16 files changed, 7662 insertions, 0 deletions
diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
new file mode 100644
index 000000000..d3795860f
--- /dev/null
+++ b/drivers/rpmsg/Kconfig
@@ -0,0 +1,84 @@
+# SPDX-License-Identifier: GPL-2.0
+
+menu "Rpmsg drivers"
+
+# RPMSG always gets selected by whoever wants it
+config RPMSG
+	tristate
+
+config RPMSG_CHAR
+	tristate "RPMSG device interface"
+	depends on RPMSG
+	depends on NET
+	help
+	  Say Y here to export rpmsg endpoints as device files, usually found
+	  in /dev. They make it possible for user-space programs to send and
+	  receive rpmsg packets.
+
+config RPMSG_CTRL
+	tristate "RPMSG control interface"
+	depends on RPMSG && ( RPMSG_CHAR || RPMSG_CHAR=n )
+	help
+	  Say Y here to enable the support of the /dev/rpmsg_ctrlX API. This API
+	  allows user-space programs to create endpoints with specific service name,
+	  source and destination addresses.
+
+config RPMSG_NS
+	tristate "RPMSG name service announcement"
+	depends on RPMSG
+	help
+	  Say Y here to enable the support of the name service announcement
+	  channel that probes the associated RPMsg device on remote endpoint
+	  service announcement.
+
+config RPMSG_MTK_SCP
+	tristate "MediaTek SCP"
+	depends on MTK_SCP
+	select RPMSG
+	help
+	  Say y here to enable support providing communication channels to
+	  remote processors in MediaTek platforms.
+	  This use IPI and IPC to communicate with remote processors.
+
+config RPMSG_QCOM_GLINK
+	tristate
+	select RPMSG
+
+config RPMSG_QCOM_GLINK_RPM
+	tristate "Qualcomm RPM Glink driver"
+	select RPMSG_QCOM_GLINK
+	depends on HAS_IOMEM
+	depends on MAILBOX
+	help
+	  Say y here to enable support for the GLINK RPM communication driver,
+	  which serves as a channel for communication with the RPM in GLINK
+	  enabled systems.
+
+config RPMSG_QCOM_GLINK_SMEM
+	tristate "Qualcomm SMEM Glink driver"
+	select RPMSG_QCOM_GLINK
+	depends on MAILBOX
+	depends on QCOM_SMEM
+	help
+	  Say y here to enable support for the GLINK SMEM communication driver,
+	  which provides support for using the GLINK communication protocol
+	  over SMEM.
+
+config RPMSG_QCOM_SMD
+	tristate "Qualcomm Shared Memory Driver (SMD)"
+	depends on MAILBOX
+	depends on QCOM_SMEM
+	select RPMSG
+	help
+	  Say y here to enable support for the Qualcomm Shared Memory Driver
+	  providing communication channels to remote processors in Qualcomm
+	  platforms.
+
+config RPMSG_VIRTIO
+	tristate "Virtio RPMSG bus driver"
+	depends on HAS_DMA
+	select RPMSG
+	select RPMSG_NS
+	select VIRTIO
+
+endmenu
diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
new file mode 100644
index 000000000..58e3b382e
--- /dev/null
+++ b/drivers/rpmsg/Makefile
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_RPMSG)		+= rpmsg_core.o
+obj-$(CONFIG_RPMSG_CHAR)	+= rpmsg_char.o
+obj-$(CONFIG_RPMSG_CTRL)	+= rpmsg_ctrl.o
+obj-$(CONFIG_RPMSG_NS)		+= rpmsg_ns.o
+obj-$(CONFIG_RPMSG_MTK_SCP)	+= mtk_rpmsg.o
+qcom_glink-objs			:= qcom_glink_native.o qcom_glink_ssr.o
+obj-$(CONFIG_RPMSG_QCOM_GLINK) += qcom_glink.o
+obj-$(CONFIG_RPMSG_QCOM_GLINK_RPM) += qcom_glink_rpm.o
+obj-$(CONFIG_RPMSG_QCOM_GLINK_SMEM) += qcom_glink_smem.o
+obj-$(CONFIG_RPMSG_QCOM_SMD)	+= qcom_smd.o
+obj-$(CONFIG_RPMSG_VIRTIO)	+= virtio_rpmsg_bus.o
diff --git a/drivers/rpmsg/mtk_rpmsg.c b/drivers/rpmsg/mtk_rpmsg.c
new file mode 100644
index 000000000..d1213c33d
--- /dev/null
+++ b/drivers/rpmsg/mtk_rpmsg.c
@@ -0,0 +1,410 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright 2019 Google LLC.
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/remoteproc.h>
+#include <linux/rpmsg/mtk_rpmsg.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#include "rpmsg_internal.h"
+
+struct mtk_rpmsg_rproc_subdev {
+	struct platform_device *pdev;
+	struct mtk_rpmsg_info *info;
+	struct rpmsg_endpoint *ns_ept;
+	struct rproc_subdev subdev;
+
+	struct work_struct register_work;
+	struct list_head channels;
+	struct mutex channels_lock;
+};
+
+#define to_mtk_subdev(d) container_of(d, struct mtk_rpmsg_rproc_subdev, subdev)
+
+struct mtk_rpmsg_channel_info {
+	struct rpmsg_channel_info info;
+	bool registered;
+	struct list_head list;
+};
+
+/**
+ * struct rpmsg_ns_msg - dynamic name service announcement message
+ * @name: name of remote service that is published
+ * @addr: address of remote service that is published
+ *
+ * This message is sent across to publish a new service. When we receive these
+ * messages, an appropriate rpmsg channel (i.e device) is created. In turn, the
+ * ->probe() handler of the appropriate rpmsg driver will be invoked
+ *  (if/as-soon-as one is registered).
+ */
+struct rpmsg_ns_msg {
+	char name[RPMSG_NAME_SIZE];
+	u32 addr;
+} __packed;
+
+struct mtk_rpmsg_device {
+	struct rpmsg_device rpdev;
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev;
+};
+
+struct mtk_rpmsg_endpoint {
+	struct rpmsg_endpoint ept;
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev;
+};
+
+#define to_mtk_rpmsg_device(r) container_of(r, struct mtk_rpmsg_device, rpdev)
+#define to_mtk_rpmsg_endpoint(r) container_of(r, struct mtk_rpmsg_endpoint, ept)
+
+static const struct rpmsg_endpoint_ops mtk_rpmsg_endpoint_ops;
+
+static void __mtk_ept_release(struct kref *kref)
+{
+	struct rpmsg_endpoint *ept = container_of(kref, struct rpmsg_endpoint,
+						  refcount);
+	kfree(to_mtk_rpmsg_endpoint(ept));
+}
+
+static void mtk_rpmsg_ipi_handler(void *data, unsigned int len, void *priv)
+{
+	struct mtk_rpmsg_endpoint *mept = priv;
+	struct rpmsg_endpoint *ept = &mept->ept;
+	int ret;
+
+	ret = (*ept->cb)(ept->rpdev, data, len, ept->priv, ept->addr);
+	if (ret)
+		dev_warn(&ept->rpdev->dev, "rpmsg handler return error = %d",
+			 ret);
+}
+
+static struct rpmsg_endpoint *
+__mtk_create_ept(struct mtk_rpmsg_rproc_subdev *mtk_subdev,
+		 struct rpmsg_device *rpdev, rpmsg_rx_cb_t cb, void *priv,
+		 u32 id)
+{
+	struct mtk_rpmsg_endpoint *mept;
+	struct rpmsg_endpoint *ept;
+	struct platform_device *pdev = mtk_subdev->pdev;
+	int ret;
+
+	mept = kzalloc(sizeof(*mept), GFP_KERNEL);
+	if (!mept)
+		return NULL;
+	mept->mtk_subdev = mtk_subdev;
+
+	ept = &mept->ept;
+	kref_init(&ept->refcount);
+
+	ept->rpdev = rpdev;
+	ept->cb = cb;
+	ept->priv = priv;
+	ept->ops = &mtk_rpmsg_endpoint_ops;
+	ept->addr = id;
+
+	ret = mtk_subdev->info->register_ipi(pdev, id, mtk_rpmsg_ipi_handler,
+					     mept);
+	if (ret) {
+		dev_err(&pdev->dev, "IPI register failed, id = %d", id);
+		kref_put(&ept->refcount, __mtk_ept_release);
+		return NULL;
+	}
+
+	return ept;
+}
+
+static struct rpmsg_endpoint *
+mtk_rpmsg_create_ept(struct rpmsg_device *rpdev, rpmsg_rx_cb_t cb, void *priv,
+		     struct rpmsg_channel_info chinfo)
+{
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev =
+		to_mtk_rpmsg_device(rpdev)->mtk_subdev;
+
+	return __mtk_create_ept(mtk_subdev, rpdev, cb, priv, chinfo.src);
+}
+
+static void mtk_rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
+{
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev =
+		to_mtk_rpmsg_endpoint(ept)->mtk_subdev;
+
+	mtk_subdev->info->unregister_ipi(mtk_subdev->pdev, ept->addr);
+	kref_put(&ept->refcount, __mtk_ept_release);
+}
+
+static int mtk_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev =
+		to_mtk_rpmsg_endpoint(ept)->mtk_subdev;
+
+	return mtk_subdev->info->send_ipi(mtk_subdev->pdev, ept->addr, data,
+					  len, 0);
+}
+
+static int mtk_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev =
+		to_mtk_rpmsg_endpoint(ept)->mtk_subdev;
+
+	/*
+	 * TODO: This currently is same as mtk_rpmsg_send, and wait until SCP
+	 * received the last command.
+	 */
+	return mtk_subdev->info->send_ipi(mtk_subdev->pdev, ept->addr, data,
+					  len, 0);
+}
+
+static const struct rpmsg_endpoint_ops mtk_rpmsg_endpoint_ops = {
+	.destroy_ept = mtk_rpmsg_destroy_ept,
+	.send = mtk_rpmsg_send,
+	.trysend = mtk_rpmsg_trysend,
+};
+
+static void mtk_rpmsg_release_device(struct device *dev)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+	struct mtk_rpmsg_device *mdev = to_mtk_rpmsg_device(rpdev);
+
+	kfree(mdev);
+}
+
+static const struct rpmsg_device_ops mtk_rpmsg_device_ops = {
+	.create_ept = mtk_rpmsg_create_ept,
+};
+
+static struct device_node *
+mtk_rpmsg_match_device_subnode(struct device_node *node, const char *channel)
+{
+	struct device_node *child;
+	const char *name;
+	int ret;
+
+	for_each_available_child_of_node(node, child) {
+		ret = of_property_read_string(child, "mediatek,rpmsg-name", &name);
+		if (ret)
+			continue;
+
+		if (strcmp(name, channel) == 0)
+			return child;
+	}
+
+	return NULL;
+}
+
+static int mtk_rpmsg_register_device(struct mtk_rpmsg_rproc_subdev *mtk_subdev,
+				     struct rpmsg_channel_info *info)
+{
+	struct rpmsg_device *rpdev;
+	struct mtk_rpmsg_device *mdev;
+	struct platform_device *pdev = mtk_subdev->pdev;
+
+	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
+	if (!mdev)
+		return -ENOMEM;
+
+	mdev->mtk_subdev = mtk_subdev;
+
+	rpdev = &mdev->rpdev;
+	rpdev->ops = &mtk_rpmsg_device_ops;
+	rpdev->src = info->src;
+	rpdev->dst = info->dst;
+	strscpy(rpdev->id.name, info->name, RPMSG_NAME_SIZE);
+
+	rpdev->dev.of_node =
+		mtk_rpmsg_match_device_subnode(pdev->dev.of_node, info->name);
+	rpdev->dev.parent = &pdev->dev;
+	rpdev->dev.release = mtk_rpmsg_release_device;
+
+	return rpmsg_register_device(rpdev);
+}
+
+static void mtk_register_device_work_function(struct work_struct *register_work)
+{
+	struct mtk_rpmsg_rproc_subdev *subdev = container_of(
+		register_work, struct mtk_rpmsg_rproc_subdev, register_work);
+	struct platform_device *pdev = subdev->pdev;
+	struct mtk_rpmsg_channel_info *info;
+	int ret;
+
+	mutex_lock(&subdev->channels_lock);
+	list_for_each_entry(info, &subdev->channels, list) {
+		if (info->registered)
+			continue;
+
+		mutex_unlock(&subdev->channels_lock);
+		ret = mtk_rpmsg_register_device(subdev, &info->info);
+		mutex_lock(&subdev->channels_lock);
+		if (ret) {
+			dev_err(&pdev->dev, "Can't create rpmsg_device\n");
+			continue;
+		}
+
+		info->registered = true;
+	}
+	mutex_unlock(&subdev->channels_lock);
+}
+
+static int mtk_rpmsg_create_device(struct mtk_rpmsg_rproc_subdev *mtk_subdev,
+				   char *name, u32 addr)
+{
+	struct mtk_rpmsg_channel_info *info;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	strscpy(info->info.name, name, RPMSG_NAME_SIZE);
+	info->info.src = addr;
+	info->info.dst = RPMSG_ADDR_ANY;
+	mutex_lock(&mtk_subdev->channels_lock);
+	list_add(&info->list, &mtk_subdev->channels);
+	mutex_unlock(&mtk_subdev->channels_lock);
+
+	schedule_work(&mtk_subdev->register_work);
+	return 0;
+}
+
+static int mtk_rpmsg_ns_cb(struct rpmsg_device *rpdev, void *data, int len,
+			   void *priv, u32 src)
+{
+	struct rpmsg_ns_msg *msg = data;
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev = priv;
+	struct device *dev = &mtk_subdev->pdev->dev;
+
+	int ret;
+
+	if (len != sizeof(*msg)) {
+		dev_err(dev, "malformed ns msg (%d)\n", len);
+		return -EINVAL;
+	}
+
+	/*
+	 * the name service ept does _not_ belong to a real rpmsg channel,
+	 * and is handled by the rpmsg bus itself.
+	 * for sanity reasons, make sure a valid rpdev has _not_ sneaked
+	 * in somehow.
+	 */
+	if (rpdev) {
+		dev_err(dev, "anomaly: ns ept has an rpdev handle\n");
+		return -EINVAL;
+	}
+
+	/* don't trust the remote processor for null terminating the name */
+	msg->name[RPMSG_NAME_SIZE - 1] = '\0';
+
+	dev_info(dev, "creating channel %s addr 0x%x\n", msg->name, msg->addr);
+
+	ret = mtk_rpmsg_create_device(mtk_subdev, msg->name, msg->addr);
+	if (ret) {
+		dev_err(dev, "create rpmsg device failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int mtk_rpmsg_prepare(struct rproc_subdev *subdev)
+{
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev = to_mtk_subdev(subdev);
+
+	/* a dedicated endpoint handles the name service msgs */
+	if (mtk_subdev->info->ns_ipi_id >= 0) {
+		mtk_subdev->ns_ept =
+			__mtk_create_ept(mtk_subdev, NULL, mtk_rpmsg_ns_cb,
+					 mtk_subdev,
+					 mtk_subdev->info->ns_ipi_id);
+		if (!mtk_subdev->ns_ept) {
+			dev_err(&mtk_subdev->pdev->dev,
+				"failed to create name service endpoint\n");
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
+static void mtk_rpmsg_unprepare(struct rproc_subdev *subdev)
+{
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev = to_mtk_subdev(subdev);
+
+	if (mtk_subdev->ns_ept) {
+		mtk_rpmsg_destroy_ept(mtk_subdev->ns_ept);
+		mtk_subdev->ns_ept = NULL;
+	}
+}
+
+static void mtk_rpmsg_stop(struct rproc_subdev *subdev, bool crashed)
+{
+	struct mtk_rpmsg_channel_info *info, *next;
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev = to_mtk_subdev(subdev);
+	struct device *dev = &mtk_subdev->pdev->dev;
+
+	/*
+	 * Destroy the name service endpoint here, to avoid new channel being
+	 * created after the rpmsg_unregister_device loop below.
+	 */
+	if (mtk_subdev->ns_ept) {
+		mtk_rpmsg_destroy_ept(mtk_subdev->ns_ept);
+		mtk_subdev->ns_ept = NULL;
+	}
+
+	cancel_work_sync(&mtk_subdev->register_work);
+
+	mutex_lock(&mtk_subdev->channels_lock);
+	list_for_each_entry(info, &mtk_subdev->channels, list) {
+		if (!info->registered)
+			continue;
+		if (rpmsg_unregister_device(dev, &info->info)) {
+			dev_warn(
+				dev,
+				"rpmsg_unregister_device failed for %s.%d.%d\n",
+				info->info.name, info->info.src,
+				info->info.dst);
+		}
+	}
+
+	list_for_each_entry_safe(info, next,
+				 &mtk_subdev->channels, list) {
+		list_del(&info->list);
+		kfree(info);
+	}
+	mutex_unlock(&mtk_subdev->channels_lock);
+}
+
+struct rproc_subdev *
+mtk_rpmsg_create_rproc_subdev(struct platform_device *pdev,
+			      struct mtk_rpmsg_info *info)
+{
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev;
+
+	mtk_subdev = kzalloc(sizeof(*mtk_subdev), GFP_KERNEL);
+	if (!mtk_subdev)
+		return NULL;
+
+	mtk_subdev->pdev = pdev;
+	mtk_subdev->subdev.prepare = mtk_rpmsg_prepare;
+	mtk_subdev->subdev.stop = mtk_rpmsg_stop;
+	mtk_subdev->subdev.unprepare = mtk_rpmsg_unprepare;
+	mtk_subdev->info = info;
+	INIT_LIST_HEAD(&mtk_subdev->channels);
+	INIT_WORK(&mtk_subdev->register_work,
+		  mtk_register_device_work_function);
+	mutex_init(&mtk_subdev->channels_lock);
+
+	return &mtk_subdev->subdev;
+}
+EXPORT_SYMBOL_GPL(mtk_rpmsg_create_rproc_subdev);
+
+void mtk_rpmsg_destroy_rproc_subdev(struct rproc_subdev *subdev)
+{
+	struct mtk_rpmsg_rproc_subdev *mtk_subdev = to_mtk_subdev(subdev);
+
+	kfree(mtk_subdev);
+}
+EXPORT_SYMBOL_GPL(mtk_rpmsg_destroy_rproc_subdev);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("MediaTek scp rpmsg driver");
diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
new file mode 100644
index 000000000..cb8f65c1d
--- /dev/null
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -0,0 +1,1839 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2016-2017, Linaro Ltd
+ */
+
+#include <linux/idr.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/list.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/rpmsg.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+#include <linux/mailbox_client.h>
+
+#include "rpmsg_internal.h"
+#include "qcom_glink_native.h"
+
+#define GLINK_NAME_SIZE		32
+#define GLINK_VERSION_1		1
+
+#define RPM_GLINK_CID_MIN	1
+#define RPM_GLINK_CID_MAX	65536
+
+struct glink_msg {
+	__le16 cmd;
+	__le16 param1;
+	__le32 param2;
+	u8 data[];
+} __packed;
+
+/**
+ * struct glink_defer_cmd - deferred incoming control message
+ * @node:	list node
+ * @msg:	message header
+ * @data:	payload of the message
+ *
+ * Copy of a received control message, to be added to @rx_queue and processed
+ * by @rx_work of @qcom_glink.
+ */
+struct glink_defer_cmd {
+	struct list_head node;
+
+	struct glink_msg msg;
+	u8 data[];
+};
+
+/**
+ * struct glink_core_rx_intent - RX intent
+ * RX intent
+ *
+ * @data: pointer to the data (may be NULL for zero-copy)
+ * @id: remote or local intent ID
+ * @size: size of the original intent (do not modify)
+ * @reuse: To mark if the intent can be reused after first use
+ * @in_use: To mark if intent is already in use for the channel
+ * @offset: next write offset (initially 0)
+ * @node:	list node
+ */
+struct glink_core_rx_intent {
+	void *data;
+	u32 id;
+	size_t size;
+	bool reuse;
+	bool in_use;
+	u32 offset;
+
+	struct list_head node;
+};
+
+/**
+ * struct qcom_glink - driver context, relates to one remote subsystem
+ * @dev:	reference to the associated struct device
+ * @mbox_client: mailbox client
+ * @mbox_chan:  mailbox channel
+ * @rx_pipe:	pipe object for receive FIFO
+ * @tx_pipe:	pipe object for transmit FIFO
+ * @irq:	IRQ for signaling incoming events
+ * @rx_work:	worker for handling received control messages
+ * @rx_lock:	protects the @rx_queue
+ * @rx_queue:	queue of received control messages to be processed in @rx_work
+ * @tx_lock:	synchronizes operations on the tx fifo
+ * @idr_lock:	synchronizes @lcids and @rcids modifications
+ * @lcids:	idr of all channels with a known local channel id
+ * @rcids:	idr of all channels with a known remote channel id
+ * @features:	remote features
+ * @intentless:	flag to indicate that there is no intent
+ * @tx_avail_notify: Waitqueue for pending tx tasks
+ * @sent_read_notify: flag to check cmd sent or not
+ */
+struct qcom_glink {
+	struct device *dev;
+
+	struct mbox_client mbox_client;
+	struct mbox_chan *mbox_chan;
+
+	struct qcom_glink_pipe *rx_pipe;
+	struct qcom_glink_pipe *tx_pipe;
+
+	int irq;
+
+	struct work_struct rx_work;
+	spinlock_t rx_lock;
+	struct list_head rx_queue;
+
+	spinlock_t tx_lock;
+
+	spinlock_t idr_lock;
+	struct idr lcids;
+	struct idr rcids;
+	unsigned long features;
+
+	bool intentless;
+	wait_queue_head_t tx_avail_notify;
+	bool sent_read_notify;
+};
+
+enum {
+	GLINK_STATE_CLOSED,
+	GLINK_STATE_OPENING,
+	GLINK_STATE_OPEN,
+	GLINK_STATE_CLOSING,
+};
+
+/**
+ * struct glink_channel - internal representation of a channel
+ * @rpdev:	rpdev reference, only used for primary endpoints
+ * @ept:	rpmsg endpoint this channel is associated with
+ * @glink:	qcom_glink context handle
+ * @refcount:	refcount for the channel object
+ * @recv_lock:	guard for @ept.cb
+ * @name:	unique channel name/identifier
+ * @lcid:	channel id, in local space
+ * @rcid:	channel id, in remote space
+ * @intent_lock: lock for protection of @liids, @riids
+ * @liids:	idr of all local intents
+ * @riids:	idr of all remote intents
+ * @intent_work: worker responsible for transmitting rx_done packets
+ * @done_intents: list of intents that needs to be announced rx_done
+ * @buf:	receive buffer, for gathering fragments
+ * @buf_offset:	write offset in @buf
+ * @buf_size:	size of current @buf
+ * @open_ack:	completed once remote has acked the open-request
+ * @open_req:	completed once open-request has been received
+ * @intent_req_lock: Synchronises multiple intent requests
+ * @intent_req_result: Result of intent request
+ * @intent_req_comp: Completion for intent_req signalling
+ */
+struct glink_channel {
+	struct rpmsg_endpoint ept;
+
+	struct rpmsg_device *rpdev;
+	struct qcom_glink *glink;
+
+	struct kref refcount;
+
+	spinlock_t recv_lock;
+
+	char *name;
+	unsigned int lcid;
+	unsigned int rcid;
+
+	spinlock_t intent_lock;
+	struct idr liids;
+	struct idr riids;
+	struct work_struct intent_work;
+	struct list_head done_intents;
+
+	struct glink_core_rx_intent *buf;
+	int buf_offset;
+	int buf_size;
+
+	struct completion open_ack;
+	struct completion open_req;
+
+	struct mutex intent_req_lock;
+	bool intent_req_result;
+	struct completion intent_req_comp;
+};
+
+#define to_glink_channel(_ept) container_of(_ept, struct glink_channel, ept)
+
+static const struct rpmsg_endpoint_ops glink_endpoint_ops;
+
+#define RPM_CMD_VERSION			0
+#define RPM_CMD_VERSION_ACK		1
+#define RPM_CMD_OPEN			2
+#define RPM_CMD_CLOSE			3
+#define RPM_CMD_OPEN_ACK		4
+#define RPM_CMD_INTENT			5
+#define RPM_CMD_RX_DONE			6
+#define RPM_CMD_RX_INTENT_REQ		7
+#define RPM_CMD_RX_INTENT_REQ_ACK	8
+#define RPM_CMD_TX_DATA			9
+#define RPM_CMD_CLOSE_ACK		11
+#define RPM_CMD_TX_DATA_CONT		12
+#define RPM_CMD_READ_NOTIF		13
+#define RPM_CMD_RX_DONE_W_REUSE		14
+
+#define GLINK_FEATURE_INTENTLESS	BIT(1)
+
+static void qcom_glink_rx_done_work(struct work_struct *work);
+
+static struct glink_channel *qcom_glink_alloc_channel(struct qcom_glink *glink,
+						      const char *name)
+{
+	struct glink_channel *channel;
+
+	channel = kzalloc(sizeof(*channel), GFP_KERNEL);
+	if (!channel)
+		return ERR_PTR(-ENOMEM);
+
+	/* Setup glink internal glink_channel data */
+	spin_lock_init(&channel->recv_lock);
+	spin_lock_init(&channel->intent_lock);
+	mutex_init(&channel->intent_req_lock);
+
+	channel->glink = glink;
+	channel->name = kstrdup(name, GFP_KERNEL);
+	if (!channel->name) {
+		kfree(channel);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	init_completion(&channel->open_req);
+	init_completion(&channel->open_ack);
+	init_completion(&channel->intent_req_comp);
+
+	INIT_LIST_HEAD(&channel->done_intents);
+	INIT_WORK(&channel->intent_work, qcom_glink_rx_done_work);
+
+	idr_init(&channel->liids);
+	idr_init(&channel->riids);
+	kref_init(&channel->refcount);
+
+	return channel;
+}
+
+static void qcom_glink_channel_release(struct kref *ref)
+{
+	struct glink_channel *channel = container_of(ref, struct glink_channel,
+						     refcount);
+	struct glink_core_rx_intent *intent;
+	struct glink_core_rx_intent *tmp;
+	unsigned long flags;
+	int iid;
+
+	/* cancel pending rx_done work */
+	cancel_work_sync(&channel->intent_work);
+
+	spin_lock_irqsave(&channel->intent_lock, flags);
+	/* Free all non-reuse intents pending rx_done work */
+	list_for_each_entry_safe(intent, tmp, &channel->done_intents, node) {
+		if (!intent->reuse) {
+			kfree(intent->data);
+			kfree(intent);
+		}
+	}
+
+	idr_for_each_entry(&channel->liids, tmp, iid) {
+		kfree(tmp->data);
+		kfree(tmp);
+	}
+	idr_destroy(&channel->liids);
+
+	idr_for_each_entry(&channel->riids, tmp, iid)
+		kfree(tmp);
+	idr_destroy(&channel->riids);
+	spin_unlock_irqrestore(&channel->intent_lock, flags);
+
+	kfree(channel->name);
+	kfree(channel);
+}
+
+static size_t qcom_glink_rx_avail(struct qcom_glink *glink)
+{
+	return glink->rx_pipe->avail(glink->rx_pipe);
+}
+
+static void qcom_glink_rx_peak(struct qcom_glink *glink,
+			       void *data, unsigned int offset, size_t count)
+{
+	glink->rx_pipe->peak(glink->rx_pipe, data, offset, count);
+}
+
+static void qcom_glink_rx_advance(struct qcom_glink *glink, size_t count)
+{
+	glink->rx_pipe->advance(glink->rx_pipe, count);
+}
+
+static size_t qcom_glink_tx_avail(struct qcom_glink *glink)
+{
+	return glink->tx_pipe->avail(glink->tx_pipe);
+}
+
+static void qcom_glink_tx_write(struct qcom_glink *glink,
+				const void *hdr, size_t hlen,
+				const void *data, size_t dlen)
+{
+	glink->tx_pipe->write(glink->tx_pipe, hdr, hlen, data, dlen);
+}
+
+static void qcom_glink_send_read_notify(struct qcom_glink *glink)
+{
+	struct glink_msg msg;
+
+	msg.cmd = cpu_to_le16(RPM_CMD_READ_NOTIF);
+	msg.param1 = 0;
+	msg.param2 = 0;
+
+	qcom_glink_tx_write(glink, &msg, sizeof(msg), NULL, 0);
+
+	mbox_send_message(glink->mbox_chan, NULL);
+	mbox_client_txdone(glink->mbox_chan, 0);
+}
+
+static int qcom_glink_tx(struct qcom_glink *glink,
+			 const void *hdr, size_t hlen,
+			 const void *data, size_t dlen, bool wait)
+{
+	unsigned int tlen = hlen + dlen;
+	unsigned long flags;
+	int ret = 0;
+
+	/* Reject packets that are too big */
+	if (tlen >= glink->tx_pipe->length)
+		return -EINVAL;
+
+	spin_lock_irqsave(&glink->tx_lock, flags);
+
+	while (qcom_glink_tx_avail(glink) < tlen) {
+		if (!wait) {
+			ret = -EAGAIN;
+			goto out;
+		}
+
+		if (!glink->sent_read_notify) {
+			glink->sent_read_notify = true;
+			qcom_glink_send_read_notify(glink);
+		}
+
+		/* Wait without holding the tx_lock */
+		spin_unlock_irqrestore(&glink->tx_lock, flags);
+
+		wait_event_timeout(glink->tx_avail_notify,
+				   qcom_glink_tx_avail(glink) >= tlen, 10 * HZ);
+
+		spin_lock_irqsave(&glink->tx_lock, flags);
+
+		if (qcom_glink_tx_avail(glink) >= tlen)
+			glink->sent_read_notify = false;
+	}
+
+	qcom_glink_tx_write(glink, hdr, hlen, data, dlen);
+
+	mbox_send_message(glink->mbox_chan, NULL);
+	mbox_client_txdone(glink->mbox_chan, 0);
+
+out:
+	spin_unlock_irqrestore(&glink->tx_lock, flags);
+
+	return ret;
+}
+
+static int qcom_glink_send_version(struct qcom_glink *glink)
+{
+	struct glink_msg msg;
+
+	msg.cmd = cpu_to_le16(RPM_CMD_VERSION);
+	msg.param1 = cpu_to_le16(GLINK_VERSION_1);
+	msg.param2 = cpu_to_le32(glink->features);
+
+	return qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
+}
+
+static void qcom_glink_send_version_ack(struct qcom_glink *glink)
+{
+	struct glink_msg msg;
+
+	msg.cmd = cpu_to_le16(RPM_CMD_VERSION_ACK);
+	msg.param1 = cpu_to_le16(GLINK_VERSION_1);
+	msg.param2 = cpu_to_le32(glink->features);
+
+	qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
+}
+
+static void qcom_glink_send_open_ack(struct qcom_glink *glink,
+				     struct glink_channel *channel)
+{
+	struct glink_msg msg;
+
+	msg.cmd = cpu_to_le16(RPM_CMD_OPEN_ACK);
+	msg.param1 = cpu_to_le16(channel->rcid);
+	msg.param2 = cpu_to_le32(0);
+
+	qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
+}
+
+static void qcom_glink_handle_intent_req_ack(struct qcom_glink *glink,
+					     unsigned int cid, bool granted)
+{
+	struct glink_channel *channel;
+	unsigned long flags;
+
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	channel = idr_find(&glink->rcids, cid);
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+	if (!channel) {
+		dev_err(glink->dev, "unable to find channel\n");
+		return;
+	}
+
+	channel->intent_req_result = granted;
+	complete(&channel->intent_req_comp);
+}
+
+/**
+ * qcom_glink_send_open_req() - send a RPM_CMD_OPEN request to the remote
+ * @glink: Ptr to the glink edge
+ * @channel: Ptr to the channel that the open req is sent
+ *
+ * Allocates a local channel id and sends a RPM_CMD_OPEN message to the remote.
+ * Will return with refcount held, regardless of outcome.
+ *
+ * Return: 0 on success, negative errno otherwise.
+ */
+static int qcom_glink_send_open_req(struct qcom_glink *glink,
+				    struct glink_channel *channel)
+{
+	struct {
+		struct glink_msg msg;
+		u8 name[GLINK_NAME_SIZE];
+	} __packed req;
+	int name_len = strlen(channel->name) + 1;
+	int req_len = ALIGN(sizeof(req.msg) + name_len, 8);
+	int ret;
+	unsigned long flags;
+
+	kref_get(&channel->refcount);
+
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	ret = idr_alloc_cyclic(&glink->lcids, channel,
+			       RPM_GLINK_CID_MIN, RPM_GLINK_CID_MAX,
+			       GFP_ATOMIC);
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+	if (ret < 0)
+		return ret;
+
+	channel->lcid = ret;
+
+	req.msg.cmd = cpu_to_le16(RPM_CMD_OPEN);
+	req.msg.param1 = cpu_to_le16(channel->lcid);
+	req.msg.param2 = cpu_to_le32(name_len);
+	strcpy(req.name, channel->name);
+
+	ret = qcom_glink_tx(glink, &req, req_len, NULL, 0, true);
+	if (ret)
+		goto remove_idr;
+
+	return 0;
+
+remove_idr:
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	idr_remove(&glink->lcids, channel->lcid);
+	channel->lcid = 0;
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+
+	return ret;
+}
+
+static void qcom_glink_send_close_req(struct qcom_glink *glink,
+				      struct glink_channel *channel)
+{
+	struct glink_msg req;
+
+	req.cmd = cpu_to_le16(RPM_CMD_CLOSE);
+	req.param1 = cpu_to_le16(channel->lcid);
+	req.param2 = 0;
+
+	qcom_glink_tx(glink, &req, sizeof(req), NULL, 0, true);
+}
+
+static void qcom_glink_send_close_ack(struct qcom_glink *glink,
+				      unsigned int rcid)
+{
+	struct glink_msg req;
+
+	req.cmd = cpu_to_le16(RPM_CMD_CLOSE_ACK);
+	req.param1 = cpu_to_le16(rcid);
+	req.param2 = 0;
+
+	qcom_glink_tx(glink, &req, sizeof(req), NULL, 0, true);
+}
+
+static void qcom_glink_rx_done_work(struct work_struct *work)
+{
+	struct glink_channel *channel = container_of(work, struct glink_channel,
+						     intent_work);
+	struct qcom_glink *glink = channel->glink;
+	struct glink_core_rx_intent *intent, *tmp;
+	struct {
+		u16 id;
+		u16 lcid;
+		u32 liid;
+	} __packed cmd;
+
+	unsigned int cid = channel->lcid;
+	unsigned int iid;
+	bool reuse;
+	unsigned long flags;
+
+	spin_lock_irqsave(&channel->intent_lock, flags);
+	list_for_each_entry_safe(intent, tmp, &channel->done_intents, node) {
+		list_del(&intent->node);
+		spin_unlock_irqrestore(&channel->intent_lock, flags);
+		iid = intent->id;
+		reuse = intent->reuse;
+
+		cmd.id = reuse ? RPM_CMD_RX_DONE_W_REUSE : RPM_CMD_RX_DONE;
+		cmd.lcid = cid;
+		cmd.liid = iid;
+
+		qcom_glink_tx(glink, &cmd, sizeof(cmd), NULL, 0, true);
+		if (!reuse) {
+			kfree(intent->data);
+			kfree(intent);
+		}
+		spin_lock_irqsave(&channel->intent_lock, flags);
+	}
+	spin_unlock_irqrestore(&channel->intent_lock, flags);
+}
+
+static void qcom_glink_rx_done(struct qcom_glink *glink,
+			       struct glink_channel *channel,
+			       struct glink_core_rx_intent *intent)
+{
+	/* We don't send RX_DONE to intentless systems */
+	if (glink->intentless) {
+		kfree(intent->data);
+		kfree(intent);
+		return;
+	}
+
+	/* Take it off the tree of receive intents */
+	if (!intent->reuse) {
+		spin_lock(&channel->intent_lock);
+		idr_remove(&channel->liids, intent->id);
+		spin_unlock(&channel->intent_lock);
+	}
+
+	/* Schedule the sending of a rx_done indication */
+	spin_lock(&channel->intent_lock);
+	list_add_tail(&intent->node, &channel->done_intents);
+	spin_unlock(&channel->intent_lock);
+
+	schedule_work(&channel->intent_work);
+}
+
+/**
+ * qcom_glink_receive_version() - receive version/features from remote system
+ *
+ * @glink:	pointer to transport interface
+ * @version:	remote version
+ * @features:	remote features
+ *
+ * This function is called in response to a remote-initiated version/feature
+ * negotiation sequence.
+ */
+static void qcom_glink_receive_version(struct qcom_glink *glink,
+				       u32 version,
+				       u32 features)
+{
+	switch (version) {
+	case 0:
+		break;
+	case GLINK_VERSION_1:
+		glink->features &= features;
+		fallthrough;
+	default:
+		qcom_glink_send_version_ack(glink);
+		break;
+	}
+}
+
+/**
+ * qcom_glink_receive_version_ack() - receive negotiation ack from remote system
+ *
+ * @glink:	pointer to transport interface
+ * @version:	remote version response
+ * @features:	remote features response
+ *
+ * This function is called in response to a local-initiated version/feature
+ * negotiation sequence and is the counter-offer from the remote side based
+ * upon the initial version and feature set requested.
+ */
+static void qcom_glink_receive_version_ack(struct qcom_glink *glink,
+					   u32 version,
+					   u32 features)
+{
+	switch (version) {
+	case 0:
+		/* Version negotiation failed */
+		break;
+	case GLINK_VERSION_1:
+		if (features == glink->features)
+			break;
+
+		glink->features &= features;
+		fallthrough;
+	default:
+		qcom_glink_send_version(glink);
+		break;
+	}
+}
+
+/**
+ * qcom_glink_send_intent_req_ack() - convert an rx intent request ack cmd to
+ * 	wire format and transmit
+ * @glink:	The transport to transmit on.
+ * @channel:	The glink channel
+ * @granted:	The request response to encode.
+ *
+ * Return: 0 on success or standard Linux error code.
+ */
+static int qcom_glink_send_intent_req_ack(struct qcom_glink *glink,
+					  struct glink_channel *channel,
+					  bool granted)
+{
+	struct glink_msg msg;
+
+	msg.cmd = cpu_to_le16(RPM_CMD_RX_INTENT_REQ_ACK);
+	msg.param1 = cpu_to_le16(channel->lcid);
+	msg.param2 = cpu_to_le32(granted);
+
+	qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
+
+	return 0;
+}
+
+/**
+ * qcom_glink_advertise_intent - convert an rx intent cmd to wire format and
+ *			   transmit
+ * @glink:	The transport to transmit on.
+ * @channel:	The local channel
+ * @intent:	The intent to pass on to remote.
+ *
+ * Return: 0 on success or standard Linux error code.
+ */
+static int qcom_glink_advertise_intent(struct qcom_glink *glink,
+				       struct glink_channel *channel,
+				       struct glink_core_rx_intent *intent)
+{
+	struct command {
+		__le16 id;
+		__le16 lcid;
+		__le32 count;
+		__le32 size;
+		__le32 liid;
+	} __packed;
+	struct command cmd;
+
+	cmd.id = cpu_to_le16(RPM_CMD_INTENT);
+	cmd.lcid = cpu_to_le16(channel->lcid);
+	cmd.count = cpu_to_le32(1);
+	cmd.size = cpu_to_le32(intent->size);
+	cmd.liid = cpu_to_le32(intent->id);
+
+	qcom_glink_tx(glink, &cmd, sizeof(cmd), NULL, 0, true);
+
+	return 0;
+}
+
+static struct glink_core_rx_intent *
+qcom_glink_alloc_intent(struct qcom_glink *glink,
+			struct glink_channel *channel,
+			size_t size,
+			bool reuseable)
+{
+	struct glink_core_rx_intent *intent;
+	int ret;
+	unsigned long flags;
+
+	intent = kzalloc(sizeof(*intent), GFP_KERNEL);
+	if (!intent)
+		return NULL;
+
+	intent->data = kzalloc(size, GFP_KERNEL);
+	if (!intent->data)
+		goto free_intent;
+
+	spin_lock_irqsave(&channel->intent_lock, flags);
+	ret = idr_alloc_cyclic(&channel->liids, intent, 1, -1, GFP_ATOMIC);
+	if (ret < 0) {
+		spin_unlock_irqrestore(&channel->intent_lock, flags);
+		goto free_data;
+	}
+	spin_unlock_irqrestore(&channel->intent_lock, flags);
+
+	intent->id = ret;
+	intent->size = size;
+	intent->reuse = reuseable;
+
+	return intent;
+
+free_data:
+	kfree(intent->data);
+free_intent:
+	kfree(intent);
+	return NULL;
+}
+
+static void qcom_glink_handle_rx_done(struct qcom_glink *glink,
+				      u32 cid, uint32_t iid,
+				      bool reuse)
+{
+	struct glink_core_rx_intent *intent;
+	struct glink_channel *channel;
+	unsigned long flags;
+
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	channel = idr_find(&glink->rcids, cid);
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+	if (!channel) {
+		dev_err(glink->dev, "invalid channel id received\n");
+		return;
+	}
+
+	spin_lock_irqsave(&channel->intent_lock, flags);
+	intent = idr_find(&channel->riids, iid);
+
+	if (!intent) {
+		spin_unlock_irqrestore(&channel->intent_lock, flags);
+		dev_err(glink->dev, "invalid intent id received\n");
+		return;
+	}
+
+	intent->in_use = false;
+
+	if (!reuse) {
+		idr_remove(&channel->riids, intent->id);
+		kfree(intent);
+	}
+	spin_unlock_irqrestore(&channel->intent_lock, flags);
+}
+
+/**
+ * qcom_glink_handle_intent_req() - Receive a request for rx_intent
+ *					    from remote side
+ * @glink:      Pointer to the transport interface
+ * @cid:	Remote channel ID
+ * @size:	size of the intent
+ *
+ * The function searches for the local channel to which the request for
+ * rx_intent has arrived and allocates and notifies the remote back
+ */
+static void qcom_glink_handle_intent_req(struct qcom_glink *glink,
+					 u32 cid, size_t size)
+{
+	struct glink_core_rx_intent *intent;
+	struct glink_channel *channel;
+	unsigned long flags;
+
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	channel = idr_find(&glink->rcids, cid);
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+
+	if (!channel) {
+		pr_err("%s channel not found for cid %d\n", __func__, cid);
+		return;
+	}
+
+	intent = qcom_glink_alloc_intent(glink, channel, size, false);
+	if (intent)
+		qcom_glink_advertise_intent(glink, channel, intent);
+
+	qcom_glink_send_intent_req_ack(glink, channel, !!intent);
+}
+
+static int qcom_glink_rx_defer(struct qcom_glink *glink, size_t extra)
+{
+	struct glink_defer_cmd *dcmd;
+
+	extra = ALIGN(extra, 8);
+
+	if (qcom_glink_rx_avail(glink) < sizeof(struct glink_msg) + extra) {
+		dev_dbg(glink->dev, "Insufficient data in rx fifo");
+		return -ENXIO;
+	}
+
+	dcmd = kzalloc(struct_size(dcmd, data, extra), GFP_ATOMIC);
+	if (!dcmd)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&dcmd->node);
+
+	qcom_glink_rx_peak(glink, &dcmd->msg, 0, sizeof(dcmd->msg) + extra);
+
+	spin_lock(&glink->rx_lock);
+	list_add_tail(&dcmd->node, &glink->rx_queue);
+	spin_unlock(&glink->rx_lock);
+
+	schedule_work(&glink->rx_work);
+	qcom_glink_rx_advance(glink, sizeof(dcmd->msg) + extra);
+
+	return 0;
+}
+
+static int qcom_glink_rx_data(struct qcom_glink *glink, size_t avail)
+{
+	struct glink_core_rx_intent *intent;
+	struct glink_channel *channel;
+	struct {
+		struct glink_msg msg;
+		__le32 chunk_size;
+		__le32 left_size;
+	} __packed hdr;
+	unsigned int chunk_size;
+	unsigned int left_size;
+	unsigned int rcid;
+	unsigned int liid;
+	int ret = 0;
+	unsigned long flags;
+
+	if (avail < sizeof(hdr)) {
+		dev_dbg(glink->dev, "Not enough data in fifo\n");
+		return -EAGAIN;
+	}
+
+	qcom_glink_rx_peak(glink, &hdr, 0, sizeof(hdr));
+	chunk_size = le32_to_cpu(hdr.chunk_size);
+	left_size = le32_to_cpu(hdr.left_size);
+
+	if (avail < sizeof(hdr) + chunk_size) {
+		dev_dbg(glink->dev, "Payload not yet in fifo\n");
+		return -EAGAIN;
+	}
+
+	rcid = le16_to_cpu(hdr.msg.param1);
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	channel = idr_find(&glink->rcids, rcid);
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+	if (!channel) {
+		dev_dbg(glink->dev, "Data on non-existing channel\n");
+
+		/* Drop the message */
+		goto advance_rx;
+	}
+
+	if (glink->intentless) {
+		/* Might have an ongoing, fragmented, message to append */
+		if (!channel->buf) {
+			intent = kzalloc(sizeof(*intent), GFP_ATOMIC);
+			if (!intent)
+				return -ENOMEM;
+
+			intent->data = kmalloc(chunk_size + left_size,
+					       GFP_ATOMIC);
+			if (!intent->data) {
+				kfree(intent);
+				return -ENOMEM;
+			}
+
+			intent->id = 0xbabababa;
+			intent->size = chunk_size + left_size;
+			intent->offset = 0;
+
+			channel->buf = intent;
+		} else {
+			intent = channel->buf;
+		}
+	} else {
+		liid = le32_to_cpu(hdr.msg.param2);
+
+		spin_lock_irqsave(&channel->intent_lock, flags);
+		intent = idr_find(&channel->liids, liid);
+		spin_unlock_irqrestore(&channel->intent_lock, flags);
+
+		if (!intent) {
+			dev_err(glink->dev,
+				"no intent found for channel %s intent %d",
+				channel->name, liid);
+			ret = -ENOENT;
+			goto advance_rx;
+		}
+	}
+
+	if (intent->size - intent->offset < chunk_size) {
+		dev_err(glink->dev, "Insufficient space in intent\n");
+
+		/* The packet header lied, drop payload */
+		goto advance_rx;
+	}
+
+	qcom_glink_rx_peak(glink, intent->data + intent->offset,
+			   sizeof(hdr), chunk_size);
+	intent->offset += chunk_size;
+
+	/* Handle message when no fragments remain to be received */
+	if (!left_size) {
+		spin_lock(&channel->recv_lock);
+		if (channel->ept.cb) {
+			channel->ept.cb(channel->ept.rpdev,
+					intent->data,
+					intent->offset,
+					channel->ept.priv,
+					RPMSG_ADDR_ANY);
+		}
+		spin_unlock(&channel->recv_lock);
+
+		intent->offset = 0;
+		channel->buf = NULL;
+
+		qcom_glink_rx_done(glink, channel, intent);
+	}
+
+advance_rx:
+	qcom_glink_rx_advance(glink, ALIGN(sizeof(hdr) + chunk_size, 8));
+
+	return ret;
+}
+
+static void qcom_glink_handle_intent(struct qcom_glink *glink,
+				     unsigned int cid,
+				     unsigned int count,
+				     size_t avail)
+{
+	struct glink_core_rx_intent *intent;
+	struct glink_channel *channel;
+	struct intent_pair {
+		__le32 size;
+		__le32 iid;
+	};
+
+	struct {
+		struct glink_msg msg;
+		struct intent_pair intents[];
+	} __packed * msg;
+
+	const size_t msglen = struct_size(msg, intents, count);
+	int ret;
+	int i;
+	unsigned long flags;
+
+	if (avail < msglen) {
+		dev_dbg(glink->dev, "Not enough data in fifo\n");
+		return;
+	}
+
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	channel = idr_find(&glink->rcids, cid);
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+	if (!channel) {
+		dev_err(glink->dev, "intents for non-existing channel\n");
+		qcom_glink_rx_advance(glink, ALIGN(msglen, 8));
+		return;
+	}
+
+	msg = kmalloc(msglen, GFP_ATOMIC);
+	if (!msg)
+		return;
+
+	qcom_glink_rx_peak(glink, msg, 0, msglen);
+
+	for (i = 0; i < count; ++i) {
+		intent = kzalloc(sizeof(*intent), GFP_ATOMIC);
+		if (!intent)
+			break;
+
+		intent->id = le32_to_cpu(msg->intents[i].iid);
+		intent->size = le32_to_cpu(msg->intents[i].size);
+
+		spin_lock_irqsave(&channel->intent_lock, flags);
+		ret = idr_alloc(&channel->riids, intent,
+				intent->id, intent->id + 1, GFP_ATOMIC);
+		spin_unlock_irqrestore(&channel->intent_lock, flags);
+
+		if (ret < 0)
+			dev_err(glink->dev, "failed to store remote intent\n");
+	}
+
+	kfree(msg);
+	qcom_glink_rx_advance(glink, ALIGN(msglen, 8));
+}
+
+static int qcom_glink_rx_open_ack(struct qcom_glink *glink, unsigned int lcid)
+{
+	struct glink_channel *channel;
+
+	spin_lock(&glink->idr_lock);
+	channel = idr_find(&glink->lcids, lcid);
+	spin_unlock(&glink->idr_lock);
+	if (!channel) {
+		dev_err(glink->dev, "Invalid open ack packet\n");
+		return -EINVAL;
+	}
+
+	complete_all(&channel->open_ack);
+
+	return 0;
+}
+
+static irqreturn_t qcom_glink_native_intr(int irq, void *data)
+{
+	struct qcom_glink *glink = data;
+	struct glink_msg msg;
+	unsigned int param1;
+	unsigned int param2;
+	unsigned int avail;
+	unsigned int cmd;
+	int ret = 0;
+
+	/* To wakeup any blocking writers */
+	wake_up_all(&glink->tx_avail_notify);
+
+	for (;;) {
+		avail = qcom_glink_rx_avail(glink);
+		if (avail < sizeof(msg))
+			break;
+
+		qcom_glink_rx_peak(glink, &msg, 0, sizeof(msg));
+
+		cmd = le16_to_cpu(msg.cmd);
+		param1 = le16_to_cpu(msg.param1);
+		param2 = le32_to_cpu(msg.param2);
+
+		switch (cmd) {
+		case RPM_CMD_VERSION:
+		case RPM_CMD_VERSION_ACK:
+		case RPM_CMD_CLOSE:
+		case RPM_CMD_CLOSE_ACK:
+		case RPM_CMD_RX_INTENT_REQ:
+			ret = qcom_glink_rx_defer(glink, 0);
+			break;
+		case RPM_CMD_OPEN_ACK:
+			ret = qcom_glink_rx_open_ack(glink, param1);
+			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
+			break;
+		case RPM_CMD_OPEN:
+			ret = qcom_glink_rx_defer(glink, param2);
+			break;
+		case RPM_CMD_TX_DATA:
+		case RPM_CMD_TX_DATA_CONT:
+			ret = qcom_glink_rx_data(glink, avail);
+			break;
+		case RPM_CMD_READ_NOTIF:
+			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
+
+			mbox_send_message(glink->mbox_chan, NULL);
+			mbox_client_txdone(glink->mbox_chan, 0);
+			break;
+		case RPM_CMD_INTENT:
+			qcom_glink_handle_intent(glink, param1, param2, avail);
+			break;
+		case RPM_CMD_RX_DONE:
+			qcom_glink_handle_rx_done(glink, param1, param2, false);
+			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
+			break;
+		case RPM_CMD_RX_DONE_W_REUSE:
+			qcom_glink_handle_rx_done(glink, param1, param2, true);
+			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
+			break;
+		case RPM_CMD_RX_INTENT_REQ_ACK:
+			qcom_glink_handle_intent_req_ack(glink, param1, param2);
+			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
+			break;
+		default:
+			dev_err(glink->dev, "unhandled rx cmd: %d\n", cmd);
+			ret = -EINVAL;
+			break;
+		}
+
+		if (ret)
+			break;
+	}
+
+	return IRQ_HANDLED;
+}
+
+/* Locally initiated rpmsg_create_ept */
+static struct glink_channel *qcom_glink_create_local(struct qcom_glink *glink,
+						     const char *name)
+{
+	struct glink_channel *channel;
+	int ret;
+	unsigned long flags;
+
+	channel = qcom_glink_alloc_channel(glink, name);
+	if (IS_ERR(channel))
+		return ERR_CAST(channel);
+
+	ret = qcom_glink_send_open_req(glink, channel);
+	if (ret)
+		goto release_channel;
+
+	ret = wait_for_completion_timeout(&channel->open_ack, 5 * HZ);
+	if (!ret)
+		goto err_timeout;
+
+	ret = wait_for_completion_timeout(&channel->open_req, 5 * HZ);
+	if (!ret)
+		goto err_timeout;
+
+	qcom_glink_send_open_ack(glink, channel);
+
+	return channel;
+
+err_timeout:
+	/* qcom_glink_send_open_req() did register the channel in lcids*/
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	idr_remove(&glink->lcids, channel->lcid);
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+
+release_channel:
+	/* Release qcom_glink_send_open_req() reference */
+	kref_put(&channel->refcount, qcom_glink_channel_release);
+	/* Release qcom_glink_alloc_channel() reference */
+	kref_put(&channel->refcount, qcom_glink_channel_release);
+
+	return ERR_PTR(-ETIMEDOUT);
+}
+
+/* Remote initiated rpmsg_create_ept */
+static int qcom_glink_create_remote(struct qcom_glink *glink,
+				    struct glink_channel *channel)
+{
+	int ret;
+
+	qcom_glink_send_open_ack(glink, channel);
+
+	ret = qcom_glink_send_open_req(glink, channel);
+	if (ret)
+		goto close_link;
+
+	ret = wait_for_completion_timeout(&channel->open_ack, 5 * HZ);
+	if (!ret) {
+		ret = -ETIMEDOUT;
+		goto close_link;
+	}
+
+	return 0;
+
+close_link:
+	/*
+	 * Send a close request to "undo" our open-ack. The close-ack will
+	 * release qcom_glink_send_open_req() reference and the last reference
+	 * will be relesed after receiving remote_close or transport unregister
+	 * by calling qcom_glink_native_remove().
+	 */
+	qcom_glink_send_close_req(glink, channel);
+
+	return ret;
+}
+
+static struct rpmsg_endpoint *qcom_glink_create_ept(struct rpmsg_device *rpdev,
+						    rpmsg_rx_cb_t cb,
+						    void *priv,
+						    struct rpmsg_channel_info
+									chinfo)
+{
+	struct glink_channel *parent = to_glink_channel(rpdev->ept);
+	struct glink_channel *channel;
+	struct qcom_glink *glink = parent->glink;
+	struct rpmsg_endpoint *ept;
+	const char *name = chinfo.name;
+	int cid;
+	int ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	idr_for_each_entry(&glink->rcids, channel, cid) {
+		if (!strcmp(channel->name, name))
+			break;
+	}
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+
+	if (!channel) {
+		channel = qcom_glink_create_local(glink, name);
+		if (IS_ERR(channel))
+			return NULL;
+	} else {
+		ret = qcom_glink_create_remote(glink, channel);
+		if (ret)
+			return NULL;
+	}
+
+	ept = &channel->ept;
+	ept->rpdev = rpdev;
+	ept->cb = cb;
+	ept->priv = priv;
+	ept->ops = &glink_endpoint_ops;
+
+	return ept;
+}
+
+static int qcom_glink_announce_create(struct rpmsg_device *rpdev)
+{
+	struct glink_channel *channel = to_glink_channel(rpdev->ept);
+	struct device_node *np = rpdev->dev.of_node;
+	struct qcom_glink *glink = channel->glink;
+	struct glink_core_rx_intent *intent;
+	const struct property *prop = NULL;
+	__be32 defaults[] = { cpu_to_be32(SZ_1K), cpu_to_be32(5) };
+	int num_intents;
+	int num_groups = 1;
+	__be32 *val = defaults;
+	int size;
+
+	if (glink->intentless || !completion_done(&channel->open_ack))
+		return 0;
+
+	prop = of_find_property(np, "qcom,intents", NULL);
+	if (prop) {
+		val = prop->value;
+		num_groups = prop->length / sizeof(u32) / 2;
+	}
+
+	/* Channel is now open, advertise base set of intents */
+	while (num_groups--) {
+		size = be32_to_cpup(val++);
+		num_intents = be32_to_cpup(val++);
+		while (num_intents--) {
+			intent = qcom_glink_alloc_intent(glink, channel, size,
+							 true);
+			if (!intent)
+				break;
+
+			qcom_glink_advertise_intent(glink, channel, intent);
+		}
+	}
+	return 0;
+}
+
+static void qcom_glink_destroy_ept(struct rpmsg_endpoint *ept)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+	struct qcom_glink *glink = channel->glink;
+	unsigned long flags;
+
+	spin_lock_irqsave(&channel->recv_lock, flags);
+	channel->ept.cb = NULL;
+	spin_unlock_irqrestore(&channel->recv_lock, flags);
+
+	/* Decouple the potential rpdev from the channel */
+	channel->rpdev = NULL;
+
+	qcom_glink_send_close_req(glink, channel);
+}
+
+static int qcom_glink_request_intent(struct qcom_glink *glink,
+				     struct glink_channel *channel,
+				     size_t size)
+{
+	struct {
+		u16 id;
+		u16 cid;
+		u32 size;
+	} __packed cmd;
+
+	int ret;
+
+	mutex_lock(&channel->intent_req_lock);
+
+	reinit_completion(&channel->intent_req_comp);
+
+	cmd.id = RPM_CMD_RX_INTENT_REQ;
+	cmd.cid = channel->lcid;
+	cmd.size = size;
+
+	ret = qcom_glink_tx(glink, &cmd, sizeof(cmd), NULL, 0, true);
+	if (ret)
+		goto unlock;
+
+	ret = wait_for_completion_timeout(&channel->intent_req_comp, 10 * HZ);
+	if (!ret) {
+		dev_err(glink->dev, "intent request timed out\n");
+		ret = -ETIMEDOUT;
+	} else {
+		ret = channel->intent_req_result ? 0 : -ECANCELED;
+	}
+
+unlock:
+	mutex_unlock(&channel->intent_req_lock);
+	return ret;
+}
+
+static int __qcom_glink_send(struct glink_channel *channel,
+			     void *data, int len, bool wait)
+{
+	struct qcom_glink *glink = channel->glink;
+	struct glink_core_rx_intent *intent = NULL;
+	struct glink_core_rx_intent *tmp;
+	int iid = 0;
+	struct {
+		struct glink_msg msg;
+		__le32 chunk_size;
+		__le32 left_size;
+	} __packed req;
+	int ret;
+	unsigned long flags;
+	int chunk_size = len;
+	int left_size = 0;
+
+	if (!glink->intentless) {
+		while (!intent) {
+			spin_lock_irqsave(&channel->intent_lock, flags);
+			idr_for_each_entry(&channel->riids, tmp, iid) {
+				if (tmp->size >= len && !tmp->in_use) {
+					if (!intent)
+						intent = tmp;
+					else if (intent->size > tmp->size)
+						intent = tmp;
+					if (intent->size == len)
+						break;
+				}
+			}
+			if (intent)
+				intent->in_use = true;
+			spin_unlock_irqrestore(&channel->intent_lock, flags);
+
+			/* We found an available intent */
+			if (intent)
+				break;
+
+			if (!wait)
+				return -EBUSY;
+
+			ret = qcom_glink_request_intent(glink, channel, len);
+			if (ret < 0)
+				return ret;
+		}
+
+		iid = intent->id;
+	}
+
+	if (wait && chunk_size > SZ_8K) {
+		chunk_size = SZ_8K;
+		left_size = len - chunk_size;
+	}
+	req.msg.cmd = cpu_to_le16(RPM_CMD_TX_DATA);
+	req.msg.param1 = cpu_to_le16(channel->lcid);
+	req.msg.param2 = cpu_to_le32(iid);
+	req.chunk_size = cpu_to_le32(chunk_size);
+	req.left_size = cpu_to_le32(left_size);
+
+	ret = qcom_glink_tx(glink, &req, sizeof(req), data, chunk_size, wait);
+
+	/* Mark intent available if we failed */
+	if (ret) {
+		if (intent)
+			intent->in_use = false;
+		return ret;
+	}
+
+	while (left_size > 0) {
+		data = (void *)((char *)data + chunk_size);
+		chunk_size = left_size;
+		if (chunk_size > SZ_8K)
+			chunk_size = SZ_8K;
+		left_size -= chunk_size;
+
+		req.msg.cmd = cpu_to_le16(RPM_CMD_TX_DATA_CONT);
+		req.msg.param1 = cpu_to_le16(channel->lcid);
+		req.msg.param2 = cpu_to_le32(iid);
+		req.chunk_size = cpu_to_le32(chunk_size);
+		req.left_size = cpu_to_le32(left_size);
+
+		ret = qcom_glink_tx(glink, &req, sizeof(req), data,
+				    chunk_size, wait);
+
+		/* Mark intent available if we failed */
+		if (ret) {
+			if (intent)
+				intent->in_use = false;
+			break;
+		}
+	}
+	return ret;
+}
+
+static int qcom_glink_send(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+
+	return __qcom_glink_send(channel, data, len, true);
+}
+
+static int qcom_glink_trysend(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+
+	return __qcom_glink_send(channel, data, len, false);
+}
+
+static int qcom_glink_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+
+	return __qcom_glink_send(channel, data, len, true);
+}
+
+static int qcom_glink_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+
+	return __qcom_glink_send(channel, data, len, false);
+}
+
+/*
+ * Finds the device_node for the glink child interested in this channel.
+ */
+static struct device_node *qcom_glink_match_channel(struct device_node *node,
+						    const char *channel)
+{
+	struct device_node *child;
+	const char *name;
+	const char *key;
+	int ret;
+
+	for_each_available_child_of_node(node, child) {
+		key = "qcom,glink-channels";
+		ret = of_property_read_string(child, key, &name);
+		if (ret)
+			continue;
+
+		if (strcmp(name, channel) == 0)
+			return child;
+	}
+
+	return NULL;
+}
+
+static const struct rpmsg_device_ops glink_device_ops = {
+	.create_ept = qcom_glink_create_ept,
+	.announce_create = qcom_glink_announce_create,
+};
+
+static const struct rpmsg_endpoint_ops glink_endpoint_ops = {
+	.destroy_ept = qcom_glink_destroy_ept,
+	.send = qcom_glink_send,
+	.sendto = qcom_glink_sendto,
+	.trysend = qcom_glink_trysend,
+	.trysendto = qcom_glink_trysendto,
+};
+
+static void qcom_glink_rpdev_release(struct device *dev)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+
+	kfree(rpdev->driver_override);
+	kfree(rpdev);
+}
+
+static int qcom_glink_rx_open(struct qcom_glink *glink, unsigned int rcid,
+			      char *name)
+{
+	struct glink_channel *channel;
+	struct rpmsg_device *rpdev;
+	bool create_device = false;
+	struct device_node *node;
+	int lcid;
+	int ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	idr_for_each_entry(&glink->lcids, channel, lcid) {
+		if (!strcmp(channel->name, name))
+			break;
+	}
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+
+	if (!channel) {
+		channel = qcom_glink_alloc_channel(glink, name);
+		if (IS_ERR(channel))
+			return PTR_ERR(channel);
+
+		/* The opening dance was initiated by the remote */
+		create_device = true;
+	}
+
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	ret = idr_alloc(&glink->rcids, channel, rcid, rcid + 1, GFP_ATOMIC);
+	if (ret < 0) {
+		dev_err(glink->dev, "Unable to insert channel into rcid list\n");
+		spin_unlock_irqrestore(&glink->idr_lock, flags);
+		goto free_channel;
+	}
+	channel->rcid = ret;
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+
+	complete_all(&channel->open_req);
+
+	if (create_device) {
+		rpdev = kzalloc(sizeof(*rpdev), GFP_KERNEL);
+		if (!rpdev) {
+			ret = -ENOMEM;
+			goto rcid_remove;
+		}
+
+		rpdev->ept = &channel->ept;
+		strscpy_pad(rpdev->id.name, name, RPMSG_NAME_SIZE);
+		rpdev->src = RPMSG_ADDR_ANY;
+		rpdev->dst = RPMSG_ADDR_ANY;
+		rpdev->ops = &glink_device_ops;
+
+		node = qcom_glink_match_channel(glink->dev->of_node, name);
+		rpdev->dev.of_node = node;
+		rpdev->dev.parent = glink->dev;
+		rpdev->dev.release = qcom_glink_rpdev_release;
+
+		ret = rpmsg_register_device(rpdev);
+		if (ret)
+			goto rcid_remove;
+
+		channel->rpdev = rpdev;
+	}
+
+	return 0;
+
+rcid_remove:
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	idr_remove(&glink->rcids, channel->rcid);
+	channel->rcid = 0;
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+free_channel:
+	/* Release the reference, iff we took it */
+	if (create_device)
+		kref_put(&channel->refcount, qcom_glink_channel_release);
+
+	return ret;
+}
+
+static void qcom_glink_rx_close(struct qcom_glink *glink, unsigned int rcid)
+{
+	struct rpmsg_channel_info chinfo;
+	struct glink_channel *channel;
+	unsigned long flags;
+
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	channel = idr_find(&glink->rcids, rcid);
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+	if (WARN(!channel, "close request on unknown channel\n"))
+		return;
+
+	/* cancel pending rx_done work */
+	cancel_work_sync(&channel->intent_work);
+
+	if (channel->rpdev) {
+		strscpy_pad(chinfo.name, channel->name, sizeof(chinfo.name));
+		chinfo.src = RPMSG_ADDR_ANY;
+		chinfo.dst = RPMSG_ADDR_ANY;
+
+		rpmsg_unregister_device(glink->dev, &chinfo);
+	}
+	channel->rpdev = NULL;
+
+	qcom_glink_send_close_ack(glink, channel->rcid);
+
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	idr_remove(&glink->rcids, channel->rcid);
+	channel->rcid = 0;
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+
+	kref_put(&channel->refcount, qcom_glink_channel_release);
+}
+
+static void qcom_glink_rx_close_ack(struct qcom_glink *glink, unsigned int lcid)
+{
+	struct rpmsg_channel_info chinfo;
+	struct glink_channel *channel;
+	unsigned long flags;
+
+	/* To wakeup any blocking writers */
+	wake_up_all(&glink->tx_avail_notify);
+
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	channel = idr_find(&glink->lcids, lcid);
+	if (WARN(!channel, "close ack on unknown channel\n")) {
+		spin_unlock_irqrestore(&glink->idr_lock, flags);
+		return;
+	}
+
+	idr_remove(&glink->lcids, channel->lcid);
+	channel->lcid = 0;
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+
+	/* Decouple the potential rpdev from the channel */
+	if (channel->rpdev) {
+		strscpy(chinfo.name, channel->name, sizeof(chinfo.name));
+		chinfo.src = RPMSG_ADDR_ANY;
+		chinfo.dst = RPMSG_ADDR_ANY;
+
+		rpmsg_unregister_device(glink->dev, &chinfo);
+	}
+	channel->rpdev = NULL;
+
+	kref_put(&channel->refcount, qcom_glink_channel_release);
+}
+
+static void qcom_glink_work(struct work_struct *work)
+{
+	struct qcom_glink *glink = container_of(work, struct qcom_glink,
+						rx_work);
+	struct glink_defer_cmd *dcmd;
+	struct glink_msg *msg;
+	unsigned long flags;
+	unsigned int param1;
+	unsigned int param2;
+	unsigned int cmd;
+
+	for (;;) {
+		spin_lock_irqsave(&glink->rx_lock, flags);
+		if (list_empty(&glink->rx_queue)) {
+			spin_unlock_irqrestore(&glink->rx_lock, flags);
+			break;
+		}
+		dcmd = list_first_entry(&glink->rx_queue,
+					struct glink_defer_cmd, node);
+		list_del(&dcmd->node);
+		spin_unlock_irqrestore(&glink->rx_lock, flags);
+
+		msg = &dcmd->msg;
+		cmd = le16_to_cpu(msg->cmd);
+		param1 = le16_to_cpu(msg->param1);
+		param2 = le32_to_cpu(msg->param2);
+
+		switch (cmd) {
+		case RPM_CMD_VERSION:
+			qcom_glink_receive_version(glink, param1, param2);
+			break;
+		case RPM_CMD_VERSION_ACK:
+			qcom_glink_receive_version_ack(glink, param1, param2);
+			break;
+		case RPM_CMD_OPEN:
+			qcom_glink_rx_open(glink, param1, msg->data);
+			break;
+		case RPM_CMD_CLOSE:
+			qcom_glink_rx_close(glink, param1);
+			break;
+		case RPM_CMD_CLOSE_ACK:
+			qcom_glink_rx_close_ack(glink, param1);
+			break;
+		case RPM_CMD_RX_INTENT_REQ:
+			qcom_glink_handle_intent_req(glink, param1, param2);
+			break;
+		default:
+			WARN(1, "Unknown defer object %d\n", cmd);
+			break;
+		}
+
+		kfree(dcmd);
+	}
+}
+
+static void qcom_glink_cancel_rx_work(struct qcom_glink *glink)
+{
+	struct glink_defer_cmd *dcmd;
+	struct glink_defer_cmd *tmp;
+
+	/* cancel any pending deferred rx_work */
+	cancel_work_sync(&glink->rx_work);
+
+	list_for_each_entry_safe(dcmd, tmp, &glink->rx_queue, node)
+		kfree(dcmd);
+}
+
+static ssize_t rpmsg_name_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	int ret = 0;
+	const char *name;
+
+	ret = of_property_read_string(dev->of_node, "label", &name);
+	if (ret < 0)
+		name = dev->of_node->name;
+
+	return sysfs_emit(buf, "%s\n", name);
+}
+static DEVICE_ATTR_RO(rpmsg_name);
+
+static struct attribute *qcom_glink_attrs[] = {
+	&dev_attr_rpmsg_name.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(qcom_glink);
+
+static void qcom_glink_device_release(struct device *dev)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+	struct glink_channel *channel = to_glink_channel(rpdev->ept);
+
+	/* Release qcom_glink_alloc_channel() reference */
+	kref_put(&channel->refcount, qcom_glink_channel_release);
+	kfree(rpdev->driver_override);
+	kfree(rpdev);
+}
+
+static int qcom_glink_create_chrdev(struct qcom_glink *glink)
+{
+	struct rpmsg_device *rpdev;
+	struct glink_channel *channel;
+
+	rpdev = kzalloc(sizeof(*rpdev), GFP_KERNEL);
+	if (!rpdev)
+		return -ENOMEM;
+
+	channel = qcom_glink_alloc_channel(glink, "rpmsg_chrdev");
+	if (IS_ERR(channel)) {
+		kfree(rpdev);
+		return PTR_ERR(channel);
+	}
+	channel->rpdev = rpdev;
+
+	rpdev->ept = &channel->ept;
+	rpdev->ops = &glink_device_ops;
+	rpdev->dev.parent = glink->dev;
+	rpdev->dev.release = qcom_glink_device_release;
+
+	return rpmsg_ctrldev_register_device(rpdev);
+}
+
+struct qcom_glink *qcom_glink_native_probe(struct device *dev,
+					   unsigned long features,
+					   struct qcom_glink_pipe *rx,
+					   struct qcom_glink_pipe *tx,
+					   bool intentless)
+{
+	int irq;
+	int ret;
+	struct qcom_glink *glink;
+
+	glink = devm_kzalloc(dev, sizeof(*glink), GFP_KERNEL);
+	if (!glink)
+		return ERR_PTR(-ENOMEM);
+
+	glink->dev = dev;
+	glink->tx_pipe = tx;
+	glink->rx_pipe = rx;
+
+	glink->features = features;
+	glink->intentless = intentless;
+
+	spin_lock_init(&glink->tx_lock);
+	spin_lock_init(&glink->rx_lock);
+	INIT_LIST_HEAD(&glink->rx_queue);
+	INIT_WORK(&glink->rx_work, qcom_glink_work);
+	init_waitqueue_head(&glink->tx_avail_notify);
+
+	spin_lock_init(&glink->idr_lock);
+	idr_init(&glink->lcids);
+	idr_init(&glink->rcids);
+
+	glink->dev->groups = qcom_glink_groups;
+
+	ret = device_add_groups(dev, qcom_glink_groups);
+	if (ret)
+		dev_err(dev, "failed to add groups\n");
+
+	glink->mbox_client.dev = dev;
+	glink->mbox_client.knows_txdone = true;
+	glink->mbox_chan = mbox_request_channel(&glink->mbox_client, 0);
+	if (IS_ERR(glink->mbox_chan)) {
+		if (PTR_ERR(glink->mbox_chan) != -EPROBE_DEFER)
+			dev_err(dev, "failed to acquire IPC channel\n");
+		return ERR_CAST(glink->mbox_chan);
+	}
+
+	irq = of_irq_get(dev->of_node, 0);
+	ret = devm_request_irq(dev, irq,
+			       qcom_glink_native_intr,
+			       IRQF_NO_SUSPEND | IRQF_SHARED,
+			       "glink-native", glink);
+	if (ret) {
+		dev_err(dev, "failed to request IRQ\n");
+		return ERR_PTR(ret);
+	}
+
+	glink->irq = irq;
+
+	ret = qcom_glink_send_version(glink);
+	if (ret)
+		return ERR_PTR(ret);
+
+	ret = qcom_glink_create_chrdev(glink);
+	if (ret)
+		dev_err(glink->dev, "failed to register chrdev\n");
+
+	return glink;
+}
+EXPORT_SYMBOL_GPL(qcom_glink_native_probe);
+
+static int qcom_glink_remove_device(struct device *dev, void *data)
+{
+	device_unregister(dev);
+
+	return 0;
+}
+
+void qcom_glink_native_remove(struct qcom_glink *glink)
+{
+	struct glink_channel *channel;
+	int cid;
+	int ret;
+
+	disable_irq(glink->irq);
+	qcom_glink_cancel_rx_work(glink);
+
+	ret = device_for_each_child(glink->dev, NULL, qcom_glink_remove_device);
+	if (ret)
+		dev_warn(glink->dev, "Can't remove GLINK devices: %d\n", ret);
+
+	/* Release any defunct local channels, waiting for close-ack */
+	idr_for_each_entry(&glink->lcids, channel, cid)
+		kref_put(&channel->refcount, qcom_glink_channel_release);
+
+	/* Release any defunct local channels, waiting for close-req */
+	idr_for_each_entry(&glink->rcids, channel, cid)
+		kref_put(&channel->refcount, qcom_glink_channel_release);
+
+	idr_destroy(&glink->lcids);
+	idr_destroy(&glink->rcids);
+	mbox_free_channel(glink->mbox_chan);
+}
+EXPORT_SYMBOL_GPL(qcom_glink_native_remove);
+
+void qcom_glink_native_unregister(struct qcom_glink *glink)
+{
+	device_unregister(glink->dev);
+}
+EXPORT_SYMBOL_GPL(qcom_glink_native_unregister);
+
+MODULE_DESCRIPTION("Qualcomm GLINK driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/rpmsg/qcom_glink_native.h b/drivers/rpmsg/qcom_glink_native.h
new file mode 100644
index 000000000..624184fc4
--- /dev/null
+++ b/drivers/rpmsg/qcom_glink_native.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2016-2017, Linaro Ltd
+ */
+
+#ifndef __QCOM_GLINK_NATIVE_H__
+#define __QCOM_GLINK_NATIVE_H__
+
+#define GLINK_FEATURE_INTENT_REUSE	BIT(0)
+#define GLINK_FEATURE_MIGRATION		BIT(1)
+#define GLINK_FEATURE_TRACER_PKT	BIT(2)
+
+struct qcom_glink_pipe {
+	size_t length;
+
+	size_t (*avail)(struct qcom_glink_pipe *glink_pipe);
+
+	void (*peak)(struct qcom_glink_pipe *glink_pipe, void *data,
+		     unsigned int offset, size_t count);
+	void (*advance)(struct qcom_glink_pipe *glink_pipe, size_t count);
+
+	void (*write)(struct qcom_glink_pipe *glink_pipe,
+		      const void *hdr, size_t hlen,
+		      const void *data, size_t dlen);
+};
+
+struct qcom_glink;
+
+struct qcom_glink *qcom_glink_native_probe(struct device *dev,
+					   unsigned long features,
+					   struct qcom_glink_pipe *rx,
+					   struct qcom_glink_pipe *tx,
+					   bool intentless);
+void qcom_glink_native_remove(struct qcom_glink *glink);
+
+void qcom_glink_native_unregister(struct qcom_glink *glink);
+#endif
diff --git a/drivers/rpmsg/qcom_glink_rpm.c b/drivers/rpmsg/qcom_glink_rpm.c
new file mode 100644
index 000000000..f64f45d1a
--- /dev/null
+++ b/drivers/rpmsg/qcom_glink_rpm.c
@@ -0,0 +1,351 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2016-2017, Linaro Ltd
+ */
+
+#include <linux/idr.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/list.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/rpmsg.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+#include <linux/mailbox_client.h>
+
+#include "rpmsg_internal.h"
+#include "qcom_glink_native.h"
+
+#define RPM_TOC_SIZE		256
+#define RPM_TOC_MAGIC		0x67727430 /* grt0 */
+#define RPM_TOC_MAX_ENTRIES	((RPM_TOC_SIZE - sizeof(struct rpm_toc)) / \
+				 sizeof(struct rpm_toc_entry))
+
+#define RPM_TX_FIFO_ID		0x61703272 /* ap2r */
+#define RPM_RX_FIFO_ID		0x72326170 /* r2ap */
+
+#define to_rpm_pipe(p) container_of(p, struct glink_rpm_pipe, native)
+
+struct rpm_toc_entry {
+	__le32 id;
+	__le32 offset;
+	__le32 size;
+} __packed;
+
+struct rpm_toc {
+	__le32 magic;
+	__le32 count;
+
+	struct rpm_toc_entry entries[];
+} __packed;
+
+struct glink_rpm_pipe {
+	struct qcom_glink_pipe native;
+
+	void __iomem *tail;
+	void __iomem *head;
+
+	void __iomem *fifo;
+};
+
+static size_t glink_rpm_rx_avail(struct qcom_glink_pipe *glink_pipe)
+{
+	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
+	unsigned int head;
+	unsigned int tail;
+
+	head = readl(pipe->head);
+	tail = readl(pipe->tail);
+
+	if (head < tail)
+		return pipe->native.length - tail + head;
+	else
+		return head - tail;
+}
+
+static void glink_rpm_rx_peak(struct qcom_glink_pipe *glink_pipe,
+			      void *data, unsigned int offset, size_t count)
+{
+	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
+	unsigned int tail;
+	size_t len;
+
+	tail = readl(pipe->tail);
+	tail += offset;
+	if (tail >= pipe->native.length)
+		tail -= pipe->native.length;
+
+	len = min_t(size_t, count, pipe->native.length - tail);
+	if (len) {
+		__ioread32_copy(data, pipe->fifo + tail,
+				len / sizeof(u32));
+	}
+
+	if (len != count) {
+		__ioread32_copy(data + len, pipe->fifo,
+				(count - len) / sizeof(u32));
+	}
+}
+
+static void glink_rpm_rx_advance(struct qcom_glink_pipe *glink_pipe,
+				 size_t count)
+{
+	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
+	unsigned int tail;
+
+	tail = readl(pipe->tail);
+
+	tail += count;
+	if (tail >= pipe->native.length)
+		tail -= pipe->native.length;
+
+	writel(tail, pipe->tail);
+}
+
+static size_t glink_rpm_tx_avail(struct qcom_glink_pipe *glink_pipe)
+{
+	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
+	unsigned int head;
+	unsigned int tail;
+
+	head = readl(pipe->head);
+	tail = readl(pipe->tail);
+
+	if (tail <= head)
+		return pipe->native.length - head + tail;
+	else
+		return tail - head;
+}
+
+static unsigned int glink_rpm_tx_write_one(struct glink_rpm_pipe *pipe,
+					   unsigned int head,
+					   const void *data, size_t count)
+{
+	size_t len;
+
+	len = min_t(size_t, count, pipe->native.length - head);
+	if (len) {
+		__iowrite32_copy(pipe->fifo + head, data,
+				 len / sizeof(u32));
+	}
+
+	if (len != count) {
+		__iowrite32_copy(pipe->fifo, data + len,
+				 (count - len) / sizeof(u32));
+	}
+
+	head += count;
+	if (head >= pipe->native.length)
+		head -= pipe->native.length;
+
+	return head;
+}
+
+static void glink_rpm_tx_write(struct qcom_glink_pipe *glink_pipe,
+			       const void *hdr, size_t hlen,
+			       const void *data, size_t dlen)
+{
+	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
+	size_t tlen = hlen + dlen;
+	size_t aligned_dlen;
+	unsigned int head;
+	char padding[8] = {0};
+	size_t pad;
+
+	/* Header length comes from glink native and is always 4 byte aligned */
+	if (WARN(hlen % 4, "Glink Header length must be 4 bytes aligned\n"))
+		return;
+
+	/*
+	 * Move the unaligned tail of the message to the padding chunk, to
+	 * ensure word aligned accesses
+	 */
+	aligned_dlen = ALIGN_DOWN(dlen, 4);
+	if (aligned_dlen != dlen)
+		memcpy(padding, data + aligned_dlen, dlen - aligned_dlen);
+
+	head = readl(pipe->head);
+	head = glink_rpm_tx_write_one(pipe, head, hdr, hlen);
+	head = glink_rpm_tx_write_one(pipe, head, data, aligned_dlen);
+
+	pad = ALIGN(tlen, 8) - ALIGN_DOWN(tlen, 4);
+	if (pad)
+		head = glink_rpm_tx_write_one(pipe, head, padding, pad);
+	writel(head, pipe->head);
+}
+
+static int glink_rpm_parse_toc(struct device *dev,
+			       void __iomem *msg_ram,
+			       size_t msg_ram_size,
+			       struct glink_rpm_pipe *rx,
+			       struct glink_rpm_pipe *tx)
+{
+	struct rpm_toc *toc;
+	int num_entries;
+	unsigned int id;
+	size_t offset;
+	size_t size;
+	void *buf;
+	int i;
+
+	buf = kzalloc(RPM_TOC_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	__ioread32_copy(buf, msg_ram + msg_ram_size - RPM_TOC_SIZE,
+			RPM_TOC_SIZE / sizeof(u32));
+
+	toc = buf;
+
+	if (le32_to_cpu(toc->magic) != RPM_TOC_MAGIC) {
+		dev_err(dev, "RPM TOC has invalid magic\n");
+		goto err_inval;
+	}
+
+	num_entries = le32_to_cpu(toc->count);
+	if (num_entries > RPM_TOC_MAX_ENTRIES) {
+		dev_err(dev, "Invalid number of toc entries\n");
+		goto err_inval;
+	}
+
+	for (i = 0; i < num_entries; i++) {
+		id = le32_to_cpu(toc->entries[i].id);
+		offset = le32_to_cpu(toc->entries[i].offset);
+		size = le32_to_cpu(toc->entries[i].size);
+
+		if (offset > msg_ram_size || offset + size > msg_ram_size) {
+			dev_err(dev, "TOC entry with invalid size\n");
+			continue;
+		}
+
+		switch (id) {
+		case RPM_RX_FIFO_ID:
+			rx->native.length = size;
+
+			rx->tail = msg_ram + offset;
+			rx->head = msg_ram + offset + sizeof(u32);
+			rx->fifo = msg_ram + offset + 2 * sizeof(u32);
+			break;
+		case RPM_TX_FIFO_ID:
+			tx->native.length = size;
+
+			tx->tail = msg_ram + offset;
+			tx->head = msg_ram + offset + sizeof(u32);
+			tx->fifo = msg_ram + offset + 2 * sizeof(u32);
+			break;
+		}
+	}
+
+	if (!rx->fifo || !tx->fifo) {
+		dev_err(dev, "Unable to find rx and tx descriptors\n");
+		goto err_inval;
+	}
+
+	kfree(buf);
+	return 0;
+
+err_inval:
+	kfree(buf);
+	return -EINVAL;
+}
+
+static int glink_rpm_probe(struct platform_device *pdev)
+{
+	struct qcom_glink *glink;
+	struct glink_rpm_pipe *rx_pipe;
+	struct glink_rpm_pipe *tx_pipe;
+	struct device_node *np;
+	void __iomem *msg_ram;
+	size_t msg_ram_size;
+	struct device *dev = &pdev->dev;
+	struct resource r;
+	int ret;
+
+	rx_pipe = devm_kzalloc(&pdev->dev, sizeof(*rx_pipe), GFP_KERNEL);
+	tx_pipe = devm_kzalloc(&pdev->dev, sizeof(*tx_pipe), GFP_KERNEL);
+	if (!rx_pipe || !tx_pipe)
+		return -ENOMEM;
+
+	np = of_parse_phandle(dev->of_node, "qcom,rpm-msg-ram", 0);
+	ret = of_address_to_resource(np, 0, &r);
+	of_node_put(np);
+	if (ret)
+		return ret;
+
+	msg_ram = devm_ioremap(dev, r.start, resource_size(&r));
+	msg_ram_size = resource_size(&r);
+	if (!msg_ram)
+		return -ENOMEM;
+
+	ret = glink_rpm_parse_toc(dev, msg_ram, msg_ram_size,
+				  rx_pipe, tx_pipe);
+	if (ret)
+		return ret;
+
+	/* Pipe specific accessors */
+	rx_pipe->native.avail = glink_rpm_rx_avail;
+	rx_pipe->native.peak = glink_rpm_rx_peak;
+	rx_pipe->native.advance = glink_rpm_rx_advance;
+	tx_pipe->native.avail = glink_rpm_tx_avail;
+	tx_pipe->native.write = glink_rpm_tx_write;
+
+	writel(0, tx_pipe->head);
+	writel(0, rx_pipe->tail);
+
+	glink = qcom_glink_native_probe(&pdev->dev,
+					0,
+					&rx_pipe->native,
+					&tx_pipe->native,
+					true);
+	if (IS_ERR(glink))
+		return PTR_ERR(glink);
+
+	platform_set_drvdata(pdev, glink);
+
+	return 0;
+}
+
+static int glink_rpm_remove(struct platform_device *pdev)
+{
+	struct qcom_glink *glink = platform_get_drvdata(pdev);
+
+	qcom_glink_native_remove(glink);
+
+	return 0;
+}
+
+static const struct of_device_id glink_rpm_of_match[] = {
+	{ .compatible = "qcom,glink-rpm" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, glink_rpm_of_match);
+
+static struct platform_driver glink_rpm_driver = {
+	.probe = glink_rpm_probe,
+	.remove = glink_rpm_remove,
+	.driver = {
+		.name = "qcom_glink_rpm",
+		.of_match_table = glink_rpm_of_match,
+	},
+};
+
+static int __init glink_rpm_init(void)
+{
+	return platform_driver_register(&glink_rpm_driver);
+}
+subsys_initcall(glink_rpm_init);
+
+static void __exit glink_rpm_exit(void)
+{
+	platform_driver_unregister(&glink_rpm_driver);
+}
+module_exit(glink_rpm_exit);
+
+MODULE_AUTHOR("Bjorn Andersson <bjorn.andersson@linaro.org>");
+MODULE_DESCRIPTION("Qualcomm GLINK RPM driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/rpmsg/qcom_glink_smem.c b/drivers/rpmsg/qcom_glink_smem.c
new file mode 100644
index 000000000..579bc4443
--- /dev/null
+++ b/drivers/rpmsg/qcom_glink_smem.c
@@ -0,0 +1,306 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2016, Linaro Ltd
+ */
+
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/syscon.h>
+#include <linux/slab.h>
+#include <linux/rpmsg.h>
+#include <linux/idr.h>
+#include <linux/circ_buf.h>
+#include <linux/soc/qcom/smem.h>
+#include <linux/sizes.h>
+#include <linux/delay.h>
+#include <linux/regmap.h>
+#include <linux/workqueue.h>
+#include <linux/list.h>
+
+#include <linux/rpmsg/qcom_glink.h>
+
+#include "qcom_glink_native.h"
+
+#define FIFO_FULL_RESERVE 8
+#define FIFO_ALIGNMENT 8
+#define TX_BLOCKED_CMD_RESERVE 8 /* size of struct read_notif_request */
+
+#define SMEM_GLINK_NATIVE_XPRT_DESCRIPTOR	478
+#define SMEM_GLINK_NATIVE_XPRT_FIFO_0		479
+#define SMEM_GLINK_NATIVE_XPRT_FIFO_1		480
+
+struct glink_smem_pipe {
+	struct qcom_glink_pipe native;
+
+	__le32 *tail;
+	__le32 *head;
+
+	void *fifo;
+
+	int remote_pid;
+};
+
+#define to_smem_pipe(p) container_of(p, struct glink_smem_pipe, native)
+
+static size_t glink_smem_rx_avail(struct qcom_glink_pipe *np)
+{
+	struct glink_smem_pipe *pipe = to_smem_pipe(np);
+	size_t len;
+	void *fifo;
+	u32 head;
+	u32 tail;
+
+	if (!pipe->fifo) {
+		fifo = qcom_smem_get(pipe->remote_pid,
+				     SMEM_GLINK_NATIVE_XPRT_FIFO_1, &len);
+		if (IS_ERR(fifo)) {
+			pr_err("failed to acquire RX fifo handle: %ld\n",
+			       PTR_ERR(fifo));
+			return 0;
+		}
+
+		pipe->fifo = fifo;
+		pipe->native.length = len;
+	}
+
+	head = le32_to_cpu(*pipe->head);
+	tail = le32_to_cpu(*pipe->tail);
+
+	if (head < tail)
+		return pipe->native.length - tail + head;
+	else
+		return head - tail;
+}
+
+static void glink_smem_rx_peak(struct qcom_glink_pipe *np,
+			       void *data, unsigned int offset, size_t count)
+{
+	struct glink_smem_pipe *pipe = to_smem_pipe(np);
+	size_t len;
+	u32 tail;
+
+	tail = le32_to_cpu(*pipe->tail);
+	tail += offset;
+	if (tail >= pipe->native.length)
+		tail -= pipe->native.length;
+
+	len = min_t(size_t, count, pipe->native.length - tail);
+	if (len)
+		memcpy_fromio(data, pipe->fifo + tail, len);
+
+	if (len != count)
+		memcpy_fromio(data + len, pipe->fifo, (count - len));
+}
+
+static void glink_smem_rx_advance(struct qcom_glink_pipe *np,
+				  size_t count)
+{
+	struct glink_smem_pipe *pipe = to_smem_pipe(np);
+	u32 tail;
+
+	tail = le32_to_cpu(*pipe->tail);
+
+	tail += count;
+	if (tail >= pipe->native.length)
+		tail -= pipe->native.length;
+
+	*pipe->tail = cpu_to_le32(tail);
+}
+
+static size_t glink_smem_tx_avail(struct qcom_glink_pipe *np)
+{
+	struct glink_smem_pipe *pipe = to_smem_pipe(np);
+	u32 head;
+	u32 tail;
+	u32 avail;
+
+	head = le32_to_cpu(*pipe->head);
+	tail = le32_to_cpu(*pipe->tail);
+
+	if (tail <= head)
+		avail = pipe->native.length - head + tail;
+	else
+		avail = tail - head;
+
+	if (avail < (FIFO_FULL_RESERVE + TX_BLOCKED_CMD_RESERVE))
+		avail = 0;
+	else
+		avail -= FIFO_FULL_RESERVE + TX_BLOCKED_CMD_RESERVE;
+
+	return avail;
+}
+
+static unsigned int glink_smem_tx_write_one(struct glink_smem_pipe *pipe,
+					    unsigned int head,
+					    const void *data, size_t count)
+{
+	size_t len;
+
+	len = min_t(size_t, count, pipe->native.length - head);
+	if (len)
+		memcpy(pipe->fifo + head, data, len);
+
+	if (len != count)
+		memcpy(pipe->fifo, data + len, count - len);
+
+	head += count;
+	if (head >= pipe->native.length)
+		head -= pipe->native.length;
+
+	return head;
+}
+
+static void glink_smem_tx_write(struct qcom_glink_pipe *glink_pipe,
+				const void *hdr, size_t hlen,
+				const void *data, size_t dlen)
+{
+	struct glink_smem_pipe *pipe = to_smem_pipe(glink_pipe);
+	unsigned int head;
+
+	head = le32_to_cpu(*pipe->head);
+
+	head = glink_smem_tx_write_one(pipe, head, hdr, hlen);
+	head = glink_smem_tx_write_one(pipe, head, data, dlen);
+
+	/* Ensure head is always aligned to 8 bytes */
+	head = ALIGN(head, 8);
+	if (head >= pipe->native.length)
+		head -= pipe->native.length;
+
+	/* Ensure ordering of fifo and head update */
+	wmb();
+
+	*pipe->head = cpu_to_le32(head);
+}
+
+static void qcom_glink_smem_release(struct device *dev)
+{
+	kfree(dev);
+}
+
+struct qcom_glink *qcom_glink_smem_register(struct device *parent,
+					    struct device_node *node)
+{
+	struct glink_smem_pipe *rx_pipe;
+	struct glink_smem_pipe *tx_pipe;
+	struct qcom_glink *glink;
+	struct device *dev;
+	u32 remote_pid;
+	__le32 *descs;
+	size_t size;
+	int ret;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return ERR_PTR(-ENOMEM);
+
+	dev->parent = parent;
+	dev->of_node = node;
+	dev->release = qcom_glink_smem_release;
+	dev_set_name(dev, "%s:%pOFn", dev_name(parent->parent), node);
+	ret = device_register(dev);
+	if (ret) {
+		pr_err("failed to register glink edge\n");
+		put_device(dev);
+		return ERR_PTR(ret);
+	}
+
+	ret = of_property_read_u32(dev->of_node, "qcom,remote-pid",
+				   &remote_pid);
+	if (ret) {
+		dev_err(dev, "failed to parse qcom,remote-pid\n");
+		goto err_put_dev;
+	}
+
+	rx_pipe = devm_kzalloc(dev, sizeof(*rx_pipe), GFP_KERNEL);
+	tx_pipe = devm_kzalloc(dev, sizeof(*tx_pipe), GFP_KERNEL);
+	if (!rx_pipe || !tx_pipe) {
+		ret = -ENOMEM;
+		goto err_put_dev;
+	}
+
+	ret = qcom_smem_alloc(remote_pid,
+			      SMEM_GLINK_NATIVE_XPRT_DESCRIPTOR, 32);
+	if (ret && ret != -EEXIST) {
+		dev_err(dev, "failed to allocate glink descriptors\n");
+		goto err_put_dev;
+	}
+
+	descs = qcom_smem_get(remote_pid,
+			      SMEM_GLINK_NATIVE_XPRT_DESCRIPTOR, &size);
+	if (IS_ERR(descs)) {
+		dev_err(dev, "failed to acquire xprt descriptor\n");
+		ret = PTR_ERR(descs);
+		goto err_put_dev;
+	}
+
+	if (size != 32) {
+		dev_err(dev, "glink descriptor of invalid size\n");
+		ret = -EINVAL;
+		goto err_put_dev;
+	}
+
+	tx_pipe->tail = &descs[0];
+	tx_pipe->head = &descs[1];
+	rx_pipe->tail = &descs[2];
+	rx_pipe->head = &descs[3];
+
+	ret = qcom_smem_alloc(remote_pid, SMEM_GLINK_NATIVE_XPRT_FIFO_0,
+			      SZ_16K);
+	if (ret && ret != -EEXIST) {
+		dev_err(dev, "failed to allocate TX fifo\n");
+		goto err_put_dev;
+	}
+
+	tx_pipe->fifo = qcom_smem_get(remote_pid, SMEM_GLINK_NATIVE_XPRT_FIFO_0,
+				      &tx_pipe->native.length);
+	if (IS_ERR(tx_pipe->fifo)) {
+		dev_err(dev, "failed to acquire TX fifo\n");
+		ret = PTR_ERR(tx_pipe->fifo);
+		goto err_put_dev;
+	}
+
+	rx_pipe->native.avail = glink_smem_rx_avail;
+	rx_pipe->native.peak = glink_smem_rx_peak;
+	rx_pipe->native.advance = glink_smem_rx_advance;
+	rx_pipe->remote_pid = remote_pid;
+
+	tx_pipe->native.avail = glink_smem_tx_avail;
+	tx_pipe->native.write = glink_smem_tx_write;
+	tx_pipe->remote_pid = remote_pid;
+
+	*rx_pipe->tail = 0;
+	*tx_pipe->head = 0;
+
+	glink = qcom_glink_native_probe(dev,
+					GLINK_FEATURE_INTENT_REUSE,
+					&rx_pipe->native, &tx_pipe->native,
+					false);
+	if (IS_ERR(glink)) {
+		ret = PTR_ERR(glink);
+		goto err_put_dev;
+	}
+
+	return glink;
+
+err_put_dev:
+	device_unregister(dev);
+
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(qcom_glink_smem_register);
+
+void qcom_glink_smem_unregister(struct qcom_glink *glink)
+{
+	qcom_glink_native_remove(glink);
+	qcom_glink_native_unregister(glink);
+}
+EXPORT_SYMBOL_GPL(qcom_glink_smem_unregister);
+
+MODULE_AUTHOR("Bjorn Andersson <bjorn.andersson@linaro.org>");
+MODULE_DESCRIPTION("Qualcomm GLINK SMEM driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/rpmsg/qcom_glink_ssr.c b/drivers/rpmsg/qcom_glink_ssr.c
new file mode 100644
index 000000000..776d64446
--- /dev/null
+++ b/drivers/rpmsg/qcom_glink_ssr.c
@@ -0,0 +1,167 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2014-2017, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2017, Linaro Ltd.
+ */
+
+#include <linux/completion.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/rpmsg.h>
+#include <linux/rpmsg/qcom_glink.h>
+#include <linux/remoteproc/qcom_rproc.h>
+
+/**
+ * struct do_cleanup_msg - The data structure for an SSR do_cleanup message
+ * @version:	The G-Link SSR protocol version
+ * @command:	The G-Link SSR command - do_cleanup
+ * @seq_num:	Sequence number
+ * @name_len:	Length of the name of the subsystem being restarted
+ * @name:	G-Link edge name of the subsystem being restarted
+ */
+struct do_cleanup_msg {
+	__le32 version;
+	__le32 command;
+	__le32 seq_num;
+	__le32 name_len;
+	char name[32];
+};
+
+/**
+ * struct cleanup_done_msg - The data structure for an SSR cleanup_done message
+ * @version:	The G-Link SSR protocol version
+ * @response:	The G-Link SSR response to a do_cleanup command, cleanup_done
+ * @seq_num:	Sequence number
+ */
+struct cleanup_done_msg {
+	__le32 version;
+	__le32 response;
+	__le32 seq_num;
+};
+
+/*
+ * G-Link SSR protocol commands
+ */
+#define GLINK_SSR_DO_CLEANUP	0
+#define GLINK_SSR_CLEANUP_DONE	1
+
+struct glink_ssr {
+	struct device *dev;
+	struct rpmsg_endpoint *ept;
+
+	struct notifier_block nb;
+
+	u32 seq_num;
+	struct completion completion;
+};
+
+/* Notifier list for all registered glink_ssr instances */
+static BLOCKING_NOTIFIER_HEAD(ssr_notifiers);
+
+/**
+ * qcom_glink_ssr_notify() - notify GLINK SSR about stopped remoteproc
+ * @ssr_name:	name of the remoteproc that has been stopped
+ */
+void qcom_glink_ssr_notify(const char *ssr_name)
+{
+	blocking_notifier_call_chain(&ssr_notifiers, 0, (void *)ssr_name);
+}
+EXPORT_SYMBOL_GPL(qcom_glink_ssr_notify);
+
+static int qcom_glink_ssr_callback(struct rpmsg_device *rpdev,
+				   void *data, int len, void *priv, u32 addr)
+{
+	struct cleanup_done_msg *msg = data;
+	struct glink_ssr *ssr = dev_get_drvdata(&rpdev->dev);
+
+	if (len < sizeof(*msg)) {
+		dev_err(ssr->dev, "message too short\n");
+		return -EINVAL;
+	}
+
+	if (le32_to_cpu(msg->version) != 0)
+		return -EINVAL;
+
+	if (le32_to_cpu(msg->response) != GLINK_SSR_CLEANUP_DONE)
+		return 0;
+
+	if (le32_to_cpu(msg->seq_num) != ssr->seq_num) {
+		dev_err(ssr->dev, "invalid sequence number of response\n");
+		return -EINVAL;
+	}
+
+	complete(&ssr->completion);
+
+	return 0;
+}
+
+static int qcom_glink_ssr_notifier_call(struct notifier_block *nb,
+					unsigned long event,
+					void *data)
+{
+	struct glink_ssr *ssr = container_of(nb, struct glink_ssr, nb);
+	struct do_cleanup_msg msg;
+	char *ssr_name = data;
+	int ret;
+
+	ssr->seq_num++;
+	reinit_completion(&ssr->completion);
+
+	memset(&msg, 0, sizeof(msg));
+	msg.command = cpu_to_le32(GLINK_SSR_DO_CLEANUP);
+	msg.seq_num = cpu_to_le32(ssr->seq_num);
+	msg.name_len = cpu_to_le32(strlen(ssr_name));
+	strlcpy(msg.name, ssr_name, sizeof(msg.name));
+
+	ret = rpmsg_send(ssr->ept, &msg, sizeof(msg));
+	if (ret < 0)
+		dev_err(ssr->dev, "failed to send cleanup message\n");
+
+	ret = wait_for_completion_timeout(&ssr->completion, HZ);
+	if (!ret)
+		dev_err(ssr->dev, "timeout waiting for cleanup done message\n");
+
+	return NOTIFY_DONE;
+}
+
+static int qcom_glink_ssr_probe(struct rpmsg_device *rpdev)
+{
+	struct glink_ssr *ssr;
+
+	ssr = devm_kzalloc(&rpdev->dev, sizeof(*ssr), GFP_KERNEL);
+	if (!ssr)
+		return -ENOMEM;
+
+	init_completion(&ssr->completion);
+
+	ssr->dev = &rpdev->dev;
+	ssr->ept = rpdev->ept;
+	ssr->nb.notifier_call = qcom_glink_ssr_notifier_call;
+
+	dev_set_drvdata(&rpdev->dev, ssr);
+
+	return blocking_notifier_chain_register(&ssr_notifiers, &ssr->nb);
+}
+
+static void qcom_glink_ssr_remove(struct rpmsg_device *rpdev)
+{
+	struct glink_ssr *ssr = dev_get_drvdata(&rpdev->dev);
+
+	blocking_notifier_chain_unregister(&ssr_notifiers, &ssr->nb);
+}
+
+static const struct rpmsg_device_id qcom_glink_ssr_match[] = {
+	{ "glink_ssr" },
+	{}
+};
+
+static struct rpmsg_driver qcom_glink_ssr_driver = {
+	.probe = qcom_glink_ssr_probe,
+	.remove = qcom_glink_ssr_remove,
+	.callback = qcom_glink_ssr_callback,
+	.id_table = qcom_glink_ssr_match,
+	.drv = {
+		.name = "qcom_glink_ssr",
+	},
+};
+module_rpmsg_driver(qcom_glink_ssr_driver);
diff --git a/drivers/rpmsg/qcom_smd.c b/drivers/rpmsg/qcom_smd.c
new file mode 100644
index 000000000..1044cf03c
--- /dev/null
+++ b/drivers/rpmsg/qcom_smd.c
@@ -0,0 +1,1622 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2015, Sony Mobile Communications AB.
+ * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/mailbox_client.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/sched.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/soc/qcom/smem.h>
+#include <linux/wait.h>
+#include <linux/rpmsg.h>
+#include <linux/rpmsg/qcom_smd.h>
+
+#include "rpmsg_internal.h"
+
+/*
+ * The Qualcomm Shared Memory communication solution provides point-to-point
+ * channels for clients to send and receive streaming or packet based data.
+ *
+ * Each channel consists of a control item (channel info) and a ring buffer
+ * pair. The channel info carry information related to channel state, flow
+ * control and the offsets within the ring buffer.
+ *
+ * All allocated channels are listed in an allocation table, identifying the
+ * pair of items by name, type and remote processor.
+ *
+ * Upon creating a new channel the remote processor allocates channel info and
+ * ring buffer items from the smem heap and populate the allocation table. An
+ * interrupt is sent to the other end of the channel and a scan for new
+ * channels should be done. A channel never goes away, it will only change
+ * state.
+ *
+ * The remote processor signals it intent for bring up the communication
+ * channel by setting the state of its end of the channel to "opening" and
+ * sends out an interrupt. We detect this change and register a smd device to
+ * consume the channel. Upon finding a consumer we finish the handshake and the
+ * channel is up.
+ *
+ * Upon closing a channel, the remote processor will update the state of its
+ * end of the channel and signal us, we will then unregister any attached
+ * device and close our end of the channel.
+ *
+ * Devices attached to a channel can use the qcom_smd_send function to push
+ * data to the channel, this is done by copying the data into the tx ring
+ * buffer, updating the pointers in the channel info and signaling the remote
+ * processor.
+ *
+ * The remote processor does the equivalent when it transfer data and upon
+ * receiving the interrupt we check the channel info for new data and delivers
+ * this to the attached device. If the device is not ready to receive the data
+ * we leave it in the ring buffer for now.
+ */
+
+struct smd_channel_info;
+struct smd_channel_info_pair;
+struct smd_channel_info_word;
+struct smd_channel_info_word_pair;
+
+static const struct rpmsg_endpoint_ops qcom_smd_endpoint_ops;
+
+#define SMD_ALLOC_TBL_COUNT	2
+#define SMD_ALLOC_TBL_SIZE	64
+
+/*
+ * This lists the various smem heap items relevant for the allocation table and
+ * smd channel entries.
+ */
+static const struct {
+	unsigned alloc_tbl_id;
+	unsigned info_base_id;
+	unsigned fifo_base_id;
+} smem_items[SMD_ALLOC_TBL_COUNT] = {
+	{
+		.alloc_tbl_id = 13,
+		.info_base_id = 14,
+		.fifo_base_id = 338
+	},
+	{
+		.alloc_tbl_id = 266,
+		.info_base_id = 138,
+		.fifo_base_id = 202,
+	},
+};
+
+/**
+ * struct qcom_smd_edge - representing a remote processor
+ * @dev:		device associated with this edge
+ * @name:		name of this edge
+ * @of_node:		of_node handle for information related to this edge
+ * @edge_id:		identifier of this edge
+ * @remote_pid:		identifier of remote processor
+ * @irq:		interrupt for signals on this edge
+ * @ipc_regmap:		regmap handle holding the outgoing ipc register
+ * @ipc_offset:		offset within @ipc_regmap of the register for ipc
+ * @ipc_bit:		bit in the register at @ipc_offset of @ipc_regmap
+ * @mbox_client:	mailbox client handle
+ * @mbox_chan:		apcs ipc mailbox channel handle
+ * @channels:		list of all channels detected on this edge
+ * @channels_lock:	guard for modifications of @channels
+ * @allocated:		array of bitmaps representing already allocated channels
+ * @smem_available:	last available amount of smem triggering a channel scan
+ * @new_channel_event:	wait queue for new channel events
+ * @scan_work:		work item for discovering new channels
+ * @state_work:		work item for edge state changes
+ */
+struct qcom_smd_edge {
+	struct device dev;
+
+	const char *name;
+
+	struct device_node *of_node;
+	unsigned edge_id;
+	unsigned remote_pid;
+
+	int irq;
+
+	struct regmap *ipc_regmap;
+	int ipc_offset;
+	int ipc_bit;
+
+	struct mbox_client mbox_client;
+	struct mbox_chan *mbox_chan;
+
+	struct list_head channels;
+	spinlock_t channels_lock;
+
+	DECLARE_BITMAP(allocated[SMD_ALLOC_TBL_COUNT], SMD_ALLOC_TBL_SIZE);
+
+	unsigned smem_available;
+
+	wait_queue_head_t new_channel_event;
+
+	struct work_struct scan_work;
+	struct work_struct state_work;
+};
+
+/*
+ * SMD channel states.
+ */
+enum smd_channel_state {
+	SMD_CHANNEL_CLOSED,
+	SMD_CHANNEL_OPENING,
+	SMD_CHANNEL_OPENED,
+	SMD_CHANNEL_FLUSHING,
+	SMD_CHANNEL_CLOSING,
+	SMD_CHANNEL_RESET,
+	SMD_CHANNEL_RESET_OPENING
+};
+
+struct qcom_smd_device {
+	struct rpmsg_device rpdev;
+
+	struct qcom_smd_edge *edge;
+};
+
+struct qcom_smd_endpoint {
+	struct rpmsg_endpoint ept;
+
+	struct qcom_smd_channel *qsch;
+};
+
+#define to_smd_device(r)	container_of(r, struct qcom_smd_device, rpdev)
+#define to_smd_edge(d)		container_of(d, struct qcom_smd_edge, dev)
+#define to_smd_endpoint(e)	container_of(e, struct qcom_smd_endpoint, ept)
+
+/**
+ * struct qcom_smd_channel - smd channel struct
+ * @edge:		qcom_smd_edge this channel is living on
+ * @qsept:		reference to a associated smd endpoint
+ * @registered:		flag to indicate if the channel is registered
+ * @name:		name of the channel
+ * @state:		local state of the channel
+ * @remote_state:	remote state of the channel
+ * @state_change_event:	state change event
+ * @info:		byte aligned outgoing/incoming channel info
+ * @info_word:		word aligned outgoing/incoming channel info
+ * @tx_lock:		lock to make writes to the channel mutually exclusive
+ * @fblockread_event:	wakeup event tied to tx fBLOCKREADINTR
+ * @tx_fifo:		pointer to the outgoing ring buffer
+ * @rx_fifo:		pointer to the incoming ring buffer
+ * @fifo_size:		size of each ring buffer
+ * @bounce_buffer:	bounce buffer for reading wrapped packets
+ * @cb:			callback function registered for this channel
+ * @recv_lock:		guard for rx info modifications and cb pointer
+ * @pkt_size:		size of the currently handled packet
+ * @drvdata:		driver private data
+ * @list:		lite entry for @channels in qcom_smd_edge
+ */
+struct qcom_smd_channel {
+	struct qcom_smd_edge *edge;
+
+	struct qcom_smd_endpoint *qsept;
+	bool registered;
+
+	char *name;
+	enum smd_channel_state state;
+	enum smd_channel_state remote_state;
+	wait_queue_head_t state_change_event;
+
+	struct smd_channel_info_pair *info;
+	struct smd_channel_info_word_pair *info_word;
+
+	spinlock_t tx_lock;
+	wait_queue_head_t fblockread_event;
+
+	void *tx_fifo;
+	void *rx_fifo;
+	int fifo_size;
+
+	void *bounce_buffer;
+
+	spinlock_t recv_lock;
+
+	int pkt_size;
+
+	void *drvdata;
+
+	struct list_head list;
+};
+
+/*
+ * Format of the smd_info smem items, for byte aligned channels.
+ */
+struct smd_channel_info {
+	__le32 state;
+	u8  fDSR;
+	u8  fCTS;
+	u8  fCD;
+	u8  fRI;
+	u8  fHEAD;
+	u8  fTAIL;
+	u8  fSTATE;
+	u8  fBLOCKREADINTR;
+	__le32 tail;
+	__le32 head;
+};
+
+struct smd_channel_info_pair {
+	struct smd_channel_info tx;
+	struct smd_channel_info rx;
+};
+
+/*
+ * Format of the smd_info smem items, for word aligned channels.
+ */
+struct smd_channel_info_word {
+	__le32 state;
+	__le32 fDSR;
+	__le32 fCTS;
+	__le32 fCD;
+	__le32 fRI;
+	__le32 fHEAD;
+	__le32 fTAIL;
+	__le32 fSTATE;
+	__le32 fBLOCKREADINTR;
+	__le32 tail;
+	__le32 head;
+};
+
+struct smd_channel_info_word_pair {
+	struct smd_channel_info_word tx;
+	struct smd_channel_info_word rx;
+};
+
+#define GET_RX_CHANNEL_FLAG(channel, param)				     \
+	({								     \
+		BUILD_BUG_ON(sizeof(channel->info->rx.param) != sizeof(u8)); \
+		channel->info_word ?					     \
+			le32_to_cpu(channel->info_word->rx.param) :	     \
+			channel->info->rx.param;			     \
+	})
+
+#define GET_RX_CHANNEL_INFO(channel, param)				      \
+	({								      \
+		BUILD_BUG_ON(sizeof(channel->info->rx.param) != sizeof(u32)); \
+		le32_to_cpu(channel->info_word ?			      \
+			channel->info_word->rx.param :			      \
+			channel->info->rx.param);			      \
+	})
+
+#define SET_RX_CHANNEL_FLAG(channel, param, value)			     \
+	({								     \
+		BUILD_BUG_ON(sizeof(channel->info->rx.param) != sizeof(u8)); \
+		if (channel->info_word)					     \
+			channel->info_word->rx.param = cpu_to_le32(value);   \
+		else							     \
+			channel->info->rx.param = value;		     \
+	})
+
+#define SET_RX_CHANNEL_INFO(channel, param, value)			      \
+	({								      \
+		BUILD_BUG_ON(sizeof(channel->info->rx.param) != sizeof(u32)); \
+		if (channel->info_word)					      \
+			channel->info_word->rx.param = cpu_to_le32(value);    \
+		else							      \
+			channel->info->rx.param = cpu_to_le32(value);	      \
+	})
+
+#define GET_TX_CHANNEL_FLAG(channel, param)				     \
+	({								     \
+		BUILD_BUG_ON(sizeof(channel->info->tx.param) != sizeof(u8)); \
+		channel->info_word ?					     \
+			le32_to_cpu(channel->info_word->tx.param) :          \
+			channel->info->tx.param;			     \
+	})
+
+#define GET_TX_CHANNEL_INFO(channel, param)				      \
+	({								      \
+		BUILD_BUG_ON(sizeof(channel->info->tx.param) != sizeof(u32)); \
+		le32_to_cpu(channel->info_word ?			      \
+			channel->info_word->tx.param :			      \
+			channel->info->tx.param);			      \
+	})
+
+#define SET_TX_CHANNEL_FLAG(channel, param, value)			     \
+	({								     \
+		BUILD_BUG_ON(sizeof(channel->info->tx.param) != sizeof(u8)); \
+		if (channel->info_word)					     \
+			channel->info_word->tx.param = cpu_to_le32(value);   \
+		else							     \
+			channel->info->tx.param = value;		     \
+	})
+
+#define SET_TX_CHANNEL_INFO(channel, param, value)			      \
+	({								      \
+		BUILD_BUG_ON(sizeof(channel->info->tx.param) != sizeof(u32)); \
+		if (channel->info_word)					      \
+			channel->info_word->tx.param = cpu_to_le32(value);   \
+		else							      \
+			channel->info->tx.param = cpu_to_le32(value);	      \
+	})
+
+/**
+ * struct qcom_smd_alloc_entry - channel allocation entry
+ * @name:	channel name
+ * @cid:	channel index
+ * @flags:	channel flags and edge id
+ * @ref_count:	reference count of the channel
+ */
+struct qcom_smd_alloc_entry {
+	u8 name[20];
+	__le32 cid;
+	__le32 flags;
+	__le32 ref_count;
+} __packed;
+
+#define SMD_CHANNEL_FLAGS_EDGE_MASK	0xff
+#define SMD_CHANNEL_FLAGS_STREAM	BIT(8)
+#define SMD_CHANNEL_FLAGS_PACKET	BIT(9)
+
+/*
+ * Each smd packet contains a 20 byte header, with the first 4 being the length
+ * of the packet.
+ */
+#define SMD_PACKET_HEADER_LEN	20
+
+/*
+ * Signal the remote processor associated with 'channel'.
+ */
+static void qcom_smd_signal_channel(struct qcom_smd_channel *channel)
+{
+	struct qcom_smd_edge *edge = channel->edge;
+
+	if (edge->mbox_chan) {
+		/*
+		 * We can ignore a failing mbox_send_message() as the only
+		 * possible cause is that the FIFO in the framework is full of
+		 * other writes to the same bit.
+		 */
+		mbox_send_message(edge->mbox_chan, NULL);
+		mbox_client_txdone(edge->mbox_chan, 0);
+	} else {
+		regmap_write(edge->ipc_regmap, edge->ipc_offset, BIT(edge->ipc_bit));
+	}
+}
+
+/*
+ * Initialize the tx channel info
+ */
+static void qcom_smd_channel_reset(struct qcom_smd_channel *channel)
+{
+	SET_TX_CHANNEL_INFO(channel, state, SMD_CHANNEL_CLOSED);
+	SET_TX_CHANNEL_FLAG(channel, fDSR, 0);
+	SET_TX_CHANNEL_FLAG(channel, fCTS, 0);
+	SET_TX_CHANNEL_FLAG(channel, fCD, 0);
+	SET_TX_CHANNEL_FLAG(channel, fRI, 0);
+	SET_TX_CHANNEL_FLAG(channel, fHEAD, 0);
+	SET_TX_CHANNEL_FLAG(channel, fTAIL, 0);
+	SET_TX_CHANNEL_FLAG(channel, fSTATE, 1);
+	SET_TX_CHANNEL_FLAG(channel, fBLOCKREADINTR, 1);
+	SET_TX_CHANNEL_INFO(channel, head, 0);
+	SET_RX_CHANNEL_INFO(channel, tail, 0);
+
+	qcom_smd_signal_channel(channel);
+
+	channel->state = SMD_CHANNEL_CLOSED;
+	channel->pkt_size = 0;
+}
+
+/*
+ * Set the callback for a channel, with appropriate locking
+ */
+static void qcom_smd_channel_set_callback(struct qcom_smd_channel *channel,
+					  rpmsg_rx_cb_t cb)
+{
+	struct rpmsg_endpoint *ept = &channel->qsept->ept;
+	unsigned long flags;
+
+	spin_lock_irqsave(&channel->recv_lock, flags);
+	ept->cb = cb;
+	spin_unlock_irqrestore(&channel->recv_lock, flags);
+};
+
+/*
+ * Calculate the amount of data available in the rx fifo
+ */
+static size_t qcom_smd_channel_get_rx_avail(struct qcom_smd_channel *channel)
+{
+	unsigned head;
+	unsigned tail;
+
+	head = GET_RX_CHANNEL_INFO(channel, head);
+	tail = GET_RX_CHANNEL_INFO(channel, tail);
+
+	return (head - tail) & (channel->fifo_size - 1);
+}
+
+/*
+ * Set tx channel state and inform the remote processor
+ */
+static void qcom_smd_channel_set_state(struct qcom_smd_channel *channel,
+				       int state)
+{
+	struct qcom_smd_edge *edge = channel->edge;
+	bool is_open = state == SMD_CHANNEL_OPENED;
+
+	if (channel->state == state)
+		return;
+
+	dev_dbg(&edge->dev, "set_state(%s, %d)\n", channel->name, state);
+
+	SET_TX_CHANNEL_FLAG(channel, fDSR, is_open);
+	SET_TX_CHANNEL_FLAG(channel, fCTS, is_open);
+	SET_TX_CHANNEL_FLAG(channel, fCD, is_open);
+
+	SET_TX_CHANNEL_INFO(channel, state, state);
+	SET_TX_CHANNEL_FLAG(channel, fSTATE, 1);
+
+	channel->state = state;
+	qcom_smd_signal_channel(channel);
+}
+
+/*
+ * Copy count bytes of data using 32bit accesses, if that's required.
+ */
+static void smd_copy_to_fifo(void __iomem *dst,
+			     const void *src,
+			     size_t count,
+			     bool word_aligned)
+{
+	if (word_aligned) {
+		__iowrite32_copy(dst, src, count / sizeof(u32));
+	} else {
+		memcpy_toio(dst, src, count);
+	}
+}
+
+/*
+ * Copy count bytes of data using 32bit accesses, if that is required.
+ */
+static void smd_copy_from_fifo(void *dst,
+			       const void __iomem *src,
+			       size_t count,
+			       bool word_aligned)
+{
+	if (word_aligned) {
+		__ioread32_copy(dst, src, count / sizeof(u32));
+	} else {
+		memcpy_fromio(dst, src, count);
+	}
+}
+
+/*
+ * Read count bytes of data from the rx fifo into buf, but don't advance the
+ * tail.
+ */
+static size_t qcom_smd_channel_peek(struct qcom_smd_channel *channel,
+				    void *buf, size_t count)
+{
+	bool word_aligned;
+	unsigned tail;
+	size_t len;
+
+	word_aligned = channel->info_word;
+	tail = GET_RX_CHANNEL_INFO(channel, tail);
+
+	len = min_t(size_t, count, channel->fifo_size - tail);
+	if (len) {
+		smd_copy_from_fifo(buf,
+				   channel->rx_fifo + tail,
+				   len,
+				   word_aligned);
+	}
+
+	if (len != count) {
+		smd_copy_from_fifo(buf + len,
+				   channel->rx_fifo,
+				   count - len,
+				   word_aligned);
+	}
+
+	return count;
+}
+
+/*
+ * Advance the rx tail by count bytes.
+ */
+static void qcom_smd_channel_advance(struct qcom_smd_channel *channel,
+				     size_t count)
+{
+	unsigned tail;
+
+	tail = GET_RX_CHANNEL_INFO(channel, tail);
+	tail += count;
+	tail &= (channel->fifo_size - 1);
+	SET_RX_CHANNEL_INFO(channel, tail, tail);
+}
+
+/*
+ * Read out a single packet from the rx fifo and deliver it to the device
+ */
+static int qcom_smd_channel_recv_single(struct qcom_smd_channel *channel)
+{
+	struct rpmsg_endpoint *ept = &channel->qsept->ept;
+	unsigned tail;
+	size_t len;
+	void *ptr;
+	int ret;
+
+	tail = GET_RX_CHANNEL_INFO(channel, tail);
+
+	/* Use bounce buffer if the data wraps */
+	if (tail + channel->pkt_size >= channel->fifo_size) {
+		ptr = channel->bounce_buffer;
+		len = qcom_smd_channel_peek(channel, ptr, channel->pkt_size);
+	} else {
+		ptr = channel->rx_fifo + tail;
+		len = channel->pkt_size;
+	}
+
+	ret = ept->cb(ept->rpdev, ptr, len, ept->priv, RPMSG_ADDR_ANY);
+	if (ret < 0)
+		return ret;
+
+	/* Only forward the tail if the client consumed the data */
+	qcom_smd_channel_advance(channel, len);
+
+	channel->pkt_size = 0;
+
+	return 0;
+}
+
+/*
+ * Per channel interrupt handling
+ */
+static bool qcom_smd_channel_intr(struct qcom_smd_channel *channel)
+{
+	bool need_state_scan = false;
+	int remote_state;
+	__le32 pktlen;
+	int avail;
+	int ret;
+
+	/* Handle state changes */
+	remote_state = GET_RX_CHANNEL_INFO(channel, state);
+	if (remote_state != channel->remote_state) {
+		channel->remote_state = remote_state;
+		need_state_scan = true;
+
+		wake_up_interruptible_all(&channel->state_change_event);
+	}
+	/* Indicate that we have seen any state change */
+	SET_RX_CHANNEL_FLAG(channel, fSTATE, 0);
+
+	/* Signal waiting qcom_smd_send() about the interrupt */
+	if (!GET_TX_CHANNEL_FLAG(channel, fBLOCKREADINTR))
+		wake_up_interruptible_all(&channel->fblockread_event);
+
+	/* Don't consume any data until we've opened the channel */
+	if (channel->state != SMD_CHANNEL_OPENED)
+		goto out;
+
+	/* Indicate that we've seen the new data */
+	SET_RX_CHANNEL_FLAG(channel, fHEAD, 0);
+
+	/* Consume data */
+	for (;;) {
+		avail = qcom_smd_channel_get_rx_avail(channel);
+
+		if (!channel->pkt_size && avail >= SMD_PACKET_HEADER_LEN) {
+			qcom_smd_channel_peek(channel, &pktlen, sizeof(pktlen));
+			qcom_smd_channel_advance(channel, SMD_PACKET_HEADER_LEN);
+			channel->pkt_size = le32_to_cpu(pktlen);
+		} else if (channel->pkt_size && avail >= channel->pkt_size) {
+			ret = qcom_smd_channel_recv_single(channel);
+			if (ret)
+				break;
+		} else {
+			break;
+		}
+	}
+
+	/* Indicate that we have seen and updated tail */
+	SET_RX_CHANNEL_FLAG(channel, fTAIL, 1);
+
+	/* Signal the remote that we've consumed the data (if requested) */
+	if (!GET_RX_CHANNEL_FLAG(channel, fBLOCKREADINTR)) {
+		/* Ensure ordering of channel info updates */
+		wmb();
+
+		qcom_smd_signal_channel(channel);
+	}
+
+out:
+	return need_state_scan;
+}
+
+/*
+ * The edge interrupts are triggered by the remote processor on state changes,
+ * channel info updates or when new channels are created.
+ */
+static irqreturn_t qcom_smd_edge_intr(int irq, void *data)
+{
+	struct qcom_smd_edge *edge = data;
+	struct qcom_smd_channel *channel;
+	unsigned available;
+	bool kick_scanner = false;
+	bool kick_state = false;
+
+	/*
+	 * Handle state changes or data on each of the channels on this edge
+	 */
+	spin_lock(&edge->channels_lock);
+	list_for_each_entry(channel, &edge->channels, list) {
+		spin_lock(&channel->recv_lock);
+		kick_state |= qcom_smd_channel_intr(channel);
+		spin_unlock(&channel->recv_lock);
+	}
+	spin_unlock(&edge->channels_lock);
+
+	/*
+	 * Creating a new channel requires allocating an smem entry, so we only
+	 * have to scan if the amount of available space in smem have changed
+	 * since last scan.
+	 */
+	available = qcom_smem_get_free_space(edge->remote_pid);
+	if (available != edge->smem_available) {
+		edge->smem_available = available;
+		kick_scanner = true;
+	}
+
+	if (kick_scanner)
+		schedule_work(&edge->scan_work);
+	if (kick_state)
+		schedule_work(&edge->state_work);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * Calculate how much space is available in the tx fifo.
+ */
+static size_t qcom_smd_get_tx_avail(struct qcom_smd_channel *channel)
+{
+	unsigned head;
+	unsigned tail;
+	unsigned mask = channel->fifo_size - 1;
+
+	head = GET_TX_CHANNEL_INFO(channel, head);
+	tail = GET_TX_CHANNEL_INFO(channel, tail);
+
+	return mask - ((head - tail) & mask);
+}
+
+/*
+ * Write count bytes of data into channel, possibly wrapping in the ring buffer
+ */
+static int qcom_smd_write_fifo(struct qcom_smd_channel *channel,
+			       const void *data,
+			       size_t count)
+{
+	bool word_aligned;
+	unsigned head;
+	size_t len;
+
+	word_aligned = channel->info_word;
+	head = GET_TX_CHANNEL_INFO(channel, head);
+
+	len = min_t(size_t, count, channel->fifo_size - head);
+	if (len) {
+		smd_copy_to_fifo(channel->tx_fifo + head,
+				 data,
+				 len,
+				 word_aligned);
+	}
+
+	if (len != count) {
+		smd_copy_to_fifo(channel->tx_fifo,
+				 data + len,
+				 count - len,
+				 word_aligned);
+	}
+
+	head += count;
+	head &= (channel->fifo_size - 1);
+	SET_TX_CHANNEL_INFO(channel, head, head);
+
+	return count;
+}
+
+/**
+ * __qcom_smd_send - write data to smd channel
+ * @channel:	channel handle
+ * @data:	buffer of data to write
+ * @len:	number of bytes to write
+ * @wait:	flag to indicate if write can wait
+ *
+ * This is a blocking write of len bytes into the channel's tx ring buffer and
+ * signal the remote end. It will sleep until there is enough space available
+ * in the tx buffer, utilizing the fBLOCKREADINTR signaling mechanism to avoid
+ * polling.
+ */
+static int __qcom_smd_send(struct qcom_smd_channel *channel, const void *data,
+			   int len, bool wait)
+{
+	__le32 hdr[5] = { cpu_to_le32(len), };
+	int tlen = sizeof(hdr) + len;
+	unsigned long flags;
+	int ret;
+
+	/* Word aligned channels only accept word size aligned data */
+	if (channel->info_word && len % 4)
+		return -EINVAL;
+
+	/* Reject packets that are too big */
+	if (tlen >= channel->fifo_size)
+		return -EINVAL;
+
+	/* Highlight the fact that if we enter the loop below we might sleep */
+	if (wait)
+		might_sleep();
+
+	spin_lock_irqsave(&channel->tx_lock, flags);
+
+	while (qcom_smd_get_tx_avail(channel) < tlen &&
+	       channel->state == SMD_CHANNEL_OPENED) {
+		if (!wait) {
+			ret = -EAGAIN;
+			goto out_unlock;
+		}
+
+		SET_TX_CHANNEL_FLAG(channel, fBLOCKREADINTR, 0);
+
+		/* Wait without holding the tx_lock */
+		spin_unlock_irqrestore(&channel->tx_lock, flags);
+
+		ret = wait_event_interruptible(channel->fblockread_event,
+				       qcom_smd_get_tx_avail(channel) >= tlen ||
+				       channel->state != SMD_CHANNEL_OPENED);
+		if (ret)
+			return ret;
+
+		spin_lock_irqsave(&channel->tx_lock, flags);
+
+		SET_TX_CHANNEL_FLAG(channel, fBLOCKREADINTR, 1);
+	}
+
+	/* Fail if the channel was closed */
+	if (channel->state != SMD_CHANNEL_OPENED) {
+		ret = -EPIPE;
+		goto out_unlock;
+	}
+
+	SET_TX_CHANNEL_FLAG(channel, fTAIL, 0);
+
+	qcom_smd_write_fifo(channel, hdr, sizeof(hdr));
+	qcom_smd_write_fifo(channel, data, len);
+
+	SET_TX_CHANNEL_FLAG(channel, fHEAD, 1);
+
+	/* Ensure ordering of channel info updates */
+	wmb();
+
+	qcom_smd_signal_channel(channel);
+
+out_unlock:
+	spin_unlock_irqrestore(&channel->tx_lock, flags);
+
+	return ret;
+}
+
+/*
+ * Helper for opening a channel
+ */
+static int qcom_smd_channel_open(struct qcom_smd_channel *channel,
+				 rpmsg_rx_cb_t cb)
+{
+	struct qcom_smd_edge *edge = channel->edge;
+	size_t bb_size;
+	int ret;
+
+	/*
+	 * Packets are maximum 4k, but reduce if the fifo is smaller
+	 */
+	bb_size = min(channel->fifo_size, SZ_4K);
+	channel->bounce_buffer = kmalloc(bb_size, GFP_KERNEL);
+	if (!channel->bounce_buffer)
+		return -ENOMEM;
+
+	qcom_smd_channel_set_callback(channel, cb);
+	qcom_smd_channel_set_state(channel, SMD_CHANNEL_OPENING);
+
+	/* Wait for remote to enter opening or opened */
+	ret = wait_event_interruptible_timeout(channel->state_change_event,
+			channel->remote_state == SMD_CHANNEL_OPENING ||
+			channel->remote_state == SMD_CHANNEL_OPENED,
+			HZ);
+	if (!ret) {
+		dev_err(&edge->dev, "remote side did not enter opening state\n");
+		goto out_close_timeout;
+	}
+
+	qcom_smd_channel_set_state(channel, SMD_CHANNEL_OPENED);
+
+	/* Wait for remote to enter opened */
+	ret = wait_event_interruptible_timeout(channel->state_change_event,
+			channel->remote_state == SMD_CHANNEL_OPENED,
+			HZ);
+	if (!ret) {
+		dev_err(&edge->dev, "remote side did not enter open state\n");
+		goto out_close_timeout;
+	}
+
+	return 0;
+
+out_close_timeout:
+	qcom_smd_channel_set_state(channel, SMD_CHANNEL_CLOSED);
+	return -ETIMEDOUT;
+}
+
+/*
+ * Helper for closing and resetting a channel
+ */
+static void qcom_smd_channel_close(struct qcom_smd_channel *channel)
+{
+	qcom_smd_channel_set_callback(channel, NULL);
+
+	kfree(channel->bounce_buffer);
+	channel->bounce_buffer = NULL;
+
+	qcom_smd_channel_set_state(channel, SMD_CHANNEL_CLOSED);
+	qcom_smd_channel_reset(channel);
+}
+
+static struct qcom_smd_channel *
+qcom_smd_find_channel(struct qcom_smd_edge *edge, const char *name)
+{
+	struct qcom_smd_channel *channel;
+	struct qcom_smd_channel *ret = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&edge->channels_lock, flags);
+	list_for_each_entry(channel, &edge->channels, list) {
+		if (!strcmp(channel->name, name)) {
+			ret = channel;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&edge->channels_lock, flags);
+
+	return ret;
+}
+
+static void __ept_release(struct kref *kref)
+{
+	struct rpmsg_endpoint *ept = container_of(kref, struct rpmsg_endpoint,
+						  refcount);
+	kfree(to_smd_endpoint(ept));
+}
+
+static struct rpmsg_endpoint *qcom_smd_create_ept(struct rpmsg_device *rpdev,
+						  rpmsg_rx_cb_t cb, void *priv,
+						  struct rpmsg_channel_info chinfo)
+{
+	struct qcom_smd_endpoint *qsept;
+	struct qcom_smd_channel *channel;
+	struct qcom_smd_device *qsdev = to_smd_device(rpdev);
+	struct qcom_smd_edge *edge = qsdev->edge;
+	struct rpmsg_endpoint *ept;
+	const char *name = chinfo.name;
+	int ret;
+
+	/* Wait up to HZ for the channel to appear */
+	ret = wait_event_interruptible_timeout(edge->new_channel_event,
+			(channel = qcom_smd_find_channel(edge, name)) != NULL,
+			HZ);
+	if (!ret)
+		return NULL;
+
+	if (channel->state != SMD_CHANNEL_CLOSED) {
+		dev_err(&rpdev->dev, "channel %s is busy\n", channel->name);
+		return NULL;
+	}
+
+	qsept = kzalloc(sizeof(*qsept), GFP_KERNEL);
+	if (!qsept)
+		return NULL;
+
+	ept = &qsept->ept;
+
+	kref_init(&ept->refcount);
+
+	ept->rpdev = rpdev;
+	ept->cb = cb;
+	ept->priv = priv;
+	ept->ops = &qcom_smd_endpoint_ops;
+
+	channel->qsept = qsept;
+	qsept->qsch = channel;
+
+	ret = qcom_smd_channel_open(channel, cb);
+	if (ret)
+		goto free_ept;
+
+	return ept;
+
+free_ept:
+	channel->qsept = NULL;
+	kref_put(&ept->refcount, __ept_release);
+	return NULL;
+}
+
+static void qcom_smd_destroy_ept(struct rpmsg_endpoint *ept)
+{
+	struct qcom_smd_endpoint *qsept = to_smd_endpoint(ept);
+	struct qcom_smd_channel *ch = qsept->qsch;
+
+	qcom_smd_channel_close(ch);
+	ch->qsept = NULL;
+	kref_put(&ept->refcount, __ept_release);
+}
+
+static int qcom_smd_send(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct qcom_smd_endpoint *qsept = to_smd_endpoint(ept);
+
+	return __qcom_smd_send(qsept->qsch, data, len, true);
+}
+
+static int qcom_smd_trysend(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct qcom_smd_endpoint *qsept = to_smd_endpoint(ept);
+
+	return __qcom_smd_send(qsept->qsch, data, len, false);
+}
+
+static int qcom_smd_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
+{
+	struct qcom_smd_endpoint *qsept = to_smd_endpoint(ept);
+
+	return __qcom_smd_send(qsept->qsch, data, len, true);
+}
+
+static int qcom_smd_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
+{
+	struct qcom_smd_endpoint *qsept = to_smd_endpoint(ept);
+
+	return __qcom_smd_send(qsept->qsch, data, len, false);
+}
+
+static __poll_t qcom_smd_poll(struct rpmsg_endpoint *ept,
+				  struct file *filp, poll_table *wait)
+{
+	struct qcom_smd_endpoint *qsept = to_smd_endpoint(ept);
+	struct qcom_smd_channel *channel = qsept->qsch;
+	__poll_t mask = 0;
+
+	poll_wait(filp, &channel->fblockread_event, wait);
+
+	if (qcom_smd_get_tx_avail(channel) > 20)
+		mask |= EPOLLOUT | EPOLLWRNORM;
+
+	return mask;
+}
+
+/*
+ * Finds the device_node for the smd child interested in this channel.
+ */
+static struct device_node *qcom_smd_match_channel(struct device_node *edge_node,
+						  const char *channel)
+{
+	struct device_node *child;
+	const char *name;
+	const char *key;
+	int ret;
+
+	for_each_available_child_of_node(edge_node, child) {
+		key = "qcom,smd-channels";
+		ret = of_property_read_string(child, key, &name);
+		if (ret)
+			continue;
+
+		if (strcmp(name, channel) == 0)
+			return child;
+	}
+
+	return NULL;
+}
+
+static int qcom_smd_announce_create(struct rpmsg_device *rpdev)
+{
+	struct qcom_smd_endpoint *qept = to_smd_endpoint(rpdev->ept);
+	struct qcom_smd_channel *channel = qept->qsch;
+	unsigned long flags;
+	bool kick_state;
+
+	spin_lock_irqsave(&channel->recv_lock, flags);
+	kick_state = qcom_smd_channel_intr(channel);
+	spin_unlock_irqrestore(&channel->recv_lock, flags);
+
+	if (kick_state)
+		schedule_work(&channel->edge->state_work);
+
+	return 0;
+}
+
+static const struct rpmsg_device_ops qcom_smd_device_ops = {
+	.create_ept = qcom_smd_create_ept,
+	.announce_create = qcom_smd_announce_create,
+};
+
+static const struct rpmsg_endpoint_ops qcom_smd_endpoint_ops = {
+	.destroy_ept = qcom_smd_destroy_ept,
+	.send = qcom_smd_send,
+	.sendto = qcom_smd_sendto,
+	.trysend = qcom_smd_trysend,
+	.trysendto = qcom_smd_trysendto,
+	.poll = qcom_smd_poll,
+};
+
+static void qcom_smd_release_device(struct device *dev)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+	struct qcom_smd_device *qsdev = to_smd_device(rpdev);
+
+	kfree(qsdev);
+}
+
+/*
+ * Create a smd client device for channel that is being opened.
+ */
+static int qcom_smd_create_device(struct qcom_smd_channel *channel)
+{
+	struct qcom_smd_device *qsdev;
+	struct rpmsg_device *rpdev;
+	struct qcom_smd_edge *edge = channel->edge;
+
+	dev_dbg(&edge->dev, "registering '%s'\n", channel->name);
+
+	qsdev = kzalloc(sizeof(*qsdev), GFP_KERNEL);
+	if (!qsdev)
+		return -ENOMEM;
+
+	/* Link qsdev to our SMD edge */
+	qsdev->edge = edge;
+
+	/* Assign callbacks for rpmsg_device */
+	qsdev->rpdev.ops = &qcom_smd_device_ops;
+
+	/* Assign public information to the rpmsg_device */
+	rpdev = &qsdev->rpdev;
+	strscpy_pad(rpdev->id.name, channel->name, RPMSG_NAME_SIZE);
+	rpdev->src = RPMSG_ADDR_ANY;
+	rpdev->dst = RPMSG_ADDR_ANY;
+
+	rpdev->dev.of_node = qcom_smd_match_channel(edge->of_node, channel->name);
+	rpdev->dev.parent = &edge->dev;
+	rpdev->dev.release = qcom_smd_release_device;
+
+	return rpmsg_register_device(rpdev);
+}
+
+static int qcom_smd_create_chrdev(struct qcom_smd_edge *edge)
+{
+	struct qcom_smd_device *qsdev;
+
+	qsdev = kzalloc(sizeof(*qsdev), GFP_KERNEL);
+	if (!qsdev)
+		return -ENOMEM;
+
+	qsdev->edge = edge;
+	qsdev->rpdev.ops = &qcom_smd_device_ops;
+	qsdev->rpdev.dev.parent = &edge->dev;
+	qsdev->rpdev.dev.release = qcom_smd_release_device;
+
+	return rpmsg_ctrldev_register_device(&qsdev->rpdev);
+}
+
+/*
+ * Allocate the qcom_smd_channel object for a newly found smd channel,
+ * retrieving and validating the smem items involved.
+ */
+static struct qcom_smd_channel *qcom_smd_create_channel(struct qcom_smd_edge *edge,
+							unsigned smem_info_item,
+							unsigned smem_fifo_item,
+							char *name)
+{
+	struct qcom_smd_channel *channel;
+	size_t fifo_size;
+	size_t info_size;
+	void *fifo_base;
+	void *info;
+	int ret;
+
+	channel = kzalloc(sizeof(*channel), GFP_KERNEL);
+	if (!channel)
+		return ERR_PTR(-ENOMEM);
+
+	channel->edge = edge;
+	channel->name = kstrdup(name, GFP_KERNEL);
+	if (!channel->name) {
+		ret = -ENOMEM;
+		goto free_channel;
+	}
+
+	spin_lock_init(&channel->tx_lock);
+	spin_lock_init(&channel->recv_lock);
+	init_waitqueue_head(&channel->fblockread_event);
+	init_waitqueue_head(&channel->state_change_event);
+
+	info = qcom_smem_get(edge->remote_pid, smem_info_item, &info_size);
+	if (IS_ERR(info)) {
+		ret = PTR_ERR(info);
+		goto free_name_and_channel;
+	}
+
+	/*
+	 * Use the size of the item to figure out which channel info struct to
+	 * use.
+	 */
+	if (info_size == 2 * sizeof(struct smd_channel_info_word)) {
+		channel->info_word = info;
+	} else if (info_size == 2 * sizeof(struct smd_channel_info)) {
+		channel->info = info;
+	} else {
+		dev_err(&edge->dev,
+			"channel info of size %zu not supported\n", info_size);
+		ret = -EINVAL;
+		goto free_name_and_channel;
+	}
+
+	fifo_base = qcom_smem_get(edge->remote_pid, smem_fifo_item, &fifo_size);
+	if (IS_ERR(fifo_base)) {
+		ret =  PTR_ERR(fifo_base);
+		goto free_name_and_channel;
+	}
+
+	/* The channel consist of a rx and tx fifo of equal size */
+	fifo_size /= 2;
+
+	dev_dbg(&edge->dev, "new channel '%s' info-size: %zu fifo-size: %zu\n",
+			  name, info_size, fifo_size);
+
+	channel->tx_fifo = fifo_base;
+	channel->rx_fifo = fifo_base + fifo_size;
+	channel->fifo_size = fifo_size;
+
+	qcom_smd_channel_reset(channel);
+
+	return channel;
+
+free_name_and_channel:
+	kfree(channel->name);
+free_channel:
+	kfree(channel);
+
+	return ERR_PTR(ret);
+}
+
+/*
+ * Scans the allocation table for any newly allocated channels, calls
+ * qcom_smd_create_channel() to create representations of these and add
+ * them to the edge's list of channels.
+ */
+static void qcom_channel_scan_worker(struct work_struct *work)
+{
+	struct qcom_smd_edge *edge = container_of(work, struct qcom_smd_edge, scan_work);
+	struct qcom_smd_alloc_entry *alloc_tbl;
+	struct qcom_smd_alloc_entry *entry;
+	struct qcom_smd_channel *channel;
+	unsigned long flags;
+	unsigned fifo_id;
+	unsigned info_id;
+	int tbl;
+	int i;
+	u32 eflags, cid;
+
+	for (tbl = 0; tbl < SMD_ALLOC_TBL_COUNT; tbl++) {
+		alloc_tbl = qcom_smem_get(edge->remote_pid,
+				    smem_items[tbl].alloc_tbl_id, NULL);
+		if (IS_ERR(alloc_tbl))
+			continue;
+
+		for (i = 0; i < SMD_ALLOC_TBL_SIZE; i++) {
+			entry = &alloc_tbl[i];
+			eflags = le32_to_cpu(entry->flags);
+			if (test_bit(i, edge->allocated[tbl]))
+				continue;
+
+			if (entry->ref_count == 0)
+				continue;
+
+			if (!entry->name[0])
+				continue;
+
+			if (!(eflags & SMD_CHANNEL_FLAGS_PACKET))
+				continue;
+
+			if ((eflags & SMD_CHANNEL_FLAGS_EDGE_MASK) != edge->edge_id)
+				continue;
+
+			cid = le32_to_cpu(entry->cid);
+			info_id = smem_items[tbl].info_base_id + cid;
+			fifo_id = smem_items[tbl].fifo_base_id + cid;
+
+			channel = qcom_smd_create_channel(edge, info_id, fifo_id, entry->name);
+			if (IS_ERR(channel))
+				continue;
+
+			spin_lock_irqsave(&edge->channels_lock, flags);
+			list_add(&channel->list, &edge->channels);
+			spin_unlock_irqrestore(&edge->channels_lock, flags);
+
+			dev_dbg(&edge->dev, "new channel found: '%s'\n", channel->name);
+			set_bit(i, edge->allocated[tbl]);
+
+			wake_up_interruptible_all(&edge->new_channel_event);
+		}
+	}
+
+	schedule_work(&edge->state_work);
+}
+
+/*
+ * This per edge worker scans smem for any new channels and register these. It
+ * then scans all registered channels for state changes that should be handled
+ * by creating or destroying smd client devices for the registered channels.
+ *
+ * LOCKING: edge->channels_lock only needs to cover the list operations, as the
+ * worker is killed before any channels are deallocated
+ */
+static void qcom_channel_state_worker(struct work_struct *work)
+{
+	struct qcom_smd_channel *channel;
+	struct qcom_smd_edge *edge = container_of(work,
+						  struct qcom_smd_edge,
+						  state_work);
+	struct rpmsg_channel_info chinfo;
+	unsigned remote_state;
+	unsigned long flags;
+
+	/*
+	 * Register a device for any closed channel where the remote processor
+	 * is showing interest in opening the channel.
+	 */
+	spin_lock_irqsave(&edge->channels_lock, flags);
+	list_for_each_entry(channel, &edge->channels, list) {
+		if (channel->state != SMD_CHANNEL_CLOSED)
+			continue;
+
+		/*
+		 * Always open rpm_requests, even when already opened which is
+		 * required on some SoCs like msm8953.
+		 */
+		remote_state = GET_RX_CHANNEL_INFO(channel, state);
+		if (remote_state != SMD_CHANNEL_OPENING &&
+		    remote_state != SMD_CHANNEL_OPENED &&
+		    strcmp(channel->name, "rpm_requests"))
+			continue;
+
+		if (channel->registered)
+			continue;
+
+		spin_unlock_irqrestore(&edge->channels_lock, flags);
+		qcom_smd_create_device(channel);
+		spin_lock_irqsave(&edge->channels_lock, flags);
+		channel->registered = true;
+	}
+
+	/*
+	 * Unregister the device for any channel that is opened where the
+	 * remote processor is closing the channel.
+	 */
+	list_for_each_entry(channel, &edge->channels, list) {
+		if (channel->state != SMD_CHANNEL_OPENING &&
+		    channel->state != SMD_CHANNEL_OPENED)
+			continue;
+
+		remote_state = GET_RX_CHANNEL_INFO(channel, state);
+		if (remote_state == SMD_CHANNEL_OPENING ||
+		    remote_state == SMD_CHANNEL_OPENED)
+			continue;
+
+		spin_unlock_irqrestore(&edge->channels_lock, flags);
+
+		strscpy_pad(chinfo.name, channel->name, sizeof(chinfo.name));
+		chinfo.src = RPMSG_ADDR_ANY;
+		chinfo.dst = RPMSG_ADDR_ANY;
+		rpmsg_unregister_device(&edge->dev, &chinfo);
+		channel->registered = false;
+		spin_lock_irqsave(&edge->channels_lock, flags);
+	}
+	spin_unlock_irqrestore(&edge->channels_lock, flags);
+}
+
+/*
+ * Parses an of_node describing an edge.
+ */
+static int qcom_smd_parse_edge(struct device *dev,
+			       struct device_node *node,
+			       struct qcom_smd_edge *edge)
+{
+	struct device_node *syscon_np;
+	const char *key;
+	int irq;
+	int ret;
+
+	INIT_LIST_HEAD(&edge->channels);
+	spin_lock_init(&edge->channels_lock);
+
+	INIT_WORK(&edge->scan_work, qcom_channel_scan_worker);
+	INIT_WORK(&edge->state_work, qcom_channel_state_worker);
+
+	edge->of_node = of_node_get(node);
+
+	key = "qcom,smd-edge";
+	ret = of_property_read_u32(node, key, &edge->edge_id);
+	if (ret) {
+		dev_err(dev, "edge missing %s property\n", key);
+		goto put_node;
+	}
+
+	edge->remote_pid = QCOM_SMEM_HOST_ANY;
+	key = "qcom,remote-pid";
+	of_property_read_u32(node, key, &edge->remote_pid);
+
+	edge->mbox_client.dev = dev;
+	edge->mbox_client.knows_txdone = true;
+	edge->mbox_chan = mbox_request_channel(&edge->mbox_client, 0);
+	if (IS_ERR(edge->mbox_chan)) {
+		if (PTR_ERR(edge->mbox_chan) != -ENODEV) {
+			ret = PTR_ERR(edge->mbox_chan);
+			goto put_node;
+		}
+
+		edge->mbox_chan = NULL;
+
+		syscon_np = of_parse_phandle(node, "qcom,ipc", 0);
+		if (!syscon_np) {
+			dev_err(dev, "no qcom,ipc node\n");
+			ret = -ENODEV;
+			goto put_node;
+		}
+
+		edge->ipc_regmap = syscon_node_to_regmap(syscon_np);
+		of_node_put(syscon_np);
+		if (IS_ERR(edge->ipc_regmap)) {
+			ret = PTR_ERR(edge->ipc_regmap);
+			goto put_node;
+		}
+
+		key = "qcom,ipc";
+		ret = of_property_read_u32_index(node, key, 1, &edge->ipc_offset);
+		if (ret < 0) {
+			dev_err(dev, "no offset in %s\n", key);
+			goto put_node;
+		}
+
+		ret = of_property_read_u32_index(node, key, 2, &edge->ipc_bit);
+		if (ret < 0) {
+			dev_err(dev, "no bit in %s\n", key);
+			goto put_node;
+		}
+	}
+
+	ret = of_property_read_string(node, "label", &edge->name);
+	if (ret < 0)
+		edge->name = node->name;
+
+	irq = irq_of_parse_and_map(node, 0);
+	if (!irq) {
+		dev_err(dev, "required smd interrupt missing\n");
+		ret = -EINVAL;
+		goto put_node;
+	}
+
+	ret = devm_request_irq(dev, irq,
+			       qcom_smd_edge_intr, IRQF_TRIGGER_RISING,
+			       node->name, edge);
+	if (ret) {
+		dev_err(dev, "failed to request smd irq\n");
+		goto put_node;
+	}
+
+	edge->irq = irq;
+
+	return 0;
+
+put_node:
+	of_node_put(node);
+	edge->of_node = NULL;
+
+	return ret;
+}
+
+/*
+ * Release function for an edge.
+  * Reset the state of each associated channel and free the edge context.
+ */
+static void qcom_smd_edge_release(struct device *dev)
+{
+	struct qcom_smd_channel *channel, *tmp;
+	struct qcom_smd_edge *edge = to_smd_edge(dev);
+
+	list_for_each_entry_safe(channel, tmp, &edge->channels, list) {
+		list_del(&channel->list);
+		kfree(channel->name);
+		kfree(channel);
+	}
+
+	kfree(edge);
+}
+
+static ssize_t rpmsg_name_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct qcom_smd_edge *edge = to_smd_edge(dev);
+
+	return sprintf(buf, "%s\n", edge->name);
+}
+static DEVICE_ATTR_RO(rpmsg_name);
+
+static struct attribute *qcom_smd_edge_attrs[] = {
+	&dev_attr_rpmsg_name.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(qcom_smd_edge);
+
+/**
+ * qcom_smd_register_edge() - register an edge based on an device_node
+ * @parent:    parent device for the edge
+ * @node:      device_node describing the edge
+ *
+ * Return: an edge reference, or negative ERR_PTR() on failure.
+ */
+struct qcom_smd_edge *qcom_smd_register_edge(struct device *parent,
+					     struct device_node *node)
+{
+	struct qcom_smd_edge *edge;
+	int ret;
+
+	edge = kzalloc(sizeof(*edge), GFP_KERNEL);
+	if (!edge)
+		return ERR_PTR(-ENOMEM);
+
+	init_waitqueue_head(&edge->new_channel_event);
+
+	edge->dev.parent = parent;
+	edge->dev.release = qcom_smd_edge_release;
+	edge->dev.of_node = node;
+	edge->dev.groups = qcom_smd_edge_groups;
+	dev_set_name(&edge->dev, "%s:%pOFn", dev_name(parent), node);
+	ret = device_register(&edge->dev);
+	if (ret) {
+		pr_err("failed to register smd edge\n");
+		put_device(&edge->dev);
+		return ERR_PTR(ret);
+	}
+
+	ret = qcom_smd_parse_edge(&edge->dev, node, edge);
+	if (ret) {
+		dev_err(&edge->dev, "failed to parse smd edge\n");
+		goto unregister_dev;
+	}
+
+	ret = qcom_smd_create_chrdev(edge);
+	if (ret) {
+		dev_err(&edge->dev, "failed to register chrdev for edge\n");
+		goto unregister_dev;
+	}
+
+	schedule_work(&edge->scan_work);
+
+	return edge;
+
+unregister_dev:
+	if (!IS_ERR_OR_NULL(edge->mbox_chan))
+		mbox_free_channel(edge->mbox_chan);
+
+	device_unregister(&edge->dev);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(qcom_smd_register_edge);
+
+static int qcom_smd_remove_device(struct device *dev, void *data)
+{
+	device_unregister(dev);
+
+	return 0;
+}
+
+/**
+ * qcom_smd_unregister_edge() - release an edge and its children
+ * @edge:      edge reference acquired from qcom_smd_register_edge
+ */
+int qcom_smd_unregister_edge(struct qcom_smd_edge *edge)
+{
+	int ret;
+
+	disable_irq(edge->irq);
+	cancel_work_sync(&edge->scan_work);
+	cancel_work_sync(&edge->state_work);
+
+	ret = device_for_each_child(&edge->dev, NULL, qcom_smd_remove_device);
+	if (ret)
+		dev_warn(&edge->dev, "can't remove smd device: %d\n", ret);
+
+	mbox_free_channel(edge->mbox_chan);
+	device_unregister(&edge->dev);
+
+	return 0;
+}
+EXPORT_SYMBOL(qcom_smd_unregister_edge);
+
+static int qcom_smd_probe(struct platform_device *pdev)
+{
+	struct device_node *node;
+	void *p;
+
+	/* Wait for smem */
+	p = qcom_smem_get(QCOM_SMEM_HOST_ANY, smem_items[0].alloc_tbl_id, NULL);
+	if (PTR_ERR(p) == -EPROBE_DEFER)
+		return PTR_ERR(p);
+
+	for_each_available_child_of_node(pdev->dev.of_node, node)
+		qcom_smd_register_edge(&pdev->dev, node);
+
+	return 0;
+}
+
+static int qcom_smd_remove_edge(struct device *dev, void *data)
+{
+	struct qcom_smd_edge *edge = to_smd_edge(dev);
+
+	return qcom_smd_unregister_edge(edge);
+}
+
+/*
+ * Shut down all smd clients by making sure that each edge stops processing
+ * events and scanning for new channels, then call destroy on the devices.
+ */
+static int qcom_smd_remove(struct platform_device *pdev)
+{
+	int ret;
+
+	ret = device_for_each_child(&pdev->dev, NULL, qcom_smd_remove_edge);
+	if (ret)
+		dev_warn(&pdev->dev, "can't remove smd device: %d\n", ret);
+
+	return ret;
+}
+
+static const struct of_device_id qcom_smd_of_match[] = {
+	{ .compatible = "qcom,smd" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, qcom_smd_of_match);
+
+static struct platform_driver qcom_smd_driver = {
+	.probe = qcom_smd_probe,
+	.remove = qcom_smd_remove,
+	.driver = {
+		.name = "qcom-smd",
+		.of_match_table = qcom_smd_of_match,
+	},
+};
+
+static int __init qcom_smd_init(void)
+{
+	return platform_driver_register(&qcom_smd_driver);
+}
+arch_initcall(qcom_smd_init);
+
+static void __exit qcom_smd_exit(void)
+{
+	platform_driver_unregister(&qcom_smd_driver);
+}
+module_exit(qcom_smd_exit);
+
+MODULE_AUTHOR("Bjorn Andersson <bjorn.andersson@sonymobile.com>");
+MODULE_DESCRIPTION("Qualcomm Shared Memory Driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
new file mode 100644
index 000000000..3e0b8f349
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -0,0 +1,519 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022, STMicroelectronics
+ * Copyright (c) 2016, Linaro Ltd.
+ * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
+ * Copyright (c) 2012, PetaLogix
+ * Copyright (c) 2011, Texas Instruments, Inc.
+ * Copyright (c) 2011, Google, Inc.
+ *
+ * Based on rpmsg performance statistics driver by Michal Simek, which in turn
+ * was based on TI & Google OMX rpmsg driver.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/idr.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/rpmsg.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <uapi/linux/rpmsg.h>
+
+#include "rpmsg_char.h"
+#include "rpmsg_internal.h"
+
+#define RPMSG_DEV_MAX	(MINORMASK + 1)
+
+static dev_t rpmsg_major;
+
+static DEFINE_IDA(rpmsg_ept_ida);
+static DEFINE_IDA(rpmsg_minor_ida);
+
+#define dev_to_eptdev(dev) container_of(dev, struct rpmsg_eptdev, dev)
+#define cdev_to_eptdev(i_cdev) container_of(i_cdev, struct rpmsg_eptdev, cdev)
+
+/**
+ * struct rpmsg_eptdev - endpoint device context
+ * @dev:	endpoint device
+ * @cdev:	cdev for the endpoint device
+ * @rpdev:	underlaying rpmsg device
+ * @chinfo:	info used to open the endpoint
+ * @ept_lock:	synchronization of @ept modifications
+ * @ept:	rpmsg endpoint reference, when open
+ * @queue_lock:	synchronization of @queue operations
+ * @queue:	incoming message queue
+ * @readq:	wait object for incoming queue
+ * @default_ept: set to channel default endpoint if the default endpoint should be re-used
+ *              on device open to prevent endpoint address update.
+ */
+struct rpmsg_eptdev {
+	struct device dev;
+	struct cdev cdev;
+
+	struct rpmsg_device *rpdev;
+	struct rpmsg_channel_info chinfo;
+
+	struct mutex ept_lock;
+	struct rpmsg_endpoint *ept;
+	struct rpmsg_endpoint *default_ept;
+
+	spinlock_t queue_lock;
+	struct sk_buff_head queue;
+	wait_queue_head_t readq;
+
+};
+
+int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
+{
+	struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
+
+	mutex_lock(&eptdev->ept_lock);
+	if (eptdev->ept) {
+		/* The default endpoint is released by the rpmsg core */
+		if (!eptdev->default_ept)
+			rpmsg_destroy_ept(eptdev->ept);
+		eptdev->ept = NULL;
+	}
+	mutex_unlock(&eptdev->ept_lock);
+
+	/* wake up any blocked readers */
+	wake_up_interruptible(&eptdev->readq);
+
+	cdev_device_del(&eptdev->cdev, &eptdev->dev);
+	put_device(&eptdev->dev);
+
+	return 0;
+}
+EXPORT_SYMBOL(rpmsg_chrdev_eptdev_destroy);
+
+static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
+			void *priv, u32 addr)
+{
+	struct rpmsg_eptdev *eptdev = priv;
+	struct sk_buff *skb;
+
+	skb = alloc_skb(len, GFP_ATOMIC);
+	if (!skb)
+		return -ENOMEM;
+
+	skb_put_data(skb, buf, len);
+
+	spin_lock(&eptdev->queue_lock);
+	skb_queue_tail(&eptdev->queue, skb);
+	spin_unlock(&eptdev->queue_lock);
+
+	/* wake up any blocking processes, waiting for new data */
+	wake_up_interruptible(&eptdev->readq);
+
+	return 0;
+}
+
+static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
+{
+	struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
+	struct rpmsg_endpoint *ept;
+	struct rpmsg_device *rpdev = eptdev->rpdev;
+	struct device *dev = &eptdev->dev;
+
+	mutex_lock(&eptdev->ept_lock);
+	if (eptdev->ept) {
+		mutex_unlock(&eptdev->ept_lock);
+		return -EBUSY;
+	}
+
+	get_device(dev);
+
+	/*
+	 * If the default_ept is set, the rpmsg device default endpoint is used.
+	 * Else a new endpoint is created on open that will be destroyed on release.
+	 */
+	if (eptdev->default_ept)
+		ept = eptdev->default_ept;
+	else
+		ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo);
+
+	if (!ept) {
+		dev_err(dev, "failed to open %s\n", eptdev->chinfo.name);
+		put_device(dev);
+		mutex_unlock(&eptdev->ept_lock);
+		return -EINVAL;
+	}
+
+	eptdev->ept = ept;
+	filp->private_data = eptdev;
+	mutex_unlock(&eptdev->ept_lock);
+
+	return 0;
+}
+
+static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
+{
+	struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
+	struct device *dev = &eptdev->dev;
+
+	/* Close the endpoint, if it's not already destroyed by the parent */
+	mutex_lock(&eptdev->ept_lock);
+	if (eptdev->ept) {
+		if (!eptdev->default_ept)
+			rpmsg_destroy_ept(eptdev->ept);
+		eptdev->ept = NULL;
+	}
+	mutex_unlock(&eptdev->ept_lock);
+
+	/* Discard all SKBs */
+	skb_queue_purge(&eptdev->queue);
+
+	put_device(dev);
+
+	return 0;
+}
+
+static ssize_t rpmsg_eptdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct file *filp = iocb->ki_filp;
+	struct rpmsg_eptdev *eptdev = filp->private_data;
+	unsigned long flags;
+	struct sk_buff *skb;
+	int use;
+
+	if (!eptdev->ept)
+		return -EPIPE;
+
+	spin_lock_irqsave(&eptdev->queue_lock, flags);
+
+	/* Wait for data in the queue */
+	if (skb_queue_empty(&eptdev->queue)) {
+		spin_unlock_irqrestore(&eptdev->queue_lock, flags);
+
+		if (filp->f_flags & O_NONBLOCK)
+			return -EAGAIN;
+
+		/* Wait until we get data or the endpoint goes away */
+		if (wait_event_interruptible(eptdev->readq,
+					     !skb_queue_empty(&eptdev->queue) ||
+					     !eptdev->ept))
+			return -ERESTARTSYS;
+
+		/* We lost the endpoint while waiting */
+		if (!eptdev->ept)
+			return -EPIPE;
+
+		spin_lock_irqsave(&eptdev->queue_lock, flags);
+	}
+
+	skb = skb_dequeue(&eptdev->queue);
+	spin_unlock_irqrestore(&eptdev->queue_lock, flags);
+	if (!skb)
+		return -EFAULT;
+
+	use = min_t(size_t, iov_iter_count(to), skb->len);
+	if (copy_to_iter(skb->data, use, to) != use)
+		use = -EFAULT;
+
+	kfree_skb(skb);
+
+	return use;
+}
+
+static ssize_t rpmsg_eptdev_write_iter(struct kiocb *iocb,
+				       struct iov_iter *from)
+{
+	struct file *filp = iocb->ki_filp;
+	struct rpmsg_eptdev *eptdev = filp->private_data;
+	size_t len = iov_iter_count(from);
+	void *kbuf;
+	int ret;
+
+	kbuf = kzalloc(len, GFP_KERNEL);
+	if (!kbuf)
+		return -ENOMEM;
+
+	if (!copy_from_iter_full(kbuf, len, from)) {
+		ret = -EFAULT;
+		goto free_kbuf;
+	}
+
+	if (mutex_lock_interruptible(&eptdev->ept_lock)) {
+		ret = -ERESTARTSYS;
+		goto free_kbuf;
+	}
+
+	if (!eptdev->ept) {
+		ret = -EPIPE;
+		goto unlock_eptdev;
+	}
+
+	if (filp->f_flags & O_NONBLOCK) {
+		ret = rpmsg_trysendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst);
+		if (ret == -ENOMEM)
+			ret = -EAGAIN;
+	} else {
+		ret = rpmsg_sendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst);
+	}
+
+unlock_eptdev:
+	mutex_unlock(&eptdev->ept_lock);
+
+free_kbuf:
+	kfree(kbuf);
+	return ret < 0 ? ret : len;
+}
+
+static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
+{
+	struct rpmsg_eptdev *eptdev = filp->private_data;
+	__poll_t mask = 0;
+
+	if (!eptdev->ept)
+		return EPOLLERR;
+
+	poll_wait(filp, &eptdev->readq, wait);
+
+	if (!skb_queue_empty(&eptdev->queue))
+		mask |= EPOLLIN | EPOLLRDNORM;
+
+	mask |= rpmsg_poll(eptdev->ept, filp, wait);
+
+	return mask;
+}
+
+static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
+			       unsigned long arg)
+{
+	struct rpmsg_eptdev *eptdev = fp->private_data;
+
+	if (cmd != RPMSG_DESTROY_EPT_IOCTL)
+		return -EINVAL;
+
+	/* Don't allow to destroy a default endpoint. */
+	if (eptdev->default_ept)
+		return -EINVAL;
+
+	return rpmsg_chrdev_eptdev_destroy(&eptdev->dev, NULL);
+}
+
+static const struct file_operations rpmsg_eptdev_fops = {
+	.owner = THIS_MODULE,
+	.open = rpmsg_eptdev_open,
+	.release = rpmsg_eptdev_release,
+	.read_iter = rpmsg_eptdev_read_iter,
+	.write_iter = rpmsg_eptdev_write_iter,
+	.poll = rpmsg_eptdev_poll,
+	.unlocked_ioctl = rpmsg_eptdev_ioctl,
+	.compat_ioctl = compat_ptr_ioctl,
+};
+
+static ssize_t name_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%s\n", eptdev->chinfo.name);
+}
+static DEVICE_ATTR_RO(name);
+
+static ssize_t src_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", eptdev->chinfo.src);
+}
+static DEVICE_ATTR_RO(src);
+
+static ssize_t dst_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", eptdev->chinfo.dst);
+}
+static DEVICE_ATTR_RO(dst);
+
+static struct attribute *rpmsg_eptdev_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_src.attr,
+	&dev_attr_dst.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(rpmsg_eptdev);
+
+static void rpmsg_eptdev_release_device(struct device *dev)
+{
+	struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
+
+	ida_simple_remove(&rpmsg_ept_ida, dev->id);
+	ida_simple_remove(&rpmsg_minor_ida, MINOR(eptdev->dev.devt));
+	kfree(eptdev);
+}
+
+static struct rpmsg_eptdev *rpmsg_chrdev_eptdev_alloc(struct rpmsg_device *rpdev,
+						      struct device *parent)
+{
+	struct rpmsg_eptdev *eptdev;
+	struct device *dev;
+
+	eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL);
+	if (!eptdev)
+		return ERR_PTR(-ENOMEM);
+
+	dev = &eptdev->dev;
+	eptdev->rpdev = rpdev;
+
+	mutex_init(&eptdev->ept_lock);
+	spin_lock_init(&eptdev->queue_lock);
+	skb_queue_head_init(&eptdev->queue);
+	init_waitqueue_head(&eptdev->readq);
+
+	device_initialize(dev);
+	dev->class = rpmsg_class;
+	dev->parent = parent;
+	dev->groups = rpmsg_eptdev_groups;
+	dev_set_drvdata(dev, eptdev);
+
+	cdev_init(&eptdev->cdev, &rpmsg_eptdev_fops);
+	eptdev->cdev.owner = THIS_MODULE;
+
+	return eptdev;
+}
+
+static int rpmsg_chrdev_eptdev_add(struct rpmsg_eptdev *eptdev, struct rpmsg_channel_info chinfo)
+{
+	struct device *dev = &eptdev->dev;
+	int ret;
+
+	eptdev->chinfo = chinfo;
+
+	ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
+	if (ret < 0)
+		goto free_eptdev;
+	dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
+
+	ret = ida_simple_get(&rpmsg_ept_ida, 0, 0, GFP_KERNEL);
+	if (ret < 0)
+		goto free_minor_ida;
+	dev->id = ret;
+	dev_set_name(dev, "rpmsg%d", ret);
+
+	ret = cdev_device_add(&eptdev->cdev, &eptdev->dev);
+	if (ret)
+		goto free_ept_ida;
+
+	/* We can now rely on the release function for cleanup */
+	dev->release = rpmsg_eptdev_release_device;
+
+	return ret;
+
+free_ept_ida:
+	ida_simple_remove(&rpmsg_ept_ida, dev->id);
+free_minor_ida:
+	ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
+free_eptdev:
+	put_device(dev);
+	kfree(eptdev);
+
+	return ret;
+}
+
+int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent,
+			       struct rpmsg_channel_info chinfo)
+{
+	struct rpmsg_eptdev *eptdev;
+
+	eptdev = rpmsg_chrdev_eptdev_alloc(rpdev, parent);
+	if (IS_ERR(eptdev))
+		return PTR_ERR(eptdev);
+
+	return rpmsg_chrdev_eptdev_add(eptdev, chinfo);
+}
+EXPORT_SYMBOL(rpmsg_chrdev_eptdev_create);
+
+static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
+{
+	struct rpmsg_channel_info chinfo;
+	struct rpmsg_eptdev *eptdev;
+	struct device *dev = &rpdev->dev;
+
+	memcpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
+	chinfo.src = rpdev->src;
+	chinfo.dst = rpdev->dst;
+
+	eptdev = rpmsg_chrdev_eptdev_alloc(rpdev, dev);
+	if (IS_ERR(eptdev))
+		return PTR_ERR(eptdev);
+
+	/* Set the default_ept to the rpmsg device endpoint */
+	eptdev->default_ept = rpdev->ept;
+
+	/*
+	 * The rpmsg_ept_cb uses *priv parameter to get its rpmsg_eptdev context.
+	 * Storedit in default_ept *priv field.
+	 */
+	eptdev->default_ept->priv = eptdev;
+
+	return rpmsg_chrdev_eptdev_add(eptdev, chinfo);
+}
+
+static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
+{
+	int ret;
+
+	ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_eptdev_destroy);
+	if (ret)
+		dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret);
+}
+
+static struct rpmsg_device_id rpmsg_chrdev_id_table[] = {
+	{ .name	= "rpmsg-raw" },
+	{ },
+};
+
+static struct rpmsg_driver rpmsg_chrdev_driver = {
+	.probe = rpmsg_chrdev_probe,
+	.remove = rpmsg_chrdev_remove,
+	.callback = rpmsg_ept_cb,
+	.id_table = rpmsg_chrdev_id_table,
+	.drv.name = "rpmsg_chrdev",
+};
+
+static int rpmsg_chrdev_init(void)
+{
+	int ret;
+
+	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_char");
+	if (ret < 0) {
+		pr_err("failed to allocate char dev region\n");
+		return ret;
+	}
+
+	ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
+	if (ret < 0) {
+		pr_err("rpmsg: failed to register rpmsg raw driver\n");
+		goto free_region;
+	}
+
+	return 0;
+
+free_region:
+	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
+
+	return ret;
+}
+postcore_initcall(rpmsg_chrdev_init);
+
+static void rpmsg_chrdev_exit(void)
+{
+	unregister_rpmsg_driver(&rpmsg_chrdev_driver);
+	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
+}
+module_exit(rpmsg_chrdev_exit);
+
+MODULE_ALIAS("rpmsg:rpmsg_chrdev");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/rpmsg/rpmsg_char.h b/drivers/rpmsg/rpmsg_char.h
new file mode 100644
index 000000000..117d9cbc5
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_char.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2022, STMicroelectronics
+ */
+
+#ifndef __RPMSG_CHRDEV_H__
+#define __RPMSG_CHRDEV_H__
+
+#if IS_ENABLED(CONFIG_RPMSG_CHAR)
+/**
+ * rpmsg_chrdev_eptdev_create() - register char device based on an endpoint
+ * @rpdev:  prepared rpdev to be used for creating endpoints
+ * @parent: parent device
+ * @chinfo: associated endpoint channel information.
+ *
+ * This function create a new rpmsg char endpoint device to instantiate a new
+ * endpoint based on chinfo information.
+ */
+int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent,
+			       struct rpmsg_channel_info chinfo);
+
+/**
+ * rpmsg_chrdev_eptdev_destroy() - destroy created char device endpoint.
+ * @data: private data associated to the endpoint device
+ *
+ * This function destroys a rpmsg char endpoint device created by the RPMSG_DESTROY_EPT_IOCTL
+ * control.
+ */
+int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data);
+
+#else  /*IS_ENABLED(CONFIG_RPMSG_CHAR) */
+
+static inline int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent,
+					     struct rpmsg_channel_info chinfo)
+{
+	return -ENXIO;
+}
+
+static inline int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
+{
+	return -ENXIO;
+}
+
+#endif /*IS_ENABLED(CONFIG_RPMSG_CHAR) */
+
+#endif /*__RPMSG_CHRDEV_H__ */
diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
new file mode 100644
index 000000000..d6dde00ef
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_core.c
@@ -0,0 +1,720 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * remote processor messaging bus
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Ohad Ben-Cohen <ohad@wizery.com>
+ * Brian Swetland <swetland@google.com>
+ */
+
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/rpmsg.h>
+#include <linux/of_device.h>
+#include <linux/pm_domain.h>
+#include <linux/slab.h>
+
+#include "rpmsg_internal.h"
+
+struct class *rpmsg_class;
+EXPORT_SYMBOL(rpmsg_class);
+
+/**
+ * rpmsg_create_channel() - create a new rpmsg channel
+ * using its name and address info.
+ * @rpdev: rpmsg device
+ * @chinfo: channel_info to bind
+ *
+ * Return: a pointer to the new rpmsg device on success, or NULL on error.
+ */
+struct rpmsg_device *rpmsg_create_channel(struct rpmsg_device *rpdev,
+					  struct rpmsg_channel_info *chinfo)
+{
+	if (WARN_ON(!rpdev))
+		return NULL;
+	if (!rpdev->ops || !rpdev->ops->create_channel) {
+		dev_err(&rpdev->dev, "no create_channel ops found\n");
+		return NULL;
+	}
+
+	return rpdev->ops->create_channel(rpdev, chinfo);
+}
+EXPORT_SYMBOL(rpmsg_create_channel);
+
+/**
+ * rpmsg_release_channel() - release a rpmsg channel
+ * using its name and address info.
+ * @rpdev: rpmsg device
+ * @chinfo: channel_info to bind
+ *
+ * Return: 0 on success or an appropriate error value.
+ */
+int rpmsg_release_channel(struct rpmsg_device *rpdev,
+			  struct rpmsg_channel_info *chinfo)
+{
+	if (WARN_ON(!rpdev))
+		return -EINVAL;
+	if (!rpdev->ops || !rpdev->ops->release_channel) {
+		dev_err(&rpdev->dev, "no release_channel ops found\n");
+		return -ENXIO;
+	}
+
+	return rpdev->ops->release_channel(rpdev, chinfo);
+}
+EXPORT_SYMBOL(rpmsg_release_channel);
+
+/**
+ * rpmsg_create_ept() - create a new rpmsg_endpoint
+ * @rpdev: rpmsg channel device
+ * @cb: rx callback handler
+ * @priv: private data for the driver's use
+ * @chinfo: channel_info with the local rpmsg address to bind with @cb
+ *
+ * Every rpmsg address in the system is bound to an rx callback (so when
+ * inbound messages arrive, they are dispatched by the rpmsg bus using the
+ * appropriate callback handler) by means of an rpmsg_endpoint struct.
+ *
+ * This function allows drivers to create such an endpoint, and by that,
+ * bind a callback, and possibly some private data too, to an rpmsg address
+ * (either one that is known in advance, or one that will be dynamically
+ * assigned for them).
+ *
+ * Simple rpmsg drivers need not call rpmsg_create_ept, because an endpoint
+ * is already created for them when they are probed by the rpmsg bus
+ * (using the rx callback provided when they registered to the rpmsg bus).
+ *
+ * So things should just work for simple drivers: they already have an
+ * endpoint, their rx callback is bound to their rpmsg address, and when
+ * relevant inbound messages arrive (i.e. messages which their dst address
+ * equals to the src address of their rpmsg channel), the driver's handler
+ * is invoked to process it.
+ *
+ * That said, more complicated drivers might need to allocate
+ * additional rpmsg addresses, and bind them to different rx callbacks.
+ * To accomplish that, those drivers need to call this function.
+ *
+ * Drivers should provide their @rpdev channel (so the new endpoint would belong
+ * to the same remote processor their channel belongs to), an rx callback
+ * function, an optional private data (which is provided back when the
+ * rx callback is invoked), and an address they want to bind with the
+ * callback. If @addr is RPMSG_ADDR_ANY, then rpmsg_create_ept will
+ * dynamically assign them an available rpmsg address (drivers should have
+ * a very good reason why not to always use RPMSG_ADDR_ANY here).
+ *
+ * Return: a pointer to the endpoint on success, or NULL on error.
+ */
+struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev,
+					rpmsg_rx_cb_t cb, void *priv,
+					struct rpmsg_channel_info chinfo)
+{
+	if (WARN_ON(!rpdev))
+		return NULL;
+
+	return rpdev->ops->create_ept(rpdev, cb, priv, chinfo);
+}
+EXPORT_SYMBOL(rpmsg_create_ept);
+
+/**
+ * rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
+ * @ept: endpoing to destroy
+ *
+ * Should be used by drivers to destroy an rpmsg endpoint previously
+ * created with rpmsg_create_ept(). As with other types of "free" NULL
+ * is a valid parameter.
+ */
+void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
+{
+	if (ept && ept->ops)
+		ept->ops->destroy_ept(ept);
+}
+EXPORT_SYMBOL(rpmsg_destroy_ept);
+
+/**
+ * rpmsg_send() - send a message across to the remote processor
+ * @ept: the rpmsg endpoint
+ * @data: payload of message
+ * @len: length of payload
+ *
+ * This function sends @data of length @len on the @ept endpoint.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to, using @ept's address and its associated rpmsg
+ * device destination addresses.
+ * In case there are no TX buffers available, the function will block until
+ * one becomes available, or a timeout of 15 seconds elapses. When the latter
+ * happens, -ERESTARTSYS is returned.
+ *
+ * Can only be called from process context (for now).
+ *
+ * Return: 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->send)
+		return -ENXIO;
+
+	return ept->ops->send(ept, data, len);
+}
+EXPORT_SYMBOL(rpmsg_send);
+
+/**
+ * rpmsg_sendto() - send a message across to the remote processor, specify dst
+ * @ept: the rpmsg endpoint
+ * @data: payload of message
+ * @len: length of payload
+ * @dst: destination address
+ *
+ * This function sends @data of length @len to the remote @dst address.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to, using @ept's address as source.
+ * In case there are no TX buffers available, the function will block until
+ * one becomes available, or a timeout of 15 seconds elapses. When the latter
+ * happens, -ERESTARTSYS is returned.
+ *
+ * Can only be called from process context (for now).
+ *
+ * Return: 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
+{
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->sendto)
+		return -ENXIO;
+
+	return ept->ops->sendto(ept, data, len, dst);
+}
+EXPORT_SYMBOL(rpmsg_sendto);
+
+/**
+ * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
+ * @ept: the rpmsg endpoint
+ * @src: source address
+ * @dst: destination address
+ * @data: payload of message
+ * @len: length of payload
+ *
+ * This function sends @data of length @len to the remote @dst address,
+ * and uses @src as the source address.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to.
+ * In case there are no TX buffers available, the function will block until
+ * one becomes available, or a timeout of 15 seconds elapses. When the latter
+ * happens, -ERESTARTSYS is returned.
+ *
+ * Can only be called from process context (for now).
+ *
+ * Return: 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+			  void *data, int len)
+{
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->send_offchannel)
+		return -ENXIO;
+
+	return ept->ops->send_offchannel(ept, src, dst, data, len);
+}
+EXPORT_SYMBOL(rpmsg_send_offchannel);
+
+/**
+ * rpmsg_trysend() - send a message across to the remote processor
+ * @ept: the rpmsg endpoint
+ * @data: payload of message
+ * @len: length of payload
+ *
+ * This function sends @data of length @len on the @ept endpoint.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to, using @ept's address as source and its associated
+ * rpdev's address as destination.
+ * In case there are no TX buffers available, the function will immediately
+ * return -ENOMEM without waiting until one becomes available.
+ *
+ * Can only be called from process context (for now).
+ *
+ * Return: 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->trysend)
+		return -ENXIO;
+
+	return ept->ops->trysend(ept, data, len);
+}
+EXPORT_SYMBOL(rpmsg_trysend);
+
+/**
+ * rpmsg_trysendto() - send a message across to the remote processor, specify dst
+ * @ept: the rpmsg endpoint
+ * @data: payload of message
+ * @len: length of payload
+ * @dst: destination address
+ *
+ * This function sends @data of length @len to the remote @dst address.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to, using @ept's address as source.
+ * In case there are no TX buffers available, the function will immediately
+ * return -ENOMEM without waiting until one becomes available.
+ *
+ * Can only be called from process context (for now).
+ *
+ * Return: 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
+{
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->trysendto)
+		return -ENXIO;
+
+	return ept->ops->trysendto(ept, data, len, dst);
+}
+EXPORT_SYMBOL(rpmsg_trysendto);
+
+/**
+ * rpmsg_poll() - poll the endpoint's send buffers
+ * @ept:	the rpmsg endpoint
+ * @filp:	file for poll_wait()
+ * @wait:	poll_table for poll_wait()
+ *
+ * Return: mask representing the current state of the endpoint's send buffers
+ */
+__poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
+			poll_table *wait)
+{
+	if (WARN_ON(!ept))
+		return 0;
+	if (!ept->ops->poll)
+		return 0;
+
+	return ept->ops->poll(ept, filp, wait);
+}
+EXPORT_SYMBOL(rpmsg_poll);
+
+/**
+ * rpmsg_trysend_offchannel() - send a message using explicit src/dst addresses
+ * @ept: the rpmsg endpoint
+ * @src: source address
+ * @dst: destination address
+ * @data: payload of message
+ * @len: length of payload
+ *
+ * This function sends @data of length @len to the remote @dst address,
+ * and uses @src as the source address.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to.
+ * In case there are no TX buffers available, the function will immediately
+ * return -ENOMEM without waiting until one becomes available.
+ *
+ * Can only be called from process context (for now).
+ *
+ * Return: 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+			     void *data, int len)
+{
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->trysend_offchannel)
+		return -ENXIO;
+
+	return ept->ops->trysend_offchannel(ept, src, dst, data, len);
+}
+EXPORT_SYMBOL(rpmsg_trysend_offchannel);
+
+/**
+ * rpmsg_get_mtu() - get maximum transmission buffer size for sending message.
+ * @ept: the rpmsg endpoint
+ *
+ * This function returns maximum buffer size available for a single outgoing message.
+ *
+ * Return: the maximum transmission size on success and an appropriate error
+ * value on failure.
+ */
+
+ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
+{
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->get_mtu)
+		return -ENOTSUPP;
+
+	return ept->ops->get_mtu(ept);
+}
+EXPORT_SYMBOL(rpmsg_get_mtu);
+
+/*
+ * match a rpmsg channel with a channel info struct.
+ * this is used to make sure we're not creating rpmsg devices for channels
+ * that already exist.
+ */
+static int rpmsg_device_match(struct device *dev, void *data)
+{
+	struct rpmsg_channel_info *chinfo = data;
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+
+	if (chinfo->src != RPMSG_ADDR_ANY && chinfo->src != rpdev->src)
+		return 0;
+
+	if (chinfo->dst != RPMSG_ADDR_ANY && chinfo->dst != rpdev->dst)
+		return 0;
+
+	if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE))
+		return 0;
+
+	/* found a match ! */
+	return 1;
+}
+
+struct device *rpmsg_find_device(struct device *parent,
+				 struct rpmsg_channel_info *chinfo)
+{
+	return device_find_child(parent, chinfo, rpmsg_device_match);
+
+}
+EXPORT_SYMBOL(rpmsg_find_device);
+
+/* sysfs show configuration fields */
+#define rpmsg_show_attr(field, path, format_string)			\
+static ssize_t								\
+field##_show(struct device *dev,					\
+			struct device_attribute *attr, char *buf)	\
+{									\
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);		\
+									\
+	return sprintf(buf, format_string, rpdev->path);		\
+}									\
+static DEVICE_ATTR_RO(field);
+
+#define rpmsg_string_attr(field, member)				\
+static ssize_t								\
+field##_store(struct device *dev, struct device_attribute *attr,	\
+	      const char *buf, size_t sz)				\
+{									\
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);		\
+	const char *old;						\
+	char *new;							\
+									\
+	new = kstrndup(buf, sz, GFP_KERNEL);				\
+	if (!new)							\
+		return -ENOMEM;						\
+	new[strcspn(new, "\n")] = '\0';					\
+									\
+	device_lock(dev);						\
+	old = rpdev->member;						\
+	if (strlen(new)) {						\
+		rpdev->member = new;					\
+	} else {							\
+		kfree(new);						\
+		rpdev->member = NULL;					\
+	}								\
+	device_unlock(dev);						\
+									\
+	kfree(old);							\
+									\
+	return sz;							\
+}									\
+static ssize_t								\
+field##_show(struct device *dev,					\
+	     struct device_attribute *attr, char *buf)			\
+{									\
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);		\
+									\
+	return sprintf(buf, "%s\n", rpdev->member);			\
+}									\
+static DEVICE_ATTR_RW(field)
+
+/* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */
+rpmsg_show_attr(name, id.name, "%s\n");
+rpmsg_show_attr(src, src, "0x%x\n");
+rpmsg_show_attr(dst, dst, "0x%x\n");
+rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n");
+rpmsg_string_attr(driver_override, driver_override);
+
+static ssize_t modalias_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+	ssize_t len;
+
+	len = of_device_modalias(dev, buf, PAGE_SIZE);
+	if (len != -ENODEV)
+		return len;
+
+	return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name);
+}
+static DEVICE_ATTR_RO(modalias);
+
+static struct attribute *rpmsg_dev_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_modalias.attr,
+	&dev_attr_dst.attr,
+	&dev_attr_src.attr,
+	&dev_attr_announce.attr,
+	&dev_attr_driver_override.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(rpmsg_dev);
+
+/* rpmsg devices and drivers are matched using the service name */
+static inline int rpmsg_id_match(const struct rpmsg_device *rpdev,
+				  const struct rpmsg_device_id *id)
+{
+	return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0;
+}
+
+/* match rpmsg channel and rpmsg driver */
+static int rpmsg_dev_match(struct device *dev, struct device_driver *drv)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+	struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
+	const struct rpmsg_device_id *ids = rpdrv->id_table;
+	unsigned int i;
+
+	if (rpdev->driver_override)
+		return !strcmp(rpdev->driver_override, drv->name);
+
+	if (ids)
+		for (i = 0; ids[i].name[0]; i++)
+			if (rpmsg_id_match(rpdev, &ids[i])) {
+				rpdev->id.driver_data = ids[i].driver_data;
+				return 1;
+			}
+
+	return of_driver_match_device(dev, drv);
+}
+
+static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+	int ret;
+
+	ret = of_device_uevent_modalias(dev, env);
+	if (ret != -ENODEV)
+		return ret;
+
+	return add_uevent_var(env, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT,
+					rpdev->id.name);
+}
+
+/*
+ * when an rpmsg driver is probed with a channel, we seamlessly create
+ * it an endpoint, binding its rx callback to a unique local rpmsg
+ * address.
+ *
+ * if we need to, we also announce about this channel to the remote
+ * processor (needed in case the driver is exposing an rpmsg service).
+ */
+static int rpmsg_dev_probe(struct device *dev)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+	struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
+	struct rpmsg_channel_info chinfo = {};
+	struct rpmsg_endpoint *ept = NULL;
+	int err;
+
+	err = dev_pm_domain_attach(dev, true);
+	if (err)
+		goto out;
+
+	if (rpdrv->callback) {
+		strncpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
+		chinfo.src = rpdev->src;
+		chinfo.dst = RPMSG_ADDR_ANY;
+
+		ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, chinfo);
+		if (!ept) {
+			dev_err(dev, "failed to create endpoint\n");
+			err = -ENOMEM;
+			goto out;
+		}
+
+		rpdev->ept = ept;
+		rpdev->src = ept->addr;
+	}
+
+	err = rpdrv->probe(rpdev);
+	if (err) {
+		dev_err(dev, "%s: failed: %d\n", __func__, err);
+		goto destroy_ept;
+	}
+
+	if (ept && rpdev->ops->announce_create) {
+		err = rpdev->ops->announce_create(rpdev);
+		if (err) {
+			dev_err(dev, "failed to announce creation\n");
+			goto remove_rpdev;
+		}
+	}
+
+	return 0;
+
+remove_rpdev:
+	if (rpdrv->remove)
+		rpdrv->remove(rpdev);
+destroy_ept:
+	if (ept)
+		rpmsg_destroy_ept(ept);
+out:
+	return err;
+}
+
+static void rpmsg_dev_remove(struct device *dev)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+	struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
+
+	if (rpdev->ops->announce_destroy)
+		rpdev->ops->announce_destroy(rpdev);
+
+	if (rpdrv->remove)
+		rpdrv->remove(rpdev);
+
+	dev_pm_domain_detach(dev, true);
+
+	if (rpdev->ept)
+		rpmsg_destroy_ept(rpdev->ept);
+}
+
+static struct bus_type rpmsg_bus = {
+	.name		= "rpmsg",
+	.match		= rpmsg_dev_match,
+	.dev_groups	= rpmsg_dev_groups,
+	.uevent		= rpmsg_uevent,
+	.probe		= rpmsg_dev_probe,
+	.remove		= rpmsg_dev_remove,
+};
+
+/*
+ * A helper for registering rpmsg device with driver override and name.
+ * Drivers should not be using it, but instead rpmsg_register_device().
+ */
+int rpmsg_register_device_override(struct rpmsg_device *rpdev,
+				   const char *driver_override)
+{
+	struct device *dev = &rpdev->dev;
+	int ret;
+
+	if (driver_override)
+		strscpy_pad(rpdev->id.name, driver_override, RPMSG_NAME_SIZE);
+
+	dev_set_name(dev, "%s.%s.%d.%d", dev_name(dev->parent),
+		     rpdev->id.name, rpdev->src, rpdev->dst);
+
+	dev->bus = &rpmsg_bus;
+
+	device_initialize(dev);
+	if (driver_override) {
+		ret = driver_set_override(dev, &rpdev->driver_override,
+					  driver_override,
+					  strlen(driver_override));
+		if (ret) {
+			dev_err(dev, "device_set_override failed: %d\n", ret);
+			put_device(dev);
+			return ret;
+		}
+	}
+
+	ret = device_add(dev);
+	if (ret) {
+		dev_err(dev, "device_add failed: %d\n", ret);
+		kfree(rpdev->driver_override);
+		rpdev->driver_override = NULL;
+		put_device(dev);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(rpmsg_register_device_override);
+
+int rpmsg_register_device(struct rpmsg_device *rpdev)
+{
+	return rpmsg_register_device_override(rpdev, NULL);
+}
+EXPORT_SYMBOL(rpmsg_register_device);
+
+/*
+ * find an existing channel using its name + address properties,
+ * and destroy it
+ */
+int rpmsg_unregister_device(struct device *parent,
+			    struct rpmsg_channel_info *chinfo)
+{
+	struct device *dev;
+
+	dev = rpmsg_find_device(parent, chinfo);
+	if (!dev)
+		return -EINVAL;
+
+	device_unregister(dev);
+
+	put_device(dev);
+
+	return 0;
+}
+EXPORT_SYMBOL(rpmsg_unregister_device);
+
+/**
+ * __register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus
+ * @rpdrv: pointer to a struct rpmsg_driver
+ * @owner: owning module/driver
+ *
+ * Return: 0 on success, and an appropriate error value on failure.
+ */
+int __register_rpmsg_driver(struct rpmsg_driver *rpdrv, struct module *owner)
+{
+	rpdrv->drv.bus = &rpmsg_bus;
+	rpdrv->drv.owner = owner;
+	return driver_register(&rpdrv->drv);
+}
+EXPORT_SYMBOL(__register_rpmsg_driver);
+
+/**
+ * unregister_rpmsg_driver() - unregister an rpmsg driver from the rpmsg bus
+ * @rpdrv: pointer to a struct rpmsg_driver
+ *
+ * Return: 0 on success, and an appropriate error value on failure.
+ */
+void unregister_rpmsg_driver(struct rpmsg_driver *rpdrv)
+{
+	driver_unregister(&rpdrv->drv);
+}
+EXPORT_SYMBOL(unregister_rpmsg_driver);
+
+
+static int __init rpmsg_init(void)
+{
+	int ret;
+
+	rpmsg_class = class_create(THIS_MODULE, "rpmsg");
+	if (IS_ERR(rpmsg_class)) {
+		pr_err("failed to create rpmsg class\n");
+		return PTR_ERR(rpmsg_class);
+	}
+
+	ret = bus_register(&rpmsg_bus);
+	if (ret) {
+		pr_err("failed to register rpmsg bus: %d\n", ret);
+		class_destroy(rpmsg_class);
+	}
+	return ret;
+}
+postcore_initcall(rpmsg_init);
+
+static void __exit rpmsg_fini(void)
+{
+	bus_unregister(&rpmsg_bus);
+	class_destroy(rpmsg_class);
+}
+module_exit(rpmsg_fini);
+
+MODULE_DESCRIPTION("remote processor messaging bus");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c
new file mode 100644
index 000000000..107da70fd
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_ctrl.c
@@ -0,0 +1,243 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022, STMicroelectronics
+ * Copyright (c) 2016, Linaro Ltd.
+ * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
+ * Copyright (c) 2012, PetaLogix
+ * Copyright (c) 2011, Texas Instruments, Inc.
+ * Copyright (c) 2011, Google, Inc.
+ *
+ * Based on rpmsg performance statistics driver by Michal Simek, which in turn
+ * was based on TI & Google OMX rpmsg driver.
+ */
+
+#define pr_fmt(fmt)		KBUILD_MODNAME ": " fmt
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/idr.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/rpmsg.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <uapi/linux/rpmsg.h>
+
+#include "rpmsg_char.h"
+#include "rpmsg_internal.h"
+
+#define RPMSG_DEV_MAX	(MINORMASK + 1)
+
+static dev_t rpmsg_major;
+
+static DEFINE_IDA(rpmsg_ctrl_ida);
+static DEFINE_IDA(rpmsg_minor_ida);
+
+#define dev_to_ctrldev(dev) container_of(dev, struct rpmsg_ctrldev, dev)
+#define cdev_to_ctrldev(i_cdev) container_of(i_cdev, struct rpmsg_ctrldev, cdev)
+
+/**
+ * struct rpmsg_ctrldev - control device for instantiating endpoint devices
+ * @rpdev:	underlaying rpmsg device
+ * @cdev:	cdev for the ctrl device
+ * @dev:	device for the ctrl device
+ * @ctrl_lock:	serialize the ioctrls.
+ */
+struct rpmsg_ctrldev {
+	struct rpmsg_device *rpdev;
+	struct cdev cdev;
+	struct device dev;
+	struct mutex ctrl_lock;
+};
+
+static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
+{
+	struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
+
+	get_device(&ctrldev->dev);
+	filp->private_data = ctrldev;
+
+	return 0;
+}
+
+static int rpmsg_ctrldev_release(struct inode *inode, struct file *filp)
+{
+	struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
+
+	put_device(&ctrldev->dev);
+
+	return 0;
+}
+
+static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
+				unsigned long arg)
+{
+	struct rpmsg_ctrldev *ctrldev = fp->private_data;
+	void __user *argp = (void __user *)arg;
+	struct rpmsg_endpoint_info eptinfo;
+	struct rpmsg_channel_info chinfo;
+	struct rpmsg_device *rpdev;
+	int ret = 0;
+
+	if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
+		return -EFAULT;
+
+	memcpy(chinfo.name, eptinfo.name, RPMSG_NAME_SIZE);
+	chinfo.name[RPMSG_NAME_SIZE - 1] = '\0';
+	chinfo.src = eptinfo.src;
+	chinfo.dst = eptinfo.dst;
+
+	mutex_lock(&ctrldev->ctrl_lock);
+	switch (cmd) {
+	case RPMSG_CREATE_EPT_IOCTL:
+		ret = rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo);
+		break;
+
+	case RPMSG_CREATE_DEV_IOCTL:
+		rpdev = rpmsg_create_channel(ctrldev->rpdev, &chinfo);
+		if (!rpdev) {
+			dev_err(&ctrldev->dev, "failed to create %s channel\n", chinfo.name);
+			ret = -ENXIO;
+		}
+		break;
+
+	case RPMSG_RELEASE_DEV_IOCTL:
+		ret = rpmsg_release_channel(ctrldev->rpdev, &chinfo);
+		if (ret)
+			dev_err(&ctrldev->dev, "failed to release %s channel (%d)\n",
+				chinfo.name, ret);
+		break;
+
+	default:
+		ret = -EINVAL;
+	}
+	mutex_unlock(&ctrldev->ctrl_lock);
+
+	return ret;
+};
+
+static const struct file_operations rpmsg_ctrldev_fops = {
+	.owner = THIS_MODULE,
+	.open = rpmsg_ctrldev_open,
+	.release = rpmsg_ctrldev_release,
+	.unlocked_ioctl = rpmsg_ctrldev_ioctl,
+	.compat_ioctl = compat_ptr_ioctl,
+};
+
+static void rpmsg_ctrldev_release_device(struct device *dev)
+{
+	struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
+
+	ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
+	ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
+	kfree(ctrldev);
+}
+
+static int rpmsg_ctrldev_probe(struct rpmsg_device *rpdev)
+{
+	struct rpmsg_ctrldev *ctrldev;
+	struct device *dev;
+	int ret;
+
+	ctrldev = kzalloc(sizeof(*ctrldev), GFP_KERNEL);
+	if (!ctrldev)
+		return -ENOMEM;
+
+	ctrldev->rpdev = rpdev;
+
+	dev = &ctrldev->dev;
+	device_initialize(dev);
+	dev->parent = &rpdev->dev;
+	dev->class = rpmsg_class;
+
+	mutex_init(&ctrldev->ctrl_lock);
+	cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
+	ctrldev->cdev.owner = THIS_MODULE;
+
+	ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
+	if (ret < 0)
+		goto free_ctrldev;
+	dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
+
+	ret = ida_simple_get(&rpmsg_ctrl_ida, 0, 0, GFP_KERNEL);
+	if (ret < 0)
+		goto free_minor_ida;
+	dev->id = ret;
+	dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret);
+
+	ret = cdev_device_add(&ctrldev->cdev, &ctrldev->dev);
+	if (ret)
+		goto free_ctrl_ida;
+
+	/* We can now rely on the release function for cleanup */
+	dev->release = rpmsg_ctrldev_release_device;
+
+	dev_set_drvdata(&rpdev->dev, ctrldev);
+
+	return ret;
+
+free_ctrl_ida:
+	ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
+free_minor_ida:
+	ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
+free_ctrldev:
+	put_device(dev);
+	kfree(ctrldev);
+
+	return ret;
+}
+
+static void rpmsg_ctrldev_remove(struct rpmsg_device *rpdev)
+{
+	struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
+	int ret;
+
+	/* Destroy all endpoints */
+	ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_chrdev_eptdev_destroy);
+	if (ret)
+		dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
+
+	cdev_device_del(&ctrldev->cdev, &ctrldev->dev);
+	put_device(&ctrldev->dev);
+}
+
+static struct rpmsg_driver rpmsg_ctrldev_driver = {
+	.probe = rpmsg_ctrldev_probe,
+	.remove = rpmsg_ctrldev_remove,
+	.drv = {
+		.name = "rpmsg_ctrl",
+	},
+};
+
+static int rpmsg_ctrldev_init(void)
+{
+	int ret;
+
+	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_ctrl");
+	if (ret < 0) {
+		pr_err("failed to allocate char dev region\n");
+		return ret;
+	}
+
+	ret = register_rpmsg_driver(&rpmsg_ctrldev_driver);
+	if (ret < 0) {
+		pr_err("failed to register rpmsg driver\n");
+		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
+	}
+
+	return ret;
+}
+postcore_initcall(rpmsg_ctrldev_init);
+
+static void rpmsg_ctrldev_exit(void)
+{
+	unregister_rpmsg_driver(&rpmsg_ctrldev_driver);
+	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
+}
+module_exit(rpmsg_ctrldev_exit);
+
+MODULE_DESCRIPTION("rpmsg control interface");
+MODULE_ALIAS("rpmsg:" KBUILD_MODNAME);
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
new file mode 100644
index 000000000..39b646d0d
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_internal.h
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * remote processor messaging bus internals
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Ohad Ben-Cohen <ohad@wizery.com>
+ * Brian Swetland <swetland@google.com>
+ */
+
+#ifndef __RPMSG_INTERNAL_H__
+#define __RPMSG_INTERNAL_H__
+
+#include <linux/rpmsg.h>
+#include <linux/poll.h>
+
+#define to_rpmsg_device(d) container_of(d, struct rpmsg_device, dev)
+#define to_rpmsg_driver(d) container_of(d, struct rpmsg_driver, drv)
+
+extern struct class *rpmsg_class;
+
+/**
+ * struct rpmsg_device_ops - indirection table for the rpmsg_device operations
+ * @create_channel:	create backend-specific channel, optional
+ * @release_channel:	release backend-specific channel, optional
+ * @create_ept:		create backend-specific endpoint, required
+ * @announce_create:	announce presence of new channel, optional
+ * @announce_destroy:	announce destruction of channel, optional
+ *
+ * Indirection table for the operations that a rpmsg backend should implement.
+ * @announce_create and @announce_destroy are optional as the backend might
+ * advertise new channels implicitly by creating the endpoints.
+ */
+struct rpmsg_device_ops {
+	struct rpmsg_device *(*create_channel)(struct rpmsg_device *rpdev,
+					       struct rpmsg_channel_info *chinfo);
+	int (*release_channel)(struct rpmsg_device *rpdev,
+			       struct rpmsg_channel_info *chinfo);
+	struct rpmsg_endpoint *(*create_ept)(struct rpmsg_device *rpdev,
+					    rpmsg_rx_cb_t cb, void *priv,
+					    struct rpmsg_channel_info chinfo);
+
+	int (*announce_create)(struct rpmsg_device *rpdev);
+	int (*announce_destroy)(struct rpmsg_device *rpdev);
+};
+
+/**
+ * struct rpmsg_endpoint_ops - indirection table for rpmsg_endpoint operations
+ * @destroy_ept:	see @rpmsg_destroy_ept(), required
+ * @send:		see @rpmsg_send(), required
+ * @sendto:		see @rpmsg_sendto(), optional
+ * @send_offchannel:	see @rpmsg_send_offchannel(), optional
+ * @trysend:		see @rpmsg_trysend(), required
+ * @trysendto:		see @rpmsg_trysendto(), optional
+ * @trysend_offchannel:	see @rpmsg_trysend_offchannel(), optional
+ * @poll:		see @rpmsg_poll(), optional
+ * @get_mtu:		see @rpmsg_get_mtu(), optional
+ *
+ * Indirection table for the operations that a rpmsg backend should implement.
+ * In addition to @destroy_ept, the backend must at least implement @send and
+ * @trysend, while the variants sending data off-channel are optional.
+ */
+struct rpmsg_endpoint_ops {
+	void (*destroy_ept)(struct rpmsg_endpoint *ept);
+
+	int (*send)(struct rpmsg_endpoint *ept, void *data, int len);
+	int (*sendto)(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
+	int (*send_offchannel)(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+				  void *data, int len);
+
+	int (*trysend)(struct rpmsg_endpoint *ept, void *data, int len);
+	int (*trysendto)(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
+	int (*trysend_offchannel)(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+			     void *data, int len);
+	__poll_t (*poll)(struct rpmsg_endpoint *ept, struct file *filp,
+			     poll_table *wait);
+	ssize_t (*get_mtu)(struct rpmsg_endpoint *ept);
+};
+
+struct device *rpmsg_find_device(struct device *parent,
+				 struct rpmsg_channel_info *chinfo);
+
+struct rpmsg_device *rpmsg_create_channel(struct rpmsg_device *rpdev,
+					  struct rpmsg_channel_info *chinfo);
+int rpmsg_release_channel(struct rpmsg_device *rpdev,
+			  struct rpmsg_channel_info *chinfo);
+/**
+ * rpmsg_ctrldev_register_device() - register a char device for control based on rpdev
+ * @rpdev:	prepared rpdev to be used for creating endpoints
+ *
+ * This function wraps rpmsg_register_device() preparing the rpdev for use as
+ * basis for the rpmsg chrdev.
+ */
+static inline int rpmsg_ctrldev_register_device(struct rpmsg_device *rpdev)
+{
+	return rpmsg_register_device_override(rpdev, "rpmsg_ctrl");
+}
+
+#endif
diff --git a/drivers/rpmsg/rpmsg_ns.c b/drivers/rpmsg/rpmsg_ns.c
new file mode 100644
index 000000000..c70ad03ff
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_ns.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) STMicroelectronics 2020 - All Rights Reserved
+ */
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/rpmsg.h>
+#include <linux/rpmsg/ns.h>
+#include <linux/slab.h>
+
+#include "rpmsg_internal.h"
+
+/**
+ * rpmsg_ns_register_device() - register name service device based on rpdev
+ * @rpdev: prepared rpdev to be used for creating endpoints
+ *
+ * This function wraps rpmsg_register_device() preparing the rpdev for use as
+ * basis for the rpmsg name service device.
+ */
+int rpmsg_ns_register_device(struct rpmsg_device *rpdev)
+{
+	rpdev->src = RPMSG_NS_ADDR;
+	rpdev->dst = RPMSG_NS_ADDR;
+
+	return rpmsg_register_device_override(rpdev, "rpmsg_ns");
+}
+EXPORT_SYMBOL(rpmsg_ns_register_device);
+
+/* invoked when a name service announcement arrives */
+static int rpmsg_ns_cb(struct rpmsg_device *rpdev, void *data, int len,
+		       void *priv, u32 src)
+{
+	struct rpmsg_ns_msg *msg = data;
+	struct rpmsg_device *newch;
+	struct rpmsg_channel_info chinfo;
+	struct device *dev = rpdev->dev.parent;
+	int ret;
+
+#if defined(CONFIG_DYNAMIC_DEBUG)
+	dynamic_hex_dump("NS announcement: ", DUMP_PREFIX_NONE, 16, 1,
+			 data, len, true);
+#endif
+
+	if (len != sizeof(*msg)) {
+		dev_err(dev, "malformed ns msg (%d)\n", len);
+		return -EINVAL;
+	}
+
+	/* don't trust the remote processor for null terminating the name */
+	msg->name[RPMSG_NAME_SIZE - 1] = '\0';
+
+	strncpy(chinfo.name, msg->name, sizeof(chinfo.name));
+	chinfo.src = RPMSG_ADDR_ANY;
+	chinfo.dst = rpmsg32_to_cpu(rpdev, msg->addr);
+
+	dev_info(dev, "%sing channel %s addr 0x%x\n",
+		 rpmsg32_to_cpu(rpdev, msg->flags) & RPMSG_NS_DESTROY ?
+		 "destroy" : "creat", msg->name, chinfo.dst);
+
+	if (rpmsg32_to_cpu(rpdev, msg->flags) & RPMSG_NS_DESTROY) {
+		ret = rpmsg_release_channel(rpdev, &chinfo);
+		if (ret)
+			dev_err(dev, "rpmsg_destroy_channel failed: %d\n", ret);
+	} else {
+		newch = rpmsg_create_channel(rpdev, &chinfo);
+		if (!newch)
+			dev_err(dev, "rpmsg_create_channel failed\n");
+	}
+
+	return 0;
+}
+
+static int rpmsg_ns_probe(struct rpmsg_device *rpdev)
+{
+	struct rpmsg_endpoint *ns_ept;
+	struct rpmsg_channel_info ns_chinfo = {
+		.src = RPMSG_NS_ADDR,
+		.dst = RPMSG_NS_ADDR,
+		.name = "name_service",
+	};
+
+	/*
+	 * Create the NS announcement service endpoint associated to the RPMsg
+	 * device. The endpoint will be automatically destroyed when the RPMsg
+	 * device will be deleted.
+	 */
+	ns_ept = rpmsg_create_ept(rpdev, rpmsg_ns_cb, NULL, ns_chinfo);
+	if (!ns_ept) {
+		dev_err(&rpdev->dev, "failed to create the ns ept\n");
+		return -ENOMEM;
+	}
+	rpdev->ept = ns_ept;
+
+	return 0;
+}
+
+static struct rpmsg_driver rpmsg_ns_driver = {
+	.drv.name = KBUILD_MODNAME,
+	.probe = rpmsg_ns_probe,
+};
+
+static int rpmsg_ns_init(void)
+{
+	int ret;
+
+	ret = register_rpmsg_driver(&rpmsg_ns_driver);
+	if (ret < 0)
+		pr_err("%s: Failed to register rpmsg driver\n", __func__);
+
+	return ret;
+}
+postcore_initcall(rpmsg_ns_init);
+
+static void rpmsg_ns_exit(void)
+{
+	unregister_rpmsg_driver(&rpmsg_ns_driver);
+}
+module_exit(rpmsg_ns_exit);
+
+MODULE_DESCRIPTION("Name service announcement rpmsg driver");
+MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@st.com>");
+MODULE_ALIAS("rpmsg:" KBUILD_MODNAME);
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
new file mode 100644
index 000000000..f1af0f674
--- /dev/null
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -0,0 +1,1082 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Virtio-based remote processor messaging bus
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Ohad Ben-Cohen <ohad@wizery.com>
+ * Brian Swetland <swetland@google.com>
+ */
+
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+#include <linux/dma-mapping.h>
+#include <linux/idr.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/rpmsg.h>
+#include <linux/rpmsg/byteorder.h>
+#include <linux/rpmsg/ns.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/virtio.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+#include <linux/wait.h>
+
+#include "rpmsg_internal.h"
+
+/**
+ * struct virtproc_info - virtual remote processor state
+ * @vdev:	the virtio device
+ * @rvq:	rx virtqueue
+ * @svq:	tx virtqueue
+ * @rbufs:	kernel address of rx buffers
+ * @sbufs:	kernel address of tx buffers
+ * @num_bufs:	total number of buffers for rx and tx
+ * @buf_size:   size of one rx or tx buffer
+ * @last_sbuf:	index of last tx buffer used
+ * @bufs_dma:	dma base addr of the buffers
+ * @tx_lock:	protects svq, sbufs and sleepers, to allow concurrent senders.
+ *		sending a message might require waking up a dozing remote
+ *		processor, which involves sleeping, hence the mutex.
+ * @endpoints:	idr of local endpoints, allows fast retrieval
+ * @endpoints_lock: lock of the endpoints set
+ * @sendq:	wait queue of sending contexts waiting for a tx buffers
+ * @sleepers:	number of senders that are waiting for a tx buffer
+ *
+ * This structure stores the rpmsg state of a given virtio remote processor
+ * device (there might be several virtio proc devices for each physical
+ * remote processor).
+ */
+struct virtproc_info {
+	struct virtio_device *vdev;
+	struct virtqueue *rvq, *svq;
+	void *rbufs, *sbufs;
+	unsigned int num_bufs;
+	unsigned int buf_size;
+	int last_sbuf;
+	dma_addr_t bufs_dma;
+	struct mutex tx_lock;
+	struct idr endpoints;
+	struct mutex endpoints_lock;
+	wait_queue_head_t sendq;
+	atomic_t sleepers;
+};
+
+/* The feature bitmap for virtio rpmsg */
+#define VIRTIO_RPMSG_F_NS	0 /* RP supports name service notifications */
+
+/**
+ * struct rpmsg_hdr - common header for all rpmsg messages
+ * @src: source address
+ * @dst: destination address
+ * @reserved: reserved for future use
+ * @len: length of payload (in bytes)
+ * @flags: message flags
+ * @data: @len bytes of message payload data
+ *
+ * Every message sent(/received) on the rpmsg bus begins with this header.
+ */
+struct rpmsg_hdr {
+	__rpmsg32 src;
+	__rpmsg32 dst;
+	__rpmsg32 reserved;
+	__rpmsg16 len;
+	__rpmsg16 flags;
+	u8 data[];
+} __packed;
+
+
+/**
+ * struct virtio_rpmsg_channel - rpmsg channel descriptor
+ * @rpdev: the rpmsg channel device
+ * @vrp: the virtio remote processor device this channel belongs to
+ *
+ * This structure stores the channel that links the rpmsg device to the virtio
+ * remote processor device.
+ */
+struct virtio_rpmsg_channel {
+	struct rpmsg_device rpdev;
+
+	struct virtproc_info *vrp;
+};
+
+#define to_virtio_rpmsg_channel(_rpdev) \
+	container_of(_rpdev, struct virtio_rpmsg_channel, rpdev)
+
+/*
+ * We're allocating buffers of 512 bytes each for communications. The
+ * number of buffers will be computed from the number of buffers supported
+ * by the vring, upto a maximum of 512 buffers (256 in each direction).
+ *
+ * Each buffer will have 16 bytes for the msg header and 496 bytes for
+ * the payload.
+ *
+ * This will utilize a maximum total space of 256KB for the buffers.
+ *
+ * We might also want to add support for user-provided buffers in time.
+ * This will allow bigger buffer size flexibility, and can also be used
+ * to achieve zero-copy messaging.
+ *
+ * Note that these numbers are purely a decision of this driver - we
+ * can change this without changing anything in the firmware of the remote
+ * processor.
+ */
+#define MAX_RPMSG_NUM_BUFS	(512)
+#define MAX_RPMSG_BUF_SIZE	(512)
+
+/*
+ * Local addresses are dynamically allocated on-demand.
+ * We do not dynamically assign addresses from the low 1024 range,
+ * in order to reserve that address range for predefined services.
+ */
+#define RPMSG_RESERVED_ADDRESSES	(1024)
+
+static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept);
+static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
+static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
+			       u32 dst);
+static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
+					u32 dst, void *data, int len);
+static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
+static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
+				  int len, u32 dst);
+static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
+					   u32 dst, void *data, int len);
+static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept);
+static struct rpmsg_device *__rpmsg_create_channel(struct virtproc_info *vrp,
+						   struct rpmsg_channel_info *chinfo);
+
+static const struct rpmsg_endpoint_ops virtio_endpoint_ops = {
+	.destroy_ept = virtio_rpmsg_destroy_ept,
+	.send = virtio_rpmsg_send,
+	.sendto = virtio_rpmsg_sendto,
+	.send_offchannel = virtio_rpmsg_send_offchannel,
+	.trysend = virtio_rpmsg_trysend,
+	.trysendto = virtio_rpmsg_trysendto,
+	.trysend_offchannel = virtio_rpmsg_trysend_offchannel,
+	.get_mtu = virtio_rpmsg_get_mtu,
+};
+
+/**
+ * rpmsg_sg_init - initialize scatterlist according to cpu address location
+ * @sg: scatterlist to fill
+ * @cpu_addr: virtual address of the buffer
+ * @len: buffer length
+ *
+ * An internal function filling scatterlist according to virtual address
+ * location (in vmalloc or in kernel).
+ */
+static void
+rpmsg_sg_init(struct scatterlist *sg, void *cpu_addr, unsigned int len)
+{
+	if (is_vmalloc_addr(cpu_addr)) {
+		sg_init_table(sg, 1);
+		sg_set_page(sg, vmalloc_to_page(cpu_addr), len,
+			    offset_in_page(cpu_addr));
+	} else {
+		WARN_ON(!virt_addr_valid(cpu_addr));
+		sg_init_one(sg, cpu_addr, len);
+	}
+}
+
+/**
+ * __ept_release() - deallocate an rpmsg endpoint
+ * @kref: the ept's reference count
+ *
+ * This function deallocates an ept, and is invoked when its @kref refcount
+ * drops to zero.
+ *
+ * Never invoke this function directly!
+ */
+static void __ept_release(struct kref *kref)
+{
+	struct rpmsg_endpoint *ept = container_of(kref, struct rpmsg_endpoint,
+						  refcount);
+	/*
+	 * At this point no one holds a reference to ept anymore,
+	 * so we can directly free it
+	 */
+	kfree(ept);
+}
+
+/* for more info, see below documentation of rpmsg_create_ept() */
+static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp,
+						 struct rpmsg_device *rpdev,
+						 rpmsg_rx_cb_t cb,
+						 void *priv, u32 addr)
+{
+	int id_min, id_max, id;
+	struct rpmsg_endpoint *ept;
+	struct device *dev = rpdev ? &rpdev->dev : &vrp->vdev->dev;
+
+	ept = kzalloc(sizeof(*ept), GFP_KERNEL);
+	if (!ept)
+		return NULL;
+
+	kref_init(&ept->refcount);
+	mutex_init(&ept->cb_lock);
+
+	ept->rpdev = rpdev;
+	ept->cb = cb;
+	ept->priv = priv;
+	ept->ops = &virtio_endpoint_ops;
+
+	/* do we need to allocate a local address ? */
+	if (addr == RPMSG_ADDR_ANY) {
+		id_min = RPMSG_RESERVED_ADDRESSES;
+		id_max = 0;
+	} else {
+		id_min = addr;
+		id_max = addr + 1;
+	}
+
+	mutex_lock(&vrp->endpoints_lock);
+
+	/* bind the endpoint to an rpmsg address (and allocate one if needed) */
+	id = idr_alloc(&vrp->endpoints, ept, id_min, id_max, GFP_KERNEL);
+	if (id < 0) {
+		dev_err(dev, "idr_alloc failed: %d\n", id);
+		goto free_ept;
+	}
+	ept->addr = id;
+
+	mutex_unlock(&vrp->endpoints_lock);
+
+	return ept;
+
+free_ept:
+	mutex_unlock(&vrp->endpoints_lock);
+	kref_put(&ept->refcount, __ept_release);
+	return NULL;
+}
+
+static struct rpmsg_device *virtio_rpmsg_create_channel(struct rpmsg_device *rpdev,
+							struct rpmsg_channel_info *chinfo)
+{
+	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
+	struct virtproc_info *vrp = vch->vrp;
+
+	return __rpmsg_create_channel(vrp, chinfo);
+}
+
+static int virtio_rpmsg_release_channel(struct rpmsg_device *rpdev,
+					struct rpmsg_channel_info *chinfo)
+{
+	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
+	struct virtproc_info *vrp = vch->vrp;
+
+	return rpmsg_unregister_device(&vrp->vdev->dev, chinfo);
+}
+
+static struct rpmsg_endpoint *virtio_rpmsg_create_ept(struct rpmsg_device *rpdev,
+						      rpmsg_rx_cb_t cb,
+						      void *priv,
+						      struct rpmsg_channel_info chinfo)
+{
+	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
+
+	return __rpmsg_create_ept(vch->vrp, rpdev, cb, priv, chinfo.src);
+}
+
+/**
+ * __rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
+ * @vrp: virtproc which owns this ept
+ * @ept: endpoing to destroy
+ *
+ * An internal function which destroy an ept without assuming it is
+ * bound to an rpmsg channel. This is needed for handling the internal
+ * name service endpoint, which isn't bound to an rpmsg channel.
+ * See also __rpmsg_create_ept().
+ */
+static void
+__rpmsg_destroy_ept(struct virtproc_info *vrp, struct rpmsg_endpoint *ept)
+{
+	/* make sure new inbound messages can't find this ept anymore */
+	mutex_lock(&vrp->endpoints_lock);
+	idr_remove(&vrp->endpoints, ept->addr);
+	mutex_unlock(&vrp->endpoints_lock);
+
+	/* make sure in-flight inbound messages won't invoke cb anymore */
+	mutex_lock(&ept->cb_lock);
+	ept->cb = NULL;
+	mutex_unlock(&ept->cb_lock);
+
+	kref_put(&ept->refcount, __ept_release);
+}
+
+static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
+{
+	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(ept->rpdev);
+
+	__rpmsg_destroy_ept(vch->vrp, ept);
+}
+
+static int virtio_rpmsg_announce_create(struct rpmsg_device *rpdev)
+{
+	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
+	struct virtproc_info *vrp = vch->vrp;
+	struct device *dev = &rpdev->dev;
+	int err = 0;
+
+	/* need to tell remote processor's name service about this channel ? */
+	if (rpdev->announce && rpdev->ept &&
+	    virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
+		struct rpmsg_ns_msg nsm;
+
+		strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
+		nsm.addr = cpu_to_rpmsg32(rpdev, rpdev->ept->addr);
+		nsm.flags = cpu_to_rpmsg32(rpdev, RPMSG_NS_CREATE);
+
+		err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
+		if (err)
+			dev_err(dev, "failed to announce service %d\n", err);
+	}
+
+	return err;
+}
+
+static int virtio_rpmsg_announce_destroy(struct rpmsg_device *rpdev)
+{
+	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
+	struct virtproc_info *vrp = vch->vrp;
+	struct device *dev = &rpdev->dev;
+	int err = 0;
+
+	/* tell remote processor's name service we're removing this channel */
+	if (rpdev->announce && rpdev->ept &&
+	    virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
+		struct rpmsg_ns_msg nsm;
+
+		strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
+		nsm.addr = cpu_to_rpmsg32(rpdev, rpdev->ept->addr);
+		nsm.flags = cpu_to_rpmsg32(rpdev, RPMSG_NS_DESTROY);
+
+		err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
+		if (err)
+			dev_err(dev, "failed to announce service %d\n", err);
+	}
+
+	return err;
+}
+
+static const struct rpmsg_device_ops virtio_rpmsg_ops = {
+	.create_channel = virtio_rpmsg_create_channel,
+	.release_channel = virtio_rpmsg_release_channel,
+	.create_ept = virtio_rpmsg_create_ept,
+	.announce_create = virtio_rpmsg_announce_create,
+	.announce_destroy = virtio_rpmsg_announce_destroy,
+};
+
+static void virtio_rpmsg_release_device(struct device *dev)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
+
+	kfree(rpdev->driver_override);
+	kfree(vch);
+}
+
+/*
+ * create an rpmsg channel using its name and address info.
+ * this function will be used to create both static and dynamic
+ * channels.
+ */
+static struct rpmsg_device *__rpmsg_create_channel(struct virtproc_info *vrp,
+						   struct rpmsg_channel_info *chinfo)
+{
+	struct virtio_rpmsg_channel *vch;
+	struct rpmsg_device *rpdev;
+	struct device *tmp, *dev = &vrp->vdev->dev;
+	int ret;
+
+	/* make sure a similar channel doesn't already exist */
+	tmp = rpmsg_find_device(dev, chinfo);
+	if (tmp) {
+		/* decrement the matched device's refcount back */
+		put_device(tmp);
+		dev_err(dev, "channel %s:%x:%x already exist\n",
+				chinfo->name, chinfo->src, chinfo->dst);
+		return NULL;
+	}
+
+	vch = kzalloc(sizeof(*vch), GFP_KERNEL);
+	if (!vch)
+		return NULL;
+
+	/* Link the channel to our vrp */
+	vch->vrp = vrp;
+
+	/* Assign public information to the rpmsg_device */
+	rpdev = &vch->rpdev;
+	rpdev->src = chinfo->src;
+	rpdev->dst = chinfo->dst;
+	rpdev->ops = &virtio_rpmsg_ops;
+	rpdev->little_endian = virtio_is_little_endian(vrp->vdev);
+
+	/*
+	 * rpmsg server channels has predefined local address (for now),
+	 * and their existence needs to be announced remotely
+	 */
+	rpdev->announce = rpdev->src != RPMSG_ADDR_ANY;
+
+	strncpy(rpdev->id.name, chinfo->name, RPMSG_NAME_SIZE);
+
+	rpdev->dev.parent = &vrp->vdev->dev;
+	rpdev->dev.release = virtio_rpmsg_release_device;
+	ret = rpmsg_register_device(rpdev);
+	if (ret)
+		return NULL;
+
+	return rpdev;
+}
+
+/* super simple buffer "allocator" that is just enough for now */
+static void *get_a_tx_buf(struct virtproc_info *vrp)
+{
+	unsigned int len;
+	void *ret;
+
+	/* support multiple concurrent senders */
+	mutex_lock(&vrp->tx_lock);
+
+	/*
+	 * either pick the next unused tx buffer
+	 * (half of our buffers are used for sending messages)
+	 */
+	if (vrp->last_sbuf < vrp->num_bufs / 2)
+		ret = vrp->sbufs + vrp->buf_size * vrp->last_sbuf++;
+	/* or recycle a used one */
+	else
+		ret = virtqueue_get_buf(vrp->svq, &len);
+
+	mutex_unlock(&vrp->tx_lock);
+
+	return ret;
+}
+
+/**
+ * rpmsg_upref_sleepers() - enable "tx-complete" interrupts, if needed
+ * @vrp: virtual remote processor state
+ *
+ * This function is called before a sender is blocked, waiting for
+ * a tx buffer to become available.
+ *
+ * If we already have blocking senders, this function merely increases
+ * the "sleepers" reference count, and exits.
+ *
+ * Otherwise, if this is the first sender to block, we also enable
+ * virtio's tx callbacks, so we'd be immediately notified when a tx
+ * buffer is consumed (we rely on virtio's tx callback in order
+ * to wake up sleeping senders as soon as a tx buffer is used by the
+ * remote processor).
+ */
+static void rpmsg_upref_sleepers(struct virtproc_info *vrp)
+{
+	/* support multiple concurrent senders */
+	mutex_lock(&vrp->tx_lock);
+
+	/* are we the first sleeping context waiting for tx buffers ? */
+	if (atomic_inc_return(&vrp->sleepers) == 1)
+		/* enable "tx-complete" interrupts before dozing off */
+		virtqueue_enable_cb(vrp->svq);
+
+	mutex_unlock(&vrp->tx_lock);
+}
+
+/**
+ * rpmsg_downref_sleepers() - disable "tx-complete" interrupts, if needed
+ * @vrp: virtual remote processor state
+ *
+ * This function is called after a sender, that waited for a tx buffer
+ * to become available, is unblocked.
+ *
+ * If we still have blocking senders, this function merely decreases
+ * the "sleepers" reference count, and exits.
+ *
+ * Otherwise, if there are no more blocking senders, we also disable
+ * virtio's tx callbacks, to avoid the overhead incurred with handling
+ * those (now redundant) interrupts.
+ */
+static void rpmsg_downref_sleepers(struct virtproc_info *vrp)
+{
+	/* support multiple concurrent senders */
+	mutex_lock(&vrp->tx_lock);
+
+	/* are we the last sleeping context waiting for tx buffers ? */
+	if (atomic_dec_and_test(&vrp->sleepers))
+		/* disable "tx-complete" interrupts */
+		virtqueue_disable_cb(vrp->svq);
+
+	mutex_unlock(&vrp->tx_lock);
+}
+
+/**
+ * rpmsg_send_offchannel_raw() - send a message across to the remote processor
+ * @rpdev: the rpmsg channel
+ * @src: source address
+ * @dst: destination address
+ * @data: payload of message
+ * @len: length of payload
+ * @wait: indicates whether caller should block in case no TX buffers available
+ *
+ * This function is the base implementation for all of the rpmsg sending API.
+ *
+ * It will send @data of length @len to @dst, and say it's from @src. The
+ * message will be sent to the remote processor which the @rpdev channel
+ * belongs to.
+ *
+ * The message is sent using one of the TX buffers that are available for
+ * communication with this remote processor.
+ *
+ * If @wait is true, the caller will be blocked until either a TX buffer is
+ * available, or 15 seconds elapses (we don't want callers to
+ * sleep indefinitely due to misbehaving remote processors), and in that
+ * case -ERESTARTSYS is returned. The number '15' itself was picked
+ * arbitrarily; there's little point in asking drivers to provide a timeout
+ * value themselves.
+ *
+ * Otherwise, if @wait is false, and there are no TX buffers available,
+ * the function will immediately fail, and -ENOMEM will be returned.
+ *
+ * Normally drivers shouldn't use this function directly; instead, drivers
+ * should use the appropriate rpmsg_{try}send{to, _offchannel} API
+ * (see include/linux/rpmsg.h).
+ *
+ * Return: 0 on success and an appropriate error value on failure.
+ */
+static int rpmsg_send_offchannel_raw(struct rpmsg_device *rpdev,
+				     u32 src, u32 dst,
+				     void *data, int len, bool wait)
+{
+	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
+	struct virtproc_info *vrp = vch->vrp;
+	struct device *dev = &rpdev->dev;
+	struct scatterlist sg;
+	struct rpmsg_hdr *msg;
+	int err;
+
+	/* bcasting isn't allowed */
+	if (src == RPMSG_ADDR_ANY || dst == RPMSG_ADDR_ANY) {
+		dev_err(dev, "invalid addr (src 0x%x, dst 0x%x)\n", src, dst);
+		return -EINVAL;
+	}
+
+	/*
+	 * We currently use fixed-sized buffers, and therefore the payload
+	 * length is limited.
+	 *
+	 * One of the possible improvements here is either to support
+	 * user-provided buffers (and then we can also support zero-copy
+	 * messaging), or to improve the buffer allocator, to support
+	 * variable-length buffer sizes.
+	 */
+	if (len > vrp->buf_size - sizeof(struct rpmsg_hdr)) {
+		dev_err(dev, "message is too big (%d)\n", len);
+		return -EMSGSIZE;
+	}
+
+	/* grab a buffer */
+	msg = get_a_tx_buf(vrp);
+	if (!msg && !wait)
+		return -ENOMEM;
+
+	/* no free buffer ? wait for one (but bail after 15 seconds) */
+	while (!msg) {
+		/* enable "tx-complete" interrupts, if not already enabled */
+		rpmsg_upref_sleepers(vrp);
+
+		/*
+		 * sleep until a free buffer is available or 15 secs elapse.
+		 * the timeout period is not configurable because there's
+		 * little point in asking drivers to specify that.
+		 * if later this happens to be required, it'd be easy to add.
+		 */
+		err = wait_event_interruptible_timeout(vrp->sendq,
+					(msg = get_a_tx_buf(vrp)),
+					msecs_to_jiffies(15000));
+
+		/* disable "tx-complete" interrupts if we're the last sleeper */
+		rpmsg_downref_sleepers(vrp);
+
+		/* timeout ? */
+		if (!err) {
+			dev_err(dev, "timeout waiting for a tx buffer\n");
+			return -ERESTARTSYS;
+		}
+	}
+
+	msg->len = cpu_to_rpmsg16(rpdev, len);
+	msg->flags = 0;
+	msg->src = cpu_to_rpmsg32(rpdev, src);
+	msg->dst = cpu_to_rpmsg32(rpdev, dst);
+	msg->reserved = 0;
+	memcpy(msg->data, data, len);
+
+	dev_dbg(dev, "TX From 0x%x, To 0x%x, Len %d, Flags %d, Reserved %d\n",
+		src, dst, len, msg->flags, msg->reserved);
+#if defined(CONFIG_DYNAMIC_DEBUG)
+	dynamic_hex_dump("rpmsg_virtio TX: ", DUMP_PREFIX_NONE, 16, 1,
+			 msg, sizeof(*msg) + len, true);
+#endif
+
+	rpmsg_sg_init(&sg, msg, sizeof(*msg) + len);
+
+	mutex_lock(&vrp->tx_lock);
+
+	/* add message to the remote processor's virtqueue */
+	err = virtqueue_add_outbuf(vrp->svq, &sg, 1, msg, GFP_KERNEL);
+	if (err) {
+		/*
+		 * need to reclaim the buffer here, otherwise it's lost
+		 * (memory won't leak, but rpmsg won't use it again for TX).
+		 * this will wait for a buffer management overhaul.
+		 */
+		dev_err(dev, "virtqueue_add_outbuf failed: %d\n", err);
+		goto out;
+	}
+
+	/* tell the remote processor it has a pending message to read */
+	virtqueue_kick(vrp->svq);
+out:
+	mutex_unlock(&vrp->tx_lock);
+	return err;
+}
+
+static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+	u32 src = ept->addr, dst = rpdev->dst;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
+}
+
+static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
+			       u32 dst)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+	u32 src = ept->addr;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
+}
+
+static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
+					u32 dst, void *data, int len)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
+}
+
+static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+	u32 src = ept->addr, dst = rpdev->dst;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
+}
+
+static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
+				  int len, u32 dst)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+	u32 src = ept->addr;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
+}
+
+static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
+					   u32 dst, void *data, int len)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
+}
+
+static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
+
+	return vch->vrp->buf_size - sizeof(struct rpmsg_hdr);
+}
+
+static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
+			     struct rpmsg_hdr *msg, unsigned int len)
+{
+	struct rpmsg_endpoint *ept;
+	struct scatterlist sg;
+	bool little_endian = virtio_is_little_endian(vrp->vdev);
+	unsigned int msg_len = __rpmsg16_to_cpu(little_endian, msg->len);
+	int err;
+
+	dev_dbg(dev, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n",
+		__rpmsg32_to_cpu(little_endian, msg->src),
+		__rpmsg32_to_cpu(little_endian, msg->dst), msg_len,
+		__rpmsg16_to_cpu(little_endian, msg->flags),
+		__rpmsg32_to_cpu(little_endian, msg->reserved));
+#if defined(CONFIG_DYNAMIC_DEBUG)
+	dynamic_hex_dump("rpmsg_virtio RX: ", DUMP_PREFIX_NONE, 16, 1,
+			 msg, sizeof(*msg) + msg_len, true);
+#endif
+
+	/*
+	 * We currently use fixed-sized buffers, so trivially sanitize
+	 * the reported payload length.
+	 */
+	if (len > vrp->buf_size ||
+	    msg_len > (len - sizeof(struct rpmsg_hdr))) {
+		dev_warn(dev, "inbound msg too big: (%d, %d)\n", len, msg_len);
+		return -EINVAL;
+	}
+
+	/* use the dst addr to fetch the callback of the appropriate user */
+	mutex_lock(&vrp->endpoints_lock);
+
+	ept = idr_find(&vrp->endpoints, __rpmsg32_to_cpu(little_endian, msg->dst));
+
+	/* let's make sure no one deallocates ept while we use it */
+	if (ept)
+		kref_get(&ept->refcount);
+
+	mutex_unlock(&vrp->endpoints_lock);
+
+	if (ept) {
+		/* make sure ept->cb doesn't go away while we use it */
+		mutex_lock(&ept->cb_lock);
+
+		if (ept->cb)
+			ept->cb(ept->rpdev, msg->data, msg_len, ept->priv,
+				__rpmsg32_to_cpu(little_endian, msg->src));
+
+		mutex_unlock(&ept->cb_lock);
+
+		/* farewell, ept, we don't need you anymore */
+		kref_put(&ept->refcount, __ept_release);
+	} else
+		dev_warn_ratelimited(dev, "msg received with no recipient\n");
+
+	/* publish the real size of the buffer */
+	rpmsg_sg_init(&sg, msg, vrp->buf_size);
+
+	/* add the buffer back to the remote processor's virtqueue */
+	err = virtqueue_add_inbuf(vrp->rvq, &sg, 1, msg, GFP_KERNEL);
+	if (err < 0) {
+		dev_err(dev, "failed to add a virtqueue buffer: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+/* called when an rx buffer is used, and it's time to digest a message */
+static void rpmsg_recv_done(struct virtqueue *rvq)
+{
+	struct virtproc_info *vrp = rvq->vdev->priv;
+	struct device *dev = &rvq->vdev->dev;
+	struct rpmsg_hdr *msg;
+	unsigned int len, msgs_received = 0;
+	int err;
+
+	msg = virtqueue_get_buf(rvq, &len);
+	if (!msg) {
+		dev_err(dev, "uhm, incoming signal, but no used buffer ?\n");
+		return;
+	}
+
+	while (msg) {
+		err = rpmsg_recv_single(vrp, dev, msg, len);
+		if (err)
+			break;
+
+		msgs_received++;
+
+		msg = virtqueue_get_buf(rvq, &len);
+	}
+
+	dev_dbg(dev, "Received %u messages\n", msgs_received);
+
+	/* tell the remote processor we added another available rx buffer */
+	if (msgs_received)
+		virtqueue_kick(vrp->rvq);
+}
+
+/*
+ * This is invoked whenever the remote processor completed processing
+ * a TX msg we just sent it, and the buffer is put back to the used ring.
+ *
+ * Normally, though, we suppress this "tx complete" interrupt in order to
+ * avoid the incurred overhead.
+ */
+static void rpmsg_xmit_done(struct virtqueue *svq)
+{
+	struct virtproc_info *vrp = svq->vdev->priv;
+
+	dev_dbg(&svq->vdev->dev, "%s\n", __func__);
+
+	/* wake up potential senders that are waiting for a tx buffer */
+	wake_up_interruptible(&vrp->sendq);
+}
+
+/*
+ * Called to expose to user a /dev/rpmsg_ctrlX interface allowing to
+ * create endpoint-to-endpoint communication without associated RPMsg channel.
+ * The endpoints are rattached to the ctrldev RPMsg device.
+ */
+static struct rpmsg_device *rpmsg_virtio_add_ctrl_dev(struct virtio_device *vdev)
+{
+	struct virtproc_info *vrp = vdev->priv;
+	struct virtio_rpmsg_channel *vch;
+	struct rpmsg_device *rpdev_ctrl;
+	int err = 0;
+
+	vch = kzalloc(sizeof(*vch), GFP_KERNEL);
+	if (!vch)
+		return ERR_PTR(-ENOMEM);
+
+	/* Link the channel to the vrp */
+	vch->vrp = vrp;
+
+	/* Assign public information to the rpmsg_device */
+	rpdev_ctrl = &vch->rpdev;
+	rpdev_ctrl->ops = &virtio_rpmsg_ops;
+
+	rpdev_ctrl->dev.parent = &vrp->vdev->dev;
+	rpdev_ctrl->dev.release = virtio_rpmsg_release_device;
+	rpdev_ctrl->little_endian = virtio_is_little_endian(vrp->vdev);
+
+	err = rpmsg_ctrldev_register_device(rpdev_ctrl);
+	if (err) {
+		/* vch will be free in virtio_rpmsg_release_device() */
+		return ERR_PTR(err);
+	}
+
+	return rpdev_ctrl;
+}
+
+static void rpmsg_virtio_del_ctrl_dev(struct rpmsg_device *rpdev_ctrl)
+{
+	if (!rpdev_ctrl)
+		return;
+	device_unregister(&rpdev_ctrl->dev);
+}
+
+static int rpmsg_probe(struct virtio_device *vdev)
+{
+	vq_callback_t *vq_cbs[] = { rpmsg_recv_done, rpmsg_xmit_done };
+	static const char * const names[] = { "input", "output" };
+	struct virtqueue *vqs[2];
+	struct virtproc_info *vrp;
+	struct virtio_rpmsg_channel *vch = NULL;
+	struct rpmsg_device *rpdev_ns, *rpdev_ctrl;
+	void *bufs_va;
+	int err = 0, i;
+	size_t total_buf_space;
+	bool notify;
+
+	vrp = kzalloc(sizeof(*vrp), GFP_KERNEL);
+	if (!vrp)
+		return -ENOMEM;
+
+	vrp->vdev = vdev;
+
+	idr_init(&vrp->endpoints);
+	mutex_init(&vrp->endpoints_lock);
+	mutex_init(&vrp->tx_lock);
+	init_waitqueue_head(&vrp->sendq);
+
+	/* We expect two virtqueues, rx and tx (and in this order) */
+	err = virtio_find_vqs(vdev, 2, vqs, vq_cbs, names, NULL);
+	if (err)
+		goto free_vrp;
+
+	vrp->rvq = vqs[0];
+	vrp->svq = vqs[1];
+
+	/* we expect symmetric tx/rx vrings */
+	WARN_ON(virtqueue_get_vring_size(vrp->rvq) !=
+		virtqueue_get_vring_size(vrp->svq));
+
+	/* we need less buffers if vrings are small */
+	if (virtqueue_get_vring_size(vrp->rvq) < MAX_RPMSG_NUM_BUFS / 2)
+		vrp->num_bufs = virtqueue_get_vring_size(vrp->rvq) * 2;
+	else
+		vrp->num_bufs = MAX_RPMSG_NUM_BUFS;
+
+	vrp->buf_size = MAX_RPMSG_BUF_SIZE;
+
+	total_buf_space = vrp->num_bufs * vrp->buf_size;
+
+	/* allocate coherent memory for the buffers */
+	bufs_va = dma_alloc_coherent(vdev->dev.parent,
+				     total_buf_space, &vrp->bufs_dma,
+				     GFP_KERNEL);
+	if (!bufs_va) {
+		err = -ENOMEM;
+		goto vqs_del;
+	}
+
+	dev_dbg(&vdev->dev, "buffers: va %pK, dma %pad\n",
+		bufs_va, &vrp->bufs_dma);
+
+	/* half of the buffers is dedicated for RX */
+	vrp->rbufs = bufs_va;
+
+	/* and half is dedicated for TX */
+	vrp->sbufs = bufs_va + total_buf_space / 2;
+
+	/* set up the receive buffers */
+	for (i = 0; i < vrp->num_bufs / 2; i++) {
+		struct scatterlist sg;
+		void *cpu_addr = vrp->rbufs + i * vrp->buf_size;
+
+		rpmsg_sg_init(&sg, cpu_addr, vrp->buf_size);
+
+		err = virtqueue_add_inbuf(vrp->rvq, &sg, 1, cpu_addr,
+					  GFP_KERNEL);
+		WARN_ON(err); /* sanity check; this can't really happen */
+	}
+
+	/* suppress "tx-complete" interrupts */
+	virtqueue_disable_cb(vrp->svq);
+
+	vdev->priv = vrp;
+
+	rpdev_ctrl = rpmsg_virtio_add_ctrl_dev(vdev);
+	if (IS_ERR(rpdev_ctrl)) {
+		err = PTR_ERR(rpdev_ctrl);
+		goto free_coherent;
+	}
+
+	/* if supported by the remote processor, enable the name service */
+	if (virtio_has_feature(vdev, VIRTIO_RPMSG_F_NS)) {
+		vch = kzalloc(sizeof(*vch), GFP_KERNEL);
+		if (!vch) {
+			err = -ENOMEM;
+			goto free_ctrldev;
+		}
+
+		/* Link the channel to our vrp */
+		vch->vrp = vrp;
+
+		/* Assign public information to the rpmsg_device */
+		rpdev_ns = &vch->rpdev;
+		rpdev_ns->ops = &virtio_rpmsg_ops;
+		rpdev_ns->little_endian = virtio_is_little_endian(vrp->vdev);
+
+		rpdev_ns->dev.parent = &vrp->vdev->dev;
+		rpdev_ns->dev.release = virtio_rpmsg_release_device;
+
+		err = rpmsg_ns_register_device(rpdev_ns);
+		if (err)
+			/* vch will be free in virtio_rpmsg_release_device() */
+			goto free_ctrldev;
+	}
+
+	/*
+	 * Prepare to kick but don't notify yet - we can't do this before
+	 * device is ready.
+	 */
+	notify = virtqueue_kick_prepare(vrp->rvq);
+
+	/* From this point on, we can notify and get callbacks. */
+	virtio_device_ready(vdev);
+
+	/* tell the remote processor it can start sending messages */
+	/*
+	 * this might be concurrent with callbacks, but we are only
+	 * doing notify, not a full kick here, so that's ok.
+	 */
+	if (notify)
+		virtqueue_notify(vrp->rvq);
+
+	dev_info(&vdev->dev, "rpmsg host is online\n");
+
+	return 0;
+
+free_ctrldev:
+	rpmsg_virtio_del_ctrl_dev(rpdev_ctrl);
+free_coherent:
+	dma_free_coherent(vdev->dev.parent, total_buf_space,
+			  bufs_va, vrp->bufs_dma);
+vqs_del:
+	vdev->config->del_vqs(vrp->vdev);
+free_vrp:
+	kfree(vrp);
+	return err;
+}
+
+static int rpmsg_remove_device(struct device *dev, void *data)
+{
+	device_unregister(dev);
+
+	return 0;
+}
+
+static void rpmsg_remove(struct virtio_device *vdev)
+{
+	struct virtproc_info *vrp = vdev->priv;
+	size_t total_buf_space = vrp->num_bufs * vrp->buf_size;
+	int ret;
+
+	virtio_reset_device(vdev);
+
+	ret = device_for_each_child(&vdev->dev, NULL, rpmsg_remove_device);
+	if (ret)
+		dev_warn(&vdev->dev, "can't remove rpmsg device: %d\n", ret);
+
+	idr_destroy(&vrp->endpoints);
+
+	vdev->config->del_vqs(vrp->vdev);
+
+	dma_free_coherent(vdev->dev.parent, total_buf_space,
+			  vrp->rbufs, vrp->bufs_dma);
+
+	kfree(vrp);
+}
+
+static struct virtio_device_id id_table[] = {
+	{ VIRTIO_ID_RPMSG, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+
+static unsigned int features[] = {
+	VIRTIO_RPMSG_F_NS,
+};
+
+static struct virtio_driver virtio_ipc_driver = {
+	.feature_table	= features,
+	.feature_table_size = ARRAY_SIZE(features),
+	.driver.name	= KBUILD_MODNAME,
+	.driver.owner	= THIS_MODULE,
+	.id_table	= id_table,
+	.probe		= rpmsg_probe,
+	.remove		= rpmsg_remove,
+};
+
+static int __init rpmsg_init(void)
+{
+	int ret;
+
+	ret = register_virtio_driver(&virtio_ipc_driver);
+	if (ret)
+		pr_err("failed to register virtio driver: %d\n", ret);
+
+	return ret;
+}
+subsys_initcall(rpmsg_init);
+
+static void __exit rpmsg_fini(void)
+{
+	unregister_virtio_driver(&virtio_ipc_driver);
+}
+module_exit(rpmsg_fini);
+
+MODULE_DEVICE_TABLE(virtio, id_table);
+MODULE_DESCRIPTION("Virtio-based remote processor messaging bus");
+MODULE_LICENSE("GPL v2");