mt76: mt7921: enable rx hw de-amsdu

Enable hw rx-amsdu de-aggregation support available in 7921 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/mt7921/init.c

@@ -125,8 +125,8 @@ void mt7921_mac_init(struct mt7921_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);
 	mt76_clear(dev, MT_MDP_DCR0, MT_MDP_DCR0_RX_HDR_TRANS_EN);
 
 	for (i = 0; i < MT7921_WTBL_SIZE; i++)

drivers/net/wireless/mediatek/mt76/mt7921/mac.c

@@ -319,8 +319,9 @@ int mt7921_mac_fill_rx(struct mt7921_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;
 	u8 chfreq;
 
@@ -332,6 +333,9 @@ int mt7921_mac_fill_rx(struct mt7921_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;
+
 	chfreq = FIELD_GET(MT_RXD3_NORMAL_CH_FREQ, rxd3);
 	unicast = FIELD_GET(MT_RXD3_NORMAL_ADDR_TYPE, rxd3) == MT_RXD3_NORMAL_U2M;
 	idx = FIELD_GET(MT_RXD1_NORMAL_WLAN_IDX, rxd1);
@@ -540,6 +544,16 @@ int mt7921_mac_fill_rx(struct mt7921_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/mt7921/mac.h

@@ -88,6 +88,9 @@ 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)