xref: /linux/drivers/ptp/ptp_clock.c (revision daa2be74b1b2302004945b2a5e32424e177cc7da) 
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 		ptp->dialed_frequency = tx->freq;
154 	} else if (tx->modes & ADJ_OFFSET) {
155 		if (ops->adjphase) {
156 			s32 max_phase_adj = ops->getmaxphase(ops);
157 			s32 offset = tx->offset;
158 
159 			if (!(tx->modes & ADJ_NANO))
160 				offset *= NSEC_PER_USEC;
161 
162 			if (offset > max_phase_adj || offset < -max_phase_adj)
163 				return -ERANGE;
164 
165 			err = ops->adjphase(ops, offset);
166 		}
167 	} else if (tx->modes == 0) {
168 		tx->freq = ptp->dialed_frequency;
169 		err = 0;
170 	}
171 
172 	return err;
173 }
174 
175 static struct posix_clock_operations ptp_clock_ops = {
176 	.owner		= THIS_MODULE,
177 	.clock_adjtime	= ptp_clock_adjtime,
178 	.clock_gettime	= ptp_clock_gettime,
179 	.clock_getres	= ptp_clock_getres,
180 	.clock_settime	= ptp_clock_settime,
181 	.ioctl		= ptp_ioctl,
182 	.open		= ptp_open,
183 	.release	= ptp_release,
184 	.poll		= ptp_poll,
185 	.read		= ptp_read,
186 };
187 
188 static void ptp_clock_release(struct device *dev)
189 {
190 	struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
191 	struct timestamp_event_queue *tsevq;
192 	unsigned long flags;
193 
194 	ptp_cleanup_pin_groups(ptp);
195 	kfree(ptp->vclock_index);
196 	mutex_destroy(&ptp->pincfg_mux);
197 	mutex_destroy(&ptp->n_vclocks_mux);
198 	/* Delete first entry */
199 	spin_lock_irqsave(&ptp->tsevqs_lock, flags);
200 	tsevq = list_first_entry(&ptp->tsevqs, struct timestamp_event_queue,
201 				 qlist);
202 	list_del(&tsevq->qlist);
203 	spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
204 	bitmap_free(tsevq->mask);
205 	kfree(tsevq);
206 	debugfs_remove(ptp->debugfs_root);
207 	xa_erase(&ptp_clocks_map, ptp->index);
208 	kfree(ptp);
209 }
210 
211 static int ptp_getcycles64(struct ptp_clock_info *info, struct timespec64 *ts)
212 {
213 	if (info->getcyclesx64)
214 		return info->getcyclesx64(info, ts, NULL);
215 	else
216 		return info->gettime64(info, ts);
217 }
218 
219 static void ptp_aux_kworker(struct kthread_work *work)
220 {
221 	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
222 					     aux_work.work);
223 	struct ptp_clock_info *info = ptp->info;
224 	long delay;
225 
226 	delay = info->do_aux_work(info);
227 
228 	if (delay >= 0)
229 		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
230 }
231 
232 /* public interface */
233 
234 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
235 				     struct device *parent)
236 {
237 	struct ptp_clock *ptp;
238 	struct timestamp_event_queue *queue = NULL;
239 	int err, index, major = MAJOR(ptp_devt);
240 	char debugfsname[16];
241 	size_t size;
242 
243 	if (info->n_alarm > PTP_MAX_ALARMS)
244 		return ERR_PTR(-EINVAL);
245 
246 	/* Initialize a clock structure. */
247 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
248 	if (!ptp) {
249 		err = -ENOMEM;
250 		goto no_memory;
251 	}
252 
253 	err = xa_alloc(&ptp_clocks_map, &index, ptp, xa_limit_31b,
254 		       GFP_KERNEL);
255 	if (err)
256 		goto no_slot;
257 
258 	ptp->clock.ops = ptp_clock_ops;
259 	ptp->info = info;
260 	ptp->devid = MKDEV(major, index);
261 	ptp->index = index;
262 	INIT_LIST_HEAD(&ptp->tsevqs);
263 	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
264 	if (!queue) {
265 		err = -ENOMEM;
266 		goto no_memory_queue;
267 	}
268 	list_add_tail(&queue->qlist, &ptp->tsevqs);
269 	spin_lock_init(&ptp->tsevqs_lock);
270 	queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL);
271 	if (!queue->mask) {
272 		err = -ENOMEM;
273 		goto no_memory_bitmap;
274 	}
275 	bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS);
276 	spin_lock_init(&queue->lock);
277 	mutex_init(&ptp->pincfg_mux);
278 	mutex_init(&ptp->n_vclocks_mux);
279 	init_waitqueue_head(&ptp->tsev_wq);
280 
281 	if (ptp->info->getcycles64 || ptp->info->getcyclesx64) {
282 		ptp->has_cycles = true;
283 		if (!ptp->info->getcycles64 && ptp->info->getcyclesx64)
284 			ptp->info->getcycles64 = ptp_getcycles64;
285 	} else {
286 		/* Free running cycle counter not supported, use time. */
287 		ptp->info->getcycles64 = ptp_getcycles64;
288 
289 		if (ptp->info->gettimex64)
290 			ptp->info->getcyclesx64 = ptp->info->gettimex64;
291 
292 		if (ptp->info->getcrosststamp)
293 			ptp->info->getcrosscycles = ptp->info->getcrosststamp;
294 	}
295 
296 	if (ptp->info->do_aux_work) {
297 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
298 		ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
299 		if (IS_ERR(ptp->kworker)) {
300 			err = PTR_ERR(ptp->kworker);
301 			pr_err("failed to create ptp aux_worker %d\n", err);
302 			goto kworker_err;
303 		}
304 	}
305 
306 	/* PTP virtual clock is being registered under physical clock */
307 	if (parent && parent->class && parent->class->name &&
308 	    strcmp(parent->class->name, "ptp") == 0)
309 		ptp->is_virtual_clock = true;
310 
311 	if (!ptp->is_virtual_clock) {
312 		ptp->max_vclocks = PTP_DEFAULT_MAX_VCLOCKS;
313 
314 		size = sizeof(int) * ptp->max_vclocks;
315 		ptp->vclock_index = kzalloc(size, GFP_KERNEL);
316 		if (!ptp->vclock_index) {
317 			err = -ENOMEM;
318 			goto no_mem_for_vclocks;
319 		}
320 	}
321 
322 	err = ptp_populate_pin_groups(ptp);
323 	if (err)
324 		goto no_pin_groups;
325 
326 	/* Register a new PPS source. */
327 	if (info->pps) {
328 		struct pps_source_info pps;
329 		memset(&pps, 0, sizeof(pps));
330 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
331 		pps.mode = PTP_PPS_MODE;
332 		pps.owner = info->owner;
333 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
334 		if (IS_ERR(ptp->pps_source)) {
335 			err = PTR_ERR(ptp->pps_source);
336 			pr_err("failed to register pps source\n");
337 			goto no_pps;
338 		}
339 		ptp->pps_source->lookup_cookie = ptp;
340 	}
341 
342 	/* Initialize a new device of our class in our clock structure. */
343 	device_initialize(&ptp->dev);
344 	ptp->dev.devt = ptp->devid;
345 	ptp->dev.class = &ptp_class;
346 	ptp->dev.parent = parent;
347 	ptp->dev.groups = ptp->pin_attr_groups;
348 	ptp->dev.release = ptp_clock_release;
349 	dev_set_drvdata(&ptp->dev, ptp);
350 	dev_set_name(&ptp->dev, "ptp%d", ptp->index);
351 
352 	/* Create a posix clock and link it to the device. */
353 	err = posix_clock_register(&ptp->clock, &ptp->dev);
354 	if (err) {
355 		if (ptp->pps_source)
356 			pps_unregister_source(ptp->pps_source);
357 
358 		if (ptp->kworker)
359 			kthread_destroy_worker(ptp->kworker);
360 
361 		put_device(&ptp->dev);
362 
363 		pr_err("failed to create posix clock\n");
364 		return ERR_PTR(err);
365 	}
366 
367 	/* Debugfs initialization */
368 	snprintf(debugfsname, sizeof(debugfsname), "ptp%d", ptp->index);
369 	ptp->debugfs_root = debugfs_create_dir(debugfsname, NULL);
370 
371 	return ptp;
372 
373 no_pps:
374 	ptp_cleanup_pin_groups(ptp);
375 no_pin_groups:
376 	kfree(ptp->vclock_index);
377 no_mem_for_vclocks:
378 	if (ptp->kworker)
379 		kthread_destroy_worker(ptp->kworker);
380 kworker_err:
381 	mutex_destroy(&ptp->pincfg_mux);
382 	mutex_destroy(&ptp->n_vclocks_mux);
383 	bitmap_free(queue->mask);
384 no_memory_bitmap:
385 	list_del(&queue->qlist);
386 	kfree(queue);
387 no_memory_queue:
388 	xa_erase(&ptp_clocks_map, index);
389 no_slot:
390 	kfree(ptp);
391 no_memory:
392 	return ERR_PTR(err);
393 }
394 EXPORT_SYMBOL(ptp_clock_register);
395 
396 static int unregister_vclock(struct device *dev, void *data)
397 {
398 	struct ptp_clock *ptp = dev_get_drvdata(dev);
399 
400 	ptp_vclock_unregister(info_to_vclock(ptp->info));
401 	return 0;
402 }
403 
404 int ptp_clock_unregister(struct ptp_clock *ptp)
405 {
406 	if (ptp_vclock_in_use(ptp)) {
407 		device_for_each_child(&ptp->dev, NULL, unregister_vclock);
408 	}
409 
410 	ptp->defunct = 1;
411 	wake_up_interruptible(&ptp->tsev_wq);
412 
413 	if (ptp->kworker) {
414 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
415 		kthread_destroy_worker(ptp->kworker);
416 	}
417 
418 	/* Release the clock's resources. */
419 	if (ptp->pps_source)
420 		pps_unregister_source(ptp->pps_source);
421 
422 	posix_clock_unregister(&ptp->clock);
423 
424 	return 0;
425 }
426 EXPORT_SYMBOL(ptp_clock_unregister);
427 
428 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
429 {
430 	struct timestamp_event_queue *tsevq;
431 	struct pps_event_time evt;
432 	unsigned long flags;
433 
434 	switch (event->type) {
435 
436 	case PTP_CLOCK_ALARM:
437 		break;
438 
439 	case PTP_CLOCK_EXTTS:
440 	case PTP_CLOCK_EXTOFF:
441 		/* Enqueue timestamp on selected queues */
442 		spin_lock_irqsave(&ptp->tsevqs_lock, flags);
443 		list_for_each_entry(tsevq, &ptp->tsevqs, qlist) {
444 			if (test_bit((unsigned int)event->index, tsevq->mask))
445 				enqueue_external_timestamp(tsevq, event);
446 		}
447 		spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
448 		wake_up_interruptible(&ptp->tsev_wq);
449 		break;
450 
451 	case PTP_CLOCK_PPS:
452 		pps_get_ts(&evt);
453 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
454 		break;
455 
456 	case PTP_CLOCK_PPSUSR:
457 		pps_event(ptp->pps_source, &event->pps_times,
458 			  PTP_PPS_EVENT, NULL);
459 		break;
460 	}
461 }
462 EXPORT_SYMBOL(ptp_clock_event);
463 
464 int ptp_clock_index(struct ptp_clock *ptp)
465 {
466 	return ptp->index;
467 }
468 EXPORT_SYMBOL(ptp_clock_index);
469 
470 int ptp_find_pin(struct ptp_clock *ptp,
471 		 enum ptp_pin_function func, unsigned int chan)
472 {
473 	struct ptp_pin_desc *pin = NULL;
474 	int i;
475 
476 	for (i = 0; i < ptp->info->n_pins; i++) {
477 		if (ptp->info->pin_config[i].func == func &&
478 		    ptp->info->pin_config[i].chan == chan) {
479 			pin = &ptp->info->pin_config[i];
480 			break;
481 		}
482 	}
483 
484 	return pin ? i : -1;
485 }
486 EXPORT_SYMBOL(ptp_find_pin);
487 
488 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
489 			  enum ptp_pin_function func, unsigned int chan)
490 {
491 	int result;
492 
493 	mutex_lock(&ptp->pincfg_mux);
494 
495 	result = ptp_find_pin(ptp, func, chan);
496 
497 	mutex_unlock(&ptp->pincfg_mux);
498 
499 	return result;
500 }
501 EXPORT_SYMBOL(ptp_find_pin_unlocked);
502 
503 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
504 {
505 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
506 }
507 EXPORT_SYMBOL(ptp_schedule_worker);
508 
509 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
510 {
511 	kthread_cancel_delayed_work_sync(&ptp->aux_work);
512 }
513 EXPORT_SYMBOL(ptp_cancel_worker_sync);
514 
515 /* module operations */
516 
517 static void __exit ptp_exit(void)
518 {
519 	class_unregister(&ptp_class);
520 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
521 	xa_destroy(&ptp_clocks_map);
522 }
523 
524 static int __init ptp_init(void)
525 {
526 	int err;
527 
528 	err = class_register(&ptp_class);
529 	if (err) {
530 		pr_err("ptp: failed to allocate class\n");
531 		return err;
532 	}
533 
534 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
535 	if (err < 0) {
536 		pr_err("ptp: failed to allocate device region\n");
537 		goto no_region;
538 	}
539 
540 	pr_info("PTP clock support registered\n");
541 	return 0;
542 
543 no_region:
544 	class_unregister(&ptp_class);
545 	return err;
546 }
547 
548 subsys_initcall(ptp_init);
549 module_exit(ptp_exit);
550 
551 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
552 MODULE_DESCRIPTION("PTP clocks support");
553 MODULE_LICENSE("GPL");
554