mutex++
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Diff: rtx/rt_Semaphore.c
- Revision:
- 6:350b53afb889
- Child:
- 11:db1fc233faa9
diff -r 9654a71f5a90 -r 350b53afb889 rtx/rt_Semaphore.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/rtx/rt_Semaphore.c Fri Nov 23 09:57:31 2012 +0000 @@ -0,0 +1,183 @@ +/*---------------------------------------------------------------------------- + * RL-ARM - RTX + *---------------------------------------------------------------------------- + * Name: RT_SEMAPHORE.C + * Purpose: Implements binary and counting semaphores + * 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_Config.h" +#include "rt_System.h" +#include "rt_List.h" +#include "rt_Task.h" +#include "rt_Semaphore.h" +#include "rt_HAL_CM.h" + + +/*---------------------------------------------------------------------------- + * Functions + *---------------------------------------------------------------------------*/ + + +/*--------------------------- rt_sem_init -----------------------------------*/ + +void rt_sem_init (OS_ID semaphore, U16 token_count) { + /* Initialize a semaphore */ + P_SCB p_SCB = semaphore; + + p_SCB->cb_type = SCB; + p_SCB->p_lnk = NULL; + p_SCB->tokens = token_count; +} + + +/*--------------------------- rt_sem_delete ---------------------------------*/ + +#ifdef __CMSIS_RTOS +OS_RESULT rt_sem_delete (OS_ID semaphore) { + /* Delete semaphore */ + P_SCB p_SCB = semaphore; + P_TCB p_TCB; + + while (p_SCB->p_lnk != NULL) { + /* A task is waiting for token */ + p_TCB = rt_get_first ((P_XCB)p_SCB); + rt_ret_val(p_TCB, 0); + 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_SCB->cb_type = 0; + + return (OS_R_OK); +} +#endif + + +/*--------------------------- rt_sem_send -----------------------------------*/ + +OS_RESULT rt_sem_send (OS_ID semaphore) { + /* Return a token to semaphore */ + P_SCB p_SCB = semaphore; + P_TCB p_TCB; + + if (p_SCB->p_lnk != NULL) { + /* A task is waiting for token */ + p_TCB = rt_get_first ((P_XCB)p_SCB); +#ifdef __CMSIS_RTOS + rt_ret_val(p_TCB, 1); +#else + rt_ret_val(p_TCB, OS_R_SEM); +#endif + rt_rmv_dly (p_TCB); + rt_dispatch (p_TCB); + } + else { + /* Store token. */ + p_SCB->tokens++; + } + return (OS_R_OK); +} + + +/*--------------------------- rt_sem_wait -----------------------------------*/ + +OS_RESULT rt_sem_wait (OS_ID semaphore, U16 timeout) { + /* Obtain a token; possibly wait for it */ + P_SCB p_SCB = semaphore; + + if (p_SCB->tokens) { + p_SCB->tokens--; + return (OS_R_OK); + } + /* No token available: wait for one */ + if (timeout == 0) { + return (OS_R_TMO); + } + if (p_SCB->p_lnk != NULL) { + rt_put_prio ((P_XCB)p_SCB, os_tsk.run); + } + else { + p_SCB->p_lnk = os_tsk.run; + os_tsk.run->p_lnk = NULL; + os_tsk.run->p_rlnk = (P_TCB)p_SCB; + } + rt_block(timeout, WAIT_SEM); + return (OS_R_TMO); +} + + +/*--------------------------- isr_sem_send ----------------------------------*/ + +void isr_sem_send (OS_ID semaphore) { + /* Same function as "os_sem"send", but to be called by ISRs */ + P_SCB p_SCB = semaphore; + + rt_psq_enq (p_SCB, 0); + rt_psh_req (); +} + + +/*--------------------------- rt_sem_psh ------------------------------------*/ + +void rt_sem_psh (P_SCB p_CB) { + /* Check if task has to be waken up */ + P_TCB p_TCB; + + if (p_CB->p_lnk != NULL) { + /* A task is waiting for token */ + p_TCB = rt_get_first ((P_XCB)p_CB); + rt_rmv_dly (p_TCB); + p_TCB->state = READY; +#ifdef __CMSIS_RTOS + rt_ret_val(p_TCB, 1); +#else + rt_ret_val(p_TCB, OS_R_SEM); +#endif + rt_put_prio (&os_rdy, p_TCB); + } + else { + /* Store token */ + p_CB->tokens++; + } +} + +/*---------------------------------------------------------------------------- + * end of file + *---------------------------------------------------------------------------*/ +