Diff: mbed-rtos/rtx/rt_Mutex.c

Revision:

0:1496281373a5

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-rtos/rtx/rt_Mutex.c	Thu Oct 17 13:26:38 2013 +0000
@@ -0,0 +1,197 @@
+/*----------------------------------------------------------------------------
+ *      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
+ *---------------------------------------------------------------------------*/
+