AM6442: Am64x EVK understanding for Linux + FreeRTOS configuration

Radhika Pradeep

Part Number: AM6442

Hi,

I am using the AM64x EVK as a base for my custom board. I would like to clarify some of the questions based on my understanding of the system. From the AM64x Sitara Processor datasheet and the SDK packages, I could gather the following:
1. The A53 core runs Linux obtained from the Processor-SDK-Linux package
2. EVK also has 2 dual core R5's & 1 M4. It can run FreeRTOS or NoRTOS based on MCU-PLUS-SDK

It would be really helpful if you could share some info with regards to the following:

1. Does each core (2 * R5's & 1 * M4) run FreeRTOS ? or is it a single FreeRTOS maintaining all the cores and assigning tasks on each core ?
2. It is per my understanding that the default Linux in A53 cannot access the peripherals marked with 'MCU_' like 'MCU_i2c0'. Is this correct ?
3. Is it possible for the Linux in A53 to access these 'MCU_' peripherals with device tree modification or is it kind of locked to the other MCU cores ? I dont think it's practical to make the dts modification, but just out of curiosity.
4. The Am64x MCU + SDK documentation describes about accessing the SoC peripheral in this link :http://software-dl.ti.com/mcu-plus-sdk/esd/AM64X/07_03_00_19/exports/docs/api_guide_am64x/DRIVERS_PAGE.html . Is this related to the 'MCU_' peripherals itself or is access to all peripherals possible ?
5. How do I set up the EVM for Linux + FreeRTOS booting ? I am guessing that I have to flash Linux as per the Linux SDK documentation and flash FreeRTOS as per the MCU plus documentation and the MLO + u-boot takes care of booting both the OS's ?
6. Does the DMSC boot all R5 cores and then boots A53 as per the diagram in http://software-dl.ti.com/processor-sdk-sitara/esd/am64x/latest/exports/docs/linux/Foundational_Components/U-Boot/UG-General-Info.html ?
7. If so, then how is the M4 core booted ? Is it along with the R5 cores ?
8. I am assuming that the MLO and u-boot build from Linux SDK is capable of the booting as described in point 5. Is this correct or could you point me to the correct documentation ?

Any help is appreciated

Thanks and Regards

over 4 years ago

+1 Nick Saulnier over 4 years ago

TI__Guru** 100960 points

Hello,

MCU_peripherals:
Linux is capable of using these peripherals with a device tree modification. We add the MCU_peripherals to the Linux device tree in the future SDK 8.0 release. Remember that each peripheral should have only one core controlling it at a time. So MCU_peripherals will be disabled in the Linux device tree by default. Then you could enable the peripherals that you wanted Linux A53 to own instead of being owned by the R5s. See this thread for details:
https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1006780/am6442-using-mcu_i2c-in-linux

We might have to reassign your thread a couple of times to cover all of your questions. I am assigning your thread to our boot owner now.

Regards,

Nick

0 Radhika Pradeep over 4 years ago in reply to Nick Saulnier

Prodigy 80 points

Hi Nick ,

Thanks for your response.

We will try and test the device tree modifications.

Could you please update on the timeline of the official release of SDK 8.0.

Thanks and regards,

Radhika

+1 Hong Guan64 over 4 years ago in reply to Radhika Pradeep

TI__Guru 68420 points

Hi Radhika,
AM64x Linux SDK 8.0 release is currently scheduled for July-31-2021.
I added comments on the questions #5 to #8 regarding AM64x Linux SDK.
5. The Linux boot flow is described in
software-dl.ti.com/.../UG-General-Info.html
6. Yes, DMSC/Main_R5 cores work together to load, start rest of cores on the SoC.
TI SYSFW running on DMSC provides TISCI APIs for Resource Management(RM), Power Management(PM), and Security Management(SM).
There’s online TISCI user guide downloads.ti.com/.../
7. DMSC/Main_R5 core are responsible to load/start rest of cores, including M4.
8. Yes, u-boot/Linux SDK is described in
software-dl.ti.com/.../index_Linux.html
Best,
-Hong