xref: /linux/drivers/ptp/ptp_clock.c (revision 6f19b2c136d98a84d79030b53e23d405edfdc783) 
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 	tsevq = list_first_entry(&ptp->tsevqs, struct timestamp_event_queue,
183 				 qlist);
184 	spin_lock_irqsave(&tsevq->lock, flags);
185 	list_del(&tsevq->qlist);
186 	spin_unlock_irqrestore(&tsevq->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[8];
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 	queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL);
251 	if (!queue->mask)
252 		goto no_memory_bitmap;
253 	bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS);
254 	spin_lock_init(&queue->lock);
255 	mutex_init(&ptp->pincfg_mux);
256 	mutex_init(&ptp->n_vclocks_mux);
257 	init_waitqueue_head(&ptp->tsev_wq);
258 
259 	if (ptp->info->getcycles64 || ptp->info->getcyclesx64) {
260 		ptp->has_cycles = true;
261 		if (!ptp->info->getcycles64 && ptp->info->getcyclesx64)
262 			ptp->info->getcycles64 = ptp_getcycles64;
263 	} else {
264 		/* Free running cycle counter not supported, use time. */
265 		ptp->info->getcycles64 = ptp_getcycles64;
266 
267 		if (ptp->info->gettimex64)
268 			ptp->info->getcyclesx64 = ptp->info->gettimex64;
269 
270 		if (ptp->info->getcrosststamp)
271 			ptp->info->getcrosscycles = ptp->info->getcrosststamp;
272 	}
273 
274 	if (ptp->info->do_aux_work) {
275 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
276 		ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
277 		if (IS_ERR(ptp->kworker)) {
278 			err = PTR_ERR(ptp->kworker);
279 			pr_err("failed to create ptp aux_worker %d\n", err);
280 			goto kworker_err;
281 		}
282 	}
283 
284 	/* PTP virtual clock is being registered under physical clock */
285 	if (parent && parent->class && parent->class->name &&
286 	    strcmp(parent->class->name, "ptp") == 0)
287 		ptp->is_virtual_clock = true;
288 
289 	if (!ptp->is_virtual_clock) {
290 		ptp->max_vclocks = PTP_DEFAULT_MAX_VCLOCKS;
291 
292 		size = sizeof(int) * ptp->max_vclocks;
293 		ptp->vclock_index = kzalloc(size, GFP_KERNEL);
294 		if (!ptp->vclock_index) {
295 			err = -ENOMEM;
296 			goto no_mem_for_vclocks;
297 		}
298 	}
299 
300 	err = ptp_populate_pin_groups(ptp);
301 	if (err)
302 		goto no_pin_groups;
303 
304 	/* Register a new PPS source. */
305 	if (info->pps) {
306 		struct pps_source_info pps;
307 		memset(&pps, 0, sizeof(pps));
308 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
309 		pps.mode = PTP_PPS_MODE;
310 		pps.owner = info->owner;
311 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
312 		if (IS_ERR(ptp->pps_source)) {
313 			err = PTR_ERR(ptp->pps_source);
314 			pr_err("failed to register pps source\n");
315 			goto no_pps;
316 		}
317 		ptp->pps_source->lookup_cookie = ptp;
318 	}
319 
320 	/* Initialize a new device of our class in our clock structure. */
321 	device_initialize(&ptp->dev);
322 	ptp->dev.devt = ptp->devid;
323 	ptp->dev.class = ptp_class;
324 	ptp->dev.parent = parent;
325 	ptp->dev.groups = ptp->pin_attr_groups;
326 	ptp->dev.release = ptp_clock_release;
327 	dev_set_drvdata(&ptp->dev, ptp);
328 	dev_set_name(&ptp->dev, "ptp%d", ptp->index);
329 
330 	/* Create a posix clock and link it to the device. */
331 	err = posix_clock_register(&ptp->clock, &ptp->dev);
332 	if (err) {
333 		if (ptp->pps_source)
334 			pps_unregister_source(ptp->pps_source);
335 
336 		if (ptp->kworker)
337 			kthread_destroy_worker(ptp->kworker);
338 
339 		put_device(&ptp->dev);
340 
341 		pr_err("failed to create posix clock\n");
342 		return ERR_PTR(err);
343 	}
344 
345 	/* Debugfs initialization */
346 	sprintf(debugfsname, "ptp%d", ptp->index);
347 	ptp->debugfs_root = debugfs_create_dir(debugfsname, NULL);
348 
349 	return ptp;
350 
351 no_pps:
352 	ptp_cleanup_pin_groups(ptp);
353 no_pin_groups:
354 	kfree(ptp->vclock_index);
355 no_mem_for_vclocks:
356 	if (ptp->kworker)
357 		kthread_destroy_worker(ptp->kworker);
358 kworker_err:
359 	mutex_destroy(&ptp->pincfg_mux);
360 	mutex_destroy(&ptp->n_vclocks_mux);
361 	bitmap_free(queue->mask);
362 no_memory_bitmap:
363 	list_del(&queue->qlist);
364 	kfree(queue);
365 no_memory_queue:
366 	ida_free(&ptp_clocks_map, index);
367 no_slot:
368 	kfree(ptp);
369 no_memory:
370 	return ERR_PTR(err);
371 }
372 EXPORT_SYMBOL(ptp_clock_register);
373 
374 static int unregister_vclock(struct device *dev, void *data)
375 {
376 	struct ptp_clock *ptp = dev_get_drvdata(dev);
377 
378 	ptp_vclock_unregister(info_to_vclock(ptp->info));
379 	return 0;
380 }
381 
382 int ptp_clock_unregister(struct ptp_clock *ptp)
383 {
384 	if (ptp_vclock_in_use(ptp)) {
385 		device_for_each_child(&ptp->dev, NULL, unregister_vclock);
386 	}
387 
388 	ptp->defunct = 1;
389 	wake_up_interruptible(&ptp->tsev_wq);
390 
391 	if (ptp->kworker) {
392 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
393 		kthread_destroy_worker(ptp->kworker);
394 	}
395 
396 	/* Release the clock's resources. */
397 	if (ptp->pps_source)
398 		pps_unregister_source(ptp->pps_source);
399 
400 	posix_clock_unregister(&ptp->clock);
401 
402 	return 0;
403 }
404 EXPORT_SYMBOL(ptp_clock_unregister);
405 
406 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
407 {
408 	struct timestamp_event_queue *tsevq;
409 	struct pps_event_time evt;
410 
411 	switch (event->type) {
412 
413 	case PTP_CLOCK_ALARM:
414 		break;
415 
416 	case PTP_CLOCK_EXTTS:
417 		/* Enqueue timestamp on selected queues */
418 		list_for_each_entry(tsevq, &ptp->tsevqs, qlist) {
419 			if (test_bit((unsigned int)event->index, tsevq->mask))
420 				enqueue_external_timestamp(tsevq, event);
421 		}
422 		wake_up_interruptible(&ptp->tsev_wq);
423 		break;
424 
425 	case PTP_CLOCK_PPS:
426 		pps_get_ts(&evt);
427 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
428 		break;
429 
430 	case PTP_CLOCK_PPSUSR:
431 		pps_event(ptp->pps_source, &event->pps_times,
432 			  PTP_PPS_EVENT, NULL);
433 		break;
434 	}
435 }
436 EXPORT_SYMBOL(ptp_clock_event);
437 
438 int ptp_clock_index(struct ptp_clock *ptp)
439 {
440 	return ptp->index;
441 }
442 EXPORT_SYMBOL(ptp_clock_index);
443 
444 int ptp_find_pin(struct ptp_clock *ptp,
445 		 enum ptp_pin_function func, unsigned int chan)
446 {
447 	struct ptp_pin_desc *pin = NULL;
448 	int i;
449 
450 	for (i = 0; i < ptp->info->n_pins; i++) {
451 		if (ptp->info->pin_config[i].func == func &&
452 		    ptp->info->pin_config[i].chan == chan) {
453 			pin = &ptp->info->pin_config[i];
454 			break;
455 		}
456 	}
457 
458 	return pin ? i : -1;
459 }
460 EXPORT_SYMBOL(ptp_find_pin);
461 
462 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
463 			  enum ptp_pin_function func, unsigned int chan)
464 {
465 	int result;
466 
467 	mutex_lock(&ptp->pincfg_mux);
468 
469 	result = ptp_find_pin(ptp, func, chan);
470 
471 	mutex_unlock(&ptp->pincfg_mux);
472 
473 	return result;
474 }
475 EXPORT_SYMBOL(ptp_find_pin_unlocked);
476 
477 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
478 {
479 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
480 }
481 EXPORT_SYMBOL(ptp_schedule_worker);
482 
483 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
484 {
485 	kthread_cancel_delayed_work_sync(&ptp->aux_work);
486 }
487 EXPORT_SYMBOL(ptp_cancel_worker_sync);
488 
489 /* module operations */
490 
491 static void __exit ptp_exit(void)
492 {
493 	class_destroy(ptp_class);
494 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
495 	ida_destroy(&ptp_clocks_map);
496 }
497 
498 static int __init ptp_init(void)
499 {
500 	int err;
501 
502 	ptp_class = class_create("ptp");
503 	if (IS_ERR(ptp_class)) {
504 		pr_err("ptp: failed to allocate class\n");
505 		return PTR_ERR(ptp_class);
506 	}
507 
508 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
509 	if (err < 0) {
510 		pr_err("ptp: failed to allocate device region\n");
511 		goto no_region;
512 	}
513 
514 	ptp_class->dev_groups = ptp_groups;
515 	pr_info("PTP clock support registered\n");
516 	return 0;
517 
518 no_region:
519 	class_destroy(ptp_class);
520 	return err;
521 }
522 
523 subsys_initcall(ptp_init);
524 module_exit(ptp_exit);
525 
526 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
527 MODULE_DESCRIPTION("PTP clocks support");
528 MODULE_LICENSE("GPL");
529