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>
Signed-off-by: Chris Ball <chris@printf.net>
diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index fd4aab9..2f8a57d 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -710,3 +710,10 @@
 	help
 	  Say Y here to include driver code to support SD/MMC card interface
 	  of Realtek RTS5129/39 series 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.