Resolved! OpenAMP hangs at MX_OPENAMP_Init() when started from U-Boot, even after waited for linux to fully booted up.
When I run the openamp image through linux command prompt, the application working fine. The RPMSG devices is created successfully.But when I've tried to run it from uboot, it stuck at MX_OPENAMP_Init(). This should be ok because I assume linux isn't...