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view src/g23m-gprs/cl/cl_nwrl.c @ 220:0ed36de51973

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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 :  GPRS (8441)
|  Module  :  CL
|  File    :  cl_nwrl.c
+----------------------------------------------------------------------------- 
|  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 file implements common library functions related to the
|             network release(in this case, SGSN release) for all entities of 
|             the GPRS protocol stack
+----------------------------------------------------------------------------- 
*/ 

#ifndef CL_NWRL_C
#define CL_NWRL_C
#endif

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

#include "typedefs.h"    /* to get Condat data types */
#include "vsi.h"
#include "p_cl.val"  /* to get the type of sgsn_rel*/
#include "p_8010_152_ps_include.h" /*to get T_PS_qos_rXX*/
#include "cl_inline.h"

LOCAL U8 sgsn_release;

/*
+------------------------------------------------------------------------------
| Function    : cl_nwrl_set_sgsn_release() 
+------------------------------------------------------------------------------
| Description : The function cl_nwrl_set_sgsn_release() sets the status of SGSN 
|               release as received in SI13, PSI1 and PSI13 messages. This is 
|               called by GRR during initialization after Power On, when 
|               processing SI13, PSI1 and PSI13
|
| Parameters  : U8 sgsn_rel
|
+------------------------------------------------------------------------------
*/

GLOBAL void cl_nwrl_set_sgsn_release(U8 sgsn_rel)
{
  TRACE_FUNCTION( "cl_nwrl_set_sgsn_release()" );
  sgsn_release = sgsn_rel;
}


/*
+------------------------------------------------------------------------------
| Function    : cl_nwrl_get_sgsn_release()
+------------------------------------------------------------------------------
| Description : The function cl_nwrl_get_sgsn_release() gets the status of SGSN
|               release. This is called up by entities such as GMM, SM that need
|               the SGSN release. It is advised to call this function only after
|               a cell re-selection as the SGSN release value is invalid during
|               cell re-selection.
|
| Parameters  : Nil
|
+------------------------------------------------------------------------------
*/

GLOBAL U8 cl_nwrl_get_sgsn_release()
{
  TRACE_FUNCTION( "cl_nwrl_get_sgsn_release()" );
  return sgsn_release;
}