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_enable(struct ptp_clock_info * ptp,struct ptp_clock_request * request,int on)190 static int ptp_enable(struct ptp_clock_info *ptp, struct ptp_clock_request *request, int on)
191 {
192 return -EOPNOTSUPP;
193 }
194
ptp_aux_kworker(struct kthread_work * work)195 static void ptp_aux_kworker(struct kthread_work *work)
196 {
197 struct ptp_clock *ptp = container_of(work, struct ptp_clock,
198 aux_work.work);
199 struct ptp_clock_info *info = ptp->info;
200 long delay;
201
202 delay = info->do_aux_work(info);
203
204 if (delay >= 0)
205 kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
206 }
207
208 /* public interface */
209
ptp_clock_register(struct ptp_clock_info * info,struct device * parent)210 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
211 struct device *parent)
212 {
213 struct ptp_clock *ptp;
214 int err = 0, index, major = MAJOR(ptp_devt);
215
216 if (info->n_alarm > PTP_MAX_ALARMS)
217 return ERR_PTR(-EINVAL);
218
219 /* Initialize a clock structure. */
220 err = -ENOMEM;
221 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
222 if (ptp == NULL)
223 goto no_memory;
224
225 index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
226 if (index < 0) {
227 err = index;
228 goto no_slot;
229 }
230
231 ptp->clock.ops = ptp_clock_ops;
232 ptp->info = info;
233 ptp->devid = MKDEV(major, index);
234 ptp->index = index;
235 spin_lock_init(&ptp->tsevq.lock);
236 mutex_init(&ptp->tsevq_mux);
237 mutex_init(&ptp->pincfg_mux);
238 init_waitqueue_head(&ptp->tsev_wq);
239
240 if (!ptp->info->enable)
241 ptp->info->enable = ptp_enable;
242
243 if (ptp->info->do_aux_work) {
244 kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
245 ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
246 if (IS_ERR(ptp->kworker)) {
247 err = PTR_ERR(ptp->kworker);
248 pr_err("failed to create ptp aux_worker %d\n", err);
249 goto kworker_err;
250 }
251 }
252
253 err = ptp_populate_pin_groups(ptp);
254 if (err)
255 goto no_pin_groups;
256
257 /* Register a new PPS source. */
258 if (info->pps) {
259 struct pps_source_info pps;
260 memset(&pps, 0, sizeof(pps));
261 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
262 pps.mode = PTP_PPS_MODE;
263 pps.owner = info->owner;
264 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
265 if (IS_ERR(ptp->pps_source)) {
266 err = PTR_ERR(ptp->pps_source);
267 pr_err("failed to register pps source\n");
268 goto no_pps;
269 }
270 }
271
272 /* Initialize a new device of our class in our clock structure. */
273 device_initialize(&ptp->dev);
274 ptp->dev.devt = ptp->devid;
275 ptp->dev.class = ptp_class;
276 ptp->dev.parent = parent;
277 ptp->dev.groups = ptp->pin_attr_groups;
278 ptp->dev.release = ptp_clock_release;
279 dev_set_drvdata(&ptp->dev, ptp);
280 dev_set_name(&ptp->dev, "ptp%d", ptp->index);
281
282 /* Create a posix clock and link it to the device. */
283 err = posix_clock_register(&ptp->clock, &ptp->dev);
284 if (err) {
285 pr_err("failed to create posix clock\n");
286 goto no_clock;
287 }
288
289 return ptp;
290
291 no_clock:
292 if (ptp->pps_source)
293 pps_unregister_source(ptp->pps_source);
294 no_pps:
295 ptp_cleanup_pin_groups(ptp);
296 no_pin_groups:
297 if (ptp->kworker)
298 kthread_destroy_worker(ptp->kworker);
299 kworker_err:
300 mutex_destroy(&ptp->tsevq_mux);
301 mutex_destroy(&ptp->pincfg_mux);
302 ida_simple_remove(&ptp_clocks_map, index);
303 no_slot:
304 kfree(ptp);
305 no_memory:
306 return ERR_PTR(err);
307 }
308 EXPORT_SYMBOL(ptp_clock_register);
309
ptp_clock_unregister(struct ptp_clock * ptp)310 int ptp_clock_unregister(struct ptp_clock *ptp)
311 {
312 ptp->defunct = 1;
313 wake_up_interruptible(&ptp->tsev_wq);
314
315 if (ptp->kworker) {
316 kthread_cancel_delayed_work_sync(&ptp->aux_work);
317 kthread_destroy_worker(ptp->kworker);
318 }
319
320 /* Release the clock's resources. */
321 if (ptp->pps_source)
322 pps_unregister_source(ptp->pps_source);
323
324 posix_clock_unregister(&ptp->clock);
325
326 return 0;
327 }
328 EXPORT_SYMBOL(ptp_clock_unregister);
329
ptp_clock_event(struct ptp_clock * ptp,struct ptp_clock_event * event)330 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
331 {
332 struct pps_event_time evt;
333
334 switch (event->type) {
335
336 case PTP_CLOCK_ALARM:
337 break;
338
339 case PTP_CLOCK_EXTTS:
340 enqueue_external_timestamp(&ptp->tsevq, event);
341 wake_up_interruptible(&ptp->tsev_wq);
342 break;
343
344 case PTP_CLOCK_PPS:
345 pps_get_ts(&evt);
346 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
347 break;
348
349 case PTP_CLOCK_PPSUSR:
350 pps_event(ptp->pps_source, &event->pps_times,
351 PTP_PPS_EVENT, NULL);
352 break;
353 }
354 }
355 EXPORT_SYMBOL(ptp_clock_event);
356
ptp_clock_index(struct ptp_clock * ptp)357 int ptp_clock_index(struct ptp_clock *ptp)
358 {
359 return ptp->index;
360 }
361 EXPORT_SYMBOL(ptp_clock_index);
362
ptp_find_pin(struct ptp_clock * ptp,enum ptp_pin_function func,unsigned int chan)363 int ptp_find_pin(struct ptp_clock *ptp,
364 enum ptp_pin_function func, unsigned int chan)
365 {
366 struct ptp_pin_desc *pin = NULL;
367 int i;
368
369 for (i = 0; i < ptp->info->n_pins; i++) {
370 if (ptp->info->pin_config[i].func == func &&
371 ptp->info->pin_config[i].chan == chan) {
372 pin = &ptp->info->pin_config[i];
373 break;
374 }
375 }
376
377 return pin ? i : -1;
378 }
379 EXPORT_SYMBOL(ptp_find_pin);
380
ptp_find_pin_unlocked(struct ptp_clock * ptp,enum ptp_pin_function func,unsigned int chan)381 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
382 enum ptp_pin_function func, unsigned int chan)
383 {
384 int result;
385
386 mutex_lock(&ptp->pincfg_mux);
387
388 result = ptp_find_pin(ptp, func, chan);
389
390 mutex_unlock(&ptp->pincfg_mux);
391
392 return result;
393 }
394 EXPORT_SYMBOL(ptp_find_pin_unlocked);
395
ptp_schedule_worker(struct ptp_clock * ptp,unsigned long delay)396 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
397 {
398 return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
399 }
400 EXPORT_SYMBOL(ptp_schedule_worker);
401
ptp_cancel_worker_sync(struct ptp_clock * ptp)402 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
403 {
404 kthread_cancel_delayed_work_sync(&ptp->aux_work);
405 }
406 EXPORT_SYMBOL(ptp_cancel_worker_sync);
407
408 /* module operations */
409
ptp_exit(void)410 static void __exit ptp_exit(void)
411 {
412 class_destroy(ptp_class);
413 unregister_chrdev_region(ptp_devt, MINORMASK + 1);
414 ida_destroy(&ptp_clocks_map);
415 }
416
ptp_init(void)417 static int __init ptp_init(void)
418 {
419 int err;
420
421 ptp_class = class_create(THIS_MODULE, "ptp");
422 if (IS_ERR(ptp_class)) {
423 pr_err("ptp: failed to allocate class\n");
424 return PTR_ERR(ptp_class);
425 }
426
427 err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
428 if (err < 0) {
429 pr_err("ptp: failed to allocate device region\n");
430 goto no_region;
431 }
432
433 ptp_class->dev_groups = ptp_groups;
434 pr_info("PTP clock support registered\n");
435 return 0;
436
437 no_region:
438 class_destroy(ptp_class);
439 return err;
440 }
441
442 subsys_initcall(ptp_init);
443 module_exit(ptp_exit);
444
445 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
446 MODULE_DESCRIPTION("PTP clocks support");
447 MODULE_LICENSE("GPL");
448