# define CONFIG_OF_LIBFDT               /* Device Tree support */

重新编译u-boot，就可以实现对device tree的支持。

2. u-boot下的fdt命令使用

2.1 首先查看fdt的帮助信息。

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U-Boot> fdt
fdt - flattened device tree utility commands

Usage:
fdt addr <addr> [<length>] - Set the fdt location to <addr>
fdt move <fdt> <newaddr> <length> - Copy the fdt to <addr> and make it active
fdt resize - Resize fdt to size + padding to 4k addr
fdt print <path> [<prop>] - Recursive print starting at <path>
fdt list <path> [<prop>] - Print one level starting at <path>
fdt set <path> <prop> [<val>] - Set <property> [to <val>]
fdt mknode <path> <node> - Create a new node after <path>
fdt rm <path> [<prop>] - Delete the node or <property>
fdt header - Display header info
fdt bootcpu <id> - Set boot cpuid
fdt memory <addr> <size> - Add/Update memory node
fdt rsvmem print - Show current mem reserves
fdt rsvmem add <addr> <size> - Add a mem reserve
fdt rsvmem delete <index> - Delete a mem reserves
fdt chosen [<start> <end>] - Add/update the /chosen branch in the tree
<start>/<end> - initrd start/end addr
NOTE: Dereference aliases by omiting the leading '/', e.g. fdt print ethernet0.
U-Boot>

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