CONFIG_U5500_MBOX is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_U5500_MBOX.
Result is shown for kernelversion 6.2.5
Mailbox support
modulename: mbox-db5500.ko
configname: CONFIG_U5500_MBOX
Linux Kernel Configuration
└─>Mailbox support
In linux kernel since version 2.6.37 (release Date: 2011-01-04)
Add support for U5500 mailbox communication with modem side