CRYP device tree configuration






1 Article purpose[edit]

The purpose of this article is to explain how to configure the CRYP[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 CRYP[1], used by STM32 CRYP Linux driver.

2 DT bindings documentation[edit]

The CRYP [1] is represented by the STM32 CRYP device tree bindings[3].

3 DT configuration[edit]

This hardware description is a combination of STM32 microprocessor and board device tree files. See Device tree for explanations on device tree file split.

The 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]

The CRYP node is declared in stm32mp157c.dtsi[4]. It provides the hardware registers base address, clock, interrupt and reset.

cryp1: cryp@54001000 {
	compatible = "st,stm32mp1-cryp";
	reg = <0x54001000 0x400>;
	interrupts = <GIC_SPI 79 IRQ_TYPE_LEVEL_HIGH>;
	clocks = <&rcc CRYP1>;
	resets = <&rcc CRYP1_R>;
	status = "disabled";
};
Warning.png This device tree part is related to STM32 microprocessors. It should be kept as is, without being modified by the end-user.

3.2 DT configuration (board level)[edit]

This part is used to enable the CRYP used on a board. This is done by setting the status property to okay.

3.3 DT configuration examples[edit]

&cryp1 {
	status = "okay";
};

4 How to configure the DT using STM32CubeMX[edit]

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]

Please refer to the following links for additional information:

Cryptographic processor

Operating System

Device Tree

Generic Interrupt Controller

Serial Peripheral Interface

Attachments

Discussions