drivers/watchdog/w83977f_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      W83977F Watchdog Timer Driver for Winbond W83977F I/O Chip
   4  *
   5  *      (c) Copyright 2005  Jose Goncalves <jose.goncalves@inov.pt>
   6  *
   7  *      Based on w83877f_wdt.c by Scott Jennings,
   8  *           and wdt977.c by Woody Suwalski
   9  *
  10  *                      -----------------------
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/module.h>
  16 #include <linux/moduleparam.h>
  17 #include <linux/types.h>
  18 #include <linux/kernel.h>
  19 #include <linux/fs.h>
  20 #include <linux/miscdevice.h>
  21 #include <linux/init.h>
  22 #include <linux/ioport.h>
  23 #include <linux/watchdog.h>
  24 #include <linux/notifier.h>
  25 #include <linux/reboot.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/io.h>
  28
  29
  30 #define WATCHDOG_VERSION  "1.00"
  31 #define WATCHDOG_NAME     "W83977F WDT"
  32
  33 #define IO_INDEX_PORT     0x3F0
  34 #define IO_DATA_PORT      (IO_INDEX_PORT+1)
  35
  36 #define UNLOCK_DATA       0x87
  37 #define LOCK_DATA         0xAA
  38 #define DEVICE_REGISTER   0x07
  39
  40 #define DEFAULT_TIMEOUT   45            /* default timeout in seconds */
  41
  42 static  int timeout = DEFAULT_TIMEOUT;
  43 static  int timeoutW;                   /* timeout in watchdog counter units */
  44 static  unsigned long timer_alive;
  45 static  int testmode;
  46 static  char expect_close;
  47 static  DEFINE_SPINLOCK(spinlock);
  48
  49 module_param(timeout, int, 0);
  50 MODULE_PARM_DESC(timeout,
  51                 "Watchdog timeout in seconds (15..7635), default="
  52                                 __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 bool nowayout = WATCHDOG_NOWAYOUT;
  57 module_param(nowayout, bool, 0);
  58 MODULE_PARM_DESC(nowayout,
  59                 "Watchdog cannot be stopped once started (default="
  60                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  61
  62 /*
  63  * Start the watchdog
  64  */
  65
  66 static int wdt_start(void)
  67 {
  68         unsigned long flags;
  69
  70         spin_lock_irqsave(&spinlock, flags);
  71
  72         /* Unlock the SuperIO chip */
  73         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
  74         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
  75
  76         /*
  77          * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
  78          * F2 has the timeout in watchdog counter units.
  79          * F3 is set to enable watchdog LED blink at timeout.
  80          * F4 is used to just clear the TIMEOUT'ed state (bit 0).
  81          */
  82         outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
  83         outb_p(0x08, IO_DATA_PORT);
  84         outb_p(0xF2, IO_INDEX_PORT);
  85         outb_p(timeoutW, IO_DATA_PORT);
  86         outb_p(0xF3, IO_INDEX_PORT);
  87         outb_p(0x08, IO_DATA_PORT);
  88         outb_p(0xF4, IO_INDEX_PORT);
  89         outb_p(0x00, IO_DATA_PORT);
  90
  91         /* Set device Aux2 active */
  92         outb_p(0x30, IO_INDEX_PORT);
  93         outb_p(0x01, IO_DATA_PORT);
  94
  95         /*
  96          * Select device Aux1 (dev=7) to set GP16 as the watchdog output
  97          * (in reg E6) and GP13 as the watchdog LED output (in reg E3).
  98          * Map GP16 at pin 119.
  99          * In test mode watch the bit 0 on F4 to indicate "triggered" or
 100          * check watchdog LED on SBC.
 101          */
 102         outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 103         outb_p(0x07, IO_DATA_PORT);
 104         if (!testmode) {
 105                 unsigned pin_map;
 106
 107                 outb_p(0xE6, IO_INDEX_PORT);
 108                 outb_p(0x0A, IO_DATA_PORT);
 109                 outb_p(0x2C, IO_INDEX_PORT);
 110                 pin_map = inb_p(IO_DATA_PORT);
 111                 pin_map |= 0x10;
 112                 pin_map &= ~(0x20);
 113                 outb_p(0x2C, IO_INDEX_PORT);
 114                 outb_p(pin_map, IO_DATA_PORT);
 115         }
 116         outb_p(0xE3, IO_INDEX_PORT);
 117         outb_p(0x08, IO_DATA_PORT);
 118
 119         /* Set device Aux1 active */
 120         outb_p(0x30, IO_INDEX_PORT);
 121         outb_p(0x01, IO_DATA_PORT);
 122
 123         /* Lock the SuperIO chip */
 124         outb_p(LOCK_DATA, IO_INDEX_PORT);
 125
 126         spin_unlock_irqrestore(&spinlock, flags);
 127
 128         pr_info("activated\n");
 129
 130         return 0;
 131 }
 132
 133 /*
 134  * Stop the watchdog
 135  */
 136
 137 static int wdt_stop(void)
 138 {
 139         unsigned long flags;
 140
 141         spin_lock_irqsave(&spinlock, flags);
 142
 143         /* Unlock the SuperIO chip */
 144         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 145         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 146
 147         /*
 148          * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
 149          * F2 is reset to its default value (watchdog timer disabled).
 150          * F3 is reset to its default state.
 151          * F4 clears the TIMEOUT'ed state (bit 0) - back to default.
 152          */
 153         outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 154         outb_p(0x08, IO_DATA_PORT);
 155         outb_p(0xF2, IO_INDEX_PORT);
 156         outb_p(0xFF, IO_DATA_PORT);
 157         outb_p(0xF3, IO_INDEX_PORT);
 158         outb_p(0x00, IO_DATA_PORT);
 159         outb_p(0xF4, IO_INDEX_PORT);
 160         outb_p(0x00, IO_DATA_PORT);
 161         outb_p(0xF2, IO_INDEX_PORT);
 162         outb_p(0x00, IO_DATA_PORT);
 163
 164         /*
 165          * Select device Aux1 (dev=7) to set GP16 (in reg E6) and
 166          * Gp13 (in reg E3) as inputs.
 167          */
 168         outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 169         outb_p(0x07, IO_DATA_PORT);
 170         if (!testmode) {
 171                 outb_p(0xE6, IO_INDEX_PORT);
 172                 outb_p(0x01, IO_DATA_PORT);
 173         }
 174         outb_p(0xE3, IO_INDEX_PORT);
 175         outb_p(0x01, IO_DATA_PORT);
 176
 177         /* Lock the SuperIO chip */
 178         outb_p(LOCK_DATA, IO_INDEX_PORT);
 179
 180         spin_unlock_irqrestore(&spinlock, flags);
 181
 182         pr_info("shutdown\n");
 183
 184         return 0;
 185 }
 186
 187 /*
 188  * Send a keepalive ping to the watchdog
 189  * This is done by simply re-writing the timeout to reg. 0xF2
 190  */
 191
 192 static int wdt_keepalive(void)
 193 {
 194         unsigned long flags;
 195
 196         spin_lock_irqsave(&spinlock, flags);
 197
 198         /* Unlock the SuperIO chip */
 199         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 200         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 201
 202         /* Select device Aux2 (device=8) to kick watchdog reg F2 */
 203         outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 204         outb_p(0x08, IO_DATA_PORT);
 205         outb_p(0xF2, IO_INDEX_PORT);
 206         outb_p(timeoutW, IO_DATA_PORT);
 207
 208         /* Lock the SuperIO chip */
 209         outb_p(LOCK_DATA, IO_INDEX_PORT);
 210
 211         spin_unlock_irqrestore(&spinlock, flags);
 212
 213         return 0;
 214 }
 215
 216 /*
 217  * Set the watchdog timeout value
 218  */
 219
 220 static int wdt_set_timeout(int t)
 221 {
 222         unsigned int tmrval;
 223
 224         /*
 225          * Convert seconds to watchdog counter time units, rounding up.
 226          * On PCM-5335 watchdog units are 30 seconds/step with 15 sec startup
 227          * value. This information is supplied in the PCM-5335 manual and was
 228          * checked by me on a real board. This is a bit strange because W83977f
 229          * datasheet says counter unit is in minutes!
 230          */
 231         if (t < 15)
 232                 return -EINVAL;
 233
 234         tmrval = ((t + 15) + 29) / 30;
 235
 236         if (tmrval > 255)
 237                 return -EINVAL;
 238
 239         /*
 240          * timeout is the timeout in seconds,
 241          * timeoutW is the timeout in watchdog counter units.
 242          */
 243         timeoutW = tmrval;
 244         timeout = (timeoutW * 30) - 15;
 245         return 0;
 246 }
 247
 248 /*
 249  * Get the watchdog status
 250  */
 251
 252 static int wdt_get_status(int *status)
 253 {
 254         int new_status;
 255         unsigned long flags;
 256
 257         spin_lock_irqsave(&spinlock, flags);
 258
 259         /* Unlock the SuperIO chip */
 260         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 261         outb_p(UNLOCK_DATA, IO_INDEX_PORT);
 262
 263         /* Select device Aux2 (device=8) to read watchdog reg F4 */
 264         outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
 265         outb_p(0x08, IO_DATA_PORT);
 266         outb_p(0xF4, IO_INDEX_PORT);
 267         new_status = inb_p(IO_DATA_PORT);
 268
 269         /* Lock the SuperIO chip */
 270         outb_p(LOCK_DATA, IO_INDEX_PORT);
 271
 272         spin_unlock_irqrestore(&spinlock, flags);
 273
 274         *status = 0;
 275         if (new_status & 1)
 276                 *status |= WDIOF_CARDRESET;
 277
 278         return 0;
 279 }
 280
 281
 282 /*
 283  *      /dev/watchdog handling
 284  */
 285
 286 static int wdt_open(struct inode *inode, struct file *file)
 287 {
 288         /* If the watchdog is alive we don't need to start it again */
 289         if (test_and_set_bit(0, &timer_alive))
 290                 return -EBUSY;
 291
 292         if (nowayout)
 293                 __module_get(THIS_MODULE);
 294
 295         wdt_start();
 296         return stream_open(inode, file);
 297 }
 298
 299 static int wdt_release(struct inode *inode, struct file *file)
 300 {
 301         /*
 302          * Shut off the timer.
 303          * Lock it in if it's a module and we set nowayout
 304          */
 305         if (expect_close == 42) {
 306                 wdt_stop();
 307                 clear_bit(0, &timer_alive);
 308         } else {
 309                 wdt_keepalive();
 310                 pr_crit("unexpected close, not stopping watchdog!\n");
 311         }
 312         expect_close = 0;
 313         return 0;
 314 }
 315
 316 /*
 317  *      wdt_write:
 318  *      @file: file handle to the watchdog
 319  *      @buf: buffer to write (unused as data does not matter here
 320  *      @count: count of bytes
 321  *      @ppos: pointer to the position to write. No seeks allowed
 322  *
 323  *      A write to a watchdog device is defined as a keepalive signal. Any
 324  *      write of data will do, as we we don't define content meaning.
 325  */
 326
 327 static ssize_t wdt_write(struct file *file, const char __user *buf,
 328                             size_t count, loff_t *ppos)
 329 {
 330         /* See if we got the magic character 'V' and reload the timer */
 331         if (count) {
 332                 if (!nowayout) {
 333                         size_t ofs;
 334
 335                         /* note: just in case someone wrote the
 336                            magic character long ago */
 337                         expect_close = 0;
 338
 339                         /* scan to see whether or not we got the
 340                            magic character */
 341                         for (ofs = 0; ofs != count; ofs++) {
 342                                 char c;
 343                                 if (get_user(c, buf + ofs))
 344                                         return -EFAULT;
 345                                 if (c == 'V')
 346                                         expect_close = 42;
 347                         }
 348                 }
 349
 350                 /* someone wrote to us, we should restart timer */
 351                 wdt_keepalive();
 352         }
 353         return count;
 354 }
 355
 356 /*
 357  *      wdt_ioctl:
 358  *      @inode: inode of the device
 359  *      @file: file handle to the device
 360  *      @cmd: watchdog command
 361  *      @arg: argument pointer
 362  *
 363  *      The watchdog API defines a common set of functions for all watchdogs
 364  *      according to their available features.
 365  */
 366
 367 static const struct watchdog_info ident = {
 368         .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 369         .firmware_version =     1,
 370         .identity = WATCHDOG_NAME,
 371 };
 372
 373 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 374 {
 375         int status;
 376         int new_options, retval = -EINVAL;
 377         int new_timeout;
 378         union {
 379                 struct watchdog_info __user *ident;
 380                 int __user *i;
 381         } uarg;
 382
 383         uarg.i = (int __user *)arg;
 384
 385         switch (cmd) {
 386         case WDIOC_GETSUPPORT:
 387                 return copy_to_user(uarg.ident, &ident,
 388                                                 sizeof(ident)) ? -EFAULT : 0;
 389
 390         case WDIOC_GETSTATUS:
 391                 wdt_get_status(&status);
 392                 return put_user(status, uarg.i);
 393
 394         case WDIOC_GETBOOTSTATUS:
 395                 return put_user(0, uarg.i);
 396
 397         case WDIOC_SETOPTIONS:
 398                 if (get_user(new_options, uarg.i))
 399                         return -EFAULT;
 400
 401                 if (new_options & WDIOS_DISABLECARD) {
 402                         wdt_stop();
 403                         retval = 0;
 404                 }
 405
 406                 if (new_options & WDIOS_ENABLECARD) {
 407                         wdt_start();
 408                         retval = 0;
 409                 }
 410
 411                 return retval;
 412
 413         case WDIOC_KEEPALIVE:
 414                 wdt_keepalive();
 415                 return 0;
 416
 417         case WDIOC_SETTIMEOUT:
 418                 if (get_user(new_timeout, uarg.i))
 419                         return -EFAULT;
 420
 421                 if (wdt_set_timeout(new_timeout))
 422                         return -EINVAL;
 423
 424                 wdt_keepalive();
 425                 fallthrough;
 426
 427         case WDIOC_GETTIMEOUT:
 428                 return put_user(timeout, uarg.i);
 429
 430         default:
 431                 return -ENOTTY;
 432
 433         }
 434 }
 435
 436 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 437         void *unused)
 438 {
 439         if (code == SYS_DOWN || code == SYS_HALT)
 440                 wdt_stop();
 441         return NOTIFY_DONE;
 442 }
 443
 444 static const struct file_operations wdt_fops = {
 445         .owner          = THIS_MODULE,
 446         .llseek         = no_llseek,
 447         .write          = wdt_write,
 448         .unlocked_ioctl = wdt_ioctl,
 449         .compat_ioctl   = compat_ptr_ioctl,
 450         .open           = wdt_open,
 451         .release        = wdt_release,
 452 };
 453
 454 static struct miscdevice wdt_miscdev = {
 455         .minor          = WATCHDOG_MINOR,
 456         .name           = "watchdog",
 457         .fops           = &wdt_fops,
 458 };
 459
 460 static struct notifier_block wdt_notifier = {
 461         .notifier_call = wdt_notify_sys,
 462 };
 463
 464 static int __init w83977f_wdt_init(void)
 465 {
 466         int rc;
 467
 468         pr_info("driver v%s\n", WATCHDOG_VERSION);
 469
 470         /*
 471          * Check that the timeout value is within it's range;
 472          * if not reset to the default
 473          */
 474         if (wdt_set_timeout(timeout)) {
 475                 wdt_set_timeout(DEFAULT_TIMEOUT);
 476                 pr_info("timeout value must be 15 <= timeout <= 7635, using %d\n",
 477                         DEFAULT_TIMEOUT);
 478         }
 479
 480         if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME)) {
 481                 pr_err("I/O address 0x%04x already in use\n", IO_INDEX_PORT);
 482                 rc = -EIO;
 483                 goto err_out;
 484         }
 485
 486         rc = register_reboot_notifier(&wdt_notifier);
 487         if (rc) {
 488                 pr_err("cannot register reboot notifier (err=%d)\n", rc);
 489                 goto err_out_region;
 490         }
 491
 492         rc = misc_register(&wdt_miscdev);
 493         if (rc) {
 494                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 495                        wdt_miscdev.minor, rc);
 496                 goto err_out_reboot;
 497         }
 498
 499         pr_info("initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
 500                 timeout, nowayout, testmode);
 501
 502         return 0;
 503
 504 err_out_reboot:
 505         unregister_reboot_notifier(&wdt_notifier);
 506 err_out_region:
 507         release_region(IO_INDEX_PORT, 2);
 508 err_out:
 509         return rc;
 510 }
 511
 512 static void __exit w83977f_wdt_exit(void)
 513 {
 514         wdt_stop();
 515         misc_deregister(&wdt_miscdev);
 516         unregister_reboot_notifier(&wdt_notifier);
 517         release_region(IO_INDEX_PORT, 2);
 518 }
 519
 520 module_init(w83977f_wdt_init);
 521 module_exit(w83977f_wdt_exit);
 522
 523 MODULE_AUTHOR("Jose Goncalves <jose.goncalves@inov.pt>");
 524 MODULE_DESCRIPTION("Driver for watchdog timer in W83977F I/O chip");
 525 MODULE_LICENSE("GPL");