view src/g23m-gsm/dl/dl_dcch3.c @ 220:0ed36de51973

ABB semaphore protection overhaul The ABB semaphone protection logic that came with TCS211 from TI was broken in several ways: * Some semaphore-protected functions were called from Application_Initialize() context. NU_Obtain_Semaphore() called with NU_SUSPEND fails with NU_INVALID_SUSPEND in this context, but the return value wasn't checked, and NU_Release_Semaphore() would be called unconditionally at the end. The latter call would increment the semaphore count past 1, making the semaphore no longer binary and thus no longer effective for resource protection. The fix is to check the return value from NU_Obtain_Semaphore() and skip the NU_Release_Semaphore() call if the semaphore wasn't properly obtained. * Some SPI hardware manipulation was being done before entering the semaphore- protected critical section. The fix is to reorder the code: first obtain the semaphore, then do everything else. * In the corner case of L1/DSP recovery, l1_abb_power_on() would call some non-semaphore-protected ABB & SPI init functions. The fix is to skip those calls in the case of recovery. * A few additional corner cases existed, all of which are fixed by making ABB semaphore protection 100% consistent for all ABB functions and code paths. There is still one remaining problem of priority inversion: suppose a low- priority task calls an ABB function, and some medium-priority task just happens to preempt right in the middle of that semaphore-protected ABB operation. Then the high-priority SPI task is locked out for a non-deterministic time until that medium-priority task finishes its work and goes back to sleep. This priority inversion problem remains outstanding for now.
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 26 Apr 2021 20:55:25 +0000
parents fa8dc04885d8
children
line wrap: on
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/*
+-----------------------------------------------------------------------------
|  Project :  GSM-PS
|  Modul   :  DL_DCCH3
+-----------------------------------------------------------------------------
|  Copyright 2002 Texas Instruments Berlin, AG
|                 All rights reserved.
|
|                 This file is confidential and a trade secret of Texas
|                 Instruments Berlin, AG
|                 The receipt of or possession of this file does not convey
|                 any rights to reproduce or disclose its contents or to
|                 manufacture, use, or sell anything it may describe, in
|                 whole, or in part, without the specific written consent of
|                 Texas Instruments Berlin, AG.
+-----------------------------------------------------------------------------
|  Purpose :  This Modul defines the functions for the slow
|             dedicated control channel (SAPI 3) of the component DL
+-----------------------------------------------------------------------------
*/

#ifndef DL_DCCH3_C
#define DL_DCCH3_C

#define ENTITY_DL

/*==== INCLUDES ===================================================*/

#include "typedefs.h"
#include <string.h>
#include "pconst.cdg"
#include "vsi.h"
#include "custom.h"
#include "gsm.h"
#include "mon_dl.h"
#include "prim.h"
#include "pei.h"
#include "tok.h"
#include "ccdapi.h"
#include "dl.h"
#include "dl_trc.h"


/*==== EXPORT =====================================================*/

/*==== PRIVAT =====================================================*/

/*==== VARIABLES ==================================================*/

/*==== FUNCTIONS ==================================================*/
/*
+--------------------------------------------------------------------+
| PROJECT : GSM-PS (6147)       MODULE  : DL_DCCH3                   |
| STATE   : code                ROUTINE : dcch3_init_dl_data         |
+--------------------------------------------------------------------+

  PURPOSE : Initialisation of SDCCH data (SAPI 3) for an instance.

*/

GLOBAL void dcch3_init_dl_data (void)
{
  GET_INSTANCE_DATA;
  T_CCH *pcch = &dl_data->cch[C_DCCH3];

  TRACE_FUNCTION ("dcch3_init_dl_data()");

  memset (pcch, 0, sizeof (T_CCH));
  com_clear_queue (PS_SAPI_3);

  if (dl_data->dcch3_in_msg)
  {
    COM_FREE_POINTER (dl_data->dcch3_in_msg);
    dl_data->dcch3_in_msg = NULL;
  }

  dl_data->dcch3_disc_request  = FALSE;
  set_channel_state(C_DCCH3, STATE_DISABLED);
}

/*
+--------------------------------------------------------------------+
| PROJECT : GSM-PS (6147)       MODULE  : DL_DCCH3                   |
| STATE   : code                ROUTINE : dcch3_enable               |
+--------------------------------------------------------------------+

  PURPOSE : Enabling SAPI 3 connections.

*/

GLOBAL void dcch3_enable (UBYTE ch_type)
{
  GET_INSTANCE_DATA;
  TRACE_FUNCTION ("dcch3_enable()");

  switch (dl_data->state[C_DCCH3])
  {
    case STATE_DISABLED:
      set_channel_state (C_DCCH3, STATE_IDLE_DL);
      dl_data->cch[C_DCCH3].ch_type = ch_type;
      break;
    default:
      break;
  }
}

/*
+--------------------------------------------------------------------+
| PROJECT : GSM-PS (6147)       MODULE  : DL_DCCH3                   |
| STATE   : code                ROUTINE : dcch3_establish_req       |
+--------------------------------------------------------------------+

  PURPOSE : Establish Request for SDCCH (SAPI 3).

*/

GLOBAL void dcch3_establish_req (T_DL_ESTABLISH_REQ * est_req)
{
  GET_INSTANCE_DATA;
  TRACE_FUNCTION ("dcch3_establish_req()");

  DL_OFFLINE_TRACE (TRACE_DL_EVENT, C_DCCH3, est_req->ch_type, "est req");


  switch (dl_data->state[C_DCCH3])
  {
    case STATE_IDLE_DL:
    case STATE_DISABLED:
    case STATE_MULTIPLE_FRAME_ESTABLISHED:
    case STATE_TIMER_RECOVERY:
      {
        T_CCH *pcch = &dl_data->cch[C_DCCH3];

        pcch->ch_type = est_req->ch_type;

        dl_data->dcch3_disc_request  = FALSE;
        dl_data->dcch3_unserved = com_queue_awaiting_transmission (PS_SAPI_3) ?
                                  DL_UNSERVED : DL_ALL_DONE;

        com_clear_queue (PS_SAPI_3);
        pcch->vtx       = SABM_CMD;
        pcch->time_flag = TRUE;
        pcch->rc        = 0;
        set_channel_state (C_DCCH3, STATE_AWAITING_ESTABLISHMENT);
        TRACE_EVENT_WIN_P5 ("EST_REQ: %s SAPI=%u vtx=%s (%s#%u)", CH_TYPE_NAME[pcch->ch_type],
                                            est_req->sapi, VTX_NAME[pcch->vtx],
                                            __FILE10__, __LINE__);
      }

      break;
    default:
      break;
  }
  COM_FREE_POINTER (est_req);
}

/*
+--------------------------------------------------------------------+
| PROJECT : GSM-PS (6147)       MODULE  : DL_SDCCH                   |
| STATE   : code                ROUTINE : sdcch3_release_req         |
+--------------------------------------------------------------------+

  PURPOSE : Release Request for SDCCH (SAPI 3).

*/

GLOBAL BOOL dcch3_release_req (T_DL_RELEASE_REQ * release_req)
{
  GET_INSTANCE_DATA;
  BOOL bFree = TRUE;

  TRACE_FUNCTION ("dcch3_release_req()");

  if (release_req->mode EQ DL_LOCAL_END_RELEASE)
  {
    DL_OFFLINE_TRACE (TRACE_DL_EVENT, C_DCCH3, release_req->ch_type, "local end release req");
    bFree = FALSE;
  }
  else
  {
    DL_OFFLINE_TRACE (TRACE_DL_EVENT, C_DCCH3, release_req->ch_type, "normal release req");
    dl_data->cch[C_DCCH3].ch_type = release_req->ch_type;
    switch (dl_data->state[C_DCCH3])
    {
      default:
        bFree = FALSE;
        break;

      case STATE_AWAITING_ESTABLISHMENT:
      case STATE_MULTIPLE_FRAME_ESTABLISHED:
      case STATE_TIMER_RECOVERY:
        if (!dl_data->dcch3_disc_request AND (dl_data->cch[C_DCCH3].vtx EQ RR_CMD))
        {
          dl_data->dcch3_disc_request = TRUE;
        }
        else
        {
          com_prepare_DISC (C_DCCH3, release_req->sapi);
        }
        break;

      case STATE_AWAITING_RELEASE:
        dl_data->cch[C_DCCH3].T200_counter = 0;
        break;
    }
  }

  if (bFree EQ FALSE)
  {
    PREUSE (release_req, release_cnf, DL_RELEASE_CNF);
    release_cnf->indication =
      com_queue_awaiting_transmission (PS_SAPI_3) ? DL_UNSERVED : DL_ALL_DONE;
    PSENDX (RR, release_cnf);
    dcch3_init_dl_data ();
  }

  return bFree;
}


/*
+--------------------------------------------------------------------+
| PROJECT : GSM-PS (6147)       MODULE  : DL_DCCH3                   |
| STATE   : code                ROUTINE : dcch3_mdl_release_req     |
+--------------------------------------------------------------------+

  PURPOSE : Release Request from Mobility Management for SDCCH (SAPI 3).

*/

GLOBAL void dcch3_mdl_release_req (void)
{
  GET_INSTANCE_DATA;
  TRACE_FUNCTION ("dcch3_mdl_release_req()");

  DL_OFFLINE_TRACE (TRACE_DL_EVENT, C_DCCH3, dl_data->cch[C_DCCH3].ch_type, "mdl rel req");

  switch (dl_data->state[C_DCCH3])
  {
    case STATE_AWAITING_ESTABLISHMENT:
    case STATE_TIMER_RECOVERY:
    case STATE_AWAITING_RELEASE:
      drr_dl_release_cnf (dl_data->cch[C_DCCH3].ch_type, PS_SAPI_3, TRUE);
      break;

    case STATE_MULTIPLE_FRAME_ESTABLISHED:
      drr_dl_release_ind (dl_data->cch[C_DCCH3].ch_type, PS_SAPI_3, NOT_PRESENT_8BIT, TRUE);
      break;

    default:
      break;
  }
}

/*
+--------------------------------------------------------------------+
| PROJECT : GSM-PS (6147)       MODULE  : DL_DCCH3                   |
| STATE   : code                ROUTINE : dcch3_data_req            |
+--------------------------------------------------------------------+

  PURPOSE : Data Request on SDCCH (SAPI 3).

*/

GLOBAL void dcch3_data_req (T_DL_DATA_REQ * data_req)
{
  GET_INSTANCE_DATA;
  TRACE_FUNCTION ("dcch3_data_req()");

  switch (dl_data->state[C_DCCH3])
  {
    case STATE_MULTIPLE_FRAME_ESTABLISHED:
    case STATE_TIMER_RECOVERY:
      com_store_queue (PS_SAPI_3, data_req);
      break;

    default:
      COM_FREE_POINTER (data_req);
      break;
  }
}

/*
+--------------------------------------------------------------------+
| PROJECT : GSM-PS (6147)       MODULE  : DL_SDCCH                   |
| STATE   : code                ROUTINE : dcch3_check_disc           |
+--------------------------------------------------------------------+

  PURPOSE : DISC command frame on DCCH3.

*/

GLOBAL int dcch3_check_disc (int send)
{
  GET_INSTANCE_DATA;
  TRACE_FUNCTION ("dcch3_check_disc()");

  if (dl_data->dcch3_disc_request AND !(dl_data->cch[C_DCCH3].vtx EQ RR_CMD))
  {
    com_prepare_DISC (C_DCCH3, PS_SAPI_3);
    return uplink_awaiting_release (C_DCCH3, PS_SAPI_3);
  }
  else
    return send;
}
#endif /* DL_DCCH3_C */