From: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx> Add documentation on identifying FPGA based PCI cards prompted by discussion on the linux-fpga@xxxxxxxxxxxxxxx mailing list. Signed-off-by: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx> --- v3: Add url to page tracking PCI ID information for DFL based cards. v2: Introduced in v2. --- Documentation/fpga/dfl.rst | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/Documentation/fpga/dfl.rst b/Documentation/fpga/dfl.rst index 15b670926084..5144775b860a 100644 --- a/Documentation/fpga/dfl.rst +++ b/Documentation/fpga/dfl.rst @@ -507,6 +507,27 @@ ids application. https://github.com/OPAE/dfl-feature-id +PCI Device Identification +================================ +Since FPGA based PCI cards can be reconfigured to a perform a completely +new function at runtime, properly identifying such cards and binding the +correct driver can be challenging. In many use cases, deployed FPGA based +PCI cards are essentially static and the PCI Product ID and Vendor ID pair +is sufficient to identify the card. The DFL framework helps with the +dynamic case of deployed FPGA cards changing at run time by providing +more detailed information about card discoverable at runtime. + +At one level, the DFL on a PCI card describes the function of the card. +However, the same DFL could be instantiated on different physical cards. +Conversely, different DFLs could be instantiated on the same physical card. +Practical management of a cloud containing a heterogeneous set of such cards +requires a PCI level of card identification. While the PCI Product ID and +Vendor ID may be sufficient to bind the dfl-pci driver, it is expected +that FPGA PCI cards would advertise suitable Subsystem ID and Subsystem +Vendor ID values. Further PCI Product, Vendor, and Subsystem id tracking +can be found at https://github.com/OPAE/dfl-feature-id/blob/main/dfl-pci-ids.rst. + + Location of DFLs on a PCI Device ================================ The original method for finding a DFL on a PCI device assumed the start of the -- 2.25.1
