[PATCH 13/13] drivers/watchdog: use USB API functions rather than constants
[linux-2.6.git] / drivers / watchdog / ep93xx_wdt.c
1 /*
2  * Watchdog driver for Cirrus Logic EP93xx family of devices.
3  *
4  * Copyright (c) 2004 Ray Lehtiniemi
5  * Copyright (c) 2006 Tower Technologies
6  * Based on ep93xx driver, bits from alim7101_wdt.c
7  *
8  * Authors: Ray Lehtiniemi <rayl@mail.com>,
9  *      Alessandro Zummo <a.zummo@towertech.it>
10  *
11  * This file is licensed under the terms of the GNU General Public
12  * License version 2. This program is licensed "as is" without any
13  * warranty of any kind, whether express or implied.
14  *
15  * This watchdog fires after 250msec, which is a too short interval
16  * for us to rely on the user space daemon alone. So we ping the
17  * wdt each ~200msec and eventually stop doing it if the user space
18  * daemon dies.
19  *
20  * TODO:
21  *
22  *      - Test last reset from watchdog status
23  *      - Add a few missing ioctls
24  */
25
26 #include <linux/module.h>
27 #include <linux/fs.h>
28 #include <linux/miscdevice.h>
29 #include <linux/watchdog.h>
30 #include <linux/timer.h>
31 #include <linux/uaccess.h>
32 #include <mach/hardware.h>
33
34 #define WDT_VERSION     "0.3"
35 #define PFX             "ep93xx_wdt: "
36
37 /* default timeout (secs) */
38 #define WDT_TIMEOUT 30
39
40 static int nowayout = WATCHDOG_NOWAYOUT;
41 static int timeout = WDT_TIMEOUT;
42
43 static struct timer_list timer;
44 static unsigned long next_heartbeat;
45 static unsigned long wdt_status;
46 static unsigned long boot_status;
47
48 #define WDT_IN_USE              0
49 #define WDT_OK_TO_CLOSE         1
50
51 #define EP93XX_WDT_REG(x)       (EP93XX_WATCHDOG_BASE + (x))
52 #define EP93XX_WDT_WATCHDOG     EP93XX_WDT_REG(0x00)
53 #define EP93XX_WDT_WDSTATUS     EP93XX_WDT_REG(0x04)
54
55 /* reset the wdt every ~200ms */
56 #define WDT_INTERVAL (HZ/5)
57
58 static void wdt_enable(void)
59 {
60         __raw_writew(0xaaaa, EP93XX_WDT_WATCHDOG);
61 }
62
63 static void wdt_disable(void)
64 {
65         __raw_writew(0xaa55, EP93XX_WDT_WATCHDOG);
66 }
67
68 static inline void wdt_ping(void)
69 {
70         __raw_writew(0x5555, EP93XX_WDT_WATCHDOG);
71 }
72
73 static void wdt_startup(void)
74 {
75         next_heartbeat = jiffies + (timeout * HZ);
76
77         wdt_enable();
78         mod_timer(&timer, jiffies + WDT_INTERVAL);
79 }
80
81 static void wdt_shutdown(void)
82 {
83         del_timer_sync(&timer);
84         wdt_disable();
85 }
86
87 static void wdt_keepalive(void)
88 {
89         /* user land ping */
90         next_heartbeat = jiffies + (timeout * HZ);
91 }
92
93 static int ep93xx_wdt_open(struct inode *inode, struct file *file)
94 {
95         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
96                 return -EBUSY;
97
98         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
99
100         wdt_startup();
101
102         return nonseekable_open(inode, file);
103 }
104
105 static ssize_t
106 ep93xx_wdt_write(struct file *file, const char __user *data, size_t len,
107                  loff_t *ppos)
108 {
109         if (len) {
110                 if (!nowayout) {
111                         size_t i;
112
113                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
114
115                         for (i = 0; i != len; i++) {
116                                 char c;
117
118                                 if (get_user(c, data + i))
119                                         return -EFAULT;
120
121                                 if (c == 'V')
122                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
123                                 else
124                                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
125                         }
126                 }
127                 wdt_keepalive();
128         }
129
130         return len;
131 }
132
133 static struct watchdog_info ident = {
134         .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE,
135         .identity = "EP93xx Watchdog",
136 };
137
138 static long ep93xx_wdt_ioctl(struct file *file,
139                                         unsigned int cmd, unsigned long arg)
140 {
141         int ret = -ENOTTY;
142
143         switch (cmd) {
144         case WDIOC_GETSUPPORT:
145                 ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
146                                 sizeof(ident)) ? -EFAULT : 0;
147                 break;
148
149         case WDIOC_GETSTATUS:
150                 ret = put_user(0, (int __user *)arg);
151                 break;
152
153         case WDIOC_GETBOOTSTATUS:
154                 ret = put_user(boot_status, (int __user *)arg);
155                 break;
156
157         case WDIOC_KEEPALIVE:
158                 wdt_keepalive();
159                 ret = 0;
160                 break;
161
162         case WDIOC_GETTIMEOUT:
163                 /* actually, it is 0.250 seconds.... */
164                 ret = put_user(1, (int __user *)arg);
165                 break;
166         }
167         return ret;
168 }
169
170 static int ep93xx_wdt_release(struct inode *inode, struct file *file)
171 {
172         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
173                 wdt_shutdown();
174         else
175                 printk(KERN_CRIT PFX
176                         "Device closed unexpectedly - timer will not stop\n");
177
178         clear_bit(WDT_IN_USE, &wdt_status);
179         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
180
181         return 0;
182 }
183
184 static const struct file_operations ep93xx_wdt_fops = {
185         .owner          = THIS_MODULE,
186         .write          = ep93xx_wdt_write,
187         .unlocked_ioctl = ep93xx_wdt_ioctl,
188         .open           = ep93xx_wdt_open,
189         .release        = ep93xx_wdt_release,
190 };
191
192 static struct miscdevice ep93xx_wdt_miscdev = {
193         .minor          = WATCHDOG_MINOR,
194         .name           = "watchdog",
195         .fops           = &ep93xx_wdt_fops,
196 };
197
198 static void ep93xx_timer_ping(unsigned long data)
199 {
200         if (time_before(jiffies, next_heartbeat))
201                 wdt_ping();
202
203         /* Re-set the timer interval */
204         mod_timer(&timer, jiffies + WDT_INTERVAL);
205 }
206
207 static int __init ep93xx_wdt_init(void)
208 {
209         int err;
210
211         err = misc_register(&ep93xx_wdt_miscdev);
212
213         boot_status = __raw_readl(EP93XX_WDT_WATCHDOG) & 0x01 ? 1 : 0;
214
215         printk(KERN_INFO PFX "EP93XX watchdog, driver version "
216                 WDT_VERSION "%s\n",
217                 (__raw_readl(EP93XX_WDT_WATCHDOG) & 0x08)
218                 ? " (nCS1 disable detected)" : "");
219
220         if (timeout < 1 || timeout > 3600) {
221                 timeout = WDT_TIMEOUT;
222                 printk(KERN_INFO PFX
223                         "timeout value must be 1<=x<=3600, using %d\n",
224                         timeout);
225         }
226
227         setup_timer(&timer, ep93xx_timer_ping, 1);
228         return err;
229 }
230
231 static void __exit ep93xx_wdt_exit(void)
232 {
233         wdt_shutdown();
234         misc_deregister(&ep93xx_wdt_miscdev);
235 }
236
237 module_init(ep93xx_wdt_init);
238 module_exit(ep93xx_wdt_exit);
239
240 module_param(nowayout, int, 0);
241 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
242
243 module_param(timeout, int, 0);
244 MODULE_PARM_DESC(timeout,
245         "Watchdog timeout in seconds. (1<=timeout<=3600, default="
246                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
247
248 MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>,"
249                 "Alessandro Zummo <a.zummo@towertech.it>");
250 MODULE_DESCRIPTION("EP93xx Watchdog");
251 MODULE_LICENSE("GPL");
252 MODULE_VERSION(WDT_VERSION);
253 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);