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 /* Both WRITE_ONCE() are paired with READ_ONCE() in queue_cnt() */
59 if (!queue_free(queue))
60 WRITE_ONCE(queue->head, (queue->head + 1) % PTP_MAX_TIMESTAMPS);
61
62 WRITE_ONCE(queue->tail, (queue->tail + 1) % PTP_MAX_TIMESTAMPS);
63
64 spin_unlock_irqrestore(&queue->lock, flags);
65 }
66
scaled_ppm_to_ppb(long ppm)67 long scaled_ppm_to_ppb(long ppm)
68 {
69 /*
70 * The 'freq' field in the 'struct timex' is in parts per
71 * million, but with a 16 bit binary fractional field.
72 *
73 * We want to calculate
74 *
75 * ppb = scaled_ppm * 1000 / 2^16
76 *
77 * which simplifies to
78 *
79 * ppb = scaled_ppm * 125 / 2^13
80 */
81 s64 ppb = 1 + ppm;
82 ppb *= 125;
83 ppb >>= 13;
84 return (long) ppb;
85 }
86 EXPORT_SYMBOL(scaled_ppm_to_ppb);
87
88 /* posix clock implementation */
89
ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)90 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
91 {
92 tp->tv_sec = 0;
93 tp->tv_nsec = 1;
94 return 0;
95 }
96
ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)97 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
98 {
99 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
100
101 return ptp->info->settime64(ptp->info, tp);
102 }
103
ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)104 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
105 {
106 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
107 int err;
108
109 if (ptp->info->gettimex64)
110 err = ptp->info->gettimex64(ptp->info, tp, NULL);
111 else
112 err = ptp->info->gettime64(ptp->info, tp);
113 return err;
114 }
115
ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)116 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
117 {
118 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
119 struct ptp_clock_info *ops;
120 int err = -EOPNOTSUPP;
121
122 ops = ptp->info;
123
124 if (tx->modes & ADJ_SETOFFSET) {
125 struct timespec64 ts;
126 ktime_t kt;
127 s64 delta;
128
129 ts.tv_sec = tx->time.tv_sec;
130 ts.tv_nsec = tx->time.tv_usec;
131
132 if (!(tx->modes & ADJ_NANO))
133 ts.tv_nsec *= 1000;
134
135 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
136 return -EINVAL;
137
138 kt = timespec64_to_ktime(ts);
139 delta = ktime_to_ns(kt);
140 err = ops->adjtime(ops, delta);
141 } else if (tx->modes & ADJ_FREQUENCY) {
142 long ppb = scaled_ppm_to_ppb(tx->freq);
143 if (ppb > ops->max_adj || ppb < -ops->max_adj)
144 return -ERANGE;
145 if (ops->adjfine)
146 err = ops->adjfine(ops, tx->freq);
147 else
148 err = ops->adjfreq(ops, ppb);
149 ptp->dialed_frequency = tx->freq;
150 } else if (tx->modes & ADJ_OFFSET) {
151 if (ops->adjphase) {
152 s32 offset = tx->offset;
153
154 if (!(tx->modes & ADJ_NANO))
155 offset *= NSEC_PER_USEC;
156
157 err = ops->adjphase(ops, offset);
158 }
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 kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
237 ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
238 if (IS_ERR(ptp->kworker)) {
239 err = PTR_ERR(ptp->kworker);
240 pr_err("failed to create ptp aux_worker %d\n", err);
241 goto kworker_err;
242 }
243 }
244
245 err = ptp_populate_pin_groups(ptp);
246 if (err)
247 goto no_pin_groups;
248
249 /* Register a new PPS source. */
250 if (info->pps) {
251 struct pps_source_info pps;
252 memset(&pps, 0, sizeof(pps));
253 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
254 pps.mode = PTP_PPS_MODE;
255 pps.owner = info->owner;
256 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
257 if (IS_ERR(ptp->pps_source)) {
258 err = PTR_ERR(ptp->pps_source);
259 pr_err("failed to register pps source\n");
260 goto no_pps;
261 }
262 }
263
264 /* Initialize a new device of our class in our clock structure. */
265 device_initialize(&ptp->dev);
266 ptp->dev.devt = ptp->devid;
267 ptp->dev.class = ptp_class;
268 ptp->dev.parent = parent;
269 ptp->dev.groups = ptp->pin_attr_groups;
270 ptp->dev.release = ptp_clock_release;
271 dev_set_drvdata(&ptp->dev, ptp);
272 dev_set_name(&ptp->dev, "ptp%d", ptp->index);
273
274 /* Create a posix clock and link it to the device. */
275 err = posix_clock_register(&ptp->clock, &ptp->dev);
276 if (err) {
277 pr_err("failed to create posix clock\n");
278 goto no_clock;
279 }
280
281 return ptp;
282
283 no_clock:
284 if (ptp->pps_source)
285 pps_unregister_source(ptp->pps_source);
286 no_pps:
287 ptp_cleanup_pin_groups(ptp);
288 no_pin_groups:
289 if (ptp->kworker)
290 kthread_destroy_worker(ptp->kworker);
291 kworker_err:
292 mutex_destroy(&ptp->tsevq_mux);
293 mutex_destroy(&ptp->pincfg_mux);
294 ida_simple_remove(&ptp_clocks_map, index);
295 no_slot:
296 kfree(ptp);
297 no_memory:
298 return ERR_PTR(err);
299 }
300 EXPORT_SYMBOL(ptp_clock_register);
301
ptp_clock_unregister(struct ptp_clock *ptp)302 int ptp_clock_unregister(struct ptp_clock *ptp)
303 {
304 ptp->defunct = 1;
305 wake_up_interruptible(&ptp->tsev_wq);
306
307 if (ptp->kworker) {
308 kthread_cancel_delayed_work_sync(&ptp->aux_work);
309 kthread_destroy_worker(ptp->kworker);
310 }
311
312 /* Release the clock's resources. */
313 if (ptp->pps_source)
314 pps_unregister_source(ptp->pps_source);
315
316 posix_clock_unregister(&ptp->clock);
317
318 return 0;
319 }
320 EXPORT_SYMBOL(ptp_clock_unregister);
321
ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)322 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
323 {
324 struct pps_event_time evt;
325
326 switch (event->type) {
327
328 case PTP_CLOCK_ALARM:
329 break;
330
331 case PTP_CLOCK_EXTTS:
332 enqueue_external_timestamp(&ptp->tsevq, event);
333 wake_up_interruptible(&ptp->tsev_wq);
334 break;
335
336 case PTP_CLOCK_PPS:
337 pps_get_ts(&evt);
338 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
339 break;
340
341 case PTP_CLOCK_PPSUSR:
342 pps_event(ptp->pps_source, &event->pps_times,
343 PTP_PPS_EVENT, NULL);
344 break;
345 }
346 }
347 EXPORT_SYMBOL(ptp_clock_event);
348
ptp_clock_index(struct ptp_clock *ptp)349 int ptp_clock_index(struct ptp_clock *ptp)
350 {
351 return ptp->index;
352 }
353 EXPORT_SYMBOL(ptp_clock_index);
354
ptp_find_pin(struct ptp_clock *ptp, enum ptp_pin_function func, unsigned int chan)355 int ptp_find_pin(struct ptp_clock *ptp,
356 enum ptp_pin_function func, unsigned int chan)
357 {
358 struct ptp_pin_desc *pin = NULL;
359 int i;
360
361 for (i = 0; i < ptp->info->n_pins; i++) {
362 if (ptp->info->pin_config[i].func == func &&
363 ptp->info->pin_config[i].chan == chan) {
364 pin = &ptp->info->pin_config[i];
365 break;
366 }
367 }
368
369 return pin ? i : -1;
370 }
371 EXPORT_SYMBOL(ptp_find_pin);
372
ptp_find_pin_unlocked(struct ptp_clock *ptp, enum ptp_pin_function func, unsigned int chan)373 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
374 enum ptp_pin_function func, unsigned int chan)
375 {
376 int result;
377
378 mutex_lock(&ptp->pincfg_mux);
379
380 result = ptp_find_pin(ptp, func, chan);
381
382 mutex_unlock(&ptp->pincfg_mux);
383
384 return result;
385 }
386 EXPORT_SYMBOL(ptp_find_pin_unlocked);
387
ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)388 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
389 {
390 return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
391 }
392 EXPORT_SYMBOL(ptp_schedule_worker);
393
ptp_cancel_worker_sync(struct ptp_clock *ptp)394 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
395 {
396 kthread_cancel_delayed_work_sync(&ptp->aux_work);
397 }
398 EXPORT_SYMBOL(ptp_cancel_worker_sync);
399
400 /* module operations */
401
ptp_exit(void)402 static void __exit ptp_exit(void)
403 {
404 class_destroy(ptp_class);
405 unregister_chrdev_region(ptp_devt, MINORMASK + 1);
406 ida_destroy(&ptp_clocks_map);
407 }
408
ptp_init(void)409 static int __init ptp_init(void)
410 {
411 int err;
412
413 ptp_class = class_create(THIS_MODULE, "ptp");
414 if (IS_ERR(ptp_class)) {
415 pr_err("ptp: failed to allocate class\n");
416 return PTR_ERR(ptp_class);
417 }
418
419 err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
420 if (err < 0) {
421 pr_err("ptp: failed to allocate device region\n");
422 goto no_region;
423 }
424
425 ptp_class->dev_groups = ptp_groups;
426 pr_info("PTP clock support registered\n");
427 return 0;
428
429 no_region:
430 class_destroy(ptp_class);
431 return err;
432 }
433
434 subsys_initcall(ptp_init);
435 module_exit(ptp_exit);
436
437 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
438 MODULE_DESCRIPTION("PTP clocks support");
439 MODULE_LICENSE("GPL");
440