view src/g23m-aci/gdd_dio/gdd_dio_queue.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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/*
+-----------------------------------------------------------------------------
|  File     : gdd_dio_queue.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  : Implements the queue functions for the DIO buffer FIFO
+-----------------------------------------------------------------------------
*/


#define ENTITY_GDD_DIO

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

#include "typedefs.h"   /* to get Condat data types */
#include "vsi.h"        /* to get a lot of macros */

#include <string.h>  /* for memset */

#include "gdd_dio_queue.h"

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

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

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

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


GLOBAL void gdd_dio_queue_clear(T_GDD_BUF_QUEUE *queue)
{
  queue->next_in = 0;
  queue->next_out = 0;
  memset(queue->elems, 0, sizeof(T_dio_buffer *) * GDD_MAX_DIO_BUF);
}


BOOL gdd_dio_queue_is_empty(const T_GDD_BUF_QUEUE *queue)
{
  return (queue->next_in == queue->next_out) &&
         (0 == queue->elems[queue->next_out]);
}


GLOBAL BOOL gdd_dio_queue_is_full(const T_GDD_BUF_QUEUE *queue)
{
  return (queue->next_in == queue->next_out) && 
          !(0 == queue->elems[queue->next_out]);
}


GLOBAL BOOL gdd_dio_dequeue(T_GDD_BUF_QUEUE *queue, T_dio_buffer **elem)
{
  if(gdd_dio_queue_is_empty(queue))
  {
    return FALSE;
  }
  else
  {
    (*elem) = queue->elems[queue->next_out];
    queue->elems[queue->next_out] = 0;
    ++(queue->next_out);
    if(queue->next_out EQ GDD_MAX_DIO_BUF)
      queue->next_out = 0;
    return TRUE;
  }
}

GLOBAL BOOL gdd_dio_queue_peek_next_for_dequeue
(const T_GDD_BUF_QUEUE *queue, /*out*/T_dio_buffer **elem)
{
  if(gdd_dio_queue_is_empty(queue))
  {
    return FALSE;
  }
  else
  {
    (*elem) = queue->elems[queue->next_out];
    return TRUE;
  }
}

GLOBAL BOOL gdd_dio_enqueue(T_dio_buffer *elem, T_GDD_BUF_QUEUE *queue, /*out*/U16 *pos)
{
  if(gdd_dio_queue_is_full(queue))
  {
    return FALSE;
  }
  else
  {
    queue->elems[queue->next_in] = elem;
    (*pos) = queue->next_in;
    ++(queue->next_in);
    if(queue->next_in EQ GDD_MAX_DIO_BUF)
      queue->next_in = 0;
    return TRUE;
  }
}


GLOBAL void gdd_dio_queue_peek(const T_GDD_BUF_QUEUE *queue, U16 pos, /*out*/T_dio_buffer **elem)
{
  (*elem) = queue->elems[pos];
}