xref: /linux/drivers/ptp/ptp_clock.c (revision c48a7c44a1d02516309015b6134c9bb982e17008) 
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 	if (!queue_free(queue))
61 		queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
62 
63 	queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;
64 
65 	spin_unlock_irqrestore(&queue->lock, flags);
66 }
67 
68 /* posix clock implementation */
69 
70 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
71 {
72 	tp->tv_sec = 0;
73 	tp->tv_nsec = 1;
74 	return 0;
75 }
76 
77 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
78 {
79 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
80 
81 	if (ptp_clock_freerun(ptp)) {
82 		pr_err("ptp: physical clock is free running\n");
83 		return -EBUSY;
84 	}
85 
86 	return  ptp->info->settime64(ptp->info, tp);
87 }
88 
89 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
90 {
91 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
92 	int err;
93 
94 	if (ptp->info->gettimex64)
95 		err = ptp->info->gettimex64(ptp->info, tp, NULL);
96 	else
97 		err = ptp->info->gettime64(ptp->info, tp);
98 	return err;
99 }
100 
101 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
102 {
103 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
104 	struct ptp_clock_info *ops;
105 	int err = -EOPNOTSUPP;
106 
107 	if (ptp_clock_freerun(ptp)) {
108 		pr_err("ptp: physical clock is free running\n");
109 		return -EBUSY;
110 	}
111 
112 	ops = ptp->info;
113 
114 	if (tx->modes & ADJ_SETOFFSET) {
115 		struct timespec64 ts;
116 		ktime_t kt;
117 		s64 delta;
118 
119 		ts.tv_sec  = tx->time.tv_sec;
120 		ts.tv_nsec = tx->time.tv_usec;
121 
122 		if (!(tx->modes & ADJ_NANO))
123 			ts.tv_nsec *= 1000;
124 
125 		if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
126 			return -EINVAL;
127 
128 		kt = timespec64_to_ktime(ts);
129 		delta = ktime_to_ns(kt);
130 		err = ops->adjtime(ops, delta);
131 	} else if (tx->modes & ADJ_FREQUENCY) {
132 		long ppb = scaled_ppm_to_ppb(tx->freq);
133 		if (ppb > ops->max_adj || ppb < -ops->max_adj)
134 			return -ERANGE;
135 		err = ops->adjfine(ops, tx->freq);
136 		ptp->dialed_frequency = tx->freq;
137 	} else if (tx->modes & ADJ_OFFSET) {
138 		if (ops->adjphase) {
139 			s32 max_phase_adj = ops->getmaxphase(ops);
140 			s32 offset = tx->offset;
141 
142 			if (!(tx->modes & ADJ_NANO))
143 				offset *= NSEC_PER_USEC;
144 
145 			if (offset > max_phase_adj || offset < -max_phase_adj)
146 				return -ERANGE;
147 
148 			err = ops->adjphase(ops, offset);
149 		}
150 	} else if (tx->modes == 0) {
151 		tx->freq = ptp->dialed_frequency;
152 		err = 0;
153 	}
154 
155 	return err;
156 }
157 
158 static struct posix_clock_operations ptp_clock_ops = {
159 	.owner		= THIS_MODULE,
160 	.clock_adjtime	= ptp_clock_adjtime,
161 	.clock_gettime	= ptp_clock_gettime,
162 	.clock_getres	= ptp_clock_getres,
163 	.clock_settime	= ptp_clock_settime,
164 	.ioctl		= ptp_ioctl,
165 	.open		= ptp_open,
166 	.release	= ptp_release,
167 	.poll		= ptp_poll,
168 	.read		= ptp_read,
169 };
170 
171 static void ptp_clock_release(struct device *dev)
172 {
173 	struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
174 	struct timestamp_event_queue *tsevq;
175 	unsigned long flags;
176 
177 	ptp_cleanup_pin_groups(ptp);
178 	kfree(ptp->vclock_index);
179 	mutex_destroy(&ptp->pincfg_mux);
180 	mutex_destroy(&ptp->n_vclocks_mux);
181 	/* Delete first entry */
182 	spin_lock_irqsave(&ptp->tsevqs_lock, flags);
183 	tsevq = list_first_entry(&ptp->tsevqs, struct timestamp_event_queue,
184 				 qlist);
185 	list_del(&tsevq->qlist);
186 	spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
187 	bitmap_free(tsevq->mask);
188 	kfree(tsevq);
189 	debugfs_remove(ptp->debugfs_root);
190 	ida_free(&ptp_clocks_map, ptp->index);
191 	kfree(ptp);
192 }
193 
194 static int ptp_getcycles64(struct ptp_clock_info *info, struct timespec64 *ts)
195 {
196 	if (info->getcyclesx64)
197 		return info->getcyclesx64(info, ts, NULL);
198 	else
199 		return info->gettime64(info, ts);
200 }
201 
202 static void ptp_aux_kworker(struct kthread_work *work)
203 {
204 	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
205 					     aux_work.work);
206 	struct ptp_clock_info *info = ptp->info;
207 	long delay;
208 
209 	delay = info->do_aux_work(info);
210 
211 	if (delay >= 0)
212 		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
213 }
214 
215 /* public interface */
216 
217 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
218 				     struct device *parent)
219 {
220 	struct ptp_clock *ptp;
221 	struct timestamp_event_queue *queue = NULL;
222 	int err = 0, index, major = MAJOR(ptp_devt);
223 	char debugfsname[16];
224 	size_t size;
225 
226 	if (info->n_alarm > PTP_MAX_ALARMS)
227 		return ERR_PTR(-EINVAL);
228 
229 	/* Initialize a clock structure. */
230 	err = -ENOMEM;
231 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
232 	if (ptp == NULL)
233 		goto no_memory;
234 
235 	index = ida_alloc_max(&ptp_clocks_map, MINORMASK, GFP_KERNEL);
236 	if (index < 0) {
237 		err = index;
238 		goto no_slot;
239 	}
240 
241 	ptp->clock.ops = ptp_clock_ops;
242 	ptp->info = info;
243 	ptp->devid = MKDEV(major, index);
244 	ptp->index = index;
245 	INIT_LIST_HEAD(&ptp->tsevqs);
246 	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
247 	if (!queue)
248 		goto no_memory_queue;
249 	list_add_tail(&queue->qlist, &ptp->tsevqs);
250 	spin_lock_init(&ptp->tsevqs_lock);
251 	queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL);
252 	if (!queue->mask)
253 		goto no_memory_bitmap;
254 	bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS);
255 	spin_lock_init(&queue->lock);
256 	mutex_init(&ptp->pincfg_mux);
257 	mutex_init(&ptp->n_vclocks_mux);
258 	init_waitqueue_head(&ptp->tsev_wq);
259 
260 	if (ptp->info->getcycles64 || ptp->info->getcyclesx64) {
261 		ptp->has_cycles = true;
262 		if (!ptp->info->getcycles64 && ptp->info->getcyclesx64)
263 			ptp->info->getcycles64 = ptp_getcycles64;
264 	} else {
265 		/* Free running cycle counter not supported, use time. */
266 		ptp->info->getcycles64 = ptp_getcycles64;
267 
268 		if (ptp->info->gettimex64)
269 			ptp->info->getcyclesx64 = ptp->info->gettimex64;
270 
271 		if (ptp->info->getcrosststamp)
272 			ptp->info->getcrosscycles = ptp->info->getcrosststamp;
273 	}
274 
275 	if (ptp->info->do_aux_work) {
276 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
277 		ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
278 		if (IS_ERR(ptp->kworker)) {
279 			err = PTR_ERR(ptp->kworker);
280 			pr_err("failed to create ptp aux_worker %d\n", err);
281 			goto kworker_err;
282 		}
283 	}
284 
285 	/* PTP virtual clock is being registered under physical clock */
286 	if (parent && parent->class && parent->class->name &&
287 	    strcmp(parent->class->name, "ptp") == 0)
288 		ptp->is_virtual_clock = true;
289 
290 	if (!ptp->is_virtual_clock) {
291 		ptp->max_vclocks = PTP_DEFAULT_MAX_VCLOCKS;
292 
293 		size = sizeof(int) * ptp->max_vclocks;
294 		ptp->vclock_index = kzalloc(size, GFP_KERNEL);
295 		if (!ptp->vclock_index) {
296 			err = -ENOMEM;
297 			goto no_mem_for_vclocks;
298 		}
299 	}
300 
301 	err = ptp_populate_pin_groups(ptp);
302 	if (err)
303 		goto no_pin_groups;
304 
305 	/* Register a new PPS source. */
306 	if (info->pps) {
307 		struct pps_source_info pps;
308 		memset(&pps, 0, sizeof(pps));
309 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
310 		pps.mode = PTP_PPS_MODE;
311 		pps.owner = info->owner;
312 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
313 		if (IS_ERR(ptp->pps_source)) {
314 			err = PTR_ERR(ptp->pps_source);
315 			pr_err("failed to register pps source\n");
316 			goto no_pps;
317 		}
318 		ptp->pps_source->lookup_cookie = ptp;
319 	}
320 
321 	/* Initialize a new device of our class in our clock structure. */
322 	device_initialize(&ptp->dev);
323 	ptp->dev.devt = ptp->devid;
324 	ptp->dev.class = ptp_class;
325 	ptp->dev.parent = parent;
326 	ptp->dev.groups = ptp->pin_attr_groups;
327 	ptp->dev.release = ptp_clock_release;
328 	dev_set_drvdata(&ptp->dev, ptp);
329 	dev_set_name(&ptp->dev, "ptp%d", ptp->index);
330 
331 	/* Create a posix clock and link it to the device. */
332 	err = posix_clock_register(&ptp->clock, &ptp->dev);
333 	if (err) {
334 		if (ptp->pps_source)
335 			pps_unregister_source(ptp->pps_source);
336 
337 		if (ptp->kworker)
338 			kthread_destroy_worker(ptp->kworker);
339 
340 		put_device(&ptp->dev);
341 
342 		pr_err("failed to create posix clock\n");
343 		return ERR_PTR(err);
344 	}
345 
346 	/* Debugfs initialization */
347 	snprintf(debugfsname, sizeof(debugfsname), "ptp%d", ptp->index);
348 	ptp->debugfs_root = debugfs_create_dir(debugfsname, NULL);
349 
350 	return ptp;
351 
352 no_pps:
353 	ptp_cleanup_pin_groups(ptp);
354 no_pin_groups:
355 	kfree(ptp->vclock_index);
356 no_mem_for_vclocks:
357 	if (ptp->kworker)
358 		kthread_destroy_worker(ptp->kworker);
359 kworker_err:
360 	mutex_destroy(&ptp->pincfg_mux);
361 	mutex_destroy(&ptp->n_vclocks_mux);
362 	bitmap_free(queue->mask);
363 no_memory_bitmap:
364 	list_del(&queue->qlist);
365 	kfree(queue);
366 no_memory_queue:
367 	ida_free(&ptp_clocks_map, index);
368 no_slot:
369 	kfree(ptp);
370 no_memory:
371 	return ERR_PTR(err);
372 }
373 EXPORT_SYMBOL(ptp_clock_register);
374 
375 static int unregister_vclock(struct device *dev, void *data)
376 {
377 	struct ptp_clock *ptp = dev_get_drvdata(dev);
378 
379 	ptp_vclock_unregister(info_to_vclock(ptp->info));
380 	return 0;
381 }
382 
383 int ptp_clock_unregister(struct ptp_clock *ptp)
384 {
385 	if (ptp_vclock_in_use(ptp)) {
386 		device_for_each_child(&ptp->dev, NULL, unregister_vclock);
387 	}
388 
389 	ptp->defunct = 1;
390 	wake_up_interruptible(&ptp->tsev_wq);
391 
392 	if (ptp->kworker) {
393 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
394 		kthread_destroy_worker(ptp->kworker);
395 	}
396 
397 	/* Release the clock's resources. */
398 	if (ptp->pps_source)
399 		pps_unregister_source(ptp->pps_source);
400 
401 	posix_clock_unregister(&ptp->clock);
402 
403 	return 0;
404 }
405 EXPORT_SYMBOL(ptp_clock_unregister);
406 
407 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
408 {
409 	struct timestamp_event_queue *tsevq;
410 	struct pps_event_time evt;
411 	unsigned long flags;
412 
413 	switch (event->type) {
414 
415 	case PTP_CLOCK_ALARM:
416 		break;
417 
418 	case PTP_CLOCK_EXTTS:
419 		/* Enqueue timestamp on selected queues */
420 		spin_lock_irqsave(&ptp->tsevqs_lock, flags);
421 		list_for_each_entry(tsevq, &ptp->tsevqs, qlist) {
422 			if (test_bit((unsigned int)event->index, tsevq->mask))
423 				enqueue_external_timestamp(tsevq, event);
424 		}
425 		spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
426 		wake_up_interruptible(&ptp->tsev_wq);
427 		break;
428 
429 	case PTP_CLOCK_PPS:
430 		pps_get_ts(&evt);
431 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
432 		break;
433 
434 	case PTP_CLOCK_PPSUSR:
435 		pps_event(ptp->pps_source, &event->pps_times,
436 			  PTP_PPS_EVENT, NULL);
437 		break;
438 	}
439 }
440 EXPORT_SYMBOL(ptp_clock_event);
441 
442 int ptp_clock_index(struct ptp_clock *ptp)
443 {
444 	return ptp->index;
445 }
446 EXPORT_SYMBOL(ptp_clock_index);
447 
448 int ptp_find_pin(struct ptp_clock *ptp,
449 		 enum ptp_pin_function func, unsigned int chan)
450 {
451 	struct ptp_pin_desc *pin = NULL;
452 	int i;
453 
454 	for (i = 0; i < ptp->info->n_pins; i++) {
455 		if (ptp->info->pin_config[i].func == func &&
456 		    ptp->info->pin_config[i].chan == chan) {
457 			pin = &ptp->info->pin_config[i];
458 			break;
459 		}
460 	}
461 
462 	return pin ? i : -1;
463 }
464 EXPORT_SYMBOL(ptp_find_pin);
465 
466 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
467 			  enum ptp_pin_function func, unsigned int chan)
468 {
469 	int result;
470 
471 	mutex_lock(&ptp->pincfg_mux);
472 
473 	result = ptp_find_pin(ptp, func, chan);
474 
475 	mutex_unlock(&ptp->pincfg_mux);
476 
477 	return result;
478 }
479 EXPORT_SYMBOL(ptp_find_pin_unlocked);
480 
481 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
482 {
483 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
484 }
485 EXPORT_SYMBOL(ptp_schedule_worker);
486 
487 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
488 {
489 	kthread_cancel_delayed_work_sync(&ptp->aux_work);
490 }
491 EXPORT_SYMBOL(ptp_cancel_worker_sync);
492 
493 /* module operations */
494 
495 static void __exit ptp_exit(void)
496 {
497 	class_destroy(ptp_class);
498 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
499 	ida_destroy(&ptp_clocks_map);
500 }
501 
502 static int __init ptp_init(void)
503 {
504 	int err;
505 
506 	ptp_class = class_create("ptp");
507 	if (IS_ERR(ptp_class)) {
508 		pr_err("ptp: failed to allocate class\n");
509 		return PTR_ERR(ptp_class);
510 	}
511 
512 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
513 	if (err < 0) {
514 		pr_err("ptp: failed to allocate device region\n");
515 		goto no_region;
516 	}
517 
518 	ptp_class->dev_groups = ptp_groups;
519 	pr_info("PTP clock support registered\n");
520 	return 0;
521 
522 no_region:
523 	class_destroy(ptp_class);
524 	return err;
525 }
526 
527 subsys_initcall(ptp_init);
528 module_exit(ptp_exit);
529 
530 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
531 MODULE_DESCRIPTION("PTP clocks support");
532 MODULE_LICENSE("GPL");
533