6 files changed, 533 insertions, 112 deletions

diff --git a/drivers/soc/apple/Kconfig b/drivers/soc/apple/Kconfig
index eff486a77337..6388cbe1e56b 100644
--- a/drivers/soc/apple/Kconfig
+++ b/drivers/soc/apple/Kconfig
@@ -4,9 +4,22 @@ if ARCH_APPLE || COMPILE_TEST
 
 menu "Apple SoC drivers"
 
+config APPLE_MAILBOX
+	tristate "Apple SoC mailboxes"
+	depends on PM
+	depends on ARCH_APPLE || (64BIT && 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 an Apple SoC.
+
 config APPLE_RTKIT
 	tristate "Apple RTKit co-processor IPC protocol"
-	depends on MAILBOX
+	depends on APPLE_MAILBOX
 	depends on ARCH_APPLE || COMPILE_TEST
 	default ARCH_APPLE
 	help
diff --git a/drivers/soc/apple/Makefile b/drivers/soc/apple/Makefile
index b241e6a65e5b..4d9ab8f3037b 100644
--- a/drivers/soc/apple/Makefile
+++ b/drivers/soc/apple/Makefile
@@ -1,4 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_APPLE_MAILBOX) += apple-mailbox.o
+apple-mailbox-y = mailbox.o
+
 obj-$(CONFIG_APPLE_RTKIT) += apple-rtkit.o
 apple-rtkit-y = rtkit.o rtkit-crashlog.o
 
diff --git a/drivers/soc/apple/mailbox.c b/drivers/soc/apple/mailbox.c
new file mode 100644
index 000000000000..780199bf351e
--- /dev/null
+++ b/drivers/soc/apple/mailbox.c
@@ -0,0 +1,437 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * Apple mailbox driver
+ *
+ * Copyright The Asahi Linux Contributors
+ *
+ * This driver adds support for two mailbox variants (called ASC and M3 by
+ * Apple) found in Apple SoCs such as the M1. It consists of two FIFOs used to
+ * exchange 64+32 bit messages between the main CPU and a co-processor.
+ * Various coprocessors implement different IPC protocols based on these simple
+ * messages and shared memory buffers.
+ *
+ * Both the main CPU and the co-processor see the same set of registers but
+ * the first FIFO (A2I) is always used to transfer messages from the application
+ * processor (us) to the I/O processor and the second one (I2A) for the
+ * other direction.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include "mailbox.h"
+
+#define APPLE_ASC_MBOX_CONTROL_FULL BIT(16)
+#define APPLE_ASC_MBOX_CONTROL_EMPTY BIT(17)
+
+#define APPLE_ASC_MBOX_A2I_CONTROL 0x110
+#define APPLE_ASC_MBOX_A2I_SEND0 0x800
+#define APPLE_ASC_MBOX_A2I_SEND1 0x808
+#define APPLE_ASC_MBOX_A2I_RECV0 0x810
+#define APPLE_ASC_MBOX_A2I_RECV1 0x818
+
+#define APPLE_ASC_MBOX_I2A_CONTROL 0x114
+#define APPLE_ASC_MBOX_I2A_SEND0 0x820
+#define APPLE_ASC_MBOX_I2A_SEND1 0x828
+#define APPLE_ASC_MBOX_I2A_RECV0 0x830
+#define APPLE_ASC_MBOX_I2A_RECV1 0x838
+
+#define APPLE_M3_MBOX_CONTROL_FULL BIT(16)
+#define APPLE_M3_MBOX_CONTROL_EMPTY BIT(17)
+
+#define APPLE_M3_MBOX_A2I_CONTROL 0x50
+#define APPLE_M3_MBOX_A2I_SEND0 0x60
+#define APPLE_M3_MBOX_A2I_SEND1 0x68
+#define APPLE_M3_MBOX_A2I_RECV0 0x70
+#define APPLE_M3_MBOX_A2I_RECV1 0x78
+
+#define APPLE_M3_MBOX_I2A_CONTROL 0x80
+#define APPLE_M3_MBOX_I2A_SEND0 0x90
+#define APPLE_M3_MBOX_I2A_SEND1 0x98
+#define APPLE_M3_MBOX_I2A_RECV0 0xa0
+#define APPLE_M3_MBOX_I2A_RECV1 0xa8
+
+#define APPLE_M3_MBOX_IRQ_ENABLE 0x48
+#define APPLE_M3_MBOX_IRQ_ACK 0x4c
+#define APPLE_M3_MBOX_IRQ_A2I_EMPTY BIT(0)
+#define APPLE_M3_MBOX_IRQ_A2I_NOT_EMPTY BIT(1)
+#define APPLE_M3_MBOX_IRQ_I2A_EMPTY BIT(2)
+#define APPLE_M3_MBOX_IRQ_I2A_NOT_EMPTY BIT(3)
+
+#define APPLE_MBOX_MSG1_OUTCNT GENMASK(56, 52)
+#define APPLE_MBOX_MSG1_INCNT GENMASK(51, 48)
+#define APPLE_MBOX_MSG1_OUTPTR GENMASK(47, 44)
+#define APPLE_MBOX_MSG1_INPTR GENMASK(43, 40)
+#define APPLE_MBOX_MSG1_MSG GENMASK(31, 0)
+
+#define APPLE_MBOX_TX_TIMEOUT 500
+
+struct apple_mbox_hw {
+	unsigned int control_full;
+	unsigned int control_empty;
+
+	unsigned int a2i_control;
+	unsigned int a2i_send0;
+	unsigned int a2i_send1;
+
+	unsigned int i2a_control;
+	unsigned int i2a_recv0;
+	unsigned int i2a_recv1;
+
+	bool has_irq_controls;
+	unsigned int irq_enable;
+	unsigned int irq_ack;
+	unsigned int irq_bit_recv_not_empty;
+	unsigned int irq_bit_send_empty;
+};
+
+int apple_mbox_send(struct apple_mbox *mbox, const struct apple_mbox_msg msg,
+		    bool atomic)
+{
+	unsigned long flags;
+	int ret;
+	u32 mbox_ctrl;
+	long t;
+
+	spin_lock_irqsave(&mbox->tx_lock, flags);
+	mbox_ctrl = readl_relaxed(mbox->regs + mbox->hw->a2i_control);
+
+	while (mbox_ctrl & mbox->hw->control_full) {
+		if (atomic) {
+			ret = readl_poll_timeout_atomic(
+				mbox->regs + mbox->hw->a2i_control, mbox_ctrl,
+				!(mbox_ctrl & mbox->hw->control_full), 100,
+				APPLE_MBOX_TX_TIMEOUT * 1000);
+
+			if (ret) {
+				spin_unlock_irqrestore(&mbox->tx_lock, flags);
+				return ret;
+			}
+
+			break;
+		}
+		/*
+		 * The interrupt is level triggered and will keep firing as long as the
+		 * FIFO is empty. It will also keep firing if the FIFO was empty
+		 * at any point in the past until it has been acknowledged at the
+		 * mailbox level. By acknowledging it here we can ensure that we will
+		 * only get the interrupt once the FIFO has been cleared again.
+		 * If the FIFO is already empty before the ack it will fire again
+		 * immediately after the ack.
+		 */
+		if (mbox->hw->has_irq_controls) {
+			writel_relaxed(mbox->hw->irq_bit_send_empty,
+				       mbox->regs + mbox->hw->irq_ack);
+		}
+		enable_irq(mbox->irq_send_empty);
+		reinit_completion(&mbox->tx_empty);
+		spin_unlock_irqrestore(&mbox->tx_lock, flags);
+
+		t = wait_for_completion_interruptible_timeout(
+			&mbox->tx_empty,
+			msecs_to_jiffies(APPLE_MBOX_TX_TIMEOUT));
+		if (t < 0)
+			return t;
+		else if (t == 0)
+			return -ETIMEDOUT;
+
+		spin_lock_irqsave(&mbox->tx_lock, flags);
+		mbox_ctrl = readl_relaxed(mbox->regs + mbox->hw->a2i_control);
+	}
+
+	writeq_relaxed(msg.msg0, mbox->regs + mbox->hw->a2i_send0);
+	writeq_relaxed(FIELD_PREP(APPLE_MBOX_MSG1_MSG, msg.msg1),
+		       mbox->regs + mbox->hw->a2i_send1);
+
+	spin_unlock_irqrestore(&mbox->tx_lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL(apple_mbox_send);
+
+static irqreturn_t apple_mbox_send_empty_irq(int irq, void *data)
+{
+	struct apple_mbox *mbox = data;
+
+	/*
+	 * We don't need to acknowledge the interrupt at the mailbox level
+	 * here even if supported by the hardware. It will keep firing but that
+	 * doesn't matter since it's disabled at the main interrupt controller.
+	 * apple_mbox_send will acknowledge it before enabling
+	 * it at the main controller again.
+	 */
+	spin_lock(&mbox->tx_lock);
+	disable_irq_nosync(mbox->irq_send_empty);
+	complete(&mbox->tx_empty);
+	spin_unlock(&mbox->tx_lock);
+
+	return IRQ_HANDLED;
+}
+
+static int apple_mbox_poll_locked(struct apple_mbox *mbox)
+{
+	struct apple_mbox_msg msg;
+	int ret = 0;
+
+	u32 mbox_ctrl = readl_relaxed(mbox->regs + mbox->hw->i2a_control);
+
+	while (!(mbox_ctrl & mbox->hw->control_empty)) {
+		msg.msg0 = readq_relaxed(mbox->regs + mbox->hw->i2a_recv0);
+		msg.msg1 = FIELD_GET(
+			APPLE_MBOX_MSG1_MSG,
+			readq_relaxed(mbox->regs + mbox->hw->i2a_recv1));
+
+		mbox->rx(mbox, msg, mbox->cookie);
+		ret++;
+		mbox_ctrl = readl_relaxed(mbox->regs + mbox->hw->i2a_control);
+	}
+
+	/*
+	 * The interrupt will keep firing even if there are no more messages
+	 * unless we also acknowledge it at the mailbox level here.
+	 * There's no race if a message comes in between the check in the while
+	 * loop above and the ack below: If a new messages arrives inbetween
+	 * those two the interrupt will just fire again immediately after the
+	 * ack since it's level triggered.
+	 */
+	if (mbox->hw->has_irq_controls) {
+		writel_relaxed(mbox->hw->irq_bit_recv_not_empty,
+			       mbox->regs + mbox->hw->irq_ack);
+	}
+
+	return ret;
+}
+
+static irqreturn_t apple_mbox_recv_irq(int irq, void *data)
+{
+	struct apple_mbox *mbox = data;
+
+	spin_lock(&mbox->rx_lock);
+	apple_mbox_poll_locked(mbox);
+	spin_unlock(&mbox->rx_lock);
+
+	return IRQ_HANDLED;
+}
+
+int apple_mbox_poll(struct apple_mbox *mbox)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&mbox->rx_lock, flags);
+	ret = apple_mbox_poll_locked(mbox);
+	spin_unlock_irqrestore(&mbox->rx_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(apple_mbox_poll);
+
+int apple_mbox_start(struct apple_mbox *mbox)
+{
+	int ret;
+
+	if (mbox->active)
+		return 0;
+
+	ret = pm_runtime_resume_and_get(mbox->dev);
+	if (ret)
+		return ret;
+
+	/*
+	 * Only some variants of this mailbox HW provide interrupt control
+	 * at the mailbox level. We therefore need to handle enabling/disabling
+	 * interrupts at the main interrupt controller anyway for hardware that
+	 * doesn't. Just always keep the interrupts we care about enabled at
+	 * the mailbox level so that both hardware revisions behave almost
+	 * the same.
+	 */
+	if (mbox->hw->has_irq_controls) {
+		writel_relaxed(mbox->hw->irq_bit_recv_not_empty |
+				       mbox->hw->irq_bit_send_empty,
+			       mbox->regs + mbox->hw->irq_enable);
+	}
+
+	enable_irq(mbox->irq_recv_not_empty);
+	mbox->active = true;
+	return 0;
+}
+EXPORT_SYMBOL(apple_mbox_start);
+
+void apple_mbox_stop(struct apple_mbox *mbox)
+{
+	if (!mbox->active)
+		return;
+
+	mbox->active = false;
+	disable_irq(mbox->irq_recv_not_empty);
+	pm_runtime_mark_last_busy(mbox->dev);
+	pm_runtime_put_autosuspend(mbox->dev);
+}
+EXPORT_SYMBOL(apple_mbox_stop);
+
+struct apple_mbox *apple_mbox_get(struct device *dev, int index)
+{
+	struct of_phandle_args args;
+	struct platform_device *pdev;
+	struct apple_mbox *mbox;
+	int ret;
+
+	ret = of_parse_phandle_with_args(dev->of_node, "mboxes", "#mbox-cells",
+					 index, &args);
+	if (ret || !args.np)
+		return ERR_PTR(ret);
+
+	pdev = of_find_device_by_node(args.np);
+	of_node_put(args.np);
+
+	if (!pdev)
+		return ERR_PTR(EPROBE_DEFER);
+
+	mbox = platform_get_drvdata(pdev);
+	if (!mbox)
+		return ERR_PTR(EPROBE_DEFER);
+
+	if (!device_link_add(dev, &pdev->dev, DL_FLAG_AUTOREMOVE_CONSUMER))
+		return ERR_PTR(ENODEV);
+
+	return mbox;
+}
+EXPORT_SYMBOL(apple_mbox_get);
+
+struct apple_mbox *apple_mbox_get_byname(struct device *dev, const char *name)
+{
+	int index;
+
+	index = of_property_match_string(dev->of_node, "mbox-names", name);
+	if (index < 0)
+		return ERR_PTR(index);
+
+	return apple_mbox_get(dev, index);
+}
+EXPORT_SYMBOL(apple_mbox_get_byname);
+
+static int apple_mbox_probe(struct platform_device *pdev)
+{
+	int ret;
+	char *irqname;
+	struct apple_mbox *mbox;
+	struct device *dev = &pdev->dev;
+
+	mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
+	if (!mbox)
+		return -ENOMEM;
+
+	mbox->dev = &pdev->dev;
+	mbox->hw = of_device_get_match_data(dev);
+	if (!mbox->hw)
+		return -EINVAL;
+
+	mbox->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(mbox->regs))
+		return PTR_ERR(mbox->regs);
+
+	mbox->irq_recv_not_empty =
+		platform_get_irq_byname(pdev, "recv-not-empty");
+	if (mbox->irq_recv_not_empty < 0)
+		return -ENODEV;
+
+	mbox->irq_send_empty = platform_get_irq_byname(pdev, "send-empty");
+	if (mbox->irq_send_empty < 0)
+		return -ENODEV;
+
+	spin_lock_init(&mbox->rx_lock);
+	spin_lock_init(&mbox->tx_lock);
+	init_completion(&mbox->tx_empty);
+
+	irqname = devm_kasprintf(dev, GFP_KERNEL, "%s-recv", dev_name(dev));
+	if (!irqname)
+		return -ENOMEM;
+
+	ret = devm_request_irq(dev, mbox->irq_recv_not_empty,
+			       apple_mbox_recv_irq,
+			       IRQF_NO_AUTOEN | IRQF_NO_SUSPEND, irqname, mbox);
+	if (ret)
+		return ret;
+
+	irqname = devm_kasprintf(dev, GFP_KERNEL, "%s-send", dev_name(dev));
+	if (!irqname)
+		return -ENOMEM;
+
+	ret = devm_request_irq(dev, mbox->irq_send_empty,
+			       apple_mbox_send_empty_irq,
+			       IRQF_NO_AUTOEN | IRQF_NO_SUSPEND, irqname, mbox);
+	if (ret)
+		return ret;
+
+	ret = devm_pm_runtime_enable(dev);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, mbox);
+	return 0;
+}
+
+static const struct apple_mbox_hw apple_mbox_asc_hw = {
+	.control_full = APPLE_ASC_MBOX_CONTROL_FULL,
+	.control_empty = APPLE_ASC_MBOX_CONTROL_EMPTY,
+
+	.a2i_control = APPLE_ASC_MBOX_A2I_CONTROL,
+	.a2i_send0 = APPLE_ASC_MBOX_A2I_SEND0,
+	.a2i_send1 = APPLE_ASC_MBOX_A2I_SEND1,
+
+	.i2a_control = APPLE_ASC_MBOX_I2A_CONTROL,
+	.i2a_recv0 = APPLE_ASC_MBOX_I2A_RECV0,
+	.i2a_recv1 = APPLE_ASC_MBOX_I2A_RECV1,
+
+	.has_irq_controls = false,
+};
+
+static const struct apple_mbox_hw apple_mbox_m3_hw = {
+	.control_full = APPLE_M3_MBOX_CONTROL_FULL,
+	.control_empty = APPLE_M3_MBOX_CONTROL_EMPTY,
+
+	.a2i_control = APPLE_M3_MBOX_A2I_CONTROL,
+	.a2i_send0 = APPLE_M3_MBOX_A2I_SEND0,
+	.a2i_send1 = APPLE_M3_MBOX_A2I_SEND1,
+
+	.i2a_control = APPLE_M3_MBOX_I2A_CONTROL,
+	.i2a_recv0 = APPLE_M3_MBOX_I2A_RECV0,
+	.i2a_recv1 = APPLE_M3_MBOX_I2A_RECV1,
+
+	.has_irq_controls = true,
+	.irq_enable = APPLE_M3_MBOX_IRQ_ENABLE,
+	.irq_ack = APPLE_M3_MBOX_IRQ_ACK,
+	.irq_bit_recv_not_empty = APPLE_M3_MBOX_IRQ_I2A_NOT_EMPTY,
+	.irq_bit_send_empty = APPLE_M3_MBOX_IRQ_A2I_EMPTY,
+};
+
+static const struct of_device_id apple_mbox_of_match[] = {
+	{ .compatible = "apple,asc-mailbox-v4", .data = &apple_mbox_asc_hw },
+	{ .compatible = "apple,m3-mailbox-v2", .data = &apple_mbox_m3_hw },
+	{}
+};
+MODULE_DEVICE_TABLE(of, apple_mbox_of_match);
+
+static struct platform_driver apple_mbox_driver = {
+	.driver = {
+		.name = "apple-mailbox",
+		.of_match_table = apple_mbox_of_match,
+	},
+	.probe = apple_mbox_probe,
+};
+module_platform_driver(apple_mbox_driver);
+
+MODULE_LICENSE("Dual MIT/GPL");
+MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>");
+MODULE_DESCRIPTION("Apple Mailbox driver");
diff --git a/drivers/soc/apple/mailbox.h b/drivers/soc/apple/mailbox.h
new file mode 100644
index 000000000000..f73a8913da95
--- /dev/null
+++ b/drivers/soc/apple/mailbox.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0-only OR MIT */
+/*
+ * Apple mailbox message format
+ *
+ * Copyright The Asahi Linux Contributors
+ */
+
+#ifndef _APPLE_MAILBOX_H_
+#define _APPLE_MAILBOX_H_
+
+#include <linux/device.h>
+#include <linux/types.h>
+
+/* encodes a single 96bit message sent over the single channel */
+struct apple_mbox_msg {
+	u64 msg0;
+	u32 msg1;
+};
+
+struct apple_mbox {
+	struct device *dev;
+	void __iomem *regs;
+	const struct apple_mbox_hw *hw;
+	bool active;
+
+	int irq_recv_not_empty;
+	int irq_send_empty;
+
+	spinlock_t rx_lock;
+	spinlock_t tx_lock;
+
+	struct completion tx_empty;
+
+	/** Receive callback for incoming messages */
+	void (*rx)(struct apple_mbox *mbox, struct apple_mbox_msg msg, void *cookie);
+	void *cookie;
+};
+
+struct apple_mbox *apple_mbox_get(struct device *dev, int index);
+struct apple_mbox *apple_mbox_get_byname(struct device *dev, const char *name);
+
+int apple_mbox_start(struct apple_mbox *mbox);
+void apple_mbox_stop(struct apple_mbox *mbox);
+int apple_mbox_poll(struct apple_mbox *mbox);
+int apple_mbox_send(struct apple_mbox *mbox, struct apple_mbox_msg msg,
+		    bool atomic);
+
+#endif
diff --git a/drivers/soc/apple/rtkit-internal.h b/drivers/soc/apple/rtkit-internal.h
index 24bd619ec5e4..27c9fa745fd5 100644
--- a/drivers/soc/apple/rtkit-internal.h
+++ b/drivers/soc/apple/rtkit-internal.h
@@ -7,18 +7,17 @@
 #ifndef _APPLE_RTKIT_INTERAL_H
 #define _APPLE_RTKIT_INTERAL_H
 
-#include <linux/apple-mailbox.h>
 #include <linux/bitfield.h>
 #include <linux/bitmap.h>
 #include <linux/completion.h>
 #include <linux/dma-mapping.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
-#include <linux/mailbox_client.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/soc/apple/rtkit.h>
 #include <linux/workqueue.h>
+#include "mailbox.h"
 
 #define APPLE_RTKIT_APP_ENDPOINT_START 0x20
 #define APPLE_RTKIT_MAX_ENDPOINTS 0x100
@@ -28,10 +27,7 @@ struct apple_rtkit {
 	const struct apple_rtkit_ops *ops;
 	struct device *dev;
 
-	const char *mbox_name;
-	int mbox_idx;
-	struct mbox_client mbox_cl;
-	struct mbox_chan *mbox_chan;
+	struct apple_mbox *mbox;
 
 	struct completion epmap_completion;
 	struct completion iop_pwr_ack_completion;
diff --git a/drivers/soc/apple/rtkit.c b/drivers/soc/apple/rtkit.c
index d9f19dc99da5..e6d940292c9f 100644
--- a/drivers/soc/apple/rtkit.c
+++ b/drivers/soc/apple/rtkit.c
@@ -72,11 +72,6 @@ enum {
 #define APPLE_RTKIT_MIN_SUPPORTED_VERSION 11
 #define APPLE_RTKIT_MAX_SUPPORTED_VERSION 12
 
-struct apple_rtkit_msg {
-	struct completion *completion;
-	struct apple_mbox_msg mbox_msg;
-};
-
 struct apple_rtkit_rx_work {
 	struct apple_rtkit *rtk;
 	u8 ep;
@@ -550,12 +545,12 @@ static void apple_rtkit_rx_work(struct work_struct *work)
 	kfree(rtk_work);
 }
 
-static void apple_rtkit_rx(struct mbox_client *cl, void *mssg)
+static void apple_rtkit_rx(struct apple_mbox *mbox, struct apple_mbox_msg msg,
+			   void *cookie)
 {
-	struct apple_rtkit *rtk = container_of(cl, struct apple_rtkit, mbox_cl);
-	struct apple_mbox_msg *msg = mssg;
+	struct apple_rtkit *rtk = cookie;
 	struct apple_rtkit_rx_work *work;
-	u8 ep = msg->msg1;
+	u8 ep = msg.msg1;
 
 	/*
 	 * The message was read from a MMIO FIFO and we have to make
@@ -571,7 +566,7 @@ static void apple_rtkit_rx(struct mbox_client *cl, void *mssg)
 
 	if (ep >= APPLE_RTKIT_APP_ENDPOINT_START &&
 	    rtk->ops->recv_message_early &&
-	    rtk->ops->recv_message_early(rtk->cookie, ep, msg->msg0))
+	    rtk->ops->recv_message_early(rtk->cookie, ep, msg.msg0))
 		return;
 
 	work = kzalloc(sizeof(*work), GFP_ATOMIC);
@@ -580,30 +575,18 @@ static void apple_rtkit_rx(struct mbox_client *cl, void *mssg)
 
 	work->rtk = rtk;
 	work->ep = ep;
-	work->msg = msg->msg0;
+	work->msg = msg.msg0;
 	INIT_WORK(&work->work, apple_rtkit_rx_work);
 	queue_work(rtk->wq, &work->work);
 }
 
-static void apple_rtkit_tx_done(struct mbox_client *cl, void *mssg, int r)
-{
-	struct apple_rtkit_msg *msg =
-		container_of(mssg, struct apple_rtkit_msg, mbox_msg);
-
-	if (r == -ETIME)
-		return;
-
-	if (msg->completion)
-		complete(msg->completion);
-	kfree(msg);
-}
-
 int apple_rtkit_send_message(struct apple_rtkit *rtk, u8 ep, u64 message,
 			     struct completion *completion, bool atomic)
 {
-	struct apple_rtkit_msg *msg;
-	int ret;
-	gfp_t flags;
+	struct apple_mbox_msg msg = {
+		.msg0 = message,
+		.msg1 = ep,
+	};
 
 	if (rtk->crashed)
 		return -EINVAL;
@@ -611,19 +594,6 @@ int apple_rtkit_send_message(struct apple_rtkit *rtk, u8 ep, u64 message,
 	    !apple_rtkit_is_running(rtk))
 		return -EINVAL;
 
-	if (atomic)
-		flags = GFP_ATOMIC;
-	else
-		flags = GFP_KERNEL;
-
-	msg = kzalloc(sizeof(*msg), flags);
-	if (!msg)
-		return -ENOMEM;
-
-	msg->mbox_msg.msg0 = message;
-	msg->mbox_msg.msg1 = ep;
-	msg->completion = completion;
-
 	/*
 	 * The message will be sent with a MMIO write. We need the barrier
 	 * here to ensure any previous writes to buffers are visible to the
@@ -631,51 +601,13 @@ int apple_rtkit_send_message(struct apple_rtkit *rtk, u8 ep, u64 message,
 	 */
 	dma_wmb();
 
-	ret = mbox_send_message(rtk->mbox_chan, &msg->mbox_msg);
-	if (ret < 0) {
-		kfree(msg);
-		return ret;
-	}
-
-	return 0;
+	return apple_mbox_send(rtk->mbox, msg, atomic);
 }
 EXPORT_SYMBOL_GPL(apple_rtkit_send_message);
 
-int apple_rtkit_send_message_wait(struct apple_rtkit *rtk, u8 ep, u64 message,
-				  unsigned long timeout, bool atomic)
-{
-	DECLARE_COMPLETION_ONSTACK(completion);
-	int ret;
-	long t;
-
-	ret = apple_rtkit_send_message(rtk, ep, message, &completion, atomic);
-	if (ret < 0)
-		return ret;
-
-	if (atomic) {
-		ret = mbox_flush(rtk->mbox_chan, timeout);
-		if (ret < 0)
-			return ret;
-
-		if (try_wait_for_completion(&completion))
-			return 0;
-
-		return -ETIME;
-	} else {
-		t = wait_for_completion_interruptible_timeout(
-			&completion, msecs_to_jiffies(timeout));
-		if (t < 0)
-			return t;
-		else if (t == 0)
-			return -ETIME;
-		return 0;
-	}
-}
-EXPORT_SYMBOL_GPL(apple_rtkit_send_message_wait);
-
 int apple_rtkit_poll(struct apple_rtkit *rtk)
 {
-	return mbox_client_peek_data(rtk->mbox_chan);
+	return apple_mbox_poll(rtk->mbox);
 }
 EXPORT_SYMBOL_GPL(apple_rtkit_poll);
 
@@ -697,20 +629,6 @@ int apple_rtkit_start_ep(struct apple_rtkit *rtk, u8 endpoint)
 }
 EXPORT_SYMBOL_GPL(apple_rtkit_start_ep);
 
-static int apple_rtkit_request_mbox_chan(struct apple_rtkit *rtk)
-{
-	if (rtk->mbox_name)
-		rtk->mbox_chan = mbox_request_channel_byname(&rtk->mbox_cl,
-							     rtk->mbox_name);
-	else
-		rtk->mbox_chan =
-			mbox_request_channel(&rtk->mbox_cl, rtk->mbox_idx);
-
-	if (IS_ERR(rtk->mbox_chan))
-		return PTR_ERR(rtk->mbox_chan);
-	return 0;
-}
-
 struct apple_rtkit *apple_rtkit_init(struct device *dev, void *cookie,
 					    const char *mbox_name, int mbox_idx,
 					    const struct apple_rtkit_ops *ops)
@@ -736,13 +654,18 @@ struct apple_rtkit *apple_rtkit_init(struct device *dev, void *cookie,
 	bitmap_zero(rtk->endpoints, APPLE_RTKIT_MAX_ENDPOINTS);
 	set_bit(APPLE_RTKIT_EP_MGMT, rtk->endpoints);
 
-	rtk->mbox_name = mbox_name;
-	rtk->mbox_idx = mbox_idx;
-	rtk->mbox_cl.dev = dev;
-	rtk->mbox_cl.tx_block = false;
-	rtk->mbox_cl.knows_txdone = false;
-	rtk->mbox_cl.rx_callback = &apple_rtkit_rx;
-	rtk->mbox_cl.tx_done = &apple_rtkit_tx_done;
+	if (mbox_name)
+		rtk->mbox = apple_mbox_get_byname(dev, mbox_name);
+	else
+		rtk->mbox = apple_mbox_get(dev, mbox_idx);
+
+	if (IS_ERR(rtk->mbox)) {
+		ret = PTR_ERR(rtk->mbox);
+		goto free_rtk;
+	}
+
+	rtk->mbox->rx = apple_rtkit_rx;
+	rtk->mbox->cookie = rtk;
 
 	rtk->wq = alloc_ordered_workqueue("rtkit-%s", WQ_MEM_RECLAIM,
 					  dev_name(rtk->dev));
@@ -751,7 +674,7 @@ struct apple_rtkit *apple_rtkit_init(struct device *dev, void *cookie,
 		goto free_rtk;
 	}
 
-	ret = apple_rtkit_request_mbox_chan(rtk);
+	ret = apple_mbox_start(rtk->mbox);
 	if (ret)
 		goto destroy_wq;
 
@@ -782,7 +705,7 @@ static int apple_rtkit_wait_for_completion(struct completion *c)
 int apple_rtkit_reinit(struct apple_rtkit *rtk)
 {
 	/* make sure we don't handle any messages while reinitializing */
-	mbox_free_channel(rtk->mbox_chan);
+	apple_mbox_stop(rtk->mbox);
 	flush_workqueue(rtk->wq);
 
 	apple_rtkit_free_buffer(rtk, &rtk->ioreport_buffer);
@@ -806,7 +729,7 @@ int apple_rtkit_reinit(struct apple_rtkit *rtk)
 	rtk->iop_power_state = APPLE_RTKIT_PWR_STATE_OFF;
 	rtk->ap_power_state = APPLE_RTKIT_PWR_STATE_OFF;
 
-	return apple_rtkit_request_mbox_chan(rtk);
+	return apple_mbox_start(rtk->mbox);
 }
 EXPORT_SYMBOL_GPL(apple_rtkit_reinit);
 
@@ -962,7 +885,7 @@ EXPORT_SYMBOL_GPL(apple_rtkit_wake);
 
 void apple_rtkit_free(struct apple_rtkit *rtk)
 {
-	mbox_free_channel(rtk->mbox_chan);
+	apple_mbox_stop(rtk->mbox);
 	destroy_workqueue(rtk->wq);
 
 	apple_rtkit_free_buffer(rtk, &rtk->ioreport_buffer);