drivers/watchdog/wdt977.c

   1 /*
   2  *      Wdt977  0.04:   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  *      25-Oct-2005 Woody Suwalski: Convert addresses to #defs, add spinlocks
  22  *                                  remove limitiation to be used on
  23  *                                  Netwinders only
  24  */
  25
  26 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  27
  28 #include <linux/module.h>
  29 #include <linux/moduleparam.h>
  30 #include <linux/types.h>
  31 #include <linux/kernel.h>
  32 #include <linux/fs.h>
  33 #include <linux/miscdevice.h>
  34 #include <linux/init.h>
  35 #include <linux/ioport.h>
  36 #include <linux/watchdog.h>
  37 #include <linux/notifier.h>
  38 #include <linux/reboot.h>
  39 #include <linux/io.h>
  40 #include <linux/uaccess.h>
  41
  42 #include <asm/system.h>
  43 #include <asm/mach-types.h>
  44
  45 #define WATCHDOG_VERSION  "0.04"
  46 #define WATCHDOG_NAME     "Wdt977"
  47
  48 #define IO_INDEX_PORT   0x370           /* on some systems it can be 0x3F0 */
  49 #define IO_DATA_PORT    (IO_INDEX_PORT + 1)
  50
  51 #define UNLOCK_DATA     0x87
  52 #define LOCK_DATA       0xAA
  53 #define DEVICE_REGISTER 0x07
  54
  55
  56 #define DEFAULT_TIMEOUT 60                      /* default timeout in seconds */
  57
  58 static  int timeout = DEFAULT_TIMEOUT;
  59 static  int timeoutM;                           /* timeout in minutes */
  60 static  unsigned long timer_alive;
  61 static  int testmode;
  62 static  char expect_close;
  63 static  DEFINE_SPINLOCK(spinlock);
  64
  65 module_param(timeout, int, 0);
  66 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (60..15300, default="
  67                                 __MODULE_STRING(DEFAULT_TIMEOUT) ")");
  68 module_param(testmode, int, 0);
  69 MODULE_PARM_DESC(testmode, "Watchdog testmode (1 = no reboot), default=0");
  70
  71 static bool nowayout = WATCHDOG_NOWAYOUT;
  72 module_param(nowayout, bool, 0);
  73 MODULE_PARM_DESC(nowayout,
  74                 "Watchdog cannot be stopped once started (default="
  75                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  76
  77 /*
  78  * Start the watchdog
  79  */
  80
  81 static int wdt977_start(void)
  82 {
  83         unsigned long flags;
  84
  85         spin_lock_irqsave(&spinlock, flags);
  86
  87         /* unlock the SuperIO chip */
  88         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
  89         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
  90
  91         /* select device Aux2 (device=8) and set watchdog regs F2, F3 and F4
  92          * F2 has the timeout in minutes
  93          * F3 could be set to the POWER LED blink (with GP17 set to PowerLed)
  94          *   at timeout, and to reset timer on kbd/mouse activity (not impl.)
  95          * F4 is used to just clear the TIMEOUT'ed state (bit 0)
  96          */
  97         outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
  98         outb_p(0x08, IO_DATA_PORT);
  99         outb_p(0xF2, IO_INDEX_PORT);
 100         outb_p(timeoutM, IO_DATA_PORT);
 101         outb_p(0xF3, IO_INDEX_PORT);
 102         outb_p(0x00, IO_DATA_PORT);     /* another setting is 0E for
 103                                            kbd/mouse/LED */
 104         outb_p(0xF4, IO_INDEX_PORT);
 105         outb_p(0x00, IO_DATA_PORT);
 106
 107         /* At last select device Aux1 (dev=7) and set GP16 as a
 108          * watchdog output. In test mode watch the bit 1 on F4 to
 109          * indicate "triggered"
 110          */
 111         if (!testmode) {
 112                 outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 113                 outb_p(0x07, IO_DATA_PORT);
 114                 outb_p(0xE6, IO_INDEX_PORT);
 115                 outb_p(0x08, IO_DATA_PORT);
 116         }
 117
 118         /* lock the SuperIO chip */
 119         outb_p(LOCK_DATA, IO_INDEX_PORT);
 120
 121         spin_unlock_irqrestore(&spinlock, flags);
 122         pr_info("activated\n");
 123
 124         return 0;
 125 }
 126
 127 /*
 128  * Stop the watchdog
 129  */
 130
 131 static int wdt977_stop(void)
 132 {
 133         unsigned long flags;
 134         spin_lock_irqsave(&spinlock, flags);
 135
 136         /* unlock the SuperIO chip */
 137         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 138         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 139
 140         /* select device Aux2 (device=8) and set watchdog regs F2,F3 and F4
 141         * F3 is reset to its default state
 142         * F4 can clear the TIMEOUT'ed state (bit 0) - back to default
 143         * We can not use GP17 as a PowerLed, as we use its usage as a RedLed
 144         */
 145         outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 146         outb_p(0x08, IO_DATA_PORT);
 147         outb_p(0xF2, IO_INDEX_PORT);
 148         outb_p(0xFF, IO_DATA_PORT);
 149         outb_p(0xF3, IO_INDEX_PORT);
 150         outb_p(0x00, IO_DATA_PORT);
 151         outb_p(0xF4, IO_INDEX_PORT);
 152         outb_p(0x00, IO_DATA_PORT);
 153         outb_p(0xF2, IO_INDEX_PORT);
 154         outb_p(0x00, IO_DATA_PORT);
 155
 156         /* at last select device Aux1 (dev=7) and set
 157            GP16 as a watchdog output */
 158         outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 159         outb_p(0x07, IO_DATA_PORT);
 160         outb_p(0xE6, IO_INDEX_PORT);
 161         outb_p(0x08, IO_DATA_PORT);
 162
 163         /* lock the SuperIO chip */
 164         outb_p(LOCK_DATA, IO_INDEX_PORT);
 165
 166         spin_unlock_irqrestore(&spinlock, flags);
 167         pr_info("shutdown\n");
 168
 169         return 0;
 170 }
 171
 172 /*
 173  * Send a keepalive ping to the watchdog
 174  * This is done by simply re-writing the timeout to reg. 0xF2
 175  */
 176
 177 static int wdt977_keepalive(void)
 178 {
 179         unsigned long flags;
 180         spin_lock_irqsave(&spinlock, flags);
 181
 182         /* unlock the SuperIO chip */
 183         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 184         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 185
 186         /* select device Aux2 (device=8) and kicks watchdog reg F2 */
 187         /* F2 has the timeout in minutes */
 188         outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 189         outb_p(0x08, IO_DATA_PORT);
 190         outb_p(0xF2, IO_INDEX_PORT);
 191         outb_p(timeoutM, IO_DATA_PORT);
 192
 193         /* lock the SuperIO chip */
 194         outb_p(LOCK_DATA, IO_INDEX_PORT);
 195         spin_unlock_irqrestore(&spinlock, flags);
 196
 197         return 0;
 198 }
 199
 200 /*
 201  * Set the watchdog timeout value
 202  */
 203
 204 static int wdt977_set_timeout(int t)
 205 {
 206         int tmrval;
 207
 208         /* convert seconds to minutes, rounding up */
 209         tmrval = (t + 59) / 60;
 210
 211         if (machine_is_netwinder()) {
 212                 /* we have a hw bug somewhere, so each 977 minute is actually
 213                  * only 30sec. This limits the max timeout to half of device
 214                  * max of 255 minutes...
 215                  */
 216                 tmrval += tmrval;
 217         }
 218
 219         if (tmrval < 1 || tmrval > 255)
 220                 return -EINVAL;
 221
 222         /* timeout is the timeout in seconds, timeoutM is
 223            the timeout in minutes) */
 224         timeout = t;
 225         timeoutM = tmrval;
 226         return 0;
 227 }
 228
 229 /*
 230  * Get the watchdog status
 231  */
 232
 233 static int wdt977_get_status(int *status)
 234 {
 235         int new_status;
 236         unsigned long flags;
 237
 238         spin_lock_irqsave(&spinlock, flags);
 239
 240         /* unlock the SuperIO chip */
 241         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 242         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 243
 244         /* select device Aux2 (device=8) and read watchdog reg F4 */
 245         outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 246         outb_p(0x08, IO_DATA_PORT);
 247         outb_p(0xF4, IO_INDEX_PORT);
 248         new_status = inb_p(IO_DATA_PORT);
 249
 250         /* lock the SuperIO chip */
 251         outb_p(LOCK_DATA, IO_INDEX_PORT);
 252
 253         spin_unlock_irqrestore(&spinlock, flags);
 254
 255         *status = 0;
 256         if (new_status & 1)
 257                 *status |= WDIOF_CARDRESET;
 258
 259         return 0;
 260 }
 261
 262
 263 /*
 264  *      /dev/watchdog handling
 265  */
 266
 267 static int wdt977_open(struct inode *inode, struct file *file)
 268 {
 269         /* If the watchdog is alive we don't need to start it again */
 270         if (test_and_set_bit(0, &timer_alive))
 271                 return -EBUSY;
 272
 273         if (nowayout)
 274                 __module_get(THIS_MODULE);
 275
 276         wdt977_start();
 277         return nonseekable_open(inode, file);
 278 }
 279
 280 static int wdt977_release(struct inode *inode, struct file *file)
 281 {
 282         /*
 283          *      Shut off the timer.
 284          *      Lock it in if it's a module and we set nowayout
 285          */
 286         if (expect_close == 42) {
 287                 wdt977_stop();
 288                 clear_bit(0, &timer_alive);
 289         } else {
 290                 wdt977_keepalive();
 291                 pr_crit("Unexpected close, not stopping watchdog!\n");
 292         }
 293         expect_close = 0;
 294         return 0;
 295 }
 296
 297
 298 /*
 299  *      wdt977_write:
 300  *      @file: file handle to the watchdog
 301  *      @buf: buffer to write (unused as data does not matter here
 302  *      @count: count of bytes
 303  *      @ppos: pointer to the position to write. No seeks allowed
 304  *
 305  *      A write to a watchdog device is defined as a keepalive signal. Any
 306  *      write of data will do, as we we don't define content meaning.
 307  */
 308
 309 static ssize_t wdt977_write(struct file *file, const char __user *buf,
 310                             size_t count, loff_t *ppos)
 311 {
 312         if (count) {
 313                 if (!nowayout) {
 314                         size_t i;
 315
 316                         /* In case it was set long ago */
 317                         expect_close = 0;
 318
 319                         for (i = 0; i != count; i++) {
 320                                 char c;
 321                                 if (get_user(c, buf + i))
 322                                         return -EFAULT;
 323                                 if (c == 'V')
 324                                         expect_close = 42;
 325                         }
 326                 }
 327
 328                 /* someone wrote to us, we should restart timer */
 329                 wdt977_keepalive();
 330         }
 331         return count;
 332 }
 333
 334 static const struct watchdog_info ident = {
 335         .options =              WDIOF_SETTIMEOUT |
 336                                 WDIOF_MAGICCLOSE |
 337                                 WDIOF_KEEPALIVEPING,
 338         .firmware_version =     1,
 339         .identity =             WATCHDOG_NAME,
 340 };
 341
 342 /*
 343  *      wdt977_ioctl:
 344  *      @inode: inode of the device
 345  *      @file: file handle to the device
 346  *      @cmd: watchdog command
 347  *      @arg: argument pointer
 348  *
 349  *      The watchdog API defines a common set of functions for all watchdogs
 350  *      according to their available features.
 351  */
 352
 353 static long wdt977_ioctl(struct file *file, unsigned int cmd,
 354                                                         unsigned long arg)
 355 {
 356         int status;
 357         int new_options, retval = -EINVAL;
 358         int new_timeout;
 359         union {
 360                 struct watchdog_info __user *ident;
 361                 int __user *i;
 362         } uarg;
 363
 364         uarg.i = (int __user *)arg;
 365
 366         switch (cmd) {
 367         case WDIOC_GETSUPPORT:
 368                 return copy_to_user(uarg.ident, &ident,
 369                         sizeof(ident)) ? -EFAULT : 0;
 370
 371         case WDIOC_GETSTATUS:
 372                 wdt977_get_status(&status);
 373                 return put_user(status, uarg.i);
 374
 375         case WDIOC_GETBOOTSTATUS:
 376                 return put_user(0, uarg.i);
 377
 378         case WDIOC_SETOPTIONS:
 379                 if (get_user(new_options, uarg.i))
 380                         return -EFAULT;
 381
 382                 if (new_options & WDIOS_DISABLECARD) {
 383                         wdt977_stop();
 384                         retval = 0;
 385                 }
 386
 387                 if (new_options & WDIOS_ENABLECARD) {
 388                         wdt977_start();
 389                         retval = 0;
 390                 }
 391
 392                 return retval;
 393
 394         case WDIOC_KEEPALIVE:
 395                 wdt977_keepalive();
 396                 return 0;
 397
 398         case WDIOC_SETTIMEOUT:
 399                 if (get_user(new_timeout, uarg.i))
 400                         return -EFAULT;
 401
 402                 if (wdt977_set_timeout(new_timeout))
 403                         return -EINVAL;
 404
 405                 wdt977_keepalive();
 406                 /* Fall */
 407
 408         case WDIOC_GETTIMEOUT:
 409                 return put_user(timeout, uarg.i);
 410
 411         default:
 412                 return -ENOTTY;
 413
 414         }
 415 }
 416
 417 static int wdt977_notify_sys(struct notifier_block *this, unsigned long code,
 418         void *unused)
 419 {
 420         if (code == SYS_DOWN || code == SYS_HALT)
 421                 wdt977_stop();
 422         return NOTIFY_DONE;
 423 }
 424
 425 static const struct file_operations wdt977_fops = {
 426         .owner          = THIS_MODULE,
 427         .llseek         = no_llseek,
 428         .write          = wdt977_write,
 429         .unlocked_ioctl = wdt977_ioctl,
 430         .open           = wdt977_open,
 431         .release        = wdt977_release,
 432 };
 433
 434 static struct miscdevice wdt977_miscdev = {
 435         .minor          = WATCHDOG_MINOR,
 436         .name           = "watchdog",
 437         .fops           = &wdt977_fops,
 438 };
 439
 440 static struct notifier_block wdt977_notifier = {
 441         .notifier_call = wdt977_notify_sys,
 442 };
 443
 444 static int __init wd977_init(void)
 445 {
 446         int rc;
 447
 448         pr_info("driver v%s\n", WATCHDOG_VERSION);
 449
 450         /* Check that the timeout value is within its range;
 451            if not reset to the default */
 452         if (wdt977_set_timeout(timeout)) {
 453                 wdt977_set_timeout(DEFAULT_TIMEOUT);
 454                 pr_info("timeout value must be 60 < timeout < 15300, using %d\n",
 455                         DEFAULT_TIMEOUT);
 456         }
 457
 458         /* on Netwinder the IOports are already reserved by
 459          * arch/arm/mach-footbridge/netwinder-hw.c
 460          */
 461         if (!machine_is_netwinder()) {
 462                 if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME)) {
 463                         pr_err("I/O address 0x%04x already in use\n",
 464                                IO_INDEX_PORT);
 465                         rc = -EIO;
 466                         goto err_out;
 467                 }
 468         }
 469
 470         rc = register_reboot_notifier(&wdt977_notifier);
 471         if (rc) {
 472                 pr_err("cannot register reboot notifier (err=%d)\n", rc);
 473                 goto err_out_region;
 474         }
 475
 476         rc = misc_register(&wdt977_miscdev);
 477         if (rc) {
 478                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 479                        wdt977_miscdev.minor, rc);
 480                 goto err_out_reboot;
 481         }
 482
 483         pr_info("initialized. timeout=%d sec (nowayout=%d, testmode=%i)\n",
 484                 timeout, nowayout, testmode);
 485
 486         return 0;
 487
 488 err_out_reboot:
 489         unregister_reboot_notifier(&wdt977_notifier);
 490 err_out_region:
 491         if (!machine_is_netwinder())
 492                 release_region(IO_INDEX_PORT, 2);
 493 err_out:
 494         return rc;
 495 }
 496
 497 static void __exit wd977_exit(void)
 498 {
 499         wdt977_stop();
 500         misc_deregister(&wdt977_miscdev);
 501         unregister_reboot_notifier(&wdt977_notifier);
 502         release_region(IO_INDEX_PORT, 2);
 503 }
 504
 505 module_init(wd977_init);
 506 module_exit(wd977_exit);
 507
 508 MODULE_AUTHOR("Woody Suwalski <woodys@xandros.com>");
 509 MODULE_DESCRIPTION("W83977AF Watchdog driver");
 510 MODULE_LICENSE("GPL");
 511 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);