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#
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# Device Tree Control
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#
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config SUPPORT_OF_CONTROL
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bool
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menu "Device Tree Control"
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depends on SUPPORT_OF_CONTROL
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config OF_CONTROL
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bool "Run-time configuration via Device Tree"
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help
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This feature provides for run-time configuration of U-Boot
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via a flattened device tree.
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dm: Add callback to modify the device tree
Certain boards come in different variations by way of utilizing daughter
boards, for example. These boards might contain additional chips, which
are added to the main board's busses, e.g. I2C.
The device tree support for such boards would either, quite naturally,
employ the overlay mechanism to add such chips to the tree, or would use
one large default device tree, and delete the devices that are actually
not present.
Regardless of approach, even on the U-Boot level, a modification of the
device tree is a prerequisite to have such modular families of boards
supported properly.
Therefore, we add an option to make the U-Boot device tree (the actual
copy later used by the driver model) writeable, and add a callback
method that allows boards to modify the device tree at an early stage,
at which, hopefully, also the application of device tree overlays will
be possible.
Signed-off-by: Mario Six <mario.six@gdsys.cc>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Stefan Roese <sr@denx.de>
7 years ago
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config OF_BOARD_FIXUP
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bool "Board-specific manipulation of Device Tree"
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help
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In certain circumstances it is necessary to be able to modify
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U-Boot's device tree (e.g. to delete device from it). This option
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make the Device Tree writeable and provides a board-specific
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"board_fix_fdt" callback (called during pre-relocation time), which
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enables the board initialization to modifiy the Device Tree. The
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modified copy is subsequently used by U-Boot after relocation.
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config SPL_OF_CONTROL
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bool "Enable run-time configuration via Device Tree in SPL"
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depends on SPL && OF_CONTROL
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help
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Some boards use device tree in U-Boot but only have 4KB of SRAM
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which is not enough to support device tree. Enable this option to
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allow such boards to be supported by U-Boot SPL.
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config TPL_OF_CONTROL
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bool "Enable run-time configuration via Device Tree in TPL"
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depends on TPL && OF_CONTROL
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help
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Some boards use device tree in U-Boot but only have 4KB of SRAM
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which is not enough to support device tree. Enable this option to
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allow such boards to be supported by U-Boot TPL.
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config OF_LIVE
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bool "Enable use of a live tree"
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depends on OF_CONTROL
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help
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Normally U-Boot uses a flat device tree which saves space and
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avoids the need to unpack the tree before use. However a flat
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tree does not support modifcation from within U-Boot since it
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can invalidate driver-model device tree offsets. This option
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enables a live tree which is available after relocation,
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and can be adjusted as needed.
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choice
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prompt "Provider of DTB for DT control"
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depends on OF_CONTROL
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config OF_SEPARATE
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bool "Separate DTB for DT control"
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depends on !SANDBOX
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help
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If this option is enabled, the device tree will be built and
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placed as a separate u-boot.dtb file alongside the U-Boot image.
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config OF_EMBED
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bool "Embedded DTB for DT control"
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help
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If this option is enabled, the device tree will be picked up and
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built into the U-Boot image. This is suitable for local debugging
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and development only and is not recommended for production devices.
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Boards in the mainline U-Boot tree should not use it.
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config OF_BOARD
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bool "Provided by the board at runtime"
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depends on !SANDBOX
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help
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If this option is enabled, the device tree will be provided by
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the board at runtime if the board supports it, instead of being
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bundled with the image.
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config OF_HOSTFILE
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bool "Host filed DTB for DT control"
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depends on SANDBOX
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help
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If this option is enabled, DTB will be read from a file on startup.
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This is only useful for Sandbox. Use the -d flag to U-Boot to
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specify the file to read.
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endchoice
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config DEFAULT_DEVICE_TREE
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string "Default Device Tree for DT control"
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depends on OF_CONTROL
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help
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This option specifies the default Device Tree used for DT control.
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It can be overridden from the command line:
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$ make DEVICE_TREE=<device-tree-name>
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config OF_LIST
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string "List of device tree files to include for DT control"
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depends on SPL_LOAD_FIT || FIT_EMBED
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default DEFAULT_DEVICE_TREE
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help
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This option specifies a list of device tree files to use for DT
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control. These will be packaged into a FIT. At run-time, U-boot
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or SPL will select the correct DT to use by examining the
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hardware (e.g. reading a board ID value). This is a list of
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device tree files (without the directory or .dtb suffix)
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separated by <space>.
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config OF_SPL_REMOVE_PROPS
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string "List of device tree properties to drop for SPL"
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depends on SPL_OF_CONTROL
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default "interrupt-parent" if SPL_PINCTRL && SPL_CLK
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default "clocks clock-names interrupt-parent" if SPL_PINCTRL
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default "pinctrl-0 pinctrl-names interrupt-parent" if SPL_CLK
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default "pinctrl-0 pinctrl-names clocks clock-names interrupt-parent"
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help
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Since SPL normally runs in a reduced memory space, the device tree
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is cut down to only what is needed to load and start U-Boot. Only
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nodes marked with the property "u-boot,dm-pre-reloc" will be
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included. In addition, some properties are not used by U-Boot and
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can be discarded. This option defines the list of properties to
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discard.
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config SPL_OF_PLATDATA
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bool "Generate platform data for use in SPL"
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depends on SPL_OF_CONTROL
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help
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For very constrained SPL environments the overhead of decoding
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device tree nodes and converting their contents into platform data
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is too large. This overhead includes libfdt code as well as the
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device tree contents itself. The latter is fairly compact, but the
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former can add 3KB or more to a Thumb 2 Image.
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This option enables generation of platform data from the device
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tree as C code. This code creates devices using U_BOOT_DEVICE()
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declarations. The benefit is that it allows driver code to access
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the platform data directly in C structures, avoidin the libfdt
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overhead.
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This option works by generating C structure declarations for each
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compatible string, then adding platform data and U_BOOT_DEVICE
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declarations for each node. See README.platdata for more
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information.
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config TPL_OF_PLATDATA
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bool "Generate platform data for use in TPL"
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depends on TPL_OF_CONTROL
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help
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For very constrained SPL environments the overhead of decoding
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device tree nodes and converting their contents into platform data
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is too large. This overhead includes libfdt code as well as the
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device tree contents itself. The latter is fairly compact, but the
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former can add 3KB or more to a Thumb 2 Image.
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This option enables generation of platform data from the device
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tree as C code. This code creates devices using U_BOOT_DEVICE()
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declarations. The benefit is that it allows driver code to access
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the platform data directly in C structures, avoidin the libfdt
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overhead.
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This option works by generating C structure declarations for each
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compatible string, then adding platform data and U_BOOT_DEVICE
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declarations for each node. See README.platdata for more
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information.
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endmenu
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