xref: /openbmc/linux/drivers/net/ethernet/ti/cpts.c (revision 82df5b73)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * TI Common Platform Time Sync
4  *
5  * Copyright (C) 2012 Richard Cochran <richardcochran@gmail.com>
6  *
7  */
8 #include <linux/clk-provider.h>
9 #include <linux/err.h>
10 #include <linux/if.h>
11 #include <linux/hrtimer.h>
12 #include <linux/module.h>
13 #include <linux/net_tstamp.h>
14 #include <linux/ptp_classify.h>
15 #include <linux/time.h>
16 #include <linux/uaccess.h>
17 #include <linux/workqueue.h>
18 #include <linux/if_ether.h>
19 #include <linux/if_vlan.h>
20 
21 #include "cpts.h"
22 
23 #define CPTS_SKB_TX_WORK_TIMEOUT 1 /* jiffies */
24 #define CPTS_SKB_RX_TX_TMO 100 /*ms */
25 #define CPTS_EVENT_RX_TX_TIMEOUT (100) /* ms */
26 
27 struct cpts_skb_cb_data {
28 	u32 skb_mtype_seqid;
29 	unsigned long tmo;
30 };
31 
32 #define cpts_read32(c, r)	readl_relaxed(&c->reg->r)
33 #define cpts_write32(c, v, r)	writel_relaxed(v, &c->reg->r)
34 
35 static int cpts_event_port(struct cpts_event *event)
36 {
37 	return (event->high >> PORT_NUMBER_SHIFT) & PORT_NUMBER_MASK;
38 }
39 
40 static int event_expired(struct cpts_event *event)
41 {
42 	return time_after(jiffies, event->tmo);
43 }
44 
45 static int event_type(struct cpts_event *event)
46 {
47 	return (event->high >> EVENT_TYPE_SHIFT) & EVENT_TYPE_MASK;
48 }
49 
50 static int cpts_fifo_pop(struct cpts *cpts, u32 *high, u32 *low)
51 {
52 	u32 r = cpts_read32(cpts, intstat_raw);
53 
54 	if (r & TS_PEND_RAW) {
55 		*high = cpts_read32(cpts, event_high);
56 		*low  = cpts_read32(cpts, event_low);
57 		cpts_write32(cpts, EVENT_POP, event_pop);
58 		return 0;
59 	}
60 	return -1;
61 }
62 
63 static int cpts_purge_events(struct cpts *cpts)
64 {
65 	struct list_head *this, *next;
66 	struct cpts_event *event;
67 	int removed = 0;
68 
69 	list_for_each_safe(this, next, &cpts->events) {
70 		event = list_entry(this, struct cpts_event, list);
71 		if (event_expired(event)) {
72 			list_del_init(&event->list);
73 			list_add(&event->list, &cpts->pool);
74 			++removed;
75 		}
76 	}
77 
78 	if (removed)
79 		dev_dbg(cpts->dev, "cpts: event pool cleaned up %d\n", removed);
80 	return removed ? 0 : -1;
81 }
82 
83 static void cpts_purge_txq(struct cpts *cpts)
84 {
85 	struct cpts_skb_cb_data *skb_cb;
86 	struct sk_buff *skb, *tmp;
87 	int removed = 0;
88 
89 	skb_queue_walk_safe(&cpts->txq, skb, tmp) {
90 		skb_cb = (struct cpts_skb_cb_data *)skb->cb;
91 		if (time_after(jiffies, skb_cb->tmo)) {
92 			__skb_unlink(skb, &cpts->txq);
93 			dev_consume_skb_any(skb);
94 			++removed;
95 		}
96 	}
97 
98 	if (removed)
99 		dev_dbg(cpts->dev, "txq cleaned up %d\n", removed);
100 }
101 
102 /*
103  * Returns zero if matching event type was found.
104  */
105 static int cpts_fifo_read(struct cpts *cpts, int match)
106 {
107 	struct ptp_clock_event pevent;
108 	bool need_schedule = false;
109 	struct cpts_event *event;
110 	unsigned long flags;
111 	int i, type = -1;
112 	u32 hi, lo;
113 
114 	spin_lock_irqsave(&cpts->lock, flags);
115 
116 	for (i = 0; i < CPTS_FIFO_DEPTH; i++) {
117 		if (cpts_fifo_pop(cpts, &hi, &lo))
118 			break;
119 
120 		if (list_empty(&cpts->pool) && cpts_purge_events(cpts)) {
121 			dev_warn(cpts->dev, "cpts: event pool empty\n");
122 			break;
123 		}
124 
125 		event = list_first_entry(&cpts->pool, struct cpts_event, list);
126 		event->high = hi;
127 		event->low = lo;
128 		event->timestamp = timecounter_cyc2time(&cpts->tc, event->low);
129 		type = event_type(event);
130 
131 		dev_dbg(cpts->dev, "CPTS_EV: %d high:%08X low:%08x\n",
132 			type, event->high, event->low);
133 		switch (type) {
134 		case CPTS_EV_PUSH:
135 			WRITE_ONCE(cpts->cur_timestamp, lo);
136 			timecounter_read(&cpts->tc);
137 			if (cpts->mult_new) {
138 				cpts->cc.mult = cpts->mult_new;
139 				cpts->mult_new = 0;
140 			}
141 			if (!cpts->irq_poll)
142 				complete(&cpts->ts_push_complete);
143 			break;
144 		case CPTS_EV_TX:
145 		case CPTS_EV_RX:
146 			event->tmo = jiffies +
147 				msecs_to_jiffies(CPTS_EVENT_RX_TX_TIMEOUT);
148 
149 			list_del_init(&event->list);
150 			list_add_tail(&event->list, &cpts->events);
151 			need_schedule = true;
152 			break;
153 		case CPTS_EV_ROLL:
154 		case CPTS_EV_HALF:
155 			break;
156 		case CPTS_EV_HW:
157 			pevent.timestamp = event->timestamp;
158 			pevent.type = PTP_CLOCK_EXTTS;
159 			pevent.index = cpts_event_port(event) - 1;
160 			ptp_clock_event(cpts->clock, &pevent);
161 			break;
162 		default:
163 			dev_err(cpts->dev, "cpts: unknown event type\n");
164 			break;
165 		}
166 		if (type == match)
167 			break;
168 	}
169 
170 	spin_unlock_irqrestore(&cpts->lock, flags);
171 
172 	if (!cpts->irq_poll && need_schedule)
173 		ptp_schedule_worker(cpts->clock, 0);
174 
175 	return type == match ? 0 : -1;
176 }
177 
178 void cpts_misc_interrupt(struct cpts *cpts)
179 {
180 	cpts_fifo_read(cpts, -1);
181 }
182 EXPORT_SYMBOL_GPL(cpts_misc_interrupt);
183 
184 static u64 cpts_systim_read(const struct cyclecounter *cc)
185 {
186 	struct cpts *cpts = container_of(cc, struct cpts, cc);
187 
188 	return READ_ONCE(cpts->cur_timestamp);
189 }
190 
191 static void cpts_update_cur_time(struct cpts *cpts, int match,
192 				 struct ptp_system_timestamp *sts)
193 {
194 	unsigned long flags;
195 
196 	reinit_completion(&cpts->ts_push_complete);
197 
198 	/* use spin_lock_irqsave() here as it has to run very fast */
199 	spin_lock_irqsave(&cpts->lock, flags);
200 	ptp_read_system_prets(sts);
201 	cpts_write32(cpts, TS_PUSH, ts_push);
202 	cpts_read32(cpts, ts_push);
203 	ptp_read_system_postts(sts);
204 	spin_unlock_irqrestore(&cpts->lock, flags);
205 
206 	if (cpts->irq_poll && cpts_fifo_read(cpts, match) && match != -1)
207 		dev_err(cpts->dev, "cpts: unable to obtain a time stamp\n");
208 
209 	if (!cpts->irq_poll &&
210 	    !wait_for_completion_timeout(&cpts->ts_push_complete, HZ))
211 		dev_err(cpts->dev, "cpts: obtain a time stamp timeout\n");
212 }
213 
214 /* PTP clock operations */
215 
216 static int cpts_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
217 {
218 	struct cpts *cpts = container_of(ptp, struct cpts, info);
219 	int neg_adj = 0;
220 	u32 diff, mult;
221 	u64 adj;
222 
223 	if (ppb < 0) {
224 		neg_adj = 1;
225 		ppb = -ppb;
226 	}
227 	mult = cpts->cc_mult;
228 	adj = mult;
229 	adj *= ppb;
230 	diff = div_u64(adj, 1000000000ULL);
231 
232 	mutex_lock(&cpts->ptp_clk_mutex);
233 
234 	cpts->mult_new = neg_adj ? mult - diff : mult + diff;
235 
236 	cpts_update_cur_time(cpts, CPTS_EV_PUSH, NULL);
237 
238 	mutex_unlock(&cpts->ptp_clk_mutex);
239 	return 0;
240 }
241 
242 static int cpts_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
243 {
244 	struct cpts *cpts = container_of(ptp, struct cpts, info);
245 
246 	mutex_lock(&cpts->ptp_clk_mutex);
247 	timecounter_adjtime(&cpts->tc, delta);
248 	mutex_unlock(&cpts->ptp_clk_mutex);
249 
250 	return 0;
251 }
252 
253 static int cpts_ptp_gettimeex(struct ptp_clock_info *ptp,
254 			      struct timespec64 *ts,
255 			      struct ptp_system_timestamp *sts)
256 {
257 	struct cpts *cpts = container_of(ptp, struct cpts, info);
258 	u64 ns;
259 
260 	mutex_lock(&cpts->ptp_clk_mutex);
261 
262 	cpts_update_cur_time(cpts, CPTS_EV_PUSH, sts);
263 
264 	ns = timecounter_read(&cpts->tc);
265 	mutex_unlock(&cpts->ptp_clk_mutex);
266 
267 	*ts = ns_to_timespec64(ns);
268 
269 	return 0;
270 }
271 
272 static int cpts_ptp_settime(struct ptp_clock_info *ptp,
273 			    const struct timespec64 *ts)
274 {
275 	struct cpts *cpts = container_of(ptp, struct cpts, info);
276 	u64 ns;
277 
278 	ns = timespec64_to_ns(ts);
279 
280 	mutex_lock(&cpts->ptp_clk_mutex);
281 	timecounter_init(&cpts->tc, &cpts->cc, ns);
282 	mutex_unlock(&cpts->ptp_clk_mutex);
283 
284 	return 0;
285 }
286 
287 static int cpts_extts_enable(struct cpts *cpts, u32 index, int on)
288 {
289 	u32 v;
290 
291 	if (((cpts->hw_ts_enable & BIT(index)) >> index) == on)
292 		return 0;
293 
294 	mutex_lock(&cpts->ptp_clk_mutex);
295 
296 	v = cpts_read32(cpts, control);
297 	if (on) {
298 		v |= BIT(8 + index);
299 		cpts->hw_ts_enable |= BIT(index);
300 	} else {
301 		v &= ~BIT(8 + index);
302 		cpts->hw_ts_enable &= ~BIT(index);
303 	}
304 	cpts_write32(cpts, v, control);
305 
306 	mutex_unlock(&cpts->ptp_clk_mutex);
307 
308 	return 0;
309 }
310 
311 static int cpts_ptp_enable(struct ptp_clock_info *ptp,
312 			   struct ptp_clock_request *rq, int on)
313 {
314 	struct cpts *cpts = container_of(ptp, struct cpts, info);
315 
316 	switch (rq->type) {
317 	case PTP_CLK_REQ_EXTTS:
318 		return cpts_extts_enable(cpts, rq->extts.index, on);
319 	default:
320 		break;
321 	}
322 
323 	return -EOPNOTSUPP;
324 }
325 
326 static bool cpts_match_tx_ts(struct cpts *cpts, struct cpts_event *event)
327 {
328 	struct sk_buff_head txq_list;
329 	struct sk_buff *skb, *tmp;
330 	unsigned long flags;
331 	bool found = false;
332 	u32 mtype_seqid;
333 
334 	mtype_seqid = event->high &
335 		      ((MESSAGE_TYPE_MASK << MESSAGE_TYPE_SHIFT) |
336 		       (SEQUENCE_ID_MASK << SEQUENCE_ID_SHIFT) |
337 		       (EVENT_TYPE_MASK << EVENT_TYPE_SHIFT));
338 
339 	__skb_queue_head_init(&txq_list);
340 
341 	spin_lock_irqsave(&cpts->txq.lock, flags);
342 	skb_queue_splice_init(&cpts->txq, &txq_list);
343 	spin_unlock_irqrestore(&cpts->txq.lock, flags);
344 
345 	skb_queue_walk_safe(&txq_list, skb, tmp) {
346 		struct skb_shared_hwtstamps ssh;
347 		struct cpts_skb_cb_data *skb_cb =
348 					(struct cpts_skb_cb_data *)skb->cb;
349 
350 		if (mtype_seqid == skb_cb->skb_mtype_seqid) {
351 			memset(&ssh, 0, sizeof(ssh));
352 			ssh.hwtstamp = ns_to_ktime(event->timestamp);
353 			skb_tstamp_tx(skb, &ssh);
354 			found = true;
355 			__skb_unlink(skb, &txq_list);
356 			dev_consume_skb_any(skb);
357 			dev_dbg(cpts->dev, "match tx timestamp mtype_seqid %08x\n",
358 				mtype_seqid);
359 			break;
360 		}
361 
362 		if (time_after(jiffies, skb_cb->tmo)) {
363 			/* timeout any expired skbs over 1s */
364 			dev_dbg(cpts->dev, "expiring tx timestamp from txq\n");
365 			__skb_unlink(skb, &txq_list);
366 			dev_consume_skb_any(skb);
367 		}
368 	}
369 
370 	spin_lock_irqsave(&cpts->txq.lock, flags);
371 	skb_queue_splice(&txq_list, &cpts->txq);
372 	spin_unlock_irqrestore(&cpts->txq.lock, flags);
373 
374 	return found;
375 }
376 
377 static void cpts_process_events(struct cpts *cpts)
378 {
379 	struct list_head *this, *next;
380 	struct cpts_event *event;
381 	LIST_HEAD(events_free);
382 	unsigned long flags;
383 	LIST_HEAD(events);
384 
385 	spin_lock_irqsave(&cpts->lock, flags);
386 	list_splice_init(&cpts->events, &events);
387 	spin_unlock_irqrestore(&cpts->lock, flags);
388 
389 	list_for_each_safe(this, next, &events) {
390 		event = list_entry(this, struct cpts_event, list);
391 		if (cpts_match_tx_ts(cpts, event) ||
392 		    time_after(jiffies, event->tmo)) {
393 			list_del_init(&event->list);
394 			list_add(&event->list, &events_free);
395 		}
396 	}
397 
398 	spin_lock_irqsave(&cpts->lock, flags);
399 	list_splice_tail(&events, &cpts->events);
400 	list_splice_tail(&events_free, &cpts->pool);
401 	spin_unlock_irqrestore(&cpts->lock, flags);
402 }
403 
404 static long cpts_overflow_check(struct ptp_clock_info *ptp)
405 {
406 	struct cpts *cpts = container_of(ptp, struct cpts, info);
407 	unsigned long delay = cpts->ov_check_period;
408 	unsigned long flags;
409 	u64 ns;
410 
411 	mutex_lock(&cpts->ptp_clk_mutex);
412 
413 	cpts_update_cur_time(cpts, -1, NULL);
414 	ns = timecounter_read(&cpts->tc);
415 
416 	cpts_process_events(cpts);
417 
418 	spin_lock_irqsave(&cpts->txq.lock, flags);
419 	if (!skb_queue_empty(&cpts->txq)) {
420 		cpts_purge_txq(cpts);
421 		if (!skb_queue_empty(&cpts->txq))
422 			delay = CPTS_SKB_TX_WORK_TIMEOUT;
423 	}
424 	spin_unlock_irqrestore(&cpts->txq.lock, flags);
425 
426 	dev_dbg(cpts->dev, "cpts overflow check at %lld\n", ns);
427 	mutex_unlock(&cpts->ptp_clk_mutex);
428 	return (long)delay;
429 }
430 
431 static const struct ptp_clock_info cpts_info = {
432 	.owner		= THIS_MODULE,
433 	.name		= "CTPS timer",
434 	.max_adj	= 1000000,
435 	.n_ext_ts	= 0,
436 	.n_pins		= 0,
437 	.pps		= 0,
438 	.adjfreq	= cpts_ptp_adjfreq,
439 	.adjtime	= cpts_ptp_adjtime,
440 	.gettimex64	= cpts_ptp_gettimeex,
441 	.settime64	= cpts_ptp_settime,
442 	.enable		= cpts_ptp_enable,
443 	.do_aux_work	= cpts_overflow_check,
444 };
445 
446 static int cpts_skb_get_mtype_seqid(struct sk_buff *skb, u32 *mtype_seqid)
447 {
448 	unsigned int ptp_class = ptp_classify_raw(skb);
449 	u8 *msgtype, *data = skb->data;
450 	unsigned int offset = 0;
451 	u16 *seqid;
452 
453 	if (ptp_class == PTP_CLASS_NONE)
454 		return 0;
455 
456 	if (ptp_class & PTP_CLASS_VLAN)
457 		offset += VLAN_HLEN;
458 
459 	switch (ptp_class & PTP_CLASS_PMASK) {
460 	case PTP_CLASS_IPV4:
461 		offset += ETH_HLEN + IPV4_HLEN(data + offset) + UDP_HLEN;
462 		break;
463 	case PTP_CLASS_IPV6:
464 		offset += ETH_HLEN + IP6_HLEN + UDP_HLEN;
465 		break;
466 	case PTP_CLASS_L2:
467 		offset += ETH_HLEN;
468 		break;
469 	default:
470 		return 0;
471 	}
472 
473 	if (skb->len + ETH_HLEN < offset + OFF_PTP_SEQUENCE_ID + sizeof(*seqid))
474 		return 0;
475 
476 	if (unlikely(ptp_class & PTP_CLASS_V1))
477 		msgtype = data + offset + OFF_PTP_CONTROL;
478 	else
479 		msgtype = data + offset;
480 
481 	seqid = (u16 *)(data + offset + OFF_PTP_SEQUENCE_ID);
482 	*mtype_seqid = (*msgtype & MESSAGE_TYPE_MASK) << MESSAGE_TYPE_SHIFT;
483 	*mtype_seqid |= (ntohs(*seqid) & SEQUENCE_ID_MASK) << SEQUENCE_ID_SHIFT;
484 
485 	return 1;
486 }
487 
488 static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb,
489 			int ev_type, u32 skb_mtype_seqid)
490 {
491 	struct list_head *this, *next;
492 	struct cpts_event *event;
493 	unsigned long flags;
494 	u32 mtype_seqid;
495 	u64 ns = 0;
496 
497 	cpts_fifo_read(cpts, -1);
498 	spin_lock_irqsave(&cpts->lock, flags);
499 	list_for_each_safe(this, next, &cpts->events) {
500 		event = list_entry(this, struct cpts_event, list);
501 		if (event_expired(event)) {
502 			list_del_init(&event->list);
503 			list_add(&event->list, &cpts->pool);
504 			continue;
505 		}
506 
507 		mtype_seqid = event->high &
508 			      ((MESSAGE_TYPE_MASK << MESSAGE_TYPE_SHIFT) |
509 			       (SEQUENCE_ID_MASK << SEQUENCE_ID_SHIFT) |
510 			       (EVENT_TYPE_MASK << EVENT_TYPE_SHIFT));
511 
512 		if (mtype_seqid == skb_mtype_seqid) {
513 			ns = event->timestamp;
514 			list_del_init(&event->list);
515 			list_add(&event->list, &cpts->pool);
516 			break;
517 		}
518 	}
519 	spin_unlock_irqrestore(&cpts->lock, flags);
520 
521 	return ns;
522 }
523 
524 void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
525 {
526 	struct cpts_skb_cb_data *skb_cb = (struct cpts_skb_cb_data *)skb->cb;
527 	struct skb_shared_hwtstamps *ssh;
528 	int ret;
529 	u64 ns;
530 
531 	ret = cpts_skb_get_mtype_seqid(skb, &skb_cb->skb_mtype_seqid);
532 	if (!ret)
533 		return;
534 
535 	skb_cb->skb_mtype_seqid |= (CPTS_EV_RX << EVENT_TYPE_SHIFT);
536 
537 	dev_dbg(cpts->dev, "%s mtype seqid %08x\n",
538 		__func__, skb_cb->skb_mtype_seqid);
539 
540 	ns = cpts_find_ts(cpts, skb, CPTS_EV_RX, skb_cb->skb_mtype_seqid);
541 	if (!ns)
542 		return;
543 	ssh = skb_hwtstamps(skb);
544 	memset(ssh, 0, sizeof(*ssh));
545 	ssh->hwtstamp = ns_to_ktime(ns);
546 }
547 EXPORT_SYMBOL_GPL(cpts_rx_timestamp);
548 
549 void cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb)
550 {
551 	struct cpts_skb_cb_data *skb_cb = (struct cpts_skb_cb_data *)skb->cb;
552 	int ret;
553 
554 	if (!(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
555 		return;
556 
557 	ret = cpts_skb_get_mtype_seqid(skb, &skb_cb->skb_mtype_seqid);
558 	if (!ret)
559 		return;
560 
561 	skb_cb->skb_mtype_seqid |= (CPTS_EV_TX << EVENT_TYPE_SHIFT);
562 
563 	dev_dbg(cpts->dev, "%s mtype seqid %08x\n",
564 		__func__, skb_cb->skb_mtype_seqid);
565 
566 	/* Always defer TX TS processing to PTP worker */
567 	skb_get(skb);
568 	/* get the timestamp for timeouts */
569 	skb_cb->tmo = jiffies + msecs_to_jiffies(CPTS_SKB_RX_TX_TMO);
570 	skb_queue_tail(&cpts->txq, skb);
571 	ptp_schedule_worker(cpts->clock, 0);
572 }
573 EXPORT_SYMBOL_GPL(cpts_tx_timestamp);
574 
575 int cpts_register(struct cpts *cpts)
576 {
577 	int err, i;
578 
579 	skb_queue_head_init(&cpts->txq);
580 	INIT_LIST_HEAD(&cpts->events);
581 	INIT_LIST_HEAD(&cpts->pool);
582 	for (i = 0; i < CPTS_MAX_EVENTS; i++)
583 		list_add(&cpts->pool_data[i].list, &cpts->pool);
584 
585 	clk_enable(cpts->refclk);
586 
587 	cpts_write32(cpts, CPTS_EN, control);
588 	cpts_write32(cpts, TS_PEND_EN, int_enable);
589 
590 	timecounter_init(&cpts->tc, &cpts->cc, ktime_get_real_ns());
591 
592 	cpts->clock = ptp_clock_register(&cpts->info, cpts->dev);
593 	if (IS_ERR(cpts->clock)) {
594 		err = PTR_ERR(cpts->clock);
595 		cpts->clock = NULL;
596 		goto err_ptp;
597 	}
598 	cpts->phc_index = ptp_clock_index(cpts->clock);
599 
600 	ptp_schedule_worker(cpts->clock, cpts->ov_check_period);
601 	return 0;
602 
603 err_ptp:
604 	clk_disable(cpts->refclk);
605 	return err;
606 }
607 EXPORT_SYMBOL_GPL(cpts_register);
608 
609 void cpts_unregister(struct cpts *cpts)
610 {
611 	if (WARN_ON(!cpts->clock))
612 		return;
613 
614 	ptp_clock_unregister(cpts->clock);
615 	cpts->clock = NULL;
616 
617 	cpts_write32(cpts, 0, int_enable);
618 	cpts_write32(cpts, 0, control);
619 
620 	/* Drop all packet */
621 	skb_queue_purge(&cpts->txq);
622 
623 	clk_disable(cpts->refclk);
624 }
625 EXPORT_SYMBOL_GPL(cpts_unregister);
626 
627 static void cpts_calc_mult_shift(struct cpts *cpts)
628 {
629 	u64 frac, maxsec, ns;
630 	u32 freq;
631 
632 	freq = clk_get_rate(cpts->refclk);
633 
634 	/* Calc the maximum number of seconds which we can run before
635 	 * wrapping around.
636 	 */
637 	maxsec = cpts->cc.mask;
638 	do_div(maxsec, freq);
639 	/* limit conversation rate to 10 sec as higher values will produce
640 	 * too small mult factors and so reduce the conversion accuracy
641 	 */
642 	if (maxsec > 10)
643 		maxsec = 10;
644 
645 	/* Calc overflow check period (maxsec / 2) */
646 	cpts->ov_check_period = (HZ * maxsec) / 2;
647 	dev_info(cpts->dev, "cpts: overflow check period %lu (jiffies)\n",
648 		 cpts->ov_check_period);
649 
650 	if (cpts->cc.mult || cpts->cc.shift)
651 		return;
652 
653 	clocks_calc_mult_shift(&cpts->cc.mult, &cpts->cc.shift,
654 			       freq, NSEC_PER_SEC, maxsec);
655 
656 	frac = 0;
657 	ns = cyclecounter_cyc2ns(&cpts->cc, freq, cpts->cc.mask, &frac);
658 
659 	dev_info(cpts->dev,
660 		 "CPTS: ref_clk_freq:%u calc_mult:%u calc_shift:%u error:%lld nsec/sec\n",
661 		 freq, cpts->cc.mult, cpts->cc.shift, (ns - NSEC_PER_SEC));
662 }
663 
664 static int cpts_of_mux_clk_setup(struct cpts *cpts, struct device_node *node)
665 {
666 	struct device_node *refclk_np;
667 	const char **parent_names;
668 	unsigned int num_parents;
669 	struct clk_hw *clk_hw;
670 	int ret = -EINVAL;
671 	u32 *mux_table;
672 
673 	refclk_np = of_get_child_by_name(node, "cpts-refclk-mux");
674 	if (!refclk_np)
675 		/* refclk selection supported not for all SoCs */
676 		return 0;
677 
678 	num_parents = of_clk_get_parent_count(refclk_np);
679 	if (num_parents < 1) {
680 		dev_err(cpts->dev, "mux-clock %s must have parents\n",
681 			refclk_np->name);
682 		goto mux_fail;
683 	}
684 
685 	parent_names = devm_kzalloc(cpts->dev, (sizeof(char *) * num_parents),
686 				    GFP_KERNEL);
687 
688 	mux_table = devm_kzalloc(cpts->dev, sizeof(*mux_table) * num_parents,
689 				 GFP_KERNEL);
690 	if (!mux_table || !parent_names) {
691 		ret = -ENOMEM;
692 		goto mux_fail;
693 	}
694 
695 	of_clk_parent_fill(refclk_np, parent_names, num_parents);
696 
697 	ret = of_property_read_variable_u32_array(refclk_np, "ti,mux-tbl",
698 						  mux_table,
699 						  num_parents, num_parents);
700 	if (ret < 0)
701 		goto mux_fail;
702 
703 	clk_hw = clk_hw_register_mux_table(cpts->dev, refclk_np->name,
704 					   parent_names, num_parents,
705 					   0,
706 					   &cpts->reg->rftclk_sel, 0, 0x1F,
707 					   0, mux_table, NULL);
708 	if (IS_ERR(clk_hw)) {
709 		ret = PTR_ERR(clk_hw);
710 		goto mux_fail;
711 	}
712 
713 	ret = devm_add_action_or_reset(cpts->dev,
714 				       (void(*)(void *))clk_hw_unregister_mux,
715 				       clk_hw);
716 	if (ret) {
717 		dev_err(cpts->dev, "add clkmux unreg action %d", ret);
718 		goto mux_fail;
719 	}
720 
721 	ret = of_clk_add_hw_provider(refclk_np, of_clk_hw_simple_get, clk_hw);
722 	if (ret)
723 		goto mux_fail;
724 
725 	ret = devm_add_action_or_reset(cpts->dev,
726 				       (void(*)(void *))of_clk_del_provider,
727 				       refclk_np);
728 	if (ret) {
729 		dev_err(cpts->dev, "add clkmux provider unreg action %d", ret);
730 		goto mux_fail;
731 	}
732 
733 	return ret;
734 
735 mux_fail:
736 	of_node_put(refclk_np);
737 	return ret;
738 }
739 
740 static int cpts_of_parse(struct cpts *cpts, struct device_node *node)
741 {
742 	int ret = -EINVAL;
743 	u32 prop;
744 
745 	if (!of_property_read_u32(node, "cpts_clock_mult", &prop))
746 		cpts->cc.mult = prop;
747 
748 	if (!of_property_read_u32(node, "cpts_clock_shift", &prop))
749 		cpts->cc.shift = prop;
750 
751 	if ((cpts->cc.mult && !cpts->cc.shift) ||
752 	    (!cpts->cc.mult && cpts->cc.shift))
753 		goto of_error;
754 
755 	return cpts_of_mux_clk_setup(cpts, node);
756 
757 of_error:
758 	dev_err(cpts->dev, "CPTS: Missing property in the DT.\n");
759 	return ret;
760 }
761 
762 struct cpts *cpts_create(struct device *dev, void __iomem *regs,
763 			 struct device_node *node, u32 n_ext_ts)
764 {
765 	struct cpts *cpts;
766 	int ret;
767 
768 	cpts = devm_kzalloc(dev, sizeof(*cpts), GFP_KERNEL);
769 	if (!cpts)
770 		return ERR_PTR(-ENOMEM);
771 
772 	cpts->dev = dev;
773 	cpts->reg = (struct cpsw_cpts __iomem *)regs;
774 	cpts->irq_poll = true;
775 	spin_lock_init(&cpts->lock);
776 	mutex_init(&cpts->ptp_clk_mutex);
777 	init_completion(&cpts->ts_push_complete);
778 
779 	ret = cpts_of_parse(cpts, node);
780 	if (ret)
781 		return ERR_PTR(ret);
782 
783 	cpts->refclk = devm_get_clk_from_child(dev, node, "cpts");
784 	if (IS_ERR(cpts->refclk))
785 		/* try get clk from dev node for compatibility */
786 		cpts->refclk = devm_clk_get(dev, "cpts");
787 
788 	if (IS_ERR(cpts->refclk)) {
789 		dev_err(dev, "Failed to get cpts refclk %ld\n",
790 			PTR_ERR(cpts->refclk));
791 		return ERR_CAST(cpts->refclk);
792 	}
793 
794 	ret = clk_prepare(cpts->refclk);
795 	if (ret)
796 		return ERR_PTR(ret);
797 
798 	cpts->cc.read = cpts_systim_read;
799 	cpts->cc.mask = CLOCKSOURCE_MASK(32);
800 	cpts->info = cpts_info;
801 
802 	if (n_ext_ts)
803 		cpts->info.n_ext_ts = n_ext_ts;
804 
805 	cpts_calc_mult_shift(cpts);
806 	/* save cc.mult original value as it can be modified
807 	 * by cpts_ptp_adjfreq().
808 	 */
809 	cpts->cc_mult = cpts->cc.mult;
810 
811 	return cpts;
812 }
813 EXPORT_SYMBOL_GPL(cpts_create);
814 
815 void cpts_release(struct cpts *cpts)
816 {
817 	if (!cpts)
818 		return;
819 
820 	if (WARN_ON(!cpts->refclk))
821 		return;
822 
823 	clk_unprepare(cpts->refclk);
824 }
825 EXPORT_SYMBOL_GPL(cpts_release);
826 
827 MODULE_LICENSE("GPL v2");
828 MODULE_DESCRIPTION("TI CPTS driver");
829 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
830