SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The device L3_MAIN interconnect accepts MFLAG signals from certain initiators that can influence the internal L3_MAIN arbitration mechanisms. As a result, a higher priority is given to the data traffic initiated by these initiators. The VIP VPDMA can directly drive such MFLAG signals dynamically. The MFLAG generation for VIP VPDMA is enabled by default, and there is no register control over it.
The VPDMA arbitrates between multiple DMA sources within the VIP based on FIFO levels of DMA channels connected to VPDMA. Priority escalation mechanism implemented within VIP subsystem is based on overflow threshold and FIFO margin.
The following is a summary of priority and MFLAG levels provided by the VIP:
Additionally, the VIP subsystem also generates MReqPriority based upon a programmed descriptor configuration. The MReqPriority configuration influences the arbitration mechanism in the Memory Subsystem only and has no influence on the arbitration that takes place within L3_MAIN interconnect. For more information see Section 11.4.8.8.1.4, Data Packet Descriptor Word 3.