Diff: source/rtos/rt_Mutex.c

Revision:

0:01f31e923fe2

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/source/rtos/rt_Mutex.c	Tue Apr 07 12:55:42 2020 +0200
@@ -0,0 +1,142 @@
+/**
+ * @file    rt_Mutex.c
+ * @brief   
+ *
+ * DAPLink Interface Firmware
+ * Copyright (c) 2009-2016, ARM Limited, All Rights Reserved
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "rt_TypeDef.h"
+#include "RTX_Config.h"
+#include "rt_List.h"
+#include "rt_Task.h"
+#include "rt_Mutex.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_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);
+    p_TCB->ret_val = OS_R_MUT;
+    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);
+    }
+    os_tsk.run->ret_val = OS_R_OK;
+  }
+  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);
+      os_tsk.run->ret_val = OS_R_OK;
+    }
+  }
+  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
+ *---------------------------------------------------------------------------*/
+