1 /*
2 * SBC EPX C3 0.1 A Hardware Watchdog Device for the Winsystems EPX-C3
3 * single board computer
4 *
5 * (c) Copyright 2006 Calin A. Culianu <calin@ajvar.org>, All Rights
6 * Reserved.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 *
13 * based on softdog.c by Alan Cox <alan@redhat.com>
14 */
15
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/types.h>
19 #include <linux/kernel.h>
20 #include <linux/fs.h>
21 #include <linux/mm.h>
22 #include <linux/miscdevice.h>
23 #include <linux/watchdog.h>
24 #include <linux/notifier.h>
25 #include <linux/reboot.h>
26 #include <linux/init.h>
27 #include <linux/ioport.h>
28 #include <asm/uaccess.h>
29 #include <asm/io.h>
30
31 #define PFX "epx_c3: "
32 static int epx_c3_alive;
33
34 #define WATCHDOG_TIMEOUT 1 /* 1 sec default timeout */
35
36 static int nowayout = WATCHDOG_NOWAYOUT;
37 module_param(nowayout, int, 0);
38 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
39
40 #define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */
41 #define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */
42
43 static void epx_c3_start(void)
44 {
45 outb(1, EPXC3_WATCHDOG_CTL_REG);
46 }
47
48 static void epx_c3_stop(void)
49 {
50
51 outb(0, EPXC3_WATCHDOG_CTL_REG);
52
53 printk(KERN_INFO PFX "Stopped watchdog timer.\n");
54 }
55
56 static void epx_c3_pet(void)
57 {
58 outb(1, EPXC3_WATCHDOG_PET_REG);
59 }
60
61 /*
62 * Allow only one person to hold it open
63 */
64 static int epx_c3_open(struct inode *inode, struct file *file)
65 {
66 if (epx_c3_alive)
67 return -EBUSY;
68
69 if (nowayout)
70 __module_get(THIS_MODULE);
71
72 /* Activate timer */
73 epx_c3_start();
74 epx_c3_pet();
75
76 epx_c3_alive = 1;
77 printk(KERN_INFO "Started watchdog timer.\n");
78
79 return nonseekable_open(inode, file);
80 }
81
82 static int epx_c3_release(struct inode *inode, struct file *file)
83 {
84 /* Shut off the timer.
85 * Lock it in if it's a module and we defined ...NOWAYOUT */
86 if (!nowayout)
87 epx_c3_stop(); /* Turn the WDT off */
88
89 epx_c3_alive = 0;
90
91 return 0;
92 }
93
94 static ssize_t epx_c3_write(struct file *file, const char __user *data,
95 size_t len, loff_t *ppos)
96 {
97 /* Refresh the timer. */
98 if (len)
99 epx_c3_pet();
100 return len;
101 }
102
103 static int epx_c3_ioctl(struct inode *inode, struct file *file,
104 unsigned int cmd, unsigned long arg)
105 {
106 int options, retval = -EINVAL;
107 int __user *argp = (void __user *)arg;
108 static struct watchdog_info ident = {
109 .options = WDIOF_KEEPALIVEPING |
110 WDIOF_MAGICCLOSE,
111 .firmware_version = 0,
112 .identity = "Winsystems EPX-C3 H/W Watchdog",
113 };
114
115 switch (cmd) {
116 case WDIOC_GETSUPPORT:
117 if (copy_to_user(argp, &ident, sizeof(ident)))
118 return -EFAULT;
119 return 0;
120 case WDIOC_GETSTATUS:
121 case WDIOC_GETBOOTSTATUS:
122 return put_user(0, argp);
123 case WDIOC_KEEPALIVE:
124 epx_c3_pet();
125 return 0;
126 case WDIOC_GETTIMEOUT:
127 return put_user(WATCHDOG_TIMEOUT, argp);
128 case WDIOC_SETOPTIONS:
129 if (get_user(options, argp))
130 return -EFAULT;
131
132 if (options & WDIOS_DISABLECARD) {
133 epx_c3_stop();
134 retval = 0;
135 }
136
137 if (options & WDIOS_ENABLECARD) {
138 epx_c3_start();
139 retval = 0;
140 }
141
142 return retval;
143 default:
144 return -ENOTTY;
145 }
146 }
147
148 static int epx_c3_notify_sys(struct notifier_block *this, unsigned long code,
149 void *unused)
150 {
151 if (code == SYS_DOWN || code == SYS_HALT)
152 epx_c3_stop(); /* Turn the WDT off */
153
154 return NOTIFY_DONE;
155 }
156
157 static const struct file_operations epx_c3_fops = {
158 .owner = THIS_MODULE,
159 .llseek = no_llseek,
160 .write = epx_c3_write,
161 .ioctl = epx_c3_ioctl,
162 .open = epx_c3_open,
163 .release = epx_c3_release,
164 };
165
166 static struct miscdevice epx_c3_miscdev = {
167 .minor = WATCHDOG_MINOR,
168 .name = "watchdog",
169 .fops = &epx_c3_fops,
170 };
171
172 static struct notifier_block epx_c3_notifier = {
173 .notifier_call = epx_c3_notify_sys,
174 };
175
176 static const char banner[] __initdata =
177 KERN_INFO PFX "Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n";
178
179 static int __init watchdog_init(void)
180 {
181 int ret;
182
183 if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog"))
184 return -EBUSY;
185
186 ret = register_reboot_notifier(&epx_c3_notifier);
187 if (ret) {
188 printk(KERN_ERR PFX "cannot register reboot notifier "
189 "(err=%d)\n", ret);
190 goto out;
191 }
192
193 ret = misc_register(&epx_c3_miscdev);
194 if (ret) {
195 printk(KERN_ERR PFX "cannot register miscdev on minor=%d "
196 "(err=%d)\n", WATCHDOG_MINOR, ret);
197 unregister_reboot_notifier(&epx_c3_notifier);
198 goto out;
199 }
200
201 printk(banner);
202
203 return 0;
204
205 out:
206 release_region(EPXC3_WATCHDOG_CTL_REG, 2);
207 return ret;
208 }
209
210 static void __exit watchdog_exit(void)
211 {
212 misc_deregister(&epx_c3_miscdev);
213 unregister_reboot_notifier(&epx_c3_notifier);
214 release_region(EPXC3_WATCHDOG_CTL_REG, 2);
215 }
216
217 module_init(watchdog_init);
218 module_exit(watchdog_exit);
219
220 MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>");
221 MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC. Note that there is no way to probe for this device -- so only use it if you are *sure* you are runnning on this specific SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!");
222 MODULE_LICENSE("GPL");
223 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
224
|
This page was automatically generated by the
LXR engine.
|