1# 2# Device Tree Control 3# 4 5config SUPPORT_OF_CONTROL 6 bool 7 8menu "Device Tree Control" 9 depends on SUPPORT_OF_CONTROL 10 11config OF_CONTROL 12 bool "Run-time configuration via Device Tree" 13 help 14 This feature provides for run-time configuration of U-Boot 15 via a flattened device tree. 16 17config OF_BOARD_FIXUP 18 bool "Board-specific manipulation of Device Tree" 19 help 20 In certain circumstances it is necessary to be able to modify 21 U-Boot's device tree (e.g. to delete device from it). This option 22 make the Device Tree writeable and provides a board-specific 23 "board_fix_fdt" callback (called during pre-relocation time), which 24 enables the board initialization to modifiy the Device Tree. The 25 modified copy is subsequently used by U-Boot after relocation. 26 27config SPL_OF_CONTROL 28 bool "Enable run-time configuration via Device Tree in SPL" 29 depends on SPL && OF_CONTROL 30 help 31 Some boards use device tree in U-Boot but only have 4KB of SRAM 32 which is not enough to support device tree. Enable this option to 33 allow such boards to be supported by U-Boot SPL. 34 35config OF_LIVE 36 bool "Enable use of a live tree" 37 depends on OF_CONTROL 38 help 39 Normally U-Boot uses a flat device tree which saves space and 40 avoids the need to unpack the tree before use. However a flat 41 tree does not support modifcation from within U-Boot since it 42 can invalidate driver-model device tree offsets. This option 43 enables a live tree which is available after relocation, 44 and can be adjusted as needed. 45 46choice 47 prompt "Provider of DTB for DT control" 48 depends on OF_CONTROL 49 50config OF_SEPARATE 51 bool "Separate DTB for DT control" 52 depends on !SANDBOX 53 help 54 If this option is enabled, the device tree will be built and 55 placed as a separate u-boot.dtb file alongside the U-Boot image. 56 57config OF_EMBED 58 bool "Embedded DTB for DT control" 59 help 60 If this option is enabled, the device tree will be picked up and 61 built into the U-Boot image. This is suitable for local debugging 62 and development only and is not recommended for production devices. 63 Boards in the mainline U-Boot tree should not use it. 64 65config OF_BOARD 66 bool "Provided by the board at runtime" 67 depends on !SANDBOX 68 help 69 If this option is enabled, the device tree will be provided by 70 the board at runtime if the board supports it, instead of being 71 bundled with the image. 72 73config OF_HOSTFILE 74 bool "Host filed DTB for DT control" 75 depends on SANDBOX 76 help 77 If this option is enabled, DTB will be read from a file on startup. 78 This is only useful for Sandbox. Use the -d flag to U-Boot to 79 specify the file to read. 80 81endchoice 82 83config DEFAULT_DEVICE_TREE 84 string "Default Device Tree for DT control" 85 depends on OF_CONTROL 86 help 87 This option specifies the default Device Tree used for DT control. 88 It can be overridden from the command line: 89 $ make DEVICE_TREE=<device-tree-name> 90 91config OF_LIST 92 string "List of device tree files to include for DT control" 93 depends on SPL_LOAD_FIT || FIT_EMBED 94 default DEFAULT_DEVICE_TREE 95 help 96 This option specifies a list of device tree files to use for DT 97 control. These will be packaged into a FIT. At run-time, U-boot 98 or SPL will select the correct DT to use by examining the 99 hardware (e.g. reading a board ID value). This is a list of 100 device tree files (without the directory or .dtb suffix) 101 separated by <space>. 102 103config OF_SPL_REMOVE_PROPS 104 string "List of device tree properties to drop for SPL" 105 depends on SPL_OF_CONTROL 106 default "interrupt-parent" if SPL_PINCTRL && SPL_CLK 107 default "clocks clock-names interrupt-parent" if SPL_PINCTRL 108 default "pinctrl-0 pinctrl-names interrupt-parent" if SPL_CLK 109 default "pinctrl-0 pinctrl-names clocks clock-names interrupt-parent" 110 help 111 Since SPL normally runs in a reduced memory space, the device tree 112 is cut down to only what is needed to load and start U-Boot. Only 113 nodes marked with the property "u-boot,dm-pre-reloc" will be 114 included. In addition, some properties are not used by U-Boot and 115 can be discarded. This option defines the list of properties to 116 discard. 117 118config SPL_OF_PLATDATA 119 bool "Generate platform data for use in SPL" 120 depends on SPL_OF_CONTROL 121 help 122 For very constrained SPL environments the overhead of decoding 123 device tree nodes and converting their contents into platform data 124 is too large. This overhead includes libfdt code as well as the 125 device tree contents itself. The latter is fairly compact, but the 126 former can add 3KB or more to a Thumb 2 Image. 127 128 This option enables generation of platform data from the device 129 tree as C code. This code creates devices using U_BOOT_DEVICE() 130 declarations. The benefit is that it allows driver code to access 131 the platform data directly in C structures, avoidin the libfdt 132 overhead. 133 134 This option works by generating C structure declarations for each 135 compatible string, then adding platform data and U_BOOT_DEVICE 136 declarations for each node. See README.platdata for more 137 information. 138 139endmenu 140