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. config SPL_BLK_FS bool "Load images from filesystems on block devices" depends on SPL_BLK help Use generic support to load images from fat/ext filesystems on different types of block devices such as NVMe. 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 0x0 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.