wifi: rtw88: usb: Support USB 3 with RTL8822CU/RTL8822BU

The Realtek wifi 5 devices which support USB 3 are weird: when first
plugged in, they pretend to be USB 2. The driver needs to send some
commands to the device, which make it disappear and come back as a
USB 3 device.

Implement the required commands in rtw88.

When a USB 3 device is plugged into a USB 2 port, rtw88 will try to
switch it to USB 3 mode only once. The device will disappear and come
back still in USB 2 mode, of course.

Some people experience heavy interference in the 2.4 GHz band in
USB 3 mode, so add a module parameter switch_usb_mode with the
default value 1 to let people disable the switching.

Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/77906c62-5674-426f-bde1-1b2a12a0339d@gmail.com

8 files changed, 116 insertions, 12 deletions

diff --git a/drivers/net/wireless/realtek/rtw88/debug.h b/drivers/net/wireless/realtek/rtw88/debug.h
index eb69006c463e..9a1e0e85a13c 100644
--- a/drivers/net/wireless/realtek/rtw88/debug.h
+++ b/drivers/net/wireless/realtek/rtw88/debug.h
@@ -25,6 +25,7 @@ enum rtw_debug_mask {
 	RTW_DBG_HW_SCAN		= 0x00010000,
 	RTW_DBG_STATE		= 0x00020000,
 	RTW_DBG_SDIO		= 0x00040000,
+	RTW_DBG_USB		= 0x00080000,
 
 	RTW_DBG_UNEXP		= 0x80000000,
 	RTW_DBG_ALL		= 0xffffffff
diff --git a/drivers/net/wireless/realtek/rtw88/main.h b/drivers/net/wireless/realtek/rtw88/main.h
index 49a3fd4fb7dc..9d21637cf5d5 100644
--- a/drivers/net/wireless/realtek/rtw88/main.h
+++ b/drivers/net/wireless/realtek/rtw88/main.h
@@ -1785,6 +1785,8 @@ struct rtw_efuse {
 	bool share_ant;
 	u8 bt_setting;
 
+	u8 usb_mode_switch;
+
 	struct {
 		u8 hci;
 		u8 bw;
diff --git a/drivers/net/wireless/realtek/rtw88/reg.h b/drivers/net/wireless/realtek/rtw88/reg.h
index 02ef9a77316b..e7b24465f549 100644
--- a/drivers/net/wireless/realtek/rtw88/reg.h
+++ b/drivers/net/wireless/realtek/rtw88/reg.h
@@ -15,6 +15,7 @@
 #define BIT_WLOCK_1C_B6		BIT(5)
 #define REG_SYS_PW_CTRL		0x0004
 #define BIT_PFM_WOWL		BIT(3)
+#define BIT_APFM_OFFMAC		BIT(9)
 #define REG_SYS_CLK_CTRL	0x0008
 #define BIT_CPU_CLK_EN		BIT(14)
 
@@ -133,6 +134,14 @@
 #define REG_PMC_DBG_CTRL1	0xa8
 #define BITS_PMC_BT_IQK_STS	GENMASK(22, 21)
 
+#define REG_PAD_CTRL2		0x00C4
+#define BIT_RSM_EN_V1		BIT(16)
+#define BIT_NO_PDN_CHIPOFF_V1	BIT(17)
+#define BIT_MASK_USB23_SW_MODE_V1	GENMASK(19, 18)
+#define BIT_USB3_USB2_TRANSITION	BIT(20)
+#define BIT_USB_MODE_U2		1
+#define BIT_USB_MODE_U3		2
+
 #define REG_EFUSE_ACCESS	0x00CF
 #define EFUSE_ACCESS_ON		0x69
 #define EFUSE_ACCESS_OFF	0x00
@@ -568,6 +577,8 @@
 #define BIT_WL_SECURITY_CLK	BIT(15)
 #define BIT_DDMA_EN		BIT(8)
 
+#define REG_SW_MDIO		0x10C0
+
 #define REG_H2C_PKT_READADDR	0x10D0
 #define REG_H2C_PKT_WRITEADDR	0x10D4
 #define REG_FW_DBG6		0x10F8
diff --git a/drivers/net/wireless/realtek/rtw88/rtw8822b.c b/drivers/net/wireless/realtek/rtw88/rtw8822b.c
index 2456ff242818..6edb17aea90e 100644
--- a/drivers/net/wireless/realtek/rtw88/rtw8822b.c
+++ b/drivers/net/wireless/realtek/rtw88/rtw8822b.c
@@ -46,6 +46,7 @@ static int rtw8822b_read_efuse(struct rtw_dev *rtwdev, u8 *log_map)
 
 	map = (struct rtw8822b_efuse *)log_map;
 
+	efuse->usb_mode_switch = u8_get_bits(map->usb_mode, BIT(7));
 	efuse->rfe_option = map->rfe_option;
 	efuse->rf_board_option = map->rf_board_option;
 	efuse->crystal_cap = map->xtal_k;
diff --git a/drivers/net/wireless/realtek/rtw88/rtw8822b.h b/drivers/net/wireless/realtek/rtw88/rtw8822b.h
index 2dc3a6660f06..cf85e63966a1 100644
--- a/drivers/net/wireless/realtek/rtw88/rtw8822b.h
+++ b/drivers/net/wireless/realtek/rtw88/rtw8822b.h
@@ -72,7 +72,9 @@ struct rtw8822bs_efuse {
 
 struct rtw8822b_efuse {
 	__le16 rtl_id;
-	u8 res0[0x0e];
+	u8 res0[4];
+	u8 usb_mode;
+	u8 res1[0x09];
 
 	/* power index for four RF paths */
 	struct rtw_txpwr_idx txpwr_idx_table[4];
diff --git a/drivers/net/wireless/realtek/rtw88/rtw8822c.c b/drivers/net/wireless/realtek/rtw88/rtw8822c.c
index 62376d1cca22..bc807b13e9ce 100644
--- a/drivers/net/wireless/realtek/rtw88/rtw8822c.c
+++ b/drivers/net/wireless/realtek/rtw88/rtw8822c.c
@@ -49,6 +49,7 @@ static int rtw8822c_read_efuse(struct rtw_dev *rtwdev, u8 *log_map)
 
 	map = (struct rtw8822c_efuse *)log_map;
 
+	efuse->usb_mode_switch = u8_get_bits(map->usb_mode, BIT(7));
 	efuse->rfe_option = map->rfe_option;
 	efuse->rf_board_option = map->rf_board_option;
 	efuse->crystal_cap = map->xtal_k & XCAP_MASK;
diff --git a/drivers/net/wireless/realtek/rtw88/rtw8822c.h b/drivers/net/wireless/realtek/rtw88/rtw8822c.h
index 1bc0e7f5d6bb..e2b383d633cd 100644
--- a/drivers/net/wireless/realtek/rtw88/rtw8822c.h
+++ b/drivers/net/wireless/realtek/rtw88/rtw8822c.h
@@ -59,16 +59,18 @@ struct rtw8822ce_efuse {
 
 struct rtw8822c_efuse {
 	__le16 rtl_id;
-	u8 res0[0x0e];
+	u8 res0[4];
+	u8 usb_mode;
+	u8 res1[0x09];
 
 	/* power index for four RF paths */
 	struct rtw_txpwr_idx txpwr_idx_table[4];
 
 	u8 channel_plan;		/* 0xb8 */
 	u8 xtal_k;
-	u8 res1;
+	u8 res2;
 	u8 iqk_lck;
-	u8 res2[5];			/* 0xbc */
+	u8 res3[5];			/* 0xbc */
 	u8 rf_board_option;
 	u8 rf_feature_option;
 	u8 rf_bt_setting;
@@ -80,21 +82,21 @@ struct rtw8822c_efuse {
 	u8 rf_antenna_option;		/* 0xc9 */
 	u8 rfe_option;
 	u8 country_code[2];
-	u8 res3[3];
+	u8 res4[3];
 	u8 path_a_thermal;		/* 0xd0 */
 	u8 path_b_thermal;
-	u8 res4[2];
+	u8 res5[2];
 	u8 rx_gain_gap_2g_ofdm;
-	u8 res5;
-	u8 rx_gain_gap_2g_cck;
 	u8 res6;
-	u8 rx_gain_gap_5gl;
+	u8 rx_gain_gap_2g_cck;
 	u8 res7;
-	u8 rx_gain_gap_5gm;
+	u8 rx_gain_gap_5gl;
 	u8 res8;
-	u8 rx_gain_gap_5gh;
+	u8 rx_gain_gap_5gm;
 	u8 res9;
-	u8 res10[0x42];
+	u8 rx_gain_gap_5gh;
+	u8 res10;
+	u8 res11[0x42];
 	union {
 		struct rtw8822ce_efuse e;
 		struct rtw8822cu_efuse u;
diff --git a/drivers/net/wireless/realtek/rtw88/usb.c b/drivers/net/wireless/realtek/rtw88/usb.c
index a55ca5a24227..251a5726f3ee 100644
--- a/drivers/net/wireless/realtek/rtw88/usb.c
+++ b/drivers/net/wireless/realtek/rtw88/usb.c
@@ -14,6 +14,11 @@
 #include "ps.h"
 #include "usb.h"
 
+static bool rtw_switch_usb_mode = true;
+module_param_named(switch_usb_mode, rtw_switch_usb_mode, bool, 0644);
+MODULE_PARM_DESC(switch_usb_mode,
+		 "Set to N to disable switching to USB 3 mode to avoid potential interference in the 2.4 GHz band (default: Y)");
+
 #define RTW_USB_MAX_RXQ_LEN	512
 
 struct rtw_usb_txcb {
@@ -841,6 +846,77 @@ static void rtw_usb_intf_deinit(struct rtw_dev *rtwdev,
 	usb_set_intfdata(intf, NULL);
 }
 
+static int rtw_usb_switch_mode_new(struct rtw_dev *rtwdev)
+{
+	enum usb_device_speed cur_speed;
+	u8 id = rtwdev->chip->id;
+	bool can_switch;
+	u32 pad_ctrl2;
+
+	if (rtw_read8(rtwdev, REG_SYS_CFG2 + 3) == 0x20)
+		cur_speed = USB_SPEED_SUPER;
+	else
+		cur_speed = USB_SPEED_HIGH;
+
+	if (cur_speed == USB_SPEED_SUPER)
+		return 0;
+
+	pad_ctrl2 = rtw_read32(rtwdev, REG_PAD_CTRL2);
+
+	can_switch = !!(pad_ctrl2 & (BIT_MASK_USB23_SW_MODE_V1 |
+				     BIT_USB3_USB2_TRANSITION));
+
+	if (!can_switch) {
+		rtw_dbg(rtwdev, RTW_DBG_USB,
+			"Switching to USB 3 mode unsupported by the chip\n");
+		return 0;
+	}
+
+	/* At this point cur_speed is USB_SPEED_HIGH. If we already tried
+	 * to switch don't try again - it's a USB 2 port.
+	 */
+	if (u32_get_bits(pad_ctrl2, BIT_MASK_USB23_SW_MODE_V1) == BIT_USB_MODE_U3)
+		return 0;
+
+	/* Enable IO wrapper timeout */
+	if (id == RTW_CHIP_TYPE_8822B || id == RTW_CHIP_TYPE_8821C)
+		rtw_write8_clr(rtwdev, REG_SW_MDIO + 3, BIT(0));
+
+	u32p_replace_bits(&pad_ctrl2, BIT_USB_MODE_U3, BIT_MASK_USB23_SW_MODE_V1);
+	pad_ctrl2 |= BIT_RSM_EN_V1;
+
+	rtw_write32(rtwdev, REG_PAD_CTRL2, pad_ctrl2);
+	rtw_write8(rtwdev, REG_PAD_CTRL2 + 1, 4);
+
+	rtw_write16_set(rtwdev, REG_SYS_PW_CTRL, BIT_APFM_OFFMAC);
+	usleep_range(1000, 1001);
+	rtw_write32_set(rtwdev, REG_PAD_CTRL2, BIT_NO_PDN_CHIPOFF_V1);
+
+	return 1;
+}
+
+static int rtw_usb_switch_mode(struct rtw_dev *rtwdev)
+{
+	u8 id = rtwdev->chip->id;
+
+	if (id != RTW_CHIP_TYPE_8822C && id != RTW_CHIP_TYPE_8822B)
+		return 0;
+
+	if (!rtwdev->efuse.usb_mode_switch) {
+		rtw_dbg(rtwdev, RTW_DBG_USB,
+			"Switching to USB 3 mode disabled by chip's efuse\n");
+		return 0;
+	}
+
+	if (!rtw_switch_usb_mode) {
+		rtw_dbg(rtwdev, RTW_DBG_USB,
+			"Switching to USB 3 mode disabled by module parameter\n");
+		return 0;
+	}
+
+	return rtw_usb_switch_mode_new(rtwdev);
+}
+
 int rtw_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
 {
 	struct rtw_dev *rtwdev;
@@ -896,6 +972,14 @@ int rtw_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
 		goto err_destroy_rxwq;
 	}
 
+	ret = rtw_usb_switch_mode(rtwdev);
+	if (ret) {
+		/* Not a fail, but we do need to skip rtw_register_hw. */
+		rtw_dbg(rtwdev, RTW_DBG_USB, "switching to USB 3 mode\n");
+		ret = 0;
+		goto err_destroy_rxwq;
+	}
+
 	ret = rtw_register_hw(rtwdev, rtwdev->hw);
 	if (ret) {
 		rtw_err(rtwdev, "failed to register hw\n");