soc: apple: mailbox: Add ASC/M3 mailbox driver

Signed-off-by: Hector Martin <marcan@marcan.st>

Author: marcan

drivers/soc/apple/Kconfig

@@ -17,6 +17,20 @@ config APPLE_PMGR_PWRSTATE
 	  controls for SoC devices. This driver manages them through the
 	  generic power domain framework, and also provides reset support.
 
+config APPLE_MBOX
+	tristate "Apple SoC mailboxes"
+	depends on PM
+	depends on ARCH_APPLE || (64BIT && COMPILE_TEST)
+	depends on !APPLE_MAILBOX
+	default ARCH_APPLE
+	help
+	  Apple SoCs have various co-processors required for certain
+	  peripherals to work (NVMe, display controller, etc.). This
+	  driver adds support for the mailbox controller used to
+	  communicate with those.
+
+	  Say Y here if you have a Apple SoC.
+
 config APPLE_RTKIT
 	tristate "Apple RTKit co-processor IPC protocol"
 	depends on MAILBOX

drivers/soc/apple/Makefile

@@ -1,6 +1,9 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_APPLE_PMGR_PWRSTATE)	+= apple-pmgr-pwrstate.o
 
+obj-$(CONFIG_APPLE_MBOX) += apple-mailbox.o
+apple-mailbox-y = mailbox.o
+
 obj-$(CONFIG_APPLE_RTKIT) += apple-rtkit.o
 apple-rtkit-y = rtkit.o rtkit-crashlog.o