drivers: mbox: Add Arm MHUv3 Mailbox driver

This adds new Arm MHUv3 mailbox driver.

The Arm MHUv3 (Message Handling Unit version 3) is a hardware
block designed for inter-processor communication in SoCs.

The ARM MHUv3 can optionally support various extensions to
enable different kinds of transport to be used for communication.

At the moment only the doorbell extension is supported in the
driver.

For more information refer to Arm Message Handling Unit
Architecture
https://documentation-service.arm.com/static/65f01fbab5e3c10fe1335edf

Signed-off-by: Ziad Elhanafy <[email protected]>

Author: ZiadElhanafy

drivers/mbox/CMakeLists.txt

@@ -21,3 +21,4 @@ zephyr_library_sources_ifdef(CONFIG_MBOX_STM32_HSEM   mbox_stm32_hsem.c)
 zephyr_library_sources_ifdef(CONFIG_MBOX_IVSHMEM mbox_ivshmem.c)
 zephyr_library_sources_ifdef(CONFIG_MBOX_TI_OMAP_MAILBOX   mbox_ti_omap.c)
 zephyr_library_sources_ifdef(CONFIG_MBOX_RENESAS_RZ_MHU mbox_renesas_rz_mhu.c)
+zephyr_library_sources_ifdef(CONFIG_MBOX_MHUV3   mbox_mhuv3.c)

drivers/mbox/Kconfig

@@ -25,6 +25,7 @@ source "drivers/mbox/Kconfig.esp32"
 source "drivers/mbox/Kconfig.ivshmem"
 source "drivers/mbox/Kconfig.ti_omap"
 source "drivers/mbox/Kconfig.renesas_rz"
+source "drivers/mbox/Kconfig.mhuv3"
 
 
 config MBOX_INIT_PRIORITY

drivers/mbox/Kconfig.mhuv3

@@ -0,0 +1,27 @@
+#
+# SPDX-FileCopyrightText: <text>Copyright 2024-2025 Arm Limited and/or its
+# affiliates <[email protected]></text>
+#
+# SPDX-License-Identifier: Apache-2.0
+
+config MBOX_MHUV3
+	bool "ARM MHUv3 mailbox driver"
+	depends on DT_HAS_ARM_MHUV3_ENABLED
+	default y
+	help
+	  Driver for Arm MHUv3 (Message Handling Unit v3)
+
+if MBOX_MHUV3
+
+config MBOX_MHUV3_NUM_DBCH
+	int "ARM MHUv3 mailbox doorbell number of channels"
+	default 0
+	help
+	  Maximum number of doorbell channels allowed in the Postbox/Mailbox.
+	  This number has to be less than or equal to (NUM_DBCH + 1) in PBX_DBCH_CFG0/MBX_DBCH_CFG0 registers.
+	  If the doorbell extension is supported then this number has to be bigger than zero.
+	  MHUv3 allows up to 128 doorbell channels.
+	  This configuration parameter is needed to avoid the dynamic memory allocation of doorbell channels
+	  data structures.
+
+endif