1. Article purpose[edit source]
The purpose of this article is to explain how to configure the CRC[1] when the peripheral is assigned to Linux® OS.
The configuration is performed using the device tree mechanism[2].
The Device tree provides a hardware description of the CRC[1], used by STM32 CRC Linux driver.
If the peripheral is assigned to another execution context, refer to How to assign an internal peripheral to a runtime context article for guidelines on peripheral assignment and configuration.
2. DT bindings documentation[edit source]
The device tree binding documents are stored either in the given applicable components listed below, or in the Linux kernel repository:
- Linux® OS :
- CRC device tree bindings: Documentation/devicetree/bindings/crypto/st,stm32-crc.yaml
3. DT configuration[edit source]
This hardware description is a combination of the STM32 microprocessor device tree files (.dtsi extension) and board device tree files (.dts extension). See the Device tree for an explanation of the device-tree file organization.
STM32CubeMX can be used to generate the board device tree. Refer to How to configure the DT using STM32CubeMX for more details.
3.1. DT configuration (STM32 level)[edit source]
The CRC node is declared in stm32mp151.dtsi[3]. It provides the hardware registers base address and the clock.
crc1: crc@58009000 {
compatible = "st,stm32f7-crc";
reg = <0x58009000 0x400>;
clocks = <&rcc CRC1>;
status = "disabled";
};
3.2. DT configuration (board level)[edit source]
This part is used to enable the CRC used on a board. This is done by setting the status property to okay.
3.3. DT configuration examples[edit source]
&crc1 {
status = "okay";
};
4. How to configure the DT using STM32CubeMX[edit source]
The STM32CubeMX tool can be used to configure the STM32MPU device and get the corresponding platform configuration device tree files.
The STM32CubeMX may not support all the properties described in the above DT bindings documentation paragraph. If so, the tool inserts user sections in the generated device tree. These sections can then be edited to add some properties and they are preserved from one generation to another. Refer to STM32CubeMX user manual for further information.
5. References[edit source]
Please refer to the following links for additional information: