xref: /linux/drivers/ptp/ptp_clock.c (revision cc8c418b4fc09ed58ddd27b8e90ec797e9ca1e67) 
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 		if (ops->adjfine)
135 			err = ops->adjfine(ops, tx->freq);
136 		else
137 			err = ops->adjfreq(ops, ppb);
138 		ptp->dialed_frequency = tx->freq;
139 	} else if (tx->modes & ADJ_OFFSET) {
140 		if (ops->adjphase) {
141 			s32 offset = tx->offset;
142 
143 			if (!(tx->modes & ADJ_NANO))
144 				offset *= NSEC_PER_USEC;
145 
146 			err = ops->adjphase(ops, offset);
147 		}
148 	} else if (tx->modes == 0) {
149 		tx->freq = ptp->dialed_frequency;
150 		err = 0;
151 	}
152 
153 	return err;
154 }
155 
156 static struct posix_clock_operations ptp_clock_ops = {
157 	.owner		= THIS_MODULE,
158 	.clock_adjtime	= ptp_clock_adjtime,
159 	.clock_gettime	= ptp_clock_gettime,
160 	.clock_getres	= ptp_clock_getres,
161 	.clock_settime	= ptp_clock_settime,
162 	.ioctl		= ptp_ioctl,
163 	.open		= ptp_open,
164 	.poll		= ptp_poll,
165 	.read		= ptp_read,
166 };
167 
168 static void ptp_clock_release(struct device *dev)
169 {
170 	struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
171 
172 	ptp_cleanup_pin_groups(ptp);
173 	kfree(ptp->vclock_index);
174 	mutex_destroy(&ptp->tsevq_mux);
175 	mutex_destroy(&ptp->pincfg_mux);
176 	mutex_destroy(&ptp->n_vclocks_mux);
177 	ida_free(&ptp_clocks_map, ptp->index);
178 	kfree(ptp);
179 }
180 
181 static int ptp_getcycles64(struct ptp_clock_info *info, struct timespec64 *ts)
182 {
183 	if (info->getcyclesx64)
184 		return info->getcyclesx64(info, ts, NULL);
185 	else
186 		return info->gettime64(info, ts);
187 }
188 
189 static void ptp_aux_kworker(struct kthread_work *work)
190 {
191 	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
192 					     aux_work.work);
193 	struct ptp_clock_info *info = ptp->info;
194 	long delay;
195 
196 	delay = info->do_aux_work(info);
197 
198 	if (delay >= 0)
199 		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
200 }
201 
202 /* public interface */
203 
204 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
205 				     struct device *parent)
206 {
207 	struct ptp_clock *ptp;
208 	int err = 0, index, major = MAJOR(ptp_devt);
209 	size_t size;
210 
211 	if (info->n_alarm > PTP_MAX_ALARMS)
212 		return ERR_PTR(-EINVAL);
213 
214 	/* Initialize a clock structure. */
215 	err = -ENOMEM;
216 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
217 	if (ptp == NULL)
218 		goto no_memory;
219 
220 	index = ida_alloc_max(&ptp_clocks_map, MINORMASK, GFP_KERNEL);
221 	if (index < 0) {
222 		err = index;
223 		goto no_slot;
224 	}
225 
226 	ptp->clock.ops = ptp_clock_ops;
227 	ptp->info = info;
228 	ptp->devid = MKDEV(major, index);
229 	ptp->index = index;
230 	spin_lock_init(&ptp->tsevq.lock);
231 	mutex_init(&ptp->tsevq_mux);
232 	mutex_init(&ptp->pincfg_mux);
233 	mutex_init(&ptp->n_vclocks_mux);
234 	init_waitqueue_head(&ptp->tsev_wq);
235 
236 	if (ptp->info->getcycles64 || ptp->info->getcyclesx64) {
237 		ptp->has_cycles = true;
238 		if (!ptp->info->getcycles64 && ptp->info->getcyclesx64)
239 			ptp->info->getcycles64 = ptp_getcycles64;
240 	} else {
241 		/* Free running cycle counter not supported, use time. */
242 		ptp->info->getcycles64 = ptp_getcycles64;
243 
244 		if (ptp->info->gettimex64)
245 			ptp->info->getcyclesx64 = ptp->info->gettimex64;
246 
247 		if (ptp->info->getcrosststamp)
248 			ptp->info->getcrosscycles = ptp->info->getcrosststamp;
249 	}
250 
251 	if (ptp->info->do_aux_work) {
252 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
253 		ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
254 		if (IS_ERR(ptp->kworker)) {
255 			err = PTR_ERR(ptp->kworker);
256 			pr_err("failed to create ptp aux_worker %d\n", err);
257 			goto kworker_err;
258 		}
259 	}
260 
261 	/* PTP virtual clock is being registered under physical clock */
262 	if (parent && parent->class && parent->class->name &&
263 	    strcmp(parent->class->name, "ptp") == 0)
264 		ptp->is_virtual_clock = true;
265 
266 	if (!ptp->is_virtual_clock) {
267 		ptp->max_vclocks = PTP_DEFAULT_MAX_VCLOCKS;
268 
269 		size = sizeof(int) * ptp->max_vclocks;
270 		ptp->vclock_index = kzalloc(size, GFP_KERNEL);
271 		if (!ptp->vclock_index) {
272 			err = -ENOMEM;
273 			goto no_mem_for_vclocks;
274 		}
275 	}
276 
277 	err = ptp_populate_pin_groups(ptp);
278 	if (err)
279 		goto no_pin_groups;
280 
281 	/* Register a new PPS source. */
282 	if (info->pps) {
283 		struct pps_source_info pps;
284 		memset(&pps, 0, sizeof(pps));
285 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
286 		pps.mode = PTP_PPS_MODE;
287 		pps.owner = info->owner;
288 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
289 		if (IS_ERR(ptp->pps_source)) {
290 			err = PTR_ERR(ptp->pps_source);
291 			pr_err("failed to register pps source\n");
292 			goto no_pps;
293 		}
294 		ptp->pps_source->lookup_cookie = ptp;
295 	}
296 
297 	/* Initialize a new device of our class in our clock structure. */
298 	device_initialize(&ptp->dev);
299 	ptp->dev.devt = ptp->devid;
300 	ptp->dev.class = ptp_class;
301 	ptp->dev.parent = parent;
302 	ptp->dev.groups = ptp->pin_attr_groups;
303 	ptp->dev.release = ptp_clock_release;
304 	dev_set_drvdata(&ptp->dev, ptp);
305 	dev_set_name(&ptp->dev, "ptp%d", ptp->index);
306 
307 	/* Create a posix clock and link it to the device. */
308 	err = posix_clock_register(&ptp->clock, &ptp->dev);
309 	if (err) {
310 		if (ptp->pps_source)
311 			pps_unregister_source(ptp->pps_source);
312 
313 		if (ptp->kworker)
314 			kthread_destroy_worker(ptp->kworker);
315 
316 		put_device(&ptp->dev);
317 
318 		pr_err("failed to create posix clock\n");
319 		return ERR_PTR(err);
320 	}
321 
322 	return ptp;
323 
324 no_pps:
325 	ptp_cleanup_pin_groups(ptp);
326 no_pin_groups:
327 	kfree(ptp->vclock_index);
328 no_mem_for_vclocks:
329 	if (ptp->kworker)
330 		kthread_destroy_worker(ptp->kworker);
331 kworker_err:
332 	mutex_destroy(&ptp->tsevq_mux);
333 	mutex_destroy(&ptp->pincfg_mux);
334 	mutex_destroy(&ptp->n_vclocks_mux);
335 	ida_free(&ptp_clocks_map, index);
336 no_slot:
337 	kfree(ptp);
338 no_memory:
339 	return ERR_PTR(err);
340 }
341 EXPORT_SYMBOL(ptp_clock_register);
342 
343 static int unregister_vclock(struct device *dev, void *data)
344 {
345 	struct ptp_clock *ptp = dev_get_drvdata(dev);
346 
347 	ptp_vclock_unregister(info_to_vclock(ptp->info));
348 	return 0;
349 }
350 
351 int ptp_clock_unregister(struct ptp_clock *ptp)
352 {
353 	if (ptp_vclock_in_use(ptp)) {
354 		device_for_each_child(&ptp->dev, NULL, unregister_vclock);
355 	}
356 
357 	ptp->defunct = 1;
358 	wake_up_interruptible(&ptp->tsev_wq);
359 
360 	if (ptp->kworker) {
361 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
362 		kthread_destroy_worker(ptp->kworker);
363 	}
364 
365 	/* Release the clock's resources. */
366 	if (ptp->pps_source)
367 		pps_unregister_source(ptp->pps_source);
368 
369 	posix_clock_unregister(&ptp->clock);
370 
371 	return 0;
372 }
373 EXPORT_SYMBOL(ptp_clock_unregister);
374 
375 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
376 {
377 	struct pps_event_time evt;
378 
379 	switch (event->type) {
380 
381 	case PTP_CLOCK_ALARM:
382 		break;
383 
384 	case PTP_CLOCK_EXTTS:
385 		enqueue_external_timestamp(&ptp->tsevq, event);
386 		wake_up_interruptible(&ptp->tsev_wq);
387 		break;
388 
389 	case PTP_CLOCK_PPS:
390 		pps_get_ts(&evt);
391 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
392 		break;
393 
394 	case PTP_CLOCK_PPSUSR:
395 		pps_event(ptp->pps_source, &event->pps_times,
396 			  PTP_PPS_EVENT, NULL);
397 		break;
398 	}
399 }
400 EXPORT_SYMBOL(ptp_clock_event);
401 
402 int ptp_clock_index(struct ptp_clock *ptp)
403 {
404 	return ptp->index;
405 }
406 EXPORT_SYMBOL(ptp_clock_index);
407 
408 int ptp_find_pin(struct ptp_clock *ptp,
409 		 enum ptp_pin_function func, unsigned int chan)
410 {
411 	struct ptp_pin_desc *pin = NULL;
412 	int i;
413 
414 	for (i = 0; i < ptp->info->n_pins; i++) {
415 		if (ptp->info->pin_config[i].func == func &&
416 		    ptp->info->pin_config[i].chan == chan) {
417 			pin = &ptp->info->pin_config[i];
418 			break;
419 		}
420 	}
421 
422 	return pin ? i : -1;
423 }
424 EXPORT_SYMBOL(ptp_find_pin);
425 
426 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
427 			  enum ptp_pin_function func, unsigned int chan)
428 {
429 	int result;
430 
431 	mutex_lock(&ptp->pincfg_mux);
432 
433 	result = ptp_find_pin(ptp, func, chan);
434 
435 	mutex_unlock(&ptp->pincfg_mux);
436 
437 	return result;
438 }
439 EXPORT_SYMBOL(ptp_find_pin_unlocked);
440 
441 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
442 {
443 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
444 }
445 EXPORT_SYMBOL(ptp_schedule_worker);
446 
447 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
448 {
449 	kthread_cancel_delayed_work_sync(&ptp->aux_work);
450 }
451 EXPORT_SYMBOL(ptp_cancel_worker_sync);
452 
453 /* module operations */
454 
455 static void __exit ptp_exit(void)
456 {
457 	class_destroy(ptp_class);
458 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
459 	ida_destroy(&ptp_clocks_map);
460 }
461 
462 static int __init ptp_init(void)
463 {
464 	int err;
465 
466 	ptp_class = class_create(THIS_MODULE, "ptp");
467 	if (IS_ERR(ptp_class)) {
468 		pr_err("ptp: failed to allocate class\n");
469 		return PTR_ERR(ptp_class);
470 	}
471 
472 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
473 	if (err < 0) {
474 		pr_err("ptp: failed to allocate device region\n");
475 		goto no_region;
476 	}
477 
478 	ptp_class->dev_groups = ptp_groups;
479 	pr_info("PTP clock support registered\n");
480 	return 0;
481 
482 no_region:
483 	class_destroy(ptp_class);
484 	return err;
485 }
486 
487 subsys_initcall(ptp_init);
488 module_exit(ptp_exit);
489 
490 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
491 MODULE_DESCRIPTION("PTP clocks support");
492 MODULE_LICENSE("GPL");
493