[ranma42]

Its just the reference implementation of the EL3 "Secure world" monitor, and this is where some of the power management stuff is implemented according to ARM standards (e.g. PSCI). Technically I'm pretty sure you could do without it, but then you'd need to amend the devicetree and drivers to handle power state transitions.

On the Rockchip SoC in question, boot security is disabled by default, so you can compile it yourself from source and run your own modified version if you want to.