Implementing Beaglebone Black to Zephyr 4.1(DTS: Persistent 'unexpected length' & 'empty_file.c' context loss when porting AM335x (BeagleBone Black))

[Requasar]

Origin

https://docs.zephyrproject.org/latest/releases/release-notes-4.1.html
https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm/boot/dts?h=am6-abi-ti-linux-4.19.y

Purpose

Add initial board support for the BeagleBone Black (Rev C) based on the TI AM335x SoC. The goal is to get a minimal "hello_world" sample to build and run.

Mode of Integration

This is not an integration request. I am seeking community support for a blocking DTS issue for a personal project.

Maintainership

Seeking community guidance to resolve a blocking DTS issue first. A maintainer can be assigned once the port is functional.

Pull Request

No response

Description

PROBLEM DESCRIPTION

I am trying to get the BeagleBone Black (Rev C) board running with Zephyr v4.1.0 for a personal project.

After extensive debugging, I am consistently blocked by a persistent DTS parsing error. My analysis suggests this is a "context loss" issue within the build system, where the parser fails to correctly process node properties.

The consistent, blocking error is:

devicetree error: unexpected 'interrupt-cells:' length in binding for <Node /ocp/interrupt-controller@48200000 in 'zephyr/misc/empty_file.c'> - 0 instead of 1

The reference to empty_file.c is the key symptom. This happens even when all definitions are placed within a single, self-contained DTS file, ruling out simple #include or pathing issues.

---

REPRODUCIBLE REPOSITORY & RELEVANT FILES

To make debugging as easy as possible, I have created a dedicated GitHub repository containing all the necessary files in their correct Zephyr directory structure.

>> REPOSITORY LINK: https://github.com/Requasar/Beaglebone_black_Zephyr <<

---

MY ANALYSIS OF THE CORE PROBLEM

My analysis points to a direct contradiction concerning the interrupt-controller node.

The error message claims #interrupt-cells is 0, but my source files explicitly define it as 1.

1. In my DTS file (.../dts/arm/ti/am33xx.dtsi in the repo):

   intc: interrupt-controller@48200000 {
       compatible = "ti,am33xx-intc";
       interrupt-controller;
       #interrupt-cells = <1>; // <-- Explicitly set to 1
       reg = <0x48200000 0x1000>;
   };

2. In my YAML binding file (.../dts/bindings/interrupt-controller/ti,am33xx-intc.yaml in the repo): To be certain, I enforced this rule with const: 1, but it had no effect on the error.

   '#interrupt-cells':
     type: int
     const: 1
     required: true

This demonstrates that even though the source files are correct, the build system's parser is failing to read the value correctly.

---

MY REQUEST

I am simply trying to get it working and am hoping for some guidance from the community. I have reached the limit of my debugging abilities.

I would be extremely grateful for any help on:

• Is this a known issue or bug with the AM335x SoC on Zephyr 4.1.0?
• Is there a fundamental flaw in my file structure or DTS approach in the linked repository that I am missing?
• What could cause this specific empty_file.c context-loss error?
• My biggest concern is, my .dts .dtsi files are from Texas Instruments:
  https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm/boot/dts?h=am6-abi-ti-linux-4.19.y

and i thought my .dtsi files are not compatible with zephyr because i didn't create them directly for zephyr and it can create issues but i am not sure about it. Should i expect those files to work zephyr with few changes?

Thank you for your time and assistance.

---

FULL ERROR LOG & ENVIRONMENT

• OS: Ubuntu 24.04
• Zephyr Version: 4.1.0 (Note: The log shows a newer version, but my primary target is 4.1.0)
• Zephyr SDK Version: 0.17.2
• Build Command: west build -b beaglebone_black samples/hello_world

-- west build: generating a build system
Loading Zephyr default modules (Zephyr base).
-- Application: /home/zephyrproject-main/zephyr/samples/hello_world
-- CMake version: 3.29.3
-- Found Python3: /home/zephyr-env-main/bin/python3 (found suitable version "3.12.3", minimum required is "3.12.1") found components: Interpreter
-- Cache files will be written to: /home/.cache/zephyr
-- Zephyr version: 4.2.00-rc1 (/home/zephyrproject-main/zephyr)
-- Found west (found suitable version "1.4.0", minimum required is "0.14.0")
-- DEBUG: Wanted BOARD: beaglebone_black
-- DEBUG: Error Message (err_board): 
-- DEBUG: Used SoC (ZEPHYR_SOC_NAME): 
-- Board: beaglebone_black, qualifiers: am335x
-- Found host-tools: zephyr 0.17.2 (/home/zephyr-sdk-0.17.2)
-- Found toolchain: zephyr 0.17.2 (/home/zephyr-sdk-0.17.2)
-- Found Dtc: /home/zephyr-sdk-0.17.2/sysroots/x86_64-pokysdk-linux/usr/bin/dtc (found suitable version "1.7.0", minimum required is "1.4.6")
-- Found BOARD.dts: /home/zephyrproject-main/zephyr/boards/arm/beaglebone_black/beaglebone_black.dts
devicetree error: unexpected 'interrupt-cells:' length in binding for <Node /ocp/interrupt-controller@48200000 in 'zephyr/misc/empty_file.c'> - 0 instead of 1
CMake Error at /home/zephyrproject-main/zephyr/cmake/modules/dts.cmake:306 (execute_process):
  execute_process failed command indexes:

    1: "Child return code: 1"

Call Stack (most recent call first):
  /home/zephyrproject-main/zephyr/cmake/modules/zephyr_default.cmake:131 (include)
  /home/zephyrproject-main/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:66 (include)
  /home/zephyrproject-main/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:92 (include_boilerplate)
  CMakeLists.txt:5 (find_package)


-- Configuring incomplete, errors occurred!
FATAL ERROR: command exited with status 1: /home/.local/bin/cmake -DWEST_PYTHON=/home/zephyr-env-main/bin/python3 -B/home/zephyrproject-main/zephyr/build -GNinja -DBOARD=beaglebone_black -S/home/zephyrproject-main/zephyr/samples/hello_world

### Security

_No response_

### Dependencies

_No response_

### Version or SHA

2ccf05b158798b274579b1621b16c940ba186452

### License (SPDX)

Apache-2.0

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