]> git.karo-electronics.de Git - linux-beck.git/commitdiff
staging/mei: Interrupt handling.
authorOren Weil <oren.jer.weil@intel.com>
Sun, 15 May 2011 10:43:42 +0000 (13:43 +0300)
committerGreg Kroah-Hartman <gregkh@suse.de>
Wed, 18 May 2011 15:30:56 +0000 (08:30 -0700)
ISR and interrupt thread for handling incoming data.
e.g. read bus message, read client message, handle reset requests.

quick handler:
As MEI may share interrupt with GFX and/or USB
the HW register need to be checked and acknowledged.

thread handler:
Check if HW has data for read.
Write data to HW if possible.
May init reset flow on error

there can be two types of messages:
1) bus messages:
Management messages between MEI Driver and ME e.g.
Connect request/response,
Disconnect request/response
Enum clients request/response
Flow control request/response
those message are indicated by
ME Address/ID == 0 && Host Address/ID == 0

2) feature/client messages:
message that are sends between ME Feature/Client and
an application, the struct of the message is defined
by the ME Feature Protocol (e.g. APF Protocol, AMTHI Protocol)
those message are indicated by
ME Address/ID != 0 && Host Address/ID != 0

MEI Initialization state machine is also managed by this patch.
After MEI Reset is preform:
Send Start request
wait for answer
Send Enumerate Clients request
wait for answer
Send Get Client property for each client request
wait for answers
Init Done.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Itzhak Tzeel-Krupp <itzhak.tzeel-krupp@intel.com>
Signed-off-by: Oren Weil <oren.jer.weil@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/staging/mei/interrupt.c [new file with mode: 0644]

diff --git a/drivers/staging/mei/interrupt.c b/drivers/staging/mei/interrupt.c
new file mode 100644 (file)
index 0000000..d1b9214
--- /dev/null
@@ -0,0 +1,1624 @@
+/*
+ *
+ * Intel Management Engine Interface (Intel MEI) Linux driver
+ * Copyright (c) 2003-2011, 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 "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 {
+               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 = (unsigned char *) (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;
+
+       dev_dbg(&dev->pdev->dev, "start client msg\n");
+       if (!(dev->read_list.status == 0 &&
+             !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 = (unsigned char *)
+                               (cb_pos->response_buffer.data +
+                               cb_pos->information);
+                       BUG_ON(cb_pos->response_buffer.size <
+                                       mei_hdr->length +
+                                       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 host client = %d,"
+                                       "ME client = %d, "
+                                       "data length = %lu\n",
+                                       cl->host_client_id,
+                                       cl->me_client_id,
+                                       cb_pos->information);
+
+                               *(cb_pos->response_buffer.data +
+                                       cb_pos->information) = '\0';
+                               dev_dbg(&dev->pdev->dev, "cb_pos->res_buffer - %s\n",
+                                       cb_pos->response_buffer.data);
+                               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, (unsigned char *) 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))) {
+               *slots -= (sizeof(struct mei_msg_hdr) +
+                               sizeof(struct hbm_flow_control) + 3) / 4;
+               if (!mei_send_flow_control(dev, &dev->iamthif_cl)) {
+                       dev_dbg(&dev->pdev->dev, "iamthif flow control failed\n");
+               } else {
+                       dev_dbg(&dev->pdev->dev, "iamthif flow control success\n");
+                       dev->iamthif_state = MEI_IAMTHIF_READING;
+                       dev->iamthif_flow_control_pending = 0;
+                       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_host_buffer_is_empty(dev);
+               }
+               return 0;
+       } else {
+               return -EMSGSIZE;
+       }
+}
+
+/**
+ * _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))) {
+               *slots -= (sizeof(struct mei_msg_hdr) +
+                       sizeof(struct hbm_client_disconnect_request) + 3) / 4;
+
+               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;
+               }
+       } else {
+               /* return the cancel routine */
+               return -EBADMSG;
+       }
+
+       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, "dev->wd_timeout =%d.\n",
+                               dev->wd_timeout);
+
+               dev->wd_due_counter = (dev->wd_timeout) ? 1 : 0;
+
+               dev_dbg(&dev->pdev->dev, "successfully connected to WD client.\n");
+               host_init_iamthif(dev);
+               return;
+       }
+
+       if (is_treat_specially_client(&(dev->iamthif_cl), rs)) {
+               dev->iamthif_state = MEI_IAMTHIF_IDLE;
+               return;
+       }
+       if (!dev->ctrl_rd_list.status &&
+           !list_empty(&dev->ctrl_rd_list.mei_cb.cb_list)) {
+               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);
+
+       if (!dev->ctrl_rd_list.status &&
+           !list_empty(&dev->ctrl_rd_list.mei_cb.cb_list)) {
+               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->num_mei_me_clients; 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_due_counter = 0;
+                               dev->wd_pending = 0;
+                       } 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;
+                       *(u8 *) (&disconnect_res->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;
+
+       unsigned char *buffer;
+
+       /* read the message to our buffer */
+       buffer = (unsigned char *) dev->rd_msg_buf;
+       BUG_ON(mei_hdr->length >= sizeof(dev->rd_msg_buf));
+       mei_read_slots(dev, buffer, mei_hdr->length);
+       mei_msg = (struct mei_bus_message *) buffer;
+
+       switch (*(u8 *) mei_msg) {
+       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->mei_state == MEI_INIT_CLIENTS &&
+                           dev->init_clients_state == MEI_START_MESSAGE) {
+                               dev->init_clients_timer = 0;
+                               host_enum_clients_message(dev);
+                       } else {
+                               dev->recvd_msg = 0;
+                               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->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->cmd.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 = 1;
+               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->mei_state == MEI_INIT_CLIENTS &&
+                           dev->init_clients_state ==
+                                       MEI_CLIENT_PROPERTIES_MESSAGE) {
+                               dev->me_client_index++;
+                               dev->me_client_presentation_num++;
+                               host_client_properties(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->mei_state == MEI_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;
+                               allocate_me_clients_storage(dev);
+                               dev->init_clients_state =
+                                       MEI_CLIENT_PROPERTIES_MESSAGE;
+                               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->mei_state = MEI_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->cmd.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))) {
+               *slots -= (sizeof(struct mei_msg_hdr) +
+                       sizeof(struct hbm_flow_control) + 3) / 4;
+               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;
+               } else {
+                       list_move_tail(&cb_pos->cb_list,
+                                       &dev->read_list.mei_cb.cb_list);
+               }
+       } else {
+               /* return the cancel routine */
+               list_del(&cb_pos->cb_list);
+               return -EBADMSG;
+       }
+
+       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))) {
+               cl->state = MEI_FILE_CONNECTING;
+               *slots -= (sizeof(struct mei_msg_hdr) +
+                       sizeof(struct hbm_client_connect_request) + 3) / 4;
+               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;
+               }
+       } else {
+               /* return the cancel routine */
+               list_del(&cb_pos->cb_list);
+               return -EBADMSG;
+       }
+
+       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 -= (sizeof(struct mei_msg_hdr) +
+                               mei_hdr->length + 3) / 4;
+               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->host_hw_state & H_CBD) >> 24)) {
+               /* 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) -= (sizeof(struct mei_msg_hdr) +
+                               mei_hdr->length + 3) / 4;
+               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 -= (sizeof(struct mei_msg_hdr) +
+                               mei_hdr->length + 3) / 4;
+
+               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 = 1;
+                       /* 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->host_hw_state & H_CBD) >> 24)) {
+                       /* 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 -= (sizeof(struct mei_msg_hdr) +
+                               mei_hdr->length + 3) / 4;
+
+               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 *cb_pos = NULL, *cb_next = NULL;
+       struct mei_io_list *list;
+       int ret;
+
+       if (!mei_host_buffer_is_empty(dev)) {
+               dev_dbg(&dev->pdev->dev, "host buffer is not empty.\n");
+               return 0;
+       }
+       dev->write_hang = -1;
+       *slots = mei_count_empty_write_slots(dev);
+       /* complete all waiting for write CB */
+       dev_dbg(&dev->pdev->dev, "complete all waiting for write cb.\n");
+
+       list = &dev->write_waiting_list;
+       if (!list->status && !list_empty(&list->mei_cb.cb_list)) {
+               list_for_each_entry_safe(cb_pos, cb_next,
+                               &list->mei_cb.cb_list, cb_list) {
+                       cl = (struct mei_cl *)cb_pos->file_private;
+                       if (cl) {
+                               cl->status = 0;
+                               list_del(&cb_pos->cb_list);
+                               if (MEI_WRITING == cl->writing_state &&
+                                  (cb_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(&cb_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->stop && !dev->wd_pending) {
+               dev->wd_stopped = 1;
+               wake_up_interruptible(&dev->wait_stop_wd);
+               return 0;
+       }
+
+       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->mei_state == MEI_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 = 0;
+
+                       if (dev->wd_timeout) {
+                               *slots -= (sizeof(struct mei_msg_hdr) +
+                                        MEI_START_WD_DATA_SIZE + 3) / 4;
+                               dev->wd_due_counter = 2;
+                       } else {
+                               *slots -= (sizeof(struct mei_msg_hdr) +
+                                        MEI_WD_PARAMS_SIZE + 3) / 4;
+                               dev->wd_due_counter = 0;
+                       }
+
+               }
+       }
+       if (dev->stop)
+               return ~ENODEV;
+
+       /* complete control write list CB */
+       if (!dev->ctrl_wr_list.status) {
+               /* complete control write list CB */
+               dev_dbg(&dev->pdev->dev, "complete control write list cb.\n");
+               list_for_each_entry_safe(cb_pos, cb_next,
+                               &dev->ctrl_wr_list.mei_cb.cb_list, cb_list) {
+                       cl = (struct mei_cl *)
+                               cb_pos->file_private;
+                       if (!cl) {
+                               list_del(&cb_pos->cb_list);
+                               return -ENODEV;
+                       }
+                       switch (cb_pos->major_file_operations) {
+                       case MEI_CLOSE:
+                               /* send disconnect message */
+                               ret = _mei_irq_thread_close(dev, slots,
+                                                    cb_pos, cl, cmpl_list);
+                               if (ret)
+                                       return ret;
+
+                               break;
+                       case MEI_READ:
+                               /* send flow control message */
+                               ret = _mei_irq_thread_read(dev, slots,
+                                                   cb_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,
+                                                    cb_pos, cl, cmpl_list);
+                               if (ret)
+                                       return ret;
+
+                               break;
+
+                       default:
+                               BUG();
+                       }
+
+               }
+       }
+       /* complete  write list CB */
+       if (!dev->write_list.status &&
+           !list_empty(&dev->write_list.mei_cb.cb_list)) {
+               dev_dbg(&dev->pdev->dev, "complete write list cb.\n");
+               list_for_each_entry_safe(cb_pos, cb_next,
+                               &dev->write_list.mei_cb.cb_list, cb_list) {
+                       cl = (struct mei_cl *)cb_pos->file_private;
+
+                       if (cl) {
+                               if (cl != &dev->iamthif_cl) {
+                                       if (!mei_flow_ctrl_creds(dev,
+                                               cl)) {
+                                               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,
+                                                           cb_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)) {
+                                               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,
+                                                               cb_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_wd_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, wd_work.work);
+
+
+       mutex_lock(&dev->device_lock);
+       if (dev->mei_state != MEI_ENABLED) {
+               if (dev->mei_state == MEI_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->wd_cl.state != MEI_FILE_CONNECTED)
+               goto out;
+
+       /* Watchdog */
+       if (dev->wd_due_counter && !dev->wd_bypass) {
+               if (--dev->wd_due_counter == 0) {
+                       if (dev->mei_host_buffer_is_empty &&
+                           mei_flow_ctrl_creds(dev, &dev->wd_cl) > 0) {
+                               dev->mei_host_buffer_is_empty = 0;
+                               dev_dbg(&dev->pdev->dev, "send watchdog.\n");
+
+                               if (mei_wd_send(dev))
+                                       dev_dbg(&dev->pdev->dev, "wd send failed.\n");
+                               else
+                                       if (mei_flow_ctrl_reduce(dev, &dev->wd_cl))
+                                               goto out;
+
+                               if (dev->wd_timeout)
+                                       dev->wd_due_counter = 2;
+                               else
+                                       dev->wd_due_counter = 0;
+
+                       } else
+                               dev->wd_pending = 1;
+
+               }
+       }
+       if (dev->iamthif_stall_timer) {
+               if (--dev->iamthif_stall_timer == 0) {
+                       dev_dbg(&dev->pdev->dev, "reseting 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 = 0;
+                       dev->iamthif_ioctl = 1;
+                       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;
+                       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;
+
+                       if (!list_empty(amthi_complete_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;
+                       run_next_iamthif_cmd(dev);
+
+               }
+       }
+out:
+        schedule_delayed_work(&dev->wd_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_initialize_list(&complete_list, dev);
+       dev->host_hw_state = mei_hcsr_read(dev);
+       dev->me_hw_state = mei_mecsr_read(dev);
+
+       /* check if ME wants a reset */
+       if ((dev->me_hw_state & ME_RDY_HRA) == 0 &&
+           dev->mei_state != MEI_RESETING &&
+           dev->mei_state != MEI_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->mei_state = MEI_INIT_CLIENTS;
+                       dev_dbg(&dev->pdev->dev, "link is established start sending messages.\n");
+                       /* link is established
+                        * start sending messages.
+                        */
+                       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 avalable 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_host_buffer_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 (complete_list.status || 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;
+}