drivers/char/watchdog/indydog.c

   1 /*
   2  *      IndyDog 0.3     A Hardware Watchdog Device for SGI IP22
   3  *
   4  *      (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>, All Rights Reserved.
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  *
  11  *      based on softdog.c by Alan Cox <alan@redhat.com>
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/moduleparam.h>
  16 #include <linux/config.h>
  17 #include <linux/types.h>
  18 #include <linux/kernel.h>
  19 #include <linux/fs.h>
  20 #include <linux/mm.h>
  21 #include <linux/miscdevice.h>
  22 #include <linux/watchdog.h>
  23 #include <linux/notifier.h>
  24 #include <linux/reboot.h>
  25 #include <linux/init.h>
  26 #include <asm/uaccess.h>
  27 #include <asm/sgi/mc.h>
  28
  29 #define PFX "indydog: "
  30 static int indydog_alive;
  31
  32 #define WATCHDOG_TIMEOUT 30             /* 30 sec default timeout */
  33
  34 static int nowayout = WATCHDOG_NOWAYOUT;
  35 module_param(nowayout, int, 0);
  36 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
  37
  38 static void indydog_start(void)
  39 {
  40         u32 mc_ctrl0 = sgimc->cpuctrl0;
  41
  42         mc_ctrl0 = sgimc->cpuctrl0 | SGIMC_CCTRL0_WDOG;
  43         sgimc->cpuctrl0 = mc_ctrl0;
  44 }
  45
  46 static void indydog_stop(void)
  47 {
  48         u32 mc_ctrl0 = sgimc->cpuctrl0;
  49
  50         mc_ctrl0 &= ~SGIMC_CCTRL0_WDOG;
  51         sgimc->cpuctrl0 = mc_ctrl0;
  52
  53         printk(KERN_INFO PFX "Stopped watchdog timer.\n");
  54 }
  55
  56 static void indydog_ping(void)
  57 {
  58         sgimc->watchdogt = 0;
  59 }
  60
  61 /*
  62  *      Allow only one person to hold it open
  63  */
  64 static int indydog_open(struct inode *inode, struct file *file)
  65 {
  66         if (indydog_alive)
  67                 return -EBUSY;
  68
  69         if (nowayout)
  70                 __module_get(THIS_MODULE);
  71
  72         /* Activate timer */
  73         indydog_start();
  74         indydog_ping();
  75
  76         indydog_alive = 1;
  77         printk(KERN_INFO "Started watchdog timer.\n");
  78
  79         return nonseekable_open(inode, file);
  80 }
  81
  82 static int indydog_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                 indydog_stop();         /* Turn the WDT off */
  88
  89         indydog_alive = 0;
  90
  91         return 0;
  92 }
  93
  94 static ssize_t indydog_write(struct file *file, const char *data, size_t len, loff_t *ppos)
  95 {
  96         /* Refresh the timer. */
  97         if (len) {
  98                 indydog_ping();
  99         }
 100         return len;
 101 }
 102
 103 static int indydog_ioctl(struct inode *inode, struct file *file,
 104         unsigned int cmd, unsigned long arg)
 105 {
 106         int options, retval = -EINVAL;
 107         static struct watchdog_info ident = {
 108                 .options                = WDIOF_KEEPALIVEPING |
 109                                           WDIOF_MAGICCLOSE,
 110                 .firmware_version       = 0,
 111                 .identity               = "Hardware Watchdog for SGI IP22",
 112         };
 113
 114         switch (cmd) {
 115                 default:
 116                         return -ENOIOCTLCMD;
 117                 case WDIOC_GETSUPPORT:
 118                         if (copy_to_user((struct watchdog_info *)arg,
 119                                          &ident, sizeof(ident)))
 120                                 return -EFAULT;
 121                         return 0;
 122                 case WDIOC_GETSTATUS:
 123                 case WDIOC_GETBOOTSTATUS:
 124                         return put_user(0,(int *)arg);
 125                 case WDIOC_KEEPALIVE:
 126                         indydog_ping();
 127                         return 0;
 128                 case WDIOC_GETTIMEOUT:
 129                         return put_user(WATCHDOG_TIMEOUT,(int *)arg);
 130                 case WDIOC_SETOPTIONS:
 131                 {
 132                         if (get_user(options, (int *)arg))
 133                                 return -EFAULT;
 134
 135                         if (options & WDIOS_DISABLECARD) {
 136                                 indydog_stop();
 137                                 retval = 0;
 138                         }
 139
 140                         if (options & WDIOS_ENABLECARD) {
 141                                 indydog_start();
 142                                 retval = 0;
 143                         }
 144
 145                         return retval;
 146                 }
 147         }
 148 }
 149
 150 static int indydog_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
 151 {
 152         if (code == SYS_DOWN || code == SYS_HALT)
 153                 indydog_stop();         /* Turn the WDT off */
 154
 155         return NOTIFY_DONE;
 156 }
 157
 158 static struct file_operations indydog_fops = {
 159         .owner          = THIS_MODULE,
 160         .llseek         = no_llseek,
 161         .write          = indydog_write,
 162         .ioctl          = indydog_ioctl,
 163         .open           = indydog_open,
 164         .release        = indydog_release,
 165 };
 166
 167 static struct miscdevice indydog_miscdev = {
 168         .minor          = WATCHDOG_MINOR,
 169         .name           = "watchdog",
 170         .fops           = &indydog_fops,
 171 };
 172
 173 static struct notifier_block indydog_notifier = {
 174         .notifier_call = indydog_notify_sys,
 175 };
 176
 177 static char banner[] __initdata =
 178         KERN_INFO PFX "Hardware Watchdog Timer for SGI IP22: 0.3\n";
 179
 180 static int __init watchdog_init(void)
 181 {
 182         int ret;
 183
 184         ret = register_reboot_notifier(&indydog_notifier);
 185         if (ret) {
 186                 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 187                         ret);
 188                 return ret;
 189         }
 190
 191         ret = misc_register(&indydog_miscdev);
 192         if (ret) {
 193                 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 194                         WATCHDOG_MINOR, ret);
 195                 unregister_reboot_notifier(&indydog_notifier);
 196                 return ret;
 197         }
 198
 199         printk(banner);
 200
 201         return 0;
 202 }
 203
 204 static void __exit watchdog_exit(void)
 205 {
 206         misc_deregister(&indydog_miscdev);
 207         unregister_reboot_notifier(&indydog_notifier);
 208 }
 209
 210 module_init(watchdog_init);
 211 module_exit(watchdog_exit);
 212
 213 MODULE_AUTHOR("Guido Guenther <agx@sigxcpu.org>");
 214 MODULE_DESCRIPTION("Hardware Watchdog Device for SGI IP22");
 215 MODULE_LICENSE("GPL");
 216 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);