SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
The PCIe controller to L3_MAIN connectivity is illustrated, on the left-hand side of the Figure 24-161. Read/write accesses from external PCIe components to the device local system memory on L3_MAIN are performed through the PCIe_SS master (initiator) port - PCIe_SS_INIT. The addresses issued on this port are by default directly routed to the L3_MAIN, but they can be optionally routed to and further translated by the device memory management unit - MMU2 before they reach the L3_MAIN target. For more details on MMU port, refer to Section 24.9.4.3.1.1.
On the other hand, the device local hosts (MPU, DSP, and so forth) initiate accesses to the PCIe controller local registers and PCIe bus remote devices via a PCIe_SS slave (target) port - PCIe_SS_TARG on the L3_MAIN. No MMU is included on the slave path. The slave interface has two uses: manage the local PCIe controller, and carry outbound PCIe traffic, that is initiated locally by PCIe hosts (MPU, DSP, DMAs, and so forth) within the device.