mt76: mt7915: fix rxrate reporting

Avoid directly updating sinfo->rxrate from firmware since rate_info might
be overwritten by wrong results even mt7915_mcu_get_rx_rate() fails check.

Add more error handlings accordingly.

Fixes: 11553d88 ("mt76: mt7915: query station rx rate from firmware")
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

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

@@ -839,9 +839,12 @@ static void mt7915_sta_statistics(struct ieee80211_hw *hw,
 	struct mt7915_phy *phy = mt7915_hw_phy(hw);
 	struct mt7915_sta *msta = (struct mt7915_sta *)sta->drv_priv;
 	struct mt7915_sta_stats *stats = &msta->stats;
+	struct rate_info rxrate = {};
 
-	if (mt7915_mcu_get_rx_rate(phy, vif, sta, &sinfo->rxrate) == 0)
+	if (!mt7915_mcu_get_rx_rate(phy, vif, sta, &rxrate)) {
+		sinfo->rxrate = rxrate;
 		sinfo->filled |= BIT_ULL(NL80211_STA_INFO_RX_BITRATE);
+	}
 
 	if (!stats->tx_rate.legacy && !stats->tx_rate.flags)
 		return;

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

@@ -3552,9 +3552,8 @@ int mt7915_mcu_get_rx_rate(struct mt7915_phy *phy, struct ieee80211_vif *vif,
 	struct ieee80211_supported_band *sband;
 	struct mt7915_mcu_phy_rx_info *res;
 	struct sk_buff *skb;
-	u16 flags = 0;
 	int ret;
-	int i;
+	bool cck = false;
 
 	ret = mt76_mcu_send_and_get_msg(&dev->mt76, MCU_EXT_CMD(PHY_STAT_INFO),
 					&req, sizeof(req), true, &skb);
@@ -3568,48 +3567,53 @@ int mt7915_mcu_get_rx_rate(struct mt7915_phy *phy, struct ieee80211_vif *vif,
 
 	switch (res->mode) {
 	case MT_PHY_TYPE_CCK:
+		cck = true;
+		fallthrough;
 	case MT_PHY_TYPE_OFDM:
 		if (mphy->chandef.chan->band == NL80211_BAND_5GHZ)
 			sband = &mphy->sband_5g.sband;
 		else
 			sband = &mphy->sband_2g.sband;
 
-		for (i = 0; i < sband->n_bitrates; i++) {
-			if (rate->mcs != (sband->bitrates[i].hw_value & 0xf))
-				continue;
-
-			rate->legacy = sband->bitrates[i].bitrate;
-			break;
-		}
+		rate->mcs = mt76_get_rate(&dev->mt76, sband, rate->mcs, cck);
+		rate->legacy = sband->bitrates[rate->mcs].bitrate;
 		break;
 	case MT_PHY_TYPE_HT:
 	case MT_PHY_TYPE_HT_GF:
-		if (rate->mcs > 31)
-			return -EINVAL;
-
-		flags |= RATE_INFO_FLAGS_MCS;
+		if (rate->mcs > 31) {
+			ret = -EINVAL;
+			goto out;
+		}
 
+		rate->flags = RATE_INFO_FLAGS_MCS;
 		if (res->gi)
-			flags |= RATE_INFO_FLAGS_SHORT_GI;
+			rate->flags |= RATE_INFO_FLAGS_SHORT_GI;
 		break;
 	case MT_PHY_TYPE_VHT:
-		flags |= RATE_INFO_FLAGS_VHT_MCS;
+		if (rate->mcs > 9) {
+			ret = -EINVAL;
+			goto out;
+		}
 
+		rate->flags = RATE_INFO_FLAGS_VHT_MCS;
 		if (res->gi)
-			flags |= RATE_INFO_FLAGS_SHORT_GI;
+			rate->flags |= RATE_INFO_FLAGS_SHORT_GI;
 		break;
 	case MT_PHY_TYPE_HE_SU:
 	case MT_PHY_TYPE_HE_EXT_SU:
 	case MT_PHY_TYPE_HE_TB:
 	case MT_PHY_TYPE_HE_MU:
+		if (res->gi > NL80211_RATE_INFO_HE_GI_3_2 || rate->mcs > 11) {
+			ret = -EINVAL;
+			goto out;
+		}
 		rate->he_gi = res->gi;
-
-		flags |= RATE_INFO_FLAGS_HE_MCS;
+		rate->flags = RATE_INFO_FLAGS_HE_MCS;
 		break;
 	default:
-		break;
+		ret = -EINVAL;
+		goto out;
 	}
-	rate->flags = flags;
 
 	switch (res->bw) {
 	case IEEE80211_STA_RX_BW_160:
@@ -3626,7 +3630,8 @@ int mt7915_mcu_get_rx_rate(struct mt7915_phy *phy, struct ieee80211_vif *vif,
 		break;
 	}
 
+out:
 	dev_kfree_skb(skb);
 
-	return 0;
+	return ret;
 }