Custom PCIe x1 DMA Interposer Card Development -- 2

Hardware Description – DMA Interposer Card Overview The DMA Interposer Card is a custom PCIe x1 device designed to interface between a host computer and a downstream PCIe endpoint (e.g., a Wi-Fi adapter). The card provides transparent passthrough of the endpoint device to the host system, while embedding an FPGA-based DMA engine capable of bus mastering, memory injection, and packet manipulation. Control of the DMA engine is performed via the PCILeech software suite, enabling flexible direct memory access operations. Functional Blocks 1. PCIe Passthrough Bridge • Provides a transparent PCIe x1 interconnect between the host computer and the attached endpoint device. • Maintains compliance with the PCIe protocol to ensure the endpoint is enumerated by the host as if connected directly. 2. FPGA Subsystem (AMD/Xilinx FPGA) • Implements custom PCIe cores for bus mastering and DMA transfers. • Supports injection of crafted TLPs (Transaction Layer Packets) into the PCIe bus. • Allows monitoring, filtering, and modification of traffic between host and endpoint device. • Exposes a control interface for PCILeech over a reserved PCIe BAR region. 3. DMA Engine • Capable of arbitrary read/write operations into host memory space. • Implements scatter-gather and burst transfers for high throughput. • Supports both synchronous (command-driven) and autonomous (scripted FPGA logic) operations. 4. Control & Debug Interface • Host computer loads PCILeech driver/software to detect and operate the DMA engine. • Control commands are mapped to FPGA registers accessible via PCIe BAR. • Optional UART/JTAG debug headers for FPGA reconfiguration and development. 5. Power & Form Factor • Standard PCIe x1 form factor, powered directly from the slot (3.3V/12V). • Optional external power connector for high-power endpoints.