1. Article purpose[edit source]
The purpose of this article is to:
- briefly introduce the TZC peripheral and its main features
- indicate the level of security supported by this hardware block
- explain how it can be allocated to the three runtime contexts and linked to the corresponding software components
- explain, when necessary, how to configure the TZC peripheral.
2. Peripheral overview[edit source]
The TZC peripheral is used to filter read/write accesses to the DDR controller according to TrustZone access rights, and according to Non-Secure master Address ID (NSAID) on up to 9 programmable regions.
2.1. Features[edit source]
Refer to the STM32MP15 reference manuals for the complete list of features, and to the software components, introduced below, to see which features are implemented.
2.2. Security support[edit source]
The TZC is a secure peripheral.
3. Peripheral usage and associated software[edit source]
3.1. Boot time[edit source]
The TZC is configured at boot time to setup DDR accesses.
3.2. Runtime[edit source]
3.2.1. Overview[edit source]
The TZC is a system peripheral and is controlled by the Arm® Cortex®-A7 secure.
3.2.2. Software frameworks[edit source]
| Domain | Peripheral | Software frameworks | Comment | ||
|---|---|---|---|---|---|
| Cortex-A7 secure (OP-TEE) |
Cortex-A7 non-secure (Linux) |
Cortex-M4 (STM32Cube) | |||
| Security | TZC | OP-TEE TZC driver | |||
3.2.3. Peripheral configuration[edit source]
The configuration is applied by the firmware running in the secure context.
This configuration is done in TF-A or in OP-TEE.
3.2.4. Peripheral assignment[edit source]
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.
- ✓ is used for system peripherals that cannot be unchecked because they are statically connected in the device.
Refer to How to assign an internal peripheral to a runtime 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) | |||
| Security | TZC | TZC | ✓ | |||
4. How to go further[edit source]
The TZC is an Arm® peripheral: TZC-400 TrustZone Address Space Controller[1]
5. References[edit source]