TXDAT

Functional Description

The TXDAT module unconditionally accepts requests from the MainPipe destined for the WDAT channel, buffers them in a queue, and ultimately sends them to the CHI TXDAT bus channel. The TXDAT module must control the flow at the MainPipe entry to ensure that requests on the MainPipe can enter TXDAT without being blocked.

Functional Description

Feature 1: Backpressure on the MainPipe

To ensure that requests on the MainPipe can non-blockingly enter TXDAT at stages s3/s4/s5, when [the number of requests on the MainPipe that may need to enter TXDAT + the number of valid entries in the queue ≥ the total queue capacity], the TXDAT module must apply backpressure to the MainPipe entry stages, i.e., s0/s1. 1. Backpressure is applied at stage s1 because snoops received by RXSNP may be directly processed on the MainPipe and then enter the TXDAT channel, so backpressure must be applied to the sinkB requests at s1. 2. Backpressure is applied at stage s0 because some MSHR tasks need to enter the TXDAT channel. Since MSHR tasks enter the pipeline at s0, backpressure must be applied to the mshrTask at s0.

TXDAT