mmc: fsl_esdhc: Add support for DDR mode

Add support of the DDR mode for eSDHC driver.
Enable it for i.MX6 SoC family only.

Signed-off-by: Volodymyr Riazantsev <volodymyr.riazantsev@globallogic.com>
Reviewed-by: York Sun <yorksun@freescale.com>

drivers/mmc/fsl_esdhc.c

@@ -319,7 +319,8 @@ esdhc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd, struct mmc_data *data)
 	esdhc_write32(&regs->cmdarg, cmd->cmdarg);
 #if defined(CONFIG_FSL_USDHC)
 	esdhc_write32(&regs->mixctrl,
-	(esdhc_read32(&regs->mixctrl) & 0xFFFFFF80) | (xfertyp & 0x7F));
+	(esdhc_read32(&regs->mixctrl) & 0xFFFFFF80) | (xfertyp & 0x7F)
+			| (mmc->ddr_mode ? XFERTYP_DDREN : 0));
 	esdhc_write32(&regs->xfertyp, xfertyp & 0xFFFF0000);
 #else
 	esdhc_write32(&regs->xfertyp, xfertyp);
@@ -442,7 +443,7 @@ static void set_sysctl(struct mmc *mmc, uint clock)
 		if ((sdhc_clk / (div * pre_div)) <= clock)
 			break;
 
-	pre_div >>= 1;
+	pre_div >>= mmc->ddr_mode ? 2 : 1;
 	div -= 1;
 
 	clk = (pre_div << 8) | (div << 4);
@@ -601,6 +602,9 @@ int fsl_esdhc_initialize(bd_t *bis, struct fsl_esdhc_cfg *cfg)
 	}
 
 	cfg->cfg.host_caps = MMC_MODE_4BIT | MMC_MODE_8BIT | MMC_MODE_HC;
+#ifdef CONFIG_SYS_FSL_ESDHC_HAS_DDR_MODE
+	cfg->cfg.host_caps |= MMC_MODE_DDR_52MHz;
+#endif
 
 	if (cfg->max_bus_width > 0) {
 		if (cfg->max_bus_width < 8)

include/configs/mx6_common.h

@@ -28,6 +28,8 @@
 #define CONFIG_SYS_PL310_BASE	L2_PL310_BASE
 #endif
 
+#define CONFIG_SYS_FSL_ESDHC_HAS_DDR_MODE
+
 #define CONFIG_MP
 #define CONFIG_MXC_GPT_HCLK
 

include/fsl_esdhc.h

@@ -108,6 +108,7 @@
 #define XFERTYP_RSPTYP_48_BUSY	0x00030000
 #define XFERTYP_MSBSEL		0x00000020
 #define XFERTYP_DTDSEL		0x00000010
+#define XFERTYP_DDREN		0x00000008
 #define XFERTYP_AC12EN		0x00000004
 #define XFERTYP_BCEN		0x00000002
 #define XFERTYP_DMAEN		0x00000001