RTOS and AMP

V821 can run Linux and an RTOS concurrently.

Linux core
├── remoteproc
├── rpmsg/rpbuf
└── shared memory and mailbox
        ⇅
RTOS core
├── peripheral tasks
└── low-power tasks

RTOS source is under rtos/lichee. Build it with the SDK environment and confirm which generated .bin file is packaged.

Remoteproc control:

cat /sys/class/remoteproc/remoteproc0/state
echo start | sudo tee /sys/class/remoteproc/remoteproc0/state
echo stop  | sudo tee /sys/class/remoteproc/remoteproc0/state

Check shared-memory addresses, cache synchronization, mailbox interrupts, resource tables, and protocol compatibility.