Skip to main content
AHayo.1
Associate II
April 27, 2021
Solved

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

  • April 27, 2021
  • 2 replies
  • 1604 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

2 replies

Olivier GALLIEN
Olivier GALLIENBest answer
ST 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

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.
AHayo.1
AHayo.1Author
Associate II
May 3, 2021

Yes, thank you very much !

Nice day !