SPRUJC6A December 2024 – July 2025 AM2752-Q1 , AM2754-Q1
The majority of the initiator has a dedicated QoS block to provide the configurability of the transaction characteristic, such as OrderID, priority/epriority, asel and etc. The user can utilize the OrderID and priority/epriority fields to fine tune the performance.
OrderID is a 4 bits value, which is associated with each transaction. By default, all the transactions have orderID value set to 0x0. The OrderID is used as a mechanism to load balance the traffic to DDR through two parallel paths. The transactions with order ID 0-7 share one path, while transactions with 8-15 share a separate path. The OrderID value can be changed through QoS block for the initiators or through BCDMA and pktDMA configuration.
Each transaction in the system carries 3 bits priority information. The priority information is used for interconnect for arbitration decision, which implements typical priority based round robin. Priority value 0x0 is the highest priority, while 0x7 is the lowest priority. By default, QoS has priority value set to 0x7( lowest priority). The priority and epriority can be changed through the QoS block for each initiator.
Some of the modules such as DSS is able to adjust the priority of the transaction based on the system congestion condition. But majority of the transactions have static priority level set by the QoS block. But the priority setting through QoS block can be tuned to fit certain use case scenarios.