ETHSW internal peripheral

Applicable for

1. Article purpose[edit | edit source]

The purpose of this article is to:

briefly introduce the ETHSW peripheral and its main features,
indicate the peripheral instances assignment at boot time and their assignment at runtime (including whether instances can be allocated to secure contexts),
list the software frameworks and drivers managing the peripheral,
explain how to configure the peripheral.

2. Peripheral overview[edit | edit source]

The ETHSW peripheral is based on Edge IP solution from TTTech Industrial, which offers highly configurable TSN functionality for industrial devices. Edge IP Solution includes IP core and associated software stacks for fast and easy integration.

The Edge IP Solution includes configurable building blocks:

NETCONF/YANG (IEEE 802.1Qcc : SRP Enhancements)

LLDP (Link Layer Discovery Protocol)

MSTP (Multiple Spanning Tree Protocol)

gPTP (generic Precision Time Protocol)

IEEE 802.1AS : Time Synchronization

IEEE 802.1Qbv : Time Aware Shaping

IEEE 802.1Qbu : Frame Preemption

IEEE 802.3br : Interspersing express traffic

IEEE 802.1Qci : Seamless Redundancy

IEEE 802.1CB : Seamless Redundancy

Refer to the STM32 MPU reference manuals for the complete list of features, and to the software frameworks and drivers, introduced below, to see which features are implemented.

3. Peripheral usage[edit | edit source]

This chapter is applicable in the scope of the OpenSTLinux BSP running on the Arm^® Cortex^®-A processor(s), and the STM32CubeMPU Package running on the Arm^® Cortex^®-M processor.

3.1. Boot time assignment[edit | edit source]

3.1.1. On STM32MP2 series[edit | edit source]

Click on to expand or collapse the legend...

Check boxes illustrate the possible peripheral allocations supported by OpenSTLinux BSP:

⬚ means that the peripheral can be assigned to the given boot time context, but this configuration is not supported in OpenSTLinux BSP.
☐ means that the peripheral can be assigned to the given boot time context.
☑ means that the peripheral is assigned by default to the given boot time context and that the peripheral is mandatory for the OpenSTLinux BSP.
✓ is used for system peripherals that cannot be unchecked because they are hardware connected in the device.

The present chapter describes STMicroelectronics recommendations or choice of implementation. Additional possibilities might be described in STM32 MPU reference manuals.

Domain	Peripheral	Boot time allocation				Comment
Domain	Peripheral	Instance	Cortex-A35 secure (ROM code)	Cortex-A35 secure (TF-A BL2)	Cortex-A35 nonsecure (U-Boot)	Comment
Networking	ETHSW	ETHSW			⬚

3.2. Runtime assignment[edit | edit source]

3.2.1. On STM32MP25x lines [edit | edit source]

Click on to expand or collapse the legend...

STM32MP25 internal peripherals

Check boxes illustrate the possible peripheral allocations supported by OpenSTLinux BSP:

⬚ means that the peripheral can be assigned to the given runtime context, but this configuration is not supported in OpenSTLinux BSP.
☐ means that the peripheral can be assigned to the given runtime context.
☑ means that the peripheral is assigned by default to the given runtime context and that the peripheral is mandatory for the OpenSTLinux BSP.
✓ is used for system peripherals that cannot be unchecked because they are hardware connected in the device.

Refer to How to assign an internal peripheral to an execution context for more information on how to assign peripherals manually or via STM32CubeMX.
The present chapter describes STMicroelectronics recommendations or choice of implementation. Additional possibilities might be described in STM32MP25 reference manuals.

Domain	Peripheral	Runtime allocation						Comment
Domain	Peripheral	Instance	Cortex-A35 secure (OP-TEE / TF-A BL31)	Cortex-A35 nonsecure (Linux)	Cortex-M33 secure (TF-M)	Cortex-M33 nonsecure (STM32Cube)	Cortex-M0+ (STM32Cube)	Comment
Networking	ETHSW	ETHSW	⬚^OP-TEE	☐	⬚	⬚

4. Software frameworks and drivers[edit | edit source]

Below are listed the software frameworks and drivers managing the ETHSW peripheral for the embedded software components listed in the above tables.

Linux^®: Ethernet switch overview

5. How to assign and configure the peripheral[edit | edit source]

The peripheral assignment can be done via the STM32CubeMX graphical tool (and manually completed if needed).
This tool also helps to configure the peripheral by generating:

partial device trees (pin control and clock tree) for the OpenSTLinux software components,
HAL initialization code for the STM32CubeMPU Package.

The configuration is applied by the firmware running in the context in which the peripheral is assigned.

When the Ethernet switch is assigned to the Linux^® OS, it is configured through the device tree according to the information given in the Ethernet switch device tree configuration article.