# # Device Tree Control # config SUPPORT_OF_CONTROL bool menu "Device Tree Control" depends on SUPPORT_OF_CONTROL config OF_CONTROL bool "Run-time configuration via Device Tree" help This feature provides for run-time configuration of U-Boot via a flattened device tree. config OF_BOARD_FIXUP bool "Board-specific manipulation of Device Tree" help In certain circumstances it is necessary to be able to modify U-Boot's device tree (e.g. to delete device from it). This option make the Device Tree writeable and provides a board-specific "board_fix_fdt" callback (called during pre-relocation time), which enables the board initialization to modifiy the Device Tree. The modified copy is subsequently used by U-Boot after relocation. config SPL_OF_CONTROL bool "Enable run-time configuration via Device Tree in SPL" depends on SPL && OF_CONTROL help Some boards use device tree in U-Boot but only have 4KB of SRAM which is not enough to support device tree. Enable this option to allow such boards to be supported by U-Boot SPL. config OF_LIVE bool "Enable use of a live tree" depends on OF_CONTROL help Normally U-Boot uses a flat device tree which saves space and avoids the need to unpack the tree before use. However a flat tree does not support modifcation from within U-Boot since it can invalidate driver-model device tree offsets. This option enables a live tree which is available after relocation, and can be adjusted as needed. choice prompt "Provider of DTB for DT control" depends on OF_CONTROL config OF_SEPARATE bool "Separate DTB for DT control" depends on !SANDBOX help If this option is enabled, the device tree will be built and placed as a separate u-boot.dtb file alongside the U-Boot image. config OF_EMBED bool "Embedded DTB for DT control" help If this option is enabled, the device tree will be picked up and built into the U-Boot image. This is suitable for local debugging and development only and is not recommended for production devices. Boards in the mainline U-Boot tree should not use it. config OF_BOARD bool "Provided by the board at runtime" depends on !SANDBOX help If this option is enabled, the device tree will be provided by the board at runtime if the board supports it, instead of being bundled with the image. config OF_HOSTFILE bool "Host filed DTB for DT control" depends on SANDBOX help If this option is enabled, DTB will be read from a file on startup. This is only useful for Sandbox. Use the -d flag to U-Boot to specify the file to read. endchoice config DEFAULT_DEVICE_TREE string "Default Device Tree for DT control" depends on OF_CONTROL help This option specifies the default Device Tree used for DT control. It can be overridden from the command line: $ make DEVICE_TREE=<device-tree-name> config OF_LIST string "List of device tree files to include for DT control" depends on SPL_LOAD_FIT || FIT_EMBED default DEFAULT_DEVICE_TREE help This option specifies a list of device tree files to use for DT control. These will be packaged into a FIT. At run-time, U-boot or SPL will select the correct DT to use by examining the hardware (e.g. reading a board ID value). This is a list of device tree files (without the directory or .dtb suffix) separated by <space>. config OF_SPL_REMOVE_PROPS string "List of device tree properties to drop for SPL" depends on SPL_OF_CONTROL default "interrupt-parent" if SPL_PINCTRL && SPL_CLK default "clocks clock-names interrupt-parent" if SPL_PINCTRL default "pinctrl-0 pinctrl-names interrupt-parent" if SPL_CLK default "pinctrl-0 pinctrl-names clocks clock-names interrupt-parent" help Since SPL normally runs in a reduced memory space, the device tree is cut down to only what is needed to load and start U-Boot. Only nodes marked with the property "u-boot,dm-pre-reloc" will be included. In addition, some properties are not used by U-Boot and can be discarded. This option defines the list of properties to discard. config SPL_OF_PLATDATA bool "Generate platform data for use in SPL" depends on SPL_OF_CONTROL help For very constrained SPL environments the overhead of decoding device tree nodes and converting their contents into platform data is too large. This overhead includes libfdt code as well as the device tree contents itself. The latter is fairly compact, but the former can add 3KB or more to a Thumb 2 Image. This option enables generation of platform data from the device tree as C code. This code creates devices using U_BOOT_DEVICE() declarations. The benefit is that it allows driver code to access the platform data directly in C structures, avoidin the libfdt overhead. This option works by generating C structure declarations for each compatible string, then adding platform data and U_BOOT_DEVICE declarations for each node. See README.platdata for more information. endmenu