xref: /linux/drivers/ptp/ptp_clock.c (revision c2933b2befe25309f4c5cfbea0ca80909735fd76) 
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("ptp: physical clock is free running\n");
100 		return -EBUSY;
101 	}
102 
103 	return  ptp->info->settime64(ptp->info, tp);
104 }
105 
106 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
107 {
108 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
109 	int err;
110 
111 	if (ptp->info->gettimex64)
112 		err = ptp->info->gettimex64(ptp->info, tp, NULL);
113 	else
114 		err = ptp->info->gettime64(ptp->info, tp);
115 	return err;
116 }
117 
118 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
119 {
120 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
121 	struct ptp_clock_info *ops;
122 	int err = -EOPNOTSUPP;
123 
124 	if (ptp_clock_freerun(ptp)) {
125 		pr_err("ptp: physical clock is free running\n");
126 		return -EBUSY;
127 	}
128 
129 	ops = ptp->info;
130 
131 	if (tx->modes & ADJ_SETOFFSET) {
132 		struct timespec64 ts;
133 		ktime_t kt;
134 		s64 delta;
135 
136 		ts.tv_sec  = tx->time.tv_sec;
137 		ts.tv_nsec = tx->time.tv_usec;
138 
139 		if (!(tx->modes & ADJ_NANO))
140 			ts.tv_nsec *= 1000;
141 
142 		if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
143 			return -EINVAL;
144 
145 		kt = timespec64_to_ktime(ts);
146 		delta = ktime_to_ns(kt);
147 		err = ops->adjtime(ops, delta);
148 	} else if (tx->modes & ADJ_FREQUENCY) {
149 		long ppb = scaled_ppm_to_ppb(tx->freq);
150 		if (ppb > ops->max_adj || ppb < -ops->max_adj)
151 			return -ERANGE;
152 		err = ops->adjfine(ops, tx->freq);
153 		if (!err)
154 			ptp->dialed_frequency = tx->freq;
155 	} else if (tx->modes & ADJ_OFFSET) {
156 		if (ops->adjphase) {
157 			s32 max_phase_adj = ops->getmaxphase(ops);
158 			s32 offset = tx->offset;
159 
160 			if (!(tx->modes & ADJ_NANO))
161 				offset *= NSEC_PER_USEC;
162 
163 			if (offset > max_phase_adj || offset < -max_phase_adj)
164 				return -ERANGE;
165 
166 			err = ops->adjphase(ops, offset);
167 		}
168 	} else if (tx->modes == 0) {
169 		tx->freq = ptp->dialed_frequency;
170 		err = 0;
171 	}
172 
173 	return err;
174 }
175 
176 static struct posix_clock_operations ptp_clock_ops = {
177 	.owner		= THIS_MODULE,
178 	.clock_adjtime	= ptp_clock_adjtime,
179 	.clock_gettime	= ptp_clock_gettime,
180 	.clock_getres	= ptp_clock_getres,
181 	.clock_settime	= ptp_clock_settime,
182 	.ioctl		= ptp_ioctl,
183 	.open		= ptp_open,
184 	.release	= ptp_release,
185 	.poll		= ptp_poll,
186 	.read		= ptp_read,
187 };
188 
189 static void ptp_clock_release(struct device *dev)
190 {
191 	struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
192 	struct timestamp_event_queue *tsevq;
193 	unsigned long flags;
194 
195 	ptp_cleanup_pin_groups(ptp);
196 	kfree(ptp->vclock_index);
197 	mutex_destroy(&ptp->pincfg_mux);
198 	mutex_destroy(&ptp->n_vclocks_mux);
199 	/* Delete first entry */
200 	spin_lock_irqsave(&ptp->tsevqs_lock, flags);
201 	tsevq = list_first_entry(&ptp->tsevqs, struct timestamp_event_queue,
202 				 qlist);
203 	list_del(&tsevq->qlist);
204 	spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
205 	bitmap_free(tsevq->mask);
206 	kfree(tsevq);
207 	debugfs_remove(ptp->debugfs_root);
208 	xa_erase(&ptp_clocks_map, ptp->index);
209 	kfree(ptp);
210 }
211 
212 static int ptp_getcycles64(struct ptp_clock_info *info, struct timespec64 *ts)
213 {
214 	if (info->getcyclesx64)
215 		return info->getcyclesx64(info, ts, NULL);
216 	else
217 		return info->gettime64(info, ts);
218 }
219 
220 static int ptp_enable(struct ptp_clock_info *ptp, struct ptp_clock_request *request, int on)
221 {
222 	return -EOPNOTSUPP;
223 }
224 
225 static void ptp_aux_kworker(struct kthread_work *work)
226 {
227 	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
228 					     aux_work.work);
229 	struct ptp_clock_info *info = ptp->info;
230 	long delay;
231 
232 	delay = info->do_aux_work(info);
233 
234 	if (delay >= 0)
235 		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
236 }
237 
238 /* public interface */
239 
240 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
241 				     struct device *parent)
242 {
243 	struct ptp_clock *ptp;
244 	struct timestamp_event_queue *queue = NULL;
245 	int err, index, major = MAJOR(ptp_devt);
246 	char debugfsname[16];
247 	size_t size;
248 
249 	if (info->n_alarm > PTP_MAX_ALARMS)
250 		return ERR_PTR(-EINVAL);
251 
252 	/* Initialize a clock structure. */
253 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
254 	if (!ptp) {
255 		err = -ENOMEM;
256 		goto no_memory;
257 	}
258 
259 	err = xa_alloc(&ptp_clocks_map, &index, ptp, xa_limit_31b,
260 		       GFP_KERNEL);
261 	if (err)
262 		goto no_slot;
263 
264 	ptp->clock.ops = ptp_clock_ops;
265 	ptp->info = info;
266 	ptp->devid = MKDEV(major, index);
267 	ptp->index = index;
268 	INIT_LIST_HEAD(&ptp->tsevqs);
269 	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
270 	if (!queue) {
271 		err = -ENOMEM;
272 		goto no_memory_queue;
273 	}
274 	list_add_tail(&queue->qlist, &ptp->tsevqs);
275 	spin_lock_init(&ptp->tsevqs_lock);
276 	queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL);
277 	if (!queue->mask) {
278 		err = -ENOMEM;
279 		goto no_memory_bitmap;
280 	}
281 	bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS);
282 	spin_lock_init(&queue->lock);
283 	mutex_init(&ptp->pincfg_mux);
284 	mutex_init(&ptp->n_vclocks_mux);
285 	init_waitqueue_head(&ptp->tsev_wq);
286 
287 	if (ptp->info->getcycles64 || ptp->info->getcyclesx64) {
288 		ptp->has_cycles = true;
289 		if (!ptp->info->getcycles64 && ptp->info->getcyclesx64)
290 			ptp->info->getcycles64 = ptp_getcycles64;
291 	} else {
292 		/* Free running cycle counter not supported, use time. */
293 		ptp->info->getcycles64 = ptp_getcycles64;
294 
295 		if (ptp->info->gettimex64)
296 			ptp->info->getcyclesx64 = ptp->info->gettimex64;
297 
298 		if (ptp->info->getcrosststamp)
299 			ptp->info->getcrosscycles = ptp->info->getcrosststamp;
300 	}
301 
302 	if (!ptp->info->enable)
303 		ptp->info->enable = ptp_enable;
304 
305 	if (ptp->info->do_aux_work) {
306 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
307 		ptp->kworker = kthread_run_worker(0, "ptp%d", ptp->index);
308 		if (IS_ERR(ptp->kworker)) {
309 			err = PTR_ERR(ptp->kworker);
310 			pr_err("failed to create ptp aux_worker %d\n", err);
311 			goto kworker_err;
312 		}
313 	}
314 
315 	/* PTP virtual clock is being registered under physical clock */
316 	if (parent && parent->class && parent->class->name &&
317 	    strcmp(parent->class->name, "ptp") == 0)
318 		ptp->is_virtual_clock = true;
319 
320 	if (!ptp->is_virtual_clock) {
321 		ptp->max_vclocks = PTP_DEFAULT_MAX_VCLOCKS;
322 
323 		size = sizeof(int) * ptp->max_vclocks;
324 		ptp->vclock_index = kzalloc(size, GFP_KERNEL);
325 		if (!ptp->vclock_index) {
326 			err = -ENOMEM;
327 			goto no_mem_for_vclocks;
328 		}
329 	}
330 
331 	err = ptp_populate_pin_groups(ptp);
332 	if (err)
333 		goto no_pin_groups;
334 
335 	/* Register a new PPS source. */
336 	if (info->pps) {
337 		struct pps_source_info pps;
338 		memset(&pps, 0, sizeof(pps));
339 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
340 		pps.mode = PTP_PPS_MODE;
341 		pps.owner = info->owner;
342 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
343 		if (IS_ERR(ptp->pps_source)) {
344 			err = PTR_ERR(ptp->pps_source);
345 			pr_err("failed to register pps source\n");
346 			goto no_pps;
347 		}
348 		ptp->pps_source->lookup_cookie = ptp;
349 	}
350 
351 	/* Initialize a new device of our class in our clock structure. */
352 	device_initialize(&ptp->dev);
353 	ptp->dev.devt = ptp->devid;
354 	ptp->dev.class = &ptp_class;
355 	ptp->dev.parent = parent;
356 	ptp->dev.groups = ptp->pin_attr_groups;
357 	ptp->dev.release = ptp_clock_release;
358 	dev_set_drvdata(&ptp->dev, ptp);
359 	dev_set_name(&ptp->dev, "ptp%d", ptp->index);
360 
361 	/* Create a posix clock and link it to the device. */
362 	err = posix_clock_register(&ptp->clock, &ptp->dev);
363 	if (err) {
364 		if (ptp->pps_source)
365 			pps_unregister_source(ptp->pps_source);
366 
367 		if (ptp->kworker)
368 			kthread_destroy_worker(ptp->kworker);
369 
370 		put_device(&ptp->dev);
371 
372 		pr_err("failed to create posix clock\n");
373 		return ERR_PTR(err);
374 	}
375 
376 	/* Debugfs initialization */
377 	snprintf(debugfsname, sizeof(debugfsname), "ptp%d", ptp->index);
378 	ptp->debugfs_root = debugfs_create_dir(debugfsname, NULL);
379 
380 	return ptp;
381 
382 no_pps:
383 	ptp_cleanup_pin_groups(ptp);
384 no_pin_groups:
385 	kfree(ptp->vclock_index);
386 no_mem_for_vclocks:
387 	if (ptp->kworker)
388 		kthread_destroy_worker(ptp->kworker);
389 kworker_err:
390 	mutex_destroy(&ptp->pincfg_mux);
391 	mutex_destroy(&ptp->n_vclocks_mux);
392 	bitmap_free(queue->mask);
393 no_memory_bitmap:
394 	list_del(&queue->qlist);
395 	kfree(queue);
396 no_memory_queue:
397 	xa_erase(&ptp_clocks_map, index);
398 no_slot:
399 	kfree(ptp);
400 no_memory:
401 	return ERR_PTR(err);
402 }
403 EXPORT_SYMBOL(ptp_clock_register);
404 
405 static int unregister_vclock(struct device *dev, void *data)
406 {
407 	struct ptp_clock *ptp = dev_get_drvdata(dev);
408 
409 	ptp_vclock_unregister(info_to_vclock(ptp->info));
410 	return 0;
411 }
412 
413 int ptp_clock_unregister(struct ptp_clock *ptp)
414 {
415 	if (ptp_vclock_in_use(ptp)) {
416 		device_for_each_child(&ptp->dev, NULL, unregister_vclock);
417 	}
418 
419 	ptp->defunct = 1;
420 	wake_up_interruptible(&ptp->tsev_wq);
421 
422 	if (ptp->kworker) {
423 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
424 		kthread_destroy_worker(ptp->kworker);
425 	}
426 
427 	/* Release the clock's resources. */
428 	if (ptp->pps_source)
429 		pps_unregister_source(ptp->pps_source);
430 
431 	posix_clock_unregister(&ptp->clock);
432 
433 	return 0;
434 }
435 EXPORT_SYMBOL(ptp_clock_unregister);
436 
437 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
438 {
439 	struct timestamp_event_queue *tsevq;
440 	struct pps_event_time evt;
441 	unsigned long flags;
442 
443 	switch (event->type) {
444 
445 	case PTP_CLOCK_ALARM:
446 		break;
447 
448 	case PTP_CLOCK_EXTTS:
449 	case PTP_CLOCK_EXTOFF:
450 		/* Enqueue timestamp on selected queues */
451 		spin_lock_irqsave(&ptp->tsevqs_lock, flags);
452 		list_for_each_entry(tsevq, &ptp->tsevqs, qlist) {
453 			if (test_bit((unsigned int)event->index, tsevq->mask))
454 				enqueue_external_timestamp(tsevq, event);
455 		}
456 		spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
457 		wake_up_interruptible(&ptp->tsev_wq);
458 		break;
459 
460 	case PTP_CLOCK_PPS:
461 		pps_get_ts(&evt);
462 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
463 		break;
464 
465 	case PTP_CLOCK_PPSUSR:
466 		pps_event(ptp->pps_source, &event->pps_times,
467 			  PTP_PPS_EVENT, NULL);
468 		break;
469 	}
470 }
471 EXPORT_SYMBOL(ptp_clock_event);
472 
473 int ptp_clock_index(struct ptp_clock *ptp)
474 {
475 	return ptp->index;
476 }
477 EXPORT_SYMBOL(ptp_clock_index);
478 
479 int ptp_find_pin(struct ptp_clock *ptp,
480 		 enum ptp_pin_function func, unsigned int chan)
481 {
482 	struct ptp_pin_desc *pin = NULL;
483 	int i;
484 
485 	for (i = 0; i < ptp->info->n_pins; i++) {
486 		if (ptp->info->pin_config[i].func == func &&
487 		    ptp->info->pin_config[i].chan == chan) {
488 			pin = &ptp->info->pin_config[i];
489 			break;
490 		}
491 	}
492 
493 	return pin ? i : -1;
494 }
495 EXPORT_SYMBOL(ptp_find_pin);
496 
497 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
498 			  enum ptp_pin_function func, unsigned int chan)
499 {
500 	int result;
501 
502 	mutex_lock(&ptp->pincfg_mux);
503 
504 	result = ptp_find_pin(ptp, func, chan);
505 
506 	mutex_unlock(&ptp->pincfg_mux);
507 
508 	return result;
509 }
510 EXPORT_SYMBOL(ptp_find_pin_unlocked);
511 
512 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
513 {
514 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
515 }
516 EXPORT_SYMBOL(ptp_schedule_worker);
517 
518 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
519 {
520 	kthread_cancel_delayed_work_sync(&ptp->aux_work);
521 }
522 EXPORT_SYMBOL(ptp_cancel_worker_sync);
523 
524 /* module operations */
525 
526 static void __exit ptp_exit(void)
527 {
528 	class_unregister(&ptp_class);
529 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
530 	xa_destroy(&ptp_clocks_map);
531 }
532 
533 static int __init ptp_init(void)
534 {
535 	int err;
536 
537 	err = class_register(&ptp_class);
538 	if (err) {
539 		pr_err("ptp: failed to allocate class\n");
540 		return err;
541 	}
542 
543 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
544 	if (err < 0) {
545 		pr_err("ptp: failed to allocate device region\n");
546 		goto no_region;
547 	}
548 
549 	pr_info("PTP clock support registered\n");
550 	return 0;
551 
552 no_region:
553 	class_unregister(&ptp_class);
554 	return err;
555 }
556 
557 subsys_initcall(ptp_init);
558 module_exit(ptp_exit);
559 
560 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
561 MODULE_DESCRIPTION("PTP clocks support");
562 MODULE_LICENSE("GPL");
563