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Add a Kconfig option to enable a live device tree, built at run time from the flat tree. Also add structure definitions and a root node. Signed-off-by: Simon Glass <sjg@chromium.org>
139 lines
4.9 KiB
Plaintext
139 lines
4.9 KiB
Plaintext
#
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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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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 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
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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, SPL will
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select the correct DT to use by examining the hardware (e.g.
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reading a board ID value). This is a list of device tree files
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(without the directory or .dtb suffix) 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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endmenu
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