Device tree describes the hardware components of the system. AMD device tree generator (DTG) can generate the device tree according to hardware configurations from an XSA file. You needs to add customization settings in system-user.dtsi for PetaLinux to consume. For example, unavailable settings in XSA, any driver nodes that don’t have a corresponding hardware, or customising settings if the user needs to override any DTG auto-generated configurations.
ZOCL driver module has no associated hardware, but it is required by XRT and Vitis acceleration flow. It requires a device tree node to describe the interrupt signal relationship. In previous Vitis and PetaLinux versions, you had to add ZOCL device tree node manually. From 2021.1, PetaLinux can add ZOCL device tree node automatically if the XSA is a Vitis extensible platform project.
Device Tree Generator (DTG) also overrides the interrupt controller (axi_intc_0) input numbers parameter from 0 to 32 because in the platform XSA the interrupt controller inputs have not been connected but they will be connected after v++ links the acceleration kernels.
You can review the PetaLinux generated device tree in project-spec/components/device-tree/device-tree/pl.dtsi file.
You can also add your custom device tree modifications to project-spec/meta-user/recipes-bsp/device-tree/files/system-user.dtsi. For example this is how you setup sdhci1 to low speed mode.
&sdhci1 {
no-1-8-v;
disable-wp;
};
sdhci1 node decreases SD Card speed for better card compatibility on ZCU104 board. This only relates to ZCU104 and is not a part of Vitis acceleration platform requirements.
Note: an example file zcu104/system-user.dtsi is provided for zcu104 board and vck190/system-user.dtsi for VCK190 board.