RFC: Add support for Beken BK7258 Cortex-M33 SoC

[Embracecactus]

RFC: Add support for Beken BK7258 Cortex-M33 SoC

Hello Zephyr maintainers and community,

I would like to propose adding support for the Beken BK7258 Cortex-M33 SoC to Zephyr and would appreciate feedback before starting the upstream work.

This is a community-driven port and is not an official vendor contribution.

Initial Scope

To keep the first contribution small and easy to review, I plan to implement only the basic platform support:

• BK7258 Cortex-M33 SoC support
• One development board
• UART console
• GPIO
• Pin control (pinctrl)
• Device tree support
• hello_world
• blinky

Additional peripherals (Wi-Fi, Bluetooth, USB, camera, etc.) are not part of the initial contribution.

Boot Flow

The BK7258 contains a vendor BootROM which is responsible for loading and validating a custom bootloader.

The proposed boot sequence is:

BootROM
↓
Custom Bootloader
↓
Zephyr Application

The BootROM is provided by the vendor and will not be modified.

The custom bootloader performs only the minimal initialization required before jumping to the Zephyr application. The bootloader itself is not intended to become part of the Zephyr project.

Development Plan

I plan to submit the support incrementally to make review easier, for example:

1. Vendor prefix and SoC skeleton
2. DeviceTree and board support
3. UART console
4. GPIO and pinctrl
5. Documentation and additional cleanup

Questions

Before I begin preparing the upstream patches, I would appreciate guidance on the following:

1. Does this overall approach align with Zephyr’s expectations for adding a new SoC?
2. Is the proposed boot flow acceptable from the project’s perspective?
3. Are there any recommendations regarding the directory structure or patch organization?
4. Would maintainers prefer an early Draft PR after the basic SoC and board skeleton are ready?

Any suggestions or recommendations would be greatly appreciated.

Thank you!