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The DT nodes provide access to the boot interfaces and properties. The DT provides a data structure that describes the system’s hardware information. The image execution environment, which includes firmware such as XBL and UEFI, reads this information. You can modify the DT properties associated with boot to customize the functionality of various device software features. For information about modifying the interfaces using the QDTE tool and changing the DT properties in the prebuilt Devicetree blob (DTB) using the QDTE tool, see Configure QDTE. For more information about DT, see https://github.com/devicetree-org.

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XBL configuration and UEFI DTB files

xbl_config.elf carries the XBL configuration DT nodes on every platform. Whether it also carries the UEFI DT nodes, or whether those nodes live in a separate UEFI DTB file, depends on the platform.

Table: XBL configuration and UEFI DTB files by platform

For Shikra and IQ10/Nord, xbl_config.elf contains only XBL-specific DT nodes, while UEFI-specific DT nodes are in the separate uefi_dtbs.elf (or uefi_dtbs_kvm.elf) file. The boot flow depends on which file is flashed: flashing uefi_dtbs.elf results in Gunyah-based boot, and flashing uefi_dtbs_kvm.elf results in KVM-based boot.For Hamoa/IQ-X7181 and Purwa/IQ-X5121, xbl_config.elf contains only XBL-specific DT nodes, while UEFI-specific DT nodes are in the separate, compressed uefi_dtbs.xz (or uefi_dtbs_kvm.xz) file — only the compressed .xz file is used on these platforms. The boot flow depends on which file is flashed: flashing uefi_dtbs.xz results in Gunyah-based boot, and flashing uefi_dtbs_kvm.xz results in KVM-based boot.For QCS6490/Kodiak/RB3Gen2, QCS5430/Kodiak/RB3Gen2Lite, IQ9/IQ-9075/Lemans, IQ8/IQ-8275/Monaco, and IQ6/IQ615/Talos, xbl_config.elf contains DT nodes for both XBL and UEFI. The boot flow depends on which file is flashed: flashing xbl_config.elf results in Gunyah-based boot, and flashing xbl_config_kvm.elf results in KVM-based boot.
Platform information The platform information devicetree provides the information about CDT, which contains platform information version, platform type, major hardware version, minor hardware version, subtype and OEM-id. Boot devicetree properties The boot devicetree properties provide information on how to enable and disable user-initiated emergency download (EDL) in XBL. The boot DT properties also describe the EDL timeout and the USB cable options that can force the system into the EDL mode. The boot-related functionality configures using the boot DT properties. Power management integrated circuit (PMIC) The power management integrated circuit (PMIC) is a specialized electronic component that manages various power supply requirements within a device. General-purpose input/output (GPIO) functions The hardware controls the multiplexing of general-purpose input/output (GPIO) and alternate functions through the top-level mode multiplexer (TLMM). You can configure the GPIOs during the boot process using the DT properties for TLMM. Buses A bus facilitates data transfer among various system components. The DT properties allow for the configuration of the Qualcomm Universal Peripheral (QUP) v3 serial interface device nodes. Storage The DT properties for storage configurations. USB The DT properties for USB allow you to adjust the USB signal quality.

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Next steps

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