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[linux-2.6.git] / drivers / watchdog / cpwd.c
1 /* cpwd.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  * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
15  */
16
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/fs.h>
20 #include <linux/errno.h>
21 #include <linux/major.h>
22 #include <linux/init.h>
23 #include <linux/miscdevice.h>
24 #include <linux/interrupt.h>
25 #include <linux/ioport.h>
26 #include <linux/timer.h>
27 #include <linux/smp_lock.h>
28 #include <linux/io.h>
29 #include <linux/of.h>
30 #include <linux/of_device.h>
31 #include <linux/uaccess.h>
32
33 #include <asm/irq.h>
34 #include <asm/watchdog.h>
35
36 #define DRIVER_NAME     "cpwd"
37 #define PFX             DRIVER_NAME ": "
38
39 #define WD_OBPNAME      "watchdog"
40 #define WD_BADMODEL     "SUNW,501-5336"
41 #define WD_BTIMEOUT     (jiffies + (HZ * 1000))
42 #define WD_BLIMIT       0xFFFF
43
44 #define WD0_MINOR       212
45 #define WD1_MINOR       213
46 #define WD2_MINOR       214
47
48 /* Internal driver definitions.  */
49 #define WD0_ID                  0
50 #define WD1_ID                  1
51 #define WD2_ID                  2
52 #define WD_NUMDEVS              3
53
54 #define WD_INTR_OFF             0
55 #define WD_INTR_ON              1
56
57 #define WD_STAT_INIT    0x01    /* Watchdog timer is initialized        */
58 #define WD_STAT_BSTOP   0x02    /* Watchdog timer is brokenstopped      */
59 #define WD_STAT_SVCD    0x04    /* Watchdog interrupt occurred          */
60
61 /* Register value definitions
62  */
63 #define WD0_INTR_MASK   0x01    /* Watchdog device interrupt masks      */
64 #define WD1_INTR_MASK   0x02
65 #define WD2_INTR_MASK   0x04
66
67 #define WD_S_RUNNING    0x01    /* Watchdog device status running       */
68 #define WD_S_EXPIRED    0x02    /* Watchdog device status expired       */
69
70 struct cpwd {
71         void __iomem    *regs;
72         spinlock_t      lock;
73
74         unsigned int    irq;
75
76         unsigned long   timeout;
77         bool            enabled;
78         bool            reboot;
79         bool            broken;
80         bool            initialized;
81
82         struct {
83                 struct miscdevice       misc;
84                 void __iomem            *regs;
85                 u8                      intr_mask;
86                 u8                      runstatus;
87                 u16                     timeout;
88         } devs[WD_NUMDEVS];
89 };
90
91 static struct cpwd *cpwd_device;
92
93 /* Sun uses Altera PLD EPF8820ATC144-4
94  * providing three hardware watchdogs:
95  *
96  * 1) RIC - sends an interrupt when triggered
97  * 2) XIR - asserts XIR_B_RESET when triggered, resets CPU
98  * 3) POR - asserts POR_B_RESET when triggered, resets CPU, backplane, board
99  *
100  *** Timer register block definition (struct wd_timer_regblk)
101  *
102  * dcntr and limit registers (halfword access):
103  * -------------------
104  * | 15 | ...| 1 | 0 |
105  * -------------------
106  * |-  counter val  -|
107  * -------------------
108  * dcntr -      Current 16-bit downcounter value.
109  *                      When downcounter reaches '0' watchdog expires.
110  *                      Reading this register resets downcounter with
111  *                      'limit' value.
112  * limit -      16-bit countdown value in 1/10th second increments.
113  *                      Writing this register begins countdown with input value.
114  *                      Reading from this register does not affect counter.
115  * NOTES:       After watchdog reset, dcntr and limit contain '1'
116  *
117  * status register (byte access):
118  * ---------------------------
119  * | 7 | ... | 2 |  1  |  0  |
120  * --------------+------------
121  * |-   UNUSED  -| EXP | RUN |
122  * ---------------------------
123  * status-      Bit 0 - Watchdog is running
124  *                      Bit 1 - Watchdog has expired
125  *
126  *** PLD register block definition (struct wd_pld_regblk)
127  *
128  * intr_mask register (byte access):
129  * ---------------------------------
130  * | 7 | ... | 3 |  2  |  1  |  0  |
131  * +-------------+------------------
132  * |-   UNUSED  -| WD3 | WD2 | WD1 |
133  * ---------------------------------
134  * WD3 -  1 == Interrupt disabled for watchdog 3
135  * WD2 -  1 == Interrupt disabled for watchdog 2
136  * WD1 -  1 == Interrupt disabled for watchdog 1
137  *
138  * pld_status register (byte access):
139  * UNKNOWN, MAGICAL MYSTERY REGISTER
140  *
141  */
142 #define WD_TIMER_REGSZ  16
143 #define WD0_OFF         0
144 #define WD1_OFF         (WD_TIMER_REGSZ * 1)
145 #define WD2_OFF         (WD_TIMER_REGSZ * 2)
146 #define PLD_OFF         (WD_TIMER_REGSZ * 3)
147
148 #define WD_DCNTR        0x00
149 #define WD_LIMIT        0x04
150 #define WD_STATUS       0x08
151
152 #define PLD_IMASK       (PLD_OFF + 0x00)
153 #define PLD_STATUS      (PLD_OFF + 0x04)
154
155 static struct timer_list cpwd_timer;
156
157 static int wd0_timeout = 0;
158 static int wd1_timeout = 0;
159 static int wd2_timeout = 0;
160
161 module_param(wd0_timeout, int, 0);
162 MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs");
163 module_param(wd1_timeout, int, 0);
164 MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs");
165 module_param(wd2_timeout, int, 0);
166 MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs");
167
168 MODULE_AUTHOR("Eric Brower <ebrower@usa.net>");
169 MODULE_DESCRIPTION("Hardware watchdog driver for Sun Microsystems CP1400/1500");
170 MODULE_LICENSE("GPL");
171 MODULE_SUPPORTED_DEVICE("watchdog");
172
173 static void cpwd_writew(u16 val, void __iomem *addr)
174 {
175         writew(cpu_to_le16(val), addr);
176 }
177 static u16 cpwd_readw(void __iomem *addr)
178 {
179         u16 val = readw(addr);
180
181         return le16_to_cpu(val);
182 }
183
184 static void cpwd_writeb(u8 val, void __iomem *addr)
185 {
186         writeb(val, addr);
187 }
188
189 static u8 cpwd_readb(void __iomem *addr)
190 {
191         return readb(addr);
192 }
193
194 /* Enable or disable watchdog interrupts
195  * Because of the CP1400 defect this should only be
196  * called during initialzation or by wd_[start|stop]timer()
197  *
198  * index        - sub-device index, or -1 for 'all'
199  * enable       - non-zero to enable interrupts, zero to disable
200  */
201 static void cpwd_toggleintr(struct cpwd *p, int index, int enable)
202 {
203         unsigned char curregs = cpwd_readb(p->regs + PLD_IMASK);
204         unsigned char setregs =
205                 (index == -1) ?
206                 (WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) :
207                 (p->devs[index].intr_mask);
208
209         if (enable == WD_INTR_ON)
210                 curregs &= ~setregs;
211         else
212                 curregs |= setregs;
213
214         cpwd_writeb(curregs, p->regs + PLD_IMASK);
215 }
216
217 /* Restarts timer with maximum limit value and
218  * does not unset 'brokenstop' value.
219  */
220 static void cpwd_resetbrokentimer(struct cpwd *p, int index)
221 {
222         cpwd_toggleintr(p, index, WD_INTR_ON);
223         cpwd_writew(WD_BLIMIT, p->devs[index].regs + WD_LIMIT);
224 }
225
226 /* Timer method called to reset stopped watchdogs--
227  * because of the PLD bug on CP1400, we cannot mask
228  * interrupts within the PLD so me must continually
229  * reset the timers ad infinitum.
230  */
231 static void cpwd_brokentimer(unsigned long data)
232 {
233         struct cpwd *p = (struct cpwd *) data;
234         int id, tripped = 0;
235
236         /* kill a running timer instance, in case we
237          * were called directly instead of by kernel timer
238          */
239         if (timer_pending(&cpwd_timer))
240                 del_timer(&cpwd_timer);
241
242         for (id = 0; id < WD_NUMDEVS; id++) {
243                 if (p->devs[id].runstatus & WD_STAT_BSTOP) {
244                         ++tripped;
245                         cpwd_resetbrokentimer(p, id);
246                 }
247         }
248
249         if (tripped) {
250                 /* there is at least one timer brokenstopped-- reschedule */
251                 cpwd_timer.expires = WD_BTIMEOUT;
252                 add_timer(&cpwd_timer);
253         }
254 }
255
256 /* Reset countdown timer with 'limit' value and continue countdown.
257  * This will not start a stopped timer.
258  */
259 static void cpwd_pingtimer(struct cpwd *p, int index)
260 {
261         if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING)
262                 cpwd_readw(p->devs[index].regs + WD_DCNTR);
263 }
264
265 /* Stop a running watchdog timer-- the timer actually keeps
266  * running, but the interrupt is masked so that no action is
267  * taken upon expiration.
268  */
269 static void cpwd_stoptimer(struct cpwd *p, int index)
270 {
271         if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING) {
272                 cpwd_toggleintr(p, index, WD_INTR_OFF);
273
274                 if (p->broken) {
275                         p->devs[index].runstatus |= WD_STAT_BSTOP;
276                         cpwd_brokentimer((unsigned long) p);
277                 }
278         }
279 }
280
281 /* Start a watchdog timer with the specified limit value
282  * If the watchdog is running, it will be restarted with
283  * the provided limit value.
284  *
285  * This function will enable interrupts on the specified
286  * watchdog.
287  */
288 static void cpwd_starttimer(struct cpwd *p, int index)
289 {
290         if (p->broken)
291                 p->devs[index].runstatus &= ~WD_STAT_BSTOP;
292
293         p->devs[index].runstatus &= ~WD_STAT_SVCD;
294
295         cpwd_writew(p->devs[index].timeout, p->devs[index].regs + WD_LIMIT);
296         cpwd_toggleintr(p, index, WD_INTR_ON);
297 }
298
299 static int cpwd_getstatus(struct cpwd *p, int index)
300 {
301         unsigned char stat = cpwd_readb(p->devs[index].regs + WD_STATUS);
302         unsigned char intr = cpwd_readb(p->devs[index].regs + PLD_IMASK);
303         unsigned char ret  = WD_STOPPED;
304
305         /* determine STOPPED */
306         if (!stat)
307                 return ret;
308
309         /* determine EXPIRED vs FREERUN vs RUNNING */
310         else if (WD_S_EXPIRED & stat) {
311                 ret = WD_EXPIRED;
312         } else if (WD_S_RUNNING & stat) {
313                 if (intr & p->devs[index].intr_mask) {
314                         ret = WD_FREERUN;
315                 } else {
316                         /* Fudge WD_EXPIRED status for defective CP1400--
317                          * IF timer is running
318                          *      AND brokenstop is set
319                          *      AND an interrupt has been serviced
320                          * we are WD_EXPIRED.
321                          *
322                          * IF timer is running
323                          *      AND brokenstop is set
324                          *      AND no interrupt has been serviced
325                          * we are WD_FREERUN.
326                          */
327                         if (p->broken &&
328                             (p->devs[index].runstatus & WD_STAT_BSTOP)) {
329                                 if (p->devs[index].runstatus & WD_STAT_SVCD) {
330                                         ret = WD_EXPIRED;
331                                 } else {
332                                         /* we could as well pretend
333                                          * we are expired */
334                                         ret = WD_FREERUN;
335                                 }
336                         } else {
337                                 ret = WD_RUNNING;
338                         }
339                 }
340         }
341
342         /* determine SERVICED */
343         if (p->devs[index].runstatus & WD_STAT_SVCD)
344                 ret |= WD_SERVICED;
345
346         return ret;
347 }
348
349 static irqreturn_t cpwd_interrupt(int irq, void *dev_id)
350 {
351         struct cpwd *p = dev_id;
352
353         /* Only WD0 will interrupt-- others are NMI and we won't
354          * see them here....
355          */
356         spin_lock_irq(&p->lock);
357
358         cpwd_stoptimer(p, WD0_ID);
359         p->devs[WD0_ID].runstatus |=  WD_STAT_SVCD;
360
361         spin_unlock_irq(&p->lock);
362
363         return IRQ_HANDLED;
364 }
365
366 static int cpwd_open(struct inode *inode, struct file *f)
367 {
368         struct cpwd *p = cpwd_device;
369
370         lock_kernel();
371         switch (iminor(inode)) {
372         case WD0_MINOR:
373         case WD1_MINOR:
374         case WD2_MINOR:
375                 break;
376
377         default:
378                 unlock_kernel();
379                 return -ENODEV;
380         }
381
382         /* Register IRQ on first open of device */
383         if (!p->initialized) {
384                 if (request_irq(p->irq, &cpwd_interrupt,
385                                 IRQF_SHARED, DRIVER_NAME, p)) {
386                         printk(KERN_ERR PFX "Cannot register IRQ %d\n",
387                                 p->irq);
388                         unlock_kernel();
389                         return -EBUSY;
390                 }
391                 p->initialized = true;
392         }
393
394         unlock_kernel();
395
396         return nonseekable_open(inode, f);
397 }
398
399 static int cpwd_release(struct inode *inode, struct file *file)
400 {
401         return 0;
402 }
403
404 static long cpwd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
405 {
406         static struct watchdog_info info = {
407                 .options                = WDIOF_SETTIMEOUT,
408                 .firmware_version       = 1,
409                 .identity               = DRIVER_NAME,
410         };
411         void __user *argp = (void __user *)arg;
412         struct inode *inode = file->f_path.dentry->d_inode;
413         int index = iminor(inode) - WD0_MINOR;
414         struct cpwd *p = cpwd_device;
415         int setopt = 0;
416
417         switch (cmd) {
418         /* Generic Linux IOCTLs */
419         case WDIOC_GETSUPPORT:
420                 if (copy_to_user(argp, &info, sizeof(struct watchdog_info)))
421                         return -EFAULT;
422                 break;
423
424         case WDIOC_GETSTATUS:
425         case WDIOC_GETBOOTSTATUS:
426                 if (put_user(0, (int __user *)argp))
427                         return -EFAULT;
428                 break;
429
430         case WDIOC_KEEPALIVE:
431                 cpwd_pingtimer(p, index);
432                 break;
433
434         case WDIOC_SETOPTIONS:
435                 if (copy_from_user(&setopt, argp, sizeof(unsigned int)))
436                         return -EFAULT;
437
438                 if (setopt & WDIOS_DISABLECARD) {
439                         if (p->enabled)
440                                 return -EINVAL;
441                         cpwd_stoptimer(p, index);
442                 } else if (setopt & WDIOS_ENABLECARD) {
443                         cpwd_starttimer(p, index);
444                 } else {
445                         return -EINVAL;
446                 }
447                 break;
448
449         /* Solaris-compatible IOCTLs */
450         case WIOCGSTAT:
451                 setopt = cpwd_getstatus(p, index);
452                 if (copy_to_user(argp, &setopt, sizeof(unsigned int)))
453                         return -EFAULT;
454                 break;
455
456         case WIOCSTART:
457                 cpwd_starttimer(p, index);
458                 break;
459
460         case WIOCSTOP:
461                 if (p->enabled)
462                         return -EINVAL;
463
464                 cpwd_stoptimer(p, index);
465                 break;
466
467         default:
468                 return -EINVAL;
469         }
470
471         return 0;
472 }
473
474 static long cpwd_compat_ioctl(struct file *file, unsigned int cmd,
475                               unsigned long arg)
476 {
477         int rval = -ENOIOCTLCMD;
478
479         switch (cmd) {
480         /* solaris ioctls are specific to this driver */
481         case WIOCSTART:
482         case WIOCSTOP:
483         case WIOCGSTAT:
484                 lock_kernel();
485                 rval = cpwd_ioctl(file, cmd, arg);
486                 unlock_kernel();
487                 break;
488
489         /* everything else is handled by the generic compat layer */
490         default:
491                 break;
492         }
493
494         return rval;
495 }
496
497 static ssize_t cpwd_write(struct file *file, const char __user *buf,
498                           size_t count, loff_t *ppos)
499 {
500         struct inode *inode = file->f_path.dentry->d_inode;
501         struct cpwd *p = cpwd_device;
502         int index = iminor(inode);
503
504         if (count) {
505                 cpwd_pingtimer(p, index);
506                 return 1;
507         }
508
509         return 0;
510 }
511
512 static ssize_t cpwd_read(struct file *file, char __user *buffer,
513                          size_t count, loff_t *ppos)
514 {
515         return -EINVAL;
516 }
517
518 static const struct file_operations cpwd_fops = {
519         .owner =                THIS_MODULE,
520         .unlocked_ioctl =       cpwd_ioctl,
521         .compat_ioctl =         cpwd_compat_ioctl,
522         .open =                 cpwd_open,
523         .write =                cpwd_write,
524         .read =                 cpwd_read,
525         .release =              cpwd_release,
526 };
527
528 static int __devinit cpwd_probe(struct of_device *op,
529                                 const struct of_device_id *match)
530 {
531         struct device_node *options;
532         const char *str_prop;
533         const void *prop_val;
534         int i, err = -EINVAL;
535         struct cpwd *p;
536
537         if (cpwd_device)
538                 return -EINVAL;
539
540         p = kzalloc(sizeof(*p), GFP_KERNEL);
541         err = -ENOMEM;
542         if (!p) {
543                 printk(KERN_ERR PFX "Unable to allocate struct cpwd.\n");
544                 goto out;
545         }
546
547         p->irq = op->irqs[0];
548
549         spin_lock_init(&p->lock);
550
551         p->regs = of_ioremap(&op->resource[0], 0,
552                              4 * WD_TIMER_REGSZ, DRIVER_NAME);
553         if (!p->regs) {
554                 printk(KERN_ERR PFX "Unable to map registers.\n");
555                 goto out_free;
556         }
557
558         options = of_find_node_by_path("/options");
559         err = -ENODEV;
560         if (!options) {
561                 printk(KERN_ERR PFX "Unable to find /options node.\n");
562                 goto out_iounmap;
563         }
564
565         prop_val = of_get_property(options, "watchdog-enable?", NULL);
566         p->enabled = (prop_val ? true : false);
567
568         prop_val = of_get_property(options, "watchdog-reboot?", NULL);
569         p->reboot = (prop_val ? true : false);
570
571         str_prop = of_get_property(options, "watchdog-timeout", NULL);
572         if (str_prop)
573                 p->timeout = simple_strtoul(str_prop, NULL, 10);
574
575         /* CP1400s seem to have broken PLD implementations-- the
576          * interrupt_mask register cannot be written, so no timer
577          * interrupts can be masked within the PLD.
578          */
579         str_prop = of_get_property(op->node, "model", NULL);
580         p->broken = (str_prop && !strcmp(str_prop, WD_BADMODEL));
581
582         if (!p->enabled)
583                 cpwd_toggleintr(p, -1, WD_INTR_OFF);
584
585         for (i = 0; i < WD_NUMDEVS; i++) {
586                 static const char *cpwd_names[] = { "RIC", "XIR", "POR" };
587                 static int *parms[] = { &wd0_timeout,
588                                         &wd1_timeout,
589                                         &wd2_timeout };
590                 struct miscdevice *mp = &p->devs[i].misc;
591
592                 mp->minor = WD0_MINOR + i;
593                 mp->name = cpwd_names[i];
594                 mp->fops = &cpwd_fops;
595
596                 p->devs[i].regs = p->regs + (i * WD_TIMER_REGSZ);
597                 p->devs[i].intr_mask = (WD0_INTR_MASK << i);
598                 p->devs[i].runstatus &= ~WD_STAT_BSTOP;
599                 p->devs[i].runstatus |= WD_STAT_INIT;
600                 p->devs[i].timeout = p->timeout;
601                 if (*parms[i])
602                         p->devs[i].timeout = *parms[i];
603
604                 err = misc_register(&p->devs[i].misc);
605                 if (err) {
606                         printk(KERN_ERR "Could not register misc device for "
607                                "dev %d\n", i);
608                         goto out_unregister;
609                 }
610         }
611
612         if (p->broken) {
613                 init_timer(&cpwd_timer);
614                 cpwd_timer.function     = cpwd_brokentimer;
615                 cpwd_timer.data         = (unsigned long) p;
616                 cpwd_timer.expires      = WD_BTIMEOUT;
617
618                 printk(KERN_INFO PFX "PLD defect workaround enabled for "
619                        "model " WD_BADMODEL ".\n");
620         }
621
622         dev_set_drvdata(&op->dev, p);
623         cpwd_device = p;
624         err = 0;
625
626 out:
627         return err;
628
629 out_unregister:
630         for (i--; i >= 0; i--)
631                 misc_deregister(&p->devs[i].misc);
632
633 out_iounmap:
634         of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
635
636 out_free:
637         kfree(p);
638         goto out;
639 }
640
641 static int __devexit cpwd_remove(struct of_device *op)
642 {
643         struct cpwd *p = dev_get_drvdata(&op->dev);
644         int i;
645
646         for (i = 0; i < 4; i++) {
647                 misc_deregister(&p->devs[i].misc);
648
649                 if (!p->enabled) {
650                         cpwd_stoptimer(p, i);
651                         if (p->devs[i].runstatus & WD_STAT_BSTOP)
652                                 cpwd_resetbrokentimer(p, i);
653                 }
654         }
655
656         if (p->broken)
657                 del_timer_sync(&cpwd_timer);
658
659         if (p->initialized)
660                 free_irq(p->irq, p);
661
662         of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
663         kfree(p);
664
665         cpwd_device = NULL;
666
667         return 0;
668 }
669
670 static const struct of_device_id cpwd_match[] = {
671         {
672                 .name = "watchdog",
673         },
674         {},
675 };
676 MODULE_DEVICE_TABLE(of, cpwd_match);
677
678 static struct of_platform_driver cpwd_driver = {
679         .name           = DRIVER_NAME,
680         .match_table    = cpwd_match,
681         .probe          = cpwd_probe,
682         .remove         = __devexit_p(cpwd_remove),
683 };
684
685 static int __init cpwd_init(void)
686 {
687         return of_register_driver(&cpwd_driver, &of_bus_type);
688 }
689
690 static void __exit cpwd_exit(void)
691 {
692         of_unregister_driver(&cpwd_driver);
693 }
694
695 module_init(cpwd_init);
696 module_exit(cpwd_exit);