Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 4/01/2024
Public

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4.3.4.2. DTI Interconnect Topology

The Arm* MMU-600 introduces a new interconnect specification to enable communication between the TBU instances and the TCU. This protocol runs on top of AXI4-Stream interfaces, so each DTI port has both upstream and downstream AXI4-Stream ports. The MMU-600 provides three DTI components to use to create the topology that the implementation requires. These components are the Switch, Sizer, and Register Slice.

The SMMU in Agilex™ 5 contains two instances of the DTI Switch to aggregate the traffic from the six TBUs into a single DTI interface that connects to the TCU. One of these switches resides in the PSS and connects to the four TBU (DMA, IO, SDM, and TSN) instances that are in the PSS. The other switch resides in the APS and connects to the two TBUs connected to the FPGA fabric and the output of the switch in the PSS. The output of the switch in the APS is connected to the DTI subordinate interface of the TCU.

The translation and translation response packets defined in the DTI protocol spec are 160 bits wide. The interfaces in the topology are all 160 bits wide as indicated in the following figure. No sizers or register slices are part of the topology.

Since the PSS and APS have different clock and power domains, the path between the two DTI Switch instances requires an asynchronous clock domain crossing implementation.

Figure 33. Overall TBU and TCU Connectivity