1 /*
2  * Copyright (C) 2016 Felix Fietkau <nbd@nbd.name>
3  *
4  * Permission to use, copy, modify, and/or distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include "mt76.h"
18 
19 static struct mt76_txwi_cache *
20 mt76_alloc_txwi(struct mt76_dev *dev)
21 {
22 	struct mt76_txwi_cache *t;
23 	dma_addr_t addr;
24 	int size;
25 
26 	size = (sizeof(*t) + L1_CACHE_BYTES - 1) & ~(L1_CACHE_BYTES - 1);
27 	t = devm_kzalloc(dev->dev, size, GFP_ATOMIC);
28 	if (!t)
29 		return NULL;
30 
31 	addr = dma_map_single(dev->dev, &t->txwi, sizeof(t->txwi),
32 			      DMA_TO_DEVICE);
33 	t->dma_addr = addr;
34 
35 	return t;
36 }
37 
38 static struct mt76_txwi_cache *
39 __mt76_get_txwi(struct mt76_dev *dev)
40 {
41 	struct mt76_txwi_cache *t = NULL;
42 
43 	spin_lock_bh(&dev->lock);
44 	if (!list_empty(&dev->txwi_cache)) {
45 		t = list_first_entry(&dev->txwi_cache, struct mt76_txwi_cache,
46 				     list);
47 		list_del(&t->list);
48 	}
49 	spin_unlock_bh(&dev->lock);
50 
51 	return t;
52 }
53 
54 struct mt76_txwi_cache *
55 mt76_get_txwi(struct mt76_dev *dev)
56 {
57 	struct mt76_txwi_cache *t = __mt76_get_txwi(dev);
58 
59 	if (t)
60 		return t;
61 
62 	return mt76_alloc_txwi(dev);
63 }
64 
65 void
66 mt76_put_txwi(struct mt76_dev *dev, struct mt76_txwi_cache *t)
67 {
68 	if (!t)
69 		return;
70 
71 	spin_lock_bh(&dev->lock);
72 	list_add(&t->list, &dev->txwi_cache);
73 	spin_unlock_bh(&dev->lock);
74 }
75 
76 void mt76_tx_free(struct mt76_dev *dev)
77 {
78 	struct mt76_txwi_cache *t;
79 
80 	while ((t = __mt76_get_txwi(dev)) != NULL)
81 		dma_unmap_single(dev->dev, t->dma_addr, sizeof(t->txwi),
82 				 DMA_TO_DEVICE);
83 }
84 
85 static int
86 mt76_txq_get_qid(struct ieee80211_txq *txq)
87 {
88 	if (!txq->sta)
89 		return MT_TXQ_BE;
90 
91 	return txq->ac;
92 }
93 
94 static void
95 mt76_check_agg_ssn(struct mt76_txq *mtxq, struct sk_buff *skb)
96 {
97 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
98 
99 	if (!ieee80211_is_data_qos(hdr->frame_control) ||
100 	    !ieee80211_is_data_present(hdr->frame_control))
101 		return;
102 
103 	mtxq->agg_ssn = le16_to_cpu(hdr->seq_ctrl) + 0x10;
104 }
105 
106 void
107 mt76_tx_status_lock(struct mt76_dev *dev, struct sk_buff_head *list)
108 		   __acquires(&dev->status_list.lock)
109 {
110 	__skb_queue_head_init(list);
111 	spin_lock_bh(&dev->status_list.lock);
112 	__acquire(&dev->status_list.lock);
113 }
114 EXPORT_SYMBOL_GPL(mt76_tx_status_lock);
115 
116 void
117 mt76_tx_status_unlock(struct mt76_dev *dev, struct sk_buff_head *list)
118 		      __releases(&dev->status_list.unlock)
119 {
120 	struct sk_buff *skb;
121 
122 	spin_unlock_bh(&dev->status_list.lock);
123 	__release(&dev->status_list.unlock);
124 
125 	while ((skb = __skb_dequeue(list)) != NULL)
126 		ieee80211_tx_status(dev->hw, skb);
127 }
128 EXPORT_SYMBOL_GPL(mt76_tx_status_unlock);
129 
130 static void
131 __mt76_tx_status_skb_done(struct mt76_dev *dev, struct sk_buff *skb, u8 flags,
132 			  struct sk_buff_head *list)
133 {
134 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
135 	struct mt76_tx_cb *cb = mt76_tx_skb_cb(skb);
136 	u8 done = MT_TX_CB_DMA_DONE | MT_TX_CB_TXS_DONE;
137 
138 	flags |= cb->flags;
139 	cb->flags = flags;
140 
141 	if ((flags & done) != done)
142 		return;
143 
144 	__skb_unlink(skb, &dev->status_list);
145 
146 	/* Tx status can be unreliable. if it fails, mark the frame as ACKed */
147 	if (flags & MT_TX_CB_TXS_FAILED) {
148 		ieee80211_tx_info_clear_status(info);
149 		info->status.rates[0].idx = -1;
150 		info->flags |= IEEE80211_TX_STAT_ACK;
151 	}
152 
153 	__skb_queue_tail(list, skb);
154 }
155 
156 void
157 mt76_tx_status_skb_done(struct mt76_dev *dev, struct sk_buff *skb,
158 			struct sk_buff_head *list)
159 {
160 	__mt76_tx_status_skb_done(dev, skb, MT_TX_CB_TXS_DONE, list);
161 }
162 EXPORT_SYMBOL_GPL(mt76_tx_status_skb_done);
163 
164 int
165 mt76_tx_status_skb_add(struct mt76_dev *dev, struct mt76_wcid *wcid,
166 		       struct sk_buff *skb)
167 {
168 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
169 	struct mt76_tx_cb *cb = mt76_tx_skb_cb(skb);
170 	int pid;
171 
172 	if (!wcid)
173 		return MT_PACKET_ID_NO_ACK;
174 
175 	if (info->flags & IEEE80211_TX_CTL_NO_ACK)
176 		return MT_PACKET_ID_NO_ACK;
177 
178 	if (!(info->flags & (IEEE80211_TX_CTL_REQ_TX_STATUS |
179 			     IEEE80211_TX_CTL_RATE_CTRL_PROBE)))
180 		return MT_PACKET_ID_NO_SKB;
181 
182 	spin_lock_bh(&dev->status_list.lock);
183 
184 	memset(cb, 0, sizeof(*cb));
185 	wcid->packet_id = (wcid->packet_id + 1) & MT_PACKET_ID_MASK;
186 	if (wcid->packet_id == MT_PACKET_ID_NO_ACK ||
187 	    wcid->packet_id == MT_PACKET_ID_NO_SKB)
188 		wcid->packet_id = MT_PACKET_ID_FIRST;
189 
190 	pid = wcid->packet_id;
191 	cb->wcid = wcid->idx;
192 	cb->pktid = pid;
193 	cb->jiffies = jiffies;
194 
195 	__skb_queue_tail(&dev->status_list, skb);
196 	spin_unlock_bh(&dev->status_list.lock);
197 
198 	return pid;
199 }
200 EXPORT_SYMBOL_GPL(mt76_tx_status_skb_add);
201 
202 struct sk_buff *
203 mt76_tx_status_skb_get(struct mt76_dev *dev, struct mt76_wcid *wcid, int pktid,
204 		       struct sk_buff_head *list)
205 {
206 	struct sk_buff *skb, *tmp;
207 
208 	skb_queue_walk_safe(&dev->status_list, skb, tmp) {
209 		struct mt76_tx_cb *cb = mt76_tx_skb_cb(skb);
210 
211 		if (wcid && cb->wcid != wcid->idx)
212 			continue;
213 
214 		if (cb->pktid == pktid)
215 			return skb;
216 
217 		if (pktid >= 0 &&
218 		    !time_after(jiffies, cb->jiffies + MT_TX_STATUS_SKB_TIMEOUT))
219 			continue;
220 
221 		__mt76_tx_status_skb_done(dev, skb, MT_TX_CB_TXS_FAILED |
222 						    MT_TX_CB_TXS_DONE, list);
223 	}
224 
225 	return NULL;
226 }
227 EXPORT_SYMBOL_GPL(mt76_tx_status_skb_get);
228 
229 void
230 mt76_tx_status_check(struct mt76_dev *dev, struct mt76_wcid *wcid, bool flush)
231 {
232 	struct sk_buff_head list;
233 
234 	mt76_tx_status_lock(dev, &list);
235 	mt76_tx_status_skb_get(dev, wcid, flush ? -1 : 0, &list);
236 	mt76_tx_status_unlock(dev, &list);
237 }
238 EXPORT_SYMBOL_GPL(mt76_tx_status_check);
239 
240 void mt76_tx_complete_skb(struct mt76_dev *dev, struct sk_buff *skb)
241 {
242 	struct sk_buff_head list;
243 
244 	if (!skb->prev) {
245 		ieee80211_free_txskb(dev->hw, skb);
246 		return;
247 	}
248 
249 	mt76_tx_status_lock(dev, &list);
250 	__mt76_tx_status_skb_done(dev, skb, MT_TX_CB_DMA_DONE, &list);
251 	mt76_tx_status_unlock(dev, &list);
252 }
253 EXPORT_SYMBOL_GPL(mt76_tx_complete_skb);
254 
255 void
256 mt76_tx(struct mt76_dev *dev, struct ieee80211_sta *sta,
257 	struct mt76_wcid *wcid, struct sk_buff *skb)
258 {
259 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
260 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
261 	struct mt76_queue *q;
262 	int qid = skb_get_queue_mapping(skb);
263 
264 	if (WARN_ON(qid >= MT_TXQ_PSD)) {
265 		qid = MT_TXQ_BE;
266 		skb_set_queue_mapping(skb, qid);
267 	}
268 
269 	if (!wcid->tx_rate_set)
270 		ieee80211_get_tx_rates(info->control.vif, sta, skb,
271 				       info->control.rates, 1);
272 
273 	if (sta && ieee80211_is_data_qos(hdr->frame_control)) {
274 		struct ieee80211_txq *txq;
275 		struct mt76_txq *mtxq;
276 		u8 tid;
277 
278 		tid = skb->priority & IEEE80211_QOS_CTL_TID_MASK;
279 		txq = sta->txq[tid];
280 		mtxq = (struct mt76_txq *) txq->drv_priv;
281 
282 		if (mtxq->aggr)
283 			mt76_check_agg_ssn(mtxq, skb);
284 	}
285 
286 	q = &dev->q_tx[qid];
287 
288 	spin_lock_bh(&q->lock);
289 	dev->queue_ops->tx_queue_skb(dev, q, skb, wcid, sta);
290 	dev->queue_ops->kick(dev, q);
291 
292 	if (q->queued > q->ndesc - 8)
293 		ieee80211_stop_queue(dev->hw, skb_get_queue_mapping(skb));
294 	spin_unlock_bh(&q->lock);
295 }
296 EXPORT_SYMBOL_GPL(mt76_tx);
297 
298 static struct sk_buff *
299 mt76_txq_dequeue(struct mt76_dev *dev, struct mt76_txq *mtxq, bool ps)
300 {
301 	struct ieee80211_txq *txq = mtxq_to_txq(mtxq);
302 	struct sk_buff *skb;
303 
304 	skb = skb_dequeue(&mtxq->retry_q);
305 	if (skb) {
306 		u8 tid = skb->priority & IEEE80211_QOS_CTL_TID_MASK;
307 
308 		if (ps && skb_queue_empty(&mtxq->retry_q))
309 			ieee80211_sta_set_buffered(txq->sta, tid, false);
310 
311 		return skb;
312 	}
313 
314 	skb = ieee80211_tx_dequeue(dev->hw, txq);
315 	if (!skb)
316 		return NULL;
317 
318 	return skb;
319 }
320 
321 static void
322 mt76_queue_ps_skb(struct mt76_dev *dev, struct ieee80211_sta *sta,
323 		  struct sk_buff *skb, bool last)
324 {
325 	struct mt76_wcid *wcid = (struct mt76_wcid *) sta->drv_priv;
326 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
327 	struct mt76_queue *hwq = &dev->q_tx[MT_TXQ_PSD];
328 
329 	info->control.flags |= IEEE80211_TX_CTRL_PS_RESPONSE;
330 	if (last)
331 		info->flags |= IEEE80211_TX_STATUS_EOSP |
332 			       IEEE80211_TX_CTL_REQ_TX_STATUS;
333 
334 	mt76_skb_set_moredata(skb, !last);
335 	dev->queue_ops->tx_queue_skb(dev, hwq, skb, wcid, sta);
336 }
337 
338 void
339 mt76_release_buffered_frames(struct ieee80211_hw *hw, struct ieee80211_sta *sta,
340 			     u16 tids, int nframes,
341 			     enum ieee80211_frame_release_type reason,
342 			     bool more_data)
343 {
344 	struct mt76_dev *dev = hw->priv;
345 	struct sk_buff *last_skb = NULL;
346 	struct mt76_queue *hwq = &dev->q_tx[MT_TXQ_PSD];
347 	int i;
348 
349 	spin_lock_bh(&hwq->lock);
350 	for (i = 0; tids && nframes; i++, tids >>= 1) {
351 		struct ieee80211_txq *txq = sta->txq[i];
352 		struct mt76_txq *mtxq = (struct mt76_txq *) txq->drv_priv;
353 		struct sk_buff *skb;
354 
355 		if (!(tids & 1))
356 			continue;
357 
358 		do {
359 			skb = mt76_txq_dequeue(dev, mtxq, true);
360 			if (!skb)
361 				break;
362 
363 			if (mtxq->aggr)
364 				mt76_check_agg_ssn(mtxq, skb);
365 
366 			nframes--;
367 			if (last_skb)
368 				mt76_queue_ps_skb(dev, sta, last_skb, false);
369 
370 			last_skb = skb;
371 		} while (nframes);
372 	}
373 
374 	if (last_skb) {
375 		mt76_queue_ps_skb(dev, sta, last_skb, true);
376 		dev->queue_ops->kick(dev, hwq);
377 	}
378 	spin_unlock_bh(&hwq->lock);
379 }
380 EXPORT_SYMBOL_GPL(mt76_release_buffered_frames);
381 
382 static int
383 mt76_txq_send_burst(struct mt76_dev *dev, struct mt76_queue *hwq,
384 		    struct mt76_txq *mtxq, bool *empty)
385 {
386 	struct ieee80211_txq *txq = mtxq_to_txq(mtxq);
387 	struct ieee80211_tx_info *info;
388 	struct mt76_wcid *wcid = mtxq->wcid;
389 	struct sk_buff *skb;
390 	int n_frames = 1, limit;
391 	struct ieee80211_tx_rate tx_rate;
392 	bool ampdu;
393 	bool probe;
394 	int idx;
395 
396 	if (test_bit(MT_WCID_FLAG_PS, &wcid->flags)) {
397 		*empty = true;
398 		return 0;
399 	}
400 
401 	skb = mt76_txq_dequeue(dev, mtxq, false);
402 	if (!skb) {
403 		*empty = true;
404 		return 0;
405 	}
406 
407 	info = IEEE80211_SKB_CB(skb);
408 	if (!wcid->tx_rate_set)
409 		ieee80211_get_tx_rates(txq->vif, txq->sta, skb,
410 				       info->control.rates, 1);
411 	tx_rate = info->control.rates[0];
412 
413 	probe = (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE);
414 	ampdu = IEEE80211_SKB_CB(skb)->flags & IEEE80211_TX_CTL_AMPDU;
415 	limit = ampdu ? 16 : 3;
416 
417 	if (ampdu)
418 		mt76_check_agg_ssn(mtxq, skb);
419 
420 	idx = dev->queue_ops->tx_queue_skb(dev, hwq, skb, wcid, txq->sta);
421 
422 	if (idx < 0)
423 		return idx;
424 
425 	do {
426 		bool cur_ampdu;
427 
428 		if (probe)
429 			break;
430 
431 		if (test_bit(MT76_OFFCHANNEL, &dev->state) ||
432 		    test_bit(MT76_RESET, &dev->state))
433 			return -EBUSY;
434 
435 		skb = mt76_txq_dequeue(dev, mtxq, false);
436 		if (!skb) {
437 			*empty = true;
438 			break;
439 		}
440 
441 		info = IEEE80211_SKB_CB(skb);
442 		cur_ampdu = info->flags & IEEE80211_TX_CTL_AMPDU;
443 
444 		if (ampdu != cur_ampdu ||
445 		    (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)) {
446 			skb_queue_tail(&mtxq->retry_q, skb);
447 			break;
448 		}
449 
450 		info->control.rates[0] = tx_rate;
451 
452 		if (cur_ampdu)
453 			mt76_check_agg_ssn(mtxq, skb);
454 
455 		idx = dev->queue_ops->tx_queue_skb(dev, hwq, skb, wcid,
456 						   txq->sta);
457 		if (idx < 0)
458 			return idx;
459 
460 		n_frames++;
461 	} while (n_frames < limit);
462 
463 	if (!probe) {
464 		hwq->swq_queued++;
465 		hwq->entry[idx].schedule = true;
466 	}
467 
468 	dev->queue_ops->kick(dev, hwq);
469 
470 	return n_frames;
471 }
472 
473 static int
474 mt76_txq_schedule_list(struct mt76_dev *dev, struct mt76_queue *hwq)
475 {
476 	struct mt76_txq *mtxq, *mtxq_last;
477 	int len = 0;
478 
479 restart:
480 	mtxq_last = list_last_entry(&hwq->swq, struct mt76_txq, list);
481 	while (!list_empty(&hwq->swq)) {
482 		bool empty = false;
483 		int cur;
484 
485 		if (test_bit(MT76_OFFCHANNEL, &dev->state) ||
486 		    test_bit(MT76_RESET, &dev->state))
487 			return -EBUSY;
488 
489 		mtxq = list_first_entry(&hwq->swq, struct mt76_txq, list);
490 		if (mtxq->send_bar && mtxq->aggr) {
491 			struct ieee80211_txq *txq = mtxq_to_txq(mtxq);
492 			struct ieee80211_sta *sta = txq->sta;
493 			struct ieee80211_vif *vif = txq->vif;
494 			u16 agg_ssn = mtxq->agg_ssn;
495 			u8 tid = txq->tid;
496 
497 			mtxq->send_bar = false;
498 			spin_unlock_bh(&hwq->lock);
499 			ieee80211_send_bar(vif, sta->addr, tid, agg_ssn);
500 			spin_lock_bh(&hwq->lock);
501 			goto restart;
502 		}
503 
504 		list_del_init(&mtxq->list);
505 
506 		cur = mt76_txq_send_burst(dev, hwq, mtxq, &empty);
507 		if (!empty)
508 			list_add_tail(&mtxq->list, &hwq->swq);
509 
510 		if (cur < 0)
511 			return cur;
512 
513 		len += cur;
514 
515 		if (mtxq == mtxq_last)
516 			break;
517 	}
518 
519 	return len;
520 }
521 
522 void mt76_txq_schedule(struct mt76_dev *dev, struct mt76_queue *hwq)
523 {
524 	int len;
525 
526 	rcu_read_lock();
527 	do {
528 		if (hwq->swq_queued >= 4 || list_empty(&hwq->swq))
529 			break;
530 
531 		len = mt76_txq_schedule_list(dev, hwq);
532 	} while (len > 0);
533 	rcu_read_unlock();
534 }
535 EXPORT_SYMBOL_GPL(mt76_txq_schedule);
536 
537 void mt76_txq_schedule_all(struct mt76_dev *dev)
538 {
539 	int i;
540 
541 	for (i = 0; i <= MT_TXQ_BK; i++) {
542 		struct mt76_queue *q = &dev->q_tx[i];
543 
544 		spin_lock_bh(&q->lock);
545 		mt76_txq_schedule(dev, q);
546 		spin_unlock_bh(&q->lock);
547 	}
548 }
549 EXPORT_SYMBOL_GPL(mt76_txq_schedule_all);
550 
551 void mt76_stop_tx_queues(struct mt76_dev *dev, struct ieee80211_sta *sta,
552 			 bool send_bar)
553 {
554 	int i;
555 
556 	for (i = 0; i < ARRAY_SIZE(sta->txq); i++) {
557 		struct ieee80211_txq *txq = sta->txq[i];
558 		struct mt76_txq *mtxq;
559 
560 		if (!txq)
561 			continue;
562 
563 		mtxq = (struct mt76_txq *)txq->drv_priv;
564 
565 		spin_lock_bh(&mtxq->hwq->lock);
566 		mtxq->send_bar = mtxq->aggr && send_bar;
567 		if (!list_empty(&mtxq->list))
568 			list_del_init(&mtxq->list);
569 		spin_unlock_bh(&mtxq->hwq->lock);
570 	}
571 }
572 EXPORT_SYMBOL_GPL(mt76_stop_tx_queues);
573 
574 void mt76_wake_tx_queue(struct ieee80211_hw *hw, struct ieee80211_txq *txq)
575 {
576 	struct mt76_dev *dev = hw->priv;
577 	struct mt76_txq *mtxq = (struct mt76_txq *) txq->drv_priv;
578 	struct mt76_queue *hwq = mtxq->hwq;
579 
580 	spin_lock_bh(&hwq->lock);
581 	if (list_empty(&mtxq->list))
582 		list_add_tail(&mtxq->list, &hwq->swq);
583 	mt76_txq_schedule(dev, hwq);
584 	spin_unlock_bh(&hwq->lock);
585 }
586 EXPORT_SYMBOL_GPL(mt76_wake_tx_queue);
587 
588 void mt76_txq_remove(struct mt76_dev *dev, struct ieee80211_txq *txq)
589 {
590 	struct mt76_txq *mtxq;
591 	struct mt76_queue *hwq;
592 	struct sk_buff *skb;
593 
594 	if (!txq)
595 		return;
596 
597 	mtxq = (struct mt76_txq *) txq->drv_priv;
598 	hwq = mtxq->hwq;
599 
600 	spin_lock_bh(&hwq->lock);
601 	if (!list_empty(&mtxq->list))
602 		list_del_init(&mtxq->list);
603 	spin_unlock_bh(&hwq->lock);
604 
605 	while ((skb = skb_dequeue(&mtxq->retry_q)) != NULL)
606 		ieee80211_free_txskb(dev->hw, skb);
607 }
608 EXPORT_SYMBOL_GPL(mt76_txq_remove);
609 
610 void mt76_txq_init(struct mt76_dev *dev, struct ieee80211_txq *txq)
611 {
612 	struct mt76_txq *mtxq = (struct mt76_txq *) txq->drv_priv;
613 
614 	INIT_LIST_HEAD(&mtxq->list);
615 	skb_queue_head_init(&mtxq->retry_q);
616 
617 	mtxq->hwq = &dev->q_tx[mt76_txq_get_qid(txq)];
618 }
619 EXPORT_SYMBOL_GPL(mt76_txq_init);
620 
621 u8 mt76_ac_to_hwq(u8 ac)
622 {
623 	static const u8 wmm_queue_map[] = {
624 		[IEEE80211_AC_BE] = 0,
625 		[IEEE80211_AC_BK] = 1,
626 		[IEEE80211_AC_VI] = 2,
627 		[IEEE80211_AC_VO] = 3,
628 	};
629 
630 	if (WARN_ON(ac >= IEEE80211_NUM_ACS))
631 		return 0;
632 
633 	return wmm_queue_map[ac];
634 }
635 EXPORT_SYMBOL_GPL(mt76_ac_to_hwq);
636