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Diffstat (limited to 'doc/README.arm-relocation')
| -rw-r--r-- | doc/README.arm-relocation | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/doc/README.arm-relocation b/doc/README.arm-relocation index 6be1a1292..e3ed60ecd 100644 --- a/doc/README.arm-relocation +++ b/doc/README.arm-relocation @@ -43,6 +43,29 @@ CONFIG_SYS_ARM_WITHOUT_RELOC defined!!! ------------------------------------------------------------------------------------- +For boards which boot from nand_spl, it is possible to save a copy +if TEXT_BASE == relocation address! This prevents that uboot code +is copied again in relocate_code(). + +example for the tx25 board: + +a) cpu starts +b) it copies the first page in nand to internal ram + (nand_spl_code) +c) end executes this code +d) this initialize CPU, RAM, ... and copy itself to RAM + (this bin must fit in one page, so board_init_f() + don;t fit in it ... ) +e) there it copy u-boot to CONFIG_SYS_NAND_U_BOOT_DST and + starts this image @ CONFIG_SYS_NAND_U_BOOT_START +f) u-boot code steps through board_init_f() and calculates + the relocation address and copy itself to it + +If TEXT_BASE == relocation address, the copying of u-boot +in f) could be saved. + +------------------------------------------------------------------------------------- + ToDo: - fill in bd_t infos (check) |