aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/ptp/ptp_clock.c
blob: e25d2bc898e5b6e4eb7b43e6df87129a2a19781e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
/*
 * PTP 1588 clock support
 *
 * Copyright (C) 2010 OMICRON electronics GmbH
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include <linux/idr.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/posix-clock.h>
#include <linux/pps_kernel.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>

#include "ptp_private.h"

#define PTP_MAX_ALARMS 4
#define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT)
#define PTP_PPS_EVENT PPS_CAPTUREASSERT
#define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)

/* private globals */

static dev_t ptp_devt;
static struct class *ptp_class;

static DEFINE_IDA(ptp_clocks_map);

/* time stamp event queue operations */

static inline int queue_free(struct timestamp_event_queue *q)
{
	return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
}

static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
				       struct ptp_clock_event *src)
{
	struct ptp_extts_event *dst;
	unsigned long flags;
	s64 seconds;
	u32 remainder;

	seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);

	spin_lock_irqsave(&queue->lock, flags);

	dst = &queue->buf[queue->tail];
	dst->index = src->index;
	dst->t.sec = seconds;
	dst->t.nsec = remainder;

	if (!queue_free(queue))
		queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;

	queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;

	spin_unlock_irqrestore(&queue->lock, flags);
}

static s32 scaled_ppm_to_ppb(long ppm)
{
	/*
	 * The 'freq' field in the 'struct timex' is in parts per
	 * million, but with a 16 bit binary fractional field.
	 *
	 * We want to calculate
	 *
	 *    ppb = scaled_ppm * 1000 / 2^16
	 *
	 * which simplifies to
	 *
	 *    ppb = scaled_ppm * 125 / 2^13
	 */
	s64 ppb = 1 + ppm;
	ppb *= 125;
	ppb >>= 13;
	return (s32) ppb;
}

/* posix clock implementation */

static int ptp_clock_getres(struct posix_clock *pc, struct timespec *tp)
{
	tp->tv_sec = 0;
	tp->tv_nsec = 1;
	return 0;
}

static int ptp_clock_settime(struct posix_clock *pc, const struct timespec *tp)
{
	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
	return ptp->info->settime(ptp->info, tp);
}

static int ptp_clock_gettime(struct posix_clock *pc, struct timespec *tp)
{
	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
	return ptp->info->gettime(ptp->info, tp);
}

static int ptp_clock_adjtime(struct posix_clock *pc, struct timex *tx)
{
	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
	struct ptp_clock_info *ops;
	int err = -EOPNOTSUPP;

	ops = ptp->info;

	if (tx->modes & ADJ_SETOFFSET) {
		struct timespec ts;
		ktime_t kt;
		s64 delta;

		ts.tv_sec  = tx->time.tv_sec;
		ts.tv_nsec = tx->time.tv_usec;

		if (!(tx->modes & ADJ_NANO))
			ts.tv_nsec *= 1000;

		if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
			return -EINVAL;

		kt = timespec_to_ktime(ts);
		delta = ktime_to_ns(kt);
		err = ops->adjtime(ops, delta);
	} else if (tx->modes & ADJ_FREQUENCY) {
		err = ops->adjfreq(ops, scaled_ppm_to_ppb(tx->freq));
		ptp->dialed_frequency = tx->freq;
	} else if (tx->modes == 0) {
		tx->freq = ptp->dialed_frequency;
		err = 0;
	}

	return err;
}

static struct posix_clock_operations ptp_clock_ops = {
	.owner		= THIS_MODULE,
	.clock_adjtime	= ptp_clock_adjtime,
	.clock_gettime	= ptp_clock_gettime,
	.clock_getres	= ptp_clock_getres,
	.clock_settime	= ptp_clock_settime,
	.ioctl		= ptp_ioctl,
	.open		= ptp_open,
	.poll		= ptp_poll,
	.read		= ptp_read,
};

static void delete_ptp_clock(struct posix_clock *pc)
{
	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);

	mutex_destroy(&ptp->tsevq_mux);
	mutex_destroy(&ptp->pincfg_mux);
	ida_simple_remove(&ptp_clocks_map, ptp->index);
	kfree(ptp);
}

/* public interface */

struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
				     struct device *parent)
{
	struct ptp_clock *ptp;
	int err = 0, index, major = MAJOR(ptp_devt);

	if (info->n_alarm > PTP_MAX_ALARMS)
		return ERR_PTR(-EINVAL);

	/* Initialize a clock structure. */
	err = -ENOMEM;
	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
	if (ptp == NULL)
		goto no_memory;

	index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
	if (index < 0) {
		err = index;
		goto no_slot;
	}

	ptp->clock.ops = ptp_clock_ops;
	ptp->clock.release = delete_ptp_clock;
	ptp->info = info;
	ptp->devid = MKDEV(major, index);
	ptp->index = index;
	spin_lock_init(&ptp->tsevq.lock);
	mutex_init(&ptp->tsevq_mux);
	mutex_init(&ptp->pincfg_mux);
	init_waitqueue_head(&ptp->tsev_wq);

	/* Create a new device in our class. */
	ptp->dev = device_create(ptp_class, parent, ptp->devid, ptp,
				 "ptp%d", ptp->index);
	if (IS_ERR(ptp->dev))
		goto no_device;

	dev_set_drvdata(ptp->dev, ptp);

	err = ptp_populate_sysfs(ptp);
	if (err)
		goto no_sysfs;

	/* Register a new PPS source. */
	if (info->pps) {
		struct pps_source_info pps;
		memset(&pps, 0, sizeof(pps));
		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
		pps.mode = PTP_PPS_MODE;
		pps.owner = info->owner;
		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
		if (!ptp->pps_source) {
			pr_err("failed to register pps source\n");
			goto no_pps;
		}
	}

	/* Create a posix clock. */
	err = posix_clock_register(&ptp->clock, ptp->devid);
	if (err) {
		pr_err("failed to create posix clock\n");
		goto no_clock;
	}

	return ptp;

no_clock:
	if (ptp->pps_source)
		pps_unregister_source(ptp->pps_source);
no_pps:
	ptp_cleanup_sysfs(ptp);
no_sysfs:
	device_destroy(ptp_class, ptp->devid);
no_device:
	mutex_destroy(&ptp->tsevq_mux);
	mutex_destroy(&ptp->pincfg_mux);
no_slot:
	kfree(ptp);
no_memory:
	return ERR_PTR(err);
}
EXPORT_SYMBOL(ptp_clock_register);

int ptp_clock_unregister(struct ptp_clock *ptp)
{
	ptp->defunct = 1;
	wake_up_interruptible(&ptp->tsev_wq);

	/* Release the clock's resources. */
	if (ptp->pps_source)
		pps_unregister_source(ptp->pps_source);
	ptp_cleanup_sysfs(ptp);
	device_destroy(ptp_class, ptp->devid);

	posix_clock_unregister(&ptp->clock);
	return 0;
}
EXPORT_SYMBOL(ptp_clock_unregister);

void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
{
	struct pps_event_time evt;

	switch (event->type) {

	case PTP_CLOCK_ALARM:
		break;

	case PTP_CLOCK_EXTTS:
		enqueue_external_timestamp(&ptp->tsevq, event);
		wake_up_interruptible(&ptp->tsev_wq);
		break;

	case PTP_CLOCK_PPS:
		pps_get_ts(&evt);
		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
		break;

	case PTP_CLOCK_PPSUSR:
		pps_event(ptp->pps_source, &event->pps_times,
			  PTP_PPS_EVENT, NULL);
		break;
	}
}
EXPORT_SYMBOL(ptp_clock_event);

int ptp_clock_index(struct ptp_clock *ptp)
{
	return ptp->index;
}
EXPORT_SYMBOL(ptp_clock_index);

int ptp_find_pin(struct ptp_clock *ptp,
		 enum ptp_pin_function func, unsigned int chan)
{
	struct ptp_pin_desc *pin = NULL;
	int i;

	mutex_lock(&ptp->pincfg_mux);
	for (i = 0; i < ptp->info->n_pins; i++) {
		if (ptp->info->pin_config[i].func == func &&
		    ptp->info->pin_config[i].chan == chan) {
			pin = &ptp->info->pin_config[i];
			break;
		}
	}
	mutex_unlock(&ptp->pincfg_mux);

	return pin ? i : -1;
}
EXPORT_SYMBOL(ptp_find_pin);

/* module operations */

static void __exit ptp_exit(void)
{
	class_destroy(ptp_class);
	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
	ida_destroy(&ptp_clocks_map);
}

static int __init ptp_init(void)
{
	int err;

	ptp_class = class_create(THIS_MODULE, "ptp");
	if (IS_ERR(ptp_class)) {
		pr_err("ptp: failed to allocate class\n");
		return PTR_ERR(ptp_class);
	}

	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
	if (err < 0) {
		pr_err("ptp: failed to allocate device region\n");
		goto no_region;
	}

	ptp_class->dev_groups = ptp_groups;
	pr_info("PTP clock support registered\n");
	return 0;

no_region:
	class_destroy(ptp_class);
	return err;
}

subsys_initcall(ptp_init);
module_exit(ptp_exit);

MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
MODULE_DESCRIPTION("PTP clocks support");
MODULE_LICENSE("GPL");