mt76: mt7921: reduce the data latency during hw scan

Reduce the data latency during hw_scan by the split scan which would switch
back to operational channel right after scanning each channel done.
Suggested-by: Asda Wen <Asda.Wen@mediatek.com>
Suggested-by: Soul Huang <Soul.Huang@mediatek.com>
Co-developed-by: YN Chen <YN.Chen@mediatek.com>
Signed-off-by: YN Chen <YN.Chen@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c

@@ -1395,11 +1395,14 @@ int mt76_connac_mcu_hw_scan(struct mt76_phy *phy, struct ieee80211_vif *vif,
 		req->ies_len = cpu_to_le16(sreq->ie_len);
 	}
 
+	if (is_mt7921(phy->dev))
+		req->scan_func |= SCAN_FUNC_SPLIT_SCAN;
+
 	memcpy(req->bssid, sreq->bssid, ETH_ALEN);
 	if (sreq->flags & NL80211_SCAN_FLAG_RANDOM_ADDR) {
 		get_random_mask_addr(req->random_mac, sreq->mac_addr,
 				     sreq->mac_addr_mask);
-		req->scan_func = 1;
+		req->scan_func |= SCAN_FUNC_RANDOM_MAC;
 	}
 
 	err = mt76_mcu_skb_send_msg(mdev, skb, MCU_CMD_START_HW_SCAN, false);

drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.h

@@ -362,6 +362,9 @@ enum {
 #define NETWORK_IBSS			BIT(18)
 #define NETWORK_WDS			BIT(21)
 
+#define SCAN_FUNC_RANDOM_MAC		BIT(0)
+#define SCAN_FUNC_SPLIT_SCAN		BIT(5)
+
 #define CONNECTION_INFRA_STA		(STA_TYPE_STA | NETWORK_INFRA)
 #define CONNECTION_INFRA_AP		(STA_TYPE_AP | NETWORK_INFRA)
 #define CONNECTION_P2P_GC		(STA_TYPE_STA | NETWORK_P2P)