tool/mbed/mbed-sdk/libraries/rtos/rtx/TARGET_CORTEX_M/rt_Semaphore.c

   1 /*----------------------------------------------------------------------------
   2  *      RL-ARM - RTX
   3  *----------------------------------------------------------------------------
   4  *      Name:    RT_SEMAPHORE.C
   5  *      Purpose: Implements binary and counting semaphores
   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_System.h"
  38 #include "rt_List.h"
  39 #include "rt_Task.h"
  40 #include "rt_Semaphore.h"
  41 #include "rt_HAL_CM.h"
  42
  43
  44 /*----------------------------------------------------------------------------
  45  *      Functions
  46  *---------------------------------------------------------------------------*/
  47
  48
  49 /*--------------------------- rt_sem_init -----------------------------------*/
  50
  51 void rt_sem_init (OS_ID semaphore, U16 token_count) {
  52   /* Initialize a semaphore */
  53   P_SCB p_SCB = semaphore;
  54
  55   p_SCB->cb_type = SCB;
  56   p_SCB->p_lnk  = NULL;
  57   p_SCB->tokens = token_count;
  58 }
  59
  60
  61 /*--------------------------- rt_sem_delete ---------------------------------*/
  62
  63 #ifdef __CMSIS_RTOS
  64 OS_RESULT rt_sem_delete (OS_ID semaphore) {
  65   /* Delete semaphore */
  66   P_SCB p_SCB = semaphore;
  67   P_TCB p_TCB;
  68
  69   while (p_SCB->p_lnk != NULL) {
  70     /* A task is waiting for token */
  71     p_TCB = rt_get_first ((P_XCB)p_SCB);
  72     rt_ret_val(p_TCB, 0);
  73     rt_rmv_dly(p_TCB);
  74     p_TCB->state = READY;
  75     rt_put_prio (&os_rdy, p_TCB);
  76   }
  77
  78   if (os_rdy.p_lnk && (os_rdy.p_lnk->prio > os_tsk.run->prio)) {
  79     /* preempt running task */
  80     rt_put_prio (&os_rdy, os_tsk.run);
  81     os_tsk.run->state = READY;
  82     rt_dispatch (NULL);
  83   }
  84
  85   p_SCB->cb_type = 0;
  86
  87   return (OS_R_OK);
  88 }
  89 #endif
  90
  91
  92 /*--------------------------- rt_sem_send -----------------------------------*/
  93
  94 OS_RESULT rt_sem_send (OS_ID semaphore) {
  95   /* Return a token to semaphore */
  96   P_SCB p_SCB = semaphore;
  97   P_TCB p_TCB;
  98
  99   if (p_SCB->p_lnk != NULL) {
 100     /* A task is waiting for token */
 101     p_TCB = rt_get_first ((P_XCB)p_SCB);
 102 #ifdef __CMSIS_RTOS
 103     rt_ret_val(p_TCB, 1);
 104 #else
 105     rt_ret_val(p_TCB, OS_R_SEM);
 106 #endif
 107     rt_rmv_dly (p_TCB);
 108     rt_dispatch (p_TCB);
 109   }
 110   else {
 111     /* Store token. */
 112     p_SCB->tokens++;
 113   }
 114   return (OS_R_OK);
 115 }
 116
 117
 118 /*--------------------------- rt_sem_wait -----------------------------------*/
 119
 120 OS_RESULT rt_sem_wait (OS_ID semaphore, U16 timeout) {
 121   /* Obtain a token; possibly wait for it */
 122   P_SCB p_SCB = semaphore;
 123
 124   if (p_SCB->tokens) {
 125     p_SCB->tokens--;
 126     return (OS_R_OK);
 127   }
 128   /* No token available: wait for one */
 129   if (timeout == 0) {
 130     return (OS_R_TMO);
 131   }
 132   if (p_SCB->p_lnk != NULL) {
 133     rt_put_prio ((P_XCB)p_SCB, os_tsk.run);
 134   }
 135   else {
 136     p_SCB->p_lnk = os_tsk.run;
 137     os_tsk.run->p_lnk = NULL;
 138     os_tsk.run->p_rlnk = (P_TCB)p_SCB;
 139   }
 140   rt_block(timeout, WAIT_SEM);
 141   return (OS_R_TMO);
 142 }
 143
 144
 145 /*--------------------------- isr_sem_send ----------------------------------*/
 146
 147 void isr_sem_send (OS_ID semaphore) {
 148   /* Same function as "os_sem"send", but to be called by ISRs */
 149   P_SCB p_SCB = semaphore;
 150
 151   rt_psq_enq (p_SCB, 0);
 152   rt_psh_req ();
 153 }
 154
 155
 156 /*--------------------------- rt_sem_psh ------------------------------------*/
 157
 158 void rt_sem_psh (P_SCB p_CB) {
 159   /* Check if task has to be waken up */
 160   P_TCB p_TCB;
 161
 162   if (p_CB->p_lnk != NULL) {
 163     /* A task is waiting for token */
 164     p_TCB = rt_get_first ((P_XCB)p_CB);
 165     rt_rmv_dly (p_TCB);
 166     p_TCB->state   = READY;
 167 #ifdef __CMSIS_RTOS
 168     rt_ret_val(p_TCB, 1);
 169 #else
 170     rt_ret_val(p_TCB, OS_R_SEM);
 171 #endif
 172     rt_put_prio (&os_rdy, p_TCB);
 173   }
 174   else {
 175     /* Store token */
 176     p_CB->tokens++;
 177   }
 178 }
 179
 180 /*----------------------------------------------------------------------------
 181  * end of file
 182  *---------------------------------------------------------------------------*/
 183