xref: /openbmc/linux/drivers/ptp/ptp_clock.c (revision 981ab3f1) 
1 /*
2  * PTP 1588 clock support
3  *
4  * Copyright (C) 2010 OMICRON electronics GmbH
5  *
6  *  This program is free software; you can redistribute it and/or modify
7  *  it under the terms of the GNU General Public License as published by
8  *  the Free Software Foundation; either version 2 of the License, or
9  *  (at your option) any later version.
10  *
11  *  This program is distributed in the hope that it will be useful,
12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *  GNU General Public License for more details.
15  *
16  *  You should have received a copy of the GNU General Public License
17  *  along with this program; if not, write to the Free Software
18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19  */
20 #include <linux/idr.h>
21 #include <linux/device.h>
22 #include <linux/err.h>
23 #include <linux/init.h>
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/posix-clock.h>
27 #include <linux/pps_kernel.h>
28 #include <linux/slab.h>
29 #include <linux/syscalls.h>
30 #include <linux/uaccess.h>
31 #include <uapi/linux/sched/types.h>
32 
33 #include "ptp_private.h"
34 
35 #define PTP_MAX_ALARMS 4
36 #define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT)
37 #define PTP_PPS_EVENT PPS_CAPTUREASSERT
38 #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)
39 
40 /* private globals */
41 
42 static dev_t ptp_devt;
43 static struct class *ptp_class;
44 
45 static DEFINE_IDA(ptp_clocks_map);
46 
47 /* time stamp event queue operations */
48 
49 static inline int queue_free(struct timestamp_event_queue *q)
50 {
51 	return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
52 }
53 
54 static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
55 				       struct ptp_clock_event *src)
56 {
57 	struct ptp_extts_event *dst;
58 	unsigned long flags;
59 	s64 seconds;
60 	u32 remainder;
61 
62 	seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
63 
64 	spin_lock_irqsave(&queue->lock, flags);
65 
66 	dst = &queue->buf[queue->tail];
67 	dst->index = src->index;
68 	dst->t.sec = seconds;
69 	dst->t.nsec = remainder;
70 
71 	if (!queue_free(queue))
72 		queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
73 
74 	queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;
75 
76 	spin_unlock_irqrestore(&queue->lock, flags);
77 }
78 
79 static s32 scaled_ppm_to_ppb(long ppm)
80 {
81 	/*
82 	 * The 'freq' field in the 'struct timex' is in parts per
83 	 * million, but with a 16 bit binary fractional field.
84 	 *
85 	 * We want to calculate
86 	 *
87 	 *    ppb = scaled_ppm * 1000 / 2^16
88 	 *
89 	 * which simplifies to
90 	 *
91 	 *    ppb = scaled_ppm * 125 / 2^13
92 	 */
93 	s64 ppb = 1 + ppm;
94 	ppb *= 125;
95 	ppb >>= 13;
96 	return (s32) ppb;
97 }
98 
99 /* posix clock implementation */
100 
101 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
102 {
103 	tp->tv_sec = 0;
104 	tp->tv_nsec = 1;
105 	return 0;
106 }
107 
108 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
109 {
110 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
111 
112 	return  ptp->info->settime64(ptp->info, tp);
113 }
114 
115 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
116 {
117 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
118 	int err;
119 
120 	err = ptp->info->gettime64(ptp->info, tp);
121 	return err;
122 }
123 
124 static int ptp_clock_adjtime(struct posix_clock *pc, struct timex *tx)
125 {
126 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
127 	struct ptp_clock_info *ops;
128 	int err = -EOPNOTSUPP;
129 
130 	ops = ptp->info;
131 
132 	if (tx->modes & ADJ_SETOFFSET) {
133 		struct timespec64 ts;
134 		ktime_t kt;
135 		s64 delta;
136 
137 		ts.tv_sec  = tx->time.tv_sec;
138 		ts.tv_nsec = tx->time.tv_usec;
139 
140 		if (!(tx->modes & ADJ_NANO))
141 			ts.tv_nsec *= 1000;
142 
143 		if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
144 			return -EINVAL;
145 
146 		kt = timespec64_to_ktime(ts);
147 		delta = ktime_to_ns(kt);
148 		err = ops->adjtime(ops, delta);
149 	} else if (tx->modes & ADJ_FREQUENCY) {
150 		s32 ppb = scaled_ppm_to_ppb(tx->freq);
151 		if (ppb > ops->max_adj || ppb < -ops->max_adj)
152 			return -ERANGE;
153 		if (ops->adjfine)
154 			err = ops->adjfine(ops, tx->freq);
155 		else
156 			err = ops->adjfreq(ops, ppb);
157 		ptp->dialed_frequency = tx->freq;
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 delete_ptp_clock(struct posix_clock *pc)
179 {
180 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
181 
182 	mutex_destroy(&ptp->tsevq_mux);
183 	mutex_destroy(&ptp->pincfg_mux);
184 	ida_simple_remove(&ptp_clocks_map, ptp->index);
185 	kfree(ptp);
186 }
187 
188 static void ptp_aux_kworker(struct kthread_work *work)
189 {
190 	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
191 					     aux_work.work);
192 	struct ptp_clock_info *info = ptp->info;
193 	long delay;
194 
195 	delay = info->do_aux_work(info);
196 
197 	if (delay >= 0)
198 		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
199 }
200 
201 /* public interface */
202 
203 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
204 				     struct device *parent)
205 {
206 	struct ptp_clock *ptp;
207 	int err = 0, index, major = MAJOR(ptp_devt);
208 
209 	if (info->n_alarm > PTP_MAX_ALARMS)
210 		return ERR_PTR(-EINVAL);
211 
212 	/* Initialize a clock structure. */
213 	err = -ENOMEM;
214 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
215 	if (ptp == NULL)
216 		goto no_memory;
217 
218 	index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
219 	if (index < 0) {
220 		err = index;
221 		goto no_slot;
222 	}
223 
224 	ptp->clock.ops = ptp_clock_ops;
225 	ptp->clock.release = delete_ptp_clock;
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 		char *worker_name = kasprintf(GFP_KERNEL, "ptp%d", ptp->index);
236 
237 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
238 		ptp->kworker = kthread_create_worker(0, worker_name ?
239 						     worker_name : info->name);
240 		kfree(worker_name);
241 		if (IS_ERR(ptp->kworker)) {
242 			err = PTR_ERR(ptp->kworker);
243 			pr_err("failed to create ptp aux_worker %d\n", err);
244 			goto kworker_err;
245 		}
246 	}
247 
248 	err = ptp_populate_pin_groups(ptp);
249 	if (err)
250 		goto no_pin_groups;
251 
252 	/* Create a new device in our class. */
253 	ptp->dev = device_create_with_groups(ptp_class, parent, ptp->devid,
254 					     ptp, ptp->pin_attr_groups,
255 					     "ptp%d", ptp->index);
256 	if (IS_ERR(ptp->dev))
257 		goto no_device;
258 
259 	/* Register a new PPS source. */
260 	if (info->pps) {
261 		struct pps_source_info pps;
262 		memset(&pps, 0, sizeof(pps));
263 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
264 		pps.mode = PTP_PPS_MODE;
265 		pps.owner = info->owner;
266 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
267 		if (!ptp->pps_source) {
268 			pr_err("failed to register pps source\n");
269 			goto no_pps;
270 		}
271 	}
272 
273 	/* Create a posix clock. */
274 	err = posix_clock_register(&ptp->clock, ptp->devid);
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 	device_destroy(ptp_class, ptp->devid);
287 no_device:
288 	ptp_cleanup_pin_groups(ptp);
289 no_pin_groups:
290 	if (ptp->kworker)
291 		kthread_destroy_worker(ptp->kworker);
292 kworker_err:
293 	mutex_destroy(&ptp->tsevq_mux);
294 	mutex_destroy(&ptp->pincfg_mux);
295 	ida_simple_remove(&ptp_clocks_map, index);
296 no_slot:
297 	kfree(ptp);
298 no_memory:
299 	return ERR_PTR(err);
300 }
301 EXPORT_SYMBOL(ptp_clock_register);
302 
303 int ptp_clock_unregister(struct ptp_clock *ptp)
304 {
305 	ptp->defunct = 1;
306 	wake_up_interruptible(&ptp->tsev_wq);
307 
308 	if (ptp->kworker) {
309 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
310 		kthread_destroy_worker(ptp->kworker);
311 	}
312 
313 	/* Release the clock's resources. */
314 	if (ptp->pps_source)
315 		pps_unregister_source(ptp->pps_source);
316 
317 	device_destroy(ptp_class, ptp->devid);
318 	ptp_cleanup_pin_groups(ptp);
319 
320 	posix_clock_unregister(&ptp->clock);
321 	return 0;
322 }
323 EXPORT_SYMBOL(ptp_clock_unregister);
324 
325 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
326 {
327 	struct pps_event_time evt;
328 
329 	switch (event->type) {
330 
331 	case PTP_CLOCK_ALARM:
332 		break;
333 
334 	case PTP_CLOCK_EXTTS:
335 		enqueue_external_timestamp(&ptp->tsevq, event);
336 		wake_up_interruptible(&ptp->tsev_wq);
337 		break;
338 
339 	case PTP_CLOCK_PPS:
340 		pps_get_ts(&evt);
341 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
342 		break;
343 
344 	case PTP_CLOCK_PPSUSR:
345 		pps_event(ptp->pps_source, &event->pps_times,
346 			  PTP_PPS_EVENT, NULL);
347 		break;
348 	}
349 }
350 EXPORT_SYMBOL(ptp_clock_event);
351 
352 int ptp_clock_index(struct ptp_clock *ptp)
353 {
354 	return ptp->index;
355 }
356 EXPORT_SYMBOL(ptp_clock_index);
357 
358 int ptp_find_pin(struct ptp_clock *ptp,
359 		 enum ptp_pin_function func, unsigned int chan)
360 {
361 	struct ptp_pin_desc *pin = NULL;
362 	int i;
363 
364 	mutex_lock(&ptp->pincfg_mux);
365 	for (i = 0; i < ptp->info->n_pins; i++) {
366 		if (ptp->info->pin_config[i].func == func &&
367 		    ptp->info->pin_config[i].chan == chan) {
368 			pin = &ptp->info->pin_config[i];
369 			break;
370 		}
371 	}
372 	mutex_unlock(&ptp->pincfg_mux);
373 
374 	return pin ? i : -1;
375 }
376 EXPORT_SYMBOL(ptp_find_pin);
377 
378 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
379 {
380 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
381 }
382 EXPORT_SYMBOL(ptp_schedule_worker);
383 
384 /* module operations */
385 
386 static void __exit ptp_exit(void)
387 {
388 	class_destroy(ptp_class);
389 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
390 	ida_destroy(&ptp_clocks_map);
391 }
392 
393 static int __init ptp_init(void)
394 {
395 	int err;
396 
397 	ptp_class = class_create(THIS_MODULE, "ptp");
398 	if (IS_ERR(ptp_class)) {
399 		pr_err("ptp: failed to allocate class\n");
400 		return PTR_ERR(ptp_class);
401 	}
402 
403 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
404 	if (err < 0) {
405 		pr_err("ptp: failed to allocate device region\n");
406 		goto no_region;
407 	}
408 
409 	ptp_class->dev_groups = ptp_groups;
410 	pr_info("PTP clock support registered\n");
411 	return 0;
412 
413 no_region:
414 	class_destroy(ptp_class);
415 	return err;
416 }
417 
418 subsys_initcall(ptp_init);
419 module_exit(ptp_exit);
420 
421 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
422 MODULE_DESCRIPTION("PTP clocks support");
423 MODULE_LICENSE("GPL");
424