drivers/char/watchdog/wdt977.c

   1 /*
   2  *      Wdt977  0.03:   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  *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
  15  *           Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
  16  *      19-Dec-2001 Woody Suwalski: Netwinder fixes, ioctl interface
  17  *      06-Jan-2002 Woody Suwalski: For compatibility, convert all timeouts
  18  *                                  from minutes to seconds.
  19  *      07-Jul-2003 Daniele Bellucci: Audit return code of misc_register in
  20  *                                    nwwatchdog_init.
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/moduleparam.h>
  25 #include <linux/config.h>
  26 #include <linux/types.h>
  27 #include <linux/kernel.h>
  28 #include <linux/fs.h>
  29 #include <linux/miscdevice.h>
  30 #include <linux/init.h>
  31 #include <linux/watchdog.h>
  32 #include <linux/notifier.h>
  33 #include <linux/reboot.h>
  34
  35 #include <asm/io.h>
  36 #include <asm/system.h>
  37 #include <asm/mach-types.h>
  38 #include <asm/uaccess.h>
  39
  40 #define PFX "Wdt977: "
  41 #define WATCHDOG_MINOR  130
  42
  43 #define DEFAULT_TIMEOUT 60                      /* default timeout in seconds */
  44
  45 static  int timeout = DEFAULT_TIMEOUT;
  46 static  int timeoutM;                           /* timeout in minutes */
  47 static  unsigned long timer_alive;
  48 static  int testmode;
  49 static  char expect_close;
  50
  51 module_param(timeout, int, 0);
  52 MODULE_PARM_DESC(timeout,"Watchdog timeout in seconds (60..15300), default=" __MODULE_STRING(DEFAULT_TIMEOUT) ")");
  53 module_param(testmode, int, 0);
  54 MODULE_PARM_DESC(testmode,"Watchdog testmode (1 = no reboot), default=0");
  55
  56 static int nowayout = WATCHDOG_NOWAYOUT;
  57 module_param(nowayout, int, 0);
  58 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
  59
  60 /*
  61  * Start the watchdog
  62  */
  63
  64 static int wdt977_start(void)
  65 {
  66         /* unlock the SuperIO chip */
  67         outb(0x87,0x370);
  68         outb(0x87,0x370);
  69
  70         /* select device Aux2 (device=8) and set watchdog regs F2, F3 and F4
  71          * F2 has the timeout in minutes
  72          * F3 could be set to the POWER LED blink (with GP17 set to PowerLed)
  73          *   at timeout, and to reset timer on kbd/mouse activity (not impl.)
  74          * F4 is used to just clear the TIMEOUT'ed state (bit 0)
  75          */
  76         outb(0x07,0x370);
  77         outb(0x08,0x371);
  78         outb(0xF2,0x370);
  79         outb(timeoutM,0x371);
  80         outb(0xF3,0x370);
  81         outb(0x00,0x371);       /* another setting is 0E for kbd/mouse/LED */
  82         outb(0xF4,0x370);
  83         outb(0x00,0x371);
  84
  85         /* at last select device Aux1 (dev=7) and set GP16 as a watchdog output */
  86         /* in test mode watch the bit 1 on F4 to indicate "triggered" */
  87         if (!testmode)
  88         {
  89                 outb(0x07,0x370);
  90                 outb(0x07,0x371);
  91                 outb(0xE6,0x370);
  92                 outb(0x08,0x371);
  93         }
  94
  95         /* lock the SuperIO chip */
  96         outb(0xAA,0x370);
  97
  98         printk(KERN_INFO PFX "activated.\n");
  99
 100         return 0;
 101 }
 102
 103 /*
 104  * Stop the watchdog
 105  */
 106
 107 static int wdt977_stop(void)
 108 {
 109         /* unlock the SuperIO chip */
 110         outb(0x87,0x370);
 111         outb(0x87,0x370);
 112
 113         /* select device Aux2 (device=8) and set watchdog regs F2,F3 and F4
 114         * F3 is reset to its default state
 115         * F4 can clear the TIMEOUT'ed state (bit 0) - back to default
 116         * We can not use GP17 as a PowerLed, as we use its usage as a RedLed
 117         */
 118         outb(0x07,0x370);
 119         outb(0x08,0x371);
 120         outb(0xF2,0x370);
 121         outb(0xFF,0x371);
 122         outb(0xF3,0x370);
 123         outb(0x00,0x371);
 124         outb(0xF4,0x370);
 125         outb(0x00,0x371);
 126         outb(0xF2,0x370);
 127         outb(0x00,0x371);
 128
 129         /* at last select device Aux1 (dev=7) and set GP16 as a watchdog output */
 130         outb(0x07,0x370);
 131         outb(0x07,0x371);
 132         outb(0xE6,0x370);
 133         outb(0x08,0x371);
 134
 135         /* lock the SuperIO chip */
 136         outb(0xAA,0x370);
 137
 138         printk(KERN_INFO PFX "shutdown.\n");
 139
 140         return 0;
 141 }
 142
 143 /*
 144  * Send a keepalive ping to the watchdog
 145  * This is done by simply re-writing the timeout to reg. 0xF2
 146  */
 147
 148 static int wdt977_keepalive(void)
 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         outb(0x07,0x370);
 157         outb(0x08,0x371);
 158         outb(0xF2,0x370);
 159         outb(timeoutM,0x371);
 160
 161         /* lock the SuperIO chip */
 162         outb(0xAA,0x370);
 163
 164         return 0;
 165 }
 166
 167 /*
 168  * Set the watchdog timeout value
 169  */
 170
 171 static int wdt977_set_timeout(int t)
 172 {
 173         int tmrval;
 174
 175         /* convert seconds to minutes, rounding up */
 176         tmrval = (t + 59) / 60;
 177
 178         if (machine_is_netwinder()) {
 179                 /* we have a hw bug somewhere, so each 977 minute is actually only 30sec
 180                  *  this limits the max timeout to half of device max of 255 minutes...
 181                  */
 182                 tmrval += tmrval;
 183         }
 184
 185         if ((tmrval < 1) || (tmrval > 255))
 186                 return -EINVAL;
 187
 188         /* timeout is the timeout in seconds, timeoutM is the timeout in minutes) */
 189         timeout = t;
 190         timeoutM = tmrval;
 191         return 0;
 192 }
 193
 194 /*
 195  * Get the watchdog status
 196  */
 197
 198 static int wdt977_get_status(int *status)
 199 {
 200         int new_status;
 201
 202         *status=0;
 203
 204         /* unlock the SuperIO chip */
 205         outb(0x87,0x370);
 206         outb(0x87,0x370);
 207
 208         /* select device Aux2 (device=8) and read watchdog reg F4 */
 209         outb(0x07,0x370);
 210         outb(0x08,0x371);
 211         outb(0xF4,0x370);
 212         new_status = inb(0x371);
 213
 214         /* lock the SuperIO chip */
 215         outb(0xAA,0x370);
 216
 217         if (new_status & 1)
 218                 *status |= WDIOF_CARDRESET;
 219
 220         return 0;
 221 }
 222
 223
 224 /*
 225  *      /dev/watchdog handling
 226  */
 227
 228 static int wdt977_open(struct inode *inode, struct file *file)
 229 {
 230         /* If the watchdog is alive we don't need to start it again */
 231         if( test_and_set_bit(0,&timer_alive) )
 232                 return -EBUSY;
 233
 234         if (nowayout)
 235                 __module_get(THIS_MODULE);
 236
 237         wdt977_start();
 238         return nonseekable_open(inode, file);
 239 }
 240
 241 static int wdt977_release(struct inode *inode, struct file *file)
 242 {
 243         /*
 244          *      Shut off the timer.
 245          *      Lock it in if it's a module and we set nowayout
 246          */
 247         if (expect_close == 42)
 248         {
 249                 wdt977_stop();
 250                 clear_bit(0,&timer_alive);
 251         } else {
 252                 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
 253                 wdt977_keepalive();
 254         }
 255         expect_close = 0;
 256         return 0;
 257 }
 258
 259
 260 /*
 261  *      wdt977_write:
 262  *      @file: file handle to the watchdog
 263  *      @buf: buffer to write (unused as data does not matter here
 264  *      @count: count of bytes
 265  *      @ppos: pointer to the position to write. No seeks allowed
 266  *
 267  *      A write to a watchdog device is defined as a keepalive signal. Any
 268  *      write of data will do, as we we don't define content meaning.
 269  */
 270
 271 static ssize_t wdt977_write(struct file *file, const char __user *buf,
 272                             size_t count, loff_t *ppos)
 273 {
 274         if (count) {
 275                 if (!nowayout) {
 276                         size_t i;
 277
 278                         /* In case it was set long ago */
 279                         expect_close = 0;
 280
 281                         for (i = 0; i != count; i++) {
 282                                 char c;
 283                                 if (get_user(c, buf + i))
 284                                         return -EFAULT;
 285                                 if (c == 'V')
 286                                         expect_close = 42;
 287                         }
 288                 }
 289
 290                 wdt977_keepalive();
 291         }
 292         return count;
 293 }
 294
 295 /*
 296  *      wdt977_ioctl:
 297  *      @inode: inode of the device
 298  *      @file: file handle to the device
 299  *      @cmd: watchdog command
 300  *      @arg: argument pointer
 301  *
 302  *      The watchdog API defines a common set of functions for all watchdogs
 303  *      according to their available features.
 304  */
 305
 306 static struct watchdog_info ident = {
 307         .options =              WDIOF_SETTIMEOUT |
 308                                 WDIOF_MAGICCLOSE |
 309                                 WDIOF_KEEPALIVEPING,
 310         .firmware_version =     1,
 311         .identity =             "Winbond 83977",
 312 };
 313
 314 static int wdt977_ioctl(struct inode *inode, struct file *file,
 315         unsigned int cmd, unsigned long arg)
 316 {
 317         int status;
 318         int new_options, retval = -EINVAL;
 319         int new_timeout;
 320         union {
 321                 struct watchdog_info __user *ident;
 322                 int __user *i;
 323         } uarg;
 324
 325         uarg.i = (int __user *)arg;
 326
 327         switch(cmd)
 328         {
 329         default:
 330                 return -ENOIOCTLCMD;
 331
 332         case WDIOC_GETSUPPORT:
 333                 return copy_to_user(uarg.ident, &ident,
 334                         sizeof(ident)) ? -EFAULT : 0;
 335
 336         case WDIOC_GETSTATUS:
 337                 wdt977_get_status(&status);
 338                 return put_user(status, uarg.i);
 339
 340         case WDIOC_GETBOOTSTATUS:
 341                 return put_user(0, uarg.i);
 342
 343         case WDIOC_KEEPALIVE:
 344                 wdt977_keepalive();
 345                 return 0;
 346
 347         case WDIOC_SETOPTIONS:
 348                 if (get_user (new_options, uarg.i))
 349                         return -EFAULT;
 350
 351                 if (new_options & WDIOS_DISABLECARD) {
 352                         wdt977_stop();
 353                         retval = 0;
 354                 }
 355
 356                 if (new_options & WDIOS_ENABLECARD) {
 357                         wdt977_start();
 358                         retval = 0;
 359                 }
 360
 361                 return retval;
 362
 363         case WDIOC_SETTIMEOUT:
 364                 if (get_user(new_timeout, uarg.i))
 365                         return -EFAULT;
 366
 367                 if (wdt977_set_timeout(new_timeout))
 368                     return -EINVAL;
 369
 370                 wdt977_keepalive();
 371                 /* Fall */
 372
 373         case WDIOC_GETTIMEOUT:
 374                 return put_user(timeout, uarg.i);
 375
 376         }
 377 }
 378
 379 static int wdt977_notify_sys(struct notifier_block *this, unsigned long code,
 380         void *unused)
 381 {
 382         if(code==SYS_DOWN || code==SYS_HALT)
 383                 wdt977_stop();
 384         return NOTIFY_DONE;
 385 }
 386
 387 static struct file_operations wdt977_fops=
 388 {
 389         .owner          = THIS_MODULE,
 390         .llseek         = no_llseek,
 391         .write          = wdt977_write,
 392         .ioctl          = wdt977_ioctl,
 393         .open           = wdt977_open,
 394         .release        = wdt977_release,
 395 };
 396
 397 static struct miscdevice wdt977_miscdev=
 398 {
 399         .minor          = WATCHDOG_MINOR,
 400         .name           = "watchdog",
 401         .fops           = &wdt977_fops,
 402 };
 403
 404 static struct notifier_block wdt977_notifier = {
 405         .notifier_call = wdt977_notify_sys,
 406 };
 407
 408 static int __init nwwatchdog_init(void)
 409 {
 410         int retval;
 411         if (!machine_is_netwinder())
 412                 return -ENODEV;
 413
 414         /* Check that the timeout value is within it's range ; if not reset to the default */
 415         if (wdt977_set_timeout(timeout)) {
 416                 wdt977_set_timeout(DEFAULT_TIMEOUT);
 417                 printk(KERN_INFO PFX "timeout value must be 60<timeout<15300, using %d\n",
 418                         DEFAULT_TIMEOUT);
 419         }
 420
 421         retval = register_reboot_notifier(&wdt977_notifier);
 422         if (retval) {
 423                 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 424                         retval);
 425                 return retval;
 426         }
 427
 428         retval = misc_register(&wdt977_miscdev);
 429         if (retval) {
 430                 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 431                         WATCHDOG_MINOR, retval);
 432                 unregister_reboot_notifier(&wdt977_notifier);
 433                 return retval;
 434         }
 435
 436         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d, testmode = %i)\n",
 437                 timeout, nowayout, testmode);
 438
 439         return 0;
 440 }
 441
 442 static void __exit nwwatchdog_exit(void)
 443 {
 444         misc_deregister(&wdt977_miscdev);
 445         unregister_reboot_notifier(&wdt977_notifier);
 446 }
 447
 448 module_init(nwwatchdog_init);
 449 module_exit(nwwatchdog_exit);
 450
 451 MODULE_AUTHOR("Woody Suwalski <woody@netwinder.org>");
 452 MODULE_DESCRIPTION("W83977AF Watchdog driver");
 453 MODULE_LICENSE("GPL");
 454 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);