1 /*----------------------------------------------------------------------------
3 *----------------------------------------------------------------------------
5 * Purpose: Implements mutex synchronization objects
7 *----------------------------------------------------------------------------
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.
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 *---------------------------------------------------------------------------*/
35 #include "rt_TypeDef.h"
40 #include "rt_HAL_CM.h"
43 /*----------------------------------------------------------------------------
45 *---------------------------------------------------------------------------*/
48 /*--------------------------- rt_mut_init -----------------------------------*/
50 void rt_mut_init (OS_ID mutex) {
51 /* Initialize a mutex object */
54 p_MCB->cb_type = MUCB;
62 /*--------------------------- rt_mut_delete ---------------------------------*/
65 OS_RESULT rt_mut_delete (OS_ID mutex) {
66 /* Delete a mutex object */
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);
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*/);
84 rt_put_prio (&os_rdy, p_TCB);
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;
101 /*--------------------------- rt_mut_release --------------------------------*/
103 OS_RESULT rt_mut_release (OS_ID mutex) {
104 /* Release a mutex object */
105 P_MUCB p_MCB = mutex;
108 if (p_MCB->level == 0 || p_MCB->owner != os_tsk.run) {
109 /* Unbalanced mutex release or task is not the owner */
112 if (--p_MCB->level != 0) {
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);
121 rt_ret_val(p_TCB, 0/*osOK*/);
123 rt_ret_val(p_TCB, OS_R_MUT);
126 /* A waiting task becomes the owner of this mutex. */
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()) {
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;
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;
155 /*--------------------------- rt_mut_wait -----------------------------------*/
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;
161 if (p_MCB->level == 0) {
162 p_MCB->owner = os_tsk.run;
163 p_MCB->prio = os_tsk.run->prio;
166 if (p_MCB->owner == os_tsk.run) {
167 /* OK, running task is the owner of this mutex. */
171 /* Mutex owned by another task, wait until released. */
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);
181 if (p_MCB->p_lnk != NULL) {
182 rt_put_prio ((P_XCB)p_MCB, os_tsk.run);
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;
189 rt_block(timeout, WAIT_MUT);
194 /*----------------------------------------------------------------------------
196 *---------------------------------------------------------------------------*/