mt76: mt7915: fix phy cap in mt7915_set_stream_he_txbf_caps()

This patch fixes performance issue of beamforming tx on
bandwidth 160MHz.

Fixes: 99ad32a4 ("mt76: mt7915: add support for MT7986")
Signed-off-by: NPeter Chiu <chui-hao.chiu@mediatek.com>
Signed-off-by: NShayne Chen <shayne.chen@mediatek.com>
Signed-off-by: NFelix Fietkau <nbd@nbd.name>

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

@@ -726,11 +726,18 @@ void mt7915_set_stream_vht_txbf_caps(struct mt7915_phy *phy)
 }
 
 static void
-mt7915_set_stream_he_txbf_caps(struct ieee80211_sta_he_cap *he_cap,
+mt7915_set_stream_he_txbf_caps(struct mt7915_dev *dev,
+			       struct ieee80211_sta_he_cap *he_cap,
 			       int vif, int nss)
 {
 	struct ieee80211_he_cap_elem *elem = &he_cap->he_cap_elem;
-	u8 c;
+	u8 c, nss_160;
+
+	/* Can do 1/2 of NSS streams in 160Mhz mode for mt7915 */
+	if (is_mt7915(&dev->mt76) && !dev->dbdc_support)
+		nss_160 = nss / 2;
+	else
+		nss_160 = nss;
 
 #ifdef CONFIG_MAC80211_MESH
 	if (vif == NL80211_IFTYPE_MESH_POINT)
@@ -784,13 +791,21 @@ mt7915_set_stream_he_txbf_caps(struct ieee80211_sta_he_cap *he_cap,
 	/* num_snd_dim
 	 * for mt7915, max supported nss is 2 for bw > 80MHz
 	 */
-	c = (nss - 1) |
-	    IEEE80211_HE_PHY_CAP5_BEAMFORMEE_NUM_SND_DIM_ABOVE_80MHZ_2;
+	c = FIELD_PREP(IEEE80211_HE_PHY_CAP5_BEAMFORMEE_NUM_SND_DIM_UNDER_80MHZ_MASK,
+		       nss - 1) |
+	    FIELD_PREP(IEEE80211_HE_PHY_CAP5_BEAMFORMEE_NUM_SND_DIM_ABOVE_80MHZ_MASK,
+		       nss_160 - 1);
 	elem->phy_cap_info[5] |= c;
 
 	c = IEEE80211_HE_PHY_CAP6_TRIG_SU_BEAMFORMING_FB |
 	    IEEE80211_HE_PHY_CAP6_TRIG_MU_BEAMFORMING_PARTIAL_BW_FB;
 	elem->phy_cap_info[6] |= c;
+
+	if (!is_mt7915(&dev->mt76)) {
+		c = IEEE80211_HE_PHY_CAP7_STBC_TX_ABOVE_80MHZ |
+		    IEEE80211_HE_PHY_CAP7_STBC_RX_ABOVE_80MHZ;
+		elem->phy_cap_info[7] |= c;
+	}
 }
 
 static void
@@ -952,7 +967,7 @@ mt7915_init_he_caps(struct mt7915_phy *phy, enum nl80211_band band,
 		he_mcs->rx_mcs_80p80 = cpu_to_le16(mcs_map_160);
 		he_mcs->tx_mcs_80p80 = cpu_to_le16(mcs_map_160);
 
-		mt7915_set_stream_he_txbf_caps(he_cap, i, nss);
+		mt7915_set_stream_he_txbf_caps(dev, he_cap, i, nss);
 
 		memset(he_cap->ppe_thres, 0, sizeof(he_cap->ppe_thres));
 		if (he_cap_elem->phy_cap_info[6] &