ETH internal peripheral

Applicable for STM32MP13x lines, STM32MP15x lines

1 Article purpose[edit]

The purpose of this article is to:

  • briefly introduce the ETH 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]

The ETH peripheral is based on Synopsys DesignWare® Ethernet GMAC IP, which enables the host to communicate data using the Gigabit Ethernet protocol (IEEE 802.3) at 10, 100 and 1000 Mbps.
The peripheral is composed of three main layers: the gigabit ethernet media access controller (GMAC), the MAC transaction layer (MTL), and the MAC DMA controller (MDC). The driver used to drive the ETH is Stmmac.

The Ethernet peripheral main features are the following:

  • Compliance with IEEE 802.3 specifications
  • Support for IEEE 1588-2002 and IEEE 1588-2008 standards for precision networked clock synchronization
IEEE 802.3-az for Energy Efficient Ethernet (EEE)
IEEE 802.3x flow control automatic transmission of zero-quanta pause frame on flow control input de-assertion.
IEEE 802.1Q VLAN tag detection for reception frames on STM32MP15x lines More info.png only
AMBA 2.0 for AHB Master/Slave ports and AMBA 3.0 for AXI Master/Slave ports
  • Configurability allowing to support data transfer rates of 10/100/100 Mbps, 10/100 Mbps only or 1000 Mbps only
  • Support for multiple TCP/IP offload functions

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]

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]

3.1.1 On STM32MP1 series[edit]

The Ethernet peripheral can be used at boot time by SSBL (by UBoot with tftp protocol for image loading). See How to boot the kernel via TFTP from U-Boot for more details.

Click on the right to expand the legend...

Check boxes illustrate the possible peripheral allocations supported by STM32 MPU Embedded Software:

  • 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 STM32 MPU Embedded Software distribution.
  • means that the peripheral can be assigned to the given boot time context, but this configuration is not supported in STM32 MPU Embedded Software distribution.
  • 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
Instance Cortex-A7
secure
(ROM code)
Cortex-A7
secure
(TF-A BL2)
Cortex-A7
non-secure
(U-Boot)
Networking ETH Any instance Assignment (single choice)

3.2 Runtime assignment[edit]

3.2.1 On STM32MP13x lines More info.png[edit]

Click on the right to expand the legend...

STM32MP13 internal peripherals

Check boxes illustrate the possible peripheral allocations supported by STM32 MPU Embedded Software:

  • 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 STM32 MPU Embedded Software distribution.
  • means that the peripheral can be assigned to the given runtime context, but this configuration is not supported in STM32 MPU Embedded Software distribution.
  • 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 STM32MP13 reference manuals.

Domain Peripheral Runtime allocation Comment
Instance Cortex-A7
secure
(OP-TEE)
Cortex-A7
non-secure
(Linux)
Networking ETH ETH1 Assignment (single choice)
ETH2 Assignment (single choice)

3.2.2 On STM32MP15x lines More info.png[edit]

Click on the right to expand the legend...

STM32MP15 internal peripherals

Check boxes illustrate the possible peripheral allocations supported by STM32 MPU Embedded Software:

  • 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 STM32 MPU Embedded Software distribution.
  • means that the peripheral can be assigned to the given runtime context, but this configuration is not supported in STM32 MPU Embedded Software distribution.
  • 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 possiblities might be described in STM32MP15 reference manuals.

Domain Peripheral Runtime allocation Comment
Instance Cortex-A7
secure
(OP-TEE)
Cortex-A7
non-secure
(Linux)
Cortex-M4

(STM32Cube)
Networking ETH ETH Assignment (single choice)

4 Software frameworks and drivers[edit]

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

5 How to assign and configure the peripheral[edit]

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

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

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

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