xref: /linux/drivers/ptp/ptp_clock.c (revision c4101e55974cc7d835fbd2d8e01553a3f61e9e75) 
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/idr.h>
8 #include <linux/device.h>
9 #include <linux/err.h>
10 #include <linux/init.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/posix-clock.h>
14 #include <linux/pps_kernel.h>
15 #include <linux/slab.h>
16 #include <linux/syscalls.h>
17 #include <linux/uaccess.h>
18 #include <linux/debugfs.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 struct class *ptp_class;
29 
30 /* private globals */
31 
32 static dev_t ptp_devt;
33 
34 static DEFINE_IDA(ptp_clocks_map);
35 
36 /* time stamp event queue operations */
37 
38 static inline int queue_free(struct timestamp_event_queue *q)
39 {
40 	return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
41 }
42 
43 static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
44 				       struct ptp_clock_event *src)
45 {
46 	struct ptp_extts_event *dst;
47 	unsigned long flags;
48 	s64 seconds;
49 	u32 remainder;
50 
51 	seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
52 
53 	spin_lock_irqsave(&queue->lock, flags);
54 
55 	dst = &queue->buf[queue->tail];
56 	dst->index = src->index;
57 	dst->t.sec = seconds;
58 	dst->t.nsec = remainder;
59 
60 	/* Both WRITE_ONCE() are paired with READ_ONCE() in queue_cnt() */
61 	if (!queue_free(queue))
62 		WRITE_ONCE(queue->head, (queue->head + 1) % PTP_MAX_TIMESTAMPS);
63 
64 	WRITE_ONCE(queue->tail, (queue->tail + 1) % PTP_MAX_TIMESTAMPS);
65 
66 	spin_unlock_irqrestore(&queue->lock, flags);
67 }
68 
69 /* posix clock implementation */
70 
71 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
72 {
73 	tp->tv_sec = 0;
74 	tp->tv_nsec = 1;
75 	return 0;
76 }
77 
78 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
79 {
80 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
81 
82 	if (ptp_clock_freerun(ptp)) {
83 		pr_err("ptp: physical clock is free running\n");
84 		return -EBUSY;
85 	}
86 
87 	return  ptp->info->settime64(ptp->info, tp);
88 }
89 
90 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
91 {
92 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
93 	int err;
94 
95 	if (ptp->info->gettimex64)
96 		err = ptp->info->gettimex64(ptp->info, tp, NULL);
97 	else
98 		err = ptp->info->gettime64(ptp->info, tp);
99 	return err;
100 }
101 
102 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
103 {
104 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
105 	struct ptp_clock_info *ops;
106 	int err = -EOPNOTSUPP;
107 
108 	if (ptp_clock_freerun(ptp)) {
109 		pr_err("ptp: physical clock is free running\n");
110 		return -EBUSY;
111 	}
112 
113 	ops = ptp->info;
114 
115 	if (tx->modes & ADJ_SETOFFSET) {
116 		struct timespec64 ts;
117 		ktime_t kt;
118 		s64 delta;
119 
120 		ts.tv_sec  = tx->time.tv_sec;
121 		ts.tv_nsec = tx->time.tv_usec;
122 
123 		if (!(tx->modes & ADJ_NANO))
124 			ts.tv_nsec *= 1000;
125 
126 		if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
127 			return -EINVAL;
128 
129 		kt = timespec64_to_ktime(ts);
130 		delta = ktime_to_ns(kt);
131 		err = ops->adjtime(ops, delta);
132 	} else if (tx->modes & ADJ_FREQUENCY) {
133 		long ppb = scaled_ppm_to_ppb(tx->freq);
134 		if (ppb > ops->max_adj || ppb < -ops->max_adj)
135 			return -ERANGE;
136 		err = ops->adjfine(ops, tx->freq);
137 		ptp->dialed_frequency = tx->freq;
138 	} else if (tx->modes & ADJ_OFFSET) {
139 		if (ops->adjphase) {
140 			s32 max_phase_adj = ops->getmaxphase(ops);
141 			s32 offset = tx->offset;
142 
143 			if (!(tx->modes & ADJ_NANO))
144 				offset *= NSEC_PER_USEC;
145 
146 			if (offset > max_phase_adj || offset < -max_phase_adj)
147 				return -ERANGE;
148 
149 			err = ops->adjphase(ops, offset);
150 		}
151 	} else if (tx->modes == 0) {
152 		tx->freq = ptp->dialed_frequency;
153 		err = 0;
154 	}
155 
156 	return err;
157 }
158 
159 static struct posix_clock_operations ptp_clock_ops = {
160 	.owner		= THIS_MODULE,
161 	.clock_adjtime	= ptp_clock_adjtime,
162 	.clock_gettime	= ptp_clock_gettime,
163 	.clock_getres	= ptp_clock_getres,
164 	.clock_settime	= ptp_clock_settime,
165 	.ioctl		= ptp_ioctl,
166 	.open		= ptp_open,
167 	.release	= ptp_release,
168 	.poll		= ptp_poll,
169 	.read		= ptp_read,
170 };
171 
172 static void ptp_clock_release(struct device *dev)
173 {
174 	struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
175 	struct timestamp_event_queue *tsevq;
176 	unsigned long flags;
177 
178 	ptp_cleanup_pin_groups(ptp);
179 	kfree(ptp->vclock_index);
180 	mutex_destroy(&ptp->pincfg_mux);
181 	mutex_destroy(&ptp->n_vclocks_mux);
182 	/* Delete first entry */
183 	spin_lock_irqsave(&ptp->tsevqs_lock, flags);
184 	tsevq = list_first_entry(&ptp->tsevqs, struct timestamp_event_queue,
185 				 qlist);
186 	list_del(&tsevq->qlist);
187 	spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
188 	bitmap_free(tsevq->mask);
189 	kfree(tsevq);
190 	debugfs_remove(ptp->debugfs_root);
191 	ida_free(&ptp_clocks_map, ptp->index);
192 	kfree(ptp);
193 }
194 
195 static int ptp_getcycles64(struct ptp_clock_info *info, struct timespec64 *ts)
196 {
197 	if (info->getcyclesx64)
198 		return info->getcyclesx64(info, ts, NULL);
199 	else
200 		return info->gettime64(info, ts);
201 }
202 
203 static void ptp_aux_kworker(struct kthread_work *work)
204 {
205 	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
206 					     aux_work.work);
207 	struct ptp_clock_info *info = ptp->info;
208 	long delay;
209 
210 	delay = info->do_aux_work(info);
211 
212 	if (delay >= 0)
213 		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
214 }
215 
216 /* public interface */
217 
218 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
219 				     struct device *parent)
220 {
221 	struct ptp_clock *ptp;
222 	struct timestamp_event_queue *queue = NULL;
223 	int err = 0, index, major = MAJOR(ptp_devt);
224 	char debugfsname[16];
225 	size_t size;
226 
227 	if (info->n_alarm > PTP_MAX_ALARMS)
228 		return ERR_PTR(-EINVAL);
229 
230 	/* Initialize a clock structure. */
231 	err = -ENOMEM;
232 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
233 	if (ptp == NULL)
234 		goto no_memory;
235 
236 	index = ida_alloc_max(&ptp_clocks_map, MINORMASK, GFP_KERNEL);
237 	if (index < 0) {
238 		err = index;
239 		goto no_slot;
240 	}
241 
242 	ptp->clock.ops = ptp_clock_ops;
243 	ptp->info = info;
244 	ptp->devid = MKDEV(major, index);
245 	ptp->index = index;
246 	INIT_LIST_HEAD(&ptp->tsevqs);
247 	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
248 	if (!queue)
249 		goto no_memory_queue;
250 	list_add_tail(&queue->qlist, &ptp->tsevqs);
251 	spin_lock_init(&ptp->tsevqs_lock);
252 	queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL);
253 	if (!queue->mask)
254 		goto no_memory_bitmap;
255 	bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS);
256 	spin_lock_init(&queue->lock);
257 	mutex_init(&ptp->pincfg_mux);
258 	mutex_init(&ptp->n_vclocks_mux);
259 	init_waitqueue_head(&ptp->tsev_wq);
260 
261 	if (ptp->info->getcycles64 || ptp->info->getcyclesx64) {
262 		ptp->has_cycles = true;
263 		if (!ptp->info->getcycles64 && ptp->info->getcyclesx64)
264 			ptp->info->getcycles64 = ptp_getcycles64;
265 	} else {
266 		/* Free running cycle counter not supported, use time. */
267 		ptp->info->getcycles64 = ptp_getcycles64;
268 
269 		if (ptp->info->gettimex64)
270 			ptp->info->getcyclesx64 = ptp->info->gettimex64;
271 
272 		if (ptp->info->getcrosststamp)
273 			ptp->info->getcrosscycles = ptp->info->getcrosststamp;
274 	}
275 
276 	if (ptp->info->do_aux_work) {
277 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
278 		ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
279 		if (IS_ERR(ptp->kworker)) {
280 			err = PTR_ERR(ptp->kworker);
281 			pr_err("failed to create ptp aux_worker %d\n", err);
282 			goto kworker_err;
283 		}
284 	}
285 
286 	/* PTP virtual clock is being registered under physical clock */
287 	if (parent && parent->class && parent->class->name &&
288 	    strcmp(parent->class->name, "ptp") == 0)
289 		ptp->is_virtual_clock = true;
290 
291 	if (!ptp->is_virtual_clock) {
292 		ptp->max_vclocks = PTP_DEFAULT_MAX_VCLOCKS;
293 
294 		size = sizeof(int) * ptp->max_vclocks;
295 		ptp->vclock_index = kzalloc(size, GFP_KERNEL);
296 		if (!ptp->vclock_index) {
297 			err = -ENOMEM;
298 			goto no_mem_for_vclocks;
299 		}
300 	}
301 
302 	err = ptp_populate_pin_groups(ptp);
303 	if (err)
304 		goto no_pin_groups;
305 
306 	/* Register a new PPS source. */
307 	if (info->pps) {
308 		struct pps_source_info pps;
309 		memset(&pps, 0, sizeof(pps));
310 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
311 		pps.mode = PTP_PPS_MODE;
312 		pps.owner = info->owner;
313 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
314 		if (IS_ERR(ptp->pps_source)) {
315 			err = PTR_ERR(ptp->pps_source);
316 			pr_err("failed to register pps source\n");
317 			goto no_pps;
318 		}
319 		ptp->pps_source->lookup_cookie = ptp;
320 	}
321 
322 	/* Initialize a new device of our class in our clock structure. */
323 	device_initialize(&ptp->dev);
324 	ptp->dev.devt = ptp->devid;
325 	ptp->dev.class = ptp_class;
326 	ptp->dev.parent = parent;
327 	ptp->dev.groups = ptp->pin_attr_groups;
328 	ptp->dev.release = ptp_clock_release;
329 	dev_set_drvdata(&ptp->dev, ptp);
330 	dev_set_name(&ptp->dev, "ptp%d", ptp->index);
331 
332 	/* Create a posix clock and link it to the device. */
333 	err = posix_clock_register(&ptp->clock, &ptp->dev);
334 	if (err) {
335 		if (ptp->pps_source)
336 			pps_unregister_source(ptp->pps_source);
337 
338 		if (ptp->kworker)
339 			kthread_destroy_worker(ptp->kworker);
340 
341 		put_device(&ptp->dev);
342 
343 		pr_err("failed to create posix clock\n");
344 		return ERR_PTR(err);
345 	}
346 
347 	/* Debugfs initialization */
348 	snprintf(debugfsname, sizeof(debugfsname), "ptp%d", ptp->index);
349 	ptp->debugfs_root = debugfs_create_dir(debugfsname, NULL);
350 
351 	return ptp;
352 
353 no_pps:
354 	ptp_cleanup_pin_groups(ptp);
355 no_pin_groups:
356 	kfree(ptp->vclock_index);
357 no_mem_for_vclocks:
358 	if (ptp->kworker)
359 		kthread_destroy_worker(ptp->kworker);
360 kworker_err:
361 	mutex_destroy(&ptp->pincfg_mux);
362 	mutex_destroy(&ptp->n_vclocks_mux);
363 	bitmap_free(queue->mask);
364 no_memory_bitmap:
365 	list_del(&queue->qlist);
366 	kfree(queue);
367 no_memory_queue:
368 	ida_free(&ptp_clocks_map, index);
369 no_slot:
370 	kfree(ptp);
371 no_memory:
372 	return ERR_PTR(err);
373 }
374 EXPORT_SYMBOL(ptp_clock_register);
375 
376 static int unregister_vclock(struct device *dev, void *data)
377 {
378 	struct ptp_clock *ptp = dev_get_drvdata(dev);
379 
380 	ptp_vclock_unregister(info_to_vclock(ptp->info));
381 	return 0;
382 }
383 
384 int ptp_clock_unregister(struct ptp_clock *ptp)
385 {
386 	if (ptp_vclock_in_use(ptp)) {
387 		device_for_each_child(&ptp->dev, NULL, unregister_vclock);
388 	}
389 
390 	ptp->defunct = 1;
391 	wake_up_interruptible(&ptp->tsev_wq);
392 
393 	if (ptp->kworker) {
394 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
395 		kthread_destroy_worker(ptp->kworker);
396 	}
397 
398 	/* Release the clock's resources. */
399 	if (ptp->pps_source)
400 		pps_unregister_source(ptp->pps_source);
401 
402 	posix_clock_unregister(&ptp->clock);
403 
404 	return 0;
405 }
406 EXPORT_SYMBOL(ptp_clock_unregister);
407 
408 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
409 {
410 	struct timestamp_event_queue *tsevq;
411 	struct pps_event_time evt;
412 	unsigned long flags;
413 
414 	switch (event->type) {
415 
416 	case PTP_CLOCK_ALARM:
417 		break;
418 
419 	case PTP_CLOCK_EXTTS:
420 		/* Enqueue timestamp on selected queues */
421 		spin_lock_irqsave(&ptp->tsevqs_lock, flags);
422 		list_for_each_entry(tsevq, &ptp->tsevqs, qlist) {
423 			if (test_bit((unsigned int)event->index, tsevq->mask))
424 				enqueue_external_timestamp(tsevq, event);
425 		}
426 		spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
427 		wake_up_interruptible(&ptp->tsev_wq);
428 		break;
429 
430 	case PTP_CLOCK_PPS:
431 		pps_get_ts(&evt);
432 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
433 		break;
434 
435 	case PTP_CLOCK_PPSUSR:
436 		pps_event(ptp->pps_source, &event->pps_times,
437 			  PTP_PPS_EVENT, NULL);
438 		break;
439 	}
440 }
441 EXPORT_SYMBOL(ptp_clock_event);
442 
443 int ptp_clock_index(struct ptp_clock *ptp)
444 {
445 	return ptp->index;
446 }
447 EXPORT_SYMBOL(ptp_clock_index);
448 
449 int ptp_find_pin(struct ptp_clock *ptp,
450 		 enum ptp_pin_function func, unsigned int chan)
451 {
452 	struct ptp_pin_desc *pin = NULL;
453 	int i;
454 
455 	for (i = 0; i < ptp->info->n_pins; i++) {
456 		if (ptp->info->pin_config[i].func == func &&
457 		    ptp->info->pin_config[i].chan == chan) {
458 			pin = &ptp->info->pin_config[i];
459 			break;
460 		}
461 	}
462 
463 	return pin ? i : -1;
464 }
465 EXPORT_SYMBOL(ptp_find_pin);
466 
467 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
468 			  enum ptp_pin_function func, unsigned int chan)
469 {
470 	int result;
471 
472 	mutex_lock(&ptp->pincfg_mux);
473 
474 	result = ptp_find_pin(ptp, func, chan);
475 
476 	mutex_unlock(&ptp->pincfg_mux);
477 
478 	return result;
479 }
480 EXPORT_SYMBOL(ptp_find_pin_unlocked);
481 
482 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
483 {
484 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
485 }
486 EXPORT_SYMBOL(ptp_schedule_worker);
487 
488 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
489 {
490 	kthread_cancel_delayed_work_sync(&ptp->aux_work);
491 }
492 EXPORT_SYMBOL(ptp_cancel_worker_sync);
493 
494 /* module operations */
495 
496 static void __exit ptp_exit(void)
497 {
498 	class_destroy(ptp_class);
499 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
500 	ida_destroy(&ptp_clocks_map);
501 }
502 
503 static int __init ptp_init(void)
504 {
505 	int err;
506 
507 	ptp_class = class_create("ptp");
508 	if (IS_ERR(ptp_class)) {
509 		pr_err("ptp: failed to allocate class\n");
510 		return PTR_ERR(ptp_class);
511 	}
512 
513 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
514 	if (err < 0) {
515 		pr_err("ptp: failed to allocate device region\n");
516 		goto no_region;
517 	}
518 
519 	ptp_class->dev_groups = ptp_groups;
520 	pr_info("PTP clock support registered\n");
521 	return 0;
522 
523 no_region:
524 	class_destroy(ptp_class);
525 	return err;
526 }
527 
528 subsys_initcall(ptp_init);
529 module_exit(ptp_exit);
530 
531 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
532 MODULE_DESCRIPTION("PTP clocks support");
533 MODULE_LICENSE("GPL");
534