SPRUIL1D May 2019 – December 2024 DRA829J , DRA829J-Q1 , DRA829V , DRA829V-Q1 , TDA4VM , TDA4VM-Q1
The PCIe Core module supports dual mode of operation - it can be configured as an End Point (EP) and also as a Root Port (RP). The operational mode is selected with PCIе_MODE_SELECT bit. Typically, it is expected that these bits be driven from a SoC level register that is programmed during initial power up based on settings in the SoC boot configuration or a non-volatile storage such as eFuse or Flash memory. The table below lists the encodings available.
It is not expected that pcie_mode_select would have to change during a full power cycle of the device. It is more likely that the operational mode of a SoC will stay as EP or RP for a particular end product’s life cycle. The chip level circuitry is expected to provide the hardware input to set RP or EP mode and not switch back during operation and forth without a reset cycle.
The PCIe core module supports four virtual channels (VC) and four transfer classes (TC). The VCs can be used to implement Quality-of-Service (QoS) mechanism by enabling priority or round-robin arbitration. Typically, the highest numbered enabled VC is assigned the highest priority.
The PCIe core module is configured to support Single Root I/O virtualization (SR-IOV). It supports 6 Physical Functions (PF) and 16 Virtual Functions (VF).
There are two AXI4.0 master ports and two AXI4.0 slave port in the PCIe core. The two AXI master and slave ports are labeled high-priorty and low-priority. Ingress data traffic that is assigned the highest priority (highest VC) will be delivered on the high-priority AXI master port. Data on the other VCs will be delivered on the low priority AXI master port. Similarly, egress data that is presented on the high-priority slave port will be assigned the highest VC by the PCIe core. Data presented on the low priority AXI slave port will be assigned lower VCs. This will enable the system to transfer the high and low priority data streams to different destinations based on the latency requirements. Having the two AXI master ports will also prevent low priority traffic from blocking the high priority traffic.