Linux-2.6.12-rc2
[linux-2.6.git] / drivers / sbus / char / cpwatchdog.c
1 /* cpwatchdog.c - driver implementation for hardware watchdog
2  * timers found on Sun Microsystems CP1400 and CP1500 boards.
3  *
4  * This device supports both the generic Linux watchdog 
5  * interface and Solaris-compatible ioctls as best it is
6  * able.
7  *
8  * NOTE:        CP1400 systems appear to have a defective intr_mask
9  *                      register on the PLD, preventing the disabling of
10  *                      timer interrupts.  We use a timer to periodically 
11  *                      reset 'stopped' watchdogs on affected platforms.
12  *
13  * TODO:        DevFS support (/dev/watchdogs/0 ... /dev/watchdogs/2)
14  *
15  * Copyright (c) 2000 Eric Brower (ebrower@usa.net)
16  */
17
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/fs.h>
21 #include <linux/errno.h>
22 #include <linux/major.h>
23 #include <linux/init.h>
24 #include <linux/miscdevice.h>
25 #include <linux/sched.h>
26 #include <linux/interrupt.h>
27 #include <linux/ioport.h>
28 #include <linux/timer.h>
29 #include <asm/irq.h>
30 #include <asm/ebus.h>
31 #include <asm/oplib.h>
32 #include <asm/uaccess.h>
33
34 #include <asm/watchdog.h>
35
36 #define WD_OBPNAME      "watchdog"
37 #define WD_BADMODEL "SUNW,501-5336"
38 #define WD_BTIMEOUT     (jiffies + (HZ * 1000))
39 #define WD_BLIMIT       0xFFFF
40
41 #define WD0_DEVNAME "watchdog0"
42 #define WD1_DEVNAME "watchdog1"
43 #define WD2_DEVNAME "watchdog2"
44
45 #define WD0_MINOR       212
46 #define WD1_MINOR       213     
47 #define WD2_MINOR       214     
48
49
50 /* Internal driver definitions
51  */
52 #define WD0_ID                  0               /* Watchdog0                                            */
53 #define WD1_ID                  1               /* Watchdog1                                            */
54 #define WD2_ID                  2               /* Watchdog2                                            */
55 #define WD_NUMDEVS              3               /* Device contains 3 timers                     */
56
57 #define WD_INTR_OFF             0               /* Interrupt disable value                      */
58 #define WD_INTR_ON              1               /* Interrupt enable value                       */
59
60 #define WD_STAT_INIT    0x01    /* Watchdog timer is initialized        */
61 #define WD_STAT_BSTOP   0x02    /* Watchdog timer is brokenstopped      */
62 #define WD_STAT_SVCD    0x04    /* Watchdog interrupt occurred          */
63
64 /* Register value definitions
65  */
66 #define WD0_INTR_MASK   0x01    /* Watchdog device interrupt masks      */
67 #define WD1_INTR_MASK   0x02
68 #define WD2_INTR_MASK   0x04
69
70 #define WD_S_RUNNING    0x01    /* Watchdog device status running       */
71 #define WD_S_EXPIRED    0x02    /* Watchdog device status expired       */
72
73 /* Sun uses Altera PLD EPF8820ATC144-4 
74  * providing three hardware watchdogs:
75  *
76  *      1) RIC - sends an interrupt when triggered
77  *      2) XIR - asserts XIR_B_RESET when triggered, resets CPU
78  *      3) POR - asserts POR_B_RESET when triggered, resets CPU, backplane, board
79  *
80  *** Timer register block definition (struct wd_timer_regblk)
81  *
82  * dcntr and limit registers (halfword access):      
83  * -------------------
84  * | 15 | ...| 1 | 0 |
85  * -------------------
86  * |-  counter val  -|
87  * -------------------
88  * dcntr -      Current 16-bit downcounter value.
89  *                      When downcounter reaches '0' watchdog expires.
90  *                      Reading this register resets downcounter with 'limit' value.
91  * limit -      16-bit countdown value in 1/10th second increments.
92  *                      Writing this register begins countdown with input value.
93  *                      Reading from this register does not affect counter.
94  * NOTES:       After watchdog reset, dcntr and limit contain '1'
95  *
96  * status register (byte access):
97  * ---------------------------
98  * | 7 | ... | 2 |  1  |  0  |
99  * --------------+------------
100  * |-   UNUSED  -| EXP | RUN |
101  * ---------------------------
102  * status-      Bit 0 - Watchdog is running
103  *                      Bit 1 - Watchdog has expired
104  *
105  *** PLD register block definition (struct wd_pld_regblk)
106  *
107  * intr_mask register (byte access):
108  * ---------------------------------
109  * | 7 | ... | 3 |  2  |  1  |  0  |
110  * +-------------+------------------
111  * |-   UNUSED  -| WD3 | WD2 | WD1 |
112  * ---------------------------------
113  * WD3 -  1 == Interrupt disabled for watchdog 3
114  * WD2 -  1 == Interrupt disabled for watchdog 2
115  * WD1 -  1 == Interrupt disabled for watchdog 1
116  *
117  * pld_status register (byte access):
118  * UNKNOWN, MAGICAL MYSTERY REGISTER
119  *
120  */
121 #define WD_TIMER_REGSZ  16
122 #define WD0_OFF         0
123 #define WD1_OFF         (WD_TIMER_REGSZ * 1)
124 #define WD2_OFF         (WD_TIMER_REGSZ * 2)
125 #define PLD_OFF         (WD_TIMER_REGSZ * 3)
126
127 #define WD_DCNTR        0x00
128 #define WD_LIMIT        0x04
129 #define WD_STATUS       0x08
130
131 #define PLD_IMASK       (PLD_OFF + 0x00)
132 #define PLD_STATUS      (PLD_OFF + 0x04)
133
134 /* Individual timer structure 
135  */
136 struct wd_timer {
137         __u16                   timeout;
138         __u8                    intr_mask;
139         unsigned char           runstatus;
140         void __iomem            *regs;
141 };
142
143 /* Device structure
144  */
145 struct wd_device {
146         int                             irq;
147         spinlock_t              lock;
148         unsigned char   isbaddoggie;    /* defective PLD */
149         unsigned char   opt_enable;
150         unsigned char   opt_reboot;
151         unsigned short  opt_timeout;
152         unsigned char   initialized;
153         struct wd_timer watchdog[WD_NUMDEVS];
154         void __iomem    *regs;
155 };
156
157 static struct wd_device wd_dev = { 
158                 0, SPIN_LOCK_UNLOCKED, 0, 0, 0, 0,
159 };
160
161 static struct timer_list wd_timer;
162
163 static int wd0_timeout = 0;
164 static int wd1_timeout = 0;
165 static int wd2_timeout = 0;
166
167 #ifdef MODULE
168 module_param    (wd0_timeout, int, 0);
169 MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs");
170 module_param    (wd1_timeout, int, 0);
171 MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs");
172 module_param    (wd2_timeout, int, 0);
173 MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs");
174
175 MODULE_AUTHOR
176         ("Eric Brower <ebrower@usa.net>");
177 MODULE_DESCRIPTION
178         ("Hardware watchdog driver for Sun Microsystems CP1400/1500");
179 MODULE_LICENSE("GPL");
180 MODULE_SUPPORTED_DEVICE
181         ("watchdog");
182 #endif /* ifdef MODULE */
183
184 /* Forward declarations of internal methods
185  */
186 #ifdef WD_DEBUG
187 static void wd_dumpregs(void);
188 #endif
189 static irqreturn_t wd_interrupt(int irq, void *dev_id, struct pt_regs *regs);
190 static void wd_toggleintr(struct wd_timer* pTimer, int enable);
191 static void wd_pingtimer(struct wd_timer* pTimer);
192 static void wd_starttimer(struct wd_timer* pTimer);
193 static void wd_resetbrokentimer(struct wd_timer* pTimer);
194 static void wd_stoptimer(struct wd_timer* pTimer);
195 static void wd_brokentimer(unsigned long data);
196 static int  wd_getstatus(struct wd_timer* pTimer);
197
198 /* PLD expects words to be written in LSB format,
199  * so we must flip all words prior to writing them to regs
200  */
201 static inline unsigned short flip_word(unsigned short word)
202 {
203         return ((word & 0xff) << 8) | ((word >> 8) & 0xff);
204 }
205
206 #define wd_writew(val, addr)    (writew(flip_word(val), addr))
207 #define wd_readw(addr)                  (flip_word(readw(addr)))
208 #define wd_writeb(val, addr)    (writeb(val, addr))
209 #define wd_readb(addr)                  (readb(addr))
210
211
212 /* CP1400s seem to have broken PLD implementations--
213  * the interrupt_mask register cannot be written, so
214  * no timer interrupts can be masked within the PLD.
215  */
216 static inline int wd_isbroken(void)
217 {
218         /* we could test this by read/write/read/restore
219          * on the interrupt mask register only if OBP
220          * 'watchdog-enable?' == FALSE, but it seems 
221          * ubiquitous on CP1400s
222          */
223         char val[32];
224         prom_getproperty(prom_root_node, "model", val, sizeof(val));
225         return((!strcmp(val, WD_BADMODEL)) ? 1 : 0);
226 }
227                 
228 /* Retrieve watchdog-enable? option from OBP
229  * Returns 0 if false, 1 if true
230  */
231 static inline int wd_opt_enable(void)
232 {
233         int opt_node;
234
235         opt_node = prom_getchild(prom_root_node);
236         opt_node = prom_searchsiblings(opt_node, "options");
237         return((-1 == prom_getint(opt_node, "watchdog-enable?")) ? 0 : 1);
238 }
239
240 /* Retrieve watchdog-reboot? option from OBP
241  * Returns 0 if false, 1 if true
242  */
243 static inline int wd_opt_reboot(void)
244 {
245         int opt_node;
246
247         opt_node = prom_getchild(prom_root_node);
248         opt_node = prom_searchsiblings(opt_node, "options");
249         return((-1 == prom_getint(opt_node, "watchdog-reboot?")) ? 0 : 1);
250 }
251
252 /* Retrieve watchdog-timeout option from OBP
253  * Returns OBP value, or 0 if not located
254  */
255 static inline int wd_opt_timeout(void)
256 {
257         int opt_node;
258         char value[32];
259         char *p = value;
260
261         opt_node = prom_getchild(prom_root_node);
262         opt_node = prom_searchsiblings(opt_node, "options");
263         opt_node = prom_getproperty(opt_node, 
264                                                                 "watchdog-timeout", 
265                                                                 value, 
266                                                                 sizeof(value));
267         if(-1 != opt_node) {
268                 /* atoi implementation */
269                 for(opt_node = 0; /* nop */; p++) {
270                         if(*p >= '0' && *p <= '9') {
271                                 opt_node = (10*opt_node)+(*p-'0');
272                         }
273                         else {
274                                 break;
275                         }
276                 }
277         }
278         return((-1 == opt_node) ? (0) : (opt_node)); 
279 }
280
281 static int wd_open(struct inode *inode, struct file *f)
282 {
283         switch(iminor(inode))
284         {
285                 case WD0_MINOR:
286                         f->private_data = &wd_dev.watchdog[WD0_ID];
287                         break;
288                 case WD1_MINOR:
289                         f->private_data = &wd_dev.watchdog[WD1_ID];
290                         break;
291                 case WD2_MINOR:
292                         f->private_data = &wd_dev.watchdog[WD2_ID];
293                         break;
294                 default:
295                         return(-ENODEV);
296         }
297
298         /* Register IRQ on first open of device */
299         if(0 == wd_dev.initialized)
300         {       
301                 if (request_irq(wd_dev.irq, 
302                                                 &wd_interrupt, 
303                                                 SA_SHIRQ,
304                                                 WD_OBPNAME,
305                                                 (void *)wd_dev.regs)) {
306                         printk("%s: Cannot register IRQ %s\n", 
307                                 WD_OBPNAME, __irq_itoa(wd_dev.irq));
308                         return(-EBUSY);
309                 }
310                 wd_dev.initialized = 1;
311         }
312
313         return(nonseekable_open(inode, f));
314 }
315
316 static int wd_release(struct inode *inode, struct file *file)
317 {
318         return 0;
319 }
320
321 static int wd_ioctl(struct inode *inode, struct file *file, 
322                      unsigned int cmd, unsigned long arg)
323 {
324         int     setopt                          = 0;
325         struct  wd_timer* pTimer        = (struct wd_timer*)file->private_data;
326         void __user *argp = (void __user *)arg;
327         struct  watchdog_info info      = {
328                 0,
329                 0,
330                 "Altera EPF8820ATC144-4"
331         };
332
333         if(NULL == pTimer) {
334                 return(-EINVAL);
335         }
336
337         switch(cmd)
338         {
339                 /* Generic Linux IOCTLs */
340                 case WDIOC_GETSUPPORT:
341                         if(copy_to_user(argp, &info, sizeof(struct watchdog_info))) {
342                                 return(-EFAULT);
343                         }
344                         break;
345                 case WDIOC_GETSTATUS:
346                 case WDIOC_GETBOOTSTATUS:
347                         if (put_user(0, (int __user *)argp))
348                                 return -EFAULT;
349                         break;
350                 case WDIOC_KEEPALIVE:
351                         wd_pingtimer(pTimer);
352                         break;
353                 case WDIOC_SETOPTIONS:
354                         if(copy_from_user(&setopt, argp, sizeof(unsigned int))) {
355                                 return -EFAULT;
356                         }
357                         if(setopt & WDIOS_DISABLECARD) {
358                                 if(wd_dev.opt_enable) {
359                                         printk(
360                                                 "%s: cannot disable watchdog in ENABLED mode\n",
361                                                 WD_OBPNAME);
362                                         return(-EINVAL);
363                                 }
364                                 wd_stoptimer(pTimer);
365                         }
366                         else if(setopt & WDIOS_ENABLECARD) {
367                                 wd_starttimer(pTimer);
368                         }
369                         else {
370                                 return(-EINVAL);
371                         }       
372                         break;
373                 /* Solaris-compatible IOCTLs */
374                 case WIOCGSTAT:
375                         setopt = wd_getstatus(pTimer);
376                         if(copy_to_user(argp, &setopt, sizeof(unsigned int))) {
377                                 return(-EFAULT);
378                         }
379                         break;
380                 case WIOCSTART:
381                         wd_starttimer(pTimer);
382                         break;
383                 case WIOCSTOP:
384                         if(wd_dev.opt_enable) {
385                                 printk("%s: cannot disable watchdog in ENABLED mode\n",
386                                         WD_OBPNAME);
387                                 return(-EINVAL);
388                         }
389                         wd_stoptimer(pTimer);
390                         break;
391                 default:
392                         return(-EINVAL);
393         }
394         return(0);
395 }
396
397 static ssize_t wd_write(struct file     *file, 
398                         const char      __user *buf, 
399                         size_t          count, 
400                         loff_t          *ppos)
401 {
402         struct wd_timer* pTimer = (struct wd_timer*)file->private_data;
403
404         if(NULL == pTimer) {
405                 return(-EINVAL);
406         }
407
408         if (count) {
409                 wd_pingtimer(pTimer);
410                 return 1;
411         }
412         return 0;
413 }
414
415 static ssize_t wd_read(struct file * file, char __user *buffer,
416                         size_t count, loff_t *ppos)
417 {
418 #ifdef WD_DEBUG
419         wd_dumpregs();
420         return(0);
421 #else
422         return(-EINVAL);
423 #endif /* ifdef WD_DEBUG */
424 }
425
426 static irqreturn_t wd_interrupt(int irq, void *dev_id, struct pt_regs *regs)
427 {
428         /* Only WD0 will interrupt-- others are NMI and we won't
429          * see them here....
430          */
431         spin_lock_irq(&wd_dev.lock);
432         if((unsigned long)wd_dev.regs == (unsigned long)dev_id)
433         {
434                 wd_stoptimer(&wd_dev.watchdog[WD0_ID]);
435                 wd_dev.watchdog[WD0_ID].runstatus |=  WD_STAT_SVCD;
436         }
437         spin_unlock_irq(&wd_dev.lock);
438         return IRQ_HANDLED;
439 }
440
441 static struct file_operations wd_fops = {
442         .owner =        THIS_MODULE,
443         .ioctl =        wd_ioctl,
444         .open =         wd_open,
445         .write =        wd_write,
446         .read =         wd_read,
447         .release =      wd_release,
448 };
449
450 static struct miscdevice wd0_miscdev = { WD0_MINOR, WD0_DEVNAME, &wd_fops };
451 static struct miscdevice wd1_miscdev = { WD1_MINOR, WD1_DEVNAME, &wd_fops };
452 static struct miscdevice wd2_miscdev = { WD2_MINOR, WD2_DEVNAME, &wd_fops };
453
454 #ifdef WD_DEBUG
455 static void wd_dumpregs(void)
456 {
457         /* Reading from downcounters initiates watchdog countdown--
458          * Example is included below for illustration purposes.
459          */
460         int i;
461         printk("%s: dumping register values\n", WD_OBPNAME);
462         for(i = WD0_ID; i < WD_NUMDEVS; ++i) {
463                         /* printk("\t%s%i: dcntr  at 0x%lx: 0x%x\n", 
464                          *      WD_OBPNAME,
465                          *      i,
466                          *      (unsigned long)(&wd_dev.watchdog[i].regs->dcntr), 
467                          *      readw(&wd_dev.watchdog[i].regs->dcntr));
468                          */
469                         printk("\t%s%i: limit  at 0x%lx: 0x%x\n", 
470                                 WD_OBPNAME,
471                                 i,
472                                 (unsigned long)(&wd_dev.watchdog[i].regs->limit), 
473                                 readw(&wd_dev.watchdog[i].regs->limit));
474                         printk("\t%s%i: status at 0x%lx: 0x%x\n", 
475                                 WD_OBPNAME,
476                                 i,
477                                 (unsigned long)(&wd_dev.watchdog[i].regs->status), 
478                                 readb(&wd_dev.watchdog[i].regs->status));
479                         printk("\t%s%i: driver status: 0x%x\n",
480                                 WD_OBPNAME,
481                                 i,
482                                 wd_getstatus(&wd_dev.watchdog[i]));
483         }
484         printk("\tintr_mask  at %p: 0x%x\n", 
485                 wd_dev.regs + PLD_IMASK,
486                 readb(wd_dev.regs + PLD_IMASK));
487         printk("\tpld_status at %p: 0x%x\n", 
488                 wd_dev.regs + PLD_STATUS, 
489                 readb(wd_dev.regs + PLD_STATUS));
490 }
491 #endif
492
493 /* Enable or disable watchdog interrupts
494  * Because of the CP1400 defect this should only be
495  * called during initialzation or by wd_[start|stop]timer()
496  *
497  * pTimer       - pointer to timer device, or NULL to indicate all timers 
498  * enable       - non-zero to enable interrupts, zero to disable
499  */
500 static void wd_toggleintr(struct wd_timer* pTimer, int enable)
501 {
502         unsigned char curregs = wd_readb(wd_dev.regs + PLD_IMASK);
503         unsigned char setregs = 
504                 (NULL == pTimer) ? 
505                         (WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) : 
506                         (pTimer->intr_mask);
507
508         (WD_INTR_ON == enable) ?
509                 (curregs &= ~setregs):
510                 (curregs |=  setregs);
511
512         wd_writeb(curregs, wd_dev.regs + PLD_IMASK);
513         return;
514 }
515
516 /* Reset countdown timer with 'limit' value and continue countdown.
517  * This will not start a stopped timer.
518  *
519  * pTimer       - pointer to timer device
520  */
521 static void wd_pingtimer(struct wd_timer* pTimer)
522 {
523         if (wd_readb(pTimer->regs + WD_STATUS) & WD_S_RUNNING) {
524                 wd_readw(pTimer->regs + WD_DCNTR);
525         }
526 }
527
528 /* Stop a running watchdog timer-- the timer actually keeps
529  * running, but the interrupt is masked so that no action is
530  * taken upon expiration.
531  *
532  * pTimer       - pointer to timer device
533  */
534 static void wd_stoptimer(struct wd_timer* pTimer)
535 {
536         if(wd_readb(pTimer->regs + WD_STATUS) & WD_S_RUNNING) {
537                 wd_toggleintr(pTimer, WD_INTR_OFF);
538
539                 if(wd_dev.isbaddoggie) {
540                         pTimer->runstatus |= WD_STAT_BSTOP;
541                         wd_brokentimer((unsigned long)&wd_dev);
542                 }
543         }
544 }
545
546 /* Start a watchdog timer with the specified limit value
547  * If the watchdog is running, it will be restarted with
548  * the provided limit value.
549  *
550  * This function will enable interrupts on the specified
551  * watchdog.
552  *
553  * pTimer       - pointer to timer device
554  * limit        - limit (countdown) value in 1/10th seconds
555  */
556 static void wd_starttimer(struct wd_timer* pTimer)
557 {
558         if(wd_dev.isbaddoggie) {
559                 pTimer->runstatus &= ~WD_STAT_BSTOP;
560         }
561         pTimer->runstatus &= ~WD_STAT_SVCD;
562
563         wd_writew(pTimer->timeout, pTimer->regs + WD_LIMIT);
564         wd_toggleintr(pTimer, WD_INTR_ON);
565 }
566
567 /* Restarts timer with maximum limit value and
568  * does not unset 'brokenstop' value.
569  */
570 static void wd_resetbrokentimer(struct wd_timer* pTimer)
571 {
572         wd_toggleintr(pTimer, WD_INTR_ON);
573         wd_writew(WD_BLIMIT, pTimer->regs + WD_LIMIT);
574 }
575
576 /* Timer device initialization helper.
577  * Returns 0 on success, other on failure
578  */
579 static int wd_inittimer(int whichdog)
580 {
581         struct miscdevice                               *whichmisc;
582         void __iomem *whichregs;
583         char                                                    whichident[8];
584         int                                                             whichmask;
585         __u16                                                   whichlimit;
586
587         switch(whichdog)
588         {
589                 case WD0_ID:
590                         whichmisc = &wd0_miscdev;
591                         strcpy(whichident, "RIC");
592                         whichregs = wd_dev.regs + WD0_OFF;
593                         whichmask = WD0_INTR_MASK;
594                         whichlimit= (0 == wd0_timeout)  ? 
595                                                 (wd_dev.opt_timeout): 
596                                                 (wd0_timeout);
597                         break;
598                 case WD1_ID:
599                         whichmisc = &wd1_miscdev;
600                         strcpy(whichident, "XIR");
601                         whichregs = wd_dev.regs + WD1_OFF;
602                         whichmask = WD1_INTR_MASK;
603                         whichlimit= (0 == wd1_timeout)  ? 
604                                                 (wd_dev.opt_timeout): 
605                                                 (wd1_timeout);
606                         break;
607                 case WD2_ID:
608                         whichmisc = &wd2_miscdev;
609                         strcpy(whichident, "POR");
610                         whichregs = wd_dev.regs + WD2_OFF;
611                         whichmask = WD2_INTR_MASK;
612                         whichlimit= (0 == wd2_timeout)  ? 
613                                                 (wd_dev.opt_timeout): 
614                                                 (wd2_timeout);
615                         break;
616                 default:
617                         printk("%s: %s: invalid watchdog id: %i\n",
618                                 WD_OBPNAME, __FUNCTION__, whichdog);
619                         return(1);
620         }
621         if(0 != misc_register(whichmisc))
622         {
623                 return(1);
624         }
625         wd_dev.watchdog[whichdog].regs                  = whichregs;
626         wd_dev.watchdog[whichdog].timeout               = whichlimit;
627         wd_dev.watchdog[whichdog].intr_mask             = whichmask;
628         wd_dev.watchdog[whichdog].runstatus     &= ~WD_STAT_BSTOP;
629         wd_dev.watchdog[whichdog].runstatus     |= WD_STAT_INIT;
630
631         printk("%s%i: %s hardware watchdog [%01i.%i sec] %s\n", 
632                 WD_OBPNAME, 
633                 whichdog, 
634                 whichident, 
635                 wd_dev.watchdog[whichdog].timeout / 10,
636                 wd_dev.watchdog[whichdog].timeout % 10,
637                 (0 != wd_dev.opt_enable) ? "in ENABLED mode" : "");
638         return(0);
639 }
640
641 /* Timer method called to reset stopped watchdogs--
642  * because of the PLD bug on CP1400, we cannot mask
643  * interrupts within the PLD so me must continually
644  * reset the timers ad infinitum.
645  */
646 static void wd_brokentimer(unsigned long data)
647 {
648         struct wd_device* pDev = (struct wd_device*)data;
649         int id, tripped = 0;
650
651         /* kill a running timer instance, in case we
652          * were called directly instead of by kernel timer
653          */
654         if(timer_pending(&wd_timer)) {
655                 del_timer(&wd_timer);
656         }
657
658         for(id = WD0_ID; id < WD_NUMDEVS; ++id) {
659                 if(pDev->watchdog[id].runstatus & WD_STAT_BSTOP) {
660                         ++tripped;
661                         wd_resetbrokentimer(&pDev->watchdog[id]);
662                 }
663         }
664
665         if(tripped) {
666                 /* there is at least one timer brokenstopped-- reschedule */
667                 init_timer(&wd_timer);
668                 wd_timer.expires = WD_BTIMEOUT;
669                 add_timer(&wd_timer);
670         }
671 }
672
673 static int wd_getstatus(struct wd_timer* pTimer)
674 {
675         unsigned char stat = wd_readb(pTimer->regs + WD_STATUS);
676         unsigned char intr = wd_readb(wd_dev.regs + PLD_IMASK);
677         unsigned char ret  = WD_STOPPED;
678
679         /* determine STOPPED */
680         if(0 == stat ) { 
681                 return(ret);
682         }
683         /* determine EXPIRED vs FREERUN vs RUNNING */
684         else if(WD_S_EXPIRED & stat) {
685                 ret = WD_EXPIRED;
686         }
687         else if(WD_S_RUNNING & stat) {
688                 if(intr & pTimer->intr_mask) {
689                         ret = WD_FREERUN;
690                 }
691                 else {
692                         /* Fudge WD_EXPIRED status for defective CP1400--
693                          * IF timer is running 
694                          *      AND brokenstop is set 
695                          *      AND an interrupt has been serviced
696                          * we are WD_EXPIRED.
697                          *
698                          * IF timer is running 
699                          *      AND brokenstop is set 
700                          *      AND no interrupt has been serviced
701                          * we are WD_FREERUN.
702                          */
703                         if(wd_dev.isbaddoggie && (pTimer->runstatus & WD_STAT_BSTOP)) {
704                                 if(pTimer->runstatus & WD_STAT_SVCD) {
705                                         ret = WD_EXPIRED;
706                                 }
707                                 else {
708                                         /* we could as well pretend we are expired */
709                                         ret = WD_FREERUN;
710                                 }
711                         }
712                         else {
713                                 ret = WD_RUNNING;
714                         }
715                 }
716         }
717
718         /* determine SERVICED */
719         if(pTimer->runstatus & WD_STAT_SVCD) {
720                 ret |= WD_SERVICED;
721         }
722
723         return(ret);
724 }
725
726 static int __init wd_init(void)
727 {
728         int     id;
729         struct  linux_ebus *ebus = NULL;
730         struct  linux_ebus_device *edev = NULL;
731
732         for_each_ebus(ebus) {
733                 for_each_ebusdev(edev, ebus) {
734                         if (!strcmp(edev->prom_name, WD_OBPNAME))
735                                 goto ebus_done;
736                 }
737         }
738
739 ebus_done:
740         if(!edev) {
741                 printk("%s: unable to locate device\n", WD_OBPNAME);
742                 return -ENODEV;
743         }
744
745         wd_dev.regs = 
746                 ioremap(edev->resource[0].start, 4 * WD_TIMER_REGSZ); /* ? */
747
748         if(NULL == wd_dev.regs) {
749                 printk("%s: unable to map registers\n", WD_OBPNAME);
750                 return(-ENODEV);
751         }
752
753         /* initialize device structure from OBP parameters */
754         wd_dev.irq                      = edev->irqs[0];
755         wd_dev.opt_enable       = wd_opt_enable();
756         wd_dev.opt_reboot       = wd_opt_reboot();
757         wd_dev.opt_timeout      = wd_opt_timeout();
758         wd_dev.isbaddoggie      = wd_isbroken();
759
760         /* disable all interrupts unless watchdog-enabled? == true */
761         if(! wd_dev.opt_enable) {
762                 wd_toggleintr(NULL, WD_INTR_OFF);
763         }
764
765         /* register miscellaneous devices */
766         for(id = WD0_ID; id < WD_NUMDEVS; ++id) {
767                 if(0 != wd_inittimer(id)) {
768                         printk("%s%i: unable to initialize\n", WD_OBPNAME, id);
769                 }
770         }
771
772         /* warn about possible defective PLD */
773         if(wd_dev.isbaddoggie) {
774                 init_timer(&wd_timer);
775                 wd_timer.function       = wd_brokentimer;
776                 wd_timer.data           = (unsigned long)&wd_dev;
777                 wd_timer.expires        = WD_BTIMEOUT;
778
779                 printk("%s: PLD defect workaround enabled for model %s\n",
780                         WD_OBPNAME, WD_BADMODEL);
781         }
782         return(0);
783 }
784
785 static void __exit wd_cleanup(void)
786 {
787         int id;
788
789         /* if 'watchdog-enable?' == TRUE, timers are not stopped 
790          * when module is unloaded.  All brokenstopped timers will
791          * also now eventually trip. 
792          */
793         for(id = WD0_ID; id < WD_NUMDEVS; ++id) {
794                 if(WD_S_RUNNING == wd_readb(wd_dev.watchdog[id].regs + WD_STATUS)) {
795                         if(wd_dev.opt_enable) {
796                                 printk(KERN_WARNING "%s%i: timer not stopped at release\n",
797                                         WD_OBPNAME, id);
798                         }
799                         else {
800                                 wd_stoptimer(&wd_dev.watchdog[id]);
801                                 if(wd_dev.watchdog[id].runstatus & WD_STAT_BSTOP) {
802                                         wd_resetbrokentimer(&wd_dev.watchdog[id]);
803                                         printk(KERN_WARNING 
804                                                         "%s%i: defect workaround disabled at release, "\
805                                                         "timer expires in ~%01i sec\n",
806                                                         WD_OBPNAME, id, 
807                                                         wd_readw(wd_dev.watchdog[id].regs + WD_LIMIT) / 10);
808                                 }
809                         }
810                 }
811         }
812
813         if(wd_dev.isbaddoggie && timer_pending(&wd_timer)) {
814                 del_timer(&wd_timer);
815         }
816         if(0 != (wd_dev.watchdog[WD0_ID].runstatus & WD_STAT_INIT)) {
817                 misc_deregister(&wd0_miscdev);
818         }
819         if(0 != (wd_dev.watchdog[WD1_ID].runstatus & WD_STAT_INIT)) {
820                 misc_deregister(&wd1_miscdev);
821         }
822         if(0 != (wd_dev.watchdog[WD2_ID].runstatus & WD_STAT_INIT)) {
823                 misc_deregister(&wd2_miscdev);
824         }
825         if(0 != wd_dev.initialized) {
826                 free_irq(wd_dev.irq, (void *)wd_dev.regs);
827         }
828         iounmap(wd_dev.regs);
829 }
830
831 module_init(wd_init);
832 module_exit(wd_cleanup);