mt76: mt7921: consider the invalid value for to_rssi

[ Upstream commit edb5aebc1c3db312e74e1dcf75b8626ee5300596 ]

It is possible the RCPI from the certain antenna is an invalid value,
especially packets are receiving while the system is frequently entering
deep sleep mode, so consider calculating RSSI with the reasonable upper
bound to avoid report the wrong value to the mac80211 layer.

Fixes: 163f4d22c118 ("mt76: mt7921: add MAC support")
Reviewed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
index ce4eae7f1e4485d2166019fccbffdb4aead5228b..39be2e39626981fb80837ba604f9a976e39f36b3 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
@@ -420,16 +420,19 @@ int mt7921_mac_fill_rx(struct mt7921_dev *dev, struct sk_buff *skb)
                status->chain_signal[1] = to_rssi(MT_PRXV_RCPI1, v1);
                status->chain_signal[2] = to_rssi(MT_PRXV_RCPI2, v1);
                status->chain_signal[3] = to_rssi(MT_PRXV_RCPI3, v1);
-               status->signal = status->chain_signal[0];
-
-               for (i = 1; i < hweight8(mphy->antenna_mask); i++) {
-                       if (!(status->chains & BIT(i)))
+               status->signal = -128;
+               for (i = 0; i < hweight8(mphy->antenna_mask); i++) {
+                       if (!(status->chains & BIT(i)) ||
+                           status->chain_signal[i] >= 0)
                                continue;
 
                        status->signal = max(status->signal,
                                             status->chain_signal[i]);
                }
 
+               if (status->signal == -128)
+                       status->flag |= RX_FLAG_NO_SIGNAL_VAL;
+
                stbc = FIELD_GET(MT_PRXV_STBC, v0);
                gi = FIELD_GET(MT_PRXV_SGI, v0);
                cck = false;