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PROCESSOR-SDK-J784S4: Boot from eMMC from BOOT paritions

Naradham Dharanija
Prodigy 130 points
Part Number: PROCESSOR-SDK-J784S4

Tool/software:

Hi Team,

    I want to boot from eMMC UDA partitions in my J784S4 custom board.As part of that I am writing boot contents to first partition of UDA i.e,/dev/mmcblk0p1 nd also enabled PARTCONFIG to user mode as shown in attached figure.

  After writing the contents successfully, I changed the boot switches to eMMC mode and powering on the board but it resulting blank screen.
And I want to specify that we're having single/same boot switch configuartion for both BOOT,UDA modes of eMMC booting.

FYI, I am able to write/read contents to/from UDA partitions of eMMC for some other purposes and also able to mount the rootfs from eMMC.

And I compared the hardware schematics of my custom board with J784S4 .But I didn't find any notable difference.

   So, what can be the possible reasons to happen this and what can be the fix for that?

  • 0
    TI__Mastermind 48253 points

    Hello Naradham,

    Can you share the Boot mode pin setting for the eMMC boot? Please refer to Chapter 4 - Initialization in the TRM for details. ( See Chapter 4.3 Boot Mode Pins)

    Thanks.

  • 0 in reply to Praveen Rao
    Prodigy 130 points

    Hello Praveen Rao,

     Following are the boot mode pin settings for the eMMC boot in my custom board

     Thanks.

  • 0 in reply to Naradham Dharanija
    TI__Genius 11810 points

    Hi Dharanija,

    Before booting from eMMC,can you enter into uboot and type the below commands.

  • 0 in reply to Gokul Praveen
    Prodigy 130 points

    Hello Praveen,

    Thank you for the response!

    I have given the following commands through U-Boot command line interface by staying in SD card boot mode.

    mmc partconf 0 1 7 1

    mmc bootbus 0 2 0 0

    After that turned off power and changed boot switches to eMMC mode as mentioned in above table and reset the power but still it's resulting blank screen.

  • 0 in reply to Naradham Dharanija
    TI__Genius 11810 points

    Hi Naradhan,

    Can you try connecting to a debugger,connect to MCU R5 core and try getting the address the PC register is pointing to,as it could be the case that the BOOT ROM is failing.

    Regards

    Gokul

  • 0 in reply to Gokul Praveen
    Prodigy 130 points

    Hello Praveen,

       Thank you for the reply and I will check the things that you mentioned. 

       Before that please help me to get clarification from your end for following things!!

    1.Where can I find the boot switch settings for eMMC boot and UDA modes of J784S4 EVM in it's linux SDK?

    2. I tried to boot from BOOT0 partition of eMMC.For that I have tried with the following set of commands by staying in SD card mode.

     

    I have calculated the block offsets and block counts based on the sizes of my individual boot files (tiboot3.bin, tispl.bin, and u-boot.img) as mentioned in attached figure.

    Could you please confirm whether altering the block offsets impacts the boot process in any way?

  • 0 in reply to Naradham Dharanija
    TI__Genius 11810 points

    Hi Naradham,

    Naradham Dharanija said:
    1.Where can I find the boot switch settings for eMMC boot and UDA modes of J784S4 EVM in it's linux SDK?

    Its not actually mentioned anywhere in the linux SDK.However you can follow the below mentioned settings which is universal across all jacinto devices.

    Naradham Dharanija said:
    Could you please confirm whether altering the block offsets impacts the boot process in any way?

    Actually the block offsets from which the bootloaders fetch the code are fixed .Can you help us with the SDK version which you are using, as the offsets are different based on the version.If using 10.0 SDK version,then you can follow the below commands to copy to boot 0 partition from sd card:

  • 0 in reply to Gokul Praveen
    Prodigy 130 points

    Hi Praveen,
         1. SDK version I am using is ti-processor-sdk-09_02_00 and pls suggest me the block offsets accordingly.

         2.BOOT capacity : 4 MiB ENH of eMMC that I am using in my J784S4 custom board.And that boot size is not sufficient If I follow the block offsets provided in TI website.( https://software-dl.ti.com/jacinto7/esd/processor-sdk-linux-j784s4/09_02_00_05/exports/docs/linux/Foundational_Components/U-Boot/UG-Memory.html#partitioning-emmc-from-u-boot)

      So, I want to know is there any way to change the size of Boot partition through software?

  • +1 in reply to Naradham Dharanija
    TI__Genius 11810 points

    Hi Naradham,

    Naradham Dharanija said:
      So, I want to know is there any way to change the size of Boot partition through software?

    Actually there is no way to change the size of the boot partition as it is decided by the emmc manufacturer according to the EMMC standard.

  • 0 in reply to Gokul Praveen
    Prodigy 130 points

    Hi Team,

     As continuation to previous query, I want to boot from eMMC of UDA . For that I have set the boot switches to eMMC mode and written boot contents to respective partition(mmcblk0p1) . But still it's not booting and resulting blank screen as output after powering on the board.

    What additional aspects should I investigate to debug this issue further, such as U-Boot settings or other relevant configurations?

    FYI, I am able to successfully mount the rootfs from UDA of eMMC.

    Regards,

    Dharanija

  • 0 in reply to Naradham Dharanija
    TI__Genius 11810 points

    HI Naradham,

    Naradham Dharanija said:
    What additional aspects should I investigate to debug this issue further, such as U-Boot settings or other relevant configurations?

    If you are able to succesfully mount rootfs,then it is mostly the problem with the boot switch settings on your custom board.Can you try connecting to a debugger,connect to MCU R5 core and try getting the value of the CTRLMMR_WKUP_DEVSTAT register because the BOOT ROM sets the boot mode based on that value.The value of this register is mapped to the boot switch settings.Hence ,if that value is not correct,the only cause would be that the boot switch is not setting the correct value corresponding to emmc UDA in the DEVSTAT register hence causing the boot to fail because the  BOOT ROM is fails.

    Also have you set the below mentioned settings in uboot before booting from UDA partition.