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[FAQ] J784S4XEVM: How to enable main domain watchdog?

Part Number: J784S4XEVM
Other Parts Discussed in Thread: TDA4VM

The j721e/TDA4VM has SOC watchdog enabled. How to enable the same on J784s4?

  • Hello,

    Watchdog enabling needs 3 main modules:

    1. Watchdog driver & DT nodes
    2. SOC ESM
    3. PMIC ESM

    #2 & #3 are enabled in U-Boot.
    #1 is enabled in Linux.

    This is the wiring to route the Main domain ESM events(including watchdog) to PMIC.

    So j784s4 has 3 instances of ESM. Main, MCU & WKUP domain ESM
    respevtively. For the main domain ESM event to propagate to
    PMIC the event needs to be routed via MCU ESM & then MCU ESM
    needs to route the event to WKUP ESM & finally to PMIC.


    Below is the patch set on top of 8.6 SDK U-Boot directory:


    Steps to compile U-Boot with ESM support & install to SD card:

    cd $PSDK_Linux/board-support/u-boot-2021.01+gitAUTOINC+62a9e51344-g62a9e51344
    tar xvf j784s4-u-boot-esm.tar
    git am j784s4-u-boot-esm/*
    cd ../..
    make u-boot
    cp board-support/k3-image-gen-2022.01/tiboot3.bin board-support/u-boot_build/a72/tispl.bin board-support/u-boot_build/a72/u-boot.img /media/$USER/boot

    The Linux RTI watchdog DTS nodes addition patch here:


    Download the above patch to Linux folder of the SDK.

    cd $PSDK_Linux/board-support/linux-5.10.162+gitAUTOINC+76b3e88d56-g76b3e88d56
    git am 0001-arm64-dts-ti-k3-j784s4-main-Enable-the-Main-domain-R.patch
    cd ../..
    make linux-dtbs
    sudo make linux-dtbs_install

    With that the watchdog reset is functional.

    Best Regards,