rt_Mailbox.c

00001 /**
00002  * @file    rt_Mailbox.c
00003  * @brief   
00004  *
00005  * DAPLink Interface Firmware
00006  * Copyright (c) 2009-2016, ARM Limited, All Rights Reserved
00007  * SPDX-License-Identifier: Apache-2.0
00008  *
00009  * Licensed under the Apache License, Version 2.0 (the "License"); you may
00010  * not use this file except in compliance with the License.
00011  * You may obtain a copy of the License at
00012  *
00013  * http://www.apache.org/licenses/LICENSE-2.0
00014  *
00015  * Unless required by applicable law or agreed to in writing, software
00016  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
00017  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00018  * See the License for the specific language governing permissions and
00019  * limitations under the License.
00020  */
00021 
00022 #include "rt_TypeDef.h"
00023 #include "RTX_Config.h"
00024 #include "rt_System.h"
00025 #include "rt_List.h"
00026 #include "rt_Mailbox.h"
00027 #include "rt_Task.h"
00028 #include "rt_HAL_CM.h"
00029 
00030 
00031 /*----------------------------------------------------------------------------
00032  *      Functions
00033  *---------------------------------------------------------------------------*/
00034 
00035 
00036 /*--------------------------- rt_mbx_init -----------------------------------*/
00037 
00038 void rt_mbx_init (OS_ID mailbox, U16 mbx_size) {
00039   /* Initialize a mailbox */
00040   P_MCB p_MCB = mailbox;
00041 
00042   p_MCB->cb_type = MCB;
00043   p_MCB->isr_st  = 0;
00044   p_MCB->p_lnk   = NULL;
00045   p_MCB->first   = 0;
00046   p_MCB->last    = 0;
00047   p_MCB->count   = 0;
00048   p_MCB->size    = (mbx_size + sizeof(void *) - sizeof(struct OS_MCB)) /
00049                                                      (U32)sizeof (void *);
00050 }
00051 
00052 
00053 /*--------------------------- rt_mbx_send -----------------------------------*/
00054 
00055 OS_RESULT rt_mbx_send (OS_ID mailbox, void *p_msg, U16 timeout) {
00056   /* Send message to a mailbox */
00057   P_MCB p_MCB = mailbox;
00058   P_TCB p_TCB;
00059 
00060   if (p_MCB->p_lnk != NULL && p_MCB->count == 0) {
00061     /* A task is waiting for message */
00062     p_TCB = rt_get_first ((P_XCB)p_MCB);
00063     *p_TCB->msg    = p_msg;
00064     p_TCB->ret_val = OS_R_MBX;
00065     rt_rmv_dly (p_TCB);
00066     rt_dispatch (p_TCB);
00067     os_tsk.run->ret_val = OS_R_OK;
00068   }
00069   else {
00070     /* Store message in mailbox queue */
00071     if (p_MCB->count == p_MCB->size) {
00072       /* No free message entry, wait for one. If message queue is full, */
00073       /* then no task is waiting for message. The 'p_MCB->p_lnk' list   */
00074       /* pointer can now be reused for send message waits task list.    */
00075       if (timeout == 0) {
00076         return (OS_R_TMO);
00077       }
00078       if (p_MCB->p_lnk != NULL) {
00079         rt_put_prio ((P_XCB)p_MCB, os_tsk.run);
00080       }
00081       else {
00082         p_MCB->p_lnk = os_tsk.run;
00083         os_tsk.run->p_lnk  = NULL;
00084         os_tsk.run->p_rlnk = (P_TCB)p_MCB;
00085         /* Signal the 'isr_mbx_receive ()' that the task is waiting */
00086         /* to send a message */
00087         p_MCB->isr_st = 1;
00088       }
00089       os_tsk.run->msg = p_msg;
00090       rt_block (timeout, WAIT_MBX);
00091       return (OS_R_TMO);
00092     }
00093     /* Yes, there is a free entry in a mailbox. */
00094     p_MCB->msg[p_MCB->first] = p_msg;
00095     rt_inc (&p_MCB->count);
00096     if (++p_MCB->first == p_MCB->size) {
00097       p_MCB->first = 0;
00098     }
00099   }
00100   return (OS_R_OK);
00101 }
00102 
00103 
00104 /*--------------------------- rt_mbx_wait -----------------------------------*/
00105 
00106 OS_RESULT rt_mbx_wait (OS_ID mailbox, void **message, U16 timeout) {
00107   /* Receive a message; possibly wait for it */
00108   P_MCB p_MCB = mailbox;
00109   P_TCB p_TCB;
00110 
00111   /* If a message is available in the fifo buffer */
00112   /* remove it from the fifo buffer and return. */
00113   if (p_MCB->count) {
00114     *message = p_MCB->msg[p_MCB->last];
00115     if (++p_MCB->last == p_MCB->size) {
00116       p_MCB->last = 0;
00117     }
00118     if (p_MCB->p_lnk != NULL) {
00119       /* A task is waiting to send message */
00120       p_TCB = rt_get_first ((P_XCB)p_MCB);
00121       p_TCB->ret_val = OS_R_OK;
00122       p_MCB->msg[p_MCB->first] = p_TCB->msg;
00123       if (++p_MCB->first == p_MCB->size) {
00124         p_MCB->first = 0;
00125       }
00126       rt_rmv_dly (p_TCB);
00127       rt_dispatch (p_TCB);
00128       os_tsk.run->ret_val = OS_R_OK;
00129     }
00130     else {
00131       rt_dec (&p_MCB->count);
00132     }
00133     return (OS_R_OK);
00134   }
00135   /* No message available: wait for one */
00136   if (timeout == 0) {
00137     return (OS_R_TMO);
00138   }
00139   if (p_MCB->p_lnk != NULL) {
00140     rt_put_prio ((P_XCB)p_MCB, os_tsk.run);
00141   }
00142   else {
00143     p_MCB->p_lnk = os_tsk.run;
00144     os_tsk.run->p_lnk = NULL;
00145     os_tsk.run->p_rlnk = (P_TCB)p_MCB;
00146   }
00147   rt_block(timeout, WAIT_MBX);
00148   os_tsk.run->msg = message;
00149   return (OS_R_TMO);
00150 }
00151 
00152 
00153 /*--------------------------- rt_mbx_check ----------------------------------*/
00154 
00155 OS_RESULT rt_mbx_check (OS_ID mailbox) {
00156   /* Check for free space in a mailbox. Returns the number of messages     */
00157   /* that can be stored to a mailbox. It returns 0 when mailbox is full.   */
00158   P_MCB p_MCB = mailbox;
00159 
00160   return (p_MCB->size - p_MCB->count);
00161 }
00162 
00163 
00164 /*--------------------------- isr_mbx_send ----------------------------------*/
00165 
00166 void isr_mbx_send (OS_ID mailbox, void *p_msg) {
00167   /* Same function as "os_mbx_send", but to be called by ISRs. */
00168   P_MCB p_MCB = mailbox;
00169 
00170   rt_psq_enq (p_MCB, (U32)p_msg);
00171   rt_psh_req ();
00172 }
00173 
00174 
00175 /*--------------------------- isr_mbx_receive -------------------------------*/
00176 
00177 OS_RESULT isr_mbx_receive (OS_ID mailbox, void **message) {
00178   /* Receive a message in the interrupt function. The interrupt function   */
00179   /* should not wait for a message since this would block the rtx os.      */
00180   P_MCB p_MCB = mailbox;
00181 
00182   if (p_MCB->count) {
00183     /* A message is available in the fifo buffer. */
00184     *message = p_MCB->msg[p_MCB->last];
00185     if (p_MCB->isr_st == 1) {
00186       /* A task is locked waiting to send message */
00187       p_MCB->isr_st = 2;
00188       rt_psq_enq (p_MCB, 0);
00189       rt_psh_req ();
00190     }
00191     rt_dec (&p_MCB->count);
00192     if (++p_MCB->last == p_MCB->size) {
00193       p_MCB->last = 0;
00194     }
00195     return (OS_R_MBX);
00196   }
00197   return (OS_R_OK);
00198 }
00199 
00200 
00201 /*--------------------------- rt_mbx_psh ------------------------------------*/
00202 
00203 void rt_mbx_psh (P_MCB p_CB, void *p_msg) {
00204   /* Store the message to the mailbox queue or pass it to task directly. */
00205   P_TCB p_TCB;
00206 
00207   /* Check if this was an 'isr_mbx_receive ()' post service request.   */
00208   if (p_CB->p_lnk != NULL && p_CB->isr_st == 2) {
00209     /* A task is waiting to send message, remove it from the waiting list. */
00210     p_CB->isr_st = 0;
00211     p_TCB = rt_get_first ((P_XCB)p_CB);
00212     p_TCB->ret_val = OS_R_OK;
00213     /* Store the message to the mailbox queue. */
00214     p_CB->msg[p_CB->first] = p_TCB->msg;
00215     rt_inc (&p_CB->count);
00216     if (++p_CB->first == p_CB->size) {
00217       p_CB->first = 0;
00218     }
00219     goto rdy;
00220   }
00221   /* A task is waiting for message, pass the message to task directly. */
00222   if (p_CB->p_lnk != NULL && p_CB->count == 0) {
00223     p_TCB = rt_get_first ((P_XCB)p_CB);
00224     *p_TCB->msg = p_msg;
00225     p_TCB->ret_val = OS_R_MBX;
00226 rdy:p_TCB->state = READY;
00227     rt_rmv_dly (p_TCB);
00228     rt_put_prio (&os_rdy, p_TCB);
00229   }
00230   else {
00231     /* No task is waiting for message, store the message to the mailbox queue.*/
00232     if (p_CB->count < p_CB->size) {
00233       p_CB->msg[p_CB->first] = p_msg;
00234       rt_inc (&p_CB->count);
00235       if (++p_CB->first == p_CB->size) {
00236         p_CB->first = 0;
00237       }
00238     }
00239     else {
00240       os_error (OS_ERR_MBX_OVF);
00241     }
00242   }
00243 }
00244 
00245 /*----------------------------------------------------------------------------
00246  * end of file
00247  *---------------------------------------------------------------------------*/
00248