In the Vitis Classic flows, the platform was generated automatically when the XSA was input by the user. However, for Vitis Unified IDE, the user will need to manually create it. This is by design, to allow for a clean workspace. In the embedded flow, the platform will contain the SDT. Any domains, and/or boot components will be placed in the platform.
From the Welcome Screen, users can select the Create Platform Component under Embedded Development. Or from the File menu, under New Component, Platform.
Before we proceed, let’s discuss what we actually need to both boot and deploy our user application on the development board.
For example, let’s take the Zynq UltraScale. This device consists of a Processor Subsystem Unit (PSU) and Programmable Logic (PL). When users exported the hardware in Vivado, this created an XSA file. This XSA file is a container file that contains (amongst other files) the PSU config files; psu_init.c and .h files that are generated when you generate the Output Products in Vivado. These files are used by the First Stage BootLoader (FSBL) to config the PSU. There may also a bitstream (if included when exporting the hardware), this is used to config the PL. There is also the metadata about our block design, IP enabled in the PSU, IP in the PL and how each of these IP are configured called cell properties. This metadata can be extracted by the Vitis Unified tool to tailor a software system that is based on the hardware created in Vivado. In summary, to boot (either in JTAG, SD card or otherwise) we need to program the PSU. The PSU is programmed via the FSBL. If the PL needs to be programmed (optional), this is done via the bitstream. In the Vitis Unified tool, users can create these files by using the Create Platform Component.
For Versal, the Platform Loader Manager (PLM) is created in Vivado and is packaged into a Programmable Definition Image (PDI) in Vivado and this PDI is added to the XSA file. So, users do not need to build boot artifacts in the Vitis IDE
Users have two options: create a new platform using the XSA exported from Vivado or use an existing platform. We will create a new platform from an existing XSA.
The SDT (System Device Tree) is a new concept in Vitis Unified flow. Previously, in Vitis Classic the hardware metadata was extracted directly from the XSA using HSI API in an “AD Hoc” manner when needed by the Vitis tools; such as extracting processors for platform creation or extracting IP for BSP creation. In Vitis unified flow, the tools will create a SDT (System Device Tree) when users generate the platform, and this is used to provide the hardware metadata to Vitis via the lopper utility.
Users will now be presented with a drop down box to select the operating system and the processor will be auto-populated from the SDT. Tick the Generate boot artifacts box and proceed
Users will now be presented with the view below. The explorer view is on the top left, the flow view is the bottom left. The platform is not built by default, users can do this by select the build icon in the flow view. This will build the platform, which consists of our domains. The platform will begin building in the background and we can move on to Create Application.
