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 && !q->stopped) {
293 		ieee80211_stop_queue(dev->hw, skb_get_queue_mapping(skb));
294 		q->stopped = true;
295 	}
296 
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 	} else {
381 		ieee80211_sta_eosp(sta);
382 	}
383 
384 	spin_unlock_bh(&hwq->lock);
385 }
386 EXPORT_SYMBOL_GPL(mt76_release_buffered_frames);
387 
388 static int
389 mt76_txq_send_burst(struct mt76_dev *dev, struct mt76_queue *hwq,
390 		    struct mt76_txq *mtxq, bool *empty)
391 {
392 	struct ieee80211_txq *txq = mtxq_to_txq(mtxq);
393 	struct ieee80211_tx_info *info;
394 	struct mt76_wcid *wcid = mtxq->wcid;
395 	struct sk_buff *skb;
396 	int n_frames = 1, limit;
397 	struct ieee80211_tx_rate tx_rate;
398 	bool ampdu;
399 	bool probe;
400 	int idx;
401 
402 	if (test_bit(MT_WCID_FLAG_PS, &wcid->flags)) {
403 		*empty = true;
404 		return 0;
405 	}
406 
407 	skb = mt76_txq_dequeue(dev, mtxq, false);
408 	if (!skb) {
409 		*empty = true;
410 		return 0;
411 	}
412 
413 	info = IEEE80211_SKB_CB(skb);
414 	if (!wcid->tx_rate_set)
415 		ieee80211_get_tx_rates(txq->vif, txq->sta, skb,
416 				       info->control.rates, 1);
417 	tx_rate = info->control.rates[0];
418 
419 	probe = (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE);
420 	ampdu = IEEE80211_SKB_CB(skb)->flags & IEEE80211_TX_CTL_AMPDU;
421 	limit = ampdu ? 16 : 3;
422 
423 	if (ampdu)
424 		mt76_check_agg_ssn(mtxq, skb);
425 
426 	idx = dev->queue_ops->tx_queue_skb(dev, hwq, skb, wcid, txq->sta);
427 
428 	if (idx < 0)
429 		return idx;
430 
431 	do {
432 		bool cur_ampdu;
433 
434 		if (probe)
435 			break;
436 
437 		if (test_bit(MT76_OFFCHANNEL, &dev->state) ||
438 		    test_bit(MT76_RESET, &dev->state))
439 			return -EBUSY;
440 
441 		skb = mt76_txq_dequeue(dev, mtxq, false);
442 		if (!skb) {
443 			*empty = true;
444 			break;
445 		}
446 
447 		info = IEEE80211_SKB_CB(skb);
448 		cur_ampdu = info->flags & IEEE80211_TX_CTL_AMPDU;
449 
450 		if (ampdu != cur_ampdu ||
451 		    (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)) {
452 			skb_queue_tail(&mtxq->retry_q, skb);
453 			break;
454 		}
455 
456 		info->control.rates[0] = tx_rate;
457 
458 		if (cur_ampdu)
459 			mt76_check_agg_ssn(mtxq, skb);
460 
461 		idx = dev->queue_ops->tx_queue_skb(dev, hwq, skb, wcid,
462 						   txq->sta);
463 		if (idx < 0)
464 			return idx;
465 
466 		n_frames++;
467 	} while (n_frames < limit);
468 
469 	if (!probe) {
470 		hwq->swq_queued++;
471 		hwq->entry[idx].schedule = true;
472 	}
473 
474 	dev->queue_ops->kick(dev, hwq);
475 
476 	return n_frames;
477 }
478 
479 static int
480 mt76_txq_schedule_list(struct mt76_dev *dev, struct mt76_queue *hwq)
481 {
482 	struct mt76_txq *mtxq, *mtxq_last;
483 	int len = 0;
484 
485 restart:
486 	mtxq_last = list_last_entry(&hwq->swq, struct mt76_txq, list);
487 	while (!list_empty(&hwq->swq)) {
488 		bool empty = false;
489 		int cur;
490 
491 		if (test_bit(MT76_OFFCHANNEL, &dev->state) ||
492 		    test_bit(MT76_RESET, &dev->state))
493 			return -EBUSY;
494 
495 		mtxq = list_first_entry(&hwq->swq, struct mt76_txq, list);
496 		if (mtxq->send_bar && mtxq->aggr) {
497 			struct ieee80211_txq *txq = mtxq_to_txq(mtxq);
498 			struct ieee80211_sta *sta = txq->sta;
499 			struct ieee80211_vif *vif = txq->vif;
500 			u16 agg_ssn = mtxq->agg_ssn;
501 			u8 tid = txq->tid;
502 
503 			mtxq->send_bar = false;
504 			spin_unlock_bh(&hwq->lock);
505 			ieee80211_send_bar(vif, sta->addr, tid, agg_ssn);
506 			spin_lock_bh(&hwq->lock);
507 			goto restart;
508 		}
509 
510 		list_del_init(&mtxq->list);
511 
512 		cur = mt76_txq_send_burst(dev, hwq, mtxq, &empty);
513 		if (!empty)
514 			list_add_tail(&mtxq->list, &hwq->swq);
515 
516 		if (cur < 0)
517 			return cur;
518 
519 		len += cur;
520 
521 		if (mtxq == mtxq_last)
522 			break;
523 	}
524 
525 	return len;
526 }
527 
528 void mt76_txq_schedule(struct mt76_dev *dev, struct mt76_queue *hwq)
529 {
530 	int len;
531 
532 	rcu_read_lock();
533 	do {
534 		if (hwq->swq_queued >= 4 || list_empty(&hwq->swq))
535 			break;
536 
537 		len = mt76_txq_schedule_list(dev, hwq);
538 	} while (len > 0);
539 	rcu_read_unlock();
540 }
541 EXPORT_SYMBOL_GPL(mt76_txq_schedule);
542 
543 void mt76_txq_schedule_all(struct mt76_dev *dev)
544 {
545 	int i;
546 
547 	for (i = 0; i <= MT_TXQ_BK; i++) {
548 		struct mt76_queue *q = &dev->q_tx[i];
549 
550 		spin_lock_bh(&q->lock);
551 		mt76_txq_schedule(dev, q);
552 		spin_unlock_bh(&q->lock);
553 	}
554 }
555 EXPORT_SYMBOL_GPL(mt76_txq_schedule_all);
556 
557 void mt76_stop_tx_queues(struct mt76_dev *dev, struct ieee80211_sta *sta,
558 			 bool send_bar)
559 {
560 	int i;
561 
562 	for (i = 0; i < ARRAY_SIZE(sta->txq); i++) {
563 		struct ieee80211_txq *txq = sta->txq[i];
564 		struct mt76_txq *mtxq;
565 
566 		if (!txq)
567 			continue;
568 
569 		mtxq = (struct mt76_txq *)txq->drv_priv;
570 
571 		spin_lock_bh(&mtxq->hwq->lock);
572 		mtxq->send_bar = mtxq->aggr && send_bar;
573 		if (!list_empty(&mtxq->list))
574 			list_del_init(&mtxq->list);
575 		spin_unlock_bh(&mtxq->hwq->lock);
576 	}
577 }
578 EXPORT_SYMBOL_GPL(mt76_stop_tx_queues);
579 
580 void mt76_wake_tx_queue(struct ieee80211_hw *hw, struct ieee80211_txq *txq)
581 {
582 	struct mt76_dev *dev = hw->priv;
583 	struct mt76_txq *mtxq = (struct mt76_txq *) txq->drv_priv;
584 	struct mt76_queue *hwq = mtxq->hwq;
585 
586 	if (!test_bit(MT76_STATE_RUNNING, &dev->state))
587 		return;
588 
589 	spin_lock_bh(&hwq->lock);
590 	if (list_empty(&mtxq->list))
591 		list_add_tail(&mtxq->list, &hwq->swq);
592 	mt76_txq_schedule(dev, hwq);
593 	spin_unlock_bh(&hwq->lock);
594 }
595 EXPORT_SYMBOL_GPL(mt76_wake_tx_queue);
596 
597 void mt76_txq_remove(struct mt76_dev *dev, struct ieee80211_txq *txq)
598 {
599 	struct mt76_txq *mtxq;
600 	struct mt76_queue *hwq;
601 	struct sk_buff *skb;
602 
603 	if (!txq)
604 		return;
605 
606 	mtxq = (struct mt76_txq *) txq->drv_priv;
607 	hwq = mtxq->hwq;
608 
609 	spin_lock_bh(&hwq->lock);
610 	if (!list_empty(&mtxq->list))
611 		list_del_init(&mtxq->list);
612 	spin_unlock_bh(&hwq->lock);
613 
614 	while ((skb = skb_dequeue(&mtxq->retry_q)) != NULL)
615 		ieee80211_free_txskb(dev->hw, skb);
616 }
617 EXPORT_SYMBOL_GPL(mt76_txq_remove);
618 
619 void mt76_txq_init(struct mt76_dev *dev, struct ieee80211_txq *txq)
620 {
621 	struct mt76_txq *mtxq = (struct mt76_txq *) txq->drv_priv;
622 
623 	INIT_LIST_HEAD(&mtxq->list);
624 	skb_queue_head_init(&mtxq->retry_q);
625 
626 	mtxq->hwq = &dev->q_tx[mt76_txq_get_qid(txq)];
627 }
628 EXPORT_SYMBOL_GPL(mt76_txq_init);
629 
630 u8 mt76_ac_to_hwq(u8 ac)
631 {
632 	static const u8 wmm_queue_map[] = {
633 		[IEEE80211_AC_BE] = 0,
634 		[IEEE80211_AC_BK] = 1,
635 		[IEEE80211_AC_VI] = 2,
636 		[IEEE80211_AC_VO] = 3,
637 	};
638 
639 	if (WARN_ON(ac >= IEEE80211_NUM_ACS))
640 		return 0;
641 
642 	return wmm_queue_map[ac];
643 }
644 EXPORT_SYMBOL_GPL(mt76_ac_to_hwq);
645