tmk_core/tool/mbed/mbed-sdk/libraries/rtos/rtx/TARGET_CORTEX_A/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_Config.h"
  37 #include "rt_System.h"
  38 #include "rt_List.h"
  39 #include "rt_Task.h"
  40 #include "rt_Semaphore.h"
  41 #ifdef __CORTEX_A9
  42 #include "rt_HAL_CA.h"
  43 #else
  44 #include "rt_HAL_CM.h"
  45 #endif
  46
  47
  48 /*----------------------------------------------------------------------------
  49  *      Functions
  50  *---------------------------------------------------------------------------*/
  51
  52
  53 /*--------------------------- rt_sem_init -----------------------------------*/
  54
  55 void rt_sem_init (OS_ID semaphore, U16 token_count) {
  56   /* Initialize a semaphore */
  57   P_SCB p_SCB = semaphore;
  58
  59   p_SCB->cb_type = SCB;
  60   p_SCB->p_lnk  = NULL;
  61   p_SCB->tokens = token_count;
  62 }
  63
  64
  65 /*--------------------------- rt_sem_delete ---------------------------------*/
  66
  67 #ifdef __CMSIS_RTOS
  68 OS_RESULT rt_sem_delete (OS_ID semaphore) {
  69   /* Delete semaphore */
  70   P_SCB p_SCB = semaphore;
  71   P_TCB p_TCB;
  72
  73   __DMB();
  74   while (p_SCB->p_lnk != NULL) {
  75     /* A task is waiting for token */
  76     p_TCB = rt_get_first ((P_XCB)p_SCB);
  77     rt_ret_val(p_TCB, 0);
  78     rt_rmv_dly(p_TCB);
  79     p_TCB->state = READY;
  80     rt_put_prio (&os_rdy, p_TCB);
  81   }
  82
  83   if (os_rdy.p_lnk && (os_rdy.p_lnk->prio > os_tsk.run->prio)) {
  84     /* preempt running task */
  85     rt_put_prio (&os_rdy, os_tsk.run);
  86     os_tsk.run->state = READY;
  87     rt_dispatch (NULL);
  88   }
  89
  90   p_SCB->cb_type = 0;
  91
  92   return (OS_R_OK);
  93 }
  94 #endif
  95
  96
  97 /*--------------------------- rt_sem_send -----------------------------------*/
  98
  99 OS_RESULT rt_sem_send (OS_ID semaphore) {
 100   /* Return a token to semaphore */
 101   P_SCB p_SCB = semaphore;
 102   P_TCB p_TCB;
 103
 104   __DMB();
 105   if (p_SCB->p_lnk != NULL) {
 106     /* A task is waiting for token */
 107     p_TCB = rt_get_first ((P_XCB)p_SCB);
 108 #ifdef __CMSIS_RTOS
 109     rt_ret_val(p_TCB, 1);
 110 #else
 111     rt_ret_val(p_TCB, OS_R_SEM);
 112 #endif
 113     rt_rmv_dly (p_TCB);
 114     rt_dispatch (p_TCB);
 115   }
 116   else {
 117     /* Store token. */
 118     p_SCB->tokens++;
 119   }
 120   return (OS_R_OK);
 121 }
 122
 123
 124 /*--------------------------- rt_sem_wait -----------------------------------*/
 125
 126 OS_RESULT rt_sem_wait (OS_ID semaphore, U16 timeout) {
 127   /* Obtain a token; possibly wait for it */
 128   P_SCB p_SCB = semaphore;
 129
 130   if (p_SCB->tokens) {
 131     p_SCB->tokens--;
 132     __DMB();
 133     return (OS_R_OK);
 134   }
 135   /* No token available: wait for one */
 136   if (timeout == 0) {
 137     return (OS_R_TMO);
 138   }
 139   if (p_SCB->p_lnk != NULL) {
 140     rt_put_prio ((P_XCB)p_SCB, os_tsk.run);
 141   }
 142   else {
 143     p_SCB->p_lnk = os_tsk.run;
 144     os_tsk.run->p_lnk = NULL;
 145     os_tsk.run->p_rlnk = (P_TCB)p_SCB;
 146   }
 147   rt_block(timeout, WAIT_SEM);
 148   return (OS_R_TMO);
 149 }
 150
 151
 152 /*--------------------------- isr_sem_send ----------------------------------*/
 153
 154 void isr_sem_send (OS_ID semaphore) {
 155   /* Same function as "os_sem"send", but to be called by ISRs */
 156   P_SCB p_SCB = semaphore;
 157
 158   rt_psq_enq (p_SCB, 0);
 159   rt_psh_req ();
 160 }
 161
 162
 163 /*--------------------------- rt_sem_psh ------------------------------------*/
 164
 165 void rt_sem_psh (P_SCB p_CB) {
 166   /* Check if task has to be waken up */
 167   P_TCB p_TCB;
 168
 169   __DMB();
 170   if (p_CB->p_lnk != NULL) {
 171     /* A task is waiting for token */
 172     p_TCB = rt_get_first ((P_XCB)p_CB);
 173     rt_rmv_dly (p_TCB);
 174     p_TCB->state   = READY;
 175 #ifdef __CMSIS_RTOS
 176     rt_ret_val(p_TCB, 1);
 177 #else
 178     rt_ret_val(p_TCB, OS_R_SEM);
 179 #endif
 180     rt_put_prio (&os_rdy, p_TCB);
 181   }
 182   else {
 183     /* Store token */
 184     p_CB->tokens++;
 185   }
 186 }
 187
 188 /*----------------------------------------------------------------------------
 189  * end of file
 190  *---------------------------------------------------------------------------*/
 191