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Get Memory Mapping Parameters in Auto Mode

Last modified by Microchip on 2026/08/17 12:12

If the method described in "Automatically Save and Load Snapshot Image Mode" is used, you do not need to obtain the memory mapping parameters because the system handles these parameters internally.

In Restore mode,  when a suspend request is initialized, the Linux® kernel saves the resume code and suspend status in SECURAM. As a result, there is no need to configure these parameters manually. Instead, this mode requires the Ultra-Fast Boot kernel patch. See the "Apply Kernel Patch to Support Ultra-Fast Boot" page for more details.

When a wake-up event is detected from the suspend state, at91bootstrap starts and checks the suspend status in SECURAM and whether the Double Data Rate (DDR) is in the self-refresh state.

If the system is suspended in PM mode for RESTORE and FAST_BOOT is enabled, at91bootstrap will exit DDR self-refresh. If no valid snapshot image has been found on an external Non-Volatile Memory (NVM), at91bootstrap reads these parameters from SECURAM to analyze the memory mapping and then saves the DDR context as a snapshot image to flash memory.