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