drivers/sbus/char/cpwatchdog.c

   1 /* cpwatchdog.c - driver implementation for hardware watchdog
   2  * timers found on Sun Microsystems CP1400 and CP1500 boards.
   3  *
   4  * This device supports both the generic Linux watchdog
   5  * interface and Solaris-compatible ioctls as best it is
   6  * able.
   7  *
   8  * NOTE:        CP1400 systems appear to have a defective intr_mask
   9  *                      register on the PLD, preventing the disabling of
  10  *                      timer interrupts.  We use a timer to periodically
  11  *                      reset 'stopped' watchdogs on affected platforms.
  12  *
  13  * Copyright (c) 2000 Eric Brower (ebrower@usa.net)
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/fs.h>
  19 #include <linux/errno.h>
  20 #include <linux/major.h>
  21 #include <linux/init.h>
  22 #include <linux/miscdevice.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/ioport.h>
  25 #include <linux/timer.h>
  26 #include <linux/smp_lock.h>
  27 #include <asm/irq.h>
  28 #include <asm/ebus.h>
  29 #include <asm/oplib.h>
  30 #include <asm/uaccess.h>
  31
  32 #include <asm/watchdog.h>
  33
  34 #define WD_OBPNAME      "watchdog"
  35 #define WD_BADMODEL "SUNW,501-5336"
  36 #define WD_BTIMEOUT     (jiffies + (HZ * 1000))
  37 #define WD_BLIMIT       0xFFFF
  38
  39 #define WD0_DEVNAME "watchdog0"
  40 #define WD1_DEVNAME "watchdog1"
  41 #define WD2_DEVNAME "watchdog2"
  42
  43 #define WD0_MINOR       212
  44 #define WD1_MINOR       213
  45 #define WD2_MINOR       214
  46
  47
  48 /* Internal driver definitions
  49  */
  50 #define WD0_ID                  0               /* Watchdog0                                            */
  51 #define WD1_ID                  1               /* Watchdog1                                            */
  52 #define WD2_ID                  2               /* Watchdog2                                            */
  53 #define WD_NUMDEVS              3               /* Device contains 3 timers                     */
  54
  55 #define WD_INTR_OFF             0               /* Interrupt disable value                      */
  56 #define WD_INTR_ON              1               /* Interrupt enable value                       */
  57
  58 #define WD_STAT_INIT    0x01    /* Watchdog timer is initialized        */
  59 #define WD_STAT_BSTOP   0x02    /* Watchdog timer is brokenstopped      */
  60 #define WD_STAT_SVCD    0x04    /* Watchdog interrupt occurred          */
  61
  62 /* Register value definitions
  63  */
  64 #define WD0_INTR_MASK   0x01    /* Watchdog device interrupt masks      */
  65 #define WD1_INTR_MASK   0x02
  66 #define WD2_INTR_MASK   0x04
  67
  68 #define WD_S_RUNNING    0x01    /* Watchdog device status running       */
  69 #define WD_S_EXPIRED    0x02    /* Watchdog device status expired       */
  70
  71 /* Sun uses Altera PLD EPF8820ATC144-4
  72  * providing three hardware watchdogs:
  73  *
  74  *      1) RIC - sends an interrupt when triggered
  75  *      2) XIR - asserts XIR_B_RESET when triggered, resets CPU
  76  *      3) POR - asserts POR_B_RESET when triggered, resets CPU, backplane, board
  77  *
  78  *** Timer register block definition (struct wd_timer_regblk)
  79  *
  80  * dcntr and limit registers (halfword access):
  81  * -------------------
  82  * | 15 | ...| 1 | 0 |
  83  * -------------------
  84  * |-  counter val  -|
  85  * -------------------
  86  * dcntr -      Current 16-bit downcounter value.
  87  *                      When downcounter reaches '0' watchdog expires.
  88  *                      Reading this register resets downcounter with 'limit' value.
  89  * limit -      16-bit countdown value in 1/10th second increments.
  90  *                      Writing this register begins countdown with input value.
  91  *                      Reading from this register does not affect counter.
  92  * NOTES:       After watchdog reset, dcntr and limit contain '1'
  93  *
  94  * status register (byte access):
  95  * ---------------------------
  96  * | 7 | ... | 2 |  1  |  0  |
  97  * --------------+------------
  98  * |-   UNUSED  -| EXP | RUN |
  99  * ---------------------------
 100  * status-      Bit 0 - Watchdog is running
 101  *                      Bit 1 - Watchdog has expired
 102  *
 103  *** PLD register block definition (struct wd_pld_regblk)
 104  *
 105  * intr_mask register (byte access):
 106  * ---------------------------------
 107  * | 7 | ... | 3 |  2  |  1  |  0  |
 108  * +-------------+------------------
 109  * |-   UNUSED  -| WD3 | WD2 | WD1 |
 110  * ---------------------------------
 111  * WD3 -  1 == Interrupt disabled for watchdog 3
 112  * WD2 -  1 == Interrupt disabled for watchdog 2
 113  * WD1 -  1 == Interrupt disabled for watchdog 1
 114  *
 115  * pld_status register (byte access):
 116  * UNKNOWN, MAGICAL MYSTERY REGISTER
 117  *
 118  */
 119 #define WD_TIMER_REGSZ  16
 120 #define WD0_OFF         0
 121 #define WD1_OFF         (WD_TIMER_REGSZ * 1)
 122 #define WD2_OFF         (WD_TIMER_REGSZ * 2)
 123 #define PLD_OFF         (WD_TIMER_REGSZ * 3)
 124
 125 #define WD_DCNTR        0x00
 126 #define WD_LIMIT        0x04
 127 #define WD_STATUS       0x08
 128
 129 #define PLD_IMASK       (PLD_OFF + 0x00)
 130 #define PLD_STATUS      (PLD_OFF + 0x04)
 131
 132 /* Individual timer structure
 133  */
 134 struct wd_timer {
 135         __u16                   timeout;
 136         __u8                    intr_mask;
 137         unsigned char           runstatus;
 138         void __iomem            *regs;
 139 };
 140
 141 /* Device structure
 142  */
 143 struct wd_device {
 144         int                             irq;
 145         spinlock_t              lock;
 146         unsigned char   isbaddoggie;    /* defective PLD */
 147         unsigned char   opt_enable;
 148         unsigned char   opt_reboot;
 149         unsigned short  opt_timeout;
 150         unsigned char   initialized;
 151         struct wd_timer watchdog[WD_NUMDEVS];
 152         void __iomem    *regs;
 153 };
 154
 155 static struct wd_device wd_dev = {
 156                 0, SPIN_LOCK_UNLOCKED, 0, 0, 0, 0,
 157 };
 158
 159 static struct timer_list wd_timer;
 160
 161 static int wd0_timeout = 0;
 162 static int wd1_timeout = 0;
 163 static int wd2_timeout = 0;
 164
 165 #ifdef MODULE
 166 module_param    (wd0_timeout, int, 0);
 167 MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs");
 168 module_param    (wd1_timeout, int, 0);
 169 MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs");
 170 module_param    (wd2_timeout, int, 0);
 171 MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs");
 172
 173 MODULE_AUTHOR
 174         ("Eric Brower <ebrower@usa.net>");
 175 MODULE_DESCRIPTION
 176         ("Hardware watchdog driver for Sun Microsystems CP1400/1500");
 177 MODULE_LICENSE("GPL");
 178 MODULE_SUPPORTED_DEVICE
 179         ("watchdog");
 180 #endif /* ifdef MODULE */
 181
 182 /* Forward declarations of internal methods
 183  */
 184 #ifdef WD_DEBUG
 185 static void wd_dumpregs(void);
 186 #endif
 187 static irqreturn_t wd_interrupt(int irq, void *dev_id);
 188 static void wd_toggleintr(struct wd_timer* pTimer, int enable);
 189 static void wd_pingtimer(struct wd_timer* pTimer);
 190 static void wd_starttimer(struct wd_timer* pTimer);
 191 static void wd_resetbrokentimer(struct wd_timer* pTimer);
 192 static void wd_stoptimer(struct wd_timer* pTimer);
 193 static void wd_brokentimer(unsigned long data);
 194 static int  wd_getstatus(struct wd_timer* pTimer);
 195
 196 /* PLD expects words to be written in LSB format,
 197  * so we must flip all words prior to writing them to regs
 198  */
 199 static inline unsigned short flip_word(unsigned short word)
 200 {
 201         return ((word & 0xff) << 8) | ((word >> 8) & 0xff);
 202 }
 203
 204 #define wd_writew(val, addr)    (writew(flip_word(val), addr))
 205 #define wd_readw(addr)                  (flip_word(readw(addr)))
 206 #define wd_writeb(val, addr)    (writeb(val, addr))
 207 #define wd_readb(addr)                  (readb(addr))
 208
 209
 210 /* CP1400s seem to have broken PLD implementations--
 211  * the interrupt_mask register cannot be written, so
 212  * no timer interrupts can be masked within the PLD.
 213  */
 214 static inline int wd_isbroken(void)
 215 {
 216         /* we could test this by read/write/read/restore
 217          * on the interrupt mask register only if OBP
 218          * 'watchdog-enable?' == FALSE, but it seems
 219          * ubiquitous on CP1400s
 220          */
 221         char val[32];
 222         prom_getproperty(prom_root_node, "model", val, sizeof(val));
 223         return((!strcmp(val, WD_BADMODEL)) ? 1 : 0);
 224 }
 225
 226 /* Retrieve watchdog-enable? option from OBP
 227  * Returns 0 if false, 1 if true
 228  */
 229 static inline int wd_opt_enable(void)
 230 {
 231         int opt_node;
 232
 233         opt_node = prom_getchild(prom_root_node);
 234         opt_node = prom_searchsiblings(opt_node, "options");
 235         return((-1 == prom_getint(opt_node, "watchdog-enable?")) ? 0 : 1);
 236 }
 237
 238 /* Retrieve watchdog-reboot? option from OBP
 239  * Returns 0 if false, 1 if true
 240  */
 241 static inline int wd_opt_reboot(void)
 242 {
 243         int opt_node;
 244
 245         opt_node = prom_getchild(prom_root_node);
 246         opt_node = prom_searchsiblings(opt_node, "options");
 247         return((-1 == prom_getint(opt_node, "watchdog-reboot?")) ? 0 : 1);
 248 }
 249
 250 /* Retrieve watchdog-timeout option from OBP
 251  * Returns OBP value, or 0 if not located
 252  */
 253 static inline int wd_opt_timeout(void)
 254 {
 255         int opt_node;
 256         char value[32];
 257         char *p = value;
 258
 259         opt_node = prom_getchild(prom_root_node);
 260         opt_node = prom_searchsiblings(opt_node, "options");
 261         opt_node = prom_getproperty(opt_node,
 262                                                                 "watchdog-timeout",
 263                                                                 value,
 264                                                                 sizeof(value));
 265         if(-1 != opt_node) {
 266                 /* atoi implementation */
 267                 for(opt_node = 0; /* nop */; p++) {
 268                         if(*p >= '0' && *p <= '9') {
 269                                 opt_node = (10*opt_node)+(*p-'0');
 270                         }
 271                         else {
 272                                 break;
 273                         }
 274                 }
 275         }
 276         return((-1 == opt_node) ? (0) : (opt_node));
 277 }
 278
 279 static int wd_open(struct inode *inode, struct file *f)
 280 {
 281         switch(iminor(inode))
 282         {
 283                 case WD0_MINOR:
 284                         f->private_data = &wd_dev.watchdog[WD0_ID];
 285                         break;
 286                 case WD1_MINOR:
 287                         f->private_data = &wd_dev.watchdog[WD1_ID];
 288                         break;
 289                 case WD2_MINOR:
 290                         f->private_data = &wd_dev.watchdog[WD2_ID];
 291                         break;
 292                 default:
 293                         return(-ENODEV);
 294         }
 295
 296         /* Register IRQ on first open of device */
 297         if(0 == wd_dev.initialized)
 298         {
 299                 if (request_irq(wd_dev.irq,
 300                                                 &wd_interrupt,
 301                                                 IRQF_SHARED,
 302                                                 WD_OBPNAME,
 303                                                 (void *)wd_dev.regs)) {
 304                         printk("%s: Cannot register IRQ %d\n",
 305                                 WD_OBPNAME, wd_dev.irq);
 306                         return(-EBUSY);
 307                 }
 308                 wd_dev.initialized = 1;
 309         }
 310
 311         return(nonseekable_open(inode, f));
 312 }
 313
 314 static int wd_release(struct inode *inode, struct file *file)
 315 {
 316         return 0;
 317 }
 318
 319 static int wd_ioctl(struct inode *inode, struct file *file,
 320                      unsigned int cmd, unsigned long arg)
 321 {
 322         int     setopt                          = 0;
 323         struct  wd_timer* pTimer        = (struct wd_timer*)file->private_data;
 324         void __user *argp = (void __user *)arg;
 325         struct  watchdog_info info      = {
 326                 0,
 327                 0,
 328                 "Altera EPF8820ATC144-4"
 329         };
 330
 331         if(NULL == pTimer) {
 332                 return(-EINVAL);
 333         }
 334
 335         switch(cmd)
 336         {
 337                 /* Generic Linux IOCTLs */
 338                 case WDIOC_GETSUPPORT:
 339                         if(copy_to_user(argp, &info, sizeof(struct watchdog_info))) {
 340                                 return(-EFAULT);
 341                         }
 342                         break;
 343                 case WDIOC_GETSTATUS:
 344                 case WDIOC_GETBOOTSTATUS:
 345                         if (put_user(0, (int __user *)argp))
 346                                 return -EFAULT;
 347                         break;
 348                 case WDIOC_KEEPALIVE:
 349                         wd_pingtimer(pTimer);
 350                         break;
 351                 case WDIOC_SETOPTIONS:
 352                         if(copy_from_user(&setopt, argp, sizeof(unsigned int))) {
 353                                 return -EFAULT;
 354                         }
 355                         if(setopt & WDIOS_DISABLECARD) {
 356                                 if(wd_dev.opt_enable) {
 357                                         printk(
 358                                                 "%s: cannot disable watchdog in ENABLED mode\n",
 359                                                 WD_OBPNAME);
 360                                         return(-EINVAL);
 361                                 }
 362                                 wd_stoptimer(pTimer);
 363                         }
 364                         else if(setopt & WDIOS_ENABLECARD) {
 365                                 wd_starttimer(pTimer);
 366                         }
 367                         else {
 368                                 return(-EINVAL);
 369                         }
 370                         break;
 371                 /* Solaris-compatible IOCTLs */
 372                 case WIOCGSTAT:
 373                         setopt = wd_getstatus(pTimer);
 374                         if(copy_to_user(argp, &setopt, sizeof(unsigned int))) {
 375                                 return(-EFAULT);
 376                         }
 377                         break;
 378                 case WIOCSTART:
 379                         wd_starttimer(pTimer);
 380                         break;
 381                 case WIOCSTOP:
 382                         if(wd_dev.opt_enable) {
 383                                 printk("%s: cannot disable watchdog in ENABLED mode\n",
 384                                         WD_OBPNAME);
 385                                 return(-EINVAL);
 386                         }
 387                         wd_stoptimer(pTimer);
 388                         break;
 389                 default:
 390                         return(-EINVAL);
 391         }
 392         return(0);
 393 }
 394
 395 static long wd_compat_ioctl(struct file *file, unsigned int cmd,
 396                 unsigned long arg)
 397 {
 398         int rval = -ENOIOCTLCMD;
 399
 400         switch (cmd) {
 401         /* solaris ioctls are specific to this driver */
 402         case WIOCSTART:
 403         case WIOCSTOP:
 404         case WIOCGSTAT:
 405                 lock_kernel();
 406                 rval = wd_ioctl(file->f_path.dentry->d_inode, file, cmd, arg);
 407                 unlock_kernel();
 408                 break;
 409         /* everything else is handled by the generic compat layer */
 410         default:
 411                 break;
 412         }
 413
 414         return rval;
 415 }
 416
 417 static ssize_t wd_write(struct file     *file,
 418                         const char      __user *buf,
 419                         size_t          count,
 420                         loff_t          *ppos)
 421 {
 422         struct wd_timer* pTimer = (struct wd_timer*)file->private_data;
 423
 424         if(NULL == pTimer) {
 425                 return(-EINVAL);
 426         }
 427
 428         if (count) {
 429                 wd_pingtimer(pTimer);
 430                 return 1;
 431         }
 432         return 0;
 433 }
 434
 435 static ssize_t wd_read(struct file * file, char __user *buffer,
 436                         size_t count, loff_t *ppos)
 437 {
 438 #ifdef WD_DEBUG
 439         wd_dumpregs();
 440         return(0);
 441 #else
 442         return(-EINVAL);
 443 #endif /* ifdef WD_DEBUG */
 444 }
 445
 446 static irqreturn_t wd_interrupt(int irq, void *dev_id)
 447 {
 448         /* Only WD0 will interrupt-- others are NMI and we won't
 449          * see them here....
 450          */
 451         spin_lock_irq(&wd_dev.lock);
 452         if((unsigned long)wd_dev.regs == (unsigned long)dev_id)
 453         {
 454                 wd_stoptimer(&wd_dev.watchdog[WD0_ID]);
 455                 wd_dev.watchdog[WD0_ID].runstatus |=  WD_STAT_SVCD;
 456         }
 457         spin_unlock_irq(&wd_dev.lock);
 458         return IRQ_HANDLED;
 459 }
 460
 461 static const struct file_operations wd_fops = {
 462         .owner =        THIS_MODULE,
 463         .ioctl =        wd_ioctl,
 464         .compat_ioctl = wd_compat_ioctl,
 465         .open =         wd_open,
 466         .write =        wd_write,
 467         .read =         wd_read,
 468         .release =      wd_release,
 469 };
 470
 471 static struct miscdevice wd0_miscdev = { WD0_MINOR, WD0_DEVNAME, &wd_fops };
 472 static struct miscdevice wd1_miscdev = { WD1_MINOR, WD1_DEVNAME, &wd_fops };
 473 static struct miscdevice wd2_miscdev = { WD2_MINOR, WD2_DEVNAME, &wd_fops };
 474
 475 #ifdef WD_DEBUG
 476 static void wd_dumpregs(void)
 477 {
 478         /* Reading from downcounters initiates watchdog countdown--
 479          * Example is included below for illustration purposes.
 480          */
 481         int i;
 482         printk("%s: dumping register values\n", WD_OBPNAME);
 483         for(i = WD0_ID; i < WD_NUMDEVS; ++i) {
 484                         /* printk("\t%s%i: dcntr  at 0x%lx: 0x%x\n",
 485                          *      WD_OBPNAME,
 486                          *      i,
 487                          *      (unsigned long)(&wd_dev.watchdog[i].regs->dcntr),
 488                          *      readw(&wd_dev.watchdog[i].regs->dcntr));
 489                          */
 490                         printk("\t%s%i: limit  at 0x%lx: 0x%x\n",
 491                                 WD_OBPNAME,
 492                                 i,
 493                                 (unsigned long)(&wd_dev.watchdog[i].regs->limit),
 494                                 readw(&wd_dev.watchdog[i].regs->limit));
 495                         printk("\t%s%i: status at 0x%lx: 0x%x\n",
 496                                 WD_OBPNAME,
 497                                 i,
 498                                 (unsigned long)(&wd_dev.watchdog[i].regs->status),
 499                                 readb(&wd_dev.watchdog[i].regs->status));
 500                         printk("\t%s%i: driver status: 0x%x\n",
 501                                 WD_OBPNAME,
 502                                 i,
 503                                 wd_getstatus(&wd_dev.watchdog[i]));
 504         }
 505         printk("\tintr_mask  at %p: 0x%x\n",
 506                 wd_dev.regs + PLD_IMASK,
 507                 readb(wd_dev.regs + PLD_IMASK));
 508         printk("\tpld_status at %p: 0x%x\n",
 509                 wd_dev.regs + PLD_STATUS,
 510                 readb(wd_dev.regs + PLD_STATUS));
 511 }
 512 #endif
 513
 514 /* Enable or disable watchdog interrupts
 515  * Because of the CP1400 defect this should only be
 516  * called during initialzation or by wd_[start|stop]timer()
 517  *
 518  * pTimer       - pointer to timer device, or NULL to indicate all timers
 519  * enable       - non-zero to enable interrupts, zero to disable
 520  */
 521 static void wd_toggleintr(struct wd_timer* pTimer, int enable)
 522 {
 523         unsigned char curregs = wd_readb(wd_dev.regs + PLD_IMASK);
 524         unsigned char setregs =
 525                 (NULL == pTimer) ?
 526                         (WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) :
 527                         (pTimer->intr_mask);
 528
 529         (WD_INTR_ON == enable) ?
 530                 (curregs &= ~setregs):
 531                 (curregs |=  setregs);
 532
 533         wd_writeb(curregs, wd_dev.regs + PLD_IMASK);
 534         return;
 535 }
 536
 537 /* Reset countdown timer with 'limit' value and continue countdown.
 538  * This will not start a stopped timer.
 539  *
 540  * pTimer       - pointer to timer device
 541  */
 542 static void wd_pingtimer(struct wd_timer* pTimer)
 543 {
 544         if (wd_readb(pTimer->regs + WD_STATUS) & WD_S_RUNNING) {
 545                 wd_readw(pTimer->regs + WD_DCNTR);
 546         }
 547 }
 548
 549 /* Stop a running watchdog timer-- the timer actually keeps
 550  * running, but the interrupt is masked so that no action is
 551  * taken upon expiration.
 552  *
 553  * pTimer       - pointer to timer device
 554  */
 555 static void wd_stoptimer(struct wd_timer* pTimer)
 556 {
 557         if(wd_readb(pTimer->regs + WD_STATUS) & WD_S_RUNNING) {
 558                 wd_toggleintr(pTimer, WD_INTR_OFF);
 559
 560                 if(wd_dev.isbaddoggie) {
 561                         pTimer->runstatus |= WD_STAT_BSTOP;
 562                         wd_brokentimer((unsigned long)&wd_dev);
 563                 }
 564         }
 565 }
 566
 567 /* Start a watchdog timer with the specified limit value
 568  * If the watchdog is running, it will be restarted with
 569  * the provided limit value.
 570  *
 571  * This function will enable interrupts on the specified
 572  * watchdog.
 573  *
 574  * pTimer       - pointer to timer device
 575  * limit        - limit (countdown) value in 1/10th seconds
 576  */
 577 static void wd_starttimer(struct wd_timer* pTimer)
 578 {
 579         if(wd_dev.isbaddoggie) {
 580                 pTimer->runstatus &= ~WD_STAT_BSTOP;
 581         }
 582         pTimer->runstatus &= ~WD_STAT_SVCD;
 583
 584         wd_writew(pTimer->timeout, pTimer->regs + WD_LIMIT);
 585         wd_toggleintr(pTimer, WD_INTR_ON);
 586 }
 587
 588 /* Restarts timer with maximum limit value and
 589  * does not unset 'brokenstop' value.
 590  */
 591 static void wd_resetbrokentimer(struct wd_timer* pTimer)
 592 {
 593         wd_toggleintr(pTimer, WD_INTR_ON);
 594         wd_writew(WD_BLIMIT, pTimer->regs + WD_LIMIT);
 595 }
 596
 597 /* Timer device initialization helper.
 598  * Returns 0 on success, other on failure
 599  */
 600 static int wd_inittimer(int whichdog)
 601 {
 602         struct miscdevice                               *whichmisc;
 603         void __iomem *whichregs;
 604         char                                                    whichident[8];
 605         int                                                             whichmask;
 606         __u16                                                   whichlimit;
 607
 608         switch(whichdog)
 609         {
 610                 case WD0_ID:
 611                         whichmisc = &wd0_miscdev;
 612                         strcpy(whichident, "RIC");
 613                         whichregs = wd_dev.regs + WD0_OFF;
 614                         whichmask = WD0_INTR_MASK;
 615                         whichlimit= (0 == wd0_timeout)  ?
 616                                                 (wd_dev.opt_timeout):
 617                                                 (wd0_timeout);
 618                         break;
 619                 case WD1_ID:
 620                         whichmisc = &wd1_miscdev;
 621                         strcpy(whichident, "XIR");
 622                         whichregs = wd_dev.regs + WD1_OFF;
 623                         whichmask = WD1_INTR_MASK;
 624                         whichlimit= (0 == wd1_timeout)  ?
 625                                                 (wd_dev.opt_timeout):
 626                                                 (wd1_timeout);
 627                         break;
 628                 case WD2_ID:
 629                         whichmisc = &wd2_miscdev;
 630                         strcpy(whichident, "POR");
 631                         whichregs = wd_dev.regs + WD2_OFF;
 632                         whichmask = WD2_INTR_MASK;
 633                         whichlimit= (0 == wd2_timeout)  ?
 634                                                 (wd_dev.opt_timeout):
 635                                                 (wd2_timeout);
 636                         break;
 637                 default:
 638                         printk("%s: %s: invalid watchdog id: %i\n",
 639                                 WD_OBPNAME, __FUNCTION__, whichdog);
 640                         return(1);
 641         }
 642         if(0 != misc_register(whichmisc))
 643         {
 644                 return(1);
 645         }
 646         wd_dev.watchdog[whichdog].regs                  = whichregs;
 647         wd_dev.watchdog[whichdog].timeout               = whichlimit;
 648         wd_dev.watchdog[whichdog].intr_mask             = whichmask;
 649         wd_dev.watchdog[whichdog].runstatus     &= ~WD_STAT_BSTOP;
 650         wd_dev.watchdog[whichdog].runstatus     |= WD_STAT_INIT;
 651
 652         printk("%s%i: %s hardware watchdog [%01i.%i sec] %s\n",
 653                 WD_OBPNAME,
 654                 whichdog,
 655                 whichident,
 656                 wd_dev.watchdog[whichdog].timeout / 10,
 657                 wd_dev.watchdog[whichdog].timeout % 10,
 658                 (0 != wd_dev.opt_enable) ? "in ENABLED mode" : "");
 659         return(0);
 660 }
 661
 662 /* Timer method called to reset stopped watchdogs--
 663  * because of the PLD bug on CP1400, we cannot mask
 664  * interrupts within the PLD so me must continually
 665  * reset the timers ad infinitum.
 666  */
 667 static void wd_brokentimer(unsigned long data)
 668 {
 669         struct wd_device* pDev = (struct wd_device*)data;
 670         int id, tripped = 0;
 671
 672         /* kill a running timer instance, in case we
 673          * were called directly instead of by kernel timer
 674          */
 675         if(timer_pending(&wd_timer)) {
 676                 del_timer(&wd_timer);
 677         }
 678
 679         for(id = WD0_ID; id < WD_NUMDEVS; ++id) {
 680                 if(pDev->watchdog[id].runstatus & WD_STAT_BSTOP) {
 681                         ++tripped;
 682                         wd_resetbrokentimer(&pDev->watchdog[id]);
 683                 }
 684         }
 685
 686         if(tripped) {
 687                 /* there is at least one timer brokenstopped-- reschedule */
 688                 init_timer(&wd_timer);
 689                 wd_timer.expires = WD_BTIMEOUT;
 690                 add_timer(&wd_timer);
 691         }
 692 }
 693
 694 static int wd_getstatus(struct wd_timer* pTimer)
 695 {
 696         unsigned char stat = wd_readb(pTimer->regs + WD_STATUS);
 697         unsigned char intr = wd_readb(wd_dev.regs + PLD_IMASK);
 698         unsigned char ret  = WD_STOPPED;
 699
 700         /* determine STOPPED */
 701         if(0 == stat ) {
 702                 return(ret);
 703         }
 704         /* determine EXPIRED vs FREERUN vs RUNNING */
 705         else if(WD_S_EXPIRED & stat) {
 706                 ret = WD_EXPIRED;
 707         }
 708         else if(WD_S_RUNNING & stat) {
 709                 if(intr & pTimer->intr_mask) {
 710                         ret = WD_FREERUN;
 711                 }
 712                 else {
 713                         /* Fudge WD_EXPIRED status for defective CP1400--
 714                          * IF timer is running
 715                          *      AND brokenstop is set
 716                          *      AND an interrupt has been serviced
 717                          * we are WD_EXPIRED.
 718                          *
 719                          * IF timer is running
 720                          *      AND brokenstop is set
 721                          *      AND no interrupt has been serviced
 722                          * we are WD_FREERUN.
 723                          */
 724                         if(wd_dev.isbaddoggie && (pTimer->runstatus & WD_STAT_BSTOP)) {
 725                                 if(pTimer->runstatus & WD_STAT_SVCD) {
 726                                         ret = WD_EXPIRED;
 727                                 }
 728                                 else {
 729                                         /* we could as well pretend we are expired */
 730                                         ret = WD_FREERUN;
 731                                 }
 732                         }
 733                         else {
 734                                 ret = WD_RUNNING;
 735                         }
 736                 }
 737         }
 738
 739         /* determine SERVICED */
 740         if(pTimer->runstatus & WD_STAT_SVCD) {
 741                 ret |= WD_SERVICED;
 742         }
 743
 744         return(ret);
 745 }
 746
 747 static int __init wd_init(void)
 748 {
 749         int     id;
 750         struct  linux_ebus *ebus = NULL;
 751         struct  linux_ebus_device *edev = NULL;
 752
 753         for_each_ebus(ebus) {
 754                 for_each_ebusdev(edev, ebus) {
 755                         if (!strcmp(edev->ofdev.node->name, WD_OBPNAME))
 756                                 goto ebus_done;
 757                 }
 758         }
 759
 760 ebus_done:
 761         if(!edev) {
 762                 printk("%s: unable to locate device\n", WD_OBPNAME);
 763                 return -ENODEV;
 764         }
 765
 766         wd_dev.regs =
 767                 ioremap(edev->resource[0].start, 4 * WD_TIMER_REGSZ); /* ? */
 768
 769         if(NULL == wd_dev.regs) {
 770                 printk("%s: unable to map registers\n", WD_OBPNAME);
 771                 return(-ENODEV);
 772         }
 773
 774         /* initialize device structure from OBP parameters */
 775         wd_dev.irq                      = edev->irqs[0];
 776         wd_dev.opt_enable       = wd_opt_enable();
 777         wd_dev.opt_reboot       = wd_opt_reboot();
 778         wd_dev.opt_timeout      = wd_opt_timeout();
 779         wd_dev.isbaddoggie      = wd_isbroken();
 780
 781         /* disable all interrupts unless watchdog-enabled? == true */
 782         if(! wd_dev.opt_enable) {
 783                 wd_toggleintr(NULL, WD_INTR_OFF);
 784         }
 785
 786         /* register miscellaneous devices */
 787         for(id = WD0_ID; id < WD_NUMDEVS; ++id) {
 788                 if(0 != wd_inittimer(id)) {
 789                         printk("%s%i: unable to initialize\n", WD_OBPNAME, id);
 790                 }
 791         }
 792
 793         /* warn about possible defective PLD */
 794         if(wd_dev.isbaddoggie) {
 795                 init_timer(&wd_timer);
 796                 wd_timer.function       = wd_brokentimer;
 797                 wd_timer.data           = (unsigned long)&wd_dev;
 798                 wd_timer.expires        = WD_BTIMEOUT;
 799
 800                 printk("%s: PLD defect workaround enabled for model %s\n",
 801                         WD_OBPNAME, WD_BADMODEL);
 802         }
 803         return(0);
 804 }
 805
 806 static void __exit wd_cleanup(void)
 807 {
 808         int id;
 809
 810         /* if 'watchdog-enable?' == TRUE, timers are not stopped
 811          * when module is unloaded.  All brokenstopped timers will
 812          * also now eventually trip.
 813          */
 814         for(id = WD0_ID; id < WD_NUMDEVS; ++id) {
 815                 if(WD_S_RUNNING == wd_readb(wd_dev.watchdog[id].regs + WD_STATUS)) {
 816                         if(wd_dev.opt_enable) {
 817                                 printk(KERN_WARNING "%s%i: timer not stopped at release\n",
 818                                         WD_OBPNAME, id);
 819                         }
 820                         else {
 821                                 wd_stoptimer(&wd_dev.watchdog[id]);
 822                                 if(wd_dev.watchdog[id].runstatus & WD_STAT_BSTOP) {
 823                                         wd_resetbrokentimer(&wd_dev.watchdog[id]);
 824                                         printk(KERN_WARNING
 825                                                         "%s%i: defect workaround disabled at release, "\
 826                                                         "timer expires in ~%01i sec\n",
 827                                                         WD_OBPNAME, id,
 828                                                         wd_readw(wd_dev.watchdog[id].regs + WD_LIMIT) / 10);
 829                                 }
 830                         }
 831                 }
 832         }
 833
 834         if(wd_dev.isbaddoggie && timer_pending(&wd_timer)) {
 835                 del_timer(&wd_timer);
 836         }
 837         if(0 != (wd_dev.watchdog[WD0_ID].runstatus & WD_STAT_INIT)) {
 838                 misc_deregister(&wd0_miscdev);
 839         }
 840         if(0 != (wd_dev.watchdog[WD1_ID].runstatus & WD_STAT_INIT)) {
 841                 misc_deregister(&wd1_miscdev);
 842         }
 843         if(0 != (wd_dev.watchdog[WD2_ID].runstatus & WD_STAT_INIT)) {
 844                 misc_deregister(&wd2_miscdev);
 845         }
 846         if(0 != wd_dev.initialized) {
 847                 free_irq(wd_dev.irq, (void *)wd_dev.regs);
 848         }
 849         iounmap(wd_dev.regs);
 850 }
 851
 852 module_init(wd_init);
 853 module_exit(wd_cleanup);