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