Intel Agilex® 7 Hard Processor System Remote System Update User Guide

ID 683184
Date 2/23/2024
Public
Document Table of Contents

2.8. Remote System Update Watchdog

The HPS watchdog timer can be used to trigger a reset if it is not serviced periodically. The desired behavior with respect to the RSU flow on such a reset can be selected from Intel® Quartus® Prime tools to be one of the following:
  • Trigger a cold reset – the SDM loads the HPS First Stage Bootloader (FSBL) from the current image and starts it.
  • Trigger a warm reset – the SDM causes the HPS to re-start the HPS FSBL, without reloading it.
  • Trigger a remote system update reconfiguration event – the SDM considers the last loaded application image a failure and then loads the next application image in the CPB, or loads the factory image, if the list is exhausted.

For more information about how to select the HPS watchdog behavior, refer to the Intel® Quartus® Prime eASIC Assembler Software section.

By default, the watchdog is enabled and serviced periodically in both U-Boot SPL and U-Boot.

It is your responsibility to enable and service the watchdog in Linux*, if desired.
Note: The current application image is not removed from the CPB when a watchdog timeout occurs. This means that the image is not permanently marked as unusable and can be tried again (for example after a POR or nCONFIG even happens).