xref: /linux/drivers/ptp/ptp_clock.c (revision 7bb377107c72a40ab7505341f8626c8eb79a0cb7) 
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 			err = ops->adjphase(ops, tx->offset);
152 	} else if (tx->modes == 0) {
153 		tx->freq = ptp->dialed_frequency;
154 		err = 0;
155 	}
156 
157 	return err;
158 }
159 
160 static struct posix_clock_operations ptp_clock_ops = {
161 	.owner		= THIS_MODULE,
162 	.clock_adjtime	= ptp_clock_adjtime,
163 	.clock_gettime	= ptp_clock_gettime,
164 	.clock_getres	= ptp_clock_getres,
165 	.clock_settime	= ptp_clock_settime,
166 	.ioctl		= ptp_ioctl,
167 	.open		= ptp_open,
168 	.poll		= ptp_poll,
169 	.read		= ptp_read,
170 };
171 
172 static void ptp_clock_release(struct device *dev)
173 {
174 	struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
175 
176 	ptp_cleanup_pin_groups(ptp);
177 	mutex_destroy(&ptp->tsevq_mux);
178 	mutex_destroy(&ptp->pincfg_mux);
179 	ida_simple_remove(&ptp_clocks_map, ptp->index);
180 	kfree(ptp);
181 }
182 
183 static void ptp_aux_kworker(struct kthread_work *work)
184 {
185 	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
186 					     aux_work.work);
187 	struct ptp_clock_info *info = ptp->info;
188 	long delay;
189 
190 	delay = info->do_aux_work(info);
191 
192 	if (delay >= 0)
193 		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
194 }
195 
196 /* public interface */
197 
198 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
199 				     struct device *parent)
200 {
201 	struct ptp_clock *ptp;
202 	int err = 0, index, major = MAJOR(ptp_devt);
203 
204 	if (info->n_alarm > PTP_MAX_ALARMS)
205 		return ERR_PTR(-EINVAL);
206 
207 	/* Initialize a clock structure. */
208 	err = -ENOMEM;
209 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
210 	if (ptp == NULL)
211 		goto no_memory;
212 
213 	index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
214 	if (index < 0) {
215 		err = index;
216 		goto no_slot;
217 	}
218 
219 	ptp->clock.ops = ptp_clock_ops;
220 	ptp->info = info;
221 	ptp->devid = MKDEV(major, index);
222 	ptp->index = index;
223 	spin_lock_init(&ptp->tsevq.lock);
224 	mutex_init(&ptp->tsevq_mux);
225 	mutex_init(&ptp->pincfg_mux);
226 	init_waitqueue_head(&ptp->tsev_wq);
227 
228 	if (ptp->info->do_aux_work) {
229 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
230 		ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
231 		if (IS_ERR(ptp->kworker)) {
232 			err = PTR_ERR(ptp->kworker);
233 			pr_err("failed to create ptp aux_worker %d\n", err);
234 			goto kworker_err;
235 		}
236 	}
237 
238 	err = ptp_populate_pin_groups(ptp);
239 	if (err)
240 		goto no_pin_groups;
241 
242 	/* Register a new PPS source. */
243 	if (info->pps) {
244 		struct pps_source_info pps;
245 		memset(&pps, 0, sizeof(pps));
246 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
247 		pps.mode = PTP_PPS_MODE;
248 		pps.owner = info->owner;
249 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
250 		if (IS_ERR(ptp->pps_source)) {
251 			err = PTR_ERR(ptp->pps_source);
252 			pr_err("failed to register pps source\n");
253 			goto no_pps;
254 		}
255 	}
256 
257 	/* Initialize a new device of our class in our clock structure. */
258 	device_initialize(&ptp->dev);
259 	ptp->dev.devt = ptp->devid;
260 	ptp->dev.class = ptp_class;
261 	ptp->dev.parent = parent;
262 	ptp->dev.groups = ptp->pin_attr_groups;
263 	ptp->dev.release = ptp_clock_release;
264 	dev_set_drvdata(&ptp->dev, ptp);
265 	dev_set_name(&ptp->dev, "ptp%d", ptp->index);
266 
267 	/* Create a posix clock and link it to the device. */
268 	err = posix_clock_register(&ptp->clock, &ptp->dev);
269 	if (err) {
270 		pr_err("failed to create posix clock\n");
271 		goto no_clock;
272 	}
273 
274 	return ptp;
275 
276 no_clock:
277 	if (ptp->pps_source)
278 		pps_unregister_source(ptp->pps_source);
279 no_pps:
280 	ptp_cleanup_pin_groups(ptp);
281 no_pin_groups:
282 	if (ptp->kworker)
283 		kthread_destroy_worker(ptp->kworker);
284 kworker_err:
285 	mutex_destroy(&ptp->tsevq_mux);
286 	mutex_destroy(&ptp->pincfg_mux);
287 	ida_simple_remove(&ptp_clocks_map, index);
288 no_slot:
289 	kfree(ptp);
290 no_memory:
291 	return ERR_PTR(err);
292 }
293 EXPORT_SYMBOL(ptp_clock_register);
294 
295 int ptp_clock_unregister(struct ptp_clock *ptp)
296 {
297 	ptp->defunct = 1;
298 	wake_up_interruptible(&ptp->tsev_wq);
299 
300 	if (ptp->kworker) {
301 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
302 		kthread_destroy_worker(ptp->kworker);
303 	}
304 
305 	/* Release the clock's resources. */
306 	if (ptp->pps_source)
307 		pps_unregister_source(ptp->pps_source);
308 
309 	posix_clock_unregister(&ptp->clock);
310 
311 	return 0;
312 }
313 EXPORT_SYMBOL(ptp_clock_unregister);
314 
315 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
316 {
317 	struct pps_event_time evt;
318 
319 	switch (event->type) {
320 
321 	case PTP_CLOCK_ALARM:
322 		break;
323 
324 	case PTP_CLOCK_EXTTS:
325 		enqueue_external_timestamp(&ptp->tsevq, event);
326 		wake_up_interruptible(&ptp->tsev_wq);
327 		break;
328 
329 	case PTP_CLOCK_PPS:
330 		pps_get_ts(&evt);
331 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
332 		break;
333 
334 	case PTP_CLOCK_PPSUSR:
335 		pps_event(ptp->pps_source, &event->pps_times,
336 			  PTP_PPS_EVENT, NULL);
337 		break;
338 	}
339 }
340 EXPORT_SYMBOL(ptp_clock_event);
341 
342 int ptp_clock_index(struct ptp_clock *ptp)
343 {
344 	return ptp->index;
345 }
346 EXPORT_SYMBOL(ptp_clock_index);
347 
348 int ptp_find_pin(struct ptp_clock *ptp,
349 		 enum ptp_pin_function func, unsigned int chan)
350 {
351 	struct ptp_pin_desc *pin = NULL;
352 	int i;
353 
354 	for (i = 0; i < ptp->info->n_pins; i++) {
355 		if (ptp->info->pin_config[i].func == func &&
356 		    ptp->info->pin_config[i].chan == chan) {
357 			pin = &ptp->info->pin_config[i];
358 			break;
359 		}
360 	}
361 
362 	return pin ? i : -1;
363 }
364 EXPORT_SYMBOL(ptp_find_pin);
365 
366 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
367 			  enum ptp_pin_function func, unsigned int chan)
368 {
369 	int result;
370 
371 	mutex_lock(&ptp->pincfg_mux);
372 
373 	result = ptp_find_pin(ptp, func, chan);
374 
375 	mutex_unlock(&ptp->pincfg_mux);
376 
377 	return result;
378 }
379 EXPORT_SYMBOL(ptp_find_pin_unlocked);
380 
381 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
382 {
383 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
384 }
385 EXPORT_SYMBOL(ptp_schedule_worker);
386 
387 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
388 {
389 	kthread_cancel_delayed_work_sync(&ptp->aux_work);
390 }
391 EXPORT_SYMBOL(ptp_cancel_worker_sync);
392 
393 /* module operations */
394 
395 static void __exit ptp_exit(void)
396 {
397 	class_destroy(ptp_class);
398 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
399 	ida_destroy(&ptp_clocks_map);
400 }
401 
402 static int __init ptp_init(void)
403 {
404 	int err;
405 
406 	ptp_class = class_create(THIS_MODULE, "ptp");
407 	if (IS_ERR(ptp_class)) {
408 		pr_err("ptp: failed to allocate class\n");
409 		return PTR_ERR(ptp_class);
410 	}
411 
412 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
413 	if (err < 0) {
414 		pr_err("ptp: failed to allocate device region\n");
415 		goto no_region;
416 	}
417 
418 	ptp_class->dev_groups = ptp_groups;
419 	pr_info("PTP clock support registered\n");
420 	return 0;
421 
422 no_region:
423 	class_destroy(ptp_class);
424 	return err;
425 }
426 
427 subsys_initcall(ptp_init);
428 module_exit(ptp_exit);
429 
430 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
431 MODULE_DESCRIPTION("PTP clocks support");
432 MODULE_LICENSE("GPL");
433