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