view src/cs/services/tty/tty_api.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 4e78acac3d88
children
line wrap: on
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/**
 * @file	tut_api.c
 *
 * API for TTY SWE.
 *
 * @author	Frederic Turgis (f-turgis@ti.com) & Gerard Cauvy (g-cauvy@ti.com)
 * @version 0.1
 */

/*
 * History:
 *
 * 	Date       	Modification
 *  ------------------------------------
 *  01/27/2003	Create
 *
 * (C) Copyright 2003 by Texas Instruments Incorporated, All Rights Reserved
 */

#ifndef _WINDOWS
  #include "config/l1sw.cfg"
#endif

#include "tty/tty_i.h"

#include "tty/tty_api.h"
#include "audio/audio_structs_i.h"
#include "audio/audio_const_i.h"

/* External declaration */
extern T_AUDIO_ENV_CTRL_BLK* p_audio_gbl_var;

/********************************************************************************/
/*                                                                              */
/*    Function Name:   audio_tty_set_config                                     */
/*                                                                              */
/*    Purpose:  This function is called to configure TTY. Currently, only       */
/*              supports start and stop                                         */
/*                                                                              */
/*    Input Parameters:                                                         */
/*        TTY configuration                                                     */
/*        Return path.                                                          */
/*                                                                              */
/*    Output Parameters:                                                        */
/*         Validation of the parameters.                                        */
/*                                                                              */
/*    Note:                                                                     */
/*        None.                                                                 */
/*                                                                              */
/*    Revision History:                                                         */
/*        None.                                                                 */
/*                                                                              */
/********************************************************************************/
T_AUDIO_RET audio_tty_set_config (T_AUDIO_TTY_CONFIG_PARAMETER *parameter, T_RV_RETURN *return_path)
{
  #if (L1_GTT == 1)
    /* Declare local variables. */
    T_RVF_MB_STATUS   mb_status = RVF_GREEN;
    T_RV_HDR *p_msg = NULL;

    /************************ audio_tty_set_config function begins ******************/
    if (p_audio_gbl_var == NULL )
    {
      TTY_SEND_TRACE("TTY: Error Audio SWE not started ",RV_TRACE_LEVEL_ERROR);
      return(AUDIO_ERROR);
    }

    /* If bad parameters, then report an error and abort.*/
    if ( (parameter->Mode != TTY_STOP)&&
         (parameter->Mode != TTY_EXT_START))
    {
      TTY_SEND_TRACE("TTY: Error bad parameters ",RV_TRACE_LEVEL_ERROR);
      return (AUDIO_ERROR);
    }

    switch (parameter->Mode)
    {
      case TTY_EXT_START:
      {
        /* allocate the memory for the message to send */
        mb_status = rvf_get_buf (p_audio_gbl_var->mb_external,
                                 sizeof (T_TTY_START),
                                 (T_RVF_BUFFER **) (&p_msg));
      }
      break;
      case TTY_STOP:
      {
        /* allocate the memory for the message to send */
        mb_status = rvf_get_buf (p_audio_gbl_var->mb_external,
                                 sizeof (T_TTY_STOP),
                                 (T_RVF_BUFFER **) (&p_msg));
      }
      break;
    }

    /* If insufficient resources, then report a memory error and abort. */
    if (mb_status == RVF_YELLOW)
    {
      /* deallocate the memory */
      rvf_free_buf((T_RVF_BUFFER *)p_msg);
      TTY_SEND_TRACE("TTY: Not Enough Memory (Yellow!) ",RV_TRACE_LEVEL_ERROR);
      return (AUDIO_ERROR);
    }
    else
    if (mb_status == RVF_RED)
    {
      TTY_SEND_TRACE("TTY: Not Enough Memory (Red!) ",RV_TRACE_LEVEL_ERROR);
      return (AUDIO_ERROR);
    }

    /* fill the message id + parameters */
    switch (parameter->Mode)
    {
      case TTY_EXT_START:
        p_msg->msg_id = TTY_START_REQ;

        if (return_path->callback_func == NULL)
        {
          ((T_TTY_START *)p_msg)->return_path.addr_id = return_path->addr_id;
          ((T_TTY_START *)p_msg)->return_path.callback_func = NULL;
        }
        else
        {
          ((T_TTY_START *)p_msg)->return_path.callback_func = return_path->callback_func;
        }
      break;
      case TTY_STOP:
        p_msg->msg_id = TTY_STOP_REQ;
      break;
    }

    /* fill the address source id */
    p_msg->src_addr_id = rvf_get_taskid();
    p_msg->dest_addr_id = p_audio_gbl_var->addrId;

    /* send the messsage to the audio entity */
    rvf_send_msg (p_audio_gbl_var->addrId, p_msg);

    return (AUDIO_OK);

  #else // L1_GTT

    TTY_SEND_TRACE("TTY API not available ", RV_TRACE_LEVEL_ERROR);
    return (AUDIO_ERROR);

  #endif
}