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
queue_free(struct timestamp_event_queue * q)49 static inline int queue_free(struct timestamp_event_queue *q)
50 {
51 return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
52 }
53
enqueue_external_timestamp(struct timestamp_event_queue * queue,struct ptp_clock_event * src)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
scaled_ppm_to_ppb(long ppm)79 long 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 (long) ppb;
97 }
98 EXPORT_SYMBOL(scaled_ppm_to_ppb);
99
100 /* posix clock implementation */
101
ptp_clock_getres(struct posix_clock * pc,struct timespec64 * tp)102 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
103 {
104 tp->tv_sec = 0;
105 tp->tv_nsec = 1;
106 return 0;
107 }
108
ptp_clock_settime(struct posix_clock * pc,const struct timespec64 * tp)109 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
110 {
111 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
112
113 return ptp->info->settime64(ptp->info, tp);
114 }
115
ptp_clock_gettime(struct posix_clock * pc,struct timespec64 * tp)116 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
117 {
118 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
119 int err;
120
121 err = ptp->info->gettime64(ptp->info, tp);
122 return err;
123 }
124
ptp_clock_adjtime(struct posix_clock * pc,struct timex * tx)125 static int ptp_clock_adjtime(struct posix_clock *pc, struct timex *tx)
126 {
127 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
128 struct ptp_clock_info *ops;
129 int err = -EOPNOTSUPP;
130
131 ops = ptp->info;
132
133 if (tx->modes & ADJ_SETOFFSET) {
134 struct timespec64 ts;
135 ktime_t kt;
136 s64 delta;
137
138 ts.tv_sec = tx->time.tv_sec;
139 ts.tv_nsec = tx->time.tv_usec;
140
141 if (!(tx->modes & ADJ_NANO))
142 ts.tv_nsec *= 1000;
143
144 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
145 return -EINVAL;
146
147 kt = timespec64_to_ktime(ts);
148 delta = ktime_to_ns(kt);
149 err = ops->adjtime(ops, delta);
150 } else if (tx->modes & ADJ_FREQUENCY) {
151 long ppb = scaled_ppm_to_ppb(tx->freq);
152 if (ppb > ops->max_adj || ppb < -ops->max_adj)
153 return -ERANGE;
154 if (ops->adjfine)
155 err = ops->adjfine(ops, tx->freq);
156 else
157 err = ops->adjfreq(ops, ppb);
158 ptp->dialed_frequency = tx->freq;
159 } else if (tx->modes == 0) {
160 tx->freq = ptp->dialed_frequency;
161 err = 0;
162 }
163
164 return err;
165 }
166
167 static struct posix_clock_operations ptp_clock_ops = {
168 .owner = THIS_MODULE,
169 .clock_adjtime = ptp_clock_adjtime,
170 .clock_gettime = ptp_clock_gettime,
171 .clock_getres = ptp_clock_getres,
172 .clock_settime = ptp_clock_settime,
173 .ioctl = ptp_ioctl,
174 .open = ptp_open,
175 .poll = ptp_poll,
176 .read = ptp_read,
177 };
178
ptp_clock_release(struct device * dev)179 static void ptp_clock_release(struct device *dev)
180 {
181 struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
182
183 ptp_cleanup_pin_groups(ptp);
184 mutex_destroy(&ptp->tsevq_mux);
185 mutex_destroy(&ptp->pincfg_mux);
186 ida_simple_remove(&ptp_clocks_map, ptp->index);
187 kfree(ptp);
188 }
189
ptp_aux_kworker(struct kthread_work * work)190 static void ptp_aux_kworker(struct kthread_work *work)
191 {
192 struct ptp_clock *ptp = container_of(work, struct ptp_clock,
193 aux_work.work);
194 struct ptp_clock_info *info = ptp->info;
195 long delay;
196
197 delay = info->do_aux_work(info);
198
199 if (delay >= 0)
200 kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
201 }
202
203 /* public interface */
204
ptp_clock_register(struct ptp_clock_info * info,struct device * parent)205 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
206 struct device *parent)
207 {
208 struct ptp_clock *ptp;
209 int err = 0, index, major = MAJOR(ptp_devt);
210
211 if (info->n_alarm > PTP_MAX_ALARMS)
212 return ERR_PTR(-EINVAL);
213
214 /* Initialize a clock structure. */
215 err = -ENOMEM;
216 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
217 if (ptp == NULL)
218 goto no_memory;
219
220 index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
221 if (index < 0) {
222 err = index;
223 goto no_slot;
224 }
225
226 ptp->clock.ops = ptp_clock_ops;
227 ptp->info = info;
228 ptp->devid = MKDEV(major, index);
229 ptp->index = index;
230 spin_lock_init(&ptp->tsevq.lock);
231 mutex_init(&ptp->tsevq_mux);
232 mutex_init(&ptp->pincfg_mux);
233 init_waitqueue_head(&ptp->tsev_wq);
234
235 if (ptp->info->do_aux_work) {
236 char *worker_name = kasprintf(GFP_KERNEL, "ptp%d", ptp->index);
237
238 kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
239 ptp->kworker = kthread_create_worker(0, worker_name ?
240 worker_name : info->name);
241 kfree(worker_name);
242 if (IS_ERR(ptp->kworker)) {
243 err = PTR_ERR(ptp->kworker);
244 pr_err("failed to create ptp aux_worker %d\n", err);
245 goto kworker_err;
246 }
247 }
248
249 err = ptp_populate_pin_groups(ptp);
250 if (err)
251 goto no_pin_groups;
252
253 /* Register a new PPS source. */
254 if (info->pps) {
255 struct pps_source_info pps;
256 memset(&pps, 0, sizeof(pps));
257 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
258 pps.mode = PTP_PPS_MODE;
259 pps.owner = info->owner;
260 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
261 if (!ptp->pps_source) {
262 err = -EINVAL;
263 pr_err("failed to register pps source\n");
264 goto no_pps;
265 }
266 }
267
268 /* Initialize a new device of our class in our clock structure. */
269 device_initialize(&ptp->dev);
270 ptp->dev.devt = ptp->devid;
271 ptp->dev.class = ptp_class;
272 ptp->dev.parent = parent;
273 ptp->dev.groups = ptp->pin_attr_groups;
274 ptp->dev.release = ptp_clock_release;
275 dev_set_drvdata(&ptp->dev, ptp);
276 dev_set_name(&ptp->dev, "ptp%d", ptp->index);
277
278 /* Create a posix clock and link it to the device. */
279 err = posix_clock_register(&ptp->clock, &ptp->dev);
280 if (err) {
281 pr_err("failed to create posix clock\n");
282 goto no_clock;
283 }
284
285 return ptp;
286
287 no_clock:
288 if (ptp->pps_source)
289 pps_unregister_source(ptp->pps_source);
290 no_pps:
291 ptp_cleanup_pin_groups(ptp);
292 no_pin_groups:
293 if (ptp->kworker)
294 kthread_destroy_worker(ptp->kworker);
295 kworker_err:
296 mutex_destroy(&ptp->tsevq_mux);
297 mutex_destroy(&ptp->pincfg_mux);
298 ida_simple_remove(&ptp_clocks_map, index);
299 no_slot:
300 kfree(ptp);
301 no_memory:
302 return ERR_PTR(err);
303 }
304 EXPORT_SYMBOL(ptp_clock_register);
305
ptp_clock_unregister(struct ptp_clock * ptp)306 int ptp_clock_unregister(struct ptp_clock *ptp)
307 {
308 ptp->defunct = 1;
309 wake_up_interruptible(&ptp->tsev_wq);
310
311 if (ptp->kworker) {
312 kthread_cancel_delayed_work_sync(&ptp->aux_work);
313 kthread_destroy_worker(ptp->kworker);
314 }
315
316 /* Release the clock's resources. */
317 if (ptp->pps_source)
318 pps_unregister_source(ptp->pps_source);
319
320 posix_clock_unregister(&ptp->clock);
321
322 return 0;
323 }
324 EXPORT_SYMBOL(ptp_clock_unregister);
325
ptp_clock_event(struct ptp_clock * ptp,struct ptp_clock_event * event)326 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
327 {
328 struct pps_event_time evt;
329
330 switch (event->type) {
331
332 case PTP_CLOCK_ALARM:
333 break;
334
335 case PTP_CLOCK_EXTTS:
336 enqueue_external_timestamp(&ptp->tsevq, event);
337 wake_up_interruptible(&ptp->tsev_wq);
338 break;
339
340 case PTP_CLOCK_PPS:
341 pps_get_ts(&evt);
342 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
343 break;
344
345 case PTP_CLOCK_PPSUSR:
346 pps_event(ptp->pps_source, &event->pps_times,
347 PTP_PPS_EVENT, NULL);
348 break;
349 }
350 }
351 EXPORT_SYMBOL(ptp_clock_event);
352
ptp_clock_index(struct ptp_clock * ptp)353 int ptp_clock_index(struct ptp_clock *ptp)
354 {
355 return ptp->index;
356 }
357 EXPORT_SYMBOL(ptp_clock_index);
358
ptp_find_pin(struct ptp_clock * ptp,enum ptp_pin_function func,unsigned int chan)359 int ptp_find_pin(struct ptp_clock *ptp,
360 enum ptp_pin_function func, unsigned int chan)
361 {
362 struct ptp_pin_desc *pin = NULL;
363 int i;
364
365 mutex_lock(&ptp->pincfg_mux);
366 for (i = 0; i < ptp->info->n_pins; i++) {
367 if (ptp->info->pin_config[i].func == func &&
368 ptp->info->pin_config[i].chan == chan) {
369 pin = &ptp->info->pin_config[i];
370 break;
371 }
372 }
373 mutex_unlock(&ptp->pincfg_mux);
374
375 return pin ? i : -1;
376 }
377 EXPORT_SYMBOL(ptp_find_pin);
378
ptp_schedule_worker(struct ptp_clock * ptp,unsigned long delay)379 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
380 {
381 return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
382 }
383 EXPORT_SYMBOL(ptp_schedule_worker);
384
385 /* module operations */
386
ptp_exit(void)387 static void __exit ptp_exit(void)
388 {
389 class_destroy(ptp_class);
390 unregister_chrdev_region(ptp_devt, MINORMASK + 1);
391 ida_destroy(&ptp_clocks_map);
392 }
393
ptp_init(void)394 static int __init ptp_init(void)
395 {
396 int err;
397
398 ptp_class = class_create(THIS_MODULE, "ptp");
399 if (IS_ERR(ptp_class)) {
400 pr_err("ptp: failed to allocate class\n");
401 return PTR_ERR(ptp_class);
402 }
403
404 err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
405 if (err < 0) {
406 pr_err("ptp: failed to allocate device region\n");
407 goto no_region;
408 }
409
410 ptp_class->dev_groups = ptp_groups;
411 pr_info("PTP clock support registered\n");
412 return 0;
413
414 no_region:
415 class_destroy(ptp_class);
416 return err;
417 }
418
419 subsys_initcall(ptp_init);
420 module_exit(ptp_exit);
421
422 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
423 MODULE_DESCRIPTION("PTP clocks support");
424 MODULE_LICENSE("GPL");
425