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AM5728: U-boot compilations and lower level initialization understanding

matt hardy
Prodigy 60 points

Part Number: AM5728

Hi I have a AM5728 Industrial development kit, TMDXIDK5728.

I want to understand the u-boot process and initialization process, for that I have downloaded the u-boot source code and arm toolchain but not understanding the process to begin with. I mean the board configuration files. If somebody have done some work in this then please do share the knowledge. I just want to get started with u-boot compilation and debugging steps first .

I have managed to compile u-boot for kit, copied the u-boot.img on 1st partition on SD card  and connected the SD card to borad, but couldn't see anything comming up on terminal board like no u-boot menu.

I have used "gcc-arm-8.3-2019.03-x86_64-arm-linux-gnueabihf" toolchain  and u-boot from github repository with commit "36bdcf7f3b17ec6d8cec782e7f1d5b0b8014300a".

What mistake am I doing, as per my understanding I should be able to see the u-boot prompt atleast.

  • 0
    TI__Guru**** 169600 points

    Hi Matt,

    Once you download the u-boot source code reposiroty.

    You can go to the u-boot folder and do:

    make distclean
    make am57xx_evm_defconfig
    make

    The above steps should compile you u-boot.img and MLO in the source folder.

    You need to copy them to boot partition of you SD card.

    MLO is basically the SPL and u-boot.img is the u-boot image.

    Thanks,
    Keerthy

  • 0 in reply to Keerthy J
    Prodigy 60 points

    Hi Keerthy,

    Thanks for taking time to suggest the answer. As I mentioned in question that I was able to generate u-boot.img.

    Now when I copy the u-boot.img on SD card and plug it into Devkit, I was expecting some message on terminal like u-boot prompt.

    Also MLO is the secondary bootloader right which comes after u-boot menu.

    As a first step, I want so the the u-boot prompt. Is it mandatory to copy MLO as well to see the u-boot prompt? As per my understanding the flow is

    ROM BL-> U-Boot -> MLO -> Linux Kernel

  • 0 in reply to matt hardy
    TI__Guru**** 169600 points

    Hi Matt,

    Rom-->MLO-->U-boot-->Linux Kernel that is the right sequence.

    Please copy MLO as wll. SPL is secondary program Loader, ROM is the primary loader.

    So MLO is before u-boot.img.

    Thanks,
    Keerthy

  • 0 in reply to Keerthy J
    Prodigy 60 points

    Also If i need to tracedown the files used for building of MLO and u-boot for the same devkit which all files I need to look into. There are lots of files in source code and I am getting confused with which c file to start with to understand the MLO and u-boot initialization process.

  • 0 in reply to matt hardy
    TI__Guru**** 169600 points

    Matt,

    http://xillybus.com/tutorials/uboot-hacking-howto-3

    You can navigate through the code yourself with pointers given in the above link.

    I am closing this thread and i believe you have already resolved the issue.

    - Keerthy