rt_Mailbox.c

00001 /*----------------------------------------------------------------------------
00002  *      RL-ARM - RTX
00003  *----------------------------------------------------------------------------
00004  *      Name:    RT_MAILBOX.C
00005  *      Purpose: Implements waits and wake-ups for mailbox messages
00006  *      Rev.:    V4.60
00007  *----------------------------------------------------------------------------
00008  *
00009  * Copyright (c) 1999-2009 KEIL, 2009-2012 ARM Germany GmbH
00010  * All rights reserved.
00011  * Redistribution and use in source and binary forms, with or without
00012  * modification, are permitted provided that the following conditions are met:
00013  *  - Redistributions of source code must retain the above copyright
00014  *    notice, this list of conditions and the following disclaimer.
00015  *  - Redistributions in binary form must reproduce the above copyright
00016  *    notice, this list of conditions and the following disclaimer in the
00017  *    documentation and/or other materials provided with the distribution.
00018  *  - Neither the name of ARM  nor the names of its contributors may be used 
00019  *    to endorse or promote products derived from this software without 
00020  *    specific prior written permission.
00021  *
00022  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
00023  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
00024  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00025  * ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDERS AND CONTRIBUTORS BE
00026  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
00027  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
00028  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
00029  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
00030  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
00031  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00032  * POSSIBILITY OF SUCH DAMAGE.
00033  *---------------------------------------------------------------------------*/
00034 
00035 #include "rt_TypeDef.h"
00036 #include "RTX_Conf.h"
00037 #include "rt_System.h"
00038 #include "rt_List.h"
00039 #include "rt_Mailbox.h"
00040 #include "rt_MemBox.h"
00041 #include "rt_Task.h"
00042 #include "rt_HAL_CM.h"
00043 
00044 
00045 /*----------------------------------------------------------------------------
00046  *      Functions
00047  *---------------------------------------------------------------------------*/
00048 
00049 
00050 /*--------------------------- rt_mbx_init -----------------------------------*/
00051 
00052 void rt_mbx_init (OS_ID mailbox, U16 mbx_size) {
00053   /* Initialize a mailbox */
00054   P_MCB p_MCB = mailbox;
00055 
00056   p_MCB->cb_type = MCB;
00057   p_MCB->state   = 0;
00058   p_MCB->isr_st  = 0;
00059   p_MCB->p_lnk   = NULL;
00060   p_MCB->first   = 0;
00061   p_MCB->last    = 0;
00062   p_MCB->count   = 0;
00063   p_MCB->size    = (mbx_size + sizeof(void *) - sizeof(struct OS_MCB)) /
00064                                                      (U32)sizeof (void *);
00065 }
00066 
00067 
00068 /*--------------------------- rt_mbx_send -----------------------------------*/
00069 
00070 OS_RESULT rt_mbx_send (OS_ID mailbox, void *p_msg, U16 timeout) {
00071   /* Send message to a mailbox */
00072   P_MCB p_MCB = mailbox;
00073   P_TCB p_TCB;
00074 
00075   if ((p_MCB->p_lnk != NULL) && (p_MCB->state == 1)) {
00076     /* A task is waiting for message */
00077     p_TCB = rt_get_first ((P_XCB)p_MCB);
00078 #ifdef __CMSIS_RTOS
00079     rt_ret_val2(p_TCB, 0x10/*osEventMessage*/, (U32)p_msg);
00080 #else
00081     *p_TCB->msg = p_msg;
00082     rt_ret_val (p_TCB, OS_R_MBX);
00083 #endif
00084     rt_rmv_dly (p_TCB);
00085     rt_dispatch (p_TCB);
00086   }
00087   else {
00088     /* Store message in mailbox queue */
00089     if (p_MCB->count == p_MCB->size) {
00090       /* No free message entry, wait for one. If message queue is full, */
00091       /* then no task is waiting for message. The 'p_MCB->p_lnk' list   */
00092       /* pointer can now be reused for send message waits task list.    */
00093       if (timeout == 0) {
00094         return (OS_R_TMO);
00095       }
00096       if (p_MCB->p_lnk != NULL) {
00097         rt_put_prio ((P_XCB)p_MCB, os_tsk.run);
00098       }
00099       else {
00100         p_MCB->p_lnk = os_tsk.run;
00101         os_tsk.run->p_lnk  = NULL;
00102         os_tsk.run->p_rlnk = (P_TCB)p_MCB;
00103         /* Task is waiting to send a message */      
00104         p_MCB->state = 2;
00105       }
00106       os_tsk.run->msg = p_msg;
00107       rt_block (timeout, WAIT_MBX);
00108       return (OS_R_TMO);
00109     }
00110     /* Yes, there is a free entry in a mailbox. */
00111     p_MCB->msg[p_MCB->first] = p_msg;
00112     rt_inc (&p_MCB->count);
00113     if (++p_MCB->first == p_MCB->size) {
00114       p_MCB->first = 0;
00115     }
00116   }
00117   return (OS_R_OK);
00118 }
00119 
00120 
00121 /*--------------------------- rt_mbx_wait -----------------------------------*/
00122 
00123 OS_RESULT rt_mbx_wait (OS_ID mailbox, void **message, U16 timeout) {
00124   /* Receive a message; possibly wait for it */
00125   P_MCB p_MCB = mailbox;
00126   P_TCB p_TCB;
00127 
00128   /* If a message is available in the fifo buffer */
00129   /* remove it from the fifo buffer and return. */
00130   if (p_MCB->count) {
00131     *message = p_MCB->msg[p_MCB->last];
00132     if (++p_MCB->last == p_MCB->size) {
00133       p_MCB->last = 0;
00134     }
00135     if ((p_MCB->p_lnk != NULL) && (p_MCB->state == 2)) {
00136       /* A task is waiting to send message */
00137       p_TCB = rt_get_first ((P_XCB)p_MCB);
00138 #ifdef __CMSIS_RTOS
00139       rt_ret_val(p_TCB, 0/*osOK*/);
00140 #else
00141       rt_ret_val(p_TCB, OS_R_OK);
00142 #endif
00143       p_MCB->msg[p_MCB->first] = p_TCB->msg;
00144       if (++p_MCB->first == p_MCB->size) {
00145         p_MCB->first = 0;
00146       }
00147       rt_rmv_dly (p_TCB);
00148       rt_dispatch (p_TCB);
00149     }
00150     else {
00151       rt_dec (&p_MCB->count);
00152     }
00153     return (OS_R_OK);
00154   }
00155   /* No message available: wait for one */
00156   if (timeout == 0) {
00157     return (OS_R_TMO);
00158   }
00159   if (p_MCB->p_lnk != NULL) {
00160     rt_put_prio ((P_XCB)p_MCB, os_tsk.run);
00161   }
00162   else {
00163     p_MCB->p_lnk = os_tsk.run;
00164     os_tsk.run->p_lnk = NULL;
00165     os_tsk.run->p_rlnk = (P_TCB)p_MCB;
00166     /* Task is waiting to receive a message */      
00167     p_MCB->state = 1;
00168   }
00169   rt_block(timeout, WAIT_MBX);
00170 #ifndef __CMSIS_RTOS
00171   os_tsk.run->msg = message;
00172 #endif
00173   return (OS_R_TMO);
00174 }
00175 
00176 
00177 /*--------------------------- rt_mbx_check ----------------------------------*/
00178 
00179 OS_RESULT rt_mbx_check (OS_ID mailbox) {
00180   /* Check for free space in a mailbox. Returns the number of messages     */
00181   /* that can be stored to a mailbox. It returns 0 when mailbox is full.   */
00182   P_MCB p_MCB = mailbox;
00183 
00184   return (p_MCB->size - p_MCB->count);
00185 }
00186 
00187 
00188 /*--------------------------- isr_mbx_send ----------------------------------*/
00189 
00190 void isr_mbx_send (OS_ID mailbox, void *p_msg) {
00191   /* Same function as "os_mbx_send", but to be called by ISRs. */
00192   P_MCB p_MCB = mailbox;
00193 
00194   rt_psq_enq (p_MCB, (U32)p_msg);
00195   rt_psh_req ();
00196 }
00197 
00198 
00199 /*--------------------------- isr_mbx_receive -------------------------------*/
00200 
00201 OS_RESULT isr_mbx_receive (OS_ID mailbox, void **message) {
00202   /* Receive a message in the interrupt function. The interrupt function   */
00203   /* should not wait for a message since this would block the rtx os.      */
00204   P_MCB p_MCB = mailbox;
00205 
00206   if (p_MCB->count) {
00207     /* A message is available in the fifo buffer. */
00208     *message = p_MCB->msg[p_MCB->last];
00209     if (p_MCB->state == 2) {
00210       /* A task is locked waiting to send message */
00211       rt_psq_enq (p_MCB, 0);
00212       rt_psh_req ();
00213     }
00214     rt_dec (&p_MCB->count);
00215     if (++p_MCB->last == p_MCB->size) {
00216       p_MCB->last = 0;
00217     }
00218     return (OS_R_MBX);
00219   }
00220   return (OS_R_OK);
00221 }
00222 
00223 
00224 /*--------------------------- rt_mbx_psh ------------------------------------*/
00225 
00226 void rt_mbx_psh (P_MCB p_CB, void *p_msg) {
00227   /* Store the message to the mailbox queue or pass it to task directly. */
00228   P_TCB p_TCB;
00229   void *mem;
00230 
00231   if (p_CB->p_lnk != NULL) switch (p_CB->state) {
00232 #ifdef __CMSIS_RTOS
00233     case 3:
00234       /* Task is waiting to allocate memory, remove it from the waiting list */
00235       mem = rt_alloc_box(p_msg);
00236       if (mem == NULL) break;
00237       p_TCB = rt_get_first ((P_XCB)p_CB);
00238       rt_ret_val(p_TCB, (U32)mem);
00239       p_TCB->state = READY;
00240       rt_rmv_dly (p_TCB);
00241       rt_put_prio (&os_rdy, p_TCB);
00242       break;
00243 #endif
00244     case 2:
00245       /* Task is waiting to send a message, remove it from the waiting list */
00246       p_TCB = rt_get_first ((P_XCB)p_CB);
00247 #ifdef __CMSIS_RTOS
00248       rt_ret_val(p_TCB, 0/*osOK*/);
00249 #else
00250       rt_ret_val(p_TCB, OS_R_OK);
00251 #endif
00252       p_CB->msg[p_CB->first] = p_TCB->msg;
00253       rt_inc (&p_CB->count);
00254       if (++p_CB->first == p_CB->size) {
00255         p_CB->first = 0;
00256       }
00257       p_TCB->state = READY;
00258       rt_rmv_dly (p_TCB);
00259       rt_put_prio (&os_rdy, p_TCB);
00260       break;
00261     case 1:
00262       /* Task is waiting for a message, pass the message to the task directly */
00263       p_TCB = rt_get_first ((P_XCB)p_CB);
00264 #ifdef __CMSIS_RTOS
00265       rt_ret_val2(p_TCB, 0x10/*osEventMessage*/, (U32)p_msg);
00266 #else
00267       *p_TCB->msg = p_msg;
00268       rt_ret_val (p_TCB, OS_R_MBX);
00269 #endif
00270       p_TCB->state = READY;
00271       rt_rmv_dly (p_TCB);
00272       rt_put_prio (&os_rdy, p_TCB);
00273       break;
00274   } else {
00275       /* No task is waiting for a message, store it to the mailbox queue */
00276       if (p_CB->count < p_CB->size) {
00277         p_CB->msg[p_CB->first] = p_msg;
00278         rt_inc (&p_CB->count);
00279         if (++p_CB->first == p_CB->size) {
00280           p_CB->first = 0;
00281         }
00282       }
00283       else {
00284         os_error (OS_ERR_MBX_OVF);
00285       }
00286   }
00287 }
00288 
00289 /*----------------------------------------------------------------------------
00290  * end of file
00291  *---------------------------------------------------------------------------*/
00292