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Richard Cochrand94ba802011-04-22 12:03:08 +02001/*
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/bitops.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
32#include "ptp_private.h"
33
34#define PTP_MAX_ALARMS 4
35#define PTP_MAX_CLOCKS 8
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
42static dev_t ptp_devt;
43static struct class *ptp_class;
44
45static DECLARE_BITMAP(ptp_clocks_map, PTP_MAX_CLOCKS);
46static DEFINE_MUTEX(ptp_clocks_mutex); /* protects 'ptp_clocks_map' */
47
48/* time stamp event queue operations */
49
50static inline int queue_free(struct timestamp_event_queue *q)
51{
52 return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
53}
54
55static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
56 struct ptp_clock_event *src)
57{
58 struct ptp_extts_event *dst;
59 unsigned long flags;
60 s64 seconds;
61 u32 remainder;
62
63 seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
64
65 spin_lock_irqsave(&queue->lock, flags);
66
67 dst = &queue->buf[queue->tail];
68 dst->index = src->index;
69 dst->t.sec = seconds;
70 dst->t.nsec = remainder;
71
72 if (!queue_free(queue))
73 queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
74
75 queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;
76
77 spin_unlock_irqrestore(&queue->lock, flags);
78}
79
80static s32 scaled_ppm_to_ppb(long ppm)
81{
82 /*
83 * The 'freq' field in the 'struct timex' is in parts per
84 * million, but with a 16 bit binary fractional field.
85 *
86 * We want to calculate
87 *
88 * ppb = scaled_ppm * 1000 / 2^16
89 *
90 * which simplifies to
91 *
92 * ppb = scaled_ppm * 125 / 2^13
93 */
94 s64 ppb = 1 + ppm;
95 ppb *= 125;
96 ppb >>= 13;
97 return (s32) ppb;
98}
99
100/* posix clock implementation */
101
102static int ptp_clock_getres(struct posix_clock *pc, struct timespec *tp)
103{
Thomas Gleixnerd68fb112011-12-05 21:16:06 +0100104 tp->tv_sec = 0;
105 tp->tv_nsec = 1;
106 return 0;
Richard Cochrand94ba802011-04-22 12:03:08 +0200107}
108
109static int ptp_clock_settime(struct posix_clock *pc, const struct timespec *tp)
110{
111 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
112 return ptp->info->settime(ptp->info, tp);
113}
114
115static int ptp_clock_gettime(struct posix_clock *pc, struct timespec *tp)
116{
117 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
118 return ptp->info->gettime(ptp->info, tp);
119}
120
121static int ptp_clock_adjtime(struct posix_clock *pc, struct timex *tx)
122{
123 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
124 struct ptp_clock_info *ops;
125 int err = -EOPNOTSUPP;
126
127 ops = ptp->info;
128
129 if (tx->modes & ADJ_SETOFFSET) {
130 struct timespec ts;
131 ktime_t kt;
132 s64 delta;
133
134 ts.tv_sec = tx->time.tv_sec;
135 ts.tv_nsec = tx->time.tv_usec;
136
137 if (!(tx->modes & ADJ_NANO))
138 ts.tv_nsec *= 1000;
139
140 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
141 return -EINVAL;
142
143 kt = timespec_to_ktime(ts);
144 delta = ktime_to_ns(kt);
145 err = ops->adjtime(ops, delta);
Richard Cochrand94ba802011-04-22 12:03:08 +0200146 } else if (tx->modes & ADJ_FREQUENCY) {
Richard Cochrand94ba802011-04-22 12:03:08 +0200147 err = ops->adjfreq(ops, scaled_ppm_to_ppb(tx->freq));
Richard Cochran39a8cbd2012-09-22 07:02:01 +0000148 ptp->dialed_frequency = tx->freq;
Richard Cochran5c35bad2012-09-22 07:02:02 +0000149 } else if (tx->modes == 0) {
150 tx->freq = ptp->dialed_frequency;
151 err = 0;
Richard Cochrand94ba802011-04-22 12:03:08 +0200152 }
153
154 return err;
155}
156
157static struct posix_clock_operations ptp_clock_ops = {
158 .owner = THIS_MODULE,
159 .clock_adjtime = ptp_clock_adjtime,
160 .clock_gettime = ptp_clock_gettime,
161 .clock_getres = ptp_clock_getres,
162 .clock_settime = ptp_clock_settime,
163 .ioctl = ptp_ioctl,
164 .open = ptp_open,
165 .poll = ptp_poll,
166 .read = ptp_read,
167};
168
169static void delete_ptp_clock(struct posix_clock *pc)
170{
171 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
172
173 mutex_destroy(&ptp->tsevq_mux);
174
175 /* Remove the clock from the bit map. */
176 mutex_lock(&ptp_clocks_mutex);
177 clear_bit(ptp->index, ptp_clocks_map);
178 mutex_unlock(&ptp_clocks_mutex);
179
180 kfree(ptp);
181}
182
183/* public interface */
184
Richard Cochran1ef76152012-09-22 07:02:03 +0000185struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
186 struct device *parent)
Richard Cochrand94ba802011-04-22 12:03:08 +0200187{
188 struct ptp_clock *ptp;
189 int err = 0, index, major = MAJOR(ptp_devt);
190
191 if (info->n_alarm > PTP_MAX_ALARMS)
192 return ERR_PTR(-EINVAL);
193
194 /* Find a free clock slot and reserve it. */
195 err = -EBUSY;
196 mutex_lock(&ptp_clocks_mutex);
197 index = find_first_zero_bit(ptp_clocks_map, PTP_MAX_CLOCKS);
198 if (index < PTP_MAX_CLOCKS)
199 set_bit(index, ptp_clocks_map);
200 else
201 goto no_slot;
202
203 /* Initialize a clock structure. */
204 err = -ENOMEM;
205 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
206 if (ptp == NULL)
207 goto no_memory;
208
209 ptp->clock.ops = ptp_clock_ops;
210 ptp->clock.release = delete_ptp_clock;
211 ptp->info = info;
212 ptp->devid = MKDEV(major, index);
213 ptp->index = index;
214 spin_lock_init(&ptp->tsevq.lock);
215 mutex_init(&ptp->tsevq_mux);
216 init_waitqueue_head(&ptp->tsev_wq);
217
218 /* Create a new device in our class. */
Richard Cochran1ef76152012-09-22 07:02:03 +0000219 ptp->dev = device_create(ptp_class, parent, ptp->devid, ptp,
Richard Cochrand94ba802011-04-22 12:03:08 +0200220 "ptp%d", ptp->index);
221 if (IS_ERR(ptp->dev))
222 goto no_device;
223
224 dev_set_drvdata(ptp->dev, ptp);
225
226 err = ptp_populate_sysfs(ptp);
227 if (err)
228 goto no_sysfs;
229
230 /* Register a new PPS source. */
231 if (info->pps) {
232 struct pps_source_info pps;
233 memset(&pps, 0, sizeof(pps));
234 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
235 pps.mode = PTP_PPS_MODE;
236 pps.owner = info->owner;
237 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
238 if (!ptp->pps_source) {
239 pr_err("failed to register pps source\n");
240 goto no_pps;
241 }
242 }
243
244 /* Create a posix clock. */
245 err = posix_clock_register(&ptp->clock, ptp->devid);
246 if (err) {
247 pr_err("failed to create posix clock\n");
248 goto no_clock;
249 }
250
251 mutex_unlock(&ptp_clocks_mutex);
252 return ptp;
253
254no_clock:
255 if (ptp->pps_source)
256 pps_unregister_source(ptp->pps_source);
257no_pps:
258 ptp_cleanup_sysfs(ptp);
259no_sysfs:
260 device_destroy(ptp_class, ptp->devid);
261no_device:
262 mutex_destroy(&ptp->tsevq_mux);
263 kfree(ptp);
264no_memory:
265 clear_bit(index, ptp_clocks_map);
266no_slot:
267 mutex_unlock(&ptp_clocks_mutex);
268 return ERR_PTR(err);
269}
270EXPORT_SYMBOL(ptp_clock_register);
271
272int ptp_clock_unregister(struct ptp_clock *ptp)
273{
274 ptp->defunct = 1;
275 wake_up_interruptible(&ptp->tsev_wq);
276
277 /* Release the clock's resources. */
278 if (ptp->pps_source)
279 pps_unregister_source(ptp->pps_source);
280 ptp_cleanup_sysfs(ptp);
281 device_destroy(ptp_class, ptp->devid);
282
283 posix_clock_unregister(&ptp->clock);
284 return 0;
285}
286EXPORT_SYMBOL(ptp_clock_unregister);
287
288void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
289{
290 struct pps_event_time evt;
291
292 switch (event->type) {
293
294 case PTP_CLOCK_ALARM:
295 break;
296
297 case PTP_CLOCK_EXTTS:
298 enqueue_external_timestamp(&ptp->tsevq, event);
299 wake_up_interruptible(&ptp->tsev_wq);
300 break;
301
302 case PTP_CLOCK_PPS:
303 pps_get_ts(&evt);
304 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
305 break;
Ben Hutchings220a60a2012-09-03 11:34:58 +0100306
307 case PTP_CLOCK_PPSUSR:
308 pps_event(ptp->pps_source, &event->pps_times,
309 PTP_PPS_EVENT, NULL);
310 break;
Richard Cochrand94ba802011-04-22 12:03:08 +0200311 }
312}
313EXPORT_SYMBOL(ptp_clock_event);
314
Richard Cochran995a9092012-04-03 22:59:16 +0000315int ptp_clock_index(struct ptp_clock *ptp)
316{
317 return ptp->index;
318}
319EXPORT_SYMBOL(ptp_clock_index);
320
Richard Cochrand94ba802011-04-22 12:03:08 +0200321/* module operations */
322
323static void __exit ptp_exit(void)
324{
325 class_destroy(ptp_class);
326 unregister_chrdev_region(ptp_devt, PTP_MAX_CLOCKS);
327}
328
329static int __init ptp_init(void)
330{
331 int err;
332
333 ptp_class = class_create(THIS_MODULE, "ptp");
334 if (IS_ERR(ptp_class)) {
335 pr_err("ptp: failed to allocate class\n");
336 return PTR_ERR(ptp_class);
337 }
338
339 err = alloc_chrdev_region(&ptp_devt, 0, PTP_MAX_CLOCKS, "ptp");
340 if (err < 0) {
341 pr_err("ptp: failed to allocate device region\n");
342 goto no_region;
343 }
344
345 ptp_class->dev_attrs = ptp_dev_attrs;
346 pr_info("PTP clock support registered\n");
347 return 0;
348
349no_region:
350 class_destroy(ptp_class);
351 return err;
352}
353
354subsys_initcall(ptp_init);
355module_exit(ptp_exit);
356
Richard Cochranc2ec3ff2012-03-16 22:39:29 +0000357MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
Richard Cochrand94ba802011-04-22 12:03:08 +0200358MODULE_DESCRIPTION("PTP clocks support");
359MODULE_LICENSE("GPL");