Xilinx QDMA Linux DriverΒΆ

Xilinx QDMA Subsystem for PCIe example design is implemented on a Xilinx FPGA, which is connected to an X86 host system through PCI Express. Xilinx QDMA Linux Driver package consists of user space applications and kernel driver components to control and configure the QDMA subsystem.

QDMA Linux Driver consists of the following four major components:

  • QDMA HW Access: QDMA HW Access module handles all the QDMA IP register access functionality and exposes a set of APIs for register read/writes.

  • Libqdma: Libqdma module exposes a set of APIs for QDMA IP configuration and management. It uses the QDMA HW Access layer for interacting with the QDMA HW and facilitates the upper layers to achieve the following QDMA functionalities

    • Physical Function(PF) Management
    • Virtual Function(VF) Management
    • Communication Management between PF and VF
    • QDMA Queue Configuration and Control
    • Descriptor Rings Creation and Control
    • Transfer Management
    • DebugFS Support

  • Driver Interface: This layer create a simple linux pci_driver ( struct pci_driver ) interface and a character driver interface ( struct file_operations ) to demonstrate the QDMA IP functionalities using the Linux QDMA IP driver. It creates a netlink ( NL ) interface to facilitate the user applications to interact with the Libqdma module. It also creates sysfs interface to enable users to configure and control various QDMA IP parameters.

  • Applications: QDMA IP Driver provides the following sample applications.

    • dma-ctl : This application provides set of commands to configure and control the queues in the system
    • dma-to-device : This application enables the users to perform Host to Card (H2C) transfer
    • dma-from-device : This application enables the users to perform Card to Host (C2H) transfer
    • dma-perf : This application provides commands to measure performance numbers for QDMA IP in MM and ST modes
    • dma-latency: This application enables the user to measure ping pong latency for ST H2C/C2H transfers
    • dma-xfer: This is a simple application to demonstrate the QDMA transfers
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