sched_ext: Maintain an online cid mask in the scheduler arenagrafted

Schedulers on the default cid mapping treat [0, nr_online_cids) as the
online set and restart on hotplug. Schedulers that install their own mapping
with scx_bpf_cid_override() have no way to learn which cids are online: the
count no longer identifies members and the CPU-form cpumask is unusable from
cid programs. This is an obvious hole in the cid API.

Add scx_bpf_online_cmask(), a kernel-maintained cmask in the scheduler's
arena, allocated alongside the per-CPU scratch masks and populated after the
cid mapping is finalized and before ops.init(), for child schedulers too.
The pointer stays valid through ops.exit() with no reference to take. It is
the arena offset as a void pointer, the same form struct_ops arena arguments
arrive in. The verifier types the void return as a scalar for the program's
arena cast.

The mask follows the SCX hotplug notifications: seeded from cpu_active_mask
and updated before ops.cid_online/offline() runs, so it lags cpu_online_mask
only inside a hotplug transition. Updates walk the scheduler list under the
lock that also serializes unlinking. Reads are live, not atomic snapshots.
Root initialization excludes hotplug.

v2: Reworded the getter kerneldoc (Andrea Righi).

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

17 files changed, 8272 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..1e02b58ff
--- /dev/null
+++ b/drivers/rpmsg/Makefile
@@ -0,0 +1,13 @@
+# 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-$(CONFIG_RPMSG_MTK_SCP)	+= mtk_rpmsg.o
+CFLAGS_qcom_glink_native.o	:= -I$(src)
+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..1b670ed54
--- /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_obj(*mept);
+	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, const 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, const 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_obj(*mdev);
+	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_obj(*info);
+	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_obj(*mtk_subdev);
+	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..d9d4468e4
--- /dev/null
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -0,0 +1,1989 @@
+// 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/sizes.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/workqueue.h>
+#include <linux/mailbox_client.h>
+
+#include "rpmsg_internal.h"
+#include "qcom_glink_native.h"
+
+#define CREATE_TRACE_POINTS
+#include "qcom_glink_trace.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 {
+	/* New members MUST be added within the __struct_group() macro below. */
+	__struct_group(glink_msg_hdr, hdr, __packed,
+		__le16 cmd;
+		__le16 param1;
+		__le32 param2;
+	);
+	u8 data[];
+} __packed;
+static_assert(offsetof(struct glink_msg, data) == sizeof(struct glink_msg_hdr),
+	      "struct member likely outside of __struct_group()");
+
+/**
+ * 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_hdr 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
+ * @label:	identifier of the glink edge
+ * @rx_pipe:	pipe object for receive FIFO
+ * @tx_pipe:	pipe object for transmit FIFO
+ * @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
+ * @abort_tx:	flag indicating that all tx attempts should fail
+ */
+struct qcom_glink {
+	struct device *dev;
+
+	const char *label;
+
+	struct qcom_glink_pipe *rx_pipe;
+	struct qcom_glink_pipe *tx_pipe;
+
+	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;
+
+	bool abort_tx;
+};
+
+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_received: flag indicating that an intent has been received
+ * @intent_req_wq: wait queue 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;
+	int intent_req_result;
+	bool intent_received;
+	wait_queue_head_t intent_req_wq;
+};
+
+#define to_glink_channel(_ept) container_of(_ept, struct glink_channel, ept)
+
+static const struct rpmsg_endpoint_ops glink_endpoint_ops;
+
+#define GLINK_CMD_VERSION		0
+#define GLINK_CMD_VERSION_ACK		1
+#define GLINK_CMD_OPEN			2
+#define GLINK_CMD_CLOSE			3
+#define GLINK_CMD_OPEN_ACK		4
+#define GLINK_CMD_INTENT		5
+#define GLINK_CMD_RX_DONE		6
+#define GLINK_CMD_RX_INTENT_REQ		7
+#define GLINK_CMD_RX_INTENT_REQ_ACK	8
+#define GLINK_CMD_TX_DATA		9
+#define GLINK_CMD_CLOSE_ACK		11
+#define GLINK_CMD_TX_DATA_CONT		12
+#define GLINK_CMD_READ_NOTIF		13
+#define GLINK_CMD_RX_DONE_W_REUSE	14
+#define GLINK_CMD_SIGNALS		15
+
+#define GLINK_FEATURE_INTENTLESS	BIT(1)
+
+#define NATIVE_DTR_SIG			NATIVE_DSR_SIG
+#define NATIVE_DSR_SIG			BIT(31)
+#define NATIVE_RTS_SIG			NATIVE_CTS_SIG
+#define NATIVE_CTS_SIG			BIT(30)
+
+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_obj(*channel);
+	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_waitqueue_head(&channel->intent_req_wq);
+
+	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_peek(struct qcom_glink *glink,
+			       void *data, unsigned int offset, size_t count)
+{
+	glink->rx_pipe->peek(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_tx_kick(struct qcom_glink *glink)
+{
+	glink->tx_pipe->kick(glink->tx_pipe);
+}
+
+static void qcom_glink_send_read_notify(struct qcom_glink *glink)
+{
+	struct glink_msg msg;
+
+	msg.cmd = cpu_to_le16(GLINK_CMD_READ_NOTIF);
+	msg.param1 = 0;
+	msg.param2 = 0;
+
+	qcom_glink_tx_write(glink, &msg, sizeof(msg), NULL, 0);
+
+	qcom_glink_tx_kick(glink);
+}
+
+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);
+
+	if (glink->abort_tx) {
+		ret = -EIO;
+		goto out;
+	}
+
+	while (qcom_glink_tx_avail(glink) < tlen) {
+		if (!wait) {
+			ret = -EAGAIN;
+			goto out;
+		}
+
+		if (glink->abort_tx) {
+			ret = -EIO;
+			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);
+	qcom_glink_tx_kick(glink);
+
+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(GLINK_CMD_VERSION);
+	msg.param1 = cpu_to_le16(GLINK_VERSION_1);
+	msg.param2 = cpu_to_le32(glink->features);
+
+	trace_qcom_glink_cmd_version_tx(glink->label, GLINK_VERSION_1, 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(GLINK_CMD_VERSION_ACK);
+	msg.param1 = cpu_to_le16(GLINK_VERSION_1);
+	msg.param2 = cpu_to_le32(glink->features);
+
+	trace_qcom_glink_cmd_version_ack_tx(glink->label, msg.param1, msg.param2);
+
+	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(GLINK_CMD_OPEN_ACK);
+	msg.param1 = cpu_to_le16(channel->rcid);
+	msg.param2 = cpu_to_le32(0);
+
+	trace_qcom_glink_cmd_open_ack_tx(glink->label, channel->name,
+					 channel->lcid, channel->rcid);
+
+	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;
+
+	qcom_glink_rx_advance(glink, ALIGN(sizeof(struct glink_msg), 8));
+
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	channel = idr_find(&glink->rcids, cid);
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+
+	trace_qcom_glink_cmd_rx_intent_req_ack_rx(glink->label,
+						  channel ? channel->name : NULL,
+						  channel ? channel->lcid : 0,
+						  cid, granted);
+	if (!channel) {
+		dev_err(glink->dev, "unable to find channel\n");
+		return;
+	}
+
+	WRITE_ONCE(channel->intent_req_result, granted);
+	wake_up_all(&channel->intent_req_wq);
+}
+
+static void qcom_glink_intent_req_abort(struct glink_channel *channel)
+{
+	WRITE_ONCE(channel->intent_req_result, 0);
+	wake_up_all(&channel->intent_req_wq);
+}
+
+/**
+ * qcom_glink_send_open_req() - send a GLINK_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 GLINK_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)
+{
+	DEFINE_RAW_FLEX(struct glink_msg, req, data, GLINK_NAME_SIZE);
+	int name_len = strlen(channel->name) + 1;
+	int req_len = ALIGN(sizeof(*req) + 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->cmd = cpu_to_le16(GLINK_CMD_OPEN);
+	req->param1 = cpu_to_le16(channel->lcid);
+	req->param2 = cpu_to_le32(name_len);
+	strcpy(req->data, channel->name);
+
+	trace_qcom_glink_cmd_open_tx(glink->label, channel->name,
+				     channel->lcid, channel->rcid);
+
+	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(GLINK_CMD_CLOSE);
+	req.param1 = cpu_to_le16(channel->lcid);
+	req.param2 = 0;
+
+	trace_qcom_glink_cmd_close_tx(glink->label, channel->name,
+				      channel->lcid, channel->rcid);
+
+	qcom_glink_tx(glink, &req, sizeof(req), NULL, 0, true);
+}
+
+static void qcom_glink_send_close_ack(struct qcom_glink *glink,
+				      struct glink_channel *channel)
+{
+	struct glink_msg req;
+
+	req.cmd = cpu_to_le16(GLINK_CMD_CLOSE_ACK);
+	req.param1 = cpu_to_le16(channel->rcid);
+	req.param2 = 0;
+
+	trace_qcom_glink_cmd_close_ack_tx(glink->label, channel->name,
+					  channel->lcid, channel->rcid);
+
+	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 ? GLINK_CMD_RX_DONE_W_REUSE : GLINK_CMD_RX_DONE;
+		cmd.lcid = cid;
+		cmd.liid = iid;
+
+		trace_qcom_glink_cmd_rx_done_tx(glink->label, channel->name,
+						channel->lcid, channel->rcid, cmd.liid, reuse);
+
+		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)
+{
+	trace_qcom_glink_cmd_version_rx(glink->label, version, 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)
+{
+	trace_qcom_glink_cmd_version_ack_rx(glink->label, version, 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;
+
+	trace_qcom_glink_cmd_rx_intent_req_ack_tx(glink->label, channel->name,
+						  channel->lcid, channel->rcid,
+						  granted);
+
+	msg.cmd = cpu_to_le16(GLINK_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(GLINK_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);
+
+	trace_qcom_glink_cmd_intent_tx(glink->label, channel->name,
+				       channel->lcid, channel->rcid,
+				       cmd.count, cmd.size, cmd.liid);
+
+	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_obj(*intent);
+	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;
+
+	qcom_glink_rx_advance(glink, ALIGN(sizeof(struct glink_msg), 8));
+
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	channel = idr_find(&glink->rcids, cid);
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+
+	trace_qcom_glink_cmd_rx_done_rx(glink->label, channel ? channel->name : NULL,
+					channel ? channel->lcid : 0, cid, iid, reuse);
+	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);
+
+	if (reuse) {
+		WRITE_ONCE(channel->intent_received, true);
+		wake_up_all(&channel->intent_req_wq);
+	}
+}
+
+/**
+ * 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);
+
+	trace_qcom_glink_cmd_rx_intent_req_rx(glink->label,
+					      channel ? channel->name : NULL,
+					      channel ? channel->lcid : 0,
+					      cid, size);
+	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_flex(*dcmd, data, extra, GFP_ATOMIC);
+	if (!dcmd)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&dcmd->node);
+
+	qcom_glink_rx_peek(glink,
+			   container_of(&dcmd->msg, struct glink_msg, hdr), 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_hdr 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_peek(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);
+	liid = le32_to_cpu(hdr.msg.param2);
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	channel = idr_find(&glink->rcids, rcid);
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+
+	trace_qcom_glink_cmd_tx_data_rx(glink->label, channel ? channel->name : NULL,
+					channel ? channel->lcid : 0, rcid,
+					liid, chunk_size, left_size,
+					hdr.msg.cmd == GLINK_CMD_TX_DATA_CONT);
+	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_obj(*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 {
+		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_peek(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_rx_read_notif(struct qcom_glink *glink)
+{
+	trace_qcom_glink_cmd_read_notif_rx(glink->label);
+
+	qcom_glink_rx_advance(glink, ALIGN(sizeof(struct glink_msg), 8));
+	qcom_glink_tx_kick(glink);
+}
+
+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_hdr 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) {
+		trace_qcom_glink_cmd_intent_rx(glink->label, NULL, 0, cid, count, 0, 0);
+		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_peek(glink, msg, 0, msglen);
+
+	trace_qcom_glink_cmd_intent_rx(glink->label, channel->name,
+				       channel->lcid, cid, count,
+				       count > 0 ? msg->intents[0].size : 0,
+				       count > 0 ? msg->intents[0].iid : 0);
+
+	for (i = 0; i < count; ++i) {
+		intent = kzalloc_obj(*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");
+	}
+
+	WRITE_ONCE(channel->intent_received, true);
+	wake_up_all(&channel->intent_req_wq);
+
+	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;
+
+	qcom_glink_rx_advance(glink, ALIGN(sizeof(struct glink_msg), 8));
+
+	spin_lock(&glink->idr_lock);
+	channel = idr_find(&glink->lcids, lcid);
+	spin_unlock(&glink->idr_lock);
+
+	trace_qcom_glink_cmd_open_ack_rx(glink->label, channel ? channel->name : NULL,
+					 lcid, channel ? channel->rcid : 0);
+	if (!channel) {
+		dev_err(glink->dev, "Invalid open ack packet\n");
+		return -EINVAL;
+	}
+
+	complete_all(&channel->open_ack);
+
+	return 0;
+}
+
+/**
+ * qcom_glink_set_flow_control() - convert a signal cmd to wire format and transmit
+ * @ept:	Rpmsg endpoint for channel.
+ * @pause:	Pause transmission
+ * @dst:	destination address of the endpoint
+ *
+ * Return: 0 on success or standard Linux error code.
+ */
+static int qcom_glink_set_flow_control(struct rpmsg_endpoint *ept, bool pause, u32 dst)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+	struct qcom_glink *glink = channel->glink;
+	struct glink_msg msg;
+	u32 sigs = 0;
+
+	if (pause)
+		sigs |= NATIVE_DTR_SIG | NATIVE_RTS_SIG;
+
+	msg.cmd = cpu_to_le16(GLINK_CMD_SIGNALS);
+	msg.param1 = cpu_to_le16(channel->lcid);
+	msg.param2 = cpu_to_le32(sigs);
+
+	trace_qcom_glink_cmd_signal_tx(glink->label, channel->name,
+				       channel->lcid, channel->rcid, sigs);
+
+	return qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
+}
+
+static void qcom_glink_handle_signals(struct qcom_glink *glink,
+				      unsigned int rcid, unsigned int sigs)
+{
+	struct glink_channel *channel;
+	unsigned long flags;
+	bool enable;
+
+	qcom_glink_rx_advance(glink, ALIGN(sizeof(struct glink_msg), 8));
+
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	channel = idr_find(&glink->rcids, rcid);
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+
+	trace_qcom_glink_cmd_signal_rx(glink->label, channel ? channel->name : NULL,
+				       channel ? channel->lcid : 0, rcid, sigs);
+	if (!channel) {
+		dev_err(glink->dev, "signal for non-existing channel\n");
+		return;
+	}
+
+	enable = sigs & NATIVE_DSR_SIG || sigs & NATIVE_CTS_SIG;
+
+	if (channel->ept.flow_cb)
+		channel->ept.flow_cb(channel->ept.rpdev, channel->ept.priv, enable);
+}
+
+void qcom_glink_native_rx(struct qcom_glink *glink)
+{
+	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_peek(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 GLINK_CMD_VERSION:
+		case GLINK_CMD_VERSION_ACK:
+		case GLINK_CMD_CLOSE:
+		case GLINK_CMD_CLOSE_ACK:
+		case GLINK_CMD_RX_INTENT_REQ:
+			ret = qcom_glink_rx_defer(glink, 0);
+			break;
+		case GLINK_CMD_OPEN_ACK:
+			ret = qcom_glink_rx_open_ack(glink, param1);
+			break;
+		case GLINK_CMD_OPEN:
+			/* upper 16 bits of param2 are the "prio" field */
+			ret = qcom_glink_rx_defer(glink, param2 & 0xffff);
+			break;
+		case GLINK_CMD_TX_DATA:
+		case GLINK_CMD_TX_DATA_CONT:
+			ret = qcom_glink_rx_data(glink, avail);
+			break;
+		case GLINK_CMD_READ_NOTIF:
+			qcom_glink_rx_read_notif(glink);
+			break;
+		case GLINK_CMD_INTENT:
+			qcom_glink_handle_intent(glink, param1, param2, avail);
+			break;
+		case GLINK_CMD_RX_DONE:
+			qcom_glink_handle_rx_done(glink, param1, param2, false);
+			break;
+		case GLINK_CMD_RX_DONE_W_REUSE:
+			qcom_glink_handle_rx_done(glink, param1, param2, true);
+			break;
+		case GLINK_CMD_RX_INTENT_REQ_ACK:
+			qcom_glink_handle_intent_req_ack(glink, param1, param2);
+			break;
+		case GLINK_CMD_SIGNALS:
+			qcom_glink_handle_signals(glink, param1, param2);
+			break;
+		default:
+			dev_err(glink->dev, "unhandled rx cmd: %d\n", cmd);
+			ret = -EINVAL;
+			break;
+		}
+
+		if (ret)
+			break;
+	}
+}
+EXPORT_SYMBOL(qcom_glink_native_rx);
+
+/* 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_remove_rpmsg_device(struct qcom_glink *glink, struct glink_channel *channel)
+{
+	struct rpmsg_channel_info chinfo;
+
+	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;
+}
+
+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 */
+	qcom_glink_remove_rpmsg_device(glink, channel);
+
+	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);
+
+	WRITE_ONCE(channel->intent_req_result, -1);
+	WRITE_ONCE(channel->intent_received, false);
+
+	cmd.id = GLINK_CMD_RX_INTENT_REQ;
+	cmd.cid = channel->lcid;
+	cmd.size = size;
+
+	trace_qcom_glink_cmd_rx_intent_req_tx(glink->label, channel->name,
+					      channel->lcid, channel->rcid,
+					      cmd.size);
+
+	ret = qcom_glink_tx(glink, &cmd, sizeof(cmd), NULL, 0, true);
+	if (ret)
+		goto unlock;
+
+	ret = wait_event_timeout(channel->intent_req_wq,
+				 READ_ONCE(channel->intent_req_result) == 0 ||
+				 (READ_ONCE(channel->intent_req_result) > 0 &&
+				  READ_ONCE(channel->intent_received)) ||
+				 glink->abort_tx,
+				 10 * HZ);
+	if (!ret) {
+		dev_err(glink->dev, "intent request timed out\n");
+		ret = -ETIMEDOUT;
+	} else if (glink->abort_tx) {
+		ret = -ECANCELED;
+	} else {
+		ret = READ_ONCE(channel->intent_req_result) ? 0 : -EAGAIN;
+	}
+
+unlock:
+	mutex_unlock(&channel->intent_req_lock);
+	return ret;
+}
+
+static int __qcom_glink_send(struct glink_channel *channel,
+			     const 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_hdr msg;
+		__le32 chunk_size;
+		__le32 left_size;
+	} __packed req;
+	int ret;
+	unsigned long flags;
+	int chunk_size = len;
+	size_t offset = 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;
+	}
+
+	while (offset < len) {
+		chunk_size = len - offset;
+		if (chunk_size > SZ_8K && wait)
+			chunk_size = SZ_8K;
+
+		req.msg.cmd = cpu_to_le16(offset == 0 ? GLINK_CMD_TX_DATA : GLINK_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(len - offset - chunk_size);
+
+		trace_qcom_glink_cmd_tx_data_tx(glink->label, channel->name,
+						channel->lcid, channel->rcid,
+						iid, chunk_size,
+						len - offset - chunk_size,
+						offset > 0);
+
+		ret = qcom_glink_tx(glink, &req, sizeof(req), data + offset, chunk_size, wait);
+		if (ret) {
+			/* Mark intent available if we failed */
+			if (intent)
+				intent->in_use = false;
+			return ret;
+		}
+
+		offset += chunk_size;
+	}
+
+	return 0;
+}
+
+static int qcom_glink_send(struct rpmsg_endpoint *ept, const 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, const 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, const 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, const 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,
+	.set_flow_control = qcom_glink_set_flow_control,
+};
+
+static void qcom_glink_rpdev_release(struct device *dev)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+
+	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;
+	}
+
+	trace_qcom_glink_cmd_open_rx(glink->label, name, channel->lcid, rcid);
+
+	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_obj(*rpdev);
+		if (!rpdev) {
+			ret = -ENOMEM;
+			goto rcid_remove;
+		}
+
+		rpdev->ept = &channel->ept;
+		strscpy(rpdev->id.name, name);
+		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 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);
+
+	trace_qcom_glink_cmd_close_rx(glink->label, channel ? channel->name : NULL,
+				      channel ? channel->lcid : 0, rcid);
+	if (WARN(!channel, "close request on unknown channel\n"))
+		return;
+
+	/* cancel pending rx_done work */
+	cancel_work_sync(&channel->intent_work);
+
+	qcom_glink_remove_rpmsg_device(glink, channel);
+
+	qcom_glink_send_close_ack(glink, channel);
+
+	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 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);
+
+	trace_qcom_glink_cmd_close_ack_rx(glink->label, channel ? channel->name : NULL,
+					  lcid, channel ? channel->rcid : 0);
+	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 */
+	qcom_glink_remove_rpmsg_device(glink, channel);
+
+	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 = container_of(&dcmd->msg, struct glink_msg, hdr);
+		cmd = le16_to_cpu(msg->cmd);
+		param1 = le16_to_cpu(msg->param1);
+		param2 = le32_to_cpu(msg->param2);
+
+		switch (cmd) {
+		case GLINK_CMD_VERSION:
+			qcom_glink_receive_version(glink, param1, param2);
+			break;
+		case GLINK_CMD_VERSION_ACK:
+			qcom_glink_receive_version_ack(glink, param1, param2);
+			break;
+		case GLINK_CMD_OPEN:
+			qcom_glink_rx_open(glink, param1, msg->data);
+			break;
+		case GLINK_CMD_CLOSE:
+			qcom_glink_rx_close(glink, param1);
+			break;
+		case GLINK_CMD_CLOSE_ACK:
+			qcom_glink_rx_close_ack(glink, param1);
+			break;
+		case GLINK_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);
+}
+
+static int qcom_glink_create_chrdev(struct qcom_glink *glink)
+{
+	struct rpmsg_device *rpdev;
+	struct glink_channel *channel;
+
+	rpdev = kzalloc_obj(*rpdev);
+	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 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);
+
+	ret = of_property_read_string(dev->of_node, "label", &glink->label);
+	if (ret < 0)
+		glink->label = dev->of_node->name;
+
+	glink->dev->groups = qcom_glink_groups;
+
+	ret = device_add_groups(dev, qcom_glink_groups);
+	if (ret)
+		dev_err(dev, "failed to add groups\n");
+
+	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;
+	unsigned long flags;
+	int cid;
+	int ret;
+
+	qcom_glink_cancel_rx_work(glink);
+
+	/* Fail all attempts at sending messages */
+	spin_lock_irqsave(&glink->tx_lock, flags);
+	glink->abort_tx = true;
+	wake_up_all(&glink->tx_avail_notify);
+	spin_unlock_irqrestore(&glink->tx_lock, flags);
+
+	/* Abort any senders waiting for intent requests */
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	idr_for_each_entry(&glink->lcids, channel, cid)
+		qcom_glink_intent_req_abort(channel);
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+
+	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);
+}
+EXPORT_SYMBOL_GPL(qcom_glink_native_remove);
+
+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..8dbec24de
--- /dev/null
+++ b/drivers/rpmsg/qcom_glink_native.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2016-2017, Linaro Ltd
+ */
+
+#ifndef __QCOM_GLINK_NATIVE_H__
+#define __QCOM_GLINK_NATIVE_H__
+
+#include <linux/types.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 (*peek)(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);
+	void (*kick)(struct qcom_glink_pipe *glink_pipe);
+};
+
+struct device;
+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_rx(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..e3ba2c63a
--- /dev/null
+++ b/drivers/rpmsg/qcom_glink_rpm.c
@@ -0,0 +1,405 @@
+// 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/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;
+};
+
+struct glink_rpm {
+	struct qcom_glink *glink;
+
+	int irq;
+
+	struct mbox_client mbox_client;
+	struct mbox_chan *mbox_chan;
+
+	struct glink_rpm_pipe rx_pipe;
+	struct glink_rpm_pipe tx_pipe;
+};
+
+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_peek(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 void glink_rpm_tx_kick(struct qcom_glink_pipe *glink_pipe)
+{
+	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
+	struct glink_rpm *rpm = container_of(pipe, struct glink_rpm, tx_pipe);
+
+	mbox_send_message(rpm->mbox_chan, NULL);
+	mbox_client_txdone(rpm->mbox_chan, 0);
+}
+
+static irqreturn_t qcom_glink_rpm_intr(int irq, void *data)
+{
+	struct glink_rpm *rpm = data;
+
+	qcom_glink_native_rx(rpm->glink);
+
+	return IRQ_HANDLED;
+}
+
+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 *rpm;
+	struct device_node *np;
+	void __iomem *msg_ram;
+	size_t msg_ram_size;
+	struct device *dev = &pdev->dev;
+	struct resource r;
+	int ret;
+
+	rpm = devm_kzalloc(&pdev->dev, sizeof(*rpm), GFP_KERNEL);
+	if (!rpm)
+		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,
+				  &rpm->rx_pipe, &rpm->tx_pipe);
+	if (ret)
+		return ret;
+
+	rpm->irq = of_irq_get(dev->of_node, 0);
+	ret = devm_request_irq(dev, rpm->irq, qcom_glink_rpm_intr,
+			       IRQF_NO_SUSPEND | IRQF_NO_AUTOEN,
+			       "glink-rpm", rpm);
+	if (ret) {
+		dev_err(dev, "failed to request IRQ\n");
+		return ret;
+	}
+
+	rpm->mbox_client.dev = dev;
+	rpm->mbox_client.knows_txdone = true;
+	rpm->mbox_chan = mbox_request_channel(&rpm->mbox_client, 0);
+	if (IS_ERR(rpm->mbox_chan))
+		return dev_err_probe(dev, PTR_ERR(rpm->mbox_chan), "failed to acquire IPC channel\n");
+
+	/* Pipe specific accessors */
+	rpm->rx_pipe.native.avail = glink_rpm_rx_avail;
+	rpm->rx_pipe.native.peek = glink_rpm_rx_peek;
+	rpm->rx_pipe.native.advance = glink_rpm_rx_advance;
+	rpm->tx_pipe.native.avail = glink_rpm_tx_avail;
+	rpm->tx_pipe.native.write = glink_rpm_tx_write;
+	rpm->tx_pipe.native.kick = glink_rpm_tx_kick;
+
+	writel(0, rpm->tx_pipe.head);
+	writel(0, rpm->rx_pipe.tail);
+
+	glink = qcom_glink_native_probe(dev,
+					0,
+					&rpm->rx_pipe.native,
+					&rpm->tx_pipe.native,
+					true);
+	if (IS_ERR(glink)) {
+		mbox_free_channel(rpm->mbox_chan);
+		return PTR_ERR(glink);
+	}
+
+	rpm->glink = glink;
+
+	platform_set_drvdata(pdev, rpm);
+
+	enable_irq(rpm->irq);
+
+	return 0;
+}
+
+static void glink_rpm_remove(struct platform_device *pdev)
+{
+	struct glink_rpm *rpm = platform_get_drvdata(pdev);
+	struct qcom_glink *glink = rpm->glink;
+
+	disable_irq(rpm->irq);
+
+	qcom_glink_native_remove(glink);
+
+	mbox_free_channel(rpm->mbox_chan);
+}
+
+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..62adc4db2
--- /dev/null
+++ b/drivers/rpmsg/qcom_glink_smem.c
@@ -0,0 +1,378 @@
+// 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/of_irq.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/mailbox_client.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 qcom_glink_smem {
+	struct device dev;
+
+	int irq;
+	struct qcom_glink *glink;
+
+	struct mbox_client mbox_client;
+	struct mbox_chan *mbox_chan;
+
+	u32 remote_pid;
+};
+
+struct glink_smem_pipe {
+	struct qcom_glink_pipe native;
+
+	__le32 *tail;
+	__le32 *head;
+
+	void *fifo;
+
+	struct qcom_glink_smem *smem;
+};
+
+#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);
+	struct qcom_glink_smem *smem = pipe->smem;
+	size_t len;
+	void *fifo;
+	u32 head;
+	u32 tail;
+
+	if (!pipe->fifo) {
+		fifo = qcom_smem_get(smem->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_peek(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 glink_smem_tx_kick(struct qcom_glink_pipe *glink_pipe)
+{
+	struct glink_smem_pipe *pipe = to_smem_pipe(glink_pipe);
+	struct qcom_glink_smem *smem = pipe->smem;
+
+	mbox_send_message(smem->mbox_chan, NULL);
+	mbox_client_txdone(smem->mbox_chan, 0);
+}
+
+static irqreturn_t qcom_glink_smem_intr(int irq, void *data)
+{
+	struct qcom_glink_smem *smem = data;
+
+	qcom_glink_native_rx(smem->glink);
+
+	return IRQ_HANDLED;
+}
+
+static void qcom_glink_smem_release(struct device *dev)
+{
+	struct qcom_glink_smem *smem = container_of(dev, struct qcom_glink_smem, dev);
+
+	kfree(smem);
+}
+
+struct qcom_glink_smem *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_smem *smem;
+	struct qcom_glink *glink;
+	struct device *dev;
+	u32 remote_pid;
+	__le32 *descs;
+	size_t size;
+	int ret;
+
+	smem = kzalloc_obj(*smem);
+	if (!smem)
+		return ERR_PTR(-ENOMEM);
+
+	dev = &smem->dev;
+
+	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;
+	}
+
+	smem->remote_pid = remote_pid;
+
+	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;
+	}
+
+	smem->irq = of_irq_get(smem->dev.of_node, 0);
+	ret = devm_request_irq(&smem->dev, smem->irq, qcom_glink_smem_intr,
+			       IRQF_NO_SUSPEND | IRQF_NO_AUTOEN,
+			       "glink-smem", smem);
+	if (ret) {
+		dev_err(&smem->dev, "failed to request IRQ\n");
+		goto err_put_dev;
+	}
+
+	smem->mbox_client.dev = &smem->dev;
+	smem->mbox_client.knows_txdone = true;
+	smem->mbox_chan = mbox_request_channel(&smem->mbox_client, 0);
+	if (IS_ERR(smem->mbox_chan)) {
+		ret = dev_err_probe(&smem->dev, PTR_ERR(smem->mbox_chan),
+				    "failed to acquire IPC channel\n");
+		goto err_put_dev;
+	}
+
+	rx_pipe->smem = smem;
+	rx_pipe->native.avail = glink_smem_rx_avail;
+	rx_pipe->native.peek = glink_smem_rx_peek;
+	rx_pipe->native.advance = glink_smem_rx_advance;
+
+	tx_pipe->smem = smem;
+	tx_pipe->native.avail = glink_smem_tx_avail;
+	tx_pipe->native.write = glink_smem_tx_write;
+	tx_pipe->native.kick = glink_smem_tx_kick;
+
+	*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_free_mbox;
+	}
+
+	smem->glink = glink;
+
+	enable_irq(smem->irq);
+
+	return smem;
+
+err_free_mbox:
+	mbox_free_channel(smem->mbox_chan);
+
+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_smem *smem)
+{
+	struct qcom_glink *glink = smem->glink;
+
+	disable_irq(smem->irq);
+
+	qcom_glink_native_remove(glink);
+
+	mbox_free_channel(smem->mbox_chan);
+	device_unregister(&smem->dev);
+}
+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..e71d3716c
--- /dev/null
+++ b/drivers/rpmsg/qcom_glink_ssr.c
@@ -0,0 +1,168 @@
+// 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));
+	strscpy(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" },
+	{}
+};
+MODULE_DEVICE_TABLE(rpmsg, qcom_glink_ssr_match);
+
+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_glink_trace.h b/drivers/rpmsg/qcom_glink_trace.h
new file mode 100644
index 000000000..668bdea1d
--- /dev/null
+++ b/drivers/rpmsg/qcom_glink_trace.h
@@ -0,0 +1,406 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM qcom_glink
+
+#if !defined(__QCOM_GLINK_TRACE_H__) || defined(TRACE_HEADER_MULTI_READ)
+#define __QCOM_GLINK_TRACE_H__
+
+#include <linux/tracepoint.h>
+#include "qcom_glink_native.h"
+
+
+TRACE_EVENT(qcom_glink_cmd_version,
+	TP_PROTO(const char *remote, unsigned int version, unsigned int features, bool tx),
+	TP_ARGS(remote, version, features, tx),
+	TP_STRUCT__entry(
+		__string(remote, remote)
+		__field(u32, version)
+		__field(u32, features)
+		__field(bool, tx)
+	),
+	TP_fast_assign(
+		__assign_str(remote);
+		__entry->version = version;
+		__entry->features = features;
+		__entry->tx = tx;
+	),
+	TP_printk("%s remote: %s version: %u features: %#x",
+		  __entry->tx ? "tx" : "rx",
+		  __get_str(remote),
+		  __entry->version,
+		  __entry->features
+	)
+);
+#define trace_qcom_glink_cmd_version_tx(...) trace_qcom_glink_cmd_version(__VA_ARGS__, true)
+#define trace_qcom_glink_cmd_version_rx(...) trace_qcom_glink_cmd_version(__VA_ARGS__, false)
+
+TRACE_EVENT(qcom_glink_cmd_version_ack,
+	TP_PROTO(const char *remote, unsigned int version, unsigned int features, bool tx),
+	TP_ARGS(remote, version, features, tx),
+	TP_STRUCT__entry(
+		__string(remote, remote)
+		__field(u32, version)
+		__field(u32, features)
+		__field(bool, tx)
+	),
+	TP_fast_assign(
+		__assign_str(remote);
+		__entry->version = version;
+		__entry->features = features;
+		__entry->tx = tx;
+	),
+	TP_printk("%s remote: %s version: %u features: %#x",
+		  __entry->tx ? "tx" : "rx",
+		  __get_str(remote),
+		  __entry->version,
+		  __entry->features
+	)
+);
+#define trace_qcom_glink_cmd_version_ack_tx(...) trace_qcom_glink_cmd_version_ack(__VA_ARGS__, true)
+#define trace_qcom_glink_cmd_version_ack_rx(...) trace_qcom_glink_cmd_version_ack(__VA_ARGS__, false)
+
+TRACE_EVENT(qcom_glink_cmd_open,
+	TP_PROTO(const char *remote, const char *channel, u16 lcid, u16 rcid, bool tx),
+	TP_ARGS(remote, channel, lcid, rcid, tx),
+	TP_STRUCT__entry(
+		__string(remote, remote)
+		__string(channel, channel)
+		__field(u16, lcid)
+		__field(u16, rcid)
+		__field(bool, tx)
+	),
+	TP_fast_assign(
+		__assign_str(remote);
+		__assign_str(channel);
+		__entry->lcid = lcid;
+		__entry->rcid = rcid;
+		__entry->tx = tx;
+	),
+	TP_printk("%s remote: %s channel: %s[%u/%u]",
+		  __entry->tx ? "tx" : "rx",
+		  __get_str(remote),
+		  __get_str(channel),
+		  __entry->lcid,
+		  __entry->rcid
+	)
+);
+#define trace_qcom_glink_cmd_open_tx(...) trace_qcom_glink_cmd_open(__VA_ARGS__, true)
+#define trace_qcom_glink_cmd_open_rx(...) trace_qcom_glink_cmd_open(__VA_ARGS__, false)
+
+TRACE_EVENT(qcom_glink_cmd_close,
+	TP_PROTO(const char *remote, const char *channel, u16 lcid, u16 rcid, bool tx),
+	TP_ARGS(remote, channel, lcid, rcid, tx),
+	TP_STRUCT__entry(
+		__string(remote, remote)
+		__string(channel, channel)
+		__field(u16, lcid)
+		__field(u16, rcid)
+		__field(bool, tx)
+	),
+	TP_fast_assign(
+		__assign_str(remote);
+		__assign_str(channel);
+		__entry->lcid = lcid;
+		__entry->rcid = rcid;
+		__entry->tx = tx;
+	),
+	TP_printk("%s remote: %s channel: %s[%u/%u]",
+		  __entry->tx ? "tx" : "rx",
+		  __get_str(remote),
+		  __get_str(channel),
+		  __entry->lcid,
+		  __entry->rcid
+	)
+);
+#define trace_qcom_glink_cmd_close_tx(...) trace_qcom_glink_cmd_close(__VA_ARGS__, true)
+#define trace_qcom_glink_cmd_close_rx(...) trace_qcom_glink_cmd_close(__VA_ARGS__, false)
+
+TRACE_EVENT(qcom_glink_cmd_open_ack,
+	TP_PROTO(const char *remote, const char *channel, u16 lcid, u16 rcid, bool tx),
+	TP_ARGS(remote, channel, lcid, rcid, tx),
+	TP_STRUCT__entry(
+		__string(remote, remote)
+		__string(channel, channel)
+		__field(u16, lcid)
+		__field(u16, rcid)
+		__field(bool, tx)
+	),
+	TP_fast_assign(
+		__assign_str(remote);
+		__assign_str(channel);
+		__entry->lcid = lcid;
+		__entry->rcid = rcid;
+		__entry->tx = tx;
+	),
+	TP_printk("%s remote: %s channel: %s[%u/%u]",
+		  __entry->tx ? "tx" : "rx",
+		  __get_str(remote),
+		  __get_str(channel),
+		  __entry->lcid,
+		  __entry->rcid
+	)
+);
+#define trace_qcom_glink_cmd_open_ack_tx(...) trace_qcom_glink_cmd_open_ack(__VA_ARGS__, true)
+#define trace_qcom_glink_cmd_open_ack_rx(...) trace_qcom_glink_cmd_open_ack(__VA_ARGS__, false)
+
+TRACE_EVENT(qcom_glink_cmd_intent,
+	TP_PROTO(const char *remote, const char *channel, u16 lcid, u16 rcid, size_t count, size_t size, u32 liid, bool tx),
+	TP_ARGS(remote, channel, lcid, rcid, count, size, liid, tx),
+	TP_STRUCT__entry(
+		__string(remote, remote)
+		__string(channel, channel)
+		__field(u16, lcid)
+		__field(u16, rcid)
+		__field(u32, count)
+		__field(u32, size)
+		__field(u32, liid)
+		__field(bool, tx)
+	),
+	TP_fast_assign(
+		__assign_str(remote);
+		__assign_str(channel);
+		__entry->lcid = lcid;
+		__entry->rcid = rcid;
+		__entry->count = count;
+		__entry->size = size;
+		__entry->liid = liid;
+		__entry->tx = tx;
+	),
+	TP_printk("%s remote: %s channel: %s[%u/%u] count: %d [size: %d liid: %d]",
+		  __entry->tx ? "tx" : "rx",
+		  __get_str(remote),
+		  __get_str(channel),
+		  __entry->lcid,
+		  __entry->rcid,
+		  __entry->count,
+		  __entry->size,
+		  __entry->liid
+	)
+);
+#define trace_qcom_glink_cmd_intent_tx(...) trace_qcom_glink_cmd_intent(__VA_ARGS__, true)
+#define trace_qcom_glink_cmd_intent_rx(...) trace_qcom_glink_cmd_intent(__VA_ARGS__, false)
+
+TRACE_EVENT(qcom_glink_cmd_rx_done,
+	TP_PROTO(const char *remote, const char *channel, u16 lcid, u16 rcid, u32 iid, bool reuse, bool tx),
+	TP_ARGS(remote, channel, lcid, rcid, iid, reuse, tx),
+	TP_STRUCT__entry(
+		__string(remote, remote)
+		__string(channel, channel)
+		__field(u16, lcid)
+		__field(u16, rcid)
+		__field(u32, iid)
+		__field(bool, reuse)
+		__field(bool, tx)
+	),
+	TP_fast_assign(
+		__assign_str(remote);
+		__assign_str(channel);
+		__entry->lcid = lcid;
+		__entry->rcid = rcid;
+		__entry->iid = iid;
+		__entry->reuse = reuse;
+		__entry->tx = tx;
+	),
+	TP_printk("%s remote: %s channel: %s[%u/%u] iid: %d reuse: %d",
+		  __entry->tx ? "tx" : "rx",
+		  __get_str(remote),
+		  __get_str(channel),
+		  __entry->lcid,
+		  __entry->rcid,
+		  __entry->iid,
+		  __entry->reuse
+	)
+);
+#define trace_qcom_glink_cmd_rx_done_tx(...) trace_qcom_glink_cmd_rx_done(__VA_ARGS__, true)
+#define trace_qcom_glink_cmd_rx_done_rx(...) trace_qcom_glink_cmd_rx_done(__VA_ARGS__, false)
+
+TRACE_EVENT(qcom_glink_cmd_rx_intent_req,
+	TP_PROTO(const char *remote, const char *channel, u16 lcid, u16 rcid, size_t size, bool tx),
+	TP_ARGS(remote, channel, lcid, rcid, size, tx),
+	TP_STRUCT__entry(
+		__string(remote, remote)
+		__string(channel, channel)
+		__field(u16, lcid)
+		__field(u16, rcid)
+		__field(u32, size)
+		__field(bool, tx)
+	),
+	TP_fast_assign(
+		__assign_str(remote);
+		__assign_str(channel);
+		__entry->lcid = lcid;
+		__entry->rcid = rcid;
+		__entry->size = size;
+		__entry->tx = tx;
+	),
+	TP_printk("%s remote: %s channel: %s[%u/%u] size: %d",
+		  __entry->tx ? "tx" : "rx",
+		  __get_str(remote),
+		  __get_str(channel),
+		  __entry->lcid,
+		  __entry->rcid,
+		  __entry->size
+	)
+);
+#define trace_qcom_glink_cmd_rx_intent_req_tx(...) trace_qcom_glink_cmd_rx_intent_req(__VA_ARGS__, true)
+#define trace_qcom_glink_cmd_rx_intent_req_rx(...) trace_qcom_glink_cmd_rx_intent_req(__VA_ARGS__, false)
+
+TRACE_EVENT(qcom_glink_cmd_rx_intent_req_ack,
+	TP_PROTO(const char *remote, const char *channel, u16 lcid, u16 rcid, bool granted, bool tx),
+	TP_ARGS(remote, channel, lcid, rcid, granted, tx),
+	TP_STRUCT__entry(
+		__string(remote, remote)
+		__string(channel, channel)
+		__field(u16, lcid)
+		__field(u16, rcid)
+		__field(bool, granted)
+		__field(bool, tx)
+	),
+	TP_fast_assign(
+		__assign_str(remote);
+		__assign_str(channel);
+		__entry->lcid = lcid;
+		__entry->rcid = rcid;
+		__entry->granted = granted;
+		__entry->tx = tx;
+	),
+	TP_printk("%s remote: %s channel: %s[%u/%u] granted: %d",
+		  __entry->tx ? "tx" : "rx",
+		  __get_str(remote),
+		  __get_str(channel),
+		  __entry->lcid,
+		  __entry->rcid,
+		  __entry->granted
+	)
+);
+#define trace_qcom_glink_cmd_rx_intent_req_ack_tx(...) trace_qcom_glink_cmd_rx_intent_req_ack(__VA_ARGS__, true)
+#define trace_qcom_glink_cmd_rx_intent_req_ack_rx(...) trace_qcom_glink_cmd_rx_intent_req_ack(__VA_ARGS__, false)
+
+TRACE_EVENT(qcom_glink_cmd_tx_data,
+	TP_PROTO(const char *remote, const char *channel, u16 lcid, u16 rcid, u32 iid, u32 chunk_size, u32 left_size, bool cont, bool tx),
+	TP_ARGS(remote, channel, lcid, rcid, iid, chunk_size, left_size, cont, tx),
+	TP_STRUCT__entry(
+		__string(remote, remote)
+		__string(channel, channel)
+		__field(u16, lcid)
+		__field(u16, rcid)
+		__field(u32, iid)
+		__field(u32, chunk_size)
+		__field(u32, left_size)
+		__field(bool, cont)
+		__field(bool, tx)
+	),
+	TP_fast_assign(
+		__assign_str(remote);
+		__assign_str(channel);
+		__entry->lcid = lcid;
+		__entry->rcid = rcid;
+		__entry->iid = iid;
+		__entry->chunk_size = chunk_size;
+		__entry->left_size = left_size;
+		__entry->cont = cont;
+		__entry->tx = tx;
+	),
+	TP_printk("%s remote: %s channel: %s[%u/%u] iid: %d chunk_size: %d left_size: %d cont: %d",
+		  __entry->tx ? "tx" : "rx",
+		  __get_str(remote),
+		  __get_str(channel),
+		  __entry->lcid,
+		  __entry->rcid,
+		  __entry->iid,
+		  __entry->chunk_size,
+		  __entry->left_size,
+		  __entry->cont
+	)
+);
+#define trace_qcom_glink_cmd_tx_data_tx(...) trace_qcom_glink_cmd_tx_data(__VA_ARGS__, true)
+#define trace_qcom_glink_cmd_tx_data_rx(...) trace_qcom_glink_cmd_tx_data(__VA_ARGS__, false)
+
+TRACE_EVENT(qcom_glink_cmd_close_ack,
+	TP_PROTO(const char *remote, const char *channel, u16 lcid, u16 rcid, bool tx),
+	TP_ARGS(remote, channel, lcid, rcid, tx),
+	TP_STRUCT__entry(
+		__string(remote, remote)
+		__string(channel, channel)
+		__field(u16, lcid)
+		__field(u16, rcid)
+		__field(bool, tx)
+	),
+	TP_fast_assign(
+		__assign_str(remote);
+		__assign_str(channel);
+		__entry->lcid = lcid;
+		__entry->rcid = rcid;
+		__entry->tx = tx;
+	),
+	TP_printk("%s remote: %s channel: %s[%u/%u]",
+		  __entry->tx ? "tx" : "rx",
+		  __get_str(remote),
+		  __get_str(channel),
+		  __entry->lcid,
+		  __entry->rcid
+	)
+);
+#define trace_qcom_glink_cmd_close_ack_tx(...) trace_qcom_glink_cmd_close_ack(__VA_ARGS__, true)
+#define trace_qcom_glink_cmd_close_ack_rx(...) trace_qcom_glink_cmd_close_ack(__VA_ARGS__, false)
+
+TRACE_EVENT(qcom_glink_cmd_read_notif,
+	TP_PROTO(const char *remote, bool tx),
+	TP_ARGS(remote, tx),
+	TP_STRUCT__entry(
+		__string(remote, remote)
+		__field(bool, tx)
+	),
+	TP_fast_assign(
+		__assign_str(remote);
+		__entry->tx = tx;
+	),
+	TP_printk("%s remote: %s",
+		  __entry->tx ? "tx" : "rx",
+		  __get_str(remote)
+	)
+);
+#define trace_qcom_glink_cmd_read_notif_tx(...) trace_qcom_glink_cmd_read_notif(__VA_ARGS__, true)
+#define trace_qcom_glink_cmd_read_notif_rx(...) trace_qcom_glink_cmd_read_notif(__VA_ARGS__, false)
+
+TRACE_EVENT(qcom_glink_cmd_signal,
+	TP_PROTO(const char *remote, const char *channel, u16 lcid, u16 rcid, unsigned int signals, bool tx),
+	TP_ARGS(remote, channel, lcid, rcid, signals, tx),
+	TP_STRUCT__entry(
+		__string(remote, remote)
+		__string(channel, channel)
+		__field(u16, lcid)
+		__field(u16, rcid)
+		__field(u32, signals)
+		__field(bool, tx)
+	),
+	TP_fast_assign(
+		__assign_str(remote);
+		__assign_str(channel);
+		__entry->lcid = lcid;
+		__entry->rcid = rcid;
+		__entry->signals = signals;
+		__entry->tx = tx;
+	),
+	TP_printk("%s remote: %s channel: %s[%u/%u] signals: %#x",
+		  __entry->tx ? "tx" : "rx",
+		  __get_str(remote),
+		  __get_str(channel),
+		  __entry->lcid,
+		  __entry->rcid,
+		  __entry->signals
+	)
+);
+#define trace_qcom_glink_cmd_signal_tx(...) trace_qcom_glink_cmd_signal(__VA_ARGS__, true)
+#define trace_qcom_glink_cmd_signal_rx(...) trace_qcom_glink_cmd_signal(__VA_ARGS__, false)
+
+#endif
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE qcom_glink_trace
+
+#include <trace/define_trace.h>
diff --git a/drivers/rpmsg/qcom_smd.c b/drivers/rpmsg/qcom_smd.c
new file mode 100644
index 000000000..3ac863f40
--- /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 = 0;
+
+	/* 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_obj(*qsept);
+	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, const 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, const 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, const 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, const 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_obj(*qsdev);
+	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(rpdev->id.name, channel->name);
+	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_obj(*qsdev);
+	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_obj(*channel);
+	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) != -ENOENT) {
+			ret = dev_err_probe(dev, PTR_ERR(edge->mbox_chan),
+					    "failed to acquire IPC mailbox\n");
+			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);
+			dev_err(dev, "failed to get regmap from syscon: %d\n", ret);
+			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;
+
+	if (!qcom_smem_is_available())
+		return ERR_PTR(-EPROBE_DEFER);
+
+	edge = kzalloc_obj(*edge);
+	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)
+		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
+ */
+void 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);
+}
+EXPORT_SYMBOL(qcom_smd_unregister_edge);
+
+static int qcom_smd_probe(struct platform_device *pdev)
+{
+	struct device_node *node;
+
+	if (!qcom_smem_is_available())
+		return -EPROBE_DEFER;
+
+	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);
+
+	qcom_smd_unregister_edge(edge);
+
+	return 0;
+}
+
+/*
+ * 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 void qcom_smd_remove(struct platform_device *pdev)
+{
+	/*
+	 * qcom_smd_remove_edge always returns zero, so there is no need to
+	 * check the return value of device_for_each_child.
+	 */
+	device_for_each_child(&pdev->dev, NULL, qcom_smd_remove_edge);
+}
+
+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..bff5aefee
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -0,0 +1,582 @@
+// 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.
+ * @remote_flow_restricted: to indicate if the remote has requested for flow to be limited
+ * @remote_flow_updated: to indicate if the flow control has been requested
+ */
+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;
+
+	bool remote_flow_restricted;
+	bool remote_flow_updated;
+};
+
+int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
+{
+	struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
+
+	mutex_lock(&eptdev->ept_lock);
+	eptdev->rpdev = NULL;
+	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;
+
+	if (!eptdev)
+		return 0;
+
+	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_ept_flow_cb(struct rpmsg_device *rpdev, void *priv, bool enable)
+{
+	struct rpmsg_eptdev *eptdev = priv;
+
+	if (!eptdev)
+		return 0;
+
+	eptdev->remote_flow_restricted = enable;
+	eptdev->remote_flow_updated = true;
+
+	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;
+	}
+
+	if (!eptdev->rpdev) {
+		mutex_unlock(&eptdev->ept_lock);
+		return -ENETRESET;
+	}
+
+	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;
+	}
+
+	ept->flow_cb = rpmsg_ept_flow_cb;
+	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);
+	eptdev->remote_flow_updated = false;
+
+	/* 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;
+
+	if (eptdev->remote_flow_updated)
+		mask |= EPOLLPRI;
+
+	mutex_lock(&eptdev->ept_lock);
+	mask |= rpmsg_poll(eptdev->ept, filp, wait);
+	mutex_unlock(&eptdev->ept_lock);
+
+	return mask;
+}
+
+static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
+			       unsigned long arg)
+{
+	struct rpmsg_eptdev *eptdev = fp->private_data;
+
+	bool set;
+	int ret;
+
+	switch (cmd) {
+	case RPMSG_GET_OUTGOING_FLOWCONTROL:
+		eptdev->remote_flow_updated = false;
+		ret = put_user(eptdev->remote_flow_restricted, (int __user *)arg);
+		break;
+	case RPMSG_SET_INCOMING_FLOWCONTROL:
+		if (arg > 1) {
+			ret = -EINVAL;
+			break;
+		}
+		set = !!arg;
+		ret = rpmsg_set_flow_control(eptdev->ept, set, eptdev->chinfo.dst);
+		break;
+	case RPMSG_DESTROY_EPT_IOCTL:
+		/* Don't allow to destroy a default endpoint. */
+		if (eptdev->default_ept) {
+			ret = -EINVAL;
+			break;
+		}
+		ret = rpmsg_chrdev_eptdev_destroy(&eptdev->dev, NULL);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+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_free(&rpmsg_ept_ida, dev->id);
+	ida_free(&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_obj(*eptdev);
+	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_alloc_max(&rpmsg_minor_ida, RPMSG_DEV_MAX - 1, GFP_KERNEL);
+	if (ret < 0)
+		goto free_eptdev;
+	dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
+
+	ret = ida_alloc(&rpmsg_ept_ida, 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_free(&rpmsg_ept_ida, dev->id);
+free_minor_ida:
+	ida_free(&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;
+	int ret;
+
+	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;
+
+	ret = rpmsg_chrdev_eptdev_add(eptdev, chinfo);
+
+	if (ret)
+		return ret;
+	/*
+	 * The rpmsg_ept_cb uses *priv parameter to get its rpmsg_eptdev context.
+	 * Stored it in default_ept *priv field.
+	 */
+	eptdev->default_ept->priv = eptdev;
+
+	return 0;
+}
+
+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" },
+	{ .name	= "rpmsg_chrdev" },
+	{ },
+};
+MODULE_DEVICE_TABLE(rpmsg, rpmsg_chrdev_id_table);
+
+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_DESCRIPTION("RPMSG device interface");
+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..c56f69c22
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_core.c
@@ -0,0 +1,638 @@
+// 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"
+
+const struct class rpmsg_class = {
+	.name = "rpmsg",
+};
+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, const 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, const 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_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, const 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, const 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_set_flow_control() - request remote to pause/resume transmission
+ * @ept:	the rpmsg endpoint
+ * @pause:	pause transmission
+ * @dst:	destination address of the endpoint
+ *
+ * Return: 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_set_flow_control(struct rpmsg_endpoint *ept, bool pause, u32 dst)
+{
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->set_flow_control)
+		return -EOPNOTSUPP;
+
+	return ept->ops->set_flow_control(ept, pause, dst);
+}
+EXPORT_SYMBOL_GPL(rpmsg_set_flow_control);
+
+/**
+ * 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, const void *data)
+{
+	const 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);
+
+/* 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");
+
+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,
+	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, const struct device_driver *drv)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+	const struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
+	const struct rpmsg_device_id *ids = rpdrv->id_table;
+	unsigned int i;
+	int ret;
+
+	ret = device_match_driver_override(dev, drv);
+	if (ret >= 0)
+		return ret;
+
+	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(const struct device *dev, struct kobj_uevent_env *env)
+{
+	const 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, PD_FLAG_ATTACH_POWER_ON |
+					PD_FLAG_DETACH_POWER_OFF);
+	if (err)
+		goto out;
+
+	if (rpdrv->callback) {
+		strscpy(chinfo.name, rpdev->id.name, sizeof(chinfo.name));
+		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;
+
+		ept->flow_cb = rpdrv->flowcontrol;
+	}
+
+	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);
+
+	if (rpdev->ept)
+		rpmsg_destroy_ept(rpdev->ept);
+}
+
+static const struct bus_type rpmsg_bus = {
+	.name		= "rpmsg",
+	.match		= rpmsg_dev_match,
+	.dev_groups	= rpmsg_dev_groups,
+	.driver_override = true,
+	.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 = device_set_driver_override(dev, driver_override);
+		if (ret) {
+			dev_err(dev, "device_set_driver_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);
+		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;
+
+	ret = class_register(&rpmsg_class);
+	if (ret) {
+		pr_err("failed to register rpmsg class\n");
+		return ret;
+	}
+
+	ret = bus_register(&rpmsg_bus);
+	if (ret) {
+		pr_err("failed to register rpmsg bus: %d\n", ret);
+		class_unregister(&rpmsg_class);
+	}
+	return ret;
+}
+postcore_initcall(rpmsg_init);
+
+static void __exit rpmsg_fini(void)
+{
+	bus_unregister(&rpmsg_bus);
+	class_unregister(&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..5c19188d0
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_ctrl.c
@@ -0,0 +1,245 @@
+// 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_free(&rpmsg_ctrl_ida, dev->id);
+	ida_free(&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_obj(*ctrldev);
+	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_alloc_max(&rpmsg_minor_ida, RPMSG_DEV_MAX - 1, GFP_KERNEL);
+	if (ret < 0)
+		goto free_ctrldev;
+	dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
+
+	ret = ida_alloc(&rpmsg_ctrl_ida, 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_free(&rpmsg_ctrl_ida, dev->id);
+free_minor_ida:
+	ida_free(&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;
+
+	mutex_lock(&ctrldev->ctrl_lock);
+	/* 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);
+	mutex_unlock(&ctrldev->ctrl_lock);
+
+	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..a8b7065fd
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_internal.h
@@ -0,0 +1,96 @@
+/* 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_const(d, struct rpmsg_driver, drv)
+
+extern const 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
+ * @trysend:		see @rpmsg_trysend(), required
+ * @trysendto:		see @rpmsg_trysendto(), optional
+ * @poll:		see @rpmsg_poll(), optional
+ * @set_flow_control:	see @rpmsg_set_flow_control(), 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, const void *data, int len);
+	int (*sendto)(struct rpmsg_endpoint *ept, const void *data, int len, u32 dst);
+
+	int (*trysend)(struct rpmsg_endpoint *ept, const void *data, int len);
+	int (*trysendto)(struct rpmsg_endpoint *ept, const void *data, int len, u32 dst);
+	__poll_t (*poll)(struct rpmsg_endpoint *ept, struct file *filp,
+			     poll_table *wait);
+	int (*set_flow_control)(struct rpmsg_endpoint *ept, bool pause, u32 dst);
+	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..bde8c8d43
--- /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';
+
+	strscpy_pad(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..1b8bb0592
--- /dev/null
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -0,0 +1,1025 @@
+// 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 and sbufs, 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
+ *
+ * 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;
+};
+
+/* 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, const void *data, int len);
+static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, const void *data,
+			       int len, u32 dst);
+static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, const void *data,
+				int len);
+static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, const void *data,
+				  int len, u32 dst);
+static __poll_t virtio_rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
+				  poll_table *wait);
+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,
+	.trysend = virtio_rpmsg_trysend,
+	.trysendto = virtio_rpmsg_trysendto,
+	.poll = virtio_rpmsg_poll,
+	.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_obj(*ept);
+	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;
+
+		strscpy_pad(nsm.name, rpdev->id.name, sizeof(nsm.name));
+		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;
+
+		strscpy_pad(nsm.name, rpdev->id.name, sizeof(nsm.name));
+		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(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_obj(*vch);
+	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;
+
+	strscpy(rpdev->id.name, chinfo->name, sizeof(rpdev->id.name));
+
+	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;
+
+	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_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} 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,
+				     const 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) {
+		/*
+		 * 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));
+
+		/* 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, const 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, const 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_trysend(struct rpmsg_endpoint *ept, const 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, const 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 __poll_t virtio_rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
+				  poll_table *wait)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
+	struct virtproc_info *vrp = vch->vrp;
+	__poll_t mask = 0;
+
+	poll_wait(filp, &vrp->sendq, wait);
+
+	/* support multiple concurrent senders */
+	mutex_lock(&vrp->tx_lock);
+
+	/*
+	 * check for a free buffer, either:
+	 * - we haven't used all of the available transmit buffers (half of the
+	 *   allocated buffers are used for transmit, hence num_bufs / 2), or,
+	 * - we ask the virtqueue if there's a buffer available
+	 */
+	if (vrp->last_sbuf < vrp->num_bufs / 2 ||
+	    !virtqueue_enable_cb(vrp->svq))
+		mask |= EPOLLOUT;
+
+	mutex_unlock(&vrp->tx_lock);
+
+	return mask;
+}
+
+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_obj(*vch);
+	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)
+{
+	struct virtqueue_info vqs_info[] = {
+		{ "input", rpmsg_recv_done },
+		{ "output", rpmsg_xmit_done },
+	};
+	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_obj(*vrp);
+	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, vqs_info, 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 %p, 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 */
+	}
+
+	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_obj(*vch);
+		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,
+	.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");