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 || MULTI_DTB_FIT 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>. 114 115 116config DTB_RESELECT 117 bool "Support swapping dtbs at a later point in boot" 118 depends on MULTI_DTB_FIT 119 help 120 It is possible during initial boot you may need to use a generic 121 dtb until you can fully determine the board your running on. This 122 config allows boards to implement a function at a later point 123 during boot to switch to the "correct" dtb. 124 125config MULTI_DTB_FIT 126 bool "Support embedding several DTBs in a FIT image for u-boot" 127 help 128 This option provides hooks to allow U-boot to parse an 129 appended FIT image and enable board specific code to then select 130 the correct DTB to be used. Use this if you need to support 131 multiple DTBs but don't use the SPL. 132 133config OF_SPL_REMOVE_PROPS 134 string "List of device tree properties to drop for SPL" 135 depends on SPL_OF_CONTROL 136 default "interrupt-parent" if SPL_PINCTRL && SPL_CLK 137 default "clocks clock-names interrupt-parent" if SPL_PINCTRL 138 default "pinctrl-0 pinctrl-names interrupt-parent" if SPL_CLK 139 default "pinctrl-0 pinctrl-names clocks clock-names interrupt-parent" 140 help 141 Since SPL normally runs in a reduced memory space, the device tree 142 is cut down to only what is needed to load and start U-Boot. Only 143 nodes marked with the property "u-boot,dm-pre-reloc" will be 144 included. In addition, some properties are not used by U-Boot and 145 can be discarded. This option defines the list of properties to 146 discard. 147 148config SPL_OF_PLATDATA 149 bool "Generate platform data for use in SPL" 150 depends on SPL_OF_CONTROL 151 help 152 For very constrained SPL environments the overhead of decoding 153 device tree nodes and converting their contents into platform data 154 is too large. This overhead includes libfdt code as well as the 155 device tree contents itself. The latter is fairly compact, but the 156 former can add 3KB or more to a Thumb 2 Image. 157 158 This option enables generation of platform data from the device 159 tree as C code. This code creates devices using U_BOOT_DEVICE() 160 declarations. The benefit is that it allows driver code to access 161 the platform data directly in C structures, avoidin the libfdt 162 overhead. 163 164 This option works by generating C structure declarations for each 165 compatible string, then adding platform data and U_BOOT_DEVICE 166 declarations for each node. See README.platdata for more 167 information. 168 169config TPL_OF_PLATDATA 170 bool "Generate platform data for use in TPL" 171 depends on TPL_OF_CONTROL 172 help 173 For very constrained SPL environments the overhead of decoding 174 device tree nodes and converting their contents into platform data 175 is too large. This overhead includes libfdt code as well as the 176 device tree contents itself. The latter is fairly compact, but the 177 former can add 3KB or more to a Thumb 2 Image. 178 179 This option enables generation of platform data from the device 180 tree as C code. This code creates devices using U_BOOT_DEVICE() 181 declarations. The benefit is that it allows driver code to access 182 the platform data directly in C structures, avoidin the libfdt 183 overhead. 184 185 This option works by generating C structure declarations for each 186 compatible string, then adding platform data and U_BOOT_DEVICE 187 declarations for each node. See README.platdata for more 188 information. 189 190endmenu 191 192config MKIMAGE_DTC_PATH 193 string "Path to dtc binary for use within mkimage" 194 default "dtc" 195 help 196 The mkimage host tool will, in order to generate FIT images make 197 calls to the dtc application in order to create the output. In 198 some cases the system dtc may not support all required features 199 and the path to a different version should be given here. 200