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DRA829 Boot process question

Xiaolei Li
Prodigy 20 points

Other Parts Discussed in Thread: DRA829, TDA4VM

my question is about DRA829 boot process, documents I have referred is shown below:

"Processor SDK Linux for J721e 07_03_00 "

"J721E DRA829/TDA4VM Processors Silicon Revision 1.1 Texas Instruments Families of Products_Technical Reference Manual"

I just pick up the boot process flow from two document,

first question:

What is the usage of the file "tiboot3.bin"? if it is used for loading R5 SPL? [if the SPL is equivalent as SBL?]

second question:

look at the step "MCU Reboots with Loaded image" in the right side flow, what happened at this step? [if R5 ROM code use tiboot3.bin which had been downloaded in SRAM to loading R5 SBL(initial software)]

  • +1
    TI__Guru**** 169720 points
    Xiaolei Li said:

    What is the usage of the file "tiboot3.bin"? if it is used for loading R5 SPL? [if the SPL is equivalent as SBL?]

    tiboot3.bin itself contains the R5 SPL.

    File: board/ti/j721e/README under $SDK/board-support/u-boot* folder

    SPL is equivalent to R5 SBL. That is correct but SPL has more features as it comes from the standard U-Boot offering.

    SBL is based on RTOS & SPL is based on the U-Boot. So they are part of different boot flows. It is either R5 SPL or R5 SBL. One of them runs
    on the MCU R5F.

    Xiaolei Li said:
    look at the step "MCU Reboots with Loaded image" in the right side flow, what happened at this step? [if R5 ROM code use tiboot3.bin which had been downloaded in SRAM to loading R5 SBL(initial software)]

    R5F RoM loads the R5F SPL(tiboot3.bin) from the boot media to the SRAM and starts executing the SPL. The R5F SPL then initializes DDR.

    If no further questions then please click on verify answer.

    Best Regards,
    Keerthy

  • 0 in reply to Keerthy J
    Prodigy 20 points

    Hi, Keerthy

    one more question, for the customer bootloader for R5F, if it is R5F SPL or SBL responsibility to load into SRAM, and then execute the customer bootloader?

  • +1 in reply to Xiaolei Li
    TI__Guru**** 169720 points
    Xiaolei Li said:
    one more question, for the customer bootloader for R5F, if it is R5F SPL or SBL responsibility to load into SRAM, and then execute the customer bootloader?

    RoM will load custom SBL or SPL from the boot media to SRAM. SBL can then load the other firmware.

  • 0 in reply to Keerthy J
    Prodigy 20 points

    Hi, Keerthy

    Can we modify SBL or SPL and add new feature on it? for example, when we do A/B partition OTA, we shall check a 'available state' of A and B first during boot, and then decide run which part of system (A or B).

  • 0 in reply to Xiaolei Li
    TI__Guru**** 169720 points

    Hi,

    Customer bootloader should either be SBL based or SPL based. What is the customer's boot flow? Are they using SBL or SPL?
    Where is the customer bootloader expected to run, as in which core?

    - Keerthy