xref: /kernel/linux/linux-6.6/drivers/ptp/ptp_clock.c (revision 62306a36) 
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 <uapi/linux/sched/types.h>
19
20#include "ptp_private.h"
21
22#define PTP_MAX_ALARMS 4
23#define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT)
24#define PTP_PPS_EVENT PPS_CAPTUREASSERT
25#define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)
26
27struct class *ptp_class;
28
29/* private globals */
30
31static dev_t ptp_devt;
32
33static DEFINE_IDA(ptp_clocks_map);
34
35/* time stamp event queue operations */
36
37static inline int queue_free(struct timestamp_event_queue *q)
38{
39	return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
40}
41
42static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
43				       struct ptp_clock_event *src)
44{
45	struct ptp_extts_event *dst;
46	unsigned long flags;
47	s64 seconds;
48	u32 remainder;
49
50	seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
51
52	spin_lock_irqsave(&queue->lock, flags);
53
54	dst = &queue->buf[queue->tail];
55	dst->index = src->index;
56	dst->t.sec = seconds;
57	dst->t.nsec = remainder;
58
59	/* Both WRITE_ONCE() are paired with READ_ONCE() in queue_cnt() */
60	if (!queue_free(queue))
61		WRITE_ONCE(queue->head, (queue->head + 1) % PTP_MAX_TIMESTAMPS);
62
63	WRITE_ONCE(queue->tail, (queue->tail + 1) % PTP_MAX_TIMESTAMPS);
64
65	spin_unlock_irqrestore(&queue->lock, flags);
66}
67
68/* posix clock implementation */
69
70static 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
77static 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
89static 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
101static 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
158static 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	.poll		= ptp_poll,
167	.read		= ptp_read,
168};
169
170static void ptp_clock_release(struct device *dev)
171{
172	struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
173
174	ptp_cleanup_pin_groups(ptp);
175	kfree(ptp->vclock_index);
176	mutex_destroy(&ptp->tsevq_mux);
177	mutex_destroy(&ptp->pincfg_mux);
178	mutex_destroy(&ptp->n_vclocks_mux);
179	ida_free(&ptp_clocks_map, ptp->index);
180	kfree(ptp);
181}
182
183static int ptp_getcycles64(struct ptp_clock_info *info, struct timespec64 *ts)
184{
185	if (info->getcyclesx64)
186		return info->getcyclesx64(info, ts, NULL);
187	else
188		return info->gettime64(info, ts);
189}
190
191static void ptp_aux_kworker(struct kthread_work *work)
192{
193	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
194					     aux_work.work);
195	struct ptp_clock_info *info = ptp->info;
196	long delay;
197
198	delay = info->do_aux_work(info);
199
200	if (delay >= 0)
201		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
202}
203
204/* public interface */
205
206struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
207				     struct device *parent)
208{
209	struct ptp_clock *ptp;
210	int err = 0, index, major = MAJOR(ptp_devt);
211	size_t size;
212
213	if (info->n_alarm > PTP_MAX_ALARMS)
214		return ERR_PTR(-EINVAL);
215
216	/* Initialize a clock structure. */
217	err = -ENOMEM;
218	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
219	if (ptp == NULL)
220		goto no_memory;
221
222	index = ida_alloc_max(&ptp_clocks_map, MINORMASK, GFP_KERNEL);
223	if (index < 0) {
224		err = index;
225		goto no_slot;
226	}
227
228	ptp->clock.ops = ptp_clock_ops;
229	ptp->info = info;
230	ptp->devid = MKDEV(major, index);
231	ptp->index = index;
232	spin_lock_init(&ptp->tsevq.lock);
233	mutex_init(&ptp->tsevq_mux);
234	mutex_init(&ptp->pincfg_mux);
235	mutex_init(&ptp->n_vclocks_mux);
236	init_waitqueue_head(&ptp->tsev_wq);
237
238	if (ptp->info->getcycles64 || ptp->info->getcyclesx64) {
239		ptp->has_cycles = true;
240		if (!ptp->info->getcycles64 && ptp->info->getcyclesx64)
241			ptp->info->getcycles64 = ptp_getcycles64;
242	} else {
243		/* Free running cycle counter not supported, use time. */
244		ptp->info->getcycles64 = ptp_getcycles64;
245
246		if (ptp->info->gettimex64)
247			ptp->info->getcyclesx64 = ptp->info->gettimex64;
248
249		if (ptp->info->getcrosststamp)
250			ptp->info->getcrosscycles = ptp->info->getcrosststamp;
251	}
252
253	if (ptp->info->do_aux_work) {
254		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
255		ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
256		if (IS_ERR(ptp->kworker)) {
257			err = PTR_ERR(ptp->kworker);
258			pr_err("failed to create ptp aux_worker %d\n", err);
259			goto kworker_err;
260		}
261	}
262
263	/* PTP virtual clock is being registered under physical clock */
264	if (parent && parent->class && parent->class->name &&
265	    strcmp(parent->class->name, "ptp") == 0)
266		ptp->is_virtual_clock = true;
267
268	if (!ptp->is_virtual_clock) {
269		ptp->max_vclocks = PTP_DEFAULT_MAX_VCLOCKS;
270
271		size = sizeof(int) * ptp->max_vclocks;
272		ptp->vclock_index = kzalloc(size, GFP_KERNEL);
273		if (!ptp->vclock_index) {
274			err = -ENOMEM;
275			goto no_mem_for_vclocks;
276		}
277	}
278
279	err = ptp_populate_pin_groups(ptp);
280	if (err)
281		goto no_pin_groups;
282
283	/* Register a new PPS source. */
284	if (info->pps) {
285		struct pps_source_info pps;
286		memset(&pps, 0, sizeof(pps));
287		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
288		pps.mode = PTP_PPS_MODE;
289		pps.owner = info->owner;
290		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
291		if (IS_ERR(ptp->pps_source)) {
292			err = PTR_ERR(ptp->pps_source);
293			pr_err("failed to register pps source\n");
294			goto no_pps;
295		}
296		ptp->pps_source->lookup_cookie = ptp;
297	}
298
299	/* Initialize a new device of our class in our clock structure. */
300	device_initialize(&ptp->dev);
301	ptp->dev.devt = ptp->devid;
302	ptp->dev.class = ptp_class;
303	ptp->dev.parent = parent;
304	ptp->dev.groups = ptp->pin_attr_groups;
305	ptp->dev.release = ptp_clock_release;
306	dev_set_drvdata(&ptp->dev, ptp);
307	dev_set_name(&ptp->dev, "ptp%d", ptp->index);
308
309	/* Create a posix clock and link it to the device. */
310	err = posix_clock_register(&ptp->clock, &ptp->dev);
311	if (err) {
312		if (ptp->pps_source)
313			pps_unregister_source(ptp->pps_source);
314
315		if (ptp->kworker)
316			kthread_destroy_worker(ptp->kworker);
317
318		put_device(&ptp->dev);
319
320		pr_err("failed to create posix clock\n");
321		return ERR_PTR(err);
322	}
323
324	return ptp;
325
326no_pps:
327	ptp_cleanup_pin_groups(ptp);
328no_pin_groups:
329	kfree(ptp->vclock_index);
330no_mem_for_vclocks:
331	if (ptp->kworker)
332		kthread_destroy_worker(ptp->kworker);
333kworker_err:
334	mutex_destroy(&ptp->tsevq_mux);
335	mutex_destroy(&ptp->pincfg_mux);
336	mutex_destroy(&ptp->n_vclocks_mux);
337	ida_free(&ptp_clocks_map, index);
338no_slot:
339	kfree(ptp);
340no_memory:
341	return ERR_PTR(err);
342}
343EXPORT_SYMBOL(ptp_clock_register);
344
345static int unregister_vclock(struct device *dev, void *data)
346{
347	struct ptp_clock *ptp = dev_get_drvdata(dev);
348
349	ptp_vclock_unregister(info_to_vclock(ptp->info));
350	return 0;
351}
352
353int ptp_clock_unregister(struct ptp_clock *ptp)
354{
355	if (ptp_vclock_in_use(ptp)) {
356		device_for_each_child(&ptp->dev, NULL, unregister_vclock);
357	}
358
359	ptp->defunct = 1;
360	wake_up_interruptible(&ptp->tsev_wq);
361
362	if (ptp->kworker) {
363		kthread_cancel_delayed_work_sync(&ptp->aux_work);
364		kthread_destroy_worker(ptp->kworker);
365	}
366
367	/* Release the clock's resources. */
368	if (ptp->pps_source)
369		pps_unregister_source(ptp->pps_source);
370
371	posix_clock_unregister(&ptp->clock);
372
373	return 0;
374}
375EXPORT_SYMBOL(ptp_clock_unregister);
376
377void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
378{
379	struct pps_event_time evt;
380
381	switch (event->type) {
382
383	case PTP_CLOCK_ALARM:
384		break;
385
386	case PTP_CLOCK_EXTTS:
387		enqueue_external_timestamp(&ptp->tsevq, event);
388		wake_up_interruptible(&ptp->tsev_wq);
389		break;
390
391	case PTP_CLOCK_PPS:
392		pps_get_ts(&evt);
393		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
394		break;
395
396	case PTP_CLOCK_PPSUSR:
397		pps_event(ptp->pps_source, &event->pps_times,
398			  PTP_PPS_EVENT, NULL);
399		break;
400	}
401}
402EXPORT_SYMBOL(ptp_clock_event);
403
404int ptp_clock_index(struct ptp_clock *ptp)
405{
406	return ptp->index;
407}
408EXPORT_SYMBOL(ptp_clock_index);
409
410int ptp_find_pin(struct ptp_clock *ptp,
411		 enum ptp_pin_function func, unsigned int chan)
412{
413	struct ptp_pin_desc *pin = NULL;
414	int i;
415
416	for (i = 0; i < ptp->info->n_pins; i++) {
417		if (ptp->info->pin_config[i].func == func &&
418		    ptp->info->pin_config[i].chan == chan) {
419			pin = &ptp->info->pin_config[i];
420			break;
421		}
422	}
423
424	return pin ? i : -1;
425}
426EXPORT_SYMBOL(ptp_find_pin);
427
428int ptp_find_pin_unlocked(struct ptp_clock *ptp,
429			  enum ptp_pin_function func, unsigned int chan)
430{
431	int result;
432
433	mutex_lock(&ptp->pincfg_mux);
434
435	result = ptp_find_pin(ptp, func, chan);
436
437	mutex_unlock(&ptp->pincfg_mux);
438
439	return result;
440}
441EXPORT_SYMBOL(ptp_find_pin_unlocked);
442
443int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
444{
445	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
446}
447EXPORT_SYMBOL(ptp_schedule_worker);
448
449void ptp_cancel_worker_sync(struct ptp_clock *ptp)
450{
451	kthread_cancel_delayed_work_sync(&ptp->aux_work);
452}
453EXPORT_SYMBOL(ptp_cancel_worker_sync);
454
455/* module operations */
456
457static void __exit ptp_exit(void)
458{
459	class_destroy(ptp_class);
460	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
461	ida_destroy(&ptp_clocks_map);
462}
463
464static int __init ptp_init(void)
465{
466	int err;
467
468	ptp_class = class_create("ptp");
469	if (IS_ERR(ptp_class)) {
470		pr_err("ptp: failed to allocate class\n");
471		return PTR_ERR(ptp_class);
472	}
473
474	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
475	if (err < 0) {
476		pr_err("ptp: failed to allocate device region\n");
477		goto no_region;
478	}
479
480	ptp_class->dev_groups = ptp_groups;
481	pr_info("PTP clock support registered\n");
482	return 0;
483
484no_region:
485	class_destroy(ptp_class);
486	return err;
487}
488
489subsys_initcall(ptp_init);
490module_exit(ptp_exit);
491
492MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
493MODULE_DESCRIPTION("PTP clocks support");
494MODULE_LICENSE("GPL");
495