mailbox: apple: Add driver for Apple mailboxes

Apple SoCs such as the M1 come with various co-processors. Mailboxes
are used to communicate with those. This driver adds support for
two variants of those mailboxes.

Signed-off-by: Sven Peter <[email protected]>
Signed-off-by: Jassi Brar <[email protected]>

Author: svenpeter42

drivers/mailbox/Kconfig

@@ -8,6 +8,18 @@ menuconfig MAILBOX
 
 if MAILBOX
 
+config APPLE_MAILBOX
+	tristate "Apple Mailbox driver"
+	depends on ARCH_APPLE || (ARM64 && COMPILE_TEST)
+	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 ARM_MHU
 	tristate "ARM MHU Mailbox"
 	depends on ARM_AMBA

drivers/mailbox/Makefile

@@ -58,3 +58,5 @@ obj-$(CONFIG_SUN6I_MSGBOX)	+= sun6i-msgbox.o
 obj-$(CONFIG_SPRD_MBOX)		+= sprd-mailbox.o
 
 obj-$(CONFIG_QCOM_IPCC)		+= qcom-ipcc.o
+
+obj-$(CONFIG_APPLE_MAILBOX)	+= apple-mailbox.o