1# 2# Device Tree Control 3# 4 5config SUPPORT_OF_CONTROL 6 bool 7 8config DTC 9 bool 10 11menu "Device Tree Control" 12 depends on SUPPORT_OF_CONTROL 13 14config OF_CONTROL 15 bool "Run-time configuration via Device Tree" 16 select DTC 17 help 18 This feature provides for run-time configuration of U-Boot 19 via a flattened device tree. 20 21config OF_BOARD_FIXUP 22 bool "Board-specific manipulation of Device Tree" 23 help 24 In certain circumstances it is necessary to be able to modify 25 U-Boot's device tree (e.g. to delete device from it). This option 26 make the Device Tree writeable and provides a board-specific 27 "board_fix_fdt" callback (called during pre-relocation time), which 28 enables the board initialization to modifiy the Device Tree. The 29 modified copy is subsequently used by U-Boot after relocation. 30 31config SPL_OF_CONTROL 32 bool "Enable run-time configuration via Device Tree in SPL" 33 depends on SPL && OF_CONTROL 34 help 35 Some boards use device tree in U-Boot but only have 4KB of SRAM 36 which is not enough to support device tree. Enable this option to 37 allow such boards to be supported by U-Boot SPL. 38 39config TPL_OF_CONTROL 40 bool "Enable run-time configuration via Device Tree in TPL" 41 depends on TPL && OF_CONTROL 42 help 43 Some boards use device tree in U-Boot but only have 4KB of SRAM 44 which is not enough to support device tree. Enable this option to 45 allow such boards to be supported by U-Boot TPL. 46 47config OF_LIVE 48 bool "Enable use of a live tree" 49 depends on OF_CONTROL 50 help 51 Normally U-Boot uses a flat device tree which saves space and 52 avoids the need to unpack the tree before use. However a flat 53 tree does not support modifcation from within U-Boot since it 54 can invalidate driver-model device tree offsets. This option 55 enables a live tree which is available after relocation, 56 and can be adjusted as needed. 57 58choice 59 prompt "Provider of DTB for DT control" 60 depends on OF_CONTROL 61 62config OF_SEPARATE 63 bool "Separate DTB for DT control" 64 depends on !SANDBOX 65 help 66 If this option is enabled, the device tree will be built and 67 placed as a separate u-boot.dtb file alongside the U-Boot image. 68 69config OF_EMBED 70 bool "Embedded DTB for DT control" 71 help 72 If this option is enabled, the device tree will be picked up and 73 built into the U-Boot image. This is suitable for local debugging 74 and development only and is not recommended for production devices. 75 Boards in the mainline U-Boot tree should not use it. 76 77config OF_BOARD 78 bool "Provided by the board at runtime" 79 depends on !SANDBOX 80 help 81 If this option is enabled, the device tree will be provided by 82 the board at runtime if the board supports it, instead of being 83 bundled with the image. 84 85config OF_HOSTFILE 86 bool "Host filed DTB for DT control" 87 depends on SANDBOX 88 help 89 If this option is enabled, DTB will be read from a file on startup. 90 This is only useful for Sandbox. Use the -d flag to U-Boot to 91 specify the file to read. 92 93endchoice 94 95config DEFAULT_DEVICE_TREE 96 string "Default Device Tree for DT control" 97 depends on OF_CONTROL 98 help 99 This option specifies the default Device Tree used for DT control. 100 It can be overridden from the command line: 101 $ make DEVICE_TREE=<device-tree-name> 102 103config OF_LIST 104 string "List of device tree files to include for DT control" 105 depends on SPL_LOAD_FIT || FIT_EMBED 106 default DEFAULT_DEVICE_TREE 107 help 108 This option specifies a list of device tree files to use for DT 109 control. These will be packaged into a FIT. At run-time, U-boot 110 or SPL will select the correct DT to use by examining the 111 hardware (e.g. reading a board ID value). This is a list of 112 device tree files (without the directory or .dtb suffix) 113 separated by <space>. 114 115config OF_SPL_REMOVE_PROPS 116 string "List of device tree properties to drop for SPL" 117 depends on SPL_OF_CONTROL 118 default "interrupt-parent" if SPL_PINCTRL && SPL_CLK 119 default "clocks clock-names interrupt-parent" if SPL_PINCTRL 120 default "pinctrl-0 pinctrl-names interrupt-parent" if SPL_CLK 121 default "pinctrl-0 pinctrl-names clocks clock-names interrupt-parent" 122 help 123 Since SPL normally runs in a reduced memory space, the device tree 124 is cut down to only what is needed to load and start U-Boot. Only 125 nodes marked with the property "u-boot,dm-pre-reloc" will be 126 included. In addition, some properties are not used by U-Boot and 127 can be discarded. This option defines the list of properties to 128 discard. 129 130config SPL_OF_PLATDATA 131 bool "Generate platform data for use in SPL" 132 depends on SPL_OF_CONTROL 133 help 134 For very constrained SPL environments the overhead of decoding 135 device tree nodes and converting their contents into platform data 136 is too large. This overhead includes libfdt code as well as the 137 device tree contents itself. The latter is fairly compact, but the 138 former can add 3KB or more to a Thumb 2 Image. 139 140 This option enables generation of platform data from the device 141 tree as C code. This code creates devices using U_BOOT_DEVICE() 142 declarations. The benefit is that it allows driver code to access 143 the platform data directly in C structures, avoidin the libfdt 144 overhead. 145 146 This option works by generating C structure declarations for each 147 compatible string, then adding platform data and U_BOOT_DEVICE 148 declarations for each node. See README.platdata for more 149 information. 150 151config TPL_OF_PLATDATA 152 bool "Generate platform data for use in TPL" 153 depends on TPL_OF_CONTROL 154 help 155 For very constrained SPL environments the overhead of decoding 156 device tree nodes and converting their contents into platform data 157 is too large. This overhead includes libfdt code as well as the 158 device tree contents itself. The latter is fairly compact, but the 159 former can add 3KB or more to a Thumb 2 Image. 160 161 This option enables generation of platform data from the device 162 tree as C code. This code creates devices using U_BOOT_DEVICE() 163 declarations. The benefit is that it allows driver code to access 164 the platform data directly in C structures, avoidin the libfdt 165 overhead. 166 167 This option works by generating C structure declarations for each 168 compatible string, then adding platform data and U_BOOT_DEVICE 169 declarations for each node. See README.platdata for more 170 information. 171 172endmenu 173 174config MKIMAGE_DTC_PATH 175 string "Path to dtc binary for use within mkimage" 176 default "dtc" 177 help 178 The mkimage host tool will, in order to generate FIT images make 179 calls to the dtc application in order to create the output. In 180 some cases the system dtc may not support all required features 181 and the path to a different version should be given here. 182