xref: /linux/drivers/ptp/ptp_clock.c (revision c85ae0240ee9ee9dfbd7e7fd8fc5f3c1c4367491) 
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/slab.h>
15 #include <linux/syscalls.h>
16 #include <linux/uaccess.h>
17 #include <linux/debugfs.h>
18 #include <linux/xarray.h>
19 #include <uapi/linux/sched/types.h>
20 
21 #include "ptp_private.h"
22 
23 #define PTP_MAX_ALARMS 4
24 #define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT)
25 #define PTP_PPS_EVENT PPS_CAPTUREASSERT
26 #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)
27 
28 const struct class ptp_class = {
29 	.name = "ptp",
30 	.dev_groups = ptp_groups
31 };
32 
33 /* private globals */
34 
35 static dev_t ptp_devt;
36 
37 static DEFINE_XARRAY_ALLOC(ptp_clocks_map);
38 
39 /* time stamp event queue operations */
40 
41 static inline int queue_free(struct timestamp_event_queue *q)
42 {
43 	return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
44 }
45 
46 static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
47 				       struct ptp_clock_event *src)
48 {
49 	struct ptp_extts_event *dst;
50 	struct timespec64 offset_ts;
51 	unsigned long flags;
52 	s64 seconds;
53 	u32 remainder;
54 
55 	if (src->type == PTP_CLOCK_EXTTS) {
56 		seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
57 	} else if (src->type == PTP_CLOCK_EXTOFF) {
58 		offset_ts = ns_to_timespec64(src->offset);
59 		seconds = offset_ts.tv_sec;
60 		remainder = offset_ts.tv_nsec;
61 	} else {
62 		WARN(1, "%s: unknown type %d\n", __func__, src->type);
63 		return;
64 	}
65 
66 	spin_lock_irqsave(&queue->lock, flags);
67 
68 	dst = &queue->buf[queue->tail];
69 	dst->index = src->index;
70 	dst->flags = PTP_EXTTS_EVENT_VALID;
71 	dst->t.sec = seconds;
72 	dst->t.nsec = remainder;
73 	if (src->type == PTP_CLOCK_EXTOFF)
74 		dst->flags |= PTP_EXT_OFFSET;
75 
76 	/* Both WRITE_ONCE() are paired with READ_ONCE() in queue_cnt() */
77 	if (!queue_free(queue))
78 		WRITE_ONCE(queue->head, (queue->head + 1) % PTP_MAX_TIMESTAMPS);
79 
80 	WRITE_ONCE(queue->tail, (queue->tail + 1) % PTP_MAX_TIMESTAMPS);
81 
82 	spin_unlock_irqrestore(&queue->lock, flags);
83 }
84 
85 /* posix clock implementation */
86 
87 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
88 {
89 	tp->tv_sec = 0;
90 	tp->tv_nsec = 1;
91 	return 0;
92 }
93 
94 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
95 {
96 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
97 
98 	if (ptp_clock_freerun(ptp)) {
99 		pr_err_ratelimited("ptp: physical clock is free running\n");
100 		return -EBUSY;
101 	}
102 
103 	if (!timespec64_valid_settod(tp))
104 		return -EINVAL;
105 
106 	return  ptp->info->settime64(ptp->info, tp);
107 }
108 
109 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
110 {
111 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
112 	int err;
113 
114 	if (ptp->info->gettimex64)
115 		err = ptp->info->gettimex64(ptp->info, tp, NULL);
116 	else
117 		err = ptp->info->gettime64(ptp->info, tp);
118 	return err;
119 }
120 
121 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
122 {
123 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
124 	struct ptp_clock_info *ops;
125 	int err = -EOPNOTSUPP;
126 
127 	if (tx->modes & (ADJ_SETOFFSET | ADJ_FREQUENCY | ADJ_OFFSET) &&
128 	    ptp_clock_freerun(ptp)) {
129 		pr_err("ptp: physical clock is free running\n");
130 		return -EBUSY;
131 	}
132 
133 	ops = ptp->info;
134 
135 	if (tx->modes & ADJ_SETOFFSET) {
136 		struct timespec64 ts, ts2;
137 		ktime_t kt;
138 		s64 delta;
139 
140 		ts.tv_sec  = tx->time.tv_sec;
141 		ts.tv_nsec = tx->time.tv_usec;
142 
143 		if (!(tx->modes & ADJ_NANO))
144 			ts.tv_nsec *= 1000;
145 
146 		if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
147 			return -EINVAL;
148 
149 		/* Make sure the offset is valid */
150 		err = ptp_clock_gettime(pc, &ts2);
151 		if (err)
152 			return err;
153 		ts2 = timespec64_add(ts2, ts);
154 		if (!timespec64_valid_settod(&ts2))
155 			return -EINVAL;
156 
157 		kt = timespec64_to_ktime(ts);
158 		delta = ktime_to_ns(kt);
159 		err = ops->adjtime(ops, delta);
160 	} else if (tx->modes & ADJ_FREQUENCY) {
161 		long ppb = scaled_ppm_to_ppb(tx->freq);
162 		if (ppb > ops->max_adj || ppb < -ops->max_adj)
163 			return -ERANGE;
164 		err = ops->adjfine(ops, tx->freq);
165 		if (!err)
166 			ptp->dialed_frequency = tx->freq;
167 	} else if (tx->modes & ADJ_OFFSET) {
168 		if (ops->adjphase) {
169 			s32 max_phase_adj = ops->getmaxphase(ops);
170 			s32 offset = tx->offset;
171 
172 			if (!(tx->modes & ADJ_NANO))
173 				offset *= NSEC_PER_USEC;
174 
175 			if (offset > max_phase_adj || offset < -max_phase_adj)
176 				return -ERANGE;
177 
178 			err = ops->adjphase(ops, offset);
179 		}
180 	} else if (tx->modes == 0) {
181 		tx->freq = ptp->dialed_frequency;
182 		err = 0;
183 	}
184 
185 	return err;
186 }
187 
188 static struct posix_clock_operations ptp_clock_ops = {
189 	.owner		= THIS_MODULE,
190 	.clock_adjtime	= ptp_clock_adjtime,
191 	.clock_gettime	= ptp_clock_gettime,
192 	.clock_getres	= ptp_clock_getres,
193 	.clock_settime	= ptp_clock_settime,
194 	.ioctl		= ptp_ioctl,
195 	.open		= ptp_open,
196 	.release	= ptp_release,
197 	.poll		= ptp_poll,
198 	.read		= ptp_read,
199 };
200 
201 static void ptp_clock_release(struct device *dev)
202 {
203 	struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
204 	struct timestamp_event_queue *tsevq;
205 	unsigned long flags;
206 
207 	ptp_cleanup_pin_groups(ptp);
208 	kfree(ptp->vclock_index);
209 	mutex_destroy(&ptp->pincfg_mux);
210 	mutex_destroy(&ptp->n_vclocks_mux);
211 	/* Delete first entry */
212 	spin_lock_irqsave(&ptp->tsevqs_lock, flags);
213 	tsevq = list_first_entry(&ptp->tsevqs, struct timestamp_event_queue,
214 				 qlist);
215 	list_del(&tsevq->qlist);
216 	spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
217 	bitmap_free(tsevq->mask);
218 	kfree(tsevq);
219 	debugfs_remove(ptp->debugfs_root);
220 	xa_erase(&ptp_clocks_map, ptp->index);
221 	kfree(ptp);
222 }
223 
224 static int ptp_getcycles64(struct ptp_clock_info *info, struct timespec64 *ts)
225 {
226 	if (info->getcyclesx64)
227 		return info->getcyclesx64(info, ts, NULL);
228 	else
229 		return info->gettime64(info, ts);
230 }
231 
232 static int ptp_enable(struct ptp_clock_info *ptp, struct ptp_clock_request *request, int on)
233 {
234 	return -EOPNOTSUPP;
235 }
236 
237 static void ptp_aux_kworker(struct kthread_work *work)
238 {
239 	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
240 					     aux_work.work);
241 	struct ptp_clock_info *info = ptp->info;
242 	long delay;
243 
244 	delay = info->do_aux_work(info);
245 
246 	if (delay >= 0)
247 		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
248 }
249 
250 /* public interface */
251 
252 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
253 				     struct device *parent)
254 {
255 	struct ptp_clock *ptp;
256 	struct timestamp_event_queue *queue = NULL;
257 	int err, index, major = MAJOR(ptp_devt);
258 	char debugfsname[16];
259 	size_t size;
260 
261 	if (info->n_alarm > PTP_MAX_ALARMS)
262 		return ERR_PTR(-EINVAL);
263 
264 	/* Initialize a clock structure. */
265 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
266 	if (!ptp) {
267 		err = -ENOMEM;
268 		goto no_memory;
269 	}
270 
271 	err = xa_alloc(&ptp_clocks_map, &index, ptp, xa_limit_31b,
272 		       GFP_KERNEL);
273 	if (err)
274 		goto no_slot;
275 
276 	ptp->clock.ops = ptp_clock_ops;
277 	ptp->info = info;
278 	ptp->devid = MKDEV(major, index);
279 	ptp->index = index;
280 	INIT_LIST_HEAD(&ptp->tsevqs);
281 	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
282 	if (!queue) {
283 		err = -ENOMEM;
284 		goto no_memory_queue;
285 	}
286 	list_add_tail(&queue->qlist, &ptp->tsevqs);
287 	spin_lock_init(&ptp->tsevqs_lock);
288 	queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL);
289 	if (!queue->mask) {
290 		err = -ENOMEM;
291 		goto no_memory_bitmap;
292 	}
293 	bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS);
294 	spin_lock_init(&queue->lock);
295 	mutex_init(&ptp->pincfg_mux);
296 	mutex_init(&ptp->n_vclocks_mux);
297 	init_waitqueue_head(&ptp->tsev_wq);
298 
299 	if (ptp->info->getcycles64 || ptp->info->getcyclesx64) {
300 		ptp->has_cycles = true;
301 		if (!ptp->info->getcycles64 && ptp->info->getcyclesx64)
302 			ptp->info->getcycles64 = ptp_getcycles64;
303 	} else {
304 		/* Free running cycle counter not supported, use time. */
305 		ptp->info->getcycles64 = ptp_getcycles64;
306 
307 		if (ptp->info->gettimex64)
308 			ptp->info->getcyclesx64 = ptp->info->gettimex64;
309 
310 		if (ptp->info->getcrosststamp)
311 			ptp->info->getcrosscycles = ptp->info->getcrosststamp;
312 	}
313 
314 	if (!ptp->info->enable)
315 		ptp->info->enable = ptp_enable;
316 
317 	if (ptp->info->do_aux_work) {
318 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
319 		ptp->kworker = kthread_run_worker(0, "ptp%d", ptp->index);
320 		if (IS_ERR(ptp->kworker)) {
321 			err = PTR_ERR(ptp->kworker);
322 			pr_err("failed to create ptp aux_worker %d\n", err);
323 			goto kworker_err;
324 		}
325 	}
326 
327 	/* PTP virtual clock is being registered under physical clock */
328 	if (parent && parent->class && parent->class->name &&
329 	    strcmp(parent->class->name, "ptp") == 0)
330 		ptp->is_virtual_clock = true;
331 
332 	if (!ptp->is_virtual_clock) {
333 		ptp->max_vclocks = PTP_DEFAULT_MAX_VCLOCKS;
334 
335 		size = sizeof(int) * ptp->max_vclocks;
336 		ptp->vclock_index = kzalloc(size, GFP_KERNEL);
337 		if (!ptp->vclock_index) {
338 			err = -ENOMEM;
339 			goto no_mem_for_vclocks;
340 		}
341 	}
342 
343 	err = ptp_populate_pin_groups(ptp);
344 	if (err)
345 		goto no_pin_groups;
346 
347 	/* Register a new PPS source. */
348 	if (info->pps) {
349 		struct pps_source_info pps;
350 		memset(&pps, 0, sizeof(pps));
351 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
352 		pps.mode = PTP_PPS_MODE;
353 		pps.owner = info->owner;
354 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
355 		if (IS_ERR(ptp->pps_source)) {
356 			err = PTR_ERR(ptp->pps_source);
357 			pr_err("failed to register pps source\n");
358 			goto no_pps;
359 		}
360 		ptp->pps_source->lookup_cookie = ptp;
361 	}
362 
363 	/* Initialize a new device of our class in our clock structure. */
364 	device_initialize(&ptp->dev);
365 	ptp->dev.devt = ptp->devid;
366 	ptp->dev.class = &ptp_class;
367 	ptp->dev.parent = parent;
368 	ptp->dev.groups = ptp->pin_attr_groups;
369 	ptp->dev.release = ptp_clock_release;
370 	dev_set_drvdata(&ptp->dev, ptp);
371 	dev_set_name(&ptp->dev, "ptp%d", ptp->index);
372 
373 	/* Create a posix clock and link it to the device. */
374 	err = posix_clock_register(&ptp->clock, &ptp->dev);
375 	if (err) {
376 		if (ptp->pps_source)
377 			pps_unregister_source(ptp->pps_source);
378 
379 		if (ptp->kworker)
380 			kthread_destroy_worker(ptp->kworker);
381 
382 		put_device(&ptp->dev);
383 
384 		pr_err("failed to create posix clock\n");
385 		return ERR_PTR(err);
386 	}
387 
388 	/* Debugfs initialization */
389 	snprintf(debugfsname, sizeof(debugfsname), "ptp%d", ptp->index);
390 	ptp->debugfs_root = debugfs_create_dir(debugfsname, NULL);
391 
392 	return ptp;
393 
394 no_pps:
395 	ptp_cleanup_pin_groups(ptp);
396 no_pin_groups:
397 	kfree(ptp->vclock_index);
398 no_mem_for_vclocks:
399 	if (ptp->kworker)
400 		kthread_destroy_worker(ptp->kworker);
401 kworker_err:
402 	mutex_destroy(&ptp->pincfg_mux);
403 	mutex_destroy(&ptp->n_vclocks_mux);
404 	bitmap_free(queue->mask);
405 no_memory_bitmap:
406 	list_del(&queue->qlist);
407 	kfree(queue);
408 no_memory_queue:
409 	xa_erase(&ptp_clocks_map, index);
410 no_slot:
411 	kfree(ptp);
412 no_memory:
413 	return ERR_PTR(err);
414 }
415 EXPORT_SYMBOL(ptp_clock_register);
416 
417 static int unregister_vclock(struct device *dev, void *data)
418 {
419 	struct ptp_clock *ptp = dev_get_drvdata(dev);
420 
421 	ptp_vclock_unregister(info_to_vclock(ptp->info));
422 	return 0;
423 }
424 
425 int ptp_clock_unregister(struct ptp_clock *ptp)
426 {
427 	if (ptp_vclock_in_use(ptp)) {
428 		device_for_each_child(&ptp->dev, NULL, unregister_vclock);
429 	}
430 
431 	ptp->defunct = 1;
432 	wake_up_interruptible(&ptp->tsev_wq);
433 
434 	if (ptp->kworker) {
435 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
436 		kthread_destroy_worker(ptp->kworker);
437 	}
438 
439 	/* Release the clock's resources. */
440 	if (ptp->pps_source)
441 		pps_unregister_source(ptp->pps_source);
442 
443 	posix_clock_unregister(&ptp->clock);
444 
445 	return 0;
446 }
447 EXPORT_SYMBOL(ptp_clock_unregister);
448 
449 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
450 {
451 	struct timestamp_event_queue *tsevq;
452 	struct pps_event_time evt;
453 	unsigned long flags;
454 
455 	switch (event->type) {
456 
457 	case PTP_CLOCK_ALARM:
458 		break;
459 
460 	case PTP_CLOCK_EXTTS:
461 	case PTP_CLOCK_EXTOFF:
462 		/* Enqueue timestamp on selected queues */
463 		spin_lock_irqsave(&ptp->tsevqs_lock, flags);
464 		list_for_each_entry(tsevq, &ptp->tsevqs, qlist) {
465 			if (test_bit((unsigned int)event->index, tsevq->mask))
466 				enqueue_external_timestamp(tsevq, event);
467 		}
468 		spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
469 		wake_up_interruptible(&ptp->tsev_wq);
470 		break;
471 
472 	case PTP_CLOCK_PPS:
473 		pps_get_ts(&evt);
474 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
475 		break;
476 
477 	case PTP_CLOCK_PPSUSR:
478 		pps_event(ptp->pps_source, &event->pps_times,
479 			  PTP_PPS_EVENT, NULL);
480 		break;
481 	}
482 }
483 EXPORT_SYMBOL(ptp_clock_event);
484 
485 int ptp_clock_index(struct ptp_clock *ptp)
486 {
487 	return ptp->index;
488 }
489 EXPORT_SYMBOL(ptp_clock_index);
490 
491 int ptp_find_pin(struct ptp_clock *ptp,
492 		 enum ptp_pin_function func, unsigned int chan)
493 {
494 	struct ptp_pin_desc *pin = NULL;
495 	int i;
496 
497 	for (i = 0; i < ptp->info->n_pins; i++) {
498 		if (ptp->info->pin_config[i].func == func &&
499 		    ptp->info->pin_config[i].chan == chan) {
500 			pin = &ptp->info->pin_config[i];
501 			break;
502 		}
503 	}
504 
505 	return pin ? i : -1;
506 }
507 EXPORT_SYMBOL(ptp_find_pin);
508 
509 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
510 			  enum ptp_pin_function func, unsigned int chan)
511 {
512 	int result;
513 
514 	mutex_lock(&ptp->pincfg_mux);
515 
516 	result = ptp_find_pin(ptp, func, chan);
517 
518 	mutex_unlock(&ptp->pincfg_mux);
519 
520 	return result;
521 }
522 EXPORT_SYMBOL(ptp_find_pin_unlocked);
523 
524 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
525 {
526 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
527 }
528 EXPORT_SYMBOL(ptp_schedule_worker);
529 
530 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
531 {
532 	kthread_cancel_delayed_work_sync(&ptp->aux_work);
533 }
534 EXPORT_SYMBOL(ptp_cancel_worker_sync);
535 
536 /* module operations */
537 
538 static void __exit ptp_exit(void)
539 {
540 	class_unregister(&ptp_class);
541 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
542 	xa_destroy(&ptp_clocks_map);
543 }
544 
545 static int __init ptp_init(void)
546 {
547 	int err;
548 
549 	err = class_register(&ptp_class);
550 	if (err) {
551 		pr_err("ptp: failed to allocate class\n");
552 		return err;
553 	}
554 
555 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
556 	if (err < 0) {
557 		pr_err("ptp: failed to allocate device region\n");
558 		goto no_region;
559 	}
560 
561 	pr_info("PTP clock support registered\n");
562 	return 0;
563 
564 no_region:
565 	class_unregister(&ptp_class);
566 	return err;
567 }
568 
569 subsys_initcall(ptp_init);
570 module_exit(ptp_exit);
571 
572 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
573 MODULE_DESCRIPTION("PTP clocks support");
574 MODULE_LICENSE("GPL");
575