1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright(c) 2017 - 2021 Pensando Systems, Inc */
3 
4 #include <linux/netdevice.h>
5 #include <linux/etherdevice.h>
6 
7 #include "ionic.h"
8 #include "ionic_bus.h"
9 #include "ionic_lif.h"
10 #include "ionic_ethtool.h"
11 
ionic_hwstamp_tx_mode(int config_tx_type)12 static int ionic_hwstamp_tx_mode(int config_tx_type)
13 {
14 	switch (config_tx_type) {
15 	case HWTSTAMP_TX_OFF:
16 		return IONIC_TXSTAMP_OFF;
17 	case HWTSTAMP_TX_ON:
18 		return IONIC_TXSTAMP_ON;
19 	case HWTSTAMP_TX_ONESTEP_SYNC:
20 		return IONIC_TXSTAMP_ONESTEP_SYNC;
21 	case HWTSTAMP_TX_ONESTEP_P2P:
22 		return IONIC_TXSTAMP_ONESTEP_P2P;
23 	default:
24 		return -ERANGE;
25 	}
26 }
27 
ionic_hwstamp_rx_filt(int config_rx_filter)28 static u64 ionic_hwstamp_rx_filt(int config_rx_filter)
29 {
30 	switch (config_rx_filter) {
31 	case HWTSTAMP_FILTER_PTP_V1_L4_EVENT:
32 		return IONIC_PKT_CLS_PTP1_ALL;
33 	case HWTSTAMP_FILTER_PTP_V1_L4_SYNC:
34 		return IONIC_PKT_CLS_PTP1_SYNC;
35 	case HWTSTAMP_FILTER_PTP_V1_L4_DELAY_REQ:
36 		return IONIC_PKT_CLS_PTP1_SYNC | IONIC_PKT_CLS_PTP1_DREQ;
37 
38 	case HWTSTAMP_FILTER_PTP_V2_L4_EVENT:
39 		return IONIC_PKT_CLS_PTP2_L4_ALL;
40 	case HWTSTAMP_FILTER_PTP_V2_L4_SYNC:
41 		return IONIC_PKT_CLS_PTP2_L4_SYNC;
42 	case HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ:
43 		return IONIC_PKT_CLS_PTP2_L4_SYNC | IONIC_PKT_CLS_PTP2_L4_DREQ;
44 
45 	case HWTSTAMP_FILTER_PTP_V2_L2_EVENT:
46 		return IONIC_PKT_CLS_PTP2_L2_ALL;
47 	case HWTSTAMP_FILTER_PTP_V2_L2_SYNC:
48 		return IONIC_PKT_CLS_PTP2_L2_SYNC;
49 	case HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ:
50 		return IONIC_PKT_CLS_PTP2_L2_SYNC | IONIC_PKT_CLS_PTP2_L2_DREQ;
51 
52 	case HWTSTAMP_FILTER_PTP_V2_EVENT:
53 		return IONIC_PKT_CLS_PTP2_ALL;
54 	case HWTSTAMP_FILTER_PTP_V2_SYNC:
55 		return IONIC_PKT_CLS_PTP2_SYNC;
56 	case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
57 		return IONIC_PKT_CLS_PTP2_SYNC | IONIC_PKT_CLS_PTP2_DREQ;
58 
59 	case HWTSTAMP_FILTER_NTP_ALL:
60 		return IONIC_PKT_CLS_NTP_ALL;
61 
62 	default:
63 		return 0;
64 	}
65 }
66 
ionic_lif_hwstamp_set_ts_config(struct ionic_lif * lif,struct hwtstamp_config * new_ts)67 static int ionic_lif_hwstamp_set_ts_config(struct ionic_lif *lif,
68 					   struct hwtstamp_config *new_ts)
69 {
70 	struct ionic *ionic = lif->ionic;
71 	struct hwtstamp_config *config;
72 	struct hwtstamp_config ts;
73 	int tx_mode = 0;
74 	u64 rx_filt = 0;
75 	int err, err2;
76 	bool rx_all;
77 	__le64 mask;
78 
79 	if (!lif->phc || !lif->phc->ptp)
80 		return -EOPNOTSUPP;
81 
82 	mutex_lock(&lif->phc->config_lock);
83 
84 	if (new_ts) {
85 		config = new_ts;
86 	} else {
87 		/* If called with new_ts == NULL, replay the previous request
88 		 * primarily for recovery after a FW_RESET.
89 		 * We saved the previous configuration request info, so copy
90 		 * the previous request for reference, clear the current state
91 		 * to match the device's reset state, and run with it.
92 		 */
93 		config = &ts;
94 		memcpy(config, &lif->phc->ts_config, sizeof(*config));
95 		memset(&lif->phc->ts_config, 0, sizeof(lif->phc->ts_config));
96 		lif->phc->ts_config_tx_mode = 0;
97 		lif->phc->ts_config_rx_filt = 0;
98 	}
99 
100 	tx_mode = ionic_hwstamp_tx_mode(config->tx_type);
101 	if (tx_mode < 0) {
102 		err = tx_mode;
103 		goto err_queues;
104 	}
105 
106 	mask = cpu_to_le64(BIT_ULL(tx_mode));
107 	if ((ionic->ident.lif.eth.hwstamp_tx_modes & mask) != mask) {
108 		err = -ERANGE;
109 		goto err_queues;
110 	}
111 
112 	rx_filt = ionic_hwstamp_rx_filt(config->rx_filter);
113 	rx_all = config->rx_filter != HWTSTAMP_FILTER_NONE && !rx_filt;
114 
115 	mask = cpu_to_le64(rx_filt);
116 	if ((ionic->ident.lif.eth.hwstamp_rx_filters & mask) != mask) {
117 		rx_filt = 0;
118 		rx_all = true;
119 		config->rx_filter = HWTSTAMP_FILTER_ALL;
120 	}
121 
122 	dev_dbg(ionic->dev, "%s: config_rx_filter %d rx_filt %#llx rx_all %d\n",
123 		__func__, config->rx_filter, rx_filt, rx_all);
124 
125 	if (tx_mode) {
126 		err = ionic_lif_create_hwstamp_txq(lif);
127 		if (err)
128 			goto err_queues;
129 	}
130 
131 	if (rx_filt) {
132 		err = ionic_lif_create_hwstamp_rxq(lif);
133 		if (err)
134 			goto err_queues;
135 	}
136 
137 	if (tx_mode != lif->phc->ts_config_tx_mode) {
138 		err = ionic_lif_set_hwstamp_txmode(lif, tx_mode);
139 		if (err)
140 			goto err_txmode;
141 	}
142 
143 	if (rx_filt != lif->phc->ts_config_rx_filt) {
144 		err = ionic_lif_set_hwstamp_rxfilt(lif, rx_filt);
145 		if (err)
146 			goto err_rxfilt;
147 	}
148 
149 	if (rx_all != (lif->phc->ts_config.rx_filter == HWTSTAMP_FILTER_ALL)) {
150 		err = ionic_lif_config_hwstamp_rxq_all(lif, rx_all);
151 		if (err)
152 			goto err_rxall;
153 	}
154 
155 	memcpy(&lif->phc->ts_config, config, sizeof(*config));
156 	lif->phc->ts_config_rx_filt = rx_filt;
157 	lif->phc->ts_config_tx_mode = tx_mode;
158 
159 	mutex_unlock(&lif->phc->config_lock);
160 
161 	return 0;
162 
163 err_rxall:
164 	if (rx_filt != lif->phc->ts_config_rx_filt) {
165 		rx_filt = lif->phc->ts_config_rx_filt;
166 		err2 = ionic_lif_set_hwstamp_rxfilt(lif, rx_filt);
167 		if (err2)
168 			dev_err(ionic->dev,
169 				"Failed to revert rx timestamp filter: %d\n", err2);
170 	}
171 err_rxfilt:
172 	if (tx_mode != lif->phc->ts_config_tx_mode) {
173 		tx_mode = lif->phc->ts_config_tx_mode;
174 		err2 = ionic_lif_set_hwstamp_txmode(lif, tx_mode);
175 		if (err2)
176 			dev_err(ionic->dev,
177 				"Failed to revert tx timestamp mode: %d\n", err2);
178 	}
179 err_txmode:
180 	/* special queues remain allocated, just unused */
181 err_queues:
182 	mutex_unlock(&lif->phc->config_lock);
183 	return err;
184 }
185 
ionic_lif_hwstamp_set(struct ionic_lif * lif,struct ifreq * ifr)186 int ionic_lif_hwstamp_set(struct ionic_lif *lif, struct ifreq *ifr)
187 {
188 	struct hwtstamp_config config;
189 	int err;
190 
191 	if (!lif->phc || !lif->phc->ptp)
192 		return -EOPNOTSUPP;
193 
194 	if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
195 		return -EFAULT;
196 
197 	mutex_lock(&lif->queue_lock);
198 	err = ionic_lif_hwstamp_set_ts_config(lif, &config);
199 	mutex_unlock(&lif->queue_lock);
200 	if (err) {
201 		netdev_info(lif->netdev, "hwstamp set failed: %d\n", err);
202 		return err;
203 	}
204 
205 	if (copy_to_user(ifr->ifr_data, &config, sizeof(config)))
206 		return -EFAULT;
207 
208 	return 0;
209 }
210 
ionic_lif_hwstamp_replay(struct ionic_lif * lif)211 void ionic_lif_hwstamp_replay(struct ionic_lif *lif)
212 {
213 	int err;
214 
215 	if (!lif->phc || !lif->phc->ptp)
216 		return;
217 
218 	mutex_lock(&lif->queue_lock);
219 	err = ionic_lif_hwstamp_set_ts_config(lif, NULL);
220 	mutex_unlock(&lif->queue_lock);
221 	if (err)
222 		netdev_info(lif->netdev, "hwstamp replay failed: %d\n", err);
223 }
224 
ionic_lif_hwstamp_recreate_queues(struct ionic_lif * lif)225 void ionic_lif_hwstamp_recreate_queues(struct ionic_lif *lif)
226 {
227 	int err;
228 
229 	if (!lif->phc || !lif->phc->ptp)
230 		return;
231 
232 	mutex_lock(&lif->phc->config_lock);
233 
234 	if (lif->phc->ts_config_tx_mode) {
235 		err = ionic_lif_create_hwstamp_txq(lif);
236 		if (err)
237 			netdev_info(lif->netdev, "hwstamp recreate txq failed: %d\n", err);
238 	}
239 
240 	if (lif->phc->ts_config_rx_filt) {
241 		err = ionic_lif_create_hwstamp_rxq(lif);
242 		if (err)
243 			netdev_info(lif->netdev, "hwstamp recreate rxq failed: %d\n", err);
244 	}
245 
246 	mutex_unlock(&lif->phc->config_lock);
247 }
248 
ionic_lif_hwstamp_get(struct ionic_lif * lif,struct ifreq * ifr)249 int ionic_lif_hwstamp_get(struct ionic_lif *lif, struct ifreq *ifr)
250 {
251 	struct hwtstamp_config config;
252 
253 	if (!lif->phc || !lif->phc->ptp)
254 		return -EOPNOTSUPP;
255 
256 	mutex_lock(&lif->phc->config_lock);
257 	memcpy(&config, &lif->phc->ts_config, sizeof(config));
258 	mutex_unlock(&lif->phc->config_lock);
259 
260 	if (copy_to_user(ifr->ifr_data, &config, sizeof(config)))
261 		return -EFAULT;
262 	return 0;
263 }
264 
ionic_hwstamp_read(struct ionic * ionic,struct ptp_system_timestamp * sts)265 static u64 ionic_hwstamp_read(struct ionic *ionic,
266 			      struct ptp_system_timestamp *sts)
267 {
268 	u32 tick_high_before, tick_high, tick_low;
269 
270 	/* read and discard low part to defeat hw staging of high part */
271 	ioread32(&ionic->idev.hwstamp_regs->tick_low);
272 
273 	tick_high_before = ioread32(&ionic->idev.hwstamp_regs->tick_high);
274 
275 	ptp_read_system_prets(sts);
276 	tick_low = ioread32(&ionic->idev.hwstamp_regs->tick_low);
277 	ptp_read_system_postts(sts);
278 
279 	tick_high = ioread32(&ionic->idev.hwstamp_regs->tick_high);
280 
281 	/* If tick_high changed, re-read tick_low once more.  Assume tick_high
282 	 * cannot change again so soon as in the span of re-reading tick_low.
283 	 */
284 	if (tick_high != tick_high_before) {
285 		ptp_read_system_prets(sts);
286 		tick_low = ioread32(&ionic->idev.hwstamp_regs->tick_low);
287 		ptp_read_system_postts(sts);
288 	}
289 
290 	return (u64)tick_low | ((u64)tick_high << 32);
291 }
292 
ionic_cc_read(const struct cyclecounter * cc)293 static u64 ionic_cc_read(const struct cyclecounter *cc)
294 {
295 	struct ionic_phc *phc = container_of(cc, struct ionic_phc, cc);
296 	struct ionic *ionic = phc->lif->ionic;
297 
298 	return ionic_hwstamp_read(ionic, NULL);
299 }
300 
ionic_setphc_cmd(struct ionic_phc * phc,struct ionic_admin_ctx * ctx)301 static int ionic_setphc_cmd(struct ionic_phc *phc, struct ionic_admin_ctx *ctx)
302 {
303 	ctx->work = COMPLETION_INITIALIZER_ONSTACK(ctx->work);
304 
305 	ctx->cmd.lif_setphc.opcode = IONIC_CMD_LIF_SETPHC;
306 	ctx->cmd.lif_setphc.lif_index = cpu_to_le16(phc->lif->index);
307 
308 	ctx->cmd.lif_setphc.tick = cpu_to_le64(phc->tc.cycle_last);
309 	ctx->cmd.lif_setphc.nsec = cpu_to_le64(phc->tc.nsec);
310 	ctx->cmd.lif_setphc.frac = cpu_to_le64(phc->tc.frac);
311 	ctx->cmd.lif_setphc.mult = cpu_to_le32(phc->cc.mult);
312 	ctx->cmd.lif_setphc.shift = cpu_to_le32(phc->cc.shift);
313 
314 	return ionic_adminq_post(phc->lif, ctx);
315 }
316 
ionic_phc_adjfine(struct ptp_clock_info * info,long scaled_ppm)317 static int ionic_phc_adjfine(struct ptp_clock_info *info, long scaled_ppm)
318 {
319 	struct ionic_phc *phc = container_of(info, struct ionic_phc, ptp_info);
320 	struct ionic_admin_ctx ctx = {};
321 	unsigned long irqflags;
322 	s64 adj;
323 	int err;
324 
325 	/* Reject phc adjustments during device upgrade */
326 	if (test_bit(IONIC_LIF_F_FW_RESET, phc->lif->state))
327 		return -EBUSY;
328 
329 	/* Adjustment value scaled by 2^16 million */
330 	adj = (s64)scaled_ppm * phc->init_cc_mult;
331 
332 	/* Adjustment value to scale */
333 	adj /= (s64)SCALED_PPM;
334 
335 	/* Final adjusted multiplier */
336 	adj += phc->init_cc_mult;
337 
338 	spin_lock_irqsave(&phc->lock, irqflags);
339 
340 	/* update the point-in-time basis to now, before adjusting the rate */
341 	timecounter_read(&phc->tc);
342 	phc->cc.mult = adj;
343 
344 	/* Setphc commands are posted in-order, sequenced by phc->lock.  We
345 	 * need to drop the lock before waiting for the command to complete.
346 	 */
347 	err = ionic_setphc_cmd(phc, &ctx);
348 
349 	spin_unlock_irqrestore(&phc->lock, irqflags);
350 
351 	return ionic_adminq_wait(phc->lif, &ctx, err, true);
352 }
353 
ionic_phc_adjtime(struct ptp_clock_info * info,s64 delta)354 static int ionic_phc_adjtime(struct ptp_clock_info *info, s64 delta)
355 {
356 	struct ionic_phc *phc = container_of(info, struct ionic_phc, ptp_info);
357 	struct ionic_admin_ctx ctx = {};
358 	unsigned long irqflags;
359 	int err;
360 
361 	/* Reject phc adjustments during device upgrade */
362 	if (test_bit(IONIC_LIF_F_FW_RESET, phc->lif->state))
363 		return -EBUSY;
364 
365 	spin_lock_irqsave(&phc->lock, irqflags);
366 
367 	timecounter_adjtime(&phc->tc, delta);
368 
369 	/* Setphc commands are posted in-order, sequenced by phc->lock.  We
370 	 * need to drop the lock before waiting for the command to complete.
371 	 */
372 	err = ionic_setphc_cmd(phc, &ctx);
373 
374 	spin_unlock_irqrestore(&phc->lock, irqflags);
375 
376 	return ionic_adminq_wait(phc->lif, &ctx, err, true);
377 }
378 
ionic_phc_settime64(struct ptp_clock_info * info,const struct timespec64 * ts)379 static int ionic_phc_settime64(struct ptp_clock_info *info,
380 			       const struct timespec64 *ts)
381 {
382 	struct ionic_phc *phc = container_of(info, struct ionic_phc, ptp_info);
383 	struct ionic_admin_ctx ctx = {};
384 	unsigned long irqflags;
385 	int err;
386 	u64 ns;
387 
388 	/* Reject phc adjustments during device upgrade */
389 	if (test_bit(IONIC_LIF_F_FW_RESET, phc->lif->state))
390 		return -EBUSY;
391 
392 	ns = timespec64_to_ns(ts);
393 
394 	spin_lock_irqsave(&phc->lock, irqflags);
395 
396 	timecounter_init(&phc->tc, &phc->cc, ns);
397 
398 	/* Setphc commands are posted in-order, sequenced by phc->lock.  We
399 	 * need to drop the lock before waiting for the command to complete.
400 	 */
401 	err = ionic_setphc_cmd(phc, &ctx);
402 
403 	spin_unlock_irqrestore(&phc->lock, irqflags);
404 
405 	return ionic_adminq_wait(phc->lif, &ctx, err, true);
406 }
407 
ionic_phc_gettimex64(struct ptp_clock_info * info,struct timespec64 * ts,struct ptp_system_timestamp * sts)408 static int ionic_phc_gettimex64(struct ptp_clock_info *info,
409 				struct timespec64 *ts,
410 				struct ptp_system_timestamp *sts)
411 {
412 	struct ionic_phc *phc = container_of(info, struct ionic_phc, ptp_info);
413 	struct ionic *ionic = phc->lif->ionic;
414 	unsigned long irqflags;
415 	u64 tick, ns;
416 
417 	/* Do not attempt to read device time during upgrade */
418 	if (test_bit(IONIC_LIF_F_FW_RESET, phc->lif->state))
419 		return -EBUSY;
420 
421 	spin_lock_irqsave(&phc->lock, irqflags);
422 
423 	tick = ionic_hwstamp_read(ionic, sts);
424 
425 	ns = timecounter_cyc2time(&phc->tc, tick);
426 
427 	spin_unlock_irqrestore(&phc->lock, irqflags);
428 
429 	*ts = ns_to_timespec64(ns);
430 
431 	return 0;
432 }
433 
ionic_phc_aux_work(struct ptp_clock_info * info)434 static long ionic_phc_aux_work(struct ptp_clock_info *info)
435 {
436 	struct ionic_phc *phc = container_of(info, struct ionic_phc, ptp_info);
437 	struct ionic_admin_ctx ctx = {};
438 	unsigned long irqflags;
439 	int err;
440 
441 	/* Do not update phc during device upgrade, but keep polling to resume
442 	 * after upgrade.  Since we don't update the point in time basis, there
443 	 * is no expectation that we are maintaining the phc time during the
444 	 * upgrade.  After upgrade, it will need to be readjusted back to the
445 	 * correct time by the ptp daemon.
446 	 */
447 	if (test_bit(IONIC_LIF_F_FW_RESET, phc->lif->state))
448 		return phc->aux_work_delay;
449 
450 	spin_lock_irqsave(&phc->lock, irqflags);
451 
452 	/* update point-in-time basis to now */
453 	timecounter_read(&phc->tc);
454 
455 	/* Setphc commands are posted in-order, sequenced by phc->lock.  We
456 	 * need to drop the lock before waiting for the command to complete.
457 	 */
458 	err = ionic_setphc_cmd(phc, &ctx);
459 
460 	spin_unlock_irqrestore(&phc->lock, irqflags);
461 
462 	ionic_adminq_wait(phc->lif, &ctx, err, true);
463 
464 	return phc->aux_work_delay;
465 }
466 
ionic_lif_phc_ktime(struct ionic_lif * lif,u64 tick)467 ktime_t ionic_lif_phc_ktime(struct ionic_lif *lif, u64 tick)
468 {
469 	unsigned long irqflags;
470 	u64 ns;
471 
472 	if (!lif->phc)
473 		return 0;
474 
475 	spin_lock_irqsave(&lif->phc->lock, irqflags);
476 	ns = timecounter_cyc2time(&lif->phc->tc, tick);
477 	spin_unlock_irqrestore(&lif->phc->lock, irqflags);
478 
479 	return ns_to_ktime(ns);
480 }
481 
482 static const struct ptp_clock_info ionic_ptp_info = {
483 	.owner		= THIS_MODULE,
484 	.name		= "ionic_ptp",
485 	.adjfine	= ionic_phc_adjfine,
486 	.adjtime	= ionic_phc_adjtime,
487 	.gettimex64	= ionic_phc_gettimex64,
488 	.settime64	= ionic_phc_settime64,
489 	.do_aux_work	= ionic_phc_aux_work,
490 };
491 
ionic_lif_register_phc(struct ionic_lif * lif)492 void ionic_lif_register_phc(struct ionic_lif *lif)
493 {
494 	if (!lif->phc || !(lif->hw_features & IONIC_ETH_HW_TIMESTAMP))
495 		return;
496 
497 	lif->phc->ptp = ptp_clock_register(&lif->phc->ptp_info, lif->ionic->dev);
498 
499 	if (IS_ERR(lif->phc->ptp)) {
500 		dev_warn(lif->ionic->dev, "Cannot register phc device: %ld\n",
501 			 PTR_ERR(lif->phc->ptp));
502 
503 		lif->phc->ptp = NULL;
504 	}
505 
506 	if (lif->phc->ptp)
507 		ptp_schedule_worker(lif->phc->ptp, lif->phc->aux_work_delay);
508 }
509 
ionic_lif_unregister_phc(struct ionic_lif * lif)510 void ionic_lif_unregister_phc(struct ionic_lif *lif)
511 {
512 	if (!lif->phc || !lif->phc->ptp)
513 		return;
514 
515 	ptp_clock_unregister(lif->phc->ptp);
516 
517 	lif->phc->ptp = NULL;
518 }
519 
ionic_lif_alloc_phc(struct ionic_lif * lif)520 void ionic_lif_alloc_phc(struct ionic_lif *lif)
521 {
522 	struct ionic *ionic = lif->ionic;
523 	struct ionic_phc *phc;
524 	u64 delay, diff, mult;
525 	u64 frac = 0;
526 	u64 features;
527 	u32 shift;
528 
529 	if (!ionic->idev.hwstamp_regs)
530 		return;
531 
532 	features = le64_to_cpu(ionic->ident.lif.eth.config.features);
533 	if (!(features & IONIC_ETH_HW_TIMESTAMP))
534 		return;
535 
536 	phc = devm_kzalloc(ionic->dev, sizeof(*phc), GFP_KERNEL);
537 	if (!phc)
538 		return;
539 
540 	phc->lif = lif;
541 
542 	phc->cc.read = ionic_cc_read;
543 	phc->cc.mask = le64_to_cpu(ionic->ident.dev.hwstamp_mask);
544 	phc->cc.mult = le32_to_cpu(ionic->ident.dev.hwstamp_mult);
545 	phc->cc.shift = le32_to_cpu(ionic->ident.dev.hwstamp_shift);
546 
547 	if (!phc->cc.mult) {
548 		dev_err(lif->ionic->dev,
549 			"Invalid device PHC mask multiplier %u, disabling HW timestamp support\n",
550 			phc->cc.mult);
551 		devm_kfree(lif->ionic->dev, phc);
552 		lif->phc = NULL;
553 		return;
554 	}
555 
556 	dev_dbg(lif->ionic->dev, "Device PHC mask %#llx mult %u shift %u\n",
557 		phc->cc.mask, phc->cc.mult, phc->cc.shift);
558 
559 	spin_lock_init(&phc->lock);
560 	mutex_init(&phc->config_lock);
561 
562 	/* max ticks is limited by the multiplier, or by the update period. */
563 	if (phc->cc.shift + 2 + ilog2(IONIC_PHC_UPDATE_NS) >= 64) {
564 		/* max ticks that do not overflow when multiplied by max
565 		 * adjusted multiplier (twice the initial multiplier)
566 		 */
567 		diff = U64_MAX / phc->cc.mult / 2;
568 	} else {
569 		/* approx ticks at four times the update period */
570 		diff = (u64)IONIC_PHC_UPDATE_NS << (phc->cc.shift + 2);
571 		diff = DIV_ROUND_UP(diff, phc->cc.mult);
572 	}
573 
574 	/* transform to bitmask */
575 	diff |= diff >> 1;
576 	diff |= diff >> 2;
577 	diff |= diff >> 4;
578 	diff |= diff >> 8;
579 	diff |= diff >> 16;
580 	diff |= diff >> 32;
581 
582 	/* constrain to the hardware bitmask */
583 	diff &= phc->cc.mask;
584 
585 	/* the wrap period is now defined by diff
586 	 *
587 	 * we will update the time basis at about 1/4 the wrap period, so
588 	 * should not see a difference of more than +/- diff/4.
589 	 *
590 	 * this is sufficient not see a difference of more than +/- diff/2, as
591 	 * required by timecounter_cyc2time, to detect an old time stamp.
592 	 *
593 	 * adjust the initial multiplier, being careful to avoid overflow:
594 	 *  - do not overflow 63 bits: init_cc_mult * SCALED_PPM
595 	 *  - do not overflow 64 bits: max_mult * (diff / 2)
596 	 *
597 	 * we want to increase the initial multiplier as much as possible, to
598 	 * allow for more precise adjustment in ionic_phc_adjfine.
599 	 *
600 	 * only adjust the multiplier if we can double it or more.
601 	 */
602 	mult = U64_MAX / 2 / max(diff / 2, SCALED_PPM);
603 	shift = mult / phc->cc.mult;
604 	if (shift >= 2) {
605 		/* initial multiplier will be 2^n of hardware cc.mult */
606 		shift = fls(shift);
607 		/* increase cc.mult and cc.shift by the same 2^n and n. */
608 		phc->cc.mult <<= shift;
609 		phc->cc.shift += shift;
610 	}
611 
612 	dev_dbg(lif->ionic->dev, "Initial PHC mask %#llx mult %u shift %u\n",
613 		phc->cc.mask, phc->cc.mult, phc->cc.shift);
614 
615 	/* frequency adjustments are relative to the initial multiplier */
616 	phc->init_cc_mult = phc->cc.mult;
617 
618 	timecounter_init(&phc->tc, &phc->cc, ktime_get_real_ns());
619 
620 	/* Update cycle_last at 1/4 the wrap period, or IONIC_PHC_UPDATE_NS */
621 	delay = min_t(u64, IONIC_PHC_UPDATE_NS,
622 		      cyclecounter_cyc2ns(&phc->cc, diff / 4, 0, &frac));
623 	dev_dbg(lif->ionic->dev, "Work delay %llu ms\n", delay / NSEC_PER_MSEC);
624 
625 	phc->aux_work_delay = nsecs_to_jiffies(delay);
626 
627 	phc->ptp_info = ionic_ptp_info;
628 
629 	/* We have allowed to adjust the multiplier up to +/- 1 part per 1.
630 	 * Here expressed as NORMAL_PPB (1 billion parts per billion).
631 	 */
632 	phc->ptp_info.max_adj = NORMAL_PPB;
633 
634 	lif->phc = phc;
635 }
636 
ionic_lif_free_phc(struct ionic_lif * lif)637 void ionic_lif_free_phc(struct ionic_lif *lif)
638 {
639 	if (!lif->phc)
640 		return;
641 
642 	mutex_destroy(&lif->phc->config_lock);
643 
644 	devm_kfree(lif->ionic->dev, lif->phc);
645 	lif->phc = NULL;
646 }
647