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TDA4AL-Q1: TDA4AL: Allocate dma-buf from dma-heap, error occurred during open of dma-heap buf.

Srinivas N
Prodigy 40 points
Part Number: TDA4AL-Q1

Tool/software:

SDK Deatials:
Processor SDK Linux for J7S21S2

Board details:
J7S21S2 EVM Board

Hi TI Experts,

I am exploring around AM62x. I'm testing zero copy's functionality based on git.ti.com/.../rpmsg_char_zerocopy.git.

I am facing below issue while trigger open function from below API.

Failed to open /dev/dma-buf-phys: -2

Error snapshot:

  • 0
    TI__Guru**** 155900 points

    Hi Srinivas,

    Which exact SDK version are you using? 

    Also I belive you are not using am62x as the Linux prompt shows j721s2. Please confirm. 

    Best Regards,

    Keerthy 

  • 0 in reply to Keerthy J
    Prodigy 40 points

    Hi Keerthy,

    Please see my response below 

    Which exact SDK version are you using? 

    I am using SDK Version 10_00_00.

    Also I belive you are not using am62x as the Linux prompt shows j721s2. Please confirm.

    Yes, I am using j721s2-evm. 

    Best Regards,

    Srinivas

  • 0 in reply to Srinivas N
    TI__Mastermind 39035 points

    Hi srinivas,

    Please allow us some time to check.

    Regards

    Tarun Mukesh

  • 0 in reply to Tarun Mukesh Puvvada
    TI__Guru** 102165 points

    Hi Srinivas,

    The rpmsg_char_zerocopy example is only supported on the Sitara AM64, AM62, AM62A devices, which have a very different number of cores  (and as a result memory map for remote processors) compared to J721S2.

    The examples are also typically designed to work with a corresponding counter-part firmware example. If you are booting the TI EVM with the SDK default root filesystem, then the firmwares used are meant to run the Vision Apps applications, not a standalone IPC example, let alone an application that is not even supported on J721S2 or other TDA4 devices.

    The RTOS-side example code is also based on MCUPlusSDK, whereas the s/w stack on J721S2 is based on PDK.

    You may want to run the VIsionApps level IPC Test that works with the Vision Apps firmwares.

    regards

    Suman

  • 0 in reply to Suman Anna
    Prodigy 40 points

    Hi Suman Anna,

    Please find my requirements below.

    1. Exchange big data around 2kb between A72 and R5F Cores.

    2. A72 will run HLOS(Linux) and on R5F core BareMetal application will run.

    To achieve above requirements, we need to have shared memory (DMA Heap) between these cores as per the user guide Processor SDK RTOS J721S2 10_00_00   and section number 9.4.6.1.

    When I was searching e2e thread related to shared memory example, I came across zero-copy example. I ported the Linux application and RTOS application to TDA4AL SOC. 

    Please let me know if I can continue using zero-copy ported example to achieve my requirements or else is there any other example application for requirements specified above?

    Also, confirm me know if the shared memory technique works for R5F BareMetal application also.

    Note: I am specifically looking example for R5F core not for DSP core.

    Regards,

    Srinivas

  • 0 in reply to Srinivas N
    TI__Guru** 102165 points

    Hi Srinivas,

    Srinivas N said:
    1. Exchange big data around 2kb between A72 and R5F Cores.

    This is very standard usage of exchanges large buffers between A72 and R5F. The whole of TI OpenVX graph scheme in fact is built on top of this concept.

    Srinivas N said:
    2. A72 will run HLOS(Linux) and on R5F core BareMetal application will run.

    Is the R5F baremetal just your demo usage, or your actual product application need? The IPC protocol is generally agnostic of the OS running on the R5F cores, and we have PDK IPC examples supporting FreeRTOS, SafeRTOS and baremetal. The R5F processors typically run an RTOS to manage all its various threads though, and baremetal is not a very standard usage model in Automotive markets.

    Srinivas N said:
    Please let me know if I can continue using zero-copy ported example to achieve my requirements or else is there any other example application for requirements specified above?

    This is fine in general, but it all depends on the overall environment you are using. If you are booting the TI SDK rootfs with the default firmwares on all other cores, they are running the OpenVX stack with the Linux memory carveouts specifically made to work with those firmwares. If you are doing a one-off addition, you might be conflicting with existing firmwares and memory-maps.

    regards

    Suman

  • +1 in reply to Suman Anna
    Prodigy 40 points

    Hi Suman Anna,

        I would like to thank you for your response and support.

        The issue related to DMA Buf  (Failed to open /dev/dma-buf-phys: -2) on Zero copy example is resolved now.

        On A72 "dma-buf-phys" driver was not enabled in the linux kernel, which was downloaded from TDA4AL software tools section.

        We got the "dma-buf-phys" driver from our older project and included in the kernel and compiled, after these steps A72 side the dma buf related issues are resolved and on R5F side we are using R5F_MAIN1_1 core and ported the RTOS example given in zero_copy example source to bare-metal application on R5F.

       Now, both A72 with Linux, and R5F with Bare-Metal app are able to exchange big data between them.

       Find the snapshot of the tested example below.

    Thanks & Regards,

    Srinivas