drivers/char/wdt977.c

   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);