add MOST-Linux-Driver sources

This patch adds the sources of the MOST-Linux-Driver to AGL's /src
directory.
Gitlab commit: b0ab66aac15096ed7701b95ffc188bcceb71e55b

Change-Id: I82a57f1c0b605aa8d5e320eb8f14ad932603f63b
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>

2 files changed, 2281 insertions, 0 deletions

diff --git a/driver/mostcore/core.c b/driver/mostcore/core.c
new file mode 100644
index 0000000..81dbac9
--- /dev/null
+++ b/driver/mostcore/core.c
@@ -0,0 +1,1961 @@
+/*
+ * core.c - Implementation of core module of MOST Linux driver stack
+ *
+ * Copyright (C) 2013-2015 Microchip Technology Germany II GmbH & Co. KG
+ *
+ * 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.
+ *
+ * This file is licensed under GPLv2.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/poll.h>
+#include <linux/wait.h>
+#include <linux/kobject.h>
+#include <linux/mutex.h>
+#include <linux/completion.h>
+#include <linux/sysfs.h>
+#include <linux/kthread.h>
+#include <linux/dma-mapping.h>
+#include <linux/idr.h>
+#include "mostcore.h"
+
+#define MAX_CHANNELS	64
+#define STRING_SIZE	80
+
+static struct class *most_class;
+static struct device *core_dev;
+static struct ida mdev_id;
+static int dummy_num_buffers;
+
+struct most_c_aim_obj {
+	struct most_aim *ptr;
+	int refs;
+	int num_buffers;
+};
+
+struct most_c_obj {
+	struct kobject kobj;
+	struct completion cleanup;
+	atomic_t mbo_ref;
+	atomic_t mbo_nq_level;
+	u16 channel_id;
+	bool is_poisoned;
+	struct mutex start_mutex;
+	struct mutex nq_mutex;
+	int is_starving;
+	struct most_interface *iface;
+	struct most_inst_obj *inst;
+	struct most_channel_config cfg;
+	bool keep_mbo;
+	bool enqueue_halt;
+	struct list_head fifo;
+	spinlock_t fifo_lock;
+	struct list_head halt_fifo;
+	struct list_head list;
+	struct most_c_aim_obj aim0;
+	struct most_c_aim_obj aim1;
+	struct list_head trash_fifo;
+	struct task_struct *hdm_enqueue_task;
+	wait_queue_head_t hdm_fifo_wq;
+};
+
+#define to_c_obj(d) container_of(d, struct most_c_obj, kobj)
+
+struct most_inst_obj {
+	int dev_id;
+	struct most_interface *iface;
+	struct list_head channel_list;
+	struct most_c_obj *channel[MAX_CHANNELS];
+	struct kobject kobj;
+	struct list_head list;
+};
+
+static const struct {
+	int most_ch_data_type;
+	char *name;
+} ch_data_type[] = { { MOST_CH_CONTROL, "control\n" },
+	{ MOST_CH_ASYNC, "async\n" },
+	{ MOST_CH_SYNC, "sync\n" },
+	{ MOST_CH_ISOC_AVP, "isoc_avp\n"} };
+
+#define to_inst_obj(d) container_of(d, struct most_inst_obj, kobj)
+
+/**
+ * list_pop_mbo - retrieves the first MBO of the list and removes it
+ * @ptr: the list head to grab the MBO from.
+ */
+#define list_pop_mbo(ptr)						\
+({									\
+	struct mbo *_mbo = list_first_entry(ptr, struct mbo, list);	\
+	list_del(&_mbo->list);						\
+	_mbo;								\
+})
+
+/*		     ___	     ___
+ *		     ___C H A N N E L___
+ */
+
+/**
+ * struct most_c_attr - to access the attributes of a channel object
+ * @attr: attributes of a channel
+ * @show: pointer to the show function
+ * @store: pointer to the store function
+ */
+struct most_c_attr {
+	struct attribute attr;
+	ssize_t (*show)(struct most_c_obj *d,
+			struct most_c_attr *attr,
+			char *buf);
+	ssize_t (*store)(struct most_c_obj *d,
+			 struct most_c_attr *attr,
+			 const char *buf,
+			 size_t count);
+};
+
+#define to_channel_attr(a) container_of(a, struct most_c_attr, attr)
+
+#define MOST_CHNL_ATTR(_name, _mode, _show, _store) \
+		struct most_c_attr most_chnl_attr_##_name = \
+		__ATTR(_name, _mode, _show, _store)
+
+/**
+ * channel_attr_show - show function of channel object
+ * @kobj: pointer to its kobject
+ * @attr: pointer to its attributes
+ * @buf: buffer
+ */
+static ssize_t channel_attr_show(struct kobject *kobj, struct attribute *attr,
+				 char *buf)
+{
+	struct most_c_attr *channel_attr = to_channel_attr(attr);
+	struct most_c_obj *c_obj = to_c_obj(kobj);
+
+	if (!channel_attr->show)
+		return -EIO;
+
+	return channel_attr->show(c_obj, channel_attr, buf);
+}
+
+/**
+ * channel_attr_store - store function of channel object
+ * @kobj: pointer to its kobject
+ * @attr: pointer to its attributes
+ * @buf: buffer
+ * @len: length of buffer
+ */
+static ssize_t channel_attr_store(struct kobject *kobj,
+				  struct attribute *attr,
+				  const char *buf,
+				  size_t len)
+{
+	struct most_c_attr *channel_attr = to_channel_attr(attr);
+	struct most_c_obj *c_obj = to_c_obj(kobj);
+
+	if (!channel_attr->store)
+		return -EIO;
+	return channel_attr->store(c_obj, channel_attr, buf, len);
+}
+
+static const struct sysfs_ops most_channel_sysfs_ops = {
+	.show = channel_attr_show,
+	.store = channel_attr_store,
+};
+
+/**
+ * most_free_mbo_coherent - free an MBO and its coherent buffer
+ * @mbo: buffer to be released
+ *
+ */
+static void most_free_mbo_coherent(struct mbo *mbo)
+{
+	struct most_c_obj *c = mbo->context;
+	u16 const coherent_buf_size = c->cfg.buffer_size + c->cfg.extra_len;
+
+	dma_free_coherent(NULL, coherent_buf_size, mbo->virt_address,
+			  mbo->bus_address);
+	kfree(mbo);
+	if (atomic_sub_and_test(1, &c->mbo_ref))
+		complete(&c->cleanup);
+}
+
+/**
+ * flush_channel_fifos - clear the channel fifos
+ * @c: pointer to channel object
+ */
+static void flush_channel_fifos(struct most_c_obj *c)
+{
+	unsigned long flags, hf_flags;
+	struct mbo *mbo, *tmp;
+
+	if (list_empty(&c->fifo) && list_empty(&c->halt_fifo))
+		return;
+
+	spin_lock_irqsave(&c->fifo_lock, flags);
+	list_for_each_entry_safe(mbo, tmp, &c->fifo, list) {
+		list_del(&mbo->list);
+		spin_unlock_irqrestore(&c->fifo_lock, flags);
+		most_free_mbo_coherent(mbo);
+		spin_lock_irqsave(&c->fifo_lock, flags);
+	}
+	spin_unlock_irqrestore(&c->fifo_lock, flags);
+
+	spin_lock_irqsave(&c->fifo_lock, hf_flags);
+	list_for_each_entry_safe(mbo, tmp, &c->halt_fifo, list) {
+		list_del(&mbo->list);
+		spin_unlock_irqrestore(&c->fifo_lock, hf_flags);
+		most_free_mbo_coherent(mbo);
+		spin_lock_irqsave(&c->fifo_lock, hf_flags);
+	}
+	spin_unlock_irqrestore(&c->fifo_lock, hf_flags);
+
+	if (unlikely((!list_empty(&c->fifo) || !list_empty(&c->halt_fifo))))
+		pr_info("WARN: fifo | trash fifo not empty\n");
+}
+
+/**
+ * flush_trash_fifo - clear the trash fifo
+ * @c: pointer to channel object
+ */
+static int flush_trash_fifo(struct most_c_obj *c)
+{
+	struct mbo *mbo, *tmp;
+	unsigned long flags;
+
+	spin_lock_irqsave(&c->fifo_lock, flags);
+	list_for_each_entry_safe(mbo, tmp, &c->trash_fifo, list) {
+		list_del(&mbo->list);
+		spin_unlock_irqrestore(&c->fifo_lock, flags);
+		most_free_mbo_coherent(mbo);
+		spin_lock_irqsave(&c->fifo_lock, flags);
+	}
+	spin_unlock_irqrestore(&c->fifo_lock, flags);
+	return 0;
+}
+
+/**
+ * most_channel_release - release function of channel object
+ * @kobj: pointer to channel's kobject
+ */
+static void most_channel_release(struct kobject *kobj)
+{
+	struct most_c_obj *c = to_c_obj(kobj);
+
+	kfree(c);
+}
+
+static ssize_t show_available_directions(struct most_c_obj *c,
+					 struct most_c_attr *attr,
+					 char *buf)
+{
+	unsigned int i = c->channel_id;
+
+	strcpy(buf, "");
+	if (c->iface->channel_vector[i].direction & MOST_CH_RX)
+		strcat(buf, "dir_rx ");
+	if (c->iface->channel_vector[i].direction & MOST_CH_TX)
+		strcat(buf, "dir_tx ");
+	strcat(buf, "\n");
+	return strlen(buf) + 1;
+}
+
+static ssize_t show_available_datatypes(struct most_c_obj *c,
+					struct most_c_attr *attr,
+					char *buf)
+{
+	unsigned int i = c->channel_id;
+
+	strcpy(buf, "");
+	if (c->iface->channel_vector[i].data_type & MOST_CH_CONTROL)
+		strcat(buf, "control ");
+	if (c->iface->channel_vector[i].data_type & MOST_CH_ASYNC)
+		strcat(buf, "async ");
+	if (c->iface->channel_vector[i].data_type & MOST_CH_SYNC)
+		strcat(buf, "sync ");
+	if (c->iface->channel_vector[i].data_type & MOST_CH_ISOC_AVP)
+		strcat(buf, "isoc_avp ");
+	strcat(buf, "\n");
+	return strlen(buf) + 1;
+}
+
+static
+ssize_t show_number_of_packet_buffers(struct most_c_obj *c,
+				      struct most_c_attr *attr,
+				      char *buf)
+{
+	unsigned int i = c->channel_id;
+
+	return snprintf(buf, PAGE_SIZE, "%d\n",
+			c->iface->channel_vector[i].num_buffers_packet);
+}
+
+static
+ssize_t show_number_of_stream_buffers(struct most_c_obj *c,
+				      struct most_c_attr *attr,
+				      char *buf)
+{
+	unsigned int i = c->channel_id;
+
+	return snprintf(buf, PAGE_SIZE, "%d\n",
+			c->iface->channel_vector[i].num_buffers_streaming);
+}
+
+static
+ssize_t show_size_of_packet_buffer(struct most_c_obj *c,
+				   struct most_c_attr *attr,
+				   char *buf)
+{
+	unsigned int i = c->channel_id;
+
+	return snprintf(buf, PAGE_SIZE, "%d\n",
+			c->iface->channel_vector[i].buffer_size_packet);
+}
+
+static
+ssize_t show_size_of_stream_buffer(struct most_c_obj *c,
+				   struct most_c_attr *attr,
+				   char *buf)
+{
+	unsigned int i = c->channel_id;
+
+	return snprintf(buf, PAGE_SIZE, "%d\n",
+			c->iface->channel_vector[i].buffer_size_streaming);
+}
+
+static ssize_t show_channel_starving(struct most_c_obj *c,
+				     struct most_c_attr *attr,
+				     char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", c->is_starving);
+}
+
+#define create_show_channel_attribute(val) \
+	static MOST_CHNL_ATTR(val, S_IRUGO, show_##val, NULL)
+
+create_show_channel_attribute(available_directions);
+create_show_channel_attribute(available_datatypes);
+create_show_channel_attribute(number_of_packet_buffers);
+create_show_channel_attribute(number_of_stream_buffers);
+create_show_channel_attribute(size_of_stream_buffer);
+create_show_channel_attribute(size_of_packet_buffer);
+create_show_channel_attribute(channel_starving);
+
+static ssize_t show_set_number_of_buffers(struct most_c_obj *c,
+					  struct most_c_attr *attr,
+					  char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.num_buffers);
+}
+
+static ssize_t store_set_number_of_buffers(struct most_c_obj *c,
+					   struct most_c_attr *attr,
+					   const char *buf,
+					   size_t count)
+{
+	int ret = kstrtou16(buf, 0, &c->cfg.num_buffers);
+
+	if (ret)
+		return ret;
+	return count;
+}
+
+static ssize_t show_set_buffer_size(struct most_c_obj *c,
+				    struct most_c_attr *attr,
+				    char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.buffer_size);
+}
+
+static ssize_t store_set_buffer_size(struct most_c_obj *c,
+				     struct most_c_attr *attr,
+				     const char *buf,
+				     size_t count)
+{
+	int ret = kstrtou16(buf, 0, &c->cfg.buffer_size);
+
+	if (ret)
+		return ret;
+	return count;
+}
+
+static ssize_t show_set_direction(struct most_c_obj *c,
+				  struct most_c_attr *attr,
+				  char *buf)
+{
+	if (c->cfg.direction & MOST_CH_TX)
+		return snprintf(buf, PAGE_SIZE, "dir_tx\n");
+	else if (c->cfg.direction & MOST_CH_RX)
+		return snprintf(buf, PAGE_SIZE, "dir_rx\n");
+	return snprintf(buf, PAGE_SIZE, "unconfigured\n");
+}
+
+static ssize_t store_set_direction(struct most_c_obj *c,
+				   struct most_c_attr *attr,
+				   const char *buf,
+				   size_t count)
+{
+	if (!strcmp(buf, "dir_rx\n")) {
+		c->cfg.direction = MOST_CH_RX;
+	} else if (!strcmp(buf, "dir_tx\n")) {
+		c->cfg.direction = MOST_CH_TX;
+	} else {
+		pr_info("WARN: invalid attribute settings\n");
+		return -EINVAL;
+	}
+	return count;
+}
+
+static ssize_t show_set_datatype(struct most_c_obj *c,
+				 struct most_c_attr *attr,
+				 char *buf)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ch_data_type); i++) {
+		if (c->cfg.data_type & ch_data_type[i].most_ch_data_type)
+			return snprintf(buf, PAGE_SIZE, ch_data_type[i].name);
+	}
+	return snprintf(buf, PAGE_SIZE, "unconfigured\n");
+}
+
+static ssize_t store_set_datatype(struct most_c_obj *c,
+				  struct most_c_attr *attr,
+				  const char *buf,
+				  size_t count)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ch_data_type); i++) {
+		if (!strcmp(buf, ch_data_type[i].name)) {
+			c->cfg.data_type = ch_data_type[i].most_ch_data_type;
+			break;
+		}
+	}
+
+	if (i == ARRAY_SIZE(ch_data_type)) {
+		pr_info("WARN: invalid attribute settings\n");
+		return -EINVAL;
+	}
+	return count;
+}
+
+static ssize_t show_set_subbuffer_size(struct most_c_obj *c,
+				       struct most_c_attr *attr,
+				       char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.subbuffer_size);
+}
+
+static ssize_t store_set_subbuffer_size(struct most_c_obj *c,
+					struct most_c_attr *attr,
+					const char *buf,
+					size_t count)
+{
+	int ret = kstrtou16(buf, 0, &c->cfg.subbuffer_size);
+
+	if (ret)
+		return ret;
+	return count;
+}
+
+static ssize_t show_set_packets_per_xact(struct most_c_obj *c,
+					 struct most_c_attr *attr,
+					 char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", c->cfg.packets_per_xact);
+}
+
+static ssize_t store_set_packets_per_xact(struct most_c_obj *c,
+					  struct most_c_attr *attr,
+					  const char *buf,
+					  size_t count)
+{
+	int ret = kstrtou16(buf, 0, &c->cfg.packets_per_xact);
+
+	if (ret)
+		return ret;
+	return count;
+}
+
+#define create_channel_attribute(value) \
+	static MOST_CHNL_ATTR(value, S_IRUGO | S_IWUSR, \
+			      show_##value, \
+			      store_##value)
+
+create_channel_attribute(set_buffer_size);
+create_channel_attribute(set_number_of_buffers);
+create_channel_attribute(set_direction);
+create_channel_attribute(set_datatype);
+create_channel_attribute(set_subbuffer_size);
+create_channel_attribute(set_packets_per_xact);
+
+/**
+ * most_channel_def_attrs - array of default attributes of channel object
+ */
+static struct attribute *most_channel_def_attrs[] = {
+	&most_chnl_attr_available_directions.attr,
+	&most_chnl_attr_available_datatypes.attr,
+	&most_chnl_attr_number_of_packet_buffers.attr,
+	&most_chnl_attr_number_of_stream_buffers.attr,
+	&most_chnl_attr_size_of_packet_buffer.attr,
+	&most_chnl_attr_size_of_stream_buffer.attr,
+	&most_chnl_attr_set_number_of_buffers.attr,
+	&most_chnl_attr_set_buffer_size.attr,
+	&most_chnl_attr_set_direction.attr,
+	&most_chnl_attr_set_datatype.attr,
+	&most_chnl_attr_set_subbuffer_size.attr,
+	&most_chnl_attr_set_packets_per_xact.attr,
+	&most_chnl_attr_channel_starving.attr,
+	NULL,
+};
+
+static struct kobj_type most_channel_ktype = {
+	.sysfs_ops = &most_channel_sysfs_ops,
+	.release = most_channel_release,
+	.default_attrs = most_channel_def_attrs,
+};
+
+static struct kset *most_channel_kset;
+
+/**
+ * create_most_c_obj - allocates a channel object
+ * @name: name of the channel object
+ * @parent: parent kobject
+ *
+ * This create a channel object and registers it with sysfs.
+ * Returns a pointer to the object or NULL when something went wrong.
+ */
+static struct most_c_obj *
+create_most_c_obj(const char *name, struct kobject *parent)
+{
+	struct most_c_obj *c;
+	int retval;
+
+	c = kzalloc(sizeof(*c), GFP_KERNEL);
+	if (!c)
+		return NULL;
+	c->kobj.kset = most_channel_kset;
+	retval = kobject_init_and_add(&c->kobj, &most_channel_ktype, parent,
+				      "%s", name);
+	if (retval) {
+		kobject_put(&c->kobj);
+		return NULL;
+	}
+	kobject_uevent(&c->kobj, KOBJ_ADD);
+	return c;
+}
+
+/*		     ___	       ___
+ *		     ___I N S T A N C E___
+ */
+#define MOST_INST_ATTR(_name, _mode, _show, _store) \
+		struct most_inst_attribute most_inst_attr_##_name = \
+		__ATTR(_name, _mode, _show, _store)
+
+static struct list_head instance_list;
+
+/**
+ * struct most_inst_attribute - to access the attributes of instance object
+ * @attr: attributes of an instance
+ * @show: pointer to the show function
+ * @store: pointer to the store function
+ */
+struct most_inst_attribute {
+	struct attribute attr;
+	ssize_t (*show)(struct most_inst_obj *d,
+			struct most_inst_attribute *attr,
+			char *buf);
+	ssize_t (*store)(struct most_inst_obj *d,
+			 struct most_inst_attribute *attr,
+			 const char *buf,
+			 size_t count);
+};
+
+#define to_instance_attr(a) \
+	container_of(a, struct most_inst_attribute, attr)
+
+/**
+ * instance_attr_show - show function for an instance object
+ * @kobj: pointer to kobject
+ * @attr: pointer to attribute struct
+ * @buf: buffer
+ */
+static ssize_t instance_attr_show(struct kobject *kobj,
+				  struct attribute *attr,
+				  char *buf)
+{
+	struct most_inst_attribute *instance_attr;
+	struct most_inst_obj *instance_obj;
+
+	instance_attr = to_instance_attr(attr);
+	instance_obj = to_inst_obj(kobj);
+
+	if (!instance_attr->show)
+		return -EIO;
+
+	return instance_attr->show(instance_obj, instance_attr, buf);
+}
+
+/**
+ * instance_attr_store - store function for an instance object
+ * @kobj: pointer to kobject
+ * @attr: pointer to attribute struct
+ * @buf: buffer
+ * @len: length of buffer
+ */
+static ssize_t instance_attr_store(struct kobject *kobj,
+				   struct attribute *attr,
+				   const char *buf,
+				   size_t len)
+{
+	struct most_inst_attribute *instance_attr;
+	struct most_inst_obj *instance_obj;
+
+	instance_attr = to_instance_attr(attr);
+	instance_obj = to_inst_obj(kobj);
+
+	if (!instance_attr->store)
+		return -EIO;
+
+	return instance_attr->store(instance_obj, instance_attr, buf, len);
+}
+
+static const struct sysfs_ops most_inst_sysfs_ops = {
+	.show = instance_attr_show,
+	.store = instance_attr_store,
+};
+
+/**
+ * most_inst_release - release function for instance object
+ * @kobj: pointer to instance's kobject
+ *
+ * This frees the allocated memory for the instance object
+ */
+static void most_inst_release(struct kobject *kobj)
+{
+	struct most_inst_obj *inst = to_inst_obj(kobj);
+
+	kfree(inst);
+}
+
+static ssize_t show_description(struct most_inst_obj *instance_obj,
+				struct most_inst_attribute *attr,
+				char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%s\n",
+			instance_obj->iface->description);
+}
+
+static ssize_t show_interface(struct most_inst_obj *instance_obj,
+			      struct most_inst_attribute *attr,
+			      char *buf)
+{
+	switch (instance_obj->iface->interface) {
+	case ITYPE_LOOPBACK:
+		return snprintf(buf, PAGE_SIZE, "loopback\n");
+	case ITYPE_I2C:
+		return snprintf(buf, PAGE_SIZE, "i2c\n");
+	case ITYPE_I2S:
+		return snprintf(buf, PAGE_SIZE, "i2s\n");
+	case ITYPE_TSI:
+		return snprintf(buf, PAGE_SIZE, "tsi\n");
+	case ITYPE_HBI:
+		return snprintf(buf, PAGE_SIZE, "hbi\n");
+	case ITYPE_MEDIALB_DIM:
+		return snprintf(buf, PAGE_SIZE, "mlb_dim\n");
+	case ITYPE_MEDIALB_DIM2:
+		return snprintf(buf, PAGE_SIZE, "mlb_dim2\n");
+	case ITYPE_USB:
+		return snprintf(buf, PAGE_SIZE, "usb\n");
+	case ITYPE_PCIE:
+		return snprintf(buf, PAGE_SIZE, "pcie\n");
+	}
+	return snprintf(buf, PAGE_SIZE, "unknown\n");
+}
+
+#define create_inst_attribute(value) \
+	static MOST_INST_ATTR(value, S_IRUGO, show_##value, NULL)
+
+create_inst_attribute(description);
+create_inst_attribute(interface);
+
+static struct attribute *most_inst_def_attrs[] = {
+	&most_inst_attr_description.attr,
+	&most_inst_attr_interface.attr,
+	NULL,
+};
+
+static struct kobj_type most_inst_ktype = {
+	.sysfs_ops = &most_inst_sysfs_ops,
+	.release = most_inst_release,
+	.default_attrs = most_inst_def_attrs,
+};
+
+static struct kset *most_inst_kset;
+
+/**
+ * create_most_inst_obj - creates an instance object
+ * @name: name of the object to be created
+ *
+ * This allocates memory for an instance structure, assigns the proper kset
+ * and registers it with sysfs.
+ *
+ * Returns a pointer to the instance object or NULL when something went wrong.
+ */
+static struct most_inst_obj *create_most_inst_obj(const char *name)
+{
+	struct most_inst_obj *inst;
+	int retval;
+
+	inst = kzalloc(sizeof(*inst), GFP_KERNEL);
+	if (!inst)
+		return NULL;
+	inst->kobj.kset = most_inst_kset;
+	retval = kobject_init_and_add(&inst->kobj, &most_inst_ktype, NULL,
+				      "%s", name);
+	if (retval) {
+		kobject_put(&inst->kobj);
+		return NULL;
+	}
+	kobject_uevent(&inst->kobj, KOBJ_ADD);
+	return inst;
+}
+
+/**
+ * destroy_most_inst_obj - MOST instance release function
+ * @inst: pointer to the instance object
+ *
+ * This decrements the reference counter of the instance object.
+ * If the reference count turns zero, its release function is called
+ */
+static void destroy_most_inst_obj(struct most_inst_obj *inst)
+{
+	struct most_c_obj *c, *tmp;
+
+	list_for_each_entry_safe(c, tmp, &inst->channel_list, list) {
+		flush_trash_fifo(c);
+		flush_channel_fifos(c);
+		kobject_put(&c->kobj);
+	}
+	kobject_put(&inst->kobj);
+}
+
+/*		     ___     ___
+ *		     ___A I M___
+ */
+struct most_aim_obj {
+	struct kobject kobj;
+	struct list_head list;
+	struct most_aim *driver;
+	char add_link[STRING_SIZE];
+	char remove_link[STRING_SIZE];
+};
+
+#define to_aim_obj(d) container_of(d, struct most_aim_obj, kobj)
+
+static struct list_head aim_list;
+
+/**
+ * struct most_aim_attribute - to access the attributes of AIM object
+ * @attr: attributes of an AIM
+ * @show: pointer to the show function
+ * @store: pointer to the store function
+ */
+struct most_aim_attribute {
+	struct attribute attr;
+	ssize_t (*show)(struct most_aim_obj *d,
+			struct most_aim_attribute *attr,
+			char *buf);
+	ssize_t (*store)(struct most_aim_obj *d,
+			 struct most_aim_attribute *attr,
+			 const char *buf,
+			 size_t count);
+};
+
+#define to_aim_attr(a) container_of(a, struct most_aim_attribute, attr)
+
+/**
+ * aim_attr_show - show function of an AIM object
+ * @kobj: pointer to kobject
+ * @attr: pointer to attribute struct
+ * @buf: buffer
+ */
+static ssize_t aim_attr_show(struct kobject *kobj,
+			     struct attribute *attr,
+			     char *buf)
+{
+	struct most_aim_attribute *aim_attr;
+	struct most_aim_obj *aim_obj;
+
+	aim_attr = to_aim_attr(attr);
+	aim_obj = to_aim_obj(kobj);
+
+	if (!aim_attr->show)
+		return -EIO;
+
+	return aim_attr->show(aim_obj, aim_attr, buf);
+}
+
+/**
+ * aim_attr_store - store function of an AIM object
+ * @kobj: pointer to kobject
+ * @attr: pointer to attribute struct
+ * @buf: buffer
+ * @len: length of buffer
+ */
+static ssize_t aim_attr_store(struct kobject *kobj,
+			      struct attribute *attr,
+			      const char *buf,
+			      size_t len)
+{
+	struct most_aim_attribute *aim_attr;
+	struct most_aim_obj *aim_obj;
+
+	aim_attr = to_aim_attr(attr);
+	aim_obj = to_aim_obj(kobj);
+
+	if (!aim_attr->store)
+		return -EIO;
+	return aim_attr->store(aim_obj, aim_attr, buf, len);
+}
+
+static const struct sysfs_ops most_aim_sysfs_ops = {
+	.show = aim_attr_show,
+	.store = aim_attr_store,
+};
+
+/**
+ * most_aim_release - AIM release function
+ * @kobj: pointer to AIM's kobject
+ */
+static void most_aim_release(struct kobject *kobj)
+{
+	struct most_aim_obj *aim_obj = to_aim_obj(kobj);
+
+	kfree(aim_obj);
+}
+
+static ssize_t show_add_link(struct most_aim_obj *aim_obj,
+			     struct most_aim_attribute *attr,
+			     char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%s\n", aim_obj->add_link);
+}
+
+/**
+ * split_string - parses and changes string in the buffer buf and
+ * splits it into two mandatory and one optional substrings.
+ *
+ * @buf: complete string from attribute 'add_channel'
+ * @a: address of pointer to 1st substring (=instance name)
+ * @b: address of pointer to 2nd substring (=channel name)
+ * @c: optional address of pointer to 3rd substring (=user defined name)
+ *
+ * Examples:
+ *
+ * Input: "mdev0:ch0@ep_81:my_channel\n" or
+ *        "mdev0:ch0@ep_81:my_channel"
+ *
+ * Output: *a -> "mdev0", *b -> "ch0@ep_81", *c -> "my_channel"
+ *
+ * Input: "mdev0:ch0@ep_81\n"
+ * Output: *a -> "mdev0", *b -> "ch0@ep_81", *c -> ""
+ *
+ * Input: "mdev0:ch0@ep_81"
+ * Output: *a -> "mdev0", *b -> "ch0@ep_81", *c == NULL
+ */
+static int split_string(char *buf, char **a, char **b, char **c)
+{
+	*a = strsep(&buf, ":");
+	if (!*a)
+		return -EIO;
+
+	*b = strsep(&buf, ":\n");
+	if (!*b)
+		return -EIO;
+
+	if (c)
+		*c = strsep(&buf, ":\n");
+
+	return 0;
+}
+
+/**
+ * get_channel_by_name - get pointer to channel object
+ * @mdev: name of the device instance
+ * @mdev_ch: name of the respective channel
+ *
+ * This retrieves the pointer to a channel object.
+ */
+static struct
+most_c_obj *get_channel_by_name(char *mdev, char *mdev_ch)
+{
+	struct most_c_obj *c, *tmp;
+	struct most_inst_obj *i, *i_tmp;
+	int found = 0;
+
+	list_for_each_entry_safe(i, i_tmp, &instance_list, list) {
+		if (!strcmp(kobject_name(&i->kobj), mdev)) {
+			found++;
+			break;
+		}
+	}
+	if (unlikely(!found))
+		return ERR_PTR(-EIO);
+
+	list_for_each_entry_safe(c, tmp, &i->channel_list, list) {
+		if (!strcmp(kobject_name(&c->kobj), mdev_ch)) {
+			found++;
+			break;
+		}
+	}
+	if (unlikely(found < 2))
+		return ERR_PTR(-EIO);
+	return c;
+}
+
+/**
+ * store_add_link - store() function for add_link attribute
+ * @aim_obj: pointer to AIM object
+ * @attr: its attributes
+ * @buf: buffer
+ * @len: buffer length
+ *
+ * This parses the string given by buf and splits it into
+ * three substrings. Note: third substring is optional. In case a cdev
+ * AIM is loaded the optional 3rd substring will make up the name of
+ * device node in the /dev directory. If omitted, the device node will
+ * inherit the channel's name within sysfs.
+ *
+ * Searches for a pair of device and channel and probes the AIM
+ *
+ * Example:
+ * (1) echo -n -e "mdev0:ch0@ep_81:my_rxchannel\n" >add_link
+ * (2) echo -n -e "mdev0:ch0@ep_81\n" >add_link
+ *
+ * (1) would create the device node /dev/my_rxchannel
+ * (2) would create the device node /dev/mdev0-ch0@ep_81
+ */
+static ssize_t store_add_link(struct most_aim_obj *aim_obj,
+			      struct most_aim_attribute *attr,
+			      const char *buf,
+			      size_t len)
+{
+	struct most_c_obj *c;
+	struct most_aim **aim_ptr;
+	char buffer[STRING_SIZE];
+	char *mdev;
+	char *mdev_ch;
+	char *mdev_devnod;
+	char devnod_buf[STRING_SIZE];
+	int ret;
+	size_t max_len = min_t(size_t, len + 1, STRING_SIZE);
+
+	strlcpy(buffer, buf, max_len);
+	strlcpy(aim_obj->add_link, buf, max_len);
+
+	ret = split_string(buffer, &mdev, &mdev_ch, &mdev_devnod);
+	if (ret)
+		return ret;
+
+	if (!mdev_devnod || *mdev_devnod == 0) {
+		snprintf(devnod_buf, sizeof(devnod_buf), "%s-%s", mdev,
+			 mdev_ch);
+		mdev_devnod = devnod_buf;
+	}
+
+	c = get_channel_by_name(mdev, mdev_ch);
+	if (IS_ERR(c))
+		return -ENODEV;
+
+	if (!c->aim0.ptr)
+		aim_ptr = &c->aim0.ptr;
+	else if (!c->aim1.ptr)
+		aim_ptr = &c->aim1.ptr;
+	else
+		return -ENOSPC;
+
+	*aim_ptr = aim_obj->driver;
+	ret = aim_obj->driver->probe_channel(c->iface, c->channel_id,
+					     &c->cfg, &c->kobj, mdev_devnod);
+	if (ret) {
+		*aim_ptr = NULL;
+		return ret;
+	}
+
+	return len;
+}
+
+static struct most_aim_attribute most_aim_attr_add_link =
+	__ATTR(add_link, S_IRUGO | S_IWUSR, show_add_link, store_add_link);
+
+static ssize_t show_remove_link(struct most_aim_obj *aim_obj,
+				struct most_aim_attribute *attr,
+				char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%s\n", aim_obj->remove_link);
+}
+
+/**
+ * store_remove_link - store function for remove_link attribute
+ * @aim_obj: pointer to AIM object
+ * @attr: its attributes
+ * @buf: buffer
+ * @len: buffer length
+ *
+ * Example:
+ * echo -n -e "mdev0:ch0@ep_81\n" >remove_link
+ */
+static ssize_t store_remove_link(struct most_aim_obj *aim_obj,
+				 struct most_aim_attribute *attr,
+				 const char *buf,
+				 size_t len)
+{
+	struct most_c_obj *c;
+	char buffer[STRING_SIZE];
+	char *mdev;
+	char *mdev_ch;
+	int ret;
+	size_t max_len = min_t(size_t, len + 1, STRING_SIZE);
+
+	strlcpy(buffer, buf, max_len);
+	strlcpy(aim_obj->remove_link, buf, max_len);
+	ret = split_string(buffer, &mdev, &mdev_ch, NULL);
+	if (ret)
+		return ret;
+
+	c = get_channel_by_name(mdev, mdev_ch);
+	if (IS_ERR(c))
+		return -ENODEV;
+
+	if (aim_obj->driver->disconnect_channel(c->iface, c->channel_id))
+		return -EIO;
+	if (c->aim0.ptr == aim_obj->driver)
+		c->aim0.ptr = NULL;
+	if (c->aim1.ptr == aim_obj->driver)
+		c->aim1.ptr = NULL;
+	return len;
+}
+
+static struct most_aim_attribute most_aim_attr_remove_link =
+	__ATTR(remove_link, S_IRUGO | S_IWUSR, show_remove_link,
+	       store_remove_link);
+
+static struct attribute *most_aim_def_attrs[] = {
+	&most_aim_attr_add_link.attr,
+	&most_aim_attr_remove_link.attr,
+	NULL,
+};
+
+static struct kobj_type most_aim_ktype = {
+	.sysfs_ops = &most_aim_sysfs_ops,
+	.release = most_aim_release,
+	.default_attrs = most_aim_def_attrs,
+};
+
+static struct kset *most_aim_kset;
+
+/**
+ * create_most_aim_obj - creates an AIM object
+ * @name: name of the AIM
+ *
+ * This creates an AIM object assigns the proper kset and registers
+ * it with sysfs.
+ * Returns a pointer to the object or NULL if something went wrong.
+ */
+static struct most_aim_obj *create_most_aim_obj(const char *name)
+{
+	struct most_aim_obj *most_aim;
+	int retval;
+
+	most_aim = kzalloc(sizeof(*most_aim), GFP_KERNEL);
+	if (!most_aim)
+		return NULL;
+	most_aim->kobj.kset = most_aim_kset;
+	retval = kobject_init_and_add(&most_aim->kobj, &most_aim_ktype,
+				      NULL, "%s", name);
+	if (retval) {
+		kobject_put(&most_aim->kobj);
+		return NULL;
+	}
+	kobject_uevent(&most_aim->kobj, KOBJ_ADD);
+	return most_aim;
+}
+
+/**
+ * destroy_most_aim_obj - AIM release function
+ * @p: pointer to AIM object
+ *
+ * This decrements the reference counter of the AIM object. If the
+ * reference count turns zero, its release function will be called.
+ */
+static void destroy_most_aim_obj(struct most_aim_obj *p)
+{
+	kobject_put(&p->kobj);
+}
+
+/*		     ___       ___
+ *		     ___C O R E___
+ */
+
+/**
+ * Instantiation of the MOST bus
+ */
+static struct bus_type most_bus = {
+	.name = "most",
+};
+
+/**
+ * Instantiation of the core driver
+ */
+static struct device_driver mostcore = {
+	.name = "mostcore",
+	.bus = &most_bus,
+};
+
+static inline void trash_mbo(struct mbo *mbo)
+{
+	unsigned long flags;
+	struct most_c_obj *c = mbo->context;
+
+	spin_lock_irqsave(&c->fifo_lock, flags);
+	list_add(&mbo->list, &c->trash_fifo);
+	spin_unlock_irqrestore(&c->fifo_lock, flags);
+}
+
+static bool hdm_mbo_ready(struct most_c_obj *c)
+{
+	bool empty;
+
+	if (c->enqueue_halt)
+		return false;
+
+	spin_lock_irq(&c->fifo_lock);
+	empty = list_empty(&c->halt_fifo);
+	spin_unlock_irq(&c->fifo_lock);
+
+	return !empty;
+}
+
+static void nq_hdm_mbo(struct mbo *mbo)
+{
+	unsigned long flags;
+	struct most_c_obj *c = mbo->context;
+
+	spin_lock_irqsave(&c->fifo_lock, flags);
+	list_add_tail(&mbo->list, &c->halt_fifo);
+	spin_unlock_irqrestore(&c->fifo_lock, flags);
+	wake_up_interruptible(&c->hdm_fifo_wq);
+}
+
+static int hdm_enqueue_thread(void *data)
+{
+	struct most_c_obj *c = data;
+	struct mbo *mbo;
+	int ret;
+	typeof(c->iface->enqueue) enqueue = c->iface->enqueue;
+
+	while (likely(!kthread_should_stop())) {
+		wait_event_interruptible(c->hdm_fifo_wq,
+					 hdm_mbo_ready(c) ||
+					 kthread_should_stop());
+
+		mutex_lock(&c->nq_mutex);
+		spin_lock_irq(&c->fifo_lock);
+		if (unlikely(c->enqueue_halt || list_empty(&c->halt_fifo))) {
+			spin_unlock_irq(&c->fifo_lock);
+			mutex_unlock(&c->nq_mutex);
+			continue;
+		}
+
+		mbo = list_pop_mbo(&c->halt_fifo);
+		spin_unlock_irq(&c->fifo_lock);
+
+		if (c->cfg.direction == MOST_CH_RX)
+			mbo->buffer_length = c->cfg.buffer_size;
+
+		ret = enqueue(mbo->ifp, mbo->hdm_channel_id, mbo);
+		mutex_unlock(&c->nq_mutex);
+
+		if (unlikely(ret)) {
+			pr_err("hdm enqueue failed\n");
+			nq_hdm_mbo(mbo);
+			c->hdm_enqueue_task = NULL;
+			return 0;
+		}
+	}
+
+	return 0;
+}
+
+static int run_enqueue_thread(struct most_c_obj *c, int channel_id)
+{
+	struct task_struct *task =
+		kthread_run(hdm_enqueue_thread, c, "hdm_fifo_%d",
+			    channel_id);
+
+	if (IS_ERR(task))
+		return PTR_ERR(task);
+
+	c->hdm_enqueue_task = task;
+	return 0;
+}
+
+/**
+ * arm_mbo - recycle MBO for further usage
+ * @mbo: buffer object
+ *
+ * This puts an MBO back to the list to have it ready for up coming
+ * tx transactions.
+ *
+ * In case the MBO belongs to a channel that recently has been
+ * poisoned, the MBO is scheduled to be trashed.
+ * Calls the completion handler of an attached AIM.
+ */
+static void arm_mbo(struct mbo *mbo)
+{
+	unsigned long flags;
+	struct most_c_obj *c;
+
+	BUG_ON((!mbo) || (!mbo->context));
+	c = mbo->context;
+
+	if (c->is_poisoned) {
+		trash_mbo(mbo);
+		return;
+	}
+
+	spin_lock_irqsave(&c->fifo_lock, flags);
+	++*mbo->num_buffers_ptr;
+	list_add_tail(&mbo->list, &c->fifo);
+	spin_unlock_irqrestore(&c->fifo_lock, flags);
+
+	if (c->aim0.refs && c->aim0.ptr->tx_completion)
+		c->aim0.ptr->tx_completion(c->iface, c->channel_id);
+
+	if (c->aim1.refs && c->aim1.ptr->tx_completion)
+		c->aim1.ptr->tx_completion(c->iface, c->channel_id);
+}
+
+/**
+ * arm_mbo_chain - helper function that arms an MBO chain for the HDM
+ * @c: pointer to interface channel
+ * @dir: direction of the channel
+ * @compl: pointer to completion function
+ *
+ * This allocates buffer objects including the containing DMA coherent
+ * buffer and puts them in the fifo.
+ * Buffers of Rx channels are put in the kthread fifo, hence immediately
+ * submitted to the HDM.
+ *
+ * Returns the number of allocated and enqueued MBOs.
+ */
+static int arm_mbo_chain(struct most_c_obj *c, int dir,
+			 void (*compl)(struct mbo *))
+{
+	unsigned int i;
+	int retval;
+	struct mbo *mbo;
+	u32 coherent_buf_size = c->cfg.buffer_size + c->cfg.extra_len;
+
+	atomic_set(&c->mbo_nq_level, 0);
+
+	for (i = 0; i < c->cfg.num_buffers; i++) {
+		mbo = kzalloc(sizeof(*mbo), GFP_KERNEL);
+		if (!mbo) {
+			retval = i;
+			goto _exit;
+		}
+		mbo->context = c;
+		mbo->ifp = c->iface;
+		mbo->hdm_channel_id = c->channel_id;
+		mbo->virt_address = dma_alloc_coherent(NULL,
+						       coherent_buf_size,
+						       &mbo->bus_address,
+						       GFP_KERNEL);
+		if (!mbo->virt_address) {
+			pr_info("WARN: No DMA coherent buffer.\n");
+			retval = i;
+			goto _error1;
+		}
+		mbo->complete = compl;
+		mbo->num_buffers_ptr = &dummy_num_buffers;
+		if (dir == MOST_CH_RX) {
+			nq_hdm_mbo(mbo);
+			atomic_inc(&c->mbo_nq_level);
+		} else {
+			arm_mbo(mbo);
+		}
+	}
+	return i;
+
+_error1:
+	kfree(mbo);
+_exit:
+	return retval;
+}
+
+/**
+ * most_submit_mbo - submits an MBO to fifo
+ * @mbo: pointer to the MBO
+ *
+ */
+int most_submit_mbo(struct mbo *mbo)
+{
+	if (unlikely((!mbo) || (!mbo->context))) {
+		pr_err("Bad MBO or missing channel reference\n");
+		return -EINVAL;
+	}
+
+	nq_hdm_mbo(mbo);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(most_submit_mbo);
+
+/**
+ * most_write_completion - write completion handler
+ * @mbo: pointer to MBO
+ *
+ * This recycles the MBO for further usage. In case the channel has been
+ * poisoned, the MBO is scheduled to be trashed.
+ */
+static void most_write_completion(struct mbo *mbo)
+{
+	struct most_c_obj *c;
+
+	BUG_ON((!mbo) || (!mbo->context));
+
+	c = mbo->context;
+	if (mbo->status == MBO_E_INVAL)
+		pr_info("WARN: Tx MBO status: invalid\n");
+	if (unlikely(c->is_poisoned || (mbo->status == MBO_E_CLOSE)))
+		trash_mbo(mbo);
+	else
+		arm_mbo(mbo);
+}
+
+/**
+ * get_channel_by_iface - get pointer to channel object
+ * @iface: pointer to interface instance
+ * @id: channel ID
+ *
+ * This retrieves a pointer to a channel of the given interface and channel ID.
+ */
+static struct
+most_c_obj *get_channel_by_iface(struct most_interface *iface, int id)
+{
+	struct most_inst_obj *i;
+
+	if (unlikely(!iface)) {
+		pr_err("Bad interface\n");
+		return NULL;
+	}
+	if (unlikely((id < 0) || (id >= iface->num_channels))) {
+		pr_err("Channel index (%d) out of range\n", id);
+		return NULL;
+	}
+	i = iface->priv;
+	if (unlikely(!i)) {
+		pr_err("interface is not registered\n");
+		return NULL;
+	}
+	return i->channel[id];
+}
+
+int channel_has_mbo(struct most_interface *iface, int id, struct most_aim *aim)
+{
+	struct most_c_obj *c = get_channel_by_iface(iface, id);
+	unsigned long flags;
+	int empty;
+
+	if (unlikely(!c))
+		return -EINVAL;
+
+	if (c->aim0.refs && c->aim1.refs &&
+	    ((aim == c->aim0.ptr && c->aim0.num_buffers <= 0) ||
+	     (aim == c->aim1.ptr && c->aim1.num_buffers <= 0)))
+		return 0;
+
+	spin_lock_irqsave(&c->fifo_lock, flags);
+	empty = list_empty(&c->fifo);
+	spin_unlock_irqrestore(&c->fifo_lock, flags);
+	return !empty;
+}
+EXPORT_SYMBOL_GPL(channel_has_mbo);
+
+/**
+ * most_get_mbo - get pointer to an MBO of pool
+ * @iface: pointer to interface instance
+ * @id: channel ID
+ *
+ * This attempts to get a free buffer out of the channel fifo.
+ * Returns a pointer to MBO on success or NULL otherwise.
+ */
+struct mbo *most_get_mbo(struct most_interface *iface, int id,
+			 struct most_aim *aim)
+{
+	struct mbo *mbo;
+	struct most_c_obj *c;
+	unsigned long flags;
+	int *num_buffers_ptr;
+
+	c = get_channel_by_iface(iface, id);
+	if (unlikely(!c))
+		return NULL;
+
+	if (c->aim0.refs && c->aim1.refs &&
+	    ((aim == c->aim0.ptr && c->aim0.num_buffers <= 0) ||
+	     (aim == c->aim1.ptr && c->aim1.num_buffers <= 0)))
+		return NULL;
+
+	if (aim == c->aim0.ptr)
+		num_buffers_ptr = &c->aim0.num_buffers;
+	else if (aim == c->aim1.ptr)
+		num_buffers_ptr = &c->aim1.num_buffers;
+	else
+		num_buffers_ptr = &dummy_num_buffers;
+
+	spin_lock_irqsave(&c->fifo_lock, flags);
+	if (list_empty(&c->fifo)) {
+		spin_unlock_irqrestore(&c->fifo_lock, flags);
+		return NULL;
+	}
+	mbo = list_pop_mbo(&c->fifo);
+	--*num_buffers_ptr;
+	spin_unlock_irqrestore(&c->fifo_lock, flags);
+
+	mbo->num_buffers_ptr = num_buffers_ptr;
+	mbo->buffer_length = c->cfg.buffer_size;
+	return mbo;
+}
+EXPORT_SYMBOL_GPL(most_get_mbo);
+
+/**
+ * most_put_mbo - return buffer to pool
+ * @mbo: buffer object
+ */
+void most_put_mbo(struct mbo *mbo)
+{
+	struct most_c_obj *c = mbo->context;
+
+	if (c->cfg.direction == MOST_CH_TX) {
+		arm_mbo(mbo);
+		return;
+	}
+	nq_hdm_mbo(mbo);
+	atomic_inc(&c->mbo_nq_level);
+}
+EXPORT_SYMBOL_GPL(most_put_mbo);
+
+/**
+ * most_read_completion - read completion handler
+ * @mbo: pointer to MBO
+ *
+ * This function is called by the HDM when data has been received from the
+ * hardware and copied to the buffer of the MBO.
+ *
+ * In case the channel has been poisoned it puts the buffer in the trash queue.
+ * Otherwise, it passes the buffer to an AIM for further processing.
+ */
+static void most_read_completion(struct mbo *mbo)
+{
+	struct most_c_obj *c = mbo->context;
+
+	if (unlikely(c->is_poisoned || (mbo->status == MBO_E_CLOSE))) {
+		trash_mbo(mbo);
+		return;
+	}
+
+	if (mbo->status == MBO_E_INVAL) {
+		nq_hdm_mbo(mbo);
+		atomic_inc(&c->mbo_nq_level);
+		return;
+	}
+
+	if (atomic_sub_and_test(1, &c->mbo_nq_level))
+		c->is_starving = 1;
+
+	if (c->aim0.refs && c->aim0.ptr->rx_completion &&
+	    c->aim0.ptr->rx_completion(mbo) == 0)
+		return;
+
+	if (c->aim1.refs && c->aim1.ptr->rx_completion &&
+	    c->aim1.ptr->rx_completion(mbo) == 0)
+		return;
+
+	most_put_mbo(mbo);
+}
+
+/**
+ * most_start_channel - prepares a channel for communication
+ * @iface: pointer to interface instance
+ * @id: channel ID
+ *
+ * This prepares the channel for usage. Cross-checks whether the
+ * channel's been properly configured.
+ *
+ * Returns 0 on success or error code otherwise.
+ */
+int most_start_channel(struct most_interface *iface, int id,
+		       struct most_aim *aim)
+{
+	int num_buffer;
+	int ret;
+	struct most_c_obj *c = get_channel_by_iface(iface, id);
+
+	if (unlikely(!c))
+		return -EINVAL;
+
+	mutex_lock(&c->start_mutex);
+	if (c->aim0.refs + c->aim1.refs > 0)
+		goto out; /* already started by other aim */
+
+	if (!try_module_get(iface->mod)) {
+		pr_info("failed to acquire HDM lock\n");
+		mutex_unlock(&c->start_mutex);
+		return -ENOLCK;
+	}
+
+	c->cfg.extra_len = 0;
+	if (c->iface->configure(c->iface, c->channel_id, &c->cfg)) {
+		pr_info("channel configuration failed. Go check settings...\n");
+		ret = -EINVAL;
+		goto error;
+	}
+
+	init_waitqueue_head(&c->hdm_fifo_wq);
+
+	if (c->cfg.direction == MOST_CH_RX)
+		num_buffer = arm_mbo_chain(c, c->cfg.direction,
+					   most_read_completion);
+	else
+		num_buffer = arm_mbo_chain(c, c->cfg.direction,
+					   most_write_completion);
+	if (unlikely(!num_buffer)) {
+		pr_info("failed to allocate memory\n");
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	ret = run_enqueue_thread(c, id);
+	if (ret)
+		goto error;
+
+	c->is_starving = 0;
+	c->aim0.num_buffers = c->cfg.num_buffers / 2;
+	c->aim1.num_buffers = c->cfg.num_buffers - c->aim0.num_buffers;
+	atomic_set(&c->mbo_ref, num_buffer);
+
+out:
+	if (aim == c->aim0.ptr)
+		c->aim0.refs++;
+	if (aim == c->aim1.ptr)
+		c->aim1.refs++;
+	mutex_unlock(&c->start_mutex);
+	return 0;
+
+error:
+	module_put(iface->mod);
+	mutex_unlock(&c->start_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(most_start_channel);
+
+/**
+ * most_stop_channel - stops a running channel
+ * @iface: pointer to interface instance
+ * @id: channel ID
+ */
+int most_stop_channel(struct most_interface *iface, int id,
+		      struct most_aim *aim)
+{
+	struct most_c_obj *c;
+
+	if (unlikely((!iface) || (id >= iface->num_channels) || (id < 0))) {
+		pr_err("Bad interface or index out of range\n");
+		return -EINVAL;
+	}
+	c = get_channel_by_iface(iface, id);
+	if (unlikely(!c))
+		return -EINVAL;
+
+	mutex_lock(&c->start_mutex);
+	if (c->aim0.refs + c->aim1.refs >= 2)
+		goto out;
+
+	if (c->hdm_enqueue_task)
+		kthread_stop(c->hdm_enqueue_task);
+	c->hdm_enqueue_task = NULL;
+
+	if (iface->mod)
+		module_put(iface->mod);
+
+	c->is_poisoned = true;
+	if (c->iface->poison_channel(c->iface, c->channel_id)) {
+		pr_err("Cannot stop channel %d of mdev %s\n", c->channel_id,
+		       c->iface->description);
+		mutex_unlock(&c->start_mutex);
+		return -EAGAIN;
+	}
+	flush_trash_fifo(c);
+	flush_channel_fifos(c);
+
+#ifdef CMPL_INTERRUPTIBLE
+	if (wait_for_completion_interruptible(&c->cleanup)) {
+		pr_info("Interrupted while clean up ch %d\n", c->channel_id);
+		mutex_unlock(&c->start_mutex);
+		return -EINTR;
+	}
+#else
+	wait_for_completion(&c->cleanup);
+#endif
+	c->is_poisoned = false;
+
+out:
+	if (aim == c->aim0.ptr)
+		c->aim0.refs--;
+	if (aim == c->aim1.ptr)
+		c->aim1.refs--;
+	mutex_unlock(&c->start_mutex);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(most_stop_channel);
+
+/**
+ * most_register_aim - registers an AIM (driver) with the core
+ * @aim: instance of AIM to be registered
+ */
+int most_register_aim(struct most_aim *aim)
+{
+	struct most_aim_obj *aim_obj;
+
+	if (!aim) {
+		pr_err("Bad driver\n");
+		return -EINVAL;
+	}
+	aim_obj = create_most_aim_obj(aim->name);
+	if (!aim_obj) {
+		pr_info("failed to alloc driver object\n");
+		return -ENOMEM;
+	}
+	aim_obj->driver = aim;
+	aim->context = aim_obj;
+	pr_info("registered new application interfacing module %s\n",
+		aim->name);
+	list_add_tail(&aim_obj->list, &aim_list);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(most_register_aim);
+
+/**
+ * most_deregister_aim - deregisters an AIM (driver) with the core
+ * @aim: AIM to be removed
+ */
+int most_deregister_aim(struct most_aim *aim)
+{
+	struct most_aim_obj *aim_obj;
+	struct most_c_obj *c, *tmp;
+	struct most_inst_obj *i, *i_tmp;
+
+	if (!aim) {
+		pr_err("Bad driver\n");
+		return -EINVAL;
+	}
+
+	aim_obj = aim->context;
+	if (!aim_obj) {
+		pr_info("driver not registered.\n");
+		return -EINVAL;
+	}
+	list_for_each_entry_safe(i, i_tmp, &instance_list, list) {
+		list_for_each_entry_safe(c, tmp, &i->channel_list, list) {
+			if (c->aim0.ptr == aim || c->aim1.ptr == aim)
+				aim->disconnect_channel(
+					c->iface, c->channel_id);
+			if (c->aim0.ptr == aim)
+				c->aim0.ptr = NULL;
+			if (c->aim1.ptr == aim)
+				c->aim1.ptr = NULL;
+		}
+	}
+	list_del(&aim_obj->list);
+	destroy_most_aim_obj(aim_obj);
+	pr_info("deregistering application interfacing module %s\n", aim->name);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(most_deregister_aim);
+
+/**
+ * most_register_interface - registers an interface with core
+ * @iface: pointer to the instance of the interface description.
+ *
+ * Allocates and initializes a new interface instance and all of its channels.
+ * Returns a pointer to kobject or an error pointer.
+ */
+struct kobject *most_register_interface(struct most_interface *iface)
+{
+	unsigned int i;
+	int id;
+	char name[STRING_SIZE];
+	char channel_name[STRING_SIZE];
+	struct most_c_obj *c;
+	struct most_inst_obj *inst;
+
+	if (!iface || !iface->enqueue || !iface->configure ||
+	    !iface->poison_channel || (iface->num_channels > MAX_CHANNELS)) {
+		pr_err("Bad interface or channel overflow\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	id = ida_simple_get(&mdev_id, 0, 0, GFP_KERNEL);
+	if (id < 0) {
+		pr_info("Failed to alloc mdev ID\n");
+		return ERR_PTR(id);
+	}
+	snprintf(name, STRING_SIZE, "mdev%d", id);
+
+	inst = create_most_inst_obj(name);
+	if (!inst) {
+		pr_info("Failed to allocate interface instance\n");
+		ida_simple_remove(&mdev_id, id);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	iface->priv = inst;
+	INIT_LIST_HEAD(&inst->channel_list);
+	inst->iface = iface;
+	inst->dev_id = id;
+	list_add_tail(&inst->list, &instance_list);
+
+	for (i = 0; i < iface->num_channels; i++) {
+		const char *name_suffix = iface->channel_vector[i].name_suffix;
+
+		if (!name_suffix)
+			snprintf(channel_name, STRING_SIZE, "ch%d", i);
+		else if (name_suffix[0] == '@')
+			snprintf(channel_name, STRING_SIZE, "ch%d%s", i,
+				 name_suffix);
+		else
+			snprintf(channel_name, STRING_SIZE, "%s", name_suffix);
+
+		/* this increments the reference count of this instance */
+		c = create_most_c_obj(channel_name, &inst->kobj);
+		if (!c)
+			goto free_instance;
+		inst->channel[i] = c;
+		c->is_starving = 0;
+		c->iface = iface;
+		c->inst = inst;
+		c->channel_id = i;
+		c->keep_mbo = false;
+		c->enqueue_halt = false;
+		c->is_poisoned = false;
+		c->cfg.direction = 0;
+		c->cfg.data_type = 0;
+		c->cfg.num_buffers = 0;
+		c->cfg.buffer_size = 0;
+		c->cfg.subbuffer_size = 0;
+		c->cfg.packets_per_xact = 0;
+		spin_lock_init(&c->fifo_lock);
+		INIT_LIST_HEAD(&c->fifo);
+		INIT_LIST_HEAD(&c->trash_fifo);
+		INIT_LIST_HEAD(&c->halt_fifo);
+		init_completion(&c->cleanup);
+		atomic_set(&c->mbo_ref, 0);
+		mutex_init(&c->start_mutex);
+		mutex_init(&c->nq_mutex);
+		list_add_tail(&c->list, &inst->channel_list);
+	}
+	pr_info("registered new MOST device mdev%d (%s)\n",
+		inst->dev_id, iface->description);
+	return &inst->kobj;
+
+free_instance:
+	pr_info("Failed allocate channel(s)\n");
+	list_del(&inst->list);
+	ida_simple_remove(&mdev_id, id);
+	destroy_most_inst_obj(inst);
+	return ERR_PTR(-ENOMEM);
+}
+EXPORT_SYMBOL_GPL(most_register_interface);
+
+/**
+ * most_deregister_interface - deregisters an interface with core
+ * @iface: pointer to the interface instance description.
+ *
+ * Before removing an interface instance from the list, all running
+ * channels are stopped and poisoned.
+ */
+void most_deregister_interface(struct most_interface *iface)
+{
+	struct most_inst_obj *i = iface->priv;
+	struct most_c_obj *c;
+
+	if (unlikely(!i)) {
+		pr_info("Bad Interface\n");
+		return;
+	}
+	pr_info("deregistering MOST device %s (%s)\n", i->kobj.name,
+		iface->description);
+
+	list_for_each_entry(c, &i->channel_list, list) {
+		if (c->aim0.ptr)
+			c->aim0.ptr->disconnect_channel(c->iface,
+							c->channel_id);
+		if (c->aim1.ptr)
+			c->aim1.ptr->disconnect_channel(c->iface,
+							c->channel_id);
+		c->aim0.ptr = NULL;
+		c->aim1.ptr = NULL;
+	}
+
+	ida_simple_remove(&mdev_id, i->dev_id);
+	list_del(&i->list);
+	destroy_most_inst_obj(i);
+}
+EXPORT_SYMBOL_GPL(most_deregister_interface);
+
+/**
+ * most_stop_enqueue - prevents core from enqueueing MBOs
+ * @iface: pointer to interface
+ * @id: channel id
+ *
+ * This is called by an HDM that _cannot_ attend to its duties and
+ * is imminent to get run over by the core. The core is not going to
+ * enqueue any further packets unless the flagging HDM calls
+ * most_resume enqueue().
+ */
+void most_stop_enqueue(struct most_interface *iface, int id)
+{
+	struct most_c_obj *c = get_channel_by_iface(iface, id);
+
+	if (!c)
+		return;
+
+	mutex_lock(&c->nq_mutex);
+	c->enqueue_halt = true;
+	mutex_unlock(&c->nq_mutex);
+}
+EXPORT_SYMBOL_GPL(most_stop_enqueue);
+
+/**
+ * most_resume_enqueue - allow core to enqueue MBOs again
+ * @iface: pointer to interface
+ * @id: channel id
+ *
+ * This clears the enqueue halt flag and enqueues all MBOs currently
+ * sitting in the wait fifo.
+ */
+void most_resume_enqueue(struct most_interface *iface, int id)
+{
+	struct most_c_obj *c = get_channel_by_iface(iface, id);
+
+	if (!c)
+		return;
+
+	mutex_lock(&c->nq_mutex);
+	c->enqueue_halt = false;
+	mutex_unlock(&c->nq_mutex);
+
+	wake_up_interruptible(&c->hdm_fifo_wq);
+}
+EXPORT_SYMBOL_GPL(most_resume_enqueue);
+
+static int __init most_init(void)
+{
+	int err;
+
+	pr_info("init()\n");
+	INIT_LIST_HEAD(&instance_list);
+	INIT_LIST_HEAD(&aim_list);
+	ida_init(&mdev_id);
+
+	err = bus_register(&most_bus);
+	if (err) {
+		pr_info("Cannot register most bus\n");
+		return err;
+	}
+
+	most_class = class_create(THIS_MODULE, "most");
+	if (IS_ERR(most_class)) {
+		pr_info("No udev support.\n");
+		err = PTR_ERR(most_class);
+		goto exit_bus;
+	}
+
+	err = driver_register(&mostcore);
+	if (err) {
+		pr_info("Cannot register core driver\n");
+		goto exit_class;
+	}
+
+	core_dev = device_create(most_class, NULL, 0, NULL, "mostcore");
+	if (IS_ERR(core_dev)) {
+		err = PTR_ERR(core_dev);
+		goto exit_driver;
+	}
+
+	most_aim_kset = kset_create_and_add("aims", NULL, &core_dev->kobj);
+	if (!most_aim_kset) {
+		err = -ENOMEM;
+		goto exit_class_container;
+	}
+
+	most_inst_kset = kset_create_and_add("devices", NULL, &core_dev->kobj);
+	if (!most_inst_kset) {
+		err = -ENOMEM;
+		goto exit_driver_kset;
+	}
+
+	return 0;
+
+exit_driver_kset:
+	kset_unregister(most_aim_kset);
+exit_class_container:
+	device_destroy(most_class, 0);
+exit_driver:
+	driver_unregister(&mostcore);
+exit_class:
+	class_destroy(most_class);
+exit_bus:
+	bus_unregister(&most_bus);
+	return err;
+}
+
+static void __exit most_exit(void)
+{
+	struct most_inst_obj *i, *i_tmp;
+	struct most_aim_obj *d, *d_tmp;
+
+	pr_info("exit core module\n");
+	list_for_each_entry_safe(d, d_tmp, &aim_list, list) {
+		destroy_most_aim_obj(d);
+	}
+
+	list_for_each_entry_safe(i, i_tmp, &instance_list, list) {
+		list_del(&i->list);
+		destroy_most_inst_obj(i);
+	}
+	kset_unregister(most_inst_kset);
+	kset_unregister(most_aim_kset);
+	device_destroy(most_class, 0);
+	driver_unregister(&mostcore);
+	class_destroy(most_class);
+	bus_unregister(&most_bus);
+	ida_destroy(&mdev_id);
+}
+
+module_init(most_init);
+module_exit(most_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Christian Gromm <christian.gromm@microchip.com>");
+MODULE_DESCRIPTION("Core module of stacked MOST Linux driver");
diff --git a/driver/mostcore/mostcore.h b/driver/mostcore/mostcore.h
new file mode 100644
index 0000000..60e018e
--- /dev/null
+++ b/driver/mostcore/mostcore.h
@@ -0,0 +1,320 @@
+/*
+ * mostcore.h - Interface between MostCore,
+ *   Hardware Dependent Module (HDM) and Application Interface Module (AIM).
+ *
+ * Copyright (C) 2013-2015, Microchip Technology Germany II GmbH & Co. KG
+ *
+ * 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.
+ *
+ * This file is licensed under GPLv2.
+ */
+
+/*
+ * Authors:
+ *   Andrey Shvetsov <andrey.shvetsov@k2l.de>
+ *   Christian Gromm <christian.gromm@microchip.com>
+ *   Sebastian Graf
+ */
+
+#ifndef __MOST_CORE_H__
+#define __MOST_CORE_H__
+
+#include <linux/types.h>
+
+struct kobject;
+struct module;
+
+/**
+ * Interface type
+ */
+enum most_interface_type {
+	ITYPE_LOOPBACK = 1,
+	ITYPE_I2C,
+	ITYPE_I2S,
+	ITYPE_TSI,
+	ITYPE_HBI,
+	ITYPE_MEDIALB_DIM,
+	ITYPE_MEDIALB_DIM2,
+	ITYPE_USB,
+	ITYPE_PCIE
+};
+
+/**
+ * Channel direction.
+ */
+enum most_channel_direction {
+	MOST_CH_RX = 1 << 0,
+	MOST_CH_TX = 1 << 1,
+};
+
+/**
+ * Channel data type.
+ */
+enum most_channel_data_type {
+	MOST_CH_CONTROL = 1 << 0,
+	MOST_CH_ASYNC = 1 << 1,
+	MOST_CH_ISOC_AVP = 1 << 2,
+	MOST_CH_SYNC = 1 << 5,
+};
+
+enum mbo_status_flags {
+	/* MBO was processed successfully (data was send or received )*/
+	MBO_SUCCESS = 0,
+	/* The MBO contains wrong or missing information.  */
+	MBO_E_INVAL,
+	/* MBO was completed as HDM Channel will be closed */
+	MBO_E_CLOSE,
+};
+
+/**
+ * struct most_channel_capability - Channel capability
+ * @direction: Supported channel directions.
+ * The value is bitwise OR-combination of the values from the
+ * enumeration most_channel_direction. Zero is allowed value and means
+ * "channel may not be used".
+ * @data_type: Supported channel data types.
+ * The value is bitwise OR-combination of the values from the
+ * enumeration most_channel_data_type. Zero is allowed value and means
+ * "channel may not be used".
+ * @num_buffer_packet: Maximum number of buffers supported by this channel
+ * for packet data types (Async,Control,QoS)
+ * @buffer_size_packet: Maximum buffer size supported by this channel
+ * for packet data types (Async,Control,QoS)
+ * @num_buffer_streaming: Maximum number of buffers supported by this channel
+ * for streaming data types (Sync,AV Packetized)
+ * @buffer_size_streaming: Maximum buffer size supported by this channel
+ * for streaming data types (Sync,AV Packetized)
+ * @name_suffix: Optional suffix providean by an HDM that is attached to the
+ * regular channel name.
+ *
+ * Describes the capabilities of a MostCore channel like supported Data Types
+ * and directions. This information is provided by an HDM for the MostCore.
+ *
+ * The Core creates read only sysfs attribute files in
+ * /sys/devices/virtual/most/mostcore/devices/mdev-#/mdev#-ch#/ with the
+ * following attributes:
+ *	-available_directions
+ *	-available_datatypes
+ *	-number_of_packet_buffers
+ *	-number_of_stream_buffers
+ *	-size_of_packet_buffer
+ *	-size_of_stream_buffer
+ * where content of each file is a string with all supported properties of this
+ * very channel attribute.
+ */
+struct most_channel_capability {
+	u16 direction;
+	u16 data_type;
+	u16 num_buffers_packet;
+	u16 buffer_size_packet;
+	u16 num_buffers_streaming;
+	u16 buffer_size_streaming;
+	char *name_suffix;
+};
+
+/**
+ * struct most_channel_config - stores channel configuration
+ * @direction: direction of the channel
+ * @data_type: data type travelling over this channel
+ * @num_buffers: number of buffers
+ * @buffer_size: size of a buffer for AIM.
+ * Buffer size may be cutted down by HDM in a configure callback
+ * to match to a given interface and channel type.
+ * @extra_len: additional buffer space for internal HDM purposes like padding.
+ * May be set by HDM in a configure callback if needed.
+ * @subbuffer_size: size of a subbuffer
+ * @packets_per_xact: number of MOST frames that are packet inside one USB
+ *		      packet. This is USB specific
+ *
+ * Describes the configuration for a MostCore channel. This information is
+ * provided from the MostCore to a HDM (like the Medusa PCIe Interface) as a
+ * parameter of the "configure" function call.
+ */
+struct most_channel_config {
+	enum most_channel_direction direction;
+	enum most_channel_data_type data_type;
+	u16 num_buffers;
+	u16 buffer_size;
+	u16 extra_len;
+	u16 subbuffer_size;
+	u16 packets_per_xact;
+};
+
+/*
+ * struct mbo - MOST Buffer Object.
+ * @context: context for core completion handler
+ * @priv: private data for HDM
+ *
+ *	public: documented fields that are used for the communications
+ *	between MostCore and HDMs
+ *
+ * @list: list head for use by the mbo's current owner
+ * @ifp: (in) associated interface instance
+ * @hdm_channel_id: (in) HDM channel instance
+ * @virt_address: (in) kernel virtual address of the buffer
+ * @bus_address: (in) bus address of the buffer
+ * @buffer_length: (in) buffer payload length
+ * @processed_length: (out) processed length
+ * @status: (out) transfer status
+ * @complete: (in) completion routine
+ *
+ * The MostCore allocates and initializes the MBO.
+ *
+ * The HDM receives MBO for transfer from MostCore with the call to enqueue().
+ * The HDM copies the data to- or from the buffer depending on configured
+ * channel direction, set "processed_length" and "status" and completes
+ * the transfer procedure by calling the completion routine.
+ *
+ * At the end the MostCore deallocates the MBO or recycles it for further
+ * transfers for the same or different HDM.
+ *
+ * Directions of usage:
+ * The core driver should never access any MBO fields (even if marked
+ * as "public") while the MBO is owned by an HDM. The ownership starts with
+ * the call of enqueue() and ends with the call of its complete() routine.
+ *
+ *					II.
+ * Every HDM attached to the core driver _must_ ensure that it returns any MBO
+ * it owns (due to a previous call to enqueue() by the core driver) before it
+ * de-registers an interface or gets unloaded from the kernel. If this direction
+ * is violated memory leaks will occur, since the core driver does _not_ track
+ * MBOs it is currently not in control of.
+ *
+ */
+struct mbo {
+	void *context;
+	void *priv;
+	struct list_head list;
+	struct most_interface *ifp;
+	int *num_buffers_ptr;
+	u16 hdm_channel_id;
+	void *virt_address;
+	dma_addr_t bus_address;
+	u16 buffer_length;
+	u16 processed_length;
+	enum mbo_status_flags status;
+	void (*complete)(struct mbo *);
+};
+
+/**
+ * Interface instance description.
+ *
+ * Describes one instance of an interface like Medusa PCIe or Vantage USB.
+ * This structure is allocated and initialized in the HDM. MostCore may not
+ * modify this structure.
+ *
+ * @interface Interface type. \sa most_interface_type.
+ * @description PRELIMINARY.
+ *   Unique description of the device instance from point of view of the
+ *   interface in free text form (ASCII).
+ *   It may be a hexadecimal presentation of the memory address for the MediaLB
+ *   IP or USB device ID with USB properties for USB interface, etc.
+ * @num_channels Number of channels and size of the channel_vector.
+ * @channel_vector Properties of the channels.
+ *   Array index represents channel ID by the driver.
+ * @configure Callback to change data type for the channel of the
+ *   interface instance. May be zero if the instance of the interface is not
+ *   configurable. Parameter channel_config describes direction and data
+ *   type for the channel, configured by the higher level. The content of
+ * @enqueue Delivers MBO to the HDM for processing.
+ *   After HDM completes Rx- or Tx- operation the processed MBO shall
+ *   be returned back to the MostCore using completion routine.
+ *   The reason to get the MBO delivered from the MostCore after the channel
+ *   is poisoned is the re-opening of the channel by the application.
+ *   In this case the HDM shall hold MBOs and service the channel as usual.
+ *   The HDM must be able to hold at least one MBO for each channel.
+ *   The callback returns a negative value on error, otherwise 0.
+ * @poison_channel Informs HDM about closing the channel. The HDM shall
+ *   cancel all transfers and synchronously or asynchronously return
+ *   all enqueued for this channel MBOs using the completion routine.
+ *   The callback returns a negative value on error, otherwise 0.
+ * @request_netinfo: triggers retrieving of network info from the HDM by
+ *   means of "Message exchange over MDP/MEP"
+ * @priv Private field used by mostcore to store context information.
+ */
+struct most_interface {
+	struct module *mod;
+	enum most_interface_type interface;
+	const char *description;
+	int num_channels;
+	struct most_channel_capability *channel_vector;
+	int (*configure)(struct most_interface *iface, int channel_idx,
+			 struct most_channel_config *channel_config);
+	int (*enqueue)(struct most_interface *iface, int channel_idx,
+		       struct mbo *mbo);
+	int (*poison_channel)(struct most_interface *iface, int channel_idx);
+	void (*request_netinfo)(struct most_interface *iface, int channel_idx);
+	void *priv;
+};
+
+/**
+ * struct most_aim - identifies MOST device driver to mostcore
+ * @name: Driver name
+ * @probe_channel: function for core to notify driver about channel connection
+ * @disconnect_channel: callback function to disconnect a certain channel
+ * @rx_completion: completion handler for received packets
+ * @tx_completion: completion handler for transmitted packets
+ * @context: context pointer to be used by mostcore
+ */
+struct most_aim {
+	const char *name;
+	int (*probe_channel)(struct most_interface *iface, int channel_idx,
+			     struct most_channel_config *cfg,
+			     struct kobject *parent, char *name);
+	int (*disconnect_channel)(struct most_interface *iface,
+				  int channel_idx);
+	int (*rx_completion)(struct mbo *mbo);
+	int (*tx_completion)(struct most_interface *iface, int channel_idx);
+	void *context;
+};
+
+/**
+ * most_register_interface - Registers instance of the interface.
+ * @iface: Pointer to the interface instance description.
+ *
+ * Returns a pointer to the kobject of the generated instance.
+ *
+ * Note: HDM has to ensure that any reference held on the kobj is
+ * released before deregistering the interface.
+ */
+struct kobject *most_register_interface(struct most_interface *iface);
+
+/**
+ * Deregisters instance of the interface.
+ * @intf_instance Pointer to the interface instance description.
+ */
+void most_deregister_interface(struct most_interface *iface);
+int most_submit_mbo(struct mbo *mbo);
+
+/**
+ * most_stop_enqueue - prevents core from enqueing MBOs
+ * @iface: pointer to interface
+ * @channel_idx: channel index
+ */
+void most_stop_enqueue(struct most_interface *iface, int channel_idx);
+
+/**
+ * most_resume_enqueue - allow core to enqueue MBOs again
+ * @iface: pointer to interface
+ * @channel_idx: channel index
+ *
+ * This clears the enqueue halt flag and enqueues all MBOs currently
+ * in wait fifo.
+ */
+void most_resume_enqueue(struct most_interface *iface, int channel_idx);
+int most_register_aim(struct most_aim *aim);
+int most_deregister_aim(struct most_aim *aim);
+struct mbo *most_get_mbo(struct most_interface *iface, int channel_idx,
+			 struct most_aim *);
+void most_put_mbo(struct mbo *mbo);
+int channel_has_mbo(struct most_interface *iface, int channel_idx,
+		    struct most_aim *aim);
+int most_start_channel(struct most_interface *iface, int channel_idx,
+		       struct most_aim *);
+int most_stop_channel(struct most_interface *iface, int channel_idx,
+		      struct most_aim *);
+
+#endif /* MOST_CORE_H_ */