+#define SD_CMD_APP_SEND_SCR 51
+
+/* SCR definitions in different words */
+#define SD_HIGHSPEED_BUSY 0x00020000
+#define SD_HIGHSPEED_SUPPORTED 0x00020000
+
+#define MMC_HS_TIMING 0x00000100
+#define MMC_HS_52MHZ 0x2
+
+#define OCR_BUSY 0x80000000
+#define OCR_HCS 0x40000000
+
+#define MMC_VDD_165_195 0x00000080 /* VDD voltage 1.65 - 1.95 */
+#define MMC_VDD_20_21 0x00000100 /* VDD voltage 2.0 ~ 2.1 */
+#define MMC_VDD_21_22 0x00000200 /* VDD voltage 2.1 ~ 2.2 */
+#define MMC_VDD_22_23 0x00000400 /* VDD voltage 2.2 ~ 2.3 */
+#define MMC_VDD_23_24 0x00000800 /* VDD voltage 2.3 ~ 2.4 */
+#define MMC_VDD_24_25 0x00001000 /* VDD voltage 2.4 ~ 2.5 */
+#define MMC_VDD_25_26 0x00002000 /* VDD voltage 2.5 ~ 2.6 */
+#define MMC_VDD_26_27 0x00004000 /* VDD voltage 2.6 ~ 2.7 */
+#define MMC_VDD_27_28 0x00008000 /* VDD voltage 2.7 ~ 2.8 */
+#define MMC_VDD_28_29 0x00010000 /* VDD voltage 2.8 ~ 2.9 */
+#define MMC_VDD_29_30 0x00020000 /* VDD voltage 2.9 ~ 3.0 */
+#define MMC_VDD_30_31 0x00040000 /* VDD voltage 3.0 ~ 3.1 */
+#define MMC_VDD_31_32 0x00080000 /* VDD voltage 3.1 ~ 3.2 */
+#define MMC_VDD_32_33 0x00100000 /* VDD voltage 3.2 ~ 3.3 */
+#define MMC_VDD_33_34 0x00200000 /* VDD voltage 3.3 ~ 3.4 */
+#define MMC_VDD_34_35 0x00400000 /* VDD voltage 3.4 ~ 3.5 */
+#define MMC_VDD_35_36 0x00800000 /* VDD voltage 3.5 ~ 3.6 */
+
+#define MMC_SWITCH_MODE_CMD_SET 0x00 /* Change the command set */
+#define MMC_SWITCH_MODE_SET_BITS 0x01 /* Set bits in EXT_CSD byte
+ addressed by index which are
+ 1 in value field */
+#define MMC_SWITCH_MODE_CLEAR_BITS 0x02 /* Clear bits in EXT_CSD byte
+ addressed by index, which are
+ 1 in value field */
+#define MMC_SWITCH_MODE_WRITE_BYTE 0x03 /* Set target byte to value */
+
+#define SD_SWITCH_CHECK 0
+#define SD_SWITCH_SWITCH 1
+
+/*
+ * EXT_CSD fields
+ */
+
+#define EXT_CSD_BUS_WIDTH 183 /* R/W */
+#define EXT_CSD_HS_TIMING 185 /* R/W */
+#define EXT_CSD_CARD_TYPE 196 /* RO */
+#define EXT_CSD_REV 192 /* RO */
+#define EXT_CSD_SEC_CNT 212 /* RO, 4 bytes */
+
+/*
+ * EXT_CSD field definitions
+ */
+
+#define EXT_CSD_CMD_SET_NORMAL (1<<0)
+#define EXT_CSD_CMD_SET_SECURE (1<<1)
+#define EXT_CSD_CMD_SET_CPSECURE (1<<2)
+
+#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_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 */