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#
# 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
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, 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
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