Merge branch 'for-linus' of master.kernel.org:/pub/scm/linux/kernel/git/jmorris/selin...
[linux-2.6] / 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);