1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * PTP 1588 clock support
4 *
5 * Copyright (C) 2010 OMICRON electronics GmbH
6 */
7 #include <linux/idr.h>
8 #include <linux/device.h>
9 #include <linux/err.h>
10 #include <linux/init.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/posix-clock.h>
14 #include <linux/pps_kernel.h>
15 #include <linux/slab.h>
16 #include <linux/syscalls.h>
17 #include <linux/uaccess.h>
18 #include <uapi/linux/sched/types.h>
19
20 #include "ptp_private.h"
21
22 #define PTP_MAX_ALARMS 4
23 #define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT)
24 #define PTP_PPS_EVENT PPS_CAPTUREASSERT
25 #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)
26
27 /* private globals */
28
29 static dev_t ptp_devt;
30 static struct class *ptp_class;
31
32 static DEFINE_IDA(ptp_clocks_map);
33
34 /* time stamp event queue operations */
35
queue_free(struct timestamp_event_queue * q)36 static inline int queue_free(struct timestamp_event_queue *q)
37 {
38 return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
39 }
40
enqueue_external_timestamp(struct timestamp_event_queue * queue,struct ptp_clock_event * src)41 static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
42 struct ptp_clock_event *src)
43 {
44 struct ptp_extts_event *dst;
45 unsigned long flags;
46 s64 seconds;
47 u32 remainder;
48
49 seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
50
51 spin_lock_irqsave(&queue->lock, flags);
52
53 dst = &queue->buf[queue->tail];
54 dst->index = src->index;
55 dst->t.sec = seconds;
56 dst->t.nsec = remainder;
57
58 if (!queue_free(queue))
59 queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
60
61 queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;
62
63 spin_unlock_irqrestore(&queue->lock, flags);
64 }
65
scaled_ppm_to_ppb(long ppm)66 long scaled_ppm_to_ppb(long ppm)
67 {
68 /*
69 * The 'freq' field in the 'struct timex' is in parts per
70 * million, but with a 16 bit binary fractional field.
71 *
72 * We want to calculate
73 *
74 * ppb = scaled_ppm * 1000 / 2^16
75 *
76 * which simplifies to
77 *
78 * ppb = scaled_ppm * 125 / 2^13
79 */
80 s64 ppb = 1 + ppm;
81 ppb *= 125;
82 ppb >>= 13;
83 return (long) ppb;
84 }
85 EXPORT_SYMBOL(scaled_ppm_to_ppb);
86
87 /* posix clock implementation */
88
ptp_clock_getres(struct posix_clock * pc,struct timespec64 * tp)89 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
90 {
91 tp->tv_sec = 0;
92 tp->tv_nsec = 1;
93 return 0;
94 }
95
ptp_clock_settime(struct posix_clock * pc,const struct timespec64 * tp)96 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
97 {
98 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
99
100 return ptp->info->settime64(ptp->info, tp);
101 }
102
ptp_clock_gettime(struct posix_clock * pc,struct timespec64 * tp)103 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
104 {
105 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
106 int err;
107
108 if (ptp->info->gettimex64)
109 err = ptp->info->gettimex64(ptp->info, tp, NULL);
110 else
111 err = ptp->info->gettime64(ptp->info, tp);
112 return err;
113 }
114
ptp_clock_adjtime(struct posix_clock * pc,struct __kernel_timex * tx)115 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
116 {
117 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
118 struct ptp_clock_info *ops;
119 int err = -EOPNOTSUPP;
120
121 ops = ptp->info;
122
123 if (tx->modes & ADJ_SETOFFSET) {
124 struct timespec64 ts;
125 ktime_t kt;
126 s64 delta;
127
128 ts.tv_sec = tx->time.tv_sec;
129 ts.tv_nsec = tx->time.tv_usec;
130
131 if (!(tx->modes & ADJ_NANO))
132 ts.tv_nsec *= 1000;
133
134 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
135 return -EINVAL;
136
137 kt = timespec64_to_ktime(ts);
138 delta = ktime_to_ns(kt);
139 err = ops->adjtime(ops, delta);
140 } else if (tx->modes & ADJ_FREQUENCY) {
141 long ppb = scaled_ppm_to_ppb(tx->freq);
142 if (ppb > ops->max_adj || ppb < -ops->max_adj)
143 return -ERANGE;
144 if (ops->adjfine)
145 err = ops->adjfine(ops, tx->freq);
146 else
147 err = ops->adjfreq(ops, ppb);
148 ptp->dialed_frequency = tx->freq;
149 } else if (tx->modes & ADJ_OFFSET) {
150 if (ops->adjphase) {
151 s32 offset = tx->offset;
152
153 if (!(tx->modes & ADJ_NANO))
154 offset *= NSEC_PER_USEC;
155
156 err = ops->adjphase(ops, offset);
157 }
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 kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
236 ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
237 if (IS_ERR(ptp->kworker)) {
238 err = PTR_ERR(ptp->kworker);
239 pr_err("failed to create ptp aux_worker %d\n", err);
240 goto kworker_err;
241 }
242 }
243
244 err = ptp_populate_pin_groups(ptp);
245 if (err)
246 goto no_pin_groups;
247
248 /* Register a new PPS source. */
249 if (info->pps) {
250 struct pps_source_info pps;
251 memset(&pps, 0, sizeof(pps));
252 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
253 pps.mode = PTP_PPS_MODE;
254 pps.owner = info->owner;
255 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
256 if (IS_ERR(ptp->pps_source)) {
257 err = PTR_ERR(ptp->pps_source);
258 pr_err("failed to register pps source\n");
259 goto no_pps;
260 }
261 }
262
263 /* Initialize a new device of our class in our clock structure. */
264 device_initialize(&ptp->dev);
265 ptp->dev.devt = ptp->devid;
266 ptp->dev.class = ptp_class;
267 ptp->dev.parent = parent;
268 ptp->dev.groups = ptp->pin_attr_groups;
269 ptp->dev.release = ptp_clock_release;
270 dev_set_drvdata(&ptp->dev, ptp);
271 dev_set_name(&ptp->dev, "ptp%d", ptp->index);
272
273 /* Create a posix clock and link it to the device. */
274 err = posix_clock_register(&ptp->clock, &ptp->dev);
275 if (err) {
276 pr_err("failed to create posix clock\n");
277 goto no_clock;
278 }
279
280 return ptp;
281
282 no_clock:
283 if (ptp->pps_source)
284 pps_unregister_source(ptp->pps_source);
285 no_pps:
286 ptp_cleanup_pin_groups(ptp);
287 no_pin_groups:
288 if (ptp->kworker)
289 kthread_destroy_worker(ptp->kworker);
290 kworker_err:
291 mutex_destroy(&ptp->tsevq_mux);
292 mutex_destroy(&ptp->pincfg_mux);
293 ida_simple_remove(&ptp_clocks_map, index);
294 no_slot:
295 kfree(ptp);
296 no_memory:
297 return ERR_PTR(err);
298 }
299 EXPORT_SYMBOL(ptp_clock_register);
300
ptp_clock_unregister(struct ptp_clock * ptp)301 int ptp_clock_unregister(struct ptp_clock *ptp)
302 {
303 ptp->defunct = 1;
304 wake_up_interruptible(&ptp->tsev_wq);
305
306 if (ptp->kworker) {
307 kthread_cancel_delayed_work_sync(&ptp->aux_work);
308 kthread_destroy_worker(ptp->kworker);
309 }
310
311 /* Release the clock's resources. */
312 if (ptp->pps_source)
313 pps_unregister_source(ptp->pps_source);
314
315 posix_clock_unregister(&ptp->clock);
316
317 return 0;
318 }
319 EXPORT_SYMBOL(ptp_clock_unregister);
320
ptp_clock_event(struct ptp_clock * ptp,struct ptp_clock_event * event)321 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
322 {
323 struct pps_event_time evt;
324
325 switch (event->type) {
326
327 case PTP_CLOCK_ALARM:
328 break;
329
330 case PTP_CLOCK_EXTTS:
331 enqueue_external_timestamp(&ptp->tsevq, event);
332 wake_up_interruptible(&ptp->tsev_wq);
333 break;
334
335 case PTP_CLOCK_PPS:
336 pps_get_ts(&evt);
337 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
338 break;
339
340 case PTP_CLOCK_PPSUSR:
341 pps_event(ptp->pps_source, &event->pps_times,
342 PTP_PPS_EVENT, NULL);
343 break;
344 }
345 }
346 EXPORT_SYMBOL(ptp_clock_event);
347
ptp_clock_index(struct ptp_clock * ptp)348 int ptp_clock_index(struct ptp_clock *ptp)
349 {
350 return ptp->index;
351 }
352 EXPORT_SYMBOL(ptp_clock_index);
353
ptp_find_pin(struct ptp_clock * ptp,enum ptp_pin_function func,unsigned int chan)354 int ptp_find_pin(struct ptp_clock *ptp,
355 enum ptp_pin_function func, unsigned int chan)
356 {
357 struct ptp_pin_desc *pin = NULL;
358 int i;
359
360 for (i = 0; i < ptp->info->n_pins; i++) {
361 if (ptp->info->pin_config[i].func == func &&
362 ptp->info->pin_config[i].chan == chan) {
363 pin = &ptp->info->pin_config[i];
364 break;
365 }
366 }
367
368 return pin ? i : -1;
369 }
370 EXPORT_SYMBOL(ptp_find_pin);
371
ptp_find_pin_unlocked(struct ptp_clock * ptp,enum ptp_pin_function func,unsigned int chan)372 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
373 enum ptp_pin_function func, unsigned int chan)
374 {
375 int result;
376
377 mutex_lock(&ptp->pincfg_mux);
378
379 result = ptp_find_pin(ptp, func, chan);
380
381 mutex_unlock(&ptp->pincfg_mux);
382
383 return result;
384 }
385 EXPORT_SYMBOL(ptp_find_pin_unlocked);
386
ptp_schedule_worker(struct ptp_clock * ptp,unsigned long delay)387 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
388 {
389 return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
390 }
391 EXPORT_SYMBOL(ptp_schedule_worker);
392
ptp_cancel_worker_sync(struct ptp_clock * ptp)393 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
394 {
395 kthread_cancel_delayed_work_sync(&ptp->aux_work);
396 }
397 EXPORT_SYMBOL(ptp_cancel_worker_sync);
398
399 /* module operations */
400
ptp_exit(void)401 static void __exit ptp_exit(void)
402 {
403 class_destroy(ptp_class);
404 unregister_chrdev_region(ptp_devt, MINORMASK + 1);
405 ida_destroy(&ptp_clocks_map);
406 }
407
ptp_init(void)408 static int __init ptp_init(void)
409 {
410 int err;
411
412 ptp_class = class_create(THIS_MODULE, "ptp");
413 if (IS_ERR(ptp_class)) {
414 pr_err("ptp: failed to allocate class\n");
415 return PTR_ERR(ptp_class);
416 }
417
418 err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
419 if (err < 0) {
420 pr_err("ptp: failed to allocate device region\n");
421 goto no_region;
422 }
423
424 ptp_class->dev_groups = ptp_groups;
425 pr_info("PTP clock support registered\n");
426 return 0;
427
428 no_region:
429 class_destroy(ptp_class);
430 return err;
431 }
432
433 subsys_initcall(ptp_init);
434 module_exit(ptp_exit);
435
436 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
437 MODULE_DESCRIPTION("PTP clocks support");
438 MODULE_LICENSE("GPL");
439