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Diffstat (limited to 'tools/binman/binman.rst')
| -rw-r--r-- | tools/binman/binman.rst | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/tools/binman/binman.rst b/tools/binman/binman.rst index 614df541c5..35de93bd89 100644 --- a/tools/binman/binman.rst +++ b/tools/binman/binman.rst @@ -818,6 +818,42 @@ the 'warning' line in scripts/Makefile.lib to see what it has found:: # u_boot_dtsi_options_debug = $(u_boot_dtsi_options_raw) +Updating an ELF file +==================== + +For the EFI app, where U-Boot is loaded from UEFI and runs as an app, there is +no way to update the devicetree after U-Boot is built. Normally this works by +creating a new u-boot.dtb.out with he updated devicetree, which is automatically +built into the output image. With ELF this is not possible since the ELF is +not part of an image, just a stand-along file. We must create an updated ELF +file with the new devicetree. + +This is handled by the --update-fdt-in-elf option. It takes four arguments, +separated by comma: + + infile - filename of input ELF file, e.g. 'u-boot's + outfile - filename of output ELF file, e.g. 'u-boot.out' + begin_sym - symbol at the start of the embedded devicetree, e.g. + '__dtb_dt_begin' + end_sym - symbol at the start of the embedded devicetree, e.g. + '__dtb_dt_end' + +When this flag is used, U-Boot does all the normal packaging, but as an +additional step, it creates a new ELF file with the new devicetree embedded in +it. + +If logging is enabled you will see a message like this:: + + Updating file 'u-boot' with data length 0x400a (16394) between symbols + '__dtb_dt_begin' and '__dtb_dt_end' + +There must be enough space for the updated devicetree. If not, an error like +the following is produced:: + + ValueError: Not enough space in 'u-boot' for data length 0x400a (16394); + size is 0x1744 (5956) + + Entry Documentation =================== |