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.:    V4.50
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_Config.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->state == 1) {
00076     /* A task is waiting for message */
00077     p_TCB = rt_get_first ((P_XCB)p_MCB);
00078     if (p_MCB->p_lnk == NULL) {
00079       p_MCB->state = 0;
00080     }
00081     rt_ret_val2(p_TCB, 0x10/*osEventMessage*/, (U32)p_msg);
00082     rt_rmv_dly (p_TCB);
00083     rt_dispatch (p_TCB);
00084   }
00085   else {
00086     /* Store message in mailbox queue */
00087     if (p_MCB->count == p_MCB->size) {
00088       /* No free message entry, wait for one. If message queue is full, */
00089       /* then no task is waiting for message. The 'p_MCB->p_lnk' list   */
00090       /* pointer can now be reused for send message waits task list.    */
00091       if (timeout == 0) {
00092         return (OS_R_TMO);
00093       }
00094       if (p_MCB->p_lnk != NULL) {
00095         rt_put_prio ((P_XCB)p_MCB, os_tsk.run);
00096       }
00097       else {
00098         p_MCB->p_lnk = os_tsk.run;
00099         os_tsk.run->p_lnk  = NULL;
00100         os_tsk.run->p_rlnk = (P_TCB)p_MCB;
00101         /* Task is waiting to send a message */      
00102         p_MCB->state = 2;
00103       }
00104       os_tsk.run->msg = p_msg;
00105       rt_block (timeout, WAIT_MBX);
00106       return (OS_R_TMO);
00107     }
00108     /* Yes, there is a free entry in a mailbox. */
00109     p_MCB->msg[p_MCB->first] = p_msg;
00110     rt_inc (&p_MCB->count);
00111     if (++p_MCB->first == p_MCB->size) {
00112       p_MCB->first = 0;
00113     }
00114   }
00115   return (OS_R_OK);
00116 }
00117 
00118 
00119 /*--------------------------- rt_mbx_wait -----------------------------------*/
00120 
00121 OS_RESULT rt_mbx_wait (OS_ID mailbox, void **message, U16 timeout) {
00122   /* Receive a message; possibly wait for it */
00123   P_MCB p_MCB = mailbox;
00124   P_TCB p_TCB;
00125 
00126   /* If a message is available in the fifo buffer */
00127   /* remove it from the fifo buffer and return. */
00128   if (p_MCB->count) {
00129     *message = p_MCB->msg[p_MCB->last];
00130     if (++p_MCB->last == p_MCB->size) {
00131       p_MCB->last = 0;
00132     }
00133     if (p_MCB->state == 2) {
00134       /* A task is waiting to send message */
00135       p_TCB = rt_get_first ((P_XCB)p_MCB);
00136       if (p_MCB->p_lnk == NULL) {
00137         p_MCB->state = 0;
00138       }
00139       rt_ret_val(p_TCB, 0/*osOK*/);
00140       p_MCB->msg[p_MCB->first] = p_TCB->msg;
00141       if (++p_MCB->first == p_MCB->size) {
00142         p_MCB->first = 0;
00143       }
00144       rt_rmv_dly (p_TCB);
00145       rt_dispatch (p_TCB);
00146     }
00147     else {
00148       rt_dec (&p_MCB->count);
00149     }
00150     return (OS_R_OK);
00151   }
00152   /* No message available: wait for one */
00153   if (timeout == 0) {
00154     return (OS_R_TMO);
00155   }
00156   if (p_MCB->p_lnk != NULL) {
00157     rt_put_prio ((P_XCB)p_MCB, os_tsk.run);
00158   }
00159   else {
00160     p_MCB->p_lnk = os_tsk.run;
00161     os_tsk.run->p_lnk = NULL;
00162     os_tsk.run->p_rlnk = (P_TCB)p_MCB;
00163     /* Task is waiting to receive a message */      
00164     p_MCB->state = 1;
00165   }
00166   rt_block(timeout, WAIT_MBX);
00167   return (OS_R_TMO);
00168 }
00169 
00170 
00171 /*--------------------------- rt_mbx_check ----------------------------------*/
00172 
00173 OS_RESULT rt_mbx_check (OS_ID mailbox) {
00174   /* Check for free space in a mailbox. Returns the number of messages     */
00175   /* that can be stored to a mailbox. It returns 0 when mailbox is full.   */
00176   P_MCB p_MCB = mailbox;
00177 
00178   return (p_MCB->size - p_MCB->count);
00179 }
00180 
00181 
00182 /*--------------------------- isr_mbx_send ----------------------------------*/
00183 
00184 void isr_mbx_send (OS_ID mailbox, void *p_msg) {
00185   /* Same function as "os_mbx_send", but to be called by ISRs. */
00186   P_MCB p_MCB = mailbox;
00187 
00188   rt_psq_enq (p_MCB, (U32)p_msg);
00189   rt_psh_req ();
00190 }
00191 
00192 
00193 /*--------------------------- isr_mbx_receive -------------------------------*/
00194 
00195 OS_RESULT isr_mbx_receive (OS_ID mailbox, void **message) {
00196   /* Receive a message in the interrupt function. The interrupt function   */
00197   /* should not wait for a message since this would block the rtx os.      */
00198   P_MCB p_MCB = mailbox;
00199 
00200   if (p_MCB->count) {
00201     /* A message is available in the fifo buffer. */
00202     *message = p_MCB->msg[p_MCB->last];
00203     if (p_MCB->state == 2) {
00204       /* A task is locked waiting to send message */
00205       rt_psq_enq (p_MCB, 0);
00206       rt_psh_req ();
00207     }
00208     rt_dec (&p_MCB->count);
00209     if (++p_MCB->last == p_MCB->size) {
00210       p_MCB->last = 0;
00211     }
00212     return (OS_R_MBX);
00213   }
00214   return (OS_R_OK);
00215 }
00216 
00217 
00218 /*--------------------------- rt_mbx_psh ------------------------------------*/
00219 
00220 void rt_mbx_psh (P_MCB p_CB, void *p_msg) {
00221   /* Store the message to the mailbox queue or pass it to task directly. */
00222   P_TCB p_TCB;
00223   void *mem;
00224 
00225   switch (p_CB->state) {
00226     case 3:
00227       /* Task is waiting to allocate memory, remove it from the waiting list */
00228       mem = rt_alloc_box(p_msg);
00229       if (mem == NULL) break;
00230       p_TCB = rt_get_first ((P_XCB)p_CB);
00231       if (p_CB->p_lnk == NULL) {
00232         p_CB->state = 0;
00233       }
00234       rt_ret_val(p_TCB, (U32)mem);
00235       p_TCB->state = READY;
00236       rt_rmv_dly (p_TCB);
00237       rt_put_prio (&os_rdy, p_TCB);
00238       break;
00239     case 2:
00240       /* Task is waiting to send a message, remove it from the waiting list */
00241       p_TCB = rt_get_first ((P_XCB)p_CB);
00242       if (p_CB->p_lnk == NULL) {
00243         p_CB->state = 0;
00244       }
00245       rt_ret_val(p_TCB, 0/*osOK*/);
00246       p_CB->msg[p_CB->first] = p_TCB->msg;
00247       rt_inc (&p_CB->count);
00248       if (++p_CB->first == p_CB->size) {
00249         p_CB->first = 0;
00250       }
00251       p_TCB->state = READY;
00252       rt_rmv_dly (p_TCB);
00253       rt_put_prio (&os_rdy, p_TCB);
00254       break;
00255     case 1:
00256       /* Task is waiting for a message, pass the message to the task directly */
00257       p_TCB = rt_get_first ((P_XCB)p_CB);
00258       if (p_CB->p_lnk == NULL) {
00259         p_CB->state = 0;
00260       }
00261       rt_ret_val2(p_TCB, 0x10/*osEventMessage*/, (U32)p_msg);
00262       p_TCB->state = READY;
00263       rt_rmv_dly (p_TCB);
00264       rt_put_prio (&os_rdy, p_TCB);
00265       break;
00266     default:
00267       /* No task is waiting for a message, store it to the mailbox queue */
00268       if (p_CB->count < p_CB->size) {
00269         p_CB->msg[p_CB->first] = p_msg;
00270         rt_inc (&p_CB->count);
00271         if (++p_CB->first == p_CB->size) {
00272           p_CB->first = 0;
00273         }
00274       }
00275       else {
00276         os_error (OS_ERR_MBX_OVF);
00277       }
00278       break;
00279   }
00280 }
00281 
00282 /*----------------------------------------------------------------------------
00283  * end of file
00284  *---------------------------------------------------------------------------*/
00285