wifi: rtw88: 8821c: tweak CCK TX filter setting for SRRC regulation

Since new criterion released by SRRC (State Radio Regulatory Commission,
China) is stricter, we have adjusted TX power limit tables for it. But,
due to RTL8821C HW characteristic, we still need to use specific parameter
in CCK TX filter when set channel to avoid violations in some corner cases.
Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231004085051.205683-6-pkshih@realtek.com

drivers/net/wireless/realtek/rtw88/regd.c

@@ -502,6 +502,14 @@ u8 rtw_regd_get(struct rtw_dev *rtwdev)
 }
 EXPORT_SYMBOL(rtw_regd_get);
 
+bool rtw_regd_srrc(struct rtw_dev *rtwdev)
+{
+	struct rtw_regd *regd = &rtwdev->regd;
+
+	return rtw_reg_match(regd->regulatory, "CN");
+}
+EXPORT_SYMBOL(rtw_regd_srrc);
+
 struct rtw_regd_alternative_t {
 	bool set;
 	u8 alt;

drivers/net/wireless/realtek/rtw88/regd.h

@@ -68,4 +68,6 @@ int rtw_regd_init(struct rtw_dev *rtwdev);
 int rtw_regd_hint(struct rtw_dev *rtwdev);
 u8 rtw_regd_get(struct rtw_dev *rtwdev);
 bool rtw_regd_has_alt(u8 regd, u8 *regd_alt);
+bool rtw_regd_srrc(struct rtw_dev *rtwdev);
+
 #endif

drivers/net/wireless/realtek/rtw88/rtw8821c.c

@@ -381,6 +381,65 @@ static void rtw8821c_set_channel_rxdfir(struct rtw_dev *rtwdev, u8 bw)
 	}
 }
 
+static void rtw8821c_cck_tx_filter_srrc(struct rtw_dev *rtwdev, u8 channel, u8 bw)
+{
+	struct rtw_hal *hal = &rtwdev->hal;
+
+	if (channel == 14) {
+		rtw_write32_mask(rtwdev, REG_CCA_FLTR, MASKHWORD, 0xe82c);
+		rtw_write32_mask(rtwdev, REG_TXSF2, MASKDWORD, 0x0000b81c);
+		rtw_write32_mask(rtwdev, REG_TXSF6, MASKLWORD, 0x0000);
+		rtw_write32_mask(rtwdev, REG_TXFILTER, MASKDWORD, 0x00003667);
+
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWE2, RFREG_MASK, 0x00002);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWA, RFREG_MASK, 0x0001e);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWD0, RFREG_MASK, 0x00000);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWA, RFREG_MASK, 0x0001c);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWD0, RFREG_MASK, 0x00000);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWA, RFREG_MASK, 0x0000e);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWD0, RFREG_MASK, 0x00000);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWA, RFREG_MASK, 0x0000c);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWD0, RFREG_MASK, 0x00000);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWE2, RFREG_MASK, 0x00000);
+	} else if (channel == 13 ||
+		   (channel == 11 && bw == RTW_CHANNEL_WIDTH_40)) {
+		rtw_write32_mask(rtwdev, REG_CCA_FLTR, MASKHWORD, 0xf8fe);
+		rtw_write32_mask(rtwdev, REG_TXSF2, MASKDWORD, 0x64b80c1c);
+		rtw_write32_mask(rtwdev, REG_TXSF6, MASKLWORD, 0x8810);
+		rtw_write32_mask(rtwdev, REG_TXFILTER, MASKDWORD, 0x01235667);
+
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWE2, RFREG_MASK, 0x00002);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWA, RFREG_MASK, 0x0001e);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWD0, RFREG_MASK, 0x00027);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWA, RFREG_MASK, 0x0001c);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWD0, RFREG_MASK, 0x00027);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWA, RFREG_MASK, 0x0000e);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWD0, RFREG_MASK, 0x00029);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWA, RFREG_MASK, 0x0000c);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWD0, RFREG_MASK, 0x00026);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWE2, RFREG_MASK, 0x00000);
+	} else {
+		rtw_write32_mask(rtwdev, REG_CCA_FLTR, MASKHWORD, 0xe82c);
+		rtw_write32_mask(rtwdev, REG_TXSF2, MASKDWORD,
+				 hal->ch_param[0]);
+		rtw_write32_mask(rtwdev, REG_TXSF6, MASKLWORD,
+				 hal->ch_param[1] & MASKLWORD);
+		rtw_write32_mask(rtwdev, REG_TXFILTER, MASKDWORD,
+				 hal->ch_param[2]);
+
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWE2, RFREG_MASK, 0x00002);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWA, RFREG_MASK, 0x0001e);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWD0, RFREG_MASK, 0x00000);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWA, RFREG_MASK, 0x0001c);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWD0, RFREG_MASK, 0x00000);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWA, RFREG_MASK, 0x0000e);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWD0, RFREG_MASK, 0x00000);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWA, RFREG_MASK, 0x0000c);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWD0, RFREG_MASK, 0x00000);
+		rtw_write_rf(rtwdev, RF_PATH_A, RF_LUTWE2, RFREG_MASK, 0x00000);
+	}
+}
+
 static void rtw8821c_set_channel_bb(struct rtw_dev *rtwdev, u8 channel, u8 bw,
 				    u8 primary_ch_idx)
 {
@@ -395,6 +454,13 @@ static void rtw8821c_set_channel_bb(struct rtw_dev *rtwdev, u8 channel, u8 bw,
 
 		rtw_write32_mask(rtwdev, REG_TXSCALE_A, 0xf00, 0x0);
 		rtw_write32_mask(rtwdev, REG_CLKTRK, 0x1ffe0000, 0x96a);
+
+		if (rtw_regd_srrc(rtwdev)) {
+			rtw8821c_cck_tx_filter_srrc(rtwdev, channel, bw);
+			goto set_bw;
+		}
+
+		/* CCK TX filter parameters for default case */
 		if (channel == 14) {
 			rtw_write32_mask(rtwdev, REG_TXSF2, MASKDWORD, 0x0000b81c);
 			rtw_write32_mask(rtwdev, REG_TXSF6, MASKLWORD, 0x0000);
@@ -430,6 +496,7 @@ static void rtw8821c_set_channel_bb(struct rtw_dev *rtwdev, u8 channel, u8 bw,
 			rtw_write32_mask(rtwdev, REG_CLKTRK, 0x1ffe0000, 0x412);
 	}
 
+set_bw:
 	switch (bw) {
 	case RTW_CHANNEL_WIDTH_20:
 	default:

drivers/net/wireless/realtek/rtw88/rtw8821c.h

@@ -238,6 +238,7 @@ extern const struct rtw_chip_info rtw8821c_hw_spec;
 #define REG_RXSB	0xa00
 #define REG_ADCINI	0xa04
 #define REG_PWRTH	0xa08
+#define REG_CCA_FLTR	0xa20
 #define REG_TXSF2	0xa24
 #define REG_TXSF6	0xa28
 #define REG_FA_CCK	0xa5c