AM625: Regarding the "Flash SOC Initialization Binary" for M4F

Koichiro Tashiro

Part Number: AM625
Other Parts Discussed in Thread: UNIFLASH

Tool/software:

Hi,
I got below questions from my customer. Please answer them.

-----------------------------------------------------
[Background of the Question]
We are considering applying the M4F on the AM62x.
In the Web manual, for the M4F initialization procedure, the step "Flash SOC Initialization Binary" requires changing the boot mode using DIP switches, and then connecting the AM62x to a PC (which has the MCU SDK installed) via JTAG and UART to write the SOC binary.
https://software-dl.ti.com/mcu-plus-sdk/esd/AM62X/09_02_01_06/exports/docs/api_guide_am62x/EVM_SETUP_PAGE.html#EVM_FLASH_SOC_INIT

However, executing this procedure individually for every shipped product board can require a significant amount of time and effort. Therefore, we are wondering if it is possible to omit this step when applying the M4F to products.
Given this context, could you please clarify the following points?

Q1. What exactly does the "Flash SOC Initialization Binary" procedure do?
       What capabilities or states does it enable?
       What concerns or issues might arise if this step is omitted?
Even if the "Flash SOC Initialization Binary" procedure has not been performed, is it acceptable as long as the following log messages appear in the dmesg of Linux on the AM62x A53?

    [    0.000000] OF: reserved mem: initialized node m4f-dma-memory@9cb00000, compatible id shared-dma-pool
    [    0.000000] Reserved memory: created DMA memory pool at 0x000000009cc00000, size 14 MiB
    [    0.000000] OF: reserved mem: initialized node m4f-memory@9cc00000, compatible id shared-dma-pool
    
    [    5.897632] k3-m4-rproc 5000000.m4fss: assigned reserved memory node m4f-dma-memory@9cb00000
    [    5.906884] k3-m4-rproc 5000000.m4fss: configured M4 for remoteproc mode
    [    5.910385] k3-m4-rproc 5000000.m4fss: local reset is deasserted for device
    [    5.916753] remoteproc remoteproc0: 5000000.m4fss is available
    [    5.929384] remoteproc remoteproc0: powering up 5000000.m4fss
    [    5.929410] remoteproc remoteproc0: Booting fw image am62-mcu-m4f0_0-fw, size 511180
    [    5.938378] rproc-virtio rproc-virtio.0.auto: assigned reserved memory node m4f-dma-memory@9cb00000
    [    5.938577] rproc-virtio rproc-virtio.0.auto: registered virtio0 (type 7)
    [    5.938588] remoteproc remoteproc0: remote processor 5000000.m4fss is now up

Q2. If it is not possible to omit the "SOC Initialization Binary" procedure, for example, is there a way to replace this operation through command-line interactions from Linux on the A53?
-----------------------------------------------------

Thanks and regards,
Koichiro Tashiro

3 months ago

0 Nick Saulnier 3 months ago

TI__Guru** 101330 points

Hello Koichiro-san,

What boot flow is the customer using? SBL or SPL?

For more information, please refer to the AM62x academy
Multicore > booting > Boot flows: SPL vs SBL
https://dev.ti.com/tirex/explore/node?node=A__AZdBTlT8UK2hNwHKXaPieQ__AM62-ACADEMY__uiYMDcq__LATEST

I am not sure I understand the question. Is the customer asking about how to load firmware into the M4F during boot time?

If that is the question, please refer to the AM62x academy
Multicore > booting > Methods to initialize remote cores
https://dev.ti.com/tirex/explore/node?node=A__AXoA3i9lx8c-jH8btw5.pA__AM62-ACADEMY__uiYMDcq__LATEST

If the customer is asking about how to flash the filesystem and everything else onto their production boards, that is a different concept. I can send your thread to the correct team member if you want more information about that.

Regards,

Nick

0 Koichiro Tashiro 3 months ago in reply to Nick Saulnier

TI__Mastermind 22935 points

Hi Nick,

Please see below feedback from the customer.
----------------------
Thank you for your response.
This is related to the SPL. I believe it corresponds to the "SPL boot flow: Linux Remoteproc driver" described in the URL you provided.

To clarify, my question is not regarding the method of loading the M4F firmware during boot time.
More specifically, using the terminology from the documentation you provided, I would like to confirm whether the step "Flash SOC Initialization Binary" - as mentioned in the web manual (https://software-dl.ti.com/mcu-plus-sdk/esd/AM62X/09_02_01_06/exports/docs/api_guide_am62x/EVM_SETUP_PAGE.html#EVM_FLASH_SOC_INIT) - can be omitted when utilizing the Linux Remoteproc driver within the SPL boot flow.
----------------------

Thanks and regards,
Koichiro Tashiro

0 Nick Saulnier 3 months ago in reply to Koichiro Tashiro

TI__Guru** 101330 points

Hello Koichiro-san,

The Linux remoteproc driver is not related to flashing.

The customer's board will only have to be flashed once. After that, the filesystem will be on the board.

However, every single time the processor boots up, something will need to load firmware into the M4F before the M4F can start executing code. The Linux remoteproc driver is one tool to take the M4F binary that is stored on the board in the filesystem, and load the binary into the M4F core. With SPL boot, the other tool is the U-Boot rproc driver. The customer can refer to my links in the previous response for more information.

Regards,

Nick

0 Koichiro Tashiro 2 months ago in reply to Nick Saulnier

TI__Mastermind 22935 points

Hi Nick,

I will send you a few slides offline. In slides, the customer summarized their understandings and concerns.
Please check it and give your feedback.

Thanks and regards,
Koichiro Tashiro

+1 Nick Saulnier 2 months ago in reply to Koichiro Tashiro

TI__Guru** 101330 points

Hello Koichiro-san,

Thank you for sharing the offline slides.

Context about the design

For future readers, the plan for this design is to use a Linux filesystem stored on an SD card.

Writing a filesystem onto the EVM

In any design, the filesystem must be stored somewhere on the board.

If the filesystem is stored in NOR flash, NAND flash, or EMMC, then the filesystem can be flashed into that on-board memory using a tool like Uniflash. For more information about this flashing process, refer to
https://software-dl.ti.com/mcu-plus-sdk/esd/AM62X/09_02_01_06/exports/docs/api_guide_am62x/TOOLS_FLASH.html
and
https://software-dl.ti.com/mcu-plus-sdk/esd/AM62X/09_02_01_06/exports/docs/api_guide_am62x/GETTING_STARTED_FLASH.html

However, if you are storing your filesystem on an SD card before plugging the SD card into the production boards, then there is no need to flash the filesystem onto your board.

So why do the MCU+ SDK docs tell me to flash an SOC Initialization binary during the "Getting Started" section?

https://software-dl.ti.com/mcu-plus-sdk/esd/AM62X/09_02_01_06/exports/docs/api_guide_am62x/EVM_SETUP_PAGE.html#EVM_FLASH_SOC_INIT

Before you connect a debugger like CCS to a TI processor, some parts of the processor need to boot and be initialized.

If you are booting Linux on your SD card, then the Linux boot process will initialize all the clocks, power domains, etc that need to be running before CCS can attach to the processor.

However, if you are NOT booting Linux, then the MCU+ SDK documents how to flash a minimal bootloader to one of the on-board memories. Then you would modify your boot mode pins to select the on-board memory with the minimal bootloader, and let the bootloader initialize the processor before you attach CCS to the processor.

Regards,

Nick

0 Koichiro Tashiro 2 months ago in reply to Nick Saulnier

TI__Mastermind 22935 points

Hi Nick,

Thanks for your answer. The customer appreciated your detailed explanation.

Thanks and regards,
Koichiro Tashiro

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AM625: Regarding the "Flash SOC Initialization Binary" for M4F