tmk_core/tool/mbed/mbed-sdk/libraries/rtos/rtx/TARGET_CORTEX_M/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_Conf.h"
  37 #include "rt_List.h"
  38 #include "rt_Task.h"
  39 #include "rt_Mutex.h"
  40 #include "rt_HAL_CM.h"
  41
  42
  43 /*----------------------------------------------------------------------------
  44  *      Functions
  45  *---------------------------------------------------------------------------*/
  46
  47
  48 /*--------------------------- rt_mut_init -----------------------------------*/
  49
  50 void rt_mut_init (OS_ID mutex) {
  51   /* Initialize a mutex object */
  52   P_MUCB p_MCB = mutex;
  53
  54   p_MCB->cb_type = MUCB;
  55   p_MCB->prio    = 0;
  56   p_MCB->level   = 0;
  57   p_MCB->p_lnk   = NULL;
  58   p_MCB->owner   = NULL;
  59 }
  60
  61
  62 /*--------------------------- rt_mut_delete ---------------------------------*/
  63
  64 #ifdef __CMSIS_RTOS
  65 OS_RESULT rt_mut_delete (OS_ID mutex) {
  66   /* Delete a mutex object */
  67   P_MUCB p_MCB = mutex;
  68   P_TCB  p_TCB;
  69
  70   /* Restore owner task's priority. */
  71   if (p_MCB->level != 0) {
  72     p_MCB->owner->prio = p_MCB->prio;
  73     if (p_MCB->owner != os_tsk.run) {
  74       rt_resort_prio (p_MCB->owner);
  75     }
  76   }
  77
  78   while (p_MCB->p_lnk != NULL) {
  79     /* A task is waiting for mutex. */
  80     p_TCB = rt_get_first ((P_XCB)p_MCB);
  81     rt_ret_val(p_TCB, 0/*osOK*/);
  82     rt_rmv_dly(p_TCB);
  83     p_TCB->state = READY;
  84     rt_put_prio (&os_rdy, p_TCB);
  85   }
  86
  87   if (os_rdy.p_lnk && (os_rdy.p_lnk->prio > os_tsk.run->prio)) {
  88     /* preempt running task */
  89     rt_put_prio (&os_rdy, os_tsk.run);
  90     os_tsk.run->state = READY;
  91     rt_dispatch (NULL);
  92   }
  93
  94   p_MCB->cb_type = 0;
  95
  96   return (OS_R_OK);
  97 }
  98 #endif
  99
 100
 101 /*--------------------------- rt_mut_release --------------------------------*/
 102
 103 OS_RESULT rt_mut_release (OS_ID mutex) {
 104   /* Release a mutex object */
 105   P_MUCB p_MCB = mutex;
 106   P_TCB  p_TCB;
 107
 108   if (p_MCB->level == 0 || p_MCB->owner != os_tsk.run) {
 109     /* Unbalanced mutex release or task is not the owner */
 110     return (OS_R_NOK);
 111   }
 112   if (--p_MCB->level != 0) {
 113     return (OS_R_OK);
 114   }
 115   /* Restore owner task's priority. */
 116   os_tsk.run->prio = p_MCB->prio;
 117   if (p_MCB->p_lnk != NULL) {
 118     /* A task is waiting for mutex. */
 119     p_TCB = rt_get_first ((P_XCB)p_MCB);
 120 #ifdef __CMSIS_RTOS
 121     rt_ret_val(p_TCB, 0/*osOK*/);
 122 #else
 123     rt_ret_val(p_TCB, OS_R_MUT);
 124 #endif
 125     rt_rmv_dly (p_TCB);
 126     /* A waiting task becomes the owner of this mutex. */
 127     p_MCB->level     = 1;
 128     p_MCB->owner     = p_TCB;
 129     p_MCB->prio      = p_TCB->prio;
 130     /* Priority inversion, check which task continues. */
 131     if (os_tsk.run->prio >= rt_rdy_prio()) {
 132       rt_dispatch (p_TCB);
 133     }
 134     else {
 135       /* Ready task has higher priority than running task. */
 136       rt_put_prio (&os_rdy, os_tsk.run);
 137       rt_put_prio (&os_rdy, p_TCB);
 138       os_tsk.run->state = READY;
 139       p_TCB->state      = READY;
 140       rt_dispatch (NULL);
 141     }
 142   }
 143   else {
 144     /* Check if own priority raised by priority inversion. */
 145     if (rt_rdy_prio() > os_tsk.run->prio) {
 146       rt_put_prio (&os_rdy, os_tsk.run);
 147       os_tsk.run->state = READY;
 148       rt_dispatch (NULL);
 149     }
 150   }
 151   return (OS_R_OK);
 152 }
 153
 154
 155 /*--------------------------- rt_mut_wait -----------------------------------*/
 156
 157 OS_RESULT rt_mut_wait (OS_ID mutex, U16 timeout) {
 158   /* Wait for a mutex, continue when mutex is free. */
 159   P_MUCB p_MCB = mutex;
 160
 161   if (p_MCB->level == 0) {
 162     p_MCB->owner = os_tsk.run;
 163     p_MCB->prio  = os_tsk.run->prio;
 164     goto inc;
 165   }
 166   if (p_MCB->owner == os_tsk.run) {
 167     /* OK, running task is the owner of this mutex. */
 168 inc:p_MCB->level++;
 169     return (OS_R_OK);
 170   }
 171   /* Mutex owned by another task, wait until released. */
 172   if (timeout == 0) {
 173     return (OS_R_TMO);
 174   }
 175   /* Raise the owner task priority if lower than current priority. */
 176   /* This priority inversion is called priority inheritance.       */
 177   if (p_MCB->prio < os_tsk.run->prio) {
 178     p_MCB->owner->prio = os_tsk.run->prio;
 179     rt_resort_prio (p_MCB->owner);
 180   }
 181   if (p_MCB->p_lnk != NULL) {
 182     rt_put_prio ((P_XCB)p_MCB, os_tsk.run);
 183   }
 184   else {
 185     p_MCB->p_lnk = os_tsk.run;
 186     os_tsk.run->p_lnk  = NULL;
 187     os_tsk.run->p_rlnk = (P_TCB)p_MCB;
 188   }
 189   rt_block(timeout, WAIT_MUT);
 190   return (OS_R_TMO);
 191 }
 192
 193
 194 /*----------------------------------------------------------------------------
 195  * end of file
 196  *---------------------------------------------------------------------------*/
 197