mt76: mt7915: enable hw rx-amsdu de-aggregation

Enable hw rx-amsdu de-aggregation support available in 7915 devices.
This is a preliminary patch to enable rx checksum offload
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mac80211.c

@@ -508,6 +508,39 @@ void mt76_free_device(struct mt76_dev *dev)
 }
 EXPORT_SYMBOL_GPL(mt76_free_device);
 
+static void mt76_rx_release_amsdu(struct mt76_phy *phy, enum mt76_rxq_id q)
+{
+	struct sk_buff *skb = phy->rx_amsdu[q].head;
+	struct mt76_dev *dev = phy->dev;
+
+	phy->rx_amsdu[q].head = NULL;
+	phy->rx_amsdu[q].tail = NULL;
+	__skb_queue_tail(&dev->rx_skb[q], skb);
+}
+
+static void mt76_rx_release_burst(struct mt76_phy *phy, enum mt76_rxq_id q,
+				  struct sk_buff *skb)
+{
+	struct mt76_rx_status *status = (struct mt76_rx_status *)skb->cb;
+
+	if (phy->rx_amsdu[q].head &&
+	    (!status->amsdu || status->first_amsdu ||
+	     status->seqno != phy->rx_amsdu[q].seqno))
+		mt76_rx_release_amsdu(phy, q);
+
+	if (!phy->rx_amsdu[q].head) {
+		phy->rx_amsdu[q].tail = &skb_shinfo(skb)->frag_list;
+		phy->rx_amsdu[q].seqno = status->seqno;
+		phy->rx_amsdu[q].head = skb;
+	} else {
+		*phy->rx_amsdu[q].tail = skb;
+		phy->rx_amsdu[q].tail = &skb->next;
+	}
+
+	if (!status->amsdu || status->last_amsdu)
+		mt76_rx_release_amsdu(phy, q);
+}
+
 void mt76_rx(struct mt76_dev *dev, enum mt76_rxq_id q, struct sk_buff *skb)
 {
 	struct mt76_rx_status *status = (struct mt76_rx_status *)skb->cb;
@@ -525,7 +558,8 @@ void mt76_rx(struct mt76_dev *dev, enum mt76_rxq_id q, struct sk_buff *skb)
 			phy->test.rx_stats.fcs_error[q]++;
 	}
 #endif
-	__skb_queue_tail(&dev->rx_skb[q], skb);
+
+	mt76_rx_release_burst(phy, q, skb);
 }
 EXPORT_SYMBOL_GPL(mt76_rx);
 
@@ -937,13 +971,26 @@ void mt76_rx_complete(struct mt76_dev *dev, struct sk_buff_head *frames,
 
 	spin_lock(&dev->rx_lock);
 	while ((skb = __skb_dequeue(frames)) != NULL) {
+		struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
+
 		if (mt76_check_ccmp_pn(skb)) {
 			dev_kfree_skb(skb);
 			continue;
 		}
 
+		skb_shinfo(skb)->frag_list = NULL;
 		mt76_rx_convert(dev, skb, &hw, &sta);
 		ieee80211_rx_list(hw, sta, skb, &list);
+
+		/* subsequent amsdu frames */
+		while (nskb) {
+			skb = nskb;
+			nskb = nskb->next;
+			skb->next = NULL;
+
+			mt76_rx_convert(dev, skb, &hw, &sta);
+			ieee80211_rx_list(hw, sta, skb, &list);
+		}
 	}
 	spin_unlock(&dev->rx_lock);
 

drivers/net/wireless/mediatek/mt76/mt76.h

@@ -507,6 +507,7 @@ struct mt76_rx_status {
 	u8 enc_flags;
 	u8 encoding:2, bw:3, he_ru:3;
 	u8 he_gi:2, he_dcm:1;
+	u8 amsdu:1, first_amsdu:1, last_amsdu:1;
 	u8 rate_idx;
 	u8 nss;
 	u8 band;
@@ -600,6 +601,12 @@ struct mt76_phy {
 
 	struct delayed_work mac_work;
 	u8 mac_work_count;
+
+	struct {
+		struct sk_buff *head;
+		struct sk_buff **tail;
+		u16 seqno;
+	} rx_amsdu[__MT_RXQ_MAX];
 };
 
 struct mt76_dev {

drivers/net/wireless/mediatek/mt76/mt7915/init.c

@@ -153,8 +153,8 @@ static void mt7915_mac_init(struct mt7915_dev *dev)
 	int i;
 
 	mt76_rmw_field(dev, MT_MDP_DCR1, MT_MDP_DCR1_MAX_RX_LEN, 1536);
-	/* disable hardware de-agg */
-	mt76_clear(dev, MT_MDP_DCR0, MT_MDP_DCR0_DAMSDU_EN);
+	/* enable hardware de-agg */
+	mt76_set(dev, MT_MDP_DCR0, MT_MDP_DCR0_DAMSDU_EN);
 
 	for (i = 0; i < MT7915_WTBL_SIZE; i++)
 		mt7915_mac_wtbl_update(dev, i,

drivers/net/wireless/mediatek/mt76/mt7915/mac.c

@@ -320,8 +320,9 @@ int mt7915_mac_fill_rx(struct mt7915_dev *dev, struct sk_buff *skb)
 	u32 rxd1 = le32_to_cpu(rxd[1]);
 	u32 rxd2 = le32_to_cpu(rxd[2]);
 	u32 rxd3 = le32_to_cpu(rxd[3]);
+	u32 rxd4 = le32_to_cpu(rxd[4]);
 	bool unicast, insert_ccmp_hdr = false;
-	u8 remove_pad;
+	u8 remove_pad, amsdu_info;
 	int i, idx;
 
 	memset(status, 0, sizeof(*status));
@@ -338,6 +339,9 @@ int mt7915_mac_fill_rx(struct mt7915_dev *dev, struct sk_buff *skb)
 	if (!test_bit(MT76_STATE_RUNNING, &mphy->state))
 		return -EINVAL;
 
+	if (rxd2 & MT_RXD2_NORMAL_AMSDU_ERR)
+		return -EINVAL;
+
 	unicast = FIELD_GET(MT_RXD3_NORMAL_ADDR_TYPE, rxd3) == MT_RXD3_NORMAL_U2M;
 	idx = FIELD_GET(MT_RXD1_NORMAL_WLAN_IDX, rxd1);
 	status->wcid = mt7915_rx_get_wcid(dev, idx, unicast);
@@ -541,6 +545,16 @@ int mt7915_mac_fill_rx(struct mt7915_dev *dev, struct sk_buff *skb)
 
 	skb_pull(skb, (u8 *)rxd - skb->data + 2 * remove_pad);
 
+	amsdu_info = FIELD_GET(MT_RXD4_NORMAL_PAYLOAD_FORMAT, rxd4);
+	status->amsdu = !!amsdu_info;
+	if (status->amsdu) {
+		status->first_amsdu = amsdu_info == MT_RXD4_FIRST_AMSDU_FRAME;
+		status->last_amsdu = amsdu_info == MT_RXD4_LAST_AMSDU_FRAME;
+		memmove(skb->data + 2, skb->data,
+			ieee80211_get_hdrlen_from_skb(skb));
+		skb_pull(skb, 2);
+	}
+
 	if (insert_ccmp_hdr) {
 		u8 key_id = FIELD_GET(MT_RXD1_NORMAL_KEY_ID, rxd1);
 

drivers/net/wireless/mediatek/mt76/mt7915/mac.h

@@ -86,6 +86,10 @@ enum rx_pkt_type {
 
 /* RXD DW4 */
 #define MT_RXD4_NORMAL_PAYLOAD_FORMAT	GENMASK(1, 0)
+#define MT_RXD4_FIRST_AMSDU_FRAME	GENMASK(1, 0)
+#define MT_RXD4_MID_AMSDU_FRAME		BIT(1)
+#define MT_RXD4_LAST_AMSDU_FRAME	BIT(0)
+
 #define MT_RXD4_NORMAL_PATTERN_DROP	BIT(9)
 #define MT_RXD4_NORMAL_CLS		BIT(10)
 #define MT_RXD4_NORMAL_OFLD		GENMASK(12, 11)