drivers/char/watchdog/w83977f_wdt.c

   1 /*
   2  *      W83977F Watchdog Timer Driver for Winbond W83977F I/O Chip
   3  *
   4  *      (c) Copyright 2005  Jose Goncalves <jose.goncalves@inov.pt>
   5  *
   6  *      Based on w83877f_wdt.c by Scott Jennings,
   7  *           and wdt977.c by Woody Suwalski
   8  *
   9  *                      -----------------------
  10  *
  11  *      This program is free software; you can redistribute it and/or
  12  *      modify it under the terms of the GNU General Public License
  13  *      as published by the Free Software Foundation; either version
  14  *      2 of the License, or (at your option) any later version.
  15  *
  16  */
  17
  18 #include <linux/module.h>
  19 #include <linux/moduleparam.h>
  20 #include <linux/types.h>
  21 #include <linux/kernel.h>
  22 #include <linux/fs.h>
  23 #include <linux/miscdevice.h>
  24 #include <linux/init.h>
  25 #include <linux/ioport.h>
  26 #include <linux/watchdog.h>
  27 #include <linux/notifier.h>
  28 #include <linux/reboot.h>
  29
  30 #include <asm/io.h>
  31 #include <asm/system.h>
  32 #include <asm/uaccess.h>
  33
  34 #define WATCHDOG_VERSION  "1.00"
  35 #define WATCHDOG_NAME     "W83977F WDT"
  36 #define PFX WATCHDOG_NAME ": "
  37 #define DRIVER_VERSION    WATCHDOG_NAME " driver, v" WATCHDOG_VERSION "\n"
  38
  39 #define IO_INDEX_PORT     0x3F0
  40 #define IO_DATA_PORT      (IO_INDEX_PORT+1)
  41
  42 #define UNLOCK_DATA       0x87
  43 #define LOCK_DATA         0xAA
  44 #define DEVICE_REGISTER   0x07
  45
  46 #define DEFAULT_TIMEOUT   45            /* default timeout in seconds */
  47
  48 static  int timeout = DEFAULT_TIMEOUT;
  49 static  int timeoutW;                   /* timeout in watchdog counter units */
  50 static  unsigned long timer_alive;
  51 static  int testmode;
  52 static  char expect_close;
  53 static  spinlock_t spinlock;
  54
  55 module_param(timeout, int, 0);
  56 MODULE_PARM_DESC(timeout,"Watchdog timeout in seconds (15..7635), default=" __MODULE_STRING(DEFAULT_TIMEOUT) ")");
  57 module_param(testmode, int, 0);
  58 MODULE_PARM_DESC(testmode,"Watchdog testmode (1 = no reboot), default=0");
  59
  60 static int nowayout = WATCHDOG_NOWAYOUT;
  61 module_param(nowayout, int, 0);
  62 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
  63
  64 /*
  65  * Start the watchdog
  66  */
  67
  68 static int wdt_start(void)
  69 {
  70         unsigned long flags;
  71
  72         spin_lock_irqsave(&spinlock, flags);
  73
  74         /* Unlock the SuperIO chip */
  75         outb_p(UNLOCK_DATA,IO_INDEX_PORT);
  76         outb_p(UNLOCK_DATA,IO_INDEX_PORT);
  77
  78         /*
  79          * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
  80          * F2 has the timeout in watchdog counter units.
  81          * F3 is set to enable watchdog LED blink at timeout.
  82          * F4 is used to just clear the TIMEOUT'ed state (bit 0).
  83          */
  84         outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
  85         outb_p(0x08,IO_DATA_PORT);
  86         outb_p(0xF2,IO_INDEX_PORT);
  87         outb_p(timeoutW,IO_DATA_PORT);
  88         outb_p(0xF3,IO_INDEX_PORT);
  89         outb_p(0x08,IO_DATA_PORT);
  90         outb_p(0xF4,IO_INDEX_PORT);
  91         outb_p(0x00,IO_DATA_PORT);
  92
  93         /* Set device Aux2 active */
  94         outb_p(0x30,IO_INDEX_PORT);
  95         outb_p(0x01,IO_DATA_PORT);
  96
  97         /*
  98          * Select device Aux1 (dev=7) to set GP16 as the watchdog output
  99          * (in reg E6) and GP13 as the watchdog LED output (in reg E3).
 100          * Map GP16 at pin 119.
 101          * In test mode watch the bit 0 on F4 to indicate "triggered" or
 102          * check watchdog LED on SBC.
 103          */
 104         outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
 105         outb_p(0x07,IO_DATA_PORT);
 106         if (!testmode)
 107         {
 108                 unsigned pin_map;
 109
 110                 outb_p(0xE6,IO_INDEX_PORT);
 111                 outb_p(0x0A,IO_DATA_PORT);
 112                 outb_p(0x2C,IO_INDEX_PORT);
 113                 pin_map = inb_p(IO_DATA_PORT);
 114                 pin_map |= 0x10;
 115                 pin_map &= ~(0x20);
 116                 outb_p(0x2C,IO_INDEX_PORT);
 117                 outb_p(pin_map,IO_DATA_PORT);
 118         }
 119         outb_p(0xE3,IO_INDEX_PORT);
 120         outb_p(0x08,IO_DATA_PORT);
 121
 122         /* Set device Aux1 active */
 123         outb_p(0x30,IO_INDEX_PORT);
 124         outb_p(0x01,IO_DATA_PORT);
 125
 126         /* Lock the SuperIO chip */
 127         outb_p(LOCK_DATA,IO_INDEX_PORT);
 128
 129         spin_unlock_irqrestore(&spinlock, flags);
 130
 131         printk(KERN_INFO PFX "activated.\n");
 132
 133         return 0;
 134 }
 135
 136 /*
 137  * Stop the watchdog
 138  */
 139
 140 static int wdt_stop(void)
 141 {
 142         unsigned long flags;
 143
 144         spin_lock_irqsave(&spinlock, flags);
 145
 146         /* Unlock the SuperIO chip */
 147         outb_p(UNLOCK_DATA,IO_INDEX_PORT);
 148         outb_p(UNLOCK_DATA,IO_INDEX_PORT);
 149
 150         /*
 151          * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
 152          * F2 is reset to its default value (watchdog timer disabled).
 153          * F3 is reset to its default state.
 154          * F4 clears the TIMEOUT'ed state (bit 0) - back to default.
 155          */
 156         outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
 157         outb_p(0x08,IO_DATA_PORT);
 158         outb_p(0xF2,IO_INDEX_PORT);
 159         outb_p(0xFF,IO_DATA_PORT);
 160         outb_p(0xF3,IO_INDEX_PORT);
 161         outb_p(0x00,IO_DATA_PORT);
 162         outb_p(0xF4,IO_INDEX_PORT);
 163         outb_p(0x00,IO_DATA_PORT);
 164         outb_p(0xF2,IO_INDEX_PORT);
 165         outb_p(0x00,IO_DATA_PORT);
 166
 167         /*
 168          * Select device Aux1 (dev=7) to set GP16 (in reg E6) and
 169          * Gp13 (in reg E3) as inputs.
 170          */
 171         outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
 172         outb_p(0x07,IO_DATA_PORT);
 173         if (!testmode)
 174         {
 175                 outb_p(0xE6,IO_INDEX_PORT);
 176                 outb_p(0x01,IO_DATA_PORT);
 177         }
 178         outb_p(0xE3,IO_INDEX_PORT);
 179         outb_p(0x01,IO_DATA_PORT);
 180
 181         /* Lock the SuperIO chip */
 182         outb_p(LOCK_DATA,IO_INDEX_PORT);
 183
 184         spin_unlock_irqrestore(&spinlock, flags);
 185
 186         printk(KERN_INFO PFX "shutdown.\n");
 187
 188         return 0;
 189 }
 190
 191 /*
 192  * Send a keepalive ping to the watchdog
 193  * This is done by simply re-writing the timeout to reg. 0xF2
 194  */
 195
 196 static int wdt_keepalive(void)
 197 {
 198         unsigned long flags;
 199
 200         spin_lock_irqsave(&spinlock, flags);
 201
 202         /* Unlock the SuperIO chip */
 203         outb_p(UNLOCK_DATA,IO_INDEX_PORT);
 204         outb_p(UNLOCK_DATA,IO_INDEX_PORT);
 205
 206         /* Select device Aux2 (device=8) to kick watchdog reg F2 */
 207         outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
 208         outb_p(0x08,IO_DATA_PORT);
 209         outb_p(0xF2,IO_INDEX_PORT);
 210         outb_p(timeoutW,IO_DATA_PORT);
 211
 212         /* Lock the SuperIO chip */
 213         outb_p(LOCK_DATA,IO_INDEX_PORT);
 214
 215         spin_unlock_irqrestore(&spinlock, flags);
 216
 217         return 0;
 218 }
 219
 220 /*
 221  * Set the watchdog timeout value
 222  */
 223
 224 static int wdt_set_timeout(int t)
 225 {
 226         int tmrval;
 227
 228         /*
 229          * Convert seconds to watchdog counter time units, rounding up.
 230          * On PCM-5335 watchdog units are 30 seconds/step with 15 sec startup
 231          * value. This information is supplied in the PCM-5335 manual and was
 232          * checked by me on a real board. This is a bit strange because W83977f
 233          * datasheet says counter unit is in minutes!
 234          */
 235         if (t < 15)
 236                 return -EINVAL;
 237
 238         tmrval = ((t + 15) + 29) / 30;
 239
 240         if (tmrval > 255)
 241                 return -EINVAL;
 242
 243         /*
 244          * timeout is the timeout in seconds,
 245          * timeoutW is the timeout in watchdog counter units.
 246          */
 247         timeoutW = tmrval;
 248         timeout = (timeoutW * 30) - 15;
 249         return 0;
 250 }
 251
 252 /*
 253  * Get the watchdog status
 254  */
 255
 256 static int wdt_get_status(int *status)
 257 {
 258         int new_status;
 259         unsigned long flags;
 260
 261         spin_lock_irqsave(&spinlock, flags);
 262
 263         /* Unlock the SuperIO chip */
 264         outb_p(UNLOCK_DATA,IO_INDEX_PORT);
 265         outb_p(UNLOCK_DATA,IO_INDEX_PORT);
 266
 267         /* Select device Aux2 (device=8) to read watchdog reg F4 */
 268         outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
 269         outb_p(0x08,IO_DATA_PORT);
 270         outb_p(0xF4,IO_INDEX_PORT);
 271         new_status = inb_p(IO_DATA_PORT);
 272
 273         /* Lock the SuperIO chip */
 274         outb_p(LOCK_DATA,IO_INDEX_PORT);
 275
 276         spin_unlock_irqrestore(&spinlock, flags);
 277
 278         *status = 0;
 279         if (new_status & 1)
 280                 *status |= WDIOF_CARDRESET;
 281
 282         return 0;
 283 }
 284
 285
 286 /*
 287  *      /dev/watchdog handling
 288  */
 289
 290 static int wdt_open(struct inode *inode, struct file *file)
 291 {
 292         /* If the watchdog is alive we don't need to start it again */
 293         if( test_and_set_bit(0, &timer_alive) )
 294                 return -EBUSY;
 295
 296         if (nowayout)
 297                 __module_get(THIS_MODULE);
 298
 299         wdt_start();
 300         return nonseekable_open(inode, file);
 301 }
 302
 303 static int wdt_release(struct inode *inode, struct file *file)
 304 {
 305         /*
 306          * Shut off the timer.
 307          * Lock it in if it's a module and we set nowayout
 308          */
 309         if (expect_close == 42)
 310         {
 311                 wdt_stop();
 312                 clear_bit(0, &timer_alive);
 313         } else {
 314                 wdt_keepalive();
 315                 printk(KERN_CRIT PFX "unexpected close, not stopping watchdog!\n");
 316         }
 317         expect_close = 0;
 318         return 0;
 319 }
 320
 321 /*
 322  *      wdt_write:
 323  *      @file: file handle to the watchdog
 324  *      @buf: buffer to write (unused as data does not matter here
 325  *      @count: count of bytes
 326  *      @ppos: pointer to the position to write. No seeks allowed
 327  *
 328  *      A write to a watchdog device is defined as a keepalive signal. Any
 329  *      write of data will do, as we we don't define content meaning.
 330  */
 331
 332 static ssize_t wdt_write(struct file *file, const char __user *buf,
 333                             size_t count, loff_t *ppos)
 334 {
 335         /* See if we got the magic character 'V' and reload the timer */
 336         if(count)
 337         {
 338                 if (!nowayout)
 339                 {
 340                         size_t ofs;
 341
 342                         /* note: just in case someone wrote the magic character long ago */
 343                         expect_close = 0;
 344
 345                         /* scan to see whether or not we got the magic character */
 346                         for(ofs = 0; ofs != count; ofs++)
 347                         {
 348                                 char c;
 349                                 if (get_user(c, buf + ofs))
 350                                         return -EFAULT;
 351                                 if (c == 'V') {
 352                                         expect_close = 42;
 353                                 }
 354                         }
 355                 }
 356
 357                 /* someone wrote to us, we should restart timer */
 358                 wdt_keepalive();
 359         }
 360         return count;
 361 }
 362
 363 /*
 364  *      wdt_ioctl:
 365  *      @inode: inode of the device
 366  *      @file: file handle to the device
 367  *      @cmd: watchdog command
 368  *      @arg: argument pointer
 369  *
 370  *      The watchdog API defines a common set of functions for all watchdogs
 371  *      according to their available features.
 372  */
 373
 374 static struct watchdog_info ident = {
 375         .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 376         .firmware_version =     1,
 377         .identity = WATCHDOG_NAME,
 378 };
 379
 380 static int wdt_ioctl(struct inode *inode, struct file *file,
 381         unsigned int cmd, unsigned long arg)
 382 {
 383         int status;
 384         int new_options, retval = -EINVAL;
 385         int new_timeout;
 386         union {
 387                 struct watchdog_info __user *ident;
 388                 int __user *i;
 389         } uarg;
 390
 391         uarg.i = (int __user *)arg;
 392
 393         switch(cmd)
 394         {
 395         default:
 396                 return -ENOIOCTLCMD;
 397
 398         case WDIOC_GETSUPPORT:
 399                 return copy_to_user(uarg.ident, &ident, sizeof(ident)) ? -EFAULT : 0;
 400
 401         case WDIOC_GETSTATUS:
 402                 wdt_get_status(&status);
 403                 return put_user(status, uarg.i);
 404
 405         case WDIOC_GETBOOTSTATUS:
 406                 return put_user(0, uarg.i);
 407
 408         case WDIOC_KEEPALIVE:
 409                 wdt_keepalive();
 410                 return 0;
 411
 412         case WDIOC_SETOPTIONS:
 413                 if (get_user (new_options, uarg.i))
 414                         return -EFAULT;
 415
 416                 if (new_options & WDIOS_DISABLECARD) {
 417                         wdt_stop();
 418                         retval = 0;
 419                 }
 420
 421                 if (new_options & WDIOS_ENABLECARD) {
 422                         wdt_start();
 423                         retval = 0;
 424                 }
 425
 426                 return retval;
 427
 428         case WDIOC_SETTIMEOUT:
 429                 if (get_user(new_timeout, uarg.i))
 430                         return -EFAULT;
 431
 432                 if (wdt_set_timeout(new_timeout))
 433                     return -EINVAL;
 434
 435                 wdt_keepalive();
 436                 /* Fall */
 437
 438         case WDIOC_GETTIMEOUT:
 439                 return put_user(timeout, uarg.i);
 440
 441         }
 442 }
 443
 444 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 445         void *unused)
 446 {
 447         if (code==SYS_DOWN || code==SYS_HALT)
 448                 wdt_stop();
 449         return NOTIFY_DONE;
 450 }
 451
 452 static const struct file_operations wdt_fops=
 453 {
 454         .owner          = THIS_MODULE,
 455         .llseek         = no_llseek,
 456         .write          = wdt_write,
 457         .ioctl          = wdt_ioctl,
 458         .open           = wdt_open,
 459         .release        = wdt_release,
 460 };
 461
 462 static struct miscdevice wdt_miscdev=
 463 {
 464         .minor          = WATCHDOG_MINOR,
 465         .name           = "watchdog",
 466         .fops           = &wdt_fops,
 467 };
 468
 469 static struct notifier_block wdt_notifier = {
 470         .notifier_call = wdt_notify_sys,
 471 };
 472
 473 static int __init w83977f_wdt_init(void)
 474 {
 475         int rc;
 476
 477         printk(KERN_INFO PFX DRIVER_VERSION);
 478
 479         spin_lock_init(&spinlock);
 480
 481         /*
 482          * Check that the timeout value is within it's range ;
 483          * if not reset to the default
 484          */
 485         if (wdt_set_timeout(timeout)) {
 486                 wdt_set_timeout(DEFAULT_TIMEOUT);
 487                 printk(KERN_INFO PFX "timeout value must be 15<=timeout<=7635, using %d\n",
 488                         DEFAULT_TIMEOUT);
 489         }
 490
 491         if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME))
 492         {
 493                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
 494                         IO_INDEX_PORT);
 495                 rc = -EIO;
 496                 goto err_out;
 497         }
 498
 499         rc = misc_register(&wdt_miscdev);
 500         if (rc)
 501         {
 502                 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 503                         wdt_miscdev.minor, rc);
 504                 goto err_out_region;
 505         }
 506
 507         rc = register_reboot_notifier(&wdt_notifier);
 508         if (rc)
 509         {
 510                 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 511                         rc);
 512                 goto err_out_miscdev;
 513         }
 514
 515         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
 516                 timeout, nowayout, testmode);
 517
 518         return 0;
 519
 520 err_out_miscdev:
 521         misc_deregister(&wdt_miscdev);
 522 err_out_region:
 523         release_region(IO_INDEX_PORT,2);
 524 err_out:
 525         return rc;
 526 }
 527
 528 static void __exit w83977f_wdt_exit(void)
 529 {
 530         wdt_stop();
 531         misc_deregister(&wdt_miscdev);
 532         unregister_reboot_notifier(&wdt_notifier);
 533         release_region(IO_INDEX_PORT,2);
 534 }
 535
 536 module_init(w83977f_wdt_init);
 537 module_exit(w83977f_wdt_exit);
 538
 539 MODULE_AUTHOR("Jose Goncalves <jose.goncalves@inov.pt>");
 540 MODULE_DESCRIPTION("Driver for watchdog timer in W83977F I/O chip");
 541 MODULE_LICENSE("GPL");
 542 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);