xref: /linux/drivers/ptp/ptp_clock.c (revision 3839a7460721b87501134697b7b90c45dcc7825d) 
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 /* private globals */
28 
29 static dev_t ptp_devt;
30 static struct class *ptp_class;
31 
32 static DEFINE_IDA(ptp_clocks_map);
33 
34 /* time stamp event queue operations */
35 
36 static inline int queue_free(struct timestamp_event_queue *q)
37 {
38 	return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
39 }
40 
41 static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
42 				       struct ptp_clock_event *src)
43 {
44 	struct ptp_extts_event *dst;
45 	unsigned long flags;
46 	s64 seconds;
47 	u32 remainder;
48 
49 	seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
50 
51 	spin_lock_irqsave(&queue->lock, flags);
52 
53 	dst = &queue->buf[queue->tail];
54 	dst->index = src->index;
55 	dst->t.sec = seconds;
56 	dst->t.nsec = remainder;
57 
58 	if (!queue_free(queue))
59 		queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
60 
61 	queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;
62 
63 	spin_unlock_irqrestore(&queue->lock, flags);
64 }
65 
66 s32 scaled_ppm_to_ppb(long ppm)
67 {
68 	/*
69 	 * The 'freq' field in the 'struct timex' is in parts per
70 	 * million, but with a 16 bit binary fractional field.
71 	 *
72 	 * We want to calculate
73 	 *
74 	 *    ppb = scaled_ppm * 1000 / 2^16
75 	 *
76 	 * which simplifies to
77 	 *
78 	 *    ppb = scaled_ppm * 125 / 2^13
79 	 */
80 	s64 ppb = 1 + ppm;
81 	ppb *= 125;
82 	ppb >>= 13;
83 	return (s32) ppb;
84 }
85 EXPORT_SYMBOL(scaled_ppm_to_ppb);
86 
87 /* posix clock implementation */
88 
89 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
90 {
91 	tp->tv_sec = 0;
92 	tp->tv_nsec = 1;
93 	return 0;
94 }
95 
96 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
97 {
98 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
99 
100 	return  ptp->info->settime64(ptp->info, tp);
101 }
102 
103 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
104 {
105 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
106 	int err;
107 
108 	if (ptp->info->gettimex64)
109 		err = ptp->info->gettimex64(ptp->info, tp, NULL);
110 	else
111 		err = ptp->info->gettime64(ptp->info, tp);
112 	return err;
113 }
114 
115 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
116 {
117 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
118 	struct ptp_clock_info *ops;
119 	int err = -EOPNOTSUPP;
120 
121 	ops = ptp->info;
122 
123 	if (tx->modes & ADJ_SETOFFSET) {
124 		struct timespec64 ts;
125 		ktime_t kt;
126 		s64 delta;
127 
128 		ts.tv_sec  = tx->time.tv_sec;
129 		ts.tv_nsec = tx->time.tv_usec;
130 
131 		if (!(tx->modes & ADJ_NANO))
132 			ts.tv_nsec *= 1000;
133 
134 		if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
135 			return -EINVAL;
136 
137 		kt = timespec64_to_ktime(ts);
138 		delta = ktime_to_ns(kt);
139 		err = ops->adjtime(ops, delta);
140 	} else if (tx->modes & ADJ_FREQUENCY) {
141 		s32 ppb = scaled_ppm_to_ppb(tx->freq);
142 		if (ppb > ops->max_adj || ppb < -ops->max_adj)
143 			return -ERANGE;
144 		if (ops->adjfine)
145 			err = ops->adjfine(ops, tx->freq);
146 		else
147 			err = ops->adjfreq(ops, ppb);
148 		ptp->dialed_frequency = tx->freq;
149 	} else if (tx->modes & ADJ_OFFSET) {
150 		if (ops->adjphase) {
151 			s32 offset = tx->offset;
152 
153 			if (!(tx->modes & ADJ_NANO))
154 				offset *= NSEC_PER_USEC;
155 
156 			err = ops->adjphase(ops, offset);
157 		}
158 	} else if (tx->modes == 0) {
159 		tx->freq = ptp->dialed_frequency;
160 		err = 0;
161 	}
162 
163 	return err;
164 }
165 
166 static struct posix_clock_operations ptp_clock_ops = {
167 	.owner		= THIS_MODULE,
168 	.clock_adjtime	= ptp_clock_adjtime,
169 	.clock_gettime	= ptp_clock_gettime,
170 	.clock_getres	= ptp_clock_getres,
171 	.clock_settime	= ptp_clock_settime,
172 	.ioctl		= ptp_ioctl,
173 	.open		= ptp_open,
174 	.poll		= ptp_poll,
175 	.read		= ptp_read,
176 };
177 
178 static void ptp_clock_release(struct device *dev)
179 {
180 	struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
181 
182 	ptp_cleanup_pin_groups(ptp);
183 	mutex_destroy(&ptp->tsevq_mux);
184 	mutex_destroy(&ptp->pincfg_mux);
185 	ida_simple_remove(&ptp_clocks_map, ptp->index);
186 	kfree(ptp);
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 
210 	if (info->n_alarm > PTP_MAX_ALARMS)
211 		return ERR_PTR(-EINVAL);
212 
213 	/* Initialize a clock structure. */
214 	err = -ENOMEM;
215 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
216 	if (ptp == NULL)
217 		goto no_memory;
218 
219 	index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
220 	if (index < 0) {
221 		err = index;
222 		goto no_slot;
223 	}
224 
225 	ptp->clock.ops = ptp_clock_ops;
226 	ptp->info = info;
227 	ptp->devid = MKDEV(major, index);
228 	ptp->index = index;
229 	spin_lock_init(&ptp->tsevq.lock);
230 	mutex_init(&ptp->tsevq_mux);
231 	mutex_init(&ptp->pincfg_mux);
232 	init_waitqueue_head(&ptp->tsev_wq);
233 
234 	if (ptp->info->do_aux_work) {
235 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
236 		ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
237 		if (IS_ERR(ptp->kworker)) {
238 			err = PTR_ERR(ptp->kworker);
239 			pr_err("failed to create ptp aux_worker %d\n", err);
240 			goto kworker_err;
241 		}
242 	}
243 
244 	err = ptp_populate_pin_groups(ptp);
245 	if (err)
246 		goto no_pin_groups;
247 
248 	/* Register a new PPS source. */
249 	if (info->pps) {
250 		struct pps_source_info pps;
251 		memset(&pps, 0, sizeof(pps));
252 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
253 		pps.mode = PTP_PPS_MODE;
254 		pps.owner = info->owner;
255 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
256 		if (IS_ERR(ptp->pps_source)) {
257 			err = PTR_ERR(ptp->pps_source);
258 			pr_err("failed to register pps source\n");
259 			goto no_pps;
260 		}
261 	}
262 
263 	/* Initialize a new device of our class in our clock structure. */
264 	device_initialize(&ptp->dev);
265 	ptp->dev.devt = ptp->devid;
266 	ptp->dev.class = ptp_class;
267 	ptp->dev.parent = parent;
268 	ptp->dev.groups = ptp->pin_attr_groups;
269 	ptp->dev.release = ptp_clock_release;
270 	dev_set_drvdata(&ptp->dev, ptp);
271 	dev_set_name(&ptp->dev, "ptp%d", ptp->index);
272 
273 	/* Create a posix clock and link it to the device. */
274 	err = posix_clock_register(&ptp->clock, &ptp->dev);
275 	if (err) {
276 		pr_err("failed to create posix clock\n");
277 		goto no_clock;
278 	}
279 
280 	return ptp;
281 
282 no_clock:
283 	if (ptp->pps_source)
284 		pps_unregister_source(ptp->pps_source);
285 no_pps:
286 	ptp_cleanup_pin_groups(ptp);
287 no_pin_groups:
288 	if (ptp->kworker)
289 		kthread_destroy_worker(ptp->kworker);
290 kworker_err:
291 	mutex_destroy(&ptp->tsevq_mux);
292 	mutex_destroy(&ptp->pincfg_mux);
293 	ida_simple_remove(&ptp_clocks_map, index);
294 no_slot:
295 	kfree(ptp);
296 no_memory:
297 	return ERR_PTR(err);
298 }
299 EXPORT_SYMBOL(ptp_clock_register);
300 
301 int ptp_clock_unregister(struct ptp_clock *ptp)
302 {
303 	ptp->defunct = 1;
304 	wake_up_interruptible(&ptp->tsev_wq);
305 
306 	if (ptp->kworker) {
307 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
308 		kthread_destroy_worker(ptp->kworker);
309 	}
310 
311 	/* Release the clock's resources. */
312 	if (ptp->pps_source)
313 		pps_unregister_source(ptp->pps_source);
314 
315 	posix_clock_unregister(&ptp->clock);
316 
317 	return 0;
318 }
319 EXPORT_SYMBOL(ptp_clock_unregister);
320 
321 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
322 {
323 	struct pps_event_time evt;
324 
325 	switch (event->type) {
326 
327 	case PTP_CLOCK_ALARM:
328 		break;
329 
330 	case PTP_CLOCK_EXTTS:
331 		enqueue_external_timestamp(&ptp->tsevq, event);
332 		wake_up_interruptible(&ptp->tsev_wq);
333 		break;
334 
335 	case PTP_CLOCK_PPS:
336 		pps_get_ts(&evt);
337 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
338 		break;
339 
340 	case PTP_CLOCK_PPSUSR:
341 		pps_event(ptp->pps_source, &event->pps_times,
342 			  PTP_PPS_EVENT, NULL);
343 		break;
344 	}
345 }
346 EXPORT_SYMBOL(ptp_clock_event);
347 
348 int ptp_clock_index(struct ptp_clock *ptp)
349 {
350 	return ptp->index;
351 }
352 EXPORT_SYMBOL(ptp_clock_index);
353 
354 int ptp_find_pin(struct ptp_clock *ptp,
355 		 enum ptp_pin_function func, unsigned int chan)
356 {
357 	struct ptp_pin_desc *pin = NULL;
358 	int i;
359 
360 	for (i = 0; i < ptp->info->n_pins; i++) {
361 		if (ptp->info->pin_config[i].func == func &&
362 		    ptp->info->pin_config[i].chan == chan) {
363 			pin = &ptp->info->pin_config[i];
364 			break;
365 		}
366 	}
367 
368 	return pin ? i : -1;
369 }
370 EXPORT_SYMBOL(ptp_find_pin);
371 
372 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
373 			  enum ptp_pin_function func, unsigned int chan)
374 {
375 	int result;
376 
377 	mutex_lock(&ptp->pincfg_mux);
378 
379 	result = ptp_find_pin(ptp, func, chan);
380 
381 	mutex_unlock(&ptp->pincfg_mux);
382 
383 	return result;
384 }
385 EXPORT_SYMBOL(ptp_find_pin_unlocked);
386 
387 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
388 {
389 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
390 }
391 EXPORT_SYMBOL(ptp_schedule_worker);
392 
393 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
394 {
395 	kthread_cancel_delayed_work_sync(&ptp->aux_work);
396 }
397 EXPORT_SYMBOL(ptp_cancel_worker_sync);
398 
399 /* module operations */
400 
401 static void __exit ptp_exit(void)
402 {
403 	class_destroy(ptp_class);
404 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
405 	ida_destroy(&ptp_clocks_map);
406 }
407 
408 static int __init ptp_init(void)
409 {
410 	int err;
411 
412 	ptp_class = class_create(THIS_MODULE, "ptp");
413 	if (IS_ERR(ptp_class)) {
414 		pr_err("ptp: failed to allocate class\n");
415 		return PTR_ERR(ptp_class);
416 	}
417 
418 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
419 	if (err < 0) {
420 		pr_err("ptp: failed to allocate device region\n");
421 		goto no_region;
422 	}
423 
424 	ptp_class->dev_groups = ptp_groups;
425 	pr_info("PTP clock support registered\n");
426 	return 0;
427 
428 no_region:
429 	class_destroy(ptp_class);
430 	return err;
431 }
432 
433 subsys_initcall(ptp_init);
434 module_exit(ptp_exit);
435 
436 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
437 MODULE_DESCRIPTION("PTP clocks support");
438 MODULE_LICENSE("GPL");
439