Introduce the mailbox module for CV18XX series SoC, which is responsible
for interchanging messages between asymmetric processors.
Signed-off-by: Yuntao Dai <d1581209858@live.com>
Signed-off-by: Junhui Liu <junhui.liu@pigmoral.tech>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
