nrf5340 custom board build issue: ninja.build not found

[frax84]

Hello everyone,

i am developing code (VS Code, Toolchain/SDK: 2.3.0)  for a custom board based on nrf5340. I have been able to build a simple hello_world + Serial DFU example based on this guide that i found on DevZone faking my custom board as a nrf5340DK. When i say "faking my board" i mean that i successfully built the code for nrf5340DK and flashed it to my CUSTOM BOARD (Segger J-Link connected to my custom board through SWD programming port). Now that i'm sure that my board can be programmed correctly, i'm trying to create my specific board in the "boards" folder. To get started, i used the VS code menu "Create a new board" and followed the procedure. The procedure created the correct folder with the needed files inside (my_board.dts, *defconfig, etc.). Unfortunately, when i tried to build the code for this board, the process fails with an error regarding missing info about sram0_shared. Analyzing the content of the nrf5340dk boards folder i found and added the following code to my_board.dts file:

reserved-memory {
		#address-cells = <1>;
		#size-cells = <1>;
		ranges;

		sram0_shared: memory@20070000 {
			/* SRAM allocated to shared memory */
			reg = <0x20070000 0x10000>;
		};
	};

After this i have been able to solve the sram0_shared issue. Unfortunately, this didn't happen to be enough to compile successfully. Now i'm stuck getting this error:

No fprotect backend selected

I tried looking again into "nrf5340dk" board directory, but i didn't find anything that gave me an hint.

I'm suspicious about my kconfig settings. Changing them a bit sometimes changes the error. Here you go the "my_board_defconfig":

# Copyright (c) 2023 Nordic Semiconductor ASA
# SPDX-License-Identifier: Apache-2.0

CONFIG_SOC_SERIES_NRF53X=y
CONFIG_SOC_NRF5340_CPUAPP_QKAA=y
CONFIG_BOARD_MY_BOARD=y

# Enable MPU
CONFIG_ARM_MPU=y

# Enable hardware stack protection
CONFIG_HW_STACK_PROTECTION=y

# Enable TrustZone-M
CONFIG_ARM_TRUSTZONE_M=y

# Enable console
CONFIG_CONSOLE=y

And my proj.conf:

# Enable mcumgr.
CONFIG_MCUMGR=y

# Enable most core commands.
CONFIG_MCUMGR_CMD_IMG_MGMT=y
CONFIG_MCUMGR_CMD_OS_MGMT=y

# Ensure an MCUboot-compatible binary is generated.
CONFIG_BOOTLOADER_MCUBOOT=y

# Enable the serial mcumgr transport.
CONFIG_MCUMGR_SMP_UART=y

# Disable UART Console and enable the RTT console
CONFIG_UART_CONSOLE=n
CONFIG_RTT_CONSOLE=y
CONFIG_USE_SEGGER_RTT=y

# Some command handlers require a large stack.
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=4096

Any idea?

Thank you for your time

Edit: typos and more info about my Kconfig settings

[frax84]

Discovered something that could provide useful. I back-tracked the fprotect error on the  Cmake file where it is generated. I studied the possible if conditions and from what i searched this line should be true but it is not:

if (CONFIG_HAS_HW_NRF_SPU)
  set(FPROTECT_SRC fprotect_spu.c)

Based on KConfig reference for CONFIG_HAS_HW_NRF_SPU the selection chain should be

CONFIG_HAS_HW_NRF_SPU ---(selected by)---> SOC_NRF5340_CPUAPP ---(selected by)--->  SOC_NRF5340_CPUAPP_QKAA

where the last symbol is already present in my defconfig file. Even the dependencies of the symbols are fine, so i really don't get why that if condition is not triggered :S.

Edit: Added links for improved readability

[Sigurd Hellesvik]

Hi,

CONFIG_HAS_HW_NRF_SPU is a Kconfig option automatically  generated by the devicetree: https://github.com/nrfconnect/sdk-zephyr/blob/fcaa60a99fa9d5256078ed28557856ec3709cfa9/soc/arm/nordic_nrf/Kconfig.peripherals#L206-L207

I suggest that you start by checking on your SPU node in the custom board DTS files.

Tip: To check the built DTS-files, you can have a look at build/zephyr/zephyr.dts

Regards,
Sigurd Hellesvik

[frax84]

The board name is "nrf5340dk_nrf5340_cpuapp_ns". You can find attached the build/zephyr/zephyr.dts file of the build (Tollchain/SDK 2.3.0) for this board. I just rebuilt to be sure i was not hallucinating, so i can confirm it's the right file

7206.zephyr.dts

[Sigurd Hellesvik]

frax84 said:

nrf5340dk_nrf5340_cpuapp_ns

That is for the TF-M build of the board.

When first testing for a custom board, I recommend that you start with nrf5340dk_nrf5340_cpuapp and then go to the TF-M version after non-TF-M works.

Reason that build file does not have the SPU, is that TF-M is controlling the SPU instead of the application.

[frax84]

Ok, i think i got the point. As you foresaw, building cpuapp and not cpuapp_ns works.

Thank you

[Sigurd Hellesvik]

You likely want to add TF-M after, so do not hesitate to do that.

I just advocate that you make it work without first.
This is also a good hint to where the error happens, and that it is probably related to adding TF-M.

Let me know if you got any more questions

[frax84]

Hi Sigurd,

This message just to highlight that I verified your answer but in my tickets list the post still is on "Waiting".