1\ingroup GroupModules Modules 2\defgroup GroupMHU3 MHU Hardware version 3 driver. 3 4# MHU Hardware version 3 driver 5 6 7Copyright (c) 2022, Arm Limited and Contributors. All rights reserved. 8 9## Overview 10 11This is a driver module that supports MHU hardware version 3. 12 13Although, MHUv3 specifications specify various extensions, at the moment, only 14the following extensions are supported by this driver: 15 161. Doorbell Channel extension 172. Fast Channel extension 18 19### Limitations 20 21Doorbell channel implementation is limited to 32 doorbell channels for 22efficiency reasons. 23 24However, this can be extended to support more on a larger system with more 25powerful processors. In general, although MHUv3 specification allows up to 128 26channels, on a practical system for a SCP use case, the number of doorbell 27channels is expected to remain < 32. 28