Enable multi-core on rpi_4b

[hcye2022]

Does anyone know how to enable more than 1 cores on rpi_4b (just for AMP not SMP)?

The only value of CONFIG_MP_MAX_NUM_CPUS that compiles is 1. It seems to be due to hardcoded cpus in dts:

cpus {
	#address-cells = < 0x1 >;
	#size-cells = < 0x0 >;
	cpu@0 {
		device_type = "cpu";
		compatible = "arm,cortex-a72";
		reg = < 0x0 >;
	};
};

Does anyone have examples for multiple cpus?