menuconfig MAILBOX bool "Mailbox Hardware Support" help Mailbox is a framework to control hardware communication between on-chip processors through queued messages and interrupt driven signals. Say Y if your platform supports hardware mailboxes. if MAILBOX config PL320_MBOX bool "ARM PL320 Mailbox" depends on ARM_AMBA help 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. endif