mmc: support the DDR mode for eMMC

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Tested-by: Lukasz Majewski <l.majewski@samsung.com>
Acked-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>

drivers/mmc/mmc.c

@@ -158,6 +158,9 @@ int mmc_set_blocklen(struct mmc *mmc, int len)
 {
 	struct mmc_cmd cmd;
 
+	if (mmc->card_caps & MMC_MODE_DDR_52MHz)
+		return 0;
+
 	cmd.cmdidx = MMC_CMD_SET_BLOCKLEN;
 	cmd.resp_type = MMC_RSP_R1;
 	cmd.cmdarg = len;
@@ -514,10 +517,13 @@ static int mmc_change_freq(struct mmc *mmc)
 		return 0;
 
 	/* High Speed is set, there are two types: 52MHz and 26MHz */
-	if (cardtype & EXT_CSD_CARD_TYPE_52)
+	if (cardtype & EXT_CSD_CARD_TYPE_52) {
+		if (cardtype & EXT_CSD_CARD_TYPE_DDR_52)
+			mmc->card_caps |= MMC_MODE_DDR_52MHz;
 		mmc->card_caps |= MMC_MODE_HS_52MHz | MMC_MODE_HS;
-	else
+	} else {
 		mmc->card_caps |= MMC_MODE_HS;
+	}
 
 	return 0;
 }
@@ -1054,6 +1060,8 @@ static int mmc_startup(struct mmc *mmc)
 
 		/* An array of possible bus widths in order of preference */
 		static unsigned ext_csd_bits[] = {
+			EXT_CSD_DDR_BUS_WIDTH_8,
+			EXT_CSD_DDR_BUS_WIDTH_4,
 			EXT_CSD_BUS_WIDTH_8,
 			EXT_CSD_BUS_WIDTH_4,
 			EXT_CSD_BUS_WIDTH_1,
@@ -1061,13 +1069,15 @@ static int mmc_startup(struct mmc *mmc)
 
 		/* An array to map CSD bus widths to host cap bits */
 		static unsigned ext_to_hostcaps[] = {
+			[EXT_CSD_DDR_BUS_WIDTH_4] = MMC_MODE_DDR_52MHz,
+			[EXT_CSD_DDR_BUS_WIDTH_8] = MMC_MODE_DDR_52MHz,
 			[EXT_CSD_BUS_WIDTH_4] = MMC_MODE_4BIT,
 			[EXT_CSD_BUS_WIDTH_8] = MMC_MODE_8BIT,
 		};
 
 		/* An array to map chosen bus width to an integer */
 		static unsigned widths[] = {
-			8, 4, 1,
+			8, 4, 8, 4, 1,
 		};
 
 		for (idx=0; idx < ARRAY_SIZE(ext_csd_bits); idx++) {

include/mmc.h

@@ -38,6 +38,7 @@
 #define MMC_MODE_8BIT		(1 << 3)
 #define MMC_MODE_SPI		(1 << 4)
 #define MMC_MODE_HC		(1 << 5)
+#define MMC_MODE_DDR_52MHz	(1 << 6)
 
 #define SD_DATA_4BIT	0x00040000
 
@@ -169,10 +170,16 @@
 
 #define EXT_CSD_CARD_TYPE_26	(1 << 0)	/* Card can run at 26MHz */
 #define EXT_CSD_CARD_TYPE_52	(1 << 1)	/* Card can run at 52MHz */
+#define EXT_CSD_CARD_TYPE_DDR_1_8V	(1 << 2)
+#define EXT_CSD_CARD_TYPE_DDR_1_2V	(1 << 3)
+#define EXT_CSD_CARD_TYPE_DDR_52	(EXT_CSD_CARD_TYPE_DDR_1_8V \
+					| EXT_CSD_CARD_TYPE_DDR_1_2V)
 
 #define EXT_CSD_BUS_WIDTH_1	0	/* Card is in 1 bit mode */
 #define EXT_CSD_BUS_WIDTH_4	1	/* Card is in 4 bit mode */
 #define EXT_CSD_BUS_WIDTH_8	2	/* Card is in 8 bit mode */
+#define EXT_CSD_DDR_BUS_WIDTH_4	5	/* Card is in 4 bit DDR mode */
+#define EXT_CSD_DDR_BUS_WIDTH_8	6	/* Card is in 8 bit DDR mode */
 
 #define EXT_CSD_BOOT_ACK_ENABLE			(1 << 6)
 #define EXT_CSD_BOOT_PARTITION_ENABLE		(1 << 3)