wifi: mt76: mt7996: add support for variants with auxiliary RX path

Add support to correctly configure the rx chainmask of variants that
have additional auxiliary RX path. e.g., 4T5R.
The auxiliary RX path is transparent to driver, but driver needs to
correctly configure it in the set channel fw command.
Co-developed-by: StanleyYP Wang <StanleyYP.Wang@mediatek.com>
Signed-off-by: StanleyYP Wang <StanleyYP.Wang@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7996/eeprom.c

@@ -148,36 +148,49 @@ static int mt7996_eeprom_parse_band_config(struct mt7996_phy *phy)
 
 int mt7996_eeprom_parse_hw_cap(struct mt7996_dev *dev, struct mt7996_phy *phy)
 {
-	u8 path, nss, band_idx = phy->mt76->band_idx;
+	u8 path, rx_path, nss, band_idx = phy->mt76->band_idx;
 	u8 *eeprom = dev->mt76.eeprom.data;
 	struct mt76_phy *mphy = phy->mt76;
+	int max_path = 5, max_nss = 4;
 	int ret;
 
 	switch (band_idx) {
 	case MT_BAND1:
 		path = FIELD_GET(MT_EE_WIFI_CONF2_TX_PATH_BAND1,
 				 eeprom[MT_EE_WIFI_CONF + 2]);
+		rx_path = FIELD_GET(MT_EE_WIFI_CONF3_RX_PATH_BAND1,
+				    eeprom[MT_EE_WIFI_CONF + 3]);
 		nss = FIELD_GET(MT_EE_WIFI_CONF5_STREAM_NUM_BAND1,
 				eeprom[MT_EE_WIFI_CONF + 5]);
 		break;
 	case MT_BAND2:
 		path = FIELD_GET(MT_EE_WIFI_CONF2_TX_PATH_BAND2,
 				 eeprom[MT_EE_WIFI_CONF + 2]);
+		rx_path = FIELD_GET(MT_EE_WIFI_CONF4_RX_PATH_BAND2,
+				    eeprom[MT_EE_WIFI_CONF + 4]);
 		nss = FIELD_GET(MT_EE_WIFI_CONF5_STREAM_NUM_BAND2,
 				eeprom[MT_EE_WIFI_CONF + 5]);
 		break;
 	default:
 		path = FIELD_GET(MT_EE_WIFI_CONF1_TX_PATH_BAND0,
 				 eeprom[MT_EE_WIFI_CONF + 1]);
+		rx_path = FIELD_GET(MT_EE_WIFI_CONF3_RX_PATH_BAND0,
+				    eeprom[MT_EE_WIFI_CONF + 3]);
 		nss = FIELD_GET(MT_EE_WIFI_CONF4_STREAM_NUM_BAND0,
 				eeprom[MT_EE_WIFI_CONF + 4]);
 		break;
 	}
 
-	if (!path || path > 4)
-		path = 4;
+	if (!path || path > max_path)
+		path = max_path;
 
-	nss = min_t(u8, min_t(u8, 4, nss), path);
+	if (!nss || nss > max_nss)
+		nss = max_nss;
+
+	nss = min_t(u8, nss, path);
+
+	if (path != rx_path)
+		phy->has_aux_rx = true;
 
 	mphy->antenna_mask = BIT(nss) - 1;
 	mphy->chainmask = (BIT(path) - 1) << dev->chainshift[band_idx];

drivers/net/wireless/mediatek/mt76/mt7996/eeprom.h

@@ -33,6 +33,9 @@ enum mt7996_eeprom_field {
 #define MT_EE_WIFI_CONF1_TX_PATH_BAND0		GENMASK(5, 3)
 #define MT_EE_WIFI_CONF2_TX_PATH_BAND1		GENMASK(2, 0)
 #define MT_EE_WIFI_CONF2_TX_PATH_BAND2		GENMASK(5, 3)
+#define MT_EE_WIFI_CONF3_RX_PATH_BAND0		GENMASK(2, 0)
+#define MT_EE_WIFI_CONF3_RX_PATH_BAND1		GENMASK(5, 3)
+#define MT_EE_WIFI_CONF4_RX_PATH_BAND2		GENMASK(2, 0)
 #define MT_EE_WIFI_CONF4_STREAM_NUM_BAND0	GENMASK(5, 3)
 #define MT_EE_WIFI_CONF5_STREAM_NUM_BAND1	GENMASK(2, 0)
 #define MT_EE_WIFI_CONF5_STREAM_NUM_BAND2	GENMASK(5, 3)

drivers/net/wireless/mediatek/mt76/mt7996/mcu.c

@@ -3299,7 +3299,7 @@ int mt7996_mcu_set_chan_info(struct mt7996_phy *phy, u16 tag)
 		.center_ch = ieee80211_frequency_to_channel(freq1),
 		.bw = mt76_connac_chan_bw(chandef),
 		.tx_path_num = hweight16(phy->mt76->chainmask),
-		.rx_path = phy->mt76->chainmask >> dev->chainshift[band_idx],
+		.rx_path = mt7996_rx_chainmask(phy) >> dev->chainshift[band_idx],
 		.band_idx = band_idx,
 		.channel_band = ch_band[chandef->chan->band],
 	};

drivers/net/wireless/mediatek/mt76/mt7996/mt7996.h

@@ -210,6 +210,8 @@ struct mt7996_phy {
 
 	struct mt76_mib_stats mib;
 	struct mt76_channel_state state_ts;
+
+	bool has_aux_rx;
 };
 
 struct mt7996_dev {
@@ -501,6 +503,18 @@ static inline void mt7996_irq_disable(struct mt7996_dev *dev, u32 mask)
 void mt7996_memcpy_fromio(struct mt7996_dev *dev, void *buf, u32 offset,
 			  size_t len);
 
+static inline u16 mt7996_rx_chainmask(struct mt7996_phy *phy)
+{
+	int max_nss = hweight8(phy->mt76->hw->wiphy->available_antennas_tx);
+	int cur_nss = hweight8(phy->mt76->antenna_mask);
+	u16 tx_chainmask = phy->mt76->chainmask;
+
+	if (cur_nss != max_nss)
+		return tx_chainmask;
+
+	return tx_chainmask | (BIT(fls(tx_chainmask)) * phy->has_aux_rx);
+}
+
 void mt7996_mac_init(struct mt7996_dev *dev);
 u32 mt7996_mac_wtbl_lmac_addr(struct mt7996_dev *dev, u16 wcid, u8 dw);
 bool mt7996_mac_wtbl_update(struct mt7996_dev *dev, int idx, u32 mask);