Merge tag 'rpmsg-v4.9' of git://github.com/andersson/remoteproc

Pull rpmsg updates from Bjorn Andersson:
"The bulk of these patches involve splitting the rpmsg implementation
into a framework/API part and a virtio specific backend part. It then
adds the Qualcomm Shared Memory Device (SMD) as an additional
supported wire format.

Also included is a set of code style cleanups that have been lingering
for a while"

* tag 'rpmsg-v4.9' of git://github.com/andersson/remoteproc: (26 commits)
rpmsg: smd: fix dependency on QCOM_SMD=n
rpmsg: Introduce Qualcomm SMD backend
rpmsg: Allow callback to return errors
rpmsg: Move virtio specifics from public header
rpmsg: virtio: Hide vrp pointer from the public API
rpmsg: Hide rpmsg indirection tables
rpmsg: Split rpmsg core and virtio backend
rpmsg: Split off generic tail of create_channel()
rpmsg: Move helper for finding rpmsg devices to core
rpmsg: Move endpoint related interface to rpmsg core
rpmsg: Indirection table for rpmsg_endpoint operations
rpmsg: Move rpmsg_device API to new file
rpmsg: Introduce indirection table for rpmsg_device operations
rpmsg: Clean up rpmsg device vs channel naming
rpmsg: Make rpmsg_create_ept() take channel_info struct
rpmsg: rpmsg_send() operations takes rpmsg_endpoint
rpmsg: Name rpmsg devices based on channel id
rpmsg: Enable matching devices with drivers based on DT
rpmsg: Drop prototypes for non-existing functions
samples/rpmsg: add support for multiple instances
...

drivers/remoteproc/Kconfig

···
 	select REMOTEPROC
 	select MAILBOX
 	select OMAP2PLUS_MBOX
-	select RPMSG
+	select RPMSG_VIRTIO
 	help
 	  Say y here to support OMAP's remote processors (dual M3
 	  and DSP on OMAP4) via the remote processor framework.
···
 	depends on ARCH_DAVINCI_DA8XX
 	select CMA if MMU
 	select REMOTEPROC
-	select RPMSG
+	select RPMSG_VIRTIO
 	help
 	  Say y here to support DA8xx/OMAP-L13x remote processors via the
 	  remote processor framework.

drivers/rpmsg/Kconfig

···
 # RPMSG always gets selected by whoever wants it
 config RPMSG
 	tristate
+
+config RPMSG_QCOM_SMD
+	tristate "Qualcomm Shared Memory Driver (SMD)"
+	depends on QCOM_SMEM
+	depends on QCOM_SMD=n
+	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
+	select RPMSG
 	select VIRTIO
 	select VIRTUALIZATION
 

drivers/rpmsg/Makefile

···
-obj-$(CONFIG_RPMSG)	+= virtio_rpmsg_bus.o
+obj-$(CONFIG_RPMSG)		+= rpmsg_core.o
+obj-$(CONFIG_RPMSG_QCOM_SMD)	+= qcom_smd.o
+obj-$(CONFIG_RPMSG_VIRTIO)	+= virtio_rpmsg_bus.o

drivers/rpmsg/qcom_smd.c

···
+/*
+ * Copyright (c) 2015, Sony Mobile Communications AB.
+ * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
+ *
+ * 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/interrupt.h>
+#include <linux/io.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/slab.h>
+#include <linux/soc/qcom/smem.h>
+#include <linux/wait.h>
+#include <linux/rpmsg.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
+ * @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
+ * @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
+ * @scan_work:		work item for discovering new channels
+ * @state_work:		work item for edge state changes
+ */
+struct qcom_smd_edge {
+	struct device dev;
+
+	struct device_node *of_node;
+	unsigned edge_id;
+	unsigned remote_pid;
+
+	int irq;
+
+	struct regmap *ipc_regmap;
+	int ipc_offset;
+	int ipc_bit;
+
+	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(_rpdev)	container_of(_rpdev, struct qcom_smd_device, rpdev)
+#define to_smd_edge(d)		container_of(d, struct qcom_smd_edge, dev)
+#define to_smd_endpoint(ept)	container_of(ept, struct qcom_smd_endpoint, ept)
+
+/**
+ * struct qcom_smd_channel - smd channel struct
+ * @edge:		qcom_smd_edge this channel is living on
+ * @qsdev:		reference to a associated smd client device
+ * @name:		name of the channel
+ * @state:		local state of the channel
+ * @remote_state:	remote state of the channel
+ * @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
+ * @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;
+
+	struct smd_channel_info_pair *info;
+	struct smd_channel_info_word_pair *info_word;
+
+	struct mutex 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;
+
+	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;
+	}
+	/* 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(&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
+ *
+ * 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;
+	int ret;
+
+	/* Word aligned channels only accept word size aligned data */
+	if (channel->info_word && len % 4)
+		return -EINVAL;
+
+	/* Reject packets that are too big */
+	if (tlen >= channel->fifo_size)
+		return -EINVAL;
+
+	ret = mutex_lock_interruptible(&channel->tx_lock);
+	if (ret)
+		return ret;
+
+	while (qcom_smd_get_tx_avail(channel) < tlen) {
+		if (!wait) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		if (channel->state != SMD_CHANNEL_OPENED) {
+			ret = -EPIPE;
+			goto out;
+		}
+
+		SET_TX_CHANNEL_FLAG(channel, fBLOCKREADINTR, 0);
+
+		ret = wait_event_interruptible(channel->fblockread_event,
+				       qcom_smd_get_tx_avail(channel) >= tlen ||
+				       channel->state != SMD_CHANNEL_OPENED);
+		if (ret)
+			goto out;
+
+		SET_TX_CHANNEL_FLAG(channel, fBLOCKREADINTR, 1);
+	}
+
+	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:
+	mutex_unlock(&channel->tx_lock);
+
+	return ret;
+}
+
+/*
+ * Helper for opening a channel
+ */
+static int qcom_smd_channel_open(struct qcom_smd_channel *channel,
+				 rpmsg_rx_cb_t cb)
+{
+	size_t bb_size;
+
+	/*
+	 * 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);
+	qcom_smd_channel_set_state(channel, SMD_CHANNEL_OPENED);
+
+	return 0;
+}
+
+/*
+ * 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;
+	unsigned state;
+
+	spin_lock_irqsave(&edge->channels_lock, flags);
+	list_for_each_entry(channel, &edge->channels, list) {
+		if (strcmp(channel->name, name))
+			continue;
+
+		state = GET_RX_CHANNEL_INFO(channel, state);
+		if (state != SMD_CHANNEL_OPENING &&
+		    state != SMD_CHANNEL_OPENED)
+			continue;
+
+		ret = channel;
+		break;
+	}
+	spin_unlock_irqrestore(&edge->channels_lock, flags);
+
+	return ret;
+}
+
+static void __ept_release(struct kref *kref)
+{
+	struct rpmsg_endpoint *ept = container_of(kref, struct rpmsg_endpoint,
+						  refcount);
+	kfree(to_smd_endpoint(ept));
+}
+
+static struct rpmsg_endpoint *qcom_smd_create_ept(struct rpmsg_device *rpdev,
+						  rpmsg_rx_cb_t cb, void *priv,
+						  struct rpmsg_channel_info chinfo)
+{
+	struct qcom_smd_endpoint *qsept;
+	struct qcom_smd_channel *channel;
+	struct qcom_smd_device *qsdev = to_smd_device(rpdev);
+	struct qcom_smd_edge *edge = qsdev->edge;
+	struct rpmsg_endpoint *ept;
+	const char *name = chinfo.name;
+	int ret;
+
+	/* Wait up to HZ for the channel to appear */
+	ret = wait_event_interruptible_timeout(edge->new_channel_event,
+			(channel = qcom_smd_find_channel(edge, name)) != NULL,
+			HZ);
+	if (!ret)
+		return NULL;
+
+	if (channel->state != SMD_CHANNEL_CLOSED) {
+		dev_err(&rpdev->dev, "channel %s is busy\n", channel->name);
+		return NULL;
+	}
+
+	qsept = kzalloc(sizeof(*qsept), GFP_KERNEL);
+	if (!qsept)
+		return NULL;
+
+	ept = &qsept->ept;
+
+	kref_init(&ept->refcount);
+
+	ept->rpdev = rpdev;
+	ept->cb = cb;
+	ept->priv = priv;
+	ept->ops = &qcom_smd_endpoint_ops;
+
+	channel->qsept = qsept;
+	qsept->qsch = channel;
+
+	ret = qcom_smd_channel_open(channel, cb);
+	if (ret)
+		goto free_ept;
+
+	return ept;
+
+free_ept:
+	channel->qsept = NULL;
+	kref_put(&ept->refcount, __ept_release);
+	return NULL;
+}
+
+static void qcom_smd_destroy_ept(struct rpmsg_endpoint *ept)
+{
+	struct qcom_smd_endpoint *qsept = to_smd_endpoint(ept);
+	struct qcom_smd_channel *ch = qsept->qsch;
+
+	qcom_smd_channel_close(ch);
+	ch->qsept = NULL;
+	kref_put(&ept->refcount, __ept_release);
+}
+
+static int qcom_smd_send(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct qcom_smd_endpoint *qsept = to_smd_endpoint(ept);
+
+	return __qcom_smd_send(qsept->qsch, data, len, true);
+}
+
+static int qcom_smd_trysend(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct qcom_smd_endpoint *qsept = to_smd_endpoint(ept);
+
+	return __qcom_smd_send(qsept->qsch, data, len, false);
+}
+
+/*
+ * 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 const struct rpmsg_device_ops qcom_smd_device_ops = {
+	.create_ept = qcom_smd_create_ept,
+};
+
+static const struct rpmsg_endpoint_ops qcom_smd_endpoint_ops = {
+	.destroy_ept = qcom_smd_destroy_ept,
+	.send = qcom_smd_send,
+	.trysend = qcom_smd_trysend,
+};
+
+/*
+ * Create a smd client device for channel that is being opened.
+ */
+static int qcom_smd_create_device(struct qcom_smd_channel *channel)
+{
+	struct qcom_smd_device *qsdev;
+	struct rpmsg_device *rpdev;
+	struct qcom_smd_edge *edge = channel->edge;
+
+	dev_dbg(&edge->dev, "registering '%s'\n", channel->name);
+
+	qsdev = kzalloc(sizeof(*qsdev), GFP_KERNEL);
+	if (!qsdev)
+		return -ENOMEM;
+
+	/* Link qsdev to our SMD edge */
+	qsdev->edge = edge;
+
+	/* Assign callbacks for rpmsg_device */
+	qsdev->rpdev.ops = &qcom_smd_device_ops;
+
+	/* Assign public information to the rpmsg_device */
+	rpdev = &qsdev->rpdev;
+	strncpy(rpdev->id.name, channel->name, RPMSG_NAME_SIZE);
+	rpdev->src = RPMSG_ADDR_ANY;
+	rpdev->dst = RPMSG_ADDR_ANY;
+
+	rpdev->dev.of_node = qcom_smd_match_channel(edge->of_node, channel->name);
+	rpdev->dev.parent = &edge->dev;
+
+	return rpmsg_register_device(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 = devm_kzalloc(&edge->dev, sizeof(*channel), GFP_KERNEL);
+	if (!channel)
+		return ERR_PTR(-ENOMEM);
+
+	channel->edge = edge;
+	channel->name = devm_kstrdup(&edge->dev, name, GFP_KERNEL);
+	if (!channel->name)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&channel->tx_lock);
+	spin_lock_init(&channel->recv_lock);
+	init_waitqueue_head(&channel->fblockread_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:
+	devm_kfree(&edge->dev, channel->name);
+	devm_kfree(&edge->dev, 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(&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;
+
+		remote_state = GET_RX_CHANNEL_INFO(channel, state);
+		if (remote_state != SMD_CHANNEL_OPENING &&
+		    remote_state != SMD_CHANNEL_OPENED)
+			continue;
+
+		if (channel->registered)
+			continue;
+
+		spin_unlock_irqrestore(&edge->channels_lock, flags);
+		qcom_smd_create_device(channel);
+		channel->registered = true;
+		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);
+
+		strncpy(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);
+		return -EINVAL;
+	}
+
+	edge->remote_pid = QCOM_SMEM_HOST_ANY;
+	key = "qcom,remote-pid";
+	of_property_read_u32(node, key, &edge->remote_pid);
+
+	syscon_np = of_parse_phandle(node, "qcom,ipc", 0);
+	if (!syscon_np) {
+		dev_err(dev, "no qcom,ipc node\n");
+		return -ENODEV;
+	}
+
+	edge->ipc_regmap = syscon_node_to_regmap(syscon_np);
+	if (IS_ERR(edge->ipc_regmap))
+		return PTR_ERR(edge->ipc_regmap);
+
+	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);
+		return -EINVAL;
+	}
+
+	ret = of_property_read_u32_index(node, key, 2, &edge->ipc_bit);
+	if (ret < 0) {
+		dev_err(dev, "no bit in %s\n", key);
+		return -EINVAL;
+	}
+
+	irq = irq_of_parse_and_map(node, 0);
+	if (irq < 0) {
+		dev_err(dev, "required smd interrupt missing\n");
+		return -EINVAL;
+	}
+
+	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");
+		return ret;
+	}
+
+	edge->irq = irq;
+
+	return 0;
+}
+
+/*
+ * 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;
+	struct qcom_smd_edge *edge = to_smd_edge(dev);
+
+	list_for_each_entry(channel, &edge->channels, list) {
+		SET_RX_CHANNEL_INFO(channel, state, SMD_CHANNEL_CLOSED);
+		SET_RX_CHANNEL_INFO(channel, head, 0);
+		SET_RX_CHANNEL_INFO(channel, tail, 0);
+	}
+
+	kfree(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
+ *
+ * Returns an edge reference, or negative ERR_PTR() on failure.
+ */
+struct qcom_smd_edge *qcom_smd_register_edge(struct device *parent,
+					     struct device_node *node)
+{
+	struct qcom_smd_edge *edge;
+	int ret;
+
+	edge = kzalloc(sizeof(*edge), GFP_KERNEL);
+	if (!edge)
+		return ERR_PTR(-ENOMEM);
+
+	init_waitqueue_head(&edge->new_channel_event);
+
+	edge->dev.parent = parent;
+	edge->dev.release = qcom_smd_edge_release;
+	dev_set_name(&edge->dev, "%s:%s", dev_name(parent), node->name);
+	ret = device_register(&edge->dev);
+	if (ret) {
+		pr_err("failed to register smd edge\n");
+		return ERR_PTR(ret);
+	}
+
+	ret = qcom_smd_parse_edge(&edge->dev, node, edge);
+	if (ret) {
+		dev_err(&edge->dev, "failed to parse smd edge\n");
+		goto unregister_dev;
+	}
+
+	schedule_work(&edge->scan_work);
+
+	return edge;
+
+unregister_dev:
+	put_device(&edge->dev);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(qcom_smd_register_edge);
+
+static int qcom_smd_remove_device(struct device *dev, void *data)
+{
+	device_unregister(dev);
+
+	return 0;
+}
+
+/**
+ * qcom_smd_unregister_edge() - release an edge and its children
+ * @edge:      edge reference acquired from qcom_smd_register_edge
+ */
+int qcom_smd_unregister_edge(struct qcom_smd_edge *edge)
+{
+	int ret;
+
+	disable_irq(edge->irq);
+	cancel_work_sync(&edge->scan_work);
+	cancel_work_sync(&edge->state_work);
+
+	ret = device_for_each_child(&edge->dev, NULL, qcom_smd_remove_device);
+	if (ret)
+		dev_warn(&edge->dev, "can't remove smd device: %d\n", ret);
+
+	device_unregister(&edge->dev);
+
+	return 0;
+}
+EXPORT_SYMBOL(qcom_smd_unregister_edge);
+
+static int qcom_smd_probe(struct platform_device *pdev)
+{
+	struct device_node *node;
+	void *p;
+
+	/* Wait for smem */
+	p = qcom_smem_get(QCOM_SMEM_HOST_ANY, smem_items[0].alloc_tbl_id, NULL);
+	if (PTR_ERR(p) == -EPROBE_DEFER)
+		return PTR_ERR(p);
+
+	for_each_available_child_of_node(pdev->dev.of_node, node)
+		qcom_smd_register_edge(&pdev->dev, node);
+
+	return 0;
+}
+
+static int qcom_smd_remove_edge(struct device *dev, void *data)
+{
+	struct qcom_smd_edge *edge = to_smd_edge(dev);
+
+	return qcom_smd_unregister_edge(edge);
+}
+
+/*
+ * Shut down all smd clients by making sure that each edge stops processing
+ * events and scanning for new channels, then call destroy on the devices.
+ */
+static int qcom_smd_remove(struct platform_device *pdev)
+{
+	int ret;
+
+	ret = device_for_each_child(&pdev->dev, NULL, qcom_smd_remove_edge);
+	if (ret)
+		dev_warn(&pdev->dev, "can't remove smd device: %d\n", ret);
+
+	return ret;
+}
+
+static const struct of_device_id qcom_smd_of_match[] = {
+	{ .compatible = "qcom,smd" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, qcom_smd_of_match);
+
+static struct platform_driver qcom_smd_driver = {
+	.probe = qcom_smd_probe,
+	.remove = qcom_smd_remove,
+	.driver = {
+		.name = "qcom-smd",
+		.of_match_table = qcom_smd_of_match,
+	},
+};
+
+static int __init qcom_smd_init(void)
+{
+	return platform_driver_register(&qcom_smd_driver);
+}
+subsys_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 <[e-mail]>");
+MODULE_DESCRIPTION("Qualcomm Shared Memory Driver");
+MODULE_LICENSE("GPL v2");

drivers/rpmsg/rpmsg_core.c

···
+/*
+ * remote processor messaging bus
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Ohad Ben-Cohen <[e-mail]>
+ * Brian Swetland <[e-mail]>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+
+#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/slab.h>
+
+#include "rpmsg_internal.h"
+
+/**
+ * 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 do 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).
+ *
+ * Returns 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)
+{
+	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().
+ */
+void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
+{
+	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).
+ *
+ * Returns 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	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).
+ *
+ * Returns 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
+{
+	return ept->ops->sendto(ept, data, len, dst);
+}
+EXPORT_SYMBOL(rpmsg_sendto);
+
+/**
+ * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
+ * @ept: the rpmsg endpoint
+ * @src: source address
+ * @dst: destination address
+ * @data: payload of message
+ * @len: length of payload
+ *
+ * This function sends @data of length @len to the remote @dst address,
+ * and uses @src as the source address.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to.
+ * In case there are no TX buffers available, the function will block until
+ * one becomes available, or a timeout of 15 seconds elapses. When the latter
+ * happens, -ERESTARTSYS is returned.
+ *
+ * Can only be called from process context (for now).
+ *
+ * Returns 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+			  void *data, int len)
+{
+	return ept->ops->send_offchannel(ept, src, dst, data, len);
+}
+EXPORT_SYMBOL(rpmsg_send_offchannel);
+
+/**
+ * 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 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).
+ *
+ * Returns 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	return ept->ops->trysend(ept, data, len);
+}
+EXPORT_SYMBOL(rpmsg_trysend);
+
+/**
+ * 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 immediately
+ * return -ENOMEM without waiting until one becomes available.
+ *
+ * Can only be called from process context (for now).
+ *
+ * Returns 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
+{
+	return ept->ops->trysendto(ept, data, len, dst);
+}
+EXPORT_SYMBOL(rpmsg_trysendto);
+
+/**
+ * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
+ * @ept: the rpmsg endpoint
+ * @src: source address
+ * @dst: destination address
+ * @data: payload of message
+ * @len: length of payload
+ *
+ * This function sends @data of length @len to the remote @dst address,
+ * and uses @src as the source address.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to.
+ * In case there are no TX buffers available, the function will immediately
+ * return -ENOMEM without waiting until one becomes available.
+ *
+ * Can only be called from process context (for now).
+ *
+ * Returns 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+			     void *data, int len)
+{
+	return ept->ops->trysend_offchannel(ept, src, dst, data, len);
+}
+EXPORT_SYMBOL(rpmsg_trysend_offchannel);
+
+/*
+ * match an rpmsg channel with a channel info struct.
+ * this is used to make sure we're not creating rpmsg devices for channels
+ * that already exist.
+ */
+static int rpmsg_device_match(struct device *dev, void *data)
+{
+	struct rpmsg_channel_info *chinfo = data;
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+
+	if (chinfo->src != RPMSG_ADDR_ANY && chinfo->src != rpdev->src)
+		return 0;
+
+	if (chinfo->dst != RPMSG_ADDR_ANY && chinfo->dst != rpdev->dst)
+		return 0;
+
+	if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE))
+		return 0;
+
+	/* found a match ! */
+	return 1;
+}
+
+struct device *rpmsg_find_device(struct device *parent,
+				 struct rpmsg_channel_info *chinfo)
+{
+	return device_find_child(parent, chinfo, rpmsg_device_match);
+
+}
+EXPORT_SYMBOL(rpmsg_find_device);
+
+/* sysfs show configuration fields */
+#define rpmsg_show_attr(field, path, format_string)			\
+static ssize_t								\
+field##_show(struct device *dev,					\
+			struct device_attribute *attr, char *buf)	\
+{									\
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);		\
+									\
+	return sprintf(buf, format_string, rpdev->path);		\
+}
+
+/* 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);
+
+	return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name);
+}
+
+static struct device_attribute rpmsg_dev_attrs[] = {
+	__ATTR_RO(name),
+	__ATTR_RO(modalias),
+	__ATTR_RO(dst),
+	__ATTR_RO(src),
+	__ATTR_RO(announce),
+	__ATTR_NULL
+};
+
+/* rpmsg devices and drivers are matched using the service name */
+static inline int rpmsg_id_match(const struct rpmsg_device *rpdev,
+				  const struct rpmsg_device_id *id)
+{
+	return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0;
+}
+
+/* match rpmsg channel and rpmsg driver */
+static int rpmsg_dev_match(struct device *dev, struct device_driver *drv)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+	struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
+	const struct rpmsg_device_id *ids = rpdrv->id_table;
+	unsigned int i;
+
+	if (ids)
+		for (i = 0; ids[i].name[0]; i++)
+			if (rpmsg_id_match(rpdev, &ids[i]))
+				return 1;
+
+	return of_driver_match_device(dev, drv);
+}
+
+static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+
+	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;
+	int err;
+
+	strncpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
+	chinfo.src = rpdev->src;
+	chinfo.dst = RPMSG_ADDR_ANY;
+
+	ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, chinfo);
+	if (!ept) {
+		dev_err(dev, "failed to create endpoint\n");
+		err = -ENOMEM;
+		goto out;
+	}
+
+	rpdev->ept = ept;
+	rpdev->src = ept->addr;
+
+	err = rpdrv->probe(rpdev);
+	if (err) {
+		dev_err(dev, "%s: failed: %d\n", __func__, err);
+		rpmsg_destroy_ept(ept);
+		goto out;
+	}
+
+	if (rpdev->ops->announce_create)
+		err = rpdev->ops->announce_create(rpdev);
+out:
+	return err;
+}
+
+static int rpmsg_dev_remove(struct device *dev)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+	struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
+	int err = 0;
+
+	if (rpdev->ops->announce_destroy)
+		err = rpdev->ops->announce_destroy(rpdev);
+
+	rpdrv->remove(rpdev);
+
+	rpmsg_destroy_ept(rpdev->ept);
+
+	return err;
+}
+
+static struct bus_type rpmsg_bus = {
+	.name		= "rpmsg",
+	.match		= rpmsg_dev_match,
+	.dev_attrs	= rpmsg_dev_attrs,
+	.uevent		= rpmsg_uevent,
+	.probe		= rpmsg_dev_probe,
+	.remove		= rpmsg_dev_remove,
+};
+
+static void rpmsg_release_device(struct device *dev)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+
+	kfree(rpdev);
+}
+
+int rpmsg_register_device(struct rpmsg_device *rpdev)
+{
+	struct device *dev = &rpdev->dev;
+	int ret;
+
+	dev_set_name(&rpdev->dev, "%s:%s",
+		     dev_name(dev->parent), rpdev->id.name);
+
+	rpdev->dev.bus = &rpmsg_bus;
+	rpdev->dev.release = rpmsg_release_device;
+
+	ret = device_register(&rpdev->dev);
+	if (ret) {
+		dev_err(dev, "device_register failed: %d\n", ret);
+		put_device(&rpdev->dev);
+	}
+
+	return ret;
+}
+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
+ *
+ * Returns 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
+ *
+ * Returns 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 = bus_register(&rpmsg_bus);
+	if (ret)
+		pr_err("failed to register rpmsg bus: %d\n", ret);
+
+	return ret;
+}
+postcore_initcall(rpmsg_init);
+
+static void __exit rpmsg_fini(void)
+{
+	bus_unregister(&rpmsg_bus);
+}
+module_exit(rpmsg_fini);
+
+MODULE_DESCRIPTION("remote processor messaging bus");
+MODULE_LICENSE("GPL v2");

drivers/rpmsg/rpmsg_internal.h

···
+/*
+ * remote processor messaging bus internals
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Ohad Ben-Cohen <[e-mail]>
+ * Brian Swetland <[e-mail]>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+
+#ifndef __RPMSG_INTERNAL_H__
+#define __RPMSG_INTERNAL_H__
+
+#include <linux/rpmsg.h>
+
+#define to_rpmsg_device(d) container_of(d, struct rpmsg_device, dev)
+#define to_rpmsg_driver(d) container_of(d, struct rpmsg_driver, drv)
+
+/**
+ * struct rpmsg_device_ops - indirection table for the rpmsg_device operations
+ * @create_ept:		create backend-specific endpoint, requried
+ * @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_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 *ept);
+	int (*announce_destroy)(struct rpmsg_device *ept);
+};
+
+/**
+ * struct rpmsg_endpoint_ops - indirection table for rpmsg_endpoint operations
+ * @destroy_ept:	destroy the given endpoint, required
+ * @send:		see @rpmsg_send(), required
+ * @sendto:		see @rpmsg_sendto(), optional
+ * @send_offchannel:	see @rpmsg_send_offchannel(), optional
+ * @trysend:		see @rpmsg_trysend(), required
+ * @trysendto:		see @rpmsg_trysendto(), optional
+ * @trysend_offchannel:	see @rpmsg_trysend_offchannel(), optional
+ *
+ * Indirection table for the operations that a rpmsg backend should implement.
+ * In addition to @destroy_ept, the backend must at least implement @send and
+ * @trysend, while the variants sending data off-channel are optional.
+ */
+struct rpmsg_endpoint_ops {
+	void (*destroy_ept)(struct rpmsg_endpoint *ept);
+
+	int (*send)(struct rpmsg_endpoint *ept, void *data, int len);
+	int (*sendto)(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
+	int (*send_offchannel)(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+				  void *data, int len);
+
+	int (*trysend)(struct rpmsg_endpoint *ept, void *data, int len);
+	int (*trysendto)(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
+	int (*trysend_offchannel)(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+			     void *data, int len);
+};
+
+int rpmsg_register_device(struct rpmsg_device *rpdev);
+int rpmsg_unregister_device(struct device *parent,
+			    struct rpmsg_channel_info *chinfo);
+
+struct device *rpmsg_find_device(struct device *parent,
+				 struct rpmsg_channel_info *chinfo);
+
+#endif

drivers/rpmsg/virtio_rpmsg_bus.c

···
 #include <linux/wait.h>
 #include <linux/rpmsg.h>
 #include <linux/mutex.h>
+#include <linux/of_device.h>
+
+#include "rpmsg_internal.h"
 
 /**
  * struct virtproc_info - virtual remote processor state
···
 	struct rpmsg_endpoint *ns_ept;
 };
 
+/* The feature bitmap for virtio rpmsg */
+#define VIRTIO_RPMSG_F_NS	0 /* RP supports name service notifications */
+
 /**
- * struct rpmsg_channel_info - internal channel info representation
- * @name: name of service
- * @src: local address
+ * 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_channel_info {
-	char name[RPMSG_NAME_SIZE];
+struct rpmsg_hdr {
 	u32 src;
 	u32 dst;
+	u32 reserved;
+	u16 len;
+	u16 flags;
+	u8 data[0];
+} __packed;
+
+/**
+ * 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
+ * @flags: indicates whether service is created or destroyed
+ *
+ * This message is sent across to publish a new service, or announce
+ * about its removal. When we receive these messages, an appropriate
+ * rpmsg channel (i.e device) is created/destroyed. In turn, the ->probe()
+ * or ->remove() 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;
+	u32 flags;
+} __packed;
+
+/**
+ * enum rpmsg_ns_flags - dynamic name service announcement flags
+ *
+ * @RPMSG_NS_CREATE: a new remote service was just created
+ * @RPMSG_NS_DESTROY: a known remote service was just destroyed
+ */
+enum rpmsg_ns_flags {
+	RPMSG_NS_CREATE		= 0,
+	RPMSG_NS_DESTROY	= 1,
 };
 
-#define to_rpmsg_channel(d) container_of(d, struct rpmsg_channel, dev)
-#define to_rpmsg_driver(d) container_of(d, struct rpmsg_driver, drv)
+/**
+ * @vrp: the remote processor this channel belongs to
+ */
+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
···
 /* Address 53 is reserved for advertising remote services */
 #define RPMSG_NS_ADDR			(53)
 
-/* 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_channel *rpdev = to_rpmsg_channel(dev);		\
-									\
-	return sprintf(buf, format_string, rpdev->path);		\
-}
+static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept);
+static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
+static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
+			       u32 dst);
+static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
+					u32 dst, void *data, int len);
+static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
+static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
+				  int len, u32 dst);
+static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
+					   u32 dst, void *data, int len);
 
-/* 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");
-
-/*
- * Unique (and free running) index for rpmsg devices.
- *
- * Yeah, we're not recycling those numbers (yet?). will be easy
- * to change if/when we want to.
- */
-static unsigned int rpmsg_dev_index;
-
-static ssize_t modalias_show(struct device *dev,
-			     struct device_attribute *attr, char *buf)
-{
-	struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
-
-	return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name);
-}
-
-static struct device_attribute rpmsg_dev_attrs[] = {
-	__ATTR_RO(name),
-	__ATTR_RO(modalias),
-	__ATTR_RO(dst),
-	__ATTR_RO(src),
-	__ATTR_RO(announce),
-	__ATTR_NULL
+static const struct rpmsg_endpoint_ops virtio_endpoint_ops = {
+	.destroy_ept = virtio_rpmsg_destroy_ept,
+	.send = virtio_rpmsg_send,
+	.sendto = virtio_rpmsg_sendto,
+	.send_offchannel = virtio_rpmsg_send_offchannel,
+	.trysend = virtio_rpmsg_trysend,
+	.trysendto = virtio_rpmsg_trysendto,
+	.trysend_offchannel = virtio_rpmsg_trysend_offchannel,
 };
-
-/* rpmsg devices and drivers are matched using the service name */
-static inline int rpmsg_id_match(const struct rpmsg_channel *rpdev,
-				  const struct rpmsg_device_id *id)
-{
-	return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0;
-}
-
-/* match rpmsg channel and rpmsg driver */
-static int rpmsg_dev_match(struct device *dev, struct device_driver *drv)
-{
-	struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
-	struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
-	const struct rpmsg_device_id *ids = rpdrv->id_table;
-	unsigned int i;
-
-	for (i = 0; ids[i].name[0]; i++)
-		if (rpmsg_id_match(rpdev, &ids[i]))
-			return 1;
-
-	return 0;
-}
-
-static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env)
-{
-	struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
-
-	return add_uevent_var(env, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT,
-					rpdev->id.name);
-}
 
 /**
  * __ept_release() - deallocate an rpmsg endpoint
···
 
 /* for more info, see below documentation of rpmsg_create_ept() */
 static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp,
-		struct rpmsg_channel *rpdev, rpmsg_rx_cb_t cb,
-		void *priv, u32 addr)
+						 struct rpmsg_device *rpdev,
+						 rpmsg_rx_cb_t cb,
+						 void *priv, u32 addr)
 {
 	int id_min, id_max, id;
 	struct rpmsg_endpoint *ept;
 	struct device *dev = rpdev ? &rpdev->dev : &vrp->vdev->dev;
 
 	ept = kzalloc(sizeof(*ept), GFP_KERNEL);
-	if (!ept) {
-		dev_err(dev, "failed to kzalloc a new ept\n");
+	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) {
···
 	return NULL;
 }
 
-/**
- * rpmsg_create_ept() - create a new rpmsg_endpoint
- * @rpdev: rpmsg channel device
- * @cb: rx callback handler
- * @priv: private data for the driver's use
- * @addr: 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 do 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).
- *
- * Returns a pointer to the endpoint on success, or NULL on error.
- */
-struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *rpdev,
-				rpmsg_rx_cb_t cb, void *priv, u32 addr)
+static struct rpmsg_endpoint *virtio_rpmsg_create_ept(struct rpmsg_device *rpdev,
+						      rpmsg_rx_cb_t cb,
+						      void *priv,
+						      struct rpmsg_channel_info chinfo)
 {
-	return __rpmsg_create_ept(rpdev->vrp, rpdev, cb, priv, addr);
+	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
+
+	return __rpmsg_create_ept(vch->vrp, rpdev, cb, priv, chinfo.src);
 }
-EXPORT_SYMBOL(rpmsg_create_ept);
 
 /**
  * __rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
···
 	kref_put(&ept->refcount, __ept_release);
 }
 
-/**
- * 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().
- */
-void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
+static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
 {
-	__rpmsg_destroy_ept(ept->rpdev->vrp, ept);
+	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(ept->rpdev);
+
+	__rpmsg_destroy_ept(vch->vrp, ept);
 }
-EXPORT_SYMBOL(rpmsg_destroy_ept);
 
-/*
- * 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)
+static int virtio_rpmsg_announce_create(struct rpmsg_device *rpdev)
 {
-	struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
-	struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
-	struct virtproc_info *vrp = rpdev->vrp;
-	struct rpmsg_endpoint *ept;
-	int err;
-
-	ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, rpdev->src);
-	if (!ept) {
-		dev_err(dev, "failed to create endpoint\n");
-		err = -ENOMEM;
-		goto out;
-	}
-
-	rpdev->ept = ept;
-	rpdev->src = ept->addr;
-
-	err = rpdrv->probe(rpdev);
-	if (err) {
-		dev_err(dev, "%s: failed: %d\n", __func__, err);
-		rpmsg_destroy_ept(ept);
-		goto out;
-	}
+	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 &&
-			virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
+	    virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
 		struct rpmsg_ns_msg nsm;
 
 		strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
-		nsm.addr = rpdev->src;
+		nsm.addr = rpdev->ept->addr;
 		nsm.flags = RPMSG_NS_CREATE;
 
-		err = rpmsg_sendto(rpdev, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
+		err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
 		if (err)
 			dev_err(dev, "failed to announce service %d\n", err);
 	}
 
-out:
 	return err;
 }
 
-static int rpmsg_dev_remove(struct device *dev)
+static int virtio_rpmsg_announce_destroy(struct rpmsg_device *rpdev)
 {
-	struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
-	struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
-	struct virtproc_info *vrp = rpdev->vrp;
+	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 &&
-			virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
+	    virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
 		struct rpmsg_ns_msg nsm;
 
 		strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
 		nsm.addr = rpdev->src;
 		nsm.flags = RPMSG_NS_DESTROY;
 
-		err = rpmsg_sendto(rpdev, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
+		err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
 		if (err)
 			dev_err(dev, "failed to announce service %d\n", err);
 	}
 
-	rpdrv->remove(rpdev);
-
-	rpmsg_destroy_ept(rpdev->ept);
-
 	return err;
 }
 
-static struct bus_type rpmsg_bus = {
-	.name		= "rpmsg",
-	.match		= rpmsg_dev_match,
-	.dev_attrs	= rpmsg_dev_attrs,
-	.uevent		= rpmsg_uevent,
-	.probe		= rpmsg_dev_probe,
-	.remove		= rpmsg_dev_remove,
+static const struct rpmsg_device_ops virtio_rpmsg_ops = {
+	.create_ept = virtio_rpmsg_create_ept,
+	.announce_create = virtio_rpmsg_announce_create,
+	.announce_destroy = virtio_rpmsg_announce_destroy,
 };
-
-/**
- * __register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus
- * @rpdrv: pointer to a struct rpmsg_driver
- * @owner: owning module/driver
- *
- * Returns 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
- *
- * Returns 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 void rpmsg_release_device(struct device *dev)
-{
-	struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
-
-	kfree(rpdev);
-}
-
-/*
- * match an 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_channel_match(struct device *dev, void *data)
-{
-	struct rpmsg_channel_info *chinfo = data;
-	struct rpmsg_channel *rpdev = to_rpmsg_channel(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;
-}
 
 /*
  * 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_channel *rpmsg_create_channel(struct virtproc_info *vrp,
-				struct rpmsg_channel_info *chinfo)
+static struct rpmsg_device *rpmsg_create_channel(struct virtproc_info *vrp,
+						 struct rpmsg_channel_info *chinfo)
 {
-	struct rpmsg_channel *rpdev;
+	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 = device_find_child(dev, chinfo, rpmsg_channel_match);
+	tmp = rpmsg_find_device(dev, chinfo);
 	if (tmp) {
 		/* decrement the matched device's refcount back */
 		put_device(tmp);
···
 		return NULL;
 	}
 
-	rpdev = kzalloc(sizeof(struct rpmsg_channel), GFP_KERNEL);
-	if (!rpdev) {
-		pr_err("kzalloc failed\n");
+	vch = kzalloc(sizeof(*vch), GFP_KERNEL);
+	if (!vch)
 		return NULL;
-	}
 
-	rpdev->vrp = vrp;
+	/* Link the channel to our vrp */
+	vch->vrp = vrp;
+
+	/* Assign callbacks for rpmsg_channel */
+	vch->rpdev.ops = &virtio_rpmsg_ops;
+
+	/* Assign public information to the rpmsg_device */
+	rpdev = &vch->rpdev;
 	rpdev->src = chinfo->src;
 	rpdev->dst = chinfo->dst;
+	rpdev->ops = &virtio_rpmsg_ops;
 
 	/*
 	 * rpmsg server channels has predefined local address (for now),
 	 * and their existence needs to be announced remotely
 	 */
-	rpdev->announce = rpdev->src != RPMSG_ADDR_ANY ? true : false;
+	rpdev->announce = rpdev->src != RPMSG_ADDR_ANY;
 
 	strncpy(rpdev->id.name, chinfo->name, RPMSG_NAME_SIZE);
 
-	/* very simple device indexing plumbing which is enough for now */
-	dev_set_name(&rpdev->dev, "rpmsg%d", rpmsg_dev_index++);
-
 	rpdev->dev.parent = &vrp->vdev->dev;
-	rpdev->dev.bus = &rpmsg_bus;
-	rpdev->dev.release = rpmsg_release_device;
-
-	ret = device_register(&rpdev->dev);
-	if (ret) {
-		dev_err(dev, "device_register failed: %d\n", ret);
-		put_device(&rpdev->dev);
+	ret = rpmsg_register_device(rpdev);
+	if (ret)
 		return NULL;
-	}
 
 	return rpdev;
-}
-
-/*
- * find an existing channel using its name + address properties,
- * and destroy it
- */
-static int rpmsg_destroy_channel(struct virtproc_info *vrp,
-					struct rpmsg_channel_info *chinfo)
-{
-	struct virtio_device *vdev = vrp->vdev;
-	struct device *dev;
-
-	dev = device_find_child(&vdev->dev, chinfo, rpmsg_channel_match);
-	if (!dev)
-		return -EINVAL;
-
-	device_unregister(dev);
-
-	put_device(dev);
-
-	return 0;
 }
 
 /* super simple buffer "allocator" that is just enough for now */
···
  *
  * Returns 0 on success and an appropriate error value on failure.
  */
-int rpmsg_send_offchannel_raw(struct rpmsg_channel *rpdev, u32 src, u32 dst,
-					void *data, int len, bool wait)
+static int rpmsg_send_offchannel_raw(struct rpmsg_device *rpdev,
+				     u32 src, u32 dst,
+				     void *data, int len, bool wait)
 {
-	struct virtproc_info *vrp = rpdev->vrp;
+	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;
···
 	memcpy(msg->data, data, len);
 
 	dev_dbg(dev, "TX From 0x%x, To 0x%x, Len %d, Flags %d, Reserved %d\n",
-					msg->src, msg->dst, msg->len,
-					msg->flags, msg->reserved);
-	print_hex_dump(KERN_DEBUG, "rpmsg_virtio TX: ", DUMP_PREFIX_NONE, 16, 1,
-					msg, sizeof(*msg) + msg->len, true);
+		msg->src, msg->dst, msg->len, msg->flags, msg->reserved);
+#if defined(CONFIG_DYNAMIC_DEBUG)
+	dynamic_hex_dump("rpmsg_virtio TX: ", DUMP_PREFIX_NONE, 16, 1,
+			 msg, sizeof(*msg) + msg->len, true);
+#endif
 
 	sg_init_one(&sg, msg, sizeof(*msg) + len);
 
···
 }
 EXPORT_SYMBOL(rpmsg_send_offchannel_raw);
 
+static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+	u32 src = ept->addr, dst = rpdev->dst;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
+}
+
+static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
+			       u32 dst)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+	u32 src = ept->addr;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
+}
+
+static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
+					u32 dst, void *data, int len)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
+}
+
+static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+	u32 src = ept->addr, dst = rpdev->dst;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
+}
+
+static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
+				  int len, u32 dst)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+	u32 src = ept->addr;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
+}
+
+static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
+					   u32 dst, void *data, int len)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
+}
+
 static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
 			     struct rpmsg_hdr *msg, unsigned int len)
 {
···
 	int err;
 
 	dev_dbg(dev, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n",
-					msg->src, msg->dst, msg->len,
-					msg->flags, msg->reserved);
-	print_hex_dump(KERN_DEBUG, "rpmsg_virtio RX: ", DUMP_PREFIX_NONE, 16, 1,
-					msg, sizeof(*msg) + msg->len, true);
+		msg->src, msg->dst, msg->len, msg->flags, 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 > RPMSG_BUF_SIZE ||
-		msg->len > (len - sizeof(struct rpmsg_hdr))) {
+	    msg->len > (len - sizeof(struct rpmsg_hdr))) {
 		dev_warn(dev, "inbound msg too big: (%d, %d)\n", len, msg->len);
 		return -EINVAL;
 	}
···
 		msgs_received++;
 
 		msg = virtqueue_get_buf(rvq, &len);
-	};
+	}
 
 	dev_dbg(dev, "Received %u messages\n", msgs_received);
 
···
 }
 
 /* invoked when a name service announcement arrives */
-static void rpmsg_ns_cb(struct rpmsg_channel *rpdev, void *data, int len,
-							void *priv, u32 src)
+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_channel *newch;
+	struct rpmsg_device *newch;
 	struct rpmsg_channel_info chinfo;
 	struct virtproc_info *vrp = priv;
 	struct device *dev = &vrp->vdev->dev;
 	int ret;
 
-	print_hex_dump(KERN_DEBUG, "NS announcement: ",
-			DUMP_PREFIX_NONE, 16, 1,
-			data, len, true);
+#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;
+		return -EINVAL;
 	}
 
 	/*
···
 	 */
 	if (rpdev) {
 		dev_err(dev, "anomaly: ns ept has an rpdev handle\n");
-		return;
+		return -EINVAL;
 	}
 
 	/* don't trust the remote processor for null terminating the name */
 	msg->name[RPMSG_NAME_SIZE - 1] = '\0';
 
 	dev_info(dev, "%sing channel %s addr 0x%x\n",
-			msg->flags & RPMSG_NS_DESTROY ? "destroy" : "creat",
-			msg->name, msg->addr);
+		 msg->flags & RPMSG_NS_DESTROY ? "destroy" : "creat",
+		 msg->name, msg->addr);
 
 	strncpy(chinfo.name, msg->name, sizeof(chinfo.name));
 	chinfo.src = RPMSG_ADDR_ANY;
 	chinfo.dst = msg->addr;
 
 	if (msg->flags & RPMSG_NS_DESTROY) {
-		ret = rpmsg_destroy_channel(vrp, &chinfo);
+		ret = rpmsg_unregister_device(&vrp->vdev->dev, &chinfo);
 		if (ret)
 			dev_err(dev, "rpmsg_destroy_channel failed: %d\n", ret);
 	} else {
···
 		if (!newch)
 			dev_err(dev, "rpmsg_create_channel failed\n");
 	}
+
+	return 0;
 }
 
 static int rpmsg_probe(struct virtio_device *vdev)
···
 		goto vqs_del;
 	}
 
-	dev_dbg(&vdev->dev, "buffers: va %p, dma 0x%llx\n", bufs_va,
-					(unsigned long long)vrp->bufs_dma);
+	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;
···
 		sg_init_one(&sg, cpu_addr, RPMSG_BUF_SIZE);
 
 		err = virtqueue_add_inbuf(vrp->rvq, &sg, 1, cpu_addr,
-								GFP_KERNEL);
+					  GFP_KERNEL);
 		WARN_ON(err); /* sanity check; this can't really happen */
 	}
 
···
 {
 	int ret;
 
-	ret = bus_register(&rpmsg_bus);
-	if (ret) {
-		pr_err("failed to register rpmsg bus: %d\n", ret);
-		return ret;
-	}
-
 	ret = register_virtio_driver(&virtio_ipc_driver);
-	if (ret) {
+	if (ret)
 		pr_err("failed to register virtio driver: %d\n", ret);
-		bus_unregister(&rpmsg_bus);
-	}
 
 	return ret;
 }
···
 static void __exit rpmsg_fini(void)
 {
 	unregister_virtio_driver(&virtio_ipc_driver);
-	bus_unregister(&rpmsg_bus);
 }
 module_exit(rpmsg_fini);
 

include/linux/rpmsg.h

···
 #include <linux/kref.h>
 #include <linux/mutex.h>
 
-/* 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 {
-	u32 src;
-	u32 dst;
-	u32 reserved;
-	u16 len;
-	u16 flags;
-	u8 data[0];
-} __packed;
-
-/**
- * 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
- * @flags: indicates whether service is created or destroyed
- *
- * This message is sent across to publish a new service, or announce
- * about its removal. When we receive these messages, an appropriate
- * rpmsg channel (i.e device) is created/destroyed. In turn, the ->probe()
- * or ->remove() 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;
-	u32 flags;
-} __packed;
-
-/**
- * enum rpmsg_ns_flags - dynamic name service announcement flags
- *
- * @RPMSG_NS_CREATE: a new remote service was just created
- * @RPMSG_NS_DESTROY: a known remote service was just destroyed
- */
-enum rpmsg_ns_flags {
-	RPMSG_NS_CREATE		= 0,
-	RPMSG_NS_DESTROY	= 1,
-};
-
 #define RPMSG_ADDR_ANY		0xFFFFFFFF
 
-struct virtproc_info;
+struct rpmsg_device;
+struct rpmsg_endpoint;
+struct rpmsg_device_ops;
+struct rpmsg_endpoint_ops;
 
 /**
- * rpmsg_channel - devices that belong to the rpmsg bus are called channels
- * @vrp: the remote processor this channel belongs to
+ * struct rpmsg_channel_info - channel info representation
+ * @name: name of service
+ * @src: local address
+ * @dst: destination address
+ */
+struct rpmsg_channel_info {
+	char name[RPMSG_NAME_SIZE];
+	u32 src;
+	u32 dst;
+};
+
+/**
+ * rpmsg_device - device that belong to the rpmsg bus
  * @dev: the device struct
  * @id: device id (used to match between rpmsg drivers and devices)
  * @src: local address
···
  * @ept: the rpmsg endpoint of this channel
  * @announce: if set, rpmsg will announce the creation/removal of this channel
  */
-struct rpmsg_channel {
-	struct virtproc_info *vrp;
+struct rpmsg_device {
 	struct device dev;
 	struct rpmsg_device_id id;
 	u32 src;
 	u32 dst;
 	struct rpmsg_endpoint *ept;
 	bool announce;
+
+	const struct rpmsg_device_ops *ops;
 };
 
-typedef void (*rpmsg_rx_cb_t)(struct rpmsg_channel *, void *, int, void *, u32);
+typedef int (*rpmsg_rx_cb_t)(struct rpmsg_device *, void *, int, void *, u32);
 
 /**
  * struct rpmsg_endpoint - binds a local rpmsg address to its user
···
  * create additional endpoints by themselves (see rpmsg_create_ept()).
  */
 struct rpmsg_endpoint {
-	struct rpmsg_channel *rpdev;
+	struct rpmsg_device *rpdev;
 	struct kref refcount;
 	rpmsg_rx_cb_t cb;
 	struct mutex cb_lock;
 	u32 addr;
 	void *priv;
+
+	const struct rpmsg_endpoint_ops *ops;
 };
 
 /**
···
 struct rpmsg_driver {
 	struct device_driver drv;
 	const struct rpmsg_device_id *id_table;
-	int (*probe)(struct rpmsg_channel *dev);
-	void (*remove)(struct rpmsg_channel *dev);
-	void (*callback)(struct rpmsg_channel *, void *, int, void *, u32);
+	int (*probe)(struct rpmsg_device *dev);
+	void (*remove)(struct rpmsg_device *dev);
+	int (*callback)(struct rpmsg_device *, void *, int, void *, u32);
 };
 
-int register_rpmsg_device(struct rpmsg_channel *dev);
-void unregister_rpmsg_device(struct rpmsg_channel *dev);
+int register_rpmsg_device(struct rpmsg_device *dev);
+void unregister_rpmsg_device(struct rpmsg_device *dev);
 int __register_rpmsg_driver(struct rpmsg_driver *drv, struct module *owner);
 void unregister_rpmsg_driver(struct rpmsg_driver *drv);
 void rpmsg_destroy_ept(struct rpmsg_endpoint *);
-struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *,
-				rpmsg_rx_cb_t cb, void *priv, u32 addr);
-int
-rpmsg_send_offchannel_raw(struct rpmsg_channel *, u32, u32, void *, int, bool);
+struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *,
+					rpmsg_rx_cb_t cb, void *priv,
+					struct rpmsg_channel_info chinfo);
 
 /* use a macro to avoid include chaining to get THIS_MODULE */
 #define register_rpmsg_driver(drv) \
···
 	module_driver(__rpmsg_driver, register_rpmsg_driver, \
 			unregister_rpmsg_driver)
 
-/**
- * rpmsg_send() - send a message across to the remote processor
- * @rpdev: the rpmsg channel
- * @data: payload of message
- * @len: length of payload
- *
- * This function sends @data of length @len on the @rpdev channel.
- * The message will be sent to the remote processor which the @rpdev
- * channel belongs to, using @rpdev's source and 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).
- *
- * Returns 0 on success and an appropriate error value on failure.
- */
-static inline int rpmsg_send(struct rpmsg_channel *rpdev, void *data, int len)
-{
-	u32 src = rpdev->src, dst = rpdev->dst;
+int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
+int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
+int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+			  void *data, int len);
 
-	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
-}
-
-/**
- * rpmsg_sendto() - send a message across to the remote processor, specify dst
- * @rpdev: the rpmsg channel
- * @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 @rpdev
- * channel belongs to, using @rpdev's source address.
- * 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).
- *
- * Returns 0 on success and an appropriate error value on failure.
- */
-static inline
-int rpmsg_sendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
-{
-	u32 src = rpdev->src;
-
-	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
-}
-
-/**
- * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
- * @rpdev: the rpmsg channel
- * @src: source address
- * @dst: destination address
- * @data: payload of message
- * @len: length of payload
- *
- * This function sends @data of length @len to the remote @dst address,
- * and uses @src as the source address.
- * The message will be sent to the remote processor which the @rpdev
- * channel belongs to.
- * In case there are no TX buffers available, the function will block until
- * one becomes available, or a timeout of 15 seconds elapses. When the latter
- * happens, -ERESTARTSYS is returned.
- *
- * Can only be called from process context (for now).
- *
- * Returns 0 on success and an appropriate error value on failure.
- */
-static inline
-int rpmsg_send_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
-							void *data, int len)
-{
-	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
-}
-
-/**
- * rpmsg_send() - send a message across to the remote processor
- * @rpdev: the rpmsg channel
- * @data: payload of message
- * @len: length of payload
- *
- * This function sends @data of length @len on the @rpdev channel.
- * The message will be sent to the remote processor which the @rpdev
- * channel belongs to, using @rpdev's source and destination addresses.
- * 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).
- *
- * Returns 0 on success and an appropriate error value on failure.
- */
-static inline
-int rpmsg_trysend(struct rpmsg_channel *rpdev, void *data, int len)
-{
-	u32 src = rpdev->src, dst = rpdev->dst;
-
-	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
-}
-
-/**
- * rpmsg_sendto() - send a message across to the remote processor, specify dst
- * @rpdev: the rpmsg channel
- * @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 @rpdev
- * channel belongs to, using @rpdev's source address.
- * 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).
- *
- * Returns 0 on success and an appropriate error value on failure.
- */
-static inline
-int rpmsg_trysendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
-{
-	u32 src = rpdev->src;
-
-	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
-}
-
-/**
- * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
- * @rpdev: the rpmsg channel
- * @src: source address
- * @dst: destination address
- * @data: payload of message
- * @len: length of payload
- *
- * This function sends @data of length @len to the remote @dst address,
- * and uses @src as the source address.
- * The message will be sent to the remote processor which the @rpdev
- * channel belongs to.
- * In case there are no TX buffers available, the function will immediately
- * return -ENOMEM without waiting until one becomes available.
- *
- * Can only be called from process context (for now).
- *
- * Returns 0 on success and an appropriate error value on failure.
- */
-static inline
-int rpmsg_trysend_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
-							void *data, int len)
-{
-	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
-}
+int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
+int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
+int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+			     void *data, int len);
 
 #endif /* _LINUX_RPMSG_H */

samples/rpmsg/rpmsg_client_sample.c

···
 #define MSG		"hello world!"
 #define MSG_LIMIT	100
 
-static void rpmsg_sample_cb(struct rpmsg_channel *rpdev, void *data, int len,
+struct instance_data {
+	int rx_count;
+};
+
+static int rpmsg_sample_cb(struct rpmsg_device *rpdev, void *data, int len,
 						void *priv, u32 src)
 {
 	int ret;
-	static int rx_count;
+	struct instance_data *idata = dev_get_drvdata(&rpdev->dev);
 
-	dev_info(&rpdev->dev, "incoming msg %d (src: 0x%x)\n", ++rx_count, src);
+	dev_info(&rpdev->dev, "incoming msg %d (src: 0x%x)\n",
+		 ++idata->rx_count, src);
 
 	print_hex_dump(KERN_DEBUG, __func__, DUMP_PREFIX_NONE, 16, 1,
 		       data, len,  true);
 
 	/* samples should not live forever */
-	if (rx_count >= MSG_LIMIT) {
+	if (idata->rx_count >= MSG_LIMIT) {
 		dev_info(&rpdev->dev, "goodbye!\n");
-		return;
+		return 0;
 	}
 
 	/* send a new message now */
-	ret = rpmsg_send(rpdev, MSG, strlen(MSG));
+	ret = rpmsg_send(rpdev->ept, MSG, strlen(MSG));
 	if (ret)
 		dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", ret);
+
+	return 0;
 }
 
-static int rpmsg_sample_probe(struct rpmsg_channel *rpdev)
+static int rpmsg_sample_probe(struct rpmsg_device *rpdev)
 {
 	int ret;
+	struct instance_data *idata;
 
 	dev_info(&rpdev->dev, "new channel: 0x%x -> 0x%x!\n",
 					rpdev->src, rpdev->dst);
 
+	idata = devm_kzalloc(&rpdev->dev, sizeof(*idata), GFP_KERNEL);
+	if (!idata)
+		return -ENOMEM;
+
+	dev_set_drvdata(&rpdev->dev, idata);
+
 	/* send a message to our remote processor */
-	ret = rpmsg_send(rpdev, MSG, strlen(MSG));
+	ret = rpmsg_send(rpdev->ept, MSG, strlen(MSG));
 	if (ret) {
 		dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", ret);
 		return ret;
···
 	return 0;
 }
 
-static void rpmsg_sample_remove(struct rpmsg_channel *rpdev)
+static void rpmsg_sample_remove(struct rpmsg_device *rpdev)
 {
 	dev_info(&rpdev->dev, "rpmsg sample client driver is removed\n");
 }