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