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/mutex.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 DEFINE_MUTEX(cpwd_mutex);
  93 static struct cpwd *cpwd_device;
  94
  95 /* Sun uses Altera PLD EPF8820ATC144-4
  96  * providing three hardware watchdogs:
  97  *
  98  * 1) RIC - sends an interrupt when triggered
  99  * 2) XIR - asserts XIR_B_RESET when triggered, resets CPU
 100  * 3) POR - asserts POR_B_RESET when triggered, resets CPU, backplane, board
 101  *
 102  *** Timer register block definition (struct wd_timer_regblk)
 103  *
 104  * dcntr and limit registers (halfword access):
 105  * -------------------
 106  * | 15 | ...| 1 | 0 |
 107  * -------------------
 108  * |-  counter val  -|
 109  * -------------------
 110  * dcntr -      Current 16-bit downcounter value.
 111  *                      When downcounter reaches '0' watchdog expires.
 112  *                      Reading this register resets downcounter with
 113  *                      'limit' value.
 114  * limit -      16-bit countdown value in 1/10th second increments.
 115  *                      Writing this register begins countdown with input value.
 116  *                      Reading from this register does not affect counter.
 117  * NOTES:       After watchdog reset, dcntr and limit contain '1'
 118  *
 119  * status register (byte access):
 120  * ---------------------------
 121  * | 7 | ... | 2 |  1  |  0  |
 122  * --------------+------------
 123  * |-   UNUSED  -| EXP | RUN |
 124  * ---------------------------
 125  * status-      Bit 0 - Watchdog is running
 126  *                      Bit 1 - Watchdog has expired
 127  *
 128  *** PLD register block definition (struct wd_pld_regblk)
 129  *
 130  * intr_mask register (byte access):
 131  * ---------------------------------
 132  * | 7 | ... | 3 |  2  |  1  |  0  |
 133  * +-------------+------------------
 134  * |-   UNUSED  -| WD3 | WD2 | WD1 |
 135  * ---------------------------------
 136  * WD3 -  1 == Interrupt disabled for watchdog 3
 137  * WD2 -  1 == Interrupt disabled for watchdog 2
 138  * WD1 -  1 == Interrupt disabled for watchdog 1
 139  *
 140  * pld_status register (byte access):
 141  * UNKNOWN, MAGICAL MYSTERY REGISTER
 142  *
 143  */
 144 #define WD_TIMER_REGSZ  16
 145 #define WD0_OFF         0
 146 #define WD1_OFF         (WD_TIMER_REGSZ * 1)
 147 #define WD2_OFF         (WD_TIMER_REGSZ * 2)
 148 #define PLD_OFF         (WD_TIMER_REGSZ * 3)
 149
 150 #define WD_DCNTR        0x00
 151 #define WD_LIMIT        0x04
 152 #define WD_STATUS       0x08
 153
 154 #define PLD_IMASK       (PLD_OFF + 0x00)
 155 #define PLD_STATUS      (PLD_OFF + 0x04)
 156
 157 static struct timer_list cpwd_timer;
 158
 159 static int wd0_timeout;
 160 static int wd1_timeout;
 161 static int wd2_timeout;
 162
 163 module_param(wd0_timeout, int, 0);
 164 MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs");
 165 module_param(wd1_timeout, int, 0);
 166 MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs");
 167 module_param(wd2_timeout, int, 0);
 168 MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs");
 169
 170 MODULE_AUTHOR("Eric Brower <ebrower@usa.net>");
 171 MODULE_DESCRIPTION("Hardware watchdog driver for Sun Microsystems CP1400/1500");
 172 MODULE_LICENSE("GPL");
 173 MODULE_SUPPORTED_DEVICE("watchdog");
 174
 175 static void cpwd_writew(u16 val, void __iomem *addr)
 176 {
 177         writew(cpu_to_le16(val), addr);
 178 }
 179 static u16 cpwd_readw(void __iomem *addr)
 180 {
 181         u16 val = readw(addr);
 182
 183         return le16_to_cpu(val);
 184 }
 185
 186 static void cpwd_writeb(u8 val, void __iomem *addr)
 187 {
 188         writeb(val, addr);
 189 }
 190
 191 static u8 cpwd_readb(void __iomem *addr)
 192 {
 193         return readb(addr);
 194 }
 195
 196 /* Enable or disable watchdog interrupts
 197  * Because of the CP1400 defect this should only be
 198  * called during initialzation or by wd_[start|stop]timer()
 199  *
 200  * index        - sub-device index, or -1 for 'all'
 201  * enable       - non-zero to enable interrupts, zero to disable
 202  */
 203 static void cpwd_toggleintr(struct cpwd *p, int index, int enable)
 204 {
 205         unsigned char curregs = cpwd_readb(p->regs + PLD_IMASK);
 206         unsigned char setregs =
 207                 (index == -1) ?
 208                 (WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) :
 209                 (p->devs[index].intr_mask);
 210
 211         if (enable == WD_INTR_ON)
 212                 curregs &= ~setregs;
 213         else
 214                 curregs |= setregs;
 215
 216         cpwd_writeb(curregs, p->regs + PLD_IMASK);
 217 }
 218
 219 /* Restarts timer with maximum limit value and
 220  * does not unset 'brokenstop' value.
 221  */
 222 static void cpwd_resetbrokentimer(struct cpwd *p, int index)
 223 {
 224         cpwd_toggleintr(p, index, WD_INTR_ON);
 225         cpwd_writew(WD_BLIMIT, p->devs[index].regs + WD_LIMIT);
 226 }
 227
 228 /* Timer method called to reset stopped watchdogs--
 229  * because of the PLD bug on CP1400, we cannot mask
 230  * interrupts within the PLD so me must continually
 231  * reset the timers ad infinitum.
 232  */
 233 static void cpwd_brokentimer(unsigned long data)
 234 {
 235         struct cpwd *p = (struct cpwd *) data;
 236         int id, tripped = 0;
 237
 238         /* kill a running timer instance, in case we
 239          * were called directly instead of by kernel timer
 240          */
 241         if (timer_pending(&cpwd_timer))
 242                 del_timer(&cpwd_timer);
 243
 244         for (id = 0; id < WD_NUMDEVS; id++) {
 245                 if (p->devs[id].runstatus & WD_STAT_BSTOP) {
 246                         ++tripped;
 247                         cpwd_resetbrokentimer(p, id);
 248                 }
 249         }
 250
 251         if (tripped) {
 252                 /* there is at least one timer brokenstopped-- reschedule */
 253                 cpwd_timer.expires = WD_BTIMEOUT;
 254                 add_timer(&cpwd_timer);
 255         }
 256 }
 257
 258 /* Reset countdown timer with 'limit' value and continue countdown.
 259  * This will not start a stopped timer.
 260  */
 261 static void cpwd_pingtimer(struct cpwd *p, int index)
 262 {
 263         if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING)
 264                 cpwd_readw(p->devs[index].regs + WD_DCNTR);
 265 }
 266
 267 /* Stop a running watchdog timer-- the timer actually keeps
 268  * running, but the interrupt is masked so that no action is
 269  * taken upon expiration.
 270  */
 271 static void cpwd_stoptimer(struct cpwd *p, int index)
 272 {
 273         if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING) {
 274                 cpwd_toggleintr(p, index, WD_INTR_OFF);
 275
 276                 if (p->broken) {
 277                         p->devs[index].runstatus |= WD_STAT_BSTOP;
 278                         cpwd_brokentimer((unsigned long) p);
 279                 }
 280         }
 281 }
 282
 283 /* Start a watchdog timer with the specified limit value
 284  * If the watchdog is running, it will be restarted with
 285  * the provided limit value.
 286  *
 287  * This function will enable interrupts on the specified
 288  * watchdog.
 289  */
 290 static void cpwd_starttimer(struct cpwd *p, int index)
 291 {
 292         if (p->broken)
 293                 p->devs[index].runstatus &= ~WD_STAT_BSTOP;
 294
 295         p->devs[index].runstatus &= ~WD_STAT_SVCD;
 296
 297         cpwd_writew(p->devs[index].timeout, p->devs[index].regs + WD_LIMIT);
 298         cpwd_toggleintr(p, index, WD_INTR_ON);
 299 }
 300
 301 static int cpwd_getstatus(struct cpwd *p, int index)
 302 {
 303         unsigned char stat = cpwd_readb(p->devs[index].regs + WD_STATUS);
 304         unsigned char intr = cpwd_readb(p->devs[index].regs + PLD_IMASK);
 305         unsigned char ret  = WD_STOPPED;
 306
 307         /* determine STOPPED */
 308         if (!stat)
 309                 return ret;
 310
 311         /* determine EXPIRED vs FREERUN vs RUNNING */
 312         else if (WD_S_EXPIRED & stat) {
 313                 ret = WD_EXPIRED;
 314         } else if (WD_S_RUNNING & stat) {
 315                 if (intr & p->devs[index].intr_mask) {
 316                         ret = WD_FREERUN;
 317                 } else {
 318                         /* Fudge WD_EXPIRED status for defective CP1400--
 319                          * IF timer is running
 320                          *      AND brokenstop is set
 321                          *      AND an interrupt has been serviced
 322                          * we are WD_EXPIRED.
 323                          *
 324                          * IF timer is running
 325                          *      AND brokenstop is set
 326                          *      AND no interrupt has been serviced
 327                          * we are WD_FREERUN.
 328                          */
 329                         if (p->broken &&
 330                             (p->devs[index].runstatus & WD_STAT_BSTOP)) {
 331                                 if (p->devs[index].runstatus & WD_STAT_SVCD) {
 332                                         ret = WD_EXPIRED;
 333                                 } else {
 334                                         /* we could as well pretend
 335                                          * we are expired */
 336                                         ret = WD_FREERUN;
 337                                 }
 338                         } else {
 339                                 ret = WD_RUNNING;
 340                         }
 341                 }
 342         }
 343
 344         /* determine SERVICED */
 345         if (p->devs[index].runstatus & WD_STAT_SVCD)
 346                 ret |= WD_SERVICED;
 347
 348         return ret;
 349 }
 350
 351 static irqreturn_t cpwd_interrupt(int irq, void *dev_id)
 352 {
 353         struct cpwd *p = dev_id;
 354
 355         /* Only WD0 will interrupt-- others are NMI and we won't
 356          * see them here....
 357          */
 358         spin_lock_irq(&p->lock);
 359
 360         cpwd_stoptimer(p, WD0_ID);
 361         p->devs[WD0_ID].runstatus |=  WD_STAT_SVCD;
 362
 363         spin_unlock_irq(&p->lock);
 364
 365         return IRQ_HANDLED;
 366 }
 367
 368 static int cpwd_open(struct inode *inode, struct file *f)
 369 {
 370         struct cpwd *p = cpwd_device;
 371
 372         mutex_lock(&cpwd_mutex);
 373         switch (iminor(inode)) {
 374         case WD0_MINOR:
 375         case WD1_MINOR:
 376         case WD2_MINOR:
 377                 break;
 378
 379         default:
 380                 mutex_unlock(&cpwd_mutex);
 381                 return -ENODEV;
 382         }
 383
 384         /* Register IRQ on first open of device */
 385         if (!p->initialized) {
 386                 if (request_irq(p->irq, &cpwd_interrupt,
 387                                 IRQF_SHARED, DRIVER_NAME, p)) {
 388                         printk(KERN_ERR PFX "Cannot register IRQ %d\n",
 389                                 p->irq);
 390                         mutex_unlock(&cpwd_mutex);
 391                         return -EBUSY;
 392                 }
 393                 p->initialized = true;
 394         }
 395
 396         mutex_unlock(&cpwd_mutex);
 397
 398         return nonseekable_open(inode, f);
 399 }
 400
 401 static int cpwd_release(struct inode *inode, struct file *file)
 402 {
 403         return 0;
 404 }
 405
 406 static long cpwd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 407 {
 408         static const struct watchdog_info info = {
 409                 .options                = WDIOF_SETTIMEOUT,
 410                 .firmware_version       = 1,
 411                 .identity               = DRIVER_NAME,
 412         };
 413         void __user *argp = (void __user *)arg;
 414         struct inode *inode = file->f_path.dentry->d_inode;
 415         int index = iminor(inode) - WD0_MINOR;
 416         struct cpwd *p = cpwd_device;
 417         int setopt = 0;
 418
 419         switch (cmd) {
 420         /* Generic Linux IOCTLs */
 421         case WDIOC_GETSUPPORT:
 422                 if (copy_to_user(argp, &info, sizeof(struct watchdog_info)))
 423                         return -EFAULT;
 424                 break;
 425
 426         case WDIOC_GETSTATUS:
 427         case WDIOC_GETBOOTSTATUS:
 428                 if (put_user(0, (int __user *)argp))
 429                         return -EFAULT;
 430                 break;
 431
 432         case WDIOC_KEEPALIVE:
 433                 cpwd_pingtimer(p, index);
 434                 break;
 435
 436         case WDIOC_SETOPTIONS:
 437                 if (copy_from_user(&setopt, argp, sizeof(unsigned int)))
 438                         return -EFAULT;
 439
 440                 if (setopt & WDIOS_DISABLECARD) {
 441                         if (p->enabled)
 442                                 return -EINVAL;
 443                         cpwd_stoptimer(p, index);
 444                 } else if (setopt & WDIOS_ENABLECARD) {
 445                         cpwd_starttimer(p, index);
 446                 } else {
 447                         return -EINVAL;
 448                 }
 449                 break;
 450
 451         /* Solaris-compatible IOCTLs */
 452         case WIOCGSTAT:
 453                 setopt = cpwd_getstatus(p, index);
 454                 if (copy_to_user(argp, &setopt, sizeof(unsigned int)))
 455                         return -EFAULT;
 456                 break;
 457
 458         case WIOCSTART:
 459                 cpwd_starttimer(p, index);
 460                 break;
 461
 462         case WIOCSTOP:
 463                 if (p->enabled)
 464                         return -EINVAL;
 465
 466                 cpwd_stoptimer(p, index);
 467                 break;
 468
 469         default:
 470                 return -EINVAL;
 471         }
 472
 473         return 0;
 474 }
 475
 476 static long cpwd_compat_ioctl(struct file *file, unsigned int cmd,
 477                               unsigned long arg)
 478 {
 479         int rval = -ENOIOCTLCMD;
 480
 481         switch (cmd) {
 482         /* solaris ioctls are specific to this driver */
 483         case WIOCSTART:
 484         case WIOCSTOP:
 485         case WIOCGSTAT:
 486                 mutex_lock(&cpwd_mutex);
 487                 rval = cpwd_ioctl(file, cmd, arg);
 488                 mutex_unlock(&cpwd_mutex);
 489                 break;
 490
 491         /* everything else is handled by the generic compat layer */
 492         default:
 493                 break;
 494         }
 495
 496         return rval;
 497 }
 498
 499 static ssize_t cpwd_write(struct file *file, const char __user *buf,
 500                           size_t count, loff_t *ppos)
 501 {
 502         struct inode *inode = file->f_path.dentry->d_inode;
 503         struct cpwd *p = cpwd_device;
 504         int index = iminor(inode);
 505
 506         if (count) {
 507                 cpwd_pingtimer(p, index);
 508                 return 1;
 509         }
 510
 511         return 0;
 512 }
 513
 514 static ssize_t cpwd_read(struct file *file, char __user *buffer,
 515                          size_t count, loff_t *ppos)
 516 {
 517         return -EINVAL;
 518 }
 519
 520 static const struct file_operations cpwd_fops = {
 521         .owner =                THIS_MODULE,
 522         .unlocked_ioctl =       cpwd_ioctl,
 523         .compat_ioctl =         cpwd_compat_ioctl,
 524         .open =                 cpwd_open,
 525         .write =                cpwd_write,
 526         .read =                 cpwd_read,
 527         .release =              cpwd_release,
 528         .llseek =               no_llseek,
 529 };
 530
 531 static int __devinit cpwd_probe(struct platform_device *op)
 532 {
 533         struct device_node *options;
 534         const char *str_prop;
 535         const void *prop_val;
 536         int i, err = -EINVAL;
 537         struct cpwd *p;
 538
 539         if (cpwd_device)
 540                 return -EINVAL;
 541
 542         p = kzalloc(sizeof(*p), GFP_KERNEL);
 543         err = -ENOMEM;
 544         if (!p) {
 545                 printk(KERN_ERR PFX "Unable to allocate struct cpwd.\n");
 546                 goto out;
 547         }
 548
 549         p->irq = op->archdata.irqs[0];
 550
 551         spin_lock_init(&p->lock);
 552
 553         p->regs = of_ioremap(&op->resource[0], 0,
 554                              4 * WD_TIMER_REGSZ, DRIVER_NAME);
 555         if (!p->regs) {
 556                 printk(KERN_ERR PFX "Unable to map registers.\n");
 557                 goto out_free;
 558         }
 559
 560         options = of_find_node_by_path("/options");
 561         err = -ENODEV;
 562         if (!options) {
 563                 printk(KERN_ERR PFX "Unable to find /options node.\n");
 564                 goto out_iounmap;
 565         }
 566
 567         prop_val = of_get_property(options, "watchdog-enable?", NULL);
 568         p->enabled = (prop_val ? true : false);
 569
 570         prop_val = of_get_property(options, "watchdog-reboot?", NULL);
 571         p->reboot = (prop_val ? true : false);
 572
 573         str_prop = of_get_property(options, "watchdog-timeout", NULL);
 574         if (str_prop)
 575                 p->timeout = simple_strtoul(str_prop, NULL, 10);
 576
 577         /* CP1400s seem to have broken PLD implementations-- the
 578          * interrupt_mask register cannot be written, so no timer
 579          * interrupts can be masked within the PLD.
 580          */
 581         str_prop = of_get_property(op->dev.of_node, "model", NULL);
 582         p->broken = (str_prop && !strcmp(str_prop, WD_BADMODEL));
 583
 584         if (!p->enabled)
 585                 cpwd_toggleintr(p, -1, WD_INTR_OFF);
 586
 587         for (i = 0; i < WD_NUMDEVS; i++) {
 588                 static const char *cpwd_names[] = { "RIC", "XIR", "POR" };
 589                 static int *parms[] = { &wd0_timeout,
 590                                         &wd1_timeout,
 591                                         &wd2_timeout };
 592                 struct miscdevice *mp = &p->devs[i].misc;
 593
 594                 mp->minor = WD0_MINOR + i;
 595                 mp->name = cpwd_names[i];
 596                 mp->fops = &cpwd_fops;
 597
 598                 p->devs[i].regs = p->regs + (i * WD_TIMER_REGSZ);
 599                 p->devs[i].intr_mask = (WD0_INTR_MASK << i);
 600                 p->devs[i].runstatus &= ~WD_STAT_BSTOP;
 601                 p->devs[i].runstatus |= WD_STAT_INIT;
 602                 p->devs[i].timeout = p->timeout;
 603                 if (*parms[i])
 604                         p->devs[i].timeout = *parms[i];
 605
 606                 err = misc_register(&p->devs[i].misc);
 607                 if (err) {
 608                         printk(KERN_ERR "Could not register misc device for "
 609                                "dev %d\n", i);
 610                         goto out_unregister;
 611                 }
 612         }
 613
 614         if (p->broken) {
 615                 init_timer(&cpwd_timer);
 616                 cpwd_timer.function     = cpwd_brokentimer;
 617                 cpwd_timer.data         = (unsigned long) p;
 618                 cpwd_timer.expires      = WD_BTIMEOUT;
 619
 620                 printk(KERN_INFO PFX "PLD defect workaround enabled for "
 621                        "model " WD_BADMODEL ".\n");
 622         }
 623
 624         dev_set_drvdata(&op->dev, p);
 625         cpwd_device = p;
 626         err = 0;
 627
 628 out:
 629         return err;
 630
 631 out_unregister:
 632         for (i--; i >= 0; i--)
 633                 misc_deregister(&p->devs[i].misc);
 634
 635 out_iounmap:
 636         of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
 637
 638 out_free:
 639         kfree(p);
 640         goto out;
 641 }
 642
 643 static int __devexit cpwd_remove(struct platform_device *op)
 644 {
 645         struct cpwd *p = dev_get_drvdata(&op->dev);
 646         int i;
 647
 648         for (i = 0; i < WD_NUMDEVS; i++) {
 649                 misc_deregister(&p->devs[i].misc);
 650
 651                 if (!p->enabled) {
 652                         cpwd_stoptimer(p, i);
 653                         if (p->devs[i].runstatus & WD_STAT_BSTOP)
 654                                 cpwd_resetbrokentimer(p, i);
 655                 }
 656         }
 657
 658         if (p->broken)
 659                 del_timer_sync(&cpwd_timer);
 660
 661         if (p->initialized)
 662                 free_irq(p->irq, p);
 663
 664         of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
 665         kfree(p);
 666
 667         cpwd_device = NULL;
 668
 669         return 0;
 670 }
 671
 672 static const struct of_device_id cpwd_match[] = {
 673         {
 674                 .name = "watchdog",
 675         },
 676         {},
 677 };
 678 MODULE_DEVICE_TABLE(of, cpwd_match);
 679
 680 static struct platform_driver cpwd_driver = {
 681         .driver = {
 682                 .name = DRIVER_NAME,
 683                 .owner = THIS_MODULE,
 684                 .of_match_table = cpwd_match,
 685         },
 686         .probe          = cpwd_probe,
 687         .remove         = __devexit_p(cpwd_remove),
 688 };
 689
 690 static int __init cpwd_init(void)
 691 {
 692         return platform_driver_register(&cpwd_driver);
 693 }
 694
 695 static void __exit cpwd_exit(void)
 696 {
 697         platform_driver_unregister(&cpwd_driver);
 698 }
 699
 700 module_init(cpwd_init);
 701 module_exit(cpwd_exit);