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/version.h>
  21 #include <linux/fs.h>
  22 #include <linux/errno.h>
  23 #include <linux/major.h>
  24 #include <linux/init.h>
  25 #include <linux/miscdevice.h>
  26 #include <linux/sched.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/ioport.h>
  29 #include <linux/timer.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 struct wd_timer_regblk {
 123         volatile __u16  dcntr;          /* down counter         - hw    */
 124         volatile __u16  dcntr_pad;
 125         volatile __u16  limit;          /* limit register       - hw    */
 126         volatile __u16  limit_pad;
 127         volatile __u8   status;         /* status register      - b             */
 128         volatile __u8   status_pad;
 129         volatile __u16  status_pad2;
 130         volatile __u32  pad32;          /* yet more padding                     */
 131 };
 132
 133 struct wd_pld_regblk {
 134         volatile __u8   intr_mask;      /* interrupt mask       - b             */
 135         volatile __u8   intr_mask_pad;
 136         volatile __u16  intr_mask_pad2;
 137         volatile __u8   status;         /* device status        - b             */
 138         volatile __u8   status_pad;
 139         volatile __u16  status_pad2;
 140 };
 141
 142 struct wd_regblk {
 143         volatile struct wd_timer_regblk         wd0_regs;
 144         volatile struct wd_timer_regblk         wd1_regs;
 145         volatile struct wd_timer_regblk         wd2_regs;
 146         volatile struct wd_pld_regblk           pld_regs;
 147 };
 148
 149 /* Individual timer structure
 150  */
 151 struct wd_timer {
 152         __u16                   timeout;
 153         __u8                    intr_mask;
 154         unsigned char   runstatus;
 155         volatile struct wd_timer_regblk* regs;
 156 };
 157
 158 /* Device structure
 159  */
 160 struct wd_device {
 161         int                             irq;
 162         spinlock_t              lock;
 163         unsigned char   isbaddoggie;    /* defective PLD */
 164         unsigned char   opt_enable;
 165         unsigned char   opt_reboot;
 166         unsigned short  opt_timeout;
 167         unsigned char   initialized;
 168         struct wd_timer watchdog[WD_NUMDEVS];
 169         volatile struct wd_regblk* regs;
 170 };
 171
 172 static struct wd_device wd_dev = {
 173                 0, SPIN_LOCK_UNLOCKED, 0, 0, 0, 0,
 174 };
 175
 176 static struct timer_list wd_timer;
 177
 178 static int wd0_timeout = 0;
 179 static int wd1_timeout = 0;
 180 static int wd2_timeout = 0;
 181
 182 #ifdef MODULE
 183 EXPORT_NO_SYMBOLS;
 184
 185 MODULE_PARM             (wd0_timeout, "i");
 186 MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs");
 187 MODULE_PARM     (wd1_timeout, "i");
 188 MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs");
 189 MODULE_PARM     (wd2_timeout, "i");
 190 MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs");
 191
 192 MODULE_AUTHOR
 193         ("Eric Brower <ebrower@usa.net>");
 194 MODULE_DESCRIPTION
 195         ("Hardware watchdog driver for Sun Microsystems CP1400/1500");
 196 MODULE_LICENSE("GPL");
 197 MODULE_SUPPORTED_DEVICE
 198         ("watchdog");
 199 #endif /* ifdef MODULE */
 200
 201 /* Forward declarations of internal methods
 202  */
 203 #ifdef WD_DEBUG
 204 static void wd_dumpregs(void);
 205 #endif
 206 static void wd_interrupt(int irq, void *dev_id, struct pt_regs *regs);
 207 static void wd_toggleintr(struct wd_timer* pTimer, int enable);
 208 static void wd_pingtimer(struct wd_timer* pTimer);
 209 static void wd_starttimer(struct wd_timer* pTimer);
 210 static void wd_resetbrokentimer(struct wd_timer* pTimer);
 211 static void wd_stoptimer(struct wd_timer* pTimer);
 212 static void wd_brokentimer(unsigned long data);
 213 static int  wd_getstatus(struct wd_timer* pTimer);
 214
 215 /* PLD expects words to be written in LSB format,
 216  * so we must flip all words prior to writing them to regs
 217  */
 218 static inline unsigned short flip_word(unsigned short word)
 219 {
 220         return ((word & 0xff) << 8) | ((word >> 8) & 0xff);
 221 }
 222
 223 #define wd_writew(val, addr)    (writew(flip_word(val), addr))
 224 #define wd_readw(addr)                  (flip_word(readw(addr)))
 225 #define wd_writeb(val, addr)    (writeb(val, addr))
 226 #define wd_readb(addr)                  (readb(addr))
 227
 228
 229 /* CP1400s seem to have broken PLD implementations--
 230  * the interrupt_mask register cannot be written, so
 231  * no timer interrupts can be masked within the PLD.
 232  */
 233 static inline int wd_isbroken(void)
 234 {
 235         /* we could test this by read/write/read/restore
 236          * on the interrupt mask register only if OBP
 237          * 'watchdog-enable?' == FALSE, but it seems
 238          * ubiquitous on CP1400s
 239          */
 240         char val[32];
 241         prom_getproperty(prom_root_node, "model", val, sizeof(val));
 242         return((!strcmp(val, WD_BADMODEL)) ? 1 : 0);
 243 }
 244
 245 /* Retrieve watchdog-enable? option from OBP
 246  * Returns 0 if false, 1 if true
 247  */
 248 static inline int wd_opt_enable(void)
 249 {
 250         int opt_node;
 251
 252         opt_node = prom_getchild(prom_root_node);
 253         opt_node = prom_searchsiblings(opt_node, "options");
 254         return((-1 == prom_getint(opt_node, "watchdog-enable?")) ? 0 : 1);
 255 }
 256
 257 /* Retrieve watchdog-reboot? option from OBP
 258  * Returns 0 if false, 1 if true
 259  */
 260 static inline int wd_opt_reboot(void)
 261 {
 262         int opt_node;
 263
 264         opt_node = prom_getchild(prom_root_node);
 265         opt_node = prom_searchsiblings(opt_node, "options");
 266         return((-1 == prom_getint(opt_node, "watchdog-reboot?")) ? 0 : 1);
 267 }
 268
 269 /* Retrieve watchdog-timeout option from OBP
 270  * Returns OBP value, or 0 if not located
 271  */
 272 static inline int wd_opt_timeout(void)
 273 {
 274         int opt_node;
 275         char value[32];
 276         char *p = value;
 277
 278         opt_node = prom_getchild(prom_root_node);
 279         opt_node = prom_searchsiblings(opt_node, "options");
 280         opt_node = prom_getproperty(opt_node,
 281                                                                 "watchdog-timeout",
 282                                                                 value,
 283                                                                 sizeof(value));
 284         if(-1 != opt_node) {
 285                 /* atoi implementation */
 286                 for(opt_node = 0; /* nop */; p++) {
 287                         if(*p >= '0' && *p <= '9') {
 288                                 opt_node = (10*opt_node)+(*p-'0');
 289                         }
 290                         else {
 291                                 break;
 292                         }
 293                 }
 294         }
 295         return((-1 == opt_node) ? (0) : (opt_node));
 296 }
 297
 298 static int wd_open(struct inode *inode, struct file *f)
 299 {
 300         switch(MINOR(inode->i_rdev))
 301         {
 302                 case WD0_MINOR:
 303                         f->private_data = &wd_dev.watchdog[WD0_ID];
 304                         break;
 305                 case WD1_MINOR:
 306                         f->private_data = &wd_dev.watchdog[WD1_ID];
 307                         break;
 308                 case WD2_MINOR:
 309                         f->private_data = &wd_dev.watchdog[WD2_ID];
 310                         break;
 311                 default:
 312                         return(-ENODEV);
 313         }
 314
 315         /* Register IRQ on first open of device */
 316         if(0 == wd_dev.initialized)
 317         {
 318                 if (request_irq(wd_dev.irq,
 319                                                 &wd_interrupt,
 320                                                 SA_SHIRQ,
 321                                                 WD_OBPNAME,
 322                                                 (void *)wd_dev.regs)) {
 323                         printk("%s: Cannot register IRQ %s\n",
 324                                 WD_OBPNAME, __irq_itoa(wd_dev.irq));
 325                         return(-EBUSY);
 326                 }
 327                 wd_dev.initialized = 1;
 328         }
 329
 330         MOD_INC_USE_COUNT;
 331         return(0);
 332 }
 333
 334 static int wd_release(struct inode *inode, struct file *file)
 335 {
 336         MOD_DEC_USE_COUNT;
 337         return 0;
 338 }
 339
 340 static int wd_ioctl(struct inode *inode, struct file *file,
 341                      unsigned int cmd, unsigned long arg)
 342 {
 343         int     setopt                          = 0;
 344         struct  wd_timer* pTimer        = (struct wd_timer*)file->private_data;
 345         struct  watchdog_info info      = {
 346                 0,
 347                 0,
 348                 "Altera EPF8820ATC144-4"
 349         };
 350
 351         if(NULL == pTimer) {
 352                 return(-EINVAL);
 353         }
 354
 355         switch(cmd)
 356         {
 357                 /* Generic Linux IOCTLs */
 358                 case WDIOC_GETSUPPORT:
 359                         if(copy_to_user((struct watchdog_info *)arg,
 360                                                         (struct watchdog_info *)&info,
 361                                                         sizeof(struct watchdog_info))) {
 362                                 return(-EFAULT);
 363                         }
 364                         break;
 365                 case WDIOC_GETSTATUS:
 366                 case WDIOC_GETBOOTSTATUS:
 367                         if (put_user(0, (int *) arg))
 368                                 return -EFAULT;
 369                         break;
 370                 case WDIOC_KEEPALIVE:
 371                         wd_pingtimer(pTimer);
 372                         break;
 373                 case WDIOC_SETOPTIONS:
 374                         if(copy_from_user(&setopt, (void*) arg, sizeof(unsigned int))) {
 375                                 return -EFAULT;
 376                         }
 377                         if(setopt & WDIOS_DISABLECARD) {
 378                                 if(wd_dev.opt_enable) {
 379                                         printk(
 380                                                 "%s: cannot disable watchdog in ENABLED mode\n",
 381                                                 WD_OBPNAME);
 382                                         return(-EINVAL);
 383                                 }
 384                                 wd_stoptimer(pTimer);
 385                         }
 386                         else if(setopt & WDIOS_ENABLECARD) {
 387                                 wd_starttimer(pTimer);
 388                         }
 389                         else {
 390                                 return(-EINVAL);
 391                         }
 392                         break;
 393                 /* Solaris-compatible IOCTLs */
 394                 case WIOCGSTAT:
 395                         setopt = wd_getstatus(pTimer);
 396                         if(copy_to_user((void*)arg, &setopt, sizeof(unsigned int))) {
 397                                 return(-EFAULT);
 398                         }
 399                         break;
 400                 case WIOCSTART:
 401                         wd_starttimer(pTimer);
 402                         break;
 403                 case WIOCSTOP:
 404                         if(wd_dev.opt_enable) {
 405                                 printk("%s: cannot disable watchdog in ENABLED mode\n",
 406                                         WD_OBPNAME);
 407                                 return(-EINVAL);
 408                         }
 409                         wd_stoptimer(pTimer);
 410                         break;
 411                 default:
 412                         return(-EINVAL);
 413         }
 414         return(0);
 415 }
 416
 417 static ssize_t wd_write(        struct file     *file,
 418                                                         const char              *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 (ppos != &file->f_pos)
 429                 return -ESPIPE;
 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 * 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 void 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;
 462 }
 463
 464 static struct file_operations wd_fops = {
 465         owner:          THIS_MODULE,
 466         ioctl:          wd_ioctl,
 467         open:           wd_open,
 468         write:          wd_write,
 469         read:           wd_read,
 470         release:        wd_release,
 471 };
 472
 473 static struct miscdevice wd0_miscdev = { WD0_MINOR, WD0_DEVNAME, &wd_fops };
 474 static struct miscdevice wd1_miscdev = { WD1_MINOR, WD1_DEVNAME, &wd_fops };
 475 static struct miscdevice wd2_miscdev = { WD2_MINOR, WD2_DEVNAME, &wd_fops };
 476
 477 #ifdef WD_DEBUG
 478 static void wd_dumpregs(void)
 479 {
 480         /* Reading from downcounters initiates watchdog countdown--
 481          * Example is included below for illustration purposes.
 482          */
 483         int i;
 484         printk("%s: dumping register values\n", WD_OBPNAME);
 485         for(i = WD0_ID; i < WD_NUMDEVS; ++i) {
 486                         /* printk("\t%s%i: dcntr  at 0x%lx: 0x%x\n",
 487                          *      WD_OBPNAME,
 488                          *      i,
 489                          *      (unsigned long)(&wd_dev.watchdog[i].regs->dcntr),
 490                          *      readw(&wd_dev.watchdog[i].regs->dcntr));
 491                          */
 492                         printk("\t%s%i: limit  at 0x%lx: 0x%x\n",
 493                                 WD_OBPNAME,
 494                                 i,
 495                                 (unsigned long)(&wd_dev.watchdog[i].regs->limit),
 496                                 readw(&wd_dev.watchdog[i].regs->limit));
 497                         printk("\t%s%i: status at 0x%lx: 0x%x\n",
 498                                 WD_OBPNAME,
 499                                 i,
 500                                 (unsigned long)(&wd_dev.watchdog[i].regs->status),
 501                                 readb(&wd_dev.watchdog[i].regs->status));
 502                         printk("\t%s%i: driver status: 0x%x\n",
 503                                 WD_OBPNAME,
 504                                 i,
 505                                 wd_getstatus(&wd_dev.watchdog[i]));
 506         }
 507         printk("\tintr_mask  at 0x%lx: 0x%x\n",
 508                 (unsigned long)(&wd_dev.regs->pld_regs.intr_mask),
 509                 readb(&wd_dev.regs->pld_regs.intr_mask));
 510         printk("\tpld_status at 0x%lx: 0x%x\n",
 511                 (unsigned long)(&wd_dev.regs->pld_regs.status),
 512                 readb(&wd_dev.regs->pld_regs.status));
 513 }
 514 #endif
 515
 516 /* Enable or disable watchdog interrupts
 517  * Because of the CP1400 defect this should only be
 518  * called during initialzation or by wd_[start|stop]timer()
 519  *
 520  * pTimer       - pointer to timer device, or NULL to indicate all timers
 521  * enable       - non-zero to enable interrupts, zero to disable
 522  */
 523 static void wd_toggleintr(struct wd_timer* pTimer, int enable)
 524 {
 525         unsigned char curregs = wd_readb(&wd_dev.regs->pld_regs.intr_mask);
 526         unsigned char setregs =
 527                 (NULL == pTimer) ?
 528                         (WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) :
 529                         (pTimer->intr_mask);
 530
 531         (WD_INTR_ON == enable) ?
 532                 (curregs &= ~setregs):
 533                 (curregs |=  setregs);
 534
 535         wd_writeb(curregs, &wd_dev.regs->pld_regs.intr_mask);
 536         return;
 537 }
 538
 539 /* Reset countdown timer with 'limit' value and continue countdown.
 540  * This will not start a stopped timer.
 541  *
 542  * pTimer       - pointer to timer device
 543  */
 544 static void wd_pingtimer(struct wd_timer* pTimer)
 545 {
 546         if(wd_readb(&pTimer->regs->status) & WD_S_RUNNING) {
 547                 wd_readb(&pTimer->regs->dcntr);
 548         }
 549 }
 550
 551 /* Stop a running watchdog timer-- the timer actually keeps
 552  * running, but the interrupt is masked so that no action is
 553  * taken upon expiration.
 554  *
 555  * pTimer       - pointer to timer device
 556  */
 557 static void wd_stoptimer(struct wd_timer* pTimer)
 558 {
 559         if(wd_readb(&pTimer->regs->status) & WD_S_RUNNING) {
 560                 wd_toggleintr(pTimer, WD_INTR_OFF);
 561
 562                 if(wd_dev.isbaddoggie) {
 563                         pTimer->runstatus |= WD_STAT_BSTOP;
 564                         wd_brokentimer((unsigned long)&wd_dev);
 565                 }
 566         }
 567 }
 568
 569 /* Start a watchdog timer with the specified limit value
 570  * If the watchdog is running, it will be restarted with
 571  * the provided limit value.
 572  *
 573  * This function will enable interrupts on the specified
 574  * watchdog.
 575  *
 576  * pTimer       - pointer to timer device
 577  * limit        - limit (countdown) value in 1/10th seconds
 578  */
 579 static void wd_starttimer(struct wd_timer* pTimer)
 580 {
 581         if(wd_dev.isbaddoggie) {
 582                 pTimer->runstatus &= ~WD_STAT_BSTOP;
 583         }
 584         pTimer->runstatus &= ~WD_STAT_SVCD;
 585
 586         wd_writew(pTimer->timeout, &pTimer->regs->limit);
 587         wd_toggleintr(pTimer, WD_INTR_ON);
 588 }
 589
 590 /* Restarts timer with maximum limit value and
 591  * does not unset 'brokenstop' value.
 592  */
 593 static void wd_resetbrokentimer(struct wd_timer* pTimer)
 594 {
 595         wd_toggleintr(pTimer, WD_INTR_ON);
 596         wd_writew(WD_BLIMIT, &pTimer->regs->limit);
 597 }
 598
 599 /* Timer device initialization helper.
 600  * Returns 0 on success, other on failure
 601  */
 602 static int wd_inittimer(int whichdog)
 603 {
 604         struct miscdevice                               *whichmisc;
 605         volatile struct wd_timer_regblk *whichregs;
 606         char                                                    whichident[8];
 607         int                                                             whichmask;
 608         __u16                                                   whichlimit;
 609
 610         switch(whichdog)
 611         {
 612                 case WD0_ID:
 613                         whichmisc = &wd0_miscdev;
 614                         strcpy(whichident, "RIC");
 615                         whichregs = &wd_dev.regs->wd0_regs;
 616                         whichmask = WD0_INTR_MASK;
 617                         whichlimit= (0 == wd0_timeout)  ?
 618                                                 (wd_dev.opt_timeout):
 619                                                 (wd0_timeout);
 620                         break;
 621                 case WD1_ID:
 622                         whichmisc = &wd1_miscdev;
 623                         strcpy(whichident, "XIR");
 624                         whichregs = &wd_dev.regs->wd1_regs;
 625                         whichmask = WD1_INTR_MASK;
 626                         whichlimit= (0 == wd1_timeout)  ?
 627                                                 (wd_dev.opt_timeout):
 628                                                 (wd1_timeout);
 629                         break;
 630                 case WD2_ID:
 631                         whichmisc = &wd2_miscdev;
 632                         strcpy(whichident, "POR");
 633                         whichregs = &wd_dev.regs->wd2_regs;
 634                         whichmask = WD2_INTR_MASK;
 635                         whichlimit= (0 == wd2_timeout)  ?
 636                                                 (wd_dev.opt_timeout):
 637                                                 (wd2_timeout);
 638                         break;
 639                 default:
 640                         printk("%s: %s: invalid watchdog id: %i\n",
 641                                 WD_OBPNAME, __FUNCTION__, whichdog);
 642                         return(1);
 643         }
 644         if(0 != misc_register(whichmisc))
 645         {
 646                 return(1);
 647         }
 648         wd_dev.watchdog[whichdog].regs                  = whichregs;
 649         wd_dev.watchdog[whichdog].timeout               = whichlimit;
 650         wd_dev.watchdog[whichdog].intr_mask             = whichmask;
 651         wd_dev.watchdog[whichdog].runstatus     &= ~WD_STAT_BSTOP;
 652         wd_dev.watchdog[whichdog].runstatus     |= WD_STAT_INIT;
 653
 654         printk("%s%i: %s hardware watchdog [%01i.%i sec] %s\n",
 655                 WD_OBPNAME,
 656                 whichdog,
 657                 whichident,
 658                 wd_dev.watchdog[whichdog].timeout / 10,
 659                 wd_dev.watchdog[whichdog].timeout % 10,
 660                 (0 != wd_dev.opt_enable) ? "in ENABLED mode" : "");
 661         return(0);
 662 }
 663
 664 /* Timer method called to reset stopped watchdogs--
 665  * because of the PLD bug on CP1400, we cannot mask
 666  * interrupts within the PLD so me must continually
 667  * reset the timers ad infinitum.
 668  */
 669 static void wd_brokentimer(unsigned long data)
 670 {
 671         struct wd_device* pDev = (struct wd_device*)data;
 672         int id, tripped = 0;
 673
 674         /* kill a running timer instance, in case we
 675          * were called directly instead of by kernel timer
 676          */
 677         if(timer_pending(&wd_timer)) {
 678                 del_timer(&wd_timer);
 679         }
 680
 681         for(id = WD0_ID; id < WD_NUMDEVS; ++id) {
 682                 if(pDev->watchdog[id].runstatus & WD_STAT_BSTOP) {
 683                         ++tripped;
 684                         wd_resetbrokentimer(&pDev->watchdog[id]);
 685                 }
 686         }
 687
 688         if(tripped) {
 689                 /* there is at least one timer brokenstopped-- reschedule */
 690                 wd_timer.expires = WD_BTIMEOUT;
 691                 add_timer(&wd_timer);
 692         }
 693 }
 694
 695 static int wd_getstatus(struct wd_timer* pTimer)
 696 {
 697         unsigned char stat = wd_readb(&pTimer->regs->status);
 698         unsigned char intr = wd_readb(&wd_dev.regs->pld_regs.intr_mask);
 699         unsigned char ret  = WD_STOPPED;
 700
 701         /* determine STOPPED */
 702         if(0 == stat ) {
 703                 return(ret);
 704         }
 705         /* determine EXPIRED vs FREERUN vs RUNNING */
 706         else if(WD_S_EXPIRED & stat) {
 707                 ret = WD_EXPIRED;
 708         }
 709         else if(WD_S_RUNNING & stat) {
 710                 if(intr & pTimer->intr_mask) {
 711                         ret = WD_FREERUN;
 712                 }
 713                 else {
 714                         /* Fudge WD_EXPIRED status for defective CP1400--
 715                          * IF timer is running
 716                          *      AND brokenstop is set
 717                          *      AND an interrupt has been serviced
 718                          * we are WD_EXPIRED.
 719                          *
 720                          * IF timer is running
 721                          *      AND brokenstop is set
 722                          *      AND no interrupt has been serviced
 723                          * we are WD_FREERUN.
 724                          */
 725                         if(wd_dev.isbaddoggie && (pTimer->runstatus & WD_STAT_BSTOP)) {
 726                                 if(pTimer->runstatus & WD_STAT_SVCD) {
 727                                         ret = WD_EXPIRED;
 728                                 }
 729                                 else {
 730                                         /* we could as well pretend we are expired */
 731                                         ret = WD_FREERUN;
 732                                 }
 733                         }
 734                         else {
 735                                 ret = WD_RUNNING;
 736                         }
 737                 }
 738         }
 739
 740         /* determine SERVICED */
 741         if(pTimer->runstatus & WD_STAT_SVCD) {
 742                 ret |= WD_SERVICED;
 743         }
 744
 745         return(ret);
 746 }
 747
 748 static int __init wd_init(void)
 749 {
 750         int     id;
 751         struct  linux_ebus *ebus = NULL;
 752         struct  linux_ebus_device *edev = NULL;
 753
 754         for_each_ebus(ebus) {
 755                 for_each_ebusdev(edev, ebus) {
 756                         if (!strcmp(edev->prom_name, WD_OBPNAME))
 757                                 goto ebus_done;
 758                 }
 759         }
 760
 761 ebus_done:
 762         if(!edev) {
 763                 printk("%s: unable to locate device\n", WD_OBPNAME);
 764                 return -ENODEV;
 765         }
 766
 767         wd_dev.regs =
 768                 ioremap(edev->resource[0].start, sizeof(struct wd_regblk));
 769
 770         if(NULL == wd_dev.regs) {
 771                 printk("%s: unable to map registers\n", WD_OBPNAME);
 772                 return(-ENODEV);
 773         }
 774
 775         /* initialize device structure from OBP parameters */
 776         wd_dev.irq                      = edev->irqs[0];
 777         wd_dev.opt_enable       = wd_opt_enable();
 778         wd_dev.opt_reboot       = wd_opt_reboot();
 779         wd_dev.opt_timeout      = wd_opt_timeout();
 780         wd_dev.isbaddoggie      = wd_isbroken();
 781
 782         /* disable all interrupts unless watchdog-enabled? == true */
 783         if(! wd_dev.opt_enable) {
 784                 wd_toggleintr(NULL, WD_INTR_OFF);
 785         }
 786
 787         /* register miscellaneous devices */
 788         for(id = WD0_ID; id < WD_NUMDEVS; ++id) {
 789                 if(0 != wd_inittimer(id)) {
 790                         printk("%s%i: unable to initialize\n", WD_OBPNAME, id);
 791                 }
 792         }
 793
 794         /* warn about possible defective PLD */
 795         if(wd_dev.isbaddoggie) {
 796                 init_timer(&wd_timer);
 797                 wd_timer.function       = wd_brokentimer;
 798                 wd_timer.data           = (unsigned long)&wd_dev;
 799                 wd_timer.expires        = WD_BTIMEOUT;
 800
 801                 printk("%s: PLD defect workaround enabled for model %s\n",
 802                         WD_OBPNAME, WD_BADMODEL);
 803         }
 804         return(0);
 805 }
 806
 807 static void __exit wd_cleanup(void)
 808 {
 809         int id;
 810
 811         /* if 'watchdog-enable?' == TRUE, timers are not stopped
 812          * when module is unloaded.  All brokenstopped timers will
 813          * also now eventually trip.
 814          */
 815         for(id = WD0_ID; id < WD_NUMDEVS; ++id) {
 816                 if(WD_S_RUNNING == wd_readb(&wd_dev.watchdog[id].regs->status)) {
 817                         if(wd_dev.opt_enable) {
 818                                 printk(KERN_WARNING "%s%i: timer not stopped at release\n",
 819                                         WD_OBPNAME, id);
 820                         }
 821                         else {
 822                                 wd_stoptimer(&wd_dev.watchdog[id]);
 823                                 if(wd_dev.watchdog[id].runstatus & WD_STAT_BSTOP) {
 824                                         wd_resetbrokentimer(&wd_dev.watchdog[id]);
 825                                         printk(KERN_WARNING
 826                                                         "%s%i: defect workaround disabled at release, "\
 827                                                         "timer expires in ~%01i sec\n",
 828                                                         WD_OBPNAME, id,
 829                                                         wd_readw(&wd_dev.watchdog[id].regs->limit) / 10);
 830                                 }
 831                         }
 832                 }
 833         }
 834
 835         if(wd_dev.isbaddoggie && timer_pending(&wd_timer)) {
 836                 del_timer(&wd_timer);
 837         }
 838         if(0 != (wd_dev.watchdog[WD0_ID].runstatus & WD_STAT_INIT)) {
 839                 misc_deregister(&wd0_miscdev);
 840         }
 841         if(0 != (wd_dev.watchdog[WD1_ID].runstatus & WD_STAT_INIT)) {
 842                 misc_deregister(&wd1_miscdev);
 843         }
 844         if(0 != (wd_dev.watchdog[WD2_ID].runstatus & WD_STAT_INIT)) {
 845                 misc_deregister(&wd2_miscdev);
 846         }
 847         if(0 != wd_dev.initialized) {
 848                 free_irq(wd_dev.irq, (void *)wd_dev.regs);
 849         }
 850         iounmap(wd_dev.regs);
 851 }
 852
 853 module_init(wd_init);
 854 module_exit(wd_cleanup);