// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2003-2020, Intel Corporation. All rights reserved.
 * Intel Management Engine Interface (Intel MEI) Linux driver
 */

#include <linux/sched/signal.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/pm_runtime.h>
#include <linux/dma-mapping.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_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_enqueue - 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_cl_set_read_by_fp - set pending_read flag to vtag struct for given fp
 *
 * Locking: called under "dev->device_lock" lock
 *
 * @cl: mei client
 * @fp: pointer to file structure
 */
static void mei_cl_set_read_by_fp(const struct mei_cl *cl,
                                  const struct file *fp)
{
        struct mei_cl_vtag *cl_vtag;

        list_for_each_entry(cl_vtag, &cl->vtag_map, list) {
                if (cl_vtag->fp == fp) {
                        cl_vtag->pending_read = true;
                        return;
                }
        }
}

/**
 * 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(*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;
        cb->vtag = 0;

        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 (cl == cb->cl) {
                        list_del_init(&cb->list);
                        if (cb->fop_type == MEI_FOP_READ)
                                mei_io_cb_free(cb);
                }
        }
}

/**
 * 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
 * @fp: file pointer (matching cb file object), may be NULL
 */
static void mei_io_tx_list_free_cl(struct list_head *head,
                                   const struct mei_cl *cl,
                                   const struct file *fp)
{
        struct mei_cl_cb *cb, *next;

        list_for_each_entry_safe(cb, next, head, list) {
                if (cl == cb->cl && (!fp || fp == cb->fp))
                        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_free_pending - free pending cb
 *
 * @cl: host client
 */
static void mei_cl_free_pending(struct mei_cl *cl)
{
        struct mei_cl_cb *cb;

        cb = list_first_entry_or_null(&cl->rd_pending, struct mei_cl_cb, list);
        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(roundup(length, MEI_SLOT_SIZE), 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(struct mei_cl *cl, const struct file *fp)
{
        struct mei_cl_cb *cb;
        struct mei_cl_cb *ret_cb = NULL;

        spin_lock(&cl->rd_completed_lock);
        list_for_each_entry(cb, &cl->rd_completed, list)
                if (!fp || fp == cb->fp) {
                        ret_cb = cb;
                        break;
                }
        spin_unlock(&cl->rd_completed_lock);
        return ret_cb;
}

/**
 * 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, fp);
        mei_io_tx_list_free_cl(&cl->dev->write_waiting_list, cl, fp);
        /* free pending and control cb only in final flush */
        if (!fp) {
                mei_io_list_flush_cl(&cl->dev->ctrl_wr_list, cl);
                mei_io_list_flush_cl(&cl->dev->ctrl_rd_list, cl);
                mei_cl_free_pending(cl);
        }
        spin_lock(&cl->rd_completed_lock);
        mei_io_list_free_fp(&cl->rd_completed, fp);
        spin_unlock(&cl->rd_completed_lock);

        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(*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->vtag_map);
        spin_lock_init(&cl->rd_completed_lock);
        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(*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)
{
        mei_set_devstate(dev, 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, NULL);
        mei_io_tx_list_free_cl(&dev->write_waiting_list, cl, NULL);
        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_POWERING_DOWN ||
            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_vtag_alloc - allocate and fill the vtag structure
 *
 * @fp: pointer to file structure
 * @vtag: vm tag
 *
 * Return:
 * * Pointer to allocated struct - on success
 * * ERR_PTR(-ENOMEM) on memory allocation failure
 */
struct mei_cl_vtag *mei_cl_vtag_alloc(struct file *fp, u8 vtag)
{
        struct mei_cl_vtag *cl_vtag;

        cl_vtag = kzalloc(sizeof(*cl_vtag), GFP_KERNEL);
        if (!cl_vtag)
                return ERR_PTR(-ENOMEM);

        INIT_LIST_HEAD(&cl_vtag->list);
        cl_vtag->vtag = vtag;
        cl_vtag->fp = fp;

        return cl_vtag;
}

/**
 * mei_cl_fp_by_vtag - obtain the file pointer by vtag
 *
 * @cl: host client
 * @vtag: virtual tag
 *
 * Return:
 * * A file pointer - on success
 * * ERR_PTR(-ENOENT) if vtag is not found in the client vtag list
 */
const struct file *mei_cl_fp_by_vtag(const struct mei_cl *cl, u8 vtag)
{
        struct mei_cl_vtag *vtag_l;

        list_for_each_entry(vtag_l, &cl->vtag_map, list)
                /* The client on bus has one fixed fp */
                if ((cl->cldev && mei_cldev_enabled(cl->cldev)) ||
                    vtag_l->vtag == vtag)
                        return vtag_l->fp;

        return ERR_PTR(-ENOENT);
}

/**
 * mei_cl_reset_read_by_vtag - reset pending_read flag by given vtag
 *
 * @cl: host client
 * @vtag: vm tag
 */
static void mei_cl_reset_read_by_vtag(const struct mei_cl *cl, u8 vtag)
{
        struct mei_cl_vtag *vtag_l;

        list_for_each_entry(vtag_l, &cl->vtag_map, list) {
                if (vtag_l->vtag == vtag) {
                        vtag_l->pending_read = false;
                        break;
                }
        }
}

/**
 * mei_cl_read_vtag_add_fc - add flow control for next pending reader
 *                           in the vtag list
 *
 * @cl: host client
 */
static void mei_cl_read_vtag_add_fc(struct mei_cl *cl)
{
        struct mei_cl_vtag *cl_vtag;

        list_for_each_entry(cl_vtag, &cl->vtag_map, list) {
                if (cl_vtag->pending_read) {
                        if (mei_cl_enqueue_ctrl_wr_cb(cl,
                                                      mei_cl_mtu(cl),
                                                      MEI_FOP_READ,
                                                      cl_vtag->fp))
                                cl->rx_flow_ctrl_creds++;
                        break;
                }
        }
}

/**
 * mei_cl_vt_support_check - check if client support vtags
 *
 * @cl: host client
 *
 * Return:
 * * 0 - supported, or not connected at all
 * * -EOPNOTSUPP - vtags are not supported by client
 */
int mei_cl_vt_support_check(const struct mei_cl *cl)
{
        struct mei_device *dev = cl->dev;

        if (!dev->hbm_f_vt_supported)
                return -EOPNOTSUPP;

        if (!cl->me_cl)
                return 0;

        return cl->me_cl->props.vt_supported ? 0 : -EOPNOTSUPP;
}

/**
 * mei_cl_add_rd_completed - add read completed callback to list with lock
 *                           and vtag check
 *
 * @cl: host client
 * @cb: callback block
 *
 */
void mei_cl_add_rd_completed(struct mei_cl *cl, struct mei_cl_cb *cb)
{
        const struct file *fp;

        if (!mei_cl_vt_support_check(cl)) {
                fp = mei_cl_fp_by_vtag(cl, cb->vtag);
                if (IS_ERR(fp)) {
                        /* client already disconnected, discarding */
                        mei_io_cb_free(cb);
                        return;
                }
                cb->fp = fp;
                mei_cl_reset_read_by_vtag(cl, cb->vtag);
                mei_cl_read_vtag_add_fc(cl);
        }

        spin_lock(&cl->rd_completed_lock);
        list_add_tail(&cb->list, &cl->rd_completed);
        spin_unlock(&cl->rd_completed_lock);
}

/**
 * mei_cl_del_rd_completed - free read completed callback with lock
 *
 * @cl: host client
 * @cb: callback block
 *
 */
void mei_cl_del_rd_completed(struct mei_cl *cl, struct mei_cl_cb *cb)
{
        spin_lock(&cl->rd_completed_lock);
        mei_io_cb_free(cb);
        spin_unlock(&cl->rd_completed_lock);
}

/**
 *  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 ||
                           cl->status ||
                           !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) {
                mei_cl_set_read_by_fp(cl, fp);
                return -EBUSY;
        }

        cb = mei_cl_enqueue_ctrl_wr_cb(cl, length, MEI_FOP_READ, fp);
        if (!cb)
                return -ENOMEM;

        mei_cl_set_read_by_fp(cl, fp);

        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;
}

static inline u8 mei_ext_hdr_set_vtag(void *ext, u8 vtag)
{
        struct mei_ext_hdr_vtag *vtag_hdr = ext;

        vtag_hdr->hdr.type = MEI_EXT_HDR_VTAG;
        vtag_hdr->hdr.length = mei_data2slots(sizeof(*vtag_hdr));
        vtag_hdr->vtag = vtag;
        vtag_hdr->reserved = 0;
        return vtag_hdr->hdr.length;
}

/**
 * mei_msg_hdr_init - allocate and initialize mei message header
 *
 * @cb: message callback structure
 *
 * Return: a pointer to initialized header or ERR_PTR on failure
 */
static struct mei_msg_hdr *mei_msg_hdr_init(const struct mei_cl_cb *cb)
{
        size_t hdr_len;
        struct mei_ext_meta_hdr *meta;
        struct mei_msg_hdr *mei_hdr;
        bool is_ext, is_vtag;

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

        /* Extended header for vtag is attached only on the first fragment */
        is_vtag = (cb->vtag && cb->buf_idx == 0);
        is_ext = is_vtag;

        /* Compute extended header size */
        hdr_len = sizeof(*mei_hdr);

        if (!is_ext)
                goto setup_hdr;

        hdr_len += sizeof(*meta);
        if (is_vtag)
                hdr_len += sizeof(struct mei_ext_hdr_vtag);

setup_hdr:
        mei_hdr = kzalloc(hdr_len, GFP_KERNEL);
        if (!mei_hdr)
                return ERR_PTR(-ENOMEM);

        mei_hdr->host_addr = mei_cl_host_addr(cb->cl);
        mei_hdr->me_addr = mei_cl_me_id(cb->cl);
        mei_hdr->internal = cb->internal;
        mei_hdr->extended = is_ext;

        if (!is_ext)
                goto out;

        meta = (struct mei_ext_meta_hdr *)mei_hdr->extension;
        if (is_vtag) {
                meta->count++;
                meta->size += mei_ext_hdr_set_vtag(meta->hdrs, cb->vtag);
        }
out:
        mei_hdr->length = hdr_len - sizeof(*mei_hdr);
        return mei_hdr;
}

/**
 * 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 = NULL;
        size_t hdr_len;
        size_t hbuf_len, dr_len;
        size_t buf_len;
        size_t data_len;
        int hbuf_slots;
        u32 dr_slots;
        u32 dma_len;
        int rets;
        bool first_chunk;
        const void *data;

        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;
        }

        buf_len = buf->size - cb->buf_idx;
        data = buf->data + 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_MAX_LEN_MASK;
        dr_slots = mei_dma_ring_empty_slots(dev);
        dr_len = mei_slots2data(dr_slots);

        mei_hdr = mei_msg_hdr_init(cb);
        if (IS_ERR(mei_hdr)) {
                rets = PTR_ERR(mei_hdr);
                mei_hdr = NULL;
                goto err;
        }

        cl_dbg(dev, cl, "Extended Header %d vtag = %d\n",
               mei_hdr->extended, cb->vtag);

        hdr_len = sizeof(*mei_hdr) + mei_hdr->length;

        /**
         * Split the message only if we can write the whole host buffer
         * otherwise wait for next time the host buffer is empty.
         */
        if (hdr_len + buf_len <= hbuf_len) {
                data_len = buf_len;
                mei_hdr->msg_complete = 1;
        } else if (dr_slots && hbuf_len >= hdr_len + sizeof(dma_len)) {
                mei_hdr->dma_ring = 1;
                if (buf_len > dr_len)
                        buf_len = dr_len;
                else
                        mei_hdr->msg_complete = 1;

                data_len = sizeof(dma_len);
                dma_len = buf_len;
                data = &dma_len;
        } else if ((u32)hbuf_slots == mei_hbuf_depth(dev)) {
                buf_len = hbuf_len - hdr_len;
                data_len = buf_len;
        } else {
                kfree(mei_hdr);
                return 0;
        }
        mei_hdr->length += data_len;

        if (mei_hdr->dma_ring)
                mei_dma_ring_write(dev, buf->data + cb->buf_idx, buf_len);
        rets = mei_write_message(dev, mei_hdr, hdr_len, data, data_len);

        if (rets)
                goto err;

        cl->status = 0;
        cl->writing_state = MEI_WRITING;
        cb->buf_idx += buf_len;

        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);

        kfree(mei_hdr);
        return 0;

err:
        kfree(mei_hdr);
        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 = NULL;
        size_t hdr_len;
        size_t hbuf_len, dr_len;
        size_t buf_len;
        size_t data_len;
        int hbuf_slots;
        u32 dr_slots;
        u32 dma_len;
        ssize_t rets;
        bool blocking;
        const void *data;

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

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

        dev = cl->dev;

        buf = &cb->buf;
        buf_len = buf->size;

        cl_dbg(dev, cl, "buf_len=%zd\n", buf_len);

        blocking = cb->blocking;
        data = buf->data;

        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_hdr = mei_msg_hdr_init(cb);
        if (IS_ERR(mei_hdr)) {
                rets = -PTR_ERR(mei_hdr);
                mei_hdr = NULL;
                goto err;
        }

        cl_dbg(dev, cl, "Extended Header %d vtag = %d\n",
               mei_hdr->extended, cb->vtag);

        hdr_len = sizeof(*mei_hdr) + mei_hdr->length;

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

        if (!mei_hbuf_acquire(dev)) {
                cl_dbg(dev, cl, "Cannot acquire the host buffer: not sending.\n");
                rets = buf_len;
                goto out;
        }

        hbuf_slots = mei_hbuf_empty_slots(dev);

        if (hbuf_slots < 0) {
                rets = -EOVERFLOW;
                goto out;
        }

        hbuf_len = mei_slots2data(hbuf_slots) & MEI_MSG_MAX_LEN_MASK;
        dr_slots = mei_dma_ring_empty_slots(dev);
        dr_len =  mei_slots2data(dr_slots);

        if (hdr_len + buf_len <= hbuf_len) {
                data_len = buf_len;
                mei_hdr->msg_complete = 1;
        } else if (dr_slots && hbuf_len >= hdr_len + sizeof(dma_len)) {
                mei_hdr->dma_ring = 1;
                if (buf_len > dr_len)
                        buf_len = dr_len;
                else
                        mei_hdr->msg_complete = 1;

                data_len = sizeof(dma_len);
                dma_len = buf_len;
                data = &dma_len;
        } else {
                buf_len = hbuf_len - hdr_len;
                data_len = buf_len;
        }

        mei_hdr->length += data_len;

        if (mei_hdr->dma_ring)
                mei_dma_ring_write(dev, buf->data, buf_len);
        rets = mei_write_message(dev, mei_hdr, hdr_len, data, data_len);

        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 = buf_len;
        /* restore return value */
        buf_len = buf->size;

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 = buf_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);

        kfree(mei_hdr);

        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:
                mei_cl_add_rd_completed(cl, cb);
                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:
        case MEI_FOP_DMA_MAP:
        case MEI_FOP_DMA_UNMAP:
                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);
}

static struct mei_cl *mei_cl_dma_map_find(struct mei_device *dev, u8 buffer_id)
{
        struct mei_cl *cl;

        list_for_each_entry(cl, &dev->file_list, link)
                if (cl->dma.buffer_id == buffer_id)
                        return cl;
        return NULL;
}

/**
 * mei_cl_irq_dma_map - send client dma map 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_dma_map(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_dma_map_request));
        slots = mei_hbuf_empty_slots(dev);
        if (slots < 0)
                return -EOVERFLOW;

        if ((u32)slots < msg_slots)
                return -EMSGSIZE;

        ret = mei_hbm_cl_dma_map_req(dev, cl);
        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_irq_dma_unmap - send client dma unmap 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_dma_unmap(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_dma_unmap_request));
        slots = mei_hbuf_empty_slots(dev);
        if (slots < 0)
                return -EOVERFLOW;

        if ((u32)slots < msg_slots)
                return -EMSGSIZE;

        ret = mei_hbm_cl_dma_unmap_req(dev, cl);
        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;
}

static int mei_cl_dma_alloc(struct mei_cl *cl, u8 buf_id, size_t size)
{
        cl->dma.vaddr = dmam_alloc_coherent(cl->dev->dev, size,
                                            &cl->dma.daddr, GFP_KERNEL);
        if (!cl->dma.vaddr)
                return -ENOMEM;

        cl->dma.buffer_id = buf_id;
        cl->dma.size = size;

        return 0;
}

static void mei_cl_dma_free(struct mei_cl *cl)
{
        cl->dma.buffer_id = 0;
        dmam_free_coherent(cl->dev->dev,
                           cl->dma.size, cl->dma.vaddr, cl->dma.daddr);
        cl->dma.size = 0;
        cl->dma.vaddr = NULL;
        cl->dma.daddr = 0;
}

/**
 * mei_cl_dma_alloc_and_map - send client dma map request
 *
 * @cl: host client
 * @fp: pointer to file structure
 * @buffer_id: id of the mapped buffer
 * @size: size of the buffer
 *
 * Locking: called under "dev->device_lock" lock
 *
 * Return:
 * * -ENODEV
 * * -EINVAL
 * * -EOPNOTSUPP
 * * -EPROTO
 * * -ENOMEM;
 */
int mei_cl_dma_alloc_and_map(struct mei_cl *cl, const struct file *fp,
                             u8 buffer_id, size_t size)
{
        struct mei_device *dev;
        struct mei_cl_cb *cb;
        int rets;

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

        dev = cl->dev;

        if (!dev->hbm_f_cd_supported) {
                cl_dbg(dev, cl, "client dma is not supported\n");
                return -EOPNOTSUPP;
        }

        if (buffer_id == 0)
                return -EINVAL;

        if (mei_cl_is_connected(cl))
                return -EPROTO;

        if (cl->dma_mapped)
                return -EPROTO;

        if (mei_cl_dma_map_find(dev, buffer_id)) {
                cl_dbg(dev, cl, "client dma with id %d is already allocated\n",
                       cl->dma.buffer_id);
                return -EPROTO;
        }

        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_dma_alloc(cl, buffer_id, size);
        if (rets) {
                pm_runtime_put_noidle(dev->dev);
                return rets;
        }

        cb = mei_cl_enqueue_ctrl_wr_cb(cl, 0, MEI_FOP_DMA_MAP, fp);
        if (!cb) {
                rets = -ENOMEM;
                goto out;
        }

        if (mei_hbuf_acquire(dev)) {
                if (mei_hbm_cl_dma_map_req(dev, cl)) {
                        rets = -ENODEV;
                        goto out;
                }
                list_move_tail(&cb->list, &dev->ctrl_rd_list);
        }

        mutex_unlock(&dev->device_lock);
        wait_event_timeout(cl->wait,
                           cl->dma_mapped || cl->status,
                           mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT));
        mutex_lock(&dev->device_lock);

        if (!cl->dma_mapped && !cl->status)
                cl->status = -EFAULT;

        rets = cl->status;

out:
        if (rets)
                mei_cl_dma_free(cl);

        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_dma_unmap - send client dma unmap request
 *
 * @cl: host client
 * @fp: pointer to file structure
 *
 * Locking: called under "dev->device_lock" lock
 *
 * Return: 0 on such and error otherwise.
 */
int mei_cl_dma_unmap(struct mei_cl *cl, 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 (!dev->hbm_f_cd_supported) {
                cl_dbg(dev, cl, "client dma is not supported\n");
                return -EOPNOTSUPP;
        }

        /* do not allow unmap for connected client */
        if (mei_cl_is_connected(cl))
                return -EPROTO;

        if (!cl->dma_mapped)
                return -EPROTO;

        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;
        }

        cb = mei_cl_enqueue_ctrl_wr_cb(cl, 0, MEI_FOP_DMA_UNMAP, fp);
        if (!cb) {
                rets = -ENOMEM;
                goto out;
        }

        if (mei_hbuf_acquire(dev)) {
                if (mei_hbm_cl_dma_unmap_req(dev, cl)) {
                        rets = -ENODEV;
                        goto out;
                }
                list_move_tail(&cb->list, &dev->ctrl_rd_list);
        }

        mutex_unlock(&dev->device_lock);
        wait_event_timeout(cl->wait,
                           !cl->dma_mapped || cl->status,
                           mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT));
        mutex_lock(&dev->device_lock);

        if (cl->dma_mapped && !cl->status)
                cl->status = -EFAULT;

        rets = cl->status;

        if (!rets)
                mei_cl_dma_free(cl);
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;
}