git.oblomov.eu Git - linux-2.6/blob - drivers/sbus/char/cpwatchdog.c

   1 /* cpwatchdog.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  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/fs.h>
  19 #include <linux/errno.h>
  20 #include <linux/major.h>
  21 #include <linux/init.h>
  22 #include <linux/miscdevice.h>
  23 #include <linux/sched.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/ioport.h>
  26 #include <linux/timer.h>
  27 #include <linux/smp_lock.h>
  28 #include <asm/irq.h>
  29 #include <asm/ebus.h>
  30 #include <asm/oplib.h>
  31 #include <asm/uaccess.h>
  32
  33 #include <asm/watchdog.h>
  34
  35 #define WD_OBPNAME      "watchdog"
  36 #define WD_BADMODEL "SUNW,501-5336"
  37 #define WD_BTIMEOUT     (jiffies + (HZ * 1000))
  38 #define WD_BLIMIT       0xFFFF
  39
  40 #define WD0_DEVNAME "watchdog0"
  41 #define WD1_DEVNAME "watchdog1"
  42 #define WD2_DEVNAME "watchdog2"
  43
  44 #define WD0_MINOR       212
  45 #define WD1_MINOR       213
  46 #define WD2_MINOR       214
  47
  48
  49 /* Internal driver definitions
  50  */
  51 #define WD0_ID                  0               /* Watchdog0                                            */
  52 #define WD1_ID                  1               /* Watchdog1                                            */
  53 #define WD2_ID                  2               /* Watchdog2                                            */
  54 #define WD_NUMDEVS              3               /* Device contains 3 timers                     */
  55
  56 #define WD_INTR_OFF             0               /* Interrupt disable value                      */
  57 #define WD_INTR_ON              1               /* Interrupt enable value                       */
  58
  59 #define WD_STAT_INIT    0x01    /* Watchdog timer is initialized        */
  60 #define WD_STAT_BSTOP   0x02    /* Watchdog timer is brokenstopped      */
  61 #define WD_STAT_SVCD    0x04    /* Watchdog interrupt occurred          */
  62
  63 /* Register value definitions
  64  */
  65 #define WD0_INTR_MASK   0x01    /* Watchdog device interrupt masks      */
  66 #define WD1_INTR_MASK   0x02
  67 #define WD2_INTR_MASK   0x04
  68
  69 #define WD_S_RUNNING    0x01    /* Watchdog device status running       */
  70 #define WD_S_EXPIRED    0x02    /* Watchdog device status expired       */
  71
  72 /* Sun uses Altera PLD EPF8820ATC144-4
  73  * providing three hardware watchdogs:
  74  *
  75  *      1) RIC - sends an interrupt when triggered
  76  *      2) XIR - asserts XIR_B_RESET when triggered, resets CPU
  77  *      3) POR - asserts POR_B_RESET when triggered, resets CPU, backplane, board
  78  *
  79  *** Timer register block definition (struct wd_timer_regblk)
  80  *
  81  * dcntr and limit registers (halfword access):
  82  * -------------------
  83  * | 15 | ...| 1 | 0 |
  84  * -------------------
  85  * |-  counter val  -|
  86  * -------------------
  87  * dcntr -      Current 16-bit downcounter value.
  88  *                      When downcounter reaches '0' watchdog expires.
  89  *                      Reading this register resets downcounter with 'limit' value.
  90  * limit -      16-bit countdown value in 1/10th second increments.
  91  *                      Writing this register begins countdown with input value.
  92  *                      Reading from this register does not affect counter.
  93  * NOTES:       After watchdog reset, dcntr and limit contain '1'
  94  *
  95  * status register (byte access):
  96  * ---------------------------
  97  * | 7 | ... | 2 |  1  |  0  |
  98  * --------------+------------
  99  * |-   UNUSED  -| EXP | RUN |
 100  * ---------------------------
 101  * status-      Bit 0 - Watchdog is running
 102  *                      Bit 1 - Watchdog has expired
 103  *
 104  *** PLD register block definition (struct wd_pld_regblk)
 105  *
 106  * intr_mask register (byte access):
 107  * ---------------------------------
 108  * | 7 | ... | 3 |  2  |  1  |  0  |
 109  * +-------------+------------------
 110  * |-   UNUSED  -| WD3 | WD2 | WD1 |
 111  * ---------------------------------
 112  * WD3 -  1 == Interrupt disabled for watchdog 3
 113  * WD2 -  1 == Interrupt disabled for watchdog 2
 114  * WD1 -  1 == Interrupt disabled for watchdog 1
 115  *
 116  * pld_status register (byte access):
 117  * UNKNOWN, MAGICAL MYSTERY REGISTER
 118  *
 119  */
 120 #define WD_TIMER_REGSZ  16
 121 #define WD0_OFF         0
 122 #define WD1_OFF         (WD_TIMER_REGSZ * 1)
 123 #define WD2_OFF         (WD_TIMER_REGSZ * 2)
 124 #define PLD_OFF         (WD_TIMER_REGSZ * 3)
 125
 126 #define WD_DCNTR        0x00
 127 #define WD_LIMIT        0x04
 128 #define WD_STATUS       0x08
 129
 130 #define PLD_IMASK       (PLD_OFF + 0x00)
 131 #define PLD_STATUS      (PLD_OFF + 0x04)
 132
 133 /* Individual timer structure
 134  */
 135 struct wd_timer {
 136         __u16                   timeout;
 137         __u8                    intr_mask;
 138         unsigned char           runstatus;
 139         void __iomem            *regs;
 140 };
 141
 142 /* Device structure
 143  */
 144 struct wd_device {
 145         int                             irq;
 146         spinlock_t              lock;
 147         unsigned char   isbaddoggie;    /* defective PLD */
 148         unsigned char   opt_enable;
 149         unsigned char   opt_reboot;
 150         unsigned short  opt_timeout;
 151         unsigned char   initialized;
 152         struct wd_timer watchdog[WD_NUMDEVS];
 153         void __iomem    *regs;
 154 };
 155
 156 static struct wd_device wd_dev = {
 157                 0, SPIN_LOCK_UNLOCKED, 0, 0, 0, 0,
 158 };
 159
 160 static struct timer_list wd_timer;
 161
 162 static int wd0_timeout = 0;
 163 static int wd1_timeout = 0;
 164 static int wd2_timeout = 0;
 165
 166 #ifdef MODULE
 167 module_param    (wd0_timeout, int, 0);
 168 MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs");
 169 module_param    (wd1_timeout, int, 0);
 170 MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs");
 171 module_param    (wd2_timeout, int, 0);
 172 MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs");
 173
 174 MODULE_AUTHOR
 175         ("Eric Brower <ebrower@usa.net>");
 176 MODULE_DESCRIPTION
 177         ("Hardware watchdog driver for Sun Microsystems CP1400/1500");
 178 MODULE_LICENSE("GPL");
 179 MODULE_SUPPORTED_DEVICE
 180         ("watchdog");
 181 #endif /* ifdef MODULE */
 182
 183 /* Forward declarations of internal methods
 184  */
 185 #ifdef WD_DEBUG
 186 static void wd_dumpregs(void);
 187 #endif
 188 static irqreturn_t wd_interrupt(int irq, void *dev_id);
 189 static void wd_toggleintr(struct wd_timer* pTimer, int enable);
 190 static void wd_pingtimer(struct wd_timer* pTimer);
 191 static void wd_starttimer(struct wd_timer* pTimer);
 192 static void wd_resetbrokentimer(struct wd_timer* pTimer);
 193 static void wd_stoptimer(struct wd_timer* pTimer);
 194 static void wd_brokentimer(unsigned long data);
 195 static int  wd_getstatus(struct wd_timer* pTimer);
 196
 197 /* PLD expects words to be written in LSB format,
 198  * so we must flip all words prior to writing them to regs
 199  */
 200 static inline unsigned short flip_word(unsigned short word)
 201 {
 202         return ((word & 0xff) << 8) | ((word >> 8) & 0xff);
 203 }
 204
 205 #define wd_writew(val, addr)    (writew(flip_word(val), addr))
 206 #define wd_readw(addr)                  (flip_word(readw(addr)))
 207 #define wd_writeb(val, addr)    (writeb(val, addr))
 208 #define wd_readb(addr)                  (readb(addr))
 209
 210
 211 /* CP1400s seem to have broken PLD implementations--
 212  * the interrupt_mask register cannot be written, so
 213  * no timer interrupts can be masked within the PLD.
 214  */
 215 static inline int wd_isbroken(void)
 216 {
 217         /* we could test this by read/write/read/restore
 218          * on the interrupt mask register only if OBP
 219          * 'watchdog-enable?' == FALSE, but it seems
 220          * ubiquitous on CP1400s
 221          */
 222         char val[32];
 223         prom_getproperty(prom_root_node, "model", val, sizeof(val));
 224         return((!strcmp(val, WD_BADMODEL)) ? 1 : 0);
 225 }
 226
 227 /* Retrieve watchdog-enable? option from OBP
 228  * Returns 0 if false, 1 if true
 229  */
 230 static inline int wd_opt_enable(void)
 231 {
 232         int opt_node;
 233
 234         opt_node = prom_getchild(prom_root_node);
 235         opt_node = prom_searchsiblings(opt_node, "options");
 236         return((-1 == prom_getint(opt_node, "watchdog-enable?")) ? 0 : 1);
 237 }
 238
 239 /* Retrieve watchdog-reboot? option from OBP
 240  * Returns 0 if false, 1 if true
 241  */
 242 static inline int wd_opt_reboot(void)
 243 {
 244         int opt_node;
 245
 246         opt_node = prom_getchild(prom_root_node);
 247         opt_node = prom_searchsiblings(opt_node, "options");
 248         return((-1 == prom_getint(opt_node, "watchdog-reboot?")) ? 0 : 1);
 249 }
 250
 251 /* Retrieve watchdog-timeout option from OBP
 252  * Returns OBP value, or 0 if not located
 253  */
 254 static inline int wd_opt_timeout(void)
 255 {
 256         int opt_node;
 257         char value[32];
 258         char *p = value;
 259
 260         opt_node = prom_getchild(prom_root_node);
 261         opt_node = prom_searchsiblings(opt_node, "options");
 262         opt_node = prom_getproperty(opt_node,
 263                                                                 "watchdog-timeout",
 264                                                                 value,
 265                                                                 sizeof(value));
 266         if(-1 != opt_node) {
 267                 /* atoi implementation */
 268                 for(opt_node = 0; /* nop */; p++) {
 269                         if(*p >= '0' && *p <= '9') {
 270                                 opt_node = (10*opt_node)+(*p-'0');
 271                         }
 272                         else {
 273                                 break;
 274                         }
 275                 }
 276         }
 277         return((-1 == opt_node) ? (0) : (opt_node));
 278 }
 279
 280 static int wd_open(struct inode *inode, struct file *f)
 281 {
 282         switch(iminor(inode))
 283         {
 284                 case WD0_MINOR:
 285                         f->private_data = &wd_dev.watchdog[WD0_ID];
 286                         break;
 287                 case WD1_MINOR:
 288                         f->private_data = &wd_dev.watchdog[WD1_ID];
 289                         break;
 290                 case WD2_MINOR:
 291                         f->private_data = &wd_dev.watchdog[WD2_ID];
 292                         break;
 293                 default:
 294                         return(-ENODEV);
 295         }
 296
 297         /* Register IRQ on first open of device */
 298         if(0 == wd_dev.initialized)
 299         {
 300                 if (request_irq(wd_dev.irq,
 301                                                 &wd_interrupt,
 302                                                 IRQF_SHARED,
 303                                                 WD_OBPNAME,
 304                                                 (void *)wd_dev.regs)) {
 305                         printk("%s: Cannot register IRQ %d\n",
 306                                 WD_OBPNAME, wd_dev.irq);
 307                         return(-EBUSY);
 308                 }
 309                 wd_dev.initialized = 1;
 310         }
 311
 312         return(nonseekable_open(inode, f));
 313 }
 314
 315 static int wd_release(struct inode *inode, struct file *file)
 316 {
 317         return 0;
 318 }
 319
 320 static int wd_ioctl(struct inode *inode, struct file *file,
 321                      unsigned int cmd, unsigned long arg)
 322 {
 323         int     setopt                          = 0;
 324         struct  wd_timer* pTimer        = (struct wd_timer*)file->private_data;
 325         void __user *argp = (void __user *)arg;
 326         struct  watchdog_info info      = {
 327                 0,
 328                 0,
 329                 "Altera EPF8820ATC144-4"
 330         };
 331
 332         if(NULL == pTimer) {
 333                 return(-EINVAL);
 334         }
 335
 336         switch(cmd)
 337         {
 338                 /* Generic Linux IOCTLs */
 339                 case WDIOC_GETSUPPORT:
 340                         if(copy_to_user(argp, &info, sizeof(struct watchdog_info))) {
 341                                 return(-EFAULT);
 342                         }
 343                         break;
 344                 case WDIOC_GETSTATUS:
 345                 case WDIOC_GETBOOTSTATUS:
 346                         if (put_user(0, (int __user *)argp))
 347                                 return -EFAULT;
 348                         break;
 349                 case WDIOC_KEEPALIVE:
 350                         wd_pingtimer(pTimer);
 351                         break;
 352                 case WDIOC_SETOPTIONS:
 353                         if(copy_from_user(&setopt, argp, sizeof(unsigned int))) {
 354                                 return -EFAULT;
 355                         }
 356                         if(setopt & WDIOS_DISABLECARD) {
 357                                 if(wd_dev.opt_enable) {
 358                                         printk(
 359                                                 "%s: cannot disable watchdog in ENABLED mode\n",
 360                                                 WD_OBPNAME);
 361                                         return(-EINVAL);
 362                                 }
 363                                 wd_stoptimer(pTimer);
 364                         }
 365                         else if(setopt & WDIOS_ENABLECARD) {
 366                                 wd_starttimer(pTimer);
 367                         }
 368                         else {
 369                                 return(-EINVAL);
 370                         }
 371                         break;
 372                 /* Solaris-compatible IOCTLs */
 373                 case WIOCGSTAT:
 374                         setopt = wd_getstatus(pTimer);
 375                         if(copy_to_user(argp, &setopt, sizeof(unsigned int))) {
 376                                 return(-EFAULT);
 377                         }
 378                         break;
 379                 case WIOCSTART:
 380                         wd_starttimer(pTimer);
 381                         break;
 382                 case WIOCSTOP:
 383                         if(wd_dev.opt_enable) {
 384                                 printk("%s: cannot disable watchdog in ENABLED mode\n",
 385                                         WD_OBPNAME);
 386                                 return(-EINVAL);
 387                         }
 388                         wd_stoptimer(pTimer);
 389                         break;
 390                 default:
 391                         return(-EINVAL);
 392         }
 393         return(0);
 394 }
 395
 396 static long wd_compat_ioctl(struct file *file, unsigned int cmd,
 397                 unsigned long arg)
 398 {
 399         int rval = -ENOIOCTLCMD;
 400
 401         switch (cmd) {
 402         /* solaris ioctls are specific to this driver */
 403         case WIOCSTART:
 404         case WIOCSTOP:
 405         case WIOCGSTAT:
 406                 lock_kernel();
 407                 rval = wd_ioctl(file->f_dentry->d_inode, file, cmd, arg);
 408                 unlock_kernel();
 409                 break;
 410         /* everything else is handled by the generic compat layer */
 411         default:
 412                 break;
 413         }
 414
 415         return rval;
 416 }
 417
 418 static ssize_t wd_write(struct file     *file,
 419                         const char      __user *buf,
 420                         size_t          count,
 421                         loff_t          *ppos)
 422 {
 423         struct wd_timer* pTimer = (struct wd_timer*)file->private_data;
 424
 425         if(NULL == pTimer) {
 426                 return(-EINVAL);
 427         }
 428
 429         if (count) {
 430                 wd_pingtimer(pTimer);
 431                 return 1;
 432         }
 433         return 0;
 434 }
 435
 436 static ssize_t wd_read(struct file * file, char __user *buffer,
 437                         size_t count, loff_t *ppos)
 438 {
 439 #ifdef WD_DEBUG
 440         wd_dumpregs();
 441         return(0);
 442 #else
 443         return(-EINVAL);
 444 #endif /* ifdef WD_DEBUG */
 445 }
 446
 447 static irqreturn_t wd_interrupt(int irq, void *dev_id)
 448 {
 449         /* Only WD0 will interrupt-- others are NMI and we won't
 450          * see them here....
 451          */
 452         spin_lock_irq(&wd_dev.lock);
 453         if((unsigned long)wd_dev.regs == (unsigned long)dev_id)
 454         {
 455                 wd_stoptimer(&wd_dev.watchdog[WD0_ID]);
 456                 wd_dev.watchdog[WD0_ID].runstatus |=  WD_STAT_SVCD;
 457         }
 458         spin_unlock_irq(&wd_dev.lock);
 459         return IRQ_HANDLED;
 460 }
 461
 462 static struct file_operations wd_fops = {
 463         .owner =        THIS_MODULE,
 464         .ioctl =        wd_ioctl,
 465         .compat_ioctl = wd_compat_ioctl,
 466         .open =         wd_open,
 467         .write =        wd_write,
 468         .read =         wd_read,
 469         .release =      wd_release,
 470 };
 471
 472 static struct miscdevice wd0_miscdev = { WD0_MINOR, WD0_DEVNAME, &wd_fops };
 473 static struct miscdevice wd1_miscdev = { WD1_MINOR, WD1_DEVNAME, &wd_fops };
 474 static struct miscdevice wd2_miscdev = { WD2_MINOR, WD2_DEVNAME, &wd_fops };
 475
 476 #ifdef WD_DEBUG
 477 static void wd_dumpregs(void)
 478 {
 479         /* Reading from downcounters initiates watchdog countdown--
 480          * Example is included below for illustration purposes.
 481          */
 482         int i;
 483         printk("%s: dumping register values\n", WD_OBPNAME);
 484         for(i = WD0_ID; i < WD_NUMDEVS; ++i) {
 485                         /* printk("\t%s%i: dcntr  at 0x%lx: 0x%x\n",
 486                          *      WD_OBPNAME,
 487                          *      i,
 488                          *      (unsigned long)(&wd_dev.watchdog[i].regs->dcntr),
 489                          *      readw(&wd_dev.watchdog[i].regs->dcntr));
 490                          */
 491                         printk("\t%s%i: limit  at 0x%lx: 0x%x\n",
 492                                 WD_OBPNAME,
 493                                 i,
 494                                 (unsigned long)(&wd_dev.watchdog[i].regs->limit),
 495                                 readw(&wd_dev.watchdog[i].regs->limit));
 496                         printk("\t%s%i: status at 0x%lx: 0x%x\n",
 497                                 WD_OBPNAME,
 498                                 i,
 499                                 (unsigned long)(&wd_dev.watchdog[i].regs->status),
 500                                 readb(&wd_dev.watchdog[i].regs->status));
 501                         printk("\t%s%i: driver status: 0x%x\n",
 502                                 WD_OBPNAME,
 503                                 i,
 504                                 wd_getstatus(&wd_dev.watchdog[i]));
 505         }
 506         printk("\tintr_mask  at %p: 0x%x\n",
 507                 wd_dev.regs + PLD_IMASK,
 508                 readb(wd_dev.regs + PLD_IMASK));
 509         printk("\tpld_status at %p: 0x%x\n",
 510                 wd_dev.regs + PLD_STATUS,
 511                 readb(wd_dev.regs + PLD_STATUS));
 512 }
 513 #endif
 514
 515 /* Enable or disable watchdog interrupts
 516  * Because of the CP1400 defect this should only be
 517  * called during initialzation or by wd_[start|stop]timer()
 518  *
 519  * pTimer       - pointer to timer device, or NULL to indicate all timers
 520  * enable       - non-zero to enable interrupts, zero to disable
 521  */
 522 static void wd_toggleintr(struct wd_timer* pTimer, int enable)
 523 {
 524         unsigned char curregs = wd_readb(wd_dev.regs + PLD_IMASK);
 525         unsigned char setregs =
 526                 (NULL == pTimer) ?
 527                         (WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) :
 528                         (pTimer->intr_mask);
 529
 530         (WD_INTR_ON == enable) ?
 531                 (curregs &= ~setregs):
 532                 (curregs |=  setregs);
 533
 534         wd_writeb(curregs, wd_dev.regs + PLD_IMASK);
 535         return;
 536 }
 537
 538 /* Reset countdown timer with 'limit' value and continue countdown.
 539  * This will not start a stopped timer.
 540  *
 541  * pTimer       - pointer to timer device
 542  */
 543 static void wd_pingtimer(struct wd_timer* pTimer)
 544 {
 545         if (wd_readb(pTimer->regs + WD_STATUS) & WD_S_RUNNING) {
 546                 wd_readw(pTimer->regs + WD_DCNTR);
 547         }
 548 }
 549
 550 /* Stop a running watchdog timer-- the timer actually keeps
 551  * running, but the interrupt is masked so that no action is
 552  * taken upon expiration.
 553  *
 554  * pTimer       - pointer to timer device
 555  */
 556 static void wd_stoptimer(struct wd_timer* pTimer)
 557 {
 558         if(wd_readb(pTimer->regs + WD_STATUS) & WD_S_RUNNING) {
 559                 wd_toggleintr(pTimer, WD_INTR_OFF);
 560
 561                 if(wd_dev.isbaddoggie) {
 562                         pTimer->runstatus |= WD_STAT_BSTOP;
 563                         wd_brokentimer((unsigned long)&wd_dev);
 564                 }
 565         }
 566 }
 567
 568 /* Start a watchdog timer with the specified limit value
 569  * If the watchdog is running, it will be restarted with
 570  * the provided limit value.
 571  *
 572  * This function will enable interrupts on the specified
 573  * watchdog.
 574  *
 575  * pTimer       - pointer to timer device
 576  * limit        - limit (countdown) value in 1/10th seconds
 577  */
 578 static void wd_starttimer(struct wd_timer* pTimer)
 579 {
 580         if(wd_dev.isbaddoggie) {
 581                 pTimer->runstatus &= ~WD_STAT_BSTOP;
 582         }
 583         pTimer->runstatus &= ~WD_STAT_SVCD;
 584
 585         wd_writew(pTimer->timeout, pTimer->regs + WD_LIMIT);
 586         wd_toggleintr(pTimer, WD_INTR_ON);
 587 }
 588
 589 /* Restarts timer with maximum limit value and
 590  * does not unset 'brokenstop' value.
 591  */
 592 static void wd_resetbrokentimer(struct wd_timer* pTimer)
 593 {
 594         wd_toggleintr(pTimer, WD_INTR_ON);
 595         wd_writew(WD_BLIMIT, pTimer->regs + WD_LIMIT);
 596 }
 597
 598 /* Timer device initialization helper.
 599  * Returns 0 on success, other on failure
 600  */
 601 static int wd_inittimer(int whichdog)
 602 {
 603         struct miscdevice                               *whichmisc;
 604         void __iomem *whichregs;
 605         char                                                    whichident[8];
 606         int                                                             whichmask;
 607         __u16                                                   whichlimit;
 608
 609         switch(whichdog)
 610         {
 611                 case WD0_ID:
 612                         whichmisc = &wd0_miscdev;
 613                         strcpy(whichident, "RIC");
 614                         whichregs = wd_dev.regs + WD0_OFF;
 615                         whichmask = WD0_INTR_MASK;
 616                         whichlimit= (0 == wd0_timeout)  ?
 617                                                 (wd_dev.opt_timeout):
 618                                                 (wd0_timeout);
 619                         break;
 620                 case WD1_ID:
 621                         whichmisc = &wd1_miscdev;
 622                         strcpy(whichident, "XIR");
 623                         whichregs = wd_dev.regs + WD1_OFF;
 624                         whichmask = WD1_INTR_MASK;
 625                         whichlimit= (0 == wd1_timeout)  ?
 626                                                 (wd_dev.opt_timeout):
 627                                                 (wd1_timeout);
 628                         break;
 629                 case WD2_ID:
 630                         whichmisc = &wd2_miscdev;
 631                         strcpy(whichident, "POR");
 632                         whichregs = wd_dev.regs + WD2_OFF;
 633                         whichmask = WD2_INTR_MASK;
 634                         whichlimit= (0 == wd2_timeout)  ?
 635                                                 (wd_dev.opt_timeout):
 636                                                 (wd2_timeout);
 637                         break;
 638                 default:
 639                         printk("%s: %s: invalid watchdog id: %i\n",
 640                                 WD_OBPNAME, __FUNCTION__, whichdog);
 641                         return(1);
 642         }
 643         if(0 != misc_register(whichmisc))
 644         {
 645                 return(1);
 646         }
 647         wd_dev.watchdog[whichdog].regs                  = whichregs;
 648         wd_dev.watchdog[whichdog].timeout               = whichlimit;
 649         wd_dev.watchdog[whichdog].intr_mask             = whichmask;
 650         wd_dev.watchdog[whichdog].runstatus     &= ~WD_STAT_BSTOP;
 651         wd_dev.watchdog[whichdog].runstatus     |= WD_STAT_INIT;
 652
 653         printk("%s%i: %s hardware watchdog [%01i.%i sec] %s\n",
 654                 WD_OBPNAME,
 655                 whichdog,
 656                 whichident,
 657                 wd_dev.watchdog[whichdog].timeout / 10,
 658                 wd_dev.watchdog[whichdog].timeout % 10,
 659                 (0 != wd_dev.opt_enable) ? "in ENABLED mode" : "");
 660         return(0);
 661 }
 662
 663 /* Timer method called to reset stopped watchdogs--
 664  * because of the PLD bug on CP1400, we cannot mask
 665  * interrupts within the PLD so me must continually
 666  * reset the timers ad infinitum.
 667  */
 668 static void wd_brokentimer(unsigned long data)
 669 {
 670         struct wd_device* pDev = (struct wd_device*)data;
 671         int id, tripped = 0;
 672
 673         /* kill a running timer instance, in case we
 674          * were called directly instead of by kernel timer
 675          */
 676         if(timer_pending(&wd_timer)) {
 677                 del_timer(&wd_timer);
 678         }
 679
 680         for(id = WD0_ID; id < WD_NUMDEVS; ++id) {
 681                 if(pDev->watchdog[id].runstatus & WD_STAT_BSTOP) {
 682                         ++tripped;
 683                         wd_resetbrokentimer(&pDev->watchdog[id]);
 684                 }
 685         }
 686
 687         if(tripped) {
 688                 /* there is at least one timer brokenstopped-- reschedule */
 689                 init_timer(&wd_timer);
 690                 wd_timer.expires = WD_BTIMEOUT;
 691                 add_timer(&wd_timer);
 692         }
 693 }
 694
 695 static int wd_getstatus(struct wd_timer* pTimer)
 696 {
 697         unsigned char stat = wd_readb(pTimer->regs + WD_STATUS);
 698         unsigned char intr = wd_readb(wd_dev.regs + PLD_IMASK);
 699         unsigned char ret  = WD_STOPPED;
 700
 701         /* determine STOPPED */
 702         if(0 == stat ) {
 703                 return(ret);
 704         }
 705         /* determine EXPIRED vs FREERUN vs RUNNING */
 706         else if(WD_S_EXPIRED & stat) {
 707                 ret = WD_EXPIRED;
 708         }
 709         else if(WD_S_RUNNING & stat) {
 710                 if(intr & pTimer->intr_mask) {
 711                         ret = WD_FREERUN;
 712                 }
 713                 else {
 714                         /* Fudge WD_EXPIRED status for defective CP1400--
 715                          * IF timer is running
 716                          *      AND brokenstop is set
 717                          *      AND an interrupt has been serviced
 718                          * we are WD_EXPIRED.
 719                          *
 720                          * IF timer is running
 721                          *      AND brokenstop is set
 722                          *      AND no interrupt has been serviced
 723                          * we are WD_FREERUN.
 724                          */
 725                         if(wd_dev.isbaddoggie && (pTimer->runstatus & WD_STAT_BSTOP)) {
 726                                 if(pTimer->runstatus & WD_STAT_SVCD) {
 727                                         ret = WD_EXPIRED;
 728                                 }
 729                                 else {
 730                                         /* we could as well pretend we are expired */
 731                                         ret = WD_FREERUN;
 732                                 }
 733                         }
 734                         else {
 735                                 ret = WD_RUNNING;
 736                         }
 737                 }
 738         }
 739
 740         /* determine SERVICED */
 741         if(pTimer->runstatus & WD_STAT_SVCD) {
 742                 ret |= WD_SERVICED;
 743         }
 744
 745         return(ret);
 746 }
 747
 748 static int __init wd_init(void)
 749 {
 750         int     id;
 751         struct  linux_ebus *ebus = NULL;
 752         struct  linux_ebus_device *edev = NULL;
 753
 754         for_each_ebus(ebus) {
 755                 for_each_ebusdev(edev, ebus) {
 756                         if (!strcmp(edev->ofdev.node->name, WD_OBPNAME))
 757                                 goto ebus_done;
 758                 }
 759         }
 760
 761 ebus_done:
 762         if(!edev) {
 763                 printk("%s: unable to locate device\n", WD_OBPNAME);
 764                 return -ENODEV;
 765         }
 766
 767         wd_dev.regs =
 768                 ioremap(edev->resource[0].start, 4 * WD_TIMER_REGSZ); /* ? */
 769
 770         if(NULL == wd_dev.regs) {
 771                 printk("%s: unable to map registers\n", WD_OBPNAME);
 772                 return(-ENODEV);
 773         }
 774
 775         /* initialize device structure from OBP parameters */
 776         wd_dev.irq                      = edev->irqs[0];
 777         wd_dev.opt_enable       = wd_opt_enable();
 778         wd_dev.opt_reboot       = wd_opt_reboot();
 779         wd_dev.opt_timeout      = wd_opt_timeout();
 780         wd_dev.isbaddoggie      = wd_isbroken();
 781
 782         /* disable all interrupts unless watchdog-enabled? == true */
 783         if(! wd_dev.opt_enable) {
 784                 wd_toggleintr(NULL, WD_INTR_OFF);
 785         }
 786
 787         /* register miscellaneous devices */
 788         for(id = WD0_ID; id < WD_NUMDEVS; ++id) {
 789                 if(0 != wd_inittimer(id)) {
 790                         printk("%s%i: unable to initialize\n", WD_OBPNAME, id);
 791                 }
 792         }
 793
 794         /* warn about possible defective PLD */
 795         if(wd_dev.isbaddoggie) {
 796                 init_timer(&wd_timer);
 797                 wd_timer.function       = wd_brokentimer;
 798                 wd_timer.data           = (unsigned long)&wd_dev;
 799                 wd_timer.expires        = WD_BTIMEOUT;
 800
 801                 printk("%s: PLD defect workaround enabled for model %s\n",
 802                         WD_OBPNAME, WD_BADMODEL);
 803         }
 804         return(0);
 805 }
 806
 807 static void __exit wd_cleanup(void)
 808 {
 809         int id;
 810
 811         /* if 'watchdog-enable?' == TRUE, timers are not stopped
 812          * when module is unloaded.  All brokenstopped timers will
 813          * also now eventually trip.
 814          */
 815         for(id = WD0_ID; id < WD_NUMDEVS; ++id) {
 816                 if(WD_S_RUNNING == wd_readb(wd_dev.watchdog[id].regs + WD_STATUS)) {
 817                         if(wd_dev.opt_enable) {
 818                                 printk(KERN_WARNING "%s%i: timer not stopped at release\n",
 819                                         WD_OBPNAME, id);
 820                         }
 821                         else {
 822                                 wd_stoptimer(&wd_dev.watchdog[id]);
 823                                 if(wd_dev.watchdog[id].runstatus & WD_STAT_BSTOP) {
 824                                         wd_resetbrokentimer(&wd_dev.watchdog[id]);
 825                                         printk(KERN_WARNING
 826                                                         "%s%i: defect workaround disabled at release, "\
 827                                                         "timer expires in ~%01i sec\n",
 828                                                         WD_OBPNAME, id,
 829                                                         wd_readw(wd_dev.watchdog[id].regs + WD_LIMIT) / 10);
 830                                 }
 831                         }
 832                 }
 833         }
 834
 835         if(wd_dev.isbaddoggie && timer_pending(&wd_timer)) {
 836                 del_timer(&wd_timer);
 837         }
 838         if(0 != (wd_dev.watchdog[WD0_ID].runstatus & WD_STAT_INIT)) {
 839                 misc_deregister(&wd0_miscdev);
 840         }
 841         if(0 != (wd_dev.watchdog[WD1_ID].runstatus & WD_STAT_INIT)) {
 842                 misc_deregister(&wd1_miscdev);
 843         }
 844         if(0 != (wd_dev.watchdog[WD2_ID].runstatus & WD_STAT_INIT)) {
 845                 misc_deregister(&wd2_miscdev);
 846         }
 847         if(0 != wd_dev.initialized) {
 848                 free_irq(wd_dev.irq, (void *)wd_dev.regs);
 849         }
 850         iounmap(wd_dev.regs);
 851 }
 852
 853 module_init(wd_init);
 854 module_exit(wd_cleanup);