AMP Boot Configurations
Boot configurations
10.1 Linux + AP RTOS/bare metal
U-Boot runs on CPU0, loads the specified remote-core firmware from amp.img, releases the target CPU, and then continues to boot Linux. Linux starts only the CPUs assigned to its SMP domain.
For example, on a four-core SoC where CPU3 runs RT-Thread:
BootROM/Loader → U-Boot@CPU0 → RT-Thread@CPU3
└──→ Linux@CPU0/CPU1/CPU210.2 Linux + MCU RTOS/bare metal
U-Boot loads and releases the MCU before continuing to boot Linux on the AP. The MCU node type must match the platform U-Boot implementation. Rockchip examples normally use standalone.
10.3 RTOS + bare metal
U-Boot loads the firmware for each CPU according to loadables. When CPU0 is the boot core, U-Boot normally releases the other CPUs first and finally jumps to the CPU0 firmware.
10.4 Fast boot
Some SoCs can load MCU firmware earlier in the SPL stage, or use an SPI NOR + eMMC dual-storage design to reduce MCU startup time. These solutions require coordinated changes to rkbin and U-Boot and must use a configuration designed for the target SoC. Do not reuse such configurations across platforms.