Intel® Agilex™ Configuration User Guide

ID 683673
Date 10/29/2021

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Document Table of Contents RSU Image Layout in Flash – SDM Perspective

In the RSU case, decision firmware replaces the standard firmware. The decision firmware copies have pointers to the following structures in flash:

  • Decision firmware data
  • One factory image
  • Two configuration pointer blocks (CPBs)
Figure 68. RSU Image Layout in Flash : SDM PerspectiveIn this figure:
  • Each of the Decision Firmware copies point to the Factory Image and both Pointer Block 0 and Pointer Block 1.
  • Both Pointer Block 0 and Pointer Block 1 point to Application Images.

The decision firmware data stores basic settings, including the following:

  • The clock and pins that connect to quad SPI flash memory
  • The Direct to Factory Image pin that forces the SDM to load the factory image
    Note: You can set this pin on the following menu in the factory image project: Assignments > Device > Device and Pin Options > Configuration > Configuration Pin Options
  • The max_retry parameter value.

    The max_retry value, stored as an 8-bit value at address 0x10018C in flash, is the only accessible field from the decision firmware data structure. The value in flash is max_retry - 1. That is, a value of zero means each image is tried just once. Modification of the max_retry value directly in the bitstream stored in flash is typically used by RSU via HPS. For more information, refer to Intel® Agilex™ Hard Processor System Remote System Update User Guide.

The pointer blocks contain a list of application images to try until one of them is successful. If none is successful, the SDM loads the factory image. To ensure reliability, the pointer block includes a main and a backup copy in case an update operation fails.

Both the factory image and the application images start with firmware. First, the decision firmware loads the firmware. Then, that firmware loads the rest of the image. These implementation details are not shown in the figure above. For more information, refer to the Application Image Layout section.