/*
 *
 * 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/pci.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/delay.h>

#include <linux/mei.h>

#include "mei_dev.h"
#include "hbm.h"
#include "client.h"

/**
 * mei_me_cl_by_uuid - locate index of me client
 *
 * @dev: mei device
 *
 * Locking: called under "dev->device_lock" lock
 *
 * returns me client index or -ENOENT if not found
 */
int mei_me_cl_by_uuid(const struct mei_device *dev, const uuid_le *uuid)
{
        int i;

        for (i = 0; i < dev->me_clients_num; ++i)
                if (uuid_le_cmp(*uuid,
                                dev->me_clients[i].props.protocol_name) == 0)
                        return i;

        return -ENOENT;
}


/**
 * mei_me_cl_by_id return index to me_clients for client_id
 *
 * @dev: the device structure
 * @client_id: me client id
 *
 * Locking: called under "dev->device_lock" lock
 *
 * returns index on success, -ENOENT on failure.
 */

int mei_me_cl_by_id(struct mei_device *dev, u8 client_id)
{
        int i;

        for (i = 0; i < dev->me_clients_num; i++)
                if (dev->me_clients[i].client_id == client_id)
                        return i;

        return -ENOENT;
}


/**
 * mei_cl_cmp_id - tells if the clients are the same
 *
 * @cl1: host client 1
 * @cl2: host client 2
 *
 * returns 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) &&
                (cl1->me_client_id == cl2->me_client_id);
}

/**
 * mei_io_list_flush - removes cbs belonging to cl.
 *
 * @list:  an instance of our list structure
 * @cl:    host client, can be NULL for flushing the whole list
 * @free:  whether to free the cbs
 */
static void __mei_io_list_flush(struct mei_cl_cb *list,
                                struct mei_cl *cl, bool free)
{
        struct mei_cl_cb *cb;
        struct mei_cl_cb *next;

        /* enable removing everything if no cl is specified */
        list_for_each_entry_safe(cb, next, &list->list, list) {
                if (!cl || (cb->cl && mei_cl_cmp_id(cl, cb->cl))) {
                        list_del(&cb->list);
                        if (free)
                                mei_io_cb_free(cb);
                }
        }
}

/**
 * mei_io_list_flush - removes list entry belonging to cl.
 *
 * @list:  An instance of our list structure
 * @cl: host client
 */
static inline void mei_io_list_flush(struct mei_cl_cb *list, struct mei_cl *cl)
{
        __mei_io_list_flush(list, cl, false);
}


/**
 * mei_io_list_free - removes cb belonging to cl and free them
 *
 * @list:  An instance of our list structure
 * @cl: host client
 */
static inline void mei_io_list_free(struct mei_cl_cb *list, struct mei_cl *cl)
{
        __mei_io_list_flush(list, cl, true);
}

/**
 * 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;

        kfree(cb->request_buffer.data);
        kfree(cb->response_buffer.data);
        kfree(cb);
}

/**
 * mei_io_cb_init - allocate and initialize io callback
 *
 * @cl - mei client
 * @fp: pointer to file structure
 *
 * returns mei_cl_cb pointer or NULL;
 */
struct mei_cl_cb *mei_io_cb_init(struct mei_cl *cl, struct file *fp)
{
        struct mei_cl_cb *cb;

        cb = kzalloc(sizeof(struct mei_cl_cb), GFP_KERNEL);
        if (!cb)
                return NULL;

        mei_io_list_init(cb);

        cb->file_object = fp;
        cb->cl = cl;
        cb->buf_idx = 0;
        return cb;
}

/**
 * mei_io_cb_alloc_req_buf - allocate request buffer
 *
 * @cb: io callback structure
 * @length: size of the buffer
 *
 * returns 0 on success
 *         -EINVAL if cb is NULL
 *         -ENOMEM if allocation failed
 */
int mei_io_cb_alloc_req_buf(struct mei_cl_cb *cb, size_t length)
{
        if (!cb)
                return -EINVAL;

        if (length == 0)
                return 0;

        cb->request_buffer.data = kmalloc(length, GFP_KERNEL);
        if (!cb->request_buffer.data)
                return -ENOMEM;
        cb->request_buffer.size = length;
        return 0;
}
/**
 * mei_io_cb_alloc_resp_buf - allocate response buffer
 *
 * @cb: io callback structure
 * @length: size of the buffer
 *
 * returns 0 on success
 *         -EINVAL if cb is NULL
 *         -ENOMEM if allocation failed
 */
int mei_io_cb_alloc_resp_buf(struct mei_cl_cb *cb, size_t length)
{
        if (!cb)
                return -EINVAL;

        if (length == 0)
                return 0;

        cb->response_buffer.data = kmalloc(length, GFP_KERNEL);
        if (!cb->response_buffer.data)
                return -ENOMEM;
        cb->response_buffer.size = length;
        return 0;
}



/**
 * mei_cl_flush_queues - flushes queue lists belonging to cl.
 *
 * @cl: host client
 */
int mei_cl_flush_queues(struct mei_cl *cl)
{
        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_list_flush(&cl->dev->read_list, cl);
        mei_io_list_free(&cl->dev->write_list, cl);
        mei_io_list_free(&cl->dev->write_waiting_list, cl);
        mei_io_list_flush(&cl->dev->ctrl_wr_list, cl);
        mei_io_list_flush(&cl->dev->ctrl_rd_list, cl);
        mei_io_list_flush(&cl->dev->amthif_cmd_list, cl);
        mei_io_list_flush(&cl->dev->amthif_rd_complete_list, cl);
        return 0;
}


/**
 * mei_cl_init - initializes cl.
 *
 * @cl: host client to be initialized
 * @dev: mei device
 */
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_LIST_HEAD(&cl->link);
        INIT_LIST_HEAD(&cl->device_link);
        cl->reading_state = MEI_IDLE;
        cl->writing_state = MEI_IDLE;
        cl->dev = dev;
}

/**
 * mei_cl_allocate - allocates cl  structure and sets it up.
 *
 * @dev: mei device
 * returns  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_find_read_cb - find this cl's callback in the read list
 *
 * @cl: host client
 *
 * returns cb on success, NULL on error
 */
struct mei_cl_cb *mei_cl_find_read_cb(struct mei_cl *cl)
{
        struct mei_device *dev = cl->dev;
        struct mei_cl_cb *cb;

        list_for_each_entry(cb, &dev->read_list.list, list)
                if (mei_cl_cmp_id(cl, cb->cl))
                        return cb;
        return NULL;
}

/** mei_cl_link: allocate host id in the host map
 *
 * @cl - host client
 * @id - fixed host id or -1 for generic one
 *
 * returns 0 on success
 *      -EINVAL on incorrect values
 *      -ENONET if client not found
 */
int mei_cl_link(struct mei_cl *cl, int id)
{
        struct mei_device *dev;
        long open_handle_count;

        if (WARN_ON(!cl || !cl->dev))
                return -EINVAL;

        dev = cl->dev;

        /* If Id is not assigned get one*/
        if (id == MEI_HOST_CLIENT_ID_ANY)
                id = find_first_zero_bit(dev->host_clients_map,
                                        MEI_CLIENTS_MAX);

        if (id >= MEI_CLIENTS_MAX) {
                dev_err(&dev->pdev->dev, "id exceeded %d", MEI_CLIENTS_MAX);
                return -EMFILE;
        }

        open_handle_count = dev->open_handle_count + dev->iamthif_open_count;
        if (open_handle_count >= MEI_MAX_OPEN_HANDLE_COUNT) {
                dev_err(&dev->pdev->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 me_cl from the list
 *
 * @cl: host client
 */
int mei_cl_unlink(struct mei_cl *cl)
{
        struct mei_device *dev;

        /* don't shout on error exit path */
        if (!cl)
                return 0;

        /* wd and amthif might not be initialized */
        if (!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_INITIALIZING;

        return 0;
}


void mei_host_client_init(struct work_struct *work)
{
        struct mei_device *dev = container_of(work,
                                              struct mei_device, init_work);
        struct mei_client_properties *client_props;
        int i;

        mutex_lock(&dev->device_lock);

        for (i = 0; i < dev->me_clients_num; i++) {
                client_props = &dev->me_clients[i].props;

                if (!uuid_le_cmp(client_props->protocol_name, mei_amthif_guid))
                        mei_amthif_host_init(dev);
                else if (!uuid_le_cmp(client_props->protocol_name, mei_wd_guid))
                        mei_wd_host_init(dev);
                else if (!uuid_le_cmp(client_props->protocol_name, mei_nfc_guid))
                        mei_nfc_host_init(dev);

        }

        dev->dev_state = MEI_DEV_ENABLED;
        dev->reset_count = 0;

        mutex_unlock(&dev->device_lock);
}

/**
 * mei_hbuf_acquire: try to acquire host buffer
 *
 * @dev: the device structure
 * returns true if host buffer was acquired
 */
bool mei_hbuf_acquire(struct mei_device *dev)
{
        if (!dev->hbuf_is_ready) {
                dev_dbg(&dev->pdev->dev, "hbuf is not ready\n");
                return false;
        }

        dev->hbuf_is_ready = false;

        return true;
}

/**
 * mei_cl_disconnect - disconnect host client from the me one
 *
 * @cl: host client
 *
 * Locking: called under "dev->device_lock" lock
 *
 * returns 0 on success, <0 on failure.
 */
int mei_cl_disconnect(struct mei_cl *cl)
{
        struct mei_device *dev;
        struct mei_cl_cb *cb;
        int rets, err;

        if (WARN_ON(!cl || !cl->dev))
                return -ENODEV;

        dev = cl->dev;

        cl_dbg(dev, cl, "disconnecting");

        if (cl->state != MEI_FILE_DISCONNECTING)
                return 0;

        cb = mei_io_cb_init(cl, NULL);
        if (!cb)
                return -ENOMEM;

        cb->fop_type = MEI_FOP_CLOSE;
        if (mei_hbuf_acquire(dev)) {
                if (mei_hbm_cl_disconnect_req(dev, cl)) {
                        rets = -ENODEV;
                        cl_err(dev, cl, "failed to disconnect.\n");
                        goto free;
                }
                mdelay(10); /* Wait for hardware disconnection ready */
                list_add_tail(&cb->list, &dev->ctrl_rd_list.list);
        } else {
                cl_dbg(dev, cl, "add disconnect cb to control write list\n");
                list_add_tail(&cb->list, &dev->ctrl_wr_list.list);

        }
        mutex_unlock(&dev->device_lock);

        err = wait_event_timeout(dev->wait_recvd_msg,
                        MEI_FILE_DISCONNECTED == cl->state,
                        mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT));

        mutex_lock(&dev->device_lock);
        if (MEI_FILE_DISCONNECTED == cl->state) {
                rets = 0;
                cl_dbg(dev, cl, "successfully disconnected from FW client.\n");
        } else {
                rets = -ENODEV;
                if (MEI_FILE_DISCONNECTED != cl->state)
                        cl_err(dev, cl, "wrong status client disconnect.\n");

                if (err)
                        cl_dbg(dev, cl, "wait failed disconnect err=%08x\n",
                                        err);

                cl_err(dev, cl, "failed to disconnect from FW client.\n");
        }

        mei_io_list_flush(&dev->ctrl_rd_list, cl);
        mei_io_list_flush(&dev->ctrl_wr_list, cl);
free:
        mei_io_cb_free(cb);
        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
 *
 * returns true if other client is connected, false - otherwise.
 */
bool mei_cl_is_other_connecting(struct mei_cl *cl)
{
        struct mei_device *dev;
        struct mei_cl *ocl; /* the other client */

        if (WARN_ON(!cl || !cl->dev))
                return false;

        dev = cl->dev;

        list_for_each_entry(ocl, &dev->file_list, link) {
                if (ocl->state == MEI_FILE_CONNECTING &&
                    ocl != cl &&
                    cl->me_client_id == ocl->me_client_id)
                        return true;

        }

        return false;
}

/**
 * mei_cl_connect - connect host client to the me one
 *
 * @cl: host client
 *
 * Locking: called under "dev->device_lock" lock
 *
 * returns 0 on success, <0 on failure.
 */
int mei_cl_connect(struct mei_cl *cl, struct file *file)
{
        struct mei_device *dev;
        struct mei_cl_cb *cb;
        int rets;

        if (WARN_ON(!cl || !cl->dev))
                return -ENODEV;

        dev = cl->dev;

        cb = mei_io_cb_init(cl, file);
        if (!cb) {
                rets = -ENOMEM;
                goto out;
        }

        cb->fop_type = MEI_FOP_CONNECT;

        /* run hbuf acquire last so we don't have to undo */
        if (!mei_cl_is_other_connecting(cl) && mei_hbuf_acquire(dev)) {
                if (mei_hbm_cl_connect_req(dev, cl)) {
                        rets = -ENODEV;
                        goto out;
                }
                cl->timer_count = MEI_CONNECT_TIMEOUT;
                list_add_tail(&cb->list, &dev->ctrl_rd_list.list);
        } else {
                list_add_tail(&cb->list, &dev->ctrl_wr_list.list);
        }

        mutex_unlock(&dev->device_lock);
        wait_event_timeout(dev->wait_recvd_msg,
                        (cl->state == MEI_FILE_CONNECTED ||
                         cl->state == MEI_FILE_DISCONNECTED),
                        mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT));
        mutex_lock(&dev->device_lock);

        if (cl->state != MEI_FILE_CONNECTED) {
                /* something went really wrong */
                if (!cl->status)
                        cl->status = -EFAULT;

                mei_io_list_flush(&dev->ctrl_rd_list, cl);
                mei_io_list_flush(&dev->ctrl_wr_list, cl);
        }

        rets = cl->status;

out:
        mei_io_cb_free(cb);
        return rets;
}

/**
 * mei_cl_flow_ctrl_creds - checks flow_control credits for cl.
 *
 * @cl: private data of the file object
 *
 * returns 1 if mei_flow_ctrl_creds >0, 0 - otherwise.
 *      -ENOENT if mei_cl is not present
 *      -EINVAL if single_recv_buf == 0
 */
int mei_cl_flow_ctrl_creds(struct mei_cl *cl)
{
        struct mei_device *dev;
        struct mei_me_client *me_cl;
        int id;

        if (WARN_ON(!cl || !cl->dev))
                return -EINVAL;

        dev = cl->dev;

        if (!dev->me_clients_num)
                return 0;

        if (cl->mei_flow_ctrl_creds > 0)
                return 1;

        id = mei_me_cl_by_id(dev, cl->me_client_id);
        if (id < 0) {
                cl_err(dev, cl, "no such me client %d\n", cl->me_client_id);
                return id;
        }

        me_cl = &dev->me_clients[id];
        if (me_cl->mei_flow_ctrl_creds) {
                if (WARN_ON(me_cl->props.single_recv_buf == 0))
                        return -EINVAL;
                return 1;
        }
        return 0;
}

/**
 * mei_cl_flow_ctrl_reduce - reduces flow_control.
 *
 * @cl: private data of the file object
 *
 * @returns
 *      0 on success
 *      -ENOENT when me client is not found
 *      -EINVAL when ctrl credits are <= 0
 */
int mei_cl_flow_ctrl_reduce(struct mei_cl *cl)
{
        struct mei_device *dev;
        struct mei_me_client *me_cl;
        int id;

        if (WARN_ON(!cl || !cl->dev))
                return -EINVAL;

        dev = cl->dev;

        id = mei_me_cl_by_id(dev, cl->me_client_id);
        if (id < 0) {
                cl_err(dev, cl, "no such me client %d\n", cl->me_client_id);
                return id;
        }

        me_cl = &dev->me_clients[id];
        if (me_cl->props.single_recv_buf != 0) {
                if (WARN_ON(me_cl->mei_flow_ctrl_creds <= 0))
                        return -EINVAL;
                me_cl->mei_flow_ctrl_creds--;
        } else {
                if (WARN_ON(cl->mei_flow_ctrl_creds <= 0))
                        return -EINVAL;
                cl->mei_flow_ctrl_creds--;
        }
        return 0;
}

/**
 * mei_cl_read_start - the start read client message function.
 *
 * @cl: host client
 *
 * returns 0 on success, <0 on failure.
 */
int mei_cl_read_start(struct mei_cl *cl, size_t length)
{
        struct mei_device *dev;
        struct mei_cl_cb *cb;
        int rets;
        int i;

        if (WARN_ON(!cl || !cl->dev))
                return -ENODEV;

        dev = cl->dev;

        if (!mei_cl_is_connected(cl))
                return -ENODEV;

        if (cl->read_cb) {
                cl_dbg(dev, cl, "read is pending.\n");
                return -EBUSY;
        }
        i = mei_me_cl_by_id(dev, cl->me_client_id);
        if (i < 0) {
                cl_err(dev, cl, "no such me client %d\n", cl->me_client_id);
                return  -ENOTTY;
        }

        cb = mei_io_cb_init(cl, NULL);
        if (!cb)
                return -ENOMEM;

        /* always allocate at least client max message */
        length = max_t(size_t, length, dev->me_clients[i].props.max_msg_length);
        rets = mei_io_cb_alloc_resp_buf(cb, length);
        if (rets)
                goto err;

        cb->fop_type = MEI_FOP_READ;
        if (mei_hbuf_acquire(dev)) {
                if (mei_hbm_cl_flow_control_req(dev, cl)) {
                        cl_err(dev, cl, "flow control send failed\n");
                        rets = -ENODEV;
                        goto err;
                }
                list_add_tail(&cb->list, &dev->read_list.list);
        } else {
                list_add_tail(&cb->list, &dev->ctrl_wr_list.list);
        }

        cl->read_cb = cb;

        return rets;
err:
        mei_io_cb_free(cb);
        return rets;
}

/**
 * mei_cl_irq_write - write a message to device
 *      from the interrupt thread context
 *
 * @cl: client
 * @cb: callback block.
 * @cmpl_list: complete list.
 *
 * returns 0, OK; otherwise error.
 */
int mei_cl_irq_write(struct mei_cl *cl, struct mei_cl_cb *cb,
                     struct mei_cl_cb *cmpl_list)
{
        struct mei_device *dev;
        struct mei_msg_data *buf;
        struct mei_msg_hdr mei_hdr;
        size_t len;
        u32 msg_slots;
        int slots;
        int rets;

        if (WARN_ON(!cl || !cl->dev))
                return -ENODEV;

        dev = cl->dev;

        buf = &cb->request_buffer;

        rets = mei_cl_flow_ctrl_creds(cl);
        if (rets < 0)
                return rets;

        if (rets == 0) {
                cl_dbg(dev, cl, "No flow control credentials: not sending.\n");
                return 0;
        }

        slots = mei_hbuf_empty_slots(dev);
        len = buf->size - cb->buf_idx;
        msg_slots = mei_data2slots(len);

        mei_hdr.host_addr = cl->host_client_id;
        mei_hdr.me_addr = cl->me_client_id;
        mei_hdr.reserved = 0;
        mei_hdr.internal = cb->internal;

        if (slots >= msg_slots) {
                mei_hdr.length = len;
                mei_hdr.msg_complete = 1;
        /* Split the message only if we can write the whole host buffer */
        } else if (slots == dev->hbuf_depth) {
                msg_slots = slots;
                len = (slots * sizeof(u32)) - sizeof(struct mei_msg_hdr);
                mei_hdr.length = len;
                mei_hdr.msg_complete = 0;
        } else {
                /* wait for next time the host buffer is empty */
                return 0;
        }

        cl_dbg(dev, cl, "buf: size = %d idx = %lu\n",
                        cb->request_buffer.size, cb->buf_idx);

        rets = mei_write_message(dev, &mei_hdr, buf->data + cb->buf_idx);
        if (rets) {
                cl->status = rets;
                list_move_tail(&cb->list, &cmpl_list->list);
                return rets;
        }

        cl->status = 0;
        cl->writing_state = MEI_WRITING;
        cb->buf_idx += mei_hdr.length;

        if (mei_hdr.msg_complete) {
                if (mei_cl_flow_ctrl_reduce(cl))
                        return -EIO;
                list_move_tail(&cb->list, &dev->write_waiting_list.list);
        }

        return 0;
}

/**
 * mei_cl_write - submit a write cb to mei device
        assumes device_lock is locked
 *
 * @cl: host client
 * @cl: write callback with filled data
 *
 * returns number of bytes sent on success, <0 on failure.
 */
int mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb, bool blocking)
{
        struct mei_device *dev;
        struct mei_msg_data *buf;
        struct mei_msg_hdr mei_hdr;
        int rets;


        if (WARN_ON(!cl || !cl->dev))
                return -ENODEV;

        if (WARN_ON(!cb))
                return -EINVAL;

        dev = cl->dev;


        buf = &cb->request_buffer;

        cl_dbg(dev, cl, "mei_cl_write %d\n", buf->size);


        cb->fop_type = MEI_FOP_WRITE;
        cb->buf_idx = 0;
        cl->writing_state = MEI_IDLE;

        mei_hdr.host_addr = cl->host_client_id;
        mei_hdr.me_addr = cl->me_client_id;
        mei_hdr.reserved = 0;
        mei_hdr.msg_complete = 0;
        mei_hdr.internal = cb->internal;

        rets = mei_cl_flow_ctrl_creds(cl);
        if (rets < 0)
                goto err;

        if (rets == 0) {
                cl_dbg(dev, cl, "No flow control credentials: not sending.\n");
                rets = buf->size;
                goto out;
        }
        if (!mei_hbuf_acquire(dev)) {
                cl_dbg(dev, cl, "Cannot acquire the host buffer: not sending.\n");
                rets = buf->size;
                goto out;
        }

        /* Check for a maximum length */
        if (buf->size > mei_hbuf_max_len(dev)) {
                mei_hdr.length = mei_hbuf_max_len(dev);
                mei_hdr.msg_complete = 0;
        } else {
                mei_hdr.length = buf->size;
                mei_hdr.msg_complete = 1;
        }

        rets = mei_write_message(dev, &mei_hdr, buf->data);
        if (rets)
                goto err;

        cl->writing_state = MEI_WRITING;
        cb->buf_idx = mei_hdr.length;

out:
        if (mei_hdr.msg_complete) {
                rets = mei_cl_flow_ctrl_reduce(cl);
                if (rets < 0)
                        goto err;

                list_add_tail(&cb->list, &dev->write_waiting_list.list);
        } else {
                list_add_tail(&cb->list, &dev->write_list.list);
        }


        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);
                mutex_lock(&dev->device_lock);
                /* wait_event_interruptible returns -ERESTARTSYS */
                if (rets) {
                        if (signal_pending(current))
                                rets = -EINTR;
                        goto err;
                }
        }

        rets = buf->size;
err:
        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)
{
        if (cb->fop_type == MEI_FOP_WRITE) {
                mei_io_cb_free(cb);
                cb = NULL;
                cl->writing_state = MEI_WRITE_COMPLETE;
                if (waitqueue_active(&cl->tx_wait))
                        wake_up_interruptible(&cl->tx_wait);

        } else if (cb->fop_type == MEI_FOP_READ &&
                        MEI_READING == cl->reading_state) {
                cl->reading_state = MEI_READ_COMPLETE;
                if (waitqueue_active(&cl->rx_wait))
                        wake_up_interruptible(&cl->rx_wait);
                else
                        mei_cl_bus_rx_event(cl);

        }
}


/**
 * 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) {
                cl->state = MEI_FILE_DISCONNECTED;
                cl->mei_flow_ctrl_creds = 0;
                cl->timer_count = 0;
        }
}


/**
 * mei_cl_all_wakeup  - wake up all readers and writers they can be interrupted
 *
 * @dev  - mei device
 */
void mei_cl_all_wakeup(struct mei_device *dev)
{
        struct mei_cl *cl;
        list_for_each_entry(cl, &dev->file_list, link) {
                if (waitqueue_active(&cl->rx_wait)) {
                        cl_dbg(dev, cl, "Waking up reading client!\n");
                        wake_up_interruptible(&cl->rx_wait);
                }
                if (waitqueue_active(&cl->tx_wait)) {
                        cl_dbg(dev, cl, "Waking up writing client!\n");
                        wake_up_interruptible(&cl->tx_wait);
                }
        }
}

/**
 * mei_cl_all_write_clear - clear all pending writes

 * @dev - mei device
 */
void mei_cl_all_write_clear(struct mei_device *dev)
{
        mei_io_list_free(&dev->write_list, NULL);
        mei_io_list_free(&dev->write_waiting_list, NULL);
}