/*
 * Copyright (c) 2012-2015,2017 The Linux Foundation. All rights reserved.
 *
 * Previously licensed under the ISC license by Qualcomm Atheros, Inc.
 *
 *
 * Permission to use, copy, modify, and/or distribute this software for
 * any purpose with or without fee is hereby granted, provided that the
 * above copyright notice and this permission notice appear in all
 * copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
 * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * This file was originally distributed by Qualcomm Atheros, Inc.
 * under proprietary terms before Copyright ownership was assigned
 * to the Linux Foundation.
 */

/*===========================================================================

                       W L A N _ Q C T _ C T S . C

  OVERVIEW:

  This software unit holds the implementation of the WLAN Control Transport
  Service Layer.

  The functions externalized by this module are to be called by the DAL Core
  that wishes to use a platform agnostic API to communicate with the WLAN SS.

  DEPENDENCIES:

  Are listed for each API below.


===========================================================================*/

/*===========================================================================

                      EDIT HISTORY FOR FILE


  This section contains comments describing changes made to the module.
  Notice that changes are listed in reverse chronological order.


  $Header$$DateTime$$Author$


  when          who    what, where, why
  ----------    ---    --------------------------------------------------------
  2011-02-28    jtj    Linux/Android implementation which utilizes SMD
  2010-08-09    mss    Created module

===========================================================================*/


/*===========================================================================

                          INCLUDE FILES FOR MODULE

===========================================================================*/

/*----------------------------------------------------------------------------
 * Include Files
 * -------------------------------------------------------------------------*/
#include "wlan_qct_wdi_cts.h"
#include "wlan_qct_pal_msg.h"
#include "wlan_qct_pal_api.h"
#include "wlan_qct_pal_trace.h"
#include "wlan_qct_os_list.h"
#include "wlan_qct_wdi.h"
#include "wlan_qct_wdi_i.h"
#ifdef CONFIG_ANDROID
#ifdef EXISTS_MSM_SMD
#include <mach/msm_smd.h>
#else
#include <soc/qcom/smd.h>
#endif
#include <linux/delay.h>
#else
#include "msm_smd.h"
#endif

/* Global context for CTS handle, it is required to keep this 
 * transport open during SSR shutdown */
static WCTS_HandleType gwctsHandle;
/*----------------------------------------------------------------------------
 * Preprocessor Definitions and Constants
 * -------------------------------------------------------------------------*/

/* Magic value to validate a WCTS CB (value is little endian ASCII: WCTS */
#define WCTS_CB_MAGIC     0x53544357

/* time to wait for SMD channel to open (in msecs) */
#define WCTS_SMD_OPEN_TIMEOUT 5000

/* time to wait for SMD channel to close (in msecs) */
#define WCTS_SMD_CLOSE_TIMEOUT 5000

/* Global Variable for WDI SMD stats */
static struct WdiSmdStats gWdiSmdStats;
/*----------------------------------------------------------------------------
 * Type Declarations
 * -------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------
   WCTS_StateType
 ---------------------------------------------------------------------------*/
typedef enum
{
   WCTS_STATE_CLOSED,       /* Closed */
   WCTS_STATE_OPEN_PENDING, /* Waiting for the OPEN event from SMD */
   WCTS_STATE_OPEN,         /* Open event received from SMD */
   WCTS_STATE_DEFERRED,     /* Write pending, SMD chennel is full */
   WCTS_STATE_REM_CLOSED,   /* Remote end closed the SMD channel */
   WCTS_STATE_MAX
} WCTS_StateType;

/*---------------------------------------------------------------------------
   Control Transport Control Block Type
 ---------------------------------------------------------------------------*/
typedef struct
{
   WCTS_NotifyCBType      wctsNotifyCB;
   void*                  wctsNotifyCBData;
   WCTS_RxMsgCBType       wctsRxMsgCB;
   void*                  wctsRxMsgCBData;
   WCTS_StateType         wctsState;
   vos_spin_lock_t        wctsStateLock;
   smd_channel_t*         wctsChannel;
   wpt_list               wctsPendingQueue;
   wpt_uint32             wctsMagic;
   wpt_msg                wctsOpenMsg;
   wpt_msg                wctsDataMsg;
   wpt_event              wctsEvent;
} WCTS_ControlBlockType;

/*---------------------------------------------------------------------------
   WDI CTS Buffer Type
 ---------------------------------------------------------------------------*/
typedef struct
{
   /*Node for linking pending buffers into a linked list */
   wpt_list_node          node;

   /*Buffer associated with the request */
   void*                  pBuffer;

   /*Buffer Size*/
   int                    bufferSize;

} WCTS_BufferType;

/*----------------------------------------------------------------------------
 * Global Data Definitions
 * -------------------------------------------------------------------------*/

/*----------------------------------------------------------------------------
 * Static Variable Definitions
 * -------------------------------------------------------------------------*/

/*----------------------------------------------------------------------------
 * Static Function Declarations and Definitions
 * -------------------------------------------------------------------------*/


/**
 @brief    Callback function for serializing WCTS Open
           processing in the control context
 @param

    pMsg - pointer to the message

 @see
 @return void
*/
static void
WCTS_PALOpenCallback
(
   wpt_msg *pMsg
)
{
   WCTS_ControlBlockType*        pWCTSCb;
   /*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

   /* extract our context from the message */
   pWCTSCb = pMsg->pContext;

   /*--------------------------------------------------------------------
     Sanity check
     --------------------------------------------------------------------*/
   if ((NULL == pWCTSCb) || (WCTS_CB_MAGIC != pWCTSCb->wctsMagic)) {
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "WCTS_PALOpenCallback: Invalid parameters received.");
      return;
   }

   if (WCTS_STATE_OPEN_PENDING != pWCTSCb->wctsState) {
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "WCTS_PALOpenCallback: Invoke from invalid state %d.",
                 pWCTSCb->wctsState);
      return;
   }

   /* notified registered client that the channel is open */
   pWCTSCb->wctsState = WCTS_STATE_OPEN;
   pWCTSCb->wctsNotifyCB((WCTS_HandleType)pWCTSCb,
                        WCTS_EVENT_OPEN,
                        pWCTSCb->wctsNotifyCBData);

   /* signal event for WCTS_OpenTransport to proceed */
   wpalEventSet(&pWCTSCb->wctsEvent);

}/*WCTS_PALOpenCallback*/


/**
 @brief    Callback function for serializing WCTS Read
           processing in the control context

 @param    pWCTSCb  WCTS Control Block

 @see
 @return void
*/
static void
WCTS_PALReadCallback
(
   WCTS_ControlBlockType*  pWCTSCb
)
{
   void* buffer;
   int packet_size;
   int available;
   int bytes_read;

   /*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

   /*--------------------------------------------------------------------
     Sanity check
     --------------------------------------------------------------------*/
   if ((NULL == pWCTSCb) || (WCTS_CB_MAGIC != pWCTSCb->wctsMagic)) {
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "WCTS_PALReadCallback: Invalid parameter received.");
      return;
   }

   /* iterate until no more packets are available */
   while (1) {
      /* check the length of the next packet */
      packet_size = smd_cur_packet_size(pWCTSCb->wctsChannel);
      if (0 == packet_size) {
         /* No more data to be read */
         return;
      }

      /* Check how much of the data is available */
      available = smd_read_avail(pWCTSCb->wctsChannel);
      if (available < packet_size) {
         /* Entire packet not yet ready to be read --
            There will be another notification when it is ready */
         return;
      }

      buffer = wpalMemoryAllocate(packet_size);
      if (NULL ==  buffer) {
         WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                    "WCTS_PALReadCallback: Memory allocation failure");
         WPAL_ASSERT(0);
         return;
      }

      bytes_read = smd_read(pWCTSCb->wctsChannel,
                            buffer,
                            packet_size);

      if (bytes_read != packet_size) {
         /*Some problem, do not forward it to WDI.*/
         WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                    "WCTS_PALReadCallback: Failed to read data from SMD");
         wpalMemoryFree(buffer);
         WPAL_ASSERT(0);
         return;
      }

      /* forward the message to the registered handler */
      pWCTSCb->wctsRxMsgCB((WCTS_HandleType)pWCTSCb,
                           buffer,
                           packet_size,
                           pWCTSCb->wctsRxMsgCBData);

      /* Free the allocated buffer*/
      wpalMemoryZero(buffer, bytes_read);
      wpalMemoryFree(buffer);
   }

} /*WCTS_PALReadCallback*/


/**
 @brief    Callback function for serializing WCTS Write
           processing in the control context

 @param    pWCTSCb  WCTS Control Block

 @see
 @return void
*/
static void
WCTS_PALWriteCallback
(
   WCTS_ControlBlockType*  pWCTSCb
)
{
   wpt_list_node*      pNode;
   WCTS_BufferType*    pBufferQueue;
   void*               pBuffer;
   int                 len;
   int                 available;
   int                 written;

   /*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

   /*--------------------------------------------------------------------
     Sanity check
     --------------------------------------------------------------------*/
   if ((NULL == pWCTSCb) || (WCTS_CB_MAGIC != pWCTSCb->wctsMagic)) {
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "WCTS_PALWriteCallback: Invalid parameter received.");
      return;
   }

   /* if we are not deferred, then there are no pending packets */
   if (WCTS_STATE_DEFERRED != pWCTSCb->wctsState) {
      return;
   }

   /* Keep sending deferred messages as long as there is room in
      the channel.  Note that we initially peek at the head of the
      list to access the parameters for the next message; we don't
      actually remove the next message from the deferred list until
      we know the channel can handle it */
   while (eWLAN_PAL_STATUS_SUCCESS ==
          wpal_list_peek_front(&pWCTSCb->wctsPendingQueue, &pNode)) {
      pBufferQueue = container_of(pNode, WCTS_BufferType, node);
      pBuffer = pBufferQueue->pBuffer;
      len = pBufferQueue->bufferSize;

      available = smd_write_avail(pWCTSCb->wctsChannel);
      if (available < len) {
         /* channel has no room for the next packet so we are done */
         return;
      }

      /* there is room for the next message, so we can now remove
         it from the deferred message queue and send it */
      wpal_list_remove_front(&pWCTSCb->wctsPendingQueue, &pNode);

      /* note that pNode will be the same as when we peeked, so
         there is no need to update pBuffer or len */

      written = smd_write(pWCTSCb->wctsChannel, pBuffer, len);
      if (written != len) {
         /* Something went wrong */
         WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                    "WCTS_PALWriteCallback: channel write failure");

         /* we were unable to send the message that was at the head
            of the deferred list.  there is nothing else we can do
            other than drop it, so we will just fall through to the
            "success" processing.
            hopefully the client can recover from this since there is
            nothing else we can do here */
      }

      /* whether we had success or failure, reclaim all memory */
      wpalMemoryZero(pBuffer, len);
      wpalMemoryFree(pBuffer);
      wpalMemoryFree(pBufferQueue);

      /* we'll continue to iterate until the channel is full or all
         of the deferred messages have been sent */
   }

   /* if we've exited the loop, then we have drained the deferred queue.
      set the state to indicate we are no longer deferred, and turn off
      the remote read interrupt */
   pWCTSCb->wctsState = WCTS_STATE_OPEN;
   smd_disable_read_intr(pWCTSCb->wctsChannel);

} /*WCTS_PALWriteCallback*/


/**
 @brief    Callback function for serializing SMD DATA Event
           processing in the control context
 @param

    pMsg - pointer to the message

 @see
 @return void
*/
static void
WCTS_PALDataCallback
(
   wpt_msg *pMsg
)
{
   WCTS_ControlBlockType*        pWCTSCb;
   /*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

   /* extract our context from the message */
   pWCTSCb = pMsg->pContext;

   /* process any incoming messages */
   WCTS_PALReadCallback(pWCTSCb);

   /* send any deferred messages */
   WCTS_PALWriteCallback(pWCTSCb);

} /*WCTS_PALDataCallback*/

/**
 @brief    This helper function is used to clean up the pending 
           messages in the transport queue

 @param wctsHandlehandle:  transport handle

 @see
 @return   0 for success
*/
wpt_uint32
WCTS_ClearPendingQueue
(
   WCTS_HandleType      wctsHandle
)
{
   WCTS_ControlBlockType* pWCTSCb = (WCTS_ControlBlockType*) wctsHandle;
   wpt_list_node*      pNode = NULL;
   WCTS_BufferType*    pBufferQueue = NULL;
   void*               pBuffer = NULL;

   /*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

   if ((NULL == pWCTSCb) || (WCTS_CB_MAGIC != pWCTSCb->wctsMagic)) {
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "WCTS_ClearPendingQueue: Invalid parameters received.");
      return eWLAN_PAL_STATUS_E_INVAL;
   }

   /*Free the buffers in the pending queue.*/
   while (eWLAN_PAL_STATUS_SUCCESS ==
          wpal_list_remove_front(&pWCTSCb->wctsPendingQueue, &pNode)) {
      pBufferQueue = container_of(pNode, WCTS_BufferType, node);
      pBuffer = pBufferQueue->pBuffer;
      wpalMemoryFree(pBuffer);
      wpalMemoryFree(pBufferQueue);
   }
   return eWLAN_PAL_STATUS_SUCCESS;

}/*WCTS_ClearPendingQueue*/


/**
 * Notification callback when SMD needs to communicate asynchronously with
 * the client.
 *
 * This callback function may be called from interrupt context; clients must
 * not block or call any functions that block.
 *
 * @param[in] data   The user-supplied data provided to smd_named_open_on_edge()
 * @param[in] event  The event that occurred
 *
 * @return void
 */

static void
WCTS_NotifyCallback
(
   void            *data,
   unsigned        event
)
{
   wpt_msg                       *palMsg;
   WCTS_ControlBlockType*        pWCTSCb = (WCTS_ControlBlockType*) data;

   /*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

   /*--------------------------------------------------------------------
     Sanity check
     --------------------------------------------------------------------*/
   if (WCTS_CB_MAGIC != pWCTSCb->wctsMagic) {
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "%s: Received unexpected SMD event %u",
                 __func__, event);

      /* TODO_PRIMA what error recovery options do we have? */
      return;
   }

   /* Serialize processing in the control thread */
   switch (event) {
   case SMD_EVENT_OPEN:
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_INFO,
                 "%s: received SMD_EVENT_OPEN from SMD", __func__);
      /* If the prev state was 'remote closed' then it is a Riva 'restart',
       * subsystem restart re-init
       */
      if (WCTS_STATE_REM_CLOSED == pWCTSCb->wctsState)
      {
           WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_INFO,
                 "%s: received SMD_EVENT_OPEN in WCTS_STATE_REM_CLOSED state",
                 __func__);
           /* call subsystem restart re-init function */
           wpalDriverReInit();
           return;
      }
      gWdiSmdStats.smd_event_open++;
      palMsg = &pWCTSCb->wctsOpenMsg;
      break;

   case SMD_EVENT_DATA:
      if (WCTS_STATE_REM_CLOSED == pWCTSCb->wctsState)
      {
           WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "%s: received SMD data when the state is remote closed ",
                 __func__);
           /* we should not be getting any data now */
           return;
      }
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_INFO,
                 "%s: received SMD_EVENT_DATA from SMD", __func__);
      palMsg = &pWCTSCb->wctsDataMsg;
      gWdiSmdStats.smd_event_data++;
      break;

   case SMD_EVENT_CLOSE:
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_INFO,
                 "%s: received SMD_EVENT_CLOSE from SMD", __func__);
      /* SMD channel was closed from the remote side,
       * this would happen only when Riva crashed and SMD is
       * closing the channel on behalf of Riva */
      vos_spin_lock_acquire(&pWCTSCb->wctsStateLock);
      pWCTSCb->wctsState = WCTS_STATE_REM_CLOSED;
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_INFO,
                 "%s: received SMD_EVENT_CLOSE WLAN driver going down now",
                 __func__);
      vos_spin_lock_release(&pWCTSCb->wctsStateLock);

      /* subsystem restart: shutdown */
      wpalDriverShutdown();
      gWdiSmdStats.smd_event_close++;
      return;

   case SMD_EVENT_STATUS:
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_INFO,
                 "%s: received SMD_EVENT_STATUS from SMD", __func__);
      gWdiSmdStats.smd_event_status++;
      return;

   case SMD_EVENT_REOPEN_READY:
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_INFO,
                 "%s: received SMD_EVENT_REOPEN_READY from SMD", __func__);

      /* unlike other events which occur when our kernel threads are
         running, this one is received when the threads are closed and
         the rmmod thread is waiting.  so just unblock that thread */
      wpalEventSet(&pWCTSCb->wctsEvent);
      gWdiSmdStats.smd_event_reopen_ready++;
      return;

   default:
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "%s: Unexpected event %u received from SMD",
                 __func__, event);
      gWdiSmdStats.smd_event_err++;

      return;
   }

   /* serialize this event */
   wpalPostCtrlMsg(WDI_GET_PAL_CTX(), palMsg);

} /*WCTS_NotifyCallback*/


/*----------------------------------------------------------------------------
 * Externalized Function Definitions
 * -------------------------------------------------------------------------*/


/**
 @brief     This function is used by the DAL Core to initialize the Control
            Transport for processing. It must be called prior to calling any
            other APIs of the Control Transport.


 @param szName:   unique name for the channel that is to be opened
         uSize:   size of the channel that must be opened (should fit the
                  largest size of  packet that the Dal Core wishes to send)
         wctsCBs:  a list of callbacks that the CT needs to use to send
                  notification and messages back to DAL

 @see
 @return  A handle that must be used for further communication with the CTS.
         This is an opaque structure for the caller and it will be used in
         all communications to and from the CTS.

*/
WCTS_HandleType
WCTS_OpenTransport
(
   const wpt_uint8*         szName,
   wpt_uint32               uSize,
   WCTS_TransportCBsType*   wctsCBs
)
{
   WCTS_ControlBlockType*    pWCTSCb;
   wpt_status                status;
   int                       smdstatus;

   /*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -*/

   /*---------------------------------------------------------------------
     Sanity check
     ---------------------------------------------------------------------*/
   if ((NULL == wctsCBs) || (NULL == szName) ||
       (NULL == wctsCBs->wctsNotifyCB) || (NULL == wctsCBs->wctsRxMsgCB)) {
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "WCTS_OpenTransport: Invalid parameters received.");

      return NULL;
   }

   /* This open is coming after a SSR, we don't need to reopen SMD,
    * the SMD port was never closed during SSR*/
   if (gwctsHandle) {
       WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_INFO,
               "WCTS_OpenTransport port is already open");

       pWCTSCb = gwctsHandle;
       if (WCTS_CB_MAGIC != pWCTSCb->wctsMagic) {
           WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_FATAL,
                   "WCTS_OpenTransport: Invalid magic.");
           return NULL;
       }   
       pWCTSCb->wctsState = WCTS_STATE_OPEN;

       pWCTSCb->wctsNotifyCB((WCTS_HandleType)pWCTSCb,
               WCTS_EVENT_OPEN,
               pWCTSCb->wctsNotifyCBData);

       /* we initially don't want read interrupts
         (we only want them if we get into deferred write mode) */
       smd_disable_read_intr(pWCTSCb->wctsChannel);

       return (WCTS_HandleType)pWCTSCb;
   }

   /* allocate a ControlBlock to hold all context */
   pWCTSCb = wpalMemoryAllocate(sizeof(*pWCTSCb));
   if (NULL == pWCTSCb) {
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "WCTS_OpenTransport: Memory allocation failure.");
      return NULL;
   }

   /* make sure the control block is initialized.  in particular we need
      to make sure the embedded event and list structures are initialized
      to prevent "magic number" tests from being run against uninitialized
      values */
   wpalMemoryZero(pWCTSCb, sizeof(*pWCTSCb));

   /*Initialise the event*/
   wpalEventInit(&pWCTSCb->wctsEvent);

   /* save the user-supplied information */
   pWCTSCb->wctsNotifyCB       = wctsCBs->wctsNotifyCB;
   pWCTSCb->wctsNotifyCBData   = wctsCBs->wctsNotifyCBData;
   pWCTSCb->wctsRxMsgCB        = wctsCBs->wctsRxMsgCB;
   pWCTSCb->wctsRxMsgCBData    = wctsCBs->wctsRxMsgCBData;

   /* initialize the remaining fields */
   wpal_list_init(&pWCTSCb->wctsPendingQueue);
   pWCTSCb->wctsMagic   = WCTS_CB_MAGIC;
   vos_spin_lock_init(&pWCTSCb->wctsStateLock);
   pWCTSCb->wctsState   = WCTS_STATE_OPEN_PENDING;
   pWCTSCb->wctsChannel = NULL;

   /* since SMD will callback in interrupt context, we will used
    * canned messages to serialize the SMD events into a thread
    * context
    */
   pWCTSCb->wctsOpenMsg.callback = WCTS_PALOpenCallback;
   pWCTSCb->wctsOpenMsg.pContext = pWCTSCb;
   pWCTSCb->wctsOpenMsg.type= WPAL_MC_MSG_SMD_NOTIF_OPEN_SIG;

   pWCTSCb->wctsDataMsg.callback = WCTS_PALDataCallback;
   pWCTSCb->wctsDataMsg.pContext = pWCTSCb;
   pWCTSCb-> wctsDataMsg.type= WPAL_MC_MSG_SMD_NOTIF_DATA_SIG;

   /*---------------------------------------------------------------------
     Open the SMD channel
     ---------------------------------------------------------------------*/

   wpalEventReset(&pWCTSCb->wctsEvent);
   smdstatus = smd_named_open_on_edge(szName,
                                      SMD_APPS_WCNSS,
                                      &pWCTSCb->wctsChannel,
                                      pWCTSCb,
                                      WCTS_NotifyCallback);
   if (0 != smdstatus) {
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "%s: smd_named_open_on_edge failed with status %d",
                 __func__, smdstatus);
      goto fail;
   }

   /* wait for the channel to be fully opened before we proceed */
   status = wpalEventWait(&pWCTSCb->wctsEvent, WCTS_SMD_OPEN_TIMEOUT);
   if (eWLAN_PAL_STATUS_SUCCESS != status) {
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "%s: failed to receive SMD_EVENT_OPEN",
                 __func__);
      /* since we opened one end of the channel, close it */
      smdstatus = smd_close(pWCTSCb->wctsChannel);
      if (0 != smdstatus) {
         WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                    "%s: smd_close failed with status %d",
                    __func__, smdstatus);
      }
      goto fail;
   }

   /* we initially don't want read interrupts
      (we only want them if we get into deferred write mode) */
   smd_disable_read_intr(pWCTSCb->wctsChannel);

   /* we have successfully opened the SMD channel */
   gwctsHandle = pWCTSCb;
   return (WCTS_HandleType)pWCTSCb;

 fail:
   /* we were unable to open the SMD channel */
   pWCTSCb->wctsMagic = 0;
   wpalMemoryFree(pWCTSCb);
   return NULL;

}/*WCTS_OpenTransport*/


/**
 @brief    This function is used by the DAL Core to close the
           Control Transport when its services are no longer
           needed. Full close notification will be receive
           asynchronously on the notification callback
           registered on Open


 @param wctsHandlehandle:  received upon open

 @see
 @return   0 for success
*/
wpt_uint32
WCTS_CloseTransport
(
   WCTS_HandleType      wctsHandle
)
{
   WCTS_ControlBlockType* pWCTSCb = (WCTS_ControlBlockType*) wctsHandle;
   wpt_list_node*      pNode = NULL;
   WCTS_BufferType*    pBufferQueue = NULL;
   void*               pBuffer = NULL;
   wpt_status          status;
   int                 smdstatus;

   /*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

   if ((NULL == pWCTSCb) || (WCTS_CB_MAGIC != pWCTSCb->wctsMagic)) {
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "WCTS_CloseTransport: Invalid parameters received.");
      return eWLAN_PAL_STATUS_E_INVAL;
   }

   /*Free the buffers in the pending queue.*/
   while (eWLAN_PAL_STATUS_SUCCESS ==
          wpal_list_remove_front(&pWCTSCb->wctsPendingQueue, &pNode)) {
      pBufferQueue = container_of(pNode, WCTS_BufferType, node);
      pBuffer = pBufferQueue->pBuffer;
      wpalMemoryFree(pBuffer);
      wpalMemoryFree(pBufferQueue);
   }

   /* Reset the state */
   pWCTSCb->wctsState = WCTS_STATE_CLOSED;

   wpalEventReset(&pWCTSCb->wctsEvent);
   smdstatus = smd_close(pWCTSCb->wctsChannel);
   if (0 != smdstatus) {
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "%s: smd_close failed with status %d",
                 __func__, smdstatus);
      /* SMD did not successfully close the channel, therefore we
         won't receive an asynchronous close notification so don't
         bother to wait for an event that won't come */

   } else {
      /* close command was sent -- wait for the callback to complete */
      status = wpalEventWait(&pWCTSCb->wctsEvent, WCTS_SMD_CLOSE_TIMEOUT);
      if (eWLAN_PAL_STATUS_SUCCESS != status) {
         WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                    "%s: failed to receive SMD_EVENT_REOPEN_READY",
                    __func__);
      }

      /* During the close sequence we deregistered from SMD.  As part
         of deregistration SMD will call back into our driver with an
         event to let us know the channel is closed.  We need to
         insert a brief delay to allow that thread of execution to
         exit our module.  Otherwise our module may be unloaded while
         there is still code running within the address space, and
         that code will crash when the memory is unmapped  */
      msleep(50);
   }

   /* channel has (hopefully) been closed */
   pWCTSCb->wctsNotifyCB((WCTS_HandleType)pWCTSCb,
                         WCTS_EVENT_CLOSE,
                         pWCTSCb->wctsNotifyCBData);
   vos_spin_lock_destroy(&pWCTSCb->wctsStateLock);
   /* release the resource */
   pWCTSCb->wctsMagic = 0;
   wpalMemoryFree(pWCTSCb);
   gwctsHandle = NULL;

   return eWLAN_PAL_STATUS_SUCCESS;

}/*WCTS_CloseTransport*/


/**
 @brief    This function is used by the DAL Core to to send a
           message over to the WLAN sub-system.

           Once a buffer has been passed into the Send Message
 API, CT takes full ownership of it and it is responsible for
 freeing the associated resources. (This prevents a memcpy in
 case of a deferred write)

 The messages transported through the CT on both RX and TX are
 flat memory buffers that can be accessed and manipulated
 through standard memory functions.

 @param wctsHandlehandle:  received upon open
        pMsg:  the message to be sent
        uLen: the length of the message

 @see
 @return   0 for success
*/
wpt_uint32
WCTS_SendMessage
(
   WCTS_HandleType      wctsHandle,
   void*                pMsg,
   wpt_uint32           uLen
)
{
   WCTS_ControlBlockType*    pWCTSCb = (WCTS_ControlBlockType*) wctsHandle;
   WCTS_BufferType*          pBufferQueue;
   int                       len;
   int                       written = 0;
   int                       available;

   /*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

   /*--------------------------------------------------------------------
     Sanity check
     --------------------------------------------------------------------*/
   if ((NULL == pWCTSCb) || (WCTS_CB_MAGIC != pWCTSCb->wctsMagic) ||
       (NULL == pMsg) || (0 == uLen) || (0x7fffffff < uLen)) {
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "WCTS_SendMessage: Invalid parameters received.");
      WPAL_ASSERT(0);
      if (NULL != pMsg) {
         wpalMemoryFree(pMsg);
      }
      return eWLAN_PAL_STATUS_E_INVAL;
   }

   /* the SMD API uses int instead of uint, so change types here */
   len = (int)uLen;

   if (WCTS_STATE_OPEN == pWCTSCb->wctsState) {
      available = smd_write_avail(pWCTSCb->wctsChannel);
      if (available >= len) {
         written = smd_write(pWCTSCb->wctsChannel, pMsg, len);
      }
   } else if (WCTS_STATE_DEFERRED == pWCTSCb->wctsState) {
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_INFO,
                 "WCTS_SendMessage: FIFO space not available, the packets will be queued");
   } else {
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "WCTS_SendMessage: Channel in illegal state [%d].",
                 pWCTSCb->wctsState);
      /* force following logic to reclaim the buffer */
      written = -1;
   }

   if (-1 == written) {
      /*Something wrong*/
      WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                 "WCTS_SendMessage: Failed to send message over the bus.");
      wpalMemoryFree(pMsg);
      return eWLAN_PAL_STATUS_E_FAILURE;
   } else if (written == len) {
      /* Message sent! No deferred state, free the buffer*/
      wpalMemoryZero(pMsg, len);
      wpalMemoryFree(pMsg);
   } else {
      /* This much data cannot be written at this time,
         queue the rest of the data for later*/
      pBufferQueue = wpalMemoryAllocate(sizeof(WCTS_BufferType));
      if (NULL == pBufferQueue) {
         WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                    "WCTS_SendMessage: Cannot allocate memory for queuing the buffer");
         wpalMemoryFree(pMsg);
         WPAL_ASSERT(0);
         return eWLAN_PAL_STATUS_E_NOMEM;
      }

      pBufferQueue->bufferSize = len;
      pBufferQueue->pBuffer = pMsg;

      if (eWLAN_PAL_STATUS_E_FAILURE ==
             wpal_list_insert_back(&pWCTSCb->wctsPendingQueue,
                 &pBufferQueue->node))
      {
         WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
                    "pBufferQueue wpal_list_insert_back failed");
         wpalMemoryFree(pMsg);
         wpalMemoryFree(pBufferQueue);
         WPAL_ASSERT(0);
         return eWLAN_PAL_STATUS_E_NOMEM;
      }

      /* if we are not already in the deferred state, then transition
         to that state.  when we do so, we enable the remote read
         interrupt so that we'll be notified when messages are read
         from the remote end */
      vos_spin_lock_acquire(&pWCTSCb->wctsStateLock);
      if ((WCTS_STATE_DEFERRED != pWCTSCb->wctsState) &&
                        (WCTS_STATE_REM_CLOSED != pWCTSCb->wctsState)) {

         /* Mark the state as deferred.*/
         pWCTSCb->wctsState = WCTS_STATE_DEFERRED;

         smd_enable_read_intr(pWCTSCb->wctsChannel);
      }
      vos_spin_lock_release(&pWCTSCb->wctsStateLock);

      /*indicate to client that message was placed in deferred queue*/
      return eWLAN_PAL_STATUS_E_RESOURCES;
   }

   return eWLAN_PAL_STATUS_SUCCESS;

}/*WCTS_SendMessage*/

void WCTS_Dump_Smd_status(void)
{
    WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
              "Smd Read Stats: %d", gWdiSmdStats.smd_event_data);
    WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
              "Smd Open Stats: %d", gWdiSmdStats.smd_event_open);
    WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
              "Smd Close Stats: %d", gWdiSmdStats.smd_event_close);
    WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
              "Smd Status Stats: %d", gWdiSmdStats.smd_event_status);
    WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
              "Smd Reopen Stats: %d", gWdiSmdStats.smd_event_reopen_ready);
    WPAL_TRACE(eWLAN_MODULE_DAL_CTRL, eWLAN_PAL_TRACE_LEVEL_ERROR,
              "Smd Error Stats: %d", gWdiSmdStats.smd_event_err);
}