Mailbox Test Client

modulename: mailbox-test.ko

configname: CONFIG_MAILBOX_TEST

Linux Kernel Configuration
└─>Device Drivers
└─>Mailbox Hardware Support
└─>Device Tree and Open Firmware support
└─>Mailbox Test Client
In linux kernel since version 4.1 (release Date: 2015-06-21)  
Test client to help with testing new Controller driver
implementations.

source code:
drivers/mailbox/mailbox-test.c