Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1844 insertions, 0 deletions

diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
new file mode 100644
index 000000000..524b8c0d3
--- /dev/null
+++ b/drivers/misc/mei/client.c
@@ -0,0 +1,1844 @@
+/*
+ *
+ * Intel Management Engine Interface (Intel MEI) Linux driver
+ * Copyright (c) 2003-2012, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/sched/signal.h>
+#include <linux/wait.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/pm_runtime.h>
+
+#include <linux/mei.h>
+
+#include "mei_dev.h"
+#include "hbm.h"
+#include "client.h"
+
+/**
+ * mei_me_cl_init - initialize me client
+ *
+ * @me_cl: me client
+ */
+void mei_me_cl_init(struct mei_me_client *me_cl)
+{
+	INIT_LIST_HEAD(&me_cl->list);
+	kref_init(&me_cl->refcnt);
+}
+
+/**
+ * mei_me_cl_get - increases me client refcount
+ *
+ * @me_cl: me client
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * Return: me client or NULL
+ */
+struct mei_me_client *mei_me_cl_get(struct mei_me_client *me_cl)
+{
+	if (me_cl && kref_get_unless_zero(&me_cl->refcnt))
+		return me_cl;
+
+	return NULL;
+}
+
+/**
+ * mei_me_cl_release - free me client
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * @ref: me_client refcount
+ */
+static void mei_me_cl_release(struct kref *ref)
+{
+	struct mei_me_client *me_cl =
+		container_of(ref, struct mei_me_client, refcnt);
+
+	kfree(me_cl);
+}
+
+/**
+ * mei_me_cl_put - decrease me client refcount and free client if necessary
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * @me_cl: me client
+ */
+void mei_me_cl_put(struct mei_me_client *me_cl)
+{
+	if (me_cl)
+		kref_put(&me_cl->refcnt, mei_me_cl_release);
+}
+
+/**
+ * __mei_me_cl_del  - delete me client from the list and decrease
+ *     reference counter
+ *
+ * @dev: mei device
+ * @me_cl: me client
+ *
+ * Locking: dev->me_clients_rwsem
+ */
+static void __mei_me_cl_del(struct mei_device *dev, struct mei_me_client *me_cl)
+{
+	if (!me_cl)
+		return;
+
+	list_del_init(&me_cl->list);
+	mei_me_cl_put(me_cl);
+}
+
+/**
+ * mei_me_cl_del - delete me client from the list and decrease
+ *     reference counter
+ *
+ * @dev: mei device
+ * @me_cl: me client
+ */
+void mei_me_cl_del(struct mei_device *dev, struct mei_me_client *me_cl)
+{
+	down_write(&dev->me_clients_rwsem);
+	__mei_me_cl_del(dev, me_cl);
+	up_write(&dev->me_clients_rwsem);
+}
+
+/**
+ * mei_me_cl_add - add me client to the list
+ *
+ * @dev: mei device
+ * @me_cl: me client
+ */
+void mei_me_cl_add(struct mei_device *dev, struct mei_me_client *me_cl)
+{
+	down_write(&dev->me_clients_rwsem);
+	list_add(&me_cl->list, &dev->me_clients);
+	up_write(&dev->me_clients_rwsem);
+}
+
+/**
+ * __mei_me_cl_by_uuid - locate me client by uuid
+ *	increases ref count
+ *
+ * @dev: mei device
+ * @uuid: me client uuid
+ *
+ * Return: me client or NULL if not found
+ *
+ * Locking: dev->me_clients_rwsem
+ */
+static struct mei_me_client *__mei_me_cl_by_uuid(struct mei_device *dev,
+					const uuid_le *uuid)
+{
+	struct mei_me_client *me_cl;
+	const uuid_le *pn;
+
+	WARN_ON(!rwsem_is_locked(&dev->me_clients_rwsem));
+
+	list_for_each_entry(me_cl, &dev->me_clients, list) {
+		pn = &me_cl->props.protocol_name;
+		if (uuid_le_cmp(*uuid, *pn) == 0)
+			return mei_me_cl_get(me_cl);
+	}
+
+	return NULL;
+}
+
+/**
+ * mei_me_cl_by_uuid - locate me client by uuid
+ *	increases ref count
+ *
+ * @dev: mei device
+ * @uuid: me client uuid
+ *
+ * Return: me client or NULL if not found
+ *
+ * Locking: dev->me_clients_rwsem
+ */
+struct mei_me_client *mei_me_cl_by_uuid(struct mei_device *dev,
+					const uuid_le *uuid)
+{
+	struct mei_me_client *me_cl;
+
+	down_read(&dev->me_clients_rwsem);
+	me_cl = __mei_me_cl_by_uuid(dev, uuid);
+	up_read(&dev->me_clients_rwsem);
+
+	return me_cl;
+}
+
+/**
+ * mei_me_cl_by_id - locate me client by client id
+ *	increases ref count
+ *
+ * @dev: the device structure
+ * @client_id: me client id
+ *
+ * Return: me client or NULL if not found
+ *
+ * Locking: dev->me_clients_rwsem
+ */
+struct mei_me_client *mei_me_cl_by_id(struct mei_device *dev, u8 client_id)
+{
+
+	struct mei_me_client *__me_cl, *me_cl = NULL;
+
+	down_read(&dev->me_clients_rwsem);
+	list_for_each_entry(__me_cl, &dev->me_clients, list) {
+		if (__me_cl->client_id == client_id) {
+			me_cl = mei_me_cl_get(__me_cl);
+			break;
+		}
+	}
+	up_read(&dev->me_clients_rwsem);
+
+	return me_cl;
+}
+
+/**
+ * __mei_me_cl_by_uuid_id - locate me client by client id and uuid
+ *	increases ref count
+ *
+ * @dev: the device structure
+ * @uuid: me client uuid
+ * @client_id: me client id
+ *
+ * Return: me client or null if not found
+ *
+ * Locking: dev->me_clients_rwsem
+ */
+static struct mei_me_client *__mei_me_cl_by_uuid_id(struct mei_device *dev,
+					   const uuid_le *uuid, u8 client_id)
+{
+	struct mei_me_client *me_cl;
+	const uuid_le *pn;
+
+	WARN_ON(!rwsem_is_locked(&dev->me_clients_rwsem));
+
+	list_for_each_entry(me_cl, &dev->me_clients, list) {
+		pn = &me_cl->props.protocol_name;
+		if (uuid_le_cmp(*uuid, *pn) == 0 &&
+		    me_cl->client_id == client_id)
+			return mei_me_cl_get(me_cl);
+	}
+
+	return NULL;
+}
+
+
+/**
+ * mei_me_cl_by_uuid_id - locate me client by client id and uuid
+ *	increases ref count
+ *
+ * @dev: the device structure
+ * @uuid: me client uuid
+ * @client_id: me client id
+ *
+ * Return: me client or null if not found
+ */
+struct mei_me_client *mei_me_cl_by_uuid_id(struct mei_device *dev,
+					   const uuid_le *uuid, u8 client_id)
+{
+	struct mei_me_client *me_cl;
+
+	down_read(&dev->me_clients_rwsem);
+	me_cl = __mei_me_cl_by_uuid_id(dev, uuid, client_id);
+	up_read(&dev->me_clients_rwsem);
+
+	return me_cl;
+}
+
+/**
+ * mei_me_cl_rm_by_uuid - remove all me clients matching uuid
+ *
+ * @dev: the device structure
+ * @uuid: me client uuid
+ *
+ * Locking: called under "dev->device_lock" lock
+ */
+void mei_me_cl_rm_by_uuid(struct mei_device *dev, const uuid_le *uuid)
+{
+	struct mei_me_client *me_cl;
+
+	dev_dbg(dev->dev, "remove %pUl\n", uuid);
+
+	down_write(&dev->me_clients_rwsem);
+	me_cl = __mei_me_cl_by_uuid(dev, uuid);
+	__mei_me_cl_del(dev, me_cl);
+	mei_me_cl_put(me_cl);
+	up_write(&dev->me_clients_rwsem);
+}
+
+/**
+ * mei_me_cl_rm_by_uuid_id - remove all me clients matching client id
+ *
+ * @dev: the device structure
+ * @uuid: me client uuid
+ * @id: me client id
+ *
+ * Locking: called under "dev->device_lock" lock
+ */
+void mei_me_cl_rm_by_uuid_id(struct mei_device *dev, const uuid_le *uuid, u8 id)
+{
+	struct mei_me_client *me_cl;
+
+	dev_dbg(dev->dev, "remove %pUl %d\n", uuid, id);
+
+	down_write(&dev->me_clients_rwsem);
+	me_cl = __mei_me_cl_by_uuid_id(dev, uuid, id);
+	__mei_me_cl_del(dev, me_cl);
+	mei_me_cl_put(me_cl);
+	up_write(&dev->me_clients_rwsem);
+}
+
+/**
+ * mei_me_cl_rm_all - remove all me clients
+ *
+ * @dev: the device structure
+ *
+ * Locking: called under "dev->device_lock" lock
+ */
+void mei_me_cl_rm_all(struct mei_device *dev)
+{
+	struct mei_me_client *me_cl, *next;
+
+	down_write(&dev->me_clients_rwsem);
+	list_for_each_entry_safe(me_cl, next, &dev->me_clients, list)
+		__mei_me_cl_del(dev, me_cl);
+	up_write(&dev->me_clients_rwsem);
+}
+
+/**
+ * mei_cl_cmp_id - tells if the clients are the same
+ *
+ * @cl1: host client 1
+ * @cl2: host client 2
+ *
+ * Return: true  - if the clients has same host and me ids
+ *         false - otherwise
+ */
+static inline bool mei_cl_cmp_id(const struct mei_cl *cl1,
+				const struct mei_cl *cl2)
+{
+	return cl1 && cl2 &&
+		(cl1->host_client_id == cl2->host_client_id) &&
+		(mei_cl_me_id(cl1) == mei_cl_me_id(cl2));
+}
+
+/**
+ * mei_io_cb_free - free mei_cb_private related memory
+ *
+ * @cb: mei callback struct
+ */
+void mei_io_cb_free(struct mei_cl_cb *cb)
+{
+	if (cb == NULL)
+		return;
+
+	list_del(&cb->list);
+	kfree(cb->buf.data);
+	kfree(cb);
+}
+
+/**
+ * mei_tx_cb_queue - queue tx callback
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * @cb: mei callback struct
+ * @head: an instance of list to queue on
+ */
+static inline void mei_tx_cb_enqueue(struct mei_cl_cb *cb,
+				     struct list_head *head)
+{
+	list_add_tail(&cb->list, head);
+	cb->cl->tx_cb_queued++;
+}
+
+/**
+ * mei_tx_cb_dequeue - dequeue tx callback
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * @cb: mei callback struct to dequeue and free
+ */
+static inline void mei_tx_cb_dequeue(struct mei_cl_cb *cb)
+{
+	if (!WARN_ON(cb->cl->tx_cb_queued == 0))
+		cb->cl->tx_cb_queued--;
+
+	mei_io_cb_free(cb);
+}
+
+/**
+ * mei_io_cb_init - allocate and initialize io callback
+ *
+ * @cl: mei client
+ * @type: operation type
+ * @fp: pointer to file structure
+ *
+ * Return: mei_cl_cb pointer or NULL;
+ */
+static struct mei_cl_cb *mei_io_cb_init(struct mei_cl *cl,
+					enum mei_cb_file_ops type,
+					const struct file *fp)
+{
+	struct mei_cl_cb *cb;
+
+	cb = kzalloc(sizeof(struct mei_cl_cb), GFP_KERNEL);
+	if (!cb)
+		return NULL;
+
+	INIT_LIST_HEAD(&cb->list);
+	cb->fp = fp;
+	cb->cl = cl;
+	cb->buf_idx = 0;
+	cb->fop_type = type;
+	return cb;
+}
+
+/**
+ * mei_io_list_flush_cl - removes cbs belonging to the cl.
+ *
+ * @head:  an instance of our list structure
+ * @cl:    host client
+ */
+static void mei_io_list_flush_cl(struct list_head *head,
+				 const struct mei_cl *cl)
+{
+	struct mei_cl_cb *cb, *next;
+
+	list_for_each_entry_safe(cb, next, head, list) {
+		if (mei_cl_cmp_id(cl, cb->cl))
+			list_del_init(&cb->list);
+	}
+}
+
+/**
+ * mei_io_tx_list_free_cl - removes cb belonging to the cl and free them
+ *
+ * @head: An instance of our list structure
+ * @cl: host client
+ */
+static void mei_io_tx_list_free_cl(struct list_head *head,
+				   const struct mei_cl *cl)
+{
+	struct mei_cl_cb *cb, *next;
+
+	list_for_each_entry_safe(cb, next, head, list) {
+		if (mei_cl_cmp_id(cl, cb->cl))
+			mei_tx_cb_dequeue(cb);
+	}
+}
+
+/**
+ * mei_io_list_free_fp - free cb from a list that matches file pointer
+ *
+ * @head: io list
+ * @fp: file pointer (matching cb file object), may be NULL
+ */
+static void mei_io_list_free_fp(struct list_head *head, const struct file *fp)
+{
+	struct mei_cl_cb *cb, *next;
+
+	list_for_each_entry_safe(cb, next, head, list)
+		if (!fp || fp == cb->fp)
+			mei_io_cb_free(cb);
+}
+
+/**
+ * mei_cl_alloc_cb - a convenient wrapper for allocating read cb
+ *
+ * @cl: host client
+ * @length: size of the buffer
+ * @fop_type: operation type
+ * @fp: associated file pointer (might be NULL)
+ *
+ * Return: cb on success and NULL on failure
+ */
+struct mei_cl_cb *mei_cl_alloc_cb(struct mei_cl *cl, size_t length,
+				  enum mei_cb_file_ops fop_type,
+				  const struct file *fp)
+{
+	struct mei_cl_cb *cb;
+
+	cb = mei_io_cb_init(cl, fop_type, fp);
+	if (!cb)
+		return NULL;
+
+	if (length == 0)
+		return cb;
+
+	cb->buf.data = kmalloc(length, GFP_KERNEL);
+	if (!cb->buf.data) {
+		mei_io_cb_free(cb);
+		return NULL;
+	}
+	cb->buf.size = length;
+
+	return cb;
+}
+
+/**
+ * mei_cl_enqueue_ctrl_wr_cb - a convenient wrapper for allocating
+ *     and enqueuing of the control commands cb
+ *
+ * @cl: host client
+ * @length: size of the buffer
+ * @fop_type: operation type
+ * @fp: associated file pointer (might be NULL)
+ *
+ * Return: cb on success and NULL on failure
+ * Locking: called under "dev->device_lock" lock
+ */
+struct mei_cl_cb *mei_cl_enqueue_ctrl_wr_cb(struct mei_cl *cl, size_t length,
+					    enum mei_cb_file_ops fop_type,
+					    const struct file *fp)
+{
+	struct mei_cl_cb *cb;
+
+	/* for RX always allocate at least client's mtu */
+	if (length)
+		length = max_t(size_t, length, mei_cl_mtu(cl));
+
+	cb = mei_cl_alloc_cb(cl, length, fop_type, fp);
+	if (!cb)
+		return NULL;
+
+	list_add_tail(&cb->list, &cl->dev->ctrl_wr_list);
+	return cb;
+}
+
+/**
+ * mei_cl_read_cb - find this cl's callback in the read list
+ *     for a specific file
+ *
+ * @cl: host client
+ * @fp: file pointer (matching cb file object), may be NULL
+ *
+ * Return: cb on success, NULL if cb is not found
+ */
+struct mei_cl_cb *mei_cl_read_cb(const struct mei_cl *cl, const struct file *fp)
+{
+	struct mei_cl_cb *cb;
+
+	list_for_each_entry(cb, &cl->rd_completed, list)
+		if (!fp || fp == cb->fp)
+			return cb;
+
+	return NULL;
+}
+
+/**
+ * mei_cl_flush_queues - flushes queue lists belonging to cl.
+ *
+ * @cl: host client
+ * @fp: file pointer (matching cb file object), may be NULL
+ *
+ * Return: 0 on success, -EINVAL if cl or cl->dev is NULL.
+ */
+int mei_cl_flush_queues(struct mei_cl *cl, const struct file *fp)
+{
+	struct mei_device *dev;
+
+	if (WARN_ON(!cl || !cl->dev))
+		return -EINVAL;
+
+	dev = cl->dev;
+
+	cl_dbg(dev, cl, "remove list entry belonging to cl\n");
+	mei_io_tx_list_free_cl(&cl->dev->write_list, cl);
+	mei_io_tx_list_free_cl(&cl->dev->write_waiting_list, cl);
+	mei_io_list_flush_cl(&cl->dev->ctrl_wr_list, cl);
+	mei_io_list_flush_cl(&cl->dev->ctrl_rd_list, cl);
+	mei_io_list_free_fp(&cl->rd_pending, fp);
+	mei_io_list_free_fp(&cl->rd_completed, fp);
+
+	return 0;
+}
+
+/**
+ * mei_cl_init - initializes cl.
+ *
+ * @cl: host client to be initialized
+ * @dev: mei device
+ */
+static void mei_cl_init(struct mei_cl *cl, struct mei_device *dev)
+{
+	memset(cl, 0, sizeof(struct mei_cl));
+	init_waitqueue_head(&cl->wait);
+	init_waitqueue_head(&cl->rx_wait);
+	init_waitqueue_head(&cl->tx_wait);
+	init_waitqueue_head(&cl->ev_wait);
+	INIT_LIST_HEAD(&cl->rd_completed);
+	INIT_LIST_HEAD(&cl->rd_pending);
+	INIT_LIST_HEAD(&cl->link);
+	cl->writing_state = MEI_IDLE;
+	cl->state = MEI_FILE_UNINITIALIZED;
+	cl->dev = dev;
+}
+
+/**
+ * mei_cl_allocate - allocates cl  structure and sets it up.
+ *
+ * @dev: mei device
+ * Return:  The allocated file or NULL on failure
+ */
+struct mei_cl *mei_cl_allocate(struct mei_device *dev)
+{
+	struct mei_cl *cl;
+
+	cl = kmalloc(sizeof(struct mei_cl), GFP_KERNEL);
+	if (!cl)
+		return NULL;
+
+	mei_cl_init(cl, dev);
+
+	return cl;
+}
+
+/**
+ * mei_cl_link - allocate host id in the host map
+ *
+ * @cl: host client
+ *
+ * Return: 0 on success
+ *	-EINVAL on incorrect values
+ *	-EMFILE if open count exceeded.
+ */
+int mei_cl_link(struct mei_cl *cl)
+{
+	struct mei_device *dev;
+	int id;
+
+	if (WARN_ON(!cl || !cl->dev))
+		return -EINVAL;
+
+	dev = cl->dev;
+
+	id = find_first_zero_bit(dev->host_clients_map, MEI_CLIENTS_MAX);
+	if (id >= MEI_CLIENTS_MAX) {
+		dev_err(dev->dev, "id exceeded %d", MEI_CLIENTS_MAX);
+		return -EMFILE;
+	}
+
+	if (dev->open_handle_count >= MEI_MAX_OPEN_HANDLE_COUNT) {
+		dev_err(dev->dev, "open_handle_count exceeded %d",
+			MEI_MAX_OPEN_HANDLE_COUNT);
+		return -EMFILE;
+	}
+
+	dev->open_handle_count++;
+
+	cl->host_client_id = id;
+	list_add_tail(&cl->link, &dev->file_list);
+
+	set_bit(id, dev->host_clients_map);
+
+	cl->state = MEI_FILE_INITIALIZING;
+
+	cl_dbg(dev, cl, "link cl\n");
+	return 0;
+}
+
+/**
+ * mei_cl_unlink - remove host client from the list
+ *
+ * @cl: host client
+ *
+ * Return: always 0
+ */
+int mei_cl_unlink(struct mei_cl *cl)
+{
+	struct mei_device *dev;
+
+	/* don't shout on error exit path */
+	if (!cl)
+		return 0;
+
+	if (WARN_ON(!cl->dev))
+		return 0;
+
+	dev = cl->dev;
+
+	cl_dbg(dev, cl, "unlink client");
+
+	if (dev->open_handle_count > 0)
+		dev->open_handle_count--;
+
+	/* never clear the 0 bit */
+	if (cl->host_client_id)
+		clear_bit(cl->host_client_id, dev->host_clients_map);
+
+	list_del_init(&cl->link);
+
+	cl->state = MEI_FILE_UNINITIALIZED;
+	cl->writing_state = MEI_IDLE;
+
+	WARN_ON(!list_empty(&cl->rd_completed) ||
+		!list_empty(&cl->rd_pending) ||
+		!list_empty(&cl->link));
+
+	return 0;
+}
+
+void mei_host_client_init(struct mei_device *dev)
+{
+	dev->dev_state = MEI_DEV_ENABLED;
+	dev->reset_count = 0;
+
+	schedule_work(&dev->bus_rescan_work);
+
+	pm_runtime_mark_last_busy(dev->dev);
+	dev_dbg(dev->dev, "rpm: autosuspend\n");
+	pm_request_autosuspend(dev->dev);
+}
+
+/**
+ * mei_hbuf_acquire - try to acquire host buffer
+ *
+ * @dev: the device structure
+ * Return: true if host buffer was acquired
+ */
+bool mei_hbuf_acquire(struct mei_device *dev)
+{
+	if (mei_pg_state(dev) == MEI_PG_ON ||
+	    mei_pg_in_transition(dev)) {
+		dev_dbg(dev->dev, "device is in pg\n");
+		return false;
+	}
+
+	if (!dev->hbuf_is_ready) {
+		dev_dbg(dev->dev, "hbuf is not ready\n");
+		return false;
+	}
+
+	dev->hbuf_is_ready = false;
+
+	return true;
+}
+
+/**
+ * mei_cl_wake_all - wake up readers, writers and event waiters so
+ *                 they can be interrupted
+ *
+ * @cl: host client
+ */
+static void mei_cl_wake_all(struct mei_cl *cl)
+{
+	struct mei_device *dev = cl->dev;
+
+	/* synchronized under device mutex */
+	if (waitqueue_active(&cl->rx_wait)) {
+		cl_dbg(dev, cl, "Waking up reading client!\n");
+		wake_up_interruptible(&cl->rx_wait);
+	}
+	/* synchronized under device mutex */
+	if (waitqueue_active(&cl->tx_wait)) {
+		cl_dbg(dev, cl, "Waking up writing client!\n");
+		wake_up_interruptible(&cl->tx_wait);
+	}
+	/* synchronized under device mutex */
+	if (waitqueue_active(&cl->ev_wait)) {
+		cl_dbg(dev, cl, "Waking up waiting for event clients!\n");
+		wake_up_interruptible(&cl->ev_wait);
+	}
+	/* synchronized under device mutex */
+	if (waitqueue_active(&cl->wait)) {
+		cl_dbg(dev, cl, "Waking up ctrl write clients!\n");
+		wake_up(&cl->wait);
+	}
+}
+
+/**
+ * mei_cl_set_disconnected - set disconnected state and clear
+ *   associated states and resources
+ *
+ * @cl: host client
+ */
+static void mei_cl_set_disconnected(struct mei_cl *cl)
+{
+	struct mei_device *dev = cl->dev;
+
+	if (cl->state == MEI_FILE_DISCONNECTED ||
+	    cl->state <= MEI_FILE_INITIALIZING)
+		return;
+
+	cl->state = MEI_FILE_DISCONNECTED;
+	mei_io_tx_list_free_cl(&dev->write_list, cl);
+	mei_io_tx_list_free_cl(&dev->write_waiting_list, cl);
+	mei_io_list_flush_cl(&dev->ctrl_rd_list, cl);
+	mei_io_list_flush_cl(&dev->ctrl_wr_list, cl);
+	mei_cl_wake_all(cl);
+	cl->rx_flow_ctrl_creds = 0;
+	cl->tx_flow_ctrl_creds = 0;
+	cl->timer_count = 0;
+
+	if (!cl->me_cl)
+		return;
+
+	if (!WARN_ON(cl->me_cl->connect_count == 0))
+		cl->me_cl->connect_count--;
+
+	if (cl->me_cl->connect_count == 0)
+		cl->me_cl->tx_flow_ctrl_creds = 0;
+
+	mei_me_cl_put(cl->me_cl);
+	cl->me_cl = NULL;
+}
+
+static int mei_cl_set_connecting(struct mei_cl *cl, struct mei_me_client *me_cl)
+{
+	if (!mei_me_cl_get(me_cl))
+		return -ENOENT;
+
+	/* only one connection is allowed for fixed address clients */
+	if (me_cl->props.fixed_address) {
+		if (me_cl->connect_count) {
+			mei_me_cl_put(me_cl);
+			return -EBUSY;
+		}
+	}
+
+	cl->me_cl = me_cl;
+	cl->state = MEI_FILE_CONNECTING;
+	cl->me_cl->connect_count++;
+
+	return 0;
+}
+
+/*
+ * mei_cl_send_disconnect - send disconnect request
+ *
+ * @cl: host client
+ * @cb: callback block
+ *
+ * Return: 0, OK; otherwise, error.
+ */
+static int mei_cl_send_disconnect(struct mei_cl *cl, struct mei_cl_cb *cb)
+{
+	struct mei_device *dev;
+	int ret;
+
+	dev = cl->dev;
+
+	ret = mei_hbm_cl_disconnect_req(dev, cl);
+	cl->status = ret;
+	if (ret) {
+		cl->state = MEI_FILE_DISCONNECT_REPLY;
+		return ret;
+	}
+
+	list_move_tail(&cb->list, &dev->ctrl_rd_list);
+	cl->timer_count = MEI_CONNECT_TIMEOUT;
+	mei_schedule_stall_timer(dev);
+
+	return 0;
+}
+
+/**
+ * mei_cl_irq_disconnect - processes close related operation from
+ *	interrupt thread context - send disconnect request
+ *
+ * @cl: client
+ * @cb: callback block.
+ * @cmpl_list: complete list.
+ *
+ * Return: 0, OK; otherwise, error.
+ */
+int mei_cl_irq_disconnect(struct mei_cl *cl, struct mei_cl_cb *cb,
+			  struct list_head *cmpl_list)
+{
+	struct mei_device *dev = cl->dev;
+	u32 msg_slots;
+	int slots;
+	int ret;
+
+	msg_slots = mei_hbm2slots(sizeof(struct hbm_client_connect_request));
+	slots = mei_hbuf_empty_slots(dev);
+	if (slots < 0)
+		return -EOVERFLOW;
+
+	if ((u32)slots < msg_slots)
+		return -EMSGSIZE;
+
+	ret = mei_cl_send_disconnect(cl, cb);
+	if (ret)
+		list_move_tail(&cb->list, cmpl_list);
+
+	return ret;
+}
+
+/**
+ * __mei_cl_disconnect - disconnect host client from the me one
+ *     internal function runtime pm has to be already acquired
+ *
+ * @cl: host client
+ *
+ * Return: 0 on success, <0 on failure.
+ */
+static int __mei_cl_disconnect(struct mei_cl *cl)
+{
+	struct mei_device *dev;
+	struct mei_cl_cb *cb;
+	int rets;
+
+	dev = cl->dev;
+
+	cl->state = MEI_FILE_DISCONNECTING;
+
+	cb = mei_cl_enqueue_ctrl_wr_cb(cl, 0, MEI_FOP_DISCONNECT, NULL);
+	if (!cb) {
+		rets = -ENOMEM;
+		goto out;
+	}
+
+	if (mei_hbuf_acquire(dev)) {
+		rets = mei_cl_send_disconnect(cl, cb);
+		if (rets) {
+			cl_err(dev, cl, "failed to disconnect.\n");
+			goto out;
+		}
+	}
+
+	mutex_unlock(&dev->device_lock);
+	wait_event_timeout(cl->wait,
+			   cl->state == MEI_FILE_DISCONNECT_REPLY ||
+			   cl->state == MEI_FILE_DISCONNECTED,
+			   mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT));
+	mutex_lock(&dev->device_lock);
+
+	rets = cl->status;
+	if (cl->state != MEI_FILE_DISCONNECT_REPLY &&
+	    cl->state != MEI_FILE_DISCONNECTED) {
+		cl_dbg(dev, cl, "timeout on disconnect from FW client.\n");
+		rets = -ETIME;
+	}
+
+out:
+	/* we disconnect also on error */
+	mei_cl_set_disconnected(cl);
+	if (!rets)
+		cl_dbg(dev, cl, "successfully disconnected from FW client.\n");
+
+	mei_io_cb_free(cb);
+	return rets;
+}
+
+/**
+ * mei_cl_disconnect - disconnect host client from the me one
+ *
+ * @cl: host client
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * Return: 0 on success, <0 on failure.
+ */
+int mei_cl_disconnect(struct mei_cl *cl)
+{
+	struct mei_device *dev;
+	int rets;
+
+	if (WARN_ON(!cl || !cl->dev))
+		return -ENODEV;
+
+	dev = cl->dev;
+
+	cl_dbg(dev, cl, "disconnecting");
+
+	if (!mei_cl_is_connected(cl))
+		return 0;
+
+	if (mei_cl_is_fixed_address(cl)) {
+		mei_cl_set_disconnected(cl);
+		return 0;
+	}
+
+	if (dev->dev_state == MEI_DEV_POWER_DOWN) {
+		cl_dbg(dev, cl, "Device is powering down, don't bother with disconnection\n");
+		mei_cl_set_disconnected(cl);
+		return 0;
+	}
+
+	rets = pm_runtime_get(dev->dev);
+	if (rets < 0 && rets != -EINPROGRESS) {
+		pm_runtime_put_noidle(dev->dev);
+		cl_err(dev, cl, "rpm: get failed %d\n", rets);
+		return rets;
+	}
+
+	rets = __mei_cl_disconnect(cl);
+
+	cl_dbg(dev, cl, "rpm: autosuspend\n");
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
+
+	return rets;
+}
+
+
+/**
+ * mei_cl_is_other_connecting - checks if other
+ *    client with the same me client id is connecting
+ *
+ * @cl: private data of the file object
+ *
+ * Return: true if other client is connected, false - otherwise.
+ */
+static bool mei_cl_is_other_connecting(struct mei_cl *cl)
+{
+	struct mei_device *dev;
+	struct mei_cl_cb *cb;
+
+	dev = cl->dev;
+
+	list_for_each_entry(cb, &dev->ctrl_rd_list, list) {
+		if (cb->fop_type == MEI_FOP_CONNECT &&
+		    mei_cl_me_id(cl) == mei_cl_me_id(cb->cl))
+			return true;
+	}
+
+	return false;
+}
+
+/**
+ * mei_cl_send_connect - send connect request
+ *
+ * @cl: host client
+ * @cb: callback block
+ *
+ * Return: 0, OK; otherwise, error.
+ */
+static int mei_cl_send_connect(struct mei_cl *cl, struct mei_cl_cb *cb)
+{
+	struct mei_device *dev;
+	int ret;
+
+	dev = cl->dev;
+
+	ret = mei_hbm_cl_connect_req(dev, cl);
+	cl->status = ret;
+	if (ret) {
+		cl->state = MEI_FILE_DISCONNECT_REPLY;
+		return ret;
+	}
+
+	list_move_tail(&cb->list, &dev->ctrl_rd_list);
+	cl->timer_count = MEI_CONNECT_TIMEOUT;
+	mei_schedule_stall_timer(dev);
+	return 0;
+}
+
+/**
+ * mei_cl_irq_connect - send connect request in irq_thread context
+ *
+ * @cl: host client
+ * @cb: callback block
+ * @cmpl_list: complete list
+ *
+ * Return: 0, OK; otherwise, error.
+ */
+int mei_cl_irq_connect(struct mei_cl *cl, struct mei_cl_cb *cb,
+		       struct list_head *cmpl_list)
+{
+	struct mei_device *dev = cl->dev;
+	u32 msg_slots;
+	int slots;
+	int rets;
+
+	if (mei_cl_is_other_connecting(cl))
+		return 0;
+
+	msg_slots = mei_hbm2slots(sizeof(struct hbm_client_connect_request));
+	slots = mei_hbuf_empty_slots(dev);
+	if (slots < 0)
+		return -EOVERFLOW;
+
+	if ((u32)slots < msg_slots)
+		return -EMSGSIZE;
+
+	rets = mei_cl_send_connect(cl, cb);
+	if (rets)
+		list_move_tail(&cb->list, cmpl_list);
+
+	return rets;
+}
+
+/**
+ * mei_cl_connect - connect host client to the me one
+ *
+ * @cl: host client
+ * @me_cl: me client
+ * @fp: pointer to file structure
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * Return: 0 on success, <0 on failure.
+ */
+int mei_cl_connect(struct mei_cl *cl, struct mei_me_client *me_cl,
+		   const struct file *fp)
+{
+	struct mei_device *dev;
+	struct mei_cl_cb *cb;
+	int rets;
+
+	if (WARN_ON(!cl || !cl->dev || !me_cl))
+		return -ENODEV;
+
+	dev = cl->dev;
+
+	rets = mei_cl_set_connecting(cl, me_cl);
+	if (rets)
+		goto nortpm;
+
+	if (mei_cl_is_fixed_address(cl)) {
+		cl->state = MEI_FILE_CONNECTED;
+		rets = 0;
+		goto nortpm;
+	}
+
+	rets = pm_runtime_get(dev->dev);
+	if (rets < 0 && rets != -EINPROGRESS) {
+		pm_runtime_put_noidle(dev->dev);
+		cl_err(dev, cl, "rpm: get failed %d\n", rets);
+		goto nortpm;
+	}
+
+	cb = mei_cl_enqueue_ctrl_wr_cb(cl, 0, MEI_FOP_CONNECT, fp);
+	if (!cb) {
+		rets = -ENOMEM;
+		goto out;
+	}
+
+	/* run hbuf acquire last so we don't have to undo */
+	if (!mei_cl_is_other_connecting(cl) && mei_hbuf_acquire(dev)) {
+		rets = mei_cl_send_connect(cl, cb);
+		if (rets)
+			goto out;
+	}
+
+	mutex_unlock(&dev->device_lock);
+	wait_event_timeout(cl->wait,
+			(cl->state == MEI_FILE_CONNECTED ||
+			 cl->state == MEI_FILE_DISCONNECTED ||
+			 cl->state == MEI_FILE_DISCONNECT_REQUIRED ||
+			 cl->state == MEI_FILE_DISCONNECT_REPLY),
+			mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT));
+	mutex_lock(&dev->device_lock);
+
+	if (!mei_cl_is_connected(cl)) {
+		if (cl->state == MEI_FILE_DISCONNECT_REQUIRED) {
+			mei_io_list_flush_cl(&dev->ctrl_rd_list, cl);
+			mei_io_list_flush_cl(&dev->ctrl_wr_list, cl);
+			 /* ignore disconnect return valuue;
+			  * in case of failure reset will be invoked
+			  */
+			__mei_cl_disconnect(cl);
+			rets = -EFAULT;
+			goto out;
+		}
+
+		/* timeout or something went really wrong */
+		if (!cl->status)
+			cl->status = -EFAULT;
+	}
+
+	rets = cl->status;
+out:
+	cl_dbg(dev, cl, "rpm: autosuspend\n");
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
+
+	mei_io_cb_free(cb);
+
+nortpm:
+	if (!mei_cl_is_connected(cl))
+		mei_cl_set_disconnected(cl);
+
+	return rets;
+}
+
+/**
+ * mei_cl_alloc_linked - allocate and link host client
+ *
+ * @dev: the device structure
+ *
+ * Return: cl on success ERR_PTR on failure
+ */
+struct mei_cl *mei_cl_alloc_linked(struct mei_device *dev)
+{
+	struct mei_cl *cl;
+	int ret;
+
+	cl = mei_cl_allocate(dev);
+	if (!cl) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	ret = mei_cl_link(cl);
+	if (ret)
+		goto err;
+
+	return cl;
+err:
+	kfree(cl);
+	return ERR_PTR(ret);
+}
+
+/**
+ * mei_cl_tx_flow_ctrl_creds - checks flow_control credits for cl.
+ *
+ * @cl: host client
+ *
+ * Return: 1 if tx_flow_ctrl_creds >0, 0 - otherwise.
+ */
+static int mei_cl_tx_flow_ctrl_creds(struct mei_cl *cl)
+{
+	if (WARN_ON(!cl || !cl->me_cl))
+		return -EINVAL;
+
+	if (cl->tx_flow_ctrl_creds > 0)
+		return 1;
+
+	if (mei_cl_is_fixed_address(cl))
+		return 1;
+
+	if (mei_cl_is_single_recv_buf(cl)) {
+		if (cl->me_cl->tx_flow_ctrl_creds > 0)
+			return 1;
+	}
+	return 0;
+}
+
+/**
+ * mei_cl_tx_flow_ctrl_creds_reduce - reduces transmit flow control credits
+ *   for a client
+ *
+ * @cl: host client
+ *
+ * Return:
+ *	0 on success
+ *	-EINVAL when ctrl credits are <= 0
+ */
+static int mei_cl_tx_flow_ctrl_creds_reduce(struct mei_cl *cl)
+{
+	if (WARN_ON(!cl || !cl->me_cl))
+		return -EINVAL;
+
+	if (mei_cl_is_fixed_address(cl))
+		return 0;
+
+	if (mei_cl_is_single_recv_buf(cl)) {
+		if (WARN_ON(cl->me_cl->tx_flow_ctrl_creds <= 0))
+			return -EINVAL;
+		cl->me_cl->tx_flow_ctrl_creds--;
+	} else {
+		if (WARN_ON(cl->tx_flow_ctrl_creds <= 0))
+			return -EINVAL;
+		cl->tx_flow_ctrl_creds--;
+	}
+	return 0;
+}
+
+/**
+ *  mei_cl_notify_fop2req - convert fop to proper request
+ *
+ * @fop: client notification start response command
+ *
+ * Return:  MEI_HBM_NOTIFICATION_START/STOP
+ */
+u8 mei_cl_notify_fop2req(enum mei_cb_file_ops fop)
+{
+	if (fop == MEI_FOP_NOTIFY_START)
+		return MEI_HBM_NOTIFICATION_START;
+	else
+		return MEI_HBM_NOTIFICATION_STOP;
+}
+
+/**
+ *  mei_cl_notify_req2fop - convert notification request top file operation type
+ *
+ * @req: hbm notification request type
+ *
+ * Return:  MEI_FOP_NOTIFY_START/STOP
+ */
+enum mei_cb_file_ops mei_cl_notify_req2fop(u8 req)
+{
+	if (req == MEI_HBM_NOTIFICATION_START)
+		return MEI_FOP_NOTIFY_START;
+	else
+		return MEI_FOP_NOTIFY_STOP;
+}
+
+/**
+ * mei_cl_irq_notify - send notification request in irq_thread context
+ *
+ * @cl: client
+ * @cb: callback block.
+ * @cmpl_list: complete list.
+ *
+ * Return: 0 on such and error otherwise.
+ */
+int mei_cl_irq_notify(struct mei_cl *cl, struct mei_cl_cb *cb,
+		      struct list_head *cmpl_list)
+{
+	struct mei_device *dev = cl->dev;
+	u32 msg_slots;
+	int slots;
+	int ret;
+	bool request;
+
+	msg_slots = mei_hbm2slots(sizeof(struct hbm_client_connect_request));
+	slots = mei_hbuf_empty_slots(dev);
+	if (slots < 0)
+		return -EOVERFLOW;
+
+	if ((u32)slots < msg_slots)
+		return -EMSGSIZE;
+
+	request = mei_cl_notify_fop2req(cb->fop_type);
+	ret = mei_hbm_cl_notify_req(dev, cl, request);
+	if (ret) {
+		cl->status = ret;
+		list_move_tail(&cb->list, cmpl_list);
+		return ret;
+	}
+
+	list_move_tail(&cb->list, &dev->ctrl_rd_list);
+	return 0;
+}
+
+/**
+ * mei_cl_notify_request - send notification stop/start request
+ *
+ * @cl: host client
+ * @fp: associate request with file
+ * @request: 1 for start or 0 for stop
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * Return: 0 on such and error otherwise.
+ */
+int mei_cl_notify_request(struct mei_cl *cl,
+			  const struct file *fp, u8 request)
+{
+	struct mei_device *dev;
+	struct mei_cl_cb *cb;
+	enum mei_cb_file_ops fop_type;
+	int rets;
+
+	if (WARN_ON(!cl || !cl->dev))
+		return -ENODEV;
+
+	dev = cl->dev;
+
+	if (!dev->hbm_f_ev_supported) {
+		cl_dbg(dev, cl, "notifications not supported\n");
+		return -EOPNOTSUPP;
+	}
+
+	if (!mei_cl_is_connected(cl))
+		return -ENODEV;
+
+	rets = pm_runtime_get(dev->dev);
+	if (rets < 0 && rets != -EINPROGRESS) {
+		pm_runtime_put_noidle(dev->dev);
+		cl_err(dev, cl, "rpm: get failed %d\n", rets);
+		return rets;
+	}
+
+	fop_type = mei_cl_notify_req2fop(request);
+	cb = mei_cl_enqueue_ctrl_wr_cb(cl, 0, fop_type, fp);
+	if (!cb) {
+		rets = -ENOMEM;
+		goto out;
+	}
+
+	if (mei_hbuf_acquire(dev)) {
+		if (mei_hbm_cl_notify_req(dev, cl, request)) {
+			rets = -ENODEV;
+			goto out;
+		}
+		list_move_tail(&cb->list, &dev->ctrl_rd_list);
+	}
+
+	mutex_unlock(&dev->device_lock);
+	wait_event_timeout(cl->wait,
+			   cl->notify_en == request || !mei_cl_is_connected(cl),
+			   mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT));
+	mutex_lock(&dev->device_lock);
+
+	if (cl->notify_en != request && !cl->status)
+		cl->status = -EFAULT;
+
+	rets = cl->status;
+
+out:
+	cl_dbg(dev, cl, "rpm: autosuspend\n");
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
+
+	mei_io_cb_free(cb);
+	return rets;
+}
+
+/**
+ * mei_cl_notify - raise notification
+ *
+ * @cl: host client
+ *
+ * Locking: called under "dev->device_lock" lock
+ */
+void mei_cl_notify(struct mei_cl *cl)
+{
+	struct mei_device *dev;
+
+	if (!cl || !cl->dev)
+		return;
+
+	dev = cl->dev;
+
+	if (!cl->notify_en)
+		return;
+
+	cl_dbg(dev, cl, "notify event");
+	cl->notify_ev = true;
+	if (!mei_cl_bus_notify_event(cl))
+		wake_up_interruptible(&cl->ev_wait);
+
+	if (cl->ev_async)
+		kill_fasync(&cl->ev_async, SIGIO, POLL_PRI);
+
+}
+
+/**
+ * mei_cl_notify_get - get or wait for notification event
+ *
+ * @cl: host client
+ * @block: this request is blocking
+ * @notify_ev: true if notification event was received
+ *
+ * Locking: called under "dev->device_lock" lock
+ *
+ * Return: 0 on such and error otherwise.
+ */
+int mei_cl_notify_get(struct mei_cl *cl, bool block, bool *notify_ev)
+{
+	struct mei_device *dev;
+	int rets;
+
+	*notify_ev = false;
+
+	if (WARN_ON(!cl || !cl->dev))
+		return -ENODEV;
+
+	dev = cl->dev;
+
+	if (!dev->hbm_f_ev_supported) {
+		cl_dbg(dev, cl, "notifications not supported\n");
+		return -EOPNOTSUPP;
+	}
+
+	if (!mei_cl_is_connected(cl))
+		return -ENODEV;
+
+	if (cl->notify_ev)
+		goto out;
+
+	if (!block)
+		return -EAGAIN;
+
+	mutex_unlock(&dev->device_lock);
+	rets = wait_event_interruptible(cl->ev_wait, cl->notify_ev);
+	mutex_lock(&dev->device_lock);
+
+	if (rets < 0)
+		return rets;
+
+out:
+	*notify_ev = cl->notify_ev;
+	cl->notify_ev = false;
+	return 0;
+}
+
+/**
+ * mei_cl_read_start - the start read client message function.
+ *
+ * @cl: host client
+ * @length: number of bytes to read
+ * @fp: pointer to file structure
+ *
+ * Return: 0 on success, <0 on failure.
+ */
+int mei_cl_read_start(struct mei_cl *cl, size_t length, const struct file *fp)
+{
+	struct mei_device *dev;
+	struct mei_cl_cb *cb;
+	int rets;
+
+	if (WARN_ON(!cl || !cl->dev))
+		return -ENODEV;
+
+	dev = cl->dev;
+
+	if (!mei_cl_is_connected(cl))
+		return -ENODEV;
+
+	if (!mei_me_cl_is_active(cl->me_cl)) {
+		cl_err(dev, cl, "no such me client\n");
+		return  -ENOTTY;
+	}
+
+	if (mei_cl_is_fixed_address(cl))
+		return 0;
+
+	/* HW currently supports only one pending read */
+	if (cl->rx_flow_ctrl_creds)
+		return -EBUSY;
+
+	cb = mei_cl_enqueue_ctrl_wr_cb(cl, length, MEI_FOP_READ, fp);
+	if (!cb)
+		return -ENOMEM;
+
+	rets = pm_runtime_get(dev->dev);
+	if (rets < 0 && rets != -EINPROGRESS) {
+		pm_runtime_put_noidle(dev->dev);
+		cl_err(dev, cl, "rpm: get failed %d\n", rets);
+		goto nortpm;
+	}
+
+	rets = 0;
+	if (mei_hbuf_acquire(dev)) {
+		rets = mei_hbm_cl_flow_control_req(dev, cl);
+		if (rets < 0)
+			goto out;
+
+		list_move_tail(&cb->list, &cl->rd_pending);
+	}
+	cl->rx_flow_ctrl_creds++;
+
+out:
+	cl_dbg(dev, cl, "rpm: autosuspend\n");
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
+nortpm:
+	if (rets)
+		mei_io_cb_free(cb);
+
+	return rets;
+}
+
+/**
+ * mei_msg_hdr_init - initialize mei message header
+ *
+ * @mei_hdr: mei message header
+ * @cb: message callback structure
+ */
+static void mei_msg_hdr_init(struct mei_msg_hdr *mei_hdr, struct mei_cl_cb *cb)
+{
+	mei_hdr->host_addr = mei_cl_host_addr(cb->cl);
+	mei_hdr->me_addr = mei_cl_me_id(cb->cl);
+	mei_hdr->length = 0;
+	mei_hdr->reserved = 0;
+	mei_hdr->msg_complete = 0;
+	mei_hdr->dma_ring = 0;
+	mei_hdr->internal = cb->internal;
+}
+
+/**
+ * mei_cl_irq_write - write a message to device
+ *	from the interrupt thread context
+ *
+ * @cl: client
+ * @cb: callback block.
+ * @cmpl_list: complete list.
+ *
+ * Return: 0, OK; otherwise error.
+ */
+int mei_cl_irq_write(struct mei_cl *cl, struct mei_cl_cb *cb,
+		     struct list_head *cmpl_list)
+{
+	struct mei_device *dev;
+	struct mei_msg_data *buf;
+	struct mei_msg_hdr mei_hdr;
+	size_t hdr_len = sizeof(mei_hdr);
+	size_t len;
+	size_t hbuf_len;
+	int hbuf_slots;
+	int rets;
+	bool first_chunk;
+
+	if (WARN_ON(!cl || !cl->dev))
+		return -ENODEV;
+
+	dev = cl->dev;
+
+	buf = &cb->buf;
+
+	first_chunk = cb->buf_idx == 0;
+
+	rets = first_chunk ? mei_cl_tx_flow_ctrl_creds(cl) : 1;
+	if (rets < 0)
+		goto err;
+
+	if (rets == 0) {
+		cl_dbg(dev, cl, "No flow control credentials: not sending.\n");
+		return 0;
+	}
+
+	len = buf->size - cb->buf_idx;
+	hbuf_slots = mei_hbuf_empty_slots(dev);
+	if (hbuf_slots < 0) {
+		rets = -EOVERFLOW;
+		goto err;
+	}
+
+	hbuf_len = mei_slots2data(hbuf_slots);
+
+	mei_msg_hdr_init(&mei_hdr, cb);
+
+	/**
+	 * Split the message only if we can write the whole host buffer
+	 * otherwise wait for next time the host buffer is empty.
+	 */
+	if (len + hdr_len <= hbuf_len) {
+		mei_hdr.length = len;
+		mei_hdr.msg_complete = 1;
+	} else if ((u32)hbuf_slots == mei_hbuf_depth(dev)) {
+		mei_hdr.length = hbuf_len - hdr_len;
+	} else {
+		return 0;
+	}
+
+	cl_dbg(dev, cl, "buf: size = %zu idx = %zu\n",
+			cb->buf.size, cb->buf_idx);
+
+	rets = mei_write_message(dev, &mei_hdr, hdr_len,
+				 buf->data + cb->buf_idx, mei_hdr.length);
+	if (rets)
+		goto err;
+
+	cl->status = 0;
+	cl->writing_state = MEI_WRITING;
+	cb->buf_idx += mei_hdr.length;
+
+	if (first_chunk) {
+		if (mei_cl_tx_flow_ctrl_creds_reduce(cl)) {
+			rets = -EIO;
+			goto err;
+		}
+	}
+
+	if (mei_hdr.msg_complete)
+		list_move_tail(&cb->list, &dev->write_waiting_list);
+
+	return 0;
+
+err:
+	cl->status = rets;
+	list_move_tail(&cb->list, cmpl_list);
+	return rets;
+}
+
+/**
+ * mei_cl_write - submit a write cb to mei device
+ *	assumes device_lock is locked
+ *
+ * @cl: host client
+ * @cb: write callback with filled data
+ *
+ * Return: number of bytes sent on success, <0 on failure.
+ */
+ssize_t mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb)
+{
+	struct mei_device *dev;
+	struct mei_msg_data *buf;
+	struct mei_msg_hdr mei_hdr;
+	size_t hdr_len = sizeof(mei_hdr);
+	size_t len;
+	size_t hbuf_len;
+	int hbuf_slots;
+	ssize_t rets;
+	bool blocking;
+
+	if (WARN_ON(!cl || !cl->dev))
+		return -ENODEV;
+
+	if (WARN_ON(!cb))
+		return -EINVAL;
+
+	dev = cl->dev;
+
+	buf = &cb->buf;
+	len = buf->size;
+	blocking = cb->blocking;
+
+	cl_dbg(dev, cl, "len=%zd\n", len);
+
+	rets = pm_runtime_get(dev->dev);
+	if (rets < 0 && rets != -EINPROGRESS) {
+		pm_runtime_put_noidle(dev->dev);
+		cl_err(dev, cl, "rpm: get failed %zd\n", rets);
+		goto free;
+	}
+
+	cb->buf_idx = 0;
+	cl->writing_state = MEI_IDLE;
+
+
+	rets = mei_cl_tx_flow_ctrl_creds(cl);
+	if (rets < 0)
+		goto err;
+
+	mei_msg_hdr_init(&mei_hdr, cb);
+
+	if (rets == 0) {
+		cl_dbg(dev, cl, "No flow control credentials: not sending.\n");
+		rets = len;
+		goto out;
+	}
+
+	if (!mei_hbuf_acquire(dev)) {
+		cl_dbg(dev, cl, "Cannot acquire the host buffer: not sending.\n");
+		rets = len;
+		goto out;
+	}
+
+	hbuf_slots = mei_hbuf_empty_slots(dev);
+	if (hbuf_slots < 0) {
+		rets = -EOVERFLOW;
+		goto out;
+	}
+
+	hbuf_len = mei_slots2data(hbuf_slots);
+
+	if (len + hdr_len <= hbuf_len) {
+		mei_hdr.length = len;
+		mei_hdr.msg_complete = 1;
+	} else {
+		mei_hdr.length = hbuf_len - hdr_len;
+	}
+
+	rets = mei_write_message(dev, &mei_hdr, hdr_len,
+				 buf->data, mei_hdr.length);
+	if (rets)
+		goto err;
+
+	rets = mei_cl_tx_flow_ctrl_creds_reduce(cl);
+	if (rets)
+		goto err;
+
+	cl->writing_state = MEI_WRITING;
+	cb->buf_idx = mei_hdr.length;
+
+out:
+	if (mei_hdr.msg_complete)
+		mei_tx_cb_enqueue(cb, &dev->write_waiting_list);
+	else
+		mei_tx_cb_enqueue(cb, &dev->write_list);
+
+	cb = NULL;
+	if (blocking && cl->writing_state != MEI_WRITE_COMPLETE) {
+
+		mutex_unlock(&dev->device_lock);
+		rets = wait_event_interruptible(cl->tx_wait,
+				cl->writing_state == MEI_WRITE_COMPLETE ||
+				(!mei_cl_is_connected(cl)));
+		mutex_lock(&dev->device_lock);
+		/* wait_event_interruptible returns -ERESTARTSYS */
+		if (rets) {
+			if (signal_pending(current))
+				rets = -EINTR;
+			goto err;
+		}
+		if (cl->writing_state != MEI_WRITE_COMPLETE) {
+			rets = -EFAULT;
+			goto err;
+		}
+	}
+
+	rets = len;
+err:
+	cl_dbg(dev, cl, "rpm: autosuspend\n");
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
+free:
+	mei_io_cb_free(cb);
+
+	return rets;
+}
+
+
+/**
+ * mei_cl_complete - processes completed operation for a client
+ *
+ * @cl: private data of the file object.
+ * @cb: callback block.
+ */
+void mei_cl_complete(struct mei_cl *cl, struct mei_cl_cb *cb)
+{
+	struct mei_device *dev = cl->dev;
+
+	switch (cb->fop_type) {
+	case MEI_FOP_WRITE:
+		mei_tx_cb_dequeue(cb);
+		cl->writing_state = MEI_WRITE_COMPLETE;
+		if (waitqueue_active(&cl->tx_wait)) {
+			wake_up_interruptible(&cl->tx_wait);
+		} else {
+			pm_runtime_mark_last_busy(dev->dev);
+			pm_request_autosuspend(dev->dev);
+		}
+		break;
+
+	case MEI_FOP_READ:
+		list_add_tail(&cb->list, &cl->rd_completed);
+		if (!mei_cl_is_fixed_address(cl) &&
+		    !WARN_ON(!cl->rx_flow_ctrl_creds))
+			cl->rx_flow_ctrl_creds--;
+		if (!mei_cl_bus_rx_event(cl))
+			wake_up_interruptible(&cl->rx_wait);
+		break;
+
+	case MEI_FOP_CONNECT:
+	case MEI_FOP_DISCONNECT:
+	case MEI_FOP_NOTIFY_STOP:
+	case MEI_FOP_NOTIFY_START:
+		if (waitqueue_active(&cl->wait))
+			wake_up(&cl->wait);
+
+		break;
+	case MEI_FOP_DISCONNECT_RSP:
+		mei_io_cb_free(cb);
+		mei_cl_set_disconnected(cl);
+		break;
+	default:
+		BUG_ON(0);
+	}
+}
+
+
+/**
+ * mei_cl_all_disconnect - disconnect forcefully all connected clients
+ *
+ * @dev: mei device
+ */
+void mei_cl_all_disconnect(struct mei_device *dev)
+{
+	struct mei_cl *cl;
+
+	list_for_each_entry(cl, &dev->file_list, link)
+		mei_cl_set_disconnected(cl);
+}