mac80211: HE: set RX NSS

In case of HE, the RX NSS is taken from the HE capabilities.
If the supported NSS capabilities that are reported by AP for
HE mode in the HE Capabilities element are different from the NSS
capabilities that are reported by AP for the VHT mode in the VHT
Capabilities element, use the lowest supported NSS to not get all
the values confused.
Signed-off-by: NTova Mussai <tova.mussai@intel.com>
Signed-off-by: NLuca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/20200131111300.891737-9-luca@coelho.fiSigned-off-by: NJohannes Berg <johannes.berg@intel.com>

net/mac80211/vht.c

@@ -481,12 +481,40 @@ enum ieee80211_sta_rx_bandwidth ieee80211_sta_cur_vht_bw(struct sta_info *sta)
 
 void ieee80211_sta_set_rx_nss(struct sta_info *sta)
 {
-	u8 ht_rx_nss = 0, vht_rx_nss = 0;
+	u8 ht_rx_nss = 0, vht_rx_nss = 0, he_rx_nss = 0, rx_nss;
 
 	/* if we received a notification already don't overwrite it */
 	if (sta->sta.rx_nss)
 		return;
 
+	if (sta->sta.he_cap.has_he) {
+		int i;
+		u8 rx_mcs_80 = 0, rx_mcs_160 = 0;
+		const struct ieee80211_sta_he_cap *he_cap = &sta->sta.he_cap;
+		u16 mcs_160_map =
+			le16_to_cpu(he_cap->he_mcs_nss_supp.rx_mcs_160);
+		u16 mcs_80_map = le16_to_cpu(he_cap->he_mcs_nss_supp.rx_mcs_80);
+
+		for (i = 7; i >= 0; i--) {
+			u8 mcs_160 = (mcs_160_map >> (2 * i)) & 3;
+
+			if (mcs_160 != IEEE80211_VHT_MCS_NOT_SUPPORTED) {
+				rx_mcs_160 = i + 1;
+				break;
+			}
+		}
+		for (i = 7; i >= 0; i--) {
+			u8 mcs_80 = (mcs_80_map >> (2 * i)) & 3;
+
+			if (mcs_80 != IEEE80211_VHT_MCS_NOT_SUPPORTED) {
+				rx_mcs_80 = i + 1;
+				break;
+			}
+		}
+
+		he_rx_nss = min(rx_mcs_80, rx_mcs_160);
+	}
+
 	if (sta->sta.ht_cap.ht_supported) {
 		if (sta->sta.ht_cap.mcs.rx_mask[0])
 			ht_rx_nss++;
@@ -516,8 +544,9 @@ void ieee80211_sta_set_rx_nss(struct sta_info *sta)
 		/* FIXME: consider rx_highest? */
 	}
 
-	ht_rx_nss = max(ht_rx_nss, vht_rx_nss);
-	sta->sta.rx_nss = max_t(u8, 1, ht_rx_nss);
+	rx_nss = max(vht_rx_nss, ht_rx_nss);
+	rx_nss = max(he_rx_nss, rx_nss);
+	sta->sta.rx_nss = max_t(u8, 1, rx_nss);
 }
 
 u32 __ieee80211_vht_handle_opmode(struct ieee80211_sub_if_data *sdata,