RAM Loading example code

[Sathishkumar-rk]

Dear Team,

I'm new to the MCUBoot project, Is it possible to use the RAM Loading feature in MCUBoot on mimxrt1060-evk? Is there any example code for reference? I was trying to use the MCUBoot with zephyr project.

Regards,
Sathishkumar K

[d3zd3z]

I'm not aware of any sample code for it. The RAM loading is fairly new, and at least most of the targets I work with don't have enough RAM for me to really test it.

[DerekSnell]

Hi @Sathishkumar-rk ,
I suggest you use a debugger, and step through the MCUboot code to diagnose what is causing this bus fault. For debugging a Zephyr application on the RT1060, these Hands-On Labs detail how to use GDB or the MCUXpresso IDE. Or this blog provides detailed steps for using Segger's Ozone debugger.

Some initial thoughts that come to my mind, your menuconfig settings appear to be copying to SDRAM at 0x8000_2000. The SEMC needs to be initialized for SDRAM first before accessing the SDRAM. With the Zephyr applications for RT10xx, this SEMC initialization is typically configured in the DCD, and the ROM bootloader will configure the SDRAM before executing the application. You should be able to confirm easily if the MCUboot application is able to update the SDRAM.

Also, your bus fault shows an invalid address for the PC causing the fault at 0x0207_F020. That address does not appear to be valid looking at the RT1060 memory map. So why is the PC trying to execute from there? Using a debugger will help you track that down.

Best regards

[Sathishkumar-rk]

@DerekSnell Thanks for update. Yes, you are right problem was when i using sram location before initialization (RT1160 doesn't have the initialization details of sram).

For time being i used DTCM location (0x20004000) instead of sram location (0x80002000), since I'm working sample applications which has low memory consumption. In DTCM location i could able to run the application.

Now, I'm flashed two different version of application. Slot-0 will have lower version and Slot-1 will have the higher version. rsp pointer is getting updated with Slot-1 image but Slot-0 application getting executed, I think need to change something in do_boot API in main.c file ? any thought on this?

[Sathishkumar-rk]

Hi @DerekSnell @danieldegrasse @d3zd3z

Please give your thoughts on this issue.

I have attached the main.c file of mcuboot project code.

Is there anything I need to change on do_boot API to execute the latest version of image?

I suspect the new version of image address is updated on rsp but while executing Slot-0 image getting started, this make me thing about whether the copied image on RAM is getting executed or is still executing application from Flash itself?

main.zip
config.zip

Image version of both slot:

Ram load information:

Regards,
Sathishkumar K

[Sathishkumar-rk]

Hi @DerekSnell @danieldegrasse,

How to initialize the SEMC for accessing SDRAM. I'm using mimxrt1160_evk_cm7 board & zephyr RTOS for my development work.

Your input will be really helpful on developing ram loading upgrade mode.

Regards,
Sathishkumar K

[DerekSnell]

Linking to your other discussion on this topic zephyrproject-rtos/zephyr#48242 (comment)