drivers/misc/mei/interface.c - kernel/msm-4.19 - Gitiles

 /*
  *
  * 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 "mei_dev.h"
 #include <linux/mei.h>
 #include "interface.h"


 /**
  * mei_set_csr_register - writes H_CSR register to the mei device,
  * and ignores the H_IS bit for it is write-one-to-zero.
  *
  * @dev: the device structure
  */
 void mei_hcsr_set(struct mei_device *dev)
 {
 	if ((dev->host_hw_state & H_IS) == H_IS)
 		dev->host_hw_state &= ~H_IS;
 	mei_reg_write(dev, H_CSR, dev->host_hw_state);
 	dev->host_hw_state = mei_hcsr_read(dev);
 }

 /**
  * mei_csr_enable_interrupts - enables mei device interrupts
  *
  * @dev: the device structure
  */
 void mei_enable_interrupts(struct mei_device *dev)
 {
 	dev->host_hw_state |= H_IE;
 	mei_hcsr_set(dev);
 }

 /**
  * mei_csr_disable_interrupts - disables mei device interrupts
  *
  * @dev: the device structure
  */
 void mei_disable_interrupts(struct mei_device *dev)
 {
 	dev->host_hw_state &= ~H_IE;
 	mei_hcsr_set(dev);
 }

 /**
  * mei_hbuf_filled_slots - gets number of device filled buffer slots
  *
  * @device: the device structure
  *
  * returns number of filled slots
  */
 static unsigned char mei_hbuf_filled_slots(struct mei_device *dev)
 {
 	char read_ptr, write_ptr;

 	dev->host_hw_state = mei_hcsr_read(dev);

 	read_ptr = (char) ((dev->host_hw_state & H_CBRP) >> 8);
 	write_ptr = (char) ((dev->host_hw_state & H_CBWP) >> 16);

 	return (unsigned char) (write_ptr - read_ptr);
 }

 /**
  * mei_hbuf_is_empty - checks if host buffer is empty.
  *
  * @dev: the device structure
  *
  * returns true if empty, false - otherwise.
  */
 bool mei_hbuf_is_empty(struct mei_device *dev)
 {
 	return mei_hbuf_filled_slots(dev) == 0;
 }

 /**
  * mei_hbuf_empty_slots - counts write empty slots.
  *
  * @dev: the device structure
  *
  * returns -1(ESLOTS_OVERFLOW) if overflow, otherwise empty slots count
  */
 int mei_hbuf_empty_slots(struct mei_device *dev)
 {
 	unsigned char filled_slots, empty_slots;

 	filled_slots = mei_hbuf_filled_slots(dev);
 	empty_slots = dev->hbuf_depth - filled_slots;

 	/* check for overflow */
 	if (filled_slots > dev->hbuf_depth)
 		return -EOVERFLOW;

 	return empty_slots;
 }

 /**
  * mei_write_message - writes a message to mei device.
  *
  * @dev: the device structure
  * @header: header of message
  * @write_buffer: message buffer will be written
  * @write_length: message size will be written
  *
  * This function returns -EIO if write has failed
  */
 int mei_write_message(struct mei_device *dev, struct mei_msg_hdr *header,
 		      unsigned char *buf, unsigned long length)
 {
 	unsigned long rem, dw_cnt;
 	u32 *reg_buf = (u32 *)buf;
 	int i;
 	int empty_slots;


 	dev_dbg(&dev->pdev->dev,
 			"mei_write_message header=%08x.\n",
 			*((u32 *) header));

 	empty_slots = mei_hbuf_empty_slots(dev);
 	dev_dbg(&dev->pdev->dev, "empty slots = %hu.\n", empty_slots);

 	dw_cnt = mei_data2slots(length);
 	if (empty_slots < 0 || dw_cnt > empty_slots)
 		return -EIO;

 	mei_reg_write(dev, H_CB_WW, *((u32 *) header));

 	for (i = 0; i < length / 4; i++)
 		mei_reg_write(dev, H_CB_WW, reg_buf[i]);

 	rem = length & 0x3;
 	if (rem > 0) {
 		u32 reg = 0;
 		memcpy(&reg, &buf[length - rem], rem);
 		mei_reg_write(dev, H_CB_WW, reg);
 	}

 	dev->host_hw_state = mei_hcsr_read(dev);
 	dev->host_hw_state |= H_IG;
 	mei_hcsr_set(dev);
 	dev->me_hw_state = mei_mecsr_read(dev);
 	if ((dev->me_hw_state & ME_RDY_HRA) != ME_RDY_HRA)
 		return -EIO;

 	return 0;
 }

 /**
  * mei_count_full_read_slots - counts read full slots.
  *
  * @dev: the device structure
  *
  * returns -1(ESLOTS_OVERFLOW) if overflow, otherwise filled slots count
  */
 int mei_count_full_read_slots(struct mei_device *dev)
 {
 	char read_ptr, write_ptr;
 	unsigned char buffer_depth, filled_slots;

 	dev->me_hw_state = mei_mecsr_read(dev);
 	buffer_depth = (unsigned char)((dev->me_hw_state & ME_CBD_HRA) >> 24);
 	read_ptr = (char) ((dev->me_hw_state & ME_CBRP_HRA) >> 8);
 	write_ptr = (char) ((dev->me_hw_state & ME_CBWP_HRA) >> 16);
 	filled_slots = (unsigned char) (write_ptr - read_ptr);

 	/* check for overflow */
 	if (filled_slots > buffer_depth)
 		return -EOVERFLOW;

 	dev_dbg(&dev->pdev->dev, "filled_slots =%08x\n", filled_slots);
 	return (int)filled_slots;
 }

 /**
  * mei_read_slots - reads a message from mei device.
  *
  * @dev: the device structure
  * @buffer: message buffer will be written
  * @buffer_length: message size will be read
  */
 void mei_read_slots(struct mei_device *dev, unsigned char *buffer,
 		    unsigned long buffer_length)
 {
 	u32 *reg_buf = (u32 *)buffer;

 	for (; buffer_length >= sizeof(u32); buffer_length -= sizeof(u32))
 		*reg_buf++ = mei_mecbrw_read(dev);

 	if (buffer_length > 0) {
 		u32 reg = mei_mecbrw_read(dev);
 		memcpy(reg_buf, &reg, buffer_length);
 	}

 	dev->host_hw_state |= H_IG;
 	mei_hcsr_set(dev);
 }

 /**
  * mei_flow_ctrl_creds - checks flow_control credentials.
  *
  * @dev: the device structure
  * @cl: private data of the file object
  *
  * returns 1 if mei_flow_ctrl_creds >0, 0 - otherwise.
  *	-ENOENT if mei_cl is not present
  *	-EINVAL if single_recv_buf == 0
  */
 int mei_flow_ctrl_creds(struct mei_device *dev, struct mei_cl *cl)
 {
 	int i;

 	if (!dev->me_clients_num)
 		return 0;

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

 	for (i = 0; i < dev->me_clients_num; i++) {
 		struct mei_me_client  *me_cl = &dev->me_clients[i];
 		if (me_cl->client_id == cl->me_client_id) {
 			if (me_cl->mei_flow_ctrl_creds) {
 				if (WARN_ON(me_cl->props.single_recv_buf == 0))
 					return -EINVAL;
 				return 1;
 			} else {
 				return 0;
 			}
 		}
 	}
 	return -ENOENT;
 }

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

 	if (!dev->me_clients_num)
 		return -ENOENT;

 	for (i = 0; i < dev->me_clients_num; i++) {
 		struct mei_me_client  *me_cl = &dev->me_clients[i];
 		if (me_cl->client_id == cl->me_client_id) {
 			if (me_cl->props.single_recv_buf != 0) {
 				if (WARN_ON(me_cl->mei_flow_ctrl_creds <= 0))
 					return -EINVAL;
 				dev->me_clients[i].mei_flow_ctrl_creds--;
 			} else {
 				if (WARN_ON(cl->mei_flow_ctrl_creds <= 0))
 					return -EINVAL;
 				cl->mei_flow_ctrl_creds--;
 			}
 			return 0;
 		}
 	}
 	return -ENOENT;
 }

 /**
  * mei_send_flow_control - sends flow control to fw.
  *
  * @dev: the device structure
  * @cl: private data of the file object
  *
  * This function returns -EIO on write failure
  */
 int mei_send_flow_control(struct mei_device *dev, struct mei_cl *cl)
 {
 	struct mei_msg_hdr *mei_hdr;
 	struct hbm_flow_control *mei_flow_control;

 	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_flow_control);
 	mei_hdr->msg_complete = 1;
 	mei_hdr->reserved = 0;

 	mei_flow_control = (struct hbm_flow_control *) &dev->wr_msg_buf[1];
 	memset(mei_flow_control, 0, sizeof(*mei_flow_control));
 	mei_flow_control->host_addr = cl->host_client_id;
 	mei_flow_control->me_addr = cl->me_client_id;
 	mei_flow_control->hbm_cmd = MEI_FLOW_CONTROL_CMD;
 	memset(mei_flow_control->reserved, 0,
 			sizeof(mei_flow_control->reserved));
 	dev_dbg(&dev->pdev->dev, "sending flow control host client = %d, ME client = %d\n",
 		cl->host_client_id, cl->me_client_id);

 	return mei_write_message(dev, mei_hdr,
 				(unsigned char *) mei_flow_control,
 				sizeof(struct hbm_flow_control));
 }

 /**
  * mei_other_client_is_connecting - checks if other
  *    client with the same client id is connected.
  *
  * @dev: the device structure
  * @cl: private data of the file object
  *
  * returns 1 if other client is connected, 0 - otherwise.
  */
 int mei_other_client_is_connecting(struct mei_device *dev,
 				struct mei_cl *cl)
 {
 	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 ((cl_pos->state == MEI_FILE_CONNECTING) &&
 			(cl_pos != cl) &&
 			cl->me_client_id == cl_pos->me_client_id)
 			return 1;

 	}
 	return 0;
 }

 /**
  * mei_disconnect - sends disconnect message to fw.
  *
  * @dev: the device structure
  * @cl: private data of the file object
  *
  * This function returns -EIO on write failure
  */
 int mei_disconnect(struct mei_device *dev, struct mei_cl *cl)
 {
 	struct mei_msg_hdr *mei_hdr;
 	struct hbm_client_disconnect_request *mei_cli_disconnect;

 	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_client_disconnect_request);
 	mei_hdr->msg_complete = 1;
 	mei_hdr->reserved = 0;

 	mei_cli_disconnect =
 	    (struct hbm_client_disconnect_request *) &dev->wr_msg_buf[1];
 	memset(mei_cli_disconnect, 0, sizeof(*mei_cli_disconnect));
 	mei_cli_disconnect->host_addr = cl->host_client_id;
 	mei_cli_disconnect->me_addr = cl->me_client_id;
 	mei_cli_disconnect->hbm_cmd = CLIENT_DISCONNECT_REQ_CMD;
 	mei_cli_disconnect->reserved[0] = 0;

 	return mei_write_message(dev, mei_hdr,
 				(unsigned char *) mei_cli_disconnect,
 				sizeof(struct hbm_client_disconnect_request));
 }

 /**
  * mei_connect - sends connect message to fw.
  *
  * @dev: the device structure
  * @cl: private data of the file object
  *
  * This function returns -EIO on write failure
  */
 int mei_connect(struct mei_device *dev, struct mei_cl *cl)
 {
 	struct mei_msg_hdr *mei_hdr;
 	struct hbm_client_connect_request *mei_cli_connect;

 	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_client_connect_request);
 	mei_hdr->msg_complete = 1;
 	mei_hdr->reserved = 0;

 	mei_cli_connect =
 	    (struct hbm_client_connect_request *) &dev->wr_msg_buf[1];
 	mei_cli_connect->host_addr = cl->host_client_id;
 	mei_cli_connect->me_addr = cl->me_client_id;
 	mei_cli_connect->hbm_cmd = CLIENT_CONNECT_REQ_CMD;
 	mei_cli_connect->reserved = 0;

 	return mei_write_message(dev, mei_hdr,
 				(unsigned char *) mei_cli_connect,
 				sizeof(struct hbm_client_connect_request));
 }
	/*
	*
	* 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 "mei_dev.h"
	#include <linux/mei.h>
	#include "interface.h"



	/**
	* mei_set_csr_register - writes H_CSR register to the mei device,
	* and ignores the H_IS bit for it is write-one-to-zero.
	*
	* @dev: the device structure
	*/
	void mei_hcsr_set(struct mei_device *dev)
	{
	if ((dev->host_hw_state & H_IS) == H_IS)
	dev->host_hw_state &= ~H_IS;
	mei_reg_write(dev, H_CSR, dev->host_hw_state);
	dev->host_hw_state = mei_hcsr_read(dev);
	}

	/**
	* mei_csr_enable_interrupts - enables mei device interrupts
	*
	* @dev: the device structure
	*/
	void mei_enable_interrupts(struct mei_device *dev)
	{
	dev->host_hw_state \|= H_IE;
	mei_hcsr_set(dev);
	}

	/**
	* mei_csr_disable_interrupts - disables mei device interrupts
	*
	* @dev: the device structure
	*/
	void mei_disable_interrupts(struct mei_device *dev)
	{
	dev->host_hw_state &= ~H_IE;
	mei_hcsr_set(dev);
	}

	/**
	* mei_hbuf_filled_slots - gets number of device filled buffer slots
	*
	* @device: the device structure
	*
	* returns number of filled slots
	*/
	static unsigned char mei_hbuf_filled_slots(struct mei_device *dev)
	{
	char read_ptr, write_ptr;

	dev->host_hw_state = mei_hcsr_read(dev);

	read_ptr = (char) ((dev->host_hw_state & H_CBRP) >> 8);
	write_ptr = (char) ((dev->host_hw_state & H_CBWP) >> 16);

	return (unsigned char) (write_ptr - read_ptr);
	}

	/**
	* mei_hbuf_is_empty - checks if host buffer is empty.
	*
	* @dev: the device structure
	*
	* returns true if empty, false - otherwise.
	*/
	bool mei_hbuf_is_empty(struct mei_device *dev)
	{
	return mei_hbuf_filled_slots(dev) == 0;
	}

	/**
	* mei_hbuf_empty_slots - counts write empty slots.
	*
	* @dev: the device structure
	*
	* returns -1(ESLOTS_OVERFLOW) if overflow, otherwise empty slots count
	*/
	int mei_hbuf_empty_slots(struct mei_device *dev)
	{
	unsigned char filled_slots, empty_slots;

	filled_slots = mei_hbuf_filled_slots(dev);
	empty_slots = dev->hbuf_depth - filled_slots;

	/* check for overflow */
	if (filled_slots > dev->hbuf_depth)
	return -EOVERFLOW;

	return empty_slots;
	}

	/**
	* mei_write_message - writes a message to mei device.
	*
	* @dev: the device structure
	* @header: header of message
	* @write_buffer: message buffer will be written
	* @write_length: message size will be written
	*
	* This function returns -EIO if write has failed
	*/
	int mei_write_message(struct mei_device dev, struct mei_msg_hdr header,
	unsigned char *buf, unsigned long length)
	{
	unsigned long rem, dw_cnt;
	u32 reg_buf = (u32 )buf;
	int i;
	int empty_slots;


	dev_dbg(&dev->pdev->dev,
	"mei_write_message header=%08x.\n",
	((u32 ) header));

	empty_slots = mei_hbuf_empty_slots(dev);
	dev_dbg(&dev->pdev->dev, "empty slots = %hu.\n", empty_slots);

	dw_cnt = mei_data2slots(length);
	if (empty_slots < 0 \|\| dw_cnt > empty_slots)
	return -EIO;

	mei_reg_write(dev, H_CB_WW, ((u32 ) header));

	for (i = 0; i < length / 4; i++)
	mei_reg_write(dev, H_CB_WW, reg_buf[i]);

	rem = length & 0x3;
	if (rem > 0) {
	u32 reg = 0;
	memcpy(&reg, &buf[length - rem], rem);
	mei_reg_write(dev, H_CB_WW, reg);
	}

	dev->host_hw_state = mei_hcsr_read(dev);
	dev->host_hw_state \|= H_IG;
	mei_hcsr_set(dev);
	dev->me_hw_state = mei_mecsr_read(dev);
	if ((dev->me_hw_state & ME_RDY_HRA) != ME_RDY_HRA)
	return -EIO;

	return 0;
	}

	/**
	* mei_count_full_read_slots - counts read full slots.
	*
	* @dev: the device structure
	*
	* returns -1(ESLOTS_OVERFLOW) if overflow, otherwise filled slots count
	*/
	int mei_count_full_read_slots(struct mei_device *dev)
	{
	char read_ptr, write_ptr;
	unsigned char buffer_depth, filled_slots;

	dev->me_hw_state = mei_mecsr_read(dev);
	buffer_depth = (unsigned char)((dev->me_hw_state & ME_CBD_HRA) >> 24);
	read_ptr = (char) ((dev->me_hw_state & ME_CBRP_HRA) >> 8);
	write_ptr = (char) ((dev->me_hw_state & ME_CBWP_HRA) >> 16);
	filled_slots = (unsigned char) (write_ptr - read_ptr);

	/* check for overflow */
	if (filled_slots > buffer_depth)
	return -EOVERFLOW;

	dev_dbg(&dev->pdev->dev, "filled_slots =%08x\n", filled_slots);
	return (int)filled_slots;
	}

	/**
	* mei_read_slots - reads a message from mei device.
	*
	* @dev: the device structure
	* @buffer: message buffer will be written
	* @buffer_length: message size will be read
	*/
	void mei_read_slots(struct mei_device dev, unsigned char buffer,
	unsigned long buffer_length)
	{
	u32 reg_buf = (u32 )buffer;

	for (; buffer_length >= sizeof(u32); buffer_length -= sizeof(u32))
	*reg_buf++ = mei_mecbrw_read(dev);

	if (buffer_length > 0) {
	u32 reg = mei_mecbrw_read(dev);
	memcpy(reg_buf, &reg, buffer_length);
	}

	dev->host_hw_state \|= H_IG;
	mei_hcsr_set(dev);
	}

	/**
	* mei_flow_ctrl_creds - checks flow_control credentials.
	*
	* @dev: the device structure
	* @cl: private data of the file object
	*
	* returns 1 if mei_flow_ctrl_creds >0, 0 - otherwise.
	* -ENOENT if mei_cl is not present
	* -EINVAL if single_recv_buf == 0
	*/
	int mei_flow_ctrl_creds(struct mei_device dev, struct mei_cl cl)
	{
	int i;

	if (!dev->me_clients_num)
	return 0;

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

	for (i = 0; i < dev->me_clients_num; i++) {
	struct mei_me_client *me_cl = &dev->me_clients[i];
	if (me_cl->client_id == cl->me_client_id) {
	if (me_cl->mei_flow_ctrl_creds) {
	if (WARN_ON(me_cl->props.single_recv_buf == 0))
	return -EINVAL;
	return 1;
	} else {
	return 0;
	}
	}
	}
	return -ENOENT;
	}

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

	if (!dev->me_clients_num)
	return -ENOENT;

	for (i = 0; i < dev->me_clients_num; i++) {
	struct mei_me_client *me_cl = &dev->me_clients[i];
	if (me_cl->client_id == cl->me_client_id) {
	if (me_cl->props.single_recv_buf != 0) {
	if (WARN_ON(me_cl->mei_flow_ctrl_creds <= 0))
	return -EINVAL;
	dev->me_clients[i].mei_flow_ctrl_creds--;
	} else {
	if (WARN_ON(cl->mei_flow_ctrl_creds <= 0))
	return -EINVAL;
	cl->mei_flow_ctrl_creds--;
	}
	return 0;
	}
	}
	return -ENOENT;
	}

	/**
	* mei_send_flow_control - sends flow control to fw.
	*
	* @dev: the device structure
	* @cl: private data of the file object
	*
	* This function returns -EIO on write failure
	*/
	int mei_send_flow_control(struct mei_device dev, struct mei_cl cl)
	{
	struct mei_msg_hdr *mei_hdr;
	struct hbm_flow_control *mei_flow_control;

	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_flow_control);
	mei_hdr->msg_complete = 1;
	mei_hdr->reserved = 0;

	mei_flow_control = (struct hbm_flow_control *) &dev->wr_msg_buf[1];
	memset(mei_flow_control, 0, sizeof(*mei_flow_control));
	mei_flow_control->host_addr = cl->host_client_id;
	mei_flow_control->me_addr = cl->me_client_id;
	mei_flow_control->hbm_cmd = MEI_FLOW_CONTROL_CMD;
	memset(mei_flow_control->reserved, 0,
	sizeof(mei_flow_control->reserved));
	dev_dbg(&dev->pdev->dev, "sending flow control host client = %d, ME client = %d\n",
	cl->host_client_id, cl->me_client_id);

	return mei_write_message(dev, mei_hdr,
	(unsigned char *) mei_flow_control,
	sizeof(struct hbm_flow_control));
	}

	/**
	* mei_other_client_is_connecting - checks if other
	* client with the same client id is connected.
	*
	* @dev: the device structure
	* @cl: private data of the file object
	*
	* returns 1 if other client is connected, 0 - otherwise.
	*/
	int mei_other_client_is_connecting(struct mei_device *dev,
	struct mei_cl *cl)
	{
	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 ((cl_pos->state == MEI_FILE_CONNECTING) &&
	(cl_pos != cl) &&
	cl->me_client_id == cl_pos->me_client_id)
	return 1;

	}
	return 0;
	}

	/**
	* mei_disconnect - sends disconnect message to fw.
	*
	* @dev: the device structure
	* @cl: private data of the file object
	*
	* This function returns -EIO on write failure
	*/
	int mei_disconnect(struct mei_device dev, struct mei_cl cl)
	{
	struct mei_msg_hdr *mei_hdr;
	struct hbm_client_disconnect_request *mei_cli_disconnect;

	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_client_disconnect_request);
	mei_hdr->msg_complete = 1;
	mei_hdr->reserved = 0;

	mei_cli_disconnect =
	(struct hbm_client_disconnect_request *) &dev->wr_msg_buf[1];
	memset(mei_cli_disconnect, 0, sizeof(*mei_cli_disconnect));
	mei_cli_disconnect->host_addr = cl->host_client_id;
	mei_cli_disconnect->me_addr = cl->me_client_id;
	mei_cli_disconnect->hbm_cmd = CLIENT_DISCONNECT_REQ_CMD;
	mei_cli_disconnect->reserved[0] = 0;

	return mei_write_message(dev, mei_hdr,
	(unsigned char *) mei_cli_disconnect,
	sizeof(struct hbm_client_disconnect_request));
	}

	/**
	* mei_connect - sends connect message to fw.
	*
	* @dev: the device structure
	* @cl: private data of the file object
	*
	* This function returns -EIO on write failure
	*/
	int mei_connect(struct mei_device dev, struct mei_cl cl)
	{
	struct mei_msg_hdr *mei_hdr;
	struct hbm_client_connect_request *mei_cli_connect;

	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_client_connect_request);
	mei_hdr->msg_complete = 1;
	mei_hdr->reserved = 0;

	mei_cli_connect =
	(struct hbm_client_connect_request *) &dev->wr_msg_buf[1];
	mei_cli_connect->host_addr = cl->host_client_id;
	mei_cli_connect->me_addr = cl->me_client_id;
	mei_cli_connect->hbm_cmd = CLIENT_CONNECT_REQ_CMD;
	mei_cli_connect->reserved = 0;

	return mei_write_message(dev, mei_hdr,
	(unsigned char *) mei_cli_connect,
	sizeof(struct hbm_client_connect_request));
	}