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Linux 4.19.133
[linux/fpc-iii.git] / drivers / watchdog / cpwd.c
blobaee0b25cf10d9afd48604b943fa17d97a6fe6927
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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/fs.h>
22 #include <linux/errno.h>
23 #include <linux/major.h>
24 #include <linux/miscdevice.h>
25 #include <linux/interrupt.h>
26 #include <linux/ioport.h>
27 #include <linux/timer.h>
28 #include <linux/slab.h>
29 #include <linux/mutex.h>
30 #include <linux/io.h>
31 #include <linux/of.h>
32 #include <linux/of_device.h>
33 #include <linux/uaccess.h>
34
35 #include <asm/irq.h>
36 #include <asm/watchdog.h>
37
38 #define DRIVER_NAME "cpwd"
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 DEFINE_MUTEX(cpwd_mutex);
93 static struct cpwd *cpwd_device;
94
95 /* Sun uses Altera PLD EPF8820ATC144-4
96 * providing three hardware watchdogs:
97 *
98 * 1) RIC - sends an interrupt when triggered
99 * 2) XIR - asserts XIR_B_RESET when triggered, resets CPU
100 * 3) POR - asserts POR_B_RESET when triggered, resets CPU, backplane, board
101 *
102 *** Timer register block definition (struct wd_timer_regblk)
103 *
104 * dcntr and limit registers (halfword access):
105 * -------------------
106 * | 15 | ...| 1 | 0 |
107 * -------------------
108 * |- counter val -|
109 * -------------------
110 * dcntr - Current 16-bit downcounter value.
111 * When downcounter reaches '0' watchdog expires.
112 * Reading this register resets downcounter with
113 * 'limit' value.
114 * limit - 16-bit countdown value in 1/10th second increments.
115 * Writing this register begins countdown with input value.
116 * Reading from this register does not affect counter.
117 * NOTES: After watchdog reset, dcntr and limit contain '1'
118 *
119 * status register (byte access):
120 * ---------------------------
121 * | 7 | ... | 2 | 1 | 0 |
122 * --------------+------------
123 * |- UNUSED -| EXP | RUN |
124 * ---------------------------
125 * status- Bit 0 - Watchdog is running
126 * Bit 1 - Watchdog has expired
127 *
128 *** PLD register block definition (struct wd_pld_regblk)
129 *
130 * intr_mask register (byte access):
131 * ---------------------------------
132 * | 7 | ... | 3 | 2 | 1 | 0 |
133 * +-------------+------------------
134 * |- UNUSED -| WD3 | WD2 | WD1 |
135 * ---------------------------------
136 * WD3 - 1 == Interrupt disabled for watchdog 3
137 * WD2 - 1 == Interrupt disabled for watchdog 2
138 * WD1 - 1 == Interrupt disabled for watchdog 1
139 *
140 * pld_status register (byte access):
141 * UNKNOWN, MAGICAL MYSTERY REGISTER
142 *
143 */
144 #define WD_TIMER_REGSZ 16
145 #define WD0_OFF 0
146 #define WD1_OFF (WD_TIMER_REGSZ * 1)
147 #define WD2_OFF (WD_TIMER_REGSZ * 2)
148 #define PLD_OFF (WD_TIMER_REGSZ * 3)
149
150 #define WD_DCNTR 0x00
151 #define WD_LIMIT 0x04
152 #define WD_STATUS 0x08
153
154 #define PLD_IMASK (PLD_OFF + 0x00)
155 #define PLD_STATUS (PLD_OFF + 0x04)
156
157 static struct timer_list cpwd_timer;
158
159 static int wd0_timeout;
160 static int wd1_timeout;
161 static int wd2_timeout;
162
163 module_param(wd0_timeout, int, 0);
164 MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs");
165 module_param(wd1_timeout, int, 0);
166 MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs");
167 module_param(wd2_timeout, int, 0);
168 MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs");
169
170 MODULE_AUTHOR("Eric Brower <ebrower@usa.net>");
171 MODULE_DESCRIPTION("Hardware watchdog driver for Sun Microsystems CP1400/1500");
172 MODULE_LICENSE("GPL");
173 MODULE_SUPPORTED_DEVICE("watchdog");
174
175 static void cpwd_writew(u16 val, void __iomem *addr)
176 {
177 writew(cpu_to_le16(val), addr);
178 }
179 static u16 cpwd_readw(void __iomem *addr)
180 {
181 u16 val = readw(addr);
182
183 return le16_to_cpu(val);
184 }
185
186 static void cpwd_writeb(u8 val, void __iomem *addr)
187 {
188 writeb(val, addr);
189 }
190
191 static u8 cpwd_readb(void __iomem *addr)
192 {
193 return readb(addr);
194 }
195
196 /* Enable or disable watchdog interrupts
197 * Because of the CP1400 defect this should only be
198 * called during initialzation or by wd_[start|stop]timer()
199 *
200 * index - sub-device index, or -1 for 'all'
201 * enable - non-zero to enable interrupts, zero to disable
202 */
203 static void cpwd_toggleintr(struct cpwd *p, int index, int enable)
204 {
205 unsigned char curregs = cpwd_readb(p->regs + PLD_IMASK);
206 unsigned char setregs =
207 (index == -1) ?
208 (WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) :
209 (p->devs[index].intr_mask);
210
211 if (enable == WD_INTR_ON)
212 curregs &= ~setregs;
213 else
214 curregs |= setregs;
215
216 cpwd_writeb(curregs, p->regs + PLD_IMASK);
217 }
218
219 /* Restarts timer with maximum limit value and
220 * does not unset 'brokenstop' value.
221 */
222 static void cpwd_resetbrokentimer(struct cpwd *p, int index)
223 {
224 cpwd_toggleintr(p, index, WD_INTR_ON);
225 cpwd_writew(WD_BLIMIT, p->devs[index].regs + WD_LIMIT);
226 }
227
228 /* Timer method called to reset stopped watchdogs--
229 * because of the PLD bug on CP1400, we cannot mask
230 * interrupts within the PLD so me must continually
231 * reset the timers ad infinitum.
232 */
233 static void cpwd_brokentimer(struct timer_list *unused)
234 {
235 struct cpwd *p = cpwd_device;
236 int id, tripped = 0;
237
238 /* kill a running timer instance, in case we
239 * were called directly instead of by kernel timer
240 */
241 if (timer_pending(&cpwd_timer))
242 del_timer(&cpwd_timer);
243
244 for (id = 0; id < WD_NUMDEVS; id++) {
245 if (p->devs[id].runstatus & WD_STAT_BSTOP) {
246 ++tripped;
247 cpwd_resetbrokentimer(p, id);
248 }
249 }
250
251 if (tripped) {
252 /* there is at least one timer brokenstopped-- reschedule */
253 cpwd_timer.expires = WD_BTIMEOUT;
254 add_timer(&cpwd_timer);
255 }
256 }
257
258 /* Reset countdown timer with 'limit' value and continue countdown.
259 * This will not start a stopped timer.
260 */
261 static void cpwd_pingtimer(struct cpwd *p, int index)
262 {
263 if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING)
264 cpwd_readw(p->devs[index].regs + WD_DCNTR);
265 }
266
267 /* Stop a running watchdog timer-- the timer actually keeps
268 * running, but the interrupt is masked so that no action is
269 * taken upon expiration.
270 */
271 static void cpwd_stoptimer(struct cpwd *p, int index)
272 {
273 if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING) {
274 cpwd_toggleintr(p, index, WD_INTR_OFF);
275
276 if (p->broken) {
277 p->devs[index].runstatus |= WD_STAT_BSTOP;
278 cpwd_brokentimer(NULL);
279 }
280 }
281 }
282
283 /* Start a watchdog timer with the specified limit value
284 * If the watchdog is running, it will be restarted with
285 * the provided limit value.
286 *
287 * This function will enable interrupts on the specified
288 * watchdog.
289 */
290 static void cpwd_starttimer(struct cpwd *p, int index)
291 {
292 if (p->broken)
293 p->devs[index].runstatus &= ~WD_STAT_BSTOP;
294
295 p->devs[index].runstatus &= ~WD_STAT_SVCD;
296
297 cpwd_writew(p->devs[index].timeout, p->devs[index].regs + WD_LIMIT);
298 cpwd_toggleintr(p, index, WD_INTR_ON);
299 }
300
301 static int cpwd_getstatus(struct cpwd *p, int index)
302 {
303 unsigned char stat = cpwd_readb(p->devs[index].regs + WD_STATUS);
304 unsigned char intr = cpwd_readb(p->devs[index].regs + PLD_IMASK);
305 unsigned char ret = WD_STOPPED;
306
307 /* determine STOPPED */
308 if (!stat)
309 return ret;
310
311 /* determine EXPIRED vs FREERUN vs RUNNING */
312 else if (WD_S_EXPIRED & stat) {
313 ret = WD_EXPIRED;
314 } else if (WD_S_RUNNING & stat) {
315 if (intr & p->devs[index].intr_mask) {
316 ret = WD_FREERUN;
317 } else {
318 /* Fudge WD_EXPIRED status for defective CP1400--
319 * IF timer is running
320 * AND brokenstop is set
321 * AND an interrupt has been serviced
322 * we are WD_EXPIRED.
323 *
324 * IF timer is running
325 * AND brokenstop is set
326 * AND no interrupt has been serviced
327 * we are WD_FREERUN.
328 */
329 if (p->broken &&
330 (p->devs[index].runstatus & WD_STAT_BSTOP)) {
331 if (p->devs[index].runstatus & WD_STAT_SVCD) {
332 ret = WD_EXPIRED;
333 } else {
334 /* we could as well pretend
335 * we are expired */
336 ret = WD_FREERUN;
337 }
338 } else {
339 ret = WD_RUNNING;
340 }
341 }
342 }
343
344 /* determine SERVICED */
345 if (p->devs[index].runstatus & WD_STAT_SVCD)
346 ret |= WD_SERVICED;
347
348 return ret;
349 }
350
351 static irqreturn_t cpwd_interrupt(int irq, void *dev_id)
352 {
353 struct cpwd *p = dev_id;
354
355 /* Only WD0 will interrupt-- others are NMI and we won't
356 * see them here....
357 */
358 spin_lock_irq(&p->lock);
359
360 cpwd_stoptimer(p, WD0_ID);
361 p->devs[WD0_ID].runstatus |= WD_STAT_SVCD;
362
363 spin_unlock_irq(&p->lock);
364
365 return IRQ_HANDLED;
366 }
367
368 static int cpwd_open(struct inode *inode, struct file *f)
369 {
370 struct cpwd *p = cpwd_device;
371
372 mutex_lock(&cpwd_mutex);
373 switch (iminor(inode)) {
374 case WD0_MINOR:
375 case WD1_MINOR:
376 case WD2_MINOR:
377 break;
378
379 default:
380 mutex_unlock(&cpwd_mutex);
381 return -ENODEV;
382 }
383
384 /* Register IRQ on first open of device */
385 if (!p->initialized) {
386 if (request_irq(p->irq, &cpwd_interrupt,
387 IRQF_SHARED, DRIVER_NAME, p)) {
388 pr_err("Cannot register IRQ %d\n", p->irq);
389 mutex_unlock(&cpwd_mutex);
390 return -EBUSY;
391 }
392 p->initialized = true;
393 }
394
395 mutex_unlock(&cpwd_mutex);
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_inode(file);
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 mutex_lock(&cpwd_mutex);
486 rval = cpwd_ioctl(file, cmd, arg);
487 mutex_unlock(&cpwd_mutex);
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_inode(file);
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 .llseek = no_llseek,
528 };
529
530 static int cpwd_probe(struct platform_device *op)
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 = devm_kzalloc(&op->dev, sizeof(*p), GFP_KERNEL);
542 if (!p)
543 return -ENOMEM;
544
545 p->irq = op->archdata.irqs[0];
546
547 spin_lock_init(&p->lock);
548
549 p->regs = of_ioremap(&op->resource[0], 0,
550 4 * WD_TIMER_REGSZ, DRIVER_NAME);
551 if (!p->regs) {
552 pr_err("Unable to map registers\n");
553 return -ENOMEM;
554 }
555
556 options = of_find_node_by_path("/options");
557 if (!options) {
558 err = -ENODEV;
559 pr_err("Unable to find /options node\n");
560 goto out_iounmap;
561 }
562
563 prop_val = of_get_property(options, "watchdog-enable?", NULL);
564 p->enabled = (prop_val ? true : false);
565
566 prop_val = of_get_property(options, "watchdog-reboot?", NULL);
567 p->reboot = (prop_val ? true : false);
568
569 str_prop = of_get_property(options, "watchdog-timeout", NULL);
570 if (str_prop)
571 p->timeout = simple_strtoul(str_prop, NULL, 10);
572
573 /* CP1400s seem to have broken PLD implementations-- the
574 * interrupt_mask register cannot be written, so no timer
575 * interrupts can be masked within the PLD.
576 */
577 str_prop = of_get_property(op->dev.of_node, "model", NULL);
578 p->broken = (str_prop && !strcmp(str_prop, WD_BADMODEL));
579
580 if (!p->enabled)
581 cpwd_toggleintr(p, -1, WD_INTR_OFF);
582
583 for (i = 0; i < WD_NUMDEVS; i++) {
584 static const char *cpwd_names[] = { "RIC", "XIR", "POR" };
585 static int *parms[] = { &wd0_timeout,
586 &wd1_timeout,
587 &wd2_timeout };
588 struct miscdevice *mp = &p->devs[i].misc;
589
590 mp->minor = WD0_MINOR + i;
591 mp->name = cpwd_names[i];
592 mp->fops = &cpwd_fops;
593
594 p->devs[i].regs = p->regs + (i * WD_TIMER_REGSZ);
595 p->devs[i].intr_mask = (WD0_INTR_MASK << i);
596 p->devs[i].runstatus &= ~WD_STAT_BSTOP;
597 p->devs[i].runstatus |= WD_STAT_INIT;
598 p->devs[i].timeout = p->timeout;
599 if (*parms[i])
600 p->devs[i].timeout = *parms[i];
601
602 err = misc_register(&p->devs[i].misc);
603 if (err) {
604 pr_err("Could not register misc device for dev %d\n",
605 i);
606 goto out_unregister;
607 }
608 }
609
610 if (p->broken) {
611 timer_setup(&cpwd_timer, cpwd_brokentimer, 0);
612 cpwd_timer.expires = WD_BTIMEOUT;
613
614 pr_info("PLD defect workaround enabled for model %s\n",
615 WD_BADMODEL);
616 }
617
618 platform_set_drvdata(op, p);
619 cpwd_device = p;
620 return 0;
621
622 out_unregister:
623 for (i--; i >= 0; i--)
624 misc_deregister(&p->devs[i].misc);
625
626 out_iounmap:
627 of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
628
629 return err;
630 }
631
632 static int cpwd_remove(struct platform_device *op)
633 {
634 struct cpwd *p = platform_get_drvdata(op);
635 int i;
636
637 for (i = 0; i < WD_NUMDEVS; i++) {
638 misc_deregister(&p->devs[i].misc);
639
640 if (!p->enabled) {
641 cpwd_stoptimer(p, i);
642 if (p->devs[i].runstatus & WD_STAT_BSTOP)
643 cpwd_resetbrokentimer(p, i);
644 }
645 }
646
647 if (p->broken)
648 del_timer_sync(&cpwd_timer);
649
650 if (p->initialized)
651 free_irq(p->irq, p);
652
653 of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
654
655 cpwd_device = NULL;
656
657 return 0;
658 }
659
660 static const struct of_device_id cpwd_match[] = {
661 {
662 .name = "watchdog",
663 },
664 {},
665 };
666 MODULE_DEVICE_TABLE(of, cpwd_match);
667
668 static struct platform_driver cpwd_driver = {
669 .driver = {
670 .name = DRIVER_NAME,
671 .of_match_table = cpwd_match,
672 },
673 .probe = cpwd_probe,
674 .remove = cpwd_remove,
675 };
676
677 module_platform_driver(cpwd_driver);
Linux with added FPC-III support