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Visitor II
April 27, 2021
Solved

Where to find the device trees (*-a7-examples.dts or *-m4-examples.dts) ?

  • April 27, 2021
  • 1 reply
  • 1527 views

Hi,

I'm developping an application where we want the cortex-M doing some power management (with OpenAMP) and the cortex-A taking picture and saving it on SD card.

I have the STM32MP157A-EV1.

I used the OpenAMP_TTY_echo_wakeup sample that I modified for my need to do the power management. Everything is working fine if I boot in third mode (ie. stm32mp157c-ev1-m4-examples). However, I don't have any camera input as it's saying that /dev/video0 doesn't exist.

If I boot in second mode (ie. stm32mp157c-ev1-a7-examples), I've got a camera but I couldn't suspend at first (systemctl suspend), because I would get the following error :

PM: Device 40017000.dac:dac@1 failed to suspend: error -16

So, I commented every line of code linked to DAC and it worked (ie. I could have the OpenAMP and camera running at the same time). But it's not that great of a workaround. Ideally, I would want to update the device tree. Where could I find the initial device trees used so that I just can quickly modify them ?

I know they are stored in <path>/Developer-Package/stm32mp1-openstlinux-5-4-dunfell-mp1-20-11-12/sources/arm-ostl-linux-gnueabi/linux-stm32mp-5.4.56-r0/linux-5.4.56/arch/arm/boot/dts but I think it's the default one and I would like the stm32mp157c-ev1-m4-examples.dts and stm32mp157c-ev1-a7-examples.dts to make these minimal changes.

Note : I tried to get the dts from the /boot/dtb with dtc command but it's saying me there is a syntax error.

Best regards !

    This topic has been closed for replies.
    Best answer by Olivier GALLIEN

    Hi @AHayo.1​ ,

    stm32mp157c-ev1-m4-examples.dts and stm32mp157c-ev1-a7-examples.dts are indeed in the <path>/Developer-Package/stm32mp1-openstlinux-5-4-dunfell-mp1-20-11-12/sources/arm-ostl-linux-gnueabi/linux-stm32mp-5.4.56-r0/linux-5.4.56/arch/arm/boot/dts ... once you have applied the ST patches.

    Refer to README_HOW_To file in <path>/Developer-Package/stm32mp1-openstlinux-5-4-dunfell-mp1-20-11-12/sources/arm-ostl-linux-gnueabi/linux-stm32mp-5.4.56-r0 for complete installation of sources.

    Hope it help,

    Olivier

    1 reply

    Technical Moderator
    April 27, 2021

    Hi @AHayo.1​ ,

    stm32mp157c-ev1-m4-examples.dts and stm32mp157c-ev1-a7-examples.dts are indeed in the <path>/Developer-Package/stm32mp1-openstlinux-5-4-dunfell-mp1-20-11-12/sources/arm-ostl-linux-gnueabi/linux-stm32mp-5.4.56-r0/linux-5.4.56/arch/arm/boot/dts ... once you have applied the ST patches.

    Refer to README_HOW_To file in <path>/Developer-Package/stm32mp1-openstlinux-5-4-dunfell-mp1-20-11-12/sources/arm-ostl-linux-gnueabi/linux-stm32mp-5.4.56-r0 for complete installation of sources.

    Hope it help,

    Olivier

    AHayo.1Author
    Visitor II
    May 3, 2021

    Yes, thank you very much !

    Nice day !