xref: /linux/drivers/ptp/ptp_clock.c (revision 1b0975ee3bdd3eb19a47371c26fd7ef8f7f6b599) 
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 
27 struct class *ptp_class;
28 
29 /* private globals */
30 
31 static dev_t ptp_devt;
32 
33 static DEFINE_IDA(ptp_clocks_map);
34 
35 /* time stamp event queue operations */
36 
37 static inline int queue_free(struct timestamp_event_queue *q)
38 {
39 	return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
40 }
41 
42 static 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 	if (!queue_free(queue))
60 		queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
61 
62 	queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;
63 
64 	spin_unlock_irqrestore(&queue->lock, flags);
65 }
66 
67 /* posix clock implementation */
68 
69 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
70 {
71 	tp->tv_sec = 0;
72 	tp->tv_nsec = 1;
73 	return 0;
74 }
75 
76 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
77 {
78 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
79 
80 	if (ptp_clock_freerun(ptp)) {
81 		pr_err("ptp: physical clock is free running\n");
82 		return -EBUSY;
83 	}
84 
85 	return  ptp->info->settime64(ptp->info, tp);
86 }
87 
88 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
89 {
90 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
91 	int err;
92 
93 	if (ptp->info->gettimex64)
94 		err = ptp->info->gettimex64(ptp->info, tp, NULL);
95 	else
96 		err = ptp->info->gettime64(ptp->info, tp);
97 	return err;
98 }
99 
100 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
101 {
102 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
103 	struct ptp_clock_info *ops;
104 	int err = -EOPNOTSUPP;
105 
106 	if (ptp_clock_freerun(ptp)) {
107 		pr_err("ptp: physical clock is free running\n");
108 		return -EBUSY;
109 	}
110 
111 	ops = ptp->info;
112 
113 	if (tx->modes & ADJ_SETOFFSET) {
114 		struct timespec64 ts;
115 		ktime_t kt;
116 		s64 delta;
117 
118 		ts.tv_sec  = tx->time.tv_sec;
119 		ts.tv_nsec = tx->time.tv_usec;
120 
121 		if (!(tx->modes & ADJ_NANO))
122 			ts.tv_nsec *= 1000;
123 
124 		if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
125 			return -EINVAL;
126 
127 		kt = timespec64_to_ktime(ts);
128 		delta = ktime_to_ns(kt);
129 		err = ops->adjtime(ops, delta);
130 	} else if (tx->modes & ADJ_FREQUENCY) {
131 		long ppb = scaled_ppm_to_ppb(tx->freq);
132 		if (ppb > ops->max_adj || ppb < -ops->max_adj)
133 			return -ERANGE;
134 		err = ops->adjfine(ops, tx->freq);
135 		ptp->dialed_frequency = tx->freq;
136 	} else if (tx->modes & ADJ_OFFSET) {
137 		if (ops->adjphase) {
138 			s32 max_phase_adj = ops->getmaxphase(ops);
139 			s32 offset = tx->offset;
140 
141 			if (!(tx->modes & ADJ_NANO))
142 				offset *= NSEC_PER_USEC;
143 
144 			if (offset > max_phase_adj || offset < -max_phase_adj)
145 				return -ERANGE;
146 
147 			err = ops->adjphase(ops, offset);
148 		}
149 	} else if (tx->modes == 0) {
150 		tx->freq = ptp->dialed_frequency;
151 		err = 0;
152 	}
153 
154 	return err;
155 }
156 
157 static struct posix_clock_operations ptp_clock_ops = {
158 	.owner		= THIS_MODULE,
159 	.clock_adjtime	= ptp_clock_adjtime,
160 	.clock_gettime	= ptp_clock_gettime,
161 	.clock_getres	= ptp_clock_getres,
162 	.clock_settime	= ptp_clock_settime,
163 	.ioctl		= ptp_ioctl,
164 	.open		= ptp_open,
165 	.poll		= ptp_poll,
166 	.read		= ptp_read,
167 };
168 
169 static void ptp_clock_release(struct device *dev)
170 {
171 	struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
172 
173 	ptp_cleanup_pin_groups(ptp);
174 	kfree(ptp->vclock_index);
175 	mutex_destroy(&ptp->tsevq_mux);
176 	mutex_destroy(&ptp->pincfg_mux);
177 	mutex_destroy(&ptp->n_vclocks_mux);
178 	ida_free(&ptp_clocks_map, ptp->index);
179 	kfree(ptp);
180 }
181 
182 static int ptp_getcycles64(struct ptp_clock_info *info, struct timespec64 *ts)
183 {
184 	if (info->getcyclesx64)
185 		return info->getcyclesx64(info, ts, NULL);
186 	else
187 		return info->gettime64(info, ts);
188 }
189 
190 static void ptp_aux_kworker(struct kthread_work *work)
191 {
192 	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
193 					     aux_work.work);
194 	struct ptp_clock_info *info = ptp->info;
195 	long delay;
196 
197 	delay = info->do_aux_work(info);
198 
199 	if (delay >= 0)
200 		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
201 }
202 
203 /* public interface */
204 
205 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
206 				     struct device *parent)
207 {
208 	struct ptp_clock *ptp;
209 	int err = 0, index, major = MAJOR(ptp_devt);
210 	size_t size;
211 
212 	if (info->n_alarm > PTP_MAX_ALARMS)
213 		return ERR_PTR(-EINVAL);
214 
215 	/* Initialize a clock structure. */
216 	err = -ENOMEM;
217 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
218 	if (ptp == NULL)
219 		goto no_memory;
220 
221 	index = ida_alloc_max(&ptp_clocks_map, MINORMASK, GFP_KERNEL);
222 	if (index < 0) {
223 		err = index;
224 		goto no_slot;
225 	}
226 
227 	ptp->clock.ops = ptp_clock_ops;
228 	ptp->info = info;
229 	ptp->devid = MKDEV(major, index);
230 	ptp->index = index;
231 	spin_lock_init(&ptp->tsevq.lock);
232 	mutex_init(&ptp->tsevq_mux);
233 	mutex_init(&ptp->pincfg_mux);
234 	mutex_init(&ptp->n_vclocks_mux);
235 	init_waitqueue_head(&ptp->tsev_wq);
236 
237 	if (ptp->info->getcycles64 || ptp->info->getcyclesx64) {
238 		ptp->has_cycles = true;
239 		if (!ptp->info->getcycles64 && ptp->info->getcyclesx64)
240 			ptp->info->getcycles64 = ptp_getcycles64;
241 	} else {
242 		/* Free running cycle counter not supported, use time. */
243 		ptp->info->getcycles64 = ptp_getcycles64;
244 
245 		if (ptp->info->gettimex64)
246 			ptp->info->getcyclesx64 = ptp->info->gettimex64;
247 
248 		if (ptp->info->getcrosststamp)
249 			ptp->info->getcrosscycles = ptp->info->getcrosststamp;
250 	}
251 
252 	if (ptp->info->do_aux_work) {
253 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
254 		ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
255 		if (IS_ERR(ptp->kworker)) {
256 			err = PTR_ERR(ptp->kworker);
257 			pr_err("failed to create ptp aux_worker %d\n", err);
258 			goto kworker_err;
259 		}
260 	}
261 
262 	/* PTP virtual clock is being registered under physical clock */
263 	if (parent && parent->class && parent->class->name &&
264 	    strcmp(parent->class->name, "ptp") == 0)
265 		ptp->is_virtual_clock = true;
266 
267 	if (!ptp->is_virtual_clock) {
268 		ptp->max_vclocks = PTP_DEFAULT_MAX_VCLOCKS;
269 
270 		size = sizeof(int) * ptp->max_vclocks;
271 		ptp->vclock_index = kzalloc(size, GFP_KERNEL);
272 		if (!ptp->vclock_index) {
273 			err = -ENOMEM;
274 			goto no_mem_for_vclocks;
275 		}
276 	}
277 
278 	err = ptp_populate_pin_groups(ptp);
279 	if (err)
280 		goto no_pin_groups;
281 
282 	/* Register a new PPS source. */
283 	if (info->pps) {
284 		struct pps_source_info pps;
285 		memset(&pps, 0, sizeof(pps));
286 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
287 		pps.mode = PTP_PPS_MODE;
288 		pps.owner = info->owner;
289 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
290 		if (IS_ERR(ptp->pps_source)) {
291 			err = PTR_ERR(ptp->pps_source);
292 			pr_err("failed to register pps source\n");
293 			goto no_pps;
294 		}
295 		ptp->pps_source->lookup_cookie = ptp;
296 	}
297 
298 	/* Initialize a new device of our class in our clock structure. */
299 	device_initialize(&ptp->dev);
300 	ptp->dev.devt = ptp->devid;
301 	ptp->dev.class = ptp_class;
302 	ptp->dev.parent = parent;
303 	ptp->dev.groups = ptp->pin_attr_groups;
304 	ptp->dev.release = ptp_clock_release;
305 	dev_set_drvdata(&ptp->dev, ptp);
306 	dev_set_name(&ptp->dev, "ptp%d", ptp->index);
307 
308 	/* Create a posix clock and link it to the device. */
309 	err = posix_clock_register(&ptp->clock, &ptp->dev);
310 	if (err) {
311 		if (ptp->pps_source)
312 			pps_unregister_source(ptp->pps_source);
313 
314 		if (ptp->kworker)
315 			kthread_destroy_worker(ptp->kworker);
316 
317 		put_device(&ptp->dev);
318 
319 		pr_err("failed to create posix clock\n");
320 		return ERR_PTR(err);
321 	}
322 
323 	return ptp;
324 
325 no_pps:
326 	ptp_cleanup_pin_groups(ptp);
327 no_pin_groups:
328 	kfree(ptp->vclock_index);
329 no_mem_for_vclocks:
330 	if (ptp->kworker)
331 		kthread_destroy_worker(ptp->kworker);
332 kworker_err:
333 	mutex_destroy(&ptp->tsevq_mux);
334 	mutex_destroy(&ptp->pincfg_mux);
335 	mutex_destroy(&ptp->n_vclocks_mux);
336 	ida_free(&ptp_clocks_map, index);
337 no_slot:
338 	kfree(ptp);
339 no_memory:
340 	return ERR_PTR(err);
341 }
342 EXPORT_SYMBOL(ptp_clock_register);
343 
344 static int unregister_vclock(struct device *dev, void *data)
345 {
346 	struct ptp_clock *ptp = dev_get_drvdata(dev);
347 
348 	ptp_vclock_unregister(info_to_vclock(ptp->info));
349 	return 0;
350 }
351 
352 int ptp_clock_unregister(struct ptp_clock *ptp)
353 {
354 	if (ptp_vclock_in_use(ptp)) {
355 		device_for_each_child(&ptp->dev, NULL, unregister_vclock);
356 	}
357 
358 	ptp->defunct = 1;
359 	wake_up_interruptible(&ptp->tsev_wq);
360 
361 	if (ptp->kworker) {
362 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
363 		kthread_destroy_worker(ptp->kworker);
364 	}
365 
366 	/* Release the clock's resources. */
367 	if (ptp->pps_source)
368 		pps_unregister_source(ptp->pps_source);
369 
370 	posix_clock_unregister(&ptp->clock);
371 
372 	return 0;
373 }
374 EXPORT_SYMBOL(ptp_clock_unregister);
375 
376 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
377 {
378 	struct pps_event_time evt;
379 
380 	switch (event->type) {
381 
382 	case PTP_CLOCK_ALARM:
383 		break;
384 
385 	case PTP_CLOCK_EXTTS:
386 		enqueue_external_timestamp(&ptp->tsevq, event);
387 		wake_up_interruptible(&ptp->tsev_wq);
388 		break;
389 
390 	case PTP_CLOCK_PPS:
391 		pps_get_ts(&evt);
392 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
393 		break;
394 
395 	case PTP_CLOCK_PPSUSR:
396 		pps_event(ptp->pps_source, &event->pps_times,
397 			  PTP_PPS_EVENT, NULL);
398 		break;
399 	}
400 }
401 EXPORT_SYMBOL(ptp_clock_event);
402 
403 int ptp_clock_index(struct ptp_clock *ptp)
404 {
405 	return ptp->index;
406 }
407 EXPORT_SYMBOL(ptp_clock_index);
408 
409 int ptp_find_pin(struct ptp_clock *ptp,
410 		 enum ptp_pin_function func, unsigned int chan)
411 {
412 	struct ptp_pin_desc *pin = NULL;
413 	int i;
414 
415 	for (i = 0; i < ptp->info->n_pins; i++) {
416 		if (ptp->info->pin_config[i].func == func &&
417 		    ptp->info->pin_config[i].chan == chan) {
418 			pin = &ptp->info->pin_config[i];
419 			break;
420 		}
421 	}
422 
423 	return pin ? i : -1;
424 }
425 EXPORT_SYMBOL(ptp_find_pin);
426 
427 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
428 			  enum ptp_pin_function func, unsigned int chan)
429 {
430 	int result;
431 
432 	mutex_lock(&ptp->pincfg_mux);
433 
434 	result = ptp_find_pin(ptp, func, chan);
435 
436 	mutex_unlock(&ptp->pincfg_mux);
437 
438 	return result;
439 }
440 EXPORT_SYMBOL(ptp_find_pin_unlocked);
441 
442 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
443 {
444 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
445 }
446 EXPORT_SYMBOL(ptp_schedule_worker);
447 
448 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
449 {
450 	kthread_cancel_delayed_work_sync(&ptp->aux_work);
451 }
452 EXPORT_SYMBOL(ptp_cancel_worker_sync);
453 
454 /* module operations */
455 
456 static void __exit ptp_exit(void)
457 {
458 	class_destroy(ptp_class);
459 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
460 	ida_destroy(&ptp_clocks_map);
461 }
462 
463 static int __init ptp_init(void)
464 {
465 	int err;
466 
467 	ptp_class = class_create("ptp");
468 	if (IS_ERR(ptp_class)) {
469 		pr_err("ptp: failed to allocate class\n");
470 		return PTR_ERR(ptp_class);
471 	}
472 
473 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
474 	if (err < 0) {
475 		pr_err("ptp: failed to allocate device region\n");
476 		goto no_region;
477 	}
478 
479 	ptp_class->dev_groups = ptp_groups;
480 	pr_info("PTP clock support registered\n");
481 	return 0;
482 
483 no_region:
484 	class_destroy(ptp_class);
485 	return err;
486 }
487 
488 subsys_initcall(ptp_init);
489 module_exit(ptp_exit);
490 
491 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
492 MODULE_DESCRIPTION("PTP clocks support");
493 MODULE_LICENSE("GPL");
494