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AM620-Q1: Concept clarification for MCU only mode base on SDK 11.0

Gibbs Shih
Expert 5285 points
Part Number: AM620-Q1

Tool/software:

Hi, Dear Expert

Reference this section, 3.3.5.5. MCU Only

https://software-dl.ti.com/processor-sdk-linux/esd/AM62X/11_00_09_04/exports/docs/linux/Foundational_Components/Power_Management/pm_low_power_modes.html

 Few question. 

(1) Follow these test steps in MCU only MODE, MCU SS will keep working, and main core (A53, Linux) will go to sleep, is it right? (y/n)

(2) Because try to avoid linux resource table (RPMSG resource table) backup workaround, MCU only mode recommand accompany with FFI? (y/n)

(3) Can any GPIO wakeup main core (A53, Linux) in mcu onlyu mode?(y/n)

(4) We confuse this item,

Base on current SDK (v11.0), we do not support mcuss wakeup A53, is it right?(y/n)

Do we have any schedule to release this patch?

 

Thank You Very Much

Gibbs

  • 0
    TI__Mastermind 46626 points

    Hello Gibbs,

    I am looking at your queries and you may expect reply in one or two days .

    Regards,

    Anil.

  • 0 in reply to Swargam Anil
    TI__Expert 5285 points

    Hi, Anil

    Any Update?

    Thank You

    Gibbs

  • 0 in reply to Gibbs Shih
    TI__Mastermind 18380 points

    Hi Gibbs,

    This just got assigned to me.

    Gibbs Shih said:
    (1) Follow these test steps in MCU only MODE, MCU SS will keep working, and main core (A53, Linux) will go to sleep, is it right? (y/n)

    Correct, for MCU Only mode, the MCU subsystem will remain online to run an application and use its peripherals.

    Gibbs Shih said:
    (2) Because try to avoid linux resource table (RPMSG resource table) backup workaround, MCU only mode recommand accompany with FFI? (y/n)

    Can you explain what FFI means in this context?

    Gibbs Shih said:
    (3) Can any GPIO wakeup main core (A53, Linux) in mcu onlyu mode?(y/n)

    Yes.

    Gibbs Shih said:
    Base on current SDK (v11.0), we do not support mcuss wakeup A53, is it right?(y/n)

    MCU Only does work. Please see the command directly above where you circled. The command for entering MCU only mode changed. That note is just to indicate that the old command doesn't work at this moment.

    Best Regards,

    Anshu

  • 0 in reply to Anshu Madwesh
    TI__Expert 5285 points

    Hi, Anshu

    Thanks you replies.

    Q3/A3 : >> Can you explain what FFI means in this context?

    FFI, Freedom From Interference. software isolation between MAN domain and MCUSS

    This is "concept clarification", base on function safety requirement for "automotive" application.

    Once MCU Only mode operation, we "should" ask FFI enable, isn't?

    Here is my idea,

    * We can enable MCU Only mode w/o FFI, but it should be have some safety concern

    * We can enable MCU Only mode w/ FFI (MCU isolation), MCU use ESM to monitor main domain error exception or reset A53 core once error detected. 

    Because main domain and MCUSS already in FFI (MCUSS isolation), and there should be no IPC communication between these two domains, so I think it does not need to care about IPC resource table recover issues.

    If I say anything wrong, pls correct me.

    Thank You Very Much

    Gibbs

  • +1 in reply to Gibbs Shih
    TI__Mastermind 46626 points

    Hey Gibbs,

    I will provide the reply to the above query.

    The above understanding is correct.

    With MCU core isolation, either the A53 core crash can be routed to the MCU core via ESM or the A53 core crash can also be detected over the IPC.

    If they go with the IPC, yes, the resource table can be recovered for every MAINDOMAIN RESET.

    If they don't want to go with the IPC, then they choose WDT. 

    IPC Mechanism:

    The Linux core sends periodic "heartbeat" messages to the M4F core.

    If the M4F core fails to receive these messages within a specified time frame, it can initiate a reset of the Linux core.


    Advantages:

    Simplifies system architecture by leveraging IPC for crash detection.


    Disadvantages:

    IPC uses DDR memory, necessitating M4F core configuration in isolated mode with monitoring capabilities.

    This setup allows MCU domain access to MAIN domain peripherals, preventing full isolation of the M4F core.


    Watchdog and Error Handling Module:

    Enable the watchdog interrupt on the A53 core.
    Route the watchdog interrupt to the MAIN ESM (Error Signaling Module) and propagate all MAIN ESM errors to the MCU ESM.
    MAIN ESM initialization is managed by the DM R5F core, while MCU ESM initialization is handled by the MCU core.


    Advantages:
    Allows the M4F core to be configured in fully isolated mode.


    Disadvantages:
    Adds software complexity due to ESM initialization procedures

    Regards,

    Anil.