mmc: read the size of eMMC enhanced user data area

This modification reads the size of the eMMC enhanced user data area
upon initialization of an mmc device, it will be used later by
mmcinfo.

Signed-off-by: Diego Santa Cruz <Diego.SantaCruz@spinetix.com>

drivers/mmc/mmc.c

@@ -1031,6 +1031,21 @@ static int mmc_startup(struct mmc *mmc)
 				has_parts = true;
 		}
 
+		mmc->enh_user_size =
+			(ext_csd[EXT_CSD_ENH_SIZE_MULT+2] << 16) +
+			(ext_csd[EXT_CSD_ENH_SIZE_MULT+1] << 8) +
+			ext_csd[EXT_CSD_ENH_SIZE_MULT];
+		mmc->enh_user_size *= ext_csd[EXT_CSD_HC_ERASE_GRP_SIZE];
+		mmc->enh_user_size *= ext_csd[EXT_CSD_HC_WP_GRP_SIZE];
+		mmc->enh_user_size <<= 19;
+		mmc->enh_user_start =
+			(ext_csd[EXT_CSD_ENH_START_ADDR+3] << 24) +
+			(ext_csd[EXT_CSD_ENH_START_ADDR+2] << 16) +
+			(ext_csd[EXT_CSD_ENH_START_ADDR+1] << 8) +
+			ext_csd[EXT_CSD_ENH_START_ADDR];
+		if (mmc->high_capacity)
+			mmc->enh_user_start <<= 9;
+
 		/*
 		 * Host needs to enable ERASE_GRP_DEF bit if device is
 		 * partitioned. This bit will be lost every time after a reset

include/mmc.h

@@ -147,6 +147,8 @@
 /*
  * EXT_CSD fields
  */
+#define EXT_CSD_ENH_START_ADDR		136	/* R/W */
+#define EXT_CSD_ENH_SIZE_MULT		140	/* R/W */
 #define EXT_CSD_GP_SIZE_MULT		143	/* R/W */
 #define EXT_CSD_PARTITION_SETTING	155	/* R/W */
 #define EXT_CSD_PARTITIONS_ATTRIBUTE	156	/* R/W */
@@ -319,6 +321,8 @@ struct mmc {
 	u64 capacity_boot;
 	u64 capacity_rpmb;
 	u64 capacity_gp[4];
+	u64 enh_user_start;
+	u64 enh_user_size;
 	block_dev_desc_t block_dev;
 	char op_cond_pending;	/* 1 if we are waiting on an op_cond command */
 	char init_in_progress;	/* 1 if we have done mmc_start_init() */