rpmsg: glink: Move the common glink protocol implementation to glink_native.c

Move the common part of glink core protocol implementation to
glink_native.c that can be shared with the smem based glink
transport in the later patches.

Acked-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

1 files changed, 1017 insertions, 0 deletions

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
new file mode 100644
index 000000000000..ffdf88e436a7
--- /dev/null
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -0,0 +1,1017 @@
+/*
+ * Copyright (c) 2016-2017, Linaro Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#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 GLINK_NAME_SIZE		32
+
+#define RPM_GLINK_CID_MIN	1
+#define RPM_GLINK_CID_MAX	65536
+
+struct glink_msg {
+	__le16 cmd;
+	__le16 param1;
+	__le32 param2;
+	u8 data[];
+} __packed;
+
+/**
+ * struct glink_defer_cmd - deferred incoming control message
+ * @node:	list node
+ * @msg:	message header
+ * data:	payload of the message
+ *
+ * Copy of a received control message, to be added to @rx_queue and processed
+ * by @rx_work of @qcom_glink.
+ */
+struct glink_defer_cmd {
+	struct list_head node;
+
+	struct glink_msg msg;
+	u8 data[];
+};
+
+/**
+ * struct qcom_glink - driver context, relates to one remote subsystem
+ * @dev:	reference to the associated struct device
+ * @mbox_client: mailbox client
+ * @mbox_chan:  mailbox channel
+ * @rx_pipe:	pipe object for receive FIFO
+ * @tx_pipe:	pipe object for transmit FIFO
+ * @irq:	IRQ for signaling incoming events
+ * @rx_work:	worker for handling received control messages
+ * @rx_lock:	protects the @rx_queue
+ * @rx_queue:	queue of received control messages to be processed in @rx_work
+ * @tx_lock:	synchronizes operations on the tx fifo
+ * @idr_lock:	synchronizes @lcids and @rcids modifications
+ * @lcids:	idr of all channels with a known local channel id
+ * @rcids:	idr of all channels with a known remote channel id
+ */
+struct qcom_glink {
+	struct device *dev;
+
+	struct mbox_client mbox_client;
+	struct mbox_chan *mbox_chan;
+
+	struct qcom_glink_pipe *rx_pipe;
+	struct qcom_glink_pipe *tx_pipe;
+
+	int irq;
+
+	struct work_struct rx_work;
+	spinlock_t rx_lock;
+	struct list_head rx_queue;
+
+	struct mutex tx_lock;
+
+	struct mutex idr_lock;
+	struct idr lcids;
+	struct idr rcids;
+};
+
+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
+ * @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
+ */
+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;
+
+	void *buf;
+	int buf_offset;
+	int buf_size;
+
+	struct completion open_ack;
+	struct completion open_req;
+};
+
+#define to_glink_channel(_ept) container_of(_ept, struct glink_channel, ept)
+
+static const struct rpmsg_endpoint_ops glink_endpoint_ops;
+
+#define RPM_CMD_VERSION			0
+#define RPM_CMD_VERSION_ACK		1
+#define RPM_CMD_OPEN			2
+#define RPM_CMD_CLOSE			3
+#define RPM_CMD_OPEN_ACK		4
+#define RPM_CMD_TX_DATA			9
+#define RPM_CMD_CLOSE_ACK		11
+#define RPM_CMD_TX_DATA_CONT		12
+#define RPM_CMD_READ_NOTIF		13
+
+#define GLINK_FEATURE_INTENTLESS	BIT(1)
+
+static struct glink_channel *qcom_glink_alloc_channel(struct qcom_glink *glink,
+						      const char *name)
+{
+	struct glink_channel *channel;
+
+	channel = kzalloc(sizeof(*channel), GFP_KERNEL);
+	if (!channel)
+		return ERR_PTR(-ENOMEM);
+
+	/* Setup glink internal glink_channel data */
+	spin_lock_init(&channel->recv_lock);
+	channel->glink = glink;
+	channel->name = kstrdup(name, GFP_KERNEL);
+
+	init_completion(&channel->open_req);
+	init_completion(&channel->open_ack);
+
+	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);
+
+	kfree(channel->name);
+	kfree(channel);
+}
+
+static size_t qcom_glink_rx_avail(struct qcom_glink *glink)
+{
+	return glink->rx_pipe->avail(glink->rx_pipe);
+}
+
+static void qcom_glink_rx_peak(struct qcom_glink *glink,
+			       void *data, size_t count)
+{
+	glink->rx_pipe->peak(glink->rx_pipe, data, 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 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;
+	int ret;
+
+	/* Reject packets that are too big */
+	if (tlen >= glink->tx_pipe->length)
+		return -EINVAL;
+
+	if (WARN(tlen % 8, "Unaligned TX request"))
+		return -EINVAL;
+
+	ret = mutex_lock_interruptible(&glink->tx_lock);
+	if (ret)
+		return ret;
+
+	while (qcom_glink_tx_avail(glink) < tlen) {
+		if (!wait) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		usleep_range(10000, 15000);
+	}
+
+	qcom_glink_tx_write(glink, hdr, hlen, data, dlen);
+
+	mbox_send_message(glink->mbox_chan, NULL);
+	mbox_client_txdone(glink->mbox_chan, 0);
+
+out:
+	mutex_unlock(&glink->tx_lock);
+
+	return ret;
+}
+
+static int qcom_glink_send_version(struct qcom_glink *glink)
+{
+	struct glink_msg msg;
+
+	msg.cmd = cpu_to_le16(RPM_CMD_VERSION);
+	msg.param1 = cpu_to_le16(1);
+	msg.param2 = cpu_to_le32(GLINK_FEATURE_INTENTLESS);
+
+	return qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
+}
+
+static void qcom_glink_send_version_ack(struct qcom_glink *glink)
+{
+	struct glink_msg msg;
+
+	msg.cmd = cpu_to_le16(RPM_CMD_VERSION_ACK);
+	msg.param1 = cpu_to_le16(1);
+	msg.param2 = cpu_to_le32(0);
+
+	qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
+}
+
+static void qcom_glink_send_open_ack(struct qcom_glink *glink,
+				     struct glink_channel *channel)
+{
+	struct glink_msg msg;
+
+	msg.cmd = cpu_to_le16(RPM_CMD_OPEN_ACK);
+	msg.param1 = cpu_to_le16(channel->rcid);
+	msg.param2 = cpu_to_le32(0);
+
+	qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
+}
+
+/**
+ * qcom_glink_send_open_req() - send a RPM_CMD_OPEN request to the remote
+ * @glink: Ptr to the glink edge
+ * @channel: Ptr to the channel that the open req is sent
+ *
+ * Allocates a local channel id and sends a RPM_CMD_OPEN message to the remote.
+ * Will return with refcount held, regardless of outcome.
+ *
+ * Returns 0 on success, negative errno otherwise.
+ */
+static int qcom_glink_send_open_req(struct qcom_glink *glink,
+				    struct glink_channel *channel)
+{
+	struct {
+		struct glink_msg msg;
+		u8 name[GLINK_NAME_SIZE];
+	} __packed req;
+	int name_len = strlen(channel->name) + 1;
+	int req_len = ALIGN(sizeof(req.msg) + name_len, 8);
+	int ret;
+
+	kref_get(&channel->refcount);
+
+	mutex_lock(&glink->idr_lock);
+	ret = idr_alloc_cyclic(&glink->lcids, channel,
+			       RPM_GLINK_CID_MIN, RPM_GLINK_CID_MAX,
+			       GFP_KERNEL);
+	mutex_unlock(&glink->idr_lock);
+	if (ret < 0)
+		return ret;
+
+	channel->lcid = ret;
+
+	req.msg.cmd = cpu_to_le16(RPM_CMD_OPEN);
+	req.msg.param1 = cpu_to_le16(channel->lcid);
+	req.msg.param2 = cpu_to_le32(name_len);
+	strcpy(req.name, channel->name);
+
+	ret = qcom_glink_tx(glink, &req, req_len, NULL, 0, true);
+	if (ret)
+		goto remove_idr;
+
+	return 0;
+
+remove_idr:
+	mutex_lock(&glink->idr_lock);
+	idr_remove(&glink->lcids, channel->lcid);
+	channel->lcid = 0;
+	mutex_unlock(&glink->idr_lock);
+
+	return ret;
+}
+
+static void qcom_glink_send_close_req(struct qcom_glink *glink,
+				      struct glink_channel *channel)
+{
+	struct glink_msg req;
+
+	req.cmd = cpu_to_le16(RPM_CMD_CLOSE);
+	req.param1 = cpu_to_le16(channel->lcid);
+	req.param2 = 0;
+
+	qcom_glink_tx(glink, &req, sizeof(req), NULL, 0, true);
+}
+
+static void qcom_glink_send_close_ack(struct qcom_glink *glink,
+				      unsigned int rcid)
+{
+	struct glink_msg req;
+
+	req.cmd = cpu_to_le16(RPM_CMD_CLOSE_ACK);
+	req.param1 = cpu_to_le16(rcid);
+	req.param2 = 0;
+
+	qcom_glink_tx(glink, &req, sizeof(req), NULL, 0, true);
+}
+
+static 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(sizeof(*dcmd) + extra, GFP_ATOMIC);
+	if (!dcmd)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&dcmd->node);
+
+	qcom_glink_rx_peak(glink, &dcmd->msg, 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_channel *channel;
+	struct {
+		struct glink_msg msg;
+		__le32 chunk_size;
+		__le32 left_size;
+	} __packed hdr;
+	unsigned int chunk_size;
+	unsigned int left_size;
+	unsigned int rcid;
+
+	if (avail < sizeof(hdr)) {
+		dev_dbg(glink->dev, "Not enough data in fifo\n");
+		return -EAGAIN;
+	}
+
+	qcom_glink_rx_peak(glink, &hdr, 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;
+	}
+
+	if (WARN(chunk_size % 4, "Incoming data must be word aligned\n"))
+		return -EINVAL;
+
+	rcid = le16_to_cpu(hdr.msg.param1);
+	channel = idr_find(&glink->rcids, rcid);
+	if (!channel) {
+		dev_dbg(glink->dev, "Data on non-existing channel\n");
+
+		/* Drop the message */
+		qcom_glink_rx_advance(glink,
+				      ALIGN(sizeof(hdr) + chunk_size, 8));
+		return 0;
+	}
+
+	/* Might have an ongoing, fragmented, message to append */
+	if (!channel->buf) {
+		channel->buf = kmalloc(chunk_size + left_size, GFP_ATOMIC);
+		if (!channel->buf)
+			return -ENOMEM;
+
+		channel->buf_size = chunk_size + left_size;
+		channel->buf_offset = 0;
+	}
+
+	qcom_glink_rx_advance(glink, sizeof(hdr));
+
+	if (channel->buf_size - channel->buf_offset < chunk_size) {
+		dev_err(glink->dev, "Insufficient space in input buffer\n");
+
+		/* The packet header lied, drop payload */
+		qcom_glink_rx_advance(glink, chunk_size);
+		return -ENOMEM;
+	}
+
+	qcom_glink_rx_peak(glink, channel->buf + channel->buf_offset,
+			   chunk_size);
+	channel->buf_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,
+					channel->buf,
+					channel->buf_offset,
+					channel->ept.priv,
+					RPMSG_ADDR_ANY);
+		}
+		spin_unlock(&channel->recv_lock);
+
+		kfree(channel->buf);
+		channel->buf = NULL;
+		channel->buf_size = 0;
+	}
+
+	/* Each message starts at 8 byte aligned address */
+	qcom_glink_rx_advance(glink, ALIGN(chunk_size, 8));
+
+	return 0;
+}
+
+static int qcom_glink_rx_open_ack(struct qcom_glink *glink, unsigned int lcid)
+{
+	struct glink_channel *channel;
+
+	channel = idr_find(&glink->lcids, lcid);
+	if (!channel) {
+		dev_err(glink->dev, "Invalid open ack packet\n");
+		return -EINVAL;
+	}
+
+	complete(&channel->open_ack);
+
+	return 0;
+}
+
+static irqreturn_t qcom_glink_native_intr(int irq, void *data)
+{
+	struct qcom_glink *glink = data;
+	struct glink_msg msg;
+	unsigned int param1;
+	unsigned int param2;
+	unsigned int avail;
+	unsigned int cmd;
+	int ret;
+
+	for (;;) {
+		avail = qcom_glink_rx_avail(glink);
+		if (avail < sizeof(msg))
+			break;
+
+		qcom_glink_rx_peak(glink, &msg, sizeof(msg));
+
+		cmd = le16_to_cpu(msg.cmd);
+		param1 = le16_to_cpu(msg.param1);
+		param2 = le32_to_cpu(msg.param2);
+
+		switch (cmd) {
+		case RPM_CMD_VERSION:
+		case RPM_CMD_VERSION_ACK:
+		case RPM_CMD_CLOSE:
+		case RPM_CMD_CLOSE_ACK:
+			ret = qcom_glink_rx_defer(glink, 0);
+			break;
+		case RPM_CMD_OPEN_ACK:
+			ret = qcom_glink_rx_open_ack(glink, param1);
+			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
+			break;
+		case RPM_CMD_OPEN:
+			ret = qcom_glink_rx_defer(glink, param2);
+			break;
+		case RPM_CMD_TX_DATA:
+		case RPM_CMD_TX_DATA_CONT:
+			ret = qcom_glink_rx_data(glink, avail);
+			break;
+		case RPM_CMD_READ_NOTIF:
+			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
+
+			mbox_send_message(glink->mbox_chan, NULL);
+			mbox_client_txdone(glink->mbox_chan, 0);
+
+			ret = 0;
+			break;
+		default:
+			dev_err(glink->dev, "unhandled rx cmd: %d\n", cmd);
+			ret = -EINVAL;
+			break;
+		}
+
+		if (ret)
+			break;
+	}
+
+	return IRQ_HANDLED;
+}
+
+/* Locally initiated rpmsg_create_ept */
+static struct glink_channel *qcom_glink_create_local(struct qcom_glink *glink,
+						     const char *name)
+{
+	struct glink_channel *channel;
+	int ret;
+
+	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*/
+	mutex_lock(&glink->idr_lock);
+	idr_remove(&glink->lcids, channel->lcid);
+	mutex_unlock(&glink->idr_lock);
+
+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 the last reference.
+	 */
+	qcom_glink_send_close_req(glink, channel);
+
+	/* Release qcom_glink_send_open_req() reference */
+	kref_put(&channel->refcount, qcom_glink_channel_release);
+
+	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;
+
+	idr_for_each_entry(&glink->rcids, channel, cid) {
+		if (!strcmp(channel->name, name))
+			break;
+	}
+
+	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 void qcom_glink_destroy_ept(struct rpmsg_endpoint *ept)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+	struct qcom_glink *glink = channel->glink;
+	unsigned long flags;
+
+	spin_lock_irqsave(&channel->recv_lock, flags);
+	channel->ept.cb = NULL;
+	spin_unlock_irqrestore(&channel->recv_lock, flags);
+
+	/* Decouple the potential rpdev from the channel */
+	channel->rpdev = NULL;
+
+	qcom_glink_send_close_req(glink, channel);
+}
+
+static int __qcom_glink_send(struct glink_channel *channel,
+			     void *data, int len, bool wait)
+{
+	struct qcom_glink *glink = channel->glink;
+	struct {
+		struct glink_msg msg;
+		__le32 chunk_size;
+		__le32 left_size;
+	} __packed req;
+
+	if (WARN(len % 8, "RPM GLINK expects 8 byte aligned messages\n"))
+		return -EINVAL;
+
+	req.msg.cmd = cpu_to_le16(RPM_CMD_TX_DATA);
+	req.msg.param1 = cpu_to_le16(channel->lcid);
+	req.msg.param2 = cpu_to_le32(channel->rcid);
+	req.chunk_size = cpu_to_le32(len);
+	req.left_size = cpu_to_le32(0);
+
+	return qcom_glink_tx(glink, &req, sizeof(req), data, len, wait);
+}
+
+static int qcom_glink_send(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+
+	return __qcom_glink_send(channel, data, len, true);
+}
+
+static int qcom_glink_trysend(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+
+	return __qcom_glink_send(channel, data, len, false);
+}
+
+/*
+ * 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,
+};
+
+static const struct rpmsg_endpoint_ops glink_endpoint_ops = {
+	.destroy_ept = qcom_glink_destroy_ept,
+	.send = qcom_glink_send,
+	.trysend = qcom_glink_trysend,
+};
+
+static void qcom_glink_rpdev_release(struct device *dev)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+	struct glink_channel *channel = to_glink_channel(rpdev->ept);
+
+	channel->rpdev = NULL;
+	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;
+
+	idr_for_each_entry(&glink->lcids, channel, lcid) {
+		if (!strcmp(channel->name, name))
+			break;
+	}
+
+	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;
+	}
+
+	mutex_lock(&glink->idr_lock);
+	ret = idr_alloc(&glink->rcids, channel, rcid, rcid + 1, GFP_KERNEL);
+	if (ret < 0) {
+		dev_err(glink->dev, "Unable to insert channel into rcid list\n");
+		mutex_unlock(&glink->idr_lock);
+		goto free_channel;
+	}
+	channel->rcid = ret;
+	mutex_unlock(&glink->idr_lock);
+
+	complete(&channel->open_req);
+
+	if (create_device) {
+		rpdev = kzalloc(sizeof(*rpdev), GFP_KERNEL);
+		if (!rpdev) {
+			ret = -ENOMEM;
+			goto rcid_remove;
+		}
+
+		rpdev->ept = &channel->ept;
+		strncpy(rpdev->id.name, name, RPMSG_NAME_SIZE);
+		rpdev->src = RPMSG_ADDR_ANY;
+		rpdev->dst = RPMSG_ADDR_ANY;
+		rpdev->ops = &glink_device_ops;
+
+		node = qcom_glink_match_channel(glink->dev->of_node, name);
+		rpdev->dev.of_node = node;
+		rpdev->dev.parent = glink->dev;
+		rpdev->dev.release = qcom_glink_rpdev_release;
+
+		ret = rpmsg_register_device(rpdev);
+		if (ret)
+			goto free_rpdev;
+
+		channel->rpdev = rpdev;
+	}
+
+	return 0;
+
+free_rpdev:
+	kfree(rpdev);
+rcid_remove:
+	mutex_lock(&glink->idr_lock);
+	idr_remove(&glink->rcids, channel->rcid);
+	channel->rcid = 0;
+	mutex_unlock(&glink->idr_lock);
+free_channel:
+	/* Release the reference, iff we took it */
+	if (create_device)
+		kref_put(&channel->refcount, qcom_glink_channel_release);
+
+	return ret;
+}
+
+static void qcom_glink_rx_close(struct qcom_glink *glink, unsigned int rcid)
+{
+	struct rpmsg_channel_info chinfo;
+	struct glink_channel *channel;
+
+	channel = idr_find(&glink->rcids, rcid);
+	if (WARN(!channel, "close request on unknown channel\n"))
+		return;
+
+	if (channel->rpdev) {
+		strncpy(chinfo.name, channel->name, sizeof(chinfo.name));
+		chinfo.src = RPMSG_ADDR_ANY;
+		chinfo.dst = RPMSG_ADDR_ANY;
+
+		rpmsg_unregister_device(glink->dev, &chinfo);
+	}
+
+	qcom_glink_send_close_ack(glink, channel->rcid);
+
+	mutex_lock(&glink->idr_lock);
+	idr_remove(&glink->rcids, channel->rcid);
+	channel->rcid = 0;
+	mutex_unlock(&glink->idr_lock);
+
+	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;
+
+	channel = idr_find(&glink->lcids, lcid);
+	if (WARN(!channel, "close ack on unknown channel\n"))
+		return;
+
+	mutex_lock(&glink->idr_lock);
+	idr_remove(&glink->lcids, channel->lcid);
+	channel->lcid = 0;
+	mutex_unlock(&glink->idr_lock);
+
+	kref_put(&channel->refcount, qcom_glink_channel_release);
+}
+
+static void qcom_glink_work(struct work_struct *work)
+{
+	struct qcom_glink *glink = container_of(work, struct qcom_glink,
+						rx_work);
+	struct glink_defer_cmd *dcmd;
+	struct glink_msg *msg;
+	unsigned long flags;
+	unsigned int param1;
+	unsigned int param2;
+	unsigned int cmd;
+
+	for (;;) {
+		spin_lock_irqsave(&glink->rx_lock, flags);
+		if (list_empty(&glink->rx_queue)) {
+			spin_unlock_irqrestore(&glink->rx_lock, flags);
+			break;
+		}
+		dcmd = list_first_entry(&glink->rx_queue,
+					struct glink_defer_cmd, node);
+		list_del(&dcmd->node);
+		spin_unlock_irqrestore(&glink->rx_lock, flags);
+
+		msg = &dcmd->msg;
+		cmd = le16_to_cpu(msg->cmd);
+		param1 = le16_to_cpu(msg->param1);
+		param2 = le32_to_cpu(msg->param2);
+
+		switch (cmd) {
+		case RPM_CMD_VERSION:
+			qcom_glink_send_version_ack(glink);
+			break;
+		case RPM_CMD_VERSION_ACK:
+			break;
+		case RPM_CMD_OPEN:
+			qcom_glink_rx_open(glink, param1, msg->data);
+			break;
+		case RPM_CMD_CLOSE:
+			qcom_glink_rx_close(glink, param1);
+			break;
+		case RPM_CMD_CLOSE_ACK:
+			qcom_glink_rx_close_ack(glink, param1);
+			break;
+		default:
+			WARN(1, "Unknown defer object %d\n", cmd);
+			break;
+		}
+
+		kfree(dcmd);
+	}
+}
+
+struct qcom_glink *qcom_glink_native_probe(struct device *dev,
+					   struct qcom_glink_pipe *rx,
+					   struct qcom_glink_pipe *tx)
+{
+	int irq;
+	int ret;
+	struct qcom_glink *glink;
+
+	glink = devm_kzalloc(dev, sizeof(*glink), GFP_KERNEL);
+	if (!glink)
+		return ERR_PTR(-ENOMEM);
+
+	glink->dev = dev;
+	glink->tx_pipe = tx;
+	glink->rx_pipe = rx;
+
+	mutex_init(&glink->tx_lock);
+	spin_lock_init(&glink->rx_lock);
+	INIT_LIST_HEAD(&glink->rx_queue);
+	INIT_WORK(&glink->rx_work, qcom_glink_work);
+
+	mutex_init(&glink->idr_lock);
+	idr_init(&glink->lcids);
+	idr_init(&glink->rcids);
+
+	glink->mbox_client.dev = dev;
+	glink->mbox_chan = mbox_request_channel(&glink->mbox_client, 0);
+	if (IS_ERR(glink->mbox_chan)) {
+		if (PTR_ERR(glink->mbox_chan) != -EPROBE_DEFER)
+			dev_err(dev, "failed to acquire IPC channel\n");
+		return ERR_CAST(glink->mbox_chan);
+	}
+
+	irq = of_irq_get(dev->of_node, 0);
+	ret = devm_request_irq(dev, irq,
+			       qcom_glink_native_intr,
+			       IRQF_NO_SUSPEND | IRQF_SHARED,
+			       "glink-native", glink);
+	if (ret) {
+		dev_err(dev, "failed to request IRQ\n");
+		return ERR_PTR(ret);
+	}
+
+	glink->irq = irq;
+
+	ret = qcom_glink_send_version(glink);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return glink;
+}
+
+static int qcom_glink_remove_device(struct device *dev, void *data)
+{
+	device_unregister(dev);
+
+	return 0;
+}
+
+void qcom_glink_native_remove(struct qcom_glink *glink)
+{
+	struct glink_channel *channel;
+	int cid;
+	int ret;
+
+	disable_irq(glink->irq);
+	cancel_work_sync(&glink->rx_work);
+
+	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);
+
+	idr_destroy(&glink->lcids);
+	idr_destroy(&glink->rcids);
+}