xref: /linux/drivers/ptp/ptp_clock.c (revision 79d2e1919a2728ef49d938eb20ebd5903c14dfb0) 
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 void ptp_aux_kworker(struct kthread_work *work)
221 {
222 	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
223 					     aux_work.work);
224 	struct ptp_clock_info *info = ptp->info;
225 	long delay;
226 
227 	delay = info->do_aux_work(info);
228 
229 	if (delay >= 0)
230 		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
231 }
232 
233 /* public interface */
234 
235 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
236 				     struct device *parent)
237 {
238 	struct ptp_clock *ptp;
239 	struct timestamp_event_queue *queue = NULL;
240 	int err, index, major = MAJOR(ptp_devt);
241 	char debugfsname[16];
242 	size_t size;
243 
244 	if (info->n_alarm > PTP_MAX_ALARMS)
245 		return ERR_PTR(-EINVAL);
246 
247 	/* Initialize a clock structure. */
248 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
249 	if (!ptp) {
250 		err = -ENOMEM;
251 		goto no_memory;
252 	}
253 
254 	err = xa_alloc(&ptp_clocks_map, &index, ptp, xa_limit_31b,
255 		       GFP_KERNEL);
256 	if (err)
257 		goto no_slot;
258 
259 	ptp->clock.ops = ptp_clock_ops;
260 	ptp->info = info;
261 	ptp->devid = MKDEV(major, index);
262 	ptp->index = index;
263 	INIT_LIST_HEAD(&ptp->tsevqs);
264 	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
265 	if (!queue) {
266 		err = -ENOMEM;
267 		goto no_memory_queue;
268 	}
269 	list_add_tail(&queue->qlist, &ptp->tsevqs);
270 	spin_lock_init(&ptp->tsevqs_lock);
271 	queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL);
272 	if (!queue->mask) {
273 		err = -ENOMEM;
274 		goto no_memory_bitmap;
275 	}
276 	bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS);
277 	spin_lock_init(&queue->lock);
278 	mutex_init(&ptp->pincfg_mux);
279 	mutex_init(&ptp->n_vclocks_mux);
280 	init_waitqueue_head(&ptp->tsev_wq);
281 
282 	if (ptp->info->getcycles64 || ptp->info->getcyclesx64) {
283 		ptp->has_cycles = true;
284 		if (!ptp->info->getcycles64 && ptp->info->getcyclesx64)
285 			ptp->info->getcycles64 = ptp_getcycles64;
286 	} else {
287 		/* Free running cycle counter not supported, use time. */
288 		ptp->info->getcycles64 = ptp_getcycles64;
289 
290 		if (ptp->info->gettimex64)
291 			ptp->info->getcyclesx64 = ptp->info->gettimex64;
292 
293 		if (ptp->info->getcrosststamp)
294 			ptp->info->getcrosscycles = ptp->info->getcrosststamp;
295 	}
296 
297 	if (ptp->info->do_aux_work) {
298 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
299 		ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
300 		if (IS_ERR(ptp->kworker)) {
301 			err = PTR_ERR(ptp->kworker);
302 			pr_err("failed to create ptp aux_worker %d\n", err);
303 			goto kworker_err;
304 		}
305 	}
306 
307 	/* PTP virtual clock is being registered under physical clock */
308 	if (parent && parent->class && parent->class->name &&
309 	    strcmp(parent->class->name, "ptp") == 0)
310 		ptp->is_virtual_clock = true;
311 
312 	if (!ptp->is_virtual_clock) {
313 		ptp->max_vclocks = PTP_DEFAULT_MAX_VCLOCKS;
314 
315 		size = sizeof(int) * ptp->max_vclocks;
316 		ptp->vclock_index = kzalloc(size, GFP_KERNEL);
317 		if (!ptp->vclock_index) {
318 			err = -ENOMEM;
319 			goto no_mem_for_vclocks;
320 		}
321 	}
322 
323 	err = ptp_populate_pin_groups(ptp);
324 	if (err)
325 		goto no_pin_groups;
326 
327 	/* Register a new PPS source. */
328 	if (info->pps) {
329 		struct pps_source_info pps;
330 		memset(&pps, 0, sizeof(pps));
331 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
332 		pps.mode = PTP_PPS_MODE;
333 		pps.owner = info->owner;
334 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
335 		if (IS_ERR(ptp->pps_source)) {
336 			err = PTR_ERR(ptp->pps_source);
337 			pr_err("failed to register pps source\n");
338 			goto no_pps;
339 		}
340 		ptp->pps_source->lookup_cookie = ptp;
341 	}
342 
343 	/* Initialize a new device of our class in our clock structure. */
344 	device_initialize(&ptp->dev);
345 	ptp->dev.devt = ptp->devid;
346 	ptp->dev.class = &ptp_class;
347 	ptp->dev.parent = parent;
348 	ptp->dev.groups = ptp->pin_attr_groups;
349 	ptp->dev.release = ptp_clock_release;
350 	dev_set_drvdata(&ptp->dev, ptp);
351 	dev_set_name(&ptp->dev, "ptp%d", ptp->index);
352 
353 	/* Create a posix clock and link it to the device. */
354 	err = posix_clock_register(&ptp->clock, &ptp->dev);
355 	if (err) {
356 		if (ptp->pps_source)
357 			pps_unregister_source(ptp->pps_source);
358 
359 		if (ptp->kworker)
360 			kthread_destroy_worker(ptp->kworker);
361 
362 		put_device(&ptp->dev);
363 
364 		pr_err("failed to create posix clock\n");
365 		return ERR_PTR(err);
366 	}
367 
368 	/* Debugfs initialization */
369 	snprintf(debugfsname, sizeof(debugfsname), "ptp%d", ptp->index);
370 	ptp->debugfs_root = debugfs_create_dir(debugfsname, NULL);
371 
372 	return ptp;
373 
374 no_pps:
375 	ptp_cleanup_pin_groups(ptp);
376 no_pin_groups:
377 	kfree(ptp->vclock_index);
378 no_mem_for_vclocks:
379 	if (ptp->kworker)
380 		kthread_destroy_worker(ptp->kworker);
381 kworker_err:
382 	mutex_destroy(&ptp->pincfg_mux);
383 	mutex_destroy(&ptp->n_vclocks_mux);
384 	bitmap_free(queue->mask);
385 no_memory_bitmap:
386 	list_del(&queue->qlist);
387 	kfree(queue);
388 no_memory_queue:
389 	xa_erase(&ptp_clocks_map, index);
390 no_slot:
391 	kfree(ptp);
392 no_memory:
393 	return ERR_PTR(err);
394 }
395 EXPORT_SYMBOL(ptp_clock_register);
396 
397 static int unregister_vclock(struct device *dev, void *data)
398 {
399 	struct ptp_clock *ptp = dev_get_drvdata(dev);
400 
401 	ptp_vclock_unregister(info_to_vclock(ptp->info));
402 	return 0;
403 }
404 
405 int ptp_clock_unregister(struct ptp_clock *ptp)
406 {
407 	if (ptp_vclock_in_use(ptp)) {
408 		device_for_each_child(&ptp->dev, NULL, unregister_vclock);
409 	}
410 
411 	ptp->defunct = 1;
412 	wake_up_interruptible(&ptp->tsev_wq);
413 
414 	if (ptp->kworker) {
415 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
416 		kthread_destroy_worker(ptp->kworker);
417 	}
418 
419 	/* Release the clock's resources. */
420 	if (ptp->pps_source)
421 		pps_unregister_source(ptp->pps_source);
422 
423 	posix_clock_unregister(&ptp->clock);
424 
425 	return 0;
426 }
427 EXPORT_SYMBOL(ptp_clock_unregister);
428 
429 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
430 {
431 	struct timestamp_event_queue *tsevq;
432 	struct pps_event_time evt;
433 	unsigned long flags;
434 
435 	switch (event->type) {
436 
437 	case PTP_CLOCK_ALARM:
438 		break;
439 
440 	case PTP_CLOCK_EXTTS:
441 	case PTP_CLOCK_EXTOFF:
442 		/* Enqueue timestamp on selected queues */
443 		spin_lock_irqsave(&ptp->tsevqs_lock, flags);
444 		list_for_each_entry(tsevq, &ptp->tsevqs, qlist) {
445 			if (test_bit((unsigned int)event->index, tsevq->mask))
446 				enqueue_external_timestamp(tsevq, event);
447 		}
448 		spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
449 		wake_up_interruptible(&ptp->tsev_wq);
450 		break;
451 
452 	case PTP_CLOCK_PPS:
453 		pps_get_ts(&evt);
454 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
455 		break;
456 
457 	case PTP_CLOCK_PPSUSR:
458 		pps_event(ptp->pps_source, &event->pps_times,
459 			  PTP_PPS_EVENT, NULL);
460 		break;
461 	}
462 }
463 EXPORT_SYMBOL(ptp_clock_event);
464 
465 int ptp_clock_index(struct ptp_clock *ptp)
466 {
467 	return ptp->index;
468 }
469 EXPORT_SYMBOL(ptp_clock_index);
470 
471 int ptp_find_pin(struct ptp_clock *ptp,
472 		 enum ptp_pin_function func, unsigned int chan)
473 {
474 	struct ptp_pin_desc *pin = NULL;
475 	int i;
476 
477 	for (i = 0; i < ptp->info->n_pins; i++) {
478 		if (ptp->info->pin_config[i].func == func &&
479 		    ptp->info->pin_config[i].chan == chan) {
480 			pin = &ptp->info->pin_config[i];
481 			break;
482 		}
483 	}
484 
485 	return pin ? i : -1;
486 }
487 EXPORT_SYMBOL(ptp_find_pin);
488 
489 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
490 			  enum ptp_pin_function func, unsigned int chan)
491 {
492 	int result;
493 
494 	mutex_lock(&ptp->pincfg_mux);
495 
496 	result = ptp_find_pin(ptp, func, chan);
497 
498 	mutex_unlock(&ptp->pincfg_mux);
499 
500 	return result;
501 }
502 EXPORT_SYMBOL(ptp_find_pin_unlocked);
503 
504 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
505 {
506 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
507 }
508 EXPORT_SYMBOL(ptp_schedule_worker);
509 
510 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
511 {
512 	kthread_cancel_delayed_work_sync(&ptp->aux_work);
513 }
514 EXPORT_SYMBOL(ptp_cancel_worker_sync);
515 
516 /* module operations */
517 
518 static void __exit ptp_exit(void)
519 {
520 	class_unregister(&ptp_class);
521 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
522 	xa_destroy(&ptp_clocks_map);
523 }
524 
525 static int __init ptp_init(void)
526 {
527 	int err;
528 
529 	err = class_register(&ptp_class);
530 	if (err) {
531 		pr_err("ptp: failed to allocate class\n");
532 		return err;
533 	}
534 
535 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
536 	if (err < 0) {
537 		pr_err("ptp: failed to allocate device region\n");
538 		goto no_region;
539 	}
540 
541 	pr_info("PTP clock support registered\n");
542 	return 0;
543 
544 no_region:
545 	class_unregister(&ptp_class);
546 	return err;
547 }
548 
549 subsys_initcall(ptp_init);
550 module_exit(ptp_exit);
551 
552 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
553 MODULE_DESCRIPTION("PTP clocks support");
554 MODULE_LICENSE("GPL");
555