Hello, Xilinx Alveo PCIe accelerator cards use flattened device tree to describe HW subsystems or endpoints. Each device tree node represents a hardware endpoint and each endpoint is an hardware unit which requires a driver. The product detail: https://www.xilinx.com/products/boards-and-kits/alveo.html The feedback from the previous patches was to create a base tree if there is not one and apply the unflattened device nodes by existing Linux platform device and OF infrastructure. Please refer to previous discussion with device tree and fpga maintainers. https://lore.kernel.org/lkml/CAL_JsqJfyRymB=VxLuQqLpep+Q1Eie48dobv9sC5OizDz0d2DQ@xxxxxxxxxxxxxx/ https://lore.kernel.org/lkml/20220105225013.1567871-1-lizhi.hou@xxxxxxxxxx/ This patch adds OF_EMPTY_ROOT config. When it is selected and there is not a device tree, create an empty device tree root node. Lizhi Hou (1): of: create empty of root drivers/of/Kconfig | 3 +++ drivers/of/Makefile | 1 + drivers/of/of_empty_root.c | 51 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 55 insertions(+) create mode 100644 drivers/of/of_empty_root.c -- 2.27.0