1 /*
2 * Wdt977 0.01: A Watchdog Device for Netwinder W83977AF chip
3 *
4 * (c) Copyright 1998 Rebel.com (Woody Suwalski <woody@netwinder.org>)
5 *
6 * -----------------------
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 * -----------------------
14 */
15
16 #include <linux/module.h>
17 #include <linux/config.h>
18 #include <linux/types.h>
19 #include <linux/kernel.h>
20 #include <linux/fs.h>
21 #include <linux/miscdevice.h>
22 #include <linux/init.h>
23 #include <linux/smp_lock.h>
24
25 #include <asm/io.h>
26 #include <asm/system.h>
27 #include <asm/mach-types.h>
28
29 #define WATCHDOG_MINOR 130
30
31 static int timeout = 3;
32 static int timer_alive;
33 static int testmode;
34
35 /*
36 * Allow only one person to hold it open
37 */
38
39 static int wdt977_open(struct inode *inode, struct file *file)
40 {
41 if(timer_alive)
42 return -EBUSY;
43 #ifdef CONFIG_WATCHDOG_NOWAYOUT
44 MOD_INC_USE_COUNT;
45 #endif
46 timer_alive++;
47
48 //max timeout value = 255 minutes (0xFF). Write 0 to disable WatchDog.
49 if (timeout>255)
50 timeout = 255;
51
52 printk(KERN_INFO "Watchdog: active, current timeout %d min.\n",timeout);
53
54 // unlock the SuperIO chip
55 outb(0x87,0x370);
56 outb(0x87,0x370);
57
58 //select device Aux2 (device=8) and set watchdog regs F2, F3 and F4
59 //F2 has the timeout in minutes
60 //F3 could be set to the POWER LED blink (with GP17 set to PowerLed)
61 // at timeout, and to reset timer on kbd/mouse activity (not now)
62 //F4 is used to just clear the TIMEOUT'ed state (bit 0)
63
64 outb(0x07,0x370);
65 outb(0x08,0x371);
66 outb(0xF2,0x370);
67 outb(timeout,0x371);
68 outb(0xF3,0x370);
69 outb(0x00,0x371); //another setting is 0E for kbd/mouse/LED
70 outb(0xF4,0x370);
71 outb(0x00,0x371);
72
73 //at last select device Aux1 (dev=7) and set GP16 as a watchdog output
74 if (!testmode)
75 {
76 outb(0x07,0x370);
77 outb(0x07,0x371);
78 outb(0xE6,0x370);
79 outb(0x08,0x371);
80 }
81
82 // lock the SuperIO chip
83 outb(0xAA,0x370);
84
85 return 0;
86 }
87
88 static int wdt977_release(struct inode *inode, struct file *file)
89 {
90 /*
91 * Shut off the timer.
92 * Lock it in if it's a module and we defined ...NOWAYOUT
93 */
94 #ifndef CONFIG_WATCHDOG_NOWAYOUT
95 lock_kernel();
96
97 // unlock the SuperIO chip
98 outb(0x87,0x370);
99 outb(0x87,0x370);
100
101 //select device Aux2 (device=8) and set watchdog regs F2,F3 and F4
102 //F3 is reset to its default state
103 //F4 can clear the TIMEOUT'ed state (bit 0) - back to default
104 //We can not use GP17 as a PowerLed, as we use its usage as a RedLed
105
106 outb(0x07,0x370);
107 outb(0x08,0x371);
108 outb(0xF2,0x370);
109 outb(0xFF,0x371);
110 outb(0xF3,0x370);
111 outb(0x00,0x371);
112 outb(0xF4,0x370);
113 outb(0x00,0x371);
114 outb(0xF2,0x370);
115 outb(0x00,0x371);
116
117 //at last select device Aux1 (dev=7) and set GP16 as a watchdog output
118 outb(0x07,0x370);
119 outb(0x07,0x371);
120 outb(0xE6,0x370);
121 outb(0x08,0x371);
122
123 // lock the SuperIO chip
124 outb(0xAA,0x370);
125
126 timer_alive=0;
127 unlock_kernel();
128
129 printk(KERN_INFO "Watchdog: shutdown.\n");
130 #endif
131 return 0;
132 }
133
134 static ssize_t wdt977_write(struct file *file, const char *data, size_t len, loff_t *ppos)
135 {
136
137 //max timeout value = 255 minutes (0xFF). Write 0 to disable WatchDog.
138 if (timeout>255)
139 timeout = 255;
140
141 /*
142 * Refresh the timer.
143 */
144
145 //we have a hw bug somewhere, so each 977 minute is actually only 30sec
146 //as such limit the max timeout to half of max of 255 minutes...
147 // if (timeout>126)
148 // timeout = 126;
149
150 // unlock the SuperIO chip
151 outb(0x87,0x370);
152 outb(0x87,0x370);
153
154 //select device Aux2 (device=8) and kicks watchdog reg F2
155 //F2 has the timeout in minutes
156
157 outb(0x07,0x370);
158 outb(0x08,0x371);
159 outb(0xF2,0x370);
160 outb(timeout,0x371);
161
162 // lock the SuperIO chip
163 outb(0xAA,0x370);
164
165 return 1;
166 }
167
168 static struct file_operations wdt977_fops=
169 {
170 owner: THIS_MODULE,
171 write: wdt977_write,
172 open: wdt977_open,
173 release: wdt977_release,
174 };
175
176 static struct miscdevice wdt977_miscdev=
177 {
178 WATCHDOG_MINOR,
179 "watchdog",
180 &wdt977_fops
181 };
182
183 static int __init nwwatchdog_init(void)
184 {
185 if (!machine_is_netwinder())
186 return -ENODEV;
187
188 misc_register(&wdt977_miscdev);
189 printk(KERN_INFO "NetWinder Watchdog sleeping.\n");
190 return 0;
191 }
192
193 static void __exit nwwatchdog_exit(void)
194 {
195 misc_deregister(&wdt977_miscdev);
196 }
197
198 EXPORT_NO_SYMBOLS;
199
200 module_init(nwwatchdog_init);
201 module_exit(nwwatchdog_exit);
202
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