xref: /linux/drivers/ptp/ptp_clock.c (revision 44f57d78) 
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 static 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 
86 /* posix clock implementation */
87 
88 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
89 {
90 	tp->tv_sec = 0;
91 	tp->tv_nsec = 1;
92 	return 0;
93 }
94 
95 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
96 {
97 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
98 
99 	return  ptp->info->settime64(ptp->info, tp);
100 }
101 
102 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
103 {
104 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
105 	int err;
106 
107 	if (ptp->info->gettimex64)
108 		err = ptp->info->gettimex64(ptp->info, tp, NULL);
109 	else
110 		err = ptp->info->gettime64(ptp->info, tp);
111 	return err;
112 }
113 
114 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
115 {
116 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
117 	struct ptp_clock_info *ops;
118 	int err = -EOPNOTSUPP;
119 
120 	ops = ptp->info;
121 
122 	if (tx->modes & ADJ_SETOFFSET) {
123 		struct timespec64 ts;
124 		ktime_t kt;
125 		s64 delta;
126 
127 		ts.tv_sec  = tx->time.tv_sec;
128 		ts.tv_nsec = tx->time.tv_usec;
129 
130 		if (!(tx->modes & ADJ_NANO))
131 			ts.tv_nsec *= 1000;
132 
133 		if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
134 			return -EINVAL;
135 
136 		kt = timespec64_to_ktime(ts);
137 		delta = ktime_to_ns(kt);
138 		err = ops->adjtime(ops, delta);
139 	} else if (tx->modes & ADJ_FREQUENCY) {
140 		s32 ppb = scaled_ppm_to_ppb(tx->freq);
141 		if (ppb > ops->max_adj || ppb < -ops->max_adj)
142 			return -ERANGE;
143 		if (ops->adjfine)
144 			err = ops->adjfine(ops, tx->freq);
145 		else
146 			err = ops->adjfreq(ops, ppb);
147 		ptp->dialed_frequency = tx->freq;
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 delete_ptp_clock(struct posix_clock *pc)
169 {
170 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
171 
172 	mutex_destroy(&ptp->tsevq_mux);
173 	mutex_destroy(&ptp->pincfg_mux);
174 	ida_simple_remove(&ptp_clocks_map, ptp->index);
175 	kfree(ptp);
176 }
177 
178 static void ptp_aux_kworker(struct kthread_work *work)
179 {
180 	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
181 					     aux_work.work);
182 	struct ptp_clock_info *info = ptp->info;
183 	long delay;
184 
185 	delay = info->do_aux_work(info);
186 
187 	if (delay >= 0)
188 		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
189 }
190 
191 /* public interface */
192 
193 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
194 				     struct device *parent)
195 {
196 	struct ptp_clock *ptp;
197 	int err = 0, index, major = MAJOR(ptp_devt);
198 
199 	if (info->n_alarm > PTP_MAX_ALARMS)
200 		return ERR_PTR(-EINVAL);
201 
202 	/* Initialize a clock structure. */
203 	err = -ENOMEM;
204 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
205 	if (ptp == NULL)
206 		goto no_memory;
207 
208 	index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
209 	if (index < 0) {
210 		err = index;
211 		goto no_slot;
212 	}
213 
214 	ptp->clock.ops = ptp_clock_ops;
215 	ptp->clock.release = delete_ptp_clock;
216 	ptp->info = info;
217 	ptp->devid = MKDEV(major, index);
218 	ptp->index = index;
219 	spin_lock_init(&ptp->tsevq.lock);
220 	mutex_init(&ptp->tsevq_mux);
221 	mutex_init(&ptp->pincfg_mux);
222 	init_waitqueue_head(&ptp->tsev_wq);
223 
224 	if (ptp->info->do_aux_work) {
225 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
226 		ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
227 		if (IS_ERR(ptp->kworker)) {
228 			err = PTR_ERR(ptp->kworker);
229 			pr_err("failed to create ptp aux_worker %d\n", err);
230 			goto kworker_err;
231 		}
232 	}
233 
234 	err = ptp_populate_pin_groups(ptp);
235 	if (err)
236 		goto no_pin_groups;
237 
238 	/* Create a new device in our class. */
239 	ptp->dev = device_create_with_groups(ptp_class, parent, ptp->devid,
240 					     ptp, ptp->pin_attr_groups,
241 					     "ptp%d", ptp->index);
242 	if (IS_ERR(ptp->dev)) {
243 		err = PTR_ERR(ptp->dev);
244 		goto no_device;
245 	}
246 
247 	/* Register a new PPS source. */
248 	if (info->pps) {
249 		struct pps_source_info pps;
250 		memset(&pps, 0, sizeof(pps));
251 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
252 		pps.mode = PTP_PPS_MODE;
253 		pps.owner = info->owner;
254 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
255 		if (IS_ERR(ptp->pps_source)) {
256 			err = PTR_ERR(ptp->pps_source);
257 			pr_err("failed to register pps source\n");
258 			goto no_pps;
259 		}
260 	}
261 
262 	/* Create a posix clock. */
263 	err = posix_clock_register(&ptp->clock, ptp->devid);
264 	if (err) {
265 		pr_err("failed to create posix clock\n");
266 		goto no_clock;
267 	}
268 
269 	return ptp;
270 
271 no_clock:
272 	if (ptp->pps_source)
273 		pps_unregister_source(ptp->pps_source);
274 no_pps:
275 	device_destroy(ptp_class, ptp->devid);
276 no_device:
277 	ptp_cleanup_pin_groups(ptp);
278 no_pin_groups:
279 	if (ptp->kworker)
280 		kthread_destroy_worker(ptp->kworker);
281 kworker_err:
282 	mutex_destroy(&ptp->tsevq_mux);
283 	mutex_destroy(&ptp->pincfg_mux);
284 	ida_simple_remove(&ptp_clocks_map, index);
285 no_slot:
286 	kfree(ptp);
287 no_memory:
288 	return ERR_PTR(err);
289 }
290 EXPORT_SYMBOL(ptp_clock_register);
291 
292 int ptp_clock_unregister(struct ptp_clock *ptp)
293 {
294 	ptp->defunct = 1;
295 	wake_up_interruptible(&ptp->tsev_wq);
296 
297 	if (ptp->kworker) {
298 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
299 		kthread_destroy_worker(ptp->kworker);
300 	}
301 
302 	/* Release the clock's resources. */
303 	if (ptp->pps_source)
304 		pps_unregister_source(ptp->pps_source);
305 
306 	device_destroy(ptp_class, ptp->devid);
307 	ptp_cleanup_pin_groups(ptp);
308 
309 	posix_clock_unregister(&ptp->clock);
310 	return 0;
311 }
312 EXPORT_SYMBOL(ptp_clock_unregister);
313 
314 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
315 {
316 	struct pps_event_time evt;
317 
318 	switch (event->type) {
319 
320 	case PTP_CLOCK_ALARM:
321 		break;
322 
323 	case PTP_CLOCK_EXTTS:
324 		enqueue_external_timestamp(&ptp->tsevq, event);
325 		wake_up_interruptible(&ptp->tsev_wq);
326 		break;
327 
328 	case PTP_CLOCK_PPS:
329 		pps_get_ts(&evt);
330 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
331 		break;
332 
333 	case PTP_CLOCK_PPSUSR:
334 		pps_event(ptp->pps_source, &event->pps_times,
335 			  PTP_PPS_EVENT, NULL);
336 		break;
337 	}
338 }
339 EXPORT_SYMBOL(ptp_clock_event);
340 
341 int ptp_clock_index(struct ptp_clock *ptp)
342 {
343 	return ptp->index;
344 }
345 EXPORT_SYMBOL(ptp_clock_index);
346 
347 int ptp_find_pin(struct ptp_clock *ptp,
348 		 enum ptp_pin_function func, unsigned int chan)
349 {
350 	struct ptp_pin_desc *pin = NULL;
351 	int i;
352 
353 	mutex_lock(&ptp->pincfg_mux);
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 	mutex_unlock(&ptp->pincfg_mux);
362 
363 	return pin ? i : -1;
364 }
365 EXPORT_SYMBOL(ptp_find_pin);
366 
367 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
368 {
369 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
370 }
371 EXPORT_SYMBOL(ptp_schedule_worker);
372 
373 /* module operations */
374 
375 static void __exit ptp_exit(void)
376 {
377 	class_destroy(ptp_class);
378 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
379 	ida_destroy(&ptp_clocks_map);
380 }
381 
382 static int __init ptp_init(void)
383 {
384 	int err;
385 
386 	ptp_class = class_create(THIS_MODULE, "ptp");
387 	if (IS_ERR(ptp_class)) {
388 		pr_err("ptp: failed to allocate class\n");
389 		return PTR_ERR(ptp_class);
390 	}
391 
392 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
393 	if (err < 0) {
394 		pr_err("ptp: failed to allocate device region\n");
395 		goto no_region;
396 	}
397 
398 	ptp_class->dev_groups = ptp_groups;
399 	pr_info("PTP clock support registered\n");
400 	return 0;
401 
402 no_region:
403 	class_destroy(ptp_class);
404 	return err;
405 }
406 
407 subsys_initcall(ptp_init);
408 module_exit(ptp_exit);
409 
410 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
411 MODULE_DESCRIPTION("PTP clocks support");
412 MODULE_LICENSE("GPL");
413