tx.c

/*
 * Copyright (C) 2016 Felix Fietkau <nbd@nbd.name>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "mt76.h"

static struct mt76_txwi_cache *
mt76_alloc_txwi(struct mt76_dev *dev)
{
	struct mt76_txwi_cache *t;
	dma_addr_t addr;
	int size;

	size = (sizeof(*t) + L1_CACHE_BYTES - 1) & ~(L1_CACHE_BYTES - 1);
	t = devm_kzalloc(dev->dev, size, GFP_ATOMIC);
	if (!t)
		return NULL;

	addr = dma_map_single(dev->dev, &t->txwi, sizeof(t->txwi),
			      DMA_TO_DEVICE);
	t->dma_addr = addr;

	return t;
}

static struct mt76_txwi_cache *
__mt76_get_txwi(struct mt76_dev *dev)
{
	struct mt76_txwi_cache *t = NULL;

	spin_lock_bh(&dev->lock);
	if (!list_empty(&dev->txwi_cache)) {
		t = list_first_entry(&dev->txwi_cache, struct mt76_txwi_cache,
				     list);
		list_del(&t->list);
	}
	spin_unlock_bh(&dev->lock);

	return t;
}

struct mt76_txwi_cache *
mt76_get_txwi(struct mt76_dev *dev)
{
	struct mt76_txwi_cache *t = __mt76_get_txwi(dev);

	if (t)
		return t;

	return mt76_alloc_txwi(dev);
}

void
mt76_put_txwi(struct mt76_dev *dev, struct mt76_txwi_cache *t)
{
	if (!t)
		return;

	spin_lock_bh(&dev->lock);
	list_add(&t->list, &dev->txwi_cache);
	spin_unlock_bh(&dev->lock);
}

void mt76_tx_free(struct mt76_dev *dev)
{
	struct mt76_txwi_cache *t;

	while ((t = __mt76_get_txwi(dev)) != NULL)
		dma_unmap_single(dev->dev, t->dma_addr, sizeof(t->txwi),
				 DMA_TO_DEVICE);
}

static int
mt76_txq_get_qid(struct ieee80211_txq *txq)
{
	if (!txq->sta)
		return MT_TXQ_BE;

	return txq->ac;
}

static void
mt76_check_agg_ssn(struct mt76_txq *mtxq, struct sk_buff *skb)
{
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;

	if (!ieee80211_is_data_qos(hdr->frame_control) ||
	    !ieee80211_is_data_present(hdr->frame_control))
		return;

	mtxq->agg_ssn = le16_to_cpu(hdr->seq_ctrl) + 0x10;
}

void
mt76_tx(struct mt76_dev *dev, struct ieee80211_sta *sta,
	struct mt76_wcid *wcid, struct sk_buff *skb)
{
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
	struct mt76_queue *q;
	int qid = skb_get_queue_mapping(skb);

	if (WARN_ON(qid >= MT_TXQ_PSD)) {
		qid = MT_TXQ_BE;
		skb_set_queue_mapping(skb, qid);
	}

	if (!wcid->tx_rate_set)
		ieee80211_get_tx_rates(info->control.vif, sta, skb,
				       info->control.rates, 1);

	if (sta && ieee80211_is_data_qos(hdr->frame_control)) {
		struct ieee80211_txq *txq;
		struct mt76_txq *mtxq;
		u8 tid;

		tid = skb->priority & IEEE80211_QOS_CTL_TID_MASK;
		txq = sta->txq[tid];
		mtxq = (struct mt76_txq *) txq->drv_priv;

		if (mtxq->aggr)
			mt76_check_agg_ssn(mtxq, skb);
	}

	q = &dev->q_tx[qid];

	spin_lock_bh(&q->lock);
	dev->queue_ops->tx_queue_skb(dev, q, skb, wcid, sta);
	dev->queue_ops->kick(dev, q);

	if (q->queued > q->ndesc - 8)
		ieee80211_stop_queue(dev->hw, skb_get_queue_mapping(skb));
	spin_unlock_bh(&q->lock);
}
EXPORT_SYMBOL_GPL(mt76_tx);

static struct sk_buff *
mt76_txq_dequeue(struct mt76_dev *dev, struct mt76_txq *mtxq, bool ps)
{
	struct ieee80211_txq *txq = mtxq_to_txq(mtxq);
	struct sk_buff *skb;

	skb = skb_dequeue(&mtxq->retry_q);
	if (skb) {
		u8 tid = skb->priority & IEEE80211_QOS_CTL_TID_MASK;

		if (ps && skb_queue_empty(&mtxq->retry_q))
			ieee80211_sta_set_buffered(txq->sta, tid, false);

		return skb;
	}

	skb = ieee80211_tx_dequeue(dev->hw, txq);
	if (!skb)
		return NULL;

	return skb;
}

static void
mt76_queue_ps_skb(struct mt76_dev *dev, struct ieee80211_sta *sta,
		  struct sk_buff *skb, bool last)
{
	struct mt76_wcid *wcid = (struct mt76_wcid *) sta->drv_priv;
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
	struct mt76_queue *hwq = &dev->q_tx[MT_TXQ_PSD];

	info->control.flags |= IEEE80211_TX_CTRL_PS_RESPONSE;
	if (last)
		info->flags |= IEEE80211_TX_STATUS_EOSP;

	mt76_skb_set_moredata(skb, !last);
	dev->queue_ops->tx_queue_skb(dev, hwq, skb, wcid, sta);
}

void
mt76_release_buffered_frames(struct ieee80211_hw *hw, struct ieee80211_sta *sta,
			     u16 tids, int nframes,
			     enum ieee80211_frame_release_type reason,
			     bool more_data)
{
	struct mt76_dev *dev = hw->priv;
	struct sk_buff *last_skb = NULL;
	struct mt76_queue *hwq = &dev->q_tx[MT_TXQ_PSD];
	int i;

	spin_lock_bh(&hwq->lock);
	for (i = 0; tids && nframes; i++, tids >>= 1) {
		struct ieee80211_txq *txq = sta->txq[i];
		struct mt76_txq *mtxq = (struct mt76_txq *) txq->drv_priv;
		struct sk_buff *skb;

		if (!(tids & 1))
			continue;

		do {
			skb = mt76_txq_dequeue(dev, mtxq, true);
			if (!skb)
				break;

			if (mtxq->aggr)
				mt76_check_agg_ssn(mtxq, skb);

			nframes--;
			if (last_skb)
				mt76_queue_ps_skb(dev, sta, last_skb, false);

			last_skb = skb;
		} while (nframes);
	}

	if (last_skb) {
		mt76_queue_ps_skb(dev, sta, last_skb, true);
		dev->queue_ops->kick(dev, hwq);
	}
	spin_unlock_bh(&hwq->lock);
}
EXPORT_SYMBOL_GPL(mt76_release_buffered_frames);

static int
mt76_txq_send_burst(struct mt76_dev *dev, struct mt76_queue *hwq,
		    struct mt76_txq *mtxq, bool *empty)
{
	struct ieee80211_txq *txq = mtxq_to_txq(mtxq);
	struct ieee80211_tx_info *info;
	struct mt76_wcid *wcid = mtxq->wcid;
	struct sk_buff *skb;
	int n_frames = 1, limit;
	struct ieee80211_tx_rate tx_rate;
	bool ampdu;
	bool probe;
	int idx;

	skb = mt76_txq_dequeue(dev, mtxq, false);
	if (!skb) {
		*empty = true;
		return 0;
	}

	info = IEEE80211_SKB_CB(skb);
	if (!wcid->tx_rate_set)
		ieee80211_get_tx_rates(txq->vif, txq->sta, skb,
				       info->control.rates, 1);
	tx_rate = info->control.rates[0];

	probe = (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE);
	ampdu = IEEE80211_SKB_CB(skb)->flags & IEEE80211_TX_CTL_AMPDU;
	limit = ampdu ? 16 : 3;

	if (ampdu)
		mt76_check_agg_ssn(mtxq, skb);

	idx = dev->queue_ops->tx_queue_skb(dev, hwq, skb, wcid, txq->sta);

	if (idx < 0)
		return idx;

	do {
		bool cur_ampdu;

		if (probe)
			break;

		if (test_bit(MT76_OFFCHANNEL, &dev->state) ||
		    test_bit(MT76_RESET, &dev->state))
			return -EBUSY;

		skb = mt76_txq_dequeue(dev, mtxq, false);
		if (!skb) {
			*empty = true;
			break;
		}

		info = IEEE80211_SKB_CB(skb);
		cur_ampdu = info->flags & IEEE80211_TX_CTL_AMPDU;

		if (ampdu != cur_ampdu ||
		    (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)) {
			skb_queue_tail(&mtxq->retry_q, skb);
			break;
		}

		info->control.rates[0] = tx_rate;

		if (cur_ampdu)
			mt76_check_agg_ssn(mtxq, skb);

		idx = dev->queue_ops->tx_queue_skb(dev, hwq, skb, wcid,
						   txq->sta);
		if (idx < 0)
			return idx;

		n_frames++;
	} while (n_frames < limit);

	if (!probe) {
		hwq->swq_queued++;
		hwq->entry[idx].schedule = true;
	}

	dev->queue_ops->kick(dev, hwq);

	return n_frames;
}

static int
mt76_txq_schedule_list(struct mt76_dev *dev, struct mt76_queue *hwq)
{
	struct mt76_txq *mtxq, *mtxq_last;
	int len = 0;

restart:
	mtxq_last = list_last_entry(&hwq->swq, struct mt76_txq, list);
	while (!list_empty(&hwq->swq)) {
		bool empty = false;
		int cur;

		if (test_bit(MT76_OFFCHANNEL, &dev->state) ||
		    test_bit(MT76_RESET, &dev->state))
			return -EBUSY;

		mtxq = list_first_entry(&hwq->swq, struct mt76_txq, list);
		if (mtxq->send_bar && mtxq->aggr) {
			struct ieee80211_txq *txq = mtxq_to_txq(mtxq);
			struct ieee80211_sta *sta = txq->sta;
			struct ieee80211_vif *vif = txq->vif;
			u16 agg_ssn = mtxq->agg_ssn;
			u8 tid = txq->tid;

			mtxq->send_bar = false;
			spin_unlock_bh(&hwq->lock);
			ieee80211_send_bar(vif, sta->addr, tid, agg_ssn);
			spin_lock_bh(&hwq->lock);
			goto restart;
		}

		list_del_init(&mtxq->list);

		cur = mt76_txq_send_burst(dev, hwq, mtxq, &empty);
		if (!empty)
			list_add_tail(&mtxq->list, &hwq->swq);

		if (cur < 0)
			return cur;

		len += cur;

		if (mtxq == mtxq_last)
			break;
	}

	return len;
}

void mt76_txq_schedule(struct mt76_dev *dev, struct mt76_queue *hwq)
{
	int len;

	rcu_read_lock();
	do {
		if (hwq->swq_queued >= 4 || list_empty(&hwq->swq))
			break;

		len = mt76_txq_schedule_list(dev, hwq);
	} while (len > 0);
	rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(mt76_txq_schedule);

void mt76_txq_schedule_all(struct mt76_dev *dev)
{
	int i;

	for (i = 0; i <= MT_TXQ_BK; i++) {
		struct mt76_queue *q = &dev->q_tx[i];

		spin_lock_bh(&q->lock);
		mt76_txq_schedule(dev, q);
		spin_unlock_bh(&q->lock);
	}
}
EXPORT_SYMBOL_GPL(mt76_txq_schedule_all);

void mt76_stop_tx_queues(struct mt76_dev *dev, struct ieee80211_sta *sta,
			 bool send_bar)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(sta->txq); i++) {
		struct ieee80211_txq *txq = sta->txq[i];
		struct mt76_txq *mtxq = (struct mt76_txq *) txq->drv_priv;

		spin_lock_bh(&mtxq->hwq->lock);
		mtxq->send_bar = mtxq->aggr && send_bar;
		if (!list_empty(&mtxq->list))
			list_del_init(&mtxq->list);
		spin_unlock_bh(&mtxq->hwq->lock);
	}
}
EXPORT_SYMBOL_GPL(mt76_stop_tx_queues);

void mt76_wake_tx_queue(struct ieee80211_hw *hw, struct ieee80211_txq *txq)
{
	struct mt76_dev *dev = hw->priv;
	struct mt76_txq *mtxq = (struct mt76_txq *) txq->drv_priv;
	struct mt76_queue *hwq = mtxq->hwq;

	spin_lock_bh(&hwq->lock);
	if (list_empty(&mtxq->list))
		list_add_tail(&mtxq->list, &hwq->swq);
	mt76_txq_schedule(dev, hwq);
	spin_unlock_bh(&hwq->lock);
}
EXPORT_SYMBOL_GPL(mt76_wake_tx_queue);

void mt76_txq_remove(struct mt76_dev *dev, struct ieee80211_txq *txq)
{
	struct mt76_txq *mtxq;
	struct mt76_queue *hwq;
	struct sk_buff *skb;

	if (!txq)
		return;

	mtxq = (struct mt76_txq *) txq->drv_priv;
	hwq = mtxq->hwq;

	spin_lock_bh(&hwq->lock);
	if (!list_empty(&mtxq->list))
		list_del(&mtxq->list);
	spin_unlock_bh(&hwq->lock);

	while ((skb = skb_dequeue(&mtxq->retry_q)) != NULL)
		ieee80211_free_txskb(dev->hw, skb);
}
EXPORT_SYMBOL_GPL(mt76_txq_remove);

void mt76_txq_init(struct mt76_dev *dev, struct ieee80211_txq *txq)
{
	struct mt76_txq *mtxq = (struct mt76_txq *) txq->drv_priv;

	INIT_LIST_HEAD(&mtxq->list);
	skb_queue_head_init(&mtxq->retry_q);

	mtxq->hwq = &dev->q_tx[mt76_txq_get_qid(txq)];
}
EXPORT_SYMBOL_GPL(mt76_txq_init);

u8 mt76_ac_to_hwq(u8 ac)
{
	static const u8 wmm_queue_map[] = {
		[IEEE80211_AC_BE] = 0,
		[IEEE80211_AC_BK] = 1,
		[IEEE80211_AC_VI] = 2,
		[IEEE80211_AC_VO] = 3,
	};

	if (WARN_ON(ac >= IEEE80211_NUM_ACS))
		return 0;

	return wmm_queue_map[ac];
}
EXPORT_SYMBOL_GPL(mt76_ac_to_hwq);