wifi: rtw88: sdio: Add HCI implementation for SDIO based chipsets

Add a sub-driver for SDIO based chipsets which implements the following
functionality:
- register accessors for 8, 16 and 32 bits for all states of the card
  (including usage of 4x 8 bit access for one 32 bit buffer if the card
  is not fully powered on yet - or if it's fully powered on then 1x 32
  bit access is used)
- checking whether there's space in the TX FIFO queue to transmit data
- transfers from the host to the device for actual network traffic,
  reserved pages (for firmware download) and H2C (host-to-card)
  transfers
- receiving data from the device
- deep power saving state

The transmit path is optimized so DMA-capable SDIO host controllers can
directly use the buffers provided because the buffer's physical
addresses are 8 byte aligned.

The receive path is prepared to support RX aggregation where the
chipset combines multiple MAC frames into one bigger buffer to reduce
SDIO transfer overhead.

Co-developed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230405200729.632435-3-martin.blumenstingl@googlemail.com

drivers/net/wireless/realtek/rtw88/Kconfig

@@ -16,6 +16,9 @@ config RTW88_CORE
 config RTW88_PCI
 	tristate
 
+config RTW88_SDIO
+	tristate
+
 config RTW88_USB
 	tristate
 

drivers/net/wireless/realtek/rtw88/Makefile

@@ -59,5 +59,8 @@ rtw88_8821cu-objs		:= rtw8821cu.o
 obj-$(CONFIG_RTW88_PCI)		+= rtw88_pci.o
 rtw88_pci-objs			:= pci.o
 
+obj-$(CONFIG_RTW88_SDIO)	+= rtw88_sdio.o
+rtw88_sdio-objs			:= sdio.o
+
 obj-$(CONFIG_RTW88_USB)		+= rtw88_usb.o
 rtw88_usb-objs			:= usb.o

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

@@ -24,6 +24,7 @@ enum rtw_debug_mask {
 	RTW_DBG_ADAPTIVITY	= 0x00008000,
 	RTW_DBG_HW_SCAN		= 0x00010000,
 	RTW_DBG_STATE		= 0x00020000,
+	RTW_DBG_SDIO		= 0x00040000,
 
 	RTW_DBG_ALL		= 0xffffffff
 };

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

@@ -7,6 +7,7 @@
 #include "reg.h"
 #include "fw.h"
 #include "debug.h"
+#include "sdio.h"
 
 void rtw_set_channel_mac(struct rtw_dev *rtwdev, u8 channel, u8 bw,
 			 u8 primary_ch_idx)

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

@@ -7,7 +7,6 @@
 
 #define RTW_HW_PORT_NUM		5
 #define cut_version_to_mask(cut) (0x1 << ((cut) + 1))
-#define SDIO_LOCAL_OFFSET	0x10250000
 #define DDMA_POLLING_COUNT	1000
 #define C2H_PKT_BUF		256
 #define REPORT_BUF		128

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

@@ -87,6 +87,7 @@
 #define BIT_LTE_MUX_CTRL_PATH	BIT(26)
 #define REG_HCI_OPT_CTRL	0x0074
 #define BIT_USB_SUS_DIS		BIT(8)
+#define BIT_SDIO_PAD_E5		BIT(18)
 
 #define REG_AFE_CTRL_4		0x0078
 #define BIT_CK320M_AFE_EN	BIT(4)
@@ -185,6 +186,9 @@
 	(((x) & BIT_MASK_TXDMA_VIQ_MAP) << BIT_SHIFT_TXDMA_VIQ_MAP)
 #define REG_TXDMA_PQ_MAP	0x010C
 #define BIT_RXDMA_ARBBW_EN	BIT(0)
+#define BIT_RXSHFT_EN		BIT(1)
+#define BIT_RXDMA_AGG_EN	BIT(2)
+#define BIT_TXDMA_BW_EN		BIT(3)
 #define BIT_SHIFT_TXDMA_BEQ_MAP	8
 #define BIT_MASK_TXDMA_BEQ_MAP	0x3
 #define BIT_TXDMA_BEQ_MAP(x)                                                   \
@@ -283,10 +287,18 @@
 #define REG_H2C_TAIL		0x0248
 #define REG_H2C_READ_ADDR	0x024C
 #define REG_H2C_INFO		0x0254
+#define REG_RXDMA_AGG_PG_TH	0x0280
+#define BIT_RXDMA_AGG_PG_TH	GENMASK(7, 0)
+#define BIT_DMA_AGG_TO_V1	GENMASK(15, 8)
+#define BIT_EN_PRE_CALC		BIT(29)
 #define REG_RXPKT_NUM		0x0284
 #define BIT_RXDMA_REQ		BIT(19)
 #define BIT_RW_RELEASE		BIT(18)
 #define BIT_RXDMA_IDLE		BIT(17)
+#define REG_RXDMA_STATUS	0x0288
+#define REG_RXDMA_DPR		0x028C
+#define REG_RXDMA_MODE		0x0290
+#define BIT_DMA_MODE		BIT(1)
 #define REG_RXPKTNUM		0x02B0
 
 #define REG_INT_MIG		0x0304