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  * TODO:        DevFS support (/dev/watchdogs/0 ... /dev/watchdogs/2)
  14  *
  15  * Copyright (c) 2000 Eric Brower (ebrower@usa.net)
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/fs.h>
  21 #include <linux/errno.h>
  22 #include <linux/major.h>
  23 #include <linux/init.h>
  24 #include <linux/miscdevice.h>
  25 #include <linux/sched.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/ioport.h>
  28 #include <linux/timer.h>
  29 #include <asm/irq.h>
  30 #include <asm/ebus.h>
  31 #include <asm/oplib.h>
  32 #include <asm/uaccess.h>
  33
  34 #include <asm/watchdog.h>
  35
  36 #define WD_OBPNAME      "watchdog"
  37 #define WD_BADMODEL "SUNW,501-5336"
  38 #define WD_BTIMEOUT     (jiffies + (HZ * 1000))
  39 #define WD_BLIMIT       0xFFFF
  40
  41 #define WD0_DEVNAME "watchdog0"
  42 #define WD1_DEVNAME "watchdog1"
  43 #define WD2_DEVNAME "watchdog2"
  44
  45 #define WD0_MINOR       212
  46 #define WD1_MINOR       213
  47 #define WD2_MINOR       214
  48
  49
  50 /* Internal driver definitions
  51  */
  52 #define WD0_ID                  0               /* Watchdog0                                            */
  53 #define WD1_ID                  1               /* Watchdog1                                            */
  54 #define WD2_ID                  2               /* Watchdog2                                            */
  55 #define WD_NUMDEVS              3               /* Device contains 3 timers                     */
  56
  57 #define WD_INTR_OFF             0               /* Interrupt disable value                      */
  58 #define WD_INTR_ON              1               /* Interrupt enable value                       */
  59
  60 #define WD_STAT_INIT    0x01    /* Watchdog timer is initialized        */
  61 #define WD_STAT_BSTOP   0x02    /* Watchdog timer is brokenstopped      */
  62 #define WD_STAT_SVCD    0x04    /* Watchdog interrupt occurred          */
  63
  64 /* Register value definitions
  65  */
  66 #define WD0_INTR_MASK   0x01    /* Watchdog device interrupt masks      */
  67 #define WD1_INTR_MASK   0x02
  68 #define WD2_INTR_MASK   0x04
  69
  70 #define WD_S_RUNNING    0x01    /* Watchdog device status running       */
  71 #define WD_S_EXPIRED    0x02    /* Watchdog device status expired       */
  72
  73 /* Sun uses Altera PLD EPF8820ATC144-4
  74  * providing three hardware watchdogs:
  75  *
  76  *      1) RIC - sends an interrupt when triggered
  77  *      2) XIR - asserts XIR_B_RESET when triggered, resets CPU
  78  *      3) POR - asserts POR_B_RESET when triggered, resets CPU, backplane, board
  79  *
  80  *** Timer register block definition (struct wd_timer_regblk)
  81  *
  82  * dcntr and limit registers (halfword access):
  83  * -------------------
  84  * | 15 | ...| 1 | 0 |
  85  * -------------------
  86  * |-  counter val  -|
  87  * -------------------
  88  * dcntr -      Current 16-bit downcounter value.
  89  *                      When downcounter reaches '0' watchdog expires.
  90  *                      Reading this register resets downcounter with 'limit' value.
  91  * limit -      16-bit countdown value in 1/10th second increments.
  92  *                      Writing this register begins countdown with input value.
  93  *                      Reading from this register does not affect counter.
  94  * NOTES:       After watchdog reset, dcntr and limit contain '1'
  95  *
  96  * status register (byte access):
  97  * ---------------------------
  98  * | 7 | ... | 2 |  1  |  0  |
  99  * --------------+------------
 100  * |-   UNUSED  -| EXP | RUN |
 101  * ---------------------------
 102  * status-      Bit 0 - Watchdog is running
 103  *                      Bit 1 - Watchdog has expired
 104  *
 105  *** PLD register block definition (struct wd_pld_regblk)
 106  *
 107  * intr_mask register (byte access):
 108  * ---------------------------------
 109  * | 7 | ... | 3 |  2  |  1  |  0  |
 110  * +-------------+------------------
 111  * |-   UNUSED  -| WD3 | WD2 | WD1 |
 112  * ---------------------------------
 113  * WD3 -  1 == Interrupt disabled for watchdog 3
 114  * WD2 -  1 == Interrupt disabled for watchdog 2
 115  * WD1 -  1 == Interrupt disabled for watchdog 1
 116  *
 117  * pld_status register (byte access):
 118  * UNKNOWN, MAGICAL MYSTERY REGISTER
 119  *
 120  */
 121 struct wd_timer_regblk {
 122         volatile __u16  dcntr;          /* down counter         - hw    */
 123         volatile __u16  dcntr_pad;
 124         volatile __u16  limit;          /* limit register       - hw    */
 125         volatile __u16  limit_pad;
 126         volatile __u8   status;         /* status register      - b             */
 127         volatile __u8   status_pad;
 128         volatile __u16  status_pad2;
 129         volatile __u32  pad32;          /* yet more padding                     */
 130 };
 131
 132 struct wd_pld_regblk {
 133         volatile __u8   intr_mask;      /* interrupt mask       - b             */
 134         volatile __u8   intr_mask_pad;
 135         volatile __u16  intr_mask_pad2;
 136         volatile __u8   status;         /* device status        - b             */
 137         volatile __u8   status_pad;
 138         volatile __u16  status_pad2;
 139 };
 140
 141 struct wd_regblk {
 142         volatile struct wd_timer_regblk         wd0_regs;
 143         volatile struct wd_timer_regblk         wd1_regs;
 144         volatile struct wd_timer_regblk         wd2_regs;
 145         volatile struct wd_pld_regblk           pld_regs;
 146 };
 147
 148 /* Individual timer structure
 149  */
 150 struct wd_timer {
 151         __u16                   timeout;
 152         __u8                    intr_mask;
 153         unsigned char   runstatus;
 154         volatile struct wd_timer_regblk* regs;
 155 };
 156
 157 /* Device structure
 158  */
 159 struct wd_device {
 160         int                             irq;
 161         spinlock_t              lock;
 162         unsigned char   isbaddoggie;    /* defective PLD */
 163         unsigned char   opt_enable;
 164         unsigned char   opt_reboot;
 165         unsigned short  opt_timeout;
 166         unsigned char   initialized;
 167         struct wd_timer watchdog[WD_NUMDEVS];
 168         volatile struct wd_regblk* regs;
 169 };
 170
 171 static struct wd_device wd_dev = {
 172                 0, SPIN_LOCK_UNLOCKED, 0, 0, 0, 0,
 173 };
 174
 175 static struct timer_list wd_timer;
 176
 177 static int wd0_timeout = 0;
 178 static int wd1_timeout = 0;
 179 static int wd2_timeout = 0;
 180
 181 #ifdef MODULE
 182 MODULE_PARM             (wd0_timeout, "i");
 183 MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs");
 184 MODULE_PARM     (wd1_timeout, "i");
 185 MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs");
 186 MODULE_PARM     (wd2_timeout, "i");
 187 MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs");
 188
 189 MODULE_AUTHOR
 190         ("Eric Brower <ebrower@usa.net>");
 191 MODULE_DESCRIPTION
 192         ("Hardware watchdog driver for Sun Microsystems CP1400/1500");
 193 MODULE_LICENSE("GPL");
 194 MODULE_SUPPORTED_DEVICE
 195         ("watchdog");
 196 #endif /* ifdef MODULE */
 197
 198 /* Forward declarations of internal methods
 199  */
 200 #ifdef WD_DEBUG
 201 static void wd_dumpregs(void);
 202 #endif
 203 static irqreturn_t wd_interrupt(int irq, void *dev_id, struct pt_regs *regs);
 204 static void wd_toggleintr(struct wd_timer* pTimer, int enable);
 205 static void wd_pingtimer(struct wd_timer* pTimer);
 206 static void wd_starttimer(struct wd_timer* pTimer);
 207 static void wd_resetbrokentimer(struct wd_timer* pTimer);
 208 static void wd_stoptimer(struct wd_timer* pTimer);
 209 static void wd_brokentimer(unsigned long data);
 210 static int  wd_getstatus(struct wd_timer* pTimer);
 211
 212 /* PLD expects words to be written in LSB format,
 213  * so we must flip all words prior to writing them to regs
 214  */
 215 static inline unsigned short flip_word(unsigned short word)
 216 {
 217         return ((word & 0xff) << 8) | ((word >> 8) & 0xff);
 218 }
 219
 220 #define wd_writew(val, addr)    (writew(flip_word(val), addr))
 221 #define wd_readw(addr)                  (flip_word(readw(addr)))
 222 #define wd_writeb(val, addr)    (writeb(val, addr))
 223 #define wd_readb(addr)                  (readb(addr))
 224
 225
 226 /* CP1400s seem to have broken PLD implementations--
 227  * the interrupt_mask register cannot be written, so
 228  * no timer interrupts can be masked within the PLD.
 229  */
 230 static inline int wd_isbroken(void)
 231 {
 232         /* we could test this by read/write/read/restore
 233          * on the interrupt mask register only if OBP
 234          * 'watchdog-enable?' == FALSE, but it seems
 235          * ubiquitous on CP1400s
 236          */
 237         char val[32];
 238         prom_getproperty(prom_root_node, "model", val, sizeof(val));
 239         return((!strcmp(val, WD_BADMODEL)) ? 1 : 0);
 240 }
 241
 242 /* Retrieve watchdog-enable? option from OBP
 243  * Returns 0 if false, 1 if true
 244  */
 245 static inline int wd_opt_enable(void)
 246 {
 247         int opt_node;
 248
 249         opt_node = prom_getchild(prom_root_node);
 250         opt_node = prom_searchsiblings(opt_node, "options");
 251         return((-1 == prom_getint(opt_node, "watchdog-enable?")) ? 0 : 1);
 252 }
 253
 254 /* Retrieve watchdog-reboot? option from OBP
 255  * Returns 0 if false, 1 if true
 256  */
 257 static inline int wd_opt_reboot(void)
 258 {
 259         int opt_node;
 260
 261         opt_node = prom_getchild(prom_root_node);
 262         opt_node = prom_searchsiblings(opt_node, "options");
 263         return((-1 == prom_getint(opt_node, "watchdog-reboot?")) ? 0 : 1);
 264 }
 265
 266 /* Retrieve watchdog-timeout option from OBP
 267  * Returns OBP value, or 0 if not located
 268  */
 269 static inline int wd_opt_timeout(void)
 270 {
 271         int opt_node;
 272         char value[32];
 273         char *p = value;
 274
 275         opt_node = prom_getchild(prom_root_node);
 276         opt_node = prom_searchsiblings(opt_node, "options");
 277         opt_node = prom_getproperty(opt_node,
 278                                                                 "watchdog-timeout",
 279                                                                 value,
 280                                                                 sizeof(value));
 281         if(-1 != opt_node) {
 282                 /* atoi implementation */
 283                 for(opt_node = 0; /* nop */; p++) {
 284                         if(*p >= '0' && *p <= '9') {
 285                                 opt_node = (10*opt_node)+(*p-'0');
 286                         }
 287                         else {
 288                                 break;
 289                         }
 290                 }
 291         }
 292         return((-1 == opt_node) ? (0) : (opt_node));
 293 }
 294
 295 static int wd_open(struct inode *inode, struct file *f)
 296 {
 297         switch(iminor(inode))
 298         {
 299                 case WD0_MINOR:
 300                         f->private_data = &wd_dev.watchdog[WD0_ID];
 301                         break;
 302                 case WD1_MINOR:
 303                         f->private_data = &wd_dev.watchdog[WD1_ID];
 304                         break;
 305                 case WD2_MINOR:
 306                         f->private_data = &wd_dev.watchdog[WD2_ID];
 307                         break;
 308                 default:
 309                         return(-ENODEV);
 310         }
 311
 312         /* Register IRQ on first open of device */
 313         if(0 == wd_dev.initialized)
 314         {
 315                 if (request_irq(wd_dev.irq,
 316                                                 &wd_interrupt,
 317                                                 SA_SHIRQ,
 318                                                 WD_OBPNAME,
 319                                                 (void *)wd_dev.regs)) {
 320                         printk("%s: Cannot register IRQ %s\n",
 321                                 WD_OBPNAME, __irq_itoa(wd_dev.irq));
 322                         return(-EBUSY);
 323                 }
 324                 wd_dev.initialized = 1;
 325         }
 326
 327         return(0);
 328 }
 329
 330 static int wd_release(struct inode *inode, struct file *file)
 331 {
 332         return 0;
 333 }
 334
 335 static int wd_ioctl(struct inode *inode, struct file *file,
 336                      unsigned int cmd, unsigned long arg)
 337 {
 338         int     setopt                          = 0;
 339         struct  wd_timer* pTimer        = (struct wd_timer*)file->private_data;
 340         struct  watchdog_info info      = {
 341                 0,
 342                 0,
 343                 "Altera EPF8820ATC144-4"
 344         };
 345
 346         if(NULL == pTimer) {
 347                 return(-EINVAL);
 348         }
 349
 350         switch(cmd)
 351         {
 352                 /* Generic Linux IOCTLs */
 353                 case WDIOC_GETSUPPORT:
 354                         if(copy_to_user((struct watchdog_info *)arg,
 355                                                         (struct watchdog_info *)&info,
 356                                                         sizeof(struct watchdog_info))) {
 357                                 return(-EFAULT);
 358                         }
 359                         break;
 360                 case WDIOC_GETSTATUS:
 361                 case WDIOC_GETBOOTSTATUS:
 362                         if (put_user(0, (int *) arg))
 363                                 return -EFAULT;
 364                         break;
 365                 case WDIOC_KEEPALIVE:
 366                         wd_pingtimer(pTimer);
 367                         break;
 368                 case WDIOC_SETOPTIONS:
 369                         if(copy_from_user(&setopt, (void*) arg, sizeof(unsigned int))) {
 370                                 return -EFAULT;
 371                         }
 372                         if(setopt & WDIOS_DISABLECARD) {
 373                                 if(wd_dev.opt_enable) {
 374                                         printk(
 375                                                 "%s: cannot disable watchdog in ENABLED mode\n",
 376                                                 WD_OBPNAME);
 377                                         return(-EINVAL);
 378                                 }
 379                                 wd_stoptimer(pTimer);
 380                         }
 381                         else if(setopt & WDIOS_ENABLECARD) {
 382                                 wd_starttimer(pTimer);
 383                         }
 384                         else {
 385                                 return(-EINVAL);
 386                         }
 387                         break;
 388                 /* Solaris-compatible IOCTLs */
 389                 case WIOCGSTAT:
 390                         setopt = wd_getstatus(pTimer);
 391                         if(copy_to_user((void*)arg, &setopt, sizeof(unsigned int))) {
 392                                 return(-EFAULT);
 393                         }
 394                         break;
 395                 case WIOCSTART:
 396                         wd_starttimer(pTimer);
 397                         break;
 398                 case WIOCSTOP:
 399                         if(wd_dev.opt_enable) {
 400                                 printk("%s: cannot disable watchdog in ENABLED mode\n",
 401                                         WD_OBPNAME);
 402                                 return(-EINVAL);
 403                         }
 404                         wd_stoptimer(pTimer);
 405                         break;
 406                 default:
 407                         return(-EINVAL);
 408         }
 409         return(0);
 410 }
 411
 412 static ssize_t wd_write(        struct file     *file,
 413                                                         const char              *buf,
 414                                                         size_t                  count,
 415                                                         loff_t                  *ppos)
 416 {
 417         struct wd_timer* pTimer = (struct wd_timer*)file->private_data;
 418
 419         if(NULL == pTimer) {
 420                 return(-EINVAL);
 421         }
 422
 423         if (ppos != &file->f_pos)
 424                 return -ESPIPE;
 425
 426         if (count) {
 427                 wd_pingtimer(pTimer);
 428                 return 1;
 429         }
 430         return 0;
 431 }
 432
 433 static ssize_t wd_read(struct file * file, char * buffer,
 434                         size_t count, loff_t *ppos)
 435 {
 436 #ifdef WD_DEBUG
 437         wd_dumpregs();
 438         return(0);
 439 #else
 440         return(-EINVAL);
 441 #endif /* ifdef WD_DEBUG */
 442 }
 443
 444 static irqreturn_t wd_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 445 {
 446         /* Only WD0 will interrupt-- others are NMI and we won't
 447          * see them here....
 448          */
 449         spin_lock_irq(&wd_dev.lock);
 450         if((unsigned long)wd_dev.regs == (unsigned long)dev_id)
 451         {
 452                 wd_stoptimer(&wd_dev.watchdog[WD0_ID]);
 453                 wd_dev.watchdog[WD0_ID].runstatus |=  WD_STAT_SVCD;
 454         }
 455         spin_unlock_irq(&wd_dev.lock);
 456         return IRQ_HANDLED;
 457 }
 458
 459 static struct file_operations wd_fops = {
 460         .owner =        THIS_MODULE,
 461         .ioctl =        wd_ioctl,
 462         .open =         wd_open,
 463         .write =        wd_write,
 464         .read =         wd_read,
 465         .release =      wd_release,
 466 };
 467
 468 static struct miscdevice wd0_miscdev = { WD0_MINOR, WD0_DEVNAME, &wd_fops };
 469 static struct miscdevice wd1_miscdev = { WD1_MINOR, WD1_DEVNAME, &wd_fops };
 470 static struct miscdevice wd2_miscdev = { WD2_MINOR, WD2_DEVNAME, &wd_fops };
 471
 472 #ifdef WD_DEBUG
 473 static void wd_dumpregs(void)
 474 {
 475         /* Reading from downcounters initiates watchdog countdown--
 476          * Example is included below for illustration purposes.
 477          */
 478         int i;
 479         printk("%s: dumping register values\n", WD_OBPNAME);
 480         for(i = WD0_ID; i < WD_NUMDEVS; ++i) {
 481                         /* printk("\t%s%i: dcntr  at 0x%lx: 0x%x\n",
 482                          *      WD_OBPNAME,
 483                          *      i,
 484                          *      (unsigned long)(&wd_dev.watchdog[i].regs->dcntr),
 485                          *      readw(&wd_dev.watchdog[i].regs->dcntr));
 486                          */
 487                         printk("\t%s%i: limit  at 0x%lx: 0x%x\n",
 488                                 WD_OBPNAME,
 489                                 i,
 490                                 (unsigned long)(&wd_dev.watchdog[i].regs->limit),
 491                                 readw(&wd_dev.watchdog[i].regs->limit));
 492                         printk("\t%s%i: status at 0x%lx: 0x%x\n",
 493                                 WD_OBPNAME,
 494                                 i,
 495                                 (unsigned long)(&wd_dev.watchdog[i].regs->status),
 496                                 readb(&wd_dev.watchdog[i].regs->status));
 497                         printk("\t%s%i: driver status: 0x%x\n",
 498                                 WD_OBPNAME,
 499                                 i,
 500                                 wd_getstatus(&wd_dev.watchdog[i]));
 501         }
 502         printk("\tintr_mask  at 0x%lx: 0x%x\n",
 503                 (unsigned long)(&wd_dev.regs->pld_regs.intr_mask),
 504                 readb(&wd_dev.regs->pld_regs.intr_mask));
 505         printk("\tpld_status at 0x%lx: 0x%x\n",
 506                 (unsigned long)(&wd_dev.regs->pld_regs.status),
 507                 readb(&wd_dev.regs->pld_regs.status));
 508 }
 509 #endif
 510
 511 /* Enable or disable watchdog interrupts
 512  * Because of the CP1400 defect this should only be
 513  * called during initialzation or by wd_[start|stop]timer()
 514  *
 515  * pTimer       - pointer to timer device, or NULL to indicate all timers
 516  * enable       - non-zero to enable interrupts, zero to disable
 517  */
 518 static void wd_toggleintr(struct wd_timer* pTimer, int enable)
 519 {
 520         unsigned char curregs = wd_readb(&wd_dev.regs->pld_regs.intr_mask);
 521         unsigned char setregs =
 522                 (NULL == pTimer) ?
 523                         (WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) :
 524                         (pTimer->intr_mask);
 525
 526         (WD_INTR_ON == enable) ?
 527                 (curregs &= ~setregs):
 528                 (curregs |=  setregs);
 529
 530         wd_writeb(curregs, &wd_dev.regs->pld_regs.intr_mask);
 531         return;
 532 }
 533
 534 /* Reset countdown timer with 'limit' value and continue countdown.
 535  * This will not start a stopped timer.
 536  *
 537  * pTimer       - pointer to timer device
 538  */
 539 static void wd_pingtimer(struct wd_timer* pTimer)
 540 {
 541         if(wd_readb(&pTimer->regs->status) & WD_S_RUNNING) {
 542                 wd_readw(&pTimer->regs->dcntr);
 543         }
 544 }
 545
 546 /* Stop a running watchdog timer-- the timer actually keeps
 547  * running, but the interrupt is masked so that no action is
 548  * taken upon expiration.
 549  *
 550  * pTimer       - pointer to timer device
 551  */
 552 static void wd_stoptimer(struct wd_timer* pTimer)
 553 {
 554         if(wd_readb(&pTimer->regs->status) & WD_S_RUNNING) {
 555                 wd_toggleintr(pTimer, WD_INTR_OFF);
 556
 557                 if(wd_dev.isbaddoggie) {
 558                         pTimer->runstatus |= WD_STAT_BSTOP;
 559                         wd_brokentimer((unsigned long)&wd_dev);
 560                 }
 561         }
 562 }
 563
 564 /* Start a watchdog timer with the specified limit value
 565  * If the watchdog is running, it will be restarted with
 566  * the provided limit value.
 567  *
 568  * This function will enable interrupts on the specified
 569  * watchdog.
 570  *
 571  * pTimer       - pointer to timer device
 572  * limit        - limit (countdown) value in 1/10th seconds
 573  */
 574 static void wd_starttimer(struct wd_timer* pTimer)
 575 {
 576         if(wd_dev.isbaddoggie) {
 577                 pTimer->runstatus &= ~WD_STAT_BSTOP;
 578         }
 579         pTimer->runstatus &= ~WD_STAT_SVCD;
 580
 581         wd_writew(pTimer->timeout, &pTimer->regs->limit);
 582         wd_toggleintr(pTimer, WD_INTR_ON);
 583 }
 584
 585 /* Restarts timer with maximum limit value and
 586  * does not unset 'brokenstop' value.
 587  */
 588 static void wd_resetbrokentimer(struct wd_timer* pTimer)
 589 {
 590         wd_toggleintr(pTimer, WD_INTR_ON);
 591         wd_writew(WD_BLIMIT, &pTimer->regs->limit);
 592 }
 593
 594 /* Timer device initialization helper.
 595  * Returns 0 on success, other on failure
 596  */
 597 static int wd_inittimer(int whichdog)
 598 {
 599         struct miscdevice                               *whichmisc;
 600         volatile struct wd_timer_regblk *whichregs;
 601         char                                                    whichident[8];
 602         int                                                             whichmask;
 603         __u16                                                   whichlimit;
 604
 605         switch(whichdog)
 606         {
 607                 case WD0_ID:
 608                         whichmisc = &wd0_miscdev;
 609                         strcpy(whichident, "RIC");
 610                         whichregs = &wd_dev.regs->wd0_regs;
 611                         whichmask = WD0_INTR_MASK;
 612                         whichlimit= (0 == wd0_timeout)  ?
 613                                                 (wd_dev.opt_timeout):
 614                                                 (wd0_timeout);
 615                         break;
 616                 case WD1_ID:
 617                         whichmisc = &wd1_miscdev;
 618                         strcpy(whichident, "XIR");
 619                         whichregs = &wd_dev.regs->wd1_regs;
 620                         whichmask = WD1_INTR_MASK;
 621                         whichlimit= (0 == wd1_timeout)  ?
 622                                                 (wd_dev.opt_timeout):
 623                                                 (wd1_timeout);
 624                         break;
 625                 case WD2_ID:
 626                         whichmisc = &wd2_miscdev;
 627                         strcpy(whichident, "POR");
 628                         whichregs = &wd_dev.regs->wd2_regs;
 629                         whichmask = WD2_INTR_MASK;
 630                         whichlimit= (0 == wd2_timeout)  ?
 631                                                 (wd_dev.opt_timeout):
 632                                                 (wd2_timeout);
 633                         break;
 634                 default:
 635                         printk("%s: %s: invalid watchdog id: %i\n",
 636                                 WD_OBPNAME, __FUNCTION__, whichdog);
 637                         return(1);
 638         }
 639         if(0 != misc_register(whichmisc))
 640         {
 641                 return(1);
 642         }
 643         wd_dev.watchdog[whichdog].regs                  = whichregs;
 644         wd_dev.watchdog[whichdog].timeout               = whichlimit;
 645         wd_dev.watchdog[whichdog].intr_mask             = whichmask;
 646         wd_dev.watchdog[whichdog].runstatus     &= ~WD_STAT_BSTOP;
 647         wd_dev.watchdog[whichdog].runstatus     |= WD_STAT_INIT;
 648
 649         printk("%s%i: %s hardware watchdog [%01i.%i sec] %s\n",
 650                 WD_OBPNAME,
 651                 whichdog,
 652                 whichident,
 653                 wd_dev.watchdog[whichdog].timeout / 10,
 654                 wd_dev.watchdog[whichdog].timeout % 10,
 655                 (0 != wd_dev.opt_enable) ? "in ENABLED mode" : "");
 656         return(0);
 657 }
 658
 659 /* Timer method called to reset stopped watchdogs--
 660  * because of the PLD bug on CP1400, we cannot mask
 661  * interrupts within the PLD so me must continually
 662  * reset the timers ad infinitum.
 663  */
 664 static void wd_brokentimer(unsigned long data)
 665 {
 666         struct wd_device* pDev = (struct wd_device*)data;
 667         int id, tripped = 0;
 668
 669         /* kill a running timer instance, in case we
 670          * were called directly instead of by kernel timer
 671          */
 672         if(timer_pending(&wd_timer)) {
 673                 del_timer(&wd_timer);
 674         }
 675
 676         for(id = WD0_ID; id < WD_NUMDEVS; ++id) {
 677                 if(pDev->watchdog[id].runstatus & WD_STAT_BSTOP) {
 678                         ++tripped;
 679                         wd_resetbrokentimer(&pDev->watchdog[id]);
 680                 }
 681         }
 682
 683         if(tripped) {
 684                 /* there is at least one timer brokenstopped-- reschedule */
 685                 init_timer(&wd_timer);
 686                 wd_timer.expires = WD_BTIMEOUT;
 687                 add_timer(&wd_timer);
 688         }
 689 }
 690
 691 static int wd_getstatus(struct wd_timer* pTimer)
 692 {
 693         unsigned char stat = wd_readb(&pTimer->regs->status);
 694         unsigned char intr = wd_readb(&wd_dev.regs->pld_regs.intr_mask);
 695         unsigned char ret  = WD_STOPPED;
 696
 697         /* determine STOPPED */
 698         if(0 == stat ) {
 699                 return(ret);
 700         }
 701         /* determine EXPIRED vs FREERUN vs RUNNING */
 702         else if(WD_S_EXPIRED & stat) {
 703                 ret = WD_EXPIRED;
 704         }
 705         else if(WD_S_RUNNING & stat) {
 706                 if(intr & pTimer->intr_mask) {
 707                         ret = WD_FREERUN;
 708                 }
 709                 else {
 710                         /* Fudge WD_EXPIRED status for defective CP1400--
 711                          * IF timer is running
 712                          *      AND brokenstop is set
 713                          *      AND an interrupt has been serviced
 714                          * we are WD_EXPIRED.
 715                          *
 716                          * IF timer is running
 717                          *      AND brokenstop is set
 718                          *      AND no interrupt has been serviced
 719                          * we are WD_FREERUN.
 720                          */
 721                         if(wd_dev.isbaddoggie && (pTimer->runstatus & WD_STAT_BSTOP)) {
 722                                 if(pTimer->runstatus & WD_STAT_SVCD) {
 723                                         ret = WD_EXPIRED;
 724                                 }
 725                                 else {
 726                                         /* we could as well pretend we are expired */
 727                                         ret = WD_FREERUN;
 728                                 }
 729                         }
 730                         else {
 731                                 ret = WD_RUNNING;
 732                         }
 733                 }
 734         }
 735
 736         /* determine SERVICED */
 737         if(pTimer->runstatus & WD_STAT_SVCD) {
 738                 ret |= WD_SERVICED;
 739         }
 740
 741         return(ret);
 742 }
 743
 744 static int __init wd_init(void)
 745 {
 746         int     id;
 747         struct  linux_ebus *ebus = NULL;
 748         struct  linux_ebus_device *edev = NULL;
 749
 750         for_each_ebus(ebus) {
 751                 for_each_ebusdev(edev, ebus) {
 752                         if (!strcmp(edev->prom_name, WD_OBPNAME))
 753                                 goto ebus_done;
 754                 }
 755         }
 756
 757 ebus_done:
 758         if(!edev) {
 759                 printk("%s: unable to locate device\n", WD_OBPNAME);
 760                 return -ENODEV;
 761         }
 762
 763         wd_dev.regs =
 764                 ioremap(edev->resource[0].start, sizeof(struct wd_regblk));
 765
 766         if(NULL == wd_dev.regs) {
 767                 printk("%s: unable to map registers\n", WD_OBPNAME);
 768                 return(-ENODEV);
 769         }
 770
 771         /* initialize device structure from OBP parameters */
 772         wd_dev.irq                      = edev->irqs[0];
 773         wd_dev.opt_enable       = wd_opt_enable();
 774         wd_dev.opt_reboot       = wd_opt_reboot();
 775         wd_dev.opt_timeout      = wd_opt_timeout();
 776         wd_dev.isbaddoggie      = wd_isbroken();
 777
 778         /* disable all interrupts unless watchdog-enabled? == true */
 779         if(! wd_dev.opt_enable) {
 780                 wd_toggleintr(NULL, WD_INTR_OFF);
 781         }
 782
 783         /* register miscellaneous devices */
 784         for(id = WD0_ID; id < WD_NUMDEVS; ++id) {
 785                 if(0 != wd_inittimer(id)) {
 786                         printk("%s%i: unable to initialize\n", WD_OBPNAME, id);
 787                 }
 788         }
 789
 790         /* warn about possible defective PLD */
 791         if(wd_dev.isbaddoggie) {
 792                 init_timer(&wd_timer);
 793                 wd_timer.function       = wd_brokentimer;
 794                 wd_timer.data           = (unsigned long)&wd_dev;
 795                 wd_timer.expires        = WD_BTIMEOUT;
 796
 797                 printk("%s: PLD defect workaround enabled for model %s\n",
 798                         WD_OBPNAME, WD_BADMODEL);
 799         }
 800         return(0);
 801 }
 802
 803 static void __exit wd_cleanup(void)
 804 {
 805         int id;
 806
 807         /* if 'watchdog-enable?' == TRUE, timers are not stopped
 808          * when module is unloaded.  All brokenstopped timers will
 809          * also now eventually trip.
 810          */
 811         for(id = WD0_ID; id < WD_NUMDEVS; ++id) {
 812                 if(WD_S_RUNNING == wd_readb(&wd_dev.watchdog[id].regs->status)) {
 813                         if(wd_dev.opt_enable) {
 814                                 printk(KERN_WARNING "%s%i: timer not stopped at release\n",
 815                                         WD_OBPNAME, id);
 816                         }
 817                         else {
 818                                 wd_stoptimer(&wd_dev.watchdog[id]);
 819                                 if(wd_dev.watchdog[id].runstatus & WD_STAT_BSTOP) {
 820                                         wd_resetbrokentimer(&wd_dev.watchdog[id]);
 821                                         printk(KERN_WARNING
 822                                                         "%s%i: defect workaround disabled at release, "\
 823                                                         "timer expires in ~%01i sec\n",
 824                                                         WD_OBPNAME, id,
 825                                                         wd_readw(&wd_dev.watchdog[id].regs->limit) / 10);
 826                                 }
 827                         }
 828                 }
 829         }
 830
 831         if(wd_dev.isbaddoggie && timer_pending(&wd_timer)) {
 832                 del_timer(&wd_timer);
 833         }
 834         if(0 != (wd_dev.watchdog[WD0_ID].runstatus & WD_STAT_INIT)) {
 835                 misc_deregister(&wd0_miscdev);
 836         }
 837         if(0 != (wd_dev.watchdog[WD1_ID].runstatus & WD_STAT_INIT)) {
 838                 misc_deregister(&wd1_miscdev);
 839         }
 840         if(0 != (wd_dev.watchdog[WD2_ID].runstatus & WD_STAT_INIT)) {
 841                 misc_deregister(&wd2_miscdev);
 842         }
 843         if(0 != wd_dev.initialized) {
 844                 free_irq(wd_dev.irq, (void *)wd_dev.regs);
 845         }
 846         iounmap(wd_dev.regs);
 847 }
 848
 849 module_init(wd_init);
 850 module_exit(wd_cleanup);