Can't run zephyr application from SDRAM on RT1060-EVKB

[ofirshe]

Hey,

I wanted to link my application to SDRAM and then download the zephyr.elf using the debugger for debug purposes (can't debug my application from the FLASH).
I tried to run my zephyr application from the SDRAM using CONFIG_XIP=n and CONFIG_NO_OPTIMIZATIONS=y, but the application hangs in arm_mpu_init(). In order to overcome this, I set CONFIG_ARM_MPU=n but I get warning regarding stack protection.
When will execution from SDRAM be supported by zephyr ?

Best Regards,
Ofir.

[raghulshanmuganathan]

I can run zephyr.elf from a debugger by removing the following lines from Kconfig.defconfig in my custom board directory (MIMXRT1060).

choice CODE_LOCATION
default CODE_FLEXSPI
endchoice

It defaults to CODE_ITCM for me if I remove it. You can try the same maybe!

[ofirshe]

That's the output from the debuuger:
loadfile "zephyr.elf"
Loaded section .ARM.exidx: 0x0000472C ~ 0x00004733 (size 0x8)
Loaded section rom_start: 0x00000000 ~ 0x000002BF (size 0x2C0)
Loaded section text: 0x000002C0 ~ 0x0000472B (size 0x446C)
Loaded section .ARM.exidx: 0x0000472C ~ 0x00004733 (size 0x8)
Loaded section initlevel: 0x00004734 ~ 0x000047CB (size 0x98)
Loaded section devices: 0x000047CC ~ 0x00004903 (size 0x138)
Loaded section sw_isr_table: 0x00004904 ~ 0x00004E03 (size 0x500)
Loaded section device_handles: 0x00004E04 ~ 0x00004E5D (size 0x5A)
Loaded section ctors: 0x00004E5E ~ 0x00004E6B (size 0xE)
Loaded section rodata: 0x00004E6C ~ 0x0000662B (size 0x17C0)
Loaded section datas: 0x20000000 ~ 0x20000137 (size 0x138)
Loaded section device_states: 0x20000138 ~ 0x2000016B (size 0x34)
Loaded section k_heap_area: 0x2000016C ~ 0x20000183 (size 0x18)
Entry point 0x00001501

[ofirshe]

and if you can send me your custom board folder I'll be grateful.

[DerekSnell]

Hi @ofirshe ,
When I changed the Kconfig symbols to execute from ITCM, but left the data in SDRAM, I had faults when the SDRAM was accessed. This was caused when I used the debugger to load and start the application rather than booting from flash. This discussion explains the reason for this, and options to workaround it.

[ofirshe]

Hey @DerekSnell,

I understand the problem that when my application go through the RAM, it skips all the SDRAM initialization which occurs from the Boot Rom (DCD). Thus, according to your response, I must concatenate somehow the MCUBoot at the start to my application.

I have many questions:

1. How can I build the MCUBoot with my application in a single elf file ?
2. After generating that elf, will I be possible to upload that from the debugger ? Because I believe it includes some writes to FLASH and it's Read Only Memory (might get bus error).

what I've done so far in my custom board folder:

1. Change Code location to CODE_ITCM in Kconfig.defconfig
2. Change sram location in dts file - changed 'zephyr,sram = &sdram0;' to 'zephyr,sram = &dtcm;'

Can you please write down here all the steps I have to do to compile my application with the MCUBoot included in ? I'll appreciate that a lot.

Or maybe is there another shorter workaround which I can do ?

Thanks you very much,
Ofir.

[DerekSnell]

Hi @ofirshe ,
I shared the detailed steps for this at this other discussion, because that discussion already has many details about using the TCMs, and the considerations when booting.

Please give this a try, and let us know how it works for you.