parport_pc: show the detection of a 2 serial port ITE8874 chip
[linux-2.6.git] / drivers / watchdog / wdt285.c
1 /*
2  *      Intel 21285 watchdog driver
3  *      Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998
4  *
5  *      based on
6  *
7  *      SoftDog 0.05:   A Software Watchdog Device
8  *
9  *      (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
10  *                                              All Rights Reserved.
11  *
12  *      This program is free software; you can redistribute it and/or
13  *      modify it under the terms of the GNU General Public License
14  *      as published by the Free Software Foundation; either version
15  *      2 of the License, or (at your option) any later version.
16  *
17  */
18
19 #include <linux/module.h>
20 #include <linux/moduleparam.h>
21 #include <linux/types.h>
22 #include <linux/kernel.h>
23 #include <linux/fs.h>
24 #include <linux/mm.h>
25 #include <linux/miscdevice.h>
26 #include <linux/watchdog.h>
27 #include <linux/reboot.h>
28 #include <linux/init.h>
29 #include <linux/interrupt.h>
30 #include <linux/uaccess.h>
31 #include <linux/irq.h>
32 #include <mach/hardware.h>
33
34 #include <asm/mach-types.h>
35 #include <asm/hardware/dec21285.h>
36
37 /*
38  * Define this to stop the watchdog actually rebooting the machine.
39  */
40 #undef ONLY_TESTING
41
42 static unsigned int soft_margin = 60;           /* in seconds */
43 static unsigned int reload;
44 static unsigned long timer_alive;
45
46 #ifdef ONLY_TESTING
47 /*
48  *      If the timer expires..
49  */
50 static void watchdog_fire(int irq, void *dev_id)
51 {
52         printk(KERN_CRIT "Watchdog: Would Reboot.\n");
53         *CSR_TIMER4_CNTL = 0;
54         *CSR_TIMER4_CLR = 0;
55 }
56 #endif
57
58 /*
59  *      Refresh the timer.
60  */
61 static void watchdog_ping(void)
62 {
63         *CSR_TIMER4_LOAD = reload;
64 }
65
66 /*
67  *      Allow only one person to hold it open
68  */
69 static int watchdog_open(struct inode *inode, struct file *file)
70 {
71         int ret;
72
73         if (*CSR_SA110_CNTL & (1 << 13))
74                 return -EBUSY;
75
76         if (test_and_set_bit(1, &timer_alive))
77                 return -EBUSY;
78
79         reload = soft_margin * (mem_fclk_21285 / 256);
80
81         *CSR_TIMER4_CLR = 0;
82         watchdog_ping();
83         *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD
84                 | TIMER_CNTL_DIV256;
85
86 #ifdef ONLY_TESTING
87         ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL);
88         if (ret) {
89                 *CSR_TIMER4_CNTL = 0;
90                 clear_bit(1, &timer_alive);
91         }
92 #else
93         /*
94          * Setting this bit is irreversible; once enabled, there is
95          * no way to disable the watchdog.
96          */
97         *CSR_SA110_CNTL |= 1 << 13;
98
99         ret = 0;
100 #endif
101         nonseekable_open(inode, file);
102         return ret;
103 }
104
105 /*
106  *      Shut off the timer.
107  *      Note: if we really have enabled the watchdog, there
108  *      is no way to turn off.
109  */
110 static int watchdog_release(struct inode *inode, struct file *file)
111 {
112 #ifdef ONLY_TESTING
113         free_irq(IRQ_TIMER4, NULL);
114         clear_bit(1, &timer_alive);
115 #endif
116         return 0;
117 }
118
119 static ssize_t watchdog_write(struct file *file, const char __user *data,
120                               size_t len, loff_t *ppos)
121 {
122         /*
123          *      Refresh the timer.
124          */
125         if (len)
126                 watchdog_ping();
127
128         return len;
129 }
130
131 static const struct watchdog_info ident = {
132         .options        = WDIOF_SETTIMEOUT,
133         .identity       = "Footbridge Watchdog",
134 };
135
136 static long watchdog_ioctl(struct file *file, unsigned int cmd,
137                            unsigned long arg)
138 {
139         unsigned int new_margin;
140         int __user *int_arg = (int __user *)arg;
141         int ret = -ENOTTY;
142
143         switch (cmd) {
144         case WDIOC_GETSUPPORT:
145                 ret = 0;
146                 if (copy_to_user((void __user *)arg, &ident, sizeof(ident)))
147                         ret = -EFAULT;
148                 break;
149
150         case WDIOC_GETSTATUS:
151         case WDIOC_GETBOOTSTATUS:
152                 ret = put_user(0, int_arg);
153                 break;
154
155         case WDIOC_KEEPALIVE:
156                 watchdog_ping();
157                 ret = 0;
158                 break;
159
160         case WDIOC_SETTIMEOUT:
161                 ret = get_user(new_margin, int_arg);
162                 if (ret)
163                         break;
164
165                 /* Arbitrary, can't find the card's limits */
166                 if (new_margin < 0 || new_margin > 60) {
167                         ret = -EINVAL;
168                         break;
169                 }
170
171                 soft_margin = new_margin;
172                 reload = soft_margin * (mem_fclk_21285 / 256);
173                 watchdog_ping();
174                 /* Fall */
175         case WDIOC_GETTIMEOUT:
176                 ret = put_user(soft_margin, int_arg);
177                 break;
178         }
179         return ret;
180 }
181
182 static const struct file_operations watchdog_fops = {
183         .owner          = THIS_MODULE,
184         .llseek         = no_llseek,
185         .write          = watchdog_write,
186         .unlocked_ioctl = watchdog_ioctl,
187         .open           = watchdog_open,
188         .release        = watchdog_release,
189 };
190
191 static struct miscdevice watchdog_miscdev = {
192         .minor          = WATCHDOG_MINOR,
193         .name           = "watchdog",
194         .fops           = &watchdog_fops,
195 };
196
197 static int __init footbridge_watchdog_init(void)
198 {
199         int retval;
200
201         if (machine_is_netwinder())
202                 return -ENODEV;
203
204         retval = misc_register(&watchdog_miscdev);
205         if (retval < 0)
206                 return retval;
207
208         printk(KERN_INFO
209                 "Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n",
210                                                                 soft_margin);
211
212         if (machine_is_cats())
213                 printk(KERN_WARNING
214                   "Warning: Watchdog reset may not work on this machine.\n");
215         return 0;
216 }
217
218 static void __exit footbridge_watchdog_exit(void)
219 {
220         misc_deregister(&watchdog_miscdev);
221 }
222
223 MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>");
224 MODULE_DESCRIPTION("Footbridge watchdog driver");
225 MODULE_LICENSE("GPL");
226 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
227
228 module_param(soft_margin, int, 0);
229 MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds");
230
231 module_init(footbridge_watchdog_init);
232 module_exit(footbridge_watchdog_exit);