8695_lock);
72         /* disable timer0 */
73         tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
74         __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
75
76         /* program timer0 */
77         __raw_writel(tval | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);
78
79         /* re-enable timer0 */
80         tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
81         __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
82         spin_unlock(&ks8695_lock);
83 }
84
85 /*
86  * Reload the watchdog timer.  (ie, pat the watchdog)
87  */
88 static inline void ks8695_wdt_reload(void)
89 {
90         unsigned long tmcon;
91
92         spin_lock(&ks8695_lock);
93         /* disable, then re-enable timer0 */
94         tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
95         __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
96         __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
97         spin_unlock(&ks8695_lock);
98 }
99
100 /*
101  * Change the watchdog time interval.
102  */
103 static int ks8695_wdt_settimeout(int new_time)
104 {
105         /*
106          * All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz
107          *
108          * Since WDV is a 16-bit counter, the maximum period is
109          * 65536 / 0.256 = 256 seconds.
110          */
111         if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
112                 return -EINVAL;
113
114         /* Set new watchdog time. It will be used when
115            ks8695_wdt_start() is called. */
116         wdt_time = new_time;
117         return 0;
118 }
119
120 /* ......................................................................... */
121
122 /*
123  * Watchdog device is opened, and watchdog starts running.
124  */
125 static int ks8695_wdt_open(struct inode *inode, struct file *file)
126 {
127         if (test_and_set_bit(0, &ks8695wdt_busy))
128                 return -EBUSY;
129
130         ks8695_wdt_start();
131         return nonseekable_open(inode, file);
132 }
133
134 /*
135  * Close the watchdog device.
136  * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
137  *  disabled.
138  */
139 static int ks8695_wdt_close(struct inode *inode, struct file *file)
140 {
141         /* Disable the watchdog when file is closed */
142         if (!nowayout)
143                 ks8695_wdt_stop();
144         clear_bit(0, &ks8695wdt_busy);
145         return 0;
146 }
147
148 static struct watchdog_info ks8695_wdt_info = {
149         .identity       = "ks8695 watchdog",
150         .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
151 };
152
153 /*
154  * Handle commands from user-space.
155  */
156 static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd,
157                                                         unsigned long arg)
158 {
159         void __user *argp = (void __user *)arg;
160         int __user *p = argp;
161         int new_value;
162
163         switch (cmd) {
164         case WDIOC_GETSUPPORT:
165                 return copy_to_user(argp, &ks8695_wdt_info,
166                                         sizeof(ks8695_wdt_info)) ? -EFAULT : 0;
167         case WDIOC_GETSTATUS:
168         case WDIOC_GETBOOTSTATUS:
169                 return put_user(0, p);
170         case WDIOC_SETOPTIONS:
171                 if (get_user(new_value, p))
172                         return -EFAULT;
173                 if (new_value & WDIOS_DISABLECARD)
174                         ks8695_wdt_stop();
175                 if (new_value & WDIOS_ENABLECARD)
176                         ks8695_wdt_start();
177                 return 0;
178         case WDIOC_KEEPALIVE:
179                 ks8695_wdt_reload();    /* pat the watchdog */
180                 return 0;
181         case WDIOC_SETTIMEOUT:
182                 if (get_user(new_value, p))
183                         return -EFAULT;
184                 if (ks8695_wdt_settimeout(new_value))
185                         return -EINVAL;
186                 /* Enable new time value */
187                 ks8695_wdt_start();
188                 /* Return current value */
189                 return put_user(wdt_time, p);
190         case WDIOC_GETTIMEOUT:
191                 return put_user(wdt_time, p);
192         default:
193                 return -ENOTTY;
194         }
195 }
196
197 /*
198  * Pat the watchdog whenever device is written to.
199  */
200 static ssize_t ks8695_wdt_write(struct file *file, const char *data,
201                                                 size_t len, loff_t *ppos)
202 {
203         ks8695_wdt_reload();            /* pat the watchdog */
204         return len;
205 }
206
207 /* ......................................................................... */
208
209 static const struct file_operations ks8695wdt_fops = {
210         .owner          = THIS_MODULE,
211         .llseek         = no_llseek,
212         .unlocked_ioctl = ks8695_wdt_ioctl,
213         .open           = ks8695_wdt_open,
214         .release        = ks8695_wdt_close,
215         .write          = ks8695_wdt_write,
216 };
217
218 static struct miscdevice ks8695wdt_miscdev = {
219         .minor          = WATCHDOG_MINOR,
220         .name           = "watchdog",
221         .fops           = &ks8695wdt_fops,
222 };
223
224 static int __devinit ks8695wdt_probe(struct platform_device *pdev)
225 {
226         int res;
227
228         if (ks8695wdt_miscdev.parent)
229                 return -EBUSY;
230         ks8695wdt_miscdev.parent = &pdev->dev;
231
232         res = misc_register(&ks8695wdt_miscdev);
233         if (res)
234                 return res;
235
236         printk(KERN_INFO "KS8695 Watchdog Timer enabled (%d seconds%s)\n",
237                                 wdt_time, nowayout ? ", nowayout" : "");
238         return 0;
239 }
240
241 static int __devexit ks8695wdt_remove(struct platform_device *pdev)
242 {
243         int res;
244
245         res = misc_deregister(&ks8695wdt_miscdev);
246         if (!res)
247                 ks8695wdt_miscdev.parent = NULL;
248
249         return res;
250 }
251
252 static void ks8695wdt_shutdown(struct platform_device *pdev)
253 {
254         ks8695_wdt_stop();
255 }
256
257 #ifdef CONFIG_PM
258
259 static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message)
260 {
261         ks8695_wdt_stop();
262         return 0;
263 }
264
265 static int ks8695wdt_resume(struct platform_device *pdev)
266 {
267         if (ks8695wdt_busy)
268                 ks8695_wdt_start();
269         return 0;
270 }
271
272 #else
273 #define ks8695wdt_suspend NULL
274 #define ks8695wdt_resume        NULL
275 #endif
276
277 static struct platform_driver ks8695wdt_driver = {
278         .probe          = ks8695wdt_probe,
279         .remove         = __devexit_p(ks8695wdt_remove),
280         .shutdown       = ks8695wdt_shutdown,
281         .suspend        = ks8695wdt_suspend,
282         .resume         = ks8695wdt_resume,
283         .driver         = {
284                 .name   = "ks8695_wdt",
285                 .owner  = THIS_MODULE,
286         },
287 };
288
289 static int __init ks8695_wdt_init(void)
290 {
291         spin_lock_init(&ks8695_lock);
292         /* Check that the heartbeat value is within range;
293            if not reset to the default */
294         if (ks8695_wdt_settimeout(wdt_time)) {
295                 ks8695_wdt_settimeout(WDT_DEFAULT_TIME);
296                 pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i, using %d\n",
297                                                         wdt_time, WDT_MAX_TIME);
298         }
299         return platform_driver_register(&ks8695wdt_driver);
300 }
301
302 static void __exit ks8695_wdt_exit(void)
303 {
304         platform_driver_unregister(&ks8695wdt_driver);
305 }
306
307 module_init(ks8695_wdt_init);
308 module_exit(ks8695_wdt_exit);
309
310 MODULE_AUTHOR("Andrew Victor");
311 MODULE_DESCRIPTION("Watchdog driver for KS8695");
312 MODULE_LICENSE("GPL");
313 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
314 MODULE_ALIAS("platform:ks8695_wdt");