text: /*
   *
   * 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/kthread.h>
  #include <linux/interrupt.h>
  #include <linux/fs.h>
  #include <linux/jiffies.h>
  
  #include "mei_dev.h"
  #include <linux/mei.h>
  #include "hw.h"
  #include "interface.h"
  
  
  /**
   * mei_interrupt_quick_handler - The ISR of the MEI device
   *
   * @irq: The irq number
   * @dev_id: pointer to the device structure
   *
   * returns irqreturn_t
   */
  irqreturn_t mei_interrupt_quick_handler(int irq, void *dev_id)
  {
  	struct mei_device *dev = (struct mei_device *) dev_id;
  	u32 csr_reg = mei_hcsr_read(dev);
  
  	if ((csr_reg & H_IS) != H_IS)
  		return IRQ_NONE;
  
  	/* clear H_IS bit in H_CSR */
  	mei_reg_write(dev, H_CSR, csr_reg);
  
  	return IRQ_WAKE_THREAD;
  }
  
  /**
   * _mei_cmpl - processes completed operation.
   *
   * @cl: private data of the file object.
   * @cb_pos: callback block.
   */
  static void _mei_cmpl(struct mei_cl *cl, struct mei_cl_cb *cb_pos)
  {
  	if (cb_pos->major_file_operations == MEI_WRITE) {
  		mei_free_cb_private(cb_pos);
  		cb_pos = NULL;
  		cl->writing_state = MEI_WRITE_COMPLETE;
  		if (waitqueue_active(&cl->tx_wait))
  			wake_up_interruptible(&cl->tx_wait);
  
  	} else if (cb_pos->major_file_operations == MEI_READ &&
  			MEI_READING == cl->reading_state) {
  		cl->reading_state = MEI_READ_COMPLETE;
  		if (waitqueue_active(&cl->rx_wait))
  			wake_up_interruptible(&cl->rx_wait);
  
  	}
  }
  
  /**
   * _mei_cmpl_iamthif - processes completed iamthif operation.
   *
   * @dev: the device structure.
   * @cb_pos: callback block.
   */
  static void _mei_cmpl_iamthif(struct mei_device *dev, struct mei_cl_cb *cb_pos)
  {
  	if (dev->iamthif_canceled != 1) {
  		dev->iamthif_state = MEI_IAMTHIF_READ_COMPLETE;
  		dev->iamthif_stall_timer = 0;
  		memcpy(cb_pos->response_buffer.data,
  				dev->iamthif_msg_buf,
  				dev->iamthif_msg_buf_index);
  		list_add_tail(&cb_pos->cb_list,
  				&dev->amthi_read_complete_list.mei_cb.cb_list);
  		dev_dbg(&dev->pdev->dev, "amthi read completed.\n");
  		dev->iamthif_timer = jiffies;
  		dev_dbg(&dev->pdev->dev, "dev->iamthif_timer = %ld\n",
  				dev->iamthif_timer);
  	} else {
  		mei_run_next_iamthif_cmd(dev);
  	}
  
  	dev_dbg(&dev->pdev->dev, "completing amthi call back.\n");
  	wake_up_interruptible(&dev->iamthif_cl.wait);
  }
  
  
  /**
   * mei_irq_thread_read_amthi_message - bottom half read routine after ISR to
   * handle the read amthi message data processing.
   *
   * @complete_list: An instance of our list structure
   * @dev: the device structure
   * @mei_hdr: header of amthi message
   *
   * returns 0 on success, <0 on failure.
   */
  static int mei_irq_thread_read_amthi_message(struct mei_io_list *complete_list,
  		struct mei_device *dev,
  		struct mei_msg_hdr *mei_hdr)
  {
  	struct mei_cl *cl;
  	struct mei_cl_cb *cb;
  	unsigned char *buffer;
  
  	BUG_ON(mei_hdr->me_addr != dev->iamthif_cl.me_client_id);
  	BUG_ON(dev->iamthif_state != MEI_IAMTHIF_READING);
  
  	buffer = dev->iamthif_msg_buf + dev->iamthif_msg_buf_index;
  	BUG_ON(dev->iamthif_mtu < dev->iamthif_msg_buf_index + mei_hdr->length);
  
  	mei_read_slots(dev, buffer, mei_hdr->length);
  
  	dev->iamthif_msg_buf_index += mei_hdr->length;
  
  	if (!mei_hdr->msg_complete)
  		return 0;
  
  	dev_dbg(&dev->pdev->dev,
  			"amthi_message_buffer_index =%d\n",
  			mei_hdr->length);
  
  	dev_dbg(&dev->pdev->dev, "completed amthi read.\n ");
  	if (!dev->iamthif_current_cb)
  		return -ENODEV;
  
  	cb = dev->iamthif_current_cb;
  	dev->iamthif_current_cb = NULL;
  
  	cl = (struct mei_cl *)cb->file_private;
  	if (!cl)
  		return -ENODEV;
  
  	dev->iamthif_stall_timer = 0;
  	cb->information =	dev->iamthif_msg_buf_index;
  	cb->read_time = jiffies;
  	if (dev->iamthif_ioctl && cl == &dev->iamthif_cl) {
  		/* found the iamthif cb */
  		dev_dbg(&dev->pdev->dev, "complete the amthi read cb.\n ");
  		dev_dbg(&dev->pdev->dev, "add the amthi read cb to complete.\n ");
  		list_add_tail(&cb->cb_list,
  						&complete_list->mei_cb.cb_list);
  	}
  	return 0;
  }
  
  /**
   * _mei_irq_thread_state_ok - checks if mei header matches file private data
   *
   * @cl: private data of the file object
   * @mei_hdr: header of mei client message
   *
   * returns !=0 if matches, 0 if no match.
   */
  static int _mei_irq_thread_state_ok(struct mei_cl *cl,
  				struct mei_msg_hdr *mei_hdr)
  {
  	return (cl->host_client_id == mei_hdr->host_addr &&
  		cl->me_client_id == mei_hdr->me_addr &&
  		cl->state == MEI_FILE_CONNECTED &&
  		MEI_READ_COMPLETE != cl->reading_state);
  }
  
  /**
   * mei_irq_thread_read_client_message - bottom half read routine after ISR to
   * handle the read mei client message data processing.
   *
   * @complete_list: An instance of our list structure
   * @dev: the device structure
   * @mei_hdr: header of mei client message
   *
   * returns 0 on success, <0 on failure.
   */
  static int mei_irq_thread_read_client_message(struct mei_io_list *complete_list,
  		struct mei_device *dev,
  		struct mei_msg_hdr *mei_hdr)
  {
  	struct mei_cl *cl;
  	struct mei_cl_cb *cb_pos = NULL, *cb_next = NULL;
  	unsigned char *buffer = NULL;
  
  	dev_dbg(&dev->pdev->dev, "start client msg\n");
  	if (list_empty(&dev->read_list.mei_cb.cb_list))
  		goto quit;
  
  	list_for_each_entry_safe(cb_pos, cb_next,
  			&dev->read_list.mei_cb.cb_list, cb_list) {
  		cl = (struct mei_cl *)cb_pos->file_private;
  		if (cl && _mei_irq_thread_state_ok(cl, mei_hdr)) {
  			cl->reading_state = MEI_READING;
  			buffer = cb_pos->response_buffer.data + cb_pos->information;
  
  			if (cb_pos->response_buffer.size <
  					mei_hdr->length + cb_pos->information) {
  				dev_dbg(&dev->pdev->dev, "message overflow.\n");
  				list_del(&cb_pos->cb_list);
  				return -ENOMEM;
  			}
  			if (buffer)
  				mei_read_slots(dev, buffer, mei_hdr->length);
  
  			cb_pos->information += mei_hdr->length;
  			if (mei_hdr->msg_complete) {
  				cl->status = 0;
  				list_del(&cb_pos->cb_list);
  				dev_dbg(&dev->pdev->dev,
  					"completed read H cl = %d, ME cl = %d, length = %lu\n",
  					cl->host_client_id,
  					cl->me_client_id,
  					cb_pos->information);
  				list_add_tail(&cb_pos->cb_list,
  					&complete_list->mei_cb.cb_list);
  			}
  
  			break;
  		}
  
  	}
  
  quit:
  	dev_dbg(&dev->pdev->dev, "message read\n");
  	if (!buffer) {
  		mei_read_slots(dev, dev->rd_msg_buf, mei_hdr->length);
  		dev_dbg(&dev->pdev->dev, "discarding message, header =%08x.\n",
  				*(u32 *) dev->rd_msg_buf);
  	}
  
  	return 0;
  }
  
  /**
   * _mei_irq_thread_iamthif_read - prepares to read iamthif data.
   *
   * @dev: the device structure.
   * @slots: free slots.
   *
   * returns 0, OK; otherwise, error.
   */
  static int _mei_irq_thread_iamthif_read(struct mei_device *dev, s32 *slots)
  {
  
  	if (((*slots) * sizeof(u32)) < (sizeof(struct mei_msg_hdr)
  			+ sizeof(struct hbm_flow_control))) {
  		return -EMSGSIZE;
  	}
  	*slots -= mei_data2slots(sizeof(struct hbm_flow_control));
  	if (mei_send_flow_control(dev, &dev->iamthif_cl)) {
  		dev_dbg(&dev->pdev->dev, "iamthif flow control failed\n");
  		return -EIO;
  	}
  
  	dev_dbg(&dev->pdev->dev, "iamthif flow control success\n");
  	dev->iamthif_state = MEI_IAMTHIF_READING;
  	dev->iamthif_flow_control_pending = false;
  	dev->iamthif_msg_buf_index = 0;
  	dev->iamthif_msg_buf_size = 0;
  	dev->iamthif_stall_timer = IAMTHIF_STALL_TIMER;
  	dev->mei_host_buffer_is_empty = mei_hbuf_is_empty(dev);
  	return 0;
  }
  
  /**
   * _mei_irq_thread_close - processes close related operation.
   *
   * @dev: the device structure.
   * @slots: free slots.
   * @cb_pos: callback block.
   * @cl: private data of the file object.
   * @cmpl_list: complete list.
   *
   * returns 0, OK; otherwise, error.
   */
  static int _mei_irq_thread_close(struct mei_device *dev, s32 *slots,
  				struct mei_cl_cb *cb_pos,
  				struct mei_cl *cl,
  				struct mei_io_list *cmpl_list)
  {
  	if ((*slots * sizeof(u32)) < (sizeof(struct mei_msg_hdr) +
  			sizeof(struct hbm_client_disconnect_request)))
  		return -EBADMSG;
  
  	*slots -= mei_data2slots(sizeof(struct hbm_client_disconnect_request));
  
  	if (mei_disconnect(dev, cl)) {
  		cl->status = 0;
  		cb_pos->information = 0;
  		list_move_tail(&cb_pos->cb_list,
  				&cmpl_list->mei_cb.cb_list);
  		return -EMSGSIZE;
  	} else {
  		cl->state = MEI_FILE_DISCONNECTING;
  		cl->status = 0;
  		cb_pos->information = 0;
  		list_move_tail(&cb_pos->cb_list,
  				&dev->ctrl_rd_list.mei_cb.cb_list);
  		cl->timer_count = MEI_CONNECT_TIMEOUT;
  	}
  
  	return 0;
  }
  
  /**
   * is_treat_specially_client - checks if the message belongs
   * to the file private data.
   *
   * @cl: private data of the file object
   * @rs: connect response bus message
   *
   */
  static bool is_treat_specially_client(struct mei_cl *cl,
  		struct hbm_client_connect_response *rs)
  {
  
  	if (cl->host_client_id == rs->host_addr &&
  	    cl->me_client_id == rs->me_addr) {
  		if (!rs->status) {
  			cl->state = MEI_FILE_CONNECTED;
  			cl->status = 0;
  
  		} else {
  			cl->state = MEI_FILE_DISCONNECTED;
  			cl->status = -ENODEV;
  		}
  		cl->timer_count = 0;
  
  		return true;
  	}
  	return false;
  }
  
  /**
   * mei_client_connect_response - connects to response irq routine
   *
   * @dev: the device structure
   * @rs: connect response bus message
   */
  static void mei_client_connect_response(struct mei_device *dev,
  		struct hbm_client_connect_response *rs)
  {
  
  	struct mei_cl *cl;
  	struct mei_cl_cb *cb_pos = NULL, *cb_next = NULL;
  
  	dev_dbg(&dev->pdev->dev,
  			"connect_response:\n"
  			"ME Client = %d\n"
  			"Host Client = %d\n"
  			"Status = %d\n",
  			rs->me_addr,
  			rs->host_addr,
  			rs->status);
  
  	/* if WD or iamthif client treat specially */
  
  	if (is_treat_specially_client(&(dev->wd_cl), rs)) {
  		dev_dbg(&dev->pdev->dev, "successfully connected to WD client.\n");
  		mei_watchdog_register(dev);
  
  		/* next step in the state maching */
  		mei_host_init_iamthif(dev);
  		return;
  	}
  
  	if (is_treat_specially_client(&(dev->iamthif_cl), rs)) {
  		dev->iamthif_state = MEI_IAMTHIF_IDLE;
  		return;
  	}
  	list_for_each_entry_safe(cb_pos, cb_next,
  				&dev->ctrl_rd_list.mei_cb.cb_list, cb_list) {
  
  		cl = (struct mei_cl *)cb_pos->file_private;
  		if (!cl) {
  			list_del(&cb_pos->cb_list);
  			return;
  		}
  		if (MEI_IOCTL == cb_pos->major_file_operations) {
  			if (is_treat_specially_client(cl, rs)) {
  				list_del(&cb_pos->cb_list);
  				cl->status = 0;
  				cl->timer_count = 0;
  				break;
  			}
  		}
  	}
  }
  
  /**
   * mei_client_disconnect_response - disconnects from response irq routine
   *
   * @dev: the device structure
   * @rs: disconnect response bus message
   */
  static void mei_client_disconnect_response(struct mei_device *dev,
  					struct hbm_client_connect_response *rs)
  {
  	struct mei_cl *cl;
  	struct mei_cl_cb *cb_pos = NULL, *cb_next = NULL;
  
  	dev_dbg(&dev->pdev->dev,
  			"disconnect_response:\n"
  			"ME Client = %d\n"
  			"Host Client = %d\n"
  			"Status = %d\n",
  			rs->me_addr,
  			rs->host_addr,
  			rs->status);
  
  	list_for_each_entry_safe(cb_pos, cb_next,
  			&dev->ctrl_rd_list.mei_cb.cb_list, cb_list) {
  		cl = (struct mei_cl *)cb_pos->file_private;
  
  		if (!cl) {
  			list_del(&cb_pos->cb_list);
  			return;
  		}
  
  		dev_dbg(&dev->pdev->dev, "list_for_each_entry_safe in ctrl_rd_list.\n");
  		if (cl->host_client_id == rs->host_addr &&
  		    cl->me_client_id == rs->me_addr) {
  
  			list_del(&cb_pos->cb_list);
  			if (!rs->status)
  				cl->state = MEI_FILE_DISCONNECTED;
  
  			cl->status = 0;
  			cl->timer_count = 0;
  			break;
  		}
  	}
  }
  
  /**
   * same_flow_addr - tells if they have the same address.
   *
   * @file: private data of the file object.
   * @flow: flow control.
   *
   * returns  !=0, same; 0,not.
   */
  static int same_flow_addr(struct mei_cl *cl, struct hbm_flow_control *flow)
  {
  	return (cl->host_client_id == flow->host_addr &&
  		cl->me_client_id == flow->me_addr);
  }
  
  /**
   * add_single_flow_creds - adds single buffer credentials.
   *
   * @file: private data ot the file object.
   * @flow: flow control.
   */
  static void add_single_flow_creds(struct mei_device *dev,
  				  struct hbm_flow_control *flow)
  {
  	struct mei_me_client *client;
  	int i;
  
  	for (i = 0; i < dev->me_clients_num; i++) {
  		client = &dev->me_clients[i];
  		if (client && flow->me_addr == client->client_id) {
  			if (client->props.single_recv_buf) {
  				client->mei_flow_ctrl_creds++;
  				dev_dbg(&dev->pdev->dev, "recv flow ctrl msg ME %d (single).\n",
  				    flow->me_addr);
  				dev_dbg(&dev->pdev->dev, "flow control credentials =%d.\n",
  				    client->mei_flow_ctrl_creds);
  			} else {
  				BUG();	/* error in flow control */
  			}
  		}
  	}
  }
  
  /**
   * mei_client_flow_control_response - flow control response irq routine
   *
   * @dev: the device structure
   * @flow_control: flow control response bus message
   */
  static void mei_client_flow_control_response(struct mei_device *dev,
  		struct hbm_flow_control *flow_control)
  {
  	struct mei_cl *cl_pos = NULL;
  	struct mei_cl *cl_next = NULL;
  
  	if (!flow_control->host_addr) {
  		/* single receive buffer */
  		add_single_flow_creds(dev, flow_control);
  	} else {
  		/* normal connection */
  		list_for_each_entry_safe(cl_pos, cl_next,
  				&dev->file_list, link) {
  			dev_dbg(&dev->pdev->dev, "list_for_each_entry_safe in file_list\n");
  
  			dev_dbg(&dev->pdev->dev, "cl of host client %d ME client %d.\n",
  			    cl_pos->host_client_id,
  			    cl_pos->me_client_id);
  			dev_dbg(&dev->pdev->dev, "flow ctrl msg for host %d ME %d.\n",
  			    flow_control->host_addr,
  			    flow_control->me_addr);
  			if (same_flow_addr(cl_pos, flow_control)) {
  				dev_dbg(&dev->pdev->dev, "recv ctrl msg for host  %d ME %d.\n",
  				    flow_control->host_addr,
  				    flow_control->me_addr);
  				cl_pos->mei_flow_ctrl_creds++;
  				dev_dbg(&dev->pdev->dev, "flow control credentials = %d.\n",
  				    cl_pos->mei_flow_ctrl_creds);
  				break;
  			}
  		}
  	}
  }
  
  /**
   * same_disconn_addr - tells if they have the same address
   *
   * @file: private data of the file object.
   * @disconn: disconnection request.
   *
   * returns !=0, same; 0,not.
   */
  static int same_disconn_addr(struct mei_cl *cl,
  			     struct hbm_client_disconnect_request *disconn)
  {
  	return (cl->host_client_id == disconn->host_addr &&
  		cl->me_client_id == disconn->me_addr);
  }
  
  /**
   * mei_client_disconnect_request - disconnects from request irq routine
   *
   * @dev: the device structure.
   * @disconnect_req: disconnect request bus message.
   */
  static void mei_client_disconnect_request(struct mei_device *dev,
  		struct hbm_client_disconnect_request *disconnect_req)
  {
  	struct mei_msg_hdr *mei_hdr;
  	struct hbm_client_connect_response *disconnect_res;
  	struct mei_cl *cl_pos = NULL;
  	struct mei_cl *cl_next = NULL;
  
  	list_for_each_entry_safe(cl_pos, cl_next, &dev->file_list, link) {
  		if (same_disconn_addr(cl_pos, disconnect_req)) {
  			dev_dbg(&dev->pdev->dev, "disconnect request host client %d ME client %d.\n",
  					disconnect_req->host_addr,
  					disconnect_req->me_addr);
  			cl_pos->state = MEI_FILE_DISCONNECTED;
  			cl_pos->timer_count = 0;
  			if (cl_pos == &dev->wd_cl)
  				dev->wd_pending = false;
  			else if (cl_pos == &dev->iamthif_cl)
  				dev->iamthif_timer = 0;
  
  			/* prepare disconnect response */
  			mei_hdr =
  				(struct mei_msg_hdr *) &dev->ext_msg_buf[0];
  			mei_hdr->host_addr = 0;
  			mei_hdr->me_addr = 0;
  			mei_hdr->length =
  				sizeof(struct hbm_client_connect_response);
  			mei_hdr->msg_complete = 1;
  			mei_hdr->reserved = 0;
  
  			disconnect_res =
  				(struct hbm_client_connect_response *)
  				&dev->ext_msg_buf[1];
  			disconnect_res->host_addr = cl_pos->host_client_id;
  			disconnect_res->me_addr = cl_pos->me_client_id;
  			disconnect_res->hbm_cmd = CLIENT_DISCONNECT_RES_CMD;
  			disconnect_res->status = 0;
  			dev->extra_write_index = 2;
  			break;
  		}
  	}
  }
  
  
  /**
   * mei_irq_thread_read_bus_message - bottom half read routine after ISR to
   * handle the read bus message cmd processing.
   *
   * @dev: the device structure
   * @mei_hdr: header of bus message
   */
  static void mei_irq_thread_read_bus_message(struct mei_device *dev,
  		struct mei_msg_hdr *mei_hdr)
  {
  	struct mei_bus_message *mei_msg;
  	struct hbm_host_version_response *version_res;
  	struct hbm_client_connect_response *connect_res;
  	struct hbm_client_connect_response *disconnect_res;
  	struct hbm_flow_control *flow_control;
  	struct hbm_props_response *props_res;
  	struct hbm_host_enum_response *enum_res;
  	struct hbm_client_disconnect_request *disconnect_req;
  	struct hbm_host_stop_request *host_stop_req;
  	int res;
  
  
  	/* read the message to our buffer */
  	BUG_ON(mei_hdr->length >= sizeof(dev->rd_msg_buf));
  	mei_read_slots(dev, dev->rd_msg_buf, mei_hdr->length);
  	mei_msg = (struct mei_bus_message *)dev->rd_msg_buf;
  
  	switch (mei_msg->hbm_cmd) {
  	case HOST_START_RES_CMD:
  		version_res = (struct hbm_host_version_response *) mei_msg;
  		if (version_res->host_version_supported) {
  			dev->version.major_version = HBM_MAJOR_VERSION;
  			dev->version.minor_version = HBM_MINOR_VERSION;
  			if (dev->dev_state == MEI_DEV_INIT_CLIENTS &&
  			    dev->init_clients_state == MEI_START_MESSAGE) {
  				dev->init_clients_timer = 0;
  				mei_host_enum_clients_message(dev);
  			} else {
  				dev->recvd_msg = false;
  				dev_dbg(&dev->pdev->dev, "IMEI reset due to received host start response bus message.\n");
  				mei_reset(dev, 1);
  				return;
  			}
  		} else {
  			dev->version = version_res->me_max_version;
  			/* send stop message */
  			mei_hdr = (struct mei_msg_hdr *)&dev->wr_msg_buf[0];
  			mei_hdr->host_addr = 0;
  			mei_hdr->me_addr = 0;
  			mei_hdr->length = sizeof(struct hbm_host_stop_request);
  			mei_hdr->msg_complete = 1;
  			mei_hdr->reserved = 0;
  
  			host_stop_req = (struct hbm_host_stop_request *)
  							&dev->wr_msg_buf[1];
  
  			memset(host_stop_req,
  					0,
  					sizeof(struct hbm_host_stop_request));
  			host_stop_req->hbm_cmd = HOST_STOP_REQ_CMD;
  			host_stop_req->reason = DRIVER_STOP_REQUEST;
  			mei_write_message(dev, mei_hdr,
  					   (unsigned char *) (host_stop_req),
  					   mei_hdr->length);
  			dev_dbg(&dev->pdev->dev, "version mismatch.\n");
  			return;
  		}
  
  		dev->recvd_msg = true;
  		dev_dbg(&dev->pdev->dev, "host start response message received.\n");
  		break;
  
  	case CLIENT_CONNECT_RES_CMD:
  		connect_res =
  			(struct hbm_client_connect_response *) mei_msg;
  		mei_client_connect_response(dev, connect_res);
  		dev_dbg(&dev->pdev->dev, "client connect response message received.\n");
  		wake_up(&dev->wait_recvd_msg);
  		break;
  
  	case CLIENT_DISCONNECT_RES_CMD:
  		disconnect_res =
  			(struct hbm_client_connect_response *) mei_msg;
  		mei_client_disconnect_response(dev, disconnect_res);
  		dev_dbg(&dev->pdev->dev, "client disconnect response message received.\n");
  		wake_up(&dev->wait_recvd_msg);
  		break;
  
  	case MEI_FLOW_CONTROL_CMD:
  		flow_control = (struct hbm_flow_control *) mei_msg;
  		mei_client_flow_control_response(dev, flow_control);
  		dev_dbg(&dev->pdev->dev, "client flow control response message received.\n");
  		break;
  
  	case HOST_CLIENT_PROPERTIES_RES_CMD:
  		props_res = (struct hbm_props_response *)mei_msg;
  		if (props_res->status || !dev->me_clients) {
  			dev_dbg(&dev->pdev->dev, "reset due to received host client properties response bus message wrong status.\n");
  			mei_reset(dev, 1);
  			return;
  		}
  		if (dev->me_clients[dev->me_client_presentation_num]
  					.client_id == props_res->address) {
  
  			dev->me_clients[dev->me_client_presentation_num].props
  						= props_res->client_properties;
  
  			if (dev->dev_state == MEI_DEV_INIT_CLIENTS &&
  			    dev->init_clients_state ==
  					MEI_CLIENT_PROPERTIES_MESSAGE) {
  				dev->me_client_index++;
  				dev->me_client_presentation_num++;
  
  				/** Send Client Properties request **/
  				res = mei_host_client_properties(dev);
  				if (res < 0) {
  					dev_dbg(&dev->pdev->dev, "mei_host_client_properties() failed");
  					return;
  				} else if (!res) {
  					/*
  					 * No more clients to send to.
  					 * Clear Map for indicating now ME clients
  					 * with associated host client
  					 */
  					bitmap_zero(dev->host_clients_map, MEI_CLIENTS_MAX);
  					dev->open_handle_count = 0;
  
  					/*
  					 * Reserving the first three client IDs
  					 * Client Id 0 - Reserved for MEI Bus Message communications
  					 * Client Id 1 - Reserved for Watchdog
  					 * Client ID 2 - Reserved for AMTHI
  					 */
  					bitmap_set(dev->host_clients_map, 0, 3);
  					dev->dev_state = MEI_DEV_ENABLED;
  
  					/* if wd initialization fails, initialization the AMTHI client,
  					 * otherwise the AMTHI client will be initialized after the WD client connect response
  					 * will be received
  					 */
  					if (mei_wd_host_init(dev))
  						mei_host_init_iamthif(dev);
  				}
  
  			} else {
  				dev_dbg(&dev->pdev->dev, "reset due to received host client properties response bus message");
  				mei_reset(dev, 1);
  				return;
  			}
  		} else {
  			dev_dbg(&dev->pdev->dev, "reset due to received host client properties response bus message for wrong client ID\n");
  			mei_reset(dev, 1);
  			return;
  		}
  		break;
  
  	case HOST_ENUM_RES_CMD:
  		enum_res = (struct hbm_host_enum_response *) mei_msg;
  		memcpy(dev->me_clients_map, enum_res->valid_addresses, 32);
  		if (dev->dev_state == MEI_DEV_INIT_CLIENTS &&
  		    dev->init_clients_state == MEI_ENUM_CLIENTS_MESSAGE) {
  				dev->init_clients_timer = 0;
  				dev->me_client_presentation_num = 0;
  				dev->me_client_index = 0;
  				mei_allocate_me_clients_storage(dev);
  				dev->init_clients_state =
  					MEI_CLIENT_PROPERTIES_MESSAGE;
  				mei_host_client_properties(dev);
  		} else {
  			dev_dbg(&dev->pdev->dev, "reset due to received host enumeration clients response bus message.\n");
  			mei_reset(dev, 1);
  			return;
  		}
  		break;
  
  	case HOST_STOP_RES_CMD:
  		dev->dev_state = MEI_DEV_DISABLED;
  		dev_dbg(&dev->pdev->dev, "resetting because of FW stop response.\n");
  		mei_reset(dev, 1);
  		break;
  
  	case CLIENT_DISCONNECT_REQ_CMD:
  		/* search for client */
  		disconnect_req =
  			(struct hbm_client_disconnect_request *) mei_msg;
  		mei_client_disconnect_request(dev, disconnect_req);
  		break;
  
  	case ME_STOP_REQ_CMD:
  		/* prepare stop request */
  		mei_hdr = (struct mei_msg_hdr *) &dev->ext_msg_buf[0];
  		mei_hdr->host_addr = 0;
  		mei_hdr->me_addr = 0;
  		mei_hdr->length = sizeof(struct hbm_host_stop_request);
  		mei_hdr->msg_complete = 1;
  		mei_hdr->reserved = 0;
  		host_stop_req =
  			(struct hbm_host_stop_request *) &dev->ext_msg_buf[1];
  		memset(host_stop_req, 0, sizeof(struct hbm_host_stop_request));
  		host_stop_req->hbm_cmd = HOST_STOP_REQ_CMD;
  		host_stop_req->reason = DRIVER_STOP_REQUEST;
  		host_stop_req->reserved[0] = 0;
  		host_stop_req->reserved[1] = 0;
  		dev->extra_write_index = 2;
  		break;
  
  	default:
  		BUG();
  		break;
  
  	}
  }
  
  
  /**
   * _mei_hb_read - processes read related operation.
   *
   * @dev: the device structure.
   * @slots: free slots.
   * @cb_pos: callback block.
   * @cl: private data of the file object.
   * @cmpl_list: complete list.
   *
   * returns 0, OK; otherwise, error.
   */
  static int _mei_irq_thread_read(struct mei_device *dev,	s32 *slots,
  			struct mei_cl_cb *cb_pos,
  			struct mei_cl *cl,
  			struct mei_io_list *cmpl_list)
  {
  	if ((*slots * sizeof(u32)) < (sizeof(struct mei_msg_hdr) +
  			sizeof(struct hbm_flow_control))) {
  		/* return the cancel routine */
  		list_del(&cb_pos->cb_list);
  		return -EBADMSG;
  	}
  
  	*slots -= mei_data2slots(sizeof(struct hbm_flow_control));
  
  	if (mei_send_flow_control(dev, cl)) {
  		cl->status = -ENODEV;
  		cb_pos->information = 0;
  		list_move_tail(&cb_pos->cb_list, &cmpl_list->mei_cb.cb_list);
  		return -ENODEV;
  	}
  	list_move_tail(&cb_pos->cb_list, &dev->read_list.mei_cb.cb_list);
  
  	return 0;
  }
  
  
  /**
   * _mei_irq_thread_ioctl - processes ioctl related operation.
   *
   * @dev: the device structure.
   * @slots: free slots.
   * @cb_pos: callback block.
   * @cl: private data of the file object.
   * @cmpl_list: complete list.
   *
   * returns 0, OK; otherwise, error.
   */
  static int _mei_irq_thread_ioctl(struct mei_device *dev, s32 *slots,
  			struct mei_cl_cb *cb_pos,
  			struct mei_cl *cl,
  			struct mei_io_list *cmpl_list)
  {
  	if ((*slots * sizeof(u32)) < (sizeof(struct mei_msg_hdr) +
  			sizeof(struct hbm_client_connect_request))) {
  		/* return the cancel routine */
  		list_del(&cb_pos->cb_list);
  		return -EBADMSG;
  	}
  
  	cl->state = MEI_FILE_CONNECTING;
  	 *slots -= mei_data2slots(sizeof(struct hbm_client_connect_request));
  	if (mei_connect(dev, cl)) {
  		cl->status = -ENODEV;
  		cb_pos->information = 0;
  		list_del(&cb_pos->cb_list);
  		return -ENODEV;
  	} else {
  		list_move_tail(&cb_pos->cb_list,
  			&dev->ctrl_rd_list.mei_cb.cb_list);
  		cl->timer_count = MEI_CONNECT_TIMEOUT;
  	}
  	return 0;
  }
  
  /**
   * _mei_irq_thread_cmpl - processes completed and no-iamthif operation.
   *
   * @dev: the device structure.
   * @slots: free slots.
   * @cb_pos: callback block.
   * @cl: private data of the file object.
   * @cmpl_list: complete list.
   *
   * returns 0, OK; otherwise, error.
   */
  static int _mei_irq_thread_cmpl(struct mei_device *dev,	s32 *slots,
  			struct mei_cl_cb *cb_pos,
  			struct mei_cl *cl,
  			struct mei_io_list *cmpl_list)
  {
  	struct mei_msg_hdr *mei_hdr;
  
  	if ((*slots * sizeof(u32)) >= (sizeof(struct mei_msg_hdr) +
  			(cb_pos->request_buffer.size -
  			cb_pos->information))) {
  		mei_hdr = (struct mei_msg_hdr *) &dev->wr_msg_buf[0];
  		mei_hdr->host_addr = cl->host_client_id;
  		mei_hdr->me_addr = cl->me_client_id;
  		mei_hdr->length = cb_pos->request_buffer.size -
  					cb_pos->information;
  		mei_hdr->msg_complete = 1;
  		mei_hdr->reserved = 0;
  		dev_dbg(&dev->pdev->dev, "cb_pos->request_buffer.size =%d"
  			"mei_hdr->msg_complete = %d\n",
  				cb_pos->request_buffer.size,
  				mei_hdr->msg_complete);
  		dev_dbg(&dev->pdev->dev, "cb_pos->information  =%lu\n",
  				cb_pos->information);
  		dev_dbg(&dev->pdev->dev, "mei_hdr->length  =%d\n",
  				mei_hdr->length);
  		*slots -= mei_data2slots(mei_hdr->length);
  		if (mei_write_message(dev, mei_hdr,
  				(unsigned char *)
  				(cb_pos->request_buffer.data +
  				cb_pos->information),
  				mei_hdr->length)) {
  			cl->status = -ENODEV;
  			list_move_tail(&cb_pos->cb_list,
  				&cmpl_list->mei_cb.cb_list);
  			return -ENODEV;
  		} else {
  			if (mei_flow_ctrl_reduce(dev, cl))
  				return -ENODEV;
  			cl->status = 0;
  			cb_pos->information += mei_hdr->length;
  			list_move_tail(&cb_pos->cb_list,
  				&dev->write_waiting_list.mei_cb.cb_list);
  		}
  	} else if (*slots == dev->hbuf_depth) {
  		/* buffer is still empty */
  		mei_hdr = (struct mei_msg_hdr *) &dev->wr_msg_buf[0];
  		mei_hdr->host_addr = cl->host_client_id;
  		mei_hdr->me_addr = cl->me_client_id;
  		mei_hdr->length =
  			(*slots * sizeof(u32)) - sizeof(struct mei_msg_hdr);
  		mei_hdr->msg_complete = 0;
  		mei_hdr->reserved = 0;
  		*slots -= mei_data2slots(mei_hdr->length);
  		if (mei_write_message(dev, mei_hdr,
  					(unsigned char *)
  					(cb_pos->request_buffer.data +
  					cb_pos->information),
  					mei_hdr->length)) {
  			cl->status = -ENODEV;
  			list_move_tail(&cb_pos->cb_list,
  				&cmpl_list->mei_cb.cb_list);
  			return -ENODEV;
  		} else {
  			cb_pos->information += mei_hdr->length;
  			dev_dbg(&dev->pdev->dev,
  					"cb_pos->request_buffer.size =%d"
  					" mei_hdr->msg_complete = %d\n",
  					cb_pos->request_buffer.size,
  					mei_hdr->msg_complete);
  			dev_dbg(&dev->pdev->dev, "cb_pos->information  =%lu\n",
  					cb_pos->information);
  			dev_dbg(&dev->pdev->dev, "mei_hdr->length  =%d\n",
  					mei_hdr->length);
  		}
  		return -EMSGSIZE;
  	} else {
  		return -EBADMSG;
  	}
  
  	return 0;
  }
  
  /**
   * _mei_irq_thread_cmpl_iamthif - processes completed iamthif operation.
   *
   * @dev: the device structure.
   * @slots: free slots.
   * @cb_pos: callback block.
   * @cl: private data of the file object.
   * @cmpl_list: complete list.
   *
   * returns 0, OK; otherwise, error.
   */
  static int _mei_irq_thread_cmpl_iamthif(struct mei_device *dev, s32 *slots,
  			struct mei_cl_cb *cb_pos,
  			struct mei_cl *cl,
  			struct mei_io_list *cmpl_list)
  {
  	struct mei_msg_hdr *mei_hdr;
  
  	if ((*slots * sizeof(u32)) >= (sizeof(struct mei_msg_hdr) +
  			dev->iamthif_msg_buf_size -
  			dev->iamthif_msg_buf_index)) {
  		mei_hdr = (struct mei_msg_hdr *) &dev->wr_msg_buf[0];
  		mei_hdr->host_addr = cl->host_client_id;
  		mei_hdr->me_addr = cl->me_client_id;
  		mei_hdr->length = dev->iamthif_msg_buf_size -
  			dev->iamthif_msg_buf_index;
  		mei_hdr->msg_complete = 1;
  		mei_hdr->reserved = 0;
  
  		*slots -= mei_data2slots(mei_hdr->length);
  
  		if (mei_write_message(dev, mei_hdr,
  					(dev->iamthif_msg_buf +
  					dev->iamthif_msg_buf_index),
  					mei_hdr->length)) {
  			dev->iamthif_state = MEI_IAMTHIF_IDLE;
  			cl->status = -ENODEV;
  			list_del(&cb_pos->cb_list);
  			return -ENODEV;
  		} else {
  			if (mei_flow_ctrl_reduce(dev, cl))
  				return -ENODEV;
  			dev->iamthif_msg_buf_index += mei_hdr->length;
  			cb_pos->information = dev->iamthif_msg_buf_index;
  			cl->status = 0;
  			dev->iamthif_state = MEI_IAMTHIF_FLOW_CONTROL;
  			dev->iamthif_flow_control_pending = true;
  			/* save iamthif cb sent to amthi client */
  			dev->iamthif_current_cb = cb_pos;
  			list_move_tail(&cb_pos->cb_list,
  				&dev->write_waiting_list.mei_cb.cb_list);
  
  		}
  	} else if (*slots == dev->hbuf_depth) {
  		/* buffer is still empty */
  		mei_hdr = (struct mei_msg_hdr *) &dev->wr_msg_buf[0];
  		mei_hdr->host_addr = cl->host_client_id;
  		mei_hdr->me_addr = cl->me_client_id;
  		mei_hdr->length =
  			(*slots * sizeof(u32)) - sizeof(struct mei_msg_hdr);
  		mei_hdr->msg_complete = 0;
  		mei_hdr->reserved = 0;
  
  		*slots -= mei_data2slots(mei_hdr->length);
  
  		if (mei_write_message(dev, mei_hdr,
  					(dev->iamthif_msg_buf +
  					dev->iamthif_msg_buf_index),
  					mei_hdr->length)) {
  			cl->status = -ENODEV;
  			list_del(&cb_pos->cb_list);
  		} else {
  			dev->iamthif_msg_buf_index += mei_hdr->length;
  		}
  		return -EMSGSIZE;
  	} else {
  		return -EBADMSG;
  	}
  
  	return 0;
  }
  
  /**
   * mei_irq_thread_read_handler - bottom half read routine after ISR to
   * handle the read processing.
   *
   * @cmpl_list: An instance of our list structure
   * @dev: the device structure
   * @slots: slots to read.
   *
   * returns 0 on success, <0 on failure.
   */
  static int mei_irq_thread_read_handler(struct mei_io_list *cmpl_list,
  		struct mei_device *dev,
  		s32 *slots)
  {
  	struct mei_msg_hdr *mei_hdr;
  	struct mei_cl *cl_pos = NULL;
  	struct mei_cl *cl_next = NULL;
  	int ret = 0;
  
  	if (!dev->rd_msg_hdr) {
  		dev->rd_msg_hdr = mei_mecbrw_read(dev);
  		dev_dbg(&dev->pdev->dev, "slots =%08x.\n", *slots);
  		(*slots)--;
  		dev_dbg(&dev->pdev->dev, "slots =%08x.\n", *slots);
  	}
  	mei_hdr = (struct mei_msg_hdr *) &dev->rd_msg_hdr;
  	dev_dbg(&dev->pdev->dev, "mei_hdr->length =%d\n", mei_hdr->length);
  
  	if (mei_hdr->reserved || !dev->rd_msg_hdr) {
  		dev_dbg(&dev->pdev->dev, "corrupted message header.\n");
  		ret = -EBADMSG;
  		goto end;
  	}
  
  	if (mei_hdr->host_addr || mei_hdr->me_addr) {
  		list_for_each_entry_safe(cl_pos, cl_next,
  					&dev->file_list, link) {
  			dev_dbg(&dev->pdev->dev,
  					"list_for_each_entry_safe read host"
  					" client = %d, ME client = %d\n",
  					cl_pos->host_client_id,
  					cl_pos->me_client_id);
  			if (cl_pos->host_client_id == mei_hdr->host_addr &&
  			    cl_pos->me_client_id == mei_hdr->me_addr)
  				break;
  		}
  
  		if (&cl_pos->link == &dev->file_list) {
  			dev_dbg(&dev->pdev->dev, "corrupted message header\n");
  			ret = -EBADMSG;
  			goto end;
  		}
  	}
  	if (((*slots) * sizeof(u32)) < mei_hdr->length) {
  		dev_dbg(&dev->pdev->dev,
  				"we can't read the message slots =%08x.\n",
  				*slots);
  		/* we can't read the message */
  		ret = -ERANGE;
  		goto end;
  	}
  
  	/* decide where to read the message too */
  	if (!mei_hdr->host_addr) {
  		dev_dbg(&dev->pdev->dev, "call mei_irq_thread_read_bus_message.\n");
  		mei_irq_thread_read_bus_message(dev, mei_hdr);
  		dev_dbg(&dev->pdev->dev, "end mei_irq_thread_read_bus_message.\n");
  	} else if (mei_hdr->host_addr == dev->iamthif_cl.host_client_id &&
  		   (MEI_FILE_CONNECTED == dev->iamthif_cl.state) &&
  		   (dev->iamthif_state == MEI_IAMTHIF_READING)) {
  		dev_dbg(&dev->pdev->dev, "call mei_irq_thread_read_iamthif_message.\n");
  		dev_dbg(&dev->pdev->dev, "mei_hdr->length =%d\n",
  				mei_hdr->length);
  		ret = mei_irq_thread_read_amthi_message(cmpl_list,
  							dev, mei_hdr);
  		if (ret)
  			goto end;
  
  	} else {
  		dev_dbg(&dev->pdev->dev, "call mei_irq_thread_read_client_message.\n");
  		ret = mei_irq_thread_read_client_message(cmpl_list,
  							 dev, mei_hdr);
  		if (ret)
  			goto end;
  
  	}
  
  	/* reset the number of slots and header */
  	*slots = mei_count_full_read_slots(dev);
  	dev->rd_msg_hdr = 0;
  
  	if (*slots == -EOVERFLOW) {
  		/* overflow - reset */
  		dev_dbg(&dev->pdev->dev, "resetting due to slots overflow.\n");
  		/* set the event since message has been read */
  		ret = -ERANGE;
  		goto end;
  	}
  end:
  	return ret;
  }
  
  
  /**
   * mei_irq_thread_write_handler - bottom half write routine after
   * ISR to handle the write processing.
   *
   * @cmpl_list: An instance of our list structure
   * @dev: the device structure
   * @slots: slots to write.
   *
   * returns 0 on success, <0 on failure.
   */
  static int mei_irq_thread_write_handler(struct mei_io_list *cmpl_list,
  		struct mei_device *dev,
  		s32 *slots)
  {
  
  	struct mei_cl *cl;
  	struct mei_cl_cb *pos = NULL, *next = NULL;
  	struct mei_io_list *list;
  	int ret;
  
  	if (!mei_hbuf_is_empty(dev)) {
  		dev_dbg(&dev->pdev->dev, "host buffer is not empty.\n");
  		return 0;
  	}
  	*slots = mei_hbuf_empty_slots(dev);
  	if (*slots <= 0)
  		return -EMSGSIZE;
  
  	/* complete all waiting for write CB */
  	dev_dbg(&dev->pdev->dev, "complete all waiting for write cb.\n");
  
  	list = &dev->write_waiting_list;
  	list_for_each_entry_safe(pos, next, &list->mei_cb.cb_list, cb_list) {
  		cl = (struct mei_cl *)pos->file_private;
  		if (cl == NULL)
  			continue;
  
  		cl->status = 0;
  		list_del(&pos->cb_list);
  		if (MEI_WRITING == cl->writing_state &&
  		   (pos->major_file_operations == MEI_WRITE) &&
  		   (cl != &dev->iamthif_cl)) {
  			dev_dbg(&dev->pdev->dev, "MEI WRITE COMPLETE\n");
  			cl->writing_state = MEI_WRITE_COMPLETE;
  			list_add_tail(&pos->cb_list,
  				      &cmpl_list->mei_cb.cb_list);
  		}
  		if (cl == &dev->iamthif_cl) {
  			dev_dbg(&dev->pdev->dev, "check iamthif flow control.\n");
  			if (dev->iamthif_flow_control_pending) {
  				ret = _mei_irq_thread_iamthif_read(dev, slots);
  				if (ret)
  					return ret;
  			}
  		}
  	}
  
  	if (dev->wd_state == MEI_WD_STOPPING) {
  		dev->wd_state = MEI_WD_IDLE;
  		wake_up_interruptible(&dev->wait_stop_wd);
  	}
  
  	if (dev->extra_write_index) {
  		dev_dbg(&dev->pdev->dev, "extra_write_index =%d.\n",
  				dev->extra_write_index);
  		mei_write_message(dev,
  				(struct mei_msg_hdr *) &dev->ext_msg_buf[0],
  				(unsigned char *) &dev->ext_msg_buf[1],
  				(dev->extra_write_index - 1) * sizeof(u32));
  		*slots -= dev->extra_write_index;
  		dev->extra_write_index = 0;
  	}
  	if (dev->dev_state == MEI_DEV_ENABLED) {
  		if (dev->wd_pending &&
  		    mei_flow_ctrl_creds(dev, &dev->wd_cl) > 0) {
  			if (mei_wd_send(dev))
  				dev_dbg(&dev->pdev->dev, "wd send failed.\n");
  			else if (mei_flow_ctrl_reduce(dev, &dev->wd_cl))
  				return -ENODEV;
  
  			dev->wd_pending = false;
  
  			if (dev->wd_state == MEI_WD_RUNNING)
  				*slots -= mei_data2slots(MEI_WD_START_MSG_SIZE);
  			else
  				*slots -= mei_data2slots(MEI_WD_STOP_MSG_SIZE);
  		}
  	}
  
  	/* complete control write list CB */
  	dev_dbg(&dev->pdev->dev, "complete control write list cb.\n");
  	list_for_each_entry_safe(pos, next,
  				&dev->ctrl_wr_list.mei_cb.cb_list, cb_list) {
  		cl = (struct mei_cl *) pos->file_private;
  		if (!cl) {
  			list_del(&pos->cb_list);
  			return -ENODEV;
  		}
  		switch (pos->major_file_operations) {
  		case MEI_CLOSE:
  			/* send disconnect message */
  			ret = _mei_irq_thread_close(dev, slots, pos, cl, cmpl_list);
  			if (ret)
  				return ret;
  
  			break;
  		case MEI_READ:
  			/* send flow control message */
  			ret = _mei_irq_thread_read(dev, slots, pos, cl, cmpl_list);
  			if (ret)
  				return ret;
  
  			break;
  		case MEI_IOCTL:
  			/* connect message */
  			if (mei_other_client_is_connecting(dev, cl))
  				continue;
  			ret = _mei_irq_thread_ioctl(dev, slots, pos, cl, cmpl_list);
  			if (ret)
  				return ret;
  
  			break;
  
  		default:
  			BUG();
  		}
  
  	}
  	/* complete  write list CB */
  	dev_dbg(&dev->pdev->dev, "complete write list cb.\n");
  	list_for_each_entry_safe(pos, next,
  				&dev->write_list.mei_cb.cb_list, cb_list) {
  		cl = (struct mei_cl *)pos->file_private;
  		if (cl == NULL)
  			continue;
  
  		if (cl != &dev->iamthif_cl) {
  			if (mei_flow_ctrl_creds(dev, cl) <= 0) {
  				dev_dbg(&dev->pdev->dev,
  					"No flow control credentials for client %d, not sending.\n",
  					cl->host_client_id);
  				continue;
  			}
  			ret = _mei_irq_thread_cmpl(dev, slots, pos,
  						cl, cmpl_list);
  			if (ret)
  				return ret;
  
  		} else if (cl == &dev->iamthif_cl) {
  			/* IAMTHIF IOCTL */
  			dev_dbg(&dev->pdev->dev, "complete amthi write cb.\n");
  			if (mei_flow_ctrl_creds(dev, cl) <= 0) {
  				dev_dbg(&dev->pdev->dev,
  					"No flow control credentials for amthi client %d.\n",
  					cl->host_client_id);
  				continue;
  			}
  			ret = _mei_irq_thread_cmpl_iamthif(dev, slots, pos,
  						cl, cmpl_list);
  			if (ret)
  				return ret;
  
  		}
  
  	}
  	return 0;
  }
  
  
  
  /**
   * mei_timer - timer function.
   *
   * @work: pointer to the work_struct structure
   *
   * NOTE: This function is called by timer interrupt work
   */
  void mei_timer(struct work_struct *work)
  {
  	unsigned long timeout;
  	struct mei_cl *cl_pos = NULL;
  	struct mei_cl *cl_next = NULL;
  	struct list_head *amthi_complete_list = NULL;
  	struct mei_cl_cb  *cb_pos = NULL;
  	struct mei_cl_cb  *cb_next = NULL;
  
  	struct mei_device *dev = container_of(work,
  					struct mei_device, timer_work.work);
  
  
  	mutex_lock(&dev->device_lock);
  	if (dev->dev_state != MEI_DEV_ENABLED) {
  		if (dev->dev_state == MEI_DEV_INIT_CLIENTS) {
  			if (dev->init_clients_timer) {
  				if (--dev->init_clients_timer == 0) {
  					dev_dbg(&dev->pdev->dev, "IMEI reset due to init clients timeout ,init clients state = %d.\n",
  						dev->init_clients_state);
  					mei_reset(dev, 1);
  				}
  			}
  		}
  		goto out;
  	}
  	/*** connect/disconnect timeouts ***/
  	list_for_each_entry_safe(cl_pos, cl_next, &dev->file_list, link) {
  		if (cl_pos->timer_count) {
  			if (--cl_pos->timer_count == 0) {
  				dev_dbg(&dev->pdev->dev, "HECI reset due to connect/disconnect timeout.\n");
  				mei_reset(dev, 1);
  				goto out;
  			}
  		}
  	}
  
  	if (dev->iamthif_stall_timer) {
  		if (--dev->iamthif_stall_timer == 0) {
  			dev_dbg(&dev->pdev->dev, "resetting because of hang to amthi.\n");
  			mei_reset(dev, 1);
  			dev->iamthif_msg_buf_size = 0;
  			dev->iamthif_msg_buf_index = 0;
  			dev->iamthif_canceled = false;
  			dev->iamthif_ioctl = true;
  			dev->iamthif_state = MEI_IAMTHIF_IDLE;
  			dev->iamthif_timer = 0;
  
  			if (dev->iamthif_current_cb)
  				mei_free_cb_private(dev->iamthif_current_cb);
  
  			dev->iamthif_file_object = NULL;
  			dev->iamthif_current_cb = NULL;
  			mei_run_next_iamthif_cmd(dev);
  		}
  	}
  
  	if (dev->iamthif_timer) {
  
  		timeout = dev->iamthif_timer +
  				msecs_to_jiffies(IAMTHIF_READ_TIMER);
  
  		dev_dbg(&dev->pdev->dev, "dev->iamthif_timer = %ld\n",
  				dev->iamthif_timer);
  		dev_dbg(&dev->pdev->dev, "timeout = %ld\n", timeout);
  		dev_dbg(&dev->pdev->dev, "jiffies = %ld\n", jiffies);
  		if (time_after(jiffies, timeout)) {
  			/*
  			 * User didn't read the AMTHI data on time (15sec)
  			 * freeing AMTHI for other requests
  			 */
  
  			dev_dbg(&dev->pdev->dev, "freeing AMTHI for other requests\n");
  
  			amthi_complete_list = &dev->amthi_read_complete_list.
  					mei_cb.cb_list;
  
  			list_for_each_entry_safe(cb_pos, cb_next, amthi_complete_list, cb_list) {
  
  				cl_pos = cb_pos->file_object->private_data;
  
  				/* Finding the AMTHI entry. */
  				if (cl_pos == &dev->iamthif_cl)
  					list_del(&cb_pos->cb_list);
  			}
  			if (dev->iamthif_current_cb)
  				mei_free_cb_private(dev->iamthif_current_cb);
  
  			dev->iamthif_file_object->private_data = NULL;
  			dev->iamthif_file_object = NULL;
  			dev->iamthif_current_cb = NULL;
  			dev->iamthif_timer = 0;
  			mei_run_next_iamthif_cmd(dev);
  
  		}
  	}
  out:
  	schedule_delayed_work(&dev->timer_work, 2 * HZ);
  	mutex_unlock(&dev->device_lock);
  }
  
  /**
   *  mei_interrupt_thread_handler - function called after ISR to handle the interrupt
   * processing.
   *
   * @irq: The irq number
   * @dev_id: pointer to the device structure
   *
   * returns irqreturn_t
   *
   */
  irqreturn_t mei_interrupt_thread_handler(int irq, void *dev_id)
  {
  	struct mei_device *dev = (struct mei_device *) dev_id;
  	struct mei_io_list complete_list;
  	struct mei_cl_cb *cb_pos = NULL, *cb_next = NULL;
  	struct mei_cl *cl;
  	s32 slots;
  	int rets;
  	bool  bus_message_received;
  
  
  	dev_dbg(&dev->pdev->dev, "function called after ISR to handle the interrupt processing.\n");
  	/* initialize our complete list */
  	mutex_lock(&dev->device_lock);
  	mei_io_list_init(&complete_list);
  	dev->host_hw_state = mei_hcsr_read(dev);
  
  	/* Ack the interrupt here
  	 * In case of MSI we don't go through the quick handler */
  	if (pci_dev_msi_enabled(dev->pdev))
  		mei_reg_write(dev, H_CSR, dev->host_hw_state);
  
  	dev->me_hw_state = mei_mecsr_read(dev);
  
  	/* check if ME wants a reset */
  	if ((dev->me_hw_state & ME_RDY_HRA) == 0 &&
  	    dev->dev_state != MEI_DEV_RESETING &&
  	    dev->dev_state != MEI_DEV_INITIALIZING) {
  		dev_dbg(&dev->pdev->dev, "FW not ready.\n");
  		mei_reset(dev, 1);
  		mutex_unlock(&dev->device_lock);
  		return IRQ_HANDLED;
  	}
  
  	/*  check if we need to start the dev */
  	if ((dev->host_hw_state & H_RDY) == 0) {
  		if ((dev->me_hw_state & ME_RDY_HRA) == ME_RDY_HRA) {
  			dev_dbg(&dev->pdev->dev, "we need to start the dev.\n");
  			dev->host_hw_state |= (H_IE | H_IG | H_RDY);
  			mei_hcsr_set(dev);
  			dev->dev_state = MEI_DEV_INIT_CLIENTS;
  			dev_dbg(&dev->pdev->dev, "link is established start sending messages.\n");
  			/* link is established
  			 * start sending messages.
  			 */
  			mei_host_start_message(dev);
  			mutex_unlock(&dev->device_lock);
  			return IRQ_HANDLED;
  		} else {
  			dev_dbg(&dev->pdev->dev, "FW not ready.\n");
  			mutex_unlock(&dev->device_lock);
  			return IRQ_HANDLED;
  		}
  	}
  	/* check slots available for reading */
  	slots = mei_count_full_read_slots(dev);
  	dev_dbg(&dev->pdev->dev, "slots =%08x  extra_write_index =%08x.\n",
  		slots, dev->extra_write_index);
  	while (slots > 0 && !dev->extra_write_index) {
  		dev_dbg(&dev->pdev->dev, "slots =%08x  extra_write_index =%08x.\n",
  				slots, dev->extra_write_index);
  		dev_dbg(&dev->pdev->dev, "call mei_irq_thread_read_handler.\n");
  		rets = mei_irq_thread_read_handler(&complete_list, dev, &slots);
  		if (rets)
  			goto end;
  	}
  	rets = mei_irq_thread_write_handler(&complete_list, dev, &slots);
  end:
  	dev_dbg(&dev->pdev->dev, "end of bottom half function.\n");
  	dev->host_hw_state = mei_hcsr_read(dev);
  	dev->mei_host_buffer_is_empty = mei_hbuf_is_empty(dev);
  
  	bus_message_received = false;
  	if (dev->recvd_msg && waitqueue_active(&dev->wait_recvd_msg)) {
  		dev_dbg(&dev->pdev->dev, "received waiting bus message\n");
  		bus_message_received = true;
  	}
  	mutex_unlock(&dev->device_lock);
  	if (bus_message_received) {
  		dev_dbg(&dev->pdev->dev, "wake up dev->wait_recvd_msg\n");
  		wake_up_interruptible(&dev->wait_recvd_msg);
  		bus_message_received = false;
  	}
  	if (list_empty(&complete_list.mei_cb.cb_list))
  		return IRQ_HANDLED;
  
  
  	list_for_each_entry_safe(cb_pos, cb_next,
  			&complete_list.mei_cb.cb_list, cb_list) {
  		cl = (struct mei_cl *)cb_pos->file_private;
  		list_del(&cb_pos->cb_list);
  		if (cl) {
  			if (cl != &dev->iamthif_cl) {
  				dev_dbg(&dev->pdev->dev, "completing call back.\n");
  				_mei_cmpl(cl, cb_pos);
  				cb_pos = NULL;
  			} else if (cl == &dev->iamthif_cl) {
  				_mei_cmpl_iamthif(dev, cb_pos);
  			}
  		}
  	}
  	return IRQ_HANDLED;
  }
  