config BLK bool "Support block devices" depends on DM help Enable support for block devices, such as SCSI, MMC and USB flash sticks. These provide a block-level interface which permits reading, writing and (in some cases) erasing blocks. Block devices often have a partition table which allows the device to be partitioned into several areas, called 'partitions' in U-Boot. A filesystem can be placed in each partition.
config DISK bool "Support disk controllers with driver model" depends on DM default y if DM help This enables a uclass for disk controllers in U-Boot. Various driver types can use this, such as AHCI/SATA. It does not provide any standard operations at present. The block device interface has not been converted to driver model.
config BLOCK_CACHE bool "Use block device cache" default n help This option enables a disk-block cache for all block devices. This is most useful when accessing filesystems under U-Boot since it will prevent repeated reads from directory structures and other filesystem data structures.