DDRC QOS Mechanism Overview
===========================

Transmission Type
-----------------

Read direction: Low Priority Read (LPR), Variable Priority Read (VPR), High Priority Read
(HPR)

Write direction: Priority Write (NPW), Variable Priority Write (VPW)

Transmission types:

======== ========== ==================== ===================
Type     Direction  Has Dedicated CAM?   Support Timeout?
======== ========== ==================== ===================
LPR      READ       No                   No
VPR      READ       No                   Yes
HPR      READ       Yes                  No
NPW      WRITE      No                   No
VPW      WRITE      No                   Yes
======== ========== ==================== ===================

QOS Mapping Relationships
-------------------------

According to the *arqos/awqos* signals of the AXI protocol, you can map the master transmission to different types, as follows:


.. image:: media_en/00de335c3b755c6fba5ec5b1679c9d2d.png


You can map the *region* type of each port by configuring the PCFGQOS_n and PCFGWQOS_n registers, and the boundaries of each region are defined by *level*, refer to :ref:`Related Register Descriptions <register>`.
