tmk_core/tool/mbed/mbed-sdk/libraries/rtos/rtx/TARGET_CORTEX_A/rt_Mutex.c

   1 /*----------------------------------------------------------------------------
   2  *      RL-ARM - RTX
   3  *----------------------------------------------------------------------------
   4  *      Name:    RT_MUTEX.C
   5  *      Purpose: Implements mutex synchronization objects
   6  *      Rev.:    V4.60
   7  *----------------------------------------------------------------------------
   8  *
   9  * Copyright (c) 1999-2009 KEIL, 2009-2012 ARM Germany GmbH
  10  * All rights reserved.
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions are met:
  13  *  - Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  *  - Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *  - Neither the name of ARM  nor the names of its contributors may be used
  19  *    to endorse or promote products derived from this software without
  20  *    specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  23  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDERS AND CONTRIBUTORS BE
  26  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  27  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  28  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  29  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  30  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  31  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  32  * POSSIBILITY OF SUCH DAMAGE.
  33  *---------------------------------------------------------------------------*/
  34
  35 #include "rt_TypeDef.h"
  36 #include "RTX_Config.h"
  37 #include "rt_List.h"
  38 #include "rt_Task.h"
  39 #include "rt_Mutex.h"
  40 #ifdef __CORTEX_A9
  41 #include "rt_HAL_CA.h"
  42 #else
  43 #include "rt_HAL_CM.h"
  44 #endif
  45
  46
  47 /*----------------------------------------------------------------------------
  48  *      Functions
  49  *---------------------------------------------------------------------------*/
  50
  51
  52 /*--------------------------- rt_mut_init -----------------------------------*/
  53
  54 void rt_mut_init (OS_ID mutex) {
  55   /* Initialize a mutex object */
  56   P_MUCB p_MCB = mutex;
  57
  58   p_MCB->cb_type = MUCB;
  59   p_MCB->prio    = 0;
  60   p_MCB->level   = 0;
  61   p_MCB->p_lnk   = NULL;
  62   p_MCB->owner   = NULL;
  63 }
  64
  65
  66 /*--------------------------- rt_mut_delete ---------------------------------*/
  67
  68 #ifdef __CMSIS_RTOS
  69 OS_RESULT rt_mut_delete (OS_ID mutex) {
  70   /* Delete a mutex object */
  71   P_MUCB p_MCB = mutex;
  72   P_TCB  p_TCB;
  73
  74   __DMB();
  75   /* Restore owner task's priority. */
  76   if (p_MCB->level != 0) {
  77     p_MCB->owner->prio = p_MCB->prio;
  78     if (p_MCB->owner != os_tsk.run) {
  79       rt_resort_prio (p_MCB->owner);
  80     }
  81   }
  82
  83   while (p_MCB->p_lnk != NULL) {
  84     /* A task is waiting for mutex. */
  85     p_TCB = rt_get_first ((P_XCB)p_MCB);
  86     rt_ret_val(p_TCB, 0/*osOK*/);
  87     rt_rmv_dly(p_TCB);
  88     p_TCB->state = READY;
  89     rt_put_prio (&os_rdy, p_TCB);
  90   }
  91
  92   if (os_rdy.p_lnk && (os_rdy.p_lnk->prio > os_tsk.run->prio)) {
  93     /* preempt running task */
  94     rt_put_prio (&os_rdy, os_tsk.run);
  95     os_tsk.run->state = READY;
  96     rt_dispatch (NULL);
  97   }
  98
  99   p_MCB->cb_type = 0;
 100
 101   return (OS_R_OK);
 102 }
 103 #endif
 104
 105
 106 /*--------------------------- rt_mut_release --------------------------------*/
 107
 108 OS_RESULT rt_mut_release (OS_ID mutex) {
 109   /* Release a mutex object */
 110   P_MUCB p_MCB = mutex;
 111   P_TCB  p_TCB;
 112
 113   if (p_MCB->level == 0 || p_MCB->owner != os_tsk.run) {
 114     /* Unbalanced mutex release or task is not the owner */
 115     return (OS_R_NOK);
 116   }
 117   __DMB();
 118   if (--p_MCB->level != 0) {
 119     return (OS_R_OK);
 120   }
 121   /* Restore owner task's priority. */
 122   os_tsk.run->prio = p_MCB->prio;
 123   if (p_MCB->p_lnk != NULL) {
 124     /* A task is waiting for mutex. */
 125     p_TCB = rt_get_first ((P_XCB)p_MCB);
 126 #ifdef __CMSIS_RTOS
 127     rt_ret_val(p_TCB, 0/*osOK*/);
 128 #else
 129     rt_ret_val(p_TCB, OS_R_MUT);
 130 #endif
 131     rt_rmv_dly (p_TCB);
 132     /* A waiting task becomes the owner of this mutex. */
 133     p_MCB->level     = 1;
 134     p_MCB->owner     = p_TCB;
 135     p_MCB->prio      = p_TCB->prio;
 136     /* Priority inversion, check which task continues. */
 137     if (os_tsk.run->prio >= rt_rdy_prio()) {
 138       rt_dispatch (p_TCB);
 139     }
 140     else {
 141       /* Ready task has higher priority than running task. */
 142       rt_put_prio (&os_rdy, os_tsk.run);
 143       rt_put_prio (&os_rdy, p_TCB);
 144       os_tsk.run->state = READY;
 145       p_TCB->state      = READY;
 146       rt_dispatch (NULL);
 147     }
 148   }
 149   else {
 150     /* Check if own priority raised by priority inversion. */
 151     if (rt_rdy_prio() > os_tsk.run->prio) {
 152       rt_put_prio (&os_rdy, os_tsk.run);
 153       os_tsk.run->state = READY;
 154       rt_dispatch (NULL);
 155     }
 156   }
 157   return (OS_R_OK);
 158 }
 159
 160
 161 /*--------------------------- rt_mut_wait -----------------------------------*/
 162
 163 OS_RESULT rt_mut_wait (OS_ID mutex, U16 timeout) {
 164   /* Wait for a mutex, continue when mutex is free. */
 165   P_MUCB p_MCB = mutex;
 166
 167   if (p_MCB->level == 0) {
 168     p_MCB->owner = os_tsk.run;
 169     p_MCB->prio  = os_tsk.run->prio;
 170     goto inc;
 171   }
 172   if (p_MCB->owner == os_tsk.run) {
 173     /* OK, running task is the owner of this mutex. */
 174 inc:p_MCB->level++;
 175     __DMB();
 176     return (OS_R_OK);
 177   }
 178   /* Mutex owned by another task, wait until released. */
 179   if (timeout == 0) {
 180     return (OS_R_TMO);
 181   }
 182   /* Raise the owner task priority if lower than current priority. */
 183   /* This priority inversion is called priority inheritance.       */
 184   if (p_MCB->prio < os_tsk.run->prio) {
 185     p_MCB->owner->prio = os_tsk.run->prio;
 186     rt_resort_prio (p_MCB->owner);
 187   }
 188   if (p_MCB->p_lnk != NULL) {
 189     rt_put_prio ((P_XCB)p_MCB, os_tsk.run);
 190   }
 191   else {
 192     p_MCB->p_lnk = os_tsk.run;
 193     os_tsk.run->p_lnk  = NULL;
 194     os_tsk.run->p_rlnk = (P_TCB)p_MCB;
 195   }
 196   rt_block(timeout, WAIT_MUT);
 197   return (OS_R_TMO);
 198 }
 199
 200
 201 /*----------------------------------------------------------------------------
 202  * end of file
 203  *---------------------------------------------------------------------------*/
 204