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