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AM6548: ATF/OPTEE disable

Joey Fang
Intellectual 295 points
Part Number: AM6548


Hi TI team,

Currently, I am testing the AM65x industrial development kit.

The SDK version I use is ti-processor-sdk-linux-rt-am65xx-evm-06.02.00.81.

During the boot flow, the ATF and OPTEE will be loaded, and then the A53 SPL and u-boot image be loaded subsequently.

    |         |         |                       |     +-----------+     |
|    |         |---------|-----------------------|---->| Reset rls |     |
|    |         |         |                       |     +-----------+     |
|    |  DMSC   |         |                       |          :            |
|    |Services |         |                       |     +-----------+     |
|    |         |<--------|-----------------------|---->|*ATF/OPTEE*|     |
|    |         |         |                       |     +-----------+     |
|    |         |         |                       |          :            |
|    |         |         |                       |     +-----------+     |
|    |         |<--------|-----------------------|---->| *A53 SPL* |     |
|    |         |         |                       |     +-----------+     |
|    |         |         |                       |     |   Load    |     |
|    |         |         |                       |     | u-boot.img|     |
|    |         |         |                       |     +-----------+     |
|    |         |         |                       |          :            |
|    |         |         |                       |     +-----------+     |
|    |         |<--------|-----------------------|---->| *U-Boot*  |     |
|    |         |         |                       |     +-----------+     |
|    |         |         |                       |     |  prompt   |     |
|    |         |         |                       |     +-----------+     |
|    +---------+         |                       |                       |

However, in our future use case, we don't have security demand.

Is it possible to skip the step of loading ATF and OPTEE , and load A53 SPL directly?

if yes, could you tell me how to patch the u-boot?

Thanks

  • 0
    TI__Guru**** 163920 points

    Hello,

    ATF is must and should in the boot flow. Following reasons:

    1) It implements all the ARM erratas.
    2) It does the initial GIC configuration.
    3) SMP related configuration is also done by ATF.

    We strictly advise not to bypass ATF otherwise you will have to implement most of ATF code in A53 SPL.

    However Optee can be bypassed.

    If you look at the ATF Build command in board/ti/j721e/README:
    make CROSS_COMPILE=aarch64-linux-gnu- ARCH=aarch64 PLAT=k3 TARGET_BOARD=generic SPD=opteed

    You can just remove SPD=opteed

    So your ATF build command becomes:
    make CROSS_COMPILE=aarch64-linux-gnu- ARCH=aarch64 PLAT=k3 TARGET_BOARD=generic

    This will bypass Optee and jump to A53 SPL directly from ATF.

    Hope this answers all your questions. If yes the please resolve the thread.

    Regards,
    Keerthy

  • 0 in reply to Keerthy J
    Intellectual 295 points

    Hi Keerthy,

    It's clear. Thank you so much.