wifi: rtw89: 8852c: enable the interference cancellation of MU-MIMO on 6GHz

Enable MU-MIMO interference cancellation (MUIC) to yield expected
performance of receiving MU-MIMO packets on 6GHz.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220908051257.25353-3-pkshih@realtek.com

drivers/net/wireless/realtek/rtw89/reg.h

@@ -3680,6 +3680,8 @@
 #define R_S1_ADDCK 0x3E00
 #define B_S1_ADDCK_I GENMASK(9, 0)
 #define B_S1_ADDCK_Q GENMASK(19, 10)
+#define R_MUIC 0x40F8
+#define B_MUIC_EN BIT(0)
 #define R_DCFO 0x4264
 #define B_DCFO GENMASK(1, 0)
 #define R_SEG0CSI 0x42AC

drivers/net/wireless/realtek/rtw89/rtw8852c.c

@@ -1791,6 +1791,11 @@ static void rtw8852c_set_channel_bb(struct rtw89_dev *rtwdev,
 		}
 	}
 
+	if (chan->band_type == RTW89_BAND_6G)
+		rtw89_phy_write32_set(rtwdev, R_MUIC, B_MUIC_EN);
+	else
+		rtw89_phy_write32_clr(rtwdev, R_MUIC, B_MUIC_EN);
+
 	rtw8852c_bb_reset_all(rtwdev, phy_idx);
 }