git.oblomov.eu Git - linux-2.6/blob - drivers/watchdog/cpwd.c

   1 /* cpwd.c - driver implementation for hardware watchdog
   2  * timers found on Sun Microsystems CP1400 and CP1500 boards.
   3  *
   4  * This device supports both the generic Linux watchdog
   5  * interface and Solaris-compatible ioctls as best it is
   6  * able.
   7  *
   8  * NOTE:        CP1400 systems appear to have a defective intr_mask
   9  *                      register on the PLD, preventing the disabling of
  10  *                      timer interrupts.  We use a timer to periodically
  11  *                      reset 'stopped' watchdogs on affected platforms.
  12  *
  13  * Copyright (c) 2000 Eric Brower (ebrower@usa.net)
  14  * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/fs.h>
  20 #include <linux/errno.h>
  21 #include <linux/major.h>
  22 #include <linux/init.h>
  23 #include <linux/miscdevice.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/ioport.h>
  26 #include <linux/timer.h>
  27 #include <linux/smp_lock.h>
  28 #include <linux/io.h>
  29 #include <linux/of.h>
  30 #include <linux/of_device.h>
  31
  32 #include <asm/irq.h>
  33 #include <asm/uaccess.h>
  34
  35 #include <asm/watchdog.h>
  36
  37 #define DRIVER_NAME     "cpwd"
  38 #define PFX             DRIVER_NAME ": "
  39
  40 #define WD_OBPNAME      "watchdog"
  41 #define WD_BADMODEL     "SUNW,501-5336"
  42 #define WD_BTIMEOUT     (jiffies + (HZ * 1000))
  43 #define WD_BLIMIT       0xFFFF
  44
  45 #define WD0_MINOR       212
  46 #define WD1_MINOR       213
  47 #define WD2_MINOR       214
  48
  49 /* Internal driver definitions.  */
  50 #define WD0_ID                  0
  51 #define WD1_ID                  1
  52 #define WD2_ID                  2
  53 #define WD_NUMDEVS              3
  54
  55 #define WD_INTR_OFF             0
  56 #define WD_INTR_ON              1
  57
  58 #define WD_STAT_INIT    0x01    /* Watchdog timer is initialized        */
  59 #define WD_STAT_BSTOP   0x02    /* Watchdog timer is brokenstopped      */
  60 #define WD_STAT_SVCD    0x04    /* Watchdog interrupt occurred          */
  61
  62 /* Register value definitions
  63  */
  64 #define WD0_INTR_MASK   0x01    /* Watchdog device interrupt masks      */
  65 #define WD1_INTR_MASK   0x02
  66 #define WD2_INTR_MASK   0x04
  67
  68 #define WD_S_RUNNING    0x01    /* Watchdog device status running       */
  69 #define WD_S_EXPIRED    0x02    /* Watchdog device status expired       */
  70
  71 struct cpwd {
  72         void __iomem    *regs;
  73         spinlock_t      lock;
  74
  75         unsigned int    irq;
  76
  77         unsigned long   timeout;
  78         bool            enabled;
  79         bool            reboot;
  80         bool            broken;
  81         bool            initialized;
  82
  83         struct {
  84                 struct miscdevice       misc;
  85                 void __iomem            *regs;
  86                 u8                      intr_mask;
  87                 u8                      runstatus;
  88                 u16                     timeout;
  89         } devs[WD_NUMDEVS];
  90 };
  91
  92 static struct cpwd *cpwd_device;
  93
  94 /* Sun uses Altera PLD EPF8820ATC144-4
  95  * providing three hardware watchdogs:
  96  *
  97  *      1) RIC - sends an interrupt when triggered
  98  *      2) XIR - asserts XIR_B_RESET when triggered, resets CPU
  99  *      3) POR - asserts POR_B_RESET when triggered, resets CPU, backplane, board
 100  *
 101  *** Timer register block definition (struct wd_timer_regblk)
 102  *
 103  * dcntr and limit registers (halfword access):
 104  * -------------------
 105  * | 15 | ...| 1 | 0 |
 106  * -------------------
 107  * |-  counter val  -|
 108  * -------------------
 109  * dcntr -      Current 16-bit downcounter value.
 110  *                      When downcounter reaches '0' watchdog expires.
 111  *                      Reading this register resets downcounter with 'limit' value.
 112  * limit -      16-bit countdown value in 1/10th second increments.
 113  *                      Writing this register begins countdown with input value.
 114  *                      Reading from this register does not affect counter.
 115  * NOTES:       After watchdog reset, dcntr and limit contain '1'
 116  *
 117  * status register (byte access):
 118  * ---------------------------
 119  * | 7 | ... | 2 |  1  |  0  |
 120  * --------------+------------
 121  * |-   UNUSED  -| EXP | RUN |
 122  * ---------------------------
 123  * status-      Bit 0 - Watchdog is running
 124  *                      Bit 1 - Watchdog has expired
 125  *
 126  *** PLD register block definition (struct wd_pld_regblk)
 127  *
 128  * intr_mask register (byte access):
 129  * ---------------------------------
 130  * | 7 | ... | 3 |  2  |  1  |  0  |
 131  * +-------------+------------------
 132  * |-   UNUSED  -| WD3 | WD2 | WD1 |
 133  * ---------------------------------
 134  * WD3 -  1 == Interrupt disabled for watchdog 3
 135  * WD2 -  1 == Interrupt disabled for watchdog 2
 136  * WD1 -  1 == Interrupt disabled for watchdog 1
 137  *
 138  * pld_status register (byte access):
 139  * UNKNOWN, MAGICAL MYSTERY REGISTER
 140  *
 141  */
 142 #define WD_TIMER_REGSZ  16
 143 #define WD0_OFF         0
 144 #define WD1_OFF         (WD_TIMER_REGSZ * 1)
 145 #define WD2_OFF         (WD_TIMER_REGSZ * 2)
 146 #define PLD_OFF         (WD_TIMER_REGSZ * 3)
 147
 148 #define WD_DCNTR        0x00
 149 #define WD_LIMIT        0x04
 150 #define WD_STATUS       0x08
 151
 152 #define PLD_IMASK       (PLD_OFF + 0x00)
 153 #define PLD_STATUS      (PLD_OFF + 0x04)
 154
 155 static struct timer_list cpwd_timer;
 156
 157 static int wd0_timeout = 0;
 158 static int wd1_timeout = 0;
 159 static int wd2_timeout = 0;
 160
 161 module_param    (wd0_timeout, int, 0);
 162 MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs");
 163 module_param    (wd1_timeout, int, 0);
 164 MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs");
 165 module_param    (wd2_timeout, int, 0);
 166 MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs");
 167
 168 MODULE_AUTHOR("Eric Brower <ebrower@usa.net>");
 169 MODULE_DESCRIPTION("Hardware watchdog driver for Sun Microsystems CP1400/1500");
 170 MODULE_LICENSE("GPL");
 171 MODULE_SUPPORTED_DEVICE("watchdog");
 172
 173 static void cpwd_writew(u16 val, void __iomem *addr)
 174 {
 175         writew(cpu_to_le16(val), addr);
 176 }
 177 static u16 cpwd_readw(void __iomem *addr)
 178 {
 179         u16 val = readw(addr);
 180
 181         return le16_to_cpu(val);
 182 }
 183
 184 static void cpwd_writeb(u8 val, void __iomem *addr)
 185 {
 186         writeb(val, addr);
 187 }
 188
 189 static u8 cpwd_readb(void __iomem *addr)
 190 {
 191         return readb(addr);
 192 }
 193
 194 /* Enable or disable watchdog interrupts
 195  * Because of the CP1400 defect this should only be
 196  * called during initialzation or by wd_[start|stop]timer()
 197  *
 198  * index        - sub-device index, or -1 for 'all'
 199  * enable       - non-zero to enable interrupts, zero to disable
 200  */
 201 static void cpwd_toggleintr(struct cpwd *p, int index, int enable)
 202 {
 203         unsigned char curregs = cpwd_readb(p->regs + PLD_IMASK);
 204         unsigned char setregs =
 205                 (index == -1) ?
 206                 (WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) :
 207                 (p->devs[index].intr_mask);
 208
 209         if (enable == WD_INTR_ON)
 210                 curregs &= ~setregs;
 211         else
 212                 curregs |= setregs;
 213
 214         cpwd_writeb(curregs, p->regs + PLD_IMASK);
 215 }
 216
 217 /* Restarts timer with maximum limit value and
 218  * does not unset 'brokenstop' value.
 219  */
 220 static void cpwd_resetbrokentimer(struct cpwd *p, int index)
 221 {
 222         cpwd_toggleintr(p, index, WD_INTR_ON);
 223         cpwd_writew(WD_BLIMIT, p->devs[index].regs + WD_LIMIT);
 224 }
 225
 226 /* Timer method called to reset stopped watchdogs--
 227  * because of the PLD bug on CP1400, we cannot mask
 228  * interrupts within the PLD so me must continually
 229  * reset the timers ad infinitum.
 230  */
 231 static void cpwd_brokentimer(unsigned long data)
 232 {
 233         struct cpwd *p = (struct cpwd *) data;
 234         int id, tripped = 0;
 235
 236         /* kill a running timer instance, in case we
 237          * were called directly instead of by kernel timer
 238          */
 239         if (timer_pending(&cpwd_timer))
 240                 del_timer(&cpwd_timer);
 241
 242         for (id = 0; id < WD_NUMDEVS; id++) {
 243                 if (p->devs[id].runstatus & WD_STAT_BSTOP) {
 244                         ++tripped;
 245                         cpwd_resetbrokentimer(p, id);
 246                 }
 247         }
 248
 249         if (tripped) {
 250                 /* there is at least one timer brokenstopped-- reschedule */
 251                 cpwd_timer.expires = WD_BTIMEOUT;
 252                 add_timer(&cpwd_timer);
 253         }
 254 }
 255
 256 /* Reset countdown timer with 'limit' value and continue countdown.
 257  * This will not start a stopped timer.
 258  */
 259 static void cpwd_pingtimer(struct cpwd *p, int index)
 260 {
 261         if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING)
 262                 cpwd_readw(p->devs[index].regs + WD_DCNTR);
 263 }
 264
 265 /* Stop a running watchdog timer-- the timer actually keeps
 266  * running, but the interrupt is masked so that no action is
 267  * taken upon expiration.
 268  */
 269 static void cpwd_stoptimer(struct cpwd *p, int index)
 270 {
 271         if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING) {
 272                 cpwd_toggleintr(p, index, WD_INTR_OFF);
 273
 274                 if (p->broken) {
 275                         p->devs[index].runstatus |= WD_STAT_BSTOP;
 276                         cpwd_brokentimer((unsigned long) p);
 277                 }
 278         }
 279 }
 280
 281 /* Start a watchdog timer with the specified limit value
 282  * If the watchdog is running, it will be restarted with
 283  * the provided limit value.
 284  *
 285  * This function will enable interrupts on the specified
 286  * watchdog.
 287  */
 288 static void cpwd_starttimer(struct cpwd *p, int index)
 289 {
 290         if (p->broken)
 291                 p->devs[index].runstatus &= ~WD_STAT_BSTOP;
 292
 293         p->devs[index].runstatus &= ~WD_STAT_SVCD;
 294
 295         cpwd_writew(p->devs[index].timeout, p->devs[index].regs + WD_LIMIT);
 296         cpwd_toggleintr(p, index, WD_INTR_ON);
 297 }
 298
 299 static int cpwd_getstatus(struct cpwd *p, int index)
 300 {
 301         unsigned char stat = cpwd_readb(p->devs[index].regs + WD_STATUS);
 302         unsigned char intr = cpwd_readb(p->devs[index].regs + PLD_IMASK);
 303         unsigned char ret  = WD_STOPPED;
 304
 305         /* determine STOPPED */
 306         if (!stat)
 307                 return ret;
 308
 309         /* determine EXPIRED vs FREERUN vs RUNNING */
 310         else if (WD_S_EXPIRED & stat) {
 311                 ret = WD_EXPIRED;
 312         } else if(WD_S_RUNNING & stat) {
 313                 if (intr & p->devs[index].intr_mask) {
 314                         ret = WD_FREERUN;
 315                 } else {
 316                         /* Fudge WD_EXPIRED status for defective CP1400--
 317                          * IF timer is running
 318                          *      AND brokenstop is set
 319                          *      AND an interrupt has been serviced
 320                          * we are WD_EXPIRED.
 321                          *
 322                          * IF timer is running
 323                          *      AND brokenstop is set
 324                          *      AND no interrupt has been serviced
 325                          * we are WD_FREERUN.
 326                          */
 327                         if (p->broken &&
 328                             (p->devs[index].runstatus & WD_STAT_BSTOP)) {
 329                                 if (p->devs[index].runstatus & WD_STAT_SVCD) {
 330                                         ret = WD_EXPIRED;
 331                                 } else {
 332                                         /* we could as well pretend we are expired */
 333                                         ret = WD_FREERUN;
 334                                 }
 335                         } else {
 336                                 ret = WD_RUNNING;
 337                         }
 338                 }
 339         }
 340
 341         /* determine SERVICED */
 342         if (p->devs[index].runstatus & WD_STAT_SVCD)
 343                 ret |= WD_SERVICED;
 344
 345         return(ret);
 346 }
 347
 348 static irqreturn_t cpwd_interrupt(int irq, void *dev_id)
 349 {
 350         struct cpwd *p = dev_id;
 351
 352         /* Only WD0 will interrupt-- others are NMI and we won't
 353          * see them here....
 354          */
 355         spin_lock_irq(&p->lock);
 356
 357         cpwd_stoptimer(p, WD0_ID);
 358         p->devs[WD0_ID].runstatus |=  WD_STAT_SVCD;
 359
 360         spin_unlock_irq(&p->lock);
 361
 362         return IRQ_HANDLED;
 363 }
 364
 365 static int cpwd_open(struct inode *inode, struct file *f)
 366 {
 367         struct cpwd *p = cpwd_device;
 368
 369         lock_kernel();
 370         switch(iminor(inode)) {
 371                 case WD0_MINOR:
 372                 case WD1_MINOR:
 373                 case WD2_MINOR:
 374                         break;
 375
 376                 default:
 377                         unlock_kernel();
 378                         return -ENODEV;
 379         }
 380
 381         /* Register IRQ on first open of device */
 382         if (!p->initialized) {
 383                 if (request_irq(p->irq, &cpwd_interrupt,
 384                                 IRQF_SHARED, DRIVER_NAME, p)) {
 385                         printk(KERN_ERR PFX "Cannot register IRQ %d\n",
 386                                 p->irq);
 387                         unlock_kernel();
 388                         return -EBUSY;
 389                 }
 390                 p->initialized = true;
 391         }
 392
 393         unlock_kernel();
 394
 395         return nonseekable_open(inode, f);
 396 }
 397
 398 static int cpwd_release(struct inode *inode, struct file *file)
 399 {
 400         return 0;
 401 }
 402
 403 static int cpwd_ioctl(struct inode *inode, struct file *file,
 404                       unsigned int cmd, unsigned long arg)
 405 {
 406         static struct watchdog_info info = {
 407                 .options                = WDIOF_SETTIMEOUT,
 408                 .firmware_version       = 1,
 409                 .identity               = DRIVER_NAME,
 410         };
 411         void __user *argp = (void __user *)arg;
 412         int index = iminor(inode) - WD0_MINOR;
 413         struct cpwd *p = cpwd_device;
 414         int setopt = 0;
 415
 416         switch (cmd) {
 417         /* Generic Linux IOCTLs */
 418         case WDIOC_GETSUPPORT:
 419                 if (copy_to_user(argp, &info, sizeof(struct watchdog_info)))
 420                         return -EFAULT;
 421                 break;
 422
 423         case WDIOC_GETSTATUS:
 424         case WDIOC_GETBOOTSTATUS:
 425                 if (put_user(0, (int __user *)argp))
 426                         return -EFAULT;
 427                 break;
 428
 429         case WDIOC_KEEPALIVE:
 430                 cpwd_pingtimer(p, index);
 431                 break;
 432
 433         case WDIOC_SETOPTIONS:
 434                 if (copy_from_user(&setopt, argp, sizeof(unsigned int)))
 435                         return -EFAULT;
 436
 437                 if (setopt & WDIOS_DISABLECARD) {
 438                         if (p->enabled)
 439                                 return -EINVAL;
 440                         cpwd_stoptimer(p, index);
 441                 } else if (setopt & WDIOS_ENABLECARD) {
 442                         cpwd_starttimer(p, index);
 443                 } else {
 444                         return -EINVAL;
 445                 }
 446                 break;
 447
 448         /* Solaris-compatible IOCTLs */
 449         case WIOCGSTAT:
 450                 setopt = cpwd_getstatus(p, index);
 451                 if (copy_to_user(argp, &setopt, sizeof(unsigned int)))
 452                         return -EFAULT;
 453                 break;
 454
 455         case WIOCSTART:
 456                 cpwd_starttimer(p, index);
 457                 break;
 458
 459         case WIOCSTOP:
 460                 if (p->enabled)
 461                         return(-EINVAL);
 462
 463                 cpwd_stoptimer(p, index);
 464                 break;
 465
 466         default:
 467                 return -EINVAL;
 468         }
 469
 470         return 0;
 471 }
 472
 473 static long cpwd_compat_ioctl(struct file *file, unsigned int cmd,
 474                               unsigned long arg)
 475 {
 476         int rval = -ENOIOCTLCMD;
 477
 478         switch (cmd) {
 479         /* solaris ioctls are specific to this driver */
 480         case WIOCSTART:
 481         case WIOCSTOP:
 482         case WIOCGSTAT:
 483                 lock_kernel();
 484                 rval = cpwd_ioctl(file->f_path.dentry->d_inode, file, cmd, arg);
 485                 unlock_kernel();
 486                 break;
 487
 488         /* everything else is handled by the generic compat layer */
 489         default:
 490                 break;
 491         }
 492
 493         return rval;
 494 }
 495
 496 static ssize_t cpwd_write(struct file *file, const char __user *buf,
 497                           size_t count, loff_t *ppos)
 498 {
 499         struct inode *inode = file->f_path.dentry->d_inode;
 500         struct cpwd *p = cpwd_device;
 501         int index = iminor(inode);
 502
 503         if (count) {
 504                 cpwd_pingtimer(p, index);
 505                 return 1;
 506         }
 507
 508         return 0;
 509 }
 510
 511 static ssize_t cpwd_read(struct file * file, char __user *buffer,
 512                          size_t count, loff_t *ppos)
 513 {
 514         return -EINVAL;
 515 }
 516
 517 static const struct file_operations cpwd_fops = {
 518         .owner =        THIS_MODULE,
 519         .ioctl =        cpwd_ioctl,
 520         .compat_ioctl = cpwd_compat_ioctl,
 521         .open =         cpwd_open,
 522         .write =        cpwd_write,
 523         .read =         cpwd_read,
 524         .release =      cpwd_release,
 525 };
 526
 527 static int __devinit cpwd_probe(struct of_device *op,
 528                                 const struct of_device_id *match)
 529 {
 530         struct device_node *options;
 531         const char *str_prop;
 532         const void *prop_val;
 533         int i, err = -EINVAL;
 534         struct cpwd *p;
 535
 536         if (cpwd_device)
 537                 return -EINVAL;
 538
 539         p = kzalloc(sizeof(*p), GFP_KERNEL);
 540         err = -ENOMEM;
 541         if (!p) {
 542                 printk(KERN_ERR PFX "Unable to allocate struct cpwd.\n");
 543                 goto out;
 544         }
 545
 546         p->irq = op->irqs[0];
 547
 548         spin_lock_init(&p->lock);
 549
 550         p->regs = of_ioremap(&op->resource[0], 0,
 551                              4 * WD_TIMER_REGSZ, DRIVER_NAME);
 552         if (!p->regs) {
 553                 printk(KERN_ERR PFX "Unable to map registers.\n");
 554                 goto out_free;
 555         }
 556
 557         options = of_find_node_by_path("/options");
 558         err = -ENODEV;
 559         if (!options) {
 560                 printk(KERN_ERR PFX "Unable to find /options node.\n");
 561                 goto out_iounmap;
 562         }
 563
 564         prop_val = of_get_property(options, "watchdog-enable?", NULL);
 565         p->enabled = (prop_val ? true : false);
 566
 567         prop_val = of_get_property(options, "watchdog-reboot?", NULL);
 568         p->reboot = (prop_val ? true : false);
 569
 570         str_prop = of_get_property(options, "watchdog-timeout", NULL);
 571         if (str_prop)
 572                 p->timeout = simple_strtoul(str_prop, NULL, 10);
 573
 574         /* CP1400s seem to have broken PLD implementations-- the
 575          * interrupt_mask register cannot be written, so no timer
 576          * interrupts can be masked within the PLD.
 577          */
 578         str_prop = of_get_property(op->node, "model", NULL);
 579         p->broken = (str_prop && !strcmp(str_prop, WD_BADMODEL));
 580
 581         if (!p->enabled)
 582                 cpwd_toggleintr(p, -1, WD_INTR_OFF);
 583
 584         for (i = 0; i < WD_NUMDEVS; i++) {
 585                 static const char *cpwd_names[] = { "RIC", "XIR", "POR" };
 586                 static int *parms[] = { &wd0_timeout,
 587                                         &wd1_timeout,
 588                                         &wd2_timeout };
 589                 struct miscdevice *mp = &p->devs[i].misc;
 590
 591                 mp->minor = WD0_MINOR + i;
 592                 mp->name = cpwd_names[i];
 593                 mp->fops = &cpwd_fops;
 594
 595                 p->devs[i].regs = p->regs + (i * WD_TIMER_REGSZ);
 596                 p->devs[i].intr_mask = (WD0_INTR_MASK << i);
 597                 p->devs[i].runstatus &= ~WD_STAT_BSTOP;
 598                 p->devs[i].runstatus |= WD_STAT_INIT;
 599                 p->devs[i].timeout = p->timeout;
 600                 if (*parms[i])
 601                         p->devs[i].timeout = *parms[i];
 602
 603                 err = misc_register(&p->devs[i].misc);
 604                 if (err) {
 605                         printk(KERN_ERR "Could not register misc device for "
 606                                "dev %d\n", i);
 607                         goto out_unregister;
 608                 }
 609         }
 610
 611         if (p->broken) {
 612                 init_timer(&cpwd_timer);
 613                 cpwd_timer.function     = cpwd_brokentimer;
 614                 cpwd_timer.data         = (unsigned long) p;
 615                 cpwd_timer.expires      = WD_BTIMEOUT;
 616
 617                 printk(KERN_INFO PFX "PLD defect workaround enabled for "
 618                        "model " WD_BADMODEL ".\n");
 619         }
 620
 621         dev_set_drvdata(&op->dev, p);
 622         cpwd_device = p;
 623         err = 0;
 624
 625 out:
 626         return err;
 627
 628 out_unregister:
 629         for (i--; i >= 0; i--)
 630                 misc_deregister(&p->devs[i].misc);
 631
 632 out_iounmap:
 633         of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
 634
 635 out_free:
 636         kfree(p);
 637         goto out;
 638 }
 639
 640 static int __devexit cpwd_remove(struct of_device *op)
 641 {
 642         struct cpwd *p = dev_get_drvdata(&op->dev);
 643         int i;
 644
 645         for (i = 0; i < 4; i++) {
 646                 misc_deregister(&p->devs[i].misc);
 647
 648                 if (!p->enabled) {
 649                         cpwd_stoptimer(p, i);
 650                         if (p->devs[i].runstatus & WD_STAT_BSTOP)
 651                                 cpwd_resetbrokentimer(p, i);
 652                 }
 653         }
 654
 655         if (p->broken)
 656                 del_timer_sync(&cpwd_timer);
 657
 658         if (p->initialized)
 659                 free_irq(p->irq, p);
 660
 661         of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
 662         kfree(p);
 663
 664         cpwd_device = NULL;
 665
 666         return 0;
 667 }
 668
 669 static const struct of_device_id cpwd_match[] = {
 670         {
 671                 .name = "watchdog",
 672         },
 673         {},
 674 };
 675 MODULE_DEVICE_TABLE(of, cpwd_match);
 676
 677 static struct of_platform_driver cpwd_driver = {
 678         .name           = DRIVER_NAME,
 679         .match_table    = cpwd_match,
 680         .probe          = cpwd_probe,
 681         .remove         = __devexit_p(cpwd_remove),
 682 };
 683
 684 static int __init cpwd_init(void)
 685 {
 686         return of_register_driver(&cpwd_driver, &of_bus_type);
 687 }
 688
 689 static void __exit cpwd_exit(void)
 690 {
 691         of_unregister_driver(&cpwd_driver);
 692 }
 693
 694 module_init(cpwd_init);
 695 module_exit(cpwd_exit);