ARM PL320 Mailbox

modulename: pl320-ipc.ko

configname: CONFIG_PL320_MBOX

Linux Kernel Configuration
└─>Device Drivers
└─>Mailbox Hardware Support
└─>ARM PL320 Mailbox
In linux kernel since version 3.1 (release Date: 2011-10-24)  
An implementation of the ARM PL320 Interprocessor Communication
Mailbox (IPCM), tailored for the Calxeda Highbank. It is used to
send short messages between Highbank's A9 cores and the EnergyCore
Management Engine, primarily for cpufreq. Say Y here if you want
to use the PL320 IPCM support.

source code: