Note:
Arm®
AArch64 architecture is common between Zynq UltraScale+ MPSoC APU and the
Versal™
ACAP APU. The existing architectural reference nomenclature
found in the Linux source also applies to Versal
devices.
Linux executes at EL1, and the communication between Linux and the ATF software
layer is realized using SMC calls. Power management features based on the EEMI API have
been ported to the Linux kernel, ensuring that the Linux-centric power management
features use the EEMI services provided by the PMC. Additionally, the EEMI API can be
accessed directly via debugfs
for debugging purposes.
Note that direct access to the EEMI API through debugfs
will interfere with the kernel power management operations and may cause unexpected
problems. All the Linux power management features presented in this chapter are
available in the PetaLinux default configuration.