mmc: mediatek: Add Mediatek MMC driver

Add Mediatek MMC driver code
Support eMMC/SD/SDIO
Signed-off-by: Chaotian Jing <chaotian.jing@mediatek.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/Kconfig

@@ -776,3 +776,11 @@ config MMC_TOSHIBA_PCI
 	tristate "Toshiba Type A SD/MMC Card Interface Driver"
 	depends on PCI
 	help
+
+config MMC_MTK
+	tristate "MediaTek SD/MMC Card Interface support"
+	help
+	  This selects the MediaTek(R) Secure digital and Multimedia card Interface.
+	  If you have a machine with a integrated SD/MMC card reader, say Y or M here.
+	  This is needed if support for any SD/SDIO/MMC devices is required.
+	  If unsure, say N.

drivers/mmc/host/Makefile

@@ -20,6 +20,7 @@ obj-$(CONFIG_MMC_SDHCI_F_SDH30)	+= sdhci_f_sdh30.o
 obj-$(CONFIG_MMC_SDHCI_SPEAR)	+= sdhci-spear.o
 obj-$(CONFIG_MMC_WBSD)		+= wbsd.o
 obj-$(CONFIG_MMC_AU1X)		+= au1xmmc.o
+obj-$(CONFIG_MMC_MTK)		+= mtk-sd.o
 obj-$(CONFIG_MMC_OMAP)		+= omap.o
 obj-$(CONFIG_MMC_OMAP_HS)	+= omap_hsmmc.o
 obj-$(CONFIG_MMC_ATMELMCI)	+= atmel-mci.o

include/linux/mmc/core.h

@@ -121,6 +121,7 @@ struct mmc_data {
 	struct mmc_request	*mrq;		/* associated request */
 
 	unsigned int		sg_len;		/* size of scatter list */
+	int			sg_count;	/* mapped sg entries */
 	struct scatterlist	*sg;		/* I/O scatter list */
 	s32			host_cookie;	/* host private data */
 };