mmc: sunxi: Add driver for SD/MMC hosts found on Allwinner sunxi SoCs

The Allwinner sunxi mmc host uses dma in bus-master mode using a built-in
designware idmac controller, which is identical to the one found in the mmc-dw
hosts. However the rest of the host is not identical to mmc-dw, it deals with
sending stop commands in hardware which makes it significantly different
from the mmc-dw devices.

Signed-off-by: David Lanzendörfer <david.lanzendoerfer@o2s.ch>
[hdegoede@redhat.com: various cleanups and fixes]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Chris Ball <chris@printf.net>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

Documentation/devicetree/bindings/mmc/sunxi-mmc.txt

@@ -0,0 +1,43 @@
+* Allwinner sunxi MMC controller
+
+The highspeed MMC host controller on Allwinner SoCs provides an interface
+for MMC, SD and SDIO types of memory cards.
+
+Supported maximum speeds are the ones of the eMMC standard 4.5 as well
+as the speed of SD standard 3.0.
+Absolute maximum transfer rate is 200MB/s
+
+Required properties:
+ - compatible : "allwinner,sun4i-a10-mmc" or "allwinner,sun5i-a13-mmc"
+ - reg : mmc controller base registers
+ - clocks : a list with 2 phandle + clock specifier pairs
+ - clock-names : must contain "ahb" and "mmc"
+ - interrupts : mmc controller interrupt
+
+Optional properties:
+ - resets : phandle + reset specifier pair
+ - reset-names : must contain "ahb"
+ - for cd, bus-width and additional generic mmc parameters
+   please refer to mmc.txt within this directory
+
+Examples:
+	- Within .dtsi:
+	mmc0: mmc@01c0f000 {
+		compatible = "allwinner,sun5i-a13-mmc";
+		reg = <0x01c0f000 0x1000>;
+		clocks = <&ahb_gates 8>, <&mmc0_clk>;
+		clock-names = "ahb", "mod";
+		interrupts = <0 32 4>;
+		status = "disabled";
+	};
+
+	- Within dts:
+	mmc0: mmc@01c0f000 {
+		pinctrl-names = "default", "default";
+		pinctrl-0 = <&mmc0_pins_a>;
+		pinctrl-1 = <&mmc0_cd_pin_reference_design>;
+		bus-width = <4>;
+		cd-gpios = <&pio 7 1 0>; /* PH1 */
+		cd-inverted;
+		status = "okay";
+	};

drivers/mmc/host/Kconfig

@@ -694,3 +694,10 @@ config MMC_REALTEK_PCI
 	help
 	  Say Y here to include driver code to support SD/MMC card interface
 	  of Realtek PCI-E card reader
+
+config MMC_SUNXI
+	tristate "Allwinner sunxi SD/MMC Host Controller support"
+	depends on ARCH_SUNXI
+	help
+	  This selects support for the SD/MMC Host Controller on
+	  Allwinner sunxi SoCs.

drivers/mmc/host/Makefile

@@ -50,6 +50,7 @@ obj-$(CONFIG_MMC_JZ4740)	+= jz4740_mmc.o
 obj-$(CONFIG_MMC_VUB300)	+= vub300.o
 obj-$(CONFIG_MMC_USHC)		+= ushc.o
 obj-$(CONFIG_MMC_WMT)		+= wmt-sdmmc.o
+obj-$(CONFIG_MMC_SUNXI)		+= sunxi-mmc.o
 
 obj-$(CONFIG_MMC_REALTEK_PCI)	+= rtsx_pci_sdmmc.o