Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 11/27/2024
Public
Document Table of Contents

4.1.5.3.2. Coherent Clean Request

The following figure shows the coherent clean request.

Figure 22. Coherent Clean Request

In a coherent clean request:

  • CMD message is issued from an AIU to a DCE. In the DCE, a coherent clean transaction behaves similarly to a coherent read transaction, and SNP messages are issued to the appropriate AIUs.
  • Additionally, RB is issued to DMI. In this case, however, if a caching agent has a modified copy of data, the AIU issues a DTW message to DMI to update the memory with the most recent value.

After memory has been updated and all the SNP message responses have been gathered, the DCE issues and completes an STR message.