parport_pc: show the detection of a 2 serial port ITE8874 chip
[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/slab.h>
28 #include <linux/smp_lock.h>
29 #include <linux/io.h>
30 #include <linux/of.h>
31 #include <linux/of_device.h>
32 #include <linux/uaccess.h>
33
34 #include <asm/irq.h>
35 #include <asm/watchdog.h>
36
37 #define DRIVER_NAME     "cpwd"
38 #define PFX             DRIVER_NAME ": "
39
40 #define WD_OBPNAME      "watchdog"
41 #define WD_BADMODEL     "SUNW,501-5336"
42 #define WD_BTIMEOUT     (jiffies + (HZ * 1000))
43 #define WD_BLIMIT       0xFFFF
44
45 #define WD0_MINOR       212
46 #define WD1_MINOR       213
47 #define WD2_MINOR       214
48
49 /* Internal driver definitions.  */
50 #define WD0_ID                  0
51 #define WD1_ID                  1
52 #define WD2_ID                  2
53 #define WD_NUMDEVS              3
54
55 #define WD_INTR_OFF             0
56 #define WD_INTR_ON              1
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 struct cpwd {
72         void __iomem    *regs;
73         spinlock_t      lock;
74
75         unsigned int    irq;
76
77         unsigned long   timeout;
78         bool            enabled;
79         bool            reboot;
80         bool            broken;
81         bool            initialized;
82
83         struct {
84                 struct miscdevice       misc;
85                 void __iomem            *regs;
86                 u8                      intr_mask;
87                 u8                      runstatus;
88                 u16                     timeout;
89         } devs[WD_NUMDEVS];
90 };
91
92 static struct cpwd *cpwd_device;
93
94 /* Sun uses Altera PLD EPF8820ATC144-4
95  * providing three hardware watchdogs:
96  *
97  * 1) RIC - sends an interrupt when triggered
98  * 2) XIR - asserts XIR_B_RESET when triggered, resets CPU
99  * 3) POR - asserts POR_B_RESET when triggered, resets CPU, backplane, board
100  *
101  *** Timer register block definition (struct wd_timer_regblk)
102  *
103  * dcntr and limit registers (halfword access):
104  * -------------------
105  * | 15 | ...| 1 | 0 |
106  * -------------------
107  * |-  counter val  -|
108  * -------------------
109  * dcntr -      Current 16-bit downcounter value.
110  *                      When downcounter reaches '0' watchdog expires.
111  *                      Reading this register resets downcounter with
112  *                      'limit' value.
113  * limit -      16-bit countdown value in 1/10th second increments.
114  *                      Writing this register begins countdown with input value.
115  *                      Reading from this register does not affect counter.
116  * NOTES:       After watchdog reset, dcntr and limit contain '1'
117  *
118  * status register (byte access):
119  * ---------------------------
120  * | 7 | ... | 2 |  1  |  0  |
121  * --------------+------------
122  * |-   UNUSED  -| EXP | RUN |
123  * ---------------------------
124  * status-      Bit 0 - Watchdog is running
125  *                      Bit 1 - Watchdog has expired
126  *
127  *** PLD register block definition (struct wd_pld_regblk)
128  *
129  * intr_mask register (byte access):
130  * ---------------------------------
131  * | 7 | ... | 3 |  2  |  1  |  0  |
132  * +-------------+------------------
133  * |-   UNUSED  -| WD3 | WD2 | WD1 |
134  * ---------------------------------
135  * WD3 -  1 == Interrupt disabled for watchdog 3
136  * WD2 -  1 == Interrupt disabled for watchdog 2
137  * WD1 -  1 == Interrupt disabled for watchdog 1
138  *
139  * pld_status register (byte access):
140  * UNKNOWN, MAGICAL MYSTERY REGISTER
141  *
142  */
143 #define WD_TIMER_REGSZ  16
144 #define WD0_OFF         0
145 #define WD1_OFF         (WD_TIMER_REGSZ * 1)
146 #define WD2_OFF         (WD_TIMER_REGSZ * 2)
147 #define PLD_OFF         (WD_TIMER_REGSZ * 3)
148
149 #define WD_DCNTR        0x00
150 #define WD_LIMIT        0x04
151 #define WD_STATUS       0x08
152
153 #define PLD_IMASK       (PLD_OFF + 0x00)
154 #define PLD_STATUS      (PLD_OFF + 0x04)
155
156 static struct timer_list cpwd_timer;
157
158 static int wd0_timeout;
159 static int wd1_timeout;
160 static int wd2_timeout;
161
162 module_param(wd0_timeout, int, 0);
163 MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs");
164 module_param(wd1_timeout, int, 0);
165 MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs");
166 module_param(wd2_timeout, int, 0);
167 MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs");
168
169 MODULE_AUTHOR("Eric Brower <ebrower@usa.net>");
170 MODULE_DESCRIPTION("Hardware watchdog driver for Sun Microsystems CP1400/1500");
171 MODULE_LICENSE("GPL");
172 MODULE_SUPPORTED_DEVICE("watchdog");
173
174 static void cpwd_writew(u16 val, void __iomem *addr)
175 {
176         writew(cpu_to_le16(val), addr);
177 }
178 static u16 cpwd_readw(void __iomem *addr)
179 {
180         u16 val = readw(addr);
181
182         return le16_to_cpu(val);
183 }
184
185 static void cpwd_writeb(u8 val, void __iomem *addr)
186 {
187         writeb(val, addr);
188 }
189
190 static u8 cpwd_readb(void __iomem *addr)
191 {
192         return readb(addr);
193 }
194
195 /* Enable or disable watchdog interrupts
196  * Because of the CP1400 defect this should only be
197  * called during initialzation or by wd_[start|stop]timer()
198  *
199  * index        - sub-device index, or -1 for 'all'
200  * enable       - non-zero to enable interrupts, zero to disable
201  */
202 static void cpwd_toggleintr(struct cpwd *p, int index, int enable)
203 {
204         unsigned char curregs = cpwd_readb(p->regs + PLD_IMASK);
205         unsigned char setregs =
206                 (index == -1) ?
207                 (WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) :
208                 (p->devs[index].intr_mask);
209
210         if (enable == WD_INTR_ON)
211                 curregs &= ~setregs;
212         else
213                 curregs |= setregs;
214
215         cpwd_writeb(curregs, p->regs + PLD_IMASK);
216 }
217
218 /* Restarts timer with maximum limit value and
219  * does not unset 'brokenstop' value.
220  */
221 static void cpwd_resetbrokentimer(struct cpwd *p, int index)
222 {
223         cpwd_toggleintr(p, index, WD_INTR_ON);
224         cpwd_writew(WD_BLIMIT, p->devs[index].regs + WD_LIMIT);
225 }
226
227 /* Timer method called to reset stopped watchdogs--
228  * because of the PLD bug on CP1400, we cannot mask
229  * interrupts within the PLD so me must continually
230  * reset the timers ad infinitum.
231  */
232 static void cpwd_brokentimer(unsigned long data)
233 {
234         struct cpwd *p = (struct cpwd *) data;
235         int id, tripped = 0;
236
237         /* kill a running timer instance, in case we
238          * were called directly instead of by kernel timer
239          */
240         if (timer_pending(&cpwd_timer))
241                 del_timer(&cpwd_timer);
242
243         for (id = 0; id < WD_NUMDEVS; id++) {
244                 if (p->devs[id].runstatus & WD_STAT_BSTOP) {
245                         ++tripped;
246                         cpwd_resetbrokentimer(p, id);
247                 }
248         }
249
250         if (tripped) {
251                 /* there is at least one timer brokenstopped-- reschedule */
252                 cpwd_timer.expires = WD_BTIMEOUT;
253                 add_timer(&cpwd_timer);
254         }
255 }
256
257 /* Reset countdown timer with 'limit' value and continue countdown.
258  * This will not start a stopped timer.
259  */
260 static void cpwd_pingtimer(struct cpwd *p, int index)
261 {
262         if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING)
263                 cpwd_readw(p->devs[index].regs + WD_DCNTR);
264 }
265
266 /* Stop a running watchdog timer-- the timer actually keeps
267  * running, but the interrupt is masked so that no action is
268  * taken upon expiration.
269  */
270 static void cpwd_stoptimer(struct cpwd *p, int index)
271 {
272         if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING) {
273                 cpwd_toggleintr(p, index, WD_INTR_OFF);
274
275                 if (p->broken) {
276                         p->devs[index].runstatus |= WD_STAT_BSTOP;
277                         cpwd_brokentimer((unsigned long) p);
278                 }
279         }
280 }
281
282 /* Start a watchdog timer with the specified limit value
283  * If the watchdog is running, it will be restarted with
284  * the provided limit value.
285  *
286  * This function will enable interrupts on the specified
287  * watchdog.
288  */
289 static void cpwd_starttimer(struct cpwd *p, int index)
290 {
291         if (p->broken)
292                 p->devs[index].runstatus &= ~WD_STAT_BSTOP;
293
294         p->devs[index].runstatus &= ~WD_STAT_SVCD;
295
296         cpwd_writew(p->devs[index].timeout, p->devs[index].regs + WD_LIMIT);
297         cpwd_toggleintr(p, index, WD_INTR_ON);
298 }
299
300 static int cpwd_getstatus(struct cpwd *p, int index)
301 {
302         unsigned char stat = cpwd_readb(p->devs[index].regs + WD_STATUS);
303         unsigned char intr = cpwd_readb(p->devs[index].regs + PLD_IMASK);
304         unsigned char ret  = WD_STOPPED;
305
306         /* determine STOPPED */
307         if (!stat)
308                 return ret;
309
310         /* determine EXPIRED vs FREERUN vs RUNNING */
311         else if (WD_S_EXPIRED & stat) {
312                 ret = WD_EXPIRED;
313         } else if (WD_S_RUNNING & stat) {
314                 if (intr & p->devs[index].intr_mask) {
315                         ret = WD_FREERUN;
316                 } else {
317                         /* Fudge WD_EXPIRED status for defective CP1400--
318                          * IF timer is running
319                          *      AND brokenstop is set
320                          *      AND an interrupt has been serviced
321                          * we are WD_EXPIRED.
322                          *
323                          * IF timer is running
324                          *      AND brokenstop is set
325                          *      AND no interrupt has been serviced
326                          * we are WD_FREERUN.
327                          */
328                         if (p->broken &&
329                             (p->devs[index].runstatus & WD_STAT_BSTOP)) {
330                                 if (p->devs[index].runstatus & WD_STAT_SVCD) {
331                                         ret = WD_EXPIRED;
332                                 } else {
333                                         /* we could as well pretend
334                                          * we are expired */
335                                         ret = WD_FREERUN;
336                                 }
337                         } else {
338                                 ret = WD_RUNNING;
339                         }
340                 }
341         }
342
343         /* determine SERVICED */
344         if (p->devs[index].runstatus & WD_STAT_SVCD)
345                 ret |= WD_SERVICED;
346
347         return ret;
348 }
349
350 static irqreturn_t cpwd_interrupt(int irq, void *dev_id)
351 {
352         struct cpwd *p = dev_id;
353
354         /* Only WD0 will interrupt-- others are NMI and we won't
355          * see them here....
356          */
357         spin_lock_irq(&p->lock);
358
359         cpwd_stoptimer(p, WD0_ID);
360         p->devs[WD0_ID].runstatus |=  WD_STAT_SVCD;
361
362         spin_unlock_irq(&p->lock);
363
364         return IRQ_HANDLED;
365 }
366
367 static int cpwd_open(struct inode *inode, struct file *f)
368 {
369         struct cpwd *p = cpwd_device;
370
371         lock_kernel();
372         switch (iminor(inode)) {
373         case WD0_MINOR:
374         case WD1_MINOR:
375         case WD2_MINOR:
376                 break;
377
378         default:
379                 unlock_kernel();
380                 return -ENODEV;
381         }
382
383         /* Register IRQ on first open of device */
384         if (!p->initialized) {
385                 if (request_irq(p->irq, &cpwd_interrupt,
386                                 IRQF_SHARED, DRIVER_NAME, p)) {
387                         printk(KERN_ERR PFX "Cannot register IRQ %d\n",
388                                 p->irq);
389                         unlock_kernel();
390                         return -EBUSY;
391                 }
392                 p->initialized = true;
393         }
394
395         unlock_kernel();
396
397         return nonseekable_open(inode, f);
398 }
399
400 static int cpwd_release(struct inode *inode, struct file *file)
401 {
402         return 0;
403 }
404
405 static long cpwd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
406 {
407         static const struct watchdog_info info = {
408                 .options                = WDIOF_SETTIMEOUT,
409                 .firmware_version       = 1,
410                 .identity               = DRIVER_NAME,
411         };
412         void __user *argp = (void __user *)arg;
413         struct inode *inode = file->f_path.dentry->d_inode;
414         int index = iminor(inode) - WD0_MINOR;
415         struct cpwd *p = cpwd_device;
416         int setopt = 0;
417
418         switch (cmd) {
419         /* Generic Linux IOCTLs */
420         case WDIOC_GETSUPPORT:
421                 if (copy_to_user(argp, &info, sizeof(struct watchdog_info)))
422                         return -EFAULT;
423                 break;
424
425         case WDIOC_GETSTATUS:
426         case WDIOC_GETBOOTSTATUS:
427                 if (put_user(0, (int __user *)argp))
428                         return -EFAULT;
429                 break;
430
431         case WDIOC_KEEPALIVE:
432                 cpwd_pingtimer(p, index);
433                 break;
434
435         case WDIOC_SETOPTIONS:
436                 if (copy_from_user(&setopt, argp, sizeof(unsigned int)))
437                         return -EFAULT;
438
439                 if (setopt & WDIOS_DISABLECARD) {
440                         if (p->enabled)
441                                 return -EINVAL;
442                         cpwd_stoptimer(p, index);
443                 } else if (setopt & WDIOS_ENABLECARD) {
444                         cpwd_starttimer(p, index);
445                 } else {
446                         return -EINVAL;
447                 }
448                 break;
449
450         /* Solaris-compatible IOCTLs */
451         case WIOCGSTAT:
452                 setopt = cpwd_getstatus(p, index);
453                 if (copy_to_user(argp, &setopt, sizeof(unsigned int)))
454                         return -EFAULT;
455                 break;
456
457         case WIOCSTART:
458                 cpwd_starttimer(p, index);
459                 break;
460
461         case WIOCSTOP:
462                 if (p->enabled)
463                         return -EINVAL;
464
465                 cpwd_stoptimer(p, index);
466                 break;
467
468         default:
469                 return -EINVAL;
470         }
471
472         return 0;
473 }
474
475 static long cpwd_compat_ioctl(struct file *file, unsigned int cmd,
476                               unsigned long arg)
477 {
478         int rval = -ENOIOCTLCMD;
479
480         switch (cmd) {
481         /* solaris ioctls are specific to this driver */
482         case WIOCSTART:
483         case WIOCSTOP:
484         case WIOCGSTAT:
485                 lock_kernel();
486                 rval = cpwd_ioctl(file, cmd, arg);
487                 unlock_kernel();
488                 break;
489
490         /* everything else is handled by the generic compat layer */
491         default:
492                 break;
493         }
494
495         return rval;
496 }
497
498 static ssize_t cpwd_write(struct file *file, const char __user *buf,
499                           size_t count, loff_t *ppos)
500 {
501         struct inode *inode = file->f_path.dentry->d_inode;
502         struct cpwd *p = cpwd_device;
503         int index = iminor(inode);
504
505         if (count) {
506                 cpwd_pingtimer(p, index);
507                 return 1;
508         }
509
510         return 0;
511 }
512
513 static ssize_t cpwd_read(struct file *file, char __user *buffer,
514                          size_t count, loff_t *ppos)
515 {
516         return -EINVAL;
517 }
518
519 static const struct file_operations cpwd_fops = {
520         .owner =                THIS_MODULE,
521         .unlocked_ioctl =       cpwd_ioctl,
522         .compat_ioctl =         cpwd_compat_ioctl,
523         .open =                 cpwd_open,
524         .write =                cpwd_write,
525         .read =                 cpwd_read,
526         .release =              cpwd_release,
527 };
528
529 static int __devinit cpwd_probe(struct of_device *op,
530                                 const struct of_device_id *match)
531 {
532         struct device_node *options;
533         const char *str_prop;
534         const void *prop_val;
535         int i, err = -EINVAL;
536         struct cpwd *p;
537
538         if (cpwd_device)
539                 return -EINVAL;
540
541         p = kzalloc(sizeof(*p), GFP_KERNEL);
542         err = -ENOMEM;
543         if (!p) {
544                 printk(KERN_ERR PFX "Unable to allocate struct cpwd.\n");
545                 goto out;
546         }
547
548         p->irq = op->archdata.irqs[0];
549
550         spin_lock_init(&p->lock);
551
552         p->regs = of_ioremap(&op->resource[0], 0,
553                              4 * WD_TIMER_REGSZ, DRIVER_NAME);
554         if (!p->regs) {
555                 printk(KERN_ERR PFX "Unable to map registers.\n");
556                 goto out_free;
557         }
558
559         options = of_find_node_by_path("/options");
560         err = -ENODEV;
561         if (!options) {
562                 printk(KERN_ERR PFX "Unable to find /options node.\n");
563                 goto out_iounmap;
564         }
565
566         prop_val = of_get_property(options, "watchdog-enable?", NULL);
567         p->enabled = (prop_val ? true : false);
568
569         prop_val = of_get_property(options, "watchdog-reboot?", NULL);
570         p->reboot = (prop_val ? true : false);
571
572         str_prop = of_get_property(options, "watchdog-timeout", NULL);
573         if (str_prop)
574                 p->timeout = simple_strtoul(str_prop, NULL, 10);
575
576         /* CP1400s seem to have broken PLD implementations-- the
577          * interrupt_mask register cannot be written, so no timer
578          * interrupts can be masked within the PLD.
579          */
580         str_prop = of_get_property(op->dev.of_node, "model", NULL);
581         p->broken = (str_prop && !strcmp(str_prop, WD_BADMODEL));
582
583         if (!p->enabled)
584                 cpwd_toggleintr(p, -1, WD_INTR_OFF);
585
586         for (i = 0; i < WD_NUMDEVS; i++) {
587                 static const char *cpwd_names[] = { "RIC", "XIR", "POR" };
588                 static int *parms[] = { &wd0_timeout,
589                                         &wd1_timeout,
590                                         &wd2_timeout };
591                 struct miscdevice *mp = &p->devs[i].misc;
592
593                 mp->minor = WD0_MINOR + i;
594                 mp->name = cpwd_names[i];
595                 mp->fops = &cpwd_fops;
596
597                 p->devs[i].regs = p->regs + (i * WD_TIMER_REGSZ);
598                 p->devs[i].intr_mask = (WD0_INTR_MASK << i);
599                 p->devs[i].runstatus &= ~WD_STAT_BSTOP;
600                 p->devs[i].runstatus |= WD_STAT_INIT;
601                 p->devs[i].timeout = p->timeout;
602                 if (*parms[i])
603                         p->devs[i].timeout = *parms[i];
604
605                 err = misc_register(&p->devs[i].misc);
606                 if (err) {
607                         printk(KERN_ERR "Could not register misc device for "
608                                "dev %d\n", i);
609                         goto out_unregister;
610                 }
611         }
612
613         if (p->broken) {
614                 init_timer(&cpwd_timer);
615                 cpwd_timer.function     = cpwd_brokentimer;
616                 cpwd_timer.data         = (unsigned long) p;
617                 cpwd_timer.expires      = WD_BTIMEOUT;
618
619                 printk(KERN_INFO PFX "PLD defect workaround enabled for "
620                        "model " WD_BADMODEL ".\n");
621         }
622
623         dev_set_drvdata(&op->dev, p);
624         cpwd_device = p;
625         err = 0;
626
627 out:
628         return err;
629
630 out_unregister:
631         for (i--; i >= 0; i--)
632                 misc_deregister(&p->devs[i].misc);
633
634 out_iounmap:
635         of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
636
637 out_free:
638         kfree(p);
639         goto out;
640 }
641
642 static int __devexit cpwd_remove(struct of_device *op)
643 {
644         struct cpwd *p = dev_get_drvdata(&op->dev);
645         int i;
646
647         for (i = 0; i < 4; i++) {
648                 misc_deregister(&p->devs[i].misc);
649
650                 if (!p->enabled) {
651                         cpwd_stoptimer(p, i);
652                         if (p->devs[i].runstatus & WD_STAT_BSTOP)
653                                 cpwd_resetbrokentimer(p, i);
654                 }
655         }
656
657         if (p->broken)
658                 del_timer_sync(&cpwd_timer);
659
660         if (p->initialized)
661                 free_irq(p->irq, p);
662
663         of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
664         kfree(p);
665
666         cpwd_device = NULL;
667
668         return 0;
669 }
670
671 static const struct of_device_id cpwd_match[] = {
672         {
673                 .name = "watchdog",
674         },
675         {},
676 };
677 MODULE_DEVICE_TABLE(of, cpwd_match);
678
679 static struct of_platform_driver cpwd_driver = {
680         .driver = {
681                 .name = DRIVER_NAME,
682                 .owner = THIS_MODULE,
683                 .of_match_table = cpwd_match,
684         },
685         .probe          = cpwd_probe,
686         .remove         = __devexit_p(cpwd_remove),
687 };
688
689 static int __init cpwd_init(void)
690 {
691         return of_register_platform_driver(&cpwd_driver);
692 }
693
694 static void __exit cpwd_exit(void)
695 {
696         of_unregister_platform_driver(&cpwd_driver);
697 }
698
699 module_init(cpwd_init);
700 module_exit(cpwd_exit);