Enabling and utilizing ARM SMMU features can be quite hardware-specific and may require understanding the specific undertale implementation and documentation provided by the hardware manufacturer.

The initialization of the platform is still quite undertale yellow difficult for me, I still cannot complete it
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The Secure Partition Manager (SPM) sets security attributions for flash memory, SRAM, dino game and other peripherals using the System Protection Unit (SPU) peripheral. Security attributions are boolean Kconfig options that allow you to establish security settings such as marking a peripheral as secure or non-secure.