mmc: loongson2: Add Loongson-2K SD/SDIO controller driver

The MMC controllers on the Loongson-2K series CPUs are similar,
except for the interface characteristics and the use of DMA controllers.

This patch describes the MMC controllers on the Loongson-2K0500/2K1000,
with the distinguishing feature being the use of an externally shared
APBDMA engine.

Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Link: https://lore.kernel.org/r/c0a9f0c0279d8e09165c6e2d694b0c35f7fc7e31.1750765495.git.zhoubinbin@loongson.cn
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Author: AaronDot

MAINTAINERS

@@ -14180,6 +14180,7 @@ M:	Binbin Zhou <zhoubinbin@loongson.cn>
 L:	linux-mmc@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/mmc/loongson,ls2k0500-mmc.yaml
+F:	drivers/mmc/host/loongson2-mmc.c
 
 LOONGSON-2 SOC SERIES PM DRIVER
 M:	Yinbo Zhu <zhuyinbo@loongson.cn>

drivers/mmc/host/Kconfig

@@ -1111,6 +1111,19 @@ config MMC_OWL
 	  This selects support for the SD/MMC Host Controller on
 	  Actions Semi Owl SoCs.
 
+config MMC_LOONGSON2
+	tristate "Loongson-2K SD/SDIO/eMMC Host Interface support"
+	depends on LOONGARCH || COMPILE_TEST
+	depends on HAS_DMA
+	help
+	  This selects support for the SD/SDIO/eMMC Host Controller on
+	  Loongson-2K series CPUs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called mmc_loongson2.
+
+	  If unsure, say N.
+
 config MMC_SDHCI_EXTERNAL_DMA
 	bool
 

drivers/mmc/host/Makefile

@@ -72,6 +72,7 @@ obj-$(CONFIG_MMC_USDHI6ROL0)	+= usdhi6rol0.o
 obj-$(CONFIG_MMC_TOSHIBA_PCI)	+= toshsd.o
 obj-$(CONFIG_MMC_BCM2835)	+= bcm2835.o
 obj-$(CONFIG_MMC_OWL)		+= owl-mmc.o
+obj-$(CONFIG_MMC_LOONGSON2)	+= loongson2-mmc.o
 
 obj-$(CONFIG_MMC_REALTEK_PCI)	+= rtsx_pci_sdmmc.o
 obj-$(CONFIG_MMC_REALTEK_USB)	+= rtsx_usb_sdmmc.o