drivers/block/Kconfig

config BLK
	bool # "Support block devices"
	depends on DM
	default y if MMC || USB || SCSI || NVME || IDE || AHCI || SATA
	default y if EFI_MEDIA || VIRTIO_BLK || PVBLOCK
	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 SPL_LEGACY_BLOCK
	bool # "Enable Legacy Block Device"
	depends on SPL && !DM_SPL
	default y if SPL_MMC || SPL_USB_STORAGE || SCSI || NVME || IDE
	default y if SPL_AHCI_PCI
	help
	  Some devices require block support whether or not DM is enabled. This
	  is only supported in SPL. With this, the blk uclass is not used, but
	  instead a legacy implementation of block devices is used, with all
	  devices consisting of 'struct blk_desc' records.

config SPL_BLK
	bool "Support block devices in SPL"
	depends on SPL_DM && BLK
	default y
	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 TPL_BLK
	bool "Support block devices in TPL"
	depends on TPL_DM && BLK
	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 VPL_BLK
	bool "Support block devices in VPL"
	depends on VPL_DM && BLK
	default y
	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 BLOCK_CACHE
	bool "Use block device cache"
	depends on BLK
	default y
	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.

config BLKMAP
	bool "Composable virtual block devices (blkmap)"
	depends on BLK
	help
 	  Create virtual block devices that are backed by various sources,
 	  e.g. RAM, or parts of an existing block device. Though much more
 	  rudimentary, it borrows a lot of ideas from Linux's device mapper
 	  subsystem.

	  Example use-cases:
	  - Treat a region of RAM as a block device, i.e. a RAM disk. This let's
            you extract files from filesystem images stored in RAM (perhaps as a
            result of a TFTP transfer).
	  - Create a virtual partition on an existing device. This let's you
            access filesystems that aren't stored at an exact partition
            boundary. A common example is a filesystem image embedded in an FIT
            image.

config SPL_BLOCK_CACHE
	bool "Use block device cache in SPL"
	depends on SPL_BLK
	help
	  This option enables the disk-block cache in SPL

config TPL_BLOCK_CACHE
	bool "Use block device cache in TPL"
	depends on TPL_BLK
	help
	  This option enables the disk-block cache in TPL

config EFI_MEDIA
	bool "Support EFI media drivers"
	default y if EFI || SANDBOX
	help
	  Enable this to support media devices on top of UEFI. This enables
	  just the uclass so you also need a specific driver to make this do
	  anything.

	  For sandbox there is a test driver.

if EFI_MEDIA

config EFI_MEDIA_SANDBOX
	bool "Sandbox EFI media driver"
	depends on SANDBOX
	default y
	help
	  Enables a simple sandbox media driver, used for testing just the
	  EFI_MEDIA uclass. It does not do anything useful, since sandbox does
	  not actually support running on top of UEFI.

config EFI_MEDIA_BLK
	bool "EFI media block driver"
	depends on EFI_APP
	default y
	help
	  Enables a block driver for providing access to UEFI devices. This
	  allows use of block devices detected by the underlying UEFI
	  implementation. With this it is possible to use filesystems on these
	  devices, for example.

endif  # EFI_MEDIA

config IDE
	bool "Support IDE controllers"
	help
	  Enables support for IDE (Integrated Drive Electronics) hard drives.
	  This allows access to raw blocks and filesystems on an IDE drive
	  from U-Boot. See also CMD_IDE which provides an 'ide' command for
	  performing various IDE operations.

if IDE

config SYS_IDE_MAXBUS
	hex "Maximumm number of IDE buses"
	default 2
	help
	  This is the number of IDE buses provided by the board. Each one
	  can have one or two devices. One is designated the master and the
	  other one the slave. It is not required to have one or both on any
	  controller.

config SYS_IDE_MAXDEVICE
	hex "Maximum number of IDE devices"
	default 2
	help
	  This is the number of IDE devices which can be connected to the
	  board. Normally this is 2 * CONFIG_SYS_IDE_MAXBUS since up to two
	  devices can be connected to each bus. The number of devices actually
	  connected is determined by probing.

config SYS_ATA_BASE_ADDR
	hex "Base address of IDE controller"
	default 0
	help
	  This is the address of the IDE controller, from which other addresses
	  are calculated. Each bus is at a fixed offset from this address,
	  so it assumed that they are in the same area of the I/O space or
	  memory.

config SYS_ATA_STRIDE
	hex "IDE port stride"
	default 0x1
	help
	  This is the distance between each IDE register, in bytes. For an
	  8-bit controller this is typically 1, meaning that the registers
	  appear at consecutive bytes. If the value 2 two, that might indicate
	  a 16-bit register space.

config SYS_ATA_DATA_OFFSET
	hex "Offset of the data register"
	default 0x0
	help
	  This is the offset of the controller's data register from the base
	  address of the controller. This is typically 0, but may be something
	  else if there are some other registers at the start of the
	  controller space.

config SYS_ATA_REG_OFFSET
	hex "Offset of the register space"
	default 0x0
	help
	  This is the offset of the controller's 'register' space from the base
	  address of the controller. The data register (which is typically at
	  offset 0) has its own CONFIG, to deal with controllers where it is
	  somewhere else. Register 1 will be at this offset + 1, register 2 at
	  CONFIG_SYS_ATA_REG_OFFSET + 2, etc.

config SYS_ATA_ALT_OFFSET
	hex "Offset of the alternative registers"
	default 0x0
	help
	  This is the offset of the controller's 'alternative' space from the
	  base address of the controller. This allows these registers to be
	  located separately from the data and register space.

config SYS_ATA_IDE0_OFFSET
	hex "Offset of bus 0"
	default 0x1f0
	help
	  This is the start offset of bus 0 from the start of the
	  controller registers. All the other registers are calculated from
	  this address. using the above options. For x86 hardware this is often
	  0x1f0.

config SYS_ATA_IDE1_OFFSET
	hex "Offset of bus 1"
	default 0x170
	help
	  This is the start offset of bus 1 from the start of the
	  controller registers. All the other registers are calculated from
	  this address. using the above options. For x86 hardware this is often
	  0x170.

config ATAPI
	bool "Enable ATAPI support"
	help
	  This enabled Advanced Technology Attachment Packet Interface (ATAPI),
	  a protocol that allows a greater variety of devices to be connected
	  to the IDE port than with plain ATA. It allows SCSI commands to be
	  sent across the bus, e.g. to support optical drives.

config IDE_RESET
	bool "Support board-specific reset"
	help
	  If this is defined, IDE Reset will be performed by calling the
	  function:

	     ide_set_reset(int reset)

	  where reset is 1 to assert reset and 0 to de-assert it. This function
	  must be defined in a board-specific file.

endif  # IDE

config LBA48
	bool "Enable LBA support for disks larger than 137GB"
	help
	  Set this to enable support for disks larger than 137GB.
	  Also look at CONFIG_SYS_64BIT_LBA.  Without both of these, LBA48
	  support uses 32bit variables and will 'only' support disks up to
	  2.1TB.

config SYS_64BIT_LBA
	bool "Enable 64bit number of blocks on a block device"
	help
	  Make the block subsystem use 64bit sector addresses, rather than the
	  default of 32bit.