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/*----------------------------------------------------------------------------
* RL-ARM - RTX
*----------------------------------------------------------------------------
* Name: RT_MUTEX.C
* Purpose: Implements mutex synchronization objects
* Rev.: V4.60
*----------------------------------------------------------------------------
*
* Copyright (c) 1999-2009 KEIL, 2009-2012 ARM Germany GmbH
* All rights reserved.
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - Neither the name of ARM nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDERS AND CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*---------------------------------------------------------------------------*/
#include "rt_TypeDef.h"
#include "RTX_Conf.h"
#include "rt_List.h"
#include "rt_Task.h"
#include "rt_Mutex.h"
#include "rt_HAL_CM.h"
/*----------------------------------------------------------------------------
* Functions
*---------------------------------------------------------------------------*/
/*--------------------------- rt_mut_init -----------------------------------*/
void rt_mut_init (OS_ID mutex) {
/* Initialize a mutex object */
P_MUCB p_MCB = mutex;
p_MCB->cb_type = MUCB;
p_MCB->prio = 0;
p_MCB->level = 0;
p_MCB->p_lnk = NULL;
p_MCB->owner = NULL;
}
/*--------------------------- rt_mut_delete ---------------------------------*/
#ifdef __CMSIS_RTOS
OS_RESULT rt_mut_delete (OS_ID mutex) {
/* Delete a mutex object */
P_MUCB p_MCB = mutex;
P_TCB p_TCB;
/* Restore owner task's priority. */
if (p_MCB->level != 0) {
p_MCB->owner->prio = p_MCB->prio;
if (p_MCB->owner != os_tsk.run) {
rt_resort_prio (p_MCB->owner);
}
}
while (p_MCB->p_lnk != NULL) {
/* A task is waiting for mutex. */
p_TCB = rt_get_first ((P_XCB)p_MCB);
rt_ret_val(p_TCB, 0/*osOK*/);
rt_rmv_dly(p_TCB);
p_TCB->state = READY;
rt_put_prio (&os_rdy, p_TCB);
}
if (os_rdy.p_lnk && (os_rdy.p_lnk->prio > os_tsk.run->prio)) {
/* preempt running task */
rt_put_prio (&os_rdy, os_tsk.run);
os_tsk.run->state = READY;
rt_dispatch (NULL);
}
p_MCB->cb_type = 0;
return (OS_R_OK);
}
#endif
/*--------------------------- rt_mut_release --------------------------------*/
OS_RESULT rt_mut_release (OS_ID mutex) {
/* Release a mutex object */
P_MUCB p_MCB = mutex;
P_TCB p_TCB;
if (p_MCB->level == 0 || p_MCB->owner != os_tsk.run) {
/* Unbalanced mutex release or task is not the owner */
return (OS_R_NOK);
}
if (--p_MCB->level != 0) {
return (OS_R_OK);
}
/* Restore owner task's priority. */
os_tsk.run->prio = p_MCB->prio;
if (p_MCB->p_lnk != NULL) {
/* A task is waiting for mutex. */
p_TCB = rt_get_first ((P_XCB)p_MCB);
#ifdef __CMSIS_RTOS
rt_ret_val(p_TCB, 0/*osOK*/);
#else
rt_ret_val(p_TCB, OS_R_MUT);
#endif
rt_rmv_dly (p_TCB);
/* A waiting task becomes the owner of this mutex. */
p_MCB->level = 1;
p_MCB->owner = p_TCB;
p_MCB->prio = p_TCB->prio;
/* Priority inversion, check which task continues. */
if (os_tsk.run->prio >= rt_rdy_prio()) {
rt_dispatch (p_TCB);
}
else {
/* Ready task has higher priority than running task. */
rt_put_prio (&os_rdy, os_tsk.run);
rt_put_prio (&os_rdy, p_TCB);
os_tsk.run->state = READY;
p_TCB->state = READY;
rt_dispatch (NULL);
}
}
else {
/* Check if own priority raised by priority inversion. */
if (rt_rdy_prio() > os_tsk.run->prio) {
rt_put_prio (&os_rdy, os_tsk.run);
os_tsk.run->state = READY;
rt_dispatch (NULL);
}
}
return (OS_R_OK);
}
/*--------------------------- rt_mut_wait -----------------------------------*/
OS_RESULT rt_mut_wait (OS_ID mutex, U16 timeout) {
/* Wait for a mutex, continue when mutex is free. */
P_MUCB p_MCB = mutex;
if (p_MCB->level == 0) {
p_MCB->owner = os_tsk.run;
p_MCB->prio = os_tsk.run->prio;
goto inc;
}
if (p_MCB->owner == os_tsk.run) {
/* OK, running task is the owner of this mutex. */
inc:p_MCB->level++;
return (OS_R_OK);
}
/* Mutex owned by another task, wait until released. */
if (timeout == 0) {
return (OS_R_TMO);
}
/* Raise the owner task priority if lower than current priority. */
/* This priority inversion is called priority inheritance. */
if (p_MCB->prio < os_tsk.run->prio) {
p_MCB->owner->prio = os_tsk.run->prio;
rt_resort_prio (p_MCB->owner);
}
if (p_MCB->p_lnk != NULL) {
rt_put_prio ((P_XCB)p_MCB, os_tsk.run);
}
else {
p_MCB->p_lnk = os_tsk.run;
os_tsk.run->p_lnk = NULL;
os_tsk.run->p_rlnk = (P_TCB)p_MCB;
}
rt_block(timeout, WAIT_MUT);
return (OS_R_TMO);
}
/*----------------------------------------------------------------------------
* end of file
*---------------------------------------------------------------------------*/
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