xref: /linux/drivers/net/wireless/mediatek/mt76/tx.c (revision a5d9265e017f081f0dc133c0e2f45103d027b874)
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 	if (pktid == MT_PACKET_ID_NO_ACK)
209 		return NULL;
210 
211 	skb_queue_walk_safe(&dev->status_list, skb, tmp) {
212 		struct mt76_tx_cb *cb = mt76_tx_skb_cb(skb);
213 
214 		if (wcid && cb->wcid != wcid->idx)
215 			continue;
216 
217 		if (cb->pktid == pktid)
218 			return skb;
219 
220 		if (!pktid &&
221 		    !time_after(jiffies, cb->jiffies + MT_TX_STATUS_SKB_TIMEOUT))
222 			continue;
223 
224 		__mt76_tx_status_skb_done(dev, skb, MT_TX_CB_TXS_FAILED |
225 						    MT_TX_CB_TXS_DONE, list);
226 	}
227 
228 	return NULL;
229 }
230 EXPORT_SYMBOL_GPL(mt76_tx_status_skb_get);
231 
232 void
233 mt76_tx_status_check(struct mt76_dev *dev, struct mt76_wcid *wcid, bool flush)
234 {
235 	struct sk_buff_head list;
236 
237 	mt76_tx_status_lock(dev, &list);
238 	mt76_tx_status_skb_get(dev, wcid, flush ? -1 : 0, &list);
239 	mt76_tx_status_unlock(dev, &list);
240 }
241 EXPORT_SYMBOL_GPL(mt76_tx_status_check);
242 
243 void mt76_tx_complete_skb(struct mt76_dev *dev, struct sk_buff *skb)
244 {
245 	struct sk_buff_head list;
246 
247 	if (!skb->prev) {
248 		ieee80211_free_txskb(dev->hw, skb);
249 		return;
250 	}
251 
252 	mt76_tx_status_lock(dev, &list);
253 	__mt76_tx_status_skb_done(dev, skb, MT_TX_CB_DMA_DONE, &list);
254 	mt76_tx_status_unlock(dev, &list);
255 }
256 EXPORT_SYMBOL_GPL(mt76_tx_complete_skb);
257 
258 void
259 mt76_tx(struct mt76_dev *dev, struct ieee80211_sta *sta,
260 	struct mt76_wcid *wcid, struct sk_buff *skb)
261 {
262 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
263 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
264 	struct mt76_queue *q;
265 	int qid = skb_get_queue_mapping(skb);
266 
267 	if (WARN_ON(qid >= MT_TXQ_PSD)) {
268 		qid = MT_TXQ_BE;
269 		skb_set_queue_mapping(skb, qid);
270 	}
271 
272 	if (!wcid->tx_rate_set)
273 		ieee80211_get_tx_rates(info->control.vif, sta, skb,
274 				       info->control.rates, 1);
275 
276 	if (sta && ieee80211_is_data_qos(hdr->frame_control)) {
277 		struct ieee80211_txq *txq;
278 		struct mt76_txq *mtxq;
279 		u8 tid;
280 
281 		tid = skb->priority & IEEE80211_QOS_CTL_TID_MASK;
282 		txq = sta->txq[tid];
283 		mtxq = (struct mt76_txq *) txq->drv_priv;
284 
285 		if (mtxq->aggr)
286 			mt76_check_agg_ssn(mtxq, skb);
287 	}
288 
289 	q = &dev->q_tx[qid];
290 
291 	spin_lock_bh(&q->lock);
292 	dev->queue_ops->tx_queue_skb(dev, q, skb, wcid, sta);
293 	dev->queue_ops->kick(dev, q);
294 
295 	if (q->queued > q->ndesc - 8)
296 		ieee80211_stop_queue(dev->hw, skb_get_queue_mapping(skb));
297 	spin_unlock_bh(&q->lock);
298 }
299 EXPORT_SYMBOL_GPL(mt76_tx);
300 
301 static struct sk_buff *
302 mt76_txq_dequeue(struct mt76_dev *dev, struct mt76_txq *mtxq, bool ps)
303 {
304 	struct ieee80211_txq *txq = mtxq_to_txq(mtxq);
305 	struct sk_buff *skb;
306 
307 	skb = skb_dequeue(&mtxq->retry_q);
308 	if (skb) {
309 		u8 tid = skb->priority & IEEE80211_QOS_CTL_TID_MASK;
310 
311 		if (ps && skb_queue_empty(&mtxq->retry_q))
312 			ieee80211_sta_set_buffered(txq->sta, tid, false);
313 
314 		return skb;
315 	}
316 
317 	skb = ieee80211_tx_dequeue(dev->hw, txq);
318 	if (!skb)
319 		return NULL;
320 
321 	return skb;
322 }
323 
324 static void
325 mt76_queue_ps_skb(struct mt76_dev *dev, struct ieee80211_sta *sta,
326 		  struct sk_buff *skb, bool last)
327 {
328 	struct mt76_wcid *wcid = (struct mt76_wcid *) sta->drv_priv;
329 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
330 	struct mt76_queue *hwq = &dev->q_tx[MT_TXQ_PSD];
331 
332 	info->control.flags |= IEEE80211_TX_CTRL_PS_RESPONSE;
333 	if (last)
334 		info->flags |= IEEE80211_TX_STATUS_EOSP |
335 			       IEEE80211_TX_CTL_REQ_TX_STATUS;
336 
337 	mt76_skb_set_moredata(skb, !last);
338 	dev->queue_ops->tx_queue_skb(dev, hwq, skb, wcid, sta);
339 }
340 
341 void
342 mt76_release_buffered_frames(struct ieee80211_hw *hw, struct ieee80211_sta *sta,
343 			     u16 tids, int nframes,
344 			     enum ieee80211_frame_release_type reason,
345 			     bool more_data)
346 {
347 	struct mt76_dev *dev = hw->priv;
348 	struct sk_buff *last_skb = NULL;
349 	struct mt76_queue *hwq = &dev->q_tx[MT_TXQ_PSD];
350 	int i;
351 
352 	spin_lock_bh(&hwq->lock);
353 	for (i = 0; tids && nframes; i++, tids >>= 1) {
354 		struct ieee80211_txq *txq = sta->txq[i];
355 		struct mt76_txq *mtxq = (struct mt76_txq *) txq->drv_priv;
356 		struct sk_buff *skb;
357 
358 		if (!(tids & 1))
359 			continue;
360 
361 		do {
362 			skb = mt76_txq_dequeue(dev, mtxq, true);
363 			if (!skb)
364 				break;
365 
366 			if (mtxq->aggr)
367 				mt76_check_agg_ssn(mtxq, skb);
368 
369 			nframes--;
370 			if (last_skb)
371 				mt76_queue_ps_skb(dev, sta, last_skb, false);
372 
373 			last_skb = skb;
374 		} while (nframes);
375 	}
376 
377 	if (last_skb) {
378 		mt76_queue_ps_skb(dev, sta, last_skb, true);
379 		dev->queue_ops->kick(dev, hwq);
380 	}
381 	spin_unlock_bh(&hwq->lock);
382 }
383 EXPORT_SYMBOL_GPL(mt76_release_buffered_frames);
384 
385 static int
386 mt76_txq_send_burst(struct mt76_dev *dev, struct mt76_queue *hwq,
387 		    struct mt76_txq *mtxq, bool *empty)
388 {
389 	struct ieee80211_txq *txq = mtxq_to_txq(mtxq);
390 	struct ieee80211_tx_info *info;
391 	struct mt76_wcid *wcid = mtxq->wcid;
392 	struct sk_buff *skb;
393 	int n_frames = 1, limit;
394 	struct ieee80211_tx_rate tx_rate;
395 	bool ampdu;
396 	bool probe;
397 	int idx;
398 
399 	if (test_bit(MT_WCID_FLAG_PS, &wcid->flags)) {
400 		*empty = true;
401 		return 0;
402 	}
403 
404 	skb = mt76_txq_dequeue(dev, mtxq, false);
405 	if (!skb) {
406 		*empty = true;
407 		return 0;
408 	}
409 
410 	info = IEEE80211_SKB_CB(skb);
411 	if (!wcid->tx_rate_set)
412 		ieee80211_get_tx_rates(txq->vif, txq->sta, skb,
413 				       info->control.rates, 1);
414 	tx_rate = info->control.rates[0];
415 
416 	probe = (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE);
417 	ampdu = IEEE80211_SKB_CB(skb)->flags & IEEE80211_TX_CTL_AMPDU;
418 	limit = ampdu ? 16 : 3;
419 
420 	if (ampdu)
421 		mt76_check_agg_ssn(mtxq, skb);
422 
423 	idx = dev->queue_ops->tx_queue_skb(dev, hwq, skb, wcid, txq->sta);
424 
425 	if (idx < 0)
426 		return idx;
427 
428 	do {
429 		bool cur_ampdu;
430 
431 		if (probe)
432 			break;
433 
434 		if (test_bit(MT76_OFFCHANNEL, &dev->state) ||
435 		    test_bit(MT76_RESET, &dev->state))
436 			return -EBUSY;
437 
438 		skb = mt76_txq_dequeue(dev, mtxq, false);
439 		if (!skb) {
440 			*empty = true;
441 			break;
442 		}
443 
444 		info = IEEE80211_SKB_CB(skb);
445 		cur_ampdu = info->flags & IEEE80211_TX_CTL_AMPDU;
446 
447 		if (ampdu != cur_ampdu ||
448 		    (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)) {
449 			skb_queue_tail(&mtxq->retry_q, skb);
450 			break;
451 		}
452 
453 		info->control.rates[0] = tx_rate;
454 
455 		if (cur_ampdu)
456 			mt76_check_agg_ssn(mtxq, skb);
457 
458 		idx = dev->queue_ops->tx_queue_skb(dev, hwq, skb, wcid,
459 						   txq->sta);
460 		if (idx < 0)
461 			return idx;
462 
463 		n_frames++;
464 	} while (n_frames < limit);
465 
466 	if (!probe) {
467 		hwq->swq_queued++;
468 		hwq->entry[idx].schedule = true;
469 	}
470 
471 	dev->queue_ops->kick(dev, hwq);
472 
473 	return n_frames;
474 }
475 
476 static int
477 mt76_txq_schedule_list(struct mt76_dev *dev, struct mt76_queue *hwq)
478 {
479 	struct mt76_txq *mtxq, *mtxq_last;
480 	int len = 0;
481 
482 restart:
483 	mtxq_last = list_last_entry(&hwq->swq, struct mt76_txq, list);
484 	while (!list_empty(&hwq->swq)) {
485 		bool empty = false;
486 		int cur;
487 
488 		if (test_bit(MT76_OFFCHANNEL, &dev->state) ||
489 		    test_bit(MT76_RESET, &dev->state))
490 			return -EBUSY;
491 
492 		mtxq = list_first_entry(&hwq->swq, struct mt76_txq, list);
493 		if (mtxq->send_bar && mtxq->aggr) {
494 			struct ieee80211_txq *txq = mtxq_to_txq(mtxq);
495 			struct ieee80211_sta *sta = txq->sta;
496 			struct ieee80211_vif *vif = txq->vif;
497 			u16 agg_ssn = mtxq->agg_ssn;
498 			u8 tid = txq->tid;
499 
500 			mtxq->send_bar = false;
501 			spin_unlock_bh(&hwq->lock);
502 			ieee80211_send_bar(vif, sta->addr, tid, agg_ssn);
503 			spin_lock_bh(&hwq->lock);
504 			goto restart;
505 		}
506 
507 		list_del_init(&mtxq->list);
508 
509 		cur = mt76_txq_send_burst(dev, hwq, mtxq, &empty);
510 		if (!empty)
511 			list_add_tail(&mtxq->list, &hwq->swq);
512 
513 		if (cur < 0)
514 			return cur;
515 
516 		len += cur;
517 
518 		if (mtxq == mtxq_last)
519 			break;
520 	}
521 
522 	return len;
523 }
524 
525 void mt76_txq_schedule(struct mt76_dev *dev, struct mt76_queue *hwq)
526 {
527 	int len;
528 
529 	rcu_read_lock();
530 	do {
531 		if (hwq->swq_queued >= 4 || list_empty(&hwq->swq))
532 			break;
533 
534 		len = mt76_txq_schedule_list(dev, hwq);
535 	} while (len > 0);
536 	rcu_read_unlock();
537 }
538 EXPORT_SYMBOL_GPL(mt76_txq_schedule);
539 
540 void mt76_txq_schedule_all(struct mt76_dev *dev)
541 {
542 	int i;
543 
544 	for (i = 0; i <= MT_TXQ_BK; i++) {
545 		struct mt76_queue *q = &dev->q_tx[i];
546 
547 		spin_lock_bh(&q->lock);
548 		mt76_txq_schedule(dev, q);
549 		spin_unlock_bh(&q->lock);
550 	}
551 }
552 EXPORT_SYMBOL_GPL(mt76_txq_schedule_all);
553 
554 void mt76_stop_tx_queues(struct mt76_dev *dev, struct ieee80211_sta *sta,
555 			 bool send_bar)
556 {
557 	int i;
558 
559 	for (i = 0; i < ARRAY_SIZE(sta->txq); i++) {
560 		struct ieee80211_txq *txq = sta->txq[i];
561 		struct mt76_txq *mtxq;
562 
563 		if (!txq)
564 			continue;
565 
566 		mtxq = (struct mt76_txq *)txq->drv_priv;
567 
568 		spin_lock_bh(&mtxq->hwq->lock);
569 		mtxq->send_bar = mtxq->aggr && send_bar;
570 		if (!list_empty(&mtxq->list))
571 			list_del_init(&mtxq->list);
572 		spin_unlock_bh(&mtxq->hwq->lock);
573 	}
574 }
575 EXPORT_SYMBOL_GPL(mt76_stop_tx_queues);
576 
577 void mt76_wake_tx_queue(struct ieee80211_hw *hw, struct ieee80211_txq *txq)
578 {
579 	struct mt76_dev *dev = hw->priv;
580 	struct mt76_txq *mtxq = (struct mt76_txq *) txq->drv_priv;
581 	struct mt76_queue *hwq = mtxq->hwq;
582 
583 	spin_lock_bh(&hwq->lock);
584 	if (list_empty(&mtxq->list))
585 		list_add_tail(&mtxq->list, &hwq->swq);
586 	mt76_txq_schedule(dev, hwq);
587 	spin_unlock_bh(&hwq->lock);
588 }
589 EXPORT_SYMBOL_GPL(mt76_wake_tx_queue);
590 
591 void mt76_txq_remove(struct mt76_dev *dev, struct ieee80211_txq *txq)
592 {
593 	struct mt76_txq *mtxq;
594 	struct mt76_queue *hwq;
595 	struct sk_buff *skb;
596 
597 	if (!txq)
598 		return;
599 
600 	mtxq = (struct mt76_txq *) txq->drv_priv;
601 	hwq = mtxq->hwq;
602 
603 	spin_lock_bh(&hwq->lock);
604 	if (!list_empty(&mtxq->list))
605 		list_del_init(&mtxq->list);
606 	spin_unlock_bh(&hwq->lock);
607 
608 	while ((skb = skb_dequeue(&mtxq->retry_q)) != NULL)
609 		ieee80211_free_txskb(dev->hw, skb);
610 }
611 EXPORT_SYMBOL_GPL(mt76_txq_remove);
612 
613 void mt76_txq_init(struct mt76_dev *dev, struct ieee80211_txq *txq)
614 {
615 	struct mt76_txq *mtxq = (struct mt76_txq *) txq->drv_priv;
616 
617 	INIT_LIST_HEAD(&mtxq->list);
618 	skb_queue_head_init(&mtxq->retry_q);
619 
620 	mtxq->hwq = &dev->q_tx[mt76_txq_get_qid(txq)];
621 }
622 EXPORT_SYMBOL_GPL(mt76_txq_init);
623 
624 u8 mt76_ac_to_hwq(u8 ac)
625 {
626 	static const u8 wmm_queue_map[] = {
627 		[IEEE80211_AC_BE] = 0,
628 		[IEEE80211_AC_BK] = 1,
629 		[IEEE80211_AC_VI] = 2,
630 		[IEEE80211_AC_VO] = 3,
631 	};
632 
633 	if (WARN_ON(ac >= IEEE80211_NUM_ACS))
634 		return 0;
635 
636 	return wmm_queue_map[ac];
637 }
638 EXPORT_SYMBOL_GPL(mt76_ac_to_hwq);
639