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 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
ptp_clock_getres(struct posix_clock * pc,struct timespec64 * tp)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
ptp_clock_settime(struct posix_clock * pc,const struct timespec64 * tp)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
ptp_clock_gettime(struct posix_clock * pc,struct timespec64 * tp)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
ptp_clock_adjtime(struct posix_clock * pc,struct timex * tx)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
ptp_clock_release(struct device * dev)178 static void ptp_clock_release(struct device *dev)
179 {
180 struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
181
182 ptp_cleanup_pin_groups(ptp);
183 mutex_destroy(&ptp->tsevq_mux);
184 mutex_destroy(&ptp->pincfg_mux);
185 ida_simple_remove(&ptp_clocks_map, ptp->index);
186 kfree(ptp);
187 }
188
ptp_aux_kworker(struct kthread_work * work)189 static void ptp_aux_kworker(struct kthread_work *work)
190 {
191 struct ptp_clock *ptp = container_of(work, struct ptp_clock,
192 aux_work.work);
193 struct ptp_clock_info *info = ptp->info;
194 long delay;
195
196 delay = info->do_aux_work(info);
197
198 if (delay >= 0)
199 kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
200 }
201
202 /* public interface */
203
ptp_clock_register(struct ptp_clock_info * info,struct device * parent)204 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
205 struct device *parent)
206 {
207 struct ptp_clock *ptp;
208 int err = 0, index, major = MAJOR(ptp_devt);
209
210 if (info->n_alarm > PTP_MAX_ALARMS)
211 return ERR_PTR(-EINVAL);
212
213 /* Initialize a clock structure. */
214 err = -ENOMEM;
215 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
216 if (ptp == NULL)
217 goto no_memory;
218
219 index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
220 if (index < 0) {
221 err = index;
222 goto no_slot;
223 }
224
225 ptp->clock.ops = ptp_clock_ops;
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 /* Register a new PPS source. */
253 if (info->pps) {
254 struct pps_source_info pps;
255 memset(&pps, 0, sizeof(pps));
256 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
257 pps.mode = PTP_PPS_MODE;
258 pps.owner = info->owner;
259 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
260 if (!ptp->pps_source) {
261 err = -EINVAL;
262 pr_err("failed to register pps source\n");
263 goto no_pps;
264 }
265 }
266
267 /* Initialize a new device of our class in our clock structure. */
268 device_initialize(&ptp->dev);
269 ptp->dev.devt = ptp->devid;
270 ptp->dev.class = ptp_class;
271 ptp->dev.parent = parent;
272 ptp->dev.groups = ptp->pin_attr_groups;
273 ptp->dev.release = ptp_clock_release;
274 dev_set_drvdata(&ptp->dev, ptp);
275 dev_set_name(&ptp->dev, "ptp%d", ptp->index);
276
277 /* Create a posix clock and link it to the device. */
278 err = posix_clock_register(&ptp->clock, &ptp->dev);
279 if (err) {
280 pr_err("failed to create posix clock\n");
281 goto no_clock;
282 }
283
284 return ptp;
285
286 no_clock:
287 if (ptp->pps_source)
288 pps_unregister_source(ptp->pps_source);
289 no_pps:
290 ptp_cleanup_pin_groups(ptp);
291 no_pin_groups:
292 if (ptp->kworker)
293 kthread_destroy_worker(ptp->kworker);
294 kworker_err:
295 mutex_destroy(&ptp->tsevq_mux);
296 mutex_destroy(&ptp->pincfg_mux);
297 ida_simple_remove(&ptp_clocks_map, index);
298 no_slot:
299 kfree(ptp);
300 no_memory:
301 return ERR_PTR(err);
302 }
303 EXPORT_SYMBOL(ptp_clock_register);
304
ptp_clock_unregister(struct ptp_clock * ptp)305 int ptp_clock_unregister(struct ptp_clock *ptp)
306 {
307 ptp->defunct = 1;
308 wake_up_interruptible(&ptp->tsev_wq);
309
310 if (ptp->kworker) {
311 kthread_cancel_delayed_work_sync(&ptp->aux_work);
312 kthread_destroy_worker(ptp->kworker);
313 }
314
315 /* Release the clock's resources. */
316 if (ptp->pps_source)
317 pps_unregister_source(ptp->pps_source);
318
319 posix_clock_unregister(&ptp->clock);
320
321 return 0;
322 }
323 EXPORT_SYMBOL(ptp_clock_unregister);
324
ptp_clock_event(struct ptp_clock * ptp,struct ptp_clock_event * event)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
ptp_clock_index(struct ptp_clock * ptp)352 int ptp_clock_index(struct ptp_clock *ptp)
353 {
354 return ptp->index;
355 }
356 EXPORT_SYMBOL(ptp_clock_index);
357
ptp_find_pin(struct ptp_clock * ptp,enum ptp_pin_function func,unsigned int chan)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
ptp_schedule_worker(struct ptp_clock * ptp,unsigned long delay)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
ptp_exit(void)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
ptp_init(void)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