diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 9a62b55..ce51d87 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -931,6 +931,7 @@
 	select DM
 	select DM_GPIO
 	select DM_KEYBOARD
+	select DM_MAILBOX
 	select DM_SERIAL
 	select DM_USB
 	select DM_VIDEO
diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index dd4b0ac..73db2af 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -10,6 +10,17 @@
 	  the basis of a variety of inter-process/inter-CPU communication
 	  protocols.
 
+config APPLE_MBOX
+	bool "Enable Apple IOP controller support"
+	depends on DM_MAILBOX && ARCH_APPLE
+	default y
+	help
+	  Enable support for the mailboxes that provide a comminucation
+	  channel with Apple IOP controllers integrated on Apple SoCs.
+	  These IOP controllers are used to implement various functions
+	  such as the System Management Controller (SMC) and NVMe and this
+	  driver is required to get that functionality up and running.
+
 config SANDBOX_MBOX
 	bool "Enable the sandbox mailbox test driver"
 	depends on DM_MAILBOX && SANDBOX
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index d2ace8c..59e8d0d 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -4,6 +4,7 @@
 #
 
 obj-$(CONFIG_$(SPL_)DM_MAILBOX) += mailbox-uclass.o
+obj-$(CONFIG_APPLE_MBOX) += apple-mbox.o
 obj-$(CONFIG_SANDBOX_MBOX) += sandbox-mbox.o
 obj-$(CONFIG_SANDBOX_MBOX) += sandbox-mbox-test.o
 obj-$(CONFIG_STM32_IPCC) += stm32-ipcc.o
diff --git a/drivers/mailbox/apple-mbox.c b/drivers/mailbox/apple-mbox.c
new file mode 100644
index 0000000..30c8e2f
--- /dev/null
+++ b/drivers/mailbox/apple-mbox.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 Mark Kettenis <kettenis@openbsd.org>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <mailbox-uclass.h>
+#include <asm/io.h>
+#include <linux/apple-mailbox.h>
+#include <linux/delay.h>
+
+#define REG_A2I_STAT	0x110
+#define  REG_A2I_STAT_EMPTY	BIT(17)
+#define  REG_A2I_STAT_FULL	BIT(16)
+#define REG_I2A_STAT	0x114
+#define  REG_I2A_STAT_EMPTY	BIT(17)
+#define  REG_I2A_STAT_FULL	BIT(16)
+#define REG_A2I_MSG0	0x800
+#define REG_A2I_MSG1	0x808
+#define REG_I2A_MSG0	0x830
+#define REG_I2A_MSG1	0x838
+
+struct apple_mbox_priv {
+	void *base;
+};
+
+static int apple_mbox_of_xlate(struct mbox_chan *chan,
+			       struct ofnode_phandle_args *args)
+{
+	if (args->args_count != 0)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int apple_mbox_send(struct mbox_chan *chan, const void *data)
+{
+	struct apple_mbox_priv *priv = dev_get_priv(chan->dev);
+	const struct apple_mbox_msg *msg = data;
+
+	writeq(msg->msg0, priv->base + REG_A2I_MSG0);
+	writeq(msg->msg1, priv->base + REG_A2I_MSG1);
+	while (readl(priv->base + REG_A2I_STAT) & REG_A2I_STAT_FULL)
+		udelay(1);
+
+	return 0;
+}
+
+static int apple_mbox_recv(struct mbox_chan *chan, void *data)
+{
+	struct apple_mbox_priv *priv = dev_get_priv(chan->dev);
+	struct apple_mbox_msg *msg = data;
+
+	if (readl(priv->base + REG_I2A_STAT) & REG_I2A_STAT_EMPTY)
+		return -ENODATA;
+
+	msg->msg0 = readq(priv->base + REG_I2A_MSG0);
+	msg->msg1 = readq(priv->base + REG_I2A_MSG1);
+	return 0;
+}
+
+struct mbox_ops apple_mbox_ops = {
+	.of_xlate = apple_mbox_of_xlate,
+	.send = apple_mbox_send,
+	.recv = apple_mbox_recv,
+};
+
+static int apple_mbox_probe(struct udevice *dev)
+{
+	struct apple_mbox_priv *priv = dev_get_priv(dev);
+
+	priv->base = dev_read_addr_ptr(dev);
+	if (!priv->base)
+		return -EINVAL;
+
+	return 0;
+}
+
+static const struct udevice_id apple_mbox_of_match[] = {
+	{ .compatible = "apple,asc-mailbox-v4" },
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(apple_mbox) = {
+	.name = "apple-mbox",
+	.id = UCLASS_MAILBOX,
+	.of_match = apple_mbox_of_match,
+	.probe = apple_mbox_probe,
+	.priv_auto = sizeof(struct apple_mbox_priv),
+	.ops = &apple_mbox_ops,
+};
diff --git a/include/linux/apple-mailbox.h b/include/linux/apple-mailbox.h
new file mode 100644
index 0000000..720fbb7
--- /dev/null
+++ b/include/linux/apple-mailbox.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-only OR MIT */
+/*
+ * Apple mailbox message format
+ *
+ * Copyright (C) 2021 The Asahi Linux Contributors
+ */
+
+#ifndef _LINUX_APPLE_MAILBOX_H_
+#define _LINUX_APPLE_MAILBOX_H_
+
+#include <linux/types.h>
+
+/* encodes a single 96bit message sent over the single channel */
+struct apple_mbox_msg {
+	u64 msg0;
+	u32 msg1;
+};
+
+#endif