SAFE public projects git trees. - safe/jmp/linux-2.6/blob - drivers/watchdog/wafer5823wdt.c

   1 /*
   2  *      ICP Wafer 5823 Single Board Computer WDT driver
   3  *      http://www.icpamerica.com/wafer_5823.php
   4  *      May also work on other similar models
   5  *
   6  *      (c) Copyright 2002 Justin Cormack <justin@street-vision.com>
   7  *
   8  *      Release 0.02
   9  *
  10  *      Based on advantechwdt.c which is based on wdt.c.
  11  *      Original copyright messages:
  12  *
  13  *      (c) Copyright 1996-1997 Alan Cox <alan@redhat.com>, All Rights Reserved.
  14  *                              http://www.redhat.com
  15  *
  16  *      This program is free software; you can redistribute it and/or
  17  *      modify it under the terms of the GNU General Public License
  18  *      as published by the Free Software Foundation; either version
  19  *      2 of the License, or (at your option) any later version.
  20  *
  21  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  22  *      warranty for any of this software. This material is provided
  23  *      "AS-IS" and at no charge.
  24  *
  25  *      (c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
  26  *
  27  */
  28
  29 #include <linux/module.h>
  30 #include <linux/moduleparam.h>
  31 #include <linux/miscdevice.h>
  32 #include <linux/watchdog.h>
  33 #include <linux/fs.h>
  34 #include <linux/ioport.h>
  35 #include <linux/notifier.h>
  36 #include <linux/reboot.h>
  37 #include <linux/init.h>
  38 #include <linux/spinlock.h>
  39 #include <linux/io.h>
  40 #include <linux/uaccess.h>
  41
  42 #define WATCHDOG_NAME "Wafer 5823 WDT"
  43 #define PFX WATCHDOG_NAME ": "
  44 #define WD_TIMO 60                      /* 60 sec default timeout */
  45
  46 static unsigned long wafwdt_is_open;
  47 static char expect_close;
  48 static DEFINE_SPINLOCK(wafwdt_lock);
  49
  50 /*
  51  *      You must set these - there is no sane way to probe for this board.
  52  *
  53  *      To enable, write the timeout value in seconds (1 to 255) to I/O
  54  *      port WDT_START, then read the port to start the watchdog. To pat
  55  *      the dog, read port WDT_STOP to stop the timer, then read WDT_START
  56  *      to restart it again.
  57  */
  58
  59 static int wdt_stop = 0x843;
  60 static int wdt_start = 0x443;
  61
  62 static int timeout = WD_TIMO;  /* in seconds */
  63 module_param(timeout, int, 0);
  64 MODULE_PARM_DESC(timeout,
  65                 "Watchdog timeout in seconds. 1 <= timeout <= 255, default="
  66                                 __MODULE_STRING(WD_TIMO) ".");
  67
  68 static int nowayout = WATCHDOG_NOWAYOUT;
  69 module_param(nowayout, int, 0);
  70 MODULE_PARM_DESC(nowayout,
  71                 "Watchdog cannot be stopped once started (default="
  72                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  73
  74 static void wafwdt_ping(void)
  75 {
  76         /* pat watchdog */
  77         spin_lock(&wafwdt_lock);
  78         inb_p(wdt_stop);
  79         inb_p(wdt_start);
  80         spin_unlock(&wafwdt_lock);
  81 }
  82
  83 static void wafwdt_start(void)
  84 {
  85         /* start up watchdog */
  86         outb_p(timeout, wdt_start);
  87         inb_p(wdt_start);
  88 }
  89
  90 static void
  91 wafwdt_stop(void)
  92 {
  93         /* stop watchdog */
  94         inb_p(wdt_stop);
  95 }
  96
  97 static ssize_t wafwdt_write(struct file *file, const char __user *buf,
  98                                                 size_t count, loff_t *ppos)
  99 {
 100         /* See if we got the magic character 'V' and reload the timer */
 101         if (count) {
 102                 if (!nowayout) {
 103                         size_t i;
 104
 105                         /* In case it was set long ago */
 106                         expect_close = 0;
 107
 108                         /* scan to see whether or not we got the magic
 109                            character */
 110                         for (i = 0; i != count; i++) {
 111                                 char c;
 112                                 if (get_user(c, buf + i))
 113                                         return -EFAULT;
 114                                 if (c == 'V')
 115                                         expect_close = 42;
 116                         }
 117                 }
 118                 /* Well, anyhow someone wrote to us, we should
 119                    return that favour */
 120                 wafwdt_ping();
 121         }
 122         return count;
 123 }
 124
 125 static long wafwdt_ioctl(struct file *file, unsigned int cmd,
 126                                                         unsigned long arg)
 127 {
 128         int new_timeout;
 129         void __user *argp = (void __user *)arg;
 130         int __user *p = argp;
 131         static const struct watchdog_info ident = {
 132                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
 133                                                         WDIOF_MAGICCLOSE,
 134                 .firmware_version = 1,
 135                 .identity = "Wafer 5823 WDT",
 136         };
 137
 138         switch (cmd) {
 139         case WDIOC_GETSUPPORT:
 140                 if (copy_to_user(argp, &ident, sizeof(ident)))
 141                         return -EFAULT;
 142                 break;
 143
 144         case WDIOC_GETSTATUS:
 145         case WDIOC_GETBOOTSTATUS:
 146                 return put_user(0, p);
 147
 148         case WDIOC_SETOPTIONS:
 149         {
 150                 int options, retval = -EINVAL;
 151
 152                 if (get_user(options, p))
 153                         return -EFAULT;
 154
 155                 if (options & WDIOS_DISABLECARD) {
 156                         wafwdt_start();
 157                         retval = 0;
 158                 }
 159
 160                 if (options & WDIOS_ENABLECARD) {
 161                         wafwdt_stop();
 162                         retval = 0;
 163                 }
 164
 165                 return retval;
 166         }
 167
 168         case WDIOC_KEEPALIVE:
 169                 wafwdt_ping();
 170                 break;
 171
 172         case WDIOC_SETTIMEOUT:
 173                 if (get_user(new_timeout, p))
 174                         return -EFAULT;
 175                 if ((new_timeout < 1) || (new_timeout > 255))
 176                         return -EINVAL;
 177                 timeout = new_timeout;
 178                 wafwdt_stop();
 179                 wafwdt_start();
 180                 /* Fall */
 181         case WDIOC_GETTIMEOUT:
 182                 return put_user(timeout, p);
 183
 184         default:
 185                 return -ENOTTY;
 186         }
 187         return 0;
 188 }
 189
 190 static int wafwdt_open(struct inode *inode, struct file *file)
 191 {
 192         if (test_and_set_bit(0, &wafwdt_is_open))
 193                 return -EBUSY;
 194
 195         /*
 196          *      Activate
 197          */
 198         wafwdt_start();
 199         return nonseekable_open(inode, file);
 200 }
 201
 202 static int
 203 wafwdt_close(struct inode *inode, struct file *file)
 204 {
 205         if (expect_close == 42)
 206                 wafwdt_stop();
 207         else {
 208                 printk(KERN_CRIT PFX
 209                     "WDT device closed unexpectedly.  WDT will not stop!\n");
 210                 wafwdt_ping();
 211         }
 212         clear_bit(0, &wafwdt_is_open);
 213         expect_close = 0;
 214         return 0;
 215 }
 216
 217 /*
 218  *      Notifier for system down
 219  */
 220
 221 static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code,
 222                                                                 void *unused)
 223 {
 224         if (code == SYS_DOWN || code == SYS_HALT)
 225                 wafwdt_stop();
 226         return NOTIFY_DONE;
 227 }
 228
 229 /*
 230  *      Kernel Interfaces
 231  */
 232
 233 static const struct file_operations wafwdt_fops = {
 234         .owner          = THIS_MODULE,
 235         .llseek         = no_llseek,
 236         .write          = wafwdt_write,
 237         .unlocked_ioctl = wafwdt_ioctl,
 238         .open           = wafwdt_open,
 239         .release        = wafwdt_close,
 240 };
 241
 242 static struct miscdevice wafwdt_miscdev = {
 243         .minor  = WATCHDOG_MINOR,
 244         .name   = "watchdog",
 245         .fops   = &wafwdt_fops,
 246 };
 247
 248 /*
 249  *      The WDT needs to learn about soft shutdowns in order to
 250  *      turn the timebomb registers off.
 251  */
 252
 253 static struct notifier_block wafwdt_notifier = {
 254         .notifier_call = wafwdt_notify_sys,
 255 };
 256
 257 static int __init wafwdt_init(void)
 258 {
 259         int ret;
 260
 261         printk(KERN_INFO
 262           "WDT driver for Wafer 5823 single board computer initialising.\n");
 263
 264         if (timeout < 1 || timeout > 255) {
 265                 timeout = WD_TIMO;
 266                 printk(KERN_INFO PFX
 267                         "timeout value must be 1 <= x <= 255, using %d\n",
 268                                                                 timeout);
 269         }
 270
 271         if (wdt_stop != wdt_start) {
 272                 if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
 273                         printk(KERN_ERR PFX
 274                                 "I/O address 0x%04x already in use\n",
 275                                                                 wdt_stop);
 276                         ret = -EIO;
 277                         goto error;
 278                 }
 279         }
 280
 281         if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
 282                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
 283                         wdt_start);
 284                 ret = -EIO;
 285                 goto error2;
 286         }
 287
 288         ret = register_reboot_notifier(&wafwdt_notifier);
 289         if (ret != 0) {
 290                 printk(KERN_ERR PFX
 291                         "cannot register reboot notifier (err=%d)\n", ret);
 292                 goto error3;
 293         }
 294
 295         ret = misc_register(&wafwdt_miscdev);
 296         if (ret != 0) {
 297                 printk(KERN_ERR PFX
 298                         "cannot register miscdev on minor=%d (err=%d)\n",
 299                                                 WATCHDOG_MINOR, ret);
 300                 goto error4;
 301         }
 302
 303         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 304                 timeout, nowayout);
 305
 306         return ret;
 307 error4:
 308         unregister_reboot_notifier(&wafwdt_notifier);
 309 error3:
 310         release_region(wdt_start, 1);
 311 error2:
 312         if (wdt_stop != wdt_start)
 313                 release_region(wdt_stop, 1);
 314 error:
 315         return ret;
 316 }
 317
 318 static void __exit wafwdt_exit(void)
 319 {
 320         misc_deregister(&wafwdt_miscdev);
 321         unregister_reboot_notifier(&wafwdt_notifier);
 322         if (wdt_stop != wdt_start)
 323                 release_region(wdt_stop, 1);
 324         release_region(wdt_start, 1);
 325 }
 326
 327 module_init(wafwdt_init);
 328 module_exit(wafwdt_exit);
 329
 330 MODULE_AUTHOR("Justin Cormack");
 331 MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
 332 MODULE_LICENSE("GPL");
 333 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 334
 335 /* end of wafer5823wdt.c */