Completion Timer - 4.0 English

QDMA Subsystem for PCI Express Product Guide (PG302)

Document ID
PG302
Release Date
2022-05-20
Version
4.0 English

The Completion Timer engine supports the timer trigger mode in the Completion context. It supports 2048 queues, and each queue has its own timer. When the timer expires, a timer expire signal is sent to the Completion module. If multiple timers expire at the same time, they are sent out in a round robin manner.

Reference Timer

The reference timer is based on the timer tick. The register QDMA_C2H_INT (0xB0C) defines the value of a timer tick. The 16 registers QDMA_C2H_TIMER_CNT (0xA00-0xA3c) has the timer counts based on the timer tick. The timer_idx in the Completion context is the index to the 16 QDMA_C2H_TIMER_CNT registers. Each queue can choose its own timer_idx.