xref: /openbmc/linux/drivers/ptp/ptp_clock.c (revision e5242c5f) 
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 	/* 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 
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 		if (!err)
137 			ptp->dialed_frequency = tx->freq;
138 	} else if (tx->modes & ADJ_OFFSET) {
139 		if (ops->adjphase) {
140 			s32 max_phase_adj = ops->getmaxphase(ops);
141 			s32 offset = tx->offset;
142 
143 			if (!(tx->modes & ADJ_NANO))
144 				offset *= NSEC_PER_USEC;
145 
146 			if (offset > max_phase_adj || offset < -max_phase_adj)
147 				return -ERANGE;
148 
149 			err = ops->adjphase(ops, offset);
150 		}
151 	} else if (tx->modes == 0) {
152 		tx->freq = ptp->dialed_frequency;
153 		err = 0;
154 	}
155 
156 	return err;
157 }
158 
159 static struct posix_clock_operations ptp_clock_ops = {
160 	.owner		= THIS_MODULE,
161 	.clock_adjtime	= ptp_clock_adjtime,
162 	.clock_gettime	= ptp_clock_gettime,
163 	.clock_getres	= ptp_clock_getres,
164 	.clock_settime	= ptp_clock_settime,
165 	.ioctl		= ptp_ioctl,
166 	.open		= ptp_open,
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 
175 	ptp_cleanup_pin_groups(ptp);
176 	kfree(ptp->vclock_index);
177 	mutex_destroy(&ptp->tsevq_mux);
178 	mutex_destroy(&ptp->pincfg_mux);
179 	mutex_destroy(&ptp->n_vclocks_mux);
180 	ida_free(&ptp_clocks_map, ptp->index);
181 	kfree(ptp);
182 }
183 
184 static int ptp_getcycles64(struct ptp_clock_info *info, struct timespec64 *ts)
185 {
186 	if (info->getcyclesx64)
187 		return info->getcyclesx64(info, ts, NULL);
188 	else
189 		return info->gettime64(info, ts);
190 }
191 
192 static void ptp_aux_kworker(struct kthread_work *work)
193 {
194 	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
195 					     aux_work.work);
196 	struct ptp_clock_info *info = ptp->info;
197 	long delay;
198 
199 	delay = info->do_aux_work(info);
200 
201 	if (delay >= 0)
202 		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
203 }
204 
205 /* public interface */
206 
207 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
208 				     struct device *parent)
209 {
210 	struct ptp_clock *ptp;
211 	int err = 0, index, major = MAJOR(ptp_devt);
212 	size_t size;
213 
214 	if (info->n_alarm > PTP_MAX_ALARMS)
215 		return ERR_PTR(-EINVAL);
216 
217 	/* Initialize a clock structure. */
218 	err = -ENOMEM;
219 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
220 	if (ptp == NULL)
221 		goto no_memory;
222 
223 	index = ida_alloc_max(&ptp_clocks_map, MINORMASK, GFP_KERNEL);
224 	if (index < 0) {
225 		err = index;
226 		goto no_slot;
227 	}
228 
229 	ptp->clock.ops = ptp_clock_ops;
230 	ptp->info = info;
231 	ptp->devid = MKDEV(major, index);
232 	ptp->index = index;
233 	spin_lock_init(&ptp->tsevq.lock);
234 	mutex_init(&ptp->tsevq_mux);
235 	mutex_init(&ptp->pincfg_mux);
236 	mutex_init(&ptp->n_vclocks_mux);
237 	init_waitqueue_head(&ptp->tsev_wq);
238 
239 	if (ptp->info->getcycles64 || ptp->info->getcyclesx64) {
240 		ptp->has_cycles = true;
241 		if (!ptp->info->getcycles64 && ptp->info->getcyclesx64)
242 			ptp->info->getcycles64 = ptp_getcycles64;
243 	} else {
244 		/* Free running cycle counter not supported, use time. */
245 		ptp->info->getcycles64 = ptp_getcycles64;
246 
247 		if (ptp->info->gettimex64)
248 			ptp->info->getcyclesx64 = ptp->info->gettimex64;
249 
250 		if (ptp->info->getcrosststamp)
251 			ptp->info->getcrosscycles = ptp->info->getcrosststamp;
252 	}
253 
254 	if (ptp->info->do_aux_work) {
255 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
256 		ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
257 		if (IS_ERR(ptp->kworker)) {
258 			err = PTR_ERR(ptp->kworker);
259 			pr_err("failed to create ptp aux_worker %d\n", err);
260 			goto kworker_err;
261 		}
262 	}
263 
264 	/* PTP virtual clock is being registered under physical clock */
265 	if (parent && parent->class && parent->class->name &&
266 	    strcmp(parent->class->name, "ptp") == 0)
267 		ptp->is_virtual_clock = true;
268 
269 	if (!ptp->is_virtual_clock) {
270 		ptp->max_vclocks = PTP_DEFAULT_MAX_VCLOCKS;
271 
272 		size = sizeof(int) * ptp->max_vclocks;
273 		ptp->vclock_index = kzalloc(size, GFP_KERNEL);
274 		if (!ptp->vclock_index) {
275 			err = -ENOMEM;
276 			goto no_mem_for_vclocks;
277 		}
278 	}
279 
280 	err = ptp_populate_pin_groups(ptp);
281 	if (err)
282 		goto no_pin_groups;
283 
284 	/* Register a new PPS source. */
285 	if (info->pps) {
286 		struct pps_source_info pps;
287 		memset(&pps, 0, sizeof(pps));
288 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
289 		pps.mode = PTP_PPS_MODE;
290 		pps.owner = info->owner;
291 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
292 		if (IS_ERR(ptp->pps_source)) {
293 			err = PTR_ERR(ptp->pps_source);
294 			pr_err("failed to register pps source\n");
295 			goto no_pps;
296 		}
297 		ptp->pps_source->lookup_cookie = ptp;
298 	}
299 
300 	/* Initialize a new device of our class in our clock structure. */
301 	device_initialize(&ptp->dev);
302 	ptp->dev.devt = ptp->devid;
303 	ptp->dev.class = ptp_class;
304 	ptp->dev.parent = parent;
305 	ptp->dev.groups = ptp->pin_attr_groups;
306 	ptp->dev.release = ptp_clock_release;
307 	dev_set_drvdata(&ptp->dev, ptp);
308 	dev_set_name(&ptp->dev, "ptp%d", ptp->index);
309 
310 	/* Create a posix clock and link it to the device. */
311 	err = posix_clock_register(&ptp->clock, &ptp->dev);
312 	if (err) {
313 		if (ptp->pps_source)
314 			pps_unregister_source(ptp->pps_source);
315 
316 		if (ptp->kworker)
317 			kthread_destroy_worker(ptp->kworker);
318 
319 		put_device(&ptp->dev);
320 
321 		pr_err("failed to create posix clock\n");
322 		return ERR_PTR(err);
323 	}
324 
325 	return ptp;
326 
327 no_pps:
328 	ptp_cleanup_pin_groups(ptp);
329 no_pin_groups:
330 	kfree(ptp->vclock_index);
331 no_mem_for_vclocks:
332 	if (ptp->kworker)
333 		kthread_destroy_worker(ptp->kworker);
334 kworker_err:
335 	mutex_destroy(&ptp->tsevq_mux);
336 	mutex_destroy(&ptp->pincfg_mux);
337 	mutex_destroy(&ptp->n_vclocks_mux);
338 	ida_free(&ptp_clocks_map, index);
339 no_slot:
340 	kfree(ptp);
341 no_memory:
342 	return ERR_PTR(err);
343 }
344 EXPORT_SYMBOL(ptp_clock_register);
345 
346 static int unregister_vclock(struct device *dev, void *data)
347 {
348 	struct ptp_clock *ptp = dev_get_drvdata(dev);
349 
350 	ptp_vclock_unregister(info_to_vclock(ptp->info));
351 	return 0;
352 }
353 
354 int ptp_clock_unregister(struct ptp_clock *ptp)
355 {
356 	if (ptp_vclock_in_use(ptp)) {
357 		device_for_each_child(&ptp->dev, NULL, unregister_vclock);
358 	}
359 
360 	ptp->defunct = 1;
361 	wake_up_interruptible(&ptp->tsev_wq);
362 
363 	if (ptp->kworker) {
364 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
365 		kthread_destroy_worker(ptp->kworker);
366 	}
367 
368 	/* Release the clock's resources. */
369 	if (ptp->pps_source)
370 		pps_unregister_source(ptp->pps_source);
371 
372 	posix_clock_unregister(&ptp->clock);
373 
374 	return 0;
375 }
376 EXPORT_SYMBOL(ptp_clock_unregister);
377 
378 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
379 {
380 	struct pps_event_time evt;
381 
382 	switch (event->type) {
383 
384 	case PTP_CLOCK_ALARM:
385 		break;
386 
387 	case PTP_CLOCK_EXTTS:
388 		enqueue_external_timestamp(&ptp->tsevq, event);
389 		wake_up_interruptible(&ptp->tsev_wq);
390 		break;
391 
392 	case PTP_CLOCK_PPS:
393 		pps_get_ts(&evt);
394 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
395 		break;
396 
397 	case PTP_CLOCK_PPSUSR:
398 		pps_event(ptp->pps_source, &event->pps_times,
399 			  PTP_PPS_EVENT, NULL);
400 		break;
401 	}
402 }
403 EXPORT_SYMBOL(ptp_clock_event);
404 
405 int ptp_clock_index(struct ptp_clock *ptp)
406 {
407 	return ptp->index;
408 }
409 EXPORT_SYMBOL(ptp_clock_index);
410 
411 int ptp_find_pin(struct ptp_clock *ptp,
412 		 enum ptp_pin_function func, unsigned int chan)
413 {
414 	struct ptp_pin_desc *pin = NULL;
415 	int i;
416 
417 	for (i = 0; i < ptp->info->n_pins; i++) {
418 		if (ptp->info->pin_config[i].func == func &&
419 		    ptp->info->pin_config[i].chan == chan) {
420 			pin = &ptp->info->pin_config[i];
421 			break;
422 		}
423 	}
424 
425 	return pin ? i : -1;
426 }
427 EXPORT_SYMBOL(ptp_find_pin);
428 
429 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
430 			  enum ptp_pin_function func, unsigned int chan)
431 {
432 	int result;
433 
434 	mutex_lock(&ptp->pincfg_mux);
435 
436 	result = ptp_find_pin(ptp, func, chan);
437 
438 	mutex_unlock(&ptp->pincfg_mux);
439 
440 	return result;
441 }
442 EXPORT_SYMBOL(ptp_find_pin_unlocked);
443 
444 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
445 {
446 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
447 }
448 EXPORT_SYMBOL(ptp_schedule_worker);
449 
450 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
451 {
452 	kthread_cancel_delayed_work_sync(&ptp->aux_work);
453 }
454 EXPORT_SYMBOL(ptp_cancel_worker_sync);
455 
456 /* module operations */
457 
458 static void __exit ptp_exit(void)
459 {
460 	class_destroy(ptp_class);
461 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
462 	ida_destroy(&ptp_clocks_map);
463 }
464 
465 static int __init ptp_init(void)
466 {
467 	int err;
468 
469 	ptp_class = class_create("ptp");
470 	if (IS_ERR(ptp_class)) {
471 		pr_err("ptp: failed to allocate class\n");
472 		return PTR_ERR(ptp_class);
473 	}
474 
475 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
476 	if (err < 0) {
477 		pr_err("ptp: failed to allocate device region\n");
478 		goto no_region;
479 	}
480 
481 	ptp_class->dev_groups = ptp_groups;
482 	pr_info("PTP clock support registered\n");
483 	return 0;
484 
485 no_region:
486 	class_destroy(ptp_class);
487 	return err;
488 }
489 
490 subsys_initcall(ptp_init);
491 module_exit(ptp_exit);
492 
493 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
494 MODULE_DESCRIPTION("PTP clocks support");
495 MODULE_LICENSE("GPL");
496