mmc: dw_mmc: support DDR mode

This patch adds DDR mode support to dw_mmc.

If we set any bit in UHS_REG bit[16:31], the card of that slot is
supported for DDR mode.  For example, if UHS_REG[16] is set, card
number 0 is DDR mode.
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Will Newton <will.newton@imgtec.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/host/dw_mmc.c

@@ -662,6 +662,7 @@ static void dw_mci_request(struct mmc_host *mmc, struct mmc_request *mrq)
 static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 {
 	struct dw_mci_slot *slot = mmc_priv(mmc);
+	u32 regs;
 
 	/* set default 1 bit mode */
 	slot->ctype = SDMMC_CTYPE_1BIT;
@@ -678,6 +679,13 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 		break;
 	}
 
+	/* DDR mode set */
+	if (ios->ddr) {
+		regs = mci_readl(slot->host, UHS_REG);
+		regs |= (0x1 << slot->id) << 16;
+		mci_writel(slot->host, UHS_REG, regs);
+	}
+
 	if (ios->clock) {
 		/*
 		 * Use mirror of ios->clock to prevent race with mmc

drivers/mmc/host/dw_mmc.h

@@ -43,6 +43,7 @@
 #define SDMMC_USRID		0x068
 #define SDMMC_VERID		0x06c
 #define SDMMC_HCON		0x070
+#define SDMMC_UHS_REG		0x074
 #define SDMMC_BMOD		0x080
 #define SDMMC_PLDMND		0x084
 #define SDMMC_DBADDR		0x088
@@ -51,7 +52,6 @@
 #define SDMMC_DSCADDR		0x094
 #define SDMMC_BUFADDR		0x098
 #define SDMMC_DATA		0x100
-#define SDMMC_DATA_ADR		0x100
 
 /* shift bit field */
 #define _SBF(f, v)		((v) << (f))