xref: /linux/drivers/ptp/ptp_clock.c (revision a7ddedc84c59a645ef970b992f7cda5bffc70cc0) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * PTP 1588 clock support
4  *
5  * Copyright (C) 2010 OMICRON electronics GmbH
6  */
7 #include <linux/device.h>
8 #include <linux/err.h>
9 #include <linux/init.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/posix-clock.h>
13 #include <linux/pps_kernel.h>
14 #include <linux/property.h>
15 #include <linux/slab.h>
16 #include <linux/syscalls.h>
17 #include <linux/uaccess.h>
18 #include <linux/debugfs.h>
19 #include <linux/xarray.h>
20 #include <uapi/linux/sched/types.h>
21 
22 #include "ptp_private.h"
23 
24 #define PTP_MAX_ALARMS 4
25 #define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT)
26 #define PTP_PPS_EVENT PPS_CAPTUREASSERT
27 #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)
28 
29 const struct class ptp_class = {
30 	.name = "ptp",
31 	.dev_groups = ptp_groups
32 };
33 
34 /* private globals */
35 
36 static dev_t ptp_devt;
37 
38 static DEFINE_XARRAY_ALLOC(ptp_clocks_map);
39 
40 /* time stamp event queue operations */
41 
42 static inline int queue_free(struct timestamp_event_queue *q)
43 {
44 	return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
45 }
46 
47 static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
48 				       struct ptp_clock_event *src)
49 {
50 	struct ptp_extts_event *dst;
51 	struct timespec64 offset_ts;
52 	unsigned long flags;
53 	s64 seconds;
54 	u32 remainder;
55 
56 	if (src->type == PTP_CLOCK_EXTTS) {
57 		seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
58 	} else if (src->type == PTP_CLOCK_EXTOFF) {
59 		offset_ts = ns_to_timespec64(src->offset);
60 		seconds = offset_ts.tv_sec;
61 		remainder = offset_ts.tv_nsec;
62 	} else {
63 		WARN(1, "%s: unknown type %d\n", __func__, src->type);
64 		return;
65 	}
66 
67 	spin_lock_irqsave(&queue->lock, flags);
68 
69 	dst = &queue->buf[queue->tail];
70 	dst->index = src->index;
71 	dst->flags = PTP_EXTTS_EVENT_VALID;
72 	dst->t.sec = seconds;
73 	dst->t.nsec = remainder;
74 	if (src->type == PTP_CLOCK_EXTOFF)
75 		dst->flags |= PTP_EXT_OFFSET;
76 
77 	/* Both WRITE_ONCE() are paired with READ_ONCE() in queue_cnt() */
78 	if (!queue_free(queue))
79 		WRITE_ONCE(queue->head, (queue->head + 1) % PTP_MAX_TIMESTAMPS);
80 
81 	WRITE_ONCE(queue->tail, (queue->tail + 1) % PTP_MAX_TIMESTAMPS);
82 
83 	spin_unlock_irqrestore(&queue->lock, flags);
84 }
85 
86 /* posix clock implementation */
87 
88 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
89 {
90 	tp->tv_sec = 0;
91 	tp->tv_nsec = 1;
92 	return 0;
93 }
94 
95 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
96 {
97 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
98 
99 	if (ptp_clock_freerun(ptp)) {
100 		pr_err_ratelimited("ptp: physical clock is free running\n");
101 		return -EBUSY;
102 	}
103 
104 	if (!timespec64_valid_settod(tp))
105 		return -EINVAL;
106 
107 	return  ptp->info->settime64(ptp->info, tp);
108 }
109 
110 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
111 {
112 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
113 	int err;
114 
115 	if (ptp->info->gettimex64)
116 		err = ptp->info->gettimex64(ptp->info, tp, NULL);
117 	else
118 		err = ptp->info->gettime64(ptp->info, tp);
119 	return err;
120 }
121 
122 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
123 {
124 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
125 	struct ptp_clock_info *ops;
126 	int err = -EOPNOTSUPP;
127 
128 	if (tx->modes & (ADJ_SETOFFSET | ADJ_FREQUENCY | ADJ_OFFSET) &&
129 	    ptp_clock_freerun(ptp)) {
130 		pr_err("ptp: physical clock is free running\n");
131 		return -EBUSY;
132 	}
133 
134 	ops = ptp->info;
135 
136 	if (tx->modes & ADJ_SETOFFSET) {
137 		struct timespec64 ts, ts2;
138 		ktime_t kt;
139 		s64 delta;
140 
141 		ts.tv_sec  = tx->time.tv_sec;
142 		ts.tv_nsec = tx->time.tv_usec;
143 
144 		if (!(tx->modes & ADJ_NANO))
145 			ts.tv_nsec *= 1000;
146 
147 		if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
148 			return -EINVAL;
149 
150 		/* Make sure the offset is valid */
151 		err = ptp_clock_gettime(pc, &ts2);
152 		if (err)
153 			return err;
154 		ts2 = timespec64_add(ts2, ts);
155 		if (!timespec64_valid_settod(&ts2))
156 			return -EINVAL;
157 
158 		kt = timespec64_to_ktime(ts);
159 		delta = ktime_to_ns(kt);
160 		err = ops->adjtime(ops, delta);
161 	} else if (tx->modes & ADJ_FREQUENCY) {
162 		long ppb = scaled_ppm_to_ppb(tx->freq);
163 		if (ppb > ops->max_adj || ppb < -ops->max_adj)
164 			return -ERANGE;
165 		err = ops->adjfine(ops, tx->freq);
166 		if (!err)
167 			ptp->dialed_frequency = tx->freq;
168 	} else if (tx->modes & ADJ_OFFSET) {
169 		if (ops->adjphase) {
170 			s32 max_phase_adj = ops->getmaxphase(ops);
171 			s32 offset = tx->offset;
172 
173 			if (!(tx->modes & ADJ_NANO))
174 				offset *= NSEC_PER_USEC;
175 
176 			if (offset > max_phase_adj || offset < -max_phase_adj)
177 				return -ERANGE;
178 
179 			err = ops->adjphase(ops, offset);
180 		}
181 	} else if (tx->modes == 0) {
182 		tx->freq = ptp->dialed_frequency;
183 		err = 0;
184 	}
185 
186 	return err;
187 }
188 
189 static struct posix_clock_operations ptp_clock_ops = {
190 	.owner		= THIS_MODULE,
191 	.clock_adjtime	= ptp_clock_adjtime,
192 	.clock_gettime	= ptp_clock_gettime,
193 	.clock_getres	= ptp_clock_getres,
194 	.clock_settime	= ptp_clock_settime,
195 	.ioctl		= ptp_ioctl,
196 	.open		= ptp_open,
197 	.release	= ptp_release,
198 	.poll		= ptp_poll,
199 	.read		= ptp_read,
200 };
201 
202 static void ptp_clock_release(struct device *dev)
203 {
204 	struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
205 	struct timestamp_event_queue *tsevq;
206 	unsigned long flags;
207 
208 	ptp_cleanup_pin_groups(ptp);
209 	kfree(ptp->vclock_index);
210 	mutex_destroy(&ptp->pincfg_mux);
211 	mutex_destroy(&ptp->n_vclocks_mux);
212 	/* Delete first entry */
213 	spin_lock_irqsave(&ptp->tsevqs_lock, flags);
214 	tsevq = list_first_entry(&ptp->tsevqs, struct timestamp_event_queue,
215 				 qlist);
216 	list_del(&tsevq->qlist);
217 	spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
218 	bitmap_free(tsevq->mask);
219 	kfree(tsevq);
220 	debugfs_remove(ptp->debugfs_root);
221 	xa_erase(&ptp_clocks_map, ptp->index);
222 	kfree(ptp);
223 }
224 
225 static int ptp_getcycles64(struct ptp_clock_info *info, struct timespec64 *ts)
226 {
227 	if (info->getcyclesx64)
228 		return info->getcyclesx64(info, ts, NULL);
229 	else
230 		return info->gettime64(info, ts);
231 }
232 
233 static int ptp_enable(struct ptp_clock_info *ptp, struct ptp_clock_request *request, int on)
234 {
235 	return -EOPNOTSUPP;
236 }
237 
238 static void ptp_aux_kworker(struct kthread_work *work)
239 {
240 	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
241 					     aux_work.work);
242 	struct ptp_clock_info *info = ptp->info;
243 	long delay;
244 
245 	delay = info->do_aux_work(info);
246 
247 	if (delay >= 0)
248 		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
249 }
250 
251 /* public interface */
252 
253 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
254 				     struct device *parent)
255 {
256 	struct ptp_clock *ptp;
257 	struct timestamp_event_queue *queue = NULL;
258 	int err, index, major = MAJOR(ptp_devt);
259 	char debugfsname[16];
260 	size_t size;
261 
262 	if (info->n_alarm > PTP_MAX_ALARMS)
263 		return ERR_PTR(-EINVAL);
264 
265 	/* Initialize a clock structure. */
266 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
267 	if (!ptp) {
268 		err = -ENOMEM;
269 		goto no_memory;
270 	}
271 
272 	err = xa_alloc(&ptp_clocks_map, &index, ptp, xa_limit_31b,
273 		       GFP_KERNEL);
274 	if (err)
275 		goto no_slot;
276 
277 	ptp->clock.ops = ptp_clock_ops;
278 	ptp->info = info;
279 	ptp->devid = MKDEV(major, index);
280 	ptp->index = index;
281 	INIT_LIST_HEAD(&ptp->tsevqs);
282 	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
283 	if (!queue) {
284 		err = -ENOMEM;
285 		goto no_memory_queue;
286 	}
287 	list_add_tail(&queue->qlist, &ptp->tsevqs);
288 	spin_lock_init(&ptp->tsevqs_lock);
289 	queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL);
290 	if (!queue->mask) {
291 		err = -ENOMEM;
292 		goto no_memory_bitmap;
293 	}
294 	bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS);
295 	spin_lock_init(&queue->lock);
296 	mutex_init(&ptp->pincfg_mux);
297 	mutex_init(&ptp->n_vclocks_mux);
298 	init_waitqueue_head(&ptp->tsev_wq);
299 
300 	if (ptp->info->getcycles64 || ptp->info->getcyclesx64) {
301 		ptp->has_cycles = true;
302 		if (!ptp->info->getcycles64 && ptp->info->getcyclesx64)
303 			ptp->info->getcycles64 = ptp_getcycles64;
304 	} else {
305 		/* Free running cycle counter not supported, use time. */
306 		ptp->info->getcycles64 = ptp_getcycles64;
307 
308 		if (ptp->info->gettimex64)
309 			ptp->info->getcyclesx64 = ptp->info->gettimex64;
310 
311 		if (ptp->info->getcrosststamp)
312 			ptp->info->getcrosscycles = ptp->info->getcrosststamp;
313 	}
314 
315 	if (!ptp->info->enable)
316 		ptp->info->enable = ptp_enable;
317 
318 	if (ptp->info->do_aux_work) {
319 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
320 		ptp->kworker = kthread_run_worker(0, "ptp%d", ptp->index);
321 		if (IS_ERR(ptp->kworker)) {
322 			err = PTR_ERR(ptp->kworker);
323 			pr_err("failed to create ptp aux_worker %d\n", err);
324 			goto kworker_err;
325 		}
326 	}
327 
328 	/* PTP virtual clock is being registered under physical clock */
329 	if (parent && parent->class && parent->class->name &&
330 	    strcmp(parent->class->name, "ptp") == 0)
331 		ptp->is_virtual_clock = true;
332 
333 	if (!ptp->is_virtual_clock) {
334 		ptp->max_vclocks = PTP_DEFAULT_MAX_VCLOCKS;
335 
336 		size = sizeof(int) * ptp->max_vclocks;
337 		ptp->vclock_index = kzalloc(size, GFP_KERNEL);
338 		if (!ptp->vclock_index) {
339 			err = -ENOMEM;
340 			goto no_mem_for_vclocks;
341 		}
342 	}
343 
344 	err = ptp_populate_pin_groups(ptp);
345 	if (err)
346 		goto no_pin_groups;
347 
348 	/* Register a new PPS source. */
349 	if (info->pps) {
350 		struct pps_source_info pps;
351 		memset(&pps, 0, sizeof(pps));
352 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
353 		pps.mode = PTP_PPS_MODE;
354 		pps.owner = info->owner;
355 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
356 		if (IS_ERR(ptp->pps_source)) {
357 			err = PTR_ERR(ptp->pps_source);
358 			pr_err("failed to register pps source\n");
359 			goto no_pps;
360 		}
361 		ptp->pps_source->lookup_cookie = ptp;
362 	}
363 
364 	/* Initialize a new device of our class in our clock structure. */
365 	device_initialize(&ptp->dev);
366 	ptp->dev.devt = ptp->devid;
367 	ptp->dev.class = &ptp_class;
368 	ptp->dev.parent = parent;
369 	ptp->dev.groups = ptp->pin_attr_groups;
370 	ptp->dev.release = ptp_clock_release;
371 	dev_set_drvdata(&ptp->dev, ptp);
372 	dev_set_name(&ptp->dev, "ptp%d", ptp->index);
373 
374 	/* Create a posix clock and link it to the device. */
375 	err = posix_clock_register(&ptp->clock, &ptp->dev);
376 	if (err) {
377 		if (ptp->pps_source)
378 			pps_unregister_source(ptp->pps_source);
379 
380 		if (ptp->kworker)
381 			kthread_destroy_worker(ptp->kworker);
382 
383 		put_device(&ptp->dev);
384 
385 		pr_err("failed to create posix clock\n");
386 		return ERR_PTR(err);
387 	}
388 
389 	/* Debugfs initialization */
390 	snprintf(debugfsname, sizeof(debugfsname), "ptp%d", ptp->index);
391 	ptp->debugfs_root = debugfs_create_dir(debugfsname, NULL);
392 
393 	return ptp;
394 
395 no_pps:
396 	ptp_cleanup_pin_groups(ptp);
397 no_pin_groups:
398 	kfree(ptp->vclock_index);
399 no_mem_for_vclocks:
400 	if (ptp->kworker)
401 		kthread_destroy_worker(ptp->kworker);
402 kworker_err:
403 	mutex_destroy(&ptp->pincfg_mux);
404 	mutex_destroy(&ptp->n_vclocks_mux);
405 	bitmap_free(queue->mask);
406 no_memory_bitmap:
407 	list_del(&queue->qlist);
408 	kfree(queue);
409 no_memory_queue:
410 	xa_erase(&ptp_clocks_map, index);
411 no_slot:
412 	kfree(ptp);
413 no_memory:
414 	return ERR_PTR(err);
415 }
416 EXPORT_SYMBOL(ptp_clock_register);
417 
418 static int unregister_vclock(struct device *dev, void *data)
419 {
420 	struct ptp_clock *ptp = dev_get_drvdata(dev);
421 
422 	ptp_vclock_unregister(info_to_vclock(ptp->info));
423 	return 0;
424 }
425 
426 int ptp_clock_unregister(struct ptp_clock *ptp)
427 {
428 	if (ptp_vclock_in_use(ptp)) {
429 		device_for_each_child(&ptp->dev, NULL, unregister_vclock);
430 	}
431 
432 	ptp->defunct = 1;
433 	wake_up_interruptible(&ptp->tsev_wq);
434 
435 	if (ptp->kworker) {
436 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
437 		kthread_destroy_worker(ptp->kworker);
438 	}
439 
440 	/* Release the clock's resources. */
441 	if (ptp->pps_source)
442 		pps_unregister_source(ptp->pps_source);
443 
444 	posix_clock_unregister(&ptp->clock);
445 
446 	return 0;
447 }
448 EXPORT_SYMBOL(ptp_clock_unregister);
449 
450 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
451 {
452 	struct timestamp_event_queue *tsevq;
453 	struct pps_event_time evt;
454 	unsigned long flags;
455 
456 	switch (event->type) {
457 
458 	case PTP_CLOCK_ALARM:
459 		break;
460 
461 	case PTP_CLOCK_EXTTS:
462 	case PTP_CLOCK_EXTOFF:
463 		/* Enqueue timestamp on selected queues */
464 		spin_lock_irqsave(&ptp->tsevqs_lock, flags);
465 		list_for_each_entry(tsevq, &ptp->tsevqs, qlist) {
466 			if (test_bit((unsigned int)event->index, tsevq->mask))
467 				enqueue_external_timestamp(tsevq, event);
468 		}
469 		spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
470 		wake_up_interruptible(&ptp->tsev_wq);
471 		break;
472 
473 	case PTP_CLOCK_PPS:
474 		pps_get_ts(&evt);
475 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
476 		break;
477 
478 	case PTP_CLOCK_PPSUSR:
479 		pps_event(ptp->pps_source, &event->pps_times,
480 			  PTP_PPS_EVENT, NULL);
481 		break;
482 	}
483 }
484 EXPORT_SYMBOL(ptp_clock_event);
485 
486 int ptp_clock_index(struct ptp_clock *ptp)
487 {
488 	return ptp->index;
489 }
490 EXPORT_SYMBOL(ptp_clock_index);
491 
492 static int ptp_clock_of_node_match(struct device *dev, const void *data)
493 {
494 	const struct device_node *parent_np = data;
495 
496 	return (dev->parent && dev_of_node(dev->parent) == parent_np);
497 }
498 
499 int ptp_clock_index_by_of_node(struct device_node *np)
500 {
501 	struct ptp_clock *ptp;
502 	struct device *dev;
503 	int phc_index;
504 
505 	dev = class_find_device(&ptp_class, NULL, np,
506 				ptp_clock_of_node_match);
507 	if (!dev)
508 		return -1;
509 
510 	ptp = dev_get_drvdata(dev);
511 	phc_index = ptp_clock_index(ptp);
512 	put_device(dev);
513 
514 	return phc_index;
515 }
516 EXPORT_SYMBOL_GPL(ptp_clock_index_by_of_node);
517 
518 static int ptp_clock_dev_match(struct device *dev, const void *data)
519 {
520 	const struct device *parent = data;
521 
522 	return dev->parent == parent;
523 }
524 
525 int ptp_clock_index_by_dev(struct device *parent)
526 {
527 	struct ptp_clock *ptp;
528 	struct device *dev;
529 	int phc_index;
530 
531 	dev = class_find_device(&ptp_class, NULL, parent,
532 				ptp_clock_dev_match);
533 	if (!dev)
534 		return -1;
535 
536 	ptp = dev_get_drvdata(dev);
537 	phc_index = ptp_clock_index(ptp);
538 	put_device(dev);
539 
540 	return phc_index;
541 }
542 EXPORT_SYMBOL_GPL(ptp_clock_index_by_dev);
543 
544 int ptp_find_pin(struct ptp_clock *ptp,
545 		 enum ptp_pin_function func, unsigned int chan)
546 {
547 	struct ptp_pin_desc *pin = NULL;
548 	int i;
549 
550 	for (i = 0; i < ptp->info->n_pins; i++) {
551 		if (ptp->info->pin_config[i].func == func &&
552 		    ptp->info->pin_config[i].chan == chan) {
553 			pin = &ptp->info->pin_config[i];
554 			break;
555 		}
556 	}
557 
558 	return pin ? i : -1;
559 }
560 EXPORT_SYMBOL(ptp_find_pin);
561 
562 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
563 			  enum ptp_pin_function func, unsigned int chan)
564 {
565 	int result;
566 
567 	mutex_lock(&ptp->pincfg_mux);
568 
569 	result = ptp_find_pin(ptp, func, chan);
570 
571 	mutex_unlock(&ptp->pincfg_mux);
572 
573 	return result;
574 }
575 EXPORT_SYMBOL(ptp_find_pin_unlocked);
576 
577 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
578 {
579 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
580 }
581 EXPORT_SYMBOL(ptp_schedule_worker);
582 
583 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
584 {
585 	kthread_cancel_delayed_work_sync(&ptp->aux_work);
586 }
587 EXPORT_SYMBOL(ptp_cancel_worker_sync);
588 
589 /* module operations */
590 
591 static void __exit ptp_exit(void)
592 {
593 	class_unregister(&ptp_class);
594 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
595 	xa_destroy(&ptp_clocks_map);
596 }
597 
598 static int __init ptp_init(void)
599 {
600 	int err;
601 
602 	err = class_register(&ptp_class);
603 	if (err) {
604 		pr_err("ptp: failed to allocate class\n");
605 		return err;
606 	}
607 
608 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
609 	if (err < 0) {
610 		pr_err("ptp: failed to allocate device region\n");
611 		goto no_region;
612 	}
613 
614 	pr_info("PTP clock support registered\n");
615 	return 0;
616 
617 no_region:
618 	class_unregister(&ptp_class);
619 	return err;
620 }
621 
622 subsys_initcall(ptp_init);
623 module_exit(ptp_exit);
624 
625 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
626 MODULE_DESCRIPTION("PTP clocks support");
627 MODULE_LICENSE("GPL");
628