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
29static dev_t ptp_devt;
30static struct class *ptp_class;
31
32static DEFINE_IDA(ptp_clocks_map);
33
34/* time stamp event queue operations */
35
36static inline int queue_free(struct timestamp_event_queue *q)
37{
38	return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
39}
40
41static 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
67long 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}
86EXPORT_SYMBOL(scaled_ppm_to_ppb);
87
88/* posix clock implementation */
89
90static 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
97static 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
104static 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
116static 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
167static 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
179static 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
190static 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
205struct 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
283no_clock:
284	if (ptp->pps_source)
285		pps_unregister_source(ptp->pps_source);
286no_pps:
287	ptp_cleanup_pin_groups(ptp);
288no_pin_groups:
289	if (ptp->kworker)
290		kthread_destroy_worker(ptp->kworker);
291kworker_err:
292	mutex_destroy(&ptp->tsevq_mux);
293	mutex_destroy(&ptp->pincfg_mux);
294	ida_simple_remove(&ptp_clocks_map, index);
295no_slot:
296	kfree(ptp);
297no_memory:
298	return ERR_PTR(err);
299}
300EXPORT_SYMBOL(ptp_clock_register);
301
302int 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}
320EXPORT_SYMBOL(ptp_clock_unregister);
321
322void 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}
347EXPORT_SYMBOL(ptp_clock_event);
348
349int ptp_clock_index(struct ptp_clock *ptp)
350{
351	return ptp->index;
352}
353EXPORT_SYMBOL(ptp_clock_index);
354
355int 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}
371EXPORT_SYMBOL(ptp_find_pin);
372
373int 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}
386EXPORT_SYMBOL(ptp_find_pin_unlocked);
387
388int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
389{
390	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
391}
392EXPORT_SYMBOL(ptp_schedule_worker);
393
394void ptp_cancel_worker_sync(struct ptp_clock *ptp)
395{
396	kthread_cancel_delayed_work_sync(&ptp->aux_work);
397}
398EXPORT_SYMBOL(ptp_cancel_worker_sync);
399
400/* module operations */
401
402static 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
409static 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
429no_region:
430	class_destroy(ptp_class);
431	return err;
432}
433
434subsys_initcall(ptp_init);
435module_exit(ptp_exit);
436
437MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
438MODULE_DESCRIPTION("PTP clocks support");
439MODULE_LICENSE("GPL");
440