brcmfmac: add fallback for devices that do not report per-chain values

BugLink: https://bugs.launchpad.net/bugs/1878232

commit 94abd778 upstream.

If brcmf_cfg80211_get_station fails to determine the RSSI from the
per-chain values get the value individually as a fallback.

Fixes: 1f0dc59a ("brcmfmac: rework .get_station() callback")
Signed-off-by: Jaap Jan Meijer <jjmeijer88@gmail.com>
Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/net/wireless/brcm80211/brcmfmac/cfg80211.c

@@ -2419,12 +2419,14 @@ brcmf_cfg80211_get_station(struct wiphy *wiphy, struct net_device *ndev,
 			   const u8 *mac, struct station_info *sinfo)
 {
 	struct brcmf_if *ifp = netdev_priv(ndev);
+	struct brcmf_scb_val_le scb_val;
 	s32 err = 0;
 	struct brcmf_sta_info_le sta_info_le;
 	u32 sta_flags;
 	u32 is_tdls_peer;
 	s32 total_rssi;
 	s32 count_rssi;
+	int rssi;
 	u32 i;
 
 	brcmf_dbg(TRACE, "Enter, MAC %pM\n", mac);
@@ -2505,6 +2507,20 @@ brcmf_cfg80211_get_station(struct wiphy *wiphy, struct net_device *ndev,
 			sinfo->filled |= BIT(NL80211_STA_INFO_SIGNAL);
 			total_rssi /= count_rssi;
 			sinfo->signal = total_rssi;
+		} else if (test_bit(BRCMF_VIF_STATUS_CONNECTED,
+			&ifp->vif->sme_state)) {
+			memset(&scb_val, 0, sizeof(scb_val));
+			err = brcmf_fil_cmd_data_get(ifp, BRCMF_C_GET_RSSI,
+						     &scb_val, sizeof(scb_val));
+			if (err) {
+				brcmf_err("Could not get rssi (%d)\n", err);
+				goto done;
+			} else {
+				rssi = le32_to_cpu(scb_val.val);
+				sinfo->filled |= BIT(NL80211_STA_INFO_SIGNAL);
+				sinfo->signal = rssi;
+				brcmf_dbg(CONN, "RSSI %d dBm\n", rssi);
+			}
 		}
 	}
 done: