summaryrefslogtreecommitdiffstats
path: root/drivers/pps/kapi.c
blob: e8847c118ea38d5fd0631ea1636e8c2d12fc204e (plain)
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
/*
 * kernel API
 *
 *
 * Copyright (C) 2005-2009   Rodolfo Giometti <giometti@linux.it>
 *
 *   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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/spinlock.h>
#include <linux/idr.h>
#include <linux/fs.h>
#include <linux/pps_kernel.h>
#include <linux/slab.h>

/*
 * Local variables
 */

static DEFINE_SPINLOCK(pps_idr_lock);
static DEFINE_IDR(pps_idr);

/*
 * Local functions
 */

static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset)
{
	ts->nsec += offset->nsec;
	while (ts->nsec >= NSEC_PER_SEC) {
		ts->nsec -= NSEC_PER_SEC;
		ts->sec++;
	}
	while (ts->nsec < 0) {
		ts->nsec += NSEC_PER_SEC;
		ts->sec--;
	}
	ts->sec += offset->sec;
}

/*
 * Exported functions
 */

/* pps_register_source - add a PPS source in the system
 * @info: the PPS info struct
 * @default_params: the default PPS parameters of the new source
 *
 * This function is used to add a new PPS source in the system. The new
 * source is described by info's fields and it will have, as default PPS
 * parameters, the ones specified into default_params.
 *
 * The function returns, in case of success, the PPS device. Otherwise NULL.
 */

struct pps_device *pps_register_source(struct pps_source_info *info,
		int default_params)
{
	struct pps_device *pps;
	int id;
	int err;

	/* Sanity checks */
	if ((info->mode & default_params) != default_params) {
		pr_err("%s: unsupported default parameters\n",
					info->name);
		err = -EINVAL;
		goto pps_register_source_exit;
	}
	if ((info->mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) != 0 &&
			info->echo == NULL) {
		pr_err("%s: echo function is not defined\n",
					info->name);
		err = -EINVAL;
		goto pps_register_source_exit;
	}
	if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
		pr_err("%s: unspecified time format\n",
					info->name);
		err = -EINVAL;
		goto pps_register_source_exit;
	}

	/* Allocate memory for the new PPS source struct */
	pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL);
	if (pps == NULL) {
		err = -ENOMEM;
		goto pps_register_source_exit;
	}

	/* These initializations must be done before calling idr_get_new()
	 * in order to avoid reces into pps_event().
	 */
	pps->params.api_version = PPS_API_VERS;
	pps->params.mode = default_params;
	pps->info = *info;

	init_waitqueue_head(&pps->queue);
	spin_lock_init(&pps->lock);

	/* Get new ID for the new PPS source */
	if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0) {
		err = -ENOMEM;
		goto kfree_pps;
	}

	spin_lock_irq(&pps_idr_lock);

	/* Now really allocate the PPS source.
	 * After idr_get_new() calling the new source will be freely available
	 * into the kernel.
	 */
	err = idr_get_new(&pps_idr, pps, &id);
	if (err < 0) {
		spin_unlock_irq(&pps_idr_lock);
		goto kfree_pps;
	}

	id = id & MAX_ID_MASK;
	if (id >= PPS_MAX_SOURCES) {
		spin_unlock_irq(&pps_idr_lock);

		pr_err("%s: too many PPS sources in the system\n",
					info->name);
		err = -EBUSY;
		goto free_idr;
	}
	pps->id = id;

	spin_unlock_irq(&pps_idr_lock);

	/* Create the char device */
	err = pps_register_cdev(pps);
	if (err < 0) {
		pr_err("%s: unable to create char device\n",
					info->name);
		goto free_idr;
	}

	dev_info(pps->dev, "new PPS source %s\n", info->name);

	return pps;

free_idr:
	spin_lock_irq(&pps_idr_lock);
	idr_remove(&pps_idr, id);
	spin_unlock_irq(&pps_idr_lock);

kfree_pps:
	kfree(pps);

pps_register_source_exit:
	pr_err("%s: unable to register source\n", info->name);

	return NULL;
}
EXPORT_SYMBOL(pps_register_source);

/* pps_unregister_source - remove a PPS source from the system
 * @pps: the PPS source
 *
 * This function is used to remove a previously registered PPS source from
 * the system.
 */

void pps_unregister_source(struct pps_device *pps)
{
	unsigned int id = pps->id;

	pps_unregister_cdev(pps);

	spin_lock_irq(&pps_idr_lock);
	idr_remove(&pps_idr, pps->id);
	spin_unlock_irq(&pps_idr_lock);

	kfree(pps);
}
EXPORT_SYMBOL(pps_unregister_source);

/* pps_event - register a PPS event into the system
 * @pps: the PPS device
 * @ts: the event timestamp
 * @event: the event type
 * @data: userdef pointer
 *
 * This function is used by each PPS client in order to register a new
 * PPS event into the system (it's usually called inside an IRQ handler).
 *
 * If an echo function is associated with the PPS device it will be called
 * as:
 *	pps->info.echo(pps, event, data);
 */
void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event,
		void *data)
{
	unsigned long flags;
	int captured = 0;
	struct pps_ktime ts_real;

	if ((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0) {
		dev_err(pps->dev, "unknown event (%x)\n", event);
		return;
	}

	dev_dbg(pps->dev, "PPS event at %ld.%09ld\n",
			ts->ts_real.tv_sec, ts->ts_real.tv_nsec);

	timespec_to_pps_ktime(&ts_real, ts->ts_real);

	spin_lock_irqsave(&pps->lock, flags);

	/* Must call the echo function? */
	if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)))
		pps->info.echo(pps, event, data);

	/* Check the event */
	pps->current_mode = pps->params.mode;
	if ((event & PPS_CAPTUREASSERT) &
			(pps->params.mode & PPS_CAPTUREASSERT)) {
		/* We have to add an offset? */
		if (pps->params.mode & PPS_OFFSETASSERT)
			pps_add_offset(&ts_real,
					&pps->params.assert_off_tu);

		/* Save the time stamp */
		pps->assert_tu = ts_real;
		pps->assert_sequence++;
		dev_dbg(pps->dev, "capture assert seq #%u\n",
			pps->assert_sequence);

		captured = ~0;
	}
	if ((event & PPS_CAPTURECLEAR) &
			(pps->params.mode & PPS_CAPTURECLEAR)) {
		/* We have to add an offset? */
		if (pps->params.mode & PPS_OFFSETCLEAR)
			pps_add_offset(&ts_real,
					&pps->params.clear_off_tu);

		/* Save the time stamp */
		pps->clear_tu = ts_real;
		pps->clear_sequence++;
		dev_dbg(pps->dev, "capture clear seq #%u\n",
			pps->clear_sequence);

		captured = ~0;
	}

	/* Wake up if captured something */
	if (captured) {
		pps->last_ev++;
		wake_up_interruptible_all(&pps->queue);

		kill_fasync(&pps->async_queue, SIGIO, POLL_IN);
	}

	spin_unlock_irqrestore(&pps->lock, flags);
}
EXPORT_SYMBOL(pps_event);
OpenPOWER on IntegriCloud