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view src/g23m-gprs/cci/cci_gea_start.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 :  
|  Modul   :  cci_gea_start.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 module implements local functions for service FBS of
|             entity CCI.
+----------------------------------------------------------------------------- 
*/ 

#define CCI_GEA_START_C

#ifndef CCI_THREAD
  #define ENTITY_LLC
#else
  #define ENTITY_CCI
#endif


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

#include "typedefs.h"   /* to get Condat data types */
#include "vsi.h"        /* to get a lot of macros */
#include "macdef.h"
#include "gprs.h"
#include "gsm.h"        /* to get a lot of macros */
#include "cnf_llc.h"    /* to get cnf-definitions */
#include "mon_llc.h"    /* to get mon-definitions */
#include "prim.h"       /* to get the definitions of used SAP and directions */
#include "cci.h"        /* to get the global entity definitions */
#ifndef CCI_THREAD
#include "llc.h"        /* to get the global entity definitions */
#endif

#ifndef _SIMULATION_
#include "config/chipset.cfg"
#endif /* ifdef SIMULATION */


/*==== CONST ================================================================*/

/*==== LOCAL VARS ===========================================================*/

/*==== PRIVATE FUNCTIONS ====================================================*/

/*==== PUBLIC FUNCTIONS =====================================================*/


/*
+------------------------------------------------------------------------------
| Function    : gea_start
+------------------------------------------------------------------------------
| Description : The function  .... 
|
| Parameters  : void
|
+------------------------------------------------------------------------------
*/


/* GEA work-around only affects Calypso+ chipset. */
  #ifndef CCI_FLASH_ROM
    /* Assembly routine gea_start() should be executed from the Internal RAM */
    void gea_start(void){
#if (CHIPSET == 12) || (CHIPSET == 14)
      /* Enable Timer1 clock */
      *(volatile USHORT *) 0xfffe3800 |= 0x0020; 

      /* Save into the stack ARM registers r0 to r4 */
      asm(" push {r0-r4}");

      /* Load in r0 READ_TIMER1 address */
      asm(" ldr r0, READ_TIMER1_ADDR");

      /* Set bit START in GEA_CNTL register */
      asm(" ldr r1, GEA_CNTL_ADDR");
      asm(" mov r4,#4");
      asm(" ldrh r2, [r1]");
      asm(" orr r2,r4");
      asm(" strh r2,[r1]");

      /* Load Timer1 in r3 in order to prevent DMA access on strobe0 during the
         GEA clock switch. This reading of Timer1 generates around 13 cycles of
         MCU clock activity on strobe1 and so guaranties that strobe0 will be
         quiet during that time. */
      asm(" ldrh r3,[r0]");

      /* Restore ARM registers r0 to r4 from the stack */
      asm(" pop {r0-r4}");

      /*  Branch to end of the function, to avoid that the 2 following constant 
          definitions are mistaken with code instructions. */
      asm(" br    $gea_end_func");

      /* Must be defined inside the function body, else depending on the compiler 
         version, they are not inserted in the right section */
    asm("READ_TIMER1_ADDR .long 0xFFFE3804");
    asm("GEA_CNTL_ADDR  .long 0xffffc000");

      asm("$gea_end_func:");      
    }
#else
    }    
#endif /*(CHIPSET == 12)*/

  #endif /* CCI_FLASH_ROM */